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# Physics of fundamental Symmetries and Interactions - PSI2019
20-25 October 2019
PSI
Europe/Zurich timezone
## The BL2 Experiment: An In-Beam Measurement of the Neutron Lifetime
24 Oct 2019, 15:20
20m
WHGA/001 - Auditorium (PSI)
Oral
### Speaker
Jimmy Caylor (The University of Tennessee - Knoxville)
### Description
Neutron beta decay is the simplest example of semi-leptonic decay. A precise measurement of the neutron lifetime and $\lambda$, the ratio of axial vector and vector coupling constants of the weak interaction, allow for a determination of the CKM matrix element $V_{ud}$ that is free from nuclear structure effects. The neutron lifetime provides an important test of unitarity and consistency of the Standard Model. The neutron lifetime is also the largest uncertainty in Big Bang Nucleosynthesis calculations of light element abundance. A new measurement of the neutron lifetime using the in-beam method is ongoing at the NIST Center for Neutron Research. This method requires the absolute counting of the decay protons in a neutron beam of precisely known flux. Improvements in the neutron and proton detection systems as well as the use of a new analysis technique should allow for a thorough investigation of major systemic effects. The experimental status, systematic tests, analysis techniques and early data will be presented.
### Primary author
Jimmy Caylor (The University of Tennessee - Knoxville)
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# Overview¶
Queueing-tool is a Python simulation package for analyzing networks of queues. The simulations are event based, where events are comprised as arrivals and departures of agents that move from queue to queue in the network. The network is represented as a graph, which is handled by NetworkX.
There are three major components to queueing-tool: the QueueServer classes, Agent classes, and QueueNetwork class. This package includes several different types of each class.
1. The QueueServer class is a standard implementation of a waiting line. Its basic function is facilitating the arrival of agents — which arrive with some regularity according to some distribution — and servicing those agents before they leave. Each queue can have any arrival and service distribution, and these distributions can depend on time. Two such implemented are the following:
• The QueueServer class can have any positive number of servers (including infinitely many). There can also be a maximum number of potential arrivals to the queue. In Kendall’s notation, these are $$\text{GI}_t/\text{GI}_t/c/\infty/N/\text{FIFO}$$ queues.
• The LossQueue class is an implementation of a finite capacity queue. It has all the features of the QueueServer class but also implements blocking (or loss). This class can be used to simulate loss networks. In Kendall’s notation, these are $$\text{GI}_t/\text{GI}_t/c/c+b/N/\text{FIFO}$$ queues.
2. An Agent is an object that moves throughout the network. When an instance of the network is created it starts empty. Agents are created by a queue and once serviced the agent moves on to another queue in the network. Each agent decides where in the network it wants to arrive at next. Two examples of the agent implementation are:
• The Agent class routes itself throughout the network randomly. More specifically, when at node i in the network, the Agent decides to transition to node j with probability $$p_{ij}$$. The user has control over setting the transition probabilities, which can be done using the network’s set_transitions() method.
• The GreedyAgent class routes itself by choosing the queue with the shortest line.
3. The QueueNetwork class manages the routing of agents from queue to queue. It can also manage congestion and blocking within the network. There are two blocking regimes implemented:
• Blocking After Service: when an agent attempts to enter a LossQueue that is at capacity, the agent is forced to wait until an agent departs from that queue.
• Repetitive Service Blocking: when an agent attempts to enter a LossQueue that is at capacity, the agent is forced to receive another service from its current queue. This process is repeated until the agent’s desired queue is no longer at capacity.
One can also limit the maximum number of agents within the system.
This package also contains a visualization component, whereby the user can see queueing dynamics in real-time as the simulations take place. See animate() and draw() for more on this package’s visualization capabilities.
## An example¶
It’s probably best to become acquainted with queueing-tool by way of an example.
Let’s model the checkout process of a busy grocery store. People enter the store according to some random process, shop around for some time, and then checkout. They also arrive at a greater frequency in the middle of the day. When it’s time to checkout, customers choose their checkout line by searching for the shortest line. They wait in line before receiving service from the checkout counter and when they’re done they leave the store.
In queueing-tool, each person entering the system is represented as an Agent. Each Agent decides how they navigate in the network. In this system an Agent chooses the shortest queue to enter at whenever they choose which queue to arrive at next. The GreedyAgent class is built to model such routing.
The network is represented as a networkx.DiGraph. On top of each edge in the graph sits the queues, where each queue is represented as a QueueServer. In our model, each checkout line is it’s own QueueServer. These checkout queues receive arrivals from people who are already in the store. The store receives arrivals from the neighborhood, and after some time they go to the checkout area. This is a relatively, simple network that is easy to create using queueing-tool.
To create the network you need to specify an adjacency list (or adjacency matrix). In our toy example, we are going to assume the store has 20 checkout lines. Let’s get started:
>>> import queueing_tool as qt
>>> import numpy as np
>>> adja_list = {0: [1], 1: [k for k in range(2, 22)]}
This says that node 0 points to node one, and node 1 points to nodes 2 through 21. Now in our simple system there are three types of queues, the two important ones are: checkout queues, and the queue that represents the store shopping area. The third type represents agents leaving the store and is handled automatically by queueing_tool. To specify what type of queue sits on each edge, you specify an adjacency list like object:
>>> edge_list = {0: {1: 1}, 1: {k: 2 for k in range(2, 22)}}
This says there are two main types of queues/edges, type 1 and type 2. All the checkout lines are of type 2 while the store queue (the edge connecting vertex zero to vertex one) is type 1. The queue that represents agents leaving the store are type 0 queues, and is handled automatically by queueing-tool. Now we can make our graph:
So we’ve created a graph where each edge/queue has a type. Since our edge of type 1 represents the store, it will accept shoppers from outside the network. We will take the arrival process to be time varying and random (more specifically, we’ll let it be a non-homogeneous Poisson process), with a rate that’s sinusoidal. To set that, run:
>>> def rate(t):
... return 25 + 350 * np.sin(np.pi * t / 2)**2
>>> def arr_f(t):
... return qt.poisson_random_measure(t, rate, 375)
Lastly, we need to specify the departure process for each checkout counter. Let’s choose the exponential distribution:
>>> def ser_f(t):
... return t + np.random.exponential(0.2 / 2.1)
Now is time to put this all together to make out queueing network; we do this with the following:
>>> q_classes = {1: qt.QueueServer, 2: qt.QueueServer}
>>> q_args = {
... 1: {
... 'arrival_f': arr_f,
... 'service_f': lambda t: t,
... 'AgentFactory': qt.GreedyAgent
... },
... 2: {
... 'num_servers': 1,
... 'service_f': ser_f
... }
... }
>>> qn = qt.QueueNetwork(g=g, q_classes=q_classes, q_args=q_args, seed=13)
For simplicity, we’ve made it so that when a customer enters the store they immediately try to checkout.
The default layout was a little hard on the eyes so I changed it a little:
>>> qn.g.new_vertex_property('pos')
>>> pos = {}
>>> for v in qn.g.nodes():
... if v == 0:
... pos[v] = [0, 0.8]
... elif v == 1:
... pos[v] = [0, 0.4]
... else:
... pos[v] = [-5. + (v - 2.0) / 2, 0]
...
>>> qn.g.set_pos(pos)
To view the model (using this layout), do the following:
>>> qn.draw(figsize=(12, 3))
<...>
The network is empty so the edges are light. Use the following code if you want to save this image to disk:
>>> qn.draw(fname="store.png", figsize=(12, 3), bbox_inches='tight')
By default, each QueueServer starts with no arrivals from outside the network and it needs to be initialized before any simulations can run. You can specify which queues allow arrivals from outside the system with QueueNetwork's initialize() function. In this example, we only want agents arriving from the type 1 edge so we do the following:
>>> qn.initialize(edge_type=1)
To simulate for a specified amount of simulation time run:
>>> qn.simulate(t=1.9)
>>> qn.num_events
1167
>>> qn.draw(fname="sim.png", figsize=(12, 3), bbox_inches='tight')
<...>
The darker edges represent greater congestion at that checkout counter.
If you want to save the arrival, departure, and service start times of arrivals you have to tell it to do so:
>>> qn.start_collecting_data()
>>> qn.simulate(t=1.8)
>>> data = qn.get_queue_data()
>>> data.shape
(2261, 6)
The above data also include the number of agent in the queue upon arrival to a queue (this includes the number of agents receiving service and the number of agents waiting). If we only care about data concerning those exiting the system we can specify that by having type 0 edges collect data:
>>> qn.clear_data()
>>> qn.start_collecting_data(edge_type=0)
>>> qn.simulate(t=3)
>>> data = qn.get_queue_data(edge_type=0)
>>> data.shape
(575, 6)
The above code collected the departure times of every agent over the simulated period, it did not collect each agent’s arrival or waiting time. See get_queue_data() and start_collecting_data() for more on extracting data.
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# Orthogonal vector
## Homework Statement
Construct a third vector which is orthogonal to the following pair and normalize all three vectors:
$$\underline{a}=(1-i,1,3i), \underline{b}=(1+2i,2,1)$$
## Homework Equations
$$\underline{c}.\underline{a}=0$$ and $$\underline{c}.\underline{b}=0$$ where c=(x y z)
## The Attempt at a Solution
Mark44
Mentor
Your relevant equations are a good start, so use them.
The question is, how do we make a dot product when the vectors are complex? Is it the same way as real vectors or not?
Mark44
Mentor
Do it the same way.
Dick
Homework Helper
Do it the same way.
Not exactly. You take the complex conjugate of the first vector before you multiply the components. Otherwise <x,x>>=0 doesn't work.
Not exactly. You take the complex conjugate of the first vector before you multiply the components. Otherwise <x,x>>=0 doesn't work.
I'm not familiar with complex vectors, but since you want a vector that is orthogonal to both, rather than trying two dot products, wouldn't it be prudent to use a cross product?
HallsofIvy
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## International Journal of Nursing and Health Care Research (ISSN: 2688-9501)
### Article / research article
Lark A. Ford*
School of Nursing, University of Texas Health Science Center at San Antonio, Texas, USA
*Corresponding author: Lark A. Ford, School of Nursing, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive San Antonio, TX 78229, USA. Tel: +1-2105670838; Email: [email protected]
Received Date: 25 April, 2019; Accepted Date: 20 May, 2019; Published Date: 27 May, 2019
Abstract
The purpose of this descriptive study was to examine the perception of readiness for discharge from a transitional living center of six homeless adult family members with cardiac conditions. Three constructs formed the framework for this study: (a) being homeless, (b) undergoing severe stress, and (c) being ready for discharge. Four data collection instruments used for this study included (a) a 10-item, Self-Perceived Stress Scale to assess perception of stress over a one-month time period; (b) a pencil-and-paper, self-description of respondents’ cardiac health condition over time; (c) a retrospective, medical chart review on each respondent; and (d) a one-hour, face-to-face interview with each study volunteer. Findings showed that all of the homeless participants experienced high levels of stress, yet those participants who resided in the transitional living center in their early and later months experienced higher levels of stress than those participants who resided in the transitional living center between 12 to 18 months. One key theme emerged regarding their perception toward readiness for discharge: being safe and securing housing. The adult members’ overall perception regarding their health contributed very little to their self-perceptions of being ready for discharge.
Keywords: Being homeless; Readiness for discharge; Undergoing stress
Introduction
Around the world, more than 100 million people are homeless and homelessness is a growing public health concern [1,2]. According to the Stewart B. McKinney Act, U.S.C. §11301 of 1994, A person is considered homeless who lacks a fixed, regular, and adequate night-time residence, and requires a primary night time residency that is: 1) a supervised, publicly or privately operated shelter designed to provide temporary living accommodations; 2) an institution that provides a temporary residence for individuals intended to be institutionalized; or, 3) a public or private place not designed for, or ordinarily used as, a regular sleeping accommodation for human beings [3]. In the early 1980s, most homeless people were men. In today’s world, people experiencing or at risk for homelessness also include women with two children under the age of 5 [1,2,4]. Homeless people are a heterogeneous population whose diverse health needs are poorly met [1,2,4]. This vulnerable population’s specific health needs differ from those of the general population [1]. People who are homeless suffer from disproportionately high rates of chronic and infectious diseases, such as Human Immunodeficiency Virus (HIV), Acquired Immune-Deficiency Syndrome (AIDS), hepatic diseases, cardiovascular disease, and diabetes. In this regard, homeless populations experience higher mortality rates and lower life expectancies than housed populations [1,2,4].
Family homelessness has emerged as a serious challenge in the United States [5] and presents considerable barriers to the maintenance of family processes [6]. It is critical to understand families’ readiness to change their lifestyle status from homelessness toward re-engagement into mainstream society given the importance of these processes to individual and family well-being. Readiness to change is defined as a commitment and motivation to make health-related, behavioral, or lifestyle changes [7]. Core areas that focus on readiness include undergoing changes that can improve and build on an individual’s basic life-skills, such as education, financial counseling, and parenting skills. Other areas include the improvement in one’s physical and mental health status. Maycock, et al. [8] suggested that, for some, reentry into society or moving out of homelessness involves access to and engagement in drug treatment services and participation in education and training. Kurtz, et al. [9] found that young people resolved their homelessness through support from family, friends, and professional helpers.
Purpose
Based on these conditions and factors, the purpose of this qualitative, descriptive study was to examine the perception of adult members of homeless families regarding their readiness to return to mainstream society after being homeless and residing in a transitional living environment. The selected adults were those diagnosed with cardiac conditions or at risk for such medical conditions as hypertension (blood pressure greater than 120/80 mm Hg), and/or hypercholesterolemia/elevated cholesterol level (level higher than 240 mg/dL), and living as a family.
Background
Homeless individuals or families are in dire situations when faced with challenging job markets, a shortage of affordable housing, and restricted access to health care and possible domestic violence [10]. Individuals or families who are not classified as being homeless may become homeless due to an unforeseen loss of a job or by developing a catastrophic illness. Despite numerous programs and initiatives for the homeless, findings suggest conflicting results of success and unsuccessful outcomes of homeless persons being able to reenter mainstream society, even after participating in those initiatives [8,11].
National Statistics: Report from the U.S. Department of Housing and Urban Development (HUD) indicates that 610,000 people experienced homelessness on any given night in the United States [3]. In 2011, the National Center on Family Homelessness reported that 31% of this population represented families. In a given year, 3.5 million persons will experience homelessness and 1.35 million are children [12]. Among homeless women, 60% parent children under the age of 18, and among homeless men, 41% are fathers with children under the age of 18 years.
Homeless Women: Upshur et al. [13] reported that women are at greater risk for homelessness and show a high prevalence for using alcohol and illegal drugs-5 to 14 times higher than the general population of women. These researchers reported that homeless women with alcohol or drug abuse disorders with prolonged episodes of homelessness did not seek assistance from addiction services. Reasons included lack of motivation to quit using alcohol or drugs, poor mental health, emotional distress, and depression.
Homeless Families: In 201l, in an unprecedented event, the U.S. government recognized that homelessness was a human rights concern and that the government had an obligation to address this issue. According to America’s Youngest Outcasts, a report on homelessness among American children compiled by the National Center on Family Homelessness [14] indicated that more than 1.6 million children, or 1 in 45, are homeless annually in America-approximately 30,000 children each week and more than 4,400 each day. The average length of time for people being homeless was 6 months [12]. A 2008 U.S. Conference of Mayors Report indicated that 19 of the 25 cities studied reported an increase in homelessness from year 2007. Stimulated in part by this acknowledgement, an increase may occur in programs to meet the health needs of the homeless over the next decade [10].
Homelessness in Texas: In Texas, according to the U.S. Department of Housing and Urban Development, 29,615 people were classified as homeless in 2013, or 12 out of every 10,000 persons in Texas [12]. In San Antonio, Texas, the number of homeless individuals and families is growing; 31% of these were classified as families.
Transitional Living Centers for Homeless People
Transitional living centers for homeless persons included providing transitional housing and three meals a day. These transitional living centers also focused on providing residents with employment and financial counseling, education, training, and health care. The average length of stay for residents in these centers was between 21 to 24 months.
Significance
This study was important because the increasing population of homeless individuals and families across the country has continued to multiply, as well as the health needs for this vulnerable population. The Centers for Disease Control and Prevention [15] reported that in 2002, 12.3% of the general worldwide population perceived their own health status as poor. In 2009, the health status of homeless persons was much lower than the general population [10]. Poor physical health was associated with poverty in general, but seemed to be more pronounced among those who were without homes. Additionally, poor physical health was associated with higher rates of tuberculosis, hypertension, asthma, diabetes, and HIV/AIDs, as well as higher rates of medical hospitalizations [16].
In a national study, 73% of homeless adults reported at least one unmet health need [1]. The most commonly reported unmet needs of homeless adults were inability to (a) access needed medical or surgical care (32%), (b) purchase prescription medications (36%), (c) receive mental health care (21%), (d) acquire eyeglasses (41%), and (e) access dental care (41%).
Cost of Health Care for the Homeless: According to the National Coalition for Homelessness [10], the 2007 U.S. Census Bureau calculated that 45.7 million Americans (15.3% of the population) were without any form of health insurance. In 2007, 26.8 million people (18.1%) who worked part-time or full-time during the previous year were uninsured including 21.1 million full-time workers. Of the 45.7 million uninsured Americans, 34.6 million identified as part of a family. Homeless people experienced worse levels of physical and mental health than the general population [17]. Among the homeless, the three leading causes of death were (a) cardiovascular/heart disease, (b) chronic lower respiratory diseases, and (c) cerebrovascular disease. These major causes accounted for 75% of all deaths occurring in the United States [18].
Cardiovascular/heart disease was a major cause of mortality in adults between 45 and 64 years old and this health condition was three times more common in the homeless aged 25 to 44 years when compared to an age-matched sample in the general population [18]. Increased cardiovascular mortality rates in the homeless were attributable to a complex relationship between traditional and less traditional risks [19]. These risks included the pervasive, immeasurable, psychosocial stressors linked to the daily challenges of obtaining the necessities of life including food, shelter, and safety. These challenges along with a decrease in access to health care resulted in an increased prevalence of and/or poor control of the traditional risk factors and other co-morbidities [19]. Long-term solutions that address the links between homelessness and cardiovascular disease are associated with measures that prevent homelessness and/or reverse the trends in our health care system that creates disparities among the poor and homeless population. Other prevalent health conditions among the homeless were drug and alcohol dependence, mental illness, physical trauma, and dental cavities.
Morbidity and Mortality: Homeless persons were at a higher risk for morbidity and mortality from both chronic and episodic illness than the general population [20,21]. The risk of homeless persons being hospitalized were twice as high for men than women [20]. Substance-using homeless persons frequented emergency departments and hospitals more often than the general population [22]. However, little is known about the ways in which the homeless are affected when this population seeks care for Substance Abuse Treatment (SAT). O’Toole et al. [22] surveyed 266 homeless and 104 non-homeless substance-using adults who were sequentially admitted to an urban hospital medical service. The homeless respondents were younger, had less than a high school education, were uninsured, and experienced additional health-related issues, which included hepatitis B and C.
Reflexivity
What motivated me to explore the topic of homeless families is having had one of my family members experience homelessness without me having full knowledge that it had occurred. As the proverbial statement goes, “Anyone could be on the brink of homelessness if faced with a serious illness or loss of a job.” This was the case with my family member. She was 37 years old at the time of her death, a single mother, with a high school education and sole source of income for her 8-year-old son. She was pursuing a career in health care as a Certified Nursing Assistant when she became seriously ill with flu-like symptoms. Her illness became more serious and she was hospitalized until her death 6 months later. Her spouse was unable to maintain a full-time job while caring for his son and visiting his hospitalized wife. His son reportedly felt secure because he was with his father and did not realize until years later that he had been living in poverty and a state of homelessness when he and his father would sleep at a different location every night. Just when I thought being homeless could not affect anyone in my family, it did. This was, in part, what motivated me to become more aware of transitional living centers for other families and the services that are provided.
Conceptual Framework
The conceptual framework that informed this study was located at the intersection of the three constructs: (a) being homeless, (b) undergoing severe stress, and (c) being ready for discharge.
Being Homeless: Being homeless describes an individual in a supervised, publicly or privately-operated shelter designed to provide temporary living arrangements (including hotels and motels) paid for by the federal, state, or local government programs for low-income individuals, or by charitable organizations, congregate shelters, and transitional housing. Homeless people are unable to acquire and maintain regular, safe, secure, and adequate housing, or they lack a fixed, regular, and adequate nighttime residence [3]. In addition, homeless people are particularly at risk for stress. For this study, being homeless refers to an adult family member, who is the sole source of income for the family and has a confirmed cardiac/heart condition such as hypertension and/or hypercholesterolemia/elevated cholesterol level and living in a transitional living center.
Undergoing Severe Stress: Stress is defined here as a non-specific response of the body to any demand for change [23]. Stress is the state manifested by a specific syndrome that consists of all non-specifically induced changes within a biologic system. Stress has its own characteristic form and composition, but no particular cause. Human beings cannot go through life without stress. “Stress is as much a part of life as breathing and eating” [24]. Homeless people are faced with a combination of internal and external stressors that trigger other mediating factors such as high blood pressure that affect their ability to focus on transitioning or returning to mainstream society from a homeless status. Additional stressors include residing in unfamiliar surroundings such as temporary shelters that are overcrowded, noisy, and lack privacy, as well as economic inadequacies-all contributing factors [23]. Mediating factors may include other physiological changes such as headache and nutritional deficiency. The state of homelessness increases the likelihood of families separating that can further compound stress placed on them. Life changes, whether they are positive or negative, require people to expend energy to adapt to change.
Chronic psychological stress is associated with the body losing its ability to regulate the inflammatory response. Inflammation is partially regulated by the anti-inflammatory hormone, cortisol that protects the body from prolonged periods of inflammation. When cortisol is not allowed to serve its function of impeding the inflammatory process, then inflammation can get out of control [24,25]. Just as cortisol protects the body from inflammation, the production of cortisol is also related to stress. Cortisol also affects the immune system, whereas the immune system affects stress. Prolonged stress alters the effectiveness of cortisol to regulate the inflammatory response because it decreases tissue sensitivity to the hormone. Specifically, immune cells become insensitive to cortisol’s regulatory effect. In short, inflammation is thought to promote the development and progression of many diseases [26].
Two syndromes occur in response to stress. The first occurs as a Local Adaptation Syndrome (LAS); the second occurs as a general adaptation syndrome [23]. The LAS is a short-term, localized response to a specific stressor such as a response of body tissue to trauma, illness, or other physiological changes [24]. For example, when a person places his hand on top of a hot stove, a localized pain response occurs with an immediate reflex that removes one’s hand from the hot surface. The manner in which an individual respond to a stressful situation is mediated by such factors as personality, perception of stressors, and one’s coping abilities. Factors influencing one’s response to stressors include the intensity of the stressor; that is, the greater the magnitude of the stressor, the greater the stress response; the scope in which the stress encompasses a person’s total well-being, the greater the scope of the stress, the greater the response to the stress; and, lastly, the duration and the number of stressors an individual face [23,24].
The GAS is defined as a physiologic response of a person’s whole body to stress. The GAS emerges when people experience stress or illness. The GAS reflects a general response that occurs in various parts of the body. The GAS consists of three stages: (a) the alarm reaction, (b) the resistance stage, and (c) the exhaustion stage. The alarm reaction stage causes the body to react physiologically-increasing hormone levels, heart rate and cardiac output, respiratory rate, oxygen intake, and mental energy. The resistance stage begins as a person adapts to his/her stressors. The third stage of adaptation may occur and manifest as exhaustion; during this stage, the body is drained of energy and can no longer defend itself against the stressor. Either the stress is reduced or the person dies. Selye’s LAS and GAS and the other constructs that informed this study (being homeless and being ready for change) formed the elements for this study’s conceptual framework. The phenomenon of undergoing/engaging change is critical to one’s survival and thriving. Health is defined here as the state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity [27]. Health is a state of equilibrium among the subsystems of the holistic person. Included in a person’s health are one’s beliefs about the quality of his/her life, ability to find meaning in life, and ability to maintain a positive, future orientation [24].
Being Homeless and Undergoing Severe Stress: For this study, the stressors of interest focus on the phenomenon of being homeless and experiencing the stress of a heart condition. This confirmed health condition is verified through elevated blood pressure/ hypertension and/or elevated cholesterol level/hypercholesterolemia. The release of cortisol hormones when a person is emotionally stressed may damage one’s arteries and lead to heart disease. These hormones can increase an individual’s blood pressure by causing one’s heart to beat faster and the arteries to narrow [26]. For a homeless person to show full and successful readiness for discharge from a transitional living center, the person must show stabilization or reduction in physiological measurements of blood pressure/ hypertension and/or cholesterol levels. Controlling high blood pressure and cholesterol can cut a person’s risk for experiencing heart disease or undergoing a heart attack or stroke [18]. Hypertension is defined when a person has a systolic blood pressure above 120 mm Hg and a diastolic blood pressure above 80 mm Hg [28]. A cholesterol level is considered elevated when levels exceed 240 mg/dL [28].
Being Ready for Discharge: Readiness means being prepared. Readiness for discharge means (a) attaining the right conditions and ensuring that the essential resources are in place to support the change process, (b) securing a clear vision and objectives for the intended change, and (c) achieving the motivation to engage in change and make it work [29]. Prochaska, et al. [29] identified five stages associated with change: (a) pre-contemplation-people at this stage usually have no intention of changing their behavior and typically deny that they have a problem, (b) contemplation-people start acknowledging that they have a problem and begin to think seriously about changing their behavior, (c) preparation-most people make preparation to change their behavior within the next month or so, (d) action-people make a constructive effort to change their behavior. For example, a person removes all the desserts or sweets from his/her house toward the goal of losing weight, and (e) maintenance-this occurs over time and is a critically important stage. Over time refers to the length of time spent by the homeless adults residing in the transitional living center.
Successful Transition: To be ready for discharge from a transition living center, the individual must have returned to a normal level of stress through self-management of their high blood pressure and self-perceived status of a safe, structured, and supportive living environment, which in turn, facilitates the reduction of stress to normal levels. Successful transitioning out of a state of homelessness and into mainstream society will occur only if all services and resources offered in the transitional living center meet the real needs of the homeless adults and their families. Resources must be used by the homeless adult member and their families as shown through their active use of services.
Failure to Transition: Failure of this process occurs when services and resources are unused and/or are inappropriate to meet the needs of the homeless adult member and his/her family. Failure may also occur when services are available and appropriate but not used.
Research Questions
Based on the purpose, background, and conceptual framework, three research questions were posed.
Research Question 1: How do homeless adult members perceive readiness for discharge when compared with a transitional living center criterion of readiness?
Research Question 2: How do homeless adult members perceive their readiness for discharge over time?
Research Question 3: What is a homeless adult member’s perception of stress and its relationship to his/her health condition with regard to readiness for discharge?
Operational Definitions/Key Terms
Being Homeless: Being homeless is defined as A person who lacks a fixed, regular, and adequate nighttime residence; and has a primary night time residency that is: 1) a supervised publicly or privately operated shelter designed to provide temporary living accommodations; 2) an institution that provides a temporary residence for individuals intended to be institutionalized; or, 3) a public or private place not designed for, or ordinarily used as, a regular sleeping accommodation for human beings [3]. For this study, the adult homeless person’s perception was assessed through a self-developed, self-description questionnaire that was obtained during an audio-recorded one-hour interview. Being a member of a homeless family has similar characteristics as defined for a homeless person. A homeless family consists of at least one adult and one minor child 18 or under, or a disabled child over the age of 18 who still requires parenting by an adult member.
Undergoing Severe Stress: Severe stress is defined as a response to emotional pressure suffered for a prolonged period over which an individual perceives he or she has no control [25]. Severe stress will be assessed through a score on a 10-item psychological instrument entitled the Perceived Stress Scale used for measuring the perception of stress [25]. A total score 13 or greater on the Perceived Stress Scale (PSS) is indicative of higher levels of stress; a total score of 12 or less is indicative of lower levels of stress [25].
Transitional Living Center: A transitional living center is a facility that provides residents with employment and financial counseling, education and training, parenting skills, and medical services that facilitates successful reentry into mainstream society. It is transitional in that it expects the adult members to actively participate in the counseling and medical services provided by the Center. Reentry includes (a) permanent housing for the family, (b) access to health care and active participation on part of the family members, and (c) outreach services to ensure full return and integration into mainstream society. The adult homeless member’s participation in outreach services will be assessed with a self-developed questionnaire administered face-to-face over a one-hour recorded interview.
Being Ready for Discharge: Readiness is defined as (a) a homeless adult’s successful management of two physiological measures, lower blood pressure and cholesterol levels, within an acceptable range as documented by a primary care physician, (b) full-time employment of 30 hours or more per week or attending school as a full-time student, and (c) maintaining a minimum wage employment for at least 6 consecutive months. Readiness will be assessed by the team members’ review of the resident’s record for documented blood pressure and/or cholesterol level readings, completion of life-skills training classes as documented in the resident’s record, and the resident’s responses about readiness for discharge through a one-hour recorded interview.
Limitations
This study included several limitations that are acknowledged:
· Limitation due to setting. The setting for this study was one of the 20 transitional living center/shelters in San Antonio, Texas. These other shelters did not provide the broad range of educational services such as wellness programs, financial planning, and parenting counseling, coupled with a policy that allowed families to remain up to 24 months. While it is possible that other shelters may have provided similar services, only one transitional living center was considered for this study and used. This limitation due to setting is acknowledged.
· Limitation due to access to study participants. The study was limited due to the number of residents living in the Center and their accessibility. During the time of this study, 37 homeless adults were residing in the Center. Gaining access to the residents was challenging at times due to several activities occurring simultaneously for the residents. Recruitment of residents for the study could only be achieved through my weekly visits to the medical clinic and attending the monthly residential meetings. The medical clinic was opened one-day per week with limited operational hours. In addition, residents were required to attend weekly classes that were held on the same day and time that the medical clinic was opened. This procedural limitation due to access to study participants was acknowledged.
Assumptions
This study assumed that:
· Study participants would continue to maintain their eligibility as residents in a transitional living center during the study’s data collection period.
· Adult homeless members’ attendance records to the various services offered at a transitional living center reflect regular, complete attendance for all educational and health services and that the member would attend each session for the full duration.
Review of Literature
Introduction
This study’s focus was residents’ perceived readiness for discharge from a transitional living center. This is a complex experience made even more so when an adult living in a center also lives with a serious health condition and who sees him/herself as the family wage earner. This complex, but common, profile links the phenomena of being homeless with being sick and undergoing the stress that is also common to a non-resident wage earner. I examined these factors as perceived by the adults presumably readying themselves for discharge. This comprehensive literature review spanned the 1900s and the years between 2000 and 2015 and included studies located in CINADL, ESCBO, ProQuest, and PubMed. I used the following key words: being homeless; having heart disease and being homeless; undergoing stress and being homeless; and showing readiness for discharge from the homeless persons’ perspective, and from the institutions’ perspectives. Selye’s [23] theory of stress and Cohen and Williamson’s Perceived Stress Scale [25] were part of this research.
Being Homeless
Being homeless means being unable to acquire and maintain consistent, safe, secure, and adequate housing or lacking a fixed, regular, and adequate nighttime residence [3]. The National Coalition for the Homeless [10] indicated the top five reasons for homelessness include (a) unemployment/loss of job, (b) inability to pay rent/mortgage, (c) physical/mental disabilities, (d) substance abuse/addiction, and (e) altered family relationships. Home foreclosure also contributes to being homeless, either due to the homeowner’s inability to pay his/her mortgage, or because renters are evicted due to property owners not paying the mortgage. Homeless people are at the greatest risk for illness and have higher death rates than the general population [30]. Alcohol and drug use are commonly associated with the experience of homelessness [31,32]. Fazel, et al. [31] and others cited the major reasons for homelessness are an interaction between individual and structural factors. Individual factors include poverty, family problems, and mental health and substance abuse problems, whereby the availability of low-cost or affordable housing is the key structural determinant to homelessness.
Toro, et al. [33] conducted a comparison study of two samples of homeless adults. One was a sample of homeless adults in Poland (n=200), and the other was a sample of homeless adults in the United States (n=219). The researchers recruited and interviewed homeless adults from various shelters located in the United States and Poland. The only difference in the sampling population was that the researchers recruited homeless adults from shelters and soup kitchens across the United States, whereby this was not the case in Poland. In Poland, there are limited soup kitchens. However, the study identified some similarities and several differences. In both countries, homeless adults were males with dependent children, dealing with out-of-home placements and experiencing high levels of physical health problems [33]. The differences recognized among the homeless adults in Poland were that homeless male adults were older, experienced longer episodes of homelessness, and reported less satisfaction after they sought help from supporters. On the other hand, in the United States, the homeless adult males were younger and experienced higher rates of physical and mental health conditions [33].
In the United States, people experiencing or at risk for homelessness are typically women with two children under the age of 5 [1]. Sixty-three percent of women who are homeless have experienced some kind of domestic violence as an adult [10]. When a battered woman decides to leave an abusive situation, she might not have anywhere else to go but the streets. It is much more difficult to find housing when there is a history of abuse [10] because of poor credit and rental and employment histories related to their abuse.
Homeless Families: Families with children are among the fastest growing segments of the homeless population [5,34,35]. The typical homeless parent is a young, unmarried mother with two or three children, who grew up in poverty and typically experienced or witnessed domestic violence at some point in her life, never completed high school, and in many cases dropped out of school because of pregnancy [5]. The typical fathers were aged 35 years old, high school graduates, and unmarried [5]. Children who experience homelessness have an increased risk for negative outcomes in several developmental areas, the most frequent being high rates of physical and mental health problems that may have an impact on their ability to learn [35,36]. Major characteristics associated with families experiencing homelessness include a lack of affordable housing, extreme poverty, and exposure to violence. Over 30% of America’s three million homeless people are members of families. For each homeless family, many more families are living at the edge of homelessness [34].
While numerous programs intend to mediate these and other risks by offering services to families experiencing homelessness, a plethora of research exists that addresses the ways in which psychosocial needs are being addressed in these existing programs [8,37]. Yet, while both homelessness and poverty among families continue to increase, programs designed to assist those families who require shelters have been reduced by 10% per year, or to less than 20 days on average living in a shelter. The Federal Homeless Emergency and Rapid Transition to Housing (HEARTH) Act of 2009 signaled a new shift in homelessness policy and shifted funding away from shelters and onsite supportive services to more rapid re-housing initiatives [34]. Even though the 2009 HEARTH Act represented one way of providing quick housing, studies have shown that homeless families require time and supportive services to rebuild their financial independence through education counseling and training in employment skills [6,38,39]. However, some programs, such as the Federal Aid to Families with Dependent Children (AFDC) Program, reportedly have been criticized for deficiencies in providing basic survival resources for poor families [40].
Perceptions of Being Homeless: Families experiencing homelessness face a number of risks associated to their psychosocial health and well-being [39]. Well-being is defined as a state of one’s satisfaction with material, social, and the human aspect of one’s life and can be measured both objectively and subjectively [41]. Men who are homeless experience pervasive psychological stressors that diminish their ability to cope and navigate life problems” [42]. As such, men have a tendency to avoid professional counseling to alleviate their stressors. Homeless mothers/women experience higher rates of major depression disorders compared with the general population [43]. Children living with a depressed parent have experienced poor medical and mental health, as well as poor educational outcomes [43]. Thomas, et al. [41] and others explored the meaning and experience of well-being in the everyday lives of 20 homeless participants. The study revealed that health contributed very little to homeless participants’ perception of well-being. Homeless people perceive that keeping safe, being positive and feeling good, connecting with others and the ability to participate in normal life activities were the key contributors to well-being [41]. Thusly, services that provide a homeless person with opportunities to experience social inclusion that cultivates a sense of community and cultural connections may improve the well-being of a homeless person. However, it is difficult to draw any conclusion on this study based on its small sample size.
Mental Illness and Homelessness: Mental illness is the third largest cause of homelessness for people who are single. One estimate is that between 20 to 25% of the homeless population have some type of mental disorder [10]. Homeless women comprise an important portion of the homeless population who encounter multiple life stressors including mental illness, substance abuse, and trauma [35]. Women who are homeless may experience difficulty gaining shelter and/or health care [13,35]. Homelessness among female veterans is a national concern, but few studies have been conducted to show the differences between women and male veterans [44]. The number of homeless youths in the United States has reached an all-time high, and this represents a growing social problem. Homeless youth are at-risk for experiencing a broad range of negative life-outcomes, such as school dropout, the development of mental health problems, use/abuse of illicit substances, suicidality, and even early mortality. Young children who experience homelessness are more likely to have developmental delays and experience physical and mental health problems when compared with children in stable housing [36,45].
Undergoing Severe Stress
Families experiencing homelessness are under considerable stress. Those living in temporary shelters are stressed due to having to adjust to being in places that are overcrowded, noisy, and lack privacy [46,47]. The state of homelessness increases the likelihood of families separating, thus compounding the stress. Social stressors include unemployment, unstable housing, and problems with family, friends, and/or significant others [48]. Physiological stressors faced by homeless children and adolescents include depression, post-traumatic stress disorder, anxiety, and substance abuse [49]. Being homeless is an unhealthy circumstance that promotes illness and reduces one’s well-being. Severe stress can trigger major health issues that are prevalent among the homeless [17,21]. Selye’s [23] research on stress is applicable here and well-documented. Two types of stress responses as described by Selye include the Local Adaptation (LAS) and General Adaptation Syndromes (GAS).
Local Adaptation Syndrome: The LAS is a short-term process. It provides a localized response to a specific stressor that can restore or return a person’s body to a state of homeostasis. For example, a person cuts his/her finger while picking up a piece of broken glass. The finger heals quickly using the body’s natural defenses for healing.
General Adaptation Syndrome: However, if the person’s body is compromised, such as being malnourished, undergoing physical pressure, or experiencing chronic fatigue, the entire body becomes mobilized by the GAS. The GAS is a physiologic response of the whole body to stress and it can take much longer in returning one’s body to a full state of homeostasis [24]. If the body cannot fight these stressors, a person can die.
Being Homeless with Heart Disease and Undergoing Stress
Cardiovascular disease is one of the leading causes of death and accounts for 75% of the deaths occurring in the United States [17,18].
Homeless adults are at a greater risk of developing heart disease and increased rates of mortality. In a study conducted over a 5-year period (1988-1993), in comparing the mortality rates among homeless adults living in Boston, results showed that heart disease and cancer were the leading causes of death in persons who were between the ages of 45 to 64 years old [50]. In a study conducted among 426 low socioeconomic community-dwelling citizens and 287 homeless males over a 15-year period in Philadelphia, researcher results indicated that the prevalence of smoking and hypertension among the homeless males was comparable with low socio-economic community-dwellers, and both groups were at risk of developing coronary artery disease [51].
Being Homeless with Hypertension
Homeless individuals have a higher rate of hypertension when compared to the general population [52]. It has been shown that therapeutic lifestyle changes have the potential to decrease the morbidity and mortality associated with hypertension, through such interventions as smoking cessation and nutrition classes, physical activity, and exercise; yet, therapeutic lifestyle changes may be difficult for homeless people to implement due to conflicting priorities [52]. Homeless people consider shelter as a key priority in life. In a study conducted with 14 homeless participants, the participants viewed therapeutic lifestyle changes as being too restrictive when it came to nutrition, exercise, and educational resources. In general, homeless people often have more difficulty implementing healthy lifestyle changes due to limited meal choices, poor access to exercise equipment, and being unable to access health-related educational resources [52].
A precursor to readiness for discharge is readiness to change. Readiness to change is defined as a commitment and motivation to make health-related, behavioral, or lifestyle changes [22]. Readiness is described as being prepared-having the right conditions and resources in place to support a change [29]. Core areas that focus on readiness include undergoing changes that can improve and build on an individual’s basic life-skills, such as education, financial counseling, and parenting skills. In a study conducted with 43 homeless adults (25 males, 16 females, and 2 transgendered individuals) with mental disorders, researchers found that after 18 months of being assigned to a transitional housing project, the “Majority” of the participants reported positive changes across multiple domains [53]. Key themes included (a) feeling secure and proud, (b) adjusting to living alone, and (c) developing meaningful activity. Maycock, et al. [8] identified two factors associated with moving out of homelessness and reentering society: access to and engagement in drug treatment services and participating in education and training.
Discharge/Termination Criteria: Data collected from 217 families participating in a Transitional Housing Program that provided well-designed services over a 2-year period to 560 individuals showed that program participants who successfully completed the Hawkeye Area Community Action Program (HACAP), achieved greater gains in income than those participants who did not complete the program [54]. Successful completion was also credited to a strong working relationship between the case manager and program participant [54].
Limited literature was available in the material reviewed for this study that addressed discharge criteria from a transitional housing program. However, termination criteria were well documented. The primary cause for participants not completing a program was due to participants’ noncompliance and/or rule violations [54,55]. Termination criteria included (a) bringing mood-altering substances onto the property; (b) coming onto the property under the influence; (c) bringing people who were not residents in the house without staff permission; (d) failing to adhere to curfew guidelines; (e) stealing, gambling; or participating in illegal activity; (f) damaging property belonging to the Center; (g) carrying out acts or threats of physical violence; (h) failing to maintain full-time employment or be enrolled in an educational program; and (i) failing to attend weekly classes (N. Bracken, personal communication, May 18, 2015).
Successful Transition: Kurtz, et al. [9] and others conducted a qualitative research design study that primarily involved interviewing 12 formerly runaway and homeless youths (3 males and 9 females). The research question explored in the study was “How do runaway and homeless adolescents navigate the troubled waters of the adolescence - leaving home prematurely; living in high-risk environments; and engaging in dangerous behaviors - to make successful, developmental transitions into young adulthood?” Based on their results, the researchers found that the runaways and homeless youth resolved their homelessness through help from others-family, friends, and professional helpers-and perceived such attributes as caring, trustworthiness, strong boundaries and holding youth accountable, concrete assistance, and counseling. These were considered the most important attributes in making a smooth transition into young adulthood. Other studies have shown that transition homes improve the chances for a successful reintegration into mainstream society for women recovering from additions and for ex-criminal offenders who were released from prison [35,55]. More than just a structured living environment, transition homes provide on-site support from a full-time staff and life-skills development including communication skills, job-related skills, and ways of coping with conflict resolution.
In a study conducted on criminal offenders who were released from prison after serving their term, Washington State implemented a program called the Reentry Housing Pilot Program (RHPP) that provided housing assistance to high-risk/high-need offenders leaving prison that did not have a place to live. This pilot program included five different counties located in the state of Washington. Findings from this pilot program, involving a total of 181 high-risk offenders/participants, revealed that the RHPP program was successful in reducing new convictions by 22% and readmission to prison for new crimes by 36%. Results of this study also revealed that long periods of homelessness increased the risk of recidivism two times the rate for new convictions and readmission to prison when compared to those participants in stable housing [55].
Successful Transitional Living Centers: Safe and secure housing is considered by individuals as the foundation for homeless people to prepare and actively engage in the process of reentry into society [22,44,55-57]. Housing interventions, inclusive of supportive services such as employment, parenting, and educational counseling may be effective in reducing the return of such high-risk behaviors as drug and substance abuse [55]. Successful transitional living centers can be most effective when they offer the following services: (a) safe, stable living conditions; (b) basic life skill-building, including consumer education and instruction in budgeting and parenting skills; (c) interpersonal skill-building, including enhancing young people’s abilities to establish positive relationships with peers and adults; (d) educational/vocational opportunities; (e) mental health care, to include counseling; and (f) physical health care, including routine physical examinations, health assessments, and emergency treatment.
However, documented cases of failure have occurred despite well-coordinated services and efforts toward successful reentry into society. New York’s Greenlight Project provided a 60-day reentry program to prisoners who were scheduled to be released from jail within one year. The Project provided such services as employment, education, health care access, and family counseling, with an emphasis on housing. However, one year after the release of the prisoners, participants recidivated at a higher rate than prisoners who had not participated in the project [58]. The cause of recidivism by these participants is still under examination questioning whether the increase in recidivism was due to the limited period for the reentry initiative or the lack of motivation by the participants to change their way of life [58].
Health Care Costs for the Homeless: According to the Interagency Council on the Homeless, President Obama’s Fiscal Year 2014 (FY 2014) Budget included a considerable funding commitment of $5.3 billion targeted for homeless assistance, a 21.1% increase over the previously enacted fiscal year budgets. Two such programs included the Health Care for the Homeless Program and Projects for Assistance in Transition from Homelessness. The Health Care for the Homeless Program is aimed at providing (a) primary health care and substance use treatment, (b) emergency care for homeless people who are referred to hospitals for in-patient care services, and/or (c) other health-related needs to assist homeless people who are experiencing difficulty in accessing health care. The Projects for Assistance in Transition from Homelessness Program provided financial assistance to states to support services for homeless individuals who have serious mental illness and substance abuse disorders. Operating both of these programs is costly. At (Table 1) is a breakdown of budget for the homeless by fiscal year. Summary Review of the literature revealed that homelessness is a growing concern and challenge in the United States [2,20]. While several studies discussed the magnitude of homelessness and the impact of unmet health care needs [1,10,20,47,59], a gap in literature for this study became apparent. The studies aforementioned included small to moderate sample sizes that only addressed housing issues and did not include physiological/health considerations. Based on this limited information or substantiated research, a need exists to address the ways in which those who are homeless perceive their health/medical condition as preparation for readiness for discharge or return into mainstream society. Methods Setting This study’s data were collected between April and June 2015 at a transitional living center (Center) that had been providing services and housing to homeless families for over 30 years in San Antonio, Texas. In the past, transitional housing locations were often referred to as halfway houses. This Center was characterized as an interfaith ministry whose goal was to help the homeless families become more self-sufficient toward independent living on their own. Transitional housing is defined as affordable, supportive residential quarters designed to provide housing and appropriate support services to persons who are homeless or on the brinks of becoming homeless. The Center required (a) its families to have custody of at least one minor child, equal to or under the age of 18, or a disabled child over the age of 18, who still require parenting by an adult; (b) the adults must complete criminal background checks; the head of the household must be working or attending school for at least 30 hours per week; (c) the family must meet with case managers regularly to establish short- and long-term goals; and (d) the adults must attend weekly life-skills classes on money management, parenting, and conflict resolution. When a family entered the Center, a case manager assessed the needs of the family to find programs that matched the family’s circumstances. Services provided through transitional housing facilities varied from substance abuse treatment to psychological assistance, job training, and domestic violence assistance. The assistance provided varied, but it was generally affordable. The only requirement of a homeless family residing in the Center was to pay$100 per month that went toward rent and utility services. The Center housed a maximum of 40 homeless families over a 2-year period who showed a commitment to gaining self-sufficiency. Residential members’ commitment was defined as adherence to all admission criteria, as well as agreement to attend weekly classes of the Center. The Center noted that it promoted the viability of the family as a whole. The average number living in a Center was 200. In 2011, 298 residents (93 adults and 205 children) lived there. During data collection, 117 residents lived in the Center (37 adults & 80 children; N. Bracken, personal communication, May 18, 2015).
The Center’s free health and dental clinics opened in August 2000 and were staffed by medical, dental, and dental residents under the supervision of medical and dental faculty from the University of Texas Health Science Center at San Antonio (UTHSCSA). The facility included two physical examination or treatment rooms in the medical clinic and two dental chairs in the dental clinic. The health clinic was open between 5:30 p.m. until 8:00 p.m. once per week. Five student-run free clinics were supervised and operated by UTHSCSA. However, out of the five clinics, the Center was the only facility that provided residential housing to homeless families.
Research Design
I used a mixed qualitative and quantitative descriptive design for this study. The qualitative portion focused on respondents’ description of their health status experience, over time, in the Center and their perception of readiness for discharge from the Center. I collected data during a one-on-one interview for one hour with each study volunteer. For a husband and wife team, only the major breadwinner for the family was interviewed. For the quantitative portion, all respondents were asked questions derived from a standardized data collection instrument to assess self-perceived stress. Furthermore, I conducted a retrospective chart review to examine changes in the participants’ cardiac health condition over the previous year.
Population and Sample
Thirty-seven families comprised the population of the Center in the spring of 2015. During the data collection period, I had access to 15 families. Of the 15 families, 9 families (60%) met my inclusion criteria that included at least one family member with a heart condition admitted between January 2012 and May 2015. Given the focus on readiness over time, I sorted the population into three groups of respondents: (a) those that met the inclusion criteria and were in their first 6 months at the Center-five families met this criteria; (b) those who were in the second 6 months at the Center-five families met this criteria; and (c) those who were in their third 6 months at the Center-five families met this criteria.
Sample Type and Number
From this population, this study’s final sample included six families-two families in the Center from less than 6 to12 months, two between 12 to 18 months, and two between 18 to 24 months for six out of the total population. Of the 15 families, 9 adult members (60%) were interviewed, 3 adult members were used for the pilot study, 6 adult members for the full study, and 3 adult members did not keep their scheduled appointment.
Inclusion Criteria: Participants included adult “Wage-Earner” members who were diagnosed with some form of cardiac disease, such as hypertension and/or hypercholesterolemia. All participants had resided in the Center during one of the three specified time periods and were educated at a junior level or higher in school education. I used a self-developed checklist to ensure that inclusion criteria of respondents were met (Appendix A).
Exclusion Criteria: I excluded any non-English-speaking and deaf respondents due to the unavailability of translation services or interpretive resources. I also excluded any volunteer participants who indicated they were unable to read at a fifth-grade level. The participants’ educational and reading level was determined at the time they completed the data collection questionnaire background information for adult family members.
Data Collection Instruments
The study’s data collection instruments included a Perceived Stress Scale (PSS), an interview protocol, and an instrument related to the retrospective chart data.
Perceived Stress Scale: The PSS was the most widely used psychological instrument for measuring the perception of stress [25]. The PSS was a 10-item, self-report questionnaire that measured a person’s evaluation of the stressfulness of situations in the past month of their lives (Appendix B). Items on the PSS were designed to tap the extent to which unpredictable, uncontrollable, and overloaded respondents found their lives to be [25].
Sample Items: Participants were asked these 10 questions during the interview process. During the one-hour interview, each of the study participants were offered the following guidance regarding the Likert rating on the PSS:
I have a couple of questions that deal with the level of stress you have experienced over this last month. I will ask you the questions and there is a scale with the following ratings. Zero (0) meaning that this level of stress never occurs; one (1) meaning that this level of stress almost never occurs; two (2) meaning that this level of stress occurs sometimes; three (3) meaning that this level of stress occurs fairly often; and four (4) meaning that this level of stress occurs very often. I only need you to address your level of stress that has occurred starting from last month until now (today).
Assessed were aspects of stress that included (a) actual environmental experiences; (b) subjective evaluations of the stressfulness of a situation; and (c) the affective, behavioral, or biological responses to environmental experiences or their subjective evaluations [25]. The PSS asked study participants about their feelings and thoughts that had occurred during the last month. Sample items on the scale included such questions as “In the last month, how often have you been upset because of something that happened unexpectedly?” “In the last month, how often have you felt nervous and stressed?”
Validity: “PSS scores were moderately related to responses on other measures of appraised stress, as well as measures to potential sources of stress as assessed by event frequency” [25]. The only available verification of validity of the instrument was provided verbally by Dr. Sheldon’s assistant (C. Detrick, personal communication. June 19, 2015), who indicated that the instrument achieved acceptable levels of validation.
Predictive Validity: The intent of predictive validity is to assess the operationalization ability to predict something will occur [25]. The PSS predicted both objective biological markers of stress and increased risk for disease among persons with higher perceived levels of stress.
Reliability: I used the coefficient alpha to assess reliability. The normal span of values ranged between .00 to +1.00; higher values reflected a higher internal consistency [60]. The reliability for the 10-Item PSS had a “Good internal consistency” with a coefficient alpha of .78 [25].
Scorability: PSS-10 scores were obtained by reversing the scores on the four positive items (e.g., 0=4, 1=3, 2=2, etc.) and then summing across all 10 items. Items 4, 5, 7, and 8 were the positively stated items. Scores ranged from 0 to 40; the higher the score, the greater the stress. A total score of 13 or higher is indicative of higher levels of stress, a score of 12 or less is indicative of lower levels of stress. The scoring of the PSS instrument was validated by Dr. Sheldon’s assistant (C. Detrick, personal communication. June 19, 2015). In 1983, Louis Harris and Associates collected data using the 10-item PSS on a large sample group of 2,387 respondents living in the United States [61]. These data provided mean stress scores (Table 2).
The PSS 10 items were easy to understand and the response alternatives were simple to grasp. In each case, respondents were asked how often they felt a certain way [25].
Utility: PSS took 15 minutes to complete and was reportedly appropriate for participants who can read at the fifth-grade level.
Cost: PSS was free and easily downloaded from the Internet. The cost to respondents was one hour of their time.
Interview Protocol/Self-Developed Questionnaire: The interview protocol included two data collection instruments. I developed the interview questions using the conceptual framework of my study. The first section, the Data Collection Instrument, Background Information for Adult Family Members, was designed to provide background and demographic information on the participant. Because I was interested in the cardiac/heart condition of a participant, this particular instrument was used to document specific information regarding that aspect of a participant’s medical history. I asked each question to the participant and documented responses with pencil and paper and recorded the information with an audiotape recorder.
The second instrument was the Data Collection Instrument, Interview with Adult Family Members (Appendix C). The purpose of this self-developed interview questionnaire was to document the participant’s perception regarding his/her readiness for discharge from a transitional living center. Sample items for the interview included such questions as
· How long have you been homeless? What were the circumstances that led you to become homeless?
· What was it like for you at the beginning of your time at the transitional living center? How do you feel about your current situation?
· What has changed for you over time regarding your cardiac physical health status?
Trustworthiness: Participants were provided an opportunity to review their transcripts for accuracy at least 2 weeks following their interview. I provided participants with a copy of their written transcript for their review. The participants reviewed and returned their transcripts on the same day.
Dependability: Dependability refers to evidence being consistent and stable [60]. Inter-rater or inter-coder agreement occurs when several observers, raters, or coders reviewed the same information [62]. I used two coders and trained them using my self-developed codebook. The codebook included 60 items. The inter-coder agreement was 70% or higher. All disagreements were discussed until there was at least a .70 consensus reached.
Scorability: Participants’ responses to the open-ended interview questions were recorded in narrative form and also coded. Each participant was assigned a numerical identifier (i.e., 1, 2, 3, etc.) and the paper copies of the interview protocol were color-coded to include the Informed Consent.
Utility: The open-ended interview data collection instrument took 45 minutes, allowing the participant time to answer each question thoroughly.
Cost: The cost to respondents was one hour of their time. I spent 20 hours per participant in interviewing, transcribing, and reviewing transcripts. The cost of the printed-paper copies was 64 cents per each color copy and the audiotape recorders were $49 each (two tape recorders were purchased). Procedures Access to Study Participants: Prior to approaching potential participants, I followed the following procedures. First, I held a preliminary face-to-face meeting with the Vice President of Programs at the Center on March 13, 2015 to check if the facility could be used for the study. I followed this up with a formal letter to that Vice President and access was granted on April 7, 2015. I requested access to review the files of residents and to identify those adult members who met the inclusion criteria for the study (Appendix D). I provided a Letter of Introduction to each resident at the residential family center meeting on April 25, May 28, and June 25, 2015 (Appendix E). Following the residential family center meeting, the participant and I set a date and time to meet. The study participants reviewed and signed the Informed Consent on their scheduled interview date (Appendix F). Finally, I held all interview sessions at the transitional living center in a room that separated the participant from other residents in the Center. Protection of Human Participants: My application received approval from the Fielding Graduate University (FGU) Institutional Review Board (IRB) in April 2015. Approval by the University of Texas Health Science Center at San Antonio was not required. Homeless adult members’ participation in the research study was not anonymous, due to participants being recruited openly following the monthly residential family center meeting. Those adult members who attended the meeting received a copy of my Letter of Introduction and heard my presentation about the study. All participants’ responses were kept confidential. I interviewed each adult family member individually. Participants were assigned a numerical identifier, and their interview questionnaire was color-coded for ease of access. During the interviewing process, participants were promised that their name would not be disclosed or identified in the study. As noted, participants would only be identified by their numerical identifier. Participants were informed that they were free to decline participation, or if they felt uncomfortable answering any question, they did not have to, and they could withdraw at any time without penalty. This information was reiterated prior to the Informed Consent being signed. The Informed Content was signed at the time of the participant’s one-on-one interview with me. All residents received a copy of their signed Informed Consent. I transcribed all of the interviews. After the audiotaped interviews were recorded and the semi-structured interviews concluded, I placed all of the data/information in a binder and transported them from the Center in my private vehicle to my home residence. Conduct of a Pilot Study: After approval to conduct the study by the FGU, I requested and received a list of demographics from the Director of Case Managers at the Center. The list included the total number of residents residing in the Center, by gender, and the total number of children. As noted, at the time of this pilot study, there were 37 families residing at the Center (36 females, 1 male, and 80 children). I also requested a breakdown for the length of time that each family member had been residing in the Center, as this information was not initially available. For purpose of the pilot study, three homeless adult members were selected covering three specified times (6, 18, & 24 months). I conducted the pilot study over 3 days (May 18, May 28, and June 1, 2015). I interviewed the adult family members once for one hour that provided adequate time to ask and receive answers on all of the interview protocol questions. All of the interviews were conducted in a private, secured area in the Center away from the other residents. The only individuals in the room during the interview were the participant and me. The room provided adequate spacing, seating, and lighting. The criteria of a data collection instrument were assessed during the pilot study and the results were reported under the section on Data Collection Instruments. The lessons learned from the pilot study included the following: Gaining Access to Participants: Gaining access to the participants was the most difficult part. At the beginning of this study, a change occurred in leadership among the Case Managers in the Center. Under this new leadership, I was only allowed to interview residents by appointments. I was not permitted to conduct any open recruitment, or be in the Center without the presence of a Case Manager when interviewing residents. The Case Manager was not present in the interview room, but accessible in the Center in case any issue developed with the resident. This issue was resolved after I met with the Vice President of Programs. The Vice President of Programs felt that my attendance to the residential family center meeting would alleviate the problems in gaining access to the residents. On May 28, 2015, I attended and presented at the Center. Four of the six residents immediately volunteered for the study with a confirmed date and time for us to meet for an interview. The two remaining participants were interviewed on June 25, 2015. Interview Protocol/Self-Developed Questionnaire: The one-hour face-to-face interview was adequate with each participant; individual interviews were completed between 40 to 45 minutes. The PSS, 10-item, self-report questionnaire was appropriate and only took 15 minutes to complete. I completed the face-to-face interview and PSS questionnaire with each participant within 60 minutes. I recommended no changes to my interview protocol for the full study. Data Management I transcribed the interviews by listening to the audiotape and creating a written transcript. Next, I cleaned the written transcript by listening to the audiotape twice more to confirm accuracy of my transcription. Using my conceptual framework and the transcript, I analyzed, parsed, and numbered each interview response for the participants’ description of how they perceived their readiness for discharge from the Center. Each statement was coded against my self-developed codebook (Appendix G). The parsed statements were color-coded and reflected the participants’ responses to each question. Each research question was coded with a specific color. The categories derived from my conceptual framework formed my three constructs of being homeless, undergoing severe stress, and being ready for discharge. Three major category schemes were developed: (a) the participant’s perception of readiness for discharge as it compared with the Center’s criteria, (b) the participant’s perception of readiness over time, and (c) the participant’s perception of stress as related to his/her heart condition. Data Analysis My plan was to analyze the data from the PSS using the Non-Parametric ANOVA Kruskal-Wallis Test to determine if there were any significant differences by the reduced length of time of the participants living in the Center. Based on the small sample size, I hypothesized that there would not be any significant differences between the participants’ responses to the PSS as they related to their length of time in the Center. The qualitative data were obtained from open-ended interview questions. I used thematic and content analysis to examine the qualitative components of the data. Findings, with Analysis, Interpretation, and Discussion Here, I begin with a discussion of the intended and final sample. Next, I present the findings from my data. Results of the data were captured using two methods. Quantitative data were analyzed from the PSS. Analysis of the PSS included participants’ responses to the 10-item stress scale in relation to the participants’ length of time at the transitional living center and their responses to the four items that were reversed in coding. Qualitative data were analyzed through a semi-structured, self-descriptive questionnaire and resident interviews and revealed three overarching constructs that formed my conceptual framework of (a) being homeless, (b) undergoing severe stress, and (c) being ready for discharge. Intended and Final Sample The intended and final sample for the full study was six participants-two residents from each specified timeframe (6, 18, and 24 months) who resided in the transitional living center. Thirty-seven families comprised the population in the Center. During the data collection period, 15 families were living there. Of the 15 families, 9 adult members (60%) met the inclusion criteria with a heart condition with either hypertension or an elevated cholesterol level who were admitted between January 2012 and May 2015. Three of the nine adult members were used for my pilot study. Six adult members were used for my full study. I had three other adult family members volunteer for the full study; however, they did not keep their scheduled appointment. Those adult members who volunteered to participate agreed upon a date and time for me to meet with them. Length of Time at Center: The six participants for the full study included (a) two residents who lived in the Center for less than 6 months, (b) two residents who lived in the Center between 12 to 18 months, and (c) two residents who lived there between 18 to 24 months. (Table 3) summarizes the length of time for each participant in the study. I had trouble in recruiting volunteers for the study despite weekly visits to the Center that included visits to the health clinic located in the Center, attendance at the monthly residential family center meetings, and support by the Vice President of Programs, Case Managers, and health clinic staff. This Center was restrictive with regard to families’ available time. Families were required to prepare and eat meals at a specified time as well as complete their daily chores and attend the mandatory weekly classes that occurred during the evening hours. The best time for me to meet with participants for this study occurred on Thursday evening between 5:30 p.m. to 9:00 p.m. Demographics: The mean age for the study group was 34, with an age range of 23 to 45. The educational level for the study group included one participant with a high school equivalent GED, two participants with a technical vocation, and three participants with some college education. A prerequisite for entry into the Center was that families had children. The average number of children for each participant in the study was two. Children’s ages ranged from 1 to 16. The marital status for the study group varied: Four participants were separated from their spouse, one was single, and one was widowed. Studies have identified that the typical homeless parent is a young, unmarried mother with two to three children under the age of 5, had never completed high school, and in most cases dropped out of high school due to pregnancy [5,35]. In this study, all of the participants were women who had graduated from high school, several participants had completed 2 to 3 years of college, and all were serving as the primary breadwinner for their family. Quantitative Findings In this section, I examined the data obtained from the PSS that addressed the participants’ level of stress (Appendix H). Each participant was asked the 10-item questionnaire from the PSS (Appendix B). Scoring of the PSS was obtained by reversing responses to the four positively stated items in questions number 4, 5, 7, and 8 and then summing across all scale items. As noted earlier, the Likert Scale for the reversed items would read 0 = 4; 1 = 3; 2 = 2; 3 = 1; 4 = 0). A total score of 13 or greater on the PSS was indicative of higher levels of stress; a total score of 12 or less was indicative of lower levels of stress. I used the non-parametric ANOVA Kruskal-Wallis Test to determine if there were any significant differences by the reduced length of time of the participants in the Center. There were no significant differences (p<=0.05). Interpretation and Discussion: Higher levels of stress were noted among residents who lived in the Center for less than 6 months, as well as those residents who lived in the Center over 18 months. Residents living in the Center over 12 months, yet less than 18 months, revealed lower levels of stress when compared to those less than 6 months and those over 18 months. It is a common assumption among health researchers that stressful life events are not, in and of themselves, sufficient causes of pathology and illness behavior [25]. However, prolonged periods of stressful events are assumed to increase the risk of disease if the event is considered as threatening or demanding, and the coping resources are insufficient to address the threat or demand [25]. The adult members in this study were faced with multiple internal and external stressors that triggered other mediating factors to their well-being such as a health condition of hypertension/high blood pressure. Here, three of the six participants had a confirmed diagnosis of high blood pressure/hypertension, and one had a confirmed diagnosis of high blood pressure and an elevated cholesterol level as documented through review of their medical record. Three of the new arrivals to the Center denied having any form of cardiac/heart disease, such as hypertension or high cholesterol; these individuals had lived there for less than 6 months. One of the three participants who denied any form of cardiac/heart disease indicated a recent diagnosis of arthritis. Even though arthritis was not one of the medical conditions associated with the inclusion criteria, the medical condition of arthritis, in itself, is a chronic disease and one of the leading causes of disability associated in old age [24]. The age of this specific participant was 32, and she was already inflicted with a chronic disease at this young age. The debilitating effects of arthritis can place an impact on an individual’s knees, hips, and spine and can limit an individual’s physical mobility. Lack of physical mobility, which may include limitations in exercising, can have a direct effect on an individual’s cardiovascular system that can lead to cardiac/heart disease due to a sedentary lifestyle because of the detrimental effects of immobility. This participant was included in the study based on possible future alterations or changes that could occur in the individual’s health if a strict medical health regime was not implemented early on to ensure full physical mobility. Stress is an important mediator that can link stressful events to poorer health and health practices. All participants experienced various levels of stress as based on their PSS scores. Factors that can affect blood pressure include race, social environment, and emotional distress [63]. It was suggestive only to associate the participants’ state of being homeless, their current environment, and/or their perceived level of stress as contributing factors to their hypertension/high blood pressure. Qualitative Findings In this section, I examined and analyzed the respondents’ responses to the semi-structured, self-descriptive, open-ended interview questions. The three research questions analyzed were: Research Question 1: How do homeless adult members perceive readiness for discharge when compared with a transitional living center criterion of readiness? Research Question 2: How do homeless adult members perceive their readiness for discharge over time? Research Question 3: What is a homeless adult member’s perception of stress and its relationship to his/her health condition with regard to readiness for discharge? Perceived Readiness for Discharge Compared with the Center’s Criteria The Center’s criteria for residents’ readiness for discharge was based on participants’ successful completion of the 2-year program. Participants were required to save 30% of their monthly earnings as a form of financial security; to attend weekly classes, and to be gainfully employed. The Center provided several services to facilitate the residents toward transition out of their state of homelessness. However, the Center placed the responsibility on the resident. When participants were queried regarding the Center’s discharge criteria, they indicated that they were unaware of them. In comparison, they considered themselves ready for discharge when they compared the 2-year program. In this regard, while the respondents focused on one set of criteria, the Center focused on another. For the resident, being ready for discharge meant having a job, being free from debt, and securing a place to live. However, the two participants who lived in the Center for less than 6 months were more focused on getting settled and feeling secure in the Center. One participant shared two major goals that she wanted accomplished prior to her discharge/transition from the Center: One was to divorce her husband and the other was to buy a home. She noted, “I do not want to live in Section 8 housing or an apartment.” Three participants expressed concern regarding their ability to afford health insurance when they transitioned. One with health insurance had 7 months remaining in the Center before her scheduled discharge. All respondents’ perceptions regarding readiness for discharge were focused on their current state of homelessness and having a place to live. They openly shared the circumstances that led to their state of homelessness. They identified with one of the top five reasons for becoming homeless: (a) unemployment/loss of job, (b) inability to pay their rent/mortgage, (c) physical/mental disabilities, (d) substance abuse/addiction, or (e) family relationships. One respondent shared that she had been abandoned by her spouse, leaving her and their children with no money. Two of the respondents had been in abusive relationships and indicated that “They had nowhere to go”; these respondents lacked any type of family support. The emotions revealed by participants were strong and their perceptions of homelessness came across in many forms. Respondents expressed how it felt being homeless with such statements as (a) “I am very sad,” (b) “I am angry,” and (c) “I was lost.” Several respondents’ facial expressions of sadness were quite evident during the interview. Interpretation and Discussion: In the Center, security meant having 30% of a resident’s budget saved every month to ensure the availability of funds toward moving into housing upon discharge/transition from the Center. In order to have these funds, individuals must be working. Two of the participants indicated that they were looking forward to changing their current employment. For example, H.Z. indicated that she had 33 hours of prerequisites completed toward entering a nursing program and was eager to make the transition. Her only concern was having enough time remaining in the Center to complete her education. L.S. indicated that she was returning to school in the fall to become a medical secretary. She indicated that she had been a certified nursing assistant when she was 19 years old and enjoyed taking care of people. However, she stated she hurt her back and could no longer work in that role. She had one year remaining at the Center and was looking for some type of employment where she could afford health insurance. The Center required residents to work or be enrolled in school for at least 30 hours a week. Residents had the opportunity to switch jobs and/or enroll in school at their own discretion. The question remaining was “Is there enough time for a resident to save and secure funds for housing and be able to afford health insurance for their family with only 12 months remaining in a transitional living center?” (Table 4) summarizes the discharge criteria for the Center and respondents’ perception. Participant’s Readiness for Discharge Over Time Participants had lived in some type of temporary shelter prior to being approved for residency at the transitional living center. When the participants were asked how they perceived their readiness for discharge over time, the following quotes were made by the participants: · I now have a place to live. I know I must stay here for the full time (two years) at the Transitional Living and Learning Center and I am okay with this (L. S.). · It has been fun. They have been helping me. I haven’t and didn’t know all the help that is out here (F.V.). · I am not used to it yet. I am used to living my own life, having my own apartment, being on my own. I am not used to having others pay my bills (S.T.). · I feel like, I do not even know the words - I feel secure here (F.V.). · I have a place to live; a place for my son to sleep. I am trying to be as normal as possible (L.S.). Interpretation and Discussion: These responses were consistent with those found in the residents’ responses. Studies showed that individuals living in transitional housing have reported positive outcomes across multiple domains [53]. Some key themes included (a) feeling secure and proud, (b) adjusting to living alone, and (c) developing meaningful activity. Table 4 showed that Resident 4 was ready for discharge. Participants’ perception of stress as it relates to heart condition. When participants were asked how they perceived their level of stress in relation to their heart condition, such as hypertension following discharge from the Center, two of the six participants openly expressed concern based on lack of health insurance. Chronic diseases or illnesses and stress may cause someone to lose work and not have the financial means to support his or her family [25,64]. Three Participants had a History of Hypertension: Two had a confirmed diagnosis of hypertension prior to entry into the Center; one had hypertension for 4 years and the other over 13 years. The one specific participant with hypertension for 13 years was diagnosed with this heart condition in 2002. In 2013, this participant’s highest blood pressure reading was recorded at 190 over 110; this is a serious case of hypertension. This resident entered the Center in the summer of 2013. This participant’s blood pressure, at the time of data collection, was 138 over 78 on the date of our interview - a considerable improvement. This finding may suggest one effective outcome of the Center’s program. A primary criterion in my conceptual framework regarding successful discharge from the Center was a decrease in participants’ blood pressure readings. This specific participant was scheduled to transition from the Center within a few weeks of my interview. However, she said she was worried as she knew she would be unable to receive health care in the clinic after discharge due to her lack of health insurance. The aftercare services do not provide medical coverage. Another participant experienced both hypertension and an elevated cholesterol level; both of these heart conditions were long-standing and were being controlled with medication. At the time of my interview, this participant had a blood pressure reading of 119 over 73 and a cholesterol level of 199. Both of these readings were considered normal and suggests an effective result of the Center’s interventions. Another area of concern or stress involved the participants’ desire to change jobs or start formal schooling with less than 12 months remaining in the Center. For people experiencing homelessness, a stable source of income and opportunities to build assets are necessary for securing and maintaining housing [3]. Security is a feeling of certainty that everything is all right and that all of one’s basic needs are met. Maslow’s hierarchy of needs suggests that safety and security must be achieved prior to meeting love and belonging [24]. Interpretation and Discussion: Homeless mothers/women experience higher rates of major depression disorders compared with the general population [43]. It was evident during the interview that all of the women had experienced some form of depression. A respondent expressed being sad and having no family support. This particular respondent had experienced loss of family support on several levels. She had been married for only 3 days when her spouse was arrested, jailed, and later deported. Once she was no longer with her husband, she moved back home with her biological father and stepmother. The respondent shared that she and her stepmother did not get along, and the participant was asked to leave that home. Finally, the respondent indicated that she had located and made contact with her biological mother. This respondent lived with her biological mother for one week and then left due to her biological mother’s alcoholism. Homeless people feel displaced, sad, angry, alone, and hopeless. Many of the women who participated in this study expressed all of those emotions. These respondents’ emotional accounts were consistent with those found in the literature [8,39,64]. Women are at a greater risk for homelessness due to the need to escape physical and mental abuse and domestic violence in their household. A participant shared that she had to abandon her abusive relationship, and this was how she became homeless. The respondent stated, “I have been homeless for one month. My husband was abusive to me and my children.” This participant was not working and had three children ages 1, 2, and 8 years old. This respondent was indeed living in a stressful situation, yet her blood pressure was within the normal range (below 120 mm Hg and below 80 mm Hg). Stressful events may increase the risk or threat of a disease when coping resources are insufficient to address the threat [25]. This participant’s entry into the Center was timely based on her stressful situation. Summary Concerning the three research questions, the residents’ perceived readiness for discharge were incongruent with the Center’s criteria. The Center focused on the residents completing a 2-year program, being financially secure, and gainfully employed or in school as key factors toward being ready for discharge, while the respondents’ major foci were being safe and secure. Residents over time experienced higher levels of stress when approaching completion of the 2-year program. Residents’ perceived feeling secure, having order and structure in their lives, and obtaining housing upon discharge as their priority. Residents valued the importance of having good health; however, it was not perceived as a key contributing factor toward discharge from the Center. Summary, Conclusions, and Recommendations Summary The purpose of this descriptive study was to examine the perception of readiness for discharge and return to mainstream society after being homeless and residing in a transitional living center (Center) among selected adult members of homeless families. The selected members in this study were diagnosed with a cardiac/heart condition that included a medical condition such as high blood pressure (readings greater than 120/80 mm Hg), and/or elevated cholesterol levels (level higher than 240 mg/dL). The conceptual framework was developed around three major constructs: (a) being homeless, (b) undergoing severe stress, and (c) being ready for discharge from a transitional living center. The final sample for this study included six participants who had resided in the Center during the following timeframe: Two participants resided there for less than 6 months, two participants resided there between 12 to 17 months, and two participants resided there between 18 to 24 months. Even though participants lived in the Center during the three specified periods of time, a missed opportunity existed for interviewing residents who resided at the Center between 6 to 12 months; I did not have any participants volunteer to participate in the study during that timeframe. Homeless people are in a dismal situation when faced with finding employment, affordable housing, and access to health care. Family homelessness is one of the fastest growing segments of the homeless population. In America, more than 1.6 million children or one in 45 are homeless annually. In 2013, there were 30,000 people who were classified as homeless living in Texas. In the city of San Antonio where my study was conducted, 30% of the homeless were classified as families. San Antonio had 20 shelters available for homeless people at the time of data collection. However, these shelters only provided short-stay living accommodations, ranging from one day to a week, for homeless individuals or families. The Center where my study was conducted was the only facility in San Antonio that allowed families to reside up to 24 months and that is why I selected that facility. The preconceived idea that the typical homeless parent is a young, unmarried mother with two or three children, who had never completed high school, and may have dropped out of school because of pregnancy is not necessarily the case based on the outcome of this study. In this study, the mothers were mature adults, served as the primary breadwinner of their family, well-educated, and gainfully employed with a career-oriented focus. The mean age of the women participating in this study was 34 years, and all were high school graduates with at least 2 to 3 years of college. However, all of the women were impacted by certain life-altering changes that caused overwhelming stress to their lives. Such life-changing stressors included either the death of spouse or family member, being divorced or separated, being fired from work, and/or experiencing some type of personal injury/illness. The biggest stressor conveyed by all of the participants was their goal of providing a safe and secure environment for their children. The PSS questionnaire showed that residents were more stressed in the early months and later months during their time in the Center when compared with the period between these two time periods. All the residents participated in the same weekly life-skill classes at the Center regardless of their length of time in the Center. An opportunity may exist to develop individualized programs for residents at various stages of their readiness for discharge while residing in a transitional living center. Due to the small sample size, it is debatable if the specific length of time in the Center was related to a measure of stress. However, a Harris Poll conducted in 1983 with 2,387 respondents showed that normal stress levels based on gender, age, and race were not reflective of homeless people with a medical condition [25]. The medical clinic that was open one day a week at the Center was visited by the adult members with their children. Health visits by the adult members in the Center were limited. Three of the six study participants had regular visits to the medical clinic due to their health condition of having high blood pressure. However, health services were not available to residents after they were discharged from the Center. Residents were required to seek health care outside the Center. It has been demonstrated that therapeutic lifestyle changes have the potential to decrease the morbidity and mortality associated with hypertension through such interventions as smoking cessation and nutrition classes, physical activity, and exercise. However, therapeutic lifestyle changes may be difficult for homeless people to implement due to conflicting priorities [52]. Homeless people perceived having shelter as a key priority. For the participants in this study, being secure, experiencing order and ensuring structure to their lives, and obtaining housing were their most important factors. With regard to the participants’ health condition, their level of stress due to their homelessness may have been a contributing factor to their high blood pressure, but their heart condition was not the cause of their homelessness. Conclusions Based on a review of findings, the following conclusions were made. The Center selected for this study provides a valued service to the residents living there. The Center has a well-designed 2-year plan to track residents’ progress; however, the plan is not resident centric in that the Center’s criteria for discharge (success) were not fully known to the respondents. Based on the thematic data, quantitative and qualitative, residents experienced and perceived increased levels of stress upon transitioning out of the Center. The PSS was chosen based on its simplicity for interpretation and adequately measured the degree of stress in the residents’ lives, yet there were limited questions regarding the health of the residents. It was surprising to find participants who were within 2 weeks of transitioning from the Center with higher levels of stress than those participants just entering the Center. In this regard, the Center appears in need of individualized plans to address the varied and specific health requirements of residents. Based on this summary and conclusions, the following recommendations are offered. Recommendations · Replicate this study with a larger sample size including more participants in each of the varied, specified period of less than 6 months, 6 to 12 months, 13 to 18 months, and 18 to 24 months. · Create individualized plans in the transitional living center aimed at targeting residents who are just entering the program and a separate plan for residents who are at one year and beyond from discharge from the Center. · Design a Perceived Stress Scale with items appropriate for a vulnerable population, such as homeless persons, and develop measures to link ongoing assessments of stress with interventions used to address health and cardiac-related conditions. · Orient residents on entry into the transitional living center of the Center’s goals for successful transition. · Recommend a cut-off time for residents changing jobs or returning to school when there is less than 12 months remaining on their contract in the transitional living center. · Address aftercare services upfront to residents to ensure that the physical, emotional, social, and environmental needs are met by the resident prior to discharge. · Examine community approaches to post-discharge health care. Appendixes (A-H) Appendix A Data Collection Instrument Background Information for Adult Family Members Purpose: The purpose of this document is to provide background about the adult family members who were selected as part of this study. Instructions: Please provide an answer to items 1.1., and 1.2. For the remaining items, please insert a check mark (√) in the space provided. Leave no blanks. Please return this form with your signed copy of the Information Consent document. Scoring: Obviously, there is no right or wrong answer to any of the items. Part 1: 1.1. Age _________; 1.2. Sex: Male ________; Female ________ 1.3. Heart Disease (check mark -√) (Yes or No) Hypertension: Yes: ______ No: ______ (High blood pressure) Length of time I have had hypertension: Years: ____ Months: ____ High cholesterol level: Yes: ______ No: ______ Length of time I have had a high cholesterol level: Years: _____ Months: ______ 3. Race/ethnicity (check mark - √) American Indian or Alaska Native _____ Hawaiian or Another Pacific Islander _____ Asian or Asian American ______ Black or African American _____ Hispanic or Latino ______ Non-Hispanic White _____ Other _________ (please specify) 1.4. Marital status (check mark - √) Married ______ Divorced ______ Widowed _____ Separated _______ Never been married ______ Other ________ (please specify) 1.5. Current job situation: Right now, I am working at a job for wages: Yes: _______ No: _______ I work as (identify job type): _________________________ I work (number of hours per week): ____________________ I have worked at this current job for: Weeks: ________ Months: ______ 1.6. Educational level (check mark - √) Never attended school _______ Attended Grades 1 through 8 (Elementary) ________ Attended Grades 9 through 11 (Some High School) ______ Attended Grades 12 or GED (High School Graduate) ______ Attended College 1 to 3 years (Some College or Technical School) _____ Attended 4 years of College or more ________ Thank You for Completing This First Part of the Study! Appendix B Data Collection Instrument Perceived Stress Scale Perceived Stress Scale Purpose: The purpose of this Perceived Stress Scale Data Collection Instrument is to elicit information from homeless adult members regarding their feelings, thoughts and stressors during the last month. Confidentiality Agreement: By signing the Informed Consent document and by participating in this interview, you indicate your willingness to participate in this study and understand the agreement concerning confidentiality. Instructions: There is no right or wrong answers. Your thoughtful and full responses to the questions are appreciated. This scale asks you about your feelings, thoughts, and stressors during the last month. I will ask you each of the questions, and then I will indicate your response by circling how often you felt or thought a certain way. Perceived Stress Scale 0=Never 1=Almost Never 2=Sometimes 3=Fairly Often 4=Very Often 1 In the last month, how often have you been upset because of something that happened unexpectedly? 0 1 2 3 4 2 In the last month, how often have you felt you were unable to control the important things in your life? 0 1 2 3 4 3 In the last month, how often have your felt nervous and “stressed”? 0 1 2 3 4 4 In the last month, how often have your felt confident about your ability to handle your personal problems? 0 1 2 3 4 5 In the last month, how often have you found that things were going your way? 0 1 2 3 4 6 In the last month, how often have your found that you could not cope with all the things that you had to do? 0 1 2 3 4 7 In the last month, how often have you been able to control irritations in your life? 0 1 2 3 4 8 In the last month, how often have your felt that you were not on top of things? 0 1 2 3 4 9 In the last month, how often have you been angered because of things that were outside of your control? 0 1 2 3 4 10 In the last month, how often have you felt difficulties were piling up so high that you could not overcome them? 0 1 2 3 4 Format of Interview: 1.Face to face _____ 2.Go To Meeting____ 3.Telephone_______ 4.Skype________ 5.Focus group__ ___ Respondent does; do not___; request a summary of the study. Start time: ______ End time:________ Total time:_______(In minutes) Appendix C Data Collection Instrument Interview with Adult Family Members Purpose: The purpose of this interview protocol is to document adult members’ perception with regard to their readiness for discharge from a transitional living and learning center. Confidentiality Agreement: By signing the Informed Consent document and by participating in this interview, you indicate your willingness to participate in this study and understand the agreement concerning confidentiality. Instructions: Over the next one hour, I invite you to share your perceptions. I am interested in learning how you see yourself being ready for discharge from this Center. Scoring: There is no right or wrong answers. Your thoughtful and full responses to the questions are appreciated. Part 1: Background Information (completed by participant) Part 2: Interview Items Open-Ended Questions: Being Homeless RQ 2.1: How long have you been homeless? How did this happen? What circumstances have contributed to being homeless? What is this like for you? What is it like for your __________ (insert each member name)? RQ 2.2: So, what was it like for you during the beginning (first six months)? · People during the 1st six months at the transitional living center · People during the 6th until 18th month at the transitional living center · People during the 18th until 24th month at the transitional living center · So, what was it like for other members in your family? · During their first six months? RQ 2.3. Since your time in the Center, have your feelings changed? When? How? So, after all this time, do you feel ready for discharge? If so, what got you there? If not, what happened - what prevented this from happening? Open-Ended Questions: Undergoing Severe Stress RQ 2.4: What is the adult members’ perception of stress? (This questionnaire will be given at the start of the interviewing process - when I first meet with the family member). · 10-Item Questionnaire from the Perceived Stress Scale RQ 2.5: Has being here been tough on you? How so, please describe. What services at the transitional center are being provided to you? What services at the transitional center are you using? How have you managed your heart condition while being here? How so, please describe. How have you managed your high blood pressure while being here? How so, please describe. How have you managed your high cholesterol level while being here? How so, please describe. Open-Ended Questions: Readiness for Discharge RQ 2.6: Since being here, have you seen a change in your blood pressure readings? If so, is your blood pressure readings the same; or lower or higher? Since being here, have you seen a change in your cholesterol levels? If so, is your cholesterol level the same; or lower or higher? How have the services that were provided at the transitional center assisted you? What stressors do you feel that you have resolved? What stressors still exist for you? How do you perceive that you will cope with those existing stressors? How does the transitional center determine that you are ready for discharge? What do you think of these criteria for determining if you are ready for discharge? How do you perceive yourself as ready for discharge from the transitional center? So, how do you stand when thinking about these criteria items for discharge from the Center? Appendix D Letter to Vice President of Programs, San Antonio Metropolitan Ministries, Inc. Spring 2015 Ms. Anna Vidaurri Vice President of Programs San Antonio Metropolitan Ministries, Inc. 5454 Blanco Road San Antonio, TX 78216 Dear Ms. Vidaurri: I am currently a doctoral student completing my dissertation at Fielding Graduate University located in Santa Barbara, California. My research study is entitled, Health Factor Readiness to Successful Reentry Among a Sample Group of Homeless Families Return to the Mainstream Society. I would like to conduct my study among a group of adult family members residing at a Transitional Living and Learning Center. The adult family members selected for this study must have a documented health history of heart disease. The heart disease health condition may include adult family members identified with either high blood pressure, diagnosed with coronary heart disease, being overweight, and/or having an elevated blood cholesterol level. Upon approval by the Institutional Review Board (IRB) of Fielding Graduate University, I would like to start my data collection during the month of April 2015. My goal is to complete my data collection by mid-May 2015. Attached is a Letter of Introduction for the families residing at the SAMM Transitional Living and Learning Center to participant in this research study. Request that a copy of this Letter of Introduction be provided to each family during your monthly residential meeting. I will require between 9 to 15 research participants for my study. Three family members will be used as part of my Pilot Study. The remaining number of participants will serve as my sample group of families for my dissertation. I only require one adult member per family to meet my inclusion criteria. I am most interested in the family member that meets my inclusion criteria who is the “Wage-earner or bread-winner” for the family. This research study will require one hour of the participant’s time. I will conduct a one-on-one interview, gaining approval by the selected family member to audio/tape record his/her responses to my interview questions. Those adult family members identified who meet the inclusion criteria and selected for this study will be contacted by me. I will coordinate a date and time to conduct the individual interviews with the selected participants. All interviews will occur at the Transitional Living and Learning Center in a secured and protected area. Adult family member’s participation in this research is confidential. Their participation will not be anonymous; however, their responses will not be attached to them. In the written dissertation, no respondent will be identified by name. Participants’ are free to decline participation or if they do agree they can redraw at any time without penalty. If they choose to be a part of this study, I will provide each adult family member with an informed consent form which will require their signature. Enclosed is a copy of the Informed Consent Form. If you have any questions, please do not hesitate in contacting me at (XXX) XXX-XXXX. I greatly appreciate your time and opportunity to conduct my research study at your facility. Sincerely, Lark A. Ford, MA, MSN, RN Doctoral Student Fielding Graduate University Appendix E Informed Consent for Homeless Adult Family Members Summer 2015 Dear Study Participant (Insert Name): I am writing to you to request your participation in a research study I am conducting as a doctoral student at the Fielding Graduate University School of Human and Organizational Development, Santa Barbara, California. This mixed, part descriptive, part quantitative study focuses on your views of being ready for discharge from a transitional living and learning center. The study involves you for one session for one hour. During the hour, I will talk with you about your situation and your time at the Center and your views about your health. The Institutional Review Board of Fielding Graduate University retains access to signed informed consent forms. The information that you provide will be kept strictly confidential. Your responses will be kept confidential as they will not be attached to any name. While others may know that you are participating in this study, no will know what you say. You will be assigned a number that I will use to track any quotes that might be included in the final research study. You will have the opportunity to review the typed notes of your responses and make corrections, additions or subtractions. No one will know what responses may be attributed to you. I will be the only person conducting the interview with you and recording your responses. So what you say will be confidential. All the related research materials and any documentation related to this study will be kept in a secure file cabinet and available only to me as the principal investigator. I will destroy the files after three years after the completion of the study. The results of this research will be published in academic journals, books, or papers. I hope that you consider this an important study and view your contribution as a positive one to the advancement of research in this field. I believe that the risks to you are minimal; there is only a small chance that you may experience some uneasiness in sharing the circumstances that brought you here to the transitional living and learning center. At any time during my interview, if you feel uncomfortable, please do not hesitate in letting me know. You may withdraw from this study at any time without negative consequences. Should you withdraw, your data will be destroyed and eliminated from the study. This study is voluntary and there is no obligation to participate. There is no financial remuneration for participating in this study. You may request a copy of the study’s summary by indicating your interest on this form. If you have questions at any time, you may contact me by phone at XXX-XXX-XXXX, or by email at [email protected] Two copies of this Informed Consent form have been provided. Please sign both, indicating that you read, understood, and agreed to participate in this research. Return one copy to me and keep the other one. The Institutional Review Board of the Fielding Graduate University retains access to signed informed consent forms. ______________________________________________________________________ Name of Participant (please print) Telephone Number _________________________________ Signature of Participant Date __________________________________ _____________________ Yes, please send a summary of the study results to me at: ___________________________________________ Street Address City, State, Zip THANK YOU FOR COMPLETING THIS FIRST PART OF YOUR PARTICIPATION IN THIS STUDY!! Appendix F Letter of Introduction Dear Resident of the SAMM Transitional Living and Learning Center, I am a doctoral student at Fielding Graduate University located in Santa Barbara, California and I would like to invite you to participant in research study that I am conducting at a Transitional Living and Learning Center between April and June, 2015. My research study is evaluating how you perceive your health readiness toward discharge from a Transitional Living and Learning Center. Research studies are done to answer a question. I have several questions that I will ask you. In addition, I would like to tape record your responses so that I can capture all of your responses. The time commitment for this study will require one hour of your time during the interview process. All interviews will occur at a Transitional Living and Learning Center in a secured and protected area. Adult family member’s participation in this research is confidential. In my written dissertation, you will not be identified by name. You are free to decline at any time during this study without penalty. The reason that I want to know about your health readiness toward discharge from the Transitional Living and Learning Center is based on the lack of research studies that have addressed this matter. An individual’s health and well-being are very important. Poor health can reduce the quality of life of among individuals, as well as increases the risks for many other serious chronic diseases and premature deaths, such as coronary artery disease. Taking part in the research study is voluntary. I am looking for participants with the following known health condition: Diagnosed with a heart condition, such as coronary artery disease (pain in your chest when exercising or walking upstairs that goes away with rest) High blood pressure of 120/80 or higher High cholesterol level of 240 or higher If you are interested in participating in this research study, please contact me by April 30th, 2015 at the following number: (XXX) XXX-XXXX - please leave your name and telephone number so that I may return your call or E-mail: [email protected] Sincerely Lark A. Ford, MA, MSN, RN Doctoral Student Fielding Graduate University Appendix G Homeless Families Return to Mainstream Society Code Book© Lark A. Ford, MA, MSN, RN Interview Protocol CODE Age 18-29 30-44 45-54 55-64 65 & older 1.1 1.2 1.3 1.4 1.5 Sex Male Female 2.1 2.2 Heart Disease Hypertension Elevated Cholesterol Length of time with high blood pressure (write out) Length of time with elevated cholesterol (write out) 3.1 3.2 3.3 3.4 Race/Ethnicity American Indian or Alaska Native Hawaiian or Pacific Islander Asian or Asian American Black or African American Hispanic or Latino Non-Hispanic White Other 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Marital Status Married Divorced Widowed Separated Never been married Other 5 5.1 5.2 5.3 5.4 5.5 5.6 Current Job Spelled-out Educational Level Attended Grades 1 through 8 (Elementary) Attended Grades 9 through 11 (Some High School) Attended Grades 12 or GED (High School Graduate) Attended College 1 to 3 years (Some College or Technical School) Attended 4 years of College or more 7.1 7.2 7.3 7.4 7.5 RQ1: How do homeless adult members perceive readiness for discharge when compared with a transitional living center criterion of readiness? Probe questions: How long have you been homeless? How did this happen? What circumstances have contributed to you being homeless? What is it like for you? What is it like for your family members? 8.1 8.2 8.3 8.4 8.5 RQ2: How do homeless adult members perceive their readiness for discharge overtime? Probe questions: So, what was it like for you during the beginning? People during the 1st six months at the transitional living center. People during the 6th until 18th month in the transitional living center. People during the 18th until 24th month in the transitional living center. So, what was it like for other members in your family? Then how did these feelings, ideas change overtime? When? How? 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 RQ 3: What is a homeless adults members’ perception of stress and its relationship to his/her health condition with regard to readiness for discharge? Probe questions: Has being here in the Center been tough on you? How - describe? How have the services that were provided at the transitional center assisted you? How have you managed your high blood pressure? Have you noticed a change in your blood pressure? When? How? How have you managed your high cholesterol level? Have you noticed a change in your cholesterol level? When? How? What stressors do you feel that you have resolved? What stressors still exist for you? How does the transitional center determine that you are ready for discharge? What do you think of these criteria for determining if you are ready for discharge? So, how do you stand when thinking about the criteria for discharge from the transitional center? 10.1 10.2 10.3 10.4 10.5 10.6 10.7 10.8 10.9 10.1 10.11 10.12 10.13 10.14 10.15 10.16 Appendix H Shelter/Perceived Stress Study Kruskal-Wallis Non-Parametric Test for Differences in the Perceived Stress Score and Items by Reduced LOT in Center Ranks Reduced LOT in Center N Mean Rank pssc Perceived Stress Score - Computed 0 LT 6 Mo. 2 5 1 12 - 13 Mo. 2 2.5 2 17 - 24 Mo. 2 3 Total 6 Pss01 In the last month, how often have you been upset because of something that happened unexpectedly? 0 LT 6 Mo. 2 4 1 12 - 13 Mo. 2 4 2 17 - 24 Mo. 2 2.5 Total 6 Pss02 In the last month, how often have you felt that you were unable to control the important things in your life? 0 LT 6 Mo. 2 4.75 1 12 - 13 Mo. 2 2.5 2 17 - 24 Mo. 2 3.25 Total 6 Pss03 In the last month, how often have you felt nervous and stressed? 0 LT 6 Mo. 2 5.5 1 12 - 13 Mo. 2 2.75 2 17 - 24 Mo. 2 2.25 Total 6 Rpss04 Reversed: In the last month, how often have you felt confident about your ability to handle your personal problems? 0 LT 6 Mo. 2 5 1 12 - 13 Mo. 2 2.75 2 17 - 24 Mo. 2 2.75 Total 6 Rpss05 Reversed: In the last month, how often have you felt that things were going your way? 0 LT 6 Mo. 2 3.5 1 12 - 13 Mo. 2 3.5 2 17 - 24 Mo. 2 3.5 Total 6 Pss06 In the last month, how often have you found that you could not cope with all of the things that you had to do? 0 LT 6 Mo. 2 5 1 12 - 13 Mo. 2 2.75 2 17 - 24 Mo. 2 2.75 Total 6 Rpss07 Reversed: In the last month, how often have you been able to control irritations in your life? 0 LT 6 Mo. 2 4.5 1 12 - 13 Mo. 2 2.25 2 17 - 24 Mo. 2 3.75 Total 6 Rpss08 Reversed: In the last month, how often have you felt that you were on top of things? 0 LT 6 Mo. 2 3.75 1 12 - 13 Mo. 2 3 2 17 - 24 Mo. 2 3.75 Total 6 Pss09 in the last month, how often have you been angered because of things that were outside of your control? 0 LT 6 Mo. 2 5.5 1 12 - 13 Mo. 2 2.75 2 17 - 24 Mo. 2 2.25 Total 6 Pss10 in the last month, how often have you felt difficulties piling up so high that you could not overcome them? 0 LT 6 Mo. 2 4 1 12 - 13 Mo. 2 3.25 2 17 - 24 Mo. 2 3.25 Total 6 Test Statisticsa,b Chi-Square df Asymp. Sig. pssc 2.059 2 0.357 pss01 0.968 2 0.616 pss02 1.591 2 0.451 pss03 3.712 2 0.156 rpss04 2.25 2 0.325 rpss05 0 2 1 pss06 2.25 2 0.325 rpss07 1.591 2 0.451 rpss08 0.25 2 0.882 pss09 3.603 2 0.165 pss10 0.25 2 0.882 a. Kruskal Wallis Test; b. Grouping Variable: lotr Fiscal Year Budget ($) in Millions 2010 236 2011 280 2012 296 2014 384
Table 1: Budget for the Homeless and in Transition by Fiscal Year.
Category N M SD Gender Male 926 12.1 5.9 Female 1,406 13.7 6.6 Age 18-29 30-44 645 14.2 6.2 45-54 750 13 6.2 55-64 285 12.6 6.1 65 & older 282 11.9 6.9 296 12 6.3 Race White Hispanic Black 1,924 12.8 6.2 Other 98 14 6.9 76 14.7 7.2 Another minority 50 14.1 5 Note. L. Harris Poll information on 2,387 respondents in the United States [61].
Table 2: Norm Table for the Perceived Stress Scale 10-Item Inventory.
Length of Time (months) Frequency Percent Less than 6 2 33 12 1 16.7 13 1 16.7 17 1 16.7 24 1 16.7 Total 6 100
Table 3: Summary of the Length of Time in the Center for Each Participant.
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# What is the limit as x approaches infinity of sinx?
##### 1 Answer
Jun 6, 2015
The range of $y = \sin x$ is R = [-1;+1]; the function oscillates between -1 and +1. Therefore, the limit when $x$ approaches infinity is undefined.
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# Injury Polar Plots
Injury data has been a bit of a guilty pleasure for me recently. When browsing through some of the data from Transfermarkt I looked into different ways of visualizing it. Specifically I was focused on highlighting injury lengths and their distribution over a player’s career.
This resulted in the below viz for Marco Reus which is inspired by how I view the (European) football calendar: running counter-clockwise and with the summer break at 6 o’clock.
Each ring in the polar plot corresponds to one season moving from the first season on the inside to the most recent season as the outer ring. On the right half there is some space for a player portrait, some commentary and an overview on missed games per season.
### Form Over Function
Looking at the polar chart it is clear that it looks appealing (at least in my view), but it is hard to read. I do not think that it is hard to understand what is shown on a high level, but following individual seasons by ring or comparing injury durations across seasons is very hard. In other words it commits the cardinal sin of prioritizing form over function.
Even the CRAN documentation for the coord_polar function explicitly warns of this and they are not subtle about it:
NOTE: Use these plots with caution - polar coordinates has major perceptual problems. The main point of these examples is to demonstrate how these common plots can be described in the grammar. Use with EXTREME caution (from documentation of coord_polar {ggplot2}).
### Bar Chart Representation
A more conservative approach to representing this data is to use a bar chart. This choice addresses the two problems highlighted above but definitely reduces the visible appeal. See below for Holger Badstuber:
### How To Construct These Plots
Above visualizations are entirely produced in R without any manual steps. I will outline below how to replicate them with the example of Cristiano Ronaldo and we’ll start with loading the necessary libraries.
library(tidyverse) # ggplot and table manipulations
library(lubridate) # handling of date logic
library(cowplot) # plotting the player portrait
library(glue) # neccessary to style the title
library(ggtext) # neccessary to style the title
library(patchwork) # allows us to combine plots
library(kableExtra) # nice html table formatting
At the very top of this post you already see the kind of data that Transfermarkt provides for Cristiano Ronaldo. The next step is to bring them into a format that allows us keep healthy and injured periods separated.
We achieve this by adding a dummy column with unique names for each healthy or injured period. If we simply all call them healthy or injured ggplot will group them all together and we cannot keep the original order of dates.
The day_diff column measures the duration of each period and counts from August 1st for the first period of each season.
The dataframe we are feeding into ggplot now looks like the below. The code to produce this systematically is quite involved so I won’t spell it out here. Of course this can also produced manually.
injury season from to day_diff dummy color
Healthy 2002/2003 NA NA 334 Healthy_2002/2003 grey80
Summer_Break 2002/2003 NA NA 31 Summer_Break_2002/2003 grey10
Healthy 2003/2004 NA NA 334 Healthy_2003/2004 grey80
Summer_Break 2003/2004 NA NA 31 Summer_Break_2003/2004 grey10
Healthy 2004/2005 NA NA 334 Healthy_2004/2005 grey80
Summer_Break 2004/2005 NA NA 31 Summer_Break_2004/2005 grey10
In the following chunk we are now plotting our polar plot. The plot is initially based on a simple geom_bar function but is then transformed into a polar plot through coord_polar at the very end.
A few comments on the coord_polar parameters: start is quoted in radians and specifies where in the circle your chart should start. The choice of -1 for direction ensures that the charts plots counter-clockwise.
The code below also contains a little hack that allows us to insert some space at the very center of the circle. In scale_x_discrete we concatenate some dummy string variables to our actual season vector. We won’t see any data plotted there but can so control the minimum radius of our first season.
# Define order of data being plotted and extract a vector of seasons
data_plot$dummy <- factor(data_plot$dummy, levels = rev(data_plot\$dummy))
seasons <- data_plot %>% distinct(season) %>% pull(season)
# Most of the heavy lifting happens in the five lines below
plot <- ggplot(data_plot, aes(x = season, y = day_diff, fill = dummy)) +
geom_bar(width = 0.5, stat = "identity") +
scale_x_discrete(limits = c("dummy", "dummy", "dummy", "dummy", "dummy",
seasons,
"annotation")) +
scale_fill_manual(values = tibble::deframe(data_plot %>% select(dummy, color))) +
coord_polar(theta = "y", start = 6.5/6*pi, direction = -1)
# Followed by some annotations and cleaning up of the theme
plot <- plot +
annotate("text",
x = "annotation",
y = 331,
colour = text_col,
size = 2,
label = "June|",
angle = 340,
fontface = 2) +
annotate("text",
x = "annotation",
y = 5,
colour = text_col,
size = 2,
label = "|August",
angle = 20,
fontface = 2) +
theme_void() +
labs(title =
glue::glue("{player_name} - <b style = 'color:{highlight_col}'>Injury</b> History")) +
theme(panel.background = element_rect(fill = background_col, color = background_col)) +
theme(plot.background = element_rect(fill = background_col, color = background_col)) +
theme(plot.title = element_text(size = 14, color = text_col)) +
theme(legend.position = "none", plot.title = element_markdown(hjust = 0.5)) +
theme(axis.title.x = element_blank(),
axis.title.y = element_blank(),
axis.text.x = element_blank(),
axis.text.y = element_blank(),
axis.ticks.x = element_blank(),
axis.ticks.y = element_blank())
# Finally we are adding the label for each season
for(season in seasons){
plot <- plot +
annotate("text",
x = season,
y = 350,
colour = text_col,
size = 1.5,
label = paste0(substr(season, 3, 4), "/", substr(season, 8, 9)),
fontface = 2)
}
plot
Once we have our polar plot we can combine it some more background information: a player portrait, some commentary and another ggplot chart. To achieve this we make use of the patchwork-package. With the help of this elegant package combining these four elements is literally a one-liner:
plot + (img_plot / txt_plot / missed_plot).
img_plot <- ggplot() +
theme_void() +
theme(panel.background = element_rect(fill = background_col, color = background_col)) +
theme(plot.background = element_rect(fill = background_col, color = background_col)) +
xlim(0, 1) +
ylim(0, 1) +
draw_image(path_to_img, x = 0, y = 0.0, width = 1)
txt_plot <- ggplot() +
theme_void() +
theme(panel.background = element_rect(fill = background_col, color = background_col)) +
theme(plot.background = element_rect(fill = background_col, color = background_col)) +
xlim(0, 1) +
ylim(0, 1) +
annotate("text",
x = 0,
y = 1.0,
colour = text_col,
size = 2.5,
hjust = 0,
label = "-----------------------------------------------------------------") +
annotate("text",
x = 0,
y = 0.8,
colour = text_col,
size = 2.5,
hjust = 0,
label = "- Remarkably resilient to injuries over his long career") +
annotate("text",
x = 0,
y = 0.5,
colour = text_col,
size = 2.5,
hjust = 0,
label = "- Longest injury break during the season 2008/09 \n with a fractured kneecap") +
annotate("text",
x = 0,
y = 0.2,
colour = text_col,
size = 2.5,
hjust = 0,
label = "- Only missed more than five games in four of 18 seasons") +
annotate("text",
x = 0,
y = 0.0,
colour = text_col,
size = 2.5,
hjust = 0,
label = "-----------------------------------------------------------------")
plot + (img_plot / txt_plot / missed_plot)
As mentioned above already we can also show the same data in a more readable, but visually less appealing form. Essentially this is the state of the plot before it is bent into a circle shape.
plot_bar <- ggplot(data_plot, aes(x = season, y = day_diff, fill = dummy)) +
geom_col(width = 0.7) +
scale_x_discrete(limits = seasons) +
scale_fill_manual(values = tibble::deframe(data_plot %>% select(dummy, color))) +
coord_flip()
plot_bar <- plot_bar +
annotate("text",
x = "annotation",
y = 331,
colour = text_col,
size = 2,
label = "June|",
fontface = 2) +
annotate("text",
x = "annotation",
y = 5,
colour = text_col,
size = 2,
label = "|August",
fontface = 2) +
theme_void() +
labs(title = glue::glue("{player_name} - <b style = 'color:{highlight_col}'>Injury</b> History")) +
theme(panel.background = element_rect(fill = background_col, color = background_col)) +
theme(plot.background = element_rect(fill = background_col, color = background_col)) +
theme(plot.title = element_text(size = 14, color = text_col)) +
theme(legend.position = "none", plot.title = element_markdown(hjust = 0.5)) +
theme(axis.title.x = element_blank(),
axis.title.y = element_blank(),
axis.text.x = element_blank(),
axis.text.y = element_text(size = 6, color = text_col),
axis.ticks.x = element_blank(),
axis.ticks.y = element_blank())
plot_bar
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# Comment History for Banjo Paterson
The Forum > User Index > Banjo Paterson > Comment History
» 21/09/2019 7:57:35 AM . (Continued …) . Our conscious mind is produced by our brain and allows us to be aware.....
» 21/09/2019 7:55:16 AM . Dear Loudmouth, . You wrote : « If 3 % of Australians over 18 are either homosexual .....
» 20/09/2019 2:28:52 AM . Dear Not_Now.Soon, . You wrote : « How would you approach the topic as a whole, look.....
» 18/09/2019 9:55:04 PM . Dear Foxy, . Whether it be due to nature or nurture, the dividing line between male a.....
» 18/09/2019 7:45:14 AM . Dear Big Nana, . Thank you for that interesting post. I appreciate it. I’m sure ther.....
» 18/09/2019 7:28:31 AM . It's a pity you didn't write that, Not_Now.Soon. Unfortunately, I had to do it. ......
» 18/09/2019 7:25:01 AM . Dear Not_Now.Soon, . You wrote : The few homosexual couples I have known over the ye.....
» 18/09/2019 6:30:39 AM . Dear ALTRAV, . You wrote : 1. « … Mr Boeckman is entitled to his opinion, but I am r.....
» 17/09/2019 3:25:55 AM . Of course, that was intended for Not_Now.Soon. Soory about that. ......
» 17/09/2019 3:23:48 AM . Dear , . You wrote : 1. « Being gay isn't normal. Whether it should be accepted, tol.....
» 17/09/2019 12:41:32 AM . Dear ALTRAV, . You wrote : 1. « Your concept of normal is not in keeping with the so.....
» 16/09/2019 2:25:50 AM . To all and sundry, . Whatever the cause or contributing factors that determine our se.....
» 13/09/2019 11:13:21 PM . (Continued …) . All this is explained in Prof. Douglas Pike’s article “Introduction o.....
» 13/09/2019 11:07:04 PM . Dear Loudmouth, . You wrote : 1. « Wish you were here ! Then you might have a more a.....
» 12/09/2019 11:13:37 PM . Dear Loudmouth, . You wrote : « As I've tried to point out many times, the colonial .....
» 12/09/2019 8:53:41 PM . (Continued ...) . And to conclude : « 63 …The common law of this country would perp.....
» 12/09/2019 8:51:08 PM . Dear ALTRAV, . The High Court judges carried out a very thorough analysis of the lega.....
» 12/09/2019 12:18:21 AM . Dear ALTRAV, . I understand your position. It’s an opinion shared by many of our fell.....
» 11/09/2019 8:10:19 AM . Dear Yuyutsu, . You wrote : « As for jails filling with aboriginals, it is a tragedy.....
» 11/09/2019 7:29:53 AM . Dear ALTRAV, . You wrote : « We are not the ones "filling the jails with blacks.....
» 10/09/2019 12:44:04 AM . @ Foxy (ladies first), ALTRAV, Loudmouth & Yuyutsu, . We have been living in this cou.....
» 9/09/2019 6:12:58 AM . Dear Loudmouth, Yuyutsu, ALTRAV and HenryL, . In the March quarter 2019, the average .....
» 9/09/2019 12:25:13 AM . Dear Yuytsu, . You wrote : « If that was only an intellectual exercise, a game of ch.....
» 7/09/2019 6:50:13 AM . (Continued …) . Yes, something like that, Joe. That’s because the system is different.....
» 7/09/2019 6:47:10 AM . Dear Loudmouth, . You wrote : 1. « Pretty clearly, a presumption of innocence is a t.....
» 6/09/2019 8:28:20 AM . Dear Loudmouth, . You wrote : « So how do you do that ? Neither a presumption of gui.....
» 5/09/2019 10:14:36 AM . Dear HenryL, . You wrote to ALTRAV : « … with the Pell case, where 4 years previousl.....
» 5/09/2019 2:37:14 AM . Dear Loudmouth, . You wrote : « … Manson died a couple of years ago. So no release, .....
» 4/09/2019 5:01:25 AM . Hi runner ! . On the Rhodes again … homeward bound ? http://www.youtube.com/watch?v.....
» 4/09/2019 3:16:32 AM . Dear o sung wu, . Many thanks for refreshing my memory of the case of the dingo abduc.....
» 3/09/2019 7:51:37 AM . (Continued …) . Unfortunately, there are no statistics for wrongful convictions and w.....
» 3/09/2019 7:43:24 AM . Dear o sung wu, . You wrote : 1. « If we were to stone a person to death, for the cr.....
» 2/09/2019 8:09:11 AM . Dear Paul1405, . You wrote : « War is no excuse for "legalised" murder. Of.....
» 2/09/2019 2:48:20 AM . Dear Mr Opinion, o sung wu & ttbn, . Mr Opinion wrote : « Those among you who condon.....
» 1/09/2019 11:48:23 PM . Dear Yuyutsu, . Regarding the concept of the social contract you ask : « But what abo.....
» 1/09/2019 1:10:06 AM . Dear o sung wu, . You wrote : « … provided the patient is appropriately medicated to.....
» 31/08/2019 8:16:02 AM . Dear o sung wu, . You ask : « Should this ultimate punishment [the death penalty] be.....
» 24/08/2019 8:18:37 AM . To all and sundry, . I think we can agree that nobody can affirm beyond all reasonabl.....
» 21/08/2019 11:50:26 PM . (Continued …) . In Shakespeare’s tragedy, King Lear, Gloucester’s bastard son, Edmund.....
» 21/08/2019 11:46:30 PM . Dear Foxy, . Having read the “Supreme Court of Victoria, Court of Appeal written reas.....
» 19/08/2019 11:44:45 PM . Dear Foxy, . The article on euthanasia was the second of a trilogy I wrote on justice.....
» 19/08/2019 8:57:02 AM . Dear Fozy, . I’m sorry about the link. For some unknown reason, it works for me here .....
» 18/08/2019 2:40:29 AM . As I have already written and published an article on this subject, I provide a link to.....
» 15/08/2019 6:50:49 AM . Dear Alon (the author), . I think it’s worth recalling that in the US presidential el.....
» 4/08/2019 2:29:13 AM . (Continued …) . There are two other statements that you made that, in my view, are in.....
» 4/08/2019 2:01:59 AM . Dear ALTRAV, . In your last post, there is one instance where either you misread or m.....
» 3/08/2019 3:21:04 AM . Dear ALTRAV, . You wrote : 1. « I must confess not subscribing to any particular thi.....
» 2/08/2019 10:42:40 AM . Dear Foxy, . It’s nice to hear from you. Sorry I couldn't get back to you earlier, I .....
» 2/08/2019 2:36:35 AM . (Continued …) . My understanding is that life on earth was triggered by the fortuitou.....
» 2/08/2019 2:26:19 AM . Dear ALTRAV, . Well, it’s good to see you’re fighting fit. I weigh in as a light-heav.....
» 1/08/2019 9:14:36 AM . (Continued …) . While there is every good reason to celebrate strong female participa.....
» 1/08/2019 9:12:41 AM . Equal does not mean identical. Boy and girl, man and woman are by no means identical. T.....
» 31/07/2019 1:03:34 AM . Dear Peter (the author), . The differences that the evocation of your subject brings .....
» 22/07/2019 5:41:45 PM . Dear ALTRAV, . Many thanks for explaining your position. Naturally, I understand and.....
» 22/07/2019 2:09:07 AM . (Continued …) . There is no objective reason to discriminate against either heterose.....
» 22/07/2019 1:53:57 AM . Dear ALTRAV, . You wrote : « Banjo, I agree completely with your last sentence, espe.....
» 21/07/2019 10:25:33 AM . (Continued …) . I see no reason to believe in the existence of deity or supernatural .....
» 21/07/2019 10:21:26 AM . Dear ALTRAV, . Superstition and religious dogma aside, the most plausible explanation.....
» 20/07/2019 1:24:10 AM . Dear ALTRAV, . I see you are a man of conviction. But, obviously, the claim that gen.....
» 19/07/2019 8:55:40 AM . (Continued …) . A 2014 High Court of Australia judgment unanimously ruled in favor of.....
» 19/07/2019 8:39:59 AM . Dear Armchair Critic . You raise some interesting questions there, but you are getti.....
» 18/07/2019 12:29:46 AM . (Continued …) . The Human Rights Law Centre observes that the “active exercise” of t.....
» 18/07/2019 12:24:30 AM . Dear Augusto (the author), . You wrote : 1. « The Morrison government is preparing a.....
» 17/07/2019 3:33:11 AM . (Continued …) . Biological individuality has always been a characteristic of all life.....
» 17/07/2019 3:24:00 AM . Dear Peter (the author), . You wrote : 1. « Free speech is being closed down in the .....
» 9/07/2019 11:25:30 PM . Dear ALTRAV, . The founders, developers and promoters of the Christian religion have .....
» 9/07/2019 8:26:57 AM . Dear ALTRAV, . You advise : « … you seem to have a problem with men » That's an int.....
» 8/07/2019 7:32:30 AM . Dear Rivka (the author), . Israel Folau's outburst reminds me of that phrase in Willi.....
» 4/07/2019 12:44:16 AM . Dear Loudmouth, . You wrote : « "We have no way of knowing, today, if, ..... &q.....
» 2/07/2019 11:59:03 PM . (Continued …) . We have no way of knowing, today, if, at the time, the Aboriginal peo.....
» 2/07/2019 11:43:14 PM . Dear Loudmouth, . You ask : « You don't think choice, including poor choices, had an.....
» 2/07/2019 2:29:46 AM . Dear Peter (the author), . It appears that sex has been commonly practised independen.....
» 1/07/2019 10:27:07 PM . Dear Loudmouth, . You wrote : « Early benefits of colonisation ? … Well, the ration .....
» 1/07/2019 12:48:48 AM . Dear Loudmouth, . I'm inclined to agree with you, Joe. Your reasoning makes good sens.....
» 29/06/2019 11:38:44 PM . Dear Is Mise, . You wrote : « Nor is there any evidence that these early invaders b.....
» 29/06/2019 1:01:53 AM . Dear rhross, . You wrote : « I repeat, even in the time of King George, while token .....
» 29/06/2019 12:51:56 AM . Dear Loudmouth, . You wrote : . « It's a technicality, arising from its assertion o.....
» 28/06/2019 7:07:40 AM . (Continued …) . « … The bill was rejected by the Lords; three days later, the Portlan.....
» 28/06/2019 7:05:38 AM . Dear rhross, . You wrote : « You have suggested it was Government policy. I have sa.....
» 28/06/2019 1:49:32 AM . Dear Loudmouth, . You wrote : « Yes, precisely, pastoral leasehold land is not owned.....
» 27/06/2019 7:35:34 AM . Dear Loudmouth, . I found this on the internet : ACT, Victoria and Tasmania have ne.....
» 26/06/2019 8:36:09 PM . Dear rhross, . You wrote : « Provide sourced links to Government policy supporting.....
» 26/06/2019 7:55:20 AM . Dear rhross, . You wrote : « I said: And the idea that invasion and colonisation by.....
» 26/06/2019 6:15:21 AM . Dear Loudmouth, . You asked : « … how was the beach ? » I didn't go to the beach, .....
» 25/06/2019 12:30:56 AM . Dear rhross, . This is in response to your post of Saturday, 22 June 2019 4:21:42 PM.....
» 24/06/2019 11:27:57 PM . Dear Loudmouth, . I'm back on stream and can now respond to your post of Saturday, 22.....
» 22/06/2019 5:47:34 PM . Dear Loudmouth, Dear rhross, . Thank you for your posts. I'm about to catch a train .....
» 22/06/2019 2:35:26 AM . Dear rhross, . You ask : « Can I ask you why, it was okay for different waves of pe.....
» 21/06/2019 11:09:13 PM . (Continued …) . And I remarked : « In any event, if Aboriginal peoples were deemed t.....
» 21/06/2019 10:51:38 PM . Dear Loudmouth, . You wrote : « There may have been cases of the early SA colonial a.....
» 21/06/2019 8:19:46 AM . Dear Loudmouth, . Thanks, Joe. If I understand you correctly, so far as you are aware.....
» 20/06/2019 8:46:56 AM . (Continued …) . Getting back to our mainstream discussion, here is an article by Doug.....
» 20/06/2019 8:43:32 AM . Dear Loudmouth, . You wrote : « Pastoralists don't own their stations, at least in c.....
» 18/06/2019 11:39:34 PM . Oops ! I should have written : « South Australia’s climate and vegetation were much mo.....
» 18/06/2019 11:30:58 PM . (Continued ...) . «... After 1842 stock owners had to pay $10 per annum for their run..... » 18/06/2019 10:58:12 PM . Dear Loudmouth, . You wrote : « … immigrants were cultivating the soil from the firs..... » 18/06/2019 12:55:46 AM . (Continued ...) . By the way, Joe, it seems the British colonisers didn't do much mo..... » 18/06/2019 12:22:08 AM . (Continued ...) . It seemed to me, therefore, that in our discussions, we should tak..... » 18/06/2019 12:14:40 AM . Dear Loudmouth, . You wrote : « Generally, at least in Australia and perhaps in Fran..... » 17/06/2019 2:14:51 AM . Dear Loudmouth, . You wrote : « 'Farming' is generally defined as requiring the cult..... » 16/06/2019 8:54:09 AM . Dear Loudmouth, . You wrote : « Some land lease in Queensland and WA were issued fre..... » 15/06/2019 2:52:08 AM . Dear Loudmouth, . You wrote : « And so, one can speak of 'sovereignty' far more easi..... » 14/06/2019 9:24:29 AM . Dear Paul1405, . Thank you for those personal details of your close connection to New..... » 13/06/2019 8:02:28 PM . Dear Loudmouth, . All the issues you mentioned in your last post have been very caref..... » 13/06/2019 8:41:02 AM . Dear Graham, . You wrote : « Why not just omit to sing the one offending word, or mo..... » 13/06/2019 4:19:11 AM . (Continued ...) . Clearly, in Latin, whereas 'territorium' carried the sense of 'terr..... » 13/06/2019 4:00:37 AM . Dear Loudmouth, . You wrote : « Thank you, that's what I was after: possibly no refe..... » 12/06/2019 7:59:16 AM . (Continued ...) . And to conclude : « 63 …The common law of this country would perpe..... » 12/06/2019 7:57:24 AM . Dear Loudmouth, . The High Court judges carried out a very thorough analysis of the l..... » 9/06/2019 9:23:43 PM . Dear Loudmouth, . You wrote : « I can't read the copy of Bourke's Proclamation. Does..... » 9/06/2019 9:34:54 AM . (Continued …) . You added : « As for the term, "terra nullius" being used ..... » 9/06/2019 9:29:06 AM . Dear Is Mise, . You wrote : « You should ask "What was the value of Eastern Aus..... » 8/06/2019 1:53:16 AM . Dear Loudmouth, . You wrote: « Sorry, nobody has ever claimed that Australia was uni..... » 7/06/2019 11:47:13 PM . Dear Individual, . You ask: « Any figures/estimates what it's [Australia’s] worth wa..... » 7/06/2019 2:30:40 AM . (Continued …) . ... orphanages, church missions and the more affluent foster homes of..... » 7/06/2019 2:21:18 AM . We’re obviously dealing with a complex problem here. I think it’s worth recalling that..... » 5/06/2019 7:19:31 AM . Dear Loudmouth, . You wrote : « Yes, a nation is a large group of people "speak..... » 3/06/2019 10:52:56 PM . Dear Is Mise, . You wrote : « Do the learned authors not know the meaning of 'Nation..... » 2/06/2019 6:57:08 AM . Dear Is Mise, . That’s interesting. I saw the film “The Scarlet and the Black” on one..... » 1/06/2019 12:16:40 AM . Dear Paul1405, . I just discovered this thread which I see you initiated almost a wee..... » 31/05/2019 1:00:44 AM . Dear Graham, . As I see it … The polls were an indication of the state of mind of t..... » 30/05/2019 3:06:01 AM . Dear Peter, . Ever since their early beginnings, religious orders, particularly those..... » 29/05/2019 1:38:35 AM . Dear Loudmouth, . No, you didn’t say that, Joe. I, [Ban-jo], did. I think it was mean..... » 28/05/2019 2:22:16 AM . Dear Runner, . You wrote : « Your atrocious attempts to justify butchering unborn ba..... » 28/05/2019 1:16:36 AM . Dear Not_Now.Soon, . You indicate that you would prefer women to give birth to unwant..... » 27/05/2019 8:23:39 AM . Dear Runner, . In reply to my comment “A baby does not remain a baby all its life …”,..... » 26/05/2019 10:23:32 PM . Dear Runner, . A baby does not remain a baby all its life. As it develops, we usually..... » 25/05/2019 8:48:54 AM . Dear Not_Now.Soon, . You ask : « What does the book or any reviews and critisms of t..... » 25/05/2019 1:02:18 AM . Dear david f, NNS & OzSpen, . Professor Kenneth Anderson Kitchen is an evangelical Ch..... » 22/05/2019 7:55:29 AM . As a simple citizen, it makes sense to me to anticipate the phasing out of fossil fuels..... » 21/05/2019 12:33:52 AM . Dear Peter, . You wrote : « The writers of the gospels are better described as artis..... » 20/05/2019 8:51:21 PM . Dear david f, . The link opens-up when I click on it. Here it is again : http://www...... » 20/05/2019 8:42:39 AM . Dear Not_Now.Soon, . The educational abortion videos you posted are quite impressive,..... » 19/05/2019 2:09:24 AM . Dear OzSpen, . You cited the gospel of John 15:18-20 in which the author claims to qu..... » 17/05/2019 11:50:15 PM . (Continued …) . « 1. Everyone shall have the right to freedom of thought, conscience ..... » 17/05/2019 11:45:49 PM . Dear Patrick J Byrne (the author), . You wrote : « What about the rights of parents ..... » 17/05/2019 9:49:29 AM . Dear Runner, . You wrote : « give up your lies. Changing the name of an unborn baby ..... » 16/05/2019 2:48:10 AM . Dear Not Now Soon, . You wrote : « I do not see any rejection of these words [“abort..... » 14/05/2019 8:58:55 PM . Dear Runner, . I often wonder, when I see your pithy little snippets on abortion, whe..... » 13/05/2019 11:20:53 PM . Dear Tristan (the author), . For all the reasons, of which I am sure you are aware – ..... » 13/05/2019 9:38:35 PM . Dear Graham, . My family has been living in the bush on the Darling Downs for five ge..... » 13/05/2019 12:40:55 AM . Dear ttbn, runner and nns, . You obviously do not accept the OED definitions of what ..... » 11/05/2019 9:59:33 PM . Dear Andrew (the author), . Freedom of religion is a noble aspiration. Freedom of con..... » 11/05/2019 8:40:24 AM . The U.S. has the worst rate of maternal deaths in the developed world, and 60 percent a..... » 11/05/2019 7:58:35 AM . Dear Graham (the author), . The remarks of the medical personnel and abortion practit..... » 10/05/2019 1:11:41 AM . Dear Runner, . The OED defines secularism as : « the principle of separation of the ..... » 10/05/2019 1:06:59 AM . Dear Max (the author), . Many thanks for that interesting historical and cultural bac..... » 9/05/2019 9:18:20 AM . Dear Graham, . You wrote : « The case of Folau - in which a young working-class man ..... » 8/05/2019 1:12:25 AM . Dear Augusto (the author), . According to the latest Pew Research Report, in 2016, Ch..... » 2/05/2019 12:12:18 AM . Dear Pablo (the author), . You wrote : « … this resurgence of religious matters in pu..... » 1/05/2019 8:44:45 AM . Dear Sells, . You wrote : « Jesus was more about justice in an oppressive time. His ..... » 30/04/2019 9:27:50 AM . Dear Peter, . You ask if Jesus was a socialist. Perhaps he was inspired by Aristoph..... » 27/04/2019 1:58:09 AM . Dear Ponder, . Thank you for kindly explaining that the author’s correct name is Mr R..... » 24/04/2019 9:55:37 PM . Dear Ren Zegang or Zegang Ren, . Perhaps you may be kind enough to tell me which is ..... » 24/04/2019 2:41:05 AM . Dear Natasha (the author), . I am inclined to agree with you. If we want to escape t..... » 21/04/2019 5:59:02 PM . Dear OzSpen, . Belief in historical evidence and proclaiming belief as historical evi..... » 21/04/2019 7:31:24 AM . Dear david f, . Thank you for introducing me to Nicholas of Cusa. He certainly seems ..... » 21/04/2019 6:53:17 AM . Dear Is Mise, . You wrote : « One could call Lourdes a miracle of job creation!! » ...... » 21/04/2019 2:15:20 AM . Dear OzSpen, . You wrote : « You misrepresent what I've stated. I've NOT given the B..... » 20/04/2019 4:13:12 AM . Dear Is Mise, . Sorry if I misunderstood you. I thought the subject was miracles and ..... » 19/04/2019 11:22:54 PM . Dear Is Mise, . Yes, miracles do occur. They are inexplicable. Hence their appropriat..... » 19/04/2019 7:05:44 AM . Dear OzSpen, . You continue to quote the bible as the sole evidence of the existence ..... » 19/04/2019 3:29:49 AM . Dear Is Mise, . If I may butt in on your conversation with David f, allow me to obser..... » 17/04/2019 11:24:30 PM . Happy 20th anniversary, Graham to you and all those who collaborate with you on OLO. F..... » 17/04/2019 10:02:34 PM . Oops! My post got amputated ... . « I know your atheism did not come from the Judeo-C..... » 17/04/2019 7:53:43 PM . Dear OzSpen, . You wrote : « I know your atheism did not come from the Judeo-Christi..... » 16/04/2019 7:39:28 PM . Dear The Inspector, . You wrote : « If you have jettisoned a belief in the existence..... » 16/04/2019 8:57:39 AM . Dear OzSpen, . You quoted my explanation of word definition and commented : « So ..... » 16/04/2019 7:04:02 AM . Dear OzSpen, . You commented : « You are myopic if you read the NT and do not see..... » 16/04/2019 5:36:48 AM . Dear OzSpen, . You quoted my comment … “All too often, I have observed in some peo..... » 15/04/2019 10:59:19 PM . (Continued …) . I understand that "liberal-progressive" was a label used by..... » 15/04/2019 10:56:24 PM . Dear LEGO, . You wrote : 1. « You have stated on this post and on another, that free..... » 15/04/2019 7:35:31 AM . Dear OzSpen, . Yes. Sorry about that. I was a bit pressed for time and missed your re..... » 15/04/2019 2:11:33 AM . Dear SteeleRedux, . Thank you for posting Izzy’s declaration following his meeting wi..... » 15/04/2019 12:40:24 AM . Dear LEGO, . You wrote : 1. « Freedom of Speech is hardly "important" if y..... » 14/04/2019 10:39:46 AM . Something wrong with the link to the brief explanatory note on that bill. Best to open..... » 14/04/2019 10:29:38 AM . Dear LEGO, . You wrote : « What Rugby Australia should have written is this. "R..... » 14/04/2019 8:37:51 AM . Dear OzSpen, . You ask : « Where do you go for your interpretation of 'objective'? »..... » 13/04/2019 8:37:32 AM . Dear Laurence (the author), . The reformation provoked by Martin Luther 500 years ago..... » 13/04/2019 12:00:49 AM . Dear Bill (the author), . Israel Folau posted a meme on Instagram that read: "WA..... » 12/04/2019 9:31:58 PM . Dear OzSpen, . Thank you for sharing your intimate convictions with me. I note with ..... » 11/04/2019 7:08:16 AM . Dear OzSpen, . If I understand you correctly, you deplore that those Christians who a..... » 10/04/2019 7:35:43 AM . Dear OzSpen, . Many thanks for your response. I appreciate it. As you may have notic..... » 9/04/2019 6:58:41 PM . Dear Runner, . You wrote : « … Trump is a breath of fresh air » . I guess you need ..... » 9/04/2019 11:15:38 AM . Dear Spencer (the author), . You ask : « Does it occur to these researchers and the ..... » 3/04/2019 1:50:32 AM . Dear David, . I understand you represent the Liberal Democratic Party (LPD) but descr..... » 28/03/2019 12:13:01 AM . The rise and fall of Cardinal Pell … . … reminds me of the rise and fall of DSK (Domi..... » 25/03/2019 12:50:21 AM . Dear Individual, . You wrote : « … euthanising them would negate punishment. By all ..... » 24/03/2019 9:01:40 AM . Dear individual, . You ask (somewhat facetiously) : « An even greater torture is bei..... » 23/03/2019 1:17:12 AM . A matter of life and death … . Judging from the media reports, there is no doubt that..... » 20/03/2019 8:20:47 PM . (Continued …) . Commenting on the doctrine of the “presumption of innocence”, the Eng..... » 20/03/2019 8:17:33 PM . Dear Shadow Minister, . You wrote : 1. « The presumption of innocence grants no one ..... » 19/03/2019 11:21:30 PM . Dear Shadow Minister, . Deviating from the sacrosanct presumption of innocence in jud..... » 19/03/2019 8:58:47 AM . Dear Shadow Minister, . You wrote : 1. « Given that conviction in a sexual assault c..... » 18/03/2019 2:15:30 AM . Dear Yuyutsu ; . You wrote : 1. « Only a saint is completely devoid of narcissism » ..... » 17/03/2019 10:46:40 AM . Dear mhaze, . You wrote : « Narcissism is a pejorative. » Pejorative means “express..... » 16/03/2019 8:13:05 AM . Dear Peter (the author), . Allow me to suggest that the so-called “conservative” peop..... » 15/03/2019 8:25:16 AM . Oops ! I meant to write “(our Constitutional Monarchy)” – of course – not “(our Inst..... » 15/03/2019 8:17:10 AM . (Continued ...) . In my view, for sex crimes, prosecution and defence should present ..... » 15/03/2019 8:06:08 AM . Dear Shadow Minister, . You wrote : « The moment you abandon the principle of presum..... » 14/03/2019 9:06:20 AM . That said, HenryL, if – based on what would seem to be the logical outcome of Cardinal ..... » 14/03/2019 8:05:01 AM . Dear HenryL, . You wrote : « The rules of evidence have already been changed for chi..... » 13/03/2019 10:52:39 AM . Dear Shadow Minister, . You wrote : « The question should be why are the left whinge..... » 13/03/2019 9:49:47 AM . According to the Crime and Corruption Commission of Queensland, only about a quarter of..... » 12/03/2019 2:56:19 AM . Cardinal George Pell has been found guilty of sexually penetrating a child under the ag..... » 10/03/2019 9:29:52 AM . "Children-check row shows Catholic church has ‘learned nothing’, says senator"..... » 8/03/2019 8:55:46 PM . In case you missed it : . http://www.catholicnewsagency.com/news/french-cardinal-conv..... » 7/03/2019 11:14:30 PM . Dear David (VK3AUU), . You wrote : « There is material evidence. It is the fact that..... » 7/03/2019 10:46:34 PM . There have been widespread reports in the French media in the last few days on the Pope..... » 7/03/2019 1:27:57 AM . Basis of Cardinal Pell’s appeal : . "The VERDICTS ARE UNREASONABLE and cannot be..... » 6/03/2019 6:00:08 AM . “Beyond reasonable doubt” ! . Cardinal Pell’s lawyers are confident that not only the..... » 4/03/2019 2:50:02 AM . There have been widespread reports in the French media in the last few days on the Pope..... » 2/03/2019 4:11:09 AM . Dear Is Mise, Dear runner, . You both wrote : « Is that designation of worst offende..... » 1/03/2019 7:08:29 PM . Revelations of Church-related paedophilia continue around the world and seem to be neve..... » 1/03/2019 9:50:37 AM . Revelations of Church-related paedophilia continue around the world and seem to be neve..... » 26/02/2019 11:29:18 PM . Dear plantagenet, . You wrote : « May His Eminence’s incarceration not be overly str..... » 26/02/2019 1:50:23 AM . (Continued …) . 5. Matthew deliberately connected Jesus to Messianic prophecies in o..... » 26/02/2019 1:46:19 AM . Dear Yuyutsu, . You wrote : « … the question is, what exactly was Jesus referring to..... » 25/02/2019 10:24:38 AM . Dear Yuyutsu, . You wrote : « … the old-testament was finalised around 200AD when it..... » 23/02/2019 2:44:50 AM . (Continued …) . Also, the bible was composed long before the Bohemian Reformation in ..... » 23/02/2019 2:39:28 AM . Dear Yuyutsu, . You wrote : « Thank you, Peter, for this great article. I wish half ..... » 22/02/2019 10:14:33 PM . Dear OzSpen, . Yes, I had Gideons in mind when I wrote « bibles are rarely “given” to..... » 22/02/2019 2:23:24 AM . Dear Peter, . You wrote : « The mistake of the Reformation was to give the bible to ..... » 11/02/2019 8:32:18 AM . (Continued …) . In support of this theoretical view, the current research has shown t..... » 11/02/2019 8:30:08 AM . Dear Peter, . To describe Christianity (“the Church”) in terms of a conflict between ..... » 8/02/2019 2:40:12 AM . Dear OzSpen, . To my observation : “The comparative study would have produced exactly..... » 7/02/2019 1:23:29 AM . Dear OzSpen, . You wrote : « We have many ways to compare the copies to arrive at cl..... » 6/02/2019 9:13:40 AM . Dear OzSpen, . You wrote : «... the issue to which I responded …was whether we can d..... » 5/02/2019 8:59:29 AM . Dear OzSpen, . Commenting on my statement : “the notion of original documents or “ori..... » 4/02/2019 9:46:53 AM . (Continued …) . Mathematically, it is a “zero probability” but not an “impossibility..... » 4/02/2019 9:38:37 AM . Dear OzSpen, . You wrote : « I can agree with you that many believe the Scriptures b..... » 3/02/2019 7:20:42 AM . (Continued …) . To be complete, OzSpen, I should add that as there have been no major..... » 3/02/2019 2:56:59 AM . Dear OzSpen, . In response to my comment : “I’m sure the Gospels, in particular, are ..... » 1/02/2019 10:13:56 AM . (Continued …) . You declare that it is “false” to consider that “Wright cites Matthew..... » 1/02/2019 10:10:21 AM . Dear OzSpen, . You wrore : « Previously you claimed you read 200 of N T Wright's 817..... » 29/01/2019 4:14:50 AM . Dear OzSpen, . You ask me to provide the precise reference for my comment : “as the a..... » 28/01/2019 5:45:46 AM . Dear OzSpen, . You quoted my statement that “Wright has a good analytical mind but, a..... » 26/01/2019 9:16:10 AM . Dear OzSpen, . Oops, my PDF page counter indicated 29 pages for Einstein’s paper on G..... » 26/01/2019 8:08:10 AM . Dear OzSpen, . You wrote : « You read 200 of 817 pages of Prof N T Wright's research..... » 24/01/2019 9:30:07 AM . Dear OzSpen, . You asked : « Do you know what historical science is? Or are you conf..... » 24/01/2019 7:12:37 AM . Dear George, . You asked : « Who offered a "scientific explanation" of any..... » 23/01/2019 8:51:14 AM . To all and sundry, . I must say I am deeply impressed by all those on this forum whos..... » 1/01/2019 9:03:54 AM . Dear NathanJ, . A happy New Year to you too NathanJ. I shall leave it to Peter Selli..... » 31/12/2018 10:21:55 AM . Dear Yuyutsu, . You wrote : [ Dear Peter and Banjo, “people like me, educated in th..... » 28/12/2018 3:19:07 AM . Dear Foxy, . Your declaration of faith is very touching. It does you honour and comma..... » 28/12/2018 12:38:11 AM . Dear OzSpen, . You wrote : « Logic is used in every sentence, paragraph, chapter and..... » 27/12/2018 3:38:36 AM . Dear Peter, . While I have utmost respect for your belief in some sort of divinity, t..... » 12/12/2018 11:31:17 PM . Dear George, . You wrote : « If you google "knowledge vs belief" you get o..... » 12/12/2018 9:35:04 AM . Dear George, . You wrote : « … we, as laymen can chase quotes in support of this or ..... » 11/12/2018 9:46:36 AM . Dear George, . You wrote : « Kant is not mentioned in the list of agnostics you gave..... » 11/12/2018 1:20:27 AM . Dear George, . In case you missed it, here is an interesting article that just appear..... » 11/12/2018 12:39:52 AM . Dear George, . Thank you for advising that from your experience as a professional ma..... » 10/12/2018 7:23:46 AM . . Dear George, . Re : Wikipedia about Kant and Einstein : I am very wary about labe..... » 9/12/2018 8:50:33 AM . Dear George, . You wrote : « I am not a philosopher to critically evaluate Kant. I o..... » 8/12/2018 9:35:51 AM . Dear George, . The depth and perspicacity of your analysis commands my respect. You h..... » 6/12/2018 11:59:35 AM . Dear George, . You wrote: « What you mean to say is that for you what I called trans..... » 6/12/2018 2:48:10 AM . Dear George, . You wrote : « I refer to transcendence as that part of Reality that c..... » 5/12/2018 10:01:03 AM . Dear Not_Now.Soon, . You wrote : « An ongoing problem is to philosophize other peopl..... » 4/12/2018 11:07:33 AM . Dear George, . 1. You wrote : « Reality - objective, all that exists independent of ..... » 28/11/2018 9:49:52 AM . Dear Binoy Kampmark, . You wrote : « The initial target was increased fuel taxes, bu..... » 28/11/2018 2:40:00 AM . Dear Not_Now.Soon, . Thank you for your response and for contributing to this importa..... » 27/11/2018 6:15:24 AM . Suicide is perfectly legal in Australia. We can commit suicide whenever we like and whe..... » 20/11/2018 8:12:36 AM . Dear James Allan, . You wrote : « I am a long-time opponent of these instruments bec..... » 14/11/2018 11:10:23 AM . Good and evil seem an odd couple. Good is an ethical term whereas evil is distinctly re..... » 13/11/2018 1:48:19 AM . Dear Yuyutsu, . You wrote : « Hitler was correct in claiming that we are not humans,..... » 12/11/2018 9:11:56 AM . Dear Yuyutsu, . You wrote : «A person is a physical object … » . That’s Nazi langua..... » 10/11/2018 3:08:37 AM . Dear Yuyutsu, . You wrote : « A precondition for free will is to have a subjective s..... » 8/11/2018 9:42:35 AM . Dear Louis O'Neill, Dear Graham Preston, . It seems to me that Sam Harris’s book on “..... » 31/10/2018 1:37:12 AM . (Continued …) . http://www.guttmacher.org/sites/default/files/article_files/advisory-..... » 31/10/2018 1:31:11 AM . Dear BigAlOz, . I agree, the late David Fergusson’s research is worth mentioning. Th..... » 30/10/2018 2:32:30 AM . (Continued …) . « … Abortion became a crime and a sin for several reasons. A trend of..... » 30/10/2018 2:27:03 AM . Dear Not_Now.Soon, . Pro-Life and Pro-Choice organisations play a significant role in..... » 29/10/2018 12:50:06 AM . (Continued …) . ... the main body of his submission. Also, there is nothing to indica..... » 29/10/2018 12:21:40 AM . Dear BigAlOz, . Having checked-out the four references you quoted in your recent post..... » 27/10/2018 10:43:04 PM . Dear BigAlOz, . All that you say may be true, BigAlOz, but, I’m afraid it’s only one ..... » 27/10/2018 1:18:15 AM . (Continued …) . « … several years later [after the abortion], while studying anatomy ..... » 27/10/2018 1:14:12 AM . So the cat’s out of the bag ! Thanks to the video posted by Toni Lavis we can see and h..... » 26/10/2018 3:19:05 AM . Dear Foxy, . I see with pleasure that you are beginning to know me well. I confirm, i..... » 25/10/2018 2:07:53 AM . Dear Not_Now.Soon, . This abridged version of Madeleine’s speech to a Rally for Life ..... » 24/10/2018 9:51:54 AM . Dear Runner, . Commenting on my statement that “scientists now estimate that planet e..... » 23/10/2018 9:49:06 AM . According to Christian doctrine, the authors and editors of the Bible were led or influ..... » 22/10/2018 6:38:23 AM . Dear Runner, . I thought I should mention that, in addition to being a brilliant (and..... » 21/10/2018 6:58:57 AM . As Foxy soberly observed : « Not surprisingly, opinion polls show public confusion on ..... » 19/10/2018 8:17:24 PM . Dear Runner, . Commenting on my statement : “Human and chimpanzees’ genes split about..... » 19/10/2018 9:43:32 AM . Dear Madeleine, . You wrote : « Choosing abortion is the greatest regret of my life ..... » 13/10/2018 9:29:43 AM . Dear George, . You wrote : « One can "see gravitation" only through its ef..... » 12/10/2018 8:13:58 PM . Dear Yuyutsu, . You wrote : « Your understanding of God seems to be based on literal..... » 11/10/2018 8:01:32 PM . Dear Yuyutsu, . You wrote : « … I cannot conceive how voluntary worship that comes f..... » 11/10/2018 2:31:37 AM . Dear Yuyutsu, . You ask : « I understand "dignity", but what do you mean b..... » 11/10/2018 12:56:47 AM . Dear Not_Now.Soon, . Thank you for indicating your threefold method of determining th..... » 10/10/2018 3:30:47 AM . Dear Yuyutsu, . You wrote : « This is how me and my friends feel when we kneel, genu..... » 9/10/2018 8:51:38 AM . Dear Not_Now.Soon, . You wrote : « If something is true it is unchanging » That’s tr..... » 9/10/2018 12:47:22 AM . Dear Yuyutsu, . Thank you for expanding on your notion of worship. What I intensely d..... » 8/10/2018 2:57:28 AM . (Continued …) . Commenting on my statement «God is a hypothesis that some people bel..... » 7/10/2018 11:58:56 PM . Dear Yuyutsu, . You wrote : « Worship is an expression of love, consisting of the wo..... » 7/10/2018 8:57:58 AM . Dear Not_Now.Soon, . The fact that science still has a lot to learn goes without sayi..... » 6/10/2018 11:16:10 PM . Dear George, . You wrote : « Definition of nothing … : not any thing : no thing … Ag..... » 6/10/2018 10:56:27 AM . Dear Yuyutsu, . You wrote : « … we ought to have faith in God, worship and love Him ..... » 6/10/2018 9:05:59 AM . Dear Not_Now.Soon, . Thank you for reciprocating with your personal story. It corres..... » 5/10/2018 8:51:01 AM . Dear Yuyutsu, . You wrote : « So at the moment there is no God (yet), but possibly in..... » 5/10/2018 7:54:50 AM . Dear George, . The online Apple dictionary you cited requires a paying subscription t..... » 4/10/2018 10:17:25 AM . (Continued …) . That time came 44 years later. I took up my research once again and i..... » 4/10/2018 8:57:09 AM . Dear Not_Now.Soon, . I apologise for not getting back to you earlier. Still, better l..... » 4/10/2018 2:19:25 AM . Dear Yuyutsu, . On God, atheists, agnostics and worship : I consider that there is n..... » 4/10/2018 2:06:22 AM . Dear George, . You wrote : « Your quote describing quantum vacuum shows indeed that ..... » 3/10/2018 9:18:16 AM . Dear Yuyutsu, . You ask : « Now I really don't know anyone who believes that a suppo..... » 3/10/2018 8:04:11 AM . Dear George, . Indeed, the “nothing” I was referring to was the nothing in a quantum ..... » 2/10/2018 8:29:45 AM . Dear Not_Now.Soon, . I have just noticed your long post on page 14 of this thread but..... » 2/10/2018 8:13:26 AM . Dear Yuyutsu, . You wrote : « … I do not know of anyone, religious or otherwise, who..... » 1/10/2018 1:25:10 AM . Dear Not_Now.Soon, . You wrote in the first paragraph of your post : « … either the ..... » 29/09/2018 11:32:33 PM . Dear Not_Now.Soon, . You ask : « What is irrational to the idea that God has always ..... » 27/09/2018 8:07:59 AM . Dear Not_Now.Soon, . Thank you for indicating that various verses in the bible are th..... » 24/09/2018 8:09:31 AM . Dear Not_Now.Soon, . You wrote : « The difference here though is that God has no beg..... » 23/09/2018 8:44:18 AM . (Continued … ) . Life on earth : Life began on earth 3.5 billion years ago. The Sun ..... » 23/09/2018 8:39:58 AM . Dear Yuyutsu, . The speculation of the authors of the Hebrew bible are amusing. They,..... » 22/09/2018 2:48:14 AM . Dear Runner, . You wrote : « … the rationale of something from nothing, design from..... » 12/09/2018 12:31:18 AM . (Continued …) . John Paul II had the good fortune to die peacefully, in office, at th..... » 11/09/2018 7:55:30 AM . (Continued …) . Both Pope Francis and his predecessor, Benoît XVI, are potentially ex..... » 10/09/2018 11:44:42 PM . (Continued …) . The UN, at its inception, refused membership to the Vatican but has a..... » 10/09/2018 11:32:18 PM . To all and sundry, . Pope Francis is as smug as a bug in a rug in refusing to respond..... » 10/09/2018 7:21:16 AM . To all and sundry, . In addressing 75 newly ordained bishops at the Vatican from 34 c..... » 8/09/2018 7:53:54 AM . Dear Yuyutsu, . You wrote : « … once you discover yourself as God, you also discover..... » 7/09/2018 8:41:22 AM . Dear Yuyututsu, . You wrote : « God is not an hypothesis … Without God, our existenc..... » 6/09/2018 2:48:31 AM . Dear Yuyutsu, . You wrote : « Well if you believe that Moses wrote the bible, then y..... » 5/09/2018 2:25:01 AM . (Continued …) . I have full respect for your religious beliefs, Not Now Soon, whateve..... » 5/09/2018 2:17:36 AM . Dear Not Now Soon, . You wrote : « The Historic Jesus theories are a copout … The sa..... » 4/09/2018 2:27:26 AM . Dear Yuyutsu, . Thank you for your comments and clarifications. I am totally illitera..... » 4/09/2018 1:57:53 AM . Dear Not Now Soon, . You wrote : « History will likely tell how much Paul did for st..... » 3/09/2018 8:03:24 AM . Dear CHERFUL, . You wrote : « Funny how woman came out of a man’s rib, but ever sinc..... » 3/09/2018 12:03:35 AM . Dear Yuyutsu, . Many thanks for your kind response. I’m afraid there really is nothin..... » 2/09/2018 11:35:38 AM . Dear Peter, . You wrote : « There is a wonderful hopefulness in Adam's voice when Go..... » 2/09/2018 8:42:00 AM . Dear Not Now Soon, . I tend to think there might be some truth in the theories of Jew..... » 29/08/2018 10:41:01 PM . No doubt, Pope Francis had in mind Saul of Tarsus’ epistle to the Romans : « Romans 1:..... » 29/08/2018 1:04:30 AM . In publishing his reply to a journalist’s question, the Vatican has erased the recommen..... » 27/08/2018 7:06:06 PM . The foundations of the Catholic Church are beginning to tremble from the onslaughts of ..... » 23/08/2018 9:04:07 AM . Pope Francis has issued a 2,000 word letter following the recent Pennsylvania Grand Jur..... » 19/08/2018 10:06:03 PM . Dear Is Mise, . You wrote : « Maggots there are a plenty but that doesn't affect the..... » 18/08/2018 12:37:59 AM . Dear Is Mise, . You wrote : « Just goes to shew what can happen when an institution ..... » 16/08/2018 11:17:28 PM . The horrendous paedophile scandal in the US, following the release of the Grand Jury re..... » 14/08/2018 12:48:38 AM . Dear Is Mise, . You wrote : « The usual quote is "Whom God has joined together,..... » 13/08/2018 1:43:59 AM . Dear Peter, . So, Arius, whose common sense dictated that “the Son was subordinate to..... » 8/08/2018 1:15:06 AM . Dear WilliamS, . You wrote : « … legalising euthanasia would pose a risk to people …..... » 1/08/2018 1:44:25 AM . Dear david f, Dear Toni Lavis, . The bottom line seems to be that while Churchill aut..... » 31/07/2018 8:37:57 AM . Dear David f, . You wrote : « Perhaps, English democracy is like English cooking. [D..... » 30/07/2018 2:20:32 AM . Dear Yuyutsu, . You wrote : « That these bullying gangs that forcibly control this w..... » 29/07/2018 9:22:34 PM . Dear Yuyutsu, . Given the circumstances you describe, I shouldn’t hesitate to move th..... » 28/07/2018 2:52:30 AM . Dear Yuyutsu, . You wrote : « If you want to have a social contract, then everyone i..... » 27/07/2018 1:28:48 AM . (Continued …) . Something that lacks consciousness (e.g., a chair) is neither guilty ..... » 27/07/2018 1:17:25 AM . Dear Yuyutsu, . You wrote : « Legislation is a form of violence, imposed on us from ..... » 25/07/2018 5:32:51 PM . As souls and gods, angels and devils are hypotheses to which I do not subscribe, if you..... » 25/07/2018 12:30:11 AM . (Continued …) . 2. According to the Christian doctrine of “original sin”, what you re..... » 24/07/2018 11:16:49 PM . Dear Not_Now.Soon, . You wrote : « I am Christian … As for … babies … At this stage ..... » 24/07/2018 7:46:53 AM . Dear Yuyutsu, . Thank you for clarifying what you consider constitutes a soul : « it..... » 24/07/2018 12:07:15 AM . (Continued …) . In my post on page 12 of this thread, I indicated, as regards the foe..... » 23/07/2018 11:59:57 PM . Dear Not_Now.Soon, . You ask : « How can it not be considered a biological fact that..... » 23/07/2018 8:07:54 PM . Dear Yuyutsu . You wrote : « Assuming there is no soul, then the concept of morality..... » 23/07/2018 3:58:32 AM . Dear Yuyutsu, . You wrote : « Should no souls exist, then what could possibly be wro..... » 22/07/2018 11:57:51 PM . Dear Yuyutsu, . You wrote : « The difficult question is whether and to what extent, ..... » 21/07/2018 11:35:31 PM . Dear Not_Now.Soon, . You commented : « You mentioned that many if not most jurists a..... » 20/07/2018 11:55:46 PM . Dear Yuyutsu, . You indicate : « … a foetus is … an organism … unless someone identi..... » 20/07/2018 12:54:56 AM . To all and sundry, . I think it would help if we all agree on what exactly a foetus i..... » 18/07/2018 5:28:24 AM . (Continued …) . 10 End of production : The vehicle is complete (but remains to go thr..... » 18/07/2018 1:56:08 AM . Dear Not_Now.Soon, . I have noticed that you are particularly fond of the use of meta..... » 17/07/2018 7:35:40 AM . Oops ! I wrote "perspectives in life" but, of course I meant "prospect..... » 17/07/2018 3:15:59 AM . (Continued …) . A foetus is a life form that is “partly different from” but “totally..... » 17/07/2018 3:07:20 AM . Dear david f, Dear Not_Now.Soon, . david f wrote : « The indigenous people were quit..... » 16/07/2018 7:23:06 AM . Dear Not_Now.Soon, . Famine and food shortage kills more people every year than road ..... » 14/07/2018 11:59:54 PM . Thanks, Yuyutsu. I first published that poem in “The Bulletin” in 1893. Thank you, al..... » 13/07/2018 9:20:29 PM . (Continued …) . He was none of your dolts, he had seen them brand colts, And it seem..... » 13/07/2018 9:15:36 PM . Such is life, . Question : When does life begin ? Reply (the astrophysicists) : On e..... » 12/07/2018 8:01:19 PM . Dear Peter, . The Christian Church buildings are often referred to as “God’s House”, ..... » 12/07/2018 8:20:42 AM . Dear Peter, . In my previous post on page 3 of this thread, I surmised that perhaps t..... » 11/07/2018 1:37:52 AM . Dear Peter, . Here are some interesting facts and figures on abortion : Legal restri..... » 10/07/2018 7:30:33 AM . Dear David (Leyonhjelm), . Don’t count your chickens before they’re hatched, David. ..... » 10/07/2018 2:20:45 AM . (Continued …) . ... prompted the creation of the OIC when he set fire to the pulpit o..... » 10/07/2018 2:14:11 AM . Dear Peter, . You wrote : « The fall of Christendom and the rise of secularism has p..... » 8/07/2018 7:21:27 AM . Dear Is Mise, . You asked : « Are you postulating that Wilson's conviction was God's..... » 7/07/2018 8:22:59 PM . Dear Is Mise, . You wrote : « Christ had no earthly court to which to appeal, Wilson..... » 6/07/2018 10:57:42 PM . For those who may not have seen it, here is an interesting account of the Wilson affair..... » 6/07/2018 9:34:26 AM . It seems that Adelaide’s Archbishop Wilson has decided to play poker with the judges of..... » 5/07/2018 3:06:20 AM . (Continued …) . « Legislation in all jurisdictions identifies the best interests of t..... » 5/07/2018 2:39:39 AM . Dear Is Mise, . You wrote : « However, on the issue of pederasty, I don't think that..... » 4/07/2018 3:08:05 AM . Dear Is Mise, . Yes, I noticed you have a few imperfections, Is Mise. I guess I have ..... » 3/07/2018 1:33:27 AM . Dear Is Mise, . You wrote : « "the penitent must be truly sorry for his sins an..... » 2/07/2018 1:32:31 AM . Dear Is Mise, . I waded through that lengthy article you indicated in the New Advent ..... » 30/06/2018 12:39:09 AM . Dear Is Mise, . You wrote : « It is a condition of Confessional Absolution that the ..... » 28/06/2018 8:48:07 PM . Dear Is Mise, . You indicate : « They [the Christian Churches]do consider it [paedop..... » 28/06/2018 9:12:25 AM . According to the specialists, paedophilia, is a psychiatric disorder which emerges befo..... » 27/06/2018 8:29:56 AM . Dear Peter (Bowden), . There’s no way the Christian Churches could possibly ignore th..... » 26/06/2018 8:33:08 AM . Dear Don (Aitkin), . To understand Trump you have to understand all those Americans i..... » 22/06/2018 8:01:29 AM . Dear. Not_Now Soon, . You wrote : « Even with the OED dictionary of repentance, deep..... » 20/06/2018 8:32:14 AM . Dear Not_Now.Soon, . You wrote : « Your comment on repentance caught my eye … Repent..... » 20/06/2018 7:44:27 AM . Dear Yuyutsu, . You wrote : « It's the old story of the blind men who touched an ele..... » 19/06/2018 11:41:15 PM . Dear runner, . You wrote : « Repentance and faith in Jesus Christ is the only sensib..... » 19/06/2018 9:33:13 AM . Dear Yuyutsu, . You wrote : « Many indeed do refer to God as Love. They are one and ..... » 18/06/2018 6:54:05 AM . (Continued …) . Our problem, our unease, or “existential anxiety”, is the insupportab..... » 18/06/2018 6:43:17 AM . Dear Peter, . Preparing for death as you describe it is a purely egotistical affair :..... » 6/06/2018 1:57:07 AM . (Continued …) . Roberts holds up as a major piece of evidence of his theories, Abraha..... » 6/06/2018 1:44:31 AM . Dear Galen, . A little more about Paul Craig Roberts' article. First, I must acknowl..... » 5/06/2018 1:15:50 AM . Dear plantagenet, . You wrote : « Sorry … sometimes I overly attack the person, rath..... » 4/06/2018 11:18:00 AM . Dear Galen , . You wrote : « … slavery was never a consideration, the entire premis ..... » 4/06/2018 7:47:41 AM . (Continued) . ... thrown much of their youth into prison, created dependence on drug..... » 4/06/2018 7:41:59 AM . Dear Shadow Minister, Dear Loudmouth, . Many thanks for your comments. Much appreciat..... » 3/06/2018 1:00:57 PM . Dear Alan B, . You wrote : « A nation divided against itself cannot stand! » Abrah..... » 3/06/2018 9:42:51 AM . Dear Loudmouth, . As often, your vision of the myriad examples of the inacceptable b..... » 2/06/2018 11:03:01 PM . Dear ttbn, . You wrote : « Perhaps we have different definitions of loyalty » I do ..... » 2/06/2018 10:49:41 PM . Dear plantagenet, . You wrote : « Where you say "[You] cannot comment on that.&..... » 2/06/2018 9:50:13 AM . Dear Plantagenet, Sorry, I omitted to reply to points 2 and 3 of your first post. “2..... » 2/06/2018 8:33:00 AM . Dear Yuyutsu, “I … prefer the … tyranny of one dispassionate person in England … over ..... » 2/04/2018 7:06:51 AM . Dear david f, . You wrote : « … Christianity could disappear as completely as Manic..... » 31/03/2018 11:17:47 PM . Dear Peter, . « The rise and fall of English [and Australian] Christendom » ? For w..... » 22/03/2018 12:16:15 PM . Dear Peter, . Thank you for that interesting review of the ABC’s TV programme on E M ..... » 19/03/2018 2:24:02 AM . (Continued ...) . The biological anthropologist, Helen Fisher, suggested that " ..... » 19/03/2018 2:16:23 AM . Dear NathanJ, . You ask : « Is there life after death? » From a purely biological p..... » 17/03/2018 4:14:07 AM . Dear ttbn, . You ask : « What are you doing about it, BJ? » I vote for politicians ..... » 15/03/2018 9:02:54 AM . Dear Greg (the author), . You wrote : « What continues to puzzle me is why those who..... » 5/03/2018 12:12:08 AM . Dear Loudmouth, . You wrote : « Two populations, separated mainly by that pastoral-s..... » 4/03/2018 11:31:14 AM . Dear Loudmouth, . As I have often remarked on this thread, your extensive personal kn..... » 3/03/2018 2:43:21 AM . (Continued …) . It is time to take stock of the situation and initiate a more sensibl..... » 3/03/2018 2:12:11 AM . Dear Loudmouth, . Thanks for those details. I see that in the prime minister’s 2018 ..... » 2/03/2018 11:11:05 AM . Dear Loudmouth, Dear Luciferase, . Thank you, once again, Loudmouth, for sharing your..... » 1/03/2018 4:02:32 AM . (Continued …) . « In remote Australia, many older Aboriginal people retain the knowle..... » 1/03/2018 3:57:06 AM . Dear Loudmouth, . Here are some interesting facts relating to domestic violence in Au..... » 28/02/2018 1:44:55 AM . (Continued …) . … were sexually harassed on public transport between 2014 and 2015, i..... » 28/02/2018 1:37:20 AM . Dear Loudmouth, . The breakdown of the traditional social organisation of our Aborigi..... » 27/02/2018 12:05:36 AM . Dear Loudmouth, . You wrote : « "Preservation" ?! Surely it stands or fall..... » 26/02/2018 7:04:18 AM . Dear Loudmouth, . Thank you for those reflexions which I find quite remarkable, and f..... » 25/02/2018 8:07:05 AM . (Continued …) . When the Declaration was adopted in 2007 only four countries voted ag..... » 25/02/2018 7:59:12 AM . Dear Loudmouth, . Well, you have had your finger on the pulse of Aboriginal Australia..... » 24/02/2018 11:27:46 AM . (Continued …) . You conclude: “that's their choice and you have no right to demand ot..... » 24/02/2018 11:11:17 AM . Dear Loudmouth, . You wrote : « Banjo, you may wish to preserve Aboriginal people in..... » 23/02/2018 10:39:29 AM . (Continued …) . Very recently in the presence of two clergymen, a man of education n..... » 23/02/2018 10:28:46 AM . Dear Loudmouth,. The Samuel Griffith Society, named after the chief architect of the A..... » 22/02/2018 1:34:04 AM . Dear Loudmouth, . You wrote : « Funny, I've never thought about Indigenous people in..... » 21/02/2018 9:42:30 AM . Dear Loudmouth, . You ask : « So where is the good news ? Where is the chronically b..... » 18/02/2018 8:43:33 AM . Dear Loudmouth, . Thanks for going to the trouble of spelling all that out, Loudmouth..... » 16/02/2018 10:55:22 PM . Dear Loudmouth, . You wrote : « Latest news ! Indigenous people are not like sheep, ..... » 16/02/2018 12:20:24 PM . Dear Anthony (the author), . The general gist of your article makes good sense if, as..... » 15/02/2018 11:14:43 AM . Dear Peter, . You wrote : « The "unseen" refers not to a spooky otherworld..... » 13/02/2018 8:07:45 PM . Dear Yuyutsu, . I wish you and your family a very happy Shivaratri day, Yuyutsu. Unt..... » 12/02/2018 9:27:01 AM . Dear Yuyutsu, . Thanks, Yuyutsu, but I noticed a few incoherencies with your explanat..... » 11/02/2018 9:31:28 AM . Dear Yuyutsu, . You wrote : « The most common parody on religion is how some churche..... » 10/02/2018 9:02:57 AM . Dear Yuyutsu, . Judging from the way you now describe it, Yuyutsu, it appears to me t..... » 9/02/2018 9:23:56 AM . Dear Yuyutsu, . I had prepared a detailed response to your latest post but decided no..... » 7/02/2018 3:15:58 AM . (Continued …) . You noted : « Deities are not religion … » That’s correct. Deities ..... » 7/02/2018 2:49:34 AM . Dear Yuyutsu, . You wrote : « The issue of time (past-present-future) is complex and..... » 6/02/2018 1:56:21 AM . (Continued …) . ... the kinds of leafy matter they use to block their tunnels. Earthw..... » 6/02/2018 1:39:36 AM . Dear Yuyutsu, . You wrote : « Hopes, wishes and expectations belong in the future … ..... » 5/02/2018 11:04:20 AM . (Continued …) . So he asked himself : “Who are these people ? Where are they ? Why ca..... » 5/02/2018 11:00:36 AM . Dear Yuyutsu, . You replied : « God cannot be defined directly in positive terms, bu..... » 4/02/2018 10:50:46 AM . Dear Yuyutsu, . You replied : « In the broadest sense, Religion is the process of co..... » 3/02/2018 10:06:24 AM . Dear Yuyutsu, . You wrote : « Christianity was a Jewish SECT, it was not yet called ..... » 2/02/2018 2:00:04 AM . (Continued …) . You then add : « First study what religion truly is and find actual ..... » 2/02/2018 1:37:40 AM . Dear Yuyutsu, . You wrote : « The author … admits that the Church never represented ..... » 30/01/2018 10:39:05 AM . In “Of the Nature of the Gods”, Cicero (106 BC – 43 BC), considered to be a model of Cl..... » 30/01/2018 9:54:46 AM . (Continued …) . Faith was the strategy that primeval man devised to pacify his early ..... » 30/01/2018 9:39:07 AM . Dear Peter, . You wrote : « … we are now in an age in which the moral guardianship o..... » 28/01/2018 9:27:06 AM . Dear WilliamS, . You wrote : « It's totally obvious that "god" exists » . ..... » 27/01/2018 7:25:33 AM . 30 years jail for a miscarriage . A woman from El Salvador who was jailed for 30 year..... » 26/01/2018 9:33:20 PM . Abortion in Australia . Here are the essential facts on abortion . TYPES OF ABORTI..... » 26/01/2018 4:29:14 AM . Dear Wendy, . You wrote : « Revealing a most unfortunate lack of understanding and i..... » 25/01/2018 9:27:10 AM . Dear Ashbo, . I just found "Justice - A Matter of Life and Death" on the Au..... » 25/01/2018 8:55:18 AM . Dear Ashbo, . I just checked the link I provided for my article “Justice – A Matter o..... » 23/01/2018 9:07:47 PM . Dear Ashbo, . You wrote : « I won't respond in kind (to your last post). Your positi..... » 22/01/2018 7:15:09 AM . Dear Ashbo, . I see that the number of your arguments against capital punishment has ..... » 21/01/2018 10:23:24 AM . (Continued … . ... the carrying out of the Messianic purposes which rendered the dea..... » 21/01/2018 10:16:05 AM . Dear Ashbo, . You wrote : « I'm an atheist by the way - god does not exist for me (n..... » 20/01/2018 4:30:11 AM . (Continued …) . « Life imprisonment is an extremely shameful measure, worse that a de..... » 20/01/2018 4:26:49 AM . Dear Ashbo, . Thank you for your reply, which I appreciate. It seems to me that the ..... » 19/01/2018 10:36:38 AM . (Continued …) . more than 50% sure. I see “conclusive evidence” as a micron less than..... » 19/01/2018 10:28:37 AM . Dear AJ Philips, . Thank you for those interesting and well documented posts. I agree..... » 18/01/2018 9:58:43 AM (Continued …) . The evidence in the cases I cited in my post to Ashbo qualifies as what ..... » 18/01/2018 9:44:13 AM . Dear AJ Philips, . You wrote : « Like science, the law does not deal in absolute cer..... » 17/01/2018 2:57:21 AM . (Continued …) . ... only be reserved for the most heinous crimes » I grant you that ..... » 17/01/2018 2:43:22 AM . Dear Ashbo, . You indicate that the first and foremost reason for your opposition to ..... » 16/01/2018 12:27:37 AM . (Continued …) . My daughter and granddaughters have not seen him for the past few yea..... » 15/01/2018 11:57:57 PM . Dear diver dan, . You advised : « Best to rely on the Jewish interpretation of love...... » 15/01/2018 1:14:21 AM . Dear diver dan, . You ask : « Quite frankly, it is hard to find two Christians agree..... » 14/01/2018 12:11:10 PM . (Continued …) . allomothering (foster mothering), cooperative foraging, and mutual pr..... » 14/01/2018 12:08:35 PM . (Continued …) . allomothering (foster mothering), cooperative foraging, and mutual pr..... » 14/01/2018 12:03:03 PM . Dear diver dan, . You suggest : « Since Christianity is a sect with Jewish heritage,..... » 12/01/2018 10:29:57 PM . Dear Yuyutsu, . You ask : « … how can anyone love (put first) that which they percei..... » 11/01/2018 11:08:26 PM . (Continued …) . I met my wife in Paris and we have been through many years of stormy ..... » 11/01/2018 10:58:47 PM . Dear diver dan, . You wrote : « Define your version of love ! » It seems there is n..... » 11/01/2018 4:16:37 AM . Dear Peter, . I would like to enlarge on the point I made about love because I think ..... » 10/01/2018 2:11:46 AM . Dear Tristan Ewins, . You wonder : « … how can we explain free-will and consciousnes..... » 10/01/2018 12:05:26 AM . Dear Peter, . You wrote : « … nothing stands, even the closest love of child, countr..... » 9/01/2018 7:50:09 AM . Dear Not_Now.Soon, . I agree with your simple but eminently wise reflection (page 25 ..... » 9/01/2018 7:00:09 AM . Dear AJ Philips, . You wrote : « There is much evidence to suggest that capital puni..... » 8/01/2018 10:13:39 AM . (Continued …) . Nature has attributed many life forms with immune systems capable of..... » 8/01/2018 10:09:56 AM . Dear Ashbo, . You ask : « It seems to me you … accept that miscarriages of justice h..... » 7/01/2018 4:25:44 AM . (Continued …) . Unfortunately, as I pointed out, even in the best of conditions, perf..... » 7/01/2018 4:12:19 AM . Dear Ashbo, . You ask : « Can you try this for me : Imagine YOU are facing the deat..... » 6/01/2018 11:16:36 PM . Dear AL TRAV, . An “Aboriginal” cineaste came through here quite some time ago now, a..... » 5/01/2018 11:39:10 PM . Dear AL TRAV, . You wrote : « I do not believe in the many reasons I have heard j..... » 5/01/2018 11:31:03 PM . Dear AL TRAV, . You wrote : « I do not believe in the many reasons I have heard just..... » 5/01/2018 2:27:27 AM . Dear AL TRAV, . You ask : « Banjo, I confess, your knowledge of religion and it's wo..... » 4/01/2018 9:09:52 AM . (Continued …) . Saul of Tarsus had a long history of religious fanaticism. He partic..... » 4/01/2018 9:06:07 AM . Dear AL TRAV, . You wrote : « My point is that Australia started from convict beginn..... » 3/01/2018 11:59:54 AM . Dear AL TRAV, . You wrote : « The real majority of the first 'white' Australians wer..... » 3/01/2018 12:27:02 AM . (Continued …) . Despite all the pitfalls and imperfections, I, personally, consider t..... » 3/01/2018 12:24:14 AM . Dear Ashbo, . You ask : « So, do you carry out the death penalty, knowing there is a..... » 2/01/2018 10:56:42 AM . (Continued …) . I have never been attracted to any sort of Mafiosi or criminal netwo..... » 2/01/2018 10:48:28 AM . Dear AL TRAV, . You wrote : « … you mask the real Australia by not acknowledging it'..... » 1/01/2018 3:29:53 AM . Dear AL TRAV, . (Continued …) . The productivity rate of Australia in 2017 is sligh..... » 1/01/2018 1:36:25 AM . (Continued …) . If the country works, despite our out-dated constitution and despite ..... » 1/01/2018 1:28:56 AM . Dear AL TRAV, . You wrote : « I found that Aussies are not a mature and knowledgeabl..... » 31/12/2017 8:32:22 AM . Dear AL TRAV, . You wrote : « To explain; from birth my lifestyle has been contrary ..... » 30/12/2017 9:22:29 AM . Dear AL TRAV, . You wrote : « Unfortunately Australia is a stand out country of patr..... » 29/12/2017 10:08:22 PM . Dear AL TRAV, . My heart goes out to you, my friend. I fully understand what you mean..... » 29/12/2017 7:30:34 AM . Dear AL TRAV, . I am pleased to learn that you have managed to arrive at an informed ..... » 28/12/2017 3:35:39 AM . (Continued …) . « Human sexual orientation is influenced by biological, cognitive, cu..... » 28/12/2017 3:31:32 AM . Dear AL TRAV, . I note your particular attachment to norms and the importance you pla..... » 27/12/2017 2:18:19 AM . (Continued …) . It’s not the fault of nature either. There is no right or wrong in na..... » 27/12/2017 2:13:52 AM . Dear AL TRAV, . You ask : « Are you saying that homosexuality is as natural as heter..... » 26/12/2017 1:52:30 AM . (Continued …) . Also, I don’t know how you feel, but, I must say that I am more than ..... » 26/12/2017 1:46:04 AM . Dear Tristan, . You wrote : « But there's a difference between self-awareness on the..... » 25/12/2017 10:04:44 AM . (Continued …) . And, unless I am mistaken, the range and sensitivity of consciousness..... » 25/12/2017 10:01:17 AM . Dear Tristan, . You wrote at the outset of your article : « I will argue that there ..... » 17/12/2017 12:03:56 PM . Dear Ian, . The evolution of religion depends entirely on demographic factors such as..... » 16/12/2017 10:43:16 AM . Dear Ian (the author), . I don’t think the decline in the belief in God has anything ..... » 13/12/2017 4:28:22 AM . Dear Graham Preston & Peter Sellick, . I have just (rather belatedly) discovered your..... » 27/11/2017 2:02:01 AM . Dear David, . There comes a time when there are so many holes in the rusty old bucket..... » 10/11/2017 9:39:37 PM . Dear ALTRAV, . You wrote : « I care not why the change was made. Obviously it aided ..... » 10/11/2017 8:50:16 AM . Dear ALTRAV, . You wrote : « I haven't changed my position, I simply see the interpr..... » 9/11/2017 10:13:46 PM . Dear ALTRAV, . You wrote : « … the correct outcome is to retain the current interpre..... » 9/11/2017 1:29:59 AM . (Continued …) . Virginia Bell, a justice of the High Court of Australia, observed dur..... » 9/11/2017 1:09:01 AM . Dear ALTRAV, . You wrote : « If it was not written into the constitution I would not..... » 8/11/2017 1:37:56 AM . (Continued …) . Jurors receive a small payment for each day of attendance. Employers ..... » 8/11/2017 1:05:00 AM . Dear ALTRAV, . You wrote : « As I still see no mention of removing a jury from a tri..... » 7/11/2017 2:33:48 AM . (Continued …) . You added : « BTW I still have not had any comments on why we are n..... » 7/11/2017 2:28:27 AM . Dear ALTRAV, . Thank you for explaining your world view as it applies to the constitu..... » 5/11/2017 10:55:42 PM . Dear ALTRAV, . You wrote : « Banjo, staying with what I have written previously » N..... » 5/11/2017 8:39:42 AM . (Continued …) . In fact, 1989 was the first time that a plaintiff was successfully a..... » 5/11/2017 8:30:28 AM . Dear ALTRAV, . You wrote: « I don't see these problems you speak of with the current..... » 4/11/2017 9:49:16 AM . Dear ALTRAV, . You wrote : « I do not mind being beholding to Britain … I like the f..... » 4/11/2017 1:02:32 AM . Dear Brendan, . There comes a time when there are so many holes in the rusty old buck..... » 25/10/2017 6:49:00 PM . Dear Yuyutsu, . You wrote : « You cannot expect from me any solidarity with a body-o..... » 25/10/2017 3:18:56 AM . (Continued …) . Might I add that, from a purely moral point of view, I, personally co..... » 25/10/2017 3:16:04 AM . Dear Yuytsu, . You wrote : « Realistically, it is very unlikely for too many people ..... » 24/10/2017 3:07:50 AM . Dear Yuytsu, . You wrote : « The state has no right to prohibit assisted killing, bu..... » 23/10/2017 9:26:58 PM . Dear NathanJ, . Thanks for your explanations but I still consider that governments sh..... » 23/10/2017 7:50:03 AM . Dear NathanJ, . I wrote : « I couldn’t agree with you more as regards the privacy of..... » 23/10/2017 2:47:27 AM . (Continued …) . are loss of autonomy and dignity and being less able to enjoy life’s ..... » 23/10/2017 2:43:08 AM . Dear Not_Now.Soon, . You ask : « If you have the reference handy I'd like to see whe..... » 22/10/2017 2:07:51 AM . Dear NathanJ, . You wrote : « Having high respect for the vast medical specialists I..... » 21/10/2017 9:00:01 AM . Dear Not_Now.Soon, . According to the latest statistics, in 2016, about 8 people died..... » 21/10/2017 1:18:10 AM . Dear Yuyutsu, . Thank you for that clarification. You are right in thinking that I ..... » 19/10/2017 11:40:11 PM . (Continued …) . Euthanasia is not, however, a question for the medical profession to ..... » 19/10/2017 11:37:53 PM . (Continued …) . Euthanasia of convicted criminals must necessarily be carried out in ..... » 19/10/2017 11:33:26 PM . Dear Simon (the author), . I fully subscribe to Yuyutsu’s words of wisdom : « The fr..... » 17/10/2017 11:11:25 PM . Dear George, Dear Peter, . I often wonder if prolific writers take the time to re-rea..... » 17/10/2017 7:00:07 AM . Dear Peter, . You have elevated your mysticism to a paroxysm of ecstasy on that one, ..... » 16/10/2017 11:20:35 PM . Dear George, . Thank you for the link to your article on “The nature of reality”. An ..... » 15/10/2017 10:05:28 AM . (Continued …) . As I tried to explain in my previous post, the only “time” I am capa..... » 15/10/2017 10:02:42 AM . Dear George, . You point out : « You obviously misunderstood my TECHNICAL (semantic?..... » 14/10/2017 1:32:02 AM . Dear Yuyutsu, . You wrote : « Here are some things that we can indeed agree on … » ...... » 14/10/2017 12:46:19 AM . (Continued …) . Although I try to keep an open mind on everything, I do my best to k..... » 14/10/2017 12:40:43 AM . Dear George, . You wrote : « It is a deeper philosophical (semantic) question, wheth..... » 13/10/2017 12:50:06 AM . (Continued …) . Having invented the supernatural, we elaborated a strategy for surviva..... » 13/10/2017 12:39:27 AM . Dear Jayb, . Thank you for those interesting comments. Allow me to make the following..... » 12/10/2017 7:21:12 AM . Dear Peter, . You conclude : « Any healing of the Church, which is now in disarray o..... » 12/10/2017 5:45:54 AM . Dear Yuyutsu, . I understand that the precise number of religions in the world is not..... » 12/10/2017 12:53:21 AM . Dear Yuyutsu, . You wrote : « While no positive description of God is possible, one ..... » 12/10/2017 12:05:30 AM . (Continued …) . As for the Czechs and East Germans, defenders of "our Christian ..... » 11/10/2017 11:57:37 PM . Dear George, . You wrote : « You make me nostalgic, because this is exactly what I l..... » 11/10/2017 1:33:46 AM . Dear Yuyutsu, . You wrote : « Description?? I would be stupid indeed to attempt to d..... » 11/10/2017 12:25:55 AM . Dear George, . You wrote : « Western Europe, apparently on its way to Islamisation, ..... » 10/10/2017 7:14:49 AM . Dear nicknamenick, . If Spinoza’s pantheism equates to “chance and necessity” (which ..... » 10/10/2017 6:50:59 AM . Dear George, . It’s nice to hear from you again. You ask : « Is one right in interpr..... » 10/10/2017 12:17:47 AM . Dear Yuyutsu, Dear George, . Yuyutsu wrote : « God Himself/Herself has no shape or f..... » 9/10/2017 1:25:22 AM . Dear Peter, . Further to my previous post (page 7 of this forum) : In his post-synod..... » 7/10/2017 11:45:52 PM . Dear Peter, . The theological concept of the trinity clearly reflects the macho menta..... » 29/09/2017 12:00:24 AM . Dear Philip S. . Many thanks for your response. As regards my comment that « we wer..... » 27/09/2017 11:05:34 PM . Dear Philip S, . It seems only right to me that, like every other country in the worl..... » 21/09/2017 9:56:33 PM . Dear Graham, . Unless I have misunderstood your calculations, it seems to me that the..... » 7/09/2017 7:20:10 AM . I should add that, much to my regret, I did not invent the wheel either - and yet, wher..... » 7/09/2017 12:29:09 AM . Graham wrote : « I don't see much point in arguing about why the Aborigines were so pr..... » 2/09/2017 11:04:12 PM . Dear Leo Lane, . You wrote : « Banjo, what are the "sovereign rights" you ..... » 2/09/2017 1:00:48 AM . Dear Graham, . You wrote : « Certainly Cook didn't expect to find uninhabited lands ..... » 3/05/2017 6:22:10 PM . Dear David, . I get your point, David. It might be nice to have an Australian as our ..... » 1/05/2017 8:18:50 AM . (Continued …) . We have no alternative but to take up arms against them. We must stop..... » 1/05/2017 8:10:40 AM . Dear Foxy, . The Christian Reformation took about 150 years to complete. Though most ..... » 30/04/2017 6:55:36 AM . Oops ! I meant to write : Contemporary Salafis (the usurpers of Al-Afghani’s term) are..... » 30/04/2017 6:41:26 AM . (Continued …) . It was with the help of these tools that he could attain happiness. H..... » 30/04/2017 6:35:16 AM . Dear Foxy, . Thanks for the link to the “Best Answer” to the question “How can Islam ..... » 29/04/2017 8:33:59 AM . Dear Foxy, . I’m sorry not to have replied earlier to your last post “regarding relig..... » 28/04/2017 11:25:18 AM . (Continued …) . And I have just as reasonably explained, Leoj, that, having read the ..... » 28/04/2017 10:56:37 AM . Dear Leoj, . You wrote : « … then I must have Jewish origins. I don't … » That’s OK..... » 28/04/2017 7:44:29 AM . Dear John, . Australia was ranked 8th Best Country in the world by the US News Report..... » 27/04/2017 9:08:18 AM . I thought I should share this one with you, Joel (Oops ... Loej) : http://www.uua.org/..... » 27/04/2017 8:59:34 AM . Dear John, . I see you shoot from the hip ... and there are an awful lot of holes in ..... » 26/04/2017 7:16:36 PM . Dear Leoj, . You wrote : « You appear to attack the personality of the reviewer but ..... » 26/04/2017 6:07:00 AM . (Continued …) . I first heard of Ayaan Hirsi Ali when the Dutch film director, Theo v..... » 26/04/2017 6:02:27 AM . Dear Leoj, . You wrote : « That was a lot of personal marketing … » It was intended..... » 25/04/2017 7:15:09 AM . Dear Foxy, . Thank you for your link to the article on Karen Armstrong’s book. I read..... » 25/04/2017 2:57:31 AM . (Continued ...) . It follows that their motivation is not to be found in religious be..... » 25/04/2017 2:49:06 AM . Dear leoj, . Thank you for giving me the opportunity of clarifying a number of popula..... » 24/04/2017 7:37:07 AM . Dear leoj, Shockadelic and o sung wu, . I read your posts with interest and thank you..... » 23/04/2017 6:45:17 AM . (Continued ...) . In response to your comment regarding “contributory negligence” on ..... » 22/04/2017 10:47:41 PM . Dear o sung wu, . You wrote : ... in commenting on the domestic violence prevention ..... » 22/04/2017 1:38:39 AM . Dear Runner, . You wrote : « yeah meanwhile today in France and yesterday in USA ..... » 21/04/2017 9:59:42 PM . Dear o sung wu, . You ask : « … what should we all do about it [domestic violence] ?..... » 21/04/2017 2:36:47 AM . Graham wrote : « If Australians are really serious about this violence, then they need..... » 20/04/2017 7:01:36 AM . Dear Phanto, . You wrote : « They [women victims] also fear the criticisms and deris..... » 19/04/2017 8:13:37 PM . Intimate partner violence is endemic in Australia, but we are not alone in that, and it..... » 19/04/2017 9:27:44 AM . Dear Graham, . You wrote : « If a woman wants to voluntarily submit to such a regime..... » 18/04/2017 1:46:49 AM . (Continued …) . But, as we all know, Yuyutsu, nothing in this world is perfect, Even..... » 18/04/2017 1:24:36 AM . Dear Yuyutsu, . You wrote : « Perhaps the constitution never intended to protect rel..... » 16/04/2017 11:09:20 PM . (Continued ...) . From this, it derives that all belief is “binding” and that all bel..... » 16/04/2017 11:01:27 PM . Dear Yuyutsu, . You wrote : « ... "secularism" has, this way or the other,..... » 15/04/2017 7:31:06 AM . (Continued …) . You ask : « How could they [the Commonwealth] possibly tell what's r..... » 15/04/2017 7:23:11 AM . Dear Yuyutsu, . You wrote : « … I understand 'secular' to mean "worldly" …..... » 14/04/2017 5:56:46 PM . Dear Foxy, . My best wishes to you and yours too, Foxy, for a relaxing and enjoyable ..... » 14/04/2017 1:19:43 AM . Dear Yuyutsu, . You suggest : « … one of the uses of the word 'secular' is derived f..... » 13/04/2017 1:29:45 AM . Dear Peter, . You wrote : « Secularism is an ideology … » Not according to the Oxfo..... » 12/04/2017 11:03:43 PM . Dear Foxy, . I wrote an article entitled “Justice – A matter of Life and Death” that ..... » 9/04/2017 2:26:15 AM . (Continued …) . For Saul, religion appears to have been the sublimation of the death ..... » 9/04/2017 2:16:34 AM . Dear Greg, . You posit: « The Bible is a mainstay of Western life » I think it woul..... » 3/04/2017 3:21:35 AM . Dear Runner, . Thanks for the link but, unfortunately, it didn’t work. However, I ma..... » 2/04/2017 9:40:13 AM . Perhaps I should add that the White Australia policy ended with the Racial Discriminati..... » 2/04/2017 9:16:30 AM . Dear Foxy, . You wrote : « I don't quite understand how 18C of the Racial Discrimin..... » 1/04/2017 2:09:05 AM . The rejection by the Senate last night must have come as a bit of a disappointment, not..... » 30/03/2017 10:58:55 AM . Dear Graham, . An excellent, well-documented article in support of the Prime Minister..... » 28/03/2017 7:14:45 PM . Dear leoj, . You ask : « How can a brown, sun-burned land be white? » . We do ha..... » 27/03/2017 6:51:37 AM . Dear Mike, . You wrote : « … Stan Grant said: "The Australian dream is rooted i..... » 24/03/2017 11:51:35 PM . Dear Luciferase, Dear phanto, . There comes a time when there are so many holes in th..... » 24/03/2017 2:18:12 AM . Dear Tombee, . You wrote : « Nothing highlights more the absurdity of 18C and the hy..... » 28/02/2017 9:45:05 AM . (Continued …) . You then wrote : « And here is a link referencing Aboriginal use of ..... » 28/02/2017 9:39:06 AM . Dear Graham, . You wrote : « … your … asserting that the "Abrahamic" relig..... » 25/02/2017 11:16:29 AM . (Continued ...) . The various phases in the timeline of the social development of hum..... » 25/02/2017 11:04:11 AM . Dear Graham, . You wrote : « "The action of the legendary Jesus no doubt render..... » 23/02/2017 10:24:46 PM . (Continued ...) . It is amusing to note in this respect that so-called modern day lai..... » 23/02/2017 10:15:48 PM . Dear Graham, . You wrote : « Banjo, I think you have a severe comprehension problem...... » 23/02/2017 10:04:52 AM . (Continued ...) . The rest of the people will hear of this and be afraid, and never a..... » 23/02/2017 9:56:11 AM . Dear Graham, . You wrote : « … the sermon from our church last Sunday … explores a c..... » 22/02/2017 4:04:26 AM . (Continued …) . by it and if the government and laws do not conform to the “General W..... » 22/02/2017 4:02:24 AM . Dear Yuyutsu, . You wrote : « Governments will still do what governments do for mille..... » 22/02/2017 1:47:41 AM . Dear Runner, . Not to worry, my friend, I think I understand your predicament. Am I ..... » 21/02/2017 12:30:32 AM . Dear Runner, . You wrote : [ « … it was the scientific method applied to my body tha..... » 20/02/2017 9:12:38 AM . Dear Yuyutsu, . You wrote : [ “to ‘opt-out’ of society, one has to either cease bein..... » 20/02/2017 7:24:22 AM . Dear Runner, . You wrote : « ' I prefer the scientific method to blind faith.' You h..... » 19/02/2017 10:24:41 AM . Dear Runner, . « We probably are not to far off in our belief as far as Government is..... » 18/02/2017 1:35:52 AM . Dear Runner, . Many thanks for your definition of “secularism” and additional clarifi..... » 17/02/2017 6:28:56 AM . Dear Najla, . You wrote : « Islam is the religion I choose to follow because contrar..... » 17/02/2017 12:22:59 AM . Dear Runner, . You wrote : « secularism with many of its filthy dogmas was never goi..... » 16/02/2017 2:37:31 AM . Dear nicknamenick, . You wrote : [ ".. living in total seclusion as a hermit, w..... » 15/02/2017 9:23:35 AM . Dear nicknamenick and Yuyutsu, . Many thanks for those articles of law which I read w..... » 14/02/2017 9:00:01 AM . Dear Yuyutsu, . You wrote : « ... Australia, where the option to opt-out from societ..... » 14/02/2017 12:43:03 AM . Dear Yuyutsu, . The Human Freedom Index 2016, a global measurement of personal, civil..... » 11/02/2017 1:38:36 AM . Dear NathanJ, . You wrote : « Firstly, you did not answer my point re future predict..... » 10/02/2017 8:42:03 AM . Dear NathanJ, . Sorry, I'm a bit tied up right now. I'll try to get back to you tomor..... » 9/02/2017 7:09:58 PM . Dear leoj, . Thanks for that interesting testimony. It just goes to show you that y..... » 9/02/2017 10:51:07 AM . Dear NathanJ, . You conclude : « … suicide and euthanasia, simply don't provide answ..... » 8/02/2017 9:39:17 AM . Dear NathanJ, . Thank you for your explanations but I am having difficulty understand..... » 7/02/2017 8:33:37 AM . Literary licence, Is Mise ... ...... » 7/02/2017 3:33:04 AM . Dear diver dan, . You wrote : « I think euthanasia is a conspiracy by the medical fr..... » 7/02/2017 1:03:46 AM . Dear NathanJ., . You wrote : « … most Australians are always free, most of the time...... » 6/02/2017 7:49:09 AM . Dear Alan B., . I fully understand and share your distress at the fact that suicide i..... » 5/02/2017 1:29:10 AM . Continued … . You then wrote : « The fact that many 15 (FIFTEEN) to 44 year olds as ..... » 5/02/2017 12:44:10 AM . Dear Alan B, . You wrote : « In any of our major hospitals, euthanasia is routine an..... » 4/02/2017 4:11:18 AM . According to the latest statistics, a total of 1 611 people hung themselves in Australi..... » 29/01/2017 11:11:33 AM . Dear Alan B., . Though I am not sure to have understood all of your post, the message..... » 27/01/2017 11:08:01 PM . Dear Graham, . The historical significance of the 26th January as Australia Day is no..... » 18/01/2017 2:31:46 AM . Dear Peter, . You concluded : « The Church must be at the forefront in limiting the ..... » 12/01/2017 7:32:24 AM . Dear Yuyutsu, . You wrote : « Advanced computers, so I fear, will be able to do the ..... » 12/01/2017 6:56:41 AM . Dear George, . You wrote : « Apologies for wrongly assuming that you thought conscio..... » 11/01/2017 7:25:06 AM . (Continued …) . Life is neither matter nor energy nor some hypothetical supernatura..... » 11/01/2017 3:21:44 AM . Dear Yuyutsu, . You wrote : « You and I are not entities » An “entity” is something..... » 11/01/2017 12:34:26 AM . Dear George, . You wrote : « So your preferred context is neuroscience, which is mor..... » 10/01/2017 7:21:45 AM . Dear George, . You wrote : « Of course, consciousness (the same as free will) is a fu..... » 10/01/2017 6:13:09 AM . Dear Yuyutsu, . You wrote : « … it is YOU and I who are conscious and aware - not ou..... » 9/01/2017 2:06:05 AM . Dear George, Dear Yuyutsu, . Thank you both for your comments and observations. The..... » 8/01/2017 4:21:34 AM . Dear George, . Thanks for your input. I appreciate it. You indicate : « I fail to s..... » 6/01/2017 7:28:20 PM . Dear George, . Thank you for your kind New Year’s greetings. I wish you and yours a v..... » 6/01/2017 2:28:22 AM . Dear George, . Thank you for sharing the gist of Penrose’s contemplation on conscious..... » 5/01/2017 3:15:33 AM . Dear Peter, . You wrote : « Computers will never reach consciousness. There is an in..... » 4/01/2017 2:12:16 AM . Dear Graham, . Happy New Year to you and yours too, Graham, as well as to all our fel..... » 2/01/2017 2:04:27 AM . Dear Shadow Minister, . You wrote : « My point is that the borders in 1949 included ..... » 1/01/2017 12:28:01 AM . Dear Shadow Minister, . You ask : « As there were no demarcated permanent border lin..... » 31/12/2016 11:58:10 PM . Dear Josephus, . You wrote : « On this occasion Prime Minister Turnbull and Foreign ..... » 31/12/2016 8:15:55 PM . Dear Shadow Minister, . You wrote : « So the mass murder of its citizens and the the..... » 30/12/2016 6:19:03 PM . Dear Shadow Minister, . You wrote : « … the new president, especially one whose part..... » 30/12/2016 7:20:43 AM . Dear Shadow Minister, . You wrote : « A lame duck President initiates a UN resolutio..... » 18/12/2016 10:30:15 PM . This is the treaty I should like us all to sign ... http://www.youtube.com/watch?v=Xba..... » 16/12/2016 12:12:52 AM . (Continued …) . leader of the Pan German Party, which sought to unite the German spea..... » 16/12/2016 12:08:35 AM . Dear Runner, . With reference to Mao, Stalin, Hitler (and Pol Pot), you wrote: « The..... » 15/12/2016 8:56:45 AM . (Continued …) . Orthodox Church) ever declared that he was an atheist or anything oth..... » 15/12/2016 8:50:34 AM . Dear Runner, . You wrote : « … much bad done in the name of religion however in a ve..... » 13/12/2016 9:34:28 PM . Dear Foxy, . I am pleased to hear that your mother is in good hands and that you are ..... » 13/12/2016 7:23:50 AM . Dear Foxy, . I thoroughly agree with your comments and, of course, as previously note..... » 13/12/2016 5:48:39 AM . (Continued …) . The concept of an anthropomorphic deity is unique to Christianity amo..... » 13/12/2016 5:30:07 AM . Dear Foxy, . I fully agree, but you are only looking at the positive sign of the coin..... » 12/12/2016 9:10:36 AM . Dear Foxy, . You wrote : « I have found that my religion has brought me great comfor..... » 11/12/2016 10:15:34 AM . Dear Foxy, . You quoted C.S. Lewis, who wrote: « I believe in Christianity as I beli..... » 10/12/2016 3:28:56 AM . Dear Foxy, . A little heart-warming encouragement from Europe : http://youtu.be/Yfwl..... » 10/12/2016 2:59:14 AM . Dear Foxy, . Euthanasia is a personal decision which each individual should organise ..... » 17/11/2016 11:37:47 AM . (Continued …) . ... punitive justice system should also be revisited so far as it app..... » 17/11/2016 11:30:01 AM . Dear Joe, . You wrote : « Now perhaps we can get back to the key issues in Indigenou..... » 15/11/2016 9:58:52 AM . (Continued ...) . As a conscientious objector, he became an icon of the countercultur..... » 15/11/2016 9:55:12 AM . Dear Joe, . You wrote : « Thanks, but I dispute ALL of your premises » I see that w..... » 14/11/2016 2:14:18 AM . (Continued …) . 1. The Aboriginal tribal elders need to define realistic short, mediu..... » 14/11/2016 2:10:24 AM . Dear Joe, . You wrote : « The remote communities … are the models around which a sep..... » 13/11/2016 10:35:33 AM . (Continued …) . So much for our national operating account. As for our national bala..... » 13/11/2016 10:31:28 AM . Dear Joe, . You wrote : « I recall that Manne's 'discovery' errors was demolished a ..... » 12/11/2016 11:25:57 AM . (Continued ...) . ... thirty billion a year might go some way. And if you want to get..... » 12/11/2016 11:16:29 AM . Dear Joe, . You wrote : « As to Windschuttle's reliability as a historian, your citi..... » 11/11/2016 11:05:13 AM . Dear Amanda, . Thanks for the article. I had missed that. It is a step in the right d..... » 11/11/2016 10:38:28 AM . (Continued ...) . 2. It is estimated that at least 20,000 Aboriginal people were kill..... » 11/11/2016 10:27:32 AM . Dear Joe, . Many thanks for drawing my attention to Keith Windschuttle's latest book,..... » 10/11/2016 10:05:23 AM . Dear Joe, . You wrote : « … across the 'South' (and you know what I mean if you've l..... » 9/11/2016 10:28:39 AM . Dear Joe, . You wrote : « Your ramble about culture is not really relevant any more,..... » 8/11/2016 2:47:34 AM . (Continued …) . Sometimes it’s a hindrance. I learned that very early in my internati..... » 8/11/2016 2:33:52 AM . Dear Joe, . You wrote : « I don't think my wife would have ever claimed to know much..... » 7/11/2016 4:04:18 AM . (Continued …) . I, personally, am incapable of evaluating the legitimacy of these maj..... » 7/11/2016 3:20:49 AM . Dear Joe, . You wrote : « What happens in remote 'communities' is up to the people i..... » 6/11/2016 11:38:54 AM . (Continued …) . And you ask : « Perhaps it's easier to live on welfare, as they are ..... » 6/11/2016 11:34:37 AM . Dear Joe, . You note : « The Queen's likeness is also on all coins. Flora or fauna ?..... » 5/11/2016 8:46:55 AM . (Continued …) . ... is certainly not in their own people’s best interests for aborigi..... » 5/11/2016 8:20:10 AM . Dear Joe, . You ask : « God, where to start ? "the$2 coin has the image of a b.....
» 4/11/2016 1:13:15 AM . Dear Joe, . You wrote : « Re Marx: As a sort-of-ex-Marxist, that's what I've been tr.....
» 3/11/2016 9:52:11 AM . (Continued ...) . [The merchant Edward Lucett declared; "some monkeys I have see.....
» 3/11/2016 9:43:53 AM . Dear Joe, . Thank you for expressing your opinion on this important question. « Wher.....
» 31/10/2016 9:08:22 AM . (Continued ...) . Therefore, should they in a hostile manner oppose a landing and kil.....
» 31/10/2016 9:02:16 AM . (Continued) . they seem’d to set no Value upon anything we gave them, nor would they .....
» 31/10/2016 8:55:40 AM . Dear Loudmouth, . Yes, it’s a sad tale I’m afraid. There has been gross miscomprehens.....
» 30/10/2016 1:02:33 AM . Dear Joe, . You ask : « … should the next generation of children there be sacrifice.....
» 28/10/2016 9:41:41 AM . Dear Joe, . Thank you for those details on Indigenous land tenure in South Australia......
» 27/10/2016 9:53:20 AM . (Continued …) . not the culprits. They seem to have been considered as a hybrid speci.....
» 27/10/2016 1:36:59 AM . Dear Joe, . You wrote : « Solidarity would be fine, if anybody knew what they are su.....
» 26/10/2016 9:39:17 PM . Dear Joe, . You wrote : « So, when I asked if … “you didn't mean to imply that forag.....
» 26/10/2016 9:46:57 AM . (Continued …) . You also wrote : « … Aboriginal graduates are no more responsible th.....
» 26/10/2016 9:16:18 AM . Dear Joe, . You wrote : « … you didn't mean to imply that foraging people were inher.....
» 25/10/2016 8:38:08 AM . (Continued ...) . again, with the 1991 recommendations designed to eradicate any poli.....
» 25/10/2016 8:27:22 AM . Dear AJ & LEGO, . As I understand it, the extraordinarily high crime rate among indig.....
» 24/10/2016 10:43:40 PM . (Continued ...) . Wouldn’t you feel thrown off balance, destabilised, lost, disorient.....
» 24/10/2016 10:33:14 PM . Dear Loudmouth, . You wrote : « 2. If you had moved to France with a one-year-old ch.....
» 23/10/2016 12:54:17 AM . (Continued ...) . I have assimilated French culture to the best of my ability while c.....
» 23/10/2016 12:43:20 AM . Dear Loudmouth, . You wrote : « Culture is not genetic … Culture is learnt … From th.....
» 22/10/2016 12:21:04 AM . (Continued ...) . I could never have imagined it would be possible for any of them to.....
» 22/10/2016 12:03:59 AM . Dear Joe, . You wrote : « … it seems that in the early days in SA, people's curiosit.....
» 21/10/2016 9:45:44 AM . Dear Joe, . You wrote : « … Aboriginal people themselves have to be front and centre.....
» 19/10/2016 2:14:39 AM . Dear Joe, . I am pleased to see that we are on the same wavelength so far as “cultura.....
» 18/10/2016 8:31:50 PM . Sorry, the link only seems to work when you copy it and paste it into your browser sear.....
» 18/10/2016 8:04:05 PM . Dear LEGO, . You wrote : « Your claim that scientists can not find a link between ra.....
» 18/10/2016 12:55:29 AM . Oops, it seems the OLO forum does not recognize certain foreign letters ! The Venitian.....
» 18/10/2016 12:41:01 AM . Dear LEGO, . You wrote : « Intelligence testing of human beings has been around for .....
» 17/10/2016 6:33:01 AM . Dear Craig, . Thanks for introducing me to Roger Waters. I’ll investigate a little fu.....
» 17/10/2016 6:11:39 AM . Dear LEGO, . Welcome back. I hope you had a pleasant weekend and managed to rest up a.....
» 15/10/2016 9:39:16 AM . Dear Loudmouth & Craig, . It’s nice to see you both back on this thread. Loudmouth, .....
» 15/10/2016 8:56:05 AM . Dear LEGO, . You wrote : « Your position, is that the way to world peace is to mix u.....
» 13/10/2016 8:10:15 PM . Dear All, . There is an interesting article in today’s Australian edition of The Guar.....
» 13/10/2016 9:12:02 AM . (Continued …) . We can ignore them just as we ignore the homeless and beggars on the .....
» 13/10/2016 8:57:46 AM . Dear LEGO, . I understand what you are saying and I think there is a lot of truth in .....
» 11/10/2016 8:23:16 AM . (Continued ...) . Today, Australians identify with some 300 ancestries and practise a.....
» 11/10/2016 8:07:10 AM . Dear LEGO, . You certainly paint a bleak picture of humanity and its future prospects.....
» 5/10/2016 9:57:43 PM . Dear LEGO, . You wrote : « … your explanation that racism rests on two basic assumpti.....
» 5/10/2016 1:50:22 AM . Dear Craig, . Thank you for your kind words. This is what the historian, Dante A. Pu.....
» 5/10/2016 12:29:30 AM . Dear LEGO, . You wrote: « But in the case of Roman recognition of races, I think you.....
» 4/10/2016 8:15:15 AM . Dear LEGO, . You wrote: « My apologies, it was Plutarch's "Fall of the Republic.....
» 4/10/2016 1:17:03 AM . Dear LEGO, . You wrote: « You seem to be suggesting that certain existing words in t.....
» 3/10/2016 7:34:38 AM . Dear LEGO, . You wrote : « "Class" may be a "social construct" b.....
» 3/10/2016 1:10:27 AM . Dear Bazz, . You ask : « Does aboriginal custom allow cousin marriage ? Indeed did a.....
» 1/10/2016 10:32:12 PM . Dear LEGO, . You wrote: « Physical appearances are caused by genetics … » Agreed. ......
» 1/10/2016 7:40:44 AM . Dear LEGO, . You wrote: « It was discovered that all races can have people with ver.....
» 30/09/2016 6:19:06 AM . Dear Craig, . You wrote : « In general I agree, but I'd like to muddy the waters a l.....
» 29/09/2016 6:32:33 AM . Dear LEGO, . You wrote : « White Scandinavians can easily be distinguished from bla.....
» 25/09/2016 10:26:38 AM . Dear LEGO, . I am back on stream and can now take up our conversation where we left o.....
» 22/09/2016 6:28:53 AM . Dear LEGO, . Unfortunately, I don’t have time to comment in detail but suggest you re.....
» 4/09/2016 6:47:49 PM . Dear Shadow Minister, . You wrote : « My background as an engineer (30+yrs) has taug.....
» 4/09/2016 1:40:07 AM . Dear Shadow Minister, . You wrote : « I am looking forward to a reasoned rebuttal of.....
» 2/09/2016 10:52:05 PM . Dear LEGO and Shadow Minister, . I'm afraid this debate is beginning to turn in circl.....
» 1/09/2016 2:25:51 AM . Dear Shadow Minister, . You wrote : « The surest way to prevent harm in detention is.....
» 30/08/2016 11:28:59 PM . Dear LEGO and Shadow Minister, . Many thanks for your input. I appreciate your argume.....
» 30/08/2016 5:04:57 AM . LEGO wrote : « If you and Mr Crisp are still advocating … » . Rodney Crisp and Banjo .....
» 30/08/2016 1:54:02 AM . Dear LEGO, . I fully subscribe, without the slightest reserve, to the first three par.....
» 29/08/2016 11:09:18 PM . Dear Shadow Minister, . You wrote : « At least you concede that off shore detention .....
» 29/08/2016 11:18:11 AM . Dear LEGO, . Thank you for expressing your concerns. You certainly paint a bleak pict.....
» 29/08/2016 12:15:06 AM . Not surprisingly, the comments posted here so far are essentially manifestations of the.....
» 29/08/2016 12:04:56 AM . Dear Shadow Minister, . You wrote : « The reality is that illegal immigration droppe.....
» 13/08/2016 8:31:14 PM . it’s the Creator wot done it. He does everythin’ : FRYING PAN'S THEOLOGY Scene: On Mo.....
» 12/08/2016 8:01:57 AM . (Continued...) . Also, about 50% of all heterosexual marriages today, end up in separ.....
» 12/08/2016 6:55:57 AM . (Continued...) . I think you will find that my experience of life is fairly comparabl.....
» 12/08/2016 6:43:48 AM . Dear ttbn, . Many thanks for providing that background information. I appreciate it. .....
» 11/08/2016 2:30:40 AM . Dear ttbn, . You wrote : « All the old stuff about animals and ancients being homos .....
» 10/08/2016 11:15:22 PM . Dear Shimon (the author), . What a pity the “Abrahamic faiths” do not command their a.....
» 10/08/2016 9:41:29 PM . Dear Sells, . Like most visitors at the Museo del Prado in Madrid, I was quite impres.....
» 9/08/2016 1:45:47 AM . Dear Joe (Loudmouth), . That seems to me to be a fairly perspicacious analysis of the.....
» 8/08/2016 2:31:55 AM . Dear Sells, . Commenting on Don Aitkin’s article, “The moral basis of the Left”, yo.....
» 20/07/2016 9:19:13 AM . Dear AJ & David, . Thanks, AJ, your comments are well taken but please be assured tha.....
» 20/07/2016 1:01:35 AM . (Continued ...) . His intent seems to have been to simply underline the greater benef.....
» 20/07/2016 12:50:53 AM . Dear AJ, . It is interesting to learn that « there are many acts that criminologists .....
» 19/07/2016 1:25:08 AM . (Continued ...) . What bothers me is that “deaths due to warfare, genocide, and homic.....
» 19/07/2016 1:22:23 AM . Dear AJ & David, . Sorry to have taken so long to get back to you. My computer stubbo.....
» 15/07/2016 7:11:10 PM . An interesting thought, AJ. Thanks for the quote from Steven Pinker's "The Better.....
» 5/07/2016 6:01:29 PM . Dear Yuyutsu, . You wrote : « Neither of us, I think, has the tools to discern what .....
» 5/07/2016 7:50:46 AM . Dear Yuyutsu, . You wrote : « This elaborate description of origin and behaviour is .....
» 5/07/2016 12:10:59 AM . (Continued ...) . The concept of religion and deity has evolved with the sociocultura.....
» 5/07/2016 12:05:26 AM . Dear Yuyutsu, . I overlooked a question you raised in your previous post : « … relig.....
» 4/07/2016 10:05:46 AM . Dear Yuyutsu, . You wrote : « … nobody denies that you are you or that you are the o.....
» 3/07/2016 9:35:12 AM . (Continued ...) . There is only one person in this whole wide-world who has accumulat.....
» 3/07/2016 9:15:07 AM . Dear Yuyutsu, . « Whatever you perceive through your senses, you can tell that it exi.....
» 2/07/2016 11:03:22 AM . (Continued ...) . As the wheel progresses, the cogs evolve. They become more efficien.....
» 2/07/2016 10:58:16 AM . Dear Yuyutsu, . You wrote : « You are what you are, neither a body nor a soul. While.....
» 1/07/2016 9:18:48 AM . Dear Yuyutsu, . Sorry I couldn’t get back to you earlier. I’ve been a bit busy the la.....
» 27/06/2016 7:26:08 AM . Here's some soul-searching for you ... http://www.youtube-nocookie.com/embed/nPrWo5pEv.....
» 27/06/2016 7:09:44 AM . Dear Yuyutsu, . You wrote : « … only our bodies are conceived by their genitors … » .....
» 24/06/2016 9:44:33 PM . Dear Yuyutsu, . You ask : « Do you participate in life unwillingly? » . We all do, .....
» 24/06/2016 8:49:25 AM . Dear Yuyutsu, . You wrote : « If we dig deep enough, we should arrive at desire(s) t.....
» 23/06/2016 6:23:45 AM . Dear Yuyutsu, . You wrote : « If an action or an interest is rational, this implies .....
» 22/06/2016 8:56:14 PM . Dear Yuyutsu, . I appreciate you sharing your opinion with me. I think I understand w.....
» 22/06/2016 9:33:23 AM . (Continued ...) . Human “rationality” operates within this context and I am inclined .....
» 22/06/2016 9:27:57 AM . Dear George, . Suffice it to say that I read the first half of your post with an acqu.....
» 20/06/2016 11:04:00 PM . Dear George, . The Webster’s Third New International Dictionary definitions of “belie.....
» 20/06/2016 10:18:47 AM . Dear George, . You wrote : « If you are referring to Ockham’s razor (in explaining a.....
» 20/06/2016 3:23:45 AM . Dear Yuyutsu, . Speaking of being saved by faith in my previous post, I indicated : .....
» 20/06/2016 2:51:30 AM . Dear George, . You wrote : « … my concern was only with the (religious) meaning of t.....
» 19/06/2016 9:32:26 AM . Dear Yuyutsu, . You ask : « … how can one talk about "something which does not .....
» 19/06/2016 3:44:01 AM . Dear Yuyutsu, . Your question brings to mind Bertrand Russel’s « Flying teapot » : h.....
» 19/06/2016 1:59:44 AM . Dear George, . I understand your quandary with regard to the appropriate word for rel.....
» 17/06/2016 6:34:54 AM . Dear Peter, . You refer to : « … narrative devices that point beyond themselves to t.....
» 16/06/2016 8:54:52 AM . Dear Peter, . You wrote : « There are two kinds of materialism, the methodological a.....
» 17/05/2016 6:14:49 AM . Dear Dan S de Merengue, . Just as well your father was there, Dan. You never know, bu.....
» 16/05/2016 9:54:42 PM . Dear Rhian, . You explained : « When I said: “Perhaps the most important thing is no.....
» 14/05/2016 11:37:39 PM . Dear Rhian, . You ask : « Have you ever experienced love? » . Yes I have, and conti.....
» 14/05/2016 1:35:33 AM . Dear Rhian, . Thank you for your explanations which I find quite helpful. Though, ap.....
» 13/05/2016 1:47:08 AM . Dear Dan S de Merengue, . You observe : « You sound very French. I've heard that the.....
» 13/05/2016 12:21:44 AM . Dear Rhian, . Thanks for indicating your choice among the numerous OED definitions of.....
» 12/05/2016 6:58:58 AM . Dear Rhian, . You wrote : « Your definition of reality as “something that exists ind.....
» 11/05/2016 2:46:52 AM . Dear Rhian, . You wrote : « Christian liturgy [ritual] does not commemorate an histo.....
» 10/05/2016 10:10:32 AM . Dear Yuyutsu, . I appreciate your drawing my attention to the difference between rati.....
» 10/05/2016 1:33:22 AM . Dear Rhian, . You wrote : « I do not believe in bodily resurrection. If you read the.....
» 9/05/2016 5:51:51 AM . Dear Yuyutsu, . You ask : « Why should people define themselves by whether or not th.....
» 8/05/2016 11:21:50 PM . Dear Dan S de Merengue, . You wrote : « … I would also agree with your later conclus.....
» 6/05/2016 8:17:16 AM . Dear Dan S de Merengue, . You wrote : « Which of the 'gospel' truths do I have in mi.....
» 5/05/2016 9:04:16 AM . Dear Dan S de Merengue, . You wrote : « If I was offered two texts unseen, one take.....
» 4/05/2016 4:28:16 PM . Dear Dan S de Merengue, . You observed : «… if we may try and compare apples with ap.....
» 3/05/2016 7:52:10 PM . Dear johnheininger, . Wikipedia has this to say on the historicity of the gospels : .....
» 3/05/2016 2:15:44 AM . Dear Don (the author), . You’re right. We’ve still got a lot to learn about the unive.....
» 21/04/2016 7:06:40 AM . Dear Peter, . As I am sure you are aware, I have already commented extensively on you.....
» 11/04/2016 10:34:42 PM . Dear George, . You wrote : « As I already said, not being a theologian myself I am w.....
» 11/04/2016 2:52:35 AM . Dear George, . I don’t know if it is of any value to you but I just noticed that an a.....
» 11/04/2016 12:26:29 AM . Dear George, . You wrote : « I do not see any point in discussing pejorative express.....
» 10/04/2016 10:32:57 AM . Dear George, . As I indicated above in my reply to Prebs, I see no justification for .....
» 9/04/2016 5:55:49 PM . « An ant on the move does more than a dozing ox » Laozi ......
» 9/04/2016 8:35:49 AM . If you persist in trying To attain what is never attained If you persist in making effo.....
» 8/04/2016 7:53:18 AM . Dear Prebs, . You wrote : « Faith is terribly defined in the dictionary, as the defi.....
» 7/04/2016 10:58:45 PM . Oops ! The second link should have been the following : http://en.wikipedia.org/wiki/P.....
» 7/04/2016 10:43:50 PM . Dear Peter, . "Faith", as I understand it, is belief where there is no m.....
» 17/02/2016 7:22:54 PM . Here is an interesting slant on Lady Chatterley's Lover : « DH Lawrence's wife 'was th.....
» 17/02/2016 9:15:54 AM . Thanks David, . I found this on the web : « Regrettably, there are many countries wi.....
» 17/02/2016 3:04:03 AM . Dear Peter, . You wrote : « Lady Chatterley's Lover was banned because it was obscen.....
» 11/02/2016 10:15:31 PM . Dear Peter, . You wrote : « Fundamentalism is thus a product of modernity and of sec.....
» 11/02/2016 2:22:17 AM . Dear Peter, . You wrote : « … secularism … refer(s) to a realm that excludes the sac.....
» 24/01/2016 1:00:16 PM . (Continued ...) . Religious discrimination, persecution and war are by no means thing.....
» 24/01/2016 12:51:15 PM . According to the Oxford English Dictionary, the word religion means : « the belief in a.....
» 23/01/2016 11:13:04 AM . Dear George, . « I doubt Geertz meant it as something that could have a multitude of.....
» 23/01/2016 9:29:29 AM . David’s last post reminds me that I have observed over the years that some of the comme.....
» 23/01/2016 8:29:23 AM . Dear George, . You wrote : « I am not sure which definitions of mine you mean … » . .....
» 22/01/2016 9:26:23 PM . Dear Yuyutsu, . You wrote : « Rocks can only lie there and eventually water will run.....
» 22/01/2016 10:38:46 AM . Dear Yuyutsu, Dear George, . Yuyitsu wrote : « In the broadest sense, religion is an.....
» 21/01/2016 10:50:12 AM . Dear George, Dear Yuyutsu, . Various people have various definitions of what constitu.....
» 21/01/2016 12:33:14 AM . Religion and Myth . In « The Oxford Companion to World Mythology » (2005), David Leem.....
» 17/01/2016 10:43:16 PM . Oops ! … in my previous post I wrote : « Greek, Norse and Christian mythologies ». I sh.....
» 17/01/2016 11:00:10 AM . Greek, Norse and Christian mythologies have been largely incorporated into every aspect.....
» 17/01/2016 12:51:00 AM . It just occurred to me that the explanation of Peter’s/Sells’ silence may be that he se.....
» 16/01/2016 10:43:37 AM . Peter Sellick/Sells may possibly have, inadvertently, made a typing error when he wrote.....
» 15/01/2016 9:10:32 PM . Hi David ! . Still no news from Peter Sellick alias Sells, despite his vibrant decla.....
» 15/01/2016 7:43:24 PM . Dear Pete, . The truth of the matter is that the bible is simply an interesting antho.....
» 15/01/2016 11:03:34 AM . (Continued …) . Today we have 4 times more students attending a state school than we .....
» 15/01/2016 10:58:27 AM . Dear Pete, . You published another article on your blog (http://petermulherin.net/?p=.....
» 14/01/2016 7:29:44 AM . (Continued ...) . In other words, Peter, if ever we were tempted to do away with reli.....
» 14/01/2016 2:18:51 AM . Dear Peter, . You wrote : « My criticism of the rationalists, the humanists and the .....
» 5/01/2016 12:43:26 PM . Dear Tristan Ewins, . You wrote to Rhrosty : « … perhaps even God will not protect y.....
» 5/01/2016 11:01:38 AM . (Continued …) . You also oppose “biblical telos” and a so-called “secular telos”. T.....
» 5/01/2016 10:58:43 AM . Dear Peter, . You wrote : « There are traumas so great and so terrible in the lives .....
» 1/01/2016 12:25:26 AM . Dear Peter/Sells, . You wrote (page 9 of this thread) : « Why do I get the feeling t.....
» 31/12/2015 3:00:36 AM . (Continued …) . Well, I doubt that “the Church” will change the date of the celebrati.....
» 30/12/2015 3:16:19 AM . (Continued …) . Of the four gospels in the New Testament, Luke’s is the only to indic.....
» 29/12/2015 9:58:42 AM . (Continued ...) . ... and I think it would be much better to serve just a few light r.....
» 29/12/2015 3:56:06 AM . (Continued ...) . Another barbaric practice of Christianity is the celebration of Mas.....
» 29/12/2015 3:35:48 AM . Dear Jayb, . You certainly seem to have had a pretty heavy religious education. Am I .....
» 28/12/2015 10:38:22 AM . (Continued …) . “The Church” celebrates the feast of the Exaltation of the Holy Cross.....
» 28/12/2015 4:20:34 AM . Dear nicknamenick, . What seems pretty certain is that those 300 bishops who gathered.....
» 27/12/2015 10:51:32 AM . Oops, I forgot to take the "s" off the "https" address in my first .....
» 27/12/2015 10:44:55 AM . (Continued …) . Christianity started as just one of many small sects. Saul of Tarsus .....
» 27/12/2015 10:31:11 AM . Dear Jayb, . Thank you for those interesting details. I admire your science but it wo.....
» 26/12/2015 7:48:22 AM . Dear Peter/Sells, . Though, at the time of the events related in the New Testament, t.....
» 24/12/2015 12:47:50 AM . Dear Peter/Sells, . You ask : « Why do I get the feeling that I could as well publis.....
» 22/12/2015 12:50:23 AM . Dear Peter, . You wrote : « At Christmas the Church proclaims that God has a human f.....
» 18/12/2015 9:54:08 AM . Dear Saints, . You might be interested to learn that a number of Australian scholars .....
» 17/12/2015 1:43:44 AM . Dear SAINTS, . Here is another case of a feeble-minded person apparently acting under.....
» 16/12/2015 2:31:05 AM . Here is an interesting development : http://www.arabianindustry.com/markets/news/2015/.....
» 7/12/2015 10:53:37 PM . Dear SAINTS, . You wrote : « There's just no excuse for anyone wanting to kill/take .....
» 7/12/2015 7:46:36 AM . Dear SAINTS, . You wrote : « The “scumbag” who stabbed three people in London Tube s.....
» 6/12/2015 10:24:08 AM . Dear SAINTS, . Ypu wrote : « It’s time the Grand Mufti of Australia sent a strong me.....
» 4/12/2015 10:45:08 PM . Dear SAINTS, . You wrote : « Aussies ask the obvious question – why is this “so call.....
» 2/12/2015 9:17:00 AM . Dear Baz, . You wrote : « Just what proportion are converts, not all that many I thi.....
» 1/12/2015 12:17:40 AM . Dear Baz, . You wrote : « Rodney said; so many fine, healthy, intelligent young I.....
» 30/11/2015 11:34:12 PM . Dear LEGO, . All those questions you ask appear to be characteristic of radical Musli.....
» 30/11/2015 2:06:35 AM . Dear LEGO, . I have never studied nor even read the Qur’an though I see I have one he.....
» 29/11/2015 11:09:50 AM . Dear LEGO, . We’re certainly on the same wavelength there. I could almost have writt.....
» 29/11/2015 4:29:55 AM . Dear LEGO, . You wrote : « I was not talking specifically about crime. I was saying .....
» 28/11/2015 10:14:36 AM . Dear LEGO, . You wrote : « The concept that nobody can be judged by their group affi.....
» 28/11/2015 4:11:17 AM . Dear Peter, . You wrote : « C S Lewis said … Harry Walton … believes that he has see.....
» 28/11/2015 1:14:28 AM . Dear LEGO, . « The police officer made no social or political comments about Muslims......
» 26/11/2015 4:17:47 AM . Dear LEGO, . You wrote : « I have a book by the British police officer who was in ch.....
» 25/11/2015 1:24:52 AM . Dear David (the author), . You wrote : « I plan to introduce a Private Senators' Bil.....
» 25/11/2015 12:58:30 AM . Dear LEGO, . You wrote : « Islam is a religion which stresses that those who fight f.....
» 13/11/2015 8:57:59 AM . Though modern democracies recognize life as a fundamental human right, the same is not .....
» 8/11/2015 10:50:08 AM . Dear david f, . You wrote: « “That’s where the sons raise meat, and that’s the reali.....
» 8/11/2015 12:50:35 AM . Dear George, . You wrote : « … if “numbers“ is “sufficiently explicit to you” when r.....
» 7/11/2015 9:19:18 AM . Dear George, . Your article, “The nature of reality” and the 23 comments it generated.....
» 5/11/2015 10:13:29 AM . Dear David and George, . The discussion has reached an interesting point and in view .....
» 4/11/2015 1:24:36 AM . Dear George, . You wrote : « The same about “visions” of physical reality. The essen.....
» 2/11/2015 11:08:53 PM . Dear George, . Thank you for those interesting references to the works of Bas C. van .....
» 2/11/2015 3:13:54 AM . Dear George, . « … I agree that “vision” here - where culture and world views (which .....
» 1/11/2015 1:16:38 AM . Dear George, . You quote from Toynbee’s “Christianity among the religions of the worl.....
» 31/10/2015 9:35:00 PM . Dear david f and Suzeonline, . I don’t want to be a spoilsport on such an auspicious .....
» 31/10/2015 9:56:43 AM . Dear David, . Actually, my wife and I got the date wrong and raised our glasses to wi.....
» 30/10/2015 9:50:13 AM . Dear Josephus, . You wrote : « A Bill of rights might give one the right by removing.....
» 29/10/2015 2:55:15 AM . Dear Paul1405, . « Church leaders certainly have had a strong influence, and still do.....
» 28/10/2015 1:44:58 AM . Dear Yuyutsu, . Perhaps I should add that I understand “secular” to mean, essentially.....
» 27/10/2015 11:33:30 PM . Dear Yuyutsu, . No, Paul1405 did not include China and USSR in his reply. Leave them.....
» 27/10/2015 9:01:35 PM . Dear Josephus, . You wrote : « I note you want a Bill of Rights, but more importantl.....
» 27/10/2015 7:28:30 AM . (continued …) . It will also be the occasion to establish a new Constitution : • rec.....
» 27/10/2015 7:23:22 AM . Dear onthebeach, . You wrote : « The republic pales into insignificance and is in fa.....
» 26/10/2015 9:30:23 PM . Dear onthebeach, . You wrote : « … I am happy to withdraw if I did read you wrongly .....
» 26/10/2015 1:44:08 AM . Dear Poirot and Paul 1405, . Thank you for sharing your impressions of onthebeach wit.....
» 25/10/2015 8:43:57 AM . Dear onthebeach, . You wrote : « Struggle Streets? Let them eat cake and pretend th.....
» 24/10/2015 9:46:53 AM . Dear Poirot, . It’s nice to hear from you too. Everything’s fine in Paris. Poor old .....
» 24/10/2015 7:35:57 AM . Dear onthebeach, . Thank you for drawing my attention to : • the drought-stricken fa.....
» 23/10/2015 8:34:59 AM . Dear Nathan J, . Thank you for your kind words. OLO is an interesting melting pot. It.....
» 22/10/2015 9:41:13 PM . Thank you, gentlemen (I presume). Those are all valid observations and objections which.....
» 22/10/2015 11:17:51 AM . Dear Is Mise, . You ask : « …what are the advantages? » The advantages are that fro.....
» 22/10/2015 9:37:58 AM . Australia - republic or constitutional monarchy ? . Australia : Australia's formal n.....
» 21/10/2015 8:03:49 AM . For those of us who have always enjoyed the Australian life-style and can see no reason.....
» 21/10/2015 3:56:11 AM . Also, on the question of religion so far as the Constitution is concerned, allow me to .....
» 21/10/2015 2:39:03 AM . The constitution of Australia was an Act of the Parliament of the United Kingdom. The C.....
» 10/10/2015 11:35:08 AM . Dear Sells, . You wrote to david f. : « Where did you read this history? Is it not a.....
» 8/10/2015 10:33:07 PM . Dear Sells, . You wrote to david f. : « History is always being rewritten in order t.....
» 8/10/2015 12:15:03 AM . I wrote (page 4 of this thread) : « While the church fully recognizes the possibility .....
» 7/10/2015 8:25:32 AM . (Continued …) . To quote one of Siedentop’s critics: « Siedentop's view that the anc.....
» 7/10/2015 8:22:20 AM . Dear Peter, . In the opening words of your article, this month, you indicate : « Inv.....
» 16/09/2015 2:37:07 AM . Dear Peter, . You wrote : «… if God is dead then our death will quickly follow. » . .....
» 13/09/2015 11:08:33 PM . Dear o sung wu, . Your story revives a familiar melody that often plays in my mind as.....
» 12/09/2015 8:46:02 PM . My mother-in-law used to get very upset whenever my wife and I had to drive back to Par.....
» 12/09/2015 12:20:45 AM . Dear Paul (the author), . Life and death are fundamental human rights. Nobody has the.....
» 12/09/2015 12:10:43 AM . Dear Paul (the author), . Life and death are fundamental human rights. Nobody has the.....
» 29/08/2015 1:49:25 AM . Dear John (the author), . You wrote : « Labor's recent decision to opt for a 50% ren.....
» 3/08/2015 11:04:42 PM . (Continued …) . Might I add that it is a common feature in the animal kingdom for mal.....
» 3/08/2015 10:59:23 PM . Dear Eric (the author), . You wrote: « … over the past two hundred years or so in we.....
» 3/08/2015 7:18:55 AM . Oops ! Not "consummation". That's Franglais. Please read "consumption&qu.....
» 3/08/2015 1:20:58 AM . It’s no secret that population growth in undeveloped countries largely exceeds populati.....
» 1/08/2015 9:46:09 PM . Sister Joan Chittister, O.S.B : « I do not believe that just because you're opposed t.....
» 1/08/2015 6:53:51 AM . Dear david f, . You certainly seem to have an interesting family. Arden looks like .....
» 31/07/2015 9:56:45 PM . Dear JP, . You wrote : « Problems arise though when atheists make up conflicting mor.....
» 31/07/2015 10:22:44 AM . Dear JP, . You wrote to George : « … if atheism is true ethical discussion makes no .....
» 29/07/2015 10:40:40 PM . (Continued …) . You concluded : « In a materialistic universe there is no necessity .....
» 29/07/2015 10:37:07 PM . Dear JP, . You ask : « Are you happier with materialistic universe? » No more than .....
» 29/07/2015 10:21:52 AM . Dear JP, . You wrote : « Banjo – both you and davidf seem quite ready to accept that.....
» 28/07/2015 8:30:45 PM . Dear JP, . « … in a universe that has just happened, completely unintentionally, to c.....
» 27/07/2015 11:02:56 AM . Oops! Instead of "Forth century BC Hippocratic oath ...", please read: ".....
» 27/07/2015 10:56:09 AM . Dear Yuyutsu, . You wrote : « Somehow what started in the article as a moral discuss.....
» 26/07/2015 9:18:58 AM . Dear Peter, . You wrote : « There were many reports of this event. I chose to use th.....
» 25/07/2015 5:26:59 AM . Dear George, . Thanks for that link to the “Crux” article of the Boston Globe Cathol.....
» 17/07/2015 6:20:19 PM . Dear Yuyutsu, . As I wrote earlier, I am pleased to see that your religious beliefs a.....
» 17/07/2015 6:11:36 AM . I already expressed my views on this subject in an article the Greens picked up and inc.....
» 16/07/2015 8:31:22 PM Dear YuYutsu, . You wrote : « Religion is not about explaining the world, but about tra.....
» 15/07/2015 9:15:32 PM . Dear Dan, . You wrote : « The gospel message has found me. The invitation to believe.....
» 11/07/2015 8:48:16 AM . Dear Dan, . You wrote : « I choose to believe in these accounts [ the narratives of .....
» 10/07/2015 12:48:24 AM . Dear Dan, . You wrote: « …speaking for myself and most believers I relate with, what.....
» 8/07/2015 10:01:26 PM . Dear Dan, . Here are my answers to your questions - and I hope, this time, I have not.....
» 8/07/2015 7:35:56 AM . Dear Dan, . You ask : « If I'm hearing you correctly, you've decided a long time ago.....
» 7/07/2015 7:14:34 PM . Dear Dan, . You wrote : « It is interesting that those such as yourselves, Banjo, P.....
» 5/07/2015 7:13:31 AM . Dear Dan, . You wrote : « Je pense que celui qui s'approche de Dieu doit croire qu'i.....
» 3/07/2015 6:23:16 PM . Dear Dan, . Following our recent conversation, I just came up with what would seem to.....
» 3/07/2015 7:38:23 AM . Dear Dan, . Nice to see you back. You wrote : « I don't remember Sells ever respond.....
» 2/07/2015 10:06:37 PM . Dear Criag, . You wrote: « I don't share Peter's religious beliefs, Banjo, but I am .....
» 2/07/2015 5:58:36 AM . Dear Dan, . You ask : « I'm not sure about your insistence that Peter respond. What .....
» 1/07/2015 10:43:40 PM . Dear Craig, . You ask: « If a proof of a relatively simply piece of mathematics can .....
» 1/07/2015 6:38:51 AM . Dear Craig, . You wrote: « Nash spent just a few months in hospital, Banjo, admitted.....
» 29/06/2015 11:26:37 PM . Dear Craig, . John Nash is an interesting example. There are many others : Joan of Ar.....
» 29/06/2015 12:35:31 AM . Dear Craig, . You wrote : « The Annunciation story may well be "true". Hav.....
» 28/06/2015 4:23:34 AM . Dear Peter, . You wrote: « I reiterate my point that legends like the crossing of th.....
» 27/06/2015 2:11:20 AM . Dear Peter, . You wrote : « For example, the annunciation to Mary of her conception .....
» 26/06/2015 9:30:12 PM . A major study conducted by University of Melbourne researchers has concluded that same-.....
» 26/06/2015 8:19:35 PM . Homosexuality is a perfectly natural phenomenon, just like heterosexuality. As Petter.....
» 25/06/2015 4:37:35 PM . « I will engage with you if you engage with me ! » Posted by Sells, Thursday, 28 May 2.....
» 25/06/2015 5:51:11 AM . « I will engage with you if you engage with me ! » Posted by Sells, Thursday, 28 May 2.....
» 25/06/2015 5:29:30 AM . Dear Foxy, . Here is an additional element of reflection … Wards of the state: the f.....
» 23/06/2015 7:58:40 PM . Dear Foxy, . In my view, the State is already too intrusive in the private lives of i.....
» 22/06/2015 8:39:36 PM . Dear Craig, . If you need a distraction from the stress of your exams, here is some p.....
» 22/06/2015 1:16:02 AM . Estas Tonne is a modern day Troubadour, born in Ukraine. Reka Fodor is a Romanian actre.....
» 21/06/2015 11:25:46 PM . Dear Craig, . I hope all goes well for you on this last day of your semester. I’m sur.....
» 21/06/2015 2:29:25 AM . Here is my favourite version of Joaquín Rodrigo’s “Concierto de Aranjuez” composed in e.....
» 17/06/2015 9:00:16 PM . Dear Craig, . Welcome back. That was a quick goodbye and hello. Just a stage exit I .....
» 16/06/2015 7:11:03 PM . “There's no lack of void.” “Nothing happens. Nobody comes, nobody goes. It's awful.” .....
» 16/06/2015 3:14:56 AM . And indeed there will be time For the yellow smoke that slides along the street, Rubb.....
» 15/06/2015 9:05:59 PM . Dear Craig, . You wrote : « If you don't want to engage with Peter on Peter's terms,.....
» 15/06/2015 8:39:17 AM . Dear Craig, . You wrote : « sophistry is a fun game, but it is not indicative of goo.....
» 15/06/2015 2:18:45 AM . (Continued ...) . You then wrote : « You see, it's all very easy to poke fun at reli.....
» 15/06/2015 2:06:18 AM . Dear Craig, . You wrote : « Peter has made it clear what he meant by "engage&q.....
» 14/06/2015 10:14:17 AM Dear Craig, . You wrote : « Peter is not asking you or anyone to "engage" on .....
» 13/06/2015 6:45:01 PM . Dear Peter, . You wrote : « I will engage with you if you engage with me! » : http:.....
» 11/06/2015 4:37:28 AM . Dear Peter, . You write : « Belief cannot be equated with faith. » There does not a.....
» 10/06/2015 7:42:46 PM . Last, but not least, one of the world's greatest violinist virtuosos, Niccolò Paganini .....
» 9/06/2015 6:35:07 AM . Dear David and Craig, . I’m glad you liked it. Closer to home in time and space, here.....
» 7/06/2015 8:34:13 PM . To think that Baldassare Galluppi (Il Buranello) preceded Mozart by 50 years ! Listen .....
» 2/06/2015 2:24:25 AM . Oops ! My mistake. Try this ... http://www.youtube.com/watch?v=x8qZmAypUfQ Sorry abou.....
» 2/06/2015 2:19:52 AM . Here are two motets (short pieces of sacred choral music), by Baldassare Galluppi, born.....
» 31/05/2015 10:23:55 PM . My favourite version of Pergolesi’s “Stabat Mater” - composed in 1736 during the final .....
» 29/05/2015 8:18:51 PM . Heaven’s Joy Awaits When We Leave This Low Land We Will Cross The Jordan Pass This .....
» 29/05/2015 8:25:06 AM . Dear Craig Minns, . « What a fascinating digression. » Sometimes an “obiter dictum” .....
» 29/05/2015 12:15:58 AM . Dear Peter, . « I do not think it worthwhile trying to answer comments that are simpl.....
» 29/05/2015 12:06:28 AM . Dear Dan, . « … perhaps you're also suggesting Peter is not being democratic. » No, .....
» 27/05/2015 11:24:16 PM . (continued) . that the OLO forum is “an area for deliberative democracy” : http://po.....
» 27/05/2015 11:11:19 PM . Dear Dan S de Merengue, . « Banjo, What are you looking for from Peter? Are you accu.....
» 22/05/2015 12:27:02 AM . Graham’s response (by e-mail) : . « Hi Rodney, I can’t see anything here I need to d.....
» 21/05/2015 6:28:54 PM . Dear david f, . Thank you for all that detailed information. Apparently there is much.....
» 21/05/2015 9:11:00 AM . Dear Yuyutsu, . « Following Banjo's comment, I like to say that I enjoy Peter's artic.....
» 21/05/2015 7:49:43 AM . Dear david f, . « You modified what I wrote by writing: “Thought-crimes are instrumen.....
» 20/05/2015 6:32:03 PM . Dear Graham Young (the editor), . I am very surprised that this article escaped the v.....
» 20/05/2015 2:46:08 AM . Dear Peter, . I agree with George. I’m afraid you have, perhaps unwittingly, denature.....
» 19/05/2015 11:59:13 PM . Dear runner, . « Rates of domestic violence is much higher in the homosexual communit.....
» 19/05/2015 7:54:25 PM . Dear david f, . « Many of our arguments or discussions in olo seem to me rather point.....
» 19/05/2015 5:09:39 AM . Dear david f, . I wrote : « I vote “no”. Do you maintain your “yes” vote?" » A.....
» 18/05/2015 9:09:32 PM Dear Yuyutsu, . Thank you for that thoughtful post. « Obviously you know better than an.....
» 18/05/2015 7:37:50 PM . Dear david f, . « Bakunin believed that “... the instinct of liberty is lacking in hi.....
» 18/05/2015 12:59:53 AM . (Continued …) . God is not a childhood dream. It is a brilliant concept invented b.....
» 18/05/2015 12:37:13 AM . Dear david f, . « There may be millions who would have been similar monsters had they.....
» 17/05/2015 9:19:20 PM . Dear david f, . « Marx was not only an political thinker and philosopher but was also.....
» 17/05/2015 7:52:36 PM . Dear Yuyutsu, . « … you can follow your childhood dream of serving God without any (i.....
» 17/05/2015 8:37:00 AM . Dear Yuyutsu, . « Now that you realised that God does not exist, you are finally free.....
» 17/05/2015 8:22:00 AM . Dear Yuyutsu, . « Are you also able to give us some rough idea about when the concept.....
» 16/05/2015 11:12:31 PM . Dear Dan S de Merengue, . Your evident sincerity prompts me to make a contribution to.....
» 16/05/2015 8:21:04 PM . Dear david f, . I understand the reasons for your indignation toward Karl Marx despit.....
» 16/05/2015 2:43:39 AM . Dear Pericles & Yuyutsu, . Pericles wrote to Yuyutsu: « At least you are able to acc.....
» 16/05/2015 12:22:33 AM . Dear david f, . « Marx’s ideas did change the world. However, my opinion is that his .....
» 14/05/2015 11:11:25 PM . Dear david f, . « Banjo Paterson quotes Marx. Marx was good at making witty aphorisms.....
» 14/05/2015 12:28:47 AM . Dear ConservativeHippie, . « If Banjo's theory is correct, which is a big stretch, th.....
» 13/05/2015 11:32:47 PM . Dear thinkabit, . « Banjo Paterson: Your account of the raise of civilisation and com.....
» 13/05/2015 6:10:13 AM . Dear david f, . « The defining characteristic of capitalism is that the means of prod.....
» 12/05/2015 8:04:57 PM . Let us cease our idle chatter, Let the tears bedew our cheek, For a man from Tallangatt.....
» 11/05/2015 8:42:28 PM . Dear o sung wu, . I am sorry to hear of your personal loss. Please forgive me for hav.....
» 11/05/2015 8:33:00 PM . Dear onthbeach, . « I have mixed feelings about euthanasia and assisted suicide, main.....
» 11/05/2015 8:04:38 AM . Dear o sung wu, . « When you think about it Banjo, we're almost regressing in our sea.....
» 11/05/2015 7:55:31 AM . Dear onthebeach, . « It would be difficult to prove 'contributing fault' where minors.....
» 10/05/2015 7:15:28 AM . Dear o sung wu, . « Nations that still practice Capital Punishment, have been see.....
» 10/05/2015 7:02:05 AM . Dear onthebeach, . « There are drug traffickers and drug traffickers. There is a huge.....
» 9/05/2015 1:43:38 AM . Dear o sung wu, . Whereas I consider that the state has an imperious obligation to pr.....
» 29/04/2015 5:26:39 AM . Dear Joe, . « That's life » . You’re right there, Joe … All the best. ......
» 28/04/2015 8:08:08 PM . Dear David, . « The Westminster system violates Montesquieu’s checks and balances. » .....
» 28/04/2015 5:39:05 AM . Dear Joe, . « Your question, 'how much Aboriginal blood you have to have in Australia.....
» 27/04/2015 8:40:51 PM . Dear David, . « Paramount = predominant. We have different views. My view is that if .....
» 27/04/2015 8:16:24 AM . Dear onthebeach, . « You don't think that fires that dramatically reduced and would e.....
» 27/04/2015 7:39:52 AM . Dear Joe, . Thanks for your suggestions of possible explanations of what might have t.....
» 27/04/2015 7:07:33 AM . Dear plantagenet, . Thanks for the link to that “politically correct” speech of Tony .....
» 27/04/2015 6:56:51 AM . Dear David, . « Whose right is paramount - the right of society to enjoy the genius o.....
» 26/04/2015 7:29:07 PM . Dear David, . « Your position is essentially the same as Thomas Jefferson as to the s.....
» 26/04/2015 7:25:42 AM . Dear Joe, . « By the end of this year, around forty thousand Indigenous people will h.....
» 26/04/2015 6:27:18 AM . Dear David, . « How did you determine what is a fundamental human right? » . I didn.....
» 25/04/2015 11:53:39 PM . Dear onthebeach, . « Applying some commonsense and Occam's Razor, it is far more like.....
» 25/04/2015 8:28:19 PM . Dear David, . « Sometimes kamikaze operations are necessary. » . Then, so be it. I o.....
» 25/04/2015 2:21:36 AM . Dear David, . I couldn’t agree with you more. I place too high a price on my freedom .....
» 24/04/2015 11:21:56 PM . Dear Joe, . You certainly paint a colourful picture of Aboriginal life in the old day.....
» 24/04/2015 10:49:47 PM . Dear onthebeach, . « I come from the land and I can assure you that NO fire is withou.....
» 24/04/2015 5:55:48 AM . Dear Joe, . « Re-Thinking Aboriginal History » . Thanks, Joe. I read that summary ar.....
» 24/04/2015 2:03:03 AM . Dear onthebeach, . I wrote : « They (Aborigines) burned the bush to renew and reinvi.....
» 23/04/2015 8:01:20 PM . Dear Joe, . « I think you've answered your own query. Put the time in, my boy, and yo.....
» 23/04/2015 12:22:34 AM . Dear Joe, . « Check out my website: www.firstsources.info - you will find about twelv.....
» 22/04/2015 11:46:59 PM . Dear Is Mise, . « They didn't (live in perfect harmony with their natural environment.....
» 21/04/2015 11:24:31 PM . Dear Is Mise, . « Well said, Banjo, inaccurate and unscientific, but well said none t.....
» 21/04/2015 5:24:02 AM . Dear John (the author), . Colonialism with its habitual panoply of oppression, inhuma.....
» 6/04/2015 8:24:42 AM . Dear Peter/Sells, . You wrote : « This cosy little fest between you does not give yo.....
» 5/04/2015 8:45:14 AM . I can talk to him, Lego, but he can't hear me 'cause he just ain't there ! ......
» 5/04/2015 2:13:21 AM . Happy Resurrection Day to all ! . Time to have a little talk with Jesus : http://www.....
» 5/04/2015 1:13:01 AM . Happy Resurrection Day ! . Time to have a little talk with Jesus : http://www.youtub.....
» 3/04/2015 11:07:14 PM . Dear George, . On « relative freedom of thought and independence of mind » : . I hav.....
» 3/04/2015 7:54:43 AM . Dear George, . You wrote : « I do not understand how a child could have accepted the.....
» 2/04/2015 8:34:20 PM . Dear George, . You wrote : « >> I knew you would not take kindly to that expre.....
» 2/04/2015 3:04:38 AM . Dear George, . You wrote : « I think we all are free to perceive a text the way we w.....
» 2/04/2015 2:59:21 AM . Dear Pericles, . You ask : « Is there a difference, Banjo Paterson? » [between the d.....
» 1/04/2015 1:05:20 AM . Dear George, . Thank you for Clifford Geertz’s anthropologist’s “scientific definitio.....
» 31/03/2015 8:20:45 AM . Dear George, . You wrote to Craig : « I agree that one difference between mathematic.....
» 31/03/2015 8:14:42 AM . Dear Peter, . I find your article, this month, to be an honest, unbiased presentation .....
» 17/03/2015 2:03:56 AM . Dear Runner, . You wrote : « I suspect we have not heard of the name of most heroes......
» 17/03/2015 1:46:19 AM . Dear Sophie (the author), . You wrote : « Like most Australians, I am implacably opp.....
» 10/03/2015 12:49:52 AM . I was young and fancy-free when I was living in Australia. My only possessions were the.....
» 7/03/2015 12:55:26 AM . Dear Peter, . You wrote : « The medical model of mental health with its focus on bra.....
» 6/03/2015 10:33:41 PM . Dear Foxy, . It’s a PDF document. This link might work better : http://www.google.fr.....
» 5/03/2015 8:51:03 PM . Dear Foxy, . Thank you for that for that excellent post. It appears so well-informed .....
» 4/03/2015 10:02:41 PM . Dear David (the author), . Perhaps you might like to read the following article : h.....
» 27/01/2015 7:21:38 PM . In the symposium on “Free Speech” organised last year by the Australian Human Rights Co.....
» 27/01/2015 1:21:21 AM . A sub-title on the “public sector guidance sheet” on the topic of “Right to freedom of .....
» 25/01/2015 8:47:40 AM . Dear david f, . « ... the problem is that some individuals hearing such words from an.....
» 24/01/2015 12:02:20 AM . Dear david f, . « To ask religion not to promote hatred, violence and terrorism is li.....
» 23/01/2015 9:27:32 PM . Dear david f . « 1. France has separation of religion and state. The government has n.....
» 23/01/2015 10:13:47 AM . Dear david f, . « One can make a distinction between the ordinary law-abiding Muslim .....
» 22/01/2015 8:53:23 PM . Dear david f, . « <<Though I have not seen the report, its author was interview.....
» 22/01/2015 8:02:42 AM . Dear David and George, . There are a couple of things I thought I should mention : T.....
» 21/01/2015 10:04:47 AM . Dear david f, . « The knowledge wasn't wasted. The advances made during early Islam f.....
» 20/01/2015 9:22:26 AM . Dear david f . « At that time Christian Europe was in the Dark Ages, and Islam was fa.....
» 20/01/2015 2:08:59 AM . Dear George, . « I do not think Jews need to be integrated into Western culture since.....
» 19/01/2015 9:40:16 PM . More about Confucius and reciprocity ... . « The doctrine of reciprocal response is c.....
» 19/01/2015 6:58:13 PM . Bowdlerising Charlie Hebdo … . Thomas Bowdler explained in « The Family Shakespeare ».....
» 18/01/2015 9:45:12 PM . Dear ConservativeHippie, . You wrote : « Charlie simply pushed too far and paid the .....
» 18/01/2015 10:58:58 AM . Dear George, . You opine : « I do not think Jews need to be integrated into Western .....
» 18/01/2015 9:51:10 AM . Dear david f, . Thanks for that interesting panorama of Tea Party Republicans and Dom.....
» 18/01/2015 5:50:44 AM . Dear George, . You asked : « Do the French want to live with Muslims who resent such.....
» 18/01/2015 1:51:36 AM . Dear Jay of Melbourne, . You wrote (on page 10 of this thread) : « … they [the Charl.....
» 17/01/2015 10:07:29 AM . DearGeorge, . « Where I see problems is when indecency, rudeness, impudence etc are .....
» 17/01/2015 7:30:10 AM . Dear Yuyutsu, . «… a common Australian expression is "I can't [do such-and-such].....
» 16/01/2015 8:29:54 AM . Dear George, . « The question is only whether this implies the right to offend, insul.....
» 16/01/2015 3:15:50 AM . Dear Yuyutsu, . You conjectured (on page 7 of this thread) : « I am yet to see Austr.....
» 16/01/2015 1:09:52 AM . Dear david f . You recalled (on page 7 of this thread) : « A Japanese friend visited.....
» 15/01/2015 10:48:14 AM . Dear George, . « I gather the site represents a minority view in France. What do you .....
» 15/01/2015 9:18:07 AM . Let's try that link again : http://ouvirmusica.com.br/neil-diamond/839770/ ......
» 15/01/2015 9:13:05 AM . Dear Foxy, . Many thanks for your response (top of page 14 of this thread). I am sur.....
» 15/01/2015 1:39:56 AM . Charlie Hebdo . The sale of the resuscitated Charlie Hebdo got off with a bounce this.....
» 14/01/2015 3:42:39 AM . Dear Foxy, . You wrote to Rhian : « I think that the Charlie Hebdo cartoons would be.....
» 14/01/2015 1:28:13 AM . Dear Yuyutsu, . Every country is unique. Each has its own particular culture, traditi.....
» 13/01/2015 10:16:02 PM . Dear Philip S. & Poirot, . Two million people participated in the march in Paris. In .....
» 13/01/2015 3:39:38 AM . Dear Foxy, . You ask : « Freedom of Speech - Is it too big a price to pay? » . That.....
» 12/01/2015 11:21:12 PM . For those who are not familiar with Charlie Hebdo, perhaps I should add that it derides.....
» 12/01/2015 10:18:32 PM . Dear George, . We have just lived through an intensely emotive experience here in P.....
» 9/01/2015 1:32:34 AM . Dear Foxy, . Thank you for raising this important topic. I was not aware of Julie B.....
» 8/01/2015 12:00:54 AM . Dear Jay Of Melbourne, . You observe : « It's about 10,000km from Melbourne to Sou.....
» 7/01/2015 1:54:25 AM . Dear Jay Of Melbourne, . You observe : « Australia isn't part of Asia … » That’s co.....
» 6/01/2015 10:17:33 PM . Dear Foxy, . Having said all that, perhaps I should answer your question : “ Should A.....
» 6/01/2015 7:49:25 PM . Dear Foxy, . Thank you for your kind New Year wishes. Please accept mine in return fo.....
» 3/01/2015 4:30:34 AM . Dear Mike (the author) . Allow me, once again, to recall that your article concludes:.....
» 31/12/2014 10:27:28 PM . a modest contribution to the yuletide festivities … . http://www.youtube.com/watch?v=.....
» 31/12/2014 1:05:08 PM . Dear Mike (the author) . « Even if there is no God, there was still an historical Jes.....
» 15/12/2014 6:40:54 PM . Dear Peter, . I have not read Updike’s novel but judging from your brief description .....
» 1/12/2014 7:44:57 AM . Dear Constance, . «Donnie Darko was made in 2001 so you would have to rent it out » ......
» 30/11/2014 11:45:43 AM . Dear Constance, . Thanks for the PIL clips. I get the message - disappointment - but .....
» 29/11/2014 2:10:40 AM Hi Constance, . I guess there’s just the two of us still on this thread. I’m not sur.....
» 28/11/2014 12:26:53 AM . « Nor did the Pope, the Archbishop of Canterbury or the head of the World Council of Ch.....
» 27/11/2014 12:33:04 AM . Dear PaulMurrayCb, . You enquired : « … why does anyone bother replying to this drive.....
» 25/11/2014 11:50:28 PM . Dear Dan S de Merengue, . You remarked : « I'm not sure if Peter believes in an afte.....
» 25/11/2014 9:05:30 PM . Squeers wrote : « This is how I think of liberal rationalism: blindly rationalising &.....
» 25/11/2014 8:44:55 AM . Dear George, . You concluded : « Whether we like it or not, there is no satisfactory.....
» 24/11/2014 6:38:56 PM . Not to mention, also, all those poor souls who continue to join the ranks of Isis or Da.....
» 24/11/2014 6:17:47 PM . Oops! I forgot to take the "s" off that link. Let's try this : http://www.yo.....
» 24/11/2014 6:11:47 PM . Dear George, . « “Belief in afterlife” : note that I used quotation marks to indicate.....
» 24/11/2014 8:22:10 AM . Dear George, . Thank you for your explanations and clarifications. I am pleased to.....
» 23/11/2014 8:33:28 AM . Dear George, . You protested : « I am certainly not aware of ever having “invalid.....
» 22/11/2014 11:08:22 PM . Squeers : « The difference between 'soul' and the others is 'immortality' is it not? ».....
» 21/11/2014 9:47:58 PM . Dear Squeers, . You wrote : « Atheism is as much a world view as its opposite. It's .....
» 21/11/2014 5:32:31 PM . Dear Sells, . You confessed : « Upon reading the above I regret my previous dismissa.....
» 18/11/2014 10:49:05 PM . Dear George, . Nice to hear from you. In responding to Squeers, I indicated : « Geor.....
» 18/11/2014 7:32:19 PM . Dear Squeers, . Thank you for clarifying that. It seems our positions are fairly simi.....
» 18/11/2014 1:24:14 AM . Dear Squeers, . You wrote: « ‘Faith’ can also imply calculated belief, ‘such as this.....
» 17/11/2014 7:57:21 PM . Dear Squeers & AJ Philips, . « Where atheism/rationalism does border on religion is i.....
» 17/11/2014 8:48:31 AM . Dear Rhrosty, . You wrote : « Atheism seems also to go hand in hand with an absolute.....
» 16/11/2014 12:07:44 AM . « Sells who is void of wisdom despiseth his readers: but a man of understanding holdeth.....
» 15/11/2014 1:30:40 AM . Dear Peter Sellick, . You wrote : « There is no such thing as pure atheism, we alway.....
» 1/11/2014 12:11:07 AM . Dear Peter Sellick, . You wrote : « God remains a reality before which we must give .....
» 28/10/2014 1:34:41 AM . Dear Peter Sellick, . You wrote : « … there exists an unbridgeable gap between matt.....
» 15/10/2014 9:58:03 PM . (Continued …) . Binary labelling may correspond to a certain type of logic but, in my.....
» 15/10/2014 9:55:28 PM . Dear AJ Philips, . You really are a remarkable intellectual contortionist, AJ. You li.....
» 15/10/2014 9:28:50 AM . Dear AJ Philips, . Thank you for your patience. I too shall try to take another bi.....
» 14/10/2014 7:02:34 AM . Dear AJ Philips & George, . There is, of course, a third combination that comes to mi.....
» 14/10/2014 1:30:18 AM . Dear George, . You kindly explained : « The devil came into it because of its phonet.....
» 14/10/2014 1:15:19 AM . Dear AJ Philips, . You ask : « Anyway, now that you seem to understand what I meant,.....
» 13/10/2014 1:16:32 AM . Dear George, . You wrote : " When I first came to Paris half a century ago I th.....
» 12/10/2014 9:24:10 PM . Dear George, . You wrote : « You might object to the noun “absolutes” ... the adject.....
» 11/10/2014 11:51:00 PM . Dear George, . Many thanks for the link to that clear and simple explanation of so-ca.....
» 11/10/2014 1:52:01 AM . (Continued …) . I am personally incapable of assessing the value of the article but, .....
» 11/10/2014 1:43:18 AM . Dear AJ Philips, . You wrote : « It’s not that you’re not capable of understanding t.....
» 10/10/2014 10:15:27 AM . Dear George, . I am sorry to have taken so long to get back to you. Thank you for yo.....
» 10/10/2014 8:41:38 AM . (Continued …) . Having said that, AJ, I do not exclude the possibility that my intel.....
» 10/10/2014 8:39:59 AM . Dear AJ Philips, . Thank you for your explanations. I appreciate your patience. Howev.....
» 9/10/2014 2:27:41 AM . Dear AJ Philips, . You wrote : « … we don’t even need to be here to conceive of thei.....
» 8/10/2014 7:27:00 PM . Dear AJ Philips, . You wrote: « So long as there is one person who believes in a god.....
» 8/10/2014 7:20:43 PM . Dear George, . That is a fairly good – not quite perfect – but nevertheless amusing a.....
» 8/10/2014 12:26:58 AM . Dear AJ Philips, . Many thanks for your observations and web links on atheism. You w.....
» 7/10/2014 1:47:29 AM . Dear ConservativeHippie, . I think you will find that there are a number of people on.....
» 17/09/2014 2:38:19 AM . Dear sonofgloin, . You wrote : « The way I see it the only person who legally has a.....
» 15/09/2014 9:27:57 PM . Dear sonofgloin, . Perhaps I should add, to be complete, that, in my view, convicted .....
» 15/09/2014 4:33:56 PM . Dear sonofgloin, . You wrote : « There is also no malice in nature BP........ » You.....
» 14/09/2014 7:52:22 PM . Dear Sonofgloin, . You wrote : « Agronomist ended this argument with this succinct l.....
» 13/09/2014 1:32:01 AM . Intentional murder is an act by which the murderer clearly demonstrates his refusal to .....
» 12/09/2014 5:10:41 PM . We killed 1,193 people on the roads last year in Australia, including 14 cyclists. Vi.....
» 12/08/2014 6:39:59 AM . Dear Sells, . You wrote: « As far as the sexual revolution is concerned do you reall.....
» 18/07/2014 9:15:15 AM . Dear one under god, . You wrote : « i give-up/post/limits/stck-keys/editing-it/into......
» 16/07/2014 7:20:09 PM . Dear one under god, . As I indicated previously, I think the conflict between Israel .....
» 16/07/2014 6:11:18 AM . Dear one under god, . You quoted me : <<..It‘s a two-sided coin. On the oth.....
» 15/07/2014 8:11:27 AM . Hey ! It’s 14 July 2014. The 225th anniversary of the French revolution ! Here’s Tchai.....
» 15/07/2014 7:49:17 AM . « As the African Proverb says: Whoever walks fast, travels alone. Whoever walks far, wa.....
» 15/07/2014 12:45:52 AM . Dear one under god, . You wrote : « banjo/that mess\in irael has nothing/to do with .....
» 14/07/2014 7:08:14 AM . Dear one under god, . If the worst comes to the worst, it may be possible to allocate.....
» 14/07/2014 2:59:52 AM . Dear one under god, . You wrote : « how can you lot remain mute/its lies all round [.....
» 7/07/2014 8:20:42 AM . Dear Yuyutsu, . You wrote : « … you could either serve your bodily passions, or you .....
» 6/07/2014 8:30:58 PM . Dear Yuyutsu, . You wrote : « God doesn't need anything - it's us who need to serve .....
» 5/07/2014 5:38:53 AM . (Continued …) . Saul was a Jew and had a long history of religious fanaticism. He par.....
» 5/07/2014 5:36:15 AM . Dear Yuyutsu, . You wrote : « When one bases one's faith on material or historical f.....
» 3/07/2014 6:35:15 AM . Dear ORIGINS OF MAN, . You wrote : « Go ahead and kill me......I have a BCC cancer.......
» 2/07/2014 11:09:14 PM . Dear George, . You wrote : « I do not understand how you relate the distinction betw.....
» 1/07/2014 10:42:00 PM . Dear George, . Thank you for your comments. It’s amusing to see that you already stud.....
» 1/07/2014 10:35:50 PM . Dear Yuyutsu, . You wrote : « A man of faith should not waste their time and eff.....
» 1/07/2014 1:48:18 AM . Dear George, . You wrote : « … “Holding the view”, “most certain sign” etc are n.....
» 30/06/2014 11:31:44 PM . Dear Is Mise, . You wrote : « I thought that the concept of the Judeo-Christian-Isla.....
» 30/06/2014 11:42:09 AM . Dear Ojnab, . You wrote : « I thought that the concept of the Judeo-Christian-Islami.....
» 30/06/2014 11:24:54 AM . Dear George, . You wrote : « The Catholic Church does not “present” these things (mi.....
» 30/06/2014 1:20:37 AM . Dear Ojnab, . You wrote : « … why want a Catholic miracle to take place … » There i.....
» 29/06/2014 10:15:21 PM . Dear One Under God, . « AND HERE WE ART/still dividing/riPPING OTHERS CREATIONS..appa.....
» 29/06/2014 12:49:27 AM . Dear George, . I agree . Dear One Under God, . … The sea has many voices, Many god.....
» 28/06/2014 10:18:40 PM . Dear George, . You wrote : « Do you mean to say that a “miraculous healing” should b.....
» 28/06/2014 10:16:45 AM . Dear George, . I think we are basically saying the same thing. Your common sense is s.....
» 28/06/2014 2:37:31 AM . Dear George, . http://en.wikipedia.org/wiki/Lourdes_Medical_Bureau . Thanks for t.....
» 27/06/2014 7:03:17 AM . Dear George, . You wrote : « Vatican does not ask medical professionals to conclude .....
» 27/06/2014 6:14:45 AM . Dear George, . You wrote : « I think “spontaneous remission” refers to the case wher.....
» 27/06/2014 2:41:23 AM . Dear Yuyutsu, Matthew S and Foxy, . Perhaps I should add that the « to bind fast » of.....
» 27/06/2014 1:27:27 AM . Dear Yuyutsu & Matthew S, . Yuyutsu wrote : « … the word 'religion' comes from the L.....
» 26/06/2014 1:39:59 AM . Dear George, . You wrote : « In my understanding, spontaneous remission (an unexp.....
» 25/06/2014 9:19:08 AM . Dear George, . I agree : “errors of diagnosis” are probably less likely than “spontan.....
» 25/06/2014 1:35:26 AM . Dear George, . Thank you for that delightful story about the pious train driver and t.....
» 25/06/2014 12:56:55 AM . (Continued ...) . The Vatican created the Pontifical Academy of Sciences in 1603. In .....
» 25/06/2014 12:48:52 AM . Dear Is Mise, . Thank you for those detailed descriptions of Lourdes miracles N° 61 a.....
» 23/06/2014 10:22:34 PM . Dear Is Mise, . You wrote : « I would be very interested to see a scholarly refutati.....
» 23/06/2014 1:14:58 AM . (Continued ... ) . That may be true but I suspect that faith is not dependent on a vi.....
» 23/06/2014 1:12:33 AM . Is Mise wrote : « You really need to read up on miracles, the Church and Lourdes. Mira.....
» 22/06/2014 1:14:44 AM . Dear one under god, . You wrote: « THE WRITINGS SAY IT SO MUCH BETTER THAN I » I be.....
» 21/06/2014 7:55:22 PM . Dear Is Mise, . Attributing scientifically inexplicable phenomena to a god is a perso.....
» 20/06/2014 12:22:28 AM . Dear Ralph Seccombe (the author here), . Thank you for that interesting résumé of Bri.....
» 20/05/2014 12:48:19 AM . Dear Rachael, . Rape is forceful, non-consensual sexual intercourse. The Supreme Co.....
» 10/05/2014 8:25:15 PM . Dear one under god, . You wrote : « wHAT CAME FIRST THE CHICKEN..OR THE EGG? [CHICKE.....
» 10/05/2014 2:41:01 AM . Dear George, . You wrote to david f. : « I agree that religion can easily (and unfor.....
» 9/05/2014 8:12:33 AM . Dear Yuyutsu, . Thank you for your input. I can see where you are coming from but yo.....
» 9/05/2014 7:45:10 AM . Dear George, . I wrote: "Belief is an idea. It is the idea that something is tr.....
» 8/05/2014 8:33:31 PM . Dear George & Sells, . Belief is an idea. It is the idea that something is true. An i.....
» 8/05/2014 2:58:01 AM . (Continued ...) . "The end of Ideology", (the title of the article under di.....
» 8/05/2014 2:02:08 AM . The author wrote ... . « Ideology is the conviction that history may be changed by id.....
» 22/04/2014 9:28:06 PM . Peter’s monthly message in 4 easy steps … . 1. " … god, who is an idol of o.....
» 19/04/2014 10:51:51 PM . Dear david f. & One Under God, . Thank you, One Under God, for that spectacular pyrot.....
» 19/04/2014 8:09:26 AM . Dear One Under God, . Thanks for making the effort. Tradgedies are part of life, but.....
» 19/04/2014 3:16:32 AM . Dear One Under God, . You wrote : « i tried hard to HATE EVIL I TRIED HARD TO HATE S.....
» 18/04/2014 8:57:22 PM . Dear One Under God, . You wrote : « THE BIBLE EXTENSIVLY CAUTIONS US AGAINST JUDGING.....
» 17/04/2014 10:05:29 PM . Dear George, . You wrote : « The mass killing of innocent people is bad by any m.....
» 16/04/2014 6:52:27 PM . Dear George, . What you wrote previously was: “All that Butterfield claims … is that.....
» 15/04/2014 10:01:32 PM . Dear George, . You wrote: « I thought we already agreed to let Butterfield rest in p.....
» 14/04/2014 10:45:05 PM . Dear George, . You wrote to david f. : « In the Middle Ages doctors amputated leg.....
» 13/04/2014 10:55:35 PM . (Continued …) . Matthew, whose real name was Levi son of Alpheus, is reported to have.....
» 13/04/2014 9:09:38 AM . (Continued ...) . However, while it is understandable that the Catholic church hesita.....
» 13/04/2014 9:03:53 AM . Dear david f., George & One Under God, . Given the psychiatric case history of Sau.....
» 12/04/2014 10:16:52 PM . Dear George, . You wrote: " ... a respectable professor of mathematics would ha.....
» 12/04/2014 8:25:22 AM . Dear George, . You wrote : « … you favour Keynon, I favour Butterfield. » I do not .....
» 12/04/2014 12:15:53 AM . (Continued …) . Another of his peers, J.H.Hexter, an American historian, specialist i.....
» 12/04/2014 12:13:57 AM . Dear George, . You wrote : “My reservations were not about critical thinking but.....
» 11/04/2014 8:57:19 AM . Dear George, . You wrote : “… if I am not as keen to proclaim a scientist’s or other.....
» 11/04/2014 3:18:57 AM . Dear George, . You wrote : “From what I understand about history, including my own p.....
» 11/04/2014 12:00:23 AM . (Continued ...) . You also wrote: “I am afraid it still does trespass against the qu.....
» 10/04/2014 11:42:24 PM . Dear George, . You quoted Herbert Butterfield’s warning: “The study of the past with.....
» 10/04/2014 7:23:42 AM . Dear david f., George & AJ Philips, . The word « evil » is not part of my vocabulary......
» 9/04/2014 8:18:13 PM . Dear One Under God, . I am inclined to conclude that Saul’s conversion to Christianit.....
» 9/04/2014 2:55:15 AM . (Continued ...) . A symptom of chronic psychotic illness is to be found in 1 Corinthi.....
» 9/04/2014 2:45:31 AM . Dear david f. & One Under God, . A psychoanalysis of Saul nearly 2000 years in hin.....
» 8/04/2014 8:57:11 AM . Dear david f., . The oldest known list of New Testament books, known as the Muratoria.....
» 7/04/2014 8:59:19 AM . Dear david f., . Yes David, I suspect there are a number of discrepancies and contrad.....
» 7/04/2014 1:05:47 AM . Dear david f. & One Under God, . Referring back to my previous post regarding the sur.....
» 5/04/2014 1:08:57 AM . Frying Pan's Theology : . Scene : On Monaro. Dramatis Personae : Shock-headed black.....
» 4/04/2014 12:44:34 AM . Dear One Under God, . Many thanks for your kaleidoscopic commentary which I thoroughl.....
» 3/04/2014 12:39:26 AM . Dear One Under God, . Thank you for those literary references to “silly mathematics” .....
» 2/04/2014 2:33:31 AM . Dear George, . Thanks once again for your explanations which, I assure you, are alway.....
» 2/04/2014 12:18:03 AM . Dear David, George, & JKUU, . George wrote : « Actually, it is worse than that. .....
» 1/04/2014 6:37:38 PM . Dear david f., . Thank you for your brief explanation of Boolean algebra. I thought t.....
» 1/04/2014 9:54:57 AM . Dear George, . Thanks for the explanation. So it was a “lapsus clavis” (slip of the k.....
» 1/04/2014 12:31:49 AM . Dear George, . You first wrote : “ Actually, it is worth than that. I get 1 = 1+1+1+.....
» 31/03/2014 11:26:14 PM . Dear david f. and George, . David wrote : “My understanding of monotheism is tha.....
» 31/03/2014 4:25:31 AM . Dear david f. and George, . I was hoping George would come up with the solution to.....
» 30/03/2014 8:06:27 AM . Dear david f., . Allow me to suggest that the Trinitarian doctrine of Christian monot.....
» 30/03/2014 3:52:56 AM . Dear david f. . It’s nice to catch up with you again. I found the article on the .....
» 29/03/2014 1:09:16 AM . I still have a vivid memory of my visit, as a boy, to my home-town slaughter yards and .....
» 28/03/2014 12:05:51 AM . (Continued ...) . For Native Americans it is the “Great Spirit” and for Christians, t.....
» 27/03/2014 11:56:39 PM . Dear One Under God, . You wrote: [banjo..my present/thoughts..are led by conscio.....
» 26/03/2014 11:28:03 PM . Dear One Under God, . Thank you for your detailed analysis of my post to Squeers. Yo.....
» 25/03/2014 9:52:41 PM . Dear Squeers, . You wrote : … “ these (the concept of a creator, supreme being, God,.....
» 24/03/2014 11:51:46 PM . Dear George, . I am glad we agree to agree. Thank you for your explanations. I shal.....
» 24/03/2014 8:57:30 AM . Dear George, . You wrote : « Neither is it a fact that there is nothing beyond what .....
» 23/03/2014 9:07:33 PM . Dear George, . You wrote : [ >>The mystic thinks he is looking at God, but .....
» 23/03/2014 8:24:06 AM . Dear Ojnab, . I have been to several funerals here in Paris where there was no religi.....
» 23/03/2014 8:19:52 AM . Dear George, . You wrote : “ Mysticism, contemplation, meditation is not about f.....
» 22/03/2014 10:52:57 AM . Dear One Under God, . The last two funerals I went to here in Paris were both Catholi.....
» 22/03/2014 10:44:07 AM . Dear George, . You wrote: "Where did I write about IMAGINING (as distinct from .....
» 22/03/2014 2:53:13 AM . Dear George and Ojnab, . You are right, we should get back to the subject in hand .....
» 22/03/2014 2:43:57 AM . Dear George, . You wrote: "So you are right that mysticism as such refers nor .....
» 21/03/2014 4:59:50 AM . Dear Ojnab, . You wrote: “I really do not know if it just me but One Under God c.....
» 21/03/2014 2:54:24 AM . Dear Foxy, . I inadvertently attributed the coining of the terms “sociology” and “al.....
» 21/03/2014 2:23:53 AM . (Continued ...) . The Online Etymology Dictionary indicates (for imagination): ".....
» 21/03/2014 2:16:08 AM Dear George, . I prefer “godless Christian” to Dawkins’ “cultural Christian” because it.....
» 19/03/2014 8:59:59 PM . Dear One Under God, . I am deeply honoured to see that you have accepted my propositi.....
» 19/03/2014 11:35:29 AM . Dear Yuyutsu, . You recommended to me on page 10 of this thread: “ come to know that .....
» 19/03/2014 10:16:37 AM . Dear One Under God, . Thank you for that link to what somebody considers to be my .....
» 19/03/2014 10:04:31 AM . Dear George, . You wrote : “ … in some context you would like to know whether a pe.....
» 18/03/2014 3:57:08 AM . Dear Yuyutsu, . Thank you for your words of wisdom. As I just wrote to George, I d.....
» 18/03/2014 2:38:44 AM . Dear George, . As I am sure you will have understood, the « labelling » or « brand.....
» 18/03/2014 2:34:01 AM . Dear Runner, . Thank you for your opinion which is a pretty good photographic nega.....
» 17/03/2014 9:03:57 AM . What does it take to be a Christian ? . I was circumcised and baptised shortly after .....
» 16/03/2014 6:25:20 AM . Dear George, . It’s nice to hear from you once again. As far as I can recall, at .....
» 16/03/2014 12:01:09 AM I too have thrown off the shackles, lifted the veil of ignorance and seen the light. I had.....
» 15/03/2014 2:04:57 AM . We buried old Bob where the bloodwoods wave At the foot of the Eaglehawk; We fashioned.....
» 14/03/2014 10:42:19 AM . Dear Peter, . I think there is a basic misunderstanding here as to why people choose .....
» 11/02/2014 3:25:13 AM . Dear James, . The environmental sciences, including climatology, are noble pursuits, .....
» 25/12/2013 11:58:49 PM . Thank you all for those interesting insights into your early life. So I too am willin.....
» 9/12/2013 8:54:41 AM . Mandela was a Methodist. He told the Parliament of the World’s Religions in 1999. “With.....
» 8/12/2013 8:04:06 PM . Mandela was a Methodist. He told the Parliament of the World’s Religions in 1999. “With.....
» 8/12/2013 4:53:07 AM . It seems to me appropriate, at this point, to pause for a moment and hail the departure.....
» 7/12/2013 1:22:13 AM . Dear onthebeach, . Your statistics are interesting but a bit outdated. Perhaps you mi.....
» 7/12/2013 12:51:05 AM . Dear Suseonline, . There is no doubt women are more often victims than perpetrators w.....
» 29/10/2013 10:37:23 PM . Dear Yuyutsu, . You wrote: “My authority to live my life does not arise from this or.....
» 29/10/2013 6:26:40 AM . Dear individual and Yuyutsu, . The Magna Carta laid the foundation stone of all futur.....
» 29/10/2013 6:14:26 AM . . Dear Rhrosty, . Your two points are well taken. I agree not only that like all.....
» 19/10/2013 12:09:39 AM . Dear Graham, . The possibility to use bold, italics and underlyning would be useful. .....
» 18/10/2013 3:12:04 AM . Dear David, . Montaigne also said this: « I speak the truth not so much as I would,.....
» 18/10/2013 2:02:18 AM . Dear George, . I’m afraid there’s something of a Don Quijote de la Mancha in me. Howe.....
» 17/10/2013 7:01:50 AM . Dear George, . « So - returning to my analogy with me doing mathematics and having a .....
» 17/10/2013 5:58:27 AM . Dear David, . « I don’t argue with facts. The fact is that there are competent scient.....
» 16/10/2013 8:59:44 AM . Dear David & George, . David wrote : « I don’t think free will is a matter that can .....
» 16/10/2013 7:44:09 AM . Dear George, . I wrote : «I don’t think it is unreasonable to consider that “being a.....
» 15/10/2013 11:20:28 PM . Dear David, . I wrote: « Anybody who is an inconsistent believer is a part time beli.....
» 15/10/2013 8:36:51 AM . Dear George, . « In my understanding, free will is an important concept but it is not.....
» 15/10/2013 2:16:20 AM . Dear David, . « I personally think being a scientist is inconsistent with believing i.....
» 15/10/2013 1:12:25 AM . Dear One Under God, . [ banjo..<<>.on/the..basis of..the current..state/of t.....
» 14/10/2013 10:52:55 PM . Dear Davcid, . « Since the great scientist, Isaac Newton, believed in God it is obvio.....
» 14/10/2013 7:55:36 AM . Dear David, . [«Is being a scientist compatible with believing in God?» is the title .....
» 13/10/2013 1:17:28 AM . To close this chapter of popular French songs ... . Jean Ferrat : http://www.youtube.....
» 12/10/2013 1:08:12 AM . (Continued) ... . In Paris, he had to find a hideout, but he knew very few people. Fi.....
» 12/10/2013 12:46:45 AM . Georges Brassens, . During his lifetime (22 October 1921 – 29 October 1981) Georges B.....
» 11/10/2013 6:36:11 AM . Dear David, . “ That reminds me of a French short story. A women had four husbands wh.....
» 10/10/2013 9:32:15 AM . (Continued) ... . Another song she wrote "Göttingen" (named after the Germa.....
» 10/10/2013 9:27:56 AM . Barbara, . George : “ For many Edith Piaf continues to live on ...” Edith Piaf had.....
» 9/10/2013 2:08:58 AM . (Continued) ... . The love of Piaf's life, the married boxer Marcel Cerdan, died in a.....
» 9/10/2013 2:04:08 AM . Edith Piaf, . Today, the 10th October 2013, is the 50th anniversary of the death of F.....
» 5/10/2013 8:18:23 PM . To poets all, . LET us cease our idle chatter, Let the tears bedew our cheek, For a .....
» 3/10/2013 7:09:01 PM . (Continued) ... . Immortality of the soul is a Greek notion formed in ancient mystery.....
» 3/10/2013 7:06:28 PM . Dear David, . Your posts are quite remarkable. I should have liked to have signed the.....
» 3/10/2013 4:30:30 AM . Dear George, . [>>Who could doubt that science has its limitations (your expert.....
» 2/10/2013 6:49:50 PM . One Under God, . I wrote: “Don’t worry, George, I won’t be offended if god does not .....
» 2/10/2013 7:32:19 AM . Dear George, . « So my metaphor about walking did not convey to you what I thought it.....
» 30/09/2013 8:19:00 PM . (Continued) ... . “… you still have not suggested what you would want that god do to .....
» 30/09/2013 8:12:05 PM . Dear George, . [ I certainly do “leave science a free hand to carry out whatever inve.....
» 30/09/2013 8:20:14 AM . Dear David & One Under God, . The oldest known literary texts date from the 27th or 2.....
» 28/09/2013 11:46:19 PM . Dear David, . “The God of the Bible makes playthings of us. We enact scenarios that H.....
» 28/09/2013 7:48:54 AM . Dear George, . « What restriction? In my view the assumption that science can explai.....
» 28/09/2013 3:10:49 AM . Dear George, . I replied to your question in my previous post : “Proof or evidence o.....
» 27/09/2013 6:53:24 AM . (Continued)... . None of this is specific to our present discussion. I have no des.....
» 27/09/2013 6:48:24 AM . Dear George, . [ >>I consider that the restriction you propose is “void ab init.....
» 25/09/2013 10:10:41 AM . (Continued) ... . Ideas and sentiments exist. They are integral elements of various l.....
» 25/09/2013 10:01:47 AM . Dear George, . [ >>This statement presumes the existence of the supernatural.&l.....
» 25/09/2013 3:20:54 AM . Dear George, . « What I was suggesting was, that this meeting of the "natural&qu.....
» 24/09/2013 6:17:06 PM . Dear David, . « I think the analogy of languages to a tree with branches and roots is.....
» 22/09/2013 10:57:42 PM . Dear George, . “So we are back to square one as to the noun corresponding to credere .....
» 22/09/2013 8:48:58 PM . Dear George, . « I thought credo - like in “credo in unum Deum” - referred only to th.....
» 21/09/2013 7:39:26 PM . Dear One Under God, . [ “I see clearly,” the pope continues,..“that the thing the chu.....
» 21/09/2013 7:36:47 PM . Dear David, . « I am sorry, oug. I apologise to George, Banjo and any others who may .....
» 21/09/2013 7:52:05 AM . Dear George, . « Thanks, so there are ten different French/English possible translati.....
» 21/09/2013 6:10:28 AM . Dear David, . How right you are. Words out of context can be incorrectly interpreted .....
» 20/09/2013 8:02:34 AM . Dear George, . Unfortunately, I do not have an English/Latin dictionary. I happen to .....
» 19/09/2013 11:56:16 PM . Dear George, . " … In Latin they have fides for faith (that apparently gave rise.....
» 19/09/2013 10:42:54 PM . (Continued) … . They groaned, they stirred, they all uprose, Nor spake, nor moved the.....
» 19/09/2013 10:33:43 PM . To whom it may concern . "A religion, that is, a true religion, must consist of .....
» 18/09/2013 10:07:43 PM . Dear David, . « I am bothered by the careless use of language but am guilty of it mys.....
» 17/09/2013 10:44:51 PM . Dear David, . “Since I was not using the word, faith, to refer to the attitude into w.....
» 17/09/2013 7:33:11 PM . Dear David, . « To understand what a word means we have to know what it meant at the .....
» 17/09/2013 7:45:09 AM . (Continued) ... . It is only when the insured makes a claim on his policy due to the .....
» 17/09/2013 7:36:33 AM Dear David, . « Etymology tells us the source of a word. It does not tell its meaning. M.....
» 15/09/2013 11:42:27 PM . Dear David, . “I think faith in itself is not worth a pail of warm spit. I think fait.....
» 14/09/2013 12:15:57 AM . (Continued) ... . These opinions were in relation to mine which I expressed initially.....
» 14/09/2013 12:00:08 AM . Dear One Under God, . Thank you for that enlightening insight to your character, pers.....
» 13/09/2013 12:36:42 AM . Calling One Under God … . come in One Under God … do you read me? over ! bingo par.....
» 12/09/2013 8:41:02 AM . Dear George, . You wrote: [The three little pigs: After they learned their lesson, .....
» 11/09/2013 11:11:20 PM . Dear George, . You wrote: [ “But, as George’s father seems to have taught him when h.....
» 10/09/2013 11:59:36 PM . Dear David & George, . « The evil in the Bible continues in the New Testament. An arb.....
» 10/09/2013 2:53:09 AM . Dear David, . “ We feel better if we accept responsibility ...” . Perhaps that’s why.....
» 9/09/2013 8:53:52 AM . Dear David, . [ One of my favorite quotes is: “If only it were all so simple! If on.....
» 8/09/2013 5:39:26 AM . Dear David et al, . Roses ruddy and roses white, What are the joys that my heart dis.....
» 6/09/2013 10:10:57 PM . Dear David, . « You may not be allergic to daffodils. Typically pretty flowers like d.....
» 5/09/2013 8:52:07 PM . Dear David, . « Why make a hierarchy at all? Why not just enjoy the beauty of both. D.....
» 5/09/2013 7:32:02 AM . (Continued) ... . So it seems there are no such things as circles, straight lines, tr.....
» 5/09/2013 7:15:47 AM . Dear David & One Under God, . “Don’t sell yourself short, Banjo. I am sure you could .....
» 4/09/2013 6:41:51 AM . Dear George, . Thanks for your comments which I find enlightening as always. . [>.....
» 3/09/2013 11:16:53 PM . (Continued) ... . “G. H. Hardy, Daniel J. Cohen, George, et al.” . A major figure of.....
» 3/09/2013 11:13:31 PM . Dear David, . « I’m sure that George, OUG, you and I all see beauty in this world, al.....
» 3/09/2013 8:51:17 AM . Dear George, . I have no problems with your last post which I had not read before pos.....
» 3/09/2013 1:28:44 AM . Dear David, . Looks like I got in wrong again ... but not completely. If I read you.....
» 2/09/2013 7:37:28 PM . Dear David & George, . Thank you both for your explanations which lead me to modify m.....
» 2/09/2013 2:08:18 AM . Dear One Under God, . Re: YouTube video of superhuman Shaolin monk. Recourse to magi.....
» 2/09/2013 1:12:50 AM . Dear George, . Thank you for the link to that interesting piece by Bill Meacham entit.....
» 31/08/2013 8:03:48 AM . Dear George, . « ... one cannot judge Chinese philosophy, way of thinking, from folkl.....
» 29/08/2013 6:56:52 PM . Dear David, . « Human concepts are inherent in nature because humans are a part of na.....
» 29/08/2013 9:55:45 AM . Dear David, . Yes, all that you relate can be found in nature and is quite amazing. .....
» 29/08/2013 9:40:39 AM . Dear George, . « if you see Yin and Yang as “forces” you can add a third one to them,.....
» 29/08/2013 8:31:06 AM . Dear David, . Thank you for that excellent scientific briefing on Newton’s third law .....
» 28/08/2013 6:34:35 AM . Dear George, . « Phew, I am not sure I made myself comprehensible.” . It does sound .....
» 27/08/2013 6:09:35 PM . Dear David, . “Duality is not observed in nature. Human perceptions give nature a dua.....
» 27/08/2013 2:03:52 AM . Dear David, George and One Under God, . It is not surprising that the duality observe.....
» 25/08/2013 9:57:08 PM . (Continued) . David: “ The periodic table does not demonstrate the number of natural .....
» 25/08/2013 9:53:23 PM . Dear David and George, . George: « I don't see faith as opposed to bigotry. I see big.....
» 25/08/2013 5:26:28 AM . (continued) . The Chinese apply the principle of natural duality to many aspects of t.....
» 25/08/2013 5:18:49 AM . Dear David, . “ Banjo has muddied the waters by bringing in bigotry.” . Sorry about.....
» 23/08/2013 10:26:07 PM . Dear David, . “Your semantics are exquisite, but I am not anti-semantic.” . Don’t w.....
» 23/08/2013 10:12:53 PM . Dear George, . « Godless faith sounds to me - forgive my language - as a kind of spir.....
» 23/08/2013 8:31:40 AM . Dear George, . « I think by “faith without god” you mean what is more commonly known .....
» 23/08/2013 7:06:12 AM . Dear David, . « … as far as I am concerned leaps of faith which spring from acceptanc.....
» 22/08/2013 7:57:19 PM . Dear George, . « Many a deeply religious person would say exactly the same thing, exc.....
» 22/08/2013 12:52:55 AM . Dear George, . Thanks for the link to the BBC transcript of the “God on the Brain” re.....
» 19/08/2013 8:20:34 PM . Dear George, . I have just returned from a trip to Australia and take up from where I.....
» 24/07/2013 6:22:05 PM . Dear one under god, . « i know science..can lead to proof of god..that’s where i bega.....
» 24/07/2013 5:12:12 AM . Dear George, . If I have understood you correctly, your personal opinion is that scie.....
» 23/07/2013 6:57:21 AM . Dear George, . No doubt awareness (consciousness) and autonomy (free will) coexist wi.....
» 21/07/2013 10:37:29 PM . Dear George, . « … phenomena that a theist sees as miracles or divine acts, are natur.....
» 21/07/2013 8:12:31 AM . Dear George, . « ... if you believe that reality that science has access to is all re.....
» 20/07/2013 8:39:50 AM . Dear George, . I appreciate your interest in this topic and your endeavours to come t.....
» 12/06/2013 8:14:43 PM . Dear Pericles and Yuyutsu, . The king's a beggar, now the play is done: All is well e.....
» 12/06/2013 3:40:03 AM . (Continued ) . Yuyutsu: "God is not a deity ... God is neither supernatural nor .....
» 12/06/2013 3:29:41 AM . Dear Pericles and Yuyutsu, . Pericles wrote: "Is it important to you, that you .....
» 11/06/2013 7:33:21 AM . (Continued ...) . It also means that your goal in life is to become one with God, or,.....
» 11/06/2013 12:22:56 AM . Dear Yuyutsu, . You wrote: "Belief has to do with the world ... ". Faith h.....
» 10/06/2013 8:58:09 AM . Dear Yuyutsu, . I wrote in my last post: "I am afraid this is esoteric langu.....
» 10/06/2013 6:52:37 AM . Dear George and Yuyutsu, . Thank you for your links, George. I find them quite intere.....
» 10/06/2013 5:22:44 AM . Dear George and AJ Philips, . Belief and faith are largely interchangeable but there .....
» 9/06/2013 11:23:21 PM . Dear Yuyutsu, . You indicate: "Firstly, it's not about "loving a God".....
» 8/06/2013 1:25:10 AM . Dear Grateful, . Welcome back. "However, the real issue is whether there is a r.....
» 7/06/2013 11:05:46 PM . Dear AJ Philips, . George and I had a discussion on what is meant by "faith".....
» 7/06/2013 8:42:21 PM . Dear Yuyutsu, . You wrote: ["All love that is contingent upon something, when t.....
» 6/06/2013 9:26:08 PM . Dear Yuyitsu, . You wrote to George: "Would you still love your wife when she g.....
» 5/06/2013 8:48:01 PM . Dear Poirot, . "Why did you quote "high schools" and then go on to cal.....
» 5/06/2013 9:02:07 AM . Dear Suseonline & Yuyutsu, . Recent research reveals that unlike that of many other b.....
» 5/06/2013 12:45:03 AM . Dear Poirot, . "3 high school students suicide every week in Australia. Why are .....
» 4/06/2013 11:38:24 PM . Dear Yuyutsu, . "why is belief that important?" . As Richard Feynman (Nobe.....
» 4/06/2013 8:19:53 PM . Dear Suseonline, . "No one has proof of actually seeing a God, and we only have .....
» 4/06/2013 8:36:03 AM . Dear Suseonline, . "What are you called if you believe in multiple Gods?" .....
» 4/06/2013 7:57:00 AM . Dear grateful, . You wrote: "Personally, I think your response actually reinfor.....
» 4/06/2013 12:07:48 AM . (Continued ...) . It was the French sociologist, Emile Durkheim, who first suggested .....
» 3/06/2013 11:46:01 PM . Dear grateful, . In my previous post I was referring to morality as the "conform.....
» 3/06/2013 12:54:10 AM . Dear grateful, . You observe: ["What I would say is that if there is such a thi.....
» 3/06/2013 12:49:13 AM . Dear grateful, . As Richard Feynman (Nobel prize in physics, 1965) is reported to hav.....
» 31/05/2013 6:02:12 AM . Dear grateful, . You wrote: "....How we experience life and death ...with humil.....
» 31/05/2013 1:22:36 AM . Dear grateful, . Thank you for introducing me to the 13th-century Persian poet, juris.....
» 29/05/2013 7:24:19 PM . I know why Shira ain't around And even why she can't be found Not much good just waitin.....
» 28/05/2013 9:01:46 PM . Looking for Shira ... . Now look, you see, it's this way like, You cross the broken b.....
» 28/05/2013 7:52:38 AM . ... and something a little more spiritual ... . http://www.youtube.com/watch?v=9mrVZH.....
» 28/05/2013 2:57:05 AM . To all & sundry, . A light musical interlude with some of my favourites ... http://w.....
» 28/05/2013 1:34:33 AM . Dear grateful, . Let us cease our idle chatter, . Let the tears bedew our cheek, Fo.....
» 27/05/2013 6:37:02 AM . (Continued ...) . The most plausible explanation of the genesis of life appears to ha.....
» 27/05/2013 6:30:17 AM . Dear grateful, . You wrote: "Freedom in its true sense requires an act of creat.....
» 26/05/2013 10:37:52 AM . Dear Grateful, . You seem to deduce from my previous posts that I am an atheist. I ha.....
» 25/05/2013 11:11:21 PM . Dear Jay Of Melbourne, . You wrote to Suseonline: "Watch the video, it makes se.....
» 25/05/2013 7:14:04 AM . To all & sundry, . Apparently many posters here ignore the results of recent zoologic.....
» 24/05/2013 8:14:27 PM . Dear Shira, . Though your silence is gold ... a little philosophy can't do any harm ......
» 24/05/2013 6:19:00 PM . Dear Shira, . Perhaps a musical comedy from some of my creepy fossil friends (who, li.....
» 23/05/2013 8:34:58 PM . Dear Shira, . Death is not a problem for the dead, it is a problem for the living. T.....
» 23/05/2013 7:20:43 AM . Dear Shira, . As I see it, it makes no difference, so far as your father is concerned.....
» 22/05/2013 6:51:54 AM . . Dear David, . That's a great show. I enjoyed that. Thanks. Sounds like you have h.....
» 22/05/2013 2:06:46 AM . Dear David, . "Jesus Christ was a Jew not a Christian. His followers reject his .....
» 21/05/2013 11:11:05 PM . Dear Producer and Tony Lavis, . Sheeple, astrology and intelligent design do, indeed,.....
» 21/05/2013 8:41:36 PM . Dear David, . "Wise poker players and urinal raisers limit their raises. That's .....
» 21/05/2013 8:07:20 PM . Dear David, . You wrote: "Islam was not originally a missionary religion. Earl.....
» 21/05/2013 6:37:39 PM . Dear David, . You ingeniously suggest: "To keep men on their toes, raise the ur.....
» 21/05/2013 6:36:40 AM . Dear praxidice, . You wrote: "Whilst you clearly don't acknowledge the existenc.....
» 21/05/2013 4:50:01 AM . Dear david f, . "You referred to Orwell's dystopian novel. The novel described a.....
» 20/05/2013 8:06:03 PM Dear praxidice, . You wrote: "As I've said previously, Darwinian evolution & intel.....
» 20/05/2013 7:32:07 AM . Dear david f, . Thanks for that interesting link. John Paul II was the first and, fo.....
» 20/05/2013 12:53:53 AM . To all and sundry, . The battle for the minds of children moved into top gear 23 year.....
» 19/05/2013 9:13:26 AM . Dear praxidice and Shockadelic, . I think david f has raised a valid point which is p.....
» 18/05/2013 7:33:07 PM . Dear individual, . Well that's not actually the full story. I have, in fact, bought .....
» 18/05/2013 2:44:32 AM . Dear praxidice, . As I live in Paris, whenever I feel the need to contact a member of.....
» 17/05/2013 5:36:20 AM . Dear david f, . All countries are multicultural to some extent. Some more than others.....
» 12/05/2013 12:42:46 AM . ... and this: . The broad-backed hippopotamus Rests on his belly in the mud; Alth.....
» 11/05/2013 9:03:46 PM . Dear david f, Tony Lavis and WmTrevor, . I am glad to see I am in such good company ......
» 11/05/2013 3:54:04 AM . Recourse before the French Constitutional Court . For those who understand French or .....
» 11/05/2013 1:13:05 AM . Dear phanto, . You wrote: "The only reason people want government sanction of t.....
» 10/05/2013 10:07:53 PM . Dear Saltpetre, . The problem is we have been conditioned for so long by our social a.....
» 9/05/2013 11:59:15 PM . Dear david f, . You wrote: "Very few parents have more than one sex. Ursula le .....
» 9/05/2013 10:28:55 PM . Dear praxidice, . In Australia, a non-constitutional referendum is usually called a p.....
» 9/05/2013 7:03:36 AM . Dear Saltpetre, . Since you want the stats served to you on a platter: - There were .....
» 9/05/2013 12:25:23 AM . Same sex marriage: some facts and figures . The Netherlands became the first country .....
» 8/05/2013 10:20:58 PM . Dear Brendan (O’Reilly, the author), . I think your article could form the basis of a.....
» 6/05/2013 11:14:29 PM . Dear Constance, . You wrote: "Now don’t get too laid back now, will you?" .....
» 6/05/2013 7:15:17 AM . Dear Constance, . You wrote: "You don’t seem to understand, I think you are unw.....
» 5/05/2013 6:57:19 AM . Gender selection by In vitro fertilisation (IVF) . It seems that baby sex-selection t.....
» 5/05/2013 6:17:12 AM (Continued) ... . 'Here he comes, and for shame! ye've forgotten the name - Is it Patsy.....
» 5/05/2013 6:14:43 AM . Dear Suseonline, . "Religion, and religious men, no longer dominate our society......
» 5/05/2013 2:14:12 AM . Dear Constance, . You wrote: "Your admiration of Pericles says much ... " .....
» 4/05/2013 10:25:04 AM . Abortion & Morality . Science has no universally accepted clear-cut definition of whe.....
» 2/05/2013 8:15:06 AM . Dear Constance, . You also wrote: "I hear the French have become émigrés in abo.....
» 2/05/2013 1:49:50 AM . A brief interlude ... . So let's take the time to contemplate on a few basic facts: .....
» 1/05/2013 11:40:48 PM . Dear Constance, . You wrote: "Why on earth have you brought up Darwinism? I don.....
» 1/05/2013 5:08:19 AM . Dear Poirot, . You wrote: "Have you read Camille Paglia's "Sexual Personae.....
» 30/04/2013 9:14:44 PM . Dear Paul1405 & Tony Lavis, . Paul wrote: "Tony what is that about civics? Is n.....
» 30/04/2013 8:07:34 AM . Dear onthebeach & Poirot, . Your discussion reminds me an important aspect of the sub.....
» 29/04/2013 5:41:32 AM . Dear Jay Of Melbourne, . You wrote: [The goal of Globalisation is one global standar.....
» 29/04/2013 3:01:49 AM . Dear rehctub, . You wrote: "... married refers to the union of a man and woman.&.....
» 28/04/2013 12:07:45 AM . Dear Jay Of Melbourne, . You wrote: "Gay marriage is just a relatively benign p.....
» 27/04/2013 11:47:57 PM . Dear Luciferase, . You wrote: "The State, on the other hand, should stay out of.....
» 27/04/2013 9:12:27 PM . Dear Constance, . You wrote: "Here's some interesting insights in Der Spiegel r.....
» 27/04/2013 9:07:50 AM . Dear Mark (Christensen, the author), . You wrote: "The current political model .....
» 26/04/2013 8:43:05 AM . Dear Paul1405, . You wrote: "The Ratbag Religious Right in France put up a viol.....
» 25/04/2013 2:34:11 AM . Dear onthebeach, . If there's no problem, I guess there's no need to fix it. . Dear.....
» 24/04/2013 2:13:28 AM . Dear Josephus, . You wrote: " WHAT IS IT HOMOSEXUALS WANT BY MARRIAGE? ... (fol.....
» 23/04/2013 9:01:41 PM Dear Runner, . You wrote: [' According to historians, marriage evolved about 20,000 yea.....
» 23/04/2013 9:22:05 AM . Dear onthebeach, . You wrote: "It is hip to ... promote something that irks Ch.....
» 22/04/2013 11:21:56 PM . Dear Josephus, . You wrote: "The marriage ceremony and celebration contains man.....
» 22/04/2013 8:18:19 AM . Homosexuality & Marriage ... . The terms "homosexual" and "heterosexua.....
» 20/04/2013 8:40:09 PM . Dear Paul1405, . You wrote: "Just as I said, here we have Father Jo an authorit.....
» 20/04/2013 8:09:09 PM . Dear Josephus, . You wrote: " ... perhaps statistics on gays indicate loosely f.....
» 20/04/2013 8:23:58 AM . Continued ... . The track record of heterosexual marriages in Australia is extremely .....
» 20/04/2013 2:28:03 AM . Continued ... . Marriage is an oral contract imposing legal rights and obligations, p.....
» 19/04/2013 11:10:11 PM . Love and marriage ... . It is a common feature in the animal kingdom for males to com.....
» 16/04/2013 7:35:26 PM . At midnight in the museum hall The fossils gathered for a ball There were no drums o.....
» 14/04/2013 8:39:41 PM . Dear Yuyutsu, . I read the 84 Narada Bhakti Sutras which you indicated but found no r.....
» 13/04/2013 9:31:58 PM . Dear David G . "In our disposable world, there is little or no love that is tota.....
» 12/04/2013 11:12:24 PM . Dear Yuyutsu, . "Hate' needs no reference, it's an objectless, intransitive verb.....
» 12/04/2013 6:53:45 AM . Dear Yuyutsu, . I think you are referring to "the idea of god", whereas Pet.....
» 11/04/2013 11:54:12 PM . Dear Peter Sells, . I am surprised by your question "The meaning of life?" .....
» 31/03/2013 6:13:07 AM . Dear david f, . I always thought you were a bit odd, David ... a bit like me I suspec.....
» 31/03/2013 4:47:08 AM . Dear David f and George, . At the crossroads of religion and science, there is, of co.....
» 30/03/2013 9:39:20 AM . An Easter gift ... . I hope you enjoy it ... http://www.youtube.com/watch?v=es5fqw3w.....
» 29/03/2013 10:36:59 PM . Dear Yuyutsu, . "One possibility is that rather than dying, Jesus went into Sama.....
» 29/03/2013 5:04:50 AM . Dear George, . "We already had such talk-past-each-other encounter on another th.....
» 29/03/2013 2:12:09 AM . Dear Yuyutsu, . "Since you addressed me, may I ask what your point is?" As.....
» 28/03/2013 10:49:10 PM . Dear George and Yuyutsu,, . "Though throughout its history Christianity used to .....
» 27/03/2013 7:09:01 PM . Dear Yuyutsu, . "I can also envision this written in a book and subsequently, 60.....
» 27/03/2013 2:48:15 AM . Dear Yuyutsu, . [Everything that exists is an object and every object is limited. God.....
» 26/03/2013 3:58:31 AM . Dear Yuyutsu, . Thank you for your blessing. I wish you well, in return. Perhaps you.....
» 25/03/2013 8:56:37 AM . Dear Yuyutsu, . "Then you are well on your way to God. God bless you!" . T.....
» 24/03/2013 9:03:16 AM . Dear David G., . "Faith spreads despite a total lack of every single one of thes.....
» 23/03/2013 10:54:52 PM . Dear david f, . Thanks for the tip and the info. I had no idea paedophilia was so ba.....
» 23/03/2013 9:18:17 AM . Dear Yuyutsu, . I thought I should mention that I share your aversion of "insti.....
» 22/03/2013 9:16:05 PM . Dear Yuyutsu, . "I am sure the government itself sees me rather as nuisance, not.....
» 22/03/2013 2:04:15 AM . Dear Peter Sells, . "I must write a long essay on the failure of reason in defin.....
» 22/03/2013 1:14:04 AM . Dear mhaze, . G.K. Chesterton was a brilliant mind. He was known as "the prince .....
» 21/03/2013 10:39:26 AM . Dear David G, . "Religion does a great deal of harm ..." . That's a fairly.....
» 20/03/2013 7:29:34 PM . Dear GlenC, . I do not see which comment or post of mine you are referring to. All .....
» 20/03/2013 8:23:21 AM . Dear Yuyutsu, . Many thanks for your explanation of the prolixity of our dear friend,.....
» 19/03/2013 11:24:46 AM . Dear Peter, . I see you have written well over a hundred articles on Online Opinion, .....
» 17/03/2013 10:42:09 AM . Dear Ludwig, . That's a very noble profession. I love the bush but I'm afraid I don't.....
» 15/03/2013 10:25:18 PM . (continued ...) He fetched a wild up-country yell might wake the dead to hear, And tho.....
» 15/03/2013 10:23:46 PM . More on misunderstanding ... . It was the man from Ironbark who struck the Sydney tow.....
» 15/03/2013 1:04:30 AM . Dear George, . To sum up that rather lengthy discussion, I think it is safe to say th.....
» 14/03/2013 9:00:00 AM . Dear George, . "I have never heard of molecules being called “infinitely small” .....
» 14/03/2013 1:38:38 AM . Dear George, . "Sorry, but I really do not know what “"the smallest quantit.....
» 13/03/2013 11:12:29 AM . Dear George, . "There is no such thing as the smallest positive real number".....
» 12/03/2013 11:09:26 PM . Dear George, . [Here “the final value before zero” does not make sense. (Whatever posi.....
» 12/03/2013 7:56:50 AM . Dear George, . [>>“infinitely small” means the smallest quantity of something w.....
» 11/03/2013 4:02:55 AM . Dear George, . "I can understand what “very small” means, I have only problems w.....
» 10/03/2013 10:05:35 PM . Dear George, . I note that my "infinitely small" and David's "very fee.....
» 10/03/2013 8:59:23 AM . Dear csteele and George, . If you are talking about two particles in space where spac.....
» 8/03/2013 8:47:20 PM . Dear landrights4all, . All I can say is good luck, my friend, I wish you well. No ne.....
» 8/03/2013 4:29:49 PM . Dear landrights4all, . You wrote: "(Banjo – try that direct link)" I tried.....
» 8/03/2013 8:47:10 AM . Dear landrights4all, . We evidently have a communications problem. I have carefully .....
» 7/03/2013 10:36:36 AM . Dear ybgirp, . As I already wrote on page 7 of this thread, I confirm: "I agree.....
» 7/03/2013 10:23:29 AM . Dear landrights4all, . " ... up to half the unemployed in public housing might b.....
» 6/03/2013 10:19:12 PM . Dear Grim, . "The classic simple argument against democracy is 2 wolves and a la.....
» 6/03/2013 3:58:59 AM . Dear landrights4all, . " ... it is clearly untrue to say that there isn't enough.....
» 6/03/2013 2:13:54 AM . Dear Grim, . According to The Economist Intelligence Unit’s Index of Democracy 2011, .....
» 5/03/2013 10:05:52 AM . Dear Jardine K. Jardine, . Thanks for that. I see from the Aust. Govt. website that t.....
» 5/03/2013 3:10:05 AM . Dear landrights4all, . " I believe there is a way which is consistent with the .....
» 5/03/2013 1:42:37 AM . Dear Grim, . "I think a stronger adversarial system could be achieved with indep.....
» 3/03/2013 12:37:31 AM . Dear Grim and ybgirp, . When all is said and done, I can't help feeling that "tr.....
» 2/03/2013 3:48:07 AM . Dear ybgirp, . "Only a parliament of well-informed, genuine independents electe.....
» 1/03/2013 8:59:26 AM . Dear landrights4all, Pericles, ybgirp and Yuyutsu, . Though some idealists may have a.....
» 1/03/2013 3:23:50 AM . Dear David F., . "...one way to effect democratic change is for the states to ma.....
» 28/02/2013 12:43:19 AM . Our fragile Commonwealth ... . The Honourable the Premier, Campbell Newman MP has jus.....
» 26/02/2013 8:34:31 PM . Dear George, . Don't worry. I understand. In my ignorance, I didn't realize I had ask.....
» 26/02/2013 3:32:24 AM . To all and sundry, . The pope's recent resignation raises serious questions concernin.....
» 25/02/2013 11:21:46 PM . Dear David, George and Ludwig, . Many living species are capable of truth and deceit......
» 23/02/2013 7:40:19 PM . Dear David F, . "I have no idea why a lead pipe cinch should mean certainty.&quo.....
» 23/02/2013 12:32:56 AM . Dear David, George, and Ludwig, . Sorry to have taken so long to get back to you. Of.....
» 22/02/2013 5:06:57 AM . Dear David F . How right you are. Your grandfather spoke but he did not say anything......
» 22/02/2013 2:52:53 AM . Dear George, . [I think one must be careful not to confuse “truth” with “information”.....
» 21/02/2013 10:53:35 PM . Here is my understanding of truth . I see truth as information which has not been vol.....
» 21/02/2013 1:39:27 AM . Sorry, ... Education is \$21 million. ......
» 20/02/2013 11:36:27 PM . The Role of the Philanthropic Sector in Addressing Homelessness in Australia . An in.....
» 20/02/2013 9:26:16 PM . Dear Poirot, . As I pointed out in my last post to Squeers, mankind has been storing .....
» 20/02/2013 3:34:02 AM . Dear Nick, . Thank you for the link to the article on "Prosperity" in Wikip.....
» 20/02/2013 12:50:18 AM . Dear Nick, . I'm sorry but Turiel's demonstration is about as clear as mud to me. I .....
» 19/02/2013 3:36:54 AM . Daer Squeers, . Capitalism is a relatively recent term, coined in the mid-19th centur.....
» 19/02/2013 3:16:59 AM . Dear Poirot, . I'm afraid I'm not a fan of Andy Warhol and pop art. It tends to repul.....
» 18/02/2013 11:32:26 PM . Dear Nick, . Re: "The Twilight of Petroluem": Antonio Turiel, the author o.....
» 18/02/2013 11:55:13 AM . Dear Squeers, . "Capitalism is not merely trade and barter." . Agreed. &quo.....
» 18/02/2013 3:08:55 AM . Dear Poirot, . I can understand your passion for Claude Monet. Not only was he a gr.....
» 18/02/2013 1:44:43 AM . Dear Squeers, . I don't think you should give up - at least, not yet. I understand y.....
» 17/02/2013 10:14:04 AM . Dear Poirot, . "The exchange of anything in kind is a fundamental joy. I think, .....
» 17/02/2013 8:43:27 AM . Dear Squeers, . "You're thinking from within the mad logic of "economic rea.....
» 16/02/2013 7:12:50 AM . Dear Poirot, . The vegetables sound great. It seems you are almost self-sufficient. W.....
» 16/02/2013 3:43:25 AM . Dear Constance and Squeers, . Thanks for your link, Constance. I immediately recogniz.....
» 15/02/2013 2:09:51 AM . Dear Squeers, . I guess you can't blame philanthropists for all those egoists (who,.....
» 15/02/2013 1:52:02 AM . Dear Constance, . "Known for his frugality, Feeney flies coach class, owns neith.....
» 13/02/2013 8:52:23 PM Dear David G, . The time has come ... . So throw the weary pen aside And let the pap.....
» 12/02/2013 10:50:48 PM . French to ban bank speculation ... . The French socialist government of president Fra.....
» 12/02/2013 7:21:13 AM . Did you know? Australia is the most charitable (altruistic) nation in the world ! . A.....
» 11/02/2013 3:03:17 AM . Dear Poirot, . I hope you have recovered from that nasty throat problem. I must conf.....
» 10/02/2013 11:58:29 PM . Dear Grim and Squeers, . Squeers - "... I think Banjo Paterson, latterly, is ta.....
» 10/02/2013 11:58:44 AM . Dear Poirot, . Many thanks for the link to Vandana Shiva's lecture on Poverty and Glo.....
» 10/02/2013 9:59:23 AM . Dear Nick, . Thank you for your links, in particular, to the interview of the cellula.....
» 9/02/2013 10:12:47 PM . Dear WmTrevor, . I like your analogy of "blaming the petrol for the car that jus.....
» 9/02/2013 11:19:07 AM . Dear David G, Grim & Poirot, . I share your concerns regarding the deviations, abuses.....
» 9/02/2013 2:39:13 AM . Dear Grim, . "Capitalists hate competition. It gets in the way of acquiring Capi.....
» 7/02/2013 10:30:10 PM . Dear David G & Squeers, . Squeers - "apologies, I'm pressed and that is rather g.....
» 6/02/2013 11:54:34 PM . Dear Squeers, . You wrote to Pericles: "it [our co-operative system ] remains des.....
» 6/02/2013 4:13:25 AM . Dear Nick & Pericles, . This is an academic piece written by a Spanish sustainable de.....
» 5/02/2013 11:22:03 AM . Dear Squeers, . "You are mistaken" Just as well I asked. Forewarned is forea.....
» 4/02/2013 9:21:22 PM . Dear Squeers, . Biological computer science seems to be making some timid progress on.....
» 4/02/2013 10:22:29 AM . Dear Squeers, . "I appear to have given offence ... I'm sorry." You alone k.....
» 3/02/2013 10:14:38 PM . Dear David G . "What has Eisenstein's book brought to the table?" Though I.....
» 3/02/2013 8:51:14 AM . Dear David G, . "Whatever the case, I personally consider there are more effecti.....
» 2/02/2013 11:32:12 PM . Dear Squeers, . "You seem much more confident in your worldview and your grasp o.....
» 2/02/2013 10:34:07 AM . Dear David G, . I sympathise with you but I think you will agree that it is better to.....
» 1/02/2013 11:26:06 PM . Eisenstein's Sacred Economics . Despite Nick's kind invitation, I'm afraid I have no.....
» 1/02/2013 11:00:17 AM . Dear Squeers, . Conscience has to do with awareness of what is at stake from a moral .....
» 1/02/2013 9:57:13 AM . Dear Squeers, . Many thanks for your explanations and clarifications. Though I see n.....
» 31/01/2013 2:41:34 AM . Dear Squeers, . You certainly covered a lot of ground in your last post. I am not as .....
» 29/01/2013 9:22:56 PM . Dear David G., Poirot & Squeers, . David G - I am pleased you are happy to stay with.....
» 26/01/2013 10:03:50 PM . Dear David G. . Don't let it get you down, old mate. Here's something to cheer you up.....
» 26/01/2013 1:28:47 AM . Dear Poirot & Squeers, . Thank you for your kind words. It is comforting to learn tha.....
» 25/01/2013 1:59:07 AM . I strongly recommend reading, or re-reading, Glen Coulton's article published on OLO on.....
» 25/01/2013 1:37:17 AM . Dear David, Poirot, Shadow & Squeers, . I see you have been talking about me during m.....
» 22/01/2013 11:47:56 PM . Economies should be shaped to suit man - Comments ... . "CAP" ON INCOMES - .....
» 22/01/2013 8:39:52 AM . Dear Squeers, . You wrote to Wm Trevor: " I've been researching materialism and .....
» 21/01/2013 2:27:54 AM . Dear David G. and Nick Rose, . David - Tony Lavis indicated some figures on Russia .....
» 20/01/2013 10:21:47 AM . Dear David G., Shadow Minister and Tony Lavis, . Apparently I inadvertently opened th.....
» 19/01/2013 4:01:12 AM . Dear Belly . Sorry I could not get back to you earlier. I'm afraid I am not very opt.....
» 18/01/2013 11:54:18 PM . Dear David G. . You indicate in your previous post: "The Americans are the worl.....
» 18/01/2013 9:08:52 AM . Margaret Thatcher: “ ... we all agreed that if you try to take the fruits of Christiani.....
» 17/01/2013 2:22:04 AM . Dear Mr Opinion . Here is the link to the precise "terms of reference" of t.....
» 17/01/2013 1:27:50 AM . Dear Mr Opinion . In announcing its creation, Julia Gillard indicated that the Royal .....
» 12/01/2013 3:35:36 AM . Dame Helen Mirren: " I would describe myself as a Christian who doesn't believe in.....
» 12/01/2013 2:03:06 AM . Dear Helen, . Alain de Botton seems to have a few good, what I should call "comm.....
» 30/11/2012 3:06:42 AM . Dear Sheleyah, . According to the Australian Government web site: "Under the C.....
» 28/11/2012 9:26:37 PM . Understood, George ... . though that was a bit naughty of you ... Here is something .....
» 28/11/2012 12:30:14 AM . Dear George, . I am sure you are right in thinking we still have a lot to learn about.....
» 27/11/2012 1:47:52 AM . Dear George, . "I am familiar with the conclusion atheists draw from the more or.....
» 26/11/2012 8:08:45 AM . Dear George, . Carl Sagan's problematic of God or no God leads to a dead end. By an.....
» 24/11/2012 11:10:13 PM . Dear George, . Thank you for those indications on Buddhism. I make a distinction bet.....
» 24/11/2012 7:40:30 AM . Dear George, . Yes, it's good to have cleared the air on that one, George. Now we kno.....
» 23/11/2012 2:59:04 AM . Dear George, . Cohn-Bendit was one of the leaders of the student riots in France in M.....
» 22/11/2012 7:59:08 PM . Dear George, . Sex crimes are rampant in society. Rape is the number one of all major.....
» 22/11/2012 12:19:02 AM . Dear George, . It is nice to see you understand and that it is not just with your int.....
» 21/11/2012 2:46:42 AM . Dear George, . It took me almost 60 years to discover and understand how religion and be.....
» 20/11/2012 1:02:28 AM . Dear George, . It's always a pleasure exchanging with you. We seem to be so different.....
» 19/11/2012 8:43:24 AM . Dear George, . I think you've summed it up quite well. The thing that bothers me mos.....
» 18/11/2012 12:37:28 AM . Oops! I posted that on the wrong thread. . I have now posted it where it should have.....
» 18/11/2012 12:22:37 AM . Dear George, . Thank you for your explanations and clarifications. Please allow me, .....
» 18/11/2012 12:20:08 AM . Dear George, . Thank you for your explanations and clarifications. Please allow me, .....
» 17/11/2012 4:43:53 AM . Dear George, . "The preceding two posts are a good example. If you really think .....
» 17/11/2012 4:05:33 AM . Dear Yuyutsu, . "You got me wrong: the spirit and the body are not the same. Spi.....
» 17/11/2012 3:43:07 AM . Dear Candide, Dear Suseonline, . Unlike cannibalism, I have never heard of paedophili.....
» 17/11/2012 2:45:14 AM . Dear George, Dear McReal, . "The 21st century is going to be the last century fo.....
» 17/11/2012 2:01:19 AM . Onward, Christian soldiers, marching as to war, With the cross of Jesus going on before.....
» 16/11/2012 8:01:31 PM . Dear George, . “Preconceived hatreds and emotions are not a good guide to … actually .....
» 16/11/2012 1:19:50 AM . Alkali metals + water = Explosion! . There is ample evidence to prove that catholic p.....
» 16/11/2012 1:08:59 AM . Alkali metals + water = Explosion! . There is ample evidence to prove that catholic p.....
» 15/11/2012 9:46:01 PM . Dear Yuyutsu, . "Isn't tearing up the body, or parts thereof, away from the soul.....
» 15/11/2012 10:33:13 AM . Dear Yuyutsu, . If the problem were primarily of a spiritual nature, it would seem ap.....
» 10/10/2012 2:27:47 AM . Dear Squeers, . Sorry I couldn't get back earlier to you, cobber, I went on walkabout.....
» 8/10/2012 9:11:51 PM . Dear Squeers, . Thanks for letting me off the hook. It would have been quite a challe.....
» 7/10/2012 10:11:16 PM . Dear Squeers, . I'm afraid I do not merit your compliments. Any romanticism you perce.....
» 7/10/2012 10:08:24 PM . Dear Poirot, . Thank you for introducing me to José Ortega y Gasset. I looked him up .....
» 6/10/2012 11:16:28 PM . Dear Squeers, . Thank you for filling in the details. I tend to have a telescopic vis.....
» 6/10/2012 11:01:48 PM . Dear Poirot, . Thank you for expanding on your previous post. I can equate to what yo.....
» 6/10/2012 6:07:05 AM . Dear Poirot, Dear Squeers, . It seems to me that you raise the question of individual.....
» 4/10/2012 11:16:20 AM . Dear Dan, . Thank you for explaining your comments and placing them in context. We .....
» 4/10/2012 9:53:03 AM . Dear Poirot, . You certainly have some powerful thought waves. From Australia to Fran.....
» 4/10/2012 9:48:29 AM . Dear WmTrevor, . "If you go with the concept of solipsism then everything experi.....
» 3/10/2012 9:46:58 AM . Dear Poirot, . " On the testimony of those original thinkers....not only verbal .....
» 3/10/2012 6:13:54 AM . Dear Squeers, . My previous post to WmTrevor was an attempt to highlight HIS definiti.....
» 2/10/2012 10:21:51 AM . Dear WmTrevor, . I think I see what you mean about original ideas. I find it impossi.....
» 2/10/2012 2:31:26 AM . Dear Dan, . It is my understanding that for any theory to be accepted, if only tempor.....
» 2/10/2012 2:22:46 AM . Dear cohenite, . Many thanks for that interesting comparative study of evolutionary t.....
» 1/10/2012 9:00:04 AM . Dear Poirot, . You may be right. Perhaps we are inverting our "priorities" .....
» 30/09/2012 2:00:20 AM . Dear Dan, . Each generation is brought into the fold of religion as quickly as possib.....
» 29/09/2012 2:02:03 AM . Dear Moira, . Thank you for drawing my attention de Mr Hilaly and his opinion of Aust.....
» 27/09/2012 2:03:59 AM . Dear mykah, . Don't look now but your list of definitions of marriage is incomplete. .....
» 27/09/2012 12:18:19 AM . Dear Poirot, . Many thanks for that link to the web site of the late Joe Bageant. He .....
» 27/09/2012 12:14:59 AM . Dear Dan, if I may, . Thank you for your concern. I shall keep an eye open and, as an.....
» 26/09/2012 6:35:50 AM . Dear david f., Thank you for that very interesting social map of the US. I shall keep .....
» 26/09/2012 6:25:14 AM . Dear Brian, Pericles , and Squeers, . "According to Pascal, Christian faith answ.....
» 24/09/2012 9:03:38 PM . Dear Dan S de Merengue, . I'm afraid I have no means of knowing what the motivations .....
» 24/09/2012 2:44:33 AM . Religious belief, or faith, is a double edged sword. On one edge, it is a source of h.....
» 23/09/2012 1:36:12 AM . Dear Tony Lavis, I neglected to thank you for that interesting link to the web article.....
» 21/09/2012 10:44:28 PM . Dear Bernard, if I may, . France is due to become the 12th country in the world to pa.....
» 21/09/2012 9:49:52 PM . Dear diver dan, . I rarely take the time these days to sit on fences. I did it occasi.....
» 21/09/2012 1:41:15 AM . Dear david f., . Thank you for reading my thoughts and generously using some of your .....
» 20/09/2012 1:49:44 AM . Dear diver dan, . "It is no secret that atheists and the homosexual lobby, are j.....
» 19/09/2012 1:38:10 AM . Dear Brian, . Just a brief comment on the title of your article "Reason has its .....
» 18/09/2012 10:48:13 PM . Dear Brian, if I may, That is a thoughtful and analytical article. I agree with much o.....
» 4/04/2012 11:08:32 PM . "If God did not exist it might be necessary to invent him, or her" ! . That.....
» 26/03/2012 9:48:21 PM . ARE THERE RELIGIOUS TEACHERS IN SCHOOLS ? . I am afraid I have been away from home to.....
» 5/11/2011 10:02:07 AM . Dear Hasbeen, . I understand your distrust with certain forms of "vision". .....
» 5/11/2011 1:10:54 AM . Dear Diver Dan, . "Take our great Winston Churchill. Now there was a leader with.....
» 5/11/2011 12:27:21 AM . Dear Hasbeen, . "I still don't like your idea for choosing leaders. The general .....
» 4/11/2011 3:01:54 AM . Dear Hasbeen, . I'm afraid I've never had the pleasure of working in a 10,000 acre pa.....
» 4/11/2011 1:52:46 AM . Dear Diver Dan, . There are indeed some dangerous monsters lurking in the basement of.....
» 9/09/2011 3:16:36 AM . Dear Squeers, . I grant you it is indeed a somewhat reminiscent and nostalgic tale of.....
» 5/09/2011 10:04:37 PM . Dear Otokonoko, . Understood and agreed. There are two things that bother me. Most im.....
» 4/09/2011 9:30:41 AM . Dear Otokonoko, . I believe the essence of the message here is not that which you con.....
» 2/09/2011 10:13:20 PM . Dear Pericles, . You could be right in thinking that "The DA system is not desig.....
» 2/09/2011 8:45:03 PM . Oops ! . That's an amusing typing error. In the last paragraph, I meant to type ".....
» 2/09/2011 8:38:23 PM . Dear Briar Rose . "And am intrigued by your final paragraph. Does this mean weal.....
» 2/09/2011 2:34:54 AM . EPHEMERAL JUSTICE FOR AN EPHEMERAL ENCOUNTER … . One was an elderly white male Jew. T.....
» 12/08/2011 2:05:27 AM . Dear Joe Loadmouth, . After Jesus and Marx ... here comes the Spring ! For each epoch.....
» 11/08/2011 11:32:18 AM . NAPOLEON, STALIN, MAO, CASTRO ... . Were they revolutionaries ? Perhaps. Were they di.....
» 3/07/2011 8:02:53 AM . Dear Rien Huizer, . I agree it's by no means a simple matter to sort out. If it were .....
» 1/07/2011 8:05:10 AM . Dear stevenlmeyer, . I couldn't agree with you more about the Americans and the Chine.....
» 1/07/2011 7:23:53 AM . Dear Rien Huizer, . You wrote: " ... flaoting currencies do not devalue, they ad.....
» 30/06/2011 12:26:23 AM . Dear stevenlmeyer, . You are right. It's not an easy equation to solve. A devaluation.....
» 29/06/2011 8:59:15 PM . Dear stevenlmeyer, . So called "pure free floating currencies" exist in the.....
» 15/06/2011 2:13:45 AM . Dear Squeers, . I would gladly offer you a cup of coffee if you manage to come to Par.....
» 13/06/2011 11:40:06 PM . Dear Squeers, . Given the extraordinary feat nature (random variability of matter and.....
» 13/06/2011 8:48:56 AM . Dear Poirot, . Thank you for those observations of Noam Chomsky on Ernst Mayr's resea.....
» 12/06/2011 11:11:37 PM . Dear Squeers, . Thank you for the link to Fredric Jameson's paper on Post-modernism. .....
» 12/06/2011 10:53:26 AM . Dear Poirot, . Thank you for the insight to some of Koestler's ideas. I am afraid I a.....
» 11/06/2011 11:17:44 PM . Dear Poirot, . That does sound interesting. I'll see if I can find Arthur Koestler's .....
» 10/06/2011 11:20:24 PM . Dear Poirot, Dear Squeers, . Whenever I approach this subject (of the emergence of th.....
» 10/06/2011 1:17:18 AM . Dear Squeers, . "Democracy yes, but the current state of democracy leaves much t.....
» 9/06/2011 7:46:14 AM . Dear Squeers, . "Something's rotten in the Western States, and will continue to .....
» 9/06/2011 6:48:09 AM . Dear Arjay, . Thank you for the link to the Max Keiser blog. He seems quite intellige.....
» 8/06/2011 2:33:10 AM . Dear suzeonline, . In accordance with American criminal procedure, following DSK's &q.....
» 8/06/2011 1:49:44 AM . Dear Arjay, . That's surprisingly strong language for somebody whose intelligence, mo.....
» 7/06/2011 11:34:37 PM . Dear Squeers, . You pose some very interesting questions. I am sure William Shakespea.....
» 11/05/2011 5:20:34 AM . Effect of 2 quakes on New Zealand economy ... . The International Monetary Fund (IMF).....
» 10/05/2011 12:27:29 AM . Dear Peter, . Perhaps I should also comment on your idea that: "Voluntary transa.....
» 9/05/2011 9:17:40 PM . Dear Peter, . I have no particular point to make. I simply thought you might be inter.....
» 9/05/2011 3:27:31 AM . Oops ! The Gini coefficients indicated for Russia are for the same period from 2000 t.....
» 9/05/2011 1:18:26 AM . Dear Peter, . Just a few comments on your point: "... democracy, which is highly.....
» 8/05/2011 1:39:46 AM . Dear Peter, . Before commenting on your article "Ecological sustainability and e.....
» 6/05/2011 8:58:00 PM . Dear Squeers, Houellebecq, Poirot et al . Perhaps you may be interested in reading th.....
» 10/02/2011 6:24:01 AM . People cry wolf ! . No further comment. ......
» 29/10/2010 12:30:56 AM . Dear ALGOREisRICH, Yabby, . As anybody who has had to do business in a number of diff.....
» 15/10/2010 12:27:14 AM . Dear Max, . Well done, I couldn't agree more. Perhaps this article may be of interest.....
» 13/10/2010 7:39:07 AM . Dear George, . "...I am not sure to what extent I succeeded in answering your tw.....
» 10/10/2010 9:33:01 PM . Dear George, . "Perhaps one should distinguish between (negative) criticism as &.....
» 10/10/2010 5:04:18 AM . Dear George, (continued) . I had not heard of the 6 to 60 year poem you indicate. How.....
» 10/10/2010 1:26:35 AM . Dear George, . "One usually consults a dictionary with an a priori acceptance of.....
» 9/10/2010 12:35:18 AM . Dear George, . That's strange, your "continued" posts had not arrived when .....
» 9/10/2010 12:14:02 AM . Dear George, . Whilst waiting for your "continued" post, I should say I fin.....
» 7/10/2010 3:15:14 AM . Dear George, (continued) . One thing I realised when my children had finished their s.....
» 7/10/2010 2:56:58 AM . Dear George, . Thank you for those explanations. I had overlooked the fact that, as y.....
» 6/10/2010 3:31:40 AM . Dear George, . "Burdened with religion" is fine for "nábožensky zatíže.....
» 6/10/2010 2:19:28 AM . Dear Stephen, . You wrote: "Freud's concept of the superego, while useful for u.....
» 5/10/2010 3:31:08 AM . Dear Stephen, (continued) . At the end of my first post (above) I should have written.....
» 5/10/2010 3:25:03 AM . Dear Stephen, (continued) . Not surprisingly, my definition of "truth" is f.....
» 5/10/2010 2:51:50 AM . Dear Stephen, . Dreams were the stock in trade of Sigmund Freud. Your story appears a.....
» 4/10/2010 6:12:41 AM . Dear George, . It would have been difficult for you to flee any further on this earth.....
» 4/10/2010 2:32:15 AM . Dear Squeers and George, . I am afraid my French suddenly pops up sometimes in my Eng.....
» 3/10/2010 6:36:24 AM . Dear George, . It is amusing to learn that we nearly crossed paths a short lifetime a.....
» 1/10/2010 8:44:07 AM . Dear George, . Thank you for that detailed analysis. It seems there has been a misund.....
» 30/09/2010 3:51:39 AM . Dear george, . It seems I closed the book too soon. However, I understand your concer.....
» 29/09/2010 8:53:57 PM . Dear George, . "You are apparently referring to my sentence "seeing Catholi.....
» 29/09/2010 8:44:04 AM . Dear George, (continued) . I do not imagine for one minute that you are a fan of Dori.....
» 29/09/2010 8:10:05 AM . Dear George, . Thank you for those fleeting insights into your childhood and adolesce.....
» 28/09/2010 8:19:51 AM . Dear George, . I am pleased to hear that I did not shock you. Thank you for your reas.....
» 27/09/2010 5:48:46 PM . Dear George, (continued) . I am sorry for the delay in sending this. It got blocked b.....
» 27/09/2010 7:22:59 AM . Dear George, . "Do you really need to be given examples of "religious insig.....
» 26/09/2010 11:30:53 PM . Dear Squeers, . "Marx's notion that we are distorted by the competitive relation.....
» 26/09/2010 11:24:43 AM . Dear Squeers, . It was William Shakespeare’s signature I was expecting at the end of .....
» 26/09/2010 11:20:37 AM . Dear Poirot, . It is interesting to learn that architecture brings out the artist in .....
» 25/09/2010 11:51:42 PM . Dear Squeers, . Your reflections on "spirituality" appear close to the phil.....
» 25/09/2010 3:51:22 AM . Dear George (continued), . It is also possible that the church may "fear" t.....
» 24/09/2010 11:59:29 PM . Dear George, . You wrote: “how would you "preserve" religion to "cons.....
» 23/09/2010 10:17:10 AM . Dear George, . In my view, education is more important today for the well being of hu.....
» 23/09/2010 12:00:59 AM . Dear Squeers, . You wrote to George: "I do see belief as "mental starch&qu.....
» 22/09/2010 3:20:46 AM . Dear George, . You wrote: "If atheism is simply “lack of belief (in God)” how c.....
» 22/09/2010 2:33:09 AM . Dear Squeers, . You write: ["militant atheism" is just an inflammatory phr.....
» 20/09/2010 11:45:24 PM . Dear George, . You wrote: "You are right that Castro and Allende implemented, w.....
» 20/09/2010 6:56:45 AM . An irresponsible Pope ? . The Roman Catholic Church must surely be one of the largest.....
» 20/09/2010 2:55:34 AM . Dear George, . You wrote: “I agree that there are many things I could have mentione.....
» 17/09/2010 11:30:50 PM . Dear George, . You wrote: "Lenin did that but he could not convince the inhabit.....
» 17/09/2010 10:32:15 PM . Dear Runner, (continued) . Prior to legalization, as many as 5,000 American women die.....
» 17/09/2010 8:22:10 PM . Dear Runner, . You wrote: "and yet George Bush had the intelligence to understa.....
» 17/09/2010 8:27:27 AM . Dear Squeers, . You wrote: "Dear Banjo, you're as elusive as ever; not sure whe.....
» 16/09/2010 10:14:26 PM . Dear Poirot, . "... George W. Bush was an ignorant, unintelligent man who was en.....
» 16/09/2010 7:39:08 AM . Religion and the State . The Pharaohs of ancient Egypt considered that they were gods.....
» 14/09/2010 8:20:47 PM . Dear David F., . Yes I noticed you are more inclined to debate than dialectic, though.....
» 13/09/2010 12:15:30 AM . Dear Mac, . It seems there is no consenus among historians on the motivations of Urba.....
» 12/09/2010 12:47:47 AM . IN THE NAME OF GOD . The righteous punishment decreed by Peter Jones and Osama bin La.....
» 11/09/2010 7:32:37 PM . Dear David & Poirot, . The world would be a better place if all debate could become d.....
» 11/09/2010 8:22:16 AM . Dear Dr Muqtedar Khan, . The fratricidal family feud continues. It has been going on.....
» 10/09/2010 1:13:18 AM . Dear David F., . You raise a question of semantics. I understand "hierarchy".....
» 9/09/2010 7:15:33 AM . Dear David F., . You wrote to Poirot: "Heirarchical order is a human idea".....
» 8/09/2010 7:26:02 AM . Dear David F., . Gosh, you should take a day off more often. That was a very relaxed.....
» 7/09/2010 9:13:10 PM . AN AUSTRALIAN BURQA & NIQAB . The burqa and niqab appear to be an inexhaustible inspi.....
» 7/09/2010 2:07:55 AM . Dear Squeers, . Thank you very much for your very interesting and all too brief cours.....
» 7/09/2010 1:46:08 AM . Dear David F., . "Hegel saw freedom as humanity working together as an organic w.....
» 6/09/2010 2:03:30 AM . Dear David F., . "I have no reason to think that the Marxist societies would be .....
» 6/09/2010 1:46:26 AM . Dear Squeers, . I confirm my association by telepathy with David in his reply to your.....
» 5/09/2010 1:46:11 AM . Dear David and Squeers, . The financial crisis hurricane that swept through Europe on.....
» 4/09/2010 2:47:16 AM . Dear David F., . I have it from the horse's mouth that it was not George (dubya) Bush.....
» 4/09/2010 1:52:02 AM . Dear Squeers, . I am sure I have no lessons to give either you or David F. regarding .....
» 3/09/2010 10:11:23 PM . Dear David F., . "Marx suffered during his life. Some people can suffer and tran.....
» 3/09/2010 7:13:39 AM . Dear All-, David F. and Squeers, . Karl Marx is a closed book. He wrote the final cha.....
» 2/09/2010 7:01:31 AM . Dear David F., . Passing from theory to practice, whatever the domain, is a perilous .....
» 28/08/2010 11:36:59 PM . Contnued ... . What the Sahih al-Bukhari text does reveal, however, is that not only .....
» 28/08/2010 9:56:34 PM . Origin of Islamic Hijab: . Prior to the Hijab, women used to cover their heads with t.....
» 28/08/2010 4:32:08 AM . Dear ALGOREisRICH, . I wrote "thread" not "web". Four fibres inti.....
» 27/08/2010 7:35:53 AM . Dear federalist, . Thank you for your remarks. You indicate: "In a free co.....
» 25/08/2010 11:36:17 PM . Oops and oops again ... . I am sure you will all have corrected my spelling of ".....
» 25/08/2010 11:28:04 PM . Oops ... I meant to say ... . "The athorisation should apply to CONSENTING adult.....
» 25/08/2010 11:19:11 PM . A legal Australian burqa & niqab ! . Provided commonly accepted public codes of decen.....
» 24/08/2010 8:48:58 PM . Continued ... . Need I add that in a democracy such as Australia, any political allia.....
» 24/08/2010 8:38:35 PM . Well, it looks like ... . a majority of Australians does not want either Gillard or A.....
» 24/08/2010 5:15:50 AM . Continued ... . Need I add that in a democracy such as Australia, any political allia.....
» 23/08/2010 11:36:05 PM . Well, it looks like ... . a majority of Australians does not want either Gillard or A.....
» 20/08/2010 8:12:12 AM . Dear Ron in Bennelong, . Re: Your comment on page 10 of this thread: I am sorry I ha.....
» 18/08/2010 3:18:03 AM . Dear Ron in Bennelong, . Indeed, Australia is a "commonwealth" or, in other.....
» 17/08/2010 7:16:54 PM . Dear Ron in Bennelong, . It's nice to hear that "Gillard wants a Republic when t.....
» 17/08/2010 1:36:47 AM . My dear compatriots, . Please allow me to suggest that the day we feel sufficiently m.....
» 10/08/2010 9:21:33 PM . Dear Squeers, . The larvatus prodeo of Descartes suits me better than even the most f.....
» 10/08/2010 6:19:08 PM . Dear Squeers, . That is quite a remarkable text. If Freud could re-read it today, the.....
» 9/08/2010 9:05:27 PM . ooups ! . Obviously, I meant to write "... I do NOT consider it important ...&qu.....
» 9/08/2010 8:59:36 PM . Dear One under God, . I appreciatze your efforts on my behalf. I have carefully exam.....
» 8/08/2010 9:29:34 PM . Dear One under God, . I am both touched and honoured that you wish to share your spir.....
» 8/08/2010 7:15:14 AM . Dear AJ Philips, . Thank you for your comments and that interesting link. It certainl.....
» 7/08/2010 5:00:45 AM . Dear Oliver & David F., . Many thanks for your comments and information on the questi.....
» 5/08/2010 11:33:28 PM . Dear AJ Philips, . You wrote to George: " ...there is absolutely no evidence wh.....
» 2/08/2010 11:38:02 PM . Dear Squeers, Dear Oliver, . Thank you for your comments on the "Case for the ex.....
» 2/08/2010 7:46:22 PM . Dear David F, . Back on page 65 of this thread I noted that in your excellent text on.....
» 1/08/2010 7:04:28 PM . Dear David F, . In my previous post to you, I have just noticed I added a colon punct.....
» 1/08/2010 2:03:27 AM . Dear David F, . As you brilliantly explained to ALGOREisRICH on another thread, (http.....
» 1/08/2010 1:33:37 AM . Continued … . Pliny, a contemporary of Tacitus, was Governor of Bithynia in Asia Mino.....
» 1/08/2010 1:30:53 AM . Dear all, . A very good friend of mine presents the case for the existence of Jesus as.....
» 29/07/2010 12:01:12 AM . Dear Squeers, . Thank you for your reading suggestions. I'll look them up with intert.....
» 28/07/2010 7:30:06 AM . Continued ... Dear David, ... . Naturally, I agree with your point by point criticism.....
» 28/07/2010 7:25:44 AM . Dear David, . Your indictment of Karl Marx on the basis of the facts cited is perfect.....
» 8/07/2010 6:42:01 PM . Dear Ludwig, . In the event of amalgamation, a more prosperous New Zealand would be a.....
» 8/07/2010 8:24:31 AM . AN AUSTRALIAN & NEW ZEALAND REPUBLIC . I see more good reasons for this to happen tha.....
» 6/07/2010 7:40:26 PM . AN AUSTRALIAN & NEW ZEALAND REPUBLIC . Hi everyone ! Perhaps you may be interested i.....
» 4/07/2010 3:33:12 AM . Dear George, . " ... you have the right to thus dismiss any field of enquiry ........
» 2/07/2010 10:21:08 PM . Dear George, . " ... the interface between the philosophies of science and relig.....
» 2/07/2010 1:25:27 AM . Dear George, . ">>Belief in the supernatural is irrelevant to the project&.....
» 30/06/2010 9:06:24 AM . Dear George & Oliver, . Sustained intellectual developement certainly seems the right.....
» 29/06/2010 2:22:12 AM . Dear George & Oliver, . AJ's comments seem quite pertinent. Employing science as an .....
» 28/06/2010 9:02:53 AM . Dear George, . You wrote: "... I am not sure what could play the role of mathem.....
» 27/06/2010 1:34:39 AM . Dear George, . That's OK. I was just concerned you may not understand what I was tryi.....
» 26/06/2010 9:39:03 AM . OOPS ... ! . Yes, I meant a 500 page thesis ... ......
» 26/06/2010 9:31:36 AM . Dear George, . You are quite right. We have to adopt a common definition of what we a.....
» 25/06/2010 8:06:55 PM . ANOTHER BASH AT THE NAIL ! . Please excuse me for having another bash at the nail. As.....
» 25/06/2010 9:08:07 AM . ON THE NATURE OF SWEEPING STATEMENTS . In addition to the various sweeping statements.....
» 24/06/2010 8:34:39 AM . Dear George, . I googled as you suggested and obtained the following results: ".....
» 23/06/2010 9:58:59 AM . SCIENCE V RELIGION / THE NUMINOUS, THEORIA, VISIONS, MIRACLES ... . Competition betw.....
» 23/06/2010 9:51:30 AM . Dear George, . By "scientific proof" I mean whatever justifies the assertio.....
» 22/06/2010 2:42:51 AM . Dear George, . I understand you are wondering what religion is and what purpose it se.....
» 18/06/2010 8:43:24 AM . Dear David F . As regards the occasional outlandish statements of our camerade-in-wri.....
» 17/06/2010 1:37:02 AM . Dear Runner, . My question: "Who can honestly imagine that all the "pervers.....
» 16/06/2010 11:39:19 PM . Dear Runner, . Re: your post, page 10: "Adults have the right pretend that God .....
» 16/06/2010 8:16:39 AM . @ ALGOREisRICH NEITHER INFORMATION NOR INDICATION . It is not the role of publcs sc.....
» 15/06/2010 11:33:11 PM . SOME GO FOR THE BODIES & "SOULS" AS WELL . There are no "more noble&qu.....
» 12/06/2010 6:58:32 AM . OH YOU SAID REALITY ? . I guess that's what hits you when you cross a busy road witho.....
» 11/06/2010 9:49:40 AM . DID YOU SAY TRUTH ? . Off the cuff, I would say that truth is information that has no.....
» 6/06/2010 6:26:22 AM . Dear David F., . Thanks for the explanation. That's quite clear. ......
» 5/06/2010 9:12:10 PM . Dear Oliver, . "I suspect the case has more to the quality of the "locus&qu.....
» 5/06/2010 8:43:47 PM . Dear George, . "I am not sure what “principle“ you are referring to" I was.....
» 5/06/2010 5:37:08 AM . Dear George, . Thanks for taking a double dip at my question on observer dependence. .....
» 4/06/2010 10:54:18 PM . Dear George, . Thank you for the introduction to what appears to be interesting readi.....
» 3/06/2010 11:48:33 PM . Dear Oliver, Dear David F., . I am intrigued by your observations regarding the relat.....
» 3/06/2010 7:24:00 AM . Dear Suzeonline, . "No creationist can ever 'prove' that God created the world o.....
» 1/06/2010 11:34:42 PM . PERCEPTION, INTERPRETATION, COMMUNICATION . Science and religion appear to be the yin.....
» 1/06/2010 8:42:01 AM . Dear Oliver, . "Was the creation of Satan intelligent design? God in so doing ul.....
» 30/05/2010 10:59:13 PM . Dear Oliver, . "Can God create a better designer, more capable than himself? Or .....
» 30/05/2010 9:32:38 AM . THE WONDER OF EVE . It was long before Jesus appeared on the scene that the world gav.....
» 28/05/2010 11:21:19 PM . ABRAHAM'S APPLE TREE . So, according to Abraham, it was during a terrible fit of jeal.....
» 27/05/2010 9:59:04 PM . SCIENCE AND RELIGION . Somebody suggested, earlier on, that the tree of knowledge was.....
» 27/05/2010 5:16:56 AM . TOO MANY GODS SPOIL THE BROTH ! . Abraham detested looking after the shop in his fath.....
» 25/05/2010 11:03:52 PM . Dear Bugsy, . If, as I suggested in my recent post, the subject of discussion on this.....
» 25/05/2010 8:33:01 PM . I D A PLEONASM ? . Please excuse my ignorance but I must confess I am rather surprise.....
» 25/05/2010 8:19:28 AM . PUBLIC RELATIONS . Public relations defined as the interaction of an individual wit.....
» 23/05/2010 8:41:19 PM . Dear Oliver . I see you have just chalked up a century on Mary's forum. Quite a remar.....
» 23/05/2010 1:24:04 AM . Dear Oliver, . " ... the matter of ridding the Church of the cover-up cardinals .....
» 21/05/2010 10:22:28 AM . Dear Oliver, . I do not think there is much to expect or to hope for in the way of ch.....
» 20/05/2010 1:44:49 AM . Dear Oliver, . Thank you for warning me that Benedict is a world class politician in .....
» 19/05/2010 6:21:41 AM . Dear Oliver, . Thank you for that interesting comment. Also, as you suggest to the mu.....
» 17/05/2010 2:45:38 AM . Dear Oliver, As George bows out and Mary remains discretely silent, please allow me to.....
» 13/05/2010 1:36:28 AM . Dear Mary, This is just to let you know I checked in to see if you replied to my post .....
» 12/05/2010 9:09:58 AM . Dear Mary, Perhaps you will agree that the first priority of the church should be to e.....
» 16/08/2009 10:50:21 PM . FREE TO CHOOSE . Now that society has authorized Mr Rossiter to choose whether he pre.....
» 10/08/2009 10:42:22 PM . EUTHANASIA TER . It must be more that ten years ago now that Peter, the elder brother.....
» 9/08/2009 11:23:29 PM . EUTHANASIA BIS . A well-to -do farmer in the Calvados in Normandy took a liking to Di.....
» 8/08/2009 1:16:58 AM . EUTHANASIA . My brother and I grew up with a dog called Nippy. Somebody left the gate.....
» 7/08/2009 11:01:36 PM . A MIND IN A JAR . I must confess that I do not know the details of this case. However.....
» 30/07/2009 8:16:33 PM . A LITTLE CLOSER TO HOME . I am sorry to have to repeat myself but I have already post.....
» 30/07/2009 7:48:23 PM . THE MASKS HAVE FALLEN ! . The French president, Nicholas Sarkozy (alias Napoleon Bona.....
» 27/07/2009 10:40:54 PM . THE REVELATION OF HIDDEN IDENTITY . What does hidden identity reveal? That you have s.....
» 30/03/2009 11:01:07 PM ... HOW ABOUT DEPUTY SHERIFF OF THE USA ? ... The world-wide image of Australia's Prime.....
» 28/02/2009 8:52:34 AM ... @ SHOWDOWN MINISTER ... That is the tendency. Is it fatality ? Do we have no choice .....
» 25/02/2009 9:56:54 PM ... @ DEAR WHISTLER, ... Reading your post brought back fond memories of that well-known .....
» 24/02/2009 8:29:03 AM ... WHY OPPOSE ASSIMILATION AND SELF-DETERMINATION ? ... In determining oneself, why shou.....
» 18/02/2009 10:11:23 PM ... SLAVERY TODAY ... Despite the fact that slavery was abolished officially some 150 yea.....
» 14/02/2009 9:04:19 PM ... REDUCING INDIGENOUS DISADVANTAGE ... The Chief Minister of the Australian Capital Ter.....
» 14/02/2009 6:34:24 AM ... THE STOLEN GENERATION ... For 80 years, from 1788 to 1868, the British government dep.....
» 12/02/2009 8:28:16 AM ... NEITHER YES NOR NO BUT HOW ? ... ... (continued) ... Yet, to many of us, It seems so .....
» 12/02/2009 8:22:37 AM ... NEITHER YES NOR NO BUT HOW ? ... My understanding is that the Aborigines had been liv.....
» 8/02/2009 11:48:12 PM ... ADVANCE AUSTRALIA FAIR ! ... I am not sure what the gentleman of Scottish origin had i.....
» 8/02/2009 12:33:00 AM ... ONE ACTIVIST MAY HIDE ANOTHER ... “Knowing others is wisdom, knowing thySelf is enli.....
» 6/02/2009 8:50:24 AM @ COL ROUGE … "When all the objectives of government include the achievement of equa.....
» 5/02/2009 11:53:39 PM HI FOXY ! … It was nice meeting you. I enjoyed your company on this debate. We may not ha.....
» 5/02/2009 8:01:27 AM ON DEMOCRACY AND MINORITIES (CONTINUED) … In my previous post, instead of “a non-indigen.....
» 4/02/2009 9:54:38 PM ON DEMOCRACY AND MINORITIES ... I have read or heard it said (I can not remember which),.....
» 4/02/2009 7:31:09 AM @ OJNAB My dear mirrored namesake, I heartily sympathise with you. I often wonder what I.....
» 3/02/2009 6:46:36 AM JUST BECAUSE SOME MINORITY GROUPS DO NOT IDENTIFY WITH AUSTRALIA'S BRITISH HERITAGE DOES N.....
» 3/02/2009 5:03:37 AM “THE BOTTOM LINE IS THAT AUSTRALIA DAY MARKS THE DATE OF WHITE SETTLEMENT AND NOTHING BEFO.....
» 2/02/2009 2:46:56 AM ON CULTURE AND CIVILISATION (CONTINUED) I see the the aborigines as having suffered from .....
» 2/02/2009 2:44:15 AM ON CULTURE AND CIVILISATION It seems to me that the epitome of culture and civilisation i.....
» 31/01/2009 8:13:57 PM BANJO PATERSON FOREVER Our hosts at On Line Opinion have informed me it is not possible t.....
» 30/01/2009 5:40:22 AM BANJO PATERSON IS NOT BANJO ! Apparently it is not so easy to change one's pseudo or nick.....
» 30/01/2009 5:13:43 AM BANJO PATERSON IS NOT BANJO ! The proximity of the two pseudos is understandably creating.....
» 28/01/2009 9:40:26 AM AUSTRALIA DAY Please allow me to suggest that Australia Day should be the day Australia b.....
» 14/01/2009 6:30:19 AM Hi Legal Eagle ! Thank you for your comments on justice and religion. I guess it all goes.....
» 13/01/2009 9:05:55 AM Hi Grim! I sure hope you are right. Being "close to the ground" sounds like a c.....
» 12/01/2009 7:16:03 PM @ Grim & Peter the Believer I suspect it is a little too early for a majority of Australi.....
» 12/01/2009 6:32:57 AM @ Legal Eagle The French president recently announced that the "juge d'instruction&q.....
» 21/11/2008 5:24:15 AM I appreciate your factual updates on local government, Scott. They are always well documen.....
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# AutoCAD 2023 24.2 Crack Free
See also Comparison of CAD editors for architecture and design List of CAD editors References Further reading Category:Computer-aided design software Category:3D modeling software Category:Graphic software for Linux Category:2006 software Category:Software that uses Qt Category:MacOS text-based graphics software Category:Industrial computing Category:User interface techniques Category:Windows text-based GUI editorsDesign, synthesis, and evaluation of novel thiazolidine derivatives as antiepileptic agents. Some thiazolidine derivatives were prepared and evaluated for the anticonvulsant activity in mice. The evaluation was carried out according to the maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ), and intraperitoneal (i.p.) zolpidem-induced seizure models. Furthermore, the activity of these compounds was assessed in the spontaneous seizure test in mice, and the results indicate that these compounds possess anticonvulsant activity. In particular, the compound 7e, which contains a piperidine moiety and 2-piperidin-1-yl-ethyl side chain at the 2-position of the thiazolidine ring, exhibited more anticonvulsant activity in the MES and scPTZ tests than the reference drug carbamazepine. In addition, compound 7e exhibited more potent anticonvulsant activity in both MES and scPTZ tests than zolpidem. These results strongly suggest that the compound 7e may be a promising candidate for further development as an antiepileptic agent.Multicenter Evaluation of Routine Postoperative Surveillance with CT Angiography for Cervical Artery Dissection. To evaluate the efficacy and safety of routine postoperative surveillance with computed tomography (CT) angiography for acute cervical artery dissection (CAD). This was a multicenter, retrospective review of consecutive patients undergoing surveillance of acute CAD. This study included 151 patients with 143 acute, unilateral cervical artery dissections. CT angiography was performed every 3 months in the acute phase and yearly in the subacute and chronic phases. The 2-year cumulative rate of stroke after surveillance was 2.0% (3 of 151 patients), and the rate of hemorrhage with persistent symptoms was 0.7% (1 of 143 patients). CT ang ca3bfb1094
Select file with Autocad. Enter the serial number of your license key and activation data key. Click on [Generate]. Install Autodesk Autocad for 2D. Thank you! Q: Sending image through socket TCP C# I am sending an image from a C# program to a DLL written in C++. I am using FileStream file = new FileStream(“image.jpg”, FileMode.Open, FileAccess.Read); byte[] buffer = new byte[file.Length]; file.Read(buffer, 0, buffer.Length); Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); s.Connect(new IPEndPoint(IPAddress.Parse(“192.168.1.10”), 8000)); s.Send(buffer); But in the DLL I’m not able to get the image. I have verified that the socket is not closed properly. The buffer is size of 1500 bytes. A: FileStream requires an open stream, which you don’t have. You need to create a socket and open the stream yourself. You also don’t need to do the file read yourself, the socket object has the option Send() method to do it for you. Just supply a buffer to send. Q: Is the number of linearly independent vectors that you can get by picking vectors at random still the same as the number of linearly independent vectors that you can get by picking vectors at random from $\mathbb{R}^n$? Let $V$ be a vector space over $\mathbb{R}$ and let $S$ be a subspace of $V$. Let $k$ be the dimension of the subspace $S$. Let $A$ be a subset of $V$ of size $k$. Then a vector $v\in V$ is said to be independent with respect to $A$ if $$\forall \vec{a}_1,\vec{a}_2\in A,\qquad \vec{a}_1\cdot\vec{a}_2=0\implies v\cdot(\vec{a}_1+\vec{a}_2)=0.$$ Let $n$
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# ASCII triangle in J
I've been doing code golf puzzles to improve my J. I'd appreciate any feedback on my solution to this problem.
The task is to take an integer and produce an ascii triangle as follows:
5
|\
| \
| \
| \
| \
------
My solution:
(#&'| \' @ (1,1,~])"0 i.) , ('-'#~>:)
• I think your answer fails for n=0. It should produce no output, but yours produces '-' Your code golf submission has a clever version that miles put in the comments. *,&'-' '|',.'\'{."0~_1-i. and it passes for n=0
– bob
Jul 23 '17 at 8:38
*,&'-' '|',.'\'{."0~_1-i
*,&'-' '|',.' \'{~=@i.
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## Fundamentals of Physics Extended (10th Edition)
The first thing we do for problems with a ramp is to set our coordinate axes so that the x axis is parallel to the plane and the y axis is perpendicular to it. We then need to resolve Fg (Force of the weight of the block) into its x and y components in the new coordinate system. Using the angle given and similar triangles, we find that Fg,x = Fgsin($\theta$) and that Fg,y = Fgcos($\theta$). To find the Tension, we see that it is in what we now call the x direction and so we list out all the forces acting in the x direction. These are T up the ramp and Fg,x down the ramp. since the block is not moving, the net Force must be 0 meaning that T - Fg,x = 0. Therefore, T = Fg,x = (8.5kg)(9.8\$m/s^2)sin(30) = 41.7 N
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## Strong Interaction
Is there a general equation for the Strong Interaction?
Yes -- the Langrangian is the Yang-Mills Lagrangian with the gauge group SU(3). ie L= phibar(i*Dslash)phi - 1/4 * (F^i_uv)^2 -m*phibar*phi where phi is the fermion (quark) field, F^i_uv is the gluon field tensor(s), m is the fermion mass, and D is the covariant derivative for SU(3).
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# Gödel's solutions to Einstein's relativity equations and their consequences
Gödel gave certain solutions to Einstein's relativity equations that involved a rotating universe or something unusual like that; that predicted stable wormholes could exist and therefore time travel, if one could travel through a wormhole. He was a genius but obviously many scientists today don't think time travel could exist. But his solutions to Einstein's equations do supposedly work. So could this work by Gödel imply time travel might be possible?
Gödel's rotating universe solution does allow for time travel (closed timelike curves), but it has nothing to do with wormholes--in such a universe one could travel into one's own past just by taking a rocket on a long-term looping path through space, from any starting location. This page discussing Gödel's solution includes a spacetime diagram showing how future light cones at different points in space become tilted with distance relative to a given point that we label as the center (and presumably this depends on the choice of spacetime coordinate system too, since I know that in other spacetimes like that of a non-rotating black hole, different coordinate systems give different conclusions about whether light cones "tilt" at points closer to the black hole):
And this in turn implies it's possible to find a path which always remains inside the future light cone of each point along it (with a number of such light cones illustrated), so that it can represent the world line of a slower-than-light particle, but which allows the particle to travel along an overall loop that brings it back into its own past:
This website by a physicist who did his thesis on Godel's solution gives a basic introduction to what "rotating universe" means in this context, and although it doesn't really give any details on how time travel would work in such a universe, it does mention that "direct measurements" based on measurements of planetary orbits relative to background stars can only show that if our universe is rotating at all, the rotation rate must be less than 0.1 arc seconds per century, not enough to rule out the possibility we live in a Godel universe where the rotation must be around 0.01 arc seconds per century. However, he also mentions that other types of measurements indicate a much smaller upper bound on the rotation rate, although the calculation requires some cosmological assumptions:
The microwave background radiation gives another means of determining the vorticity. It is known to be highly isotropic (equal in all directions), whereas rotation most likely would give some distortion (blueshift in some directions, redshift in others). Calculations along these lines give 5-13 orders of magnitude lower limits on the vorticity. But they don't constitute any proof as they are based on certain cosmological models.
More on observational constraints on rotation here and here. Note however that in addition to Gödel's original solution, which was a stationary solution, there are models of rotating universes that are also expanding, and at least some of these models don't have closed timelike curves, so it's possible that even if observations did show a significant rotation rate this would be of no use to would-be time travelers. The paper Contributions of K. Gödel to Relativity and Cosmology by physicist George F. R. Ellis, available as a pdf link on this page, says in section 3 that after discovering his original stationary rotating universe solution, in 1950 Gödel presented examples of "more realistic universe models that both rotate and expand" and that "These are now called Bianchi universes", and quotes Gödel saying that "The precise necessary and sufficient condition for the non-existence of closed timelike lines (provided that the one-parameter manifold of the spaces $\rho = const$ is not closed) is that the metric in the spaces of constant density be spacelike", with Ellis commenting that "if the surfaces of homogeneity are timelike then closed timelike lines will occur (because these surfaces are compact)" (I'd be interested to know what timelike surfaces of homogeneity would actually look like observationally, and whether there's any way they could be consistent with observations in our universe...a further subtlety is that apparently there can be Bianchi models where 'surfaces of homogeneity change from spacelike to timelike', as noted on p. 144 of The Future of Theoretical Physics and Cosmology, and p. 481 of Relativistic Cosmology, but I couldn't find any information on whether this type of solution contains closed timelike curves). This pdf of a physics thesis also discusses models with vorticity (rotation) and expansion, and says on p. 33:
Note however that a non-vanishing vorticity does not necessarily imply the existence of closed timelike curves. Is there then any further features concerning the vorticity associated with a realistic cosmological model? Based on observations, a realistic model of the universe requires that the vorticity and other perturbations are small compared to the expansion, essentially meaning that it is reasonably close to the Big Bang model. However, it is a shortcoming that very few exact solutions belonging to this category are known. There is actually only one known exact homogeneous perfect fluid solution with both vorticity and expansion, which was found by Rosquist and belongs to Bianchi type $VI_0$.
On the other hand, a traversable wormhole is a totally separate type of spacetime which is permitted by Einstein's theory of general relativity, and which doesn't require any large-scale cosmological assumptions like Gödel's spacetime or the Bianchi models. It would also permit closed timelike curves (time travel) under certain circumstances, as first elaborated in this 1988 paper. However, there is also speculation that quantum effects might prevent this (general relativity doesn't deal with the effects of quantum physics on spacetime curvature), see Stephen Hawking's chronology protection conjecture (and as I mentioned in a comment, some theoretical investigations of the chronology protection conjecture in string theory suggest quantum effects could also rule out time travel in a Gödel universe, see here for example). If you're interested in reading more about this stuff, the book Black Holes and Time Warps has a good introduction to traversable wormholes (and the main concepts of general relativity) by one of the physicists who discovered them as a theoretical possibility, and the more recent book Time Travel and Warp Drives has discussion of traversable wormholes along with a number of other spacetimes which would theoretically allow for closed timelike curves, along with discussion of how quantum effects might prevent them.
• Is Hawking's chronology protection conjecture more of an ad hoc conjecture or are there appropriate math theories to back it up? – 201044 Mar 19 '15 at 3:10
• @201044 - There is tentative support for it in calculations in semiclassical gravity (an approximate way of integrating quantum field theory into general relativity), and also in string theory, but without a complete theory of quantum gravity it's not possible to really confirm it even at a theoretical level. There are some more details and references in the chronology protection wiki article, and the book "Time Travel and Warp Drives" has a good discussion of it. – Hypnosifl Mar 19 '15 at 4:06
• These arguments are fascinating but speaking to an amateur physics enthusiast who is not that great at advanced physics arguments , like myself ; is there an answer to whether Godel's solutions to Einstein's equations implies Time travel is possible, that is understandable to a 'layman physics enthusiast'? – 201044 Oct 22 '15 at 4:19
I'm unsure if you're specifically asking about the Gödel spacetime or if your question is a more general one of whether time travel can exist. So let me try to give a general answer that addresses both.
Einstein's equation tells us how the geometry of spacetime is related to the distribution of matter and energy. Leaving aside the vexed issue of quantum gravity, I think most of us believe what general relativity tells us i.e. if we take some distribution of matter and energy then GR will predict the correct geometry. So if we had a rotating universe then the spacetime would indeed be described by Gödel's metric and closed timelike curves would exist (though actually the Gödel universe is a rather impractical way of attempting time travel).
There are plenty of other perfectly good solutions to Einstein's equation that would allow closed timelike curves. However they all have something in common. In his paper on the Chronology Protection Conjecture Hawking proved that closed timelike curves cannot be created in a finite system without using exotic matter. The Gödel universe gets round this because it's infinite, while other cunning ideas like the Alcubierre drive require exotic matter.
Now, as far as we know the universe isn't rotating, and exotic matter doesn't exist. So (I guess) most physicists don't believe that time travel is possible, even though Einstein's equation does have solutions that could allow it.
It's not unusual that well accepted theories can give bizarre results if you feed in bizarre initial conditions. For example Newton's equations of motion are (below relativistic speeds) amongst the most thoroughly tested and well accepted theories in physics. But if you feed in a negative mass then Newton's laws of motion predict some very strange behaviour. We don't regard this as a problem because no-one believes that negative masses exist. The situation is similar for closed timelike curves. Although general relativity does predict them it requires initial conditions that no-one thinks are possible.
• "Now, as far as we know the universe isn't rotating, and exotic matter doesn't exist." -- Certain types probably do--it's thought that the vacuum between parallel plates in the Casimir effect has negative energy, for example, though the Raychaudhuri's theorem and exotic matter section of the wiki on wormholes says it's unclear whether such effects could violate the averaged null energy condition in curved spacetime, but semiclassical calculations suggest they may. – Hypnosifl Mar 16 '15 at 13:04
• This point might border on pedantic, but when you say "The situation is similar for closed time like curves. Although [GR} does predict them... no-one thinks are possible." I would argue that Godel's spacetime is not disallowed by any laws of physics we're aware of, it's just that our universe doesn't appear to be rotating. This is a different situation that particles with negative or imaginary mass, which I would be more willing to definitely call impossible. It's certainly easy to imagine another universe that does rotate, and it's possible, this just doesn't happen to be one of them – Sean Mar 16 '15 at 13:22
• @Sean: hmm, well, possibly. The thing is that the Gödel universe is not just what you get if you take our universe and spin it on some axis. The Gödel universe is homogeneous in the sense that wherever you are in the universe you will observe it to be rotating about your position. There is no special point in the universe that is the axis of rotation. Whether this is actually physically possible is not at all clear to me. – John Rennie Mar 16 '15 at 13:32
• @Sean - As I mentioned above "particles" with negative mass might not be necessary, just a Casimir vacuum, and the 1988 paper on time travel with wormholes by Morris, Thorne and Yurtsever specifically imagines using the Casimir effect on p. 2. Also, there are versions of chronology protection which incorporate the holographic principle from string theory, and this might even rule out time travel in a Godel universe. – Hypnosifl Mar 16 '15 at 13:32
• But if it's an eternal (stationary) solution nothing "produces" it, just like nothing "produces" an eternal Schwazschild white hole/black hole, or an eternal static universe. And what do you mean it's not "local"? Isn't any GR dust solution local in the sense that each particle's movement is assumed to be determined wholly by the local curvature of spacetime at each point it passes through? And in GR that curvature is determined locally by the dust in the past light cone of each point. – Hypnosifl Mar 17 '15 at 14:27
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## Circumventing ThinkPad’s WiFi Card Whitelisting
What started as a simple Mini PCI Express WiFi card swap on a ThinkPad T61 notebook, turned into deploying a custom BIOS in order to get the card to work.
I love ThinkPad notebooks, they are workhorses that keep on going and going. I always keep my older models around for testing, and one of my old T61’s had an Intel 4965AGN card, that worked fine with Windows 10, until the release of the Anniversary / Redstone 1 update. After the RS1 update, WiFi would either fail to connect, or randomly drop out. The 4965AGN card is not supported by Intel on Win10, and the internet is full of problem reports of Win10 and 4965AGN cards.
Ok, no problem, I’ll just get a cheap, reasonably new, with support for Win10, Mini PCIe WiFi card, and swap the card. I got an Intel 3160 dual band 802.11AC card and mounting bracket for about $20. The 3160 is a circa 2013 card with Win10 support. I installed the card, booted, and got a BIOS error 1802: Unauthorized network card is plugged in. This lead me to the discovery of ThinkPad hardware whitelisting, where the BIOS only allows specific cards to be used, which lead me to Middleton’s BIOS, a custom T61 BIOS, that removes the hardware whitelisting, and enables SATA-2 support. I found working download links to the v2.29-1.08 Middleton BIOS here. The BIOS update is packaged as a Win7 x86 executable or DOS bootable ISO image. As I’m running Win10 x64, and I could not find any CD-R discs around, I used Rufus to create a bootable DOS USB key, and I extracted the ISO contents using 7-Zip to a directory on the USB key. The ISO is created using a bootable 1.44MB DOS floppy image, and AUTOEXEC.BAT launches “FLASH2.EXE /U”, I created a batch file that does the same. I removed the WiFi card, booted from USB, ran the flash, and got an error 1, complaining that flashing over the LAN is disabled. Ok, I enabled flashing the BIOS over the LAN in the BIOS, and rebooted. I ran the update again, and this time I got error 99, complaining that BitLocker is enabled, and to temporarily disable BitLocker. I did not have BitLocker enabled, so I removed the hard drive and tried again, same error. Must be something in the BIOS, I disabled the security chip in the BIOS, tried again, and the update starts, but a minute or so later the screen goes crazy with INVALID OPCODE messages. Hmm, maybe the updater does not like the FreeDOS boot image used by Rufus. Ok, let me create a MS-DOS USB key, uhh, on Win10, that turned out to be near impossible. Win10 does not include MS-DOS files, Rufus does not support custom locations for MS-DOS files, nor does it support getting them from floppy or CD images (readily available for download), the HP USB Disk utility complains my USB drive is locked, and writing raw images to USB result in a FAT12 disk structure that is too small to use. I say near impossible because I gave up, and instead went looking for an existing MS-DOS USB key I had made a long time ago. I am sure with a bit more persistence I could have found a way to create MS-DOS bootable USB keys on Win10, but that is an exercise of another day. Trying again with a MS-DOS USB key, and voilà, BIOS flashed, and WiFi working. I am annoyed that I had to go to this much trouble to get the new WiFi card working, but the best part of the exercise turns out to be the SATA-2 speed increase. This machine had a SSD drive, that I always found to be slow, but with the SATA-2 speed bump in Middleton’s BIOS, the machine is noticeably snappier. A couple hours later, my curiosity got the better of me, and I made my own version of Rufus that will allow formatting of MS-DOS USB drives on Win10. In the process I engaged in an interesting discussion with the author of Rufus. I say interesting, but it was rather frustrating, Microsoft removed the MS-DOS files from Win10, and Rufus refuses to add support for sourcing of MS-DOS files from a user specified location, citing legal reasons, and my reluctance to first report the issue to FreeDOS. Anyway, can code, have compiler, if have time, will solve problem. ## Self Signed BitFury Drivers Almost two years ago I pre-ordered some bitcoin mining hardware from Butterfly Labs, what a waste. After countless delays, more than a year late, they finally shipped the hardware, and given the low probability of ever recovering the money through mining, I immediately sold the hardware on eBay, for a little profit. In the mean time USB stick miners became available, outperforming GPU mining, and easy to setup and run. I’ve had a couple of ASICMiner Block Erupter’s running under my desk for some time, in the early days I saw some fractions of coins coming in, but in recent months they are so under-powered against the current hash-rates that they do little more than blink lights. There is a resurgence in USB stick mining hardware, specifically the Bitfury type devices, many based on the NanoFury open source project that provided software, design, and PCB schematics. I got myself a Red Fury, an Nano Fury II, and a Hex Fury. Compared to the 300MH/s of my little Block Erupters, these run at 2GH/s, 4GH/s, and 11GH/s respectively. There is still no way to ever make a profit in mining (at this scale), but I was really interested in seeing how these newer generation devices worked, especially since the publication of the NanoFury open source project, where in theory I could build my own. So what does this have to do with self signed drivers, well, my mining tool of choice is CGMiner, but CGMiner currently only runs Nano Fury II’s at half speed, requiring the use of BFGMiner to go full speed. But unlike CGMiner that accesses all USB devices via Zadig installed WinUSB drivers, BFGMiner requires native Windows drivers, and neither the Red Fury nor the Hex Fury drivers are signed, so no installation on Windows 8 x64 (without disabling driver signing on every boot). Looking at the INF files, all these devices do is register the USB hardware id as a generic null modem USB to COM bridge device, so no binaries required, just a signed CAT file. After a bit of searching I found that I was not alone in my frustration, and I found a self-signed Red Fury driver. But, the Hex Fury used a different hardware id, and most people used CGMiner, so no need for a signed native driver as Zadig took care of that for us. So, I created my own signing script and signed my own drivers, install ok, BFGMiner happy. If you just want signed drivers, get a copy of self-signed “Bitfury BF1” and “bi•fury” drivers here. If you are interested in signing your own drivers, read on. I tested on Windows 8.1 Update 1 x64: Install the Windows 8.1 SDK and WDK. Get the original “Bitfury BF1” and “bi•fury” INF files. The bf1.inf file is saved in *NIX format (CR), convert it to Windows format (CRLF). Create a self signed certificate: makecert.exe -r -pe -ss PrivateCertStore -sr localMachine -n "CN=BitFury Test Signing Certificate" "C:\BitFury\BitFuryTest.cer" Prepare the INF files, and create CAT files: stampinf.exe -n -f "C:\BitFury\bf1.inf" -d * -v * -c "bf1.cat" stampinf.exe -n -f "C:\BitFury\bifury_c4C.inf" -d * -v * -c "bifury_c4C.cat" inf2cat.exe /v /driver:C:\BitFury\ /os:7_x86,7_x64,8_x86,8_x64 Sign the CAT files: signtool.exe sign /v /s PrivateCertStore /n "BitFury Test Signing Certificate" /t http://timestamp.verisign.com/scripts/timestamp.dll "C:\BitFury\bf1.cat" signtool.exe sign /v /s PrivateCertStore /n "BitFury Test Signing Certificate" /t http://timestamp.verisign.com/scripts/timestamp.dll "C:\BitFury\bifury_c4C.cat" To use the drivers, you have to import the signing certificate into the local certificate store. As this is basically a self-signed CAT file, there are no trusted root certificates in the system that signed the signing certificate, and we need to add the signing certificate to the root and the trusted certificate stores. certmgr.exe -add -c "C:\BitFury\BitFuryTest.cer" -s -r localMachine root certmgr.exe -add -c "C:\BitFury\BitFuryTest.cer" -s -r localMachine trustedpublisher Alternatively you can run “certlm.msc”, and import the certificate file into the “Trusted Root Certification Authorities” and the “Trusted Publishers” hives. Last thing left to do is to use your newly signed drivers when selecting the custom driver from device manager. Here is a package with signed drivers, and scripts to help you sign your own INF files, and import the certificate. It should work on Windows 7 and Windows 8 x86 and x64. Your mileage may vary, use at your own risk 🙂 ## Windows 8 VIDEO_TDR_FAILURE Madness I finally figured out why I kept on getting VIDEO_TDR_FAILURE BSOD’s when installing Windows 8 on my SuperMicro workstations. It turns out that the problem goes away when I use a PCIe slot associated with CPU #1, instead of a slot associated with CPU #2. Some history on my adventures with Windows 8 and SuperMicro SuperWorkstations: I got ACPI_BIOS_ERROR BSOD’s while installing Windows 8, SuperMicro provided a Beta BIOS that resolved the problem. The Windows 8 install hangs if installing to a SSD drive on a LSI 2308 SAS controller, that issue is still unresolved, but can be worked around by connecting the SSD to the Intel SATA controller. I got VIDEO_TDR_ERROR BSOD’s while installing Windows 8 with a NVidia Quadro 5000 graphic card, same with an ATI FirePro V7900 or a NVidia GeForce GTX 680 or an ATI HD 7970. And this post is about resolving that problem. SuperMicro released v1.0a BIOS updates for the X9DAi and X9DA7 motherboards used in the 7470A-T and 7470A-73 SuperWorkstations. I was hoping this will resolve the VIDEO_TDR_FAILURE BSOD’s, but no. The X9DA7 BIOS updated without issue, but the X9DAi update reported an error at the end of the update process; “Error when sending Enable Message to ME”. I contacted SuperMicro support, and they asked me to make sure that there is no jumper on JPME1. There is no mention of JPME1 in the motherboard manual, but it is located next to JIPMB1, next to PCIe slot #1. The header had a jumper on pins 2 and 3, where the same header on the X9DA7 motherboard had a jumper between 1 and 2. I removed the jumper, and the BIOS update succeeded. Unlike the ACPI_BIOS_ERROR BSOD that happens during the WinPE phase of the install, the VIDEO_TDR_FAILURE BSOD happens on the first boot after the install, during the hardware detection and driver install phase. This means that the technique I used to kernel debug the initial boot phase will not work, as the second boot is using the BCD already deployed to the target hard drive. I had to modify the BCD of the already installed image, prior to the install continuing after the reboot. I tested many permutations of graphic cards and configurations, and it quickly became very annoying to have to type my Win8 product key every single time I boot and install. To avoid this I created configuration files in the sources directory on the install media, and this bypassed the key question. You can read more about the meaning of the file contents here: EI.cfg: [EditionID]Professional[Channel]Retail[VL]0 PID.txt: [PID]Value=XXXXX-XXXXX-XXXXX-XXXXX-XXXXX To modify the BCD of the installed image, and be able to easily repeat the second phase of install testing, I installed a second hard drive, and deployed WinPE to the second drive. By using F11 during boot to choose the boot drive, I could select booting from the second drive at any time. I have a variety WinPE v3 (Win7) based utility images, and I updated them to use WinPE v4 (Win8). In the process I lost the boot menu, and the first image in the menu automatically started booting. After some trial and error, I found the bootmenupolicy BCD option, and when set to legacy mode, the old style menu is back: bcdedit /set {default} bootmenupolicy legacy I installed Win8 on the primary drive, and during the reboot, instead of booting to the installed Win8 drive, I used F11 and booted to my secondary WinPE drive. From WinPE I modified the boot BCD to enable kernel debugging over the network: bcdedit -store c:\boot\bcd /set {default} nocrashautoreboot yesbcdedit -store c:\boot\bcd /set {default} debugtype netbcdedit -store c:\boot\bcd /set {default} hostip 3232235876bcdedit -store c:\boot\bcd /set {default} port 50000bcdedit -store c:\boot\bcd /set {default} key my.secret.debug.keybcdedit -store c:\boot\bcd /debug {default} yes This is equivalent to: bcdedit /dbgsettings net host:192.168.1.100 port:50000 key:my.secret.debug.key But unlike the dbgsettings command, this allows me to specify a BCD store. Also note that the IP address is stored as a single numeric value instead of the dotted IP format. While still in WinPE, I captured the state of the primary Win8 drive by making a drive image using Symantec Ghost, the real Ghost, currently sold as Symantec Ghost Solution Suite, not the same named but volume snapshot based Norton Ghost or Symantec System Recovery. By saving a drive image, I can easily change hardware or configurations, test the install starting at the second phase, reboot to the secondary WinPE drive using F11, restore the entire drive image, and try again, while leaving the kernel debug options intact. I tested with following hardware configurations in various permutations: With the kernel debugger attached, I captured the following crash details in WinDbg for NVidia based cards: VIDEO_TDR_FAILURE (116)Attempt to reset the display driver and recover from timeout failed.Arguments:Arg1: fffffa80211cd010, Optional pointer to internal TDR recovery context (TDR_RECOVERY_CONTEXT).Arg2: fffff8800782d0d8, The pointer into responsible device driver module (e.g. owner tag).Arg3: 0000000000000000, Optional error code (NTSTATUS) of the last failed operation.Arg4: 0000000000000002, Optional internal context dependent data. Debugging Details:------------------ FAULTING_IP: nvlddmkm+1ae0d8fffff8800782d0d8 4055 push rbp DEFAULT_BUCKET_ID: GRAPHICS_DRIVER_TDR_FAULT BUGCHECK_STR: 0x116 PROCESS_NAME: System CURRENT_IRQL: 0 STACK_TEXT: fffff88012c76078 fffff80166fef0ea : 0000000000000000 0000000000000116 fffff88012c761e0 fffff80166f734b8 : nt!DbgBreakPointWithStatusfffff88012c76080 fffff80166fee742 : 0000000000000003 fffff88012c761e0 fffff80166f73e90 0000000000000116 : nt!KiBugCheckDebugBreak+0x12fffff88012c760e0 fffff80166ef4144 : fffffa802094b100 fffff880021ee9c0 fffffa801f54e400 0000000000000000 : nt!KeBugCheck2+0x79ffffff88012c76800 fffff88004b33dcb : 0000000000000116 fffffa80211cd010 fffff8800782d0d8 0000000000000000 : nt!KeBugCheckEx+0x104fffff88012c76840 fffff88004b32518 : fffff8800782d0d8 fffffa80211cd010 fffff88012c76949 00000000000000c7 : dxgkrnl!TdrBugcheckOnTimeout+0xeffffff88012c76880 fffff88004a1e608 : fffffa80211cd010 fffff88012c76949 0000000000000000 0000000000000002 : dxgkrnl!TdrIsRecoveryRequired+0x168fffff88012c768b0 fffff88004a4d539 : 0000000000000000 fffff78000000320 0000000000000000 fffffa801f54e400 : dxgmms1!VidSchiReportHwHang+0x438fffff88012c769b0 fffff88004a4ba49 : fffffa8000000002 fffffa801f54e400 fffffa801f54e840 fffffa801f54e840 : dxgmms1!VidSchiCheckHwProgress+0xe5fffff88012c76a00 fffff88004a16fe5 : ffffffffff676980 0000000000000001 fffff88012c76b69 fffffa801f54e400 : dxgmms1!VidSchiWaitForSchedulerEvents+0x20dfffff88012c76aa0 fffff88004a4b646 : 0000000000000000 000000000000000f fffffa801f54e400 fffffa801f54e400 : dxgmms1!VidSchiScheduleCommandToRun+0x289fffff88012c76bd0 fffff80166e9b521 : fffffa801f5abb00 fffffa801f54e400 fffff88003b01140 0000000006a21e1e : dxgmms1!VidSchiWorkerThread+0xcafffff88012c76c10 fffff80166ed9dd6 : fffff88003af5180 fffffa801f5abb00 fffff88003b01140 fffffa8019aac040 : nt!PspSystemThreadStartup+0x59fffff88012c76c60 0000000000000000 : fffff88012c77000 fffff88012c71000 0000000000000000 0000000000000000 : nt!KiStartSystemThread+0x16 STACK_COMMAND: .bugcheck ; kb FOLLOWUP_IP: nvlddmkm+1ae0d8fffff8800782d0d8 4055 push rbp SYMBOL_NAME: nvlddmkm+1ae0d8 FOLLOWUP_NAME: MachineOwner MODULE_NAME: nvlddmkm IMAGE_NAME: nvlddmkm.sys DEBUG_FLR_IMAGE_TIMESTAMP: 4fdf93d7 FAILURE_BUCKET_ID: 0x116_IMAGE_nvlddmkm.sys BUCKET_ID: 0x116_IMAGE_nvlddmkm.sys With the kernel debugger attached, I captured the following crash details in WinDbg for ATI based cards: VIDEO_TDR_FAILURE (116)Attempt to reset the display driver and recover from timeout failed.Arguments:Arg1: fffffa801ed114d0, Optional pointer to internal TDR recovery context (TDR_RECOVERY_CONTEXT).Arg2: fffff8800725cefc, The pointer into responsible device driver module (e.g. owner tag).Arg3: 0000000000000000, Optional error code (NTSTATUS) of the last failed operation.Arg4: 000000000000000d, Optional internal context dependent data. Debugging Details:------------------ FAULTING_IP: atikmpag+8efcfffff8800725cefc 4055 push rbp DEFAULT_BUCKET_ID: GRAPHICS_DRIVER_TDR_FAULT BUGCHECK_STR: 0x116 PROCESS_NAME: System CURRENT_IRQL: 0 STACK_TEXT: fffff88006fa9ee8 fffff803e6ff20ea : 0000000000000000 0000000000000116 fffff88006faa050 fffff803e6f764b8 : nt!DbgBreakPointWithStatusfffff88006fa9ef0 fffff803e6ff1742 : 0000000000000003 fffff88006faa050 fffff803e6f76e90 0000000000000116 : nt!KiBugCheckDebugBreak+0x12fffff88006fa9f50 fffff803e6ef7144 : fffffa801e2df4e0 fffff880020b99c0 fffffa801d31f010 0000000000000000 : nt!KeBugCheck2+0x79ffffff88006faa670 fffff88004d31dcb : 0000000000000116 fffffa801ed114d0 fffff8800725cefc 0000000000000000 : nt!KeBugCheckEx+0x104fffff88006faa6b0 fffff88004d30548 : fffff8800725cefc fffffa801ed114d0 fffff88006faa7b9 0000000000000180 : dxgkrnl!TdrBugcheckOnTimeout+0xeffffff88006faa6f0 fffff88004c11608 : fffffa801ed114d0 fffff88006faa7b9 000000000000000f fffffa801d31f8f8 : dxgkrnl!TdrIsRecoveryRequired+0x198fffff88006faa720 fffff88004c459f9 : 0000000000000001 fffff88006faa8a0 fffff88006faa920 0000000000000000 : dxgmms1!VidSchiReportHwHang+0x438fffff88006faa820 fffff88004c3ff72 : fffffa801d31f010 fffff78000000320 fffffa801d31f770 fffffa801d31f010 : dxgmms1!VidSchWaitForCompletionEvent+0x411fffff88006faa8e0 fffff88004c4206c : fffffa801d31f010 fffffa801d31f450 fffffa801d31f450 0000000000000000 : dxgmms1!VidSchiWaitForEmptyHwQueue+0x9afffff88006faa9d0 fffff88004c3ea85 : 0000000000000000 fffffa801d31f010 fffffa801d31f450 0000000000000000 : dxgmms1!VidSchiSuspend+0x74fffff88006faaa00 fffff88004c09fe5 : ffffffffff676980 0000000000000001 fffff88006faab69 fffffa801d31f010 : dxgmms1!VidSchiWaitForSchedulerEvents+0x249fffff88006faaaa0 fffff88004c3e646 : 0000000000000000 fffffa801d585660 fffffa801d44d7f0 fffffa801d31f010 : dxgmms1!VidSchiScheduleCommandToRun+0x289fffff88006faabd0 fffff803e6e9e521 : fffffa801d6b9b00 fffffa801d31f010 fffff88003932140 0000000004d91ecb : dxgmms1!VidSchiWorkerThread+0xcafffff88006faac10 fffff803e6edcdd6 : fffff88003926180 fffffa801d6b9b00 fffff88003932140 fffffa8019ac7500 : nt!PspSystemThreadStartup+0x59fffff88006faac60 0000000000000000 : fffff88006fab000 fffff88006fa5000 0000000000000000 0000000000000000 : nt!KiStartSystemThread+0x16 STACK_COMMAND: .bugcheck ; kb FOLLOWUP_IP: atikmpag+8efcfffff8800725cefc 4055 push rbp SYMBOL_NAME: atikmpag+8efc FOLLOWUP_NAME: MachineOwner MODULE_NAME: atikmpag IMAGE_NAME: atikmpag.sys DEBUG_FLR_IMAGE_TIMESTAMP: 4fdf9279 FAILURE_BUCKET_ID: 0x116_IMAGE_atikmpag.sys BUCKET_ID: 0x116_IMAGE_atikmpag.sys This was not really helping me much, and I decided to repeat the tests but use the checked build of Windows 8 to help troubleshoot. With the kernel debugger attached, I captured the following ASSERT during the boot: Windows 8 Kernel Version 9200 MP (1 procs) Checked x64Built by: 9200.16384.amd64chk.win8_rtm.120725-1247Machine Name:Kernel base = 0xfffff8020e01d000 PsLoadedModuleList = 0xfffff8020e760ac0System Uptime: 0 days 0:00:06.228 (checked kernels begin at 49 days)Assertion: The BIOS has reported inconsistent resources (_CRS). Please upgrade your BIOS.ACPI!PnpBiosGetDeviceResourceList+0x15e:fffff880012c3c2a cd2c int 2Ch...Unknown bugcheck code (0)Unknown bugcheck descriptionArguments:Arg1: 0000000000000000Arg2: 0000000000000000Arg3: 0000000000000000Arg4: 0000000000000000 Debugging Details:------------------ PROCESS_NAME: System FAULTING_IP: ACPI!PnpBiosGetDeviceResourceList+15efffff880012c3c2a cd2c int 2Ch ERROR_CODE: (NTSTATUS) 0xc0000420 - An assertion failure has occurred. EXCEPTION_CODE: (NTSTATUS) 0xc0000420 - An assertion failure has occurred. DEFAULT_BUCKET_ID: WIN8_DRIVER_FAULT BUGCHECK_STR: 0x0 CURRENT_IRQL: 0 LOCK_ADDRESS: fffff8020e7c5d60 -- (!locks fffff8020e7c5d60) Resource @ nt!PiEngineLock (0xfffff8020e7c5d60) Exclusively ownedThreads: fffffa8019a36040-01<*> 1 total locks, 1 locks currently held PNP_TRIAGE: Lock address : 0xfffff8020e7c5d60Thread Count : 1Thread address: 0xfffffa8019a36040Thread wait : 0x105eccd4 LAST_CONTROL_TRANSFER: from fffff880012b736f to fffff880012c3c2a STACK_TEXT: fffff880009b4b30 fffff880012b736f : fffffa8023a9e900 fffff880012a7e01 fffff880009b4c08 fffff880012a7e70 : ACPI!PnpBiosGetDeviceResourceList+0x15efffff880009b4bd0 fffff8800125acba : fffffa8023a9e900 fffffa8019ac54c0 fffff880012a7e70 fffffa801f477010 : ACPI!ACPIBusIrpQueryResourceRequirements+0x8bfffff880009b4c50 fffff8020e91b6a4 : fffffa8023a9e900 fffffa8019ac54c0 fffff880009b4db0 fffffa8023a9e900 : ACPI!ACPIDispatchIrp+0x2a6fffff880009b4cf0 fffff8020e91cd1b : fffffa8023a9e900 fffff880009b4db0 00000001c00000bb 0000000000000000 : nt!IopSynchronousCall+0x10cfffff880009b4d80 fffff8020e915bdb : fffffa8023a9e900 fffff880009b4e50 fffffa8023a4f850 000000000000001e : nt!PpIrpQueryResourceRequirements+0x5ffffff880009b4e10 fffff8020e91748d : fffffa8023a9b8e0 0000000000000000 ffffffff80000218 fffffa8023a9b8e0 : nt!PiQueryResourceRequirements+0x47fffff880009b4ea0 fffff8020e91a1f2 : fffffa8023a9b8e0 fffffa8023a9b8e0 0000000000000001 0000000000000000 : nt!PiProcessNewDeviceNode+0x159dfffff880009b5070 fffff8020e08feb5 : fffffa8019adcd20 0000000000000000 fffff880009b5358 0000000000000000 : nt!PipProcessDevNodeTree+0x1fefffff880009b5310 fffff8020e08fb59 : 0000000000000000 0000000000000000 0000000000000000 fffffa8037e19cc0 : nt!PnpDeviceActionWorker+0x345fffff880009b53d0 fffff8020ed4010d : 0000000000000000 fffff8a000000007 fffff8a000f08c00 0000000000000000 : nt!PnpRequestDeviceAction+0x2edfffff880009b5420 fffff8020ed3b39d : fffff8020d536800 fffff8020e7c83c0 0000000000000006 fffff8020d536800 : nt!IopInitializeBootDrivers+0x905fffff880009b5650 fffff8020ed2deb5 : fffff8020d536800 0000000000000000 fffff8020d536800 fffff8020d51ebf0 : nt!IoInitSystem+0xb5dfffff880009b59b0 fffff8020e82d013 : fffff8020d536800 fffffa8019a36040 0000000000000000 fffffa8019ab3040 : nt!Phase1InitializationDiscard+0x1899fffff880009b5bc0 fffff8020e1b289e : fffff8020d536800 fffff8020d536800 0000000000000000 0000000000000000 : nt!Phase1Initialization+0x13fffff880009b5bf0 fffff8020e24ef96 : fffff8020e82d000 fffff8020d536800 fffff8020e6c6180 00000000f8ffffff : nt!PspSystemThreadStartup+0x1a2fffff880009b5c60 0000000000000000 : fffff880009b6000 fffff880009b0000 0000000000000000 0000000000000000 : nt!KiStartSystemThread+0x16 STACK_COMMAND: kb FOLLOWUP_IP: ACPI!PnpBiosGetDeviceResourceList+15efffff880012c3c2a cd2c int 2Ch SYMBOL_STACK_INDEX: 0 SYMBOL_NAME: ACPI!PnpBiosGetDeviceResourceList+15e FOLLOWUP_NAME: MachineOwner MODULE_NAME: ACPI IMAGE_NAME: ACPI.sys DEBUG_FLR_IMAGE_TIMESTAMP: 50109dd0 BUCKET_ID_FUNC_OFFSET: 15e FAILURE_BUCKET_ID: 0x0_ACPI!PnpBiosGetDeviceResourceList BUCKET_ID: 0x0_ACPI!PnpBiosGetDeviceResourceList This is interesting, the kernel ASSERT’s on a problem reported by the BIOS. I contacted SuperMicro support, they said they will investigate the BIOS failure, and they suggested I try to use PCIe slot #3 instead of slot #5. The motherboard manual mentions that slots #1, #2, and #3 are to be used if CPU #1 is installed, and slots #4, #5, and #6 to be used only if CPU #2 is installed. I have both processors installed, so not using the more conveniently located slot #5 never came to mind. I moved the graphic card to CPU #1 slot #3, and voila, install succeeded and Windows 8 was up and running! I repeated the checked build test with the graphic card in slot #3, and the same BIOS ASSERT error was reported, so the BIOS ASSERT seems to be unrelated to the ACPI_TDR_FAILURE error. This was a very frustrating problem, and I still don’t understand the root cause, but I am happy to be able to finally switch both workstations to Windows 8. ## WordPress.com 404 With Blogger Permalinks Part of the research I did before migrating from Blogger to WordPress.com, was to make sure that current Blogger permalinks will resolve correctly once the old posts were imported into WordPress.com. At the time all seemed fine, but soon after migrating, I received alerts from Google Webmaster Tools that there is an increase in site errors, specifically 404 errors. Some background: Permalinks are the URL’s that point directly to specific posts on the blog. These URL’s are known by search engines, are shared on forums, and are basically the static address of posts. Blogger and WordPress.com use different styles of permalinks. WordPress.com allows some customization of permalinks, but unlike WordPress.org, there is no support for custom plugins to handle rewrites for permalinks, 302’s or 404’s. Although not documented anywhere, WordPress.com does support Blogger style permalinks, and will correctly redirect the Blogger style link to the WordPress.com style page. As an example, see the links below, one for Blogger and one for WordPress.com: http://blogdotinsanegenius.blogspot.com/2012/06/looks-can-be-deceiving.html https://blogdotinsanegenius.wordpress.com/2012/06/looks-can-be-deceiving Search engines will know the link using the old blogger style URL, and both styles of links will correctly resolve to the current page: https://blog.insanegenius.com/2012/06/19/looks-can-be-deceiving https://blog.insanegenius.com/2012/06/looks-can-be-deceiving.html So why is it that Google Webmaster Tools reported a suddenly spike in 404’s? By reviewing the links that report 404, I noticed that the permalink format of certain posts on WordPress.com was slightly different to the Blogger permalinks. http://blogdotinsanegenius.blogspot.com/2009/10/hitachi-a7k2000-and-seagate-barracude.html http://blogdotinsanegenius.blogspot.com/2010/05/zotac-xboxhd-id11-mkv-h264-video.html http://blogdotinsanegenius.blogspot.com/2008/03/printing-from-network.html https://blogdotinsanegenius.wordpress.com/2009/10/11/hitachi-ultrastar-and-seagate-barracude-lp-2tb-drives/ https://blogdotinsanegenius.wordpress.com/2010/05/28/zotac-xboxhd-id11-mkv-h-264-video-playback-performance/ https://blogdotinsanegenius.wordpress.com/2008/03/30/printing-from-the-network/ Notice the difference? Blogger appears to keep links short, and remove words like “the” and “and”. I contacted WordPress.com support, and they provided a manual solution. They suggested that I modify the “slug” of each 404 post to match the Blogger style permalink. This resolved the problem with the top 404’s, but I would have expected the Blogger import plugin to take care of this for me. But, I soon received another alert email from Google Webmaster Tools, and this time the 404 posts looked a bit different. Notice that all the links contain parameters in the URL (I think these are old style Google Analytics parameters), and without the parameter the redirect works, but with any parameters the redirect fails. https://blog.insanegenius.com/2009/09/western-digital-re4-gp-2tb-drive.html https://blog.insanegenius.com/2009/09/western-digital-re4-gp-2tb-drive.html?m=1 I again contacted WordPress.com support, and I am still awaiting a resolution. [Update: 9 August 2012] Just got an email from WordPress.com support, the problem with parameters is fixed, thank you. ## SuperMicro Beta BIOS supports Windows 8 and Server 2012 In a previous post I reported that my SuperMicro SuperWorkstation 7047A-T failed to install Windows 8 or Windows Server 2012 due to a ACPI_BIOS_ERROR. I contacted SuperMicro support, and I was informed that new BIOS releases are on their way that will support Windows 8 and Server 2012. This morning I received an email from SuperMicro, with a new Beta BIOS for the X9DAi motherboard used in the 7047A-T. The new BIOS allowed me to install Windows 8 and Server 2012. I used a DOS bootable USB key, and installed the new BIOS. The 7047A-T has USB ports on the back and on the front of the case. The ports on the front are all USB3, and it is not possible to boot from these ports, at least I have not yet found a configuration that allows booting from USB3 ports. I tried using USB2 keys and, my newest Kingston DataTraveler HyperX 3.0 super fast USB3 keys, the BIOS does not list any boot devices in these USB3 ports. To boot from USB you have to plug the USB key in one of the rear USB2 ports. The new BIOS version is “1.0 beta”, compilation date “7/23/2012”. The BIOS screen looks like the more modern AMI EFI BIOS’s I’ve seen in other devices, i.e. the thin font instead of the classic console font. I performed a “Restore Optimized Defaults”, and then went through the options to see what has changed and what is new. The [Advanced] [Chipset Configuration] [North Bridge] [IOH Configuration] now sets all PCIe busses to GEN3, the old BIOS defaulted to GEN2. The [Advanced] [SATA Configuration] now enabled hot plug on all ports, the old BIOS defaulted to hot plug disabled. The [Advanced] [Boot Feature] ads a new power configuration item called “EuP”. This seems to be related to EU Directive 2005/32/EC: EU Directive 2005/32/EC enacted by the European Union member countries dictates that after January 1, 2010, no computer or other energy using product (EuP) sold in the member countries may dissipate more than 1 Watt in the standby (S5) state. I measured the power utilization, and the machine uses 2W when powered off, 140W at idle in Windows 8 desktop, and 7W while sleeping. I updated my Windows 8 USB key to the latest build (I have access to), booted from the USB key, and installed Windows 8 without any major issues. I had swapped the NVidia Quadro 4000 for a faster ATI FirePro V7900. The v1.0 BIOS worked fine with the Quadro 4000, but after installing the V7900, the screen powered on and Windows 7 started booting before I had a chance to see the BIOS screen. After installing the new Beta BIOS, the V7900 works as expected and I can see the BIOS screen during POST. This is a note for ATI; please make sure your VGA driver install UI fits on a 640×480 display. When I swapped the Quadro 4000 for the V7900, and rebooted into Windows 7, I booted into a 640×480 16 color screen. Imagine my frustration trying to guess which button has focus when you can only see the top half of the ATI driver installer. Windows 8 automatically installed drivers for the V7900. The only driver Windows 8 did not automatically install is the C600 chipset SAS driver. I installed the Intel Rapid Storage Technology Enterprise (RSTe) drivers, and that solved that problem. While running Windows 7 on this machine, and running the Windows Experience Index Assessment, the test would always crash. The same test in Windows 8 completed successfully. I found the 2D and 3D results to be disappointing, and I tried to replace the “ATI FirePro V (FireGL V) Graphics Adapter (Microsoft Corporation – WDDM v1.20)” driver with the ATI Windows 8 Consumer Preview driver. Although the release notes indicate that the V7900 is supported, the driver installation failed with an unsupported hardware error. I’ll have to wait for newer Windows 8 drivers from ATI to see if the test scores improve. I’m quite happy that I can use my new machines with Windows 8. I just wish SuperMicro solved the BIOS incompatibility problems long ago, after all, it has been almost two years since the Windows 8 pre-release program started, and almost a year since the release of the public developer preview. ## Debugging Windows 8 Install BSOD In my last post I described how to prevent Windows from automatically restarting when encountering a BSOD during the OS install process. This allowed me to see the ACPI_BIOS_ERROR fault code while installing Windows 8 on my new SuperMicro workstation. The new Windows 8 BSOD page looks friendly, but no longer displays any error parameters other than the main fault code. In order to get additional details of the crash, I had to hook up a kernel debugger to the machine. Windows 8 adds USB3 and TCPIP kernel debug support, and I will describe how I used the TCPIP network option to capture details of the crash. First thing to do is prepare our tools, download the Windows 8 Debugging Tools for Windows package, and the Windows 8 Symbols. Unfortunately the debugging tools are no longer available as a standalone download, and you need to install the SDK or WDK on a Windows 8 system in order to get them, but you can choose to only install the debugging tools. Once you installed the debugging tools on one machine, you can copy the MSI installers or the directory to any other machines, including Windows 7 systems. You will find the tools in the “C:\Program Files (x86)\Windows Kits\8.0\Debuggers” folder. Microsoft is pretty good at publishing symbols for most released versions of their products to their public symbol server, but I prefer to extract the symbols to a working directory on my machine, or to upload the symbols to our internal symbol server. You can install the downloaded symbols MSI package directly, or use the following command to extract the symbols from the MSI file to a location on disk. Run an elevated (right click run as administrator) command prompt, and type: msiexec /a [symbol msi file name] /qb targetdir="[output directory]" Next we need to enable kernel network debugging in the BCD options. This needs to be done on a Windows 8 machine as the network debugging command is not supported in older versions of BCDEdit. I should also call out that network debugging support is required for hardware logo certification, but not all current adapters support it. Insert the bootable Windows 8 USB key, run an elevated command prompt, and type: bcdedit –store [usb key drive]:\boot\bcd /dbgsettings net hostip:[IP of WinDbg machine] port:50000 BCDEdit will output the connection security key that is required by WinDbg. Start WinDbg, and enable network kernel debugging, entering the port number and security key. Boot the target machine, you will see the target machine connecting to WinDbg: Microsoft (R) Windows Debugger Version 6.2.8400.0 AMD64Copyright (c) Microsoft Corporation. All rights reserved.Using NET for debuggingOpened WinSock 2.0Waiting to reconnect...Connected to target 192.168.1.106 on port 50000 on local IP 192.168.1.100.Connected to Windows 8 8400 x64 target at (Fri Jul 20 11:07:21.583 2012 (UTC - 7:00)), ptr64 TRUEKernel Debugger connection established. And then the ACPI_BIOS_ERROR crash: 25: kd> !analyze -v******************************************************************************** ** Bugcheck Analysis ** ******************************************************************************** ACPI_BIOS_ERROR (a5)The ACPI Bios in the system is not fully compliant with the ACPI specification.The first value indicates where the incompatibility lies:This bug check covers a great variety of ACPI problems. If a kernel debuggeris attached, use "!analyze -v". This command will analyze the precise problem,and display whatever information is most useful for debugging the specificerror.Arguments:Arg1: 0000000000000003, ACPI_FAILED_MUST_SUCCEED_METHOD ACPI tried to run a control method while creating device extensions to represent the ACPI namespace, but this control method failed.Arg2: fffffa8019f2f288, The ACPI Object that was being runArg3: ffffffffc0000034, return value from the interpreterArg4: 00000000494e495f, Name of the control method (in ULONG format) Debugging Details:------------------ ACPI_OBJECT: fffffa8019f2f288 DEFAULT_BUCKET_ID: WIN8_DRIVER_FAULT BUGCHECK_STR: 0xA5 PROCESS_NAME: System CURRENT_IRQL: 0 LAST_CONTROL_TRANSFER: from fffff803ca1e617a to fffff803ca0e5870 STACK_TEXT: fffff880053eb418 fffff803ca1e617a : 0000000000000000 00000000000000a5 fffff880053eb580 fffff803ca16b930 : nt!DbgBreakPointWithStatusfffff880053eb420 fffff803ca1e57d2 : 0000000000000003 00000000494e495f fffff803ca168810 00000000000000a5 : nt!KiBugCheckDebugBreak+0x12fffff880053eb480 fffff803ca0eb044 : 00000000c0000034 fffff88001038255 fffffa801a50fe78 00000000c0000034 : nt!KeBugCheck2+0x79ffffff880053ebba0 fffff88001043949 : 00000000000000a5 0000000000000003 fffffa8019f2f288 ffffffffc0000034 : nt!KeBugCheckEx+0x104fffff880053ebbe0 fffff8800103bded : 0000000000000000 0000000000000000 0000000000008004 00000000c0000034 : ACPI!ACPIBuildCompleteMustSucceed+0x39fffff880053ebc20 fffff880010346bd : fffffa801a500000 0000000000008000 0000000000000000 fffffa8037e80000 : ACPI!AsyncCallBack+0x7ffffff880053ebc50 fffff88001034f56 : fffffa801a500000 fffff88001072be0 0000000000000000 0000000000000002 : ACPI!RunContext+0x141fffff880053ebc90 fffff880010386e3 : fffffa8019b1c3a0 0000000000000000 0000000000000000 fffffa8019a35258 : ACPI!InsertReadyQueue+0xd6fffff880053ebcc0 fffff8800103862a : fffff803ca2eb490 fffff88001072be0 0000000000000000 00000000546c6d41 : ACPI!RestartCtxtPassive+0x2ffffff880053ebcf0 fffff803ca0cb181 : fffffa8019e06b00 0000000000000080 fffff88004ac6540 0000000000000000 : ACPI!ACPIWorkerThread+0xeafffff880053ebd50 fffff803ca0dae26 : fffff88004aba180 fffffa8019e06b00 fffff88004ac6540 fffffa8019a8f940 : nt!PspSystemThreadStartup+0x59fffff880053ebda0 0000000000000000 : fffff880053ec000 fffff880053e6000 0000000000000000 0000000000000000 : nt!KiStartSystemThread+0x16 STACK_COMMAND: kb FOLLOWUP_IP: ACPI!ACPIBuildCompleteMustSucceed+39fffff88001043949 cc int 3 SYMBOL_STACK_INDEX: 4 SYMBOL_NAME: ACPI!ACPIBuildCompleteMustSucceed+39 FOLLOWUP_NAME: MachineOwner MODULE_NAME: ACPI IMAGE_NAME: ACPI.sys DEBUG_FLR_IMAGE_TIMESTAMP: 4fe6a2b1 BUCKET_ID_FUNC_OFFSET: 39 FAILURE_BUCKET_ID: 0xA5_ACPI!ACPIBuildCompleteMustSucceed BUCKET_ID: 0xA5_ACPI!ACPIBuildCompleteMustSucceed Followup: MachineOwner Even with all the crash details, it still doesn’t really help me make progress, as it has been two days since I logged the support request with SuperMicro, and no response yet. ## CrashPlan Memory Utilization I’ve been using CrashPlan as an online backup solution for quite some time, and it works really well. I like the fact that I can subscribe to the consumer plan, with almost 3.5TB of data backed up, and that the backup client installs on a server OS. Many of the other “unlimited” backup providers I tested have restrictions in place that makes such a setup impossible. CrashPlan sends email notifications about backup status, and I noticed that something was wrong with the backup: I logged onto the machine, opened the main UI, and after a few seconds the UI just closed. opened it again, same thing, after about 15s the UI closed. My initial thoughts were that it is a crash, but on attaching a debugger, the exit call stack showed that the process was cleanly terminated after receiving a signal. On looking at the NT eventlog I could see that the service was restarting about every 15s: The CrashPlan Backup Service service entered the stopped state. The CrashPlan Backup Service service entered the running state. The CrashPlan Backup Service service entered the stopped state. The CrashPlan Backup Service service entered the running state. The CrashPlan Backup Service service entered the stopped state. The CrashPlan Backup Service service entered the running state. The service wasn’t crashing, it was externally being stopped and restarted. I looked in the CrashPlan directory, and I found several log files with a naming like restart_1342296082496.log. The contents of these files looked like this: Sat 07/14/2012 13:01:22.53 : "C:\Program Files\CrashPlan\bin\restart.bat" ECHO is off. Sat 07/14/2012 13:01:22.53 : APP_BASE_NAME=CrashPlan Sat 07/14/2012 13:01:22.53 : APP_DIR=C:\Program Files\CrashPlan ECHO is off. Sat 07/14/2012 13:01:22.53 : Stopping CrashPlanService The CrashPlan Backup Service service is stopping. The CrashPlan Backup Service service was stopped successfully. Sat 07/14/2012 13:01:25.05 : Sleeing 15 seconds... Pinging 127.0.0.1 with 32 bytes of data: Reply from 127.0.0.1: bytes=32 time<1ms TTL=128 Reply from 127.0.0.1: bytes=32 time<1ms TTL=128 Reply from 127.0.0.1: bytes=32 time<1ms TTL=128 Reply from 127.0.0.1: bytes=32 time<1ms TTL=128 Ping statistics for 127.0.0.1: Packets: Sent = 15, Received = 15, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms Sat 07/14/2012 13:01:39.08 : Starting CrashPlanService The CrashPlan Backup Service service was started successfully. ECHO is off. Sat 07/14/2012 13:01:39.13 : Exiting... I looked for a newer version, but 3.2.1 was the latest version. I logged a support ticket with CrashPlan, but I continued my investigation. I found a log file service.log.0, several MB in size, and inside it I found this: [07.14.12 12:32:39.480 ERROR QPub-BackupMgr backup42.service.backup.BackupController] OutOfMemoryError occurred...RESTARTING! message=OutOfMemoryError in BackupQueue! So it seems that the service is running out of memory. I now had a few good keywords to search on, and I found this post of a user with the same problem. At about the same time I received a reply from CrashPlan support, not bad for weekend service, with the same solution. The CrashPlan backup service and desktop applications are Java apps, and as such the maximum amount of memory they use are capped by configuration. I have had similar problems with other memory hungry Java apps, like Jaikoz, that simply fail unless you increase the memory limit. To fix the problem, shutdown the service, open the CrashPlanService.ini file in the program directory, and increase the maximum memory utilization parameter to 2GB, the default is 512MB, and restart the service: Virtual Machine Parameters=-Xrs -Xms15M –Xmx2048M After upping the memory all seemed well, and the service has been running for more than a day. But, I wanted to know just how much memory is CrashPlan using, and it turns out to be insane. Here are the current stats for the amount of data I backup, as well as the resource utilization by the backup service and desktop app: As you can see, the desktop app’s peak private bytes exceed 250MB, and the service exceeds 1.3GB, that’s right 1.3GB of memory! Those numbers are simply outrageous. ## NCP VPN not quite Windows 7 compatible I got so frustrated with the NCP VPN client software, specifically a recent update, that I decided to let my frustration out by writing about it. For a long time I used the, IT approved, Cisco VPN client to access our corporate network. And as the OS technology moved along, so did my systems, meaning Vista, Windows 7, and 64-bit. While, for the most part, our IT approved systems remained to be only 32-bit XP. Cisco, for some reason, maybe they are representative of IT organizations as whole, was late to support Vista, was late to support Windows 7, and for the longest time never supported x64. The only Cisco compatible alternative on Windows 7 x64, was the NCP VPN client. But, at a cost,$144, per machine, very expensive.
I recently read that almost 50% of Windows 7 machines are 64-bit, and I recently read that Cisco announced VPN client support for x64 on Vista and Windows 7. I am sure this is not a coincidence.
But I digress, this post is not about Cisco, it is about the NCP VPN client.
Where to start?
The NCP software is intrusive, every time you login it shows a splashscreen, and the splashscreen remains topmost, blocking anything behind it, until it closes, by itself. I contacted NCP support, complaining about the intrusion, and they told me that it is necessary to run their software at login so that they can validate the license. I replied that validating the license need not happen at every login, and certainly should not interfere with my system. They said I could search the internet and find out how other people disabled their software.
This means a few things to me; they do not value usability, they acknowledge there is a problem, yet they do not offer a solution.
Imagine if every application you install on your system decides it is a good idea to show a splashscreen when you login.
Here is the splashscreen that pops up on every login:
In case you are wondering how to disable NCP from running at startup, they install three user session startup entries under [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Run], delete or rename them
While we’re on the topic of usability, this application’s UI was probably not designed by Windows developers, or certainly not somebody that knows anything about standard Windows user interface design and principles.
In the main UI, shown below, how do you connect, where is the connect button, do you click the red button, no you need to click the gray area next to the red button. They probably though it looks cool.
Every time you login the application starts and shows its UI. How would you normally look for options in a windows app; probably [Options], or [Tools][Options], or [File][Options]. No, you need to click on [View][Autostart][No Autostart], what does the [View] menu have to do with [Autostart]?
And in case you were wondering, no, disabling autostart does not disable the splashcreen.
So what is it that made me mad enough to write this post?
I received an email that a new version was released, and the software offers a built in check for update mechanism by clicking [Help][Search for Updates]:
How big is that update? 23.792 kByte, really, 24 kilobyte, or what is a lowercase k in kByte? Or is that really 23,729 KB as in 24 megabyte?
And then the Windows Program Compatibility Assistant pops up:
I contacted support, got an email that said no other users had reported this problem, and they asked if I am an admin on the system, but before I could respond, I got another email that said they reproduced the problem, and that I should download and install the update from the website.
And then the Windows Program Compatibility Assistant pops up:
You may think it is a problem with my system, I repeated the same steps on a second system, that is how I captured the screenshots, and I ran Microsoft Process Monitor to record what is happening.
As a developer, that is familiar with writing Windows 7 compatible software, I know what is going on here.
The NCP software installs:
Three startup items: NcpBudgetGui, NcpPopup, NcpRsuGui
Three services: ncpclcfg, ncprwsnt, NcpSec
Two drivers: ncpfilt, ncplelhp
The NCP UI process is called NCPMON.exe, and is launched by explorer, runs non-elevated, at medium IL. It is the NCPMON.exe process that downloads and executes the update.
From the procmon log I can see that NCPMON.exe called CreateProcess() to launch the installer:
Date & Time: 7/21/2010 10:01:12 AM
Event Class: Process
Operation: Process Create
Result: SUCCESS
Path: C:\Users\Pieter Viljoen\AppData\Local\Temp\NCP_EntryCl_Win32_923_17.exe
TID: 6952
Duration: 0.0000000
PID: 6856
Command line: "C:\Users\Pieter Viljoen\AppData\Local\Temp\NCP_EntryCl_Win32_923_17.exe"
This will not work, the NCP_EntryCl_Win32_923_17.exe is an installer it has to “Run As Admin” (this is an InstallShield installer, and although it does not contain a Run As Admin manifest entry, the Windows Application Compatibility subsystem recognizes InstallShield installers, and automatically runs them with elevation required), this means that when you launch this EXE using ShellExecute(), or using Explorer, you will get a UAC elevation prompt, and if approved, the installer will run elevated, and the install succeed.
There is only one explanation of how NCP could ever have shipped this, their developers and QA test with UAC disabled on their test systems.
What about the appcompat warning after the install?
Microsoft requires that Windows Vista and Windows 7 compatible applications mark their compatibility in the installer manifest.
By inspecting the resources in the installer EXE, there is a manifest, but there is no compatibility manifest, as such, this error will always show on a Windows 7 system.
I have no explanation for how NCP could allow this to ship, ignorance?
It makes me mad that an ISV advertises Windows 7 compatibility, and ships software like this. It is companies like NCP that gives Windows a bad name, and drives companies like Apple, to enforce rigorous, sometimes draconian, quality and usability standards in order to protect their own brand.
## DELL 2408WFP loosing settings on power cycle
In my last post I discussed the calibration of my DELL 2408WFP monitors.
After calibration, and changing the monitor settings, the monitors looked pretty good, but I later found that the monitor colors looked all weird again.
It turns out that the monitors reverted to their default settings, invalidating the calibration.
It seems to me that as soon as my PC goes to sleep, or the monitors go into power saving mode, or powers off, that on turning back on they revert to default settings.
I found a relatively simple solution using EnTech mControl, not completely automated but close.
mControl allows you to save the current monitor settings to a profile, and allows you to restore those settings.
Here are the steps:
1. Install and run mControl.
2. Set mControl to automatically load when you login. Right click on the mControl tray icon and enable auto-load. This will add an entry in the startup program group.
4. Save your monitor profile. Open a command prompt, change to the mControl directory (“C:\Program Files (x86)\mControl\”), and run “mControl.exe /saveprofile Calibrate”. This will save the current monitor settings to a profile called “Calibrate”. You can use any profile name, I just used “Calibrate” as an example.
5. Edit the mControl startup item so that it automatically restores the monitor profile when mControl starts. Right click the mControl entry in your startup programs group, and edit the commandline to include the “/restoreprofile Calibrate” option. E.g. “”C:\Program Files (x86)\mControl\mControl.exe” /restoreprofile Calibrate”
Every time you login mControl will start and restore the monitor settings.
If you change the monitor settings, simply run “mControl /saveprofile Calibrate” again to save the updated settings.
Unfortunately this only works when you login, but if the monitors power down while you are logged in, e.g. sleep, you have to manually restore the settings.
I solved this by creating a text script file called “Monitor.Restore.Profile.cmd” on my desktop, and putting the restore command in the file, “”C:\Program Files (x86)\mControl\mControl.exe” /restoreprofile Calibrate”.
Now whenever the monitor settings need to be fixed, I just run this script and the settings are restored.
This seems to be a problem with the DELL 2408WFP monitors, and I would like to know if this is specific my to my setup, or if this happens to other people, leave me a comment and let me know.
[Update: 17 July 2009]
EnTech has enhanced mControl to support profiles right in the UI, including an “Autoexec” profile that will automatically restore the monitor settings on login and wake from sleep.
It works great.
## Amazon Unbox on x64 Vista
While shopping on Amazon I noticed that they were offering the Pilot of the Showtime series Nurse Jackie in HD for free, so I decided to give it a try.
The install (version 2.0.1.95) went smoothly, and the 1.3GB downloaded also completed pretty quickly, and I watched the show.
Ok, now I wanted to stop the Unbox player service from running and terminate the tray icon application, I have no need to have it running all the time.
I went to [Settings][Preferences], and unchecked the [Run the Amazon Unbox service when Windows starts] option.
I then right clicked on the tray icon and selected [Exit], the tray application launched “Amazon Unbox Config.exe stop” application, requiring UAC elevation, and promptly crashed with the following message:
An unhandled exception of type ‘System.BadImageFormatException’ occurred in Unknown Module.
Additional information: Could not load file or assembly ‘ADVWindowsClientAppRoot, Version=2.0.1.95, Culture=neutral, PublicKeyToken=091de1773ddefdbf’ or one of its dependencies. An attempt was made to load a program with an incorrect format.
I contacted Amazon support, and they provided this response:
Hello from Amazon.com.
I sincerely apologize for the trouble you’ve had using the Unbox Video Player. From your message, I understand you received an error relating to Windows being unable to load the correct file path.
I’ve researched the issue and suggest that you update the security components of your Microsoft operating system.
If using Microsoft’s update does not resolve your playback issue, I recommend uninstalling and reinstalling your .NET Framework.
The Microsoft .NET Framework includes a large library of coded solutions to common programming problems and a virtual machine that manages the execution of programs written specifically for the framework. The .NET Framework is a key Microsoft offering and is intended to be used by most new applications created for the Windows platform.
I hope you found this information useful.
I gave them the benefit of the doubt and tried to update the DRM components, it did not work.
I suspected I know what the problem was, and this problem reminded me of a similar problem with the Google Email Uploader on Vista x64.
My suspicions were confirmed after I used CorFlags to inspect the binaries:
CorFlags.exe “C:\Program Files (x86)\Amazon\Amazon Unbox Video\Amazon Unbox Config.exe”
Microsoft (R) .NET Framework CorFlags Conversion Tool. Version 3.5.21022.8
Version : v2.0.50727
PE : PE32
CorFlags : 9
ILONLY : 1
32BIT : 0
Signed : 1
CorFlags.exe “C:\Program Files (x86)\Amazon\Amazon Unbox Video\ADVWindowsClientAppRoot.dll”
Microsoft (R) .NET Framework CorFlags Conversion Tool. Version 3.5.21022.8
Version : v2.0.50727
PE : PE32
CorFlags : 11
ILONLY : 1
32BIT : 1
Signed : 1
The output indicated that the EXE file was compiled to run natively on any platform, i.e. x64 on x64 and x86 on x86, but the DLL was compiled to be x86 only.
Thus the EXE runs as x64 and tries to load a x86 binary, not allowed, causing the crash.
The CorFlags output and x64 migration is discussed in this MSDN blog post:
anycpu: PE = PE32 and 32BIT = 0
x86: PE = PE32 and 32BIT = 1
64-bit: PE = PE32+ and 32BIT = 0
To fix the problem I have to change the EXE attributes to only run in 32bit:
CorFlags.exe “C:\Program Files (x86)\Amazon\Amazon Unbox Video\Amazon Unbox Config.exe” /32BIT+ /Force
The “Force” flag is required because the binary is Authenticode signed, and after the header change the Authenticode signature is now invalid.
“CorFlags” is parts of the .NET / Platform SDK and can be downloaded from Microsoft.
After I made the changes to the EXE, I repeated the original steps, and no more crash.
I replied to Amazon with my findings, and I hope they make the necessary, and easy, changes to fully support x64.
|
# Thread: Planet Semirg and Planet Aniram
1. ## Planet Semirg and Planet Aniram
Planet Aniram is similar to Planet Semirg, both of which are perfect sphere. If the ratio of the length of Planet Aniram’s radius to the length of Planet Semirg’s radius is 3:4, then find the volume of Planet Semirg in cubic units if the volume of Planet Aniram is 135 cubic units.
I know how to find the ration, you divide by 3 but I don't know how to find the volume in cubic units.
2. ## Re: Planet Semirg and Planet Aniram
The formula of the volume of a sphere is (4*pi/3)*R^3. You said you know how calculate the ratios. Can you continue from there?
3. ## Re: Planet Semirg and Planet Aniram
Nadeshikol, you need to start showing any work you've been able to do. If you haven't been able to we'll give some hints, but you have to show some effort as well. This refers to your other four posts as well.
-Dan
4. ## Re: Planet Semirg and Planet Aniram
Assume planet Semirg's radius is R. What is its volume, in terms of R? Then planet Aniram's radius if (3/4)R. What is its volume, in terms of R? Divide the two volumes to find their ratio.
5. ## Re: Planet Semirg and Planet Aniram
Originally Posted by topsquark
Nadeshikol, you need to start showing any work you've been able to do. If you haven't been able to we'll give some hints, but you have to show some effort as well. This refers to your other four posts as well.
-Dan
I'm sorry! I will post any work I have done next time.
6. ## Re: Planet Semirg and Planet Aniram
I got 268.16 cubic units as the answer.
Work:
V= 4/3*pi*4^3
V= 4/3*3.14/1=12.56/3
V= about 4.19
V=4.19*4^3
V=268.16
7. ## Re: Planet Semirg and Planet Aniram
Originally Posted by Nadeshiko
I got 268.16 cubic units as the answer.
Work:
V= 4/3*pi*4^3
V= 4/3*3.14/1=12.56/3
V= about 4.19
V=4.19*4^3
V=268.16
8. ## Re: Planet Semirg and Planet Aniram
Originally Posted by votan
Hello! I don' think we have learned this kind of math yet. I mean the V and then a letter at the bottom.
9. ## Re: Planet Semirg and Planet Aniram
Originally Posted by Nadeshiko
Planet Aniram is similar to Planet Semirg, both of which are perfect sphere. If the ratio of the length of Planet Aniram’s radius to the length of Planet Semirg’s radius is 3:4, then find the volume of Planet Semirg in cubic units if the volume of Planet Aniram is 135 cubic units.
I know how to find the ration, you divide by 3 but I don't know how to find the volume in cubic units.
Does not matter what the form of similar simple solids is the volume scales as the cube of any linear dimension. So if the radii are in the ratio $a:b$ the volumes are in the ratio $a^3:b^3$.
The condition that they are both perfect spheres is redundant, that they are similar is sufficient.
.
10. ## Re: Planet Semirg and Planet Aniram
Originally Posted by Nadeshiko
Hello! I don' think we have learned this kind of math yet. I mean the V and then a letter at the bottom.
You used the V in your post of yesterday at 11:14 PM
|
# Solve for: x^2-22x+121
## Expression: ${x}^{2}-22x+121$
Write the expression as a product with the factors $x$ and $11$
${x}^{2}-2 \times x \times 11+121$
Write the number in the exponential form with an exponent of $2$
${x}^{2}-2 \times x \times 11+{11}^{2}$
Use ${a}^{2}-2ab+{b}^{2}={\left( a-b \right)}^{2}$ to factor the expression
${\left( x-11 \right)}^{2}$
Random Posts
Random Articles
|
# Definition of capacity of cut in a flow network
In the flow network below, an S-T cut is made.
The net flow across the cut is $12-4+11=19$.
The capacity of the cut is $12+14=26$. The "backwards" edge $(v_3,v_2)$ is not counted when calculating capacity.
Why isn't the capacity of a cut defined to be $(\text{capacity of forward edges}) - (\text{capacity of backwards edges})$? This is more intuitive.
|
Under the auspices of the Computational Complexity Foundation (CCF)
REPORTS > KEYWORD > ATTRIBUTE-EFFICIENT LEARNING:
Reports tagged with attribute-efficient learning:
TR09-060 | 4th June 2009
Harry Buhrman, David García Soriano, Arie Matsliah
#### Learning parities in the mistake-bound model.
We study the problem of learning parity functions that depend on at most $k$ variables ($k$-parities) attribute-efficiently in the mistake-bound model.
We design simple, deterministic, polynomial-time algorithms for learning $k$-parities with mistake bound $O(n^{1-\frac{c}{k}})$, for any constant $c > 0$. These are the first polynomial-time algorithms that learn $\omega(1)$-parities in ... more >>>
TR12-056 | 1st May 2012
Rocco Servedio, Li-Yang Tan, Justin Thaler
#### Attribute-Efficient Learning and Weight-Degree Tradeoffs for Polynomial Threshold Functions
Revisions: 1
We study the challenging problem of learning decision lists attribute-efficiently, giving both positive and negative results.
Our main positive result is a new tradeoff between the running time and mistake bound for learning length-$k$ decision lists over $n$ Boolean variables. When the allowed running time is relatively high, our new ... more >>>
ISSN 1433-8092 | Imprint
|
# Bindings
Bindings can be seen as a replacement for constants in the scope of functions. They don't enable us to do something completely new, but help to make things more clearly, as we can store the result of some expression through a binding.
## let binding
abstractCalculation :: Int -> Int -> IntabstractCalculation x y = let sum = x + y product = x * y in sum + product
The function above adds the sum of x & y to their product - nothing special. As you can see, with the let-block we can define constants (sum and product) and close the function with the "in" keyword, which kind of serves as return-statement. Hint: You are not forced to use the defined constants within the in-line.
## where binding
Using the where keyword we can declare a constant on top of our function which is later initialized. Finally, this constant will be returned from the function.
addNums :: Int -> Int -> IntaddNums x y = sum where sum = x + y
Yet, this is not a practical usecase for where. More common is to declare your constant as a complex type like a list or a tuple, and then return it.
sumAndProduct :: Int -> Int -> (Int, Int)sumAndProduct x y = (sum, product) where sum = x + y product = x * y
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## Slow magnetic relaxation of a ferromagnetic Ni(II)5 cluster with an S = 5 ground state.
Complex [Ni 5{pyCOpyC(O)(OMe)py} 2(O 2CMe) 4(N 3) 4(MeOH) 2].2MeOH.2.6H 2O ( 1.2MeOH.2.6H 2O) was synthesized by the reaction of Ni(O 2CMe) 2.4H 2O with pyCOpyCOpy and NaN 3 in refluxing MeOH. It crystallizes in the monoclinic C2/ c space group and consists of five Ni (II) atoms in a helical arrangement. Direct current magnetic susceptibility studies reveal ferromagnetic interactions between the Ni (II) ( S = 1) ions, stabilizing an S = 5 ground state. Alternating current susceptibility experiments revealed the existence of out-of-phase signals indicative of slow magnetic relaxation. Analysis of the signals showed that they are composite, suggesting more than one relaxation process, while analysis of their magnitudes suggests not all molecules undergo slow magnetic relaxation. Magnetization field-sweep experiments revealed hysteresis at 1.8 K, and magnetization decay experiments clearly verified the appearance of slow magnetic relaxation at that temperature.
DOI: 10.1021/ic801441d
Version: za2963e q8za3 q8zba q8zce q8zd8 q8zee q8zf7 q8zg6
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## eigenschmeigen 3 years ago n points are placed at random on the circumference of a circle, what is the probability that they all lie within a common semicircle?
1. satellite73
i have googled this question and there are many explanations, but i have to say i don't even really understand what it is asking
2. eigenschmeigen
think of placing points at random, now what is the probability that it is possible to cut the circle in half leaving all the points on one side, for example it is possible here: |dw:1333717099690:dw|but not here:|dw:1333717241684:dw|
3. UnkleRhaukus
if n=2 P=1 if n>3 P<1 ....
4. UnkleRhaukus
$P(n)$
5. eigenschmeigen
ill post my thoughts so far.
6. eigenschmeigen
trivially P(1) = 1
7. UnkleRhaukus
this question reminds me of Buffon's needle problem
8. eigenschmeigen
P(2) is also easy, but we can learn from it: 1 point, A is already there, so placing another point the only place which is questionable is 180 degrees from A , i dont know whether it counts but it doesnt matter as the probability of that position exactly is 0 , therefore P(2) =1
9. eigenschmeigen
now for three points
10. UnkleRhaukus
is P(3)=1/2?
11. UnkleRhaukus
the first two points are in the same semi circle always , the third is either in-between the or out-between them, equal chance/?
12. eigenschmeigen
yes i think so! maybe.. |dw:1333724818545:dw|
13. eigenschmeigen
placing C on the circle somewhere.. where is allowed?
14. eigenschmeigen
maybe its not 1/2 ...
15. UnkleRhaukus
1/2 in the worst case scenario, ie if the first two points are opposite
16. eigenschmeigen
|dw:1333725166177:dw| i think its $\frac{l}{(circumference)}$
17. eigenschmeigen
those lines from A and B are diameters
18. UnkleRhaukus
this is a good question . and i can see you are getting closer and closer, but for now i must go (you might want to check out the Buffon's needle problem for some hints
19. eigenschmeigen
thanks for the help
20. rym
50 percent
21. TuringTest
I agree, good question This is perhaps a good question for the meta-math section
22. eigenschmeigen
to anyone viewing i think (guessing) maybe i should find l in terms of theta , then use an integral to find P(theta from A diameter)
23. eigenschmeigen
whats the meta math section?
24. TuringTest
click the "mathematics" blue bar you will see it is a category
25. TuringTest
26. TuringTest
hard and irregular questions are found and solved there
27. eigenschmeigen
oh cool
28. TuringTest
but it can take a long time to get a response in that section, so take your pick keep "bumping" it here, or post in meta-math and wait...
29. eigenschmeigen
or both? hehe
30. TuringTest
in the meantime let me call on some who may be able to solve this: @across @JamesJ @Zarkon @Mr.Math @FoolForMath interesting probability problem (none are online right now it seems)
31. TuringTest
I'm not sure if you can post in both sections with the new "bump" system, but feel free to try :)
32. TuringTest
oh, mr.math is here after all maybe he has some nice thoughts on this
33. Mr.Math
I found this http://mathproblems.info/images/prob1.pdf
34. FoolForMath
35. TuringTest
I can almost understand the MSE one, but I can't read Mr.Math's answer... when will my brain grow up like that?
36. TuringTest
I can see how they're kinda the same...
37. eigenschmeigen
i understand FFMs but i am struggling with mr.maths , i understand what's going on in general, im just not following all of the maths there. i think i need more experience with continuous probability and expected values..
38. eigenschmeigen
gonna close it up now unless anyone has more to add, thanks guys for all your help :)
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# Geometry Angle Measurements
1. Oct 4, 2006
### Ebene
I'm doing test corrections for homework and we have to explain how to correct what we did wrong. I already have the answers I just need to know how to figure out the answer.
18. Find m<Q. The diagram is not to scale.
24. Find the value of x. The diagram is not to scale.
Given: <SRT is congruent to <STR, m<SRT=20, m<STU=4x
2. Oct 4, 2006
### HallsofIvy
Staff Emeritus
Well, the point is that you need to figure out how to do this. We'll give hints but you need to tells us what you understand about this problem. In the first one, think "Opposite Interior Angles" with parallel lines and "the sum of the angles in a triangle is _____". For the second one, what do you know about isosceles triangles?
3. Oct 4, 2006
18. m<Q = 60. Look at the 50 degrees. The angle opposite of that is also 50 degrees, because they are vertical angles. Then, because the two lines are parallel and are cut by a transversal, the alternate interior angles are congruent. So the angle below R is 50 degrees. 70+50 = 120, 180-120 = 60. Since they are vertical angles, then m<Q = 60.
24. $$x = 40$$. If $$m<SRT = 20$$, then $$m<STR = 20$$. So $$180-20 = 160 = 4x$$, $$x = 40$$
4. Oct 4, 2006
### Ebene
Yeah, I did all of the ones I could and I spent about 30 minutes trying to figure these two out and couldn't. Thanks
5. Oct 4, 2006
### Ebene
Thanks so much, this helped a lot!
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# Math Help - How many atoms are there in 11.0g or CO2?
1. ## How many atoms are there in 11.0g or CO2?
How many atoms are there in 11.0g or CO2?
Any help is appreciated, I am still learning this, so if you do decide to help would you please give brief explinations! Thank you!
2. ## Re: How many atoms are there in 11.0g or CO2?
Convert 11.0 g of $CO_2$ into moles by finding the molar mass of $CO_2$. Then multiply by Avogadro's constant.
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# If two bodies one light and other heavy have equal kinetic energies, which one has a greater momentum
1. Heavy body
2. Light body
3. Both have equal momentum
4. It depends on the actual velocities
5. None of the above
Option 1 : Heavy body
## Detailed Solution
Concept:
The energy associated with a body when it is moving is known as Kinetic Energy. It is given by:
$$KE=\frac{1}{2}mV^2$$
The momentum of anybody is the product of mass and velocity i.e.
P = m × V
where m = mass of the body and V = Velocity of body.
Calculation:
Given:
The kinetic energy of both bodies is the same.
Let the mass of heavier body be m1 kg and the mass of lighter body be m2 kg.
(KE)1 = (KE)2
$$\begin{array}{l} \frac{1}{2}{m_1}V_1^2 = \frac{1}{2}{m^2}V_2^2\\ \frac{{{V_2}}}{{{V_1}}} = \sqrt {\frac{{{m_1}}}{{{m_2}}}} \end{array}$$
For momentum ratio:
$$\frac{{{P_1}}}{{{P_2}}} = \frac{{{m_1}{V_1}}}{{{m_2}{V_2}}} = \sqrt {\frac{{{m_1}}}{{{m_2}}}}$$
m1 > m2, ∴ P1 > P2
i.e heavier body has greater momentum.
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Let $n$ be the number of contestants. Let $x_k$ be the number of contestants which solved exactly $k$ questions. Thus,
$x_0+x_1+x_2+x_3+x_4+x_5+x_6=n$
But nobody solved all six thus, $x_6=0$. Thus we have that,
$x_0+x_1+x_2+x_3+x_4+x_5=n$.
Now, I am trying to determine which one of x's has to be greater then $\frac{2}{5}n$, but I do not understand what you mean?
|
# 9.78 StringTable¶
This domain provides a table type in which the keys are known to be strings so special techniques can be used. Other than performance, the type StringTable(S) should behave exactly the same way as Table(String,S). See TableXmpPage for general information about tables.
This creates a new table whose keys are strings.
t: StringTable(Integer) := table()
table()
Type: StringTable Integer
The value associated with each string key is the number of characters in the string.
for s in split("My name is Ian Watt.",char " ")
repeat
t.s := #s
Void
for key in keys t repeat output [key, t.key]
["Ian",3]
["My",2]
["Watt.",5]
["name",4]
["is",2]
Void
|
# The Illustrated Self-Supervised Learning
I first got introduced to self-supervised learning in a talk by Yann Lecun, where he introduced the “cake analogy” to illustrate the importance of self-supervised learning. In the talk, he said:
“If intelligence is a cake, the bulk of the cake is self-supervised learning, the icing on the cake is supervised learning, and the cherry on the cake is reinforcement learning (RL).”
Though the analogy is debated, we have seen the impact of self-supervised learning in the Natural Language Processing field where recent developments (Word2Vec, Glove, ELMO, BERT) have embraced self-supervision and achieved state of the art results.
Curious to know the current state of self-supervised learning in the Computer Vision field, I read up on existing literature on self-supervised learning applied to computer vision through a recent survey paper by Jing et. al.
In this post, I will explain what is self-supervised learning and summarize the patterns of problem formulation being used in self-supervised learning with visualizations.
## Why Self-Supervised Learning?
To apply supervised learning with deep neural networks, we need enough labeled data. To acquire that, human annotators manually label data which is both a time consuming and expensive process. There are also fields such as the medical field where getting enough data is a challenge itself. Thus, a major bottleneck in current supervised learning paradigm is the label generation part.
## What is Self-Supervised Learning?
Self supervised learning is a method that poses the following question to formulate an unsupervised learning problem as a supervised one:
Can we design the task in such a way that we can generate virtually unlimited labels from our existing images and use that to learn the representations?
In self-supervised learning, we replace the human annotation block by creatively exploiting some property of data to set up a pseudo-supervised task. For example, here instead of labeling images as cat/dog, we could instead rotate them by 0/90/180/270 degrees and train a model to predict rotation. We can generate virtually unlimited training data from millions of images we have freely available on the internet.
Figure: End to End Workflow of Self-Supervised Learning
Once we learn representations from these millions of images, we can use transfer learning to fine-tune it on some supervised task like image classification of cats vs dogs with very few examples.
## Survey of Self-Supervised Learning Methods
Let’s now understand the various approaches researchers have proposed to exploit image and video properties and apply self-supervised learning for representation learning.
## 1. Image Colorization
Formulation:
What if we prepared pairs of (grayscale, colorized) images by applying grayscale to millions of images we have freely available?
We could use an encoder-decoder architecture based on a fully convolutional neural network and compute the L2 loss between the predicted and actual color images.
To solve this task, the model has to learn about different objects present in the image and related parts so that it can paint those parts in the same color. Thus, representations learned are useful for downstream tasks.
## 2. Image Superresolution
Formulation:
What if we prepared training pairs of (small, upscaled) images by downsampling millions of images we have freely available?
GAN based models such as SRGAN are popular for this task. A generator takes a low-resolution image and outputs a high-resolution image using a fully convolutional network. The actual and generated images are compared using both mean-squared-error and content loss to imitate human-like quality comparison. A binary-classification discriminator takes an image and classifies whether it’s an actual high-resolution image(1) or a fake generated superresolution image(0). This interplay between the two models leads to generator learning to produce images with fine details.
Both generator and discriminator learn semantic features that can be used for downstream tasks.
## 3. Image Inpainting
Formulation:
What if we prepared training pairs of (corrupted, fixed) images by randomly removing part of images?
Similar to superresolution, we can leverage a GAN-based architecture where the Generator can learn to reconstruct the image while discriminator separates real and generated images.
For downstream tasks, Pathak et al. have shown that semantic features learned by such a generator give 10.2% improvement over random initialization on the PASCAL VOC 2012 semantic segmentation challenge while giving <4% improvements over classification and object detection.
## 4. Cross-Channel Prediction
Formulation:
What if we predict one channel of the image from the other channel and combine them to reconstruct the original image?
Zhang et al. used this idea in their paper called “Split-Brain Autoencoder”. To understand the idea of the paper, let’s take an example of a color image of tomato.
Example adapted from “Split-Brain Autoencoder” paper
For this color image, we can split it into grayscale and color channels. Then, for the grayscale channel, we predict the color channel and for the color channel part, we predict the grayscale channel. The two predicted channels $X_1$ and $X_2$ are combined to get back a reconstruction of the original image. We can compare this reconstruction to the original color image to get a loss and improve the model.
This same setup can be applied for images with depth as well where we use the color channels and the depth channels from a RGB-HHA image to predict each other and compare output image and original image.
Example adapted from “Split-Brain Autoencoder” paper
## 1. Image Jigsaw Puzzle
Formulation:
What if we prepared training pairs of (shuffled, ordered) puzzles by randomly shuffling patches of images?
Even with only 9 patches, there can be 362880 possible puzzles. To overcome this, only a subset of possible permutations is used such as 64 permutations with the highest hamming distance.
Suppose we use a permutation that changes the image as shown below. Let’s use the permutation number 64 from our total available 64 permutations.
Now, to recover back the original patches, Noroozi et al. proposed a neural network called context-free network (CFN) as shown below. Here, the individual patches are passed through the same siamese convolutional layers that have shared weights. Then, the features are combined in a fully-connected layer. In the output, the model has to predict which permutation was used from the 64 possible classes. If we know the permutation, we can solve the puzzle.
To solve the Jigsaw puzzle, the model needs to learn to identify how parts are assembled in an object, relative positions of different parts of objects and shape of objects. Thus, the representations are useful for downstream tasks in classification and detection.
## 2. Context Prediction
Formulation:
What if we prepared training pairs of (image-patch, neighbor) by randomly taking an image patch and one of its neighbors around it from large, unlabeled image collection?
To solve this pre-text task, Doersch et al. used an architecture similar to that of a jigsaw puzzle. We pass the patches through two siamese ConvNets to extract features, concatenate the features and do a classification over 8 classes denoting the 8 possible neighbor positions.
## 3. Geometric Transformation Recognition
Formulation:
What if we prepared training pairs of (rotated-image, rotation-angle) by randomly rotating images by (0, 90, 180, 270) from large, unlabeled image collection?
To solve this pre-text task, Gidaris et al. propose an architecture where a rotated image is passed through a ConvNet and the network has to classify it into 4 classes(0/90/270/360 degrees).
Though a very simple idea, the model has to understand location, types and pose of objects in an image to solve this task and as such, the representations learned are useful for downstream tasks.
## 1. Image Clustering
Formulation:
What if we prepared training pairs of (image, cluster-number) by performing clustering on large, unlabeled image collection?
To solve this pre-text task, Caron et al. propose an architecture called deep clustering. Here, the images are first clustered and the clusters are used as classes. The task of the ConvNet is to predict the cluster label for an input image.
Papers:
## 2. Synthetic Imagery
Formulation:
What if we prepared training pairs of (image, properties) by generating synthetic images using game engines and adapting it to real images?
To solve this pre-text task, Ren et al. propose an architecture where weight-shared ConvNets are trained on both synthetic and real images and then a discriminator learns to classify whether ConvNet features fed to it is of a synthetic image or a real image. Due to adversarial nature, the shared representations between real and synthetic images get better.
## 1. Frame Order Verification
Formulation:
What if we prepared training pairs of (video frames, correct/incorrect order) by shuffling frames from videos of objects in motion?
To solve this pre-text task, Misra et al. propose an architecture where video frames are passed through weight-shared ConvNets and the model has to figure out whether the frames are in the correct order or not. In doing so, the model learns not just spatial features but also takes into account temporal features.
Papers:
## Citation Info (BibTex)
If you found this blog post useful, please consider citing it as:
@misc{chaudhary2020selfsupervised,
title = {The Illustrated Self-Supervised Learning},
author = {Amit Chaudhary},
year = 2020,
note = {\url{https://amitness.com/2020/02/illustrated-self-supervised-learning}}
}
Categories:
Updated:
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But in practice people use both words the same way. Math course with grade of 80 and weight of 30%. To calculate percentages, start by writing the number you want to turn into a percentage over the total value so you end up with a fraction. Weighted average grade calculator. In our example, 0.8077 x 100 = 80.77. You calculate your overall GPA by averaging the scores of all your classes. The national board Central Board of Secondary Education uses a percentage system coupled with a positional grade that indicates the student's performance with respect to his/her peers. SGPA To Percentage Conversion Calculator: Feel free to make use of this online SGPA to percentage calculator to convert SGPA into a percentage in a simple way within fractions of seconds. So let's try to actually do this division right over here. Lessons > > > Projects > > Additional Resources; Parent Page; About the Authors; Discount & Sales Tax. If we are calculating the Grades for a case where less the number means a higher Grade, than we need to use â<â instead of â>â as the operator. If we have a percentage instead of numbers, then we also need to define % in the logical function. Percentage Calculator Percentage Difference Percentage Points Decimals, Fractions and Percentages Introduction to Fractions Introduction to Decimals Percents Index. A GPA below 3.0 is considered to be poor, while a GPA between 3.0 and 3.5 would be considered below average. Quickgrade | the easiest free grade ⦠Ratios, rates, & percentages ... Well, let me just do the division and convert to a decimal, which is very easy to convert to a percentage. Multiply this decimal by 100 to get the average percentage. Long time math fans may remember our first foray into the world of percentages way back in the 12th and 13th episodes of the podcast. Weighted grade calculation. So, 615 divided by 900 is equal to 0.68. Grade calculator. Things to remember about Excel Formula for Grade. Percentage simply means 'out of 100', so 72% is '72 out of 100' and 4% is '4 out of 100', etc. 9% means 9 out of every 100, or $$\frac{9}{100}$$. Calculating percentages in Excel is easy. The symbol '%' means 'per cent'. How to calculate percentages can be easier than you may realize. Percent (or per cent) means one hundredth. The Indian Certificate of Secondary Education board doesn't and gives only the mark obtained. This example shows a Cambridge International A Level student who has achieved Grade A*. Depending on your teacherâs grading scale, 80.77% would be a B or a B-. Biology course with grade of 90 and weight of 50%. MANILA, Philippines â A limited to a small percentage of grade 5 Filipino children excelled in mathematics, reading and writing, according to the results of a 2019 study conducted by the Southeast Colleges report GPA (grade point average) on a 4.0 scale. High school gpa calculator. Final grade calculator â rogerhub. DU Admission Eligibility Criteria â Grade to Percentage Conversion Formula After many trials and rejections, DU has finally prepared a formula to take out the percentage from the CGPA. High school gpa calculator. Therefore, 1% means 1/100 or one hundredth, and 7% means 7/100 or seven hundredths. Percentages: Home; Introduction. Change the last box Grade D- ⥠value So we're going to literally divide 4 by 16. Improve your math knowledge with free questions in "Compare percents to fractions and decimals" and thousands of other math skills. Before you can calculate a percentage, you [â¦] The Grade Scale tab found in BYU Grades is the scale that will be used to determine studentsâ final grades in the course. Learn the basics of the concept of percent in this easy lesson! For simple fractions with denominators that are easily multiplied to reach 100, the process of finding an equivalent fraction is an easy path to converting a fraction to percentage. Example. The Percentage System is defined with a maximum grade of 100 marks, a minimum grade of 0 marks and a passing grade from 30 to 40 marks, depending on the university; lower percentages may be considered passing grades at several universities. Available both as a ⦠Percentages: Home; Introduction. Practice: Percent word problems. This means your test grade is 80.77%. Lessons > > > Projects > > Additional Resources; Parent Page; About the Authors; Powered by Create your own unique website with customizable templates. Driver video universal download free 3 months interest penalty calculator Ms 20 manual Download os 9330 Patch photoshop cs2 Gpa calculator good calculators. Powered by Create your own unique website with customizable templates. Explore various other math calculators as well as hundreds of calculators addressing finance, health, fitness and more. How to calculate weighted average (formula and examples). This free percentage calculator computes a number of values involving percentages, including the percentage difference between two given values. For example, assume that the test was really difficult and you'd like to change the scale so that getting 50% is already a passing grade (usually it's 60% or even 65%). In the US, you need a minimum GPA of 2.75 to pass. Excel magic trick 1055: grading: calculate current percentage. Less obvious divisors may require fall back to dividing the numerator by the denominator to get a decimal result, and shifting the decimal place to get the corresponding percentage. KS3 Maths Percentages learning resources for adults, children, parents and teachers. This website uses cookies to improve your experience, analyze traffic and display ads. Grade calculator. Then, turn the fraction into a decimal by dividing the top number by the bottom number. Tip: you can adjust your overall grade to calculate the corresponding final grade in real time. Advertisement. Statement of Results Because of this, the grade that appears in BYU Grades may differ from the final grade you receive. The top grade is an A, which equals 4.0. Ben eggleston â grade calculator. Note: Instructors may add to or change grade calculations throughout the year, especially when submitting final grades. The illustration below shows how Grade A* and percentage uniform marks will be reported on the statement of results from June 2010, where applicable. Finally, multiply the decimal by 100 to find the percentage. This is the standard scale at most colleges, and many high schools use it. The answer will be your grade as a percentage (your score out of 100). So 10 percent of 50 apples is 5 apples: the 5 apples is the percentage. Weighted average grade calculator. Calculating percentages can be an easy task. Just enter your marks and press the button! Example: Find the percentage equivalent for a student who has secured the semester grade point average of 8 . Grade point for 61 percentage in India is 3.5 and Grade is First Class, whereas in United States grade point is 1.00 and Grade is D This percentage to GPA calculator can be used to find your equivalent GPA of your percentage in all countries. There are numerous percentage calculators online that can help with task by simply searching for âpercentage calculator.â However, there may be a time when (however, unlikely it sounds) you may need to be able to calculate percentages without any digital assistance. An online exam marks percentage calculator to calculate the percentage of mark scored in exams. So, 0.68 times 100 equals 68, or 68%. Percentage scale - in that set of boxes, you can change the grading scale from the default one. Since percentages are just hundredth parts (which means they are FRACTIONS), we can very easily write them as fractions and as decimals. Test grade calculator. Score calculator for teachers. Grade calculator. 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## Abstract
Linker histones are essential for DNA compaction in chromatin. They bind to nucleosomes in a 1:1 ratio forming chromatosomes. Alternative configurations have been proposed in which the globular domain of the linker histone H5 (gH5) is positioned either on- or off-dyad between the nucleosomal and linker DNAs. However, the dynamic pathways of chromatosome assembly remain elusive. Here, we studied the conformational plasticity of gH5 in unbound and off-dyad nucleosome-bound forms with classical and accelerated molecular dynamics simulations. We find that the unbound gH5 converts between open and closed conformations, preferring the closed form. However, the open gH5 contributes to a more rigid chromatosome and restricts the motion of the nearby linker DNA through hydrophobic interactions with thymidines. Moreover, the closed gH5 opens and reorients in accelerated simulations of the chromatosome. Brownian dynamics simulations of chromatosome assembly, accounting for a range of amplitudes of nucleosome opening and different nucleosome DNA sequences, support the existence of both on- and off-dyad binding modes of gH5 and reveal alternative, sequence and conformation-dependent chromatosome configurations. Taken together, these findings suggest that the conformational dynamics of linker histones and nucleosomes facilitate alternative chromatosome configurations through an interplay between induced fit and conformational selection.
## INTRODUCTION
In eukaryotic cells, DNA packs tightly into the nuclei by forming higher-order chromatin structures. In chromatin, DNA wraps around histone core proteins to form complexes called nucleosomes, which interact with each other and are connected by segments of linker DNA (L-DNA) (1–3). One of the proteins determining the conformation, compaction and dynamics of chromatin is the linker histone (LH). LH proteins bind to the nucleosome in a 1:1 ratio at a site located between the L-DNAs, forming a chromatosome (4,5).
The H1/H5 family of LH proteins contributes not only to the dynamic compaction of chromatin but also participates in the regulation of processes such as replication and transcription (6–8). The existence of two proposed structures of the 30 nm chromatin fiber, the interdigitated solenoid (9) and the two-start zig-zag helix (10), implies that the L-DNA connecting successive nucleosomes varies not only in length (11) but also in conformation. However, how LH proteins interact with the nucleosome and the L-DNA, and how they affect the conformation and dynamics of the L-DNA, is not yet sufficiently understood (12–16).
LH proteins are composed of a short flexible N-terminal tail (∼20 amino acid residues), a globular domain (∼80 amino acid residues) and a long disordered basic C-terminal tail (∼100 amino acid residues). Whereas the C-terminal tail appears to affect both the affinity and geometry of the LH-nucleosome interaction (17–20), and may undergo DNA-mediated folding (21), it appears that the N-terminal tail only affects the binding affinity and specificity (18,22). Interestingly, although the C-terminal tail determines the organization of higher-order chromatin structures (17,23) and the binding geometry of the linker DNA (17,18) it does not appear to affect the LH positioning around the dyad (17). Moreover, the full length LH and the isolated globular domain protect the same L-DNA from micrococcal nuclease digestion (24), indicating that the globular domain determines the binding geometry, whereas the C-terminal tail further refines the interaction with the linker DNA. H5 is an avian LH that differs in sequence from mammalian LH isoforms, but shares most similarity with human H1.0, which is mostly found in terminally differentiated cells (see sequence alignment in Supplementary Data). The unbound gH5 adopts a winged helix fold consisting of three α-helices in which the helix-turn-helix motif is followed by a β-hairpin (pdb ID: 1 hst, 2.5 Å resolution) (25). The closed (gH5B) and open (gH5A) conformations of gH5 revealed by the two subunits (B and A) in the asymmetric unit of this crystal structure differ in the structure of the β-hairpin and its orientation with respect to the third α-helix. In gH5B, the β-hairpin bends toward the third α-helix forming hydrophobic contacts with the helix (Figure 1A), whereas in gH5A, it is extended (Figure 1B). Interestingly, the β-hairpin sequence is highly conserved among human LH isoforms, suggesting that it may play an important functional role (Supplementary Data).
Figure 1.
Conformational flexibility of the free gH5. (A) Closed conformation gH5B. (B) Open conformation gH5A. On the left, the two conformations (chains B and A in pdb ID 1hst) are shown in A and B, respectively. Proteins are shown in cartoon representation and colored according to secondary structure: α helices in orange, β sheets in green and unstructured regions in gray. This coloring is used throughout the manuscript. The conformational space of gH5 is described by the angles ϕ1 and ϕ2 (see Materials and Methods). The following vectors are shown: vH along the axis of helix α3, vB threading through the β sheet; vBH connecting the centers of vH and vB; vBT connecting the center of vB with the β turn; vHT connecting the center of vH with the β turn. ϕ1 is the angle between vH and vHT; ϕ2 is the angle between vBH and vBT. For clarity, vH and vB are shown in red and longer than their actual definition marked with black thin lines. All other vectors are shown in blue and their endpoints as black spheres. On the right, two-dimensional histograms of the sampling of the ϕ12 conformational space for the corresponding gH5 conformation during CMD and AMD simulations (Table 1) are shown. The red and blue crosses mark the ϕ1 and ϕ2 values in the crystal structure for gH5B and gH5A, respectively. See also Supplementary Figures S1 and S2.
Figure 1.
Conformational flexibility of the free gH5. (A) Closed conformation gH5B. (B) Open conformation gH5A. On the left, the two conformations (chains B and A in pdb ID 1hst) are shown in A and B, respectively. Proteins are shown in cartoon representation and colored according to secondary structure: α helices in orange, β sheets in green and unstructured regions in gray. This coloring is used throughout the manuscript. The conformational space of gH5 is described by the angles ϕ1 and ϕ2 (see Materials and Methods). The following vectors are shown: vH along the axis of helix α3, vB threading through the β sheet; vBH connecting the centers of vH and vB; vBT connecting the center of vB with the β turn; vHT connecting the center of vH with the β turn. ϕ1 is the angle between vH and vHT; ϕ2 is the angle between vBH and vBT. For clarity, vH and vB are shown in red and longer than their actual definition marked with black thin lines. All other vectors are shown in blue and their endpoints as black spheres. On the right, two-dimensional histograms of the sampling of the ϕ12 conformational space for the corresponding gH5 conformation during CMD and AMD simulations (Table 1) are shown. The red and blue crosses mark the ϕ1 and ϕ2 values in the crystal structure for gH5B and gH5A, respectively. See also Supplementary Figures S1 and S2.
From experimental and computational studies, a range of different models for the chromatosome structure have been proposed (11,17,26–37,38). In most of these, the nucleosome was modeled either without any L-DNA, or with different lengths of static or coarse-grained L-DNAs. L-DNA fluctuations up to ±45° were measured in a recent 1 μs MD simulation of the nucleosome (39). Because of the highly dynamic nature of DNA in chromatin (40) it is likely that the binding of LH is influenced by the local chromatin conformation. To address the role of nucleosome dynamics and to obtain a unified model of LH-nucleosome interactions, we previously carried out computational docking of the globular domain of H5 in the closed conformation (gH5B) to the nucleosome (32). We accounted for the flexibility of two flanking 10 base pairs long L-DNAs by applying normal mode analysis (NMA) to generate a range of conformations. Then, with Brownian dynamics (BD) based docking, we generated structures of gH5B-nucleosome encounter complexes. For a wide range of nucleosomal conformations with the L-DNA ends less than 65 Å apart, we identified a single dominant binding mode, in which gH5B binds between the nucleosomal DNA (N-DNA) and one of the L-DNAs, asymmetrically with respect to the nucleosomal dyad axis in an off-dyad configuration (Figure 2A).
Figure 2.
Chromatosome configurations. (A) The off-dyad configuration proposed from BD docking by Pachov et al. (32). (B) The on-dyad configuration revealed in the crystal structure of Zhou et al. (36). The images on the right show the nucleosome aligned with the dyad axis pointing towards the viewer and were obtained by 2 rotations, first vertical and second horizontal, marked by the 2 curved arrows. The insets show schematic representations of the gH5-nucleosome binding configurations. The numbers represent the DNA grooves as follows: 0 = the minor groove at the dyad, −1,+1 = the neighboring major grooves of N-DNA toward L-DNA1 and L-DNA2, respectively, −2,+2 = the major grooves of L-DNA1 and L-DNA2, respectively, at the junction with N-DNA, −3,+3 = the following minor grooves of L-DNA1 and L-DNA2, respectively. Helix α3 is shown as an arrow oriented from the N- to the C-terminus, whereas the turn β1 is shown as a curved line representing the closed conformation.
Figure 2.
Chromatosome configurations. (A) The off-dyad configuration proposed from BD docking by Pachov et al. (32). (B) The on-dyad configuration revealed in the crystal structure of Zhou et al. (36). The images on the right show the nucleosome aligned with the dyad axis pointing towards the viewer and were obtained by 2 rotations, first vertical and second horizontal, marked by the 2 curved arrows. The insets show schematic representations of the gH5-nucleosome binding configurations. The numbers represent the DNA grooves as follows: 0 = the minor groove at the dyad, −1,+1 = the neighboring major grooves of N-DNA toward L-DNA1 and L-DNA2, respectively, −2,+2 = the major grooves of L-DNA1 and L-DNA2, respectively, at the junction with N-DNA, −3,+3 = the following minor grooves of L-DNA1 and L-DNA2, respectively. Helix α3 is shown as an arrow oriented from the N- to the C-terminus, whereas the turn β1 is shown as a curved line representing the closed conformation.
Asymmetric binding models of the LH have since been derived from NMR and site-directed mutagenesis studies of gH1 (35), and by cryo-electron microscopy of a 12 nucleosome-containing chromatin fiber with H1 bound (33). Although similar to the binding mode we proposed for gH5, these models differ in the details of the interaction, suggesting that the LH sequence may also contribute to the chromatosome configuration. Recently, Zhou et al. determined a crystal structure of the gH5 bound to the nucleosome (36). Interestingly, they showed that gH5 interacts with the nucleosome dyad and both L-DNAs in an on-dyad configuration (Figure 2B). In addition, based on their previous structural study on the gH1-nucleosome complex (35), they proposed that the binding mode of LH proteins depends on their sequence, with gH5 binding on-dyad and gH1 binding off-dyad. Further, they suggested that the two LH proteins contribute to different packing of chromatin fibers, with gH5 promoting tighter structures because of its on-dyad binding mode. Notably, the nucleosome sequence used in this study was different from that which we used in our original docking simulations. This raises the question whether the DNA sequence may play a role in establishing a specific chromatosome configuration. Earlier, Cui et al. revealed that binding of the LH to the nucleosome is stabilized by interactions with AT-rich DNA, and suggested the presence of sequence-specific hydrophobic interactions (28). However, these interactions could not be confirmed either by our first models for the gH5-nucleosome encounter complex or by the recent crystal structure (32,36). Therefore, a full understanding of how the sequences and the conformational dynamics of the LH and the nucleosome affect the chromatosome configuration, and ultimately, the chromatin structure, remains elusive.
Here, we employed classical molecular dynamics (CMD) and accelerated molecular dynamics (AMD) simulations to study the conformational plasticity of the nucleosome and of gH5 in free and off-dyad nucleosome-bound forms. In addition, we investigated the dynamic pathways of chromatosome assembly with BD simulations. We provide evidence that the chromatosome configuration and assembly pathways depend on conformational dynamics and are determined by an interplay between induced fit and conformational selection mechanisms. Importantly, in addition to the off-dyad configuration, by using BD simulations we were able to reconstitute the on-dyad configuration revealed in the latest crystal structure. Thus, we demonstrate that both the on- and off-dyad binding modes of gH5 are plausible. Our findings provide fundamental insights into chromatosome structure, dynamics and assembly pathways.
## METHODS
### Selection of starting structures
The structures of the closed and open conformations of gH5 were obtained from chains B (Figure 1A) and A (Figure 1B) of the crystal structure (pdb ID 1hst, 2.5 Å resolution) (25), respectively. The nucleosome core particle (NUC) was taken from the crystal structure (pdb ID 1kx5, 1.9 Å resolution) (41). The histone tails were removed and 10 base pairs of L-DNA were added to each end (see Pachov et al. (32) for details). Hydrogen atoms were added at pH 7 by using the tleap module of the AMBER software (42). The structure of the NUC-gH5B encounter complex with the dominant binding mode of gH5B as described by Pachov et al. (32) was taken as the starting configuration for the molecular dynamics simulations of the chromatosome. The initial superposition of the crystal structure of gH5A on the starting configuration of the NUC-gH5B chromatosome revealed significant steric clashes between gH5A and the L-DNA. To minimize the clashes, snapshots from an initial 20 ns of the CMD simulation of gH5A taken every 400 ps were superimposed by minimizing the root mean square deviation (RMSD) of the gH5 non-hydrogen atoms from the NUC-gH5B configuration. Next, two of the superimposed snapshots (corresponding to the structures at 2.4 and 11.2 ns of the gH5A simulation) were substituted instead of gH5B in the NUC-gH5B structure. We refer to the resulting two models as NUC-gH5A and NUC-gH5A*, respectively. We used both in the simulations to exclude potential bias due to the initial modeled configuration of the gH5A-nucleosome complex.
### Classical molecular dynamics simulations
The unbound structures of gH5B and gH5A, consisting of 74 residues, were neutralized with 11 Cl ions and solvated in a truncated octahedral box of explicit TIP3P (43) water molecules containing an additional ∼50 mM NaCl with a minimal distance between any solute and solvent atoms of 12 Å. The two systems had 24 345 and 22 134 atoms, respectively. The three models of the chromatosome (NUC-gH5B, NUC-gH5A and NUC-gH5A*) were neutralized with 226 Na+ ions and were solvated in a truncated octahedral box containing an additional ∼50 mM NaCl. For this, 50 Na+ and 50 Cl ions were first added, followed by the TIP3P water molecules. The total Na+ ion concentration was ∼200 mM. Only monovalent ions were added and the salt concentration was kept below physiological to avoid any potential artifacts due to inaccuracies in the force field parameters for ions (44,45). The minimal distance between the solute, including the neutralizing Na+ ions, and solvent atoms was 4 Å. Each chromatosome system had 198 303 atoms. In addition, a system with the free nucleosome having 197 127 atoms was setup by removing gH5B and 11 Cl ions from the solvated NUC-gH5B system.
We used the all-atom AMBER force field (46) modified for DNA (‘ff99’) (47) and proteins (‘ff99SB’) (48)) with further corrections for the DNA backbone (‘parmbsc0’) (49). Recent progress in force field development has corrected some of the limitations of these force fields (50–52). Based on previous evaluations (53,54), we estimate that the properties analyzed in this study are not affected by the known limitations of the force field versions we used. For ions, we used the Joung–Cheatham parameters optimized for TIP3P water (55). All systems were optimized by energy minimization with the AMBER software and equilibrated in NAMD (see Supplementary Methods) (56). Then, two independent CMD simulations were performed with a standard protocol (Table 1) (see Supplementary Methods).
#### Performed molecular dynamics simulations
Table 1.
Performed molecular dynamics simulations
Simulation Parameters gH5B gH5A NUC NUC-gH5B NUC-gH5A NUC-gH5A*
CMD-01 Time (ns) 600 600 100 324 324 324
VDIHED (kcal/mol) 749.1 ± 10.9 750.7 ± 10.9 16 095.7 ± 53.2 16 828.5 ± 52.7 16 844.2 ± 51.7 16 847.0 ± 53.2
CMD-02 Time (ns) 600 600 324 105 100 100
VDIHED (kcal/mol) 748.3 ± 11.2 749.9 ± 11.3 16 075.7 ± 50.5 16 844.6 ± 53.4 16 847.7 ± 55.4 16 853.7 ± 53.1
AMD-01 Time (ns) 200 208 108 100 100
α 44.4 44.4 850.5 850.5 850.5
EDIHED (kcal/mol) 976.8 976.8 21 097.0 21 101.2 21 101.2
ΔVDIHED (kcal/mol) 8.5 ± 3.8 8.6 ± 3.8 113.2 ± 7.4 114.0 ± 7.8 114.4 ± 7.8
AMD-02 Time (ns) 200 212 114 112 112
α 51.8 51.8 850.5 850.5 850.5
EDIHED (kcal/mol) 1005.7 1013.8 22 798.0 22 802.2 22 802.2
ΔVDIHED (kcal/mol) 11.5 ± 4.5 12.3 ± 4.7 193.6 ± 10.6 192.0 ± 10.9 192.4 ± 10.9
AMD-03 Time (ns) 200 208 108 112 112
α 59.2 59.2 850.5 850.5 850.5
EDIHED (kcal/mol) 1050.8 1050.8 24 499.0 24 503.2 24 503.2
ΔVDIHED (kcal/mol) 15.9 ± 5.4 16.2 ± 5.5 281.5 ± 14.4 281.8 ± 14.1 281.9 ± 14.3
AMD-04 Time (ns) 200 200
α 51.8 51.8
EDIHED (kcal/mol) 1109.3 1117.4
ΔVDIHED (kcal/mol) 18.4 ± 6.2 19.5 ± 6.4
AMD-05 Time (ns) 200 200
α 51.8 51.8
EDIHED (kcal/mol) 1212.9 1221.0
ΔVDIHED (kcal/mol) 26.9 ± 8.1 27.2 ± 8.1
Simulation Parameters gH5B gH5A NUC NUC-gH5B NUC-gH5A NUC-gH5A*
CMD-01 Time (ns) 600 600 100 324 324 324
VDIHED (kcal/mol) 749.1 ± 10.9 750.7 ± 10.9 16 095.7 ± 53.2 16 828.5 ± 52.7 16 844.2 ± 51.7 16 847.0 ± 53.2
CMD-02 Time (ns) 600 600 324 105 100 100
VDIHED (kcal/mol) 748.3 ± 11.2 749.9 ± 11.3 16 075.7 ± 50.5 16 844.6 ± 53.4 16 847.7 ± 55.4 16 853.7 ± 53.1
AMD-01 Time (ns) 200 208 108 100 100
α 44.4 44.4 850.5 850.5 850.5
EDIHED (kcal/mol) 976.8 976.8 21 097.0 21 101.2 21 101.2
ΔVDIHED (kcal/mol) 8.5 ± 3.8 8.6 ± 3.8 113.2 ± 7.4 114.0 ± 7.8 114.4 ± 7.8
AMD-02 Time (ns) 200 212 114 112 112
α 51.8 51.8 850.5 850.5 850.5
EDIHED (kcal/mol) 1005.7 1013.8 22 798.0 22 802.2 22 802.2
ΔVDIHED (kcal/mol) 11.5 ± 4.5 12.3 ± 4.7 193.6 ± 10.6 192.0 ± 10.9 192.4 ± 10.9
AMD-03 Time (ns) 200 208 108 112 112
α 59.2 59.2 850.5 850.5 850.5
EDIHED (kcal/mol) 1050.8 1050.8 24 499.0 24 503.2 24 503.2
ΔVDIHED (kcal/mol) 15.9 ± 5.4 16.2 ± 5.5 281.5 ± 14.4 281.8 ± 14.1 281.9 ± 14.3
AMD-04 Time (ns) 200 200
α 51.8 51.8
EDIHED (kcal/mol) 1109.3 1117.4
ΔVDIHED (kcal/mol) 18.4 ± 6.2 19.5 ± 6.4
AMD-05 Time (ns) 200 200
α 51.8 51.8
EDIHED (kcal/mol) 1212.9 1221.0
ΔVDIHED (kcal/mol) 26.9 ± 8.1 27.2 ± 8.1
### Accelerated molecular dynamics simulations
In AMD simulations (57), a positive boost potential is added to the system when the intrinsic potential energy is lower than a reference energy. In this way, the energy barriers for exploring different regions of the conformational space are lowered. The method has been shown to accurately describe biomolecular dynamics on time scales significantly shorter than those required by CMD (58). We applied a variant of the method in which only the dihedral potentials are boosted (57,59). The modified potential $${\rm{V}}_{{\rm{DIHED}}}^{\rm{M}}$$is:
\begin{equation*}{\rm{V}}_{{\rm{DIHED}}}^{\rm{M}} = \left\{ {\begin{array}{*{20}{c}} {{{\rm{V}}_{{\rm{DIHED}}}}{\rm{\ if\ }}{{\rm{V}}_{{\rm{DIHED}}}} \ge {{\rm{E}}_{{\rm{DIHED}}}}}\\ {{{\rm{V}}_{{\rm{DIHED}}}}{\rm{ + \Delta }}{{\rm{V}}_{{\rm{DIHED\ }}}}{\rm{if\ }}{{\rm{V}}_{{\rm{DIHED}}}} < {{\rm{E}}_{{\rm{DIHED}}}}} \end{array}} \right\}\end{equation*}
where $${{\rm{V}}_{{\rm{DIHED}}}}$$= the intrinsic dihedral potential, $${{\rm{E}}_{{\rm{DIHED}}}}$$= the reference potential, $${\rm{\Delta }}{{\rm{V}}_{{\rm{DIHED}}}}$$= the boost potential.
\begin{equation*}{\rm{\Delta }}{{\rm{V}}_{{\rm{DIHED}}}} = \frac{{{{\left( {{{\rm{E}}_{{\rm{DIHED}}}} - {{\rm{V}}_{{\rm{DIHED}}}}} \right)}^{\rm{2}}}}}{{{\rm{\alpha + }}\left( {{{\rm{E}}_{{\rm{DIHED}}}} - {{\rm{V}}_{{\rm{DIHED}}}}} \right)}},\end{equation*}
where α = the acceleration factor.
Accelerated simulations for the gH5B, gH5A, NUC-gH5B, NUC-gH5A and NUC-gH5A* were started after 100 ns of CMD simulation. The parameters used and the length of the simulations are shown in Table 1. Here, α = 1/5 · (3.5 · NR), where 3.5 is the recommended energy contribution per residue and NR is the number of residues. EDIHED = VDIHED + 3.5 · NR, where VDIHED is the average torsion potential after 100 ns CMD simulation. All parameters from the CMD simulations (Supplementary Methods) were kept.
### Analysis of structural dynamics
To describe the conformational plasticity of gH5, we first defined two vectors vH and vB that thread through the two structural elements involved, the helix α3 and the sheet β1, respectively (Figure 1): (i) vH connects the geometric centers of the second and third turns of the gH5 helix α3, defined by the backbone atoms (C, N, O, CA) of residues 67–71 and 71–75, respectively; (ii) vB connects the geometric center of the backbone atoms of residues 82 and 94 with the geometric center of the backbone atoms of residues 83 and 93. In addition, we defined the center of the turn between the two β strands as the geometric center of the backbone atoms of residues 87–91. The vectors vHT and vBT connect this point with the centers of vectors vH and vB, respectively. The latter two are connected by the vector vBH. Finally, we defined two angles ϕ1 and ϕ2 as follows (Figure 1): ϕ1 is the angle between vectors vH and vHT, ϕ2 is the angle between the vectors vBH and vBT.
To characterize the structural dynamics within the chromatosome (Figures 3–6), we setup a reference xyz coordinate system based on two vectors vN1 and vN2 (Figure 3A). vN1 connects the geometric centers of nucleotides 45–48, 287–290, 123–126, 209–212 and nucleotides 83–86, 249–252 whereas vN2 connects the geometric centers of nucleotides 100–103, 232–235, 24–27, 311–314 and nucleotides 144–147, 188–191, 66–69, 266–269. vN1 was defined along the dyad axis and crosses vN2, approximately in the center of the nucleosome. The origin of the xyz coordinate system was defined at the point where vN1 crosses the nucleosomal DNA at the geometric center of nucleotides 83–86, 249–252. Then, the x-axis was defined to extend along vN1, the y-axis was defined along the cross product of x and vN2, and the z-axis was defined along the cross product of x and y. The orientation of gH5 with respect to the N-DNA was described by the angles θ1 and θ2 (Figure 3B), where θ1 = the angle between the xy projection of vH and the x axis and θ2 = the angle between the yz projection of vH and the z-axis. The motions of the L-DNAs were described using the angles γ1 and γ2 (Figure 6A and B), where γ1 = the angle between the xz projection of the vector vL1 or vL2 and the z-axis, and γ2 = the angle between the xy projection of vL1 or vL2 and the y axis. vL1 and vL2 were defined based on selected DNA residues along the helical axis of the two L-DNAs. vL1 connects the geometric centers of nucleotides 12–15, 320–323 and 2–5, 330–333, whereas vL2 connects the geometric centers of nucleotides 153–156, 179–182 and 163–166, 169–172 (Figure 6A). The numbering of the DNA nucleotides starts from 1 and 168 at the 5′ ends of L-DNA1 and L-DNA2, respectively, and runs to 167 and 334 at the 3′ ends of L-DNA2 and L-DNA1, respectively. All non-hydrogen atoms were used to define the nucleotides. All vector-based angle calculations were performed in VMD (60).
Figure 3.
Orientation and dynamics of gH5 in the chromatosome. (A) Structure of the off-dyad chromatosome. A reference coordinate system, xyz, was constructed using the vectors vN1 and vN2. These were defined between selected DNA bases such as to cross as closely as possible to the center of the nucleosome (see Materials and Methods). vN1 points along the dyad axis. vN2 connects two points on opposite sides of the nucleosome DNA, above and below the dyad point, respectively. To construct the coordinate system, vN1 was translated on the x-axis, the y-axis was defined along the cross product of x and vN2, and the z-axis was defined along the cross product of x and y. The two linker DNAs (L-DNA1 and L-DNA2), nucleosomal DNA (N-DNA), gH5 and the vector vH (see Figure 1) are labeled. (B) Schematic representation of the definition of the two angles, θ1 and θ2, describing the orientation of helix α3 of gH5 with respect to N-DNA. θ1 is the angle between the xy projection of vH and the x axis. θ2 is the angle between the yz projection of vH and the z axis. (C and D) Orientation and dynamics of gH5B (C) and gH5A (D). The number of contacts of three structural regions of gH5 (turn β1, loop l1 and helix α3) with different DNA regions (N-DNA and L-DNA1) and the histograms of θ1 and θ2 distributions are plotted. See also Supplementary Figure S3.
Figure 3.
Orientation and dynamics of gH5 in the chromatosome. (A) Structure of the off-dyad chromatosome. A reference coordinate system, xyz, was constructed using the vectors vN1 and vN2. These were defined between selected DNA bases such as to cross as closely as possible to the center of the nucleosome (see Materials and Methods). vN1 points along the dyad axis. vN2 connects two points on opposite sides of the nucleosome DNA, above and below the dyad point, respectively. To construct the coordinate system, vN1 was translated on the x-axis, the y-axis was defined along the cross product of x and vN2, and the z-axis was defined along the cross product of x and y. The two linker DNAs (L-DNA1 and L-DNA2), nucleosomal DNA (N-DNA), gH5 and the vector vH (see Figure 1) are labeled. (B) Schematic representation of the definition of the two angles, θ1 and θ2, describing the orientation of helix α3 of gH5 with respect to N-DNA. θ1 is the angle between the xy projection of vH and the x axis. θ2 is the angle between the yz projection of vH and the z axis. (C and D) Orientation and dynamics of gH5B (C) and gH5A (D). The number of contacts of three structural regions of gH5 (turn β1, loop l1 and helix α3) with different DNA regions (N-DNA and L-DNA1) and the histograms of θ1 and θ2 distributions are plotted. See also Supplementary Figure S3.
To analyze the slow motions of the L-DNAs, we calculated the essential dynamics of the nucleosome core particle from principal component analysis (PCA) of the CMD simulations with the CPPTRAJ program (61). For this, we first removed gH5 and superimposed all non-hydrogen atoms of the nucleosome core particle. Secondly, we calculated the covariance matrix and diagonalized it to extract the first 25 eigenvectors and their eigenvalues. Then, we projected the trajectory onto the 25 calculated modes, and extracted the minimum and maximum projection values for each mode. Finally, we used these values to generate individual trajectories along each mode and analyze the motions of the L-DNAs in the trajectories of the first two modes that contributed most to the overall dynamics.
### Brownian dynamics simulations
Both gH5A and gH5B were docked using rigid body BD based docking simulations to eight nucleosome structures with different L-DNA1 conformations and L-DNA2 fixed in a specific, highly-populated conformation. These were selected from the CMD simulation without LH based on the γ1 and γ2 angles (Figure 7C and D). In addition, we docked gH5B in the nucleosome structure taken from the recent chromatosome structure by Zhou et al. (pdb ID 4qlc, 3.5 Å resolution) (36) using the protocol of Pachov et al. (32). In short, NMA was applied using the NOMAD-Ref web-server (62) to generate nucleosome conformations with different degrees of L-DNA opening. The original structure (conformation 0), as well as two conformations with RMSD of 1 and 2 Å, respectively (all non-hydrogen atoms superimposed) along the first mode (‘conformation 1’ and ‘conformation 2’), were selected. The RMSD of the L-DNAs in these two structures from the original structure was 4.7 and 9.2 Å (the non-hydrogen atoms of the core histones superimposed), respectively.
First, polar hydrogen atoms were added to the structures by using PDB2PQR 1.8 (63) and partial atomic charges and atomic radii were assigned from the AMBER99 force field. The electrostatic potential was calculated for all structures by solving the non-linear Poisson–Boltzmann equation on a grid with a 1 Å spacing and dimension of 1933 in APBS 1.4 (64) at temperature 298.15 K. The solvent and solute dielectric constants were 78.54 and 2, respectively and the ionic strength was 100 mM. Higher solute dielectric constants of 4, 6 and 8 were also tested for docking gH5 to the highly populated conformation of the nucleosome from snapshot 5 (Figure 7C and D). The results were insensitive to varying the solute dielectric constant in this range. To define dielectric boundary conditions, the van der Waals surface was used.
The BD simulations were performed with SDA7 (Simulation of Diffusional Association) (65) using electrostatic interaction forces. Short-range interactions were neglected, and a 0.5 Å excluded volume criterion to prevent overlap was applied. Effective charges were assigned to charged residues on the protein and to P atoms on the DNA using the ECM program (66). The trajectories were started randomly on a sphere at a center-to-center distance of b = 280 Å and stopped at a center-to-center distance of c = 500 Å. The time step was set to 1 ps for center-to-center distances up to 160 Å and increased linearly up to 100 ps at a distance of 260 Å. A total of 20 000 trajectories were generated for each pair of LH-nucleosome conformations simulated. The diffusional encounter complex was considered formed when the following two geometric conditions were satisfied: (i) the center-to-center distance of gH5 and the nucleosome <73 Å, and (ii) the nucleosome dyad point and gH5 separation <40 Å. The interaction energies and the coordinates of a complex were recorded if the RMSD to previously recorded complexes was >1 Å and the interaction energy was within the 5000 lowest (most favorable) energy complexes recorded. A complex with RMSD < 1 Å to a previously recorded complex but lower energy was recorded as a substitute of that complex. The 5000 recorded complexes were clustered into 10 groups according to the backbone RMSD values between them. Upon ranking the clusters by their population during the BD simulations, representative structures of the clusters were generated.
## RESULTS AND DISCUSSION
### The linker histone displays conformational plasticity
To describe the conformational plasticity of gH5 during the simulations (Table 1), we defined the Φ1 and Φ2 angles (Figure 1A and B, see Materials and Methods for details) using vectors with a small angular variance due to intrinsic internal motions (see Supplementary Methods and Figure S1A). In the crystal structure of gH5, the angles in the gH5B conformation are Φ1 = 103.62° and Φ2 = 53.06° whereas for the gH5A conformation, they are Φ1 = 95.00° and Φ2 = 91.73° (Figure 1).
In the CMD simulations, gH5B opened partially to a transient conformation characterized by an increase of Φ2 to about 70°–80° and a decrease of Φ1 (Figure 1A, Supplementary Figure S1B and C). In AMD simulations, gH5B opened to either partially or fully open conformations (Figure 1A, Supplementary Figure S1C). At the lowest boost (AMD-01), gH5B remained in the closed conformation for most of the time but opened irreversibly after ∼165 ns. Interestingly, at intermediate boosts (AMD-02, AMD-03), mainly reversible transitions between the closed and partially open conformations occurred, whereas at high boosts (AMD-04, AMD-05), we observed reversible (on the 200 ns timescale of the AMD simulations) transitions to fully open conformations. On the other hand, the open form, gH5A, adopted conformations characterized by Φ2 values greater than 120° in CMD simulations (Figure 1B, Supplementary Figure S1B and C). These differed from that observed in the crystal structure with turn β1 packing on the opposite side of the β sheet. Interestingly, in one CMD simulation gH5A closed irreversibly adopting a conformation similar to gH5B (Figure 1B). In AMD simulations, gH5A closed partially at the lowest boost (AMD-01) and adopted short lived fully closed conformations at intermediate to high boosts (AMD-02, AMD-03, AMD-04, AMD-05). In conclusion, on the timescale of the simulations, we observed both reversible and irreversible transitions between the different conformations of gH5 for both starting structures and we identified a partially closed conformation characterized by a defined range of Φ2 values (65°–80°). Furthermore, we found that the open conformation is an ensemble of conformations spanning a wide range of Φ2 values. Based on these findings, we propose that the unbound gH5 has a measurable preference for the closed conformation. The closed form is characterized by hydrophobic interactions between residues in turn β1 (V87, A89) and residues in the helix α3 as well as hydrogen bonds between polar sidechains (R47 in the helix α2, Q83 in the sheet β1) and the backbone of turn β1 (see Supplementary Methods and Figure S2). Of these residues, only A89 is conserved in H5 and human H1 LH proteins (Supplementary Data) suggesting that the LH sequence may influence the equilibrium between the two conformations. As residues in the turn β1 have been proposed to be important for nucleosome binding (26,35), it is possible that the changes in the equilibrium between the 2 conformations may result in different LH-nucleosome binding geometries.
### The open linker histone conformation forms a more rigid chromatosome structure
To characterize the binding mode of gH5 to the nucleosome, we adopted a schematic representation for which we aligned the nucleosome with the dyad axis perpendicular to the view plane and L-DNA1 and L-DNA2 on the left and right side, respectively (Figure 2). We then numbered the DNA grooves as follows: 0 = the minor groove at the dyad, −1,+1 = the neighboring major grooves of N-DNA toward L-DNA1 and L-DNA2, respectively, −2,+2 = the major grooves of L-DNA1 and L-DNA2 at the junction with N-DNA, −3,+3 = the following minor grooves of L-DNA1 and L-DNA2, respectively (Figure 2). In the off-dyad binding mode, the LH helix α3 binds in the major groove −1, the turn β1 interacts with groove −1 and −2, and the loop l1 interacts with groove −2 (Figure 2A). In the on-dyad binding mode, helix α3 binds in the minor groove −3, turn β1 in groove 0, and the loop l1 interacts with the groove 0 (Figure 2B).
To study the orientation and dynamics of the off-dyad bound gH5 in the simulations of the chromatosome, we monitored the number of contacts formed between different secondary structure elements of gH5 and the DNA. In addition, we defined the θ1 and θ2 angles (Figure 3A and B) to describe the rocking and tumbling motions, respectively, of helix α3 in the major groove of the N-DNA (see Materials and Methods). For this, a reference coordinate system was defined using the vectors vN1 and vN2. vN1 was defined along the dyad axis and vN2 in a direction approximately orthogonal to the dyad axis. Neither of these vectors was sensitive to the intrinsic internal fluctuations (Supplementary Figure S3A). From CMD simulations, we found that the pattern of contacts between gH5 and the nucleosome depends on the gH5 conformation. The closed gH5B formed more contacts between its loop l1 and L-DNA1 and fewer contacts between its turn β1 and L-DNA1 compared to the open gH5A (Figure 3C, D and Supplementary Figure S3B). Remarkably, the ranges of sampled θ1 and θ2 angles was greater in the CMD simulations of the NUC-gH5B chromatosome compared to the NUC-gH5A form (Figure 3C, D and Supplementary Figure S3B) indicating that the open form, gH5A, contributes to a more rigid chromatosome. This suggests that the open gH5A is the preferred conformation of gH5 in the off-dyad configuration of the chromatosome. The gH5A-nucleosome off-dyad binding geometry is in agreement with previous experiments that revealed residues involved in H1.0-nucleosome binding (26). H1.0 is the mammalian LH isoform most similar to H5 (Supplementary Data). Interestingly, an off-dyad configuration has also been obtained for the Drosophila H1 globular domain (35) but with a different orientation of the LH in which helix α3 does not dock in the major groove of N-DNA, suggesting that the detailed geometry of the off-dyad configuration may be LH-isoform dependent.
### The closed linker histone conformation opens in accelerated chromatosome simulations
To characterize the conformational dynamics of the LH while bound to the nucleosome, we monitored the Φ1 and Φ2 angles (Figure 1) during MD simulations of the chromatosome (Figure 4A, B and Supplementary Figure S4). In the CMD simulations of the NUC-gH5B, gH5B remained closed with a slight increase of both Φ1 and Φ2 (Figure 4A). In AMD simulations of NUC-gH5B, three open states were observed for gH5 in which both Φ1 and Φ2 angles increased by up to 40°. When the boost was low (AMD-01), we observed reversible transitions between closed and open conformations between 45 and 60 ns (Supplementary Figure S4). In the simulations with higher boosts (AMD-02, AMD-03), Φ2 increased irreversibly up to 120° (Figure 4A, Supplementary Figure S4). Interestingly, opening of gH5B was correlated with an increase in Φ1 (Figure 4A) in contrast to the simulations of the free gH5 (Figure 1). In the NUC-gH5A simulations, gH5A adopted a predominant open conformation with Φ2 larger than 105° and Φ1 smaller than 110° (Figure 4B, Supplementary Figure S4). The values of Φ2 were similar to those observed in CMD simulations of free gH5A (Figure 1) and reflect the packing of the turn β1 away from helix α3. Therefore, the extended structure of the β-turn observed in the crystal structure is not stable during the simulations. Importantly, gH5A did not close in any of the simulations of the chromatosome. These findings suggests that the closed conformation of gH5 is not stable in the fully bound complex with the nucleosome in the off-dyad configuration and provide further support for an induced fit mechanism, in which gH5B forms the encounter complex and opens in the fully bound complex.
Figure 4.
Conformational dynamics of gH5 in the chromatosome. (A) NUC-gH5B; (B) NUC-gH5A. The two-dimensional histograms for the sampling of the Φ12 conformational space during the four CMD and AMD simulations (Table 1) are shown. The graphs are colored as in Figure 1. See also Supplementary Figure S4.
Figure 4.
Conformational dynamics of gH5 in the chromatosome. (A) NUC-gH5B; (B) NUC-gH5A. The two-dimensional histograms for the sampling of the Φ12 conformational space during the four CMD and AMD simulations (Table 1) are shown. The graphs are colored as in Figure 1. See also Supplementary Figure S4.
### The open linker histone conformation interacts with thymidines in the linker DNA
To explore how the open gH5A conformation stabilizes the chromatosome, we analyzed the hydrophobic contacts between turn β1 of gH5 and thymidines in L-DNA1. We observed that residues V87 and A89 from gH5A form alternative networks of hydrophobic interactions with 1 to 3 thymidine bases in L-DNA1 (Figure 5A, Supplementary Figure S5). Although these interactions require a higher thymidine content in the L-DNA, the precise position of the bases may vary. Thus, the hydrophobic interactions are only partially DNA sequence specific. In CMD simulations of the NUC-gH5B complex, no hydrophobic contacts between gH5B and L-DNA1 were formed, whereas in the AMD simulations between 7 and 16% of the frames showed at least one such contact (Figure 5B, Supplementary Figure S5A). The formation of 1 or 2 hydrophobic contacts between 40 and 55 ns with low boost (AMD-01), and after ∼50 ns with higher boost (AMD-02, AMD-03) was correlated with the opening of the gH5B (Supplementary Figure S5B). In contrast, in over 60% of the trajectories of the NUC-gH5A complex (∼100% in the simulations with the highest boost), at least one such hydrophobic contact was formed (Figure 5B, Supplementary Figure S5C and D). Interestingly, the sampling efficiency of the hydrophobic contacts was greater in the AMD simulations in particular, for the NUC-gH5A* system (Supplementary Figure S5D). These findings indicate that the increased stability of the chromatosome with gH5 in the open conformation is due to additional hydrophobic contacts formed between gH5A (V87, A89) and thymidines in L-DNA1. These findings could explain the proposed higher preference of the LH for T-rich regions of DNA (28).
Figure 5.
Hydrophobic contacts between gH5 and L-DNA1 in the chromatosome. (A) Representative structures from the AMD-01 simulation of the NUC-gH5A chromatosome showing different hydrophobic contacts between V87 and A89 of gH5 and thymidine bases in L-DNA1. Protein residues are shown in cyan, whereas the thymidine bases are shown in yellow with the methyl group in red. (B) Percentages of MD trajectory frames in which at least one hydrophobic contact is established for NUC-gH5B (red) and NUC-gH5A (blue) chromatosomes. See also Supplementary Figure S5.
Figure 5.
Hydrophobic contacts between gH5 and L-DNA1 in the chromatosome. (A) Representative structures from the AMD-01 simulation of the NUC-gH5A chromatosome showing different hydrophobic contacts between V87 and A89 of gH5 and thymidine bases in L-DNA1. Protein residues are shown in cyan, whereas the thymidine bases are shown in yellow with the methyl group in red. (B) Percentages of MD trajectory frames in which at least one hydrophobic contact is established for NUC-gH5B (red) and NUC-gH5A (blue) chromatosomes. See also Supplementary Figure S5.
### Binding of the linker histone to the nucleosome remodels the linker DNA dynamics
To study how the binding of the LH influences the dynamics of the L-DNAs, we first defined the γ1 and γ2 angles which describe the motions of the L-DNAs in the xz and xy planes of the reference coordinate system respectively (Figure 6A, B and see Materials and Methods for details). Then, we calculated the essential dynamics from PCA of the CMD simulations and monitored the γ1 and γ2 angles in the trajectory projections along the first two modes.
Figure 6.
Effect of gH5 binding to the nucleosome on L-DNA motions. (A) Structure of the chromatosome showing vectors and angles defining the motions of the L-DNAs. The reference coordinate system xyz is shown in Figure 3. The vectors vL1 and vL2 were defined based on selected DNA bases to represent the helical axes of L-DNA1 and L-DNA2, respectively. The double headed arrows show the directionality of the L-DNA motions described by the two angles, γ1 and γ2 (see Materials and Methods for details). (B) Schematic representation of the definition of γ1 and γ2. γ1 is the angle between the xz projection of vL1 or vL2 and the z-axis, whereas γ2 is the angle between the xy projection of vL1 or vL2 and the y axis. (C) Motions of the L-DNAs (L-DNA1 in red and L-DNA2 in blue) along the first two essential dynamics modes of the CMD-trajectory. The data from the simulations of the nucleosome (NUC) and the chromatosome (NUC-gH5B and NUC-gH5A) are shown in the first, second and third columns, respectively. See also Supplementary Figure S6.
Figure 6.
Effect of gH5 binding to the nucleosome on L-DNA motions. (A) Structure of the chromatosome showing vectors and angles defining the motions of the L-DNAs. The reference coordinate system xyz is shown in Figure 3. The vectors vL1 and vL2 were defined based on selected DNA bases to represent the helical axes of L-DNA1 and L-DNA2, respectively. The double headed arrows show the directionality of the L-DNA motions described by the two angles, γ1 and γ2 (see Materials and Methods for details). (B) Schematic representation of the definition of γ1 and γ2. γ1 is the angle between the xz projection of vL1 or vL2 and the z-axis, whereas γ2 is the angle between the xy projection of vL1 or vL2 and the y axis. (C) Motions of the L-DNAs (L-DNA1 in red and L-DNA2 in blue) along the first two essential dynamics modes of the CMD-trajectory. The data from the simulations of the nucleosome (NUC) and the chromatosome (NUC-gH5B and NUC-gH5A) are shown in the first, second and third columns, respectively. See also Supplementary Figure S6.
In the CMD simulation of the free nucleosome, L-DNA1 moved predominantly along a path that is a combination of the two types of motions described by the two angles (Figure 6C, Supplementary Figure S6A). On the other hand, L-DNA2 moved predominantly in the xy plane along mode 1 showing little to no variation of γ1, whereas its motion along mode 2 differed in the 2 independent CMD simulations (Figure 6C, Supplementary Figure S6A).
In CMD simulations of the chromatosome, a clear separation between the xy and xz motions along different modes was not observed (Figure 6D, E and Supplementary Figure S6). Both L-DNAs sampled predominantly a combined path along all modes, suggesting that the presence of the LH alters the relative timescales of these motions. Interestingly, the closed gH5B conformation only marginally reduced the amplitude of the L-DNA motions (Figure 6D, Supplementary Figure S6B). In contrast, the open gH5A conformation suppressed greatly the L-DNA1 motion (Figure 6E, Supplementary Figure S6C, D and E). These findings are in agreement with the observation that gH5A showed less flexibility in its orientation when bound to the nucleosome compared to gH5B (Figure 3), providing further support for the induced fit mechanism described in previous paragraphs. The selective suppression of L-DNA1 in the fully bound gH5-nucleosome complex in the off-dyad configuration, has important implications for the assembly of higher-order chromatin structures (3) and it is analogous to the proposed change in DNA dynamics upon core histone protein binding in the nucleosome (67). Interestingly, our L-DNAs are asymmetric in sequence, L-DNA2 having a higher GC content, and we observed asymmetric dynamics of the L-DNAs (Figure 6A, Supplementary Figure S6A). These findings are in agreement with a recent study showing L-DNA sequence dependent, asymmetric flexibility and unwrapping of the nucleosome (68).
### Nucleosome dynamics determine the binding mode of the linker histone conformations
To explore the effect of the conformational dynamics on the chromatosome assembly, we performed BD simulations with different gH5 and nucleosome conformations. For this, we first calculated the electrostatic potential of gH5 and found that it differs between the two conformations. The large positive stripe on gH5A is perturbed on gH5B leading to a more evenly distributed potential (Figure 7A and B), suggesting that the gH5-nucleosome encounter complex may differ between gH5A and gH5B.
Figure 7.
Preparation of BD simulations. (A and B) Molecular electrostatic potentials of gH5B (A) and gH5A (B). (C and D) Snapshots from the CMD-01 simulation of the free nucleosome selected for BD simulations (labeled in red) on the γ12 histograms for L-DNA1 (C) and L-DNA2 (D). See also Supplementary Figure S7.
Figure 7.
Preparation of BD simulations. (A and B) Molecular electrostatic potentials of gH5B (A) and gH5A (B). (C and D) Snapshots from the CMD-01 simulation of the free nucleosome selected for BD simulations (labeled in red) on the γ12 histograms for L-DNA1 (C) and L-DNA2 (D). See also Supplementary Figure S7.
Then, we selected eight representative snapshots from the CMD simulation of the free nucleosome based on the distribution of the γ1 and γ2 angles. An increase of γ1 and a decrease of γ2 reflect the opening of L-DNA1 along the two types of motion described by the two angles (Figure 6A and B). Because in the off-dyad configuration, gH5 binds only to L-DNA1, we varied the conformation of L-DNA1 (Figure 7C), keeping the conformation of L-DNA2 fixed (Figure 7D). Our selection of snapshots was not affected by the limited sampling of the L-DNA dynamics in the 100 ns CMD simulation (Supplementary Figure S7A and B). With this selection, we cover the representative conformational space sampled by L-DNA1 in the absence of the LH. To evaluate the binding modes resulting from the BD simulations, we used the scheme described in Figure 2. In addition, we show the orientation of helix α3 with an arrow pointing from its N- to the C-terminus.
The closed gH5B conformation formed an off-dyad encounter complex with nucleosome conformations from snapshots 2, 3, 5 and 8 (Table 2). As snapshot 5 lies in the center of the γ12 histogram, this finding indicates that the off-dyad configuration is the predominant binding mode for gH5B. Moreover, it shows that closing of L-DNA1 along one direction (lower values of γ1) and the opening along the other (lower values of γ2) (snapshots 2 and 3), as well as opening of L-DNA1 along both directions simultaneously (snapshot 8), still permits binding of gH5B in this configuration. These findings confirm our previous observations based on NMA and BD simulations (32). The open gH5A conformation formed similar off-dyad encounter complexes in snapshots 3, 6 and 7 (Table 2). This indicates that opening of the L-DNA1 in either direction (higher γ1 or lower γ2), but not in both simultaneously, is required for the binding of gH5A in this configuration. The BD simulations also reveal other conformation-dependent configurations of the gH5-nucleosome encounter complex but not the on-dyad configuration (Table 2, Supplementary Figure S7C and D). Taken together, these findings indicate that besides the LH conformation, the nucleosome conformational dynamics determine the LH binding configuration. Therefore, we propose that the off-dyad encounter complex forms through a conformational selection mechanism in which different conformations of the LH bind to a subset of specific conformations of the nucleosome. Interestingly, the structure of a chromatin fiber (33) revealed different degrees of L-DNA opening in different regions with asymmetric binding of LH H1. This further suggests that the interplay between LH binding and L-DNA dynamics is important for the higher-order chromatin structures.
#### Binding configurations of gH5-nucleosome encounter complexes#
Table 2.
Binding configurations of gH5-nucleosome encounter complexes#
### Chromatosome assembly simulations reveal experimentally-determined configurations
Up to this point, we have focused on the off-dyad chromatosome configuration which we originally proposed based on BD simulations (32). Interestingly, the recent crystal structure of the chromatosome revealed the closed gH5B conformation bound in an on-dyad configuration contacting both L-DNA arms (Figure 2B) (36). Therefore, there is an apparent contradiction between the experimental and simulation-based configurations. However, it should be noted that the sequence of the nucleosome in the crystal structure differs from that used in our BD simulations (32). To test whether the DNA sequence may influence the chromatosome configuration, we applied our original protocol based on NMA and BD simulations to dock gH5B to the nucleosome taken from the new structure. With the very closed nucleosome conformation from the crystal structure, we could not reproduce the reference bound complex (Table 3). However, this is not surprising because it is unlikely that a diffusional encounter complex is formed with a tightly closed conformation of the nucleosome. Remarkably, when we docked gH5B to a nucleosome structure opened slightly along the lowest frequency mode obtained from NMA (see Methods), we obtained the on-dyad configuration in the two topmost ranking clusters (Table 3). Besides showing that BD simulations accurately describe chromatosome configurations, these findings suggest that the LH binding mode to the nucleosome may depend on DNA sequence as well as histone sequence. Therefore, we propose that both the off-dyad and on-dyad configurations are possible upon binding of gH5 to different nucleosomes with different nucleic acid sequences. A higher GC content around the dyad combined with a higher AT content in the L-DNA may favor the off-dyad configuration in which arginines from the third helix of gH5 form direct contacts with bases in the major groove of nucleosomal DNA (Supplementary Figure S8). Our proposal that a single LH isoform is able to bind to nucleosomes in different configurations depending on the sequence and conformation is supported by evidence for both on- and off-dyad binding modes for both gH1 (17,19,33,35) and gH5 (32,36).
#### Binding configurations of encounter complexes#
Table 3.
Binding configurations of encounter complexes#
### Concluding remarks
In this work, a series of classical and accelerated MD and BD simulations was performed to explore the dynamic nature of LH - nucleosome binding and chromatosome formation. In the MD simulations, we found that gH5 has the ability to switch from open to closed conformations and vice versa in solution. Interestingly, the free gH5 has a measurable preference for the closed form which is stabilized by a series of hydrophobic and hydrophilic interactions that involve residues from the turn β1. However, the open conformation stabilized the off-dyad encounter complex and significantly reduced the L-DNA motion through hydrophobic interactions with thymidines in the nearby L-DNA. This could explain the higher preference of the LH for T-rich regions (28), and provides further support for experimental observations (36). Moreover, the closed conformation opened in accelerated MD simulations of the chromatosome. Based on these findings, we propose an induced fit mechanism for the formation of the off-dyad chromatosome configuration. On the other hand, we show that the conformational plasticity of the nucleosome provides a framework for conformational selection during chromatosome assemby. Therefore, an interplay between induced fit and conformational selection mechanisms contribute to alternative chromatosome configurations which further affect the higher order chromatin structure. Finally, we show that when docking the closed gH5 conformation to the alternative DNA sequence used to solve the most recent crystal structure of the gH5-nucleosome complex, we observed the experimentally determined on-dyad binding mode of gH5. This opens up the possibility that, besides nucleosome and LH conformational plasticity, the DNA sequence may play a role in the chromatosome assembly without necessarily affecting the DNA binding affinity.
One potential limitation of our study may arise from not considering the highly flexible N- and C-terminal tails of the LH and the core histone proteins. It is notoriously challenging to sufficiently sample the conformational space of such highly flexible regions in molecular dynamics simulations. Especially the effect of the C-terminal tail of LH proteins may be of particular interest for future studies because, although it does not appear to affect the primary binding geometry around the dyad (17), it does affect the secondary positioning of LH proteins around the linker DNA (17–19) and the diversity of higher-order chromatin arrangements (17) through mechanisms that may involve DNA-mediated folding (20). The core histone H2A tails have been shown to affect the binding affinity of LH to the nucleosome (35). However, a recent long simulation of a free nucleosome (39) shows no significant overlap between the core histone H3 tails and the LH binding region, consistent with NMR data showing that the H3 tails are unaffected by binding of an H1 construct (35). This further suggests that the core histone tails may have little effect on the binding geometry of the LH whereas they may affect binding affinity through an induced fit mechanism in which the tails wrap around the LH after the initial binding. In conclusion, the chromatosome assembly pathways and final configurations may be significantly more complex than previously thought and further experimental and computational studies are necessary to elucidate them in the context of higher order chromatin structures.
## SUPPLEMENTARY DATA
Supplementary Data are available at NAR Online.
The authors thank Michael Martinez for helpful discussions and Alexey Shaytan and Anna Panchenko for providing their trajectory of the free nucleosome for analysis. V.C. is part of the Cells in Motion cluster of excellence of the University of Münster and thanks Hans Schöler for support.
## FUNDING
Klaus Tschira Foundation and the German Research Foundation [WA 1381/1-1 to R.C.W.]. Max Planck Society and the German Research Foundation [CO 975/1-1 to V.C.]. PRACE Research Infrastructure [computer resources for project LASIPROD to V.C.]. Funding for open access charge: HITS gGmBH.
Conflict of interest statement. None declared.
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# Let $V$ be a vector space over a field $F$ and let $B$ be a basis for $V$. In here $V$ can be infinite dimensional.
Let $V$ be a vector space over a field $F$ and let $B$ be a basis for $V$. In here $V$ can be infinite dimensional. Prove that every non zero vector $\mathbf{u} \in V$ can be expressed uniquely as a linear combination $$\mathbf{v} = c_1\mathbf{v_1}+c_2\mathbf{v_2}+...+c_m\mathbf{v_m}$$ for some $m \in \mathbb{N}$, some $c_1,c_2,...,c_m \in F$ and some $\mathbf{v_1,...v_m} \in B$ such that $c_i \neq 0$ for all $i$ and $\mathbf{v_i \neq v_j}$ whenever $i \neq j$.
Do note this question is absolutely not the same as the usual theorem we learned where if $B$ is a finite basis then all vectors are uniquely expressed by $B$. In this question, $B$ may not be finite, and furthermore, $\mathbf{v_1,...,v_m}$ are just some vectors in $B$ and may not be all the vectors in $B$.
I hope someone can verify my proof and let me know if there is any errors.
Since $V = \text{span}(B)$, every non zero vector $\mathbf{v} \in V$ can be expressed as a linear combination of vectors from $B$.
Assume a contradiction that $\mathbf{v}$ can be expressed in two ways.
$$\mathbf{v} = c_1\mathbf{v_1}+c_2\mathbf{v_2}+...+c_m\mathbf{v_m}$$ $$\mathbf{v} = d_1\mathbf{w_1}+d_2\mathbf{w_2}+...+d_n\mathbf{w_n}$$ where $m$ and $n$ may not be the same. But of course $\mathbf{w_1,w_2,...,w_n} \in B$. And do note our question said that $c_i \neq 0$, hence $d_i \neq 0$ as well.
Our first intuitive is to show that $m = n$, or else we cannot proceed. Here i present an error in my thinking at first in which i wrote show that $$(\mathbf{v_1,v_2,...,v_m}) = (\mathbf{w_1,w_2,...,w_n})$$ which is wrong as writing in this form suggest ordered vector and we are comparing $\mathbf{v_1}$ with $\mathbf{w_1}$, $\mathbf{v_2}$ with $\mathbf{w_2}$. But $\mathbf{v_1}$ can possibly be equals to $\mathbf{w_n}$ here. The correct way to write is as such: show that $$\{\mathbf{v_1,...,v_m}\} = \{\mathbf{w_1,...,w_n}\}$$ are the same set.
Take any $\mathbf{v_i} \in \{\mathbf{v_1,...,v_m}\}$, then assume a contradiction that $\mathbf{v_i} \not \in \{\mathbf{w_1,...,w_n}\}$. Then since $c_1\mathbf{v_1}+c_2\mathbf{v_2}+...+c_m\mathbf{v_m}- d_1\mathbf{w_1}-d_2\mathbf{w_2}-...-d_n\mathbf{w_n} = \mathbf{v-v} = 0$, we have $\mathbf{v_i} = \dfrac{1}{c_i}(d_1\mathbf{w_1}+...+d_n\mathbf{w_n}-c_1\mathbf{v_1}-...-c_{i-1}\mathbf{v_{i-1}}-c_{i+1}\mathbf{v_{i+1}}-...-c_m\mathbf{v_m}$, thus $$\mathbf{v_i} \in \text{span}(\{\mathbf{w_1,w_2,...,w_n,v_1,...v_{i-1},v_{i+1},...,v_m}\})$$
This is a contradiction as by the very definition of basis, the set $B$ is a linearly independent set and hence no element inside can be a linear combination of the other elements inside $B$. (side note: in this part of the proof, we only assumed no $\mathbf{v_i} \in \{\mathbf{w_1,...,w_n}\}$, but there can be such cases where $\mathbf{w_i} \in \{\mathbf{v_1,...v_{i-1},v_{i+1},...v_m}\}$ but it does not matter. Look at big picture that no element in $B$ can be expressed as LC as others.) Hence since it is a contradiction, then $$\mathbf{v_i} \in \{\mathbf{w_1,...,w_n}\}$$
WLOG, we can show that $$\mathbf{w_i} \in \{\mathbf{v_1,...,v_m}\}$$
Hence $$\{\mathbf{v_1,...,v_m}\} = \{\mathbf{w_1,...,w_n}\}$$ and again WLOG, we assume that $\mathbf{v_i} = \mathbf{w_i}$ for all $i$ and rewrite $$\mathbf{v} = c_1\mathbf{v_1}+c_2\mathbf{v_2}+...+c_m\mathbf{v_n}$$ $$\mathbf{v} = d_1\mathbf{v_1}+d_2\mathbf{v_2}+...+d_n\mathbf{v_n}$$
And the next part is very easy as $$(c_1-d_1)\mathbf{v_1}+(c_2-d_2)\mathbf{v_2}+...+(c_n-d_n)\mathbf{v_n} = \mathbf{v-v} = 0$$
and by linear independence $c_i - d_i = 0$ for all $i$ and thus $c_i = d_i$ for all $i$.
• The argumentation gets simpler if one augments the sum and writes $v=\sum_{i\in I}c_iv_i$ (where $B=\{v_i\}_{i\in I}$) and demands $c_i=0$ for all but finitely many $i$ ... – Hagen von Eitzen Oct 6 '17 at 17:26
• always wanted to do that but i feel safer when i write out the terms >.< – nan Oct 6 '17 at 17:28
• For me this ‘property’ is the definition of a basis. So whar definition do you use? – Bernard Oct 6 '17 at 17:40
• Let $V$ be a non zero vector space over a field $F$. A subset $B$ of $V$ is called a basis if the following two conditions are satisfied: i) $V$ is spanned by $B$. $$V =\text{Span}(B)$$ ii) $B$ is a linearly independent set in $V$. – nan Oct 6 '17 at 17:59
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# How do you solve and find the value of tan(sin^-1(1/2))?
Nov 26, 2016
$\tan \left({\sin}^{- 1} \left(\frac{1}{2}\right)\right) = \frac{1}{\sqrt{3}}$
#### Explanation:
Inverse trigonometric ratios are the inverse functions of the trigonometric functions. As an example, $y = \sin x$ means sine of $\angle x$ is $y$. As an inverse trigonometric ration this means that $\arcsin y = x$ or ${\sin}^{- 1} y = x$.
As $\sin \left(\frac{\pi}{6}\right) = \frac{1}{2}$, we have ${\sin}^{- 1} \left(\frac{1}{2}\right) = \frac{\pi}{6}$
and hence
$\tan \left({\sin}^{- 1} \left(\frac{1}{2}\right)\right) = \tan \left(\frac{\pi}{6}\right) = \frac{1}{\sqrt{3}}$
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# Is there a compact connected Hausdorff space in which every non-empty $G_\delta$ set has non-empty interior?
Q1. Is there a compact connected Hausdorff space (with at least two points) in which every non-empty $G_\delta$ set has non-empty interior? (Without the requirement for connectedness, every finite $T_1$ space is an example, and a more interesting example is the remainder of the Stone-Cech compactification of the integers, see this MSE question and also Parovicenko space.)
There are versions of the above question for LOTS (i.e. linearly ordered topological spaces with the order also called open-interval topology), and for topological groups.
Q2. Is there a compact connected LOTS in which every non-empty $G_\delta$ set has non-empty interior? (I believe the following is a restatement: Is there a compact connected LOTS which is not first-countable at any point?)
Q3. Is there a compact connected Hausdorff topological group in which every non-empty $G_\delta$ set has non-empty interior? (Such a group would necessarily have to be non-metrizable.)
Question 1 was inspired by the following MSE question (in particular by my answer there). Questions 2 and 3 are related and I feel the answers (to all questions) are probably known, in that case would you please provide reference(s).
Edit. Thanks to @ChristianRemling for pointing out that I am interested in examples with at least 2 points. (It follows that such examples, being connected and normal, will have at least continuum many points.)
Edit. The following answer was posted by @Alessandro Vignati (who perhaps could not post it is a comment): "You should have a look at the Stone-Cech reminder of $[0,1)$. I suspect this may be an example of what you're looking for in Q1".
First thank you for the suggested answer. While I agree that the Stone-Cech remainder of $[0,1)$ (or of $[0,\infty)$) is an example to look at, and I had already taken a (brief) look at related papers, I could not deduce the answer, so I posted the above question. Perhaps I am overlooking something obvious, but at any rate unless I see a more specific reference to the suggested result, or a (sketch of) proof, I would not consider the above question answered. Here are a couple of links to papers related to the Stone-Cech remainder $H^*$ of the half-line $H=[0,\infty)$ (indeed $H^*$ is compact and connected, and perhaps satisfies the condition about $G_\delta$ sets I am asking about, but I do not quite see this part, even if I agree it is not something unreasonable to suspect): http://arxiv.org/pdf/math/9805008.pdf and http://arxiv.org/pdf/0708.0838.pdf
• @JosephVanName Thank you ... I either didn't know or had forgotten this terminology, though I spent some time searching for $P$-spaces, but $P$-space is a too strong condition (I think when every $G_\delta$ set is itself open). – Mirko Apr 5 '15 at 19:15
• It was proved by Fine and Gillman that the remainder of a locally-compact realcompact space, e.g.[0,1), is an almost $P$-space. See N. Fine and L. Gillman, Extensions of continuous functions in $\beta\mathbb{N}$, Bull. Amer. Math. Soc. 66 (1960) 376–381. – Ramiro de la Vega Apr 6 '15 at 15:22
This is a proof of Alessandro Vignati's guess: Let $G_n$ be a decreasing sequence of nonempty open subsets of $X=\beta[0,1)\setminus[0,1)$. Choose $x\in\bigcap G_n$ - by assumption the intersection is nonempty. Then for each $n$ choose a pair of disjoint subsets of $\beta[0,1)$, namely $U_n\ni x$ and $V_n\supseteq X\setminus G_n$. They exist by normality of $\beta[0,1)$. Then we have $\bar U_n\cap X\subseteq G_n$. We may also assume that the sequence $U_n$ is decreasing. For every $n\in\mathbb{N}$ choose an open interval $I_n\subseteq [0,1)$ such that:
• $I_n\subseteq U_n$
• the supremum of $I_n$ is less than $1$
• the infimum of $I_n$ is more than $1-{1\over n}$
• to make things more elegant we may assume that $I_n$ sits above $I_{n-1}$
Such $I_n$ always exists since $U_n\cap X$ nonempty forces $U_n\cap[0,1)$ to be unbouded ($X$ has an empty interior in $\beta[0,1)$). Note that for $n<m$ we have $I_m\subseteq U_m\subseteq U_n$. Let $U=\bigcup I_n$ then for every $n$ there exists an $a<1$ such that $U\cap[a,1)\subseteq U_n$. Therefore $G=(\mathop{\rm int}\bar U)\cap X$ is contained in $\bigcap G_n$, and it is nonempty as $U$ is open and unbouded.
It's not hard to construct a compact connected LOTS with this property. Let $X_0$ be any countably saturated dense linear order, and let $X$ be its bounded Dedekind completion ("bounded" meaning also add points at $\pm\infty$). Explicitly, such an $X_0$ can be constructed by a transfinite induction of length $\omega_1$, where at each stage you add a new point into every cut (even cuts for which a sup or inf exists). Suppose $U_n$ is a sequence of open sets in $X$ and let $x\in\bigcap U_n$. Assume $x\neq\pm\infty$; if $x=\pm\infty$ the argument is similar. We can find a sequence of intervals $(a_n,b_n)\subseteq U_n$ with $a_n,b_n\in X_0$ and $$a_0<a_1<a_2<\dots<x<\dots<b_2<b_1<b_0.$$
Since $X_0$ is countably saturated, there exist $a,b\in X$ such that $a_n<a<b<b_n$ for all $n$. Thus $\bigcap U_n$ contains the $(a,b)$ and has nonempty interior (note that $x$ itself might not be in the interior; it could be $\sup a_n$ or $\inf b_n$, but it can't be both).
• I couldn't do the "but it can't be both" part on my own yesterday (using somewhat simpler but related ideas), thank you for being specific with the construction. I wasn't sure of the meaning of "countably saturated", wikipedia suggests there are two versions of the definition, I assume you meant the version with "countable sets of parameters" rather than "finite parameter sets". – Mirko Apr 5 '15 at 19:40
The completely regular spaces $X$ such that every $G_{\delta}$ set has a non-empty interior are called almost $P$-spaces. The following facts will help you construct numerous examples of almost $P$-spaces.
Recall that a $P$-space is a completely regular space where every $G_{\delta}$-set is open. Therefore, the notion of an almost $P$-space is a weakening of the notion of a $P$-space. If $X$ is locally compact and realcompact, then $\beta X\setminus X$ is an almost $P$-space (this fact generalizes the answer of Adam Przeździecki). A completely regular space $X$ is an almost $P$-space if and only if its Hewitt Realcompactification $\upsilon X$ is an almost $P$-space.
A product of spaces $X\times Y$ is an almost $P$-space if and only if both $X$ and $Y$ are almost $P$-spaces. It is easy to show that a dense subspace of an almost $P$-space is an almost $P$-space. However, a closed subspace of an almost $P$-space is not necessarily an almost $P$-space. In fact, every completely regular space can be embedded as a closed subspace of an almost $P$-space. If $B$ is a Boolean algebra, then the Stone space of $B$ is an almost $P$-space if and only if $B$ has no countable partitions. In particular, if $B$ is $\aleph_{1}$-saturated, then the Stone space $S(B)$ is an almost $P$-space. The papers 1,2 give more information on almost $P$-spaces (with the link to 2 provided by Mirko).
For question 2, an example of a totally ordered almost $P$-space is given in Proposition 2.3 of 2.
1. Almost P-spaces. Chang Il Kim. Commun. Korean Math. Soc. 18 (2003), No. 4, pp. 695–701
2. Ronnie Levy. Almost-P-Spaces. Can. J. Math., Vol. XXIX, No. 2, 1977, pp. 284-288
• Thank you, I also found another paper by Ronnie Levi about almost $P$-spaces – Mirko Apr 5 '15 at 20:33
• Mirko. Thanks for providing the link to that paper. – Joseph Van Name Apr 5 '15 at 20:47
• though I misspelled his name, should be Ronnie Levy. His definition is that in an almost P-space, $G_\delta$ sets have dense interiors (clearly he means dense in the $G_\delta$ set, and his version of the definition is equivalent to requiring that the interior be non-empty when the $G_\delta$ set is non-empty). – Mirko Apr 5 '15 at 20:54
I claim that no infinite compact group can be an almost $P$-space. In other words, in every compact group there is a nonempty $G_{\delta}$ that does not contain any nonempty open set.
Suppose that $G$ is an infinite compact group. Let $\mu$ be the Haar probability measure on $G$. I claim that every non-empty open subset of $G$ has positive measure. Suppose that $U\subseteq G$ is a non-empty open set. Then $G=\bigcup_{g\in G}Ug$, so by compactness, there are $g_{1},...,g_{n}$ with $G=Ug_{1}\cup... U g_{n}$. However, since $\mu(U)=\mu(Ug_{1})=...=\mu(Ug_{n})$, we conclude that $1=\mu(G)\leq\mu(Ug_{1})+...+\mu(Ug_{n})=n\mu(U)$, so $\mu(U)\geq\frac{1}{n}$. However, it is easy to construct a non-empty $G_{\delta}$ subset of $G$ with measure zero. Therefore $G$ is a non-empty $G_{\delta}$-set that does not contain any non-empty open set. A similar argument shows that every non-discrete locally compact abelian group is not an almost $P$-space.
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## anonymous 4 years ago fractions.find the sum or difference. simplify if possible. 15/20 - 9/20=
1. anonymous
Similar to $\frac{15-9}{20}$
2. moongazer
6/20 = 3/10
3. moongazer
just add the numerator and copy the denominator. cause it similar divide both sides by two to simplify.
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# three phase bridge rectifier
Discussion in 'General Electronics Chat' started by Michigan, Jul 1, 2013.
1. ### Michigan Thread Starter New Member
Jul 1, 2013
5
0
A three phase alternator with an external full wave bridge rectifier, the load bank maintains a voltage of 28V DC. What is the AC voltage value for the output of the alternator/ input to the rectifier at no load and at full load. The test results show 25.5V AC phase to phase at load, I was expecting 28V AC. Can someone provide a formula to calculate the AC voltage based on the given DC voltage.
2. ### donpetru Senior Member
Nov 14, 2008
190
27
For three phase bridge rectifier - on idle: Vdc = 1.41 * Vphase to phase.
3. ### cork_ie Active Member
Oct 8, 2011
385
66
Absolutely correct. You will have an additional approx 0.7 volt on each diode.
a total of approx 1.4 Volts
4. ### Michigan Thread Starter New Member
Jul 1, 2013
5
0
So basically according to cork_ie it will be 25.5V(phase-phase)+ 1.4V AC (voltage drop on each diode)= 26.9V DC(load voltage). Am I understanding it right it seems as were adding AC volts to get DC values.
donpetru formula is at idle so for my situation it would be V phase to phase= Vdc/1.41=28/1.41= 19.81 V so I would expect a lower voltage at ideal than at load, now this is not taking the diode voltage into account correct?
5. ### tbinder3 Member
Jun 30, 2013
30
1
DC is more of an average of AC, so ACpeak/max will be higher than DC.
At the load you will subtract the diodes voltage drop.
6. ### tbinder3 Member
Jun 30, 2013
30
1
Calculations:
**** im rippped here it goes
(Vmax X 2 X Y x freq X Rload X C) / (2 * Y x freq x Rload X C +1) = Vdc ('x' are multiplication)
where Y is 2 for a full-wave and 1 for a half-wave
But all you have to do is 1.41 multiplied by V
phase to phase
Last edited: Jul 2, 2013
7. ### t_n_k AAC Fanatic!
Mar 6, 2009
5,448
789
This collection of erroneous material is a concern.
Looking at a 3-phase full-wave bridge rectifier with diode drops neglected will give you a DC output of ...
$V_{\text{DC}}=\frac{3 \sqrt{2}}{\pi}V_{\text{rms}}=1.35V_{\text{rms}}$
Where Vrms is the rms line-to-line voltage for the 3-phase supply.
Last edited: Jul 3, 2013
8. ### tbinder3 Member
Jun 30, 2013
30
1
VRms = VDC with basic rectifiers
9. ### t_n_k AAC Fanatic!
Mar 6, 2009
5,448
789
I would suggest you think again.
Go back to the OP's particular question and do some research on 3-phase bridge rectifier analysis. You may be enlightened.
In your earlier post you quoted an equation involving several parameters such as load resistance, load capacitance & frequency - none of which were mentioned or relevant to the original question.
Then you wrote "But all you have to do is 1.41 multiplied by V
phase to phase".
You can't have it both ways when you now write "VRms = VDC with basic rectifiers"
aiemon likes this.
10. ### cork_ie Active Member
Oct 8, 2011
385
66
No I think you misunderstand me.
RMS (root mean square) voltage is the equivalent DC voltage that produces the same power dissipation in a resistive load.It is an average of voltage V's time. In inductive or capacitive loads things will be a little different.
For a pure sine wave, the RMS value is the square root of 2 divided by 2 (approx. 0.707) times the peak voltage.
Thus the peak voltage is 1/.707 = 1.414 times the RMS Voltage
In this case what you need to look at is Peak to Peak voltage which will be 1.414 times the RMS - but when passed through Positive and Negative rectifier diodes there is an approx 0.7V voltage drop in each diode. Therefore the output voltage will be theoretically Peak to Peak less 1.4 Volts. As it is a 3 phase rectifier you can consider it as 3 rectifiers in Parallel you will subtract the 1.4V once only and not three times.
I hope this clears the matter up for you
• ###### RMS.jpg
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11. ### cork_ie Active Member
Oct 8, 2011
385
66
Where is the ${\pi}$ coming from ? I think you may be confusing two different formulae $V_{\text{DC}}=\frac{3 \sqrt{3}}{\pi}V_{\text{}}$ (xxxxxxx) is probably what you are thinking of. i.e. formula used in a Fourier expansion which isn't really required here.
12. ### t_n_k AAC Fanatic!
Mar 6, 2009
5,448
789
If one considers the typical 3-phase bridge rectifier [see attachment], the rectified line-to-line voltage appears across the bridge output with conduction between the various phase-to-phase pairings occurring in identical 60° increments of the full 360° cycle.
The average DC output voltage can then readily be obtained by evaluating the averaged integration of the sine function over any 60° conduction cycle.
This may be shown mathematically using radian measure for instance as ...
$V_{\text{DC}}=\frac{1}{(\frac{\pi}{3})} \int_{\frac{\pi}{3}}^{\frac{2 \pi}{3}} V_m sin(\theta) d \theta=\frac{3}{\pi}V_m$-cos(\theta)$_{\frac{\pi}{3}}^{\frac{2 \pi}{3}} =\frac{3}{\pi}V_m=\frac{3 \sqrt{2}}{\pi}V_{\text{rms}}=1.35 V_{\text{rms}}$
Where Vm is the peak value of the rms line-to-line voltage Vrms
Note: The diode forward voltage drop is assumed to be zero in this analysis.
As you might see this isn't a Fourier expansion. In any event, I would think the Fourier expansion of the bridge output voltage waveform would have the DC or mean output value as the same as above. After all, doesn't the Fourier analysis allow one to find both the mean value and the harmonic content? The DC or mean value would be what a true DC measuring instrument would indicate when attached to the bridge output terminals.
• ###### 3 phase bridge rectifier.jpg
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Last edited: Jul 4, 2013
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13. ### Duane P Wetick Senior Member
Apr 23, 2009
415
20
For 25 VRMS, L-L or 14.4 VRMS L-N, the rectifier output will be 25/ 0.817 = 30.6 VDC... CURRENT I RMS = 0.817 x I DC...Alt. Power is 1.05 x DC Power.
These figures assume full converter with no commutation. These calculations take into account the (6) forward diode drops (Vf) of silicon ~0.6 Vdc.
Source of this information: Std. Handbook for Elec. Engrs. ISBN 007020974X
Many years designing power rectifiers have shown this information to be accurate.
Cheers, DPW [Everything has limitations...and I hate limitations.]
Last edited: Jul 5, 2013
14. ### LDC3 Active Member
Apr 27, 2013
920
161
How can you say 1.41 x Vrms = VDC + 1.4V? This is only true when Vrms = 1V.
15. ### t_n_k AAC Fanatic!
Mar 6, 2009
5,448
789
I had a look at Fink & Carrol - Standard Handbook for Elec. Eng. ISBN 07-020973-1. Is that the same ?
Table 12-2b therein summarizes various transformer fed single & poly-phase bridge rectifiers. Your comment that "For 25 VRMS, L-L or 20.4 V L-N, the rectifier output will be 25/ 0.817 = 30.6 VDC" doesn't square with handbook table. It states the DC output voltage for the 3-phase bridge topology is 2.34Es where Es is the bridge input line-to-neutral RMS voltage.
In any case, 25Vrms line-to-line isn't equivalent to 20.4Vrms line-to-neutral. 25Vrms line-to-line would be 14.43V rms line-to-neutral.
So according to the table
VDC=2.34*Es = 2.34*14.43 = 33.8V DC
or using the line-to-line voltage
VD=1.35*E_line-to-line = 1.35*25 = 33.8V DC
Were you including diode voltage drops as contributing to a likely practical outcome of 30.6V DC??
As a further comment: neglecting losses, the AC real input power and the DC load power would be the same. The transformer VA rating needs to be 1.05*DC load power owing to the effect of harmonics in the line currents.
I don't have a lot of confidence in the long departed OP's quoted numbers. I guess we'll never know.
Last edited: Jul 4, 2013
16. ### Michigan Thread Starter New Member
Jul 1, 2013
5
0
I appreciate all the responses, I remembered some things and picked up on your blog. The numbers still do not add up to me, I have an alternator output to the rectifier of 25.5 V L-L AC and a voltage output after the rectifier of 28 V DC under load. Even cosidering the diode losses I cant end up with a formul that can make both these known practical voltages add up. Do I have to take into consideration a ripple coefficent somehow?
17. ### Duane P Wetick Senior Member
Apr 23, 2009
415
20
Reduce the output loading and see what happens...or the AC voltage may be sagging under load...or one phase may be in-adequate or a loose connection may be suspect when currents are high.
Cheers, DPW [Everything has limitations...and I hate limitations.]
18. ### t_n_k AAC Fanatic!
Mar 6, 2009
5,448
789
It's possible that if one diode (for instance) is open circuit, that the measured DC output would fall to around 27 to 28V. Is your interest in this based on a suspicion that something may actually be faulty?
The only way to really check such matters is to look at the circuit waveforms using an oscilloscope.
Are you able to test the individual bridge input line currents to ascertain any significant imbalance between the three phases?
Last edited: Jul 9, 2013
19. ### Michigan Thread Starter New Member
Jul 1, 2013
5
0
Yes, my intrest in this is based on suspicion that something might be faulty and to understand how the values are what they are. The bridge currents are well balanced at 132.6, 133.6 & 134. AC voltage L-L are all 25.5-7 approxametly. There is more than one unit that has been tested and they all show similar results. I assme the formulas should give me a close approximte to real practical readings.
t n k, do not have an oscilloscope. Would a general check on the rectifier diodes with a multimeter be adequate with no voltage?
Duane, if the voltage is sagging under load it would be a quick drop then stabilizes correct?
20. ### t_n_k AAC Fanatic!
Mar 6, 2009
5,448
789
What you are testing is a reasonably big rectifier given those line currents. Since you seem to have the same result for more than one unit the indications are that this as good as you are going to get.
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# How to find Mean, variance, and standard deviation
## Population vs. sample
Before we dive into standard deviation and variance, it’s important for us to talk about populations and population samples. A population is the entire group of subjects that we’re interested in. A sample is just a sub-section of the population.
Hi! I'm krista.
So, as an example, if we’re interested in data about polar bears in the arctic, the population would be every single polar bear in that region. It would be very difficult, if not impossible, for us to ensure we’d looked at every polar bear. So we might choose instead to take a sample of the population, maybe only ???25??? bears, and use the data we collect about that smaller group in order to draw conclusions about the population as a whole.
If, on the other hand, we were interested in data about all the students in our math class, there might only be ???30??? other students, so it might be very reasonable for us to collect data about the entire population.
It’s important to know whether we’re talking about a population or a sample, because in this section we’ll be talking about variance and standard deviation, and we’ll use different formulas for variance and standard deviation depending on whether we’re using data from a population or data from a sample.
In all the formulas we use that involve a count of the number of subjects or participants, we’ll denote the number of subjects in a population as capital ???N???, and the number of subjects in a sample as lowercase ???n???.
## Formula for the mean
We learned previously that the formula for the mean of a population was
???\mu=\frac{\sum_{i=1}^n x_i}{n}???
Now that we’re a little more advanced and we want to start distinguishing between populations and samples, let’s update the mean formula and say that the mean of a population is
???\mu=\frac{\sum_{i=1}^N x_i}{N}???
The mean of a population is still defined as ???\mu???, but we’ll define the mean of a sample with ???\bar{x}???, pronounced “x-bar”:
???\bar{x}=\frac{\sum_{i=1}^n x_i}{n}???
Notice the capital ???N??? in the population formula and the lowercase ???n??? in the sample formula. Remember the capital ???N??? means you have included everyone (the population), and the lowercase ???n??? means you have selected just a few individuals (the sample).
## Formulas for variance
Standard deviation is the measure of how far the data is spread from the mean, and population variance for the set measures how the points are spread out from the mean.
Population variance is given by ???\sigma^2??? (pronounced “sigma squared”). The reason we define the population variance formula in terms of ???\sigma^2??? is because doing so will help us with some concepts we’ll learn later on. The formula for population variance is:
???\sigma^2=\frac{\sum_{i=1}^N (x_i-\mu)^2}{N}???
Notice that ???\mu??? is the population mean, which means that ???x_i-\mu??? gives the distance of each point from the mean, which is the deviation of each point. Then ???(x_i-\mu)^2??? is the squared deviation, we’re summing together all those squared deviations in the numerator, and then we’re dividing that result by the number of objects in the population, ???N???, in order to get population variance, ???\sigma^2???.
Finding sample variance is a very similar process to finding population variance, but we use a slightly different formula:
???S^2=\frac{\sum_{i=1}^n (x_i-\bar{x})^2}{n}???
Notice that the formula for sample variance, ???S^2???, is identical to the formula for population variance, except that we’ve swapped out ???\mu??? for ???\bar{x}??? (since ???\bar{x}??? is sample mean, whereas ???\mu??? is population mean), and we’ve changed ???N??? to ???n??? (since ???n??? refers to sample size, whereas ???N??? refers to population size).
But we need to be really careful here. While this sample variance formula is correct, it’s not usually the one we use, because it’s actually not that accurate. We won’t go into detail about why it’s not super accurate, but we’ll say that, because it’s not that accurate, we usually say that the formula above gives biased sample variance.
Interestingly, the easy way to make the sample variance formula a lot more accurate is to divide by ???n-1??? instead of ???n???. Dividing by ???n??? will underestimate sample variance, and dividing by ???n-2??? will overestimate sample variance. In other words, the better formula for sample variance, and therefore the one we want to use is
???S^2=\frac{\sum_{i=1}^n (x_i-\bar{x})^2}{n-1}???
We say that this formula gives us the unbiased sample variance. Sometimes, in order to distinguish these formulas from one another, you’ll see them written as
???S_n^2=\frac{\sum_{i=1}^n (x_i-\bar{x})^2}{n}??? for biased sample variance
and
???S_{n-1}^2=\frac{\sum_{i=1}^n (x_i-\bar{x})^2}{n-1}??? for unbiased sample variance
However, because the formula for unbiased sample variance always gives us a more accurate figure for the variance of a sample, very often we won’t worry about indicating the left-hand side of the formula as ???S_n??? or ???S_{n-1}???, because we just assume that we always want unbiased sample variance. And therefore, we agree that the formula we always want to use for sample variance is this one:
???S^2=\frac{\sum_{i=1}^n (x_i-\bar{x})^2}{n-1}???
Be careful to distinguish between biased and unbiased sample variance
## Formulas for standard deviation
Standard deviation is a measure of how much the data in a set varies from the mean. The larger the value of standard deviation, the more the data in the set varies from the mean. The smaller the value of standard deviation, the less the data in the set varies from the mean.
Population standard deviation is the positive square root of population variance. Since population variance is given by ???\sigma^2???, population standard deviation is given by ???\sigma???.
???\sigma=\sqrt{\sigma^2}=\sqrt{\frac{\sum_{i=1}^N (x_i-\mu)^2}{N}}???
So when you want to calculate the standard deviation for a population, just find population variance, and then take the square root of the variance, and you’ll have population standard deviation.
Similarly, we’ll find sample standard deviation by taking the square root of unbiased sample variance (the one we found by dividing by ???n-1???. Since sample variance is given by ???S^2???, sample standard deviation is given by ???S???.
???S=\sqrt{S_{n-1}^2}=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar{x})^2}{n-1}}???
Keep in mind that, even though we start with unbiased sample variance, when we take the square root to find sample standard deviation, we reintroduce some bias into the value. The amount of bias in the sample standard deviation just depends on the kind of data in the data set.
Here’s a table that summarizes the formulas from this section.
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# 1 Hooker’s Himalayian boiling point altitude data
Dr. Joseph Hooker collected the following data in the 1840s on the boiling point of water and the atmospheric pressure at 31 locations in the Himalayas. Boiling point is measured in degrees Fahrenheit. The pressure is recorded in inches of mercury, adjusted for the difference between the ambient air temperature when he took the measurements and a standard temperature.
The goal was to develop a model to predict the atmospheric pressure from the boiling point.
Historical note: Hooker really wanted to estimate altitude above sea level from measurements of the boiling point of water. He knew that the altitude could be determined from the atmospheric pressure, measured with a barometer, with lower pressures corresponding to higher altitudes. His interest in the above modelling problem was motivated by the difficulty of transporting the fragile barometers of the 1840s. Measuring the boiling point would give travelers a quick way to estimate elevation, using the known relationship between elevation and barometric pressure, and the above model relating pressure to boiling point.
fn.data <- "http://statacumen.com/teach/ADA2/worksheet/ADA2_WS_13_boilingpressure.txt"
boil <- read.table(fn.data, header=TRUE, skip = 2)
## 1.1(2 p) Plot the data.
Using ggplot, try to implement these features in a plot. Overlay both a straight-line regression line in blue (geom_smooth(method = lm, col = "blue", ...)), as well as a loess smooth (default) dashed line in red (geom_smooth(method = loess, col = "red", linetype = 2, ...)). Using alpha=1/5 will make the confidence bands more transparent. Also, if you plot the points last, they’ll lie on top of the lines.
Describe the key features of this plot.
## 1.2(3 p) Fit a simple linear regression, assess assumptions.
Fit a simple linear regression model for predicting pressure from boiling point. Provide output for examining residuals, outliers, and influential cases.
Looking at the plots, are there any indications that the mean pressure is not linearly related to boiling point? Are there any observations that appear to be highly influencing the fit of this model? Are there certain points or regions of the data where the model does not appear to fit well? Discuss.
Which, if any, of the standard linear regression model assumptions appears to be violated in this analysis? If you believe that some of the assumptions are violated, does it appear that deleting one or two points would dramatically improve the fit? Would you use this model for predicting pressure from boiling point? Discuss and carry out any needed analysis to support your position.
## 1.3(1 p) Interpret $$R^2$$
Interpret $$R^2$$ in the previous simple linear regression model.
## 1.4(2 p) A better model.
Decide whether transformation, or a polynomial model in boiling point, is needed to adequately summarize the relationship between pressure and boiling point. If so, perform a complete analysis of the data on this scale (that is, check for influential observations, outliers, non-normality, etc.).
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# $5$-adic expansion of $−2$
Let $\alpha = \sum_{n=0}^{\infty} a_n\ p^n$ be the expansion of a p-adic unit. So $0<a_0<p$ and $0\leq a_n<p$ for $n \geq 1$.
Show that $\beta = -\alpha$ has the expansion $\beta = \sum_{n=0}^{\infty} b_n\ p^n$ with $b_0=p-a_0$ and $b_n=p-1-a_n$ for $n\geq 1$.
I have $b_n=-a_n$. And $0>b_0>p\$ i.e $\ -p>b_0-p>0$ so $-a_0=b_0-p$ . What about the other inequality.
Use this to find the $5$-adic expansion of $−2$.
How do I do this? $\alpha=2$ then?
What if $\alpha$ is not a unit and $a_0 =0$?
• Are you familiar with the fact that $$-1=\sum_{n=0}^{\infty}(p-1)p^n?$$ Either by using the geometric series formula or by observing that if you add one to the r.h.s. you cause an infinite sequence of carries - ending up with all zeros. You can prove the first claim similarly by checking that you get the endlessly cascading carry. – Jyrki Lahtonen Mar 5 '16 at 20:33
• $\alpha + \beta = 0$, reduce modulo $p$, then modulo $p^2$ etc. To find $-2=-1-1$ write the first $-1$ like the prevoius comment and add $-1$ to the first term of the series. – Maffred Mar 5 '16 at 21:09
This is my standard sermon on the topic. I recommend Strongly that you write your $5$-adic expansions in standard $5$-ary notation, so that $\cdots dcba$ stands for $a + b\cdot5+c\cdot5^2+d\cdot5^3+\cdots$. (And I like to put semicolon to the right of the units digit instead of a period to remind us that this is $p$-adic expansion.)
Now, if you subtract $1$ from the $5$-ary number $1000000$ you get $444444$, and remember how you got it: calculating right to left, doing the same borrow-and-carry procedure that you learned in elementary school. But $5$-adically, that $1$ in the sixth place is really small, standing for $5^6$, so let’s just subtract $1$ from $0$ and get the result $\cdots44444;\,$, with $4$’s extending all the way to the left. This is your expansion of $-1$. And you can check it with the formula $a/(1-r)$ for geometric series: here $a=4$ and $r=5$, evaluating sure enough to $-1$.
Since $-1=\cdots44444;\,$, surely $-2$ is what you get by subtracting $1$ from that, namely $\cdots44443;\,$.
What about the negative of an arbitrary $p$-adic integer $z=\sum_{i\ge0}a_ip^i$? Subtract it first from $-1$ to get $\sum_{i\ge0}b_ip^i$ where $a_i+b_i=p-1$, and then add $1$ to the result. Easy, right?
It seems to me that once you get in the habit of thinking of $p$-adic numbers in the way I’ve recommended, you’ll find your text’s explanation unnecessarily complicated.
• How would you set out the answer to the first part. And what would happen if $\alpha$ is not a unit and $a_0=0$? – Polp Mar 9 '16 at 20:42
• You can answer the first part by appealing to my algorithm; and if $\alpha$ is not a unit, the algorithm still applies. The nonunit twenty has $5$-adic expansion $40;$ and hence its negative is $\cdots44410;$ — no different from the negative of $2$. – Lubin Mar 9 '16 at 21:13
• So calculate $-1-\alpha$? – Polp Mar 10 '16 at 0:35
• Exactly, and then add $1$ to make it right. – Lubin Mar 10 '16 at 4:45
• Thanks, but I do not understand what the 5-adic expansion of $-2$ would be if $\alpha$ is not a unit and $a_0=0$? – Polp Mar 10 '16 at 22:51
I have $b_n=-a_n$.
No you don't: you have $b_n=-1-a_n$.
Perhaps the simplest method is to compute $\alpha+\beta$ term by term and show that each term is $0$.
The second part is easy: you have $\alpha=2$, so $a_0=2$, and $a_n=0$ for $n \ge 1$. Now just use the formula from the first part.
• How do I get the expansion with the inequalities for the first bit? – Tony Mar 5 '16 at 20:54
• I'm afraid I don't understand your question @Tony. – TonyK Mar 6 '16 at 1:20
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#### Volume 10, issue 3 (2006)
1 C C Adams, Thrice-punctured spheres in hyperbolic 3–manifolds, Trans. Amer. Math. Soc. 287 (1985) 645 MR768730 2 I Agol, Small 3–manifolds of large genus, Geom. Dedicata 102 (2003) 53 MR2026837 3 I Agol, P Storm, W Thurston, Lower bounds on volumes of hyperbolic Haken 3–manifolds arXiv:math.DG/0506338 4 H Akiyoshi, On the Ford domains of once-punctured torus groups, Sūrikaisekikenkyūsho Kōkyūroku (1999) 109 MR1744475 5 H Akiyoshi, M Sakuma, M Wada, Y Yamashita, Ford domains of punctured torus groups and two–bridge knot groups, from: "Knot Theory: dedicated to 70th birthday of Prof. Kunio Murasugi" (editor M Sakuma) (2000) 6 H Akiyoshi, M Sakuma, M Wada, Y Yamashita, Jørgensen's picture of punctured torus groups and its refinement, from: "Kleinian groups and hyperbolic 3–manifolds (Warwick, 2001)", London Math. Soc. Lecture Note Ser. 299, Cambridge Univ. Press (2003) 247 MR2044553 7 P Alestalo, H Helling, On torus fibrations over the circle, Sonderforschungsbereich SFB-343 (1997) 8 J F Brock, Weil–Petersson translation distance and volumes of mapping tori, Comm. Anal. Geom. 11 (2003) 987 MR2032506 9 K Chan, Constructing hyperbolic 3–manifolds, Undergraduate thesis, University of Melbourne (2002) 10 Y Colin de Verdière, Un principe variationnel pour les empilements de cercles, Invent. Math. 104 (1991) 655 MR1106755 11 F Guéritaud, Triangulated cores of punctured–torus groups arXiv:math.GT/0605481 12 H Helling, The trace fields of a series of hyperbolic manifolds, Sonderforschungsbereich SFB-343 (1999) 13 T Koch, Fordsche Fundamentalbereiche hyperbolischer einfach-punktierter Torus-Bündel, Sonderforschungsbereich SFB-343 (1999) 14 M Lackenby, The canonical decomposition of once-punctured torus bundles, Comment. Math. Helv. 78 (2003) 363 MR1988201 15 M Lackenby, The volume of hyperbolic alternating link complements, \rmWith an appendix by Ian Agol and Dylan Thurston, Proc. London Math. Soc. $(3)$ 88 (2004) 204 MR2018964 16 W Menasco, Closed incompressible surfaces in alternating knot and link complements, Topology 23 (1984) 37 MR721450 17 W Menasco, M Thistlethwaite, The classification of alternating links, Ann. of Math. $(2)$ 138 (1993) 113 MR1230928 18 J Milnor, Hyperbolic geometry: the first 150 years, Bull. Amer. Math. Soc. $($N.S.$)$ 6 (1982) 9 MR634431 19 Y N Minsky, The classification of punctured-torus groups, Ann. of Math. $(2)$ 149 (1999) 559 MR1689341 20 K Murasugi, Knot theory and its applications, Birkhäuser (1996) MR1391727 21 W D Neumann, D Zagier, Volumes of hyperbolic three-manifolds, Topology 24 (1985) 307 MR815482 22 J P Otal, Le théorème d'hyperbolisation pour les variétés fibrées de dimension 3, Astérisque (1996) MR1402300 23 I Rivin, Euclidean structures on simplicial surfaces and hyperbolic volume, Ann. of Math. $(2)$ 139 (1994) 553 MR1283870 24 M Sakuma, J Weeks, Examples of canonical decompositions of hyperbolic link complements, Japan. J. Math. $($N.S.$)$ 21 (1995) 393 MR1364387 25 M B Thistlethwaite, On the algebraic part of an alternating link, Pacific J. Math. 151 (1991) 317 MR1132393
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# Measurement and QCD Analysis of the Diffractive Deep-Inelastic Scattering Cross Section at HERA
Abstract : A detailed analysis is presented of the diffractive deep-inelastic scattering process $ep\to eXY$, where $Y$ is a proton or a low mass proton excitation carrying a fraction $1 - \xpom > 0.95$ of the incident proton longitudinal momentum and the squared four-momentum transfer at the proton vertex satisfies $|t|<1 {\rm GeV^2}$. Using data taken by the H1 experiment, the cross section is measured for photon virtualities in the range $3.5 \leq Q^2 \leq 1600 \rm GeV^2$, triple differentially in $\xpom$, $Q^2$ and $\beta = x / \xpom$, where $x$ is the Bjorken scaling variable. At low $\xpom$, the data are consistent with a factorisable $\xpom$ dependence, which can be described by the exchange of an effective pomeron trajectory with intercept $\alphapom(0)= 1.118 \pm 0.008 {\rm (exp.)} ^{+0.029}_{-0.010} {\rm (model)}$. Diffractive parton distribution functions and their uncertainties are determined from a next-to-leading order DGLAP QCD analysis of the $Q^2$ and $\beta$ dependences of the cross section. The resulting gluon distribution carries an integrated fraction of around 70% of the exchanged momentum in the $Q^2$ range studied. Total and differential cross sections are also measured for the diffractive charged current process $e^+ p \to \bar{\nu}_e XY$ and are found to be well described by predictions based on the diffractive parton distributions. The ratio of the diffractive to the inclusive neutral current $ep$ cross sections is studied. Over most of the kinematic range, this ratio shows no significant dependence on $Q^2$ at fixed $\xpom$ and $x$ or on $x$ at fixed $Q^2$ and $\beta$.
Document type :
Journal articles
http://hal.in2p3.fr/in2p3-00079770
Contributor : Sabine Starita Connect in order to contact the contributor
Submitted on : Monday, January 8, 2007 - 10:32:10 AM
Last modification on : Sunday, June 26, 2022 - 11:45:55 AM
### Citation
A. Aktas, V. Andreev, T. Anthonis, S. Aplin, A. Asmone, et al.. Measurement and QCD Analysis of the Diffractive Deep-Inelastic Scattering Cross Section at HERA. European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2006, 48, pp.715-748. ⟨10.1140/epjc/s10052-006-0035-3⟩. ⟨in2p3-00079770⟩
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1. ## Functions
Functions f and g are defined for x E R by
f:x --->e^x
g:x--->2x-3
(i) Solve the equation fg(x)=7
Function h is defined as gf
(ii)Express h in terms of x and state its range
(iii)Express h inverse in terms of x.
2. ## Re: Functions
(i)x=(ln7+3)/2...its easy. take ln both sides.
(ii)h(x)=2e^x-3
its minimum value will be when the term 2e^x is minimum since 3 is constant ..2e^x can attain a minimum zero(just attain) at x=-infinity.And its maximum value will be infinity.therefore range is (-3,infinity)
(iii)for finding h inverse take log again..
Hope it helps....
3. ## Re: Functions
Note that:
$\displaystyle f \circ g(x) = f(g(x))$
So, in this case, that means:
$\displaystyle f \circ g(x) = e^{g(x)} = e^{2x-3} = (e^{2x})(e^{-3}) = \frac{(e^x)^2}{e^3} = 7$
$\displaystyle e^x = \sqrt{7e^3}$, and taking logs, we get:
$\displaystyle x = \log(\sqrt{7e^3}) = \log((\sqrt{7})(e^{\frac{3}{2}}))$
$\displaystyle = \log(\sqrt{7}) + \log(e^{\frac{3}{2}}) = \log(\sqrt{7}) + \frac{3}{2} = \frac{\log(7) + 3}{2}$
Similarly,
$\displaystyle g \circ f(x) = 2(e^x) - 3$.
Since $\displaystyle e^x$ ranges from (0,∞), it's clear that $\displaystyle 2(e^x)$ also ranges from (0,∞) and thus the range of $\displaystyle g \circ f$ is (-3,∞).
Consequently, $\displaystyle h^{-1} = f^{-1} \circ g^{-1}$ is only defined on (-3,∞). Can you figure out what it is, in terms of x?
4. ## Re: Functions
i solved it maybe it is : (ln(x+3)/2)=h-1(x)
here domain of h-1(x) is (-3,infinity) same as the range ..
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# Question
Random samples of size 5, 20, and 80 are drawn from a population with a mean of μ = 100 and a standard deviation of σ = 15.
a. Give the mean of the sampling distribution of y for each of the three sample sizes.
b. Give the standard deviation of the sampling distribution of y for each of the three sample sizes.
c. Based on the results obtained in parts (a) and (b), what do you conclude about the accuracy of using the sample mean y as an estimate of population mean μ?
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# MeanCI
0th
Percentile
##### Confidence Interval for the Mean
Collection of several approaches to determine confidence intervals for the mean. Both, the classical way and bootstrap intervals are implemented for both, normal and trimmed means.
Keywords
univar
##### Usage
MeanCI(x, sd = NULL, trim = 0, method = c("classic", "boot"), conf.level = 0.95, sides = c("two.sided", "left", "right"), na.rm = FALSE, ...)
##### Arguments
x
a (non-empty) numeric vector of data values.
sd
the standard deviation of x. If provided it's interpreted as sd of the population and the normal quantiles will be used for constructing the confidence intervals. If left to NULL (default) the sample sd(x) will be calculated and used in combination with the t-distribution.
trim
the fraction (0 to 0.5) of observations to be trimmed from each end of x before the mean is computed. Values of trim outside that range are taken as the nearest endpoint.
method
A vector of character strings representing the type of intervals required. The value should be any subset of the values "classic", "boot". See boot.ci.
conf.level
confidence level of the interval.
sides
a character string specifying the side of the confidence interval, must be one of "two.sided" (default), "left" or "right". You can specify just the initial letter. "left" would be analogue to a hypothesis of "greater" in a t.test.
na.rm
a logical value indicating whether NA values should be stripped before the computation proceeds. Defaults to FALSE.
...
further arguments are passed to the boot function. Supported arguments are type ("norm", "basic", "stud", "perc", "bca"), parallel and the number of bootstrap replicates R. If not defined those will be set to their defaults, being "basic" for type, option "boot.parallel" (and if that is not set, "no") for parallel and 999 for R.
##### Details
The confidence intervals for the trimmed means use winsorized variances as described in the references.
Use do.call, rbind and lapply for getting a matrix with estimates and confidence intervals for more than 1 column. (See examples!)
##### References
Wilcox, R. R., Keselman H. J. (2003) Modern robust data analysis methods: measures of central tendency Psychol Methods, 8(3):254-74
Wilcox, R. R. (2005) Introduction to robust estimation and hypothesis testing Elsevier Academic Press
t.test, MeanDiffCI, MedianCI, VarCI
• MeanCI
##### Examples
x <- d.pizza\$price[1:20]
MeanCI(x, na.rm=TRUE)
MeanCI(x, conf.level=0.99, na.rm=TRUE)
MeanCI(x, sides="left")
# same as:
t.test(x, alternative="greater")
MeanCI(x, sd=25, na.rm=TRUE)
# the different types of bootstrap confints
MeanCI(x, method="boot", type="norm", na.rm=TRUE)
MeanCI(x, trim=0.1, method="boot", type="norm", na.rm=TRUE)
MeanCI(x, trim=0.1, method="boot", type="basic", na.rm=TRUE)
MeanCI(x, trim=0.1, method="boot", type="stud", na.rm=TRUE)
MeanCI(x, trim=0.1, method="boot", type="perc", na.rm=TRUE)
MeanCI(x, trim=0.1, method="boot", type="bca", na.rm=TRUE)
MeanCI(x, trim=0.1, method="boot", type="bca", R=1999, na.rm=TRUE)
# Getting the MeanCI for more than 1 column
round( do.call("rbind", lapply(d.pizza[, 1:4], MeanCI, na.rm=TRUE)), 3)
Documentation reproduced from package DescTools, version 0.99.19, License: GPL (>= 2)
### Community examples
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Free Version
Easy
# Intersection of Planes
ACTMAT-NYCCCL
If two planes intersect, then what is their intersection?
A
$\text{Point}$
B
$\text{Line Segment}$
C
$\text{Line}$
D
$\text{Ray}$
E
$\text{Plane}$
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# Inner product for Dirac Spinors
1. Mar 12, 2010
### LAHLH
1. The problem statement, all variables and given/known data
Show that $$\psi (\gamma^a\phi)=-(\gamma^a\phi)\psi$$
2. Relevant equations
Maybe $$\{\gamma^a, \gamma^b\}=\gamma^a\gamma^b+\gamma^b\gamma^a=2\eta^{ab}I$$
Perhaps also:
$$(\gamma^0)^{\dag}=\gamma^0$$ and $$(\gamma^i)^{\dag}=-(\gamma^i)$$
3. The attempt at a solution
$$\psi_{\mu}[(\gamma^a)^{\mu\nu}\phi_{\nu}]$$
$$=\psi_{\mu}[(((\gamma^a)^*)^{\dag})^{\nu\mu}\phi_{\nu}]$$
$$=-[(((\gamma^a)^*))^{\nu\mu}\psi_{\mu}]\phi_{\nu}$$
Which looks almost correct except the *, and also I'm not sure if I was supposed to assume that a can only refer to spatial indices, not the 0 which is equal to its hermitian conj, not minus it.
Thanks for any help
2. Mar 14, 2010
Anyone?
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# zbMATH — the first resource for mathematics
Estimates of sums of zero multiplicities for eigenfunctions of the Laplace-Beltrami operator. (English. Russian original) Zbl 1149.58011
J. Math. Sci., New York 146, No. 1, 5509-5512 (2007); translation from Fundam. Prikl. Mat. 11, No. 5, 85-90 (2005).
Summary: We obtain an upper estimate $$N-\chi(M)$$ for the sum $$\mathbb Q_N$$ of singular zero multiplicities of the $$N$$th eigenfunction of the Laplace-Beltrami operator on the two-dimensional, compact, connected Riemann manifold $$M$$, where $$\chi M$$ is the Euler characteristic of $$M$$. Stronger estimates, but equivalent asymptotically $$(N\to\infty )$$, are given for the cases of the sphere $$S ^{2}$$ and the projective plane $$\mathbb R^{2}$$. Asymptotically sharper estimates are shown for the case of a domain on the plane.
##### MSC:
58J50 Spectral problems; spectral geometry; scattering theory on manifolds
Full Text:
##### References:
[1] N. Aronszajn, ”A unique continuation theorem for solution of elliptic partial differential equations of second order,” J. Math. Pures Appl., 36, 235–249 (1957). · Zbl 0084.30402 [2] L. Bers, ”Local behavior of solutions of general linear elliptic equations,” Comm. Pure Appl. Math., 8, 473–496 (1955). · Zbl 0066.08101 [3] R. Courant and D. Hilbert, Methods of Mathematical Physics, Vol. 1, Wiley (1991). · JFM 57.0245.01 [4] V. N. Karpushkin, ”Multiplicities of singularities of eigenfunctions for the Laplace-Beltrami operator,” Funct. Anal. Appl., 29, No. 1, 62–64 (1995). · Zbl 0843.58122 [5] V. N. Karpushkin, ”On the number of components of the complement to some algebraic curves,” Russ. Math. Surv., 57, No. 6, 1228–1229 (2002). · Zbl 1049.14043 [6] Å. Pleijel, ”Remarks on Courant’s nodal line theorem,” Comm. Pure Appl. Math., 9, 543–550 (1956). · Zbl 0070.32604
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching.
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# Do complex eigenvalues of a real matrix imply a rotation-dilation?
This is part of a bigger proof that if there is a compact set, $K \subset \mathbb R^n$ such that the linear transformation $L$ maps $K$ into its interior, the eigenvalues $\lambda_i$ are all of absolute value less than 1. Clearly, if $L(K)\subset \operatorname{int}(K)$ then $L^n(K)\subset \operatorname{int}(K)$.
The easiest case seems to be: If the eigenvalue were an $n$th root of unity, then $L^n$ must have some fixed point on the boundary, a contradiction.
I can't even seem to prove it for complex eigenvalues of absolute value greater than $1$ or for eigenvalues of absolute value $1$ which are not roots of unity.
My attempts: 1) Say $|\lambda|>1$ then it seems like $L$ would take the vectors off to infinity. However, I am worried there is a case where $L$ takes some vector, lengthens it, and maps it to some other vector, and on the next iteration it undoes, or something like that.
2) Say $|\lambda|=1$. If a linear transformation on $\mathbb R^n$ has a pair of complex eigenvalues of absolute value 1 (but not roots of unity), is it true that this always corresponds to a rotation on a two dimensional subspace? If so, then it seems like this is an irrational rotation. So start with some point on the boundary of $K$ that is on the subspace of rotation, then look at the infinite union of $L^i(K)$ for $i>1$. The original point is a limit point of this union, and since $K$ was compact and since $L$ is continuous since it is a finite dimensional linear operator, $L^i(K)$ are all compact....but this isn't good because now the point is the limit point of an infinite union of compact sets which may not be compact and thus don't need to contain their limit points. But if it did contain this point this would be a contradiction.
Please and thank you for helping :D
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It's worth noting that each linear transformation must have a fixed point--namely the zero vector. – Cameron Buie Mar 23 '13 at 16:00
I don't quite follow. We want to assume that $0\in int(K)$ so having this fixed point doesn't really seem to help. – Steven-Owen Mar 23 '13 at 17:43
You're right, it doesn't help. I'm just pointing out that having a fixed point doesn't lead to a contradiction on its own, as you claimed. Now, you are right that having a fixed point on the boundary leads to a contradiction. – Cameron Buie Mar 23 '13 at 17:55
I'll try to formulate in a way that does not depend on the fact that the real $n$-dimensional space $V$ being acted upon is $\Bbb R^n$, in other words it does not depend on choosing a basis in $V$.
Let $\def\C{\Bbb C}V_\C$ be the complexification of $V$, which is a complex vector space built from the real vector space $V\oplus V$ by defining multiplication by $\def\ii{\mathbf i}\ii\in\C$ by $\ii\cdot(v,w)=(-w,v)$, and let $L_\C:V_\C\to V_\C$ be the complexification of $L$, defined by $L_\C(v,w)=(L(v),L(w))$ (it is clearly complex-linear). Now $L_\C$ as complex-linear map has the same characteristic polynomial as $L$ has as real-linear map (indeed on suitable bases they have identical matrices), so for every complex eigenvalue $\lambda=a+b\ii$ of $L$ there is a corresponding eigenvector in $(v,w)\in V_\C$. This means that $$(L(v),L(w))=(a+b\ii)(v,w)=(av-bw,bv+aw).$$ One easily sees that $v,w\in V$ must be $\Bbb R$-linearly independent in the case $\lambda\notin\Bbb R$ of interest here, that is $b\neq 0$: supposing $cv+dw=0$ and applying $L$ one gets after simplification $b(-cw+dv)=0$, so $dv-cw=0$, and forming linear combinations with the supposed relation gives $(c^2+d^2)v=0$ and $(d^2+c^2)w=0$, which contradicts $(v,w)\neq(0,0)$. So the $\Bbb R$-subspace $\langle v,w\rangle_\Bbb R\subseteq V$ is the $2$ dimensional and $L$-stable, with the restriction of $L$ to it given by the matrix $$\begin{pmatrix}a&b\\-b&a\end{pmatrix}.$$
I guess this gives what you asked in the title.
For the "bigger proof" you need to modify the statement first to exclude taking the empty set for $K$.
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Sorry, why must they be linearly independent over the real numbers? Is it because if they weren't then $cv=w$ for real $c$ and thus multiplying them by a complex number $\lambda$ just had the effect of a real scalar since it would $(av-bcv,bv+acv)=((a-bc)v,(b+cv)v)$ where $a,b,c$ are real numbers? – Steven-Owen Mar 25 '13 at 13:56
I don't know if what I said made sense, sorry. Could you just elaborate briefly on the implication from $b\neq0$ to $v,w$ being linearly independent over the reals. – Steven-Owen Mar 25 '13 at 13:58
@ricky Supposing $v=\lambda x$ and $w=\mu x$ for a same vector $x$, with $\lambda,\mu\in\Bbb R^\times$, one has $\lambda(b\lambda+a\mu)x=\lambda(bv+aw)=L(\lambda w)=L(\mu v)=\mu(av-bw)=\mu(a\lambda-b\mu)x$, and taking the difference gives $b(\lambda^2+\mu^2)x=0$ in which none of the scalar and vector factors on the left can be $0$, a contradiction. – Marc van Leeuwen Mar 25 '13 at 14:21
If the above seems harder than it should be, morally if $L(v)\in\langle v\rangle_\Bbb R$, then $v$ has a real eigenvalue, which would also be the eigenvalue of $(v,w)$ in $V_\Bbb C$, contradicting that the latter has eigenvalue $a+b\mathbf i$. – Marc van Leeuwen Mar 25 '13 at 14:27
Yes, in my comment $\lambda$ was just a real scalar, no relation to an eigenvalue. What you do amounts to taking $x=w$, $\lambda=c$, $\mu=1$ in what I said, so I am saying $c(bc+a)w=c(bv+aw)=L(cw)=L(v)=av-bw=(ac-b)w$, and taking the difference between the two ends gives $b(c^2+1)w=0$ contradiction. Seems like you're saying essentially the same thing. – Marc van Leeuwen Mar 25 '13 at 14:41
1. If $\lambda$ is an eigenvalue of a real matrix $A$, then it has a nonzero (complex) eigenvector $v$ corresponding to it.
2. If $v$ is real, then so is $\lambda$, and we're done, because if we had $\lvert \lambda\rvert\geq 1$, there would be either a point in $K$ which explodes into infinity with $A^n$, or a fixed point of $A^2$ on $K$'s border (this is because $K$ must contain a ball around $0$).
3. Otherwise, it's easy to see that then $\overline v$ corresponds to $\overline \lambda$ (because $\overline A=A$ and $\overline{Av}=\overline{\lambda v}$).
4. Furthermore, we can assume that $v+\overline v$ is a nonzero real vector (equal to twice the real part of $v$). Otherwise $v$ would be purely imaginary, $iv$ would be a real eigenvector corresponding to $\lambda$, so we can use the same argument as above.
5. From now on, we will only consider restrictions of $A$ and $K$ to the plane spanned by real and imaginary parts of $v$. We can assume that $v=(1,i)^T$, other coordinates zero (by changing coordinates if necessary).
6. Then we have that $A^n(v+\overline v)=\lambda^nv+\overline\lambda^n\overline v$, likewise for $-i(v-\overline v)$; choose $r,\theta$ so that $\lambda=re^{i\theta}$. You can see by inspection that $A^n$ is a dilation by $r^n$ followed by a rotation by $n\theta$. This means that if $r\geq 1$, then either it blows up some points in $K$ into infinity, or it keeps the points of maximal distance from $0$ on the circle they belong to, both yielding a contradiction.
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Thank you for the help. A couple clarification questions: 1) What do you mean in 5. by real and imaginary parts of $v$? Do you mean writing $v$ as $x+iy$ where $x,y$ are real vectors and looking at the span of ${x,y}$ with the scalar field being $C$? 2) In 6. when you say likewise for $-i(v-\bar v)$ are you just saying $A^n(-i(v-\bar v))= -iA^n(v-\bar v)=-i(\lambda^nv-\bar\lambda^n\bar v)$. So what? 3) In 6. again, what is this point in $K$? It seems like we are only talking about complex vectors. – Steven-Owen Mar 23 '13 at 19:12
@ricky: 1) no, i mean the real span, 2) yes, that's what I meant; $v+\overline v$ and $i(v-\overline v)$ are (up to a real scalar) the real and complex parts of $v$, so you can determine what $A$ is by looking at their images; 3) this point in $K$ is just any nonzero point in $K$ (restricted to the plane where $A$ is the dilation rotation) – tomasz Mar 23 '13 at 22:13
Here is some rough ideas. Let $x_0=\arg\min_{x\in K}\|x\|_2$. By considering the sequence $x_n=L^nx$, we see that $\{x_n\}$ has a convergent subsequence and in turn $L$ has a fixed point $u$ in the interior of $K$. This $u$ must be the origin. Otherwise, as $L$ is linear, the farthest boundary point of $K$ on the span of $u$ is also a fixed point of $L$, which is a contradiction to the problem's assumption.
Now, define $K'=\{x\circ z:\, z=(z_1,\ldots,z_n)^T\in\mathbb{C}^n,\, |z_j|=1\ \forall j\,\}$, where $x\circ z$ denotes the Hadamard (i.e. entrywise) product of $x$ and $z$. Then $K'$ is a compact set in $\mathbb{C}^n$ and the natural extension of $L$ to $\mathbb{C}^n$ maps $K'$ into its interior. If $(\lambda,v)$ is an eigenpair of $L$ over $\mathbb{C}$, by considering the farthest boundary point of $K'$ on the line spanned by $v$, we see that $|\lambda|<1$.
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# 20120822¶
I finally started to work on the “regions problem” in lino.modlib.countries.
countries.City is now designed to contain all geographic areas that are smaller than a Country (in the meaning of a sovereign state) and bigger than a Street.
The new choicelist CityTypes is an attempt to make a universal classification of the words that designate such areas. A perfect classification is probably not possible, and it will possibly still evolve.
There are “country drivers” to limit the list of possible CityTypes for a given Country.
Partner.region is no longer a simple text field but also a ForeignKey.
The choices for Partner.region are Cities with a type < 50 The choices for Partner.city are Cities with a type >= 50.
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## Hermite differential equation – generating functions
Required math: calculus
Required physics: none
Hermite’s differential equation shows up during the solution of the Schrödinger equation for the harmonic oscillator. The differential equation can be written in the form
$\displaystyle \frac{d^{2}f}{dy^{2}}-2y\frac{df}{dy}+(\epsilon-1)f=0$
but an analysis of the series solution of this equation shows that the parameter ${\epsilon}$ has to have the form
$\displaystyle \epsilon=2n+1$
for some integer ${n}$, so we can rewrite the differential equation as
$\displaystyle \frac{d^{2}f}{dy^{2}}-2y\frac{df}{dy}+2nf=0$
We know the solutions of this equation are polynomials in ${y}$, and we got (from the series solution) a recursion formula for the coefficients of the polynomials, but a recursion formula can be difficult to work with, and it turns out that there is another form that can be used to work with these polynomials. This uses the idea of the generating function.
The idea is that we can write a function ${S(y,s)}$, where ${y}$ is the same ${y}$ as in the differential equation, and ${s}$ is a kind of dummy variable that allows us to do calculations (as we’ll see in a moment). Suppose we define this function as follows:
From the expansion of the exponential in a Taylor series, we can also write this as
$\displaystyle S(y,s)$ $\displaystyle =$ $\displaystyle \sum_{m=0}^{\infty}\frac{(-s^{2}+2sy)^{m}}{m!}$ $\displaystyle$ $\displaystyle =$ $\displaystyle \sum_{m=0}^{\infty}\frac{s^{m}(2y-s)^{m}}{m!}$
At first (and probably second) glance, this formula seems to have little relation to Hermite polynomials, but let’s write out the first few terms of the series
$\displaystyle S(y,s)$ $\displaystyle =$ $\displaystyle 1+\frac{s(2y-s)}{1!}+\frac{s^{2}(2y-s)^{2}}{2!}+\frac{s^{3}(2y-s)^{3}}{3!}+...$ $\displaystyle$ $\displaystyle =$ $\displaystyle 1+2ys+(-1+2y^{2})s^{2}+(-2y+\frac{4}{3}y^{3})s^{3}+...$
In the second line, we regrouped the series so that terms with the same power of ${s}$ are grouped together. The ${m^{th}}$ term in the series contains terms involving ${s}$ to the ${m^{th}}$ and higher powers only, so if we want to isolate those terms for a particular power (say the ${n^{th}}$ power) of ${s}$ we need look at only the first ${n}$ terms of the series. What do we get if we look at terms involving each successive power of ${s}$, starting with the zeroth power? As can be seen above, the term involving ${s^{m}}$ is multiplied by a polynomial in ${y}$ and by comparing these polynomials with those obtained by our earlier definition of the Hermite polynomials, we can see that each polynomial here is ${H_{m}(y)/m!}$. That is
Obviously we haven’t proved this in general, but this function may also be taken as the definition of Hermite polynomials, as the other definition that we used earlier can be derived from it, as we’ll see at the end of this post.
The Hermite polynomials can be obtained from this generating function by taking derivatives, as follows. Since the ${j^{th}}$ derivative of ${s^{m}}$ is zero if ${m, taking this derivative will eliminate all terms with ${m The ${j^{th}}$ derivative of ${s^{j}}$ is the constant ${j!}$. For all higher powers where ${m>j}$, the ${j^{th}}$ derivative will leave a term ${s^{m-j}}$. So if we take the ${j^{th}}$ derivative of ${S(y,s)}$ and then set ${s=0}$ we will isolate the single term involving ${H_{j}(y)}$:
$\displaystyle \frac{d^{j}S(y,s)}{ds^{j}}\Big|_{s=0}$ $\displaystyle =$ $\displaystyle j!\frac{H_{j}(y)}{j!}$ $\displaystyle$ $\displaystyle =$ $\displaystyle H_{j}(y)$
This is the reason that ${S(y,s)}$ is called a generating function: it provides a relatively simple way of generating all the Hermite polynomials.
Since we started by defining the generating function, we should prove that the polynomials that it generates really are solutions of Hermite’s differential equation. We can do this by taking derivatives of the generating function (but without the step of setting ${s=0}$). We take derivatives of 1 and 2 and then set them equal to each other.
$\displaystyle \frac{\partial S}{\partial y}$ $\displaystyle =$ $\displaystyle 2se^{-s^{2}+2sy}$ $\displaystyle$ $\displaystyle =$ $\displaystyle \sum_{m=0}^{\infty}\frac{2s^{m+1}}{m!}H_{m}(y)\mathrm{\: from\;(1)}$ $\displaystyle \frac{\partial S}{\partial y}$ $\displaystyle =$ $\displaystyle \sum_{m=0}^{\infty}\frac{1}{m!}\frac{dH_{m}}{dy}s^{m}\:\mathrm{from}\;(2)$
Now we use the old trick of requiring these two results to be equal for all values of ${s}$, which implies that the coefficients of each power of ${s}$ must be equal independently. That is
$\displaystyle \sum_{m=0}^{\infty}\frac{2s^{m+1}}{m!}H_{m}(y)$ $\displaystyle =$ $\displaystyle \sum_{m=0}^{\infty}\frac{1}{m!}\frac{dH_{m}}{dy}s^{m}$ $\displaystyle \sum_{m=1}^{\infty}\frac{2s^{m}}{(m-1)!}H_{m-1}(y)$ $\displaystyle =$ $\displaystyle \sum_{m=1}^{\infty}\frac{1}{m!}\frac{dH_{m}}{dy}s^{m}$
In the second line, we adjusted the summation index on the left so that the power of ${s}$ was ${s^{m}}$. On the right, we dropped the ${m=0}$ term since ${dH_{0}/dy=0}$ anyway (since ${H_{0}=1}$). The two sums are now aligned, so we can say
$\displaystyle \frac{2}{(m-1)!}H_{m-1}(y)$ $\displaystyle =$ $\displaystyle \frac{1}{m!}\frac{dH_{m}}{dy}$ $\displaystyle 2mH_{m-1}$ $\displaystyle =$ $\displaystyle H_{m}'$
By a similar process we can take the other derivative with respect to ${s}$:
$\displaystyle \frac{\partial S}{\partial s}$ $\displaystyle =$ $\displaystyle (-2s+2y)e^{-s^{2}+2sy}$ $\displaystyle$ $\displaystyle =$ $\displaystyle \sum_{m=0}^{\infty}\frac{(-2s+2y)s^{m}}{m!}H_{m}\:\mathrm{from}\;(1)$ $\displaystyle \frac{\partial S}{\partial s}$ $\displaystyle =$ $\displaystyle \sum_{m=1}^{\infty}\frac{m}{m!}H_{m}s^{m-1}\:\mathrm{from}\;(2)$
We have ignored the ${m=0}$ term in the last line, since the derivative of the first term in the series with respect to ${s}$ is zero. Aligning the powers of ${s}$ gives
$\displaystyle -\sum_{m=1}^{\infty}\frac{2s^{m}}{(m-1)!}H_{m-1}+\sum_{m=0}^{\infty}\frac{2ys^{m}}{m!}H_{m}$ $\displaystyle =$ $\displaystyle \sum_{m=0}^{\infty}\frac{1}{m!}H_{m+1}s^{m}$ $\displaystyle -2mH_{m-1}+2yH_{m}$ $\displaystyle =$ $\displaystyle H_{m+1}$
This relation is valid for all ${m}$ even though the ${m=0}$ case is a bit fortuitous. With ${m=0}$ we get ${2yH_{0}=H_{1}}$ which is true, since ${H_{0}=1}$ and ${H_{1}=2y}$.
From these results we can show that the polynomials do in fact solve Hermite’s differential equation. We do this by showing that the results above allow us to reconstruct the equation. From the second result:
$\displaystyle H_{m+1}$ $\displaystyle =$ $\displaystyle 2yH_{m}-2mH_{n-1}$ $\displaystyle H'_{m+1}$ $\displaystyle =$ $\displaystyle 2H_{m}+2yH'_{m}-2mH'_{n-1}$
From the first result, ${2mH'_{m-1}=H_{m}''}$, and ${H'_{m+1}=2(m+1)H_{m}}$ so substituting these into the last line above, we get
$\displaystyle H_{m}''-2yH'_{m}+2mH_{m}=0$
which is Hermite’s equation. QED.
One final bit of business is to show that the generating function approach is equivalent to the other definition of Hermite polynomials, that is, that it is equivalent to saying
$\displaystyle H_{n}\equiv(-1)^{n}e^{x^{2}}\frac{d^{n}}{dx^{n}}e^{-x^{2}}$
The generating function 1 can be written as
$\displaystyle S(y,s)$ $\displaystyle \equiv$ $\displaystyle e^{-s^{2}+2sy}$ $\displaystyle$ $\displaystyle =$ $\displaystyle e^{y^{2}-(s-y)^{2}}$
so taking the derivative, we get
$\displaystyle \frac{\partial^{n}S}{\partial s^{n}}$ $\displaystyle =$ $\displaystyle e^{y^{2}}\frac{\partial^{n}}{\partial s^{n}}e^{-(s-y)^{2}}$ $\displaystyle$ $\displaystyle =$ $\displaystyle (-1)^{n}e^{y^{2}}\frac{\partial^{n}}{\partial y^{n}}e^{-(s-y)^{2}}$
since for any function ${f(s-y)}$, ${\partial f/\partial s=-\partial f/\partial y}$. Setting ${s=0}$, we reclaim the original definition:
$\displaystyle \frac{\partial^{n}S}{\partial s^{n}}\Big|_{s=0}=(-1)^{n}e^{y^{2}}\frac{\partial^{n}}{\partial y^{n}}e^{-y^{2}}$ so the two definitions are equivalent.
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# Total squared curvature of surfaces in Riemannian manifolds
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Ernst Kuwert,Albert-Ludwigs-Universität Freiburg im Breisgau
Fine Hall 314
We discuss the problem of minimizing the total squared curvature of compact surfaces in closed Riemannian manifolds. In particular, we present an area bound in terms of the curvature for many manifolds.
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# A generalized procedure for determining transient response of third order systems
• 1.28 MB
• English
by
Naval Postgraduate School , Monterey, California
The Physical Object ID Numbers Contributions Naval Postgraduate School (U.S.) Pagination 1 v. : Open Library OL25129790M
TABLEOFCONTENTS Section Title Page uction 1 tsatGeneralizingtheEquationofa ThirdOrderSystemwithOneZero 5 pmentoftheGeneralEquation 10 U. complex. This document derives the step response of the general second-order step response in detail, using partial fraction expansion as necessary.
### Details A generalized procedure for determining transient response of third order systems PDF
Transient response of the general second-order system Consider a circuit having the following second-order transfer function H(s): v out (s) v in (s) =H(s)= H 0 1+2ζs ω 0 + s ω 0 2 (1) where File Size: KB.
These probes and the TPD have been found to be very helpful in determining the thermal response, viz., thermal resistivity, thermal diffusivity and effusivity, and specific heat, of different.
correlates directly to the settling characteristics (transient response) of a second-order PLL, which is what makes it an attractive loop control parameter. A third-order PLL, on the other hand, has an open-loop response, which has the form: () 2() Ks OL s s H s α β + + = (3) In equation 3, α defi nes the zero and β the pole of A generalized procedure for determining transient response of third order systems book open.
Journal of Sound and Vibration (I ) 29(2), THE TRANSIENT RESPONSE OF CERTAIN THIRD-ORDER NON-LINEAR SYSTEMS H. SRIRANGARAJAN AND P. SRIN1VASAN Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India (Received 12 February ) In this paper a method of solving certain third-order non-linear systems by using the method of Cited by: 6.
LINEAR SYSTEM RESPONSE OBJECTIVES The output produced by an operational amplifier (or any other dynamic system) in response to a particular type or class of inputs normally pro vides the most important characterization of the system. The purpose ofFile Size: 1MB.
The previous page introduced the zero input / zero state method for finding the transient response of a system given the defining system differential equation. However, it a system is more commonly, and conveniently, solved starting from the system transfer function or solved from a.
Prof. C.K. Tse: First Order Transient A simple first-order RC circuit ®Let us consider a very simple dynamic circuit, which contains one capacitor.
®After t = 0, the circuit is closed. So, we can easily write ®and ®Thus, we have ®Thus, we have ®If the initial condition is vC(0+) = 0, then A = –V o.
®Thus, the solution is fi Vo for t>0File Size: KB. Identification of inverse response processes using second order model based on transient step responses was studied by Balaguer et al.
[8]. Jeng and Lin [9] proposed a PID controller for stable. ELEC Tim Woo Spring /10 Chapter 5 - 3 Expected Outcome • In this chapter, you will be able to – Analysis the system performance with the use of transient and frequency response tools • Impulse response • Step response • Ramp response • Bode plot – Evaluate the transient and frequency responses of the first- and second-order continuous-time and discrete-time LTI systems.
and overshoot.
### Download A generalized procedure for determining transient response of third order systems EPUB
Higher order systems are based on second order systems. In case of mechanical second order systems, energy is stored in the form of inertia whereas in case of electrical systems, energy can be stored in a capacitor or inductor.
Standard form of second order system is given by: Where: ωn Is the natural frequencyFile Size: KB. In this article we propose an identification method for second order inverse response systems based on the process reaction curve.
In this sense the information to be used for the identification algorithm is the same as the one considered in the identification procedures of integrating processes with inverse response presented in [5], [4].Cited by: Review of First- and Second-Order System Response1 1 First-Order Linear System Transient Response The dynamics of many systems of interest to engineers may be represented by a simple model containing one independent energy storage element.
For example, the braking of an automobile,File Size: KB. Power electronic converters are used in a wide range of applications as well as being the enabling technology for interfacing the alternative energy resources and many loads in modern power systems.
The methodology of developing the so-called dynamic average-value models (AVMs) for such converters is based on averaging the variables (currents and voltages) within a switching interval resulting Cited by: 3. First-Order Circuits 29 Complete Response = Natural Response + Forced Response (Stored Energy) (Independent Source) 0 0 0 For 0 1 (()) 1 t SS t S nf t t n f t S t vt V V V e Ve V e vt v t vVe vt V e t Circuit Theory; Jieh-Tsorng Wu Transient Response and Steady-State Response 7.
First-Order Circuits 30 Complete Response = Transient Response File Size: KB. Shareable Link. Use the link below to share a full-text version of this article with your friends and colleagues.
Learn more. c imperial College of Science and Technology (University of London) TRANSIENT RESPONSE OF MECHANICAL STRUCTURES USING MODAL ANALYSIS. In this chapter, let us discuss the time response of second order system.
Consider the following block diagram of closed loop control system. Here, an open loop transfer function, $\frac{\omega ^2_n}{s(s+2\delta \omega_n)}$ is connected with a unity negative feedback. The applet below shows the response of a third order system with a cubic nonlinearity to a sine input.
parameters (,w, ) The applet shows that for w from to the frequency of the nonlinear response remains tied to the applied frequency while for the linear case the response is the sum of components at the natural frequency and applied frequency.
Adding a pole to a general second order system makes it a third order system and the dynamics can change dramatically. One example I can think of in which adding a pole or zero does not change the system dynamics dramatically is when the pole or zero is at much higher frequency than the pair of poles of the second order system.
y is the response of the measurement system component, x is the input to the measurement system component, n is the order of the system. Many measurement system components can be modeled by either first or second order differential equations.
### Description A generalized procedure for determining transient response of third order systems PDF
For example: dy(t) y(t) K x(t) dt (14) could be an equation that models the dynamic behavior of a. Time Response of a Second Order Control System Subjected to Unit Ramp Input Function Time Response of a Second Order Control System Subjected to Impulse Input Function Time Response of a Third Order Control System Effect of First Order Term Time Constant on Time Response of Third Order Control.
series or parallel with either a voltage or current source we will form a RLC or second-order circuit. It is called a second-order circuit because of the second-order differential required to solve for the voltage or current.
One of the most common uses for a second order. Eytan Modiano Slide 3 Second order RC circuit •System with 2 state variables – Described by two coupled first-order differential equations •States – Voltage across the capacitor - V 1 – Current through the inductor - i L •What to obtain state equations of the form: x’ = Ax – Need to obtain expression for dv 1/dt in terms of V 1 and i L – Need to obtain expression for diFile Size: KB.
The Korteweg-de Vries equation is a third order (partial) differential equation, describing waves on a shallow surface. I can't think of an example off the top of my head that isn't a PDE, but an example of a 4th order ODE would be the Euler-Bernoulli equation.
The Euler-Bernoulli equation describes how much a beam deflects under an applied load. The generalized procedure used in those methods consists of 3 steps Step 1: Calculate Base Shear = Factor f * Weight W where "f" is calculated from terms which take into consideration the Importance factor of the building, Site Class and soil characteristics, etc.
W is the total vertical weight derived from dead weight of the building and other imposed weights. We show that in the main case, system is transformed to a third-order system of nonhomogeneous linear first-order difference equations, which can be explicitly solved. This idea appeared for the first time in [ 24 ] for the case of the scalar equation with constant coefficients corresponding to system () and was also used later in [ 1, 4 ].Cited by: Frequency Response of Second-Order Systems.
The animated plot below shows the magnitude and phase of the transfer function plotted as a function of the non-dimensional ratio of the input frequency to the natural frequency for different values of the damping ratio.
() Proper eigenvalue solution for the transient response of multidimensional heat transfer systems. Communications in Numerical Methods in Engineering() Thermocapillary instability in a horizontal liquid layer subjected to a transverse magnetic field and by: However, after a discretization procedure, the optimization problem can be formulated as a nonlinear programming problem, as performed in (Battistelli et al.
) at the aim of determining the optimal size of supercapacitor storage systems for transportation systems. In mathematical terms, the constrained optimization problem can be summarized as:Cited by: 4. It is important for the control system analyst to understand the complete relationship of the complex-frequency representation of a linear system, the poles and zeros of its transfer function, and its time-domain response to step and other inputs.
In such areas as signal processing and control, many of the analysis and designed collations are done in the complex-frequency plane, where a system Author: Wei Yan, Yong Chun Yang, Xu Feng Guo.Lecture Transient and Steady-State Responses of LTI Differential Systems V 6\VWHP QWLDO HUH HVILIIR/7,RQV'S 5HV G\ 6WDWH DHGWQQW6D 7UDQVLH The transient response (also called natural response) of a causal, stable LTI differential system is the homogeneous response, i.e., with the input set to File Size: 34KB.Transient Response of a Second Order Model (Section ) For problems a.
Compute the natural frequency n and damping ratio. b. Compute the eigenvalues 1 and 2. c. State whether the system is underdamped, or overdamped.
d. Compute the time constant for each mode. e.
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# Nisnevich topology on non-(locally) Noetherian schemes
Background
Lurie has in DAG XI a definition (given below) of a Nisnevich cover for arbitrary commutative rings, which reduces to the usual one for Noetherian rings. It boils down to being a etale covering family admitting local sections over a different, finite, cover of a particular sort. In particular, we can assume wlog it is a finite etale family. The usual definition of a Nisnevich cover of schemes uses the (locally) Noetherian assumption and I would like to translate this into the Lurie style definition, but my algebraic geometry-foo is not up to scratch. This possibly is a simple question, but bear with me.
Details
We will work initially in $Ring$, so that what we are describing is really a cocovering family, but the translation to $Aff = Ring^{op}$ is of course trivial. Consider the following definition:
Definition (Lurie) Let $R$ be a commutative ring. A (finite) etale covering family $\{\phi_\alpha : R \to R_\alpha\}$ is a Nisnevich covering if there is a finite sequence $a_1,\ldots,a_n\in R$ such that
• $(a_1,\ldots,a_n)$ is the unit ideal in $R$
• For each $1 \leq i \leq n$ there is an index $\alpha$ and a ring homomorphism $$\psi_i : R_\alpha \to R[a_i^{-1}]/(a_1,\ldots,a_{i-1})$$ such that $\psi_i\circ \phi_\alpha:R \to R[a_i^{-1}]/(a_1,\ldots,a_{i-1})$ is the canonical map to the quotient of the localisation.
When interpreted in $Aff$ the maps $\psi_i$ are just local sections of the etale maps $Spec R_\alpha \to Spec R$, for a given notion of 'local'.
What should the extension to non-affine schemes be?
My guess is that we just ask for an affine cover an then a Nisnevich cover of each affine, but I'm not sure of the subtleties.
I suspect we should be able to combine the maps $\psi_i$ into a single map
$$\coprod_i Spec R[a_i^{-1}]/(a_1,\ldots,a_{i-1}) \to \coprod_\alpha Spec R_\alpha,$$
which is a 'local' section of $\coprod_\alpha Spec R_\alpha \to Spec R$.
Can we describe the Nisnevich topology on schemes as being just etale covers which admit local sections over another sort of cover?
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A key feature of the Nisnevich topology is that as a cd-structure (cf. [Voevodsky, Homotopy theory of simplicial sheaves in completely decomposable topologies]) it is complete and regular. This implies what Lurie calls Nisnevich excision in DAG XI. The proof of this "excision" relies on the existence of a "splitting sequence" (cf. [Morel-Voevodsky, A^1-Homotopy Theory of Schemes, Lemma 3.1.5]) for any given Nisnevich covering.
Def.:(MV) A splitting sequence for a covering family $\{p_{\alpha}:Spec(R_\alpha)\to Spec(R)\}$ is a sequence of closed subsets of $Spec(R)$ of the form $$\emptyset = Z_{n+1}\subset Z_n\subset \ldots \subset Z_0=Spec(R)$$ such that for $i=0,\ldots,n$ the morphism $\coprod_\alpha (p_\alpha)^{-1}(Z_i\setminus Z_{i+1})\to Z_i\setminus Z_{i+1}$ splits.
This existence statement needs the space which is covered to be noetherian. Lurie drops the noetherian requirement and pays for the splitting sequence, which doesn't come for free any longer. You find the non-affine situation in section 3.1 of the Morel-Voevodsky paper.
However, here we have $Z_i:=V(a_1,\ldots,a_{i-1})$ and the first condition above says that $Z_{n+1}= \emptyset$ and the second condition gives a splitting on
$$Z_i\setminus Z_{i+1}= V(a_1,\ldots,a_{i-1})\cap (V(a_1,\ldots,a_i))^c$$ $$= V(a_1,\ldots,a_{i-1})\cap (V(a_1,\ldots,a_{i-1})\cap V(a_i))^c$$ $$= V(a_1,\ldots,a_{i-1})\cap (V(a_1,\ldots,a_{i-1})^c\cup D(a_i))$$ $$= V(a_1,\ldots,a_{i-1})\cap D(a_i)$$ $$= Spec(R[a_i^{-1}]/(a_1,\ldots,a_{i-1}))$$
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I'm not interested in the non-Noetherian situation per se, just Lurie's formulation of the definition. – David Roberts Oct 18 '11 at 19:41
I'm not sure what you intend to trigger with that comment, so just made some things more explicit. – user2146 Oct 19 '11 at 9:39
In that I don't really care about Nisnevich excision, or problems of what the definition does or does not imply for non-Noetherian schemes. I asked how to extend the definition given by Lurie to non-affine schemes, and if this definition can be condensed. – David Roberts Oct 19 '11 at 21:50
David, the purpose of archiving system of question/answers in MO is not only to satisfy the guy who asked but to have canonical balanced answers to most readers. Nisnevich excision is quite central in this business (hence important for many future users of MO answers) and I find your comments in this line at least superfluous. If you want some other aspect still to be added then say precisely what is still missing from the answers, rather than attacking part of the genuine content which you "do not really care". – Zoran Skoda Oct 21 '11 at 11:17
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# Algebraic reduction of systems on two- and three-dimensional spheres
2008, Vol. 4, No. 4, pp. 407-416
Author(s): Borisov A. V., Mamaev I. S., Ramodanov S. M.
The paper develops further the algebraic-reduction method for $SO(4)$-symmetric systems on the three-dimensional sphere. Canonical variables for the reduced system are constructed both on two-dimensional and three-dimensional spheres. The method is illustrated by applying it to the two-body problem on a sphere (the bodies are assumed to interact with a potential that depends only on the geodesic distance between them) and the three-vortex problem on a two-dimensional sphere.
Keywords: Poisson structure, Lie algebra, subalgebra, Andoyer variables
Citation: Borisov A. V., Mamaev I. S., Ramodanov S. M., Algebraic reduction of systems on two- and three-dimensional spheres, Rus. J. Nonlin. Dyn., 2008, Vol. 4, No. 4, pp. 407-416
DOI:10.20537/nd0804002
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# Math Help - Show that unit sphere in R3 is closed
1. ## Show that the unit sphere in R3 is closed
EDIT: I've posted this in the wrong part of the forum, please ignore this question.
Hi, my question is:
Show that the unit sphere with center 0 in R3, namely the set S2 :={x in R3 : (x1)^2+(x2)^2+(x3)^2=1} is closed in R3.
What I've done so far is say that to prove it's closed, I need to show that the complement of S2, XS2, is open, so:
XS2 :={x in R3 : (x1)^2+(x2)^2+(x3)^2 is not equal to 1}. I then stated the definition of an open set:
X`S2 is open if for all x in S2 there exists r>0 such that B(x, r) is a subset of S2, B(x, r)={y : d(x, y)<r}.
What I'm stuck on in this question is the choice of r, and how to show that, for any y in B(x,r), y is in S2.
Any help would be appreciated
2. ## Re: Show that unit sphere in R3 is closed
Oh dear, sorry I didn't the see the pre-university part, please ignore this post! I'll post it in the university section now.
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# How to find out where a public company spends money? [on hold]
Occasionally I will see articles about how Company X spends x dollars on A, and Company Y spends y dollars on B.
Here is an example form today: Apple spends more than \$30 million on Amazon’s cloud every month
Where does this data come from? Where does it get disclosed? Suppose I wanted to learn more about how a public company spends its money. Where can I do so? The financial reports I read from companies just show amounts and categories but not vendor names.
## put on hold as off-topic by AdB, LocalVolatility, Lliane, Bob Jansen♦2 days ago
• This question does not appear to be about quantitative finance within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.
• “according to people familiar with the arrangement” is usually a good hint that this is “internal only” information that someone chose to disclose when they probably shouldn’t have. Otherwise, this would be available in public filings such as 10Q. – Helin Apr 23 at 3:36
• I'm voting to close this question as off-topic because it is not related to quantitative finance. – AdB Apr 30 at 8:39
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Define Regions Among Overlaps
DefineRegions(overlaps.all, sample = NULL, regions = NULL)
## Arguments
overlaps.all Output from VennPeaks with return.overlaps.all set to TRUE provides matrix with columns Sample, PeakID, and matrix of intersections Primary sample of interest, used as the reference; must match one of the column names from overlaps.all vector of present/absent for columns, e.g. for 3 cols: assuming first column is passed as sample parameter: c(0, 1, 1) = three-way intersection (your sample is set to 0 in matrix) c(0, 1, 0) = two-way intersection with your sample + column 2 c(0, 0, 0) = unique to your sample This returns only the STRICT intersection (does not consider all cases); so to get all relevant peakIDs you may need to do several DefineRegions runs
## Value
PeakID for your reference sample of given overlaps, as denoted by regions
## Examples
## Run VennPeaks to retrieve overlaps.all matrix
vpo.t <- VennPeaks(rp.e, return.overlaps.all = TRUE)
## returns three-way intersect assuming column 1 is k27ac.TE
DefineRegions(vpo.t, "k27ac.TE", c(0, 1, 1))
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# My Stock Selection Process
Engineers love processes. They see processes everywhere.
As an engineer myself, I’m no different. So, for a while, I wondered if I could reduce my stock selection techniques to a process.
Well, I think I’ve managed to do it.
You will thus find below my stock selection process:
1) Pick a dividend stock you are interested in
2) Collect 10 years of dividend data (e.g. on morningstar.com)
3) Calculate the compound dividend growth rate over the last 10 years
4) Determine if the compound dividend growth rate is sustainable (e.g. with respect to earning growth and payout ratio)
4.1) If the compound dividend growth rate appears sustainable, keep the calculated rate
4.2) Otherwise, adjust the rate to a sustainable rate (e.g. the earning growth rate)
5) Determine a safety factor by which you will reduce the compound dividend growth rate (adjusted if necessary) (e.g. 20% to 40%)
6) Determine a discount rate
7) Calculate the present value of the dividends to be paid over the next 20 years using the current dividend rate, the compound dividend growth rate (adjusted if necessary) reduced by the safety factor, and the discount rate
8) Compare the calculated present value with the current price of the stock you are interested in
8.1) If the calculated present value is larger than the current price of the stock, you should consider buying the stock.
8.2) Otherwise, if the calculated present value is smaller than the current price of the stock, you should refrain from buying the stock
Now you have it.
The process described above is the process I use to determine if a dividend stock I’m interested in is worth buying.
However, I don’t buy all the dividend stocks that appear to be worth buying. There are several reasons for that, some more objective (e.g. portfolio allocation, etc.), some more subjective (e.g. risk, etc.).
Obviously, there is a lot more to be said, particularly about the hows and the whys of each step.
My process is not perfect, far from it. But by putting it in writing, I get two important benefits.
First, I get to see where I stand now and where I can improve. Second, and more importantly, I get to share it with you.
Not only can you use such a stock selection process if you think it makes sense, but now, you can also contribute to improve it.
Now that you know my stock selection process, what’s yours?
# Why I Smile When the Market Drops
Most investors are happy when the market rises. It means that the stocks they own are more valuable and that they could sell them at a profit.
Well, if you’re like me, you don’t smile when the market rises. As a matter of fact, you’re probably even a bit sad.
But why? Why would I be sad when the market rises? A rising market should be fun no?
Well the reason is pretty simple. When the market rises, the stocks I wish to purchase become more expensive. In turn, if the stocks I wish to purchase are more expensive, I have to pay more for the same dividend streams. And this why a falling stock market is the best friend of dividend investors.
But how exactly a rising or falling share price affect the yield of a stock?
## What Is Yield?
To begin with, we need to understand what is yield.
Yield is one of most important metrics for dividend investors and yet one of the simplest.
Yield is simply the annualized dividend rate (DR) divided by the share price (SP).
$Yield&space;=&space;\frac{Dividend\;&space;Rate}{Share&space;\;&space;Price}$The dividend rate is generally calculated by multiplying the next monthly or quarterly dividend by 12 or 4 respectively.
Understandably, the dividend rate does not change very often. In fact, the dividend rate only changes when the company changes it.
## How the Share Price Affects the Yield?
Given that the dividend rate does not change often, yield is mainly affected by the change in share price.
For instance, if one day the share price is SP1, the yield will be Yield1.
$Yield_{1}&space;=&space;\frac{DR}{SP_{1}}$If the next day the share price changes to SP2, the new yield will be Yield2.
$Yield_{2}&space;=&space;\frac{DR}{SP_{2}}$But how does the change in the share price affect the yield? To find out, we need to do some maths.
First, if we play with the two previous equations, we find that:
But, when you think about it, the second share price (SP2) is equal to the first share price (SP1) plus (or minus) a price variation (PV) of the first share price (SP1). So, we now have:
$SP_{2}&space;=&space;SP_{1}\cdot&space;\left&space;(&space;1&space;+&space;PV&space;\right&space;)$If we combine the last two equations and then simplify them, we get:
$Yield_{2}&space;=&space;\frac{Yield_{1}}{1+PV}$Again, as for the second share price (SP2), Yield2 is equal Yield1 plus or minus a yield variation (YV) of Yield1. That gives us:
$Yield_{2}&space;=&space;Yield_{1}\cdot&space;\left&space;(&space;1+YV&space;\right&space;)$Now, if we combine and simplify the last two equations, we get the relation between the share price variation (PV) and the yield variation (YV).
Still with me?
## Application
Now that we have the relation between the share price variation and the yield variation, we can understand how a rising or falling share price will affect the yield of a stock.
Since a picture is worth a thousand words, I have plotted the above equation for various share price variations in percentage.
Right from the start, we can notice that the more the share price drops, the more the yield rises. Conversely, the more the share price rises, the more the yield drops. There is nothing really new here. Intuitively, any dividend investor knows that. If you pay more for a stock, you get less dividends for your money.
However, and this is where it’s more interesting, the relation between the variation in share price and the variation in yield is not linear.
For instance, a 10% drop in share price will increase the yield by 11.11%. However, a 10% increase in share price will lower the yield by only 9.09%. Still, though the relation is not linear, particularly for larger variations, it remains that, as a rule of thumb, for share price variation between minus 10% to plus 10%, the yield will increase or drop at about the same rate.
## Conclusion
So, why I smile when the market drops?
Because:
When the share price drops by about one percent,
the yield rises by about one percent.
But more simply, because I get more dividends for my money.
# The Impact of Contribution Timing
A couple of weeks ago, I presented the four forces that shape a dividend portfolio. Quickly, the four forces are:
1. The contribution rate
2. The dividend yield
3. The dividend growth rate
4. The contribution growth rate
Of these four forces, the most important one is without a doubt the contribution rate, that is the amount of fresh money you can add to your portfolio each year. The reason is simple:
Without contributed money, you cannot buy dividend stocks.
You can be the best stock picker in the world, you can have found the best dividend stocks, if you cannot buy them, you won’t make any money.
Though the contribution rate is ultimately the most important force, there is another factor that must be taken into consideration. TIME.
In that sense, several readers rightly pointed out that I had left out time as one of the forces. The main reason why I left it out is that it is not a force over which you have much control. Time just exists.
Well, I think my readers were right. Thinking about it, one thing you can control with respect to time is how much you have of it before you retire (or need the money). For instance, if you start investing at 25 years old and plan to stop working at 55, then you have 30 years during which you can actively contribute.
Understandably, the more time you have, the better since your money will compound over more time. But there is a catch! As I mentioned in my previous post (here), since not all your contributions will compound for the same amount of time, the earlier contributions will have more impact than the later contributions.
## Four Scenarios
To see how the timing at which you make your contributions can affect your final portfolio, I have tested 4 scenarios in which the timing of the contributions varies. To keep it simple, in all the scenarios, the portfolio is built over 30 years and the total amount of contributed money is $300k. Also, in all the scenarios, the purchased stocks all yield 3% and the dividend growth rate is always 7%. The 4 scenarios are as follows: Scenario 1:$300k are contributed at year 1 (no other contribution afterward)
Scenario 2: $20k are contributed each year for the first 10 years, and then$5k are contributed each year for the remaining 20 years
Scenario 3: 15$k are contributed each year for the first 10 years,$5k are contributed each year for the next 10 years, and $10k are contributed each year for the last 10 years Scenario 4:$10k are contributed each year for the full 30 years.
## Results and Analysis
For each of the 4 scenarios, I have calculated two things: the portfolio base value, and the annual dividends received.
The evolution of the base value of each portfolio is presented below.
The line in red is the most extreme scenario, the whole $300k is contributed at year 1. Though such a scenario is rarely possible (unless you inherit or win the lottery), it still shows the power of early contributions. The other two lines of interest are the green and blue lines. The green line corresponds to the fourth scenario in which$10k is contributed each year for the full 30 years. The blue line corresponds to the third scenario in which $15k are contributed each year for the first 10 years and then$5k for years 11 to 20. In other words, between scenarios 3 and 4, the only difference is $50k which are contributed earlier in scenario 3. Well, looking at the results, simply by contributing that$50k earlier, you’ll get an additional $100k of portfolio value. Remember that in scenario 3, there are no more contributions than in scenario 4, only the distribution of the contributions over the 30 years is different. But more interesting is the impact on the annual dividends which results are shown below. Indeed, what strikes me the most in this graph is the difference shifting$50k from years 11 to 20 to years 1 to 10 can make on your annual dividends.
Simply by contributing $5k more each year during the first 10 years, and then contributing$5k less during the following 10 years, your annual dividends will be almost \$10k larger 30 years down the road.
This is really the power of compounding at work.
In my view, this clearly shows that, total contribution being equal, it is much preferable to make higher contributions during the early years, even if it means making smaller contribution later on.
More practically, it means that if you can put more money aside before your life really becomes expensive (cars, house, kids anyone?), do it! You will (eventually) see the difference.
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# nLab octonionic Hopf fibration
Contents
### Context
#### Bundles
bundles
fiber bundles in physics
## Constructions
#### Homotopy theory
Under construction
# Contents
## Idea
The octonionic Hopf fibration is the fibration
$\array{ S^7 &\hookrightarrow& S^15 \\ && \downarrow^{\mathrlap{p_{\mathbb{O}}}} \\ && S^8 }$
of the 15-sphere over the 8-sphere with fiber the 7-sphere. This may be derived by the Hopf construction on the 7-sphere $S^7$ with its Moufang loop structure.
Alternatively, we may construct a fibration by first decomposing $\mathbb{O}^2$ into the octonionic lines,
$l_m \coloneqq \{(x, m x)|x \in \mathbb{O}\}$ and $l_{\infty} := \{(0, y)|y \in \mathbb{O}\}$.
In this way the fibration $\mathbb{O}^2 \setminus (0, 0) \to S^8 = \{m \in \mathbb{O}\} \union \{\infty\}$ is obtained, with fibers $\mathbb{O} \setminus 0$, and the intersection with the unit sphere $S^{15} \subset \mathbb{O}^2$ provides the octonionic Hopf fibration (see OPPV 12, p. 7).
This second construction yields the standard parameterization of the octonionic Hopf fibration via $(x,y) \mapsto x y^{-1}$ (in one chart) and $(x,y ) \mapsto x^{-1} y$ (in the other), while the Hopf construction gives $(x,y) \mapsto x y$. The latter yields the generator $-1$ of $\pi_{15}(S^8) \cong \mathbb{Z}$, while the former yields $+1$.
## Properties
### $G_2$- and $Spin(9)$-equivariance
The automorphism group G2 of the octonions, as a normed algebra, manifestly acts on the octonionic Hopf fibration, such that the latter is equivariant.
But the octonionic Hopf fibration is equivariant even with respect to the Spin(9)-action, the one on $S^8 = S(\mathbb{R}^9)$ induced from the canonical action of $Spin(9)$ on $\mathbb{R}^9$, and on $S^{15} = S(\mathbb{R}^{16})$ induced from the canonical inclusion $Spin(9) \hookrightarrow Spin(16)$.
This equivariance is made fully manifest by realizing the octonionic Hopf fibration as a map of coset spaces as follows (Ornea-Parton-Piccinni-Vuletescu 12, p. 7):
$\array{ S^7 &\overset{fib(h_{\mathbb{O}})}{\longrightarrow}& S^{15} &\overset{h_{\mathbb{O}}}{\longrightarrow}& S^8 \\ = && = && = \\ \frac{Spin(8)}{Spin(7)} &\longrightarrow& \frac{Spin(9)}{Spin(7)} &\longrightarrow& \frac{Spin(9)}{Spin(8)} }$
## References
Discussion in parameterized homotopy theory is in
• A. L. Cook, M.C. Crabb, Fiberwise Hopf structures on sphere bundles, J. London Math. Soc. (2) 48 (1993) 365-384 (pdf)
• Kouyemon Iriye, Equivariant Hopf structures on a sphere, J. Math. Kyoto Univ. Volume 35, Number 3 (1995), 403-412 (Euclid)
Last revised on December 10, 2020 at 20:52:24. See the history of this page for a list of all contributions to it.
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The two most disruptive political events of the last few years are undoubtedly the Brexit referendum to leave the European Union and the election of Donald Trump. Both are commonly associated with the political consulting firm Cambridge Analytica and a technique known as Microtargeting.
If you want to understand the data science behind the Cambridge Analytica/Facebook data scandal and Microtargeting (i.e. LASSO regression) by building a toy example in R read on!
The following post is mainly based on the excellent case study “Cambridge Analytica: Rise and Fall” by my colleague Professor Oliver Gassmann (who was so kind as to email it to me) and Raphael Boemelburg, both from the University of St. Gallen, Switzerland (where I did my PhD), and “Weapons of Micro Destruction: How Our ‘Likes’ Hijacked Democracy” by Data Scientist Dave Smith (the data for the toy example is also from that article).
Also well worth a watch is the Netflix documentary “The Great Hack”. I encourage all of my colleagues from academia and all teachers to consider screening it to their students/pupils. Not many know that Netflix is kind enough to provide a license to do this legally: Neflix grant of permission for educational screenings. In this documentary, it becomes clear that microtargeting can be considered as some form of psychological warfare and information warfare, i.e. as a military-grade weapon with the potential to destroy our democratic system:
So, how does it actually work?
Basically, Microtargeting is the prediction of psychological profiles on the basis of social media activity and using that knowledge to address different personality types with customized ads. Microtargeting is not only used in the political arena but of course also in Marketing and Customer Relationship Management (CRM).
A well-known psychological model is the so-called OCEAN model:
The five personality traits are:
• Openness to experience (inventive/curious vs. consistent/cautious)
• Conscientiousness (efficient/organized vs. easy-going/careless)
• Extraversion (outgoing/energetic vs. solitary/reserved)
• Agreeableness (friendly/compassionate vs. challenging/detached)
• Neuroticism (sensitive/nervous vs. secure/confident)
You can find out about your own personality by taking this free, anonymous test: The Big Five Project Personality Test.
If you had the psychological profiles of many individuals you could use this together with modern advertising technology (which lets you show different ads to different people) to cater to their individual needs with the aim to manipulate them very efficiently:
So far, so standard… the difficult part is predicting psychological traits with high accuracy! And here comes data science into play, namely a technique called LASSO regression (for Least Absolute Shrinkage and Selection Operator), or simply the LASSO.
If you are not familiar with Classical Linear Regression (CLR) please read my post Learning Data Science: Modelling Basics first. The difference between CLR and the LASSO is that with the latter you simultaneously minimize the error of the regression and the sum of the coefficients so that some coefficients will become zero. Thereby you only retain the important variables, so LASSO regression provides automatic variable selection! The other effect is that by effectively reducing the complexity of the model (also called shrinkage in this context, some form of regularization) you prevent overfitting.
Mathematically you minimize the following expression:
The first summand is the error term of classical linear regression (the difference between the real values and the predicted values), the second is the regularization term. (lambda) is a hyperparameter which controls how big the shrinkage of the coefficients get (the bigger the smaller the coefficients).
Enough of the theory, let’s get to a toy example! We use the psychological factor “Openness” as the trait to predict. We have seven individuals with their openness score and their individual likes on certain Facebook posts (you can find the data for this example here: cambridge-analytica.csv). We use five for the training set and two for the test set:
data <- read.csv("data/cambridge-analytica.csv")
data
## Openness Person The_Colbert_Report TED George_Takei Meditation
## 1 1.85 Adam 1 1 1 1
## 2 1.60 Bob 1 1 1 1
## 3 -0.26 Cathy 0 1 1 0
## 4 -2.00 Donald 0 1 0 0
## 5 -2.50 Erin 0 0 0 0
## 6 1.77 Hilary 1 1 1 1
## 7 -2.20 Mike 0 0 0 0
## Bass_Pro_Shops NFL_Network The_Bachelor
## 1 0 0 0
## 2 0 0 0
## 3 0 0 1
## 4 1 1 0
## 5 1 1 1
## 6 0 0 0
## 7 1 1 0
## Ok_If_we_get_caught_heres_the_story
## 1 0
## 2 1
## 3 1
## 4 1
## 5 1
## 6 1
## 7 1
x_train <- as.matrix(data[1:5, 3:10])
x_test <- as.matrix(data[6:7, 3:10])
y_train <- as.matrix(data[1:5, 1])
y_test <- as.matrix(data[6:7, 1])
Now we build the actual model with the excellent glmnet package (on CRAN), which has been co-developed by one of the discoverers of the LASSO, my colleague Professor Robert Tibshirani from Standford University, and after that plot how the coefficients get smaller the bigger gets:
library(glmnet)
## Loaded glmnet 2.0-18
LASSO <- glmnet(x_train, y_train, alpha = 1) # alpha = 1 for LASSO regression
plot(LASSO, xvar = "lambda")
legend("bottomright", lwd = 1, col = 1:6, legend = colnames(x_train), cex = .7)
In the plot, you can see how growing lets the coefficients shrink. To find a good value for we use a technique called cross-validation. What it basically does is building a lot of different training- and test-sets automatically and averaging the error over all of them for different values of . After that, we plot the resulting errors with upper and lower standard-deviations:
cv_LASSO <- cv.glmnet(x_train, y_train)
## Warning: Option grouped=FALSE enforced in cv.glmnet, since < 3 observations
## per fold
plot(cv_LASSO)
In this case, we see that the minimal gives the smallest error, so we choose it for the prediction of the openness score of our test set:
round(predict(LASSO, x_test, s = cv_LASSO$lambda.min), 2) ## 1 ## 6 1.58 ## 7 -2.41 y_test ## [,1] ## [1,] 1.77 ## [2,] -2.20 Not too bad! In reality, with only 70 likes the algorithm can assess personality better than a friend of the person would be able to, with 150 likes it is better than the parents, and with 300 likes, it is even better than the spouse! Creepy, isn’t it! Another big advantage is the interpretability of LASSO regression. It is easily discernible that “The Colbert Report” and “George Takei” (a former Star Trek actor who became a gay rights and left-leaning political activist) are the biggest drivers here: round(coef(LASSO, s = cv_LASSO$lambda.min), 2)
## 9 x 1 sparse Matrix of class "dgCMatrix"
## 1
## (Intercept) -2.23
## The_Colbert_Report 1.84
## TED 0.43
## George_Takei 1.72
## Meditation 0.00
## Bass_Pro_Shops .
## NFL_Network .
## The_Bachelor .
## Ok_If_we_get_caught_heres_the_story -0.18
It is no overstatement to say that with those new possibilities of microtargeting we have entered a new era of potential (and real!) manipulation. I hope that you now understand the data science behind it better.
In my opinion that knowledge is important to be part of the necessary conversation about the consequences for our society. This conversation has only just begun… looking forward to your comments on this topic!
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|
# Bullet points and curly braces - Beamer
A few months ago, I asked for help with formatting curly braces next to bullet points, which worked very well.
However, I have tried to take that code and use it in beamer, which is unfortunately telling me it doesn't recognise the \dimexpr command, and so I'm having some trouble.
The code I am using is in the link below, can anyone advise me on how to achieve this or something similar in beamer?
Bullet points and curly braces
Thank you
The following work for me. Do I miss anything?
\documentclass{beamer}
\usepackage{amsmath}
\begin{document}
\begin{frame}
\begin{itemize}
\item Riemann Sum
\item
Trapezoidal Rule
\item
Simpson's 1/3 Rule
$\smash{\left.\rule{0pt}{.5\dimexpr3\baselineskip+2\itemsep+2\parskip}\right\} \text{\parbox{2in}{Newton Cotes formulae of different degrees}}}$
\item
Simpson's 3/8 Rule
\end{itemize}
\end{frame}
\end{document}
BTW beamer doesn't have any hatred for \dimexpr FYI.
|
# Definition of accuracy of measurement of parameters of drilling on sensitivity of indicators of process
Authors:
Abstract:
The Built system of the equations to value controlling parameter of the process of the boring, which allow to define the influence of each parameter on factors of the process - a velocity of the boring, boring metres and cost of the boring. The Certain requirements to accuracy of the measurement parameter, providing validity given for governing.
|
# center ctable wider than textwidth on page
I have a ctable which is wider than textwidth and I would like to center it on the page. I tried the solutions from here but none of them seems to work for a ctable. Here is what I tried so far
\documentclass[11pt,a4paper]{article}
\usepackage[top=50mm,bottom=25mm,left=20mm,right=15mm]{geometry}
\usepackage{ctable}
\begin{document}
%\centerline{
%\makebox[\textwidth][c]{
\noindent\ctable[]{llll}{}{
\toprule
long, long, long, long text & long, long, long, long text & long, long, long, long text & long, long, long, long text \\
long, long, long, long text & long, long, long, long text & long, long, long, long text & long, long, long, long text \\
\bottomrule
}
%}
\centerline{
\noindent\begin{tabular}{llll}
\toprule
long, long, long, long text & long, long, long, long text & long, long, long, long text & long, long, long, long text \\
long, long, long, long text & long, long, long, long text & long, long, long, long text & long, long, long, long text \\
\bottomrule
\end{tabular}}
\end{document}
As soon as I remove one of the comments in the first table I get an error "not in outer par mode" whereas the second table looks like expected.
How can I center also the first table?
Many thanks.
• \ctable adds a complete float around your table, so you can't. Use the second approach. – Skillmon Dec 8 '18 at 17:48
The documentation explains you have the doinside=\hspace*{some negative length} to solve this problem:
\documentclass[11pt,a4paper]{article}
\usepackage[top=50mm, bottom=25mm, left=20mm, right=15mm, showframe]{geometry}
\usepackage{ctable}
\usepackage{changepage}
\begin{document}
\ctable[doinside = \hspace*{-7mm}]{llll}{}{
\toprule
long, long, long, long text & long, long, long, long text & long, long, long, long text & long, long, long, long text \\
long, long, long, long text & long, long, long, long text & long, long, long, long text & long, long, long, long text \\
\bottomrule
}
\centerline{
\noindent\begin{tabular}{llll}
\toprule
long, long, long, long text & long, long, long, long text & long, long, long, long text & long, long, long, long text \\
long, long, long, long text & long, long, long, long text & long, long, long, long text & long, long, long, long text \\
\bottomrule
\end{tabular}}
\end{document}
|
Browse Questions
# Identify the product
A major is
d) None of the above
Hence (b) is the correct answer.
|
# Help for the proof of Lemma for pull-backs
I am learning category theory from the book by Steve Awodey, trying to complete all the proofs, and I got stuck at one.
Lemma: Given the diagram above, if the square at the right and the rectangles are pull-back diagrams, then so is the square at the left.
In the book, Awodey says that the proof is done by "diagram chase", but I encounter a difficulty.
My progress: Here is where I got so far.
Suppose there is a diagram $A \leftarrow_{\pi_1} X \rightarrow_{\pi_2} E$ such that $f\pi_1 = h'\pi_2$. To show that the left square is a pull back you need to show that there exists a unique morphism $u:X\rightarrow D$ such that $h''u = \pi_1$ and $f'u =\pi_2$.
Using the pull-back property of $D$ in the rectangle, you infer that there exists a unique morphism $x:X\rightarrow D$ such that $h''x =\pi_1$ and $g'f'x = g'\pi_2$. So $x$ looks like a good candidate.
Bearing this in mind, you use the pull-back property of $E$ in the right square to show that $\pi_2$ is the unique morphism $X \rightarrow E$ such that $h' \pi_2 = f \pi_1$.
Now, assuming that $fh''=h'f'$ , you can show \begin{equation*} h'(f'x) = fh''x = f\pi_1 \end{equation*}
and thus $f'x = \pi_2$.
This would complete the proof, but I cannot prove the highlighted assumption.
So the proof is, up to now, mostly diagram chase, but I cannot get that commutation down. Do I need to assume the square is commutative, or is there a way to infer it from the given assumptions?
• Also, if you can recommend en passant a text with a (little) more conceptual discussions but comparable depth as Awodey's, please do so! – Andrea May 7 '15 at 22:22
• I assume you mean $fh'' = h'f'$. It's common to require diagrams to be commutative, so I'd say you can just take this as one of the givens. – aes May 7 '15 at 23:10
• Thanks @aes, that's what I meant. – Andrea May 8 '15 at 9:31
|
## Elementary Algebra
$-6°F$
If the temperature will drop $13°$ by 6 AM and is $7°$ currently, it will be $13$ less than $7$ at 6 AM. $7-13=7+(-13)=-6$. The temperature at 6 AM will be $-6°F$
|
# Fuzzing: Breaking Things with Random Inputs¶
In this chapter, we'll start with one of the simplest test generation techniques. The key idea of random text generation, also known as fuzzing, is to feed a string of random characters into a program in the hope to uncover failures.
Now, we explicitly import (and thus require) the earlier chapter.
## A Testing Assignment¶
Fuzzing was born in a "dark and stormy night in the Fall of 1988" \cite{Takanen2008}. Sitting in his apartment in Wisconsin, Madison, professor Barton Miller was connected to his university computer via a 1200 baud telephone line. The thunderstorm caused noise on the line, and this noise in turn caused the UNIX commands on either end to get bad inputs – and crash. The frequent crashes surprised him – surely, programs should be more robust than that? As a scientist, he wanted to investigate the extent of the problem and its causes. So he crafted a programming exercise for his students at the University of Wisconsin-Madison – an exercise that would have his students create the first fuzzers.
This is how the assignment read:
The goal of this project is to evaluate the robustness of various UNIX utility programs, given an unpredictable input stream. [...] First, you will build a fuzz generator. This is a program that will output a random character stream. Second, you will take the fuzz generator and use it to attack as many UNIX utilities as possible, with the goal of trying to break them.
This assignment captures the essence of fuzzing: Create random inputs, and see if they break things. Just let it run long enough and you'll see.
## A Simple Fuzzer¶
Let us try to fulfill this assignment and build a fuzz generator. The idea is to produce random characters, adding them to a buffer string variable (out), and finally returning the string.
This implementation uses the following Python features and functions:
• random.randrange(start, end) – return a random number $[$ start, end $)$
• range(start, end) – create a list with integers in the range $[$ start, end $)$. Typically used in iterations.
• for elem in list: body – execute body in a loop with elem taking each value from list.
• for i in range(start, end): body – execute body in a loop with i from start to end $-$ 1.
• chr(n) – return a character with ASCII code n
In [4]:
def fuzzer(max_length=100, char_start=32, char_range=32):
"""A string of up to max_length characters
in the range [char_start, char_start + char_range]"""
string_length = random.randrange(0, max_length + 1)
out = ""
for i in range(0, string_length):
out += chr(random.randrange(char_start, char_start + char_range))
return out
With its default arguments, the fuzzer() function returns a string of random characters:
In [5]:
fuzzer(10000, ord('0'), 10)
Out[5]:
'05019909290472161526754662764077397238263284875006525969855170044875218715353632213398138309591718557903509563798223181333736376231806540592671117168091529597156161784284343845058970154989924320627852497480591764892914972419195191780486921945042684001643803951766460110841162451116121242733274728080464152082356527724545234224362940770498384335322881812668215827391116575601341582411623680063727093529095074291321925579213929015651424977348492258837561126523844893078164683393136320460122861066422397491307972587773076704262019156908566907904081589687312226672370744175187976027027883416357195828412857453270691183472366371238280209086373128985969840714953383135370437013538964200168396824091263299270704012609370696299059023984931669531260814850470204011534185905185455177405659597451459098358372775881800041539574681588588923551670653709350491539221311216460944281602911532021055186610397222652461785446676912500324544215150613751240933243878567119241458894132326833026600647526542237088790093425313837236312615242629802140724861940498050377946428381808203755215473081587219595906854595042312359899261371769580743913460021609271454188375258801167129567777769724999968940185332531889822702310722220667694440005771869877555043422769240585597102103541810345732047250705202327164659995103264285090931491662647433333370656931879385750235153620783916880544372258631231096476091262204940979003364874142392500737868898022574003155722968262587517291649153809351837692884043757943258158925670630214342783059235796310653596418465571504164304756015686256315560823906758542789233629367704204397139596769164216338198023865895963226283308656851634229780361891701620228800538816372834744509700018036031392344015694560409096726758535427568059379072462680963143771787788716678441121316076152145564147482242906380204424595623585858917592101403408660218337877539601664019942960936382435649132768319985427588689593136106105625709084602407295329972083227416760058358062660347529660971809721219436446754137673682253190668277388000332721153934609279139896624295314963374768922617466747984606914673553505323565943833411420254746521265627655939309458549848654944743850465869012430762339892878870976374389141881695684995845099020786240474230968612597843536755946131458217395577355630784799355305884615650502574908146901618197205209007961781349239975658707921184393204595964545079042864955039831509504109316236166782787266315519974541440456805939926347925711453159851511242543867695154627704501210046594751436935490115574082263794465770803317986686152895161451864945662214744939736480106456011060610037586451713611382617008763793575571222878375461878193130634031709794923839987113943738314767038169028561033139228958746972667370931178706751031276046881506035426165352006126943229353563662257951151194855065317089780802859972686918933311266527271109600258326793009843707733635959481900335428203661531089422757679189891839671443158785147386773757168687297125175369691526470266719063838926088565916958454683614921926580890249593784438465862846428027431079698734818828239701619343264932869969041939642970088916373952255652551355348290565022090819201773300748888487239472076716955789396439432300808009268752343083429919774496020148499089696881939279201412527887278160423681427319251145965520519910835507098801545264451821952002993963381820484956337418741365268072505027049944801267319078396515769375613858734787820026525441264403564265643456680662854535907704553110087287540684377449603514356639920491882641544631339517773892459225197660130221309115466028014020525275674384311165154864850465151630083744839456324485824824563625808608020669155613487796394748171773592741103863509607066040286037658823292568725124362280235713377346393922883536618522286603643274517798087069032867558841215854925313644220505653585425234949109748314766679036690820479799892319968992126546364675241219104343060670012218509922298387509877343854326296518452049578010632965851290705712281370223363282372459745092145991484694865751901818746165561150465449512049572174833814213042625334463217921189131113802181612217367258435703659318983141954608829316018394491180735960223765552310184005020270073872747825092836163031215543717049153392379847205981275462400409652640968962961089809352797235989507880856342229316581635914223333178321568707194840936257828100845522711962072041986128205109824545189845238654548475532261046113831746106223528910676222657257190400198641166125431731954106864044502583480011173134199167426703143627609254349235622698358899820468869302040872474590686685061411051676828712865119590817721671844719261479821293128411111326002309166887902689586898704572291286006713427343183160200668687350075098011201573738594030215155318680879044281251631546415647983284025935217791966563095517947945269623535020521229975503246354138172143041543830776648413147472991620338551819015375121907477519607164919708454459986869881483084159912521590836771744743819943195668502644468339481194074574293213480189179077685146249259439663392358563190669415002714213226841781446349394683952876009449694535716741365663265793142406241287083344610480657309317740373264369022960486745304283263925926319691336615089852851008044067538082547678960512061397645967935855253274978286650908021371440266372637929312305626645843481989396689622598013279563603702016681581852031584326165248588667022435353401349714845842638319006461871938355948752003331493650666965069397426347887673679422529687454754490049373929487075150403435552520707562711813142621014076823925614748377528986762437435109837757945560236307806763752600744810546085319489930468859026489199311005054486844429563390304409439992220729163110887400333452106244585814551208582443487788281552333064328242288047221047147981312223428651388777550502138417268395821111377313403455299443319185466554117634656543031226647347997212759045923491955790610111028823756048536015202376020178300288043903188868918996370853795923036185005065303992937197485451727926829293048158328785257286160378803323135619712165359976937272620371532540567130898806112642105880138356493202379207287271615234416392912816939381907046275533242231422859985358778465631403321179931514274129914196021640617125429053967150331120911112021736278510861083166712262800101465146822354319463548631801170932337534476555686774337538161216584011120622489017309428152231170122608714027075340245802183779333359439753115705867360456881311563134991778795554656925228203920345349050045906671796045991235086373832671573353666897019878600159352658122421065509932883606677508744307448826055558620669227109536679499329548304188448153351330746384035212176820750409208952904850556962596813270036285844764623217941483523501264540457971398608725989093790202821683164305478735309956362083013422831882453810455545705641496709954196737450774574891895264013504560330487447054289153367752502448381352000528473628974226795849777475922322924920341950793707561510901789304013747650459546819932602241376103203517074481991520971989088208045413629203608460784402418636769227644311833673495815931683874195908578234010676066428246115897419668897939891744887442219804638845539242226589070279941958770794739125828432840241807902286183801735488146557624584576041596458339005613309715913582725751302218702519627335761852006340757427297382513769004223076278584135328960646127124752026205702562687311568617701797321079281080493647957050176978316165227438564154560318008611409631549449394582736341641291649894016511867094552477775726745021624564515918767538475659326942857403813772568298639195645561255825092159406009802619704811821720462987460577589178476081322201613697886270107475162776625546595111215724241846876148410854104497211948477383107710969073621863383165094343809244300885412957191854087326835815668542774822223099485624711444579468554504470817312869430793447826273719843908662112687024118346684741597614418973687289673045724217660509497442911741712780069472926622964460549300995643832458004824657766115008206577413392522716411267494074411311777828307974393244078920927009895835401132493497145948531998007555079820428552763708130165950371894377183105619163112871842942570986188002278849485182012395338231176980569083045720826565145223589675463241076286451667807309229184138129328431808449871386448292819326039144425632806550609530218459483384589248073890148452204077239822612769208872282179999105162278200321223899057245225137841233083237536279091927478422294685313472309561162501872837393277441029600514885941384099704979810250552482451293016439782842856914015607695549149926556956117706169076071313118348225920924215134767598550961544825538315476299444653088701109597845957054253311230672179638717002059995644506944672597175566574616003164014660122484220111000305684056984392269513706217731418213089505100343073439674319933497169460907616735560685375902246356077645955959234830707061423319075086993704611905660412455170549849704381622349314903930389492564418736041591365405985336172240465229994862412390670079501305034487793948243837069884516157994714478994749496080935686981353550466469309133828608398285268748693953836706464167497195410345646906759986445732412302427114966900607849939816571591002186154751519149146751581957417406648506712959387034768070547696960050188062914780919388668231994814957934578404663966526344829220097998439943159248170254421450537223671228295062147815483696906052521056318738174287523409411395051779955107232214078972893291602543657764835235726936888527545395256937252858279977271766583347295828838712608096436607591509738764470952271691029352535253846783703897755317915940036380797058841919228792000653867085428781507722688803808866560349893430946807550366614963'
Bart Miller coined the term "fuzz" as the name for such random, unstructured data. Now imagine that this "fuzz" string was the input to a program expecting a specific input format – say, a comma-separated list of values, or an e-mail address. Would the program be able to process such an input without any problems?
If the above fuzzing input already is intriguing, consider that fuzzing can easily be set up to produce other kinds of input. For instance, we can also have fuzzer() produce a series of lowercase letters. We use ord(c) to return the ASCII code of the character c.
In [6]:
fuzzer(1000, ord('a'), 26)
Out[6]:
'xcmtcluakdmcpdkcgqkgxxknluubgfpktxjobnbuvyrxbiopixlvlvceixdsaxtboonefqnxdpvrtrjovfnjupwpjdhlbyjzmlldyfgchgugucpnzadredwdmaieygkyhjjwrnhwgceqwjmsjjbfndakrhkhgwpeeyumdbjbfligrrsmepmzbnbjxtthemibfjmgtvgixhdmhccdsbgqjrdfceklicibsqcjyyqtymtzvnntrjxqwsjrireurhopuzaapwsqygyzpnmogzcqziwbjbxbvaazrvnwuuryunouwqgygicbimiscwlnmffuxqeqxivakfnffxpaolraqhtrjfrsvgafigabxbakyytqktrr'
Assume a program expects an identifier as its input. Would it expect such a long identifier?
## Fuzzing External Programs¶
Let us see what happens if we actually invoke an external program with fuzzed inputs. To this end, let us proceed in two steps. First, we create an input file with fuzzed test data; then we feed this input file into a program of choice.
### Creating Input Files¶
Let us obtain a temporary file name such that we do not clutter the file system.
In [8]:
basename = "input.txt"
tempdir = tempfile.mkdtemp()
FILE = os.path.join(tempdir, basename)
print(FILE)
/var/folders/n2/xd9445p97rb3xh7m1dfx8_4h0006ts/T/tmpja61w7wh/input.txt
We can now open this file for writing. The Python open() function opens a file into which we can then write arbitrary contents. It is commonly used in conjunction with the with statement, which ensures that the file is closed as soon as it is no longer needed.
In [9]:
data = fuzzer()
with open(FILE, "w") as f:
f.write(data)
We can verify that the file was actually created by reading its contents:
In [10]:
contents = open(FILE).read()
print(contents)
assert(contents == data)
.24+>!+"8#/&,%?>-"%-6!9-57;*8>6=(5<)9&;?(+%;0'&-2,"; 8/.,"-2)2236.:'/&*679.6$<#?8%(+: ### Invoking External Programs¶ Now that we have an input file, we can invoke a program on it. For the fun of it, let us test the bc calculator program, which takes an arithmetic expression and evaluates it. To invoke bc, let us use the Python subprocess module. This is how this works: In [11]: import os import subprocess In [12]: program = "bc" with open(FILE, "w") as f: f.write("2 + 2\n") result = subprocess.run([program, FILE], stdin=subprocess.DEVNULL, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True) # Will be "text" in Python 3.7 From the result, we can check the program output. In the case of bc, this is the result of evaluating the arithmetic expression: In [13]: result.stdout Out[13]: '4\n' We can also check the status. A value of 0 indicates that the program terminated correctly. In [14]: result.returncode Out[14]: 0 Any error messages would be available in results.stderr: In [15]: result.stderr Out[15]: '' Instead of bc, you can actually put in any program you like. Be aware, though, that if your program is able to change or even damage your system, there is quite a risk that the fuzzed input contains data or commands that do precisely this. Just for the fun of it, imagine you would test a file removal program. What is the chance of the fuzzer producing a valid file name? (Note that . and / may be valid directory names already.) ### Long-Running Fuzzing¶ Let us now feed a large number of inputs into our tested program, to see whether it might crash on some. We store all results in the runs variable as pairs of input data and the actual result. (Note: running this may take a while.) In [16]: trials = 100 program = "bc" runs = [] for i in range(trials): data = fuzzer() with open(FILE, "w") as f: f.write(data) result = subprocess.run([program, FILE], stdin=subprocess.DEVNULL, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True) runs.append((data, result)) We can now query runs for some statistics. For instance, we can query how many runs actually passed -- that is, there were no error messages. We use a list comprehension here: The form expression for element in list if condition returns a list of evaluated expressions in which each element comes from list if the condition was true. (Actually, a list comprehension returns a list generator, but for our purposes, the generator behaves like a list.) Here, we have the expression be 1 for all elements where condition holds, and we use sum() to sum over all elements in the list. In [17]: sum(1 for (data, result) in runs if result.stderr == "") Out[17]: 6 Most inputs apparently are invalid – not a big surprise, as it is unlikely that a random input contains a valid arithmetic expression. Let us take a look at the first error message: In [18]: errors = [(data, result) for (data, result) in runs if result.stderr != ""] (first_data, first_result) = errors[0] print(repr(first_data)) print(first_result.stderr) '400$1$6= 01>"1+)/3-;4/&*$;63=#/2$-,7,>114=/"*%= 6' /var/folders/n2/xd9445p97rb3xh7m1dfx8_4h0006ts/T/tmpja61w7wh/input.txt 1: illegal character:$
/var/folders/n2/xd9445p97rb3xh7m1dfx8_4h0006ts/T/tmpja61w7wh/input.txt 1: parse error
/var/folders/n2/xd9445p97rb3xh7m1dfx8_4h0006ts/T/tmpja61w7wh/input.txt 1: illegal character: $ Are there any runs with messages other than illegal character, parse error, or syntax error? (Say, something like crash or you found a fatal bug?) Not very many: In [19]: [result.stderr for (data, result) in runs if result.stderr != "" and "illegal character" not in result.stderr and "parse error" not in result.stderr and "syntax error" not in result.stderr] Out[19]: [] Maybe a crash would be indicated by bc just crashing. Unfortunately, the return code is never nonzero: In [20]: sum(1 for (data, result) in runs if result.returncode != 0) Out[20]: 0 How about we let the above bc test run for some more? While it is running, let us take a look on how the state of the art was in 1989. ## Bugs Fuzzers Find¶ When Miller and his students ran their first fuzzers in 1989, they found an alarming result: About a third of the UNIX utilities they fuzzed had issues – they crashed, hung, or otherwise failed when confronted with fuzzing input \cite{Miller1990}. This also included the bc program, above. (Apparently, the bugs have now been fixed!) Considering that many of these UNIX utilities were used in scripts that would also process network input, this was an alarming result. Programmers quickly built and ran their own fuzzers, rushed to fix the reported errors, and learned not to trust external inputs anymore. What kind of problems did Miller's fuzzing experiment find? It turns out that the mistakes programmers made in 1990 are still the same mistakes being made today. ### Buffer Overflows¶ Many programs have built-in maximum lengths for inputs and input elements. In languages like C, it is easy to excess these lengths without the program (or the programmer) even noticing, triggering so-called buffer overflows. The following code, for instance, happily copies the input string into a weekday string even if input has more than eight characters: char weekday[9]; // 8 characters + trailing '\0' terminator strcpy (weekday, input); Ironically, this already fails if input is "Wednesday" (9 characters); any excess characters (here, 'y' and the following '\0' string terminator) are simply copied to whatever resides in memory after weekday, triggering arbitrary behavior; maybe some boolean character variable which would be set from 'n' to 'y'. With fuzzing, it is very easy to produce arbitrary long inputs and input elements. We can easily simulate this buffer overflow behavior in a Python function: In [21]: def crash_if_too_long(s): buffer = "Thursday" if len(s) > len(buffer): raise ValueError And yes, it quickly crashes. In [22]: from ExpectError import ExpectError In [23]: trials = 100 with ExpectError(): for i in range(trials): s = fuzzer() crash_if_too_long(s) Traceback (most recent call last): File "<ipython-input-23-f83db3d59a06>", line 5, in <module> crash_if_too_long(s) File "<ipython-input-21-928c2d2de976>", line 4, in crash_if_too_long raise ValueError ValueError (expected) ### Missing Error Checks¶ Many programming languages do not have exceptions, but instead have functions return special error codes in exceptional circumstances. The C function getchar(), for instance, normally returns a character from the standard input; if no input is available anymore, it returns the special value EOF (end of file). Now assume a programmer is scanning the input for the next character, reading in characters with getchar() until a space character is read: while (getchar() != ' ') { } What happens if the input ends prematurely, as would perfectly be feasible with fuzzing? Well, getchar() returns EOF, and keeps on returning EOF when called again; so the code above simply enters an infinite loop. Again, we can simulate such missing error checks. Here's a function that will effectively hang if no space is present in the input: In [24]: def hang_if_no_space(s): i = 0 while True: if i < len(s): if s[i] == ' ': break i += 1 Using the timeout mechanism from our Introduction to Testing, we can interrupt this function after some time. And yes, it does hang after a few fuzzing inputs. In [25]: from ExpectError import ExpectTimeout In [26]: trials = 100 with ExpectTimeout(2): for i in range(trials): s = fuzzer() hang_if_no_space(s) Traceback (most recent call last): File "<ipython-input-26-8e40f7d62a1b>", line 5, in <module> hang_if_no_space(s) File "<ipython-input-24-5f437edacff4>", line 7, in hang_if_no_space i += 1 File "<ipython-input-24-5f437edacff4>", line 7, in hang_if_no_space i += 1 File "<string>", line 16, in check_time TimeoutError (expected) The with ExpectTimeout() line in the above code ensures that execution of the enclosed code is interrupted after two seconds, printing the error message. ### Rogue Numbers¶ With fuzzing, it is easy to generate uncommon values in the input, causing all kinds of interesting behavior. Consider the following code, again in the C language, which first reads a buffer size from the input, and then allocates a buffer of the given size: char *read_input() { size_t size = read_buffer_size(); char *buffer = (char *)malloc(size); // fill buffer return (buffer); } What happens if size is very large, exceeding program memory? What happens if size is less than the number of characters following? What happens if size is negative? By providing a random number here, fuzzing can create all kinds of damages. Again, we can easily simulate such rogue numbers in Python. The function collapse_if_too_large() fails if the passed value (a string) is too large after having been converted to an integer. In [27]: def collapse_if_too_large(s): if int(s) > 1000: raise ValueError We can have fuzzer() create a string of digits: In [28]: long_number = fuzzer(100, ord('0'), 10) print(long_number) 6704 If we feed such numbers into collapse_if_too_large(), it will very soon fail. In [29]: with ExpectError(): collapse_if_too_large(long_number) Traceback (most recent call last): File "<ipython-input-29-7a1817f3dbfc>", line 2, in <module> collapse_if_too_large(long_number) File "<ipython-input-27-2c22a83a4dca>", line 3, in collapse_if_too_large raise ValueError ValueError (expected) If we really wanted to allocate that much memory on a system, having it quickly fail as above actually would be the better option. In reality, running out of memory may dramatically slow systems down, up to the point that they become totally unresponsive – and restarting is the only option. One might argue that these are all problems of bad programming, or of bad programming languages. But then, there are thousands of people starting to program every day, and all of them make the same mistakes again and again, even today. ## Catching Errors¶ When Miller and his students built their first fuzzer, they could identify errors simply because the program would crash or hang – two conditions that are easy to identify. If the failures are more subtle, though, we need to come up with additional checks. ### Generic Checkers¶ Buffer overflows, as discussed above, are a particular instance of a more general problem: In languages like C and C++, a program can access arbitrary parts of its memory – even those parts that are uninitialized, already freed or simply not part of the data structure you are trying to access. This is necessary if you want to write an operating system, and great if you want a maximum of performance or control, but pretty bad if you want to avoid mistakes. Fortunately, there are tools that help catching such issues at runtime, and they are great when combined with fuzzing. #### Checking Memory Accesses¶ To catch problematic memory accesses during testing, one can run C programs in special memory-checking environments; at runtime, these check for each and every memory operation whether it accesses valid and initialized memory. A popular example is LLVM Address Sanitizer which detects a whole set of potentially dangerous memory safety violations. In the following example we will compile a rather simple C program with this tool and provoke an out-of-bounds read by reading past an allocated portion of memory. In [30]: with open("program.c", "w") as f: f.write(""" #include <stdlib.h> #include <string.h> int main(int argc, char** argv) { /* Create an array with 100 bytes, initialized with 42 */ char *buf = malloc(100); memset(buf, 42, 100); /* Read the N-th element, with N being the first command-line argument */ int index = atoi(argv[1]); char val = buf[index]; /* Clean up memory so we don't leak */ free(buf); return val; } """) In [32]: print_file("program.c") #include <stdlib.h> #include <string.h> int main(int argc, char** argv) { /* Create an array with 100 bytes, initialized with 42 */ char *buf = malloc(100); memset(buf, 42, 100); /* Read the N-th element, with N being the first command-line argument */ int index = atoi(argv[1]); char val = buf[index]; /* Clean up memory so we don't leak */ free(buf); return val; } We compile this C program with address sanitization enabled: In [33]: !clang -fsanitize=address -g -o program program.c If we run the program with an argument of 99, it returns buf[99], which is 42. In [34]: !./program 99; echo$?
42
Accessing buf[110], however, results in an out-of-bounds error in AddressSanitizer.
In [35]:
!./program 110
=================================================================
==35702==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60b0000000ae at pc 0x00010bb53ea5 bp 0x7ffee40ac500 sp 0x7ffee40ac4f8
#0 0x10bb53ea4 in main program.c:12
#1 0x7fff679d3ed8 in start (libdyld.dylib:x86_64+0x16ed8)
0x60b0000000ae is located 10 bytes to the right of 100-byte region [0x60b000000040,0x60b0000000a4)
#0 0x10bbb2f53 in wrap_malloc (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x56f53)
#1 0x10bb53df4 in main program.c:7
#2 0x7fff679d3ed8 in start (libdyld.dylib:x86_64+0x16ed8)
SUMMARY: AddressSanitizer: heap-buffer-overflow program.c:12 in main
0x1c15ffffffc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1c15ffffffd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1c15ffffffe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1c15fffffff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1c1600000000: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
=>0x1c1600000010: 00 00 00 00 04[fa]fa fa fa fa fa fa fa fa fa fa
0x1c1600000020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c1600000030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c1600000040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c1600000050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c1600000060: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==35702==ABORTING
If you want to find errors in a C program, turning on such checks for fuzzing is fairly easy. It will slow down execution by a certain factor depending on the tool (for AddressSanitizer it is typically 2$\times$) and also consume more memory, but CPU cycles are dead cheap compared to the human effort it takes to find these bugs.
Out-of-bounds accesses to memory are a great security risk, as they may let attackers access or even modify information that is not meant for them. As a famous example, the HeartBleed bug was a security bug in the OpenSSL library, implementing cryptographic protocols that provide communications security over a computer network. (If you read this text in a browser, it is likely encrypted using these protocols.)
The HeartBleed bug was exploited by sending a specially crafted command to the SSL heartbeat service. A heartbeat service is used to check if the server on the other end is still alive. A client would send the service a string like
BIRD (4 letters)
to which the server would reply with BIRD, and the client would know the server is alive.
Unfortunately, this service could be exploited by asking the server to reply with more than the requested set of letters. This is very well explained in this XKCD comic:
In the OpenSSL implementation, these memory contents could involve cryptographic certificates, private keys, and more – and worse, no one would notice that this memory just had been accessed. When the HeartBleed bug was discovered, it had been around for many years, and none would know whether and which secrets had already leaked; the quickly set up HeartBleed announcement page said it all.
But how was HeartBleed discovered? Very simple. Researchers both at the Codenomicon company as well as with Google compiled the OpenSSL library with a memory sanitizer, and then happily flooded it with fuzzed commands. The memory sanitizer would then notice whether an out-of-bounds memory access had occurred – and actually, it would very quickly discover this.
A memory checker is just one of many checkers one can run to detect runtime errors during fuzzing. In the chapter on oracles, we will learn more about how to define generic checkers.
#### Information Leaks¶
Information leaks may not only occur through illegal memory accesses; they can also occur within "valid" memory – if this "valid" memory contains sensitive information that should not leak out. Let us illustrate this issue in a Python program. To start with, let us create some program memory filled with actual data and random data:
In [37]:
secrets = ("<space for reply>" + fuzzer(100)
+ "<secret-certificate>" + fuzzer(100)
+ "<secret-key>" + fuzzer(100) + "<other-secrets>")
We add more "memory" characters to secrets, filled with "deadbeef" as marker for uninitialized memory:
In [38]:
uninitialized_memory_marker = "deadbeef"
while len(secrets) < 2048:
secrets += uninitialized_memory_marker
We define a service (similar to the heartbeat service discussed above) that would take a reply to be sent back, as well as a length. It would store the reply to be sent in memory, and then send it back with the given length.
In [39]:
def heartbeat(reply, length, memory):
# Send back heartbeat
s = ""
for i in range(length):
s += memory[i]
return s
This perfectly works for standard strings:
In [40]:
heartbeat("potato", 6, memory=secrets)
Out[40]:
'potato'
In [41]:
heartbeat("bird", 4, memory=secrets)
Out[41]:
'bird'
However, if the length is greater than the length of the reply string, additional contents of memory spill out. Note that all of this still occurs within regular array bounds, so an address sanitizer would not be triggered:
In [42]:
heartbeat("hat", 500, memory=secrets)
Out[42]:
'hatace for reply>"#<secret-certificate>$#,;7"<secret-key>*89<other-secrets>deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefd' How can one detect such issues? The idea is to identify information that should not leak out, such as the given secrets, but also uninitialized memory. We can simulate such a check in a small Python example: In [44]: with ExpectError(): for i in range(10): s = heartbeat(fuzzer(), random.randint(1, 500), memory=secrets) assert not s.find(uninitialized_memory_marker) assert not s.find("secret") Traceback (most recent call last): File "<ipython-input-44-b7e8a1210599>", line 4, in <module> assert not s.find(uninitialized_memory_marker) AssertionError (expected) With such a check, we find that secrets and/or uninitialized memory indeed leak out. In the chapter on information flow, we will discuss how to do this automatically, "tainting" sensitive information and values derived from them, and ensuring that "tainted" values do not leak out. As a rule of thumb, you should always enable as many automatic checkers as possible during fuzzing. CPU cycles are cheap, and errors are expensive. If you only execute the program without an option to actually detect errors, you will be missing several opportunities. ### Program-Specific Checkers¶ Besides generic checkers that apply to all programs on a given platform or in a given language, you can also devise specific checkers that apply to your program, or a subsystem. In the chapter on testing, we already have hinted at techniques of runtime verification that check function results at runtime for correctness. One key idea for detecting errors early is the concept of assertion – a predicate that checks the input (precondition) and the result (postcondition) of important functions. The more assertions you have in your program, the higher your chances to detect errors during execution that would go undetected by generic checkers – notably during fuzzing. If you worry about the impact of assertions on performance, keep in mind that assertions can be turned off in production code (although it can be helpful to leave the most critical checks active). One of the most important uses of assertions for finding errors is checking the integrity of complex data structures. Let us illustrate the concept using a simple example. Suppose we have a mapping of airport codes to airports, as in In [45]: airport_codes = { "YVR": "Vancouver", "JFK": "New York-JFK", "CDG": "Paris-Charles de Gaulle", "CAI": "Cairo", "LED": "St. Petersburg", "PEK": "Beijing", "HND": "Tokyo-Haneda", "AKL": "Auckland" } # plus many more In [46]: airport_codes["YVR"] Out[46]: 'Vancouver' In [47]: "AKL" in airport_codes Out[47]: True This list of airport codes may be pretty critical: if we have a spelling mistake in any of the airport codes, this may impact whatever application we have. We therefore introduce a function that checks the list for consistency. The consistency condition is called a representation invariant, and functions (or methods) that check it are therefore typically named repOK() for "the representation is ok". First, let's have a checker for individual airport codes. The checker fails if the code is inconsistent. In [48]: def code_repOK(code): assert len(code) == 3, "Airport code must have three characters: " + repr(code) for c in code: assert c.isalpha(), "Non-letter in airport code: " + repr(code) assert c.isupper(), "Lowercase letter in airport code: " + repr(code) return True In [49]: assert code_repOK("SEA") We can now use code_repOK() to check all elements in the list: In [50]: def airport_codes_repOK(): for code in airport_codes: assert code_repOK(code) return True In [51]: with ExpectError(): assert airport_codes_repOK() If we add an invalid element to the list, our check would fail: In [52]: airport_codes["YMML"] = "Melbourne" In [53]: with ExpectError(): assert airport_codes_repOK() Traceback (most recent call last): File "<ipython-input-53-21eb3b08ef3e>", line 2, in <module> assert airport_codes_repOK() File "<ipython-input-50-f8128f7dc918>", line 3, in airport_codes_repOK assert code_repOK(code) File "<ipython-input-48-345123a45730>", line 2, in code_repOK assert len(code) == 3, "Airport code must have three characters: " + repr(code) AssertionError: Airport code must have three characters: 'YMML' (expected) Of course, rather than manipulating the list directly, we'd have a special function for adding elements; this could then also check whether the code is valid: In [54]: def add_new_airport(code, city): assert code_repOK(code) airport_codes[code] = city In [55]: with ExpectError(): # For BER, ExpectTimeout would be more appropriate add_new_airport("BER", "Berlin") This check also allows us to find out errors in argument lists: In [56]: with ExpectError(): add_new_airport("London-Heathrow", "LHR") Traceback (most recent call last): File "<ipython-input-56-6aeb45bf2b91>", line 2, in <module> add_new_airport("London-Heathrow", "LHR") File "<ipython-input-54-f4d30ab4bf9e>", line 2, in add_new_airport assert code_repOK(code) File "<ipython-input-48-345123a45730>", line 2, in code_repOK assert len(code) == 3, "Airport code must have three characters: " + repr(code) AssertionError: Airport code must have three characters: 'London-Heathrow' (expected) For maximum checking, though, the add_new_airport() function would also ensure the correct representation of the list of airport codes – before and after changing it. In [57]: def add_new_airport(code, city): assert code_repOK(code) assert airport_codes_repOK() airport_codes[code] = city assert airport_codes_repOK() This catches the inconsistency introduced earlier: In [58]: with ExpectError(): add_new_airport("IST", "Istanbul Yeni Havalimanı") Traceback (most recent call last): File "<ipython-input-58-a80a619d120e>", line 2, in <module> add_new_airport("IST", "Istanbul Yeni Havalimanı") File "<ipython-input-57-93da9120109e>", line 3, in add_new_airport assert airport_codes_repOK() File "<ipython-input-50-f8128f7dc918>", line 3, in airport_codes_repOK assert code_repOK(code) File "<ipython-input-48-345123a45730>", line 2, in code_repOK assert len(code) == 3, "Airport code must have three characters: " + repr(code) AssertionError: Airport code must have three characters: 'YMML' (expected) The more repOK() assertions exist in your code, the more errors you will catch – even those specific to only your domain and problem. On top, such assertions document the assumptions you made during programming and thus help other programmers to understand your code and prevent errors. As a final example, let us consider a rather complex data structure – a red-black tree, a self-balancing binary search tree. Implementing a red-black tree is not too hard, but getting it correct can be a task of several hours even for experienced programmers. A repOK() method, however, documents all the assumptions and checks them as well: In [59]: class RedBlackTree: def repOK(self): assert self.rootHasNoParent() assert self.rootIsBlack() assert self.rootNodesHaveOnlyBlackChildren() assert self.treeIsAcyclic() assert self.parentsAreConsistent() return True def rootIsBlack(self): if self.parent is None: assert self.color == BLACK return True def add_element(self, elem): assert self.repOK() # Add the element assert self.repOK() def delete_element(self, elem): assert self.repOK() # Delete the element assert self.repOK() Here, repOK() is a method that runs on an object of the RedBlackTree class. It runs five different checks, all of which have their own assertions. Whenever an element is added or deleted, all these consistency checks are run automatically. If you have an error in any of these, the checkers will find them – if you run the tree through sufficiently many fuzzed inputs, of course. ### Static Code Checkers¶ Many of the benefits from repOK() assertions can also be obtained by using static type checkers on your code. In Python, for instance, the MyPy static checker can find type errors as soon as types of arguments are properly declared: In [60]: from typing import Dict airport_codes = { "YVR": "Vancouver", # etc } # type: Dict[str, str] If we now add a key with a non-string type, as in In [61]: airport_codes[1] = "First" this would be caught by MyPy immediately: $ mypy airports.py
airports.py: error: Invalid index type "int" for "Dict[str, str]"; expected type "str"
Statically checking more advanced properties such as the airport code consisting of exactly three uppercase characters or a tree being acyclic, however, quickly reach the limits of static checking. Your repOK() assertions will still be needed – best in conjunction with a good test generator.
## A Fuzzing Architecture¶
Since we'd like to reuse some parts of this chapter in the following ones, let us define things in a way that are easier to reuse, and in particular easier to extend. To this end, we introduce a number of classes that encapsulate the functionality above in a reusable way.
### Runner Classes¶
The first thing we introduce is the notion of a Runner – that is, an object whose job it is to execute some object with a given input. A runner typically is some program or function under test, but we can also have simpler runners.
Let us start with a base class for runners. A runner essentially provides a method run(input) that is used to pass input (a string) to the runner. run() returns a pair (result, outcome). Here, result is a runner-specific value that gives details on the run; outcome is a value that classifies the result in three categories:
• Runner.PASS – the test passed. The run produced correct results.
• Runner.FAIL – the test failed. The run produced incorrect results.
• Runner.UNRESOLVED – the test neither passed nor failed. This happens if the run could not take place – for instance, because the input was invalid.
In [62]:
class Runner(object):
# Test outcomes
PASS = "PASS"
FAIL = "FAIL"
UNRESOLVED = "UNRESOLVED"
def __init__(self):
"""Initialize"""
pass
def run(self, inp):
"""Run the runner with the given input"""
return (inp, Runner.UNRESOLVED)
As a base class, Runner merely provides an interface for more complex runners that build on it. More specifically, we introduce subclasses that inherit the methods from their superclass in order to add additional methods or to override inherited methods.
Here is one example of such a subclass: PrintRunner simply prints out everything that is given to it, overriding the inherited run() method. This is the default runner in many situations.
In [63]:
class PrintRunner(Runner):
def run(self, inp):
"""Print the given input"""
print(inp)
return (inp, Runner.UNRESOLVED)
In [64]:
p = PrintRunner()
(result, outcome) = p.run("Some input")
Some input
The result is just the string we passed as input:
In [65]:
result
Out[65]:
'Some input'
Still, at this point, we have no way to classify program behavior:
In [66]:
outcome
Out[66]:
'UNRESOLVED'
The ProgramRunner class sends the input to the standard input of a program instead. The program is specified when creating a ProgramRunner object.
In [67]:
class ProgramRunner(Runner):
def __init__(self, program):
"""Initialize. program is a program spec as passed to subprocess.run()"""
self.program = program
def run_process(self, inp=""):
"""Run the program with inp as input. Return result of subprocess.run()."""
return subprocess.run(self.program,
input=inp,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
universal_newlines=True)
def run(self, inp=""):
"""Run the program with inp as input. Return test outcome based on result of subprocess.run()."""
result = self.run_process(inp)
if result.returncode == 0:
outcome = self.PASS
elif result.returncode < 0:
outcome = self.FAIL
else:
outcome = self.UNRESOLVED
return (result, outcome)
Here's a variant for binary (i.e., non-textual) input and output.
In [68]:
class BinaryProgramRunner(ProgramRunner):
def run_process(self, inp=""):
"""Run the program with inp as input. Return result of subprocess.run()."""
return subprocess.run(self.program,
input=inp.encode(),
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
Let us demonstrate a ProgramRunner using the cat program – a program that copies its input to its output. We see that a standard invocation of cat simply does the job, with the output of cat being the same as its input:
In [69]:
cat = ProgramRunner(program="cat")
cat.run("hello")
Out[69]:
(CompletedProcess(args='cat', returncode=0, stdout='hello', stderr=''), 'PASS')
### Fuzzer Classes¶
Let us now define a fuzzer that actually feed data into a consumer. The base class for fuzzers provides one central method fuzz() that creates some input. The run() function then sends the fuzz() input to a runner, returning the outcome; runs() does this for a given number (trials) of times.
In [70]:
class Fuzzer(object):
def __init__(self):
pass
def fuzz(self):
"""Return fuzz input"""
return ""
def run(self, runner=Runner()):
"""Run runner with fuzz input"""
return runner.run(self.fuzz())
def runs(self, runner=PrintRunner(), trials=10):
"""Run runner with fuzz input, trials times"""
# Note: the list comprehension below does not invoke self.run() for subclasses
# return [self.run(runner) for i in range(trials)]
outcomes = []
for i in range(trials):
outcomes.append(self.run(runner))
return outcomes
By default, Fuzzer objects do not do much, as their fuzz() function is merely an abstract placeholder. The subclass RandomFuzzer, however, implements the functionality of the fuzzer() function, above, adding an additional parameter min_length to specify a minimum length.
In [71]:
class RandomFuzzer(Fuzzer):
def __init__(self, min_length=10, max_length=100,
char_start=32, char_range=32):
self.min_length = min_length
self.max_length = max_length
self.char_start = char_start
self.char_range = char_range
def fuzz(self):
"""A string of min_length to max_length characters
in the range [char_start, char_start + char_range]"""
string_length = random.randrange(self.min_length, self.max_length + 1)
out = ""
for i in range(0, string_length):
out += chr(random.randrange(self.char_start,
self.char_start + self.char_range))
return out
With RandomFuzzer, we can now create a fuzzer whose configuration needs to be specified only once when creating the fuzzer.
In [72]:
random_fuzzer = RandomFuzzer(min_length=20, max_length=20)
for i in range(10):
print(random_fuzzer.fuzz())
99:+=0,'(; )85 !.4&0
2/*4-(/807%37?35>;/:
&60:9'>9:;-'3/*&/>'>
)6/0030:*966322#<!#2
,$/7#1507+5##*?*+5-8 !$.)--=>0<91-;08-9,5
:62&(/1'(208&/'.""/=
&)+',:4;;,21#9=6-7?"
*6'>&7 13<&")(%&4/)3
#*1:49!*/3"7$2,9+'*8 We can now send such generated inputs to our previously defined cat runner, verifying that cat actually does copy its (fuzzed) input to its output. In [73]: for i in range(10): inp = random_fuzzer.fuzz() result, outcome = cat.run(inp) assert result.stdout == inp assert outcome == Runner.PASS Combining a Fuzzer with a Runner, however, is so common that we can use the run() method supplied by the Fuzzer class for this purpose: In [74]: random_fuzzer.run(cat) Out[74]: (CompletedProcess(args='cat', returncode=0, stdout="'((;&!*:>1!;*?<70=&<", stderr=''), 'PASS') With runs(), we can repeat a fuzzing run a number of times, obtaining a list of results. In [75]: random_fuzzer.runs(cat, 10) Out[75]: [(CompletedProcess(args='cat', returncode=0, stdout='&1-(-?,(9&=*5-#/<>9&', stderr=''), 'PASS'), (CompletedProcess(args='cat', returncode=0, stdout="3. :9>,/'!!19.0&%?4+", stderr=''), 'PASS'), (CompletedProcess(args='cat', returncode=0, stdout='+\'(,*2$&80#?9%.8"\'+>', stderr=''),
'PASS'),
(CompletedProcess(args='cat', returncode=0, stdout='<,.6:!9*&0#?>.-2=+-;', stderr=''),
'PASS'),
(CompletedProcess(args='cat', returncode=0, stdout='&)=/,/1\'9#,/);45"< 7', stderr=''),
'PASS'),
(CompletedProcess(args='cat', returncode=0, stdout='0675"$/- %?*28? ?\'?;', stderr=''), 'PASS'), (CompletedProcess(args='cat', returncode=0, stdout='0#9;;+/&$ ;>*?,6!#:9', stderr=''),
'PASS'),
(CompletedProcess(args='cat', returncode=0, stdout='!+7;!::0)*6!-4*>:,#5', stderr=''),
'PASS'),
(CompletedProcess(args='cat', returncode=0, stdout='0<67*\')4;./33%91;<"=', stderr=''),
'PASS'),
(CompletedProcess(args='cat', returncode=0, stdout=",0#40'.!;,&-7>&%12<(", stderr=''),
'PASS')]
With this, we have all in place to create fuzzers – starting with the simple random fuzzers introduced in this chapter, but even far more advanced ones. Stay tuned!
## Lessons Learned¶
• Randomly generating inputs ("fuzzing") is a simple, cost-effective way to quickly test arbitrary programs for their robustness.
• Bugs fuzzers find are mainly due to errors and deficiencies in input processing.
• To catch errors, have as many consistency checkers as possible.
## Background¶
Books on generating software tests in general are scarce (which is why we wrote this book). There are a few notable books on fuzzing, though, also based on the basic fuzzing techniques introduced in this chapter:
• The book "Fuzzing – Brute Force Vulnerability Discovery" covers a wide range of fuzzing domains, including files, Web pages, environment variables, and network protocols. The authors bring in lots of experience from fuzzing at Microsoft, and include a number of ready-made tools for Windows and UNIX programs. The tools have aged somewhat, but the principles remain.
• The book "Fuzzing for Software Security Testing and Quality Assurance" \cite{Takanen2008}, now in its second edition 2018, covers a wide range of fuzzing tools and detection techniques; its authors bring in plenty of experience from security testing and vulnerability discovery. This is arguably one of the most comprehensive and up-to-date books on the field.
Specifically for this chapter, the seminal work on fuzzing, introducing both the term and the approach, is "An Empirical Study of the Reliability of UNIX Utilities" \cite{Miller1990}. As the foundation for the field, this is a must-read for anyone interested in fuzzing and robustness testing, with observations as valid today as they were 30 years ago.
## Exercises¶
One of the errors found by Miller et al. \cite{Miller1990} involves the troff typesetting system. Troff takes as input a text consisting of lines; a line beginning with a dot (.) includes typesetting commands, as in
.NH
.LP
Some paragraph
which would produce (using nroff -ms) the text
1. Some Heading
Some paragraph
At the time of Miller et al., troff would fail if its input included
1. The input sequence \D (backslash + D) followed by a non-printable character
2. A character in the ASCII range 128–255 (i.e., the 8th bit is set) followed by a newline character
3. A single dot (.) followed by a newline character.
### Exercise 1: Simulate Troff¶
For each of the above, write a Python function f(s) that fails if s fulfills the failure criterion.
### Exercise 2: Run Simulated Troff¶
Create a class TroffRunner as subclass of Runner that checks for the above predicates. Run it with Fuzzer. Be sure to have the Fuzzer object produce the entire range of characters. Count how frequently the individual predicates fail.
### Exercise 3: Run Real Troff¶
Using BinaryProgramRunner, apply the fuzzer you configured on the real troff program. Check if you can produce any run whose output code is non-zero, indicating a failure or a crash.
|
# DoE completes final draft on forming panel
• Nation
• Monday, 01 Apr 2019
PASIR GUDANG: The Department of Environment (DoE) has completed its final draft for the forming of the Toxic Waste Management and Scheduled Waste National Committee following the chemical spill at Sungai Kim Kim.
Its director-general Datuk Dr Ahmad Kamarulnajuib Che Ibrahim said the draft would be sent to the Energy, Science, Technology, Environment and Climate Change Ministry for approval.
“We have completed the draft. We will present it to the ministry as soon as possible for them to make the final decision.
“The committee will be responsible for any future toxic waste management,” he said during a visit to SMK Taman Pasir Putih here yesterday.
Ahmad Kamarulnajuib said the committee would be the highest platform that could make decisions on how to better manage toxic waste so that the Sungai Kim Kim case would not happen again.
He also stressed that the air quality in Pasir Gudang was back back to normal, but the DoE would continue to monitor the condition of Sungai Kim Kim.
State DOE director Datuk Dr Mohammad Ezanni Mat Salleh said DoE was currently searching for factories responsible for
dumping toxic waste into Sungai Selangkah here.
These factories, he said, had taken advantage of a high tide by releasing their waste into the river during the rainy season.
“We have identified 113 factories along Sungai Selangkah within a radius of 10km.
“We have identified 20 to 30 factories which are potential suspects,” Mohammad Ezanni said, adding that DoE had yet to establish if the toxic waste that polluted Sungai Selangkah was the same type dumped into Sungai Kim Kim.
Related stories:
Many people still wearing face masks
Article type: metered
User Type: anonymous web
User Status:
Campaign ID: 7
Cxense type: free
User access status: 3
|
# 1. NDK integration is deprecated in the current plugin
FAILURE: Build failed with an exception.
* What went wrong:
> Error: NDK integration is deprecated in the current plugin. Consider trying the new experimental plugin. For details, see http://tools.android.com/tech-docs/new-build-system/gradle-experimental. Set "\$USE_DEPRECATED_NDK=true" in gradle.properties to continue using the current NDK integration.
# 2. Native C/C++ source code is found, but it seems that NDK option is not configured
Warning: Native C/C++ source code is found, but it seems that NDK option is not configured. Note that if you have an Android.mk, it is not used for compilation. The recommended workaround is to remove the default jni source code directory by adding:
android {
sourceSets {
main {
jni.srcDirs = []
}
}
}
to build.gradle, manually compile the code with ndk-build, and then place the resulting shared object in src/main/jniLibs.
## 解决
sourceSets {
main {
jni.srcDirs = []
}
}
BUILD SUCCESSFUL
|
# Divergence Theorem checks
1. Apr 21, 2012
### bugatti79
1. The problem statement, all variables and given/known data
Folks, have I set these up correctly? THanks
Use divergence theorem to calculate the surface integral \int \int F.dS for each of the following
2. Relevant equations
$$\int \int F.dS=\int \int \int div(F)dV$$
3. The attempt at a solution
a) $$F(x,y,z)=xye^z i +xy^2z^3 j- ye^z k$$ and sigma is the surface of the box that is bounded by the coordinate planes and planes x=3, y=2 and z=1
Attempt
$$\int_0^3 \int_0^2 \int_0^1 2xyz^3 dzdydx$$ where $$div (F)=ye^z+2xyz^3-ye^z$$
b) $$F(x,y,z)=3xy^2 i+xe^zj+z^3k$$ and sigma is surface bounded by cylinder y^2+z^2=1 and x=-1 and x=2
Attempt
$$\int_0^{2\pi} \int_0^{1} \int_{-1}^{2} (3r^2) r dxdrd\theta$$ where $$div(F)=3y^2+3z^2$$
c)$$F(x,y,z)=(x^3+y^3)i+(y^3+z^3)j+(x^3+z^3)k$$ and sigma is sphere of r=2 and centre 0,0
Attempt
$$\int_0^{2\pi} \int_0^{\pi} \int_0^{2} 3p^4 sin(\phi) dp d\phi d\theta$$ where $$div(F)=3(x^2+y^2+z^2)$$...?
Thanks
2. Apr 21, 2012
### tiny-tim
hi bugatti79!
yes, they all look fine
(was anything worrying you about that? )
3. Apr 22, 2012
### bugatti79
Thanks. I just wanted to make sure before I proceeded. Here are 3 more trickier ones.
d) $F(x,y,z)=x^2 sin(y) i+x cos (y) j-xz sin(y) k$ and sigma is the surface x^8+y^8+z^8=8
Dont know how to tackle sigma. I thought I could manipulate it using the equation of a sphere.
e) $F(x,y,z)=x^4 i+x^3z^2 j +4y^2z k$ and sigma is the surface of the solid that is bounded by the cylinder x^2+y^2=1 and the planes z=x+2 and z=0
$\displaystyle \int_0^{2\pi} \int_0^1 \int_0^{rcos(\theta)+2} (4x^3+4y^3)r dx dr d\theta=$
$\displaystyle\int_0^{2\pi} \int_0^1 \int_0^{rcos(\theta)+2} (4r^3cos^3(\theta)+4r^2sin^2(\theta))r dx dr d\theta$
where $x=rcos(\theta)$, $y=rsin(\theta)$ and $div(F)=4x^3+4y^2$
f)$F(x,y,z)=\frac{r}{||r||}$ where $r=x i+yj+zk$ and sigma consists of the hemisphere $z=\sqrt{1-x^2-y^2}$ and the disc and $x^2+y^2\le1$ in the xy plane
This looks like its going to be tedious...? $\displaystyle div(F)=\frac{\partial}{\partial x}\frac{x}{(x^2+y^2+z^2)^{1/2}}+\frac{\partial}{\partial y}\frac{y}{(x^2+y^2+z^2)^{1/2}}+\frac{\partial}{\partial z}\frac{z}{(x^2+y^2+z^2)^{1/2}}$...........?
4. Apr 22, 2012
### tiny-tim
hi bugatti79!
erm
first, what's divF ?
(i assume you meant 4x3 + 4y2zk and dz ?)
yes, that looks ok
just keep going, it's quite easy and it'll simplify out in the end
5. May 11, 2012
### bugatti79
$div(F)=0$!! What does that mean physically and mathematically?
Not sure I follow..but should it be
$\int_0^{2\pi} \int_0^{1} \int_0^{r \cos \theta +2} (4x^3+4y^3)dzdA$ where $da=r dr d\theta$..?
Thanks
6. May 11, 2012
### tiny-tim
mathematically, it means the integral will be 0
physically, it means F is a conserved flow
my "zk" was a copy-and-paste error, it should have stopped at 4x3 + 4y2
and yes the dx (in dA) should have been dz
7. May 12, 2012
### bugatti79
Thank you sir :-)
8. May 12, 2012
### HallsofIvy
Staff Emeritus
You are aware that this is just $\nabla F= 2xyz^3$ aren't you?
$$2\left(\int_0^3 x dx\right)\left(\int_0^2 y dy\right)\left(\int_0^1 z^3 dz\right)$$
|
## learn demand and supply
Knitting Patterns For Cake Yarn, Fertilising Mango Trees In Perth, Black Pedestal Fan, Gold Exchange Standard, Thermoset Vs Thermoplastic, Peterson Field Guide App, Popeyes Yearly Profit, Endless Summer Tabletop Fire Pit, Quotes About Obeying The Law, Scale Length Guitar, Azure Data Architect Interview Questions,
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# Rendering only a part of text FTGL, OpenGL
I'm using FTGL library to render text in my C++ project.
I can easily render text by using:
CFontManager::Instance().renderWrappedText(font, lineLength, position, text);
Unfortunately there is a situation in which this Button which displays text, is partly hidden because of resizing container in which it is situated. I'm able without any problem to draw Button's background to fit the container, but I've got a problem with doing the same with a text. Is it possible to somehow draw only text for given width and the rest just ignore?
This is a screen which presents my problem:
• I think you'd have to figure out the width of your text string based on font size beforehand somehow, and then only print what would fit based on that. I don't know if FTGL has a way to do that or not. – Eric B Nov 26 '12 at 12:55
• @EricB That's what I was afraid of... I think FTGL doesn't have such possibility. But even though if I achieve this, I would be able only to cut off specific number of letters. What if I'd like to cut one letter (for example 'k' on sample screenshot I gave) in a half? Is it impossible? – Piotr Chojnacki Nov 26 '12 at 13:03
• nothing's impossible, but to do that you would certainly have to use standard freetype and then manipulate the bitmaps it gives you yourself, messing with the texture coordinates and so on. So... what you're looking for CAN be done, but not quickly or easily. – Eric B Nov 26 '12 at 13:15
• @Mosquito: Please stop cross-posting questions. – Nicol Bolas Nov 26 '12 at 23:09
glEnable(GL_SCISSOR_TEST);
|
## Physics: Principles with Applications (7th Edition)
Published by Pearson
# Chapter 27 - Early Quantum Theory and Models of the Atom - Questions: 16
#### Answer
-Both have wave and particle properties -Photons are not charged while electrons have a negative charge -Photons have no mass while electrons have mass -Electrons must obey the Pauli exclusion principle while Photons do not -Photons travel at the speed of light while electrons must always travel under this speed
#### Work Step by Step
The characteristics of each are listed below. Photon: It has both wave properties, and particle properties. It has a wavelength and can be scattered. It is not charged. It has no mass. It does not obey the Pauli exclusion principle. Always travels at the speed of light. Electron: It has both wave properties, and particle properties. It has a wavelength and can be scattered. It has a charge of $-1.602 \times 10^{-19} C$. It has a mass of $9.11 \times 10^{-31} kg$. It obeys the Pauli exclusion principle. It travels at speeds strictly less than the speed of light.
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.
|
### Locally Decodable Quantum Codes
Jop Briet & Ronald De Wolf
We study a quantum analogue of locally decodable error-correcting codes. A $q$-query \emph{locally decodable quantum code} encodes $n$ classical bits in an $m$-qubit state, in such a way that each of the encoded bits can be recovered with high probability by a measurement on at most $q$ qubits of the quantum code, even if a constant fraction of its qubits have been corrupted adversarially. We show that such a quantum code can be transformed into...
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# Using continuity correction for normal approximation or not?
Below is a question on a recent actuarial exam, Exam 3L of the CAS. I didn't know whether or not to use the continuity correction when using the normal approximation to do hypothesis testing involving a bernoulli trial. The answer is vastly different (based on the answer choices given in the exam) depending on whether or not you use it. The problem does not specify to use it or to not use it, though some previous problems have specified one or the other, whereas others have not specified either.
You are given the following:
• Accidents happen during a work day at a probability of p when a machine is operated.
• The null hypothesis $H_0$ is that the probability of an accident is 0.05; the alternative hypothesis $H_1$ is that the probability is less than 0.05.
• If less than 20 accidents are observed in 365 work days, then reject the null hypothesis.
Using the normal approximation, calculate the probability of Type II error using the value 0.03 as the true probability of an accident occurring.
Any help would be greatly appreciated. Just to be clear, I am hoping to better understand when it should be used and when it should not be used, in general, in addition to learning the best way to do this problem.
• please add the self-study tag May 6, 2013 at 0:16
• @Glen_b Well, "Preliminary answers" have the non-continuity correction version as the answer but we have a few days to email them and tell them why they should accept others. The exam has several mistakes in it, which is frustrating. May 10, 2013 at 21:17
• Well, if you want to, you can easily argue for the correction in this case, since it's often used and in this case gives a better approximation to the exact binomial probability. It would be hard to argue against it! If I was marking it, I'd accept either... and then if I wrote it, I'd have to smack myself for asking a question where it made enough difference to worry about. May 11, 2013 at 2:44
I can't speak to what the people setting the exam might do; sometimes the actuarial choices on statistical matters baffle me.
I can only speak to what I see as the statistics issues.
Given 20 is pretty much near the middle of the null distribution, which itself is reasonably well approximated by a normal, the continuity correction will greatly improve the accuracy of probability calculations there. So if you were trying to compute the type I error rate, it's quite useful.
(These are ridiculous type I error rates, by the way; the mean, median and mode of the null are included in the rejection region! A more sensible critical value would be somewhere around 13 or likely even less; best places to put the critical value depends on the relative cost of the two types of error)
However, while the continuity correction works well for calculating the Type I error rate, for the considered alternative (p = 0.03), the critical value is way in the tail and then the continuity correction often unhelpful; I'd have leaned toward avoiding it. (And since the alternative is what the question is about... that's where it matters)
But I'd be unsurprised if the actuaries have not covered such details in the course - that the continuity correction works very well when you have exact symmetry and more generally works well when you're toward the mean of the binomial, and often does badly when you are in the far tail of asymmetric distributions (p far from 0.5), though it depends on which direction you're looking. I don't know if you're supposed to consider this issue in this way.
It turns out that the results in this case are:
The exact Type II error rate is 0.0079, with continuity correction it's 0.0044, and without it's 0.0027 (assuming I got it right the second time around).
It looks like my inclination to avoid it in this case was of no benefit, though neither approximation is very good.
• Are you sure about the 0.0017. I got something like 0.0044 with the continuity correction. If I reject by getting 19 or less than, then I'm talking about the probability of 20 or more to not reject which would be 19.5 or more using the continuity correction, right? Also, yes, I noticed while taking the test that the mean is inside the rejection region. Thanks for this detailed response. This is the sort of thing that is going to help me understand things better. May 6, 2013 at 1:09
• My mistake; I misread the rejection rule as 20 or less when it's 'less than 20'. Two of those figures change (now fixed). The rejection region includes its boundary so it's kind of weird to state it in terms of an open interval (less than 20) instead of a closed one (19 or less). May 6, 2013 at 2:01
• The CAS is going to put out the answers tomorrow, or so I have heard. So, I can see if they agree with my using the continuity correction. If not, I can easily argue that it's a much better approximation (though still poor as you said), so I can try to get them to accept my answer :) May 6, 2013 at 2:47
This is a "find the mistakes" question.
When you see "accident", think Poisson, not Bernoulli, process.
The process average "p" needs a rate of occurrence: .05/workday. It is not a "Probability".
The H0 and H1 as stated, call for a Type1 Risk. Let's make it 5%.
And the question becomes: What is the largest number of accidents in the past workyear that would have you reject H0?
Using the Normal Approximation, the answer: 10
There follows •If less than 20 accidents are observed in 365 work days, then reject the null hypothesis. "20" is a mistake; it should be "11"; but, in any case, less than "18".
The test question is then modified.
|
## The Annals of Probability
### A New Formula for $P(R_i \leqq b_i, 1 \leqq i \leqq m \mid m, n, F = G^k)$
G. P. Steck
#### Abstract
Let $X_1 \leqq X_2 \leqq\cdots \leqq X_m$ and $Y_1 \leqq Y_2 \leqq \cdots \leqq Y_n$ be independent samples of i.i.d. random variables from continuous distributions $F$ and $G$, respectively, and suppose $F(x) = \lbrack G(x)\rbrack^k$ or $F(x) = 1 - \lbrack 1 - G(x)\rbrack^k, k > 0.$ Let $R_i$ and $S_j$ denote the ranks of $X_i$ and $Y_j$, respectively, in the ordered combined sample. We express $P(R_i \leqq b_i$, all $i$) as the determinant of a simple $m \times m$ matrix. We also show that for increasing sequences $\{a_i\}$ and $\{b_i\}, P(a_i \leqq R_i \leqq b_i$, all $i\mid F, G) = P(\alpha_j \leqq S_j \leqq \beta_j$, all $j\mid F, G)$, where $\{\alpha_j\} = \{b_i\}^c$ and $\{\beta_j\} = \{a_i\}^c$ and complementation is with respect to the set $\{i\mid 1 \leqq i \leqq m + n\}$, for any pair of continuous distributions $F$ and $G$.
#### Article information
Source
Ann. Probab., Volume 2, Number 1 (1974), 155-160.
Dates
First available in Project Euclid: 19 April 2007
https://projecteuclid.org/euclid.aop/1176996761
Digital Object Identifier
doi:10.1214/aop/1176996761
Mathematical Reviews number (MathSciNet)
MR359127
Zentralblatt MATH identifier
0277.62013
JSTOR
Steck, G. P. A New Formula for $P(R_i \leqq b_i, 1 \leqq i \leqq m \mid m, n, F = G^k)$. Ann. Probab. 2 (1974), no. 1, 155--160. doi:10.1214/aop/1176996761. https://projecteuclid.org/euclid.aop/1176996761
• Acknowledgment of Prior Result: G. P. Steck. Note: Acknowledgment of Priority to "A New Formula for $P(R_i \leqq b_i, 1 \leqq i \leqq m \mid m, n, F = G^k)$". Ann. Probab., Vol. 3, Iss. 4 (1975), 739.
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723 articles – 3326 Notices [english version]
HAL : in2p3-00704527, version 1
XX International Workshop on Deep-Inelastic Scattering and Related Subjects, DIS 2012, Bonn : Allemagne (2012)
Measurements with ATLAS detector of jets containing charm and bottom quarks
ATLAS Collaboration(s)
(2012)
The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass, the azimuthal angle difference between the two jets, and the angular variable chi in two dijet mass regions. The results are compared to next-to-leading-order QCD predictions. D*+/- meson production in jets is also measured. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate.
Thème(s) : Physique/Physique des Hautes Energies - Expérience
Mot(s)-clé(s) : QCD
in2p3-00704527, version 1 http://hal.in2p3.fr/in2p3-00704527 oai:hal.in2p3.fr:in2p3-00704527 Contributeur : Jeanine Pellet <> Soumis le : Mardi 5 Juin 2012, 16:08:56 Dernière modification le : Mercredi 6 Juin 2012, 07:33:00
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# Would like to know how to create a SuperMario Galaxy type movement
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Hello, i would like to know how to create relative movement on a 3d sphere. ie. i have got the earth(is really round in 3d), now i would like to know how to move on it.(Eg. is Super Mario Galaxy for the wii) one thing that i know : person.translate(0, radius, 0) person.rotateX(x) person.rotateZ(y) where x += speed * cos(direction) , y += speed * sin(direction) and direction is the angle the person is facing.
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Quote:
Original post by adityav89Hello, i would like to know how to create relative movement on a 3d sphere.ie. i have got the earth(is really round in 3d),now i would like to know how to move on it.(Eg. is Super Mario Galaxy for the wii)one thing that i know :person.translate(0, radius, 0)person.rotateX(x)person.rotateZ(y)where x += speed * cos(direction), y += speed * sin(direction)and direction is the angle the person is facing.
I didn't follow the method described in your post completely (partly because I don't know what the 'translate', 'rotateX', and 'rotateZ' functions do), but I'm not sure if it'll work the way you're expecting. (Have you tried it yet? If so, what were the results?)
In any case, here's how I'd do it. Instead of trying to create the player transform from scratch each frame, store it from frame to frame and update it incrementally.
First, choose an initial transform for the player (e.g. standing at one of the 'poles' of the sphere). Then, for each update:
// Update yaw (note that this is done using a rotation about the local up axis):person.rotate_about_local_up(yaw_delta);// Update the position. This will move the player tangent to the sphere, so after this step// the player will be 'floating' above the sphere a bit.person.position += person.forward * speed * time_step;// Get the sphere normal corresponding to the point directly under the player:vector normal = normalize(person.position);// Drop the player back down to the surface:person.position = normal * sphere.radius;// Now the person is on the surface, but probably isn't perfectly 'upright' with respect// to it, so we apply a normalizing relative rotation to correct this:matrix rotation = matrix_rotate_vec_to_vec(person.up, normal);person.apply_rotation(rotation);
Obviously this skips over quite a few details, but ultimately it breaks down to just a few math functions that should be provided by any good math library. If you need help with the details though, feel free to ask.
(Note that the way in which forward motion is applied above is somewhat approximate with respect to the speed of the player. I used this method because it's simple and straightforward, but a more accurate method would be to move the player along the 'great circle' that lies in the same plane as the player's forward vector. Depending on how this movement is applied, you might still want to 'renormalize' the player position afterwards. The step where you realign the player to the sphere surface would remain the same.)
[Edit: Fixed typo.]
[Edited by - jyk on February 20, 2010 9:26:50 PM]
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No, i know about pitch, yaw and roll they're same as rotatingXYZ but would like to know a mathematical sequence to multiply the matrices.
Let assume i got a sphere at point 0,0,0 with radius 10
now i got a man who would like to move above the sphere.
So what do i need to do now?
What i did was
translate the man to (0, 10, 0)
then i need to rotate him along some axis that i just cant get right.
THIS IS MY XNA Code :
----------------------
public void PartOfPlanet(Planet planet)
{
world = Matrix.CreateRotationY(MathHelper.ToRadians(Direction)) * Matrix.CreateTranslation(0, planet.Size + 0.25f, 0) *
Matrix.CreateRotationX(pos.X) * Matrix.CreateRotationZ(pos.Y) * planet.AxisAndAlign;
cam_lookat = world.Translation;
Matrix tmp = Matrix.CreateTranslation(0, 10, 10) * world;
cam_pos = tmp.Translation;
XBase.UpdateCamera(cam_pos, cam_lookat);
}
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Quote:
Original post by adityav89No, i know about pitch, yaw and roll they're same as rotatingXYZ but would like to know a mathematical sequence to multiply the matrices.Let assume i got a sphere at point 0,0,0 with radius 10now i got a man who would like to move above the sphere.So what do i need to do now?What i did was translate the man to (0, 10, 0)then i need to rotate him along some axis that i just cant get right.THIS IS MY XNA Code :----------------------public void PartOfPlanet(Planet planet) { world = Matrix.CreateRotationY(MathHelper.ToRadians(Direction)) * Matrix.CreateTranslation(0, planet.Size + 0.25f, 0) * Matrix.CreateRotationX(pos.X) * Matrix.CreateRotationZ(pos.Y) * planet.AxisAndAlign; cam_lookat = world.Translation; Matrix tmp = Matrix.CreateTranslation(0, 10, 10) * world; cam_pos = tmp.Translation; XBase.UpdateCamera(cam_pos, cam_lookat); }
If you re-read my post and the article that raigan linked to, you should see that the method(s) being described don't involve building a transform for the player 'from scratch' each update. Rather, the player transform is adjusted incrementally each update, with the goal of keeping the player 'on' the surface beneath them (more or less) and aligned with the surface normal. This is the approach I'd recommend.
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I did see the article but however for my really simple game i just created a simple sphere without normals, i also saw how the spherical co-ordinate system works but i didnt get the exact type of movement i needed.
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After some googling for math, i finally know what i need , its how to :
convert 2d Cartesian coords to a point on the sphere OR Spherical coord.
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Quote:
I did see the article but however for my really simple game i just created a simple sphere without normals, i also saw how the spherical co-ordinate system works but i didnt get the exact type of movement i needed.
Normals shouldn't be a problem. The unit-length normal at any point p on the surface of a sphere can be computed trivially as normalize(p - sphere.center). If the sphere is centered at the origin, that just becomes normalize(p).
Quote:
After some googling for math, i finally know what i need , its how to :convert 2d Cartesian coords to a point on the sphere OR Spherical coord.
I'm not sure how you would map strictly 2-d motion to a sphere in the way you describe and still get good results, but maybe someone else will be able to offer some advice in that area.
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I think im gonna go with the normals method, but i couldnt understand the BasicBlitz code that was written and how its mapped to the input.
it says that u should get the normal vector from the player's pos - center but how to represent the players pos.?
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Quote:
it says that u should get the normal vector from the player's pos - center but how to represent the players pos.?
Typically you would represent the player's position using a 3-d vector (more specifically, a point [x, y, z] defined relative to the 3-d Cartesian coordinate system).
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The momentum (in kg-m/s) of photon having 6 MeV energy is x×10-21;what is x
# The momentum (in kg-m/s) of photon having 6 MeV energy is $\mathrm{x}×{10}^{-21}$;what is x
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Teigen Jan Gunnar jan.teigen at vegvesen.no
Sat Nov 12 17:43:09 CET 2005
Hey
I am writing on a document for some 'rules and regulations' in pdfTex
where I use the paragraph sectioning command a lot. It is not practical
to include these paragraphs in the Table of Content since they are
numerous and without heading (but I include them as bookmarks). However,
it is 'a must' to be able cross-referencing the individual paragraphs.
So far, I have used a LaTex-structure like this for each paragraph:
%**************************************************
\paragraph*{\theparagraph\hspace{-1em}}
\pdfbookmark[4]{\theparagraph}{\theparagraph}
\label{key}
%**************************************************
Text of the paragraph ..........
This works fine for the bookmark, and also for the hyperlink when I
However, the problem is that '\ref{key}' yields the overlaying
subsection-number (which is in ToC), instead of the actual
paragraph-number.
I understand that this is not a bug in LaTex, just the way it is meant
to work. However, what I miss here is the following extention of the
ref-command: \ref[counter]{key}, with a counter optional (in my case
paragraph). Maybe this can be enabled using the \renewcommand, but I
don't have the skills.
COan you help me finding a way around this problem?
Kind regards
Jan Teigen
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# Is the Noether charge always a Hermitian operator?
Noether's theorem tells us that to every continuous symmetry of the Lagrangian there corresponds a conserved current $j^\mu$. From the time component of this current, we can then define the Noetherian charge $$Q = \int d^3\mathbf{x}\ j^0(\mathbf{x}),$$ which is a time independent operator. In all examples I've seen, the Noether charge $Q$ is always a Hermitian operator (up to a trivial rescaling by $i$). But no one ever seems to explicitly mention this fact in full generality.
Can we prove that Noether's theorem will always give us a Hermitian charge operator? If not, are there counter-examples?
The Noether charge is the generator of the symmetry it belongs to, see e.g. this answer by Qmechanic. This relationship is also preserved in the quantum theory, see this question, in the sense that the quantum Noether charge $Q$ must commute with the Hamiltonian $H$, at least in the absence of anomalies and if we do not run into "quantization issues" when using canonical quantization.
Now, if we assume that the classical symmetry transformation must be represented by a unitary transformation upon the Hilbert space (note: I'm not assuming it is a quantum symmetry transformation), then we can directly conclude by Stone's theorem that $Q$ is Hermitian and that the transformation associated to the classical symmetry is indeed a symmetry.
We might ask whether one can drop this assumption, I think one cannot. Dropping the requirement that transformations are represented by unitary operators leads to the normalization of states not being preserved, in particular, it means that the probabilities after the transformation to find one state in other states that form a basis do not sum to 1. This wrecks havoc with the entire structure of the quantum theory; it is a reasonable physical assumption that all physical transformations be represented unitarily upon the Hilbert space of states.
• @AccidentalFourierTransform Finite-dimensional representations are not the representations on the Hilbert space of the theory (precisely because they are not unitary), they just live on the target space of the fields, hence Wigner's theorem doesn't hold. When we speak of "generators" or "Noether charge" in quantum mechanics, we generally mean an operator on the space of states, not on the target space of fields. – ACuriousMind Apr 8 '16 at 17:09
• Wigner's theorem is a statement about symmetries acting on the underlying Hilbert space. Noether's theorem concerns symmetries internal to the Lagrangian. I'm not too sure how the two are related. In particular, I'm not entirely convinced that every symmetry for the Lagrangian needs to be unitary. – EuYu Apr 8 '16 at 17:27
• @EuYu: That's why I linked what I linked. In the Hamiltonian framework, the Noether charge generates the symmetry. After (canonical) quantization, the Hamiltonian symmetries and generators correspond to operators on the Hilbert space, and then Wigner's theorem hits and tells us the symmetry operator must be unitary. I don't see where you see a gap in this argument. – ACuriousMind Apr 8 '16 at 17:33
• Oh, yes, that is correct. See also this post, you're looking at the "wrong thing" to decide hermiticity. We would have to take the adjoint of the $\sigma$ in their representation on the Hilbert space, not on the non-unitary finite-dim rep to conclude whether or not $J$ is Hermitian. Whether or not it is Hermitian in the representation on the target space of the fields is a physically irrelevant information, at least it has no meaning I could see. – ACuriousMind Apr 8 '16 at 17:37
• Thanks for the updated answer. I agree for the most part, but it still doesn't seem satisfying. If we have a symmetry of the Lagrangian, we don't get to pick the charge that comes out. The associated symmetry $V(\theta)=e^{i\theta Q}$ will either be unitary or not, and this is not a condition we can set. Of course, we can reject any symmetries of the Lagrangian which generates such a non-unitary $V$ as non-physical, which is what I think you're suggesting. But the underlying mathematical problem is whether such non-physical symmetries exist in the first place, and that hasn't been resolved. – EuYu Apr 8 '16 at 19:39
Supersymmetry generators are not always Hermitian. If you impose SUSY, and then compute de corresponding Noether's currents, and then you calculate the conserved charge, i.e., the fermionic Lorentz generators, you will get two non-Hermitian conserved currents.
(By the way, the relation $Q^\dagger=\bar Q$ is only valid in Lorentzian signature, in Euclidean signature, this relation is not true.)
Actually, a nice computation of this was made by Olive and Witten. They did just what I outlined for $\mathcal N=2$ SYM without matter fields and obtained the central charge of this theory. See section 2.8 of http://arxiv.org/abs/hep-th/9701069 for a detailed computation.
Also, not always you would get a pair $Q$ and $\bar Q$. Just take, for example, $\mathcal N=(n,m)$ 6D theories.
The moral of this story is the following: You will always assume $S=S^\dagger$ (a real action.) If your symmetry generator is also Hermitian, the conserved current, and therefore, the conserved charge, will also be Hermitian. But this might not be the case.
• Might the "fermionic Lorentz generators" be "non-Hermitian" for the same reason the Boosts are not unitary? I.e. are you taking the adjoint as operators on the target space of the field, and not on the Hilbert space of the theory? This is not a true counterexample to generators being unitary, since the relevant notion of "unitary/self-adjoint" is that of operators on the Hilbert space of states, not on the target space of the fields. – ACuriousMind Apr 11 '16 at 16:20
• First of all, the initial question was about Hermitian Noether charges, and nothing about unitarity. I just answered that. Second, the supercharges acting on a state does not change the "unitarity" of the system (I think this answer the first part of your question.) Second, to "create" states in the Hilbert space of the theory (which is the second part of your question) you have to construct, out of the supercharges, the $a$ and $a^\dagger$, which, as in the harmonic oscillator case, are not Hermitians. – CGH Apr 12 '16 at 14:04
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#### Docker container No such file directory found
I am a new learner of Docker. I tried to build an image to run a previously written program package that is designed to run in a Linux environment. The package also uses a makefile and Make command to run.
Below is my Dockerfile
FROM ubuntu:latest
FROM python:latest
WORKDIR /
RUN pip install virtualenv
RUN pip install -r requirements.txt
CMD make all
My idea is to do it as simple as possible. In this case, I want to build a Linux image to let me run the makefile. The above Dockerfile allowed to build an image successfully. But when I run it, I got
FileNotFoundError: [Errno 2] No such file or directory: ‘/TGM-code/data/processed/MICAB/file.tsv
when the container starts to run the python scripts.
I have placed the Dockerfile at the parental directory, and not changed the file directory structure at all. Please help me understand what is my problem.
Source: StackOverflow
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# A Dollar for a Tree or a Tree for a Dollar? The Behavioral Effects of Measurement Basis on Managers’ CSR Investment Decision
A full copy of this paper can be obtained from co-author, Dr. Adam Vitalis at the University of Waterloo, Canada ([email protected])
## Introduction
In recent years, Corporate Social Responsibility (CSR) has taken on more importance and visibility. Boards and CEOs convey their support for CSR by allocating budgets; many give middle managers discretion to spend these monies as they see fit. By decentralizing CSR budgets, firms hope to simplify CSR administration, better motivate managers and their teams, and leverage managers’ knowledge of their communities to make better CSR investment decisions.
Despite leadership’s desire to increase CSR spending, however, some managers do not believe in redirecting profits or shareholder returns to societal causes. Not surprisingly, these CSR non-supportive managers spend significantly less of their budget than those who support CSR. In this study, the researchers sought to understand whether a benign nudge might cause managers to spend more of their CSR allocations.
With undergraduate students and managers as participants, the researchers devised a series of experiments. Subjects were placed in scenarios in which they could spend up to $1,000 to support tree planting, but the more they spent planting trees the lower their personal renumeration for participating. Both pro and anti-CSR managers were asked how many tree plantings they would support at$1 per tree. One group of participants was asked how much money they would allocate to tree planting. Another – the nudge group – was asked how many trees they would plant.
Rationally, managers should not be swayed by either version of the question because each represents exactly the same proposition: 1 per tree planted. Nonetheless, the researchers hypothesized that by simply framing the question differently, the non-economic frame (the nudge) would better align with CSR supportive managers, leading to increased CSR spending. In each experiment, the researchers confirmed their main hypotheses: the nudge caused some managers – those who support CSR - to spend significantly more but had no effect on anti-CSR managers. Where a manager is already pro-CSR, nudging them into a CSR supportive mindset when deciding how much to allocate to tree planting causes them to spend more. ## Assumptions Tested (Hypotheses) In most circumstances, managers will decide how much to allocate to a CSR cause in dollar terms. The researchers believe that this puts them into a traditional financial mindset of costs and benefits. However, when the activity is framed in terms of the number of trees planted, meals distributed, etc., it aligns the giving with personal norms (i.e., increases salience). This triggers the relevant social values of managers who support CSR. In determining how many trees to plant (pay for) they will think less about costs and benefits and more about the good being done by the firm. This will cause them to spend significantly more. Again, prior to the experiments, the researchers reasoned that this effect would apply only to pro-CSR managers because non-CSR supportive managers don’t possess the social values activated by the nudge. ## The Experiments 1. Potential participants were tested two weeks before the experiments to determine their support of CSR. Those who were either clearly pro or anti-CSR were selected. 2. In the main experiment, 34 undergraduate students assumed the role of a corporate manager within a pro-CSR firm who is allocated up to1000 (in experimental “EXP$” dollars) to spend on tree planting. Participants are told that 1% of whatever they spend actually goes to a tree planting organization, and 1% of what they don’t spend goes to them. 3. Participants were randomly selected into two groups. One group decided how much money to spend on planting trees, the other how many trees to plant. Again, both groups knew that each tree cost$1 to plant.
4. In a separate experiment, instead of dollars, 38 different undergraduate participants – all pro-CSR – were given company “credits” in determining how many tree plantings to pay for. One credit equaled one dollar. Participants could spend up to 1,0000 credits.
5. As part of the same experiment, participants were also given a double condition. They were asked to complete either statement: “I want to spend $______ planting ______ trees,” or “I want to plant ______ trees for$______.”
6. Finally, 38 experienced managers were put through the main experiment but asked to imagine a higher budget (between $100,000 to$300,0000 on tree planting).
## Results
• In the main experiments – involving both undergraduates and professional managers – pro-CSR participants spent significantly more when nudged with the non-financial condition. Pro-CSR managers spent more than non-supportive CSR managers, and significantly more when their choices were framed in terms of the number of trees they chose to plant (non-financial) versus the amount of money they decided to spend (financial/economic).
• The researchers predicted that pro-CSR managers would spend more because the non-financial frame triggers their pro-social values. However, an alternative view could be that the difference was due to the financial frame suppressing pro-social inclinations, causing them to spend less. To address this concern, participants in the credit condition – one that neutralizes both financial and non-financial triggers – spent far less than they did in the non-financial condition. This lends strong weight to the researchers’ hypothesis that pro-social triggers are activated when the choice is presented as number of trees versus amount of spend (impact vs. money).
• In work settings, managers would most likely consider both quantity and price. That is, they would think along the lines of how many trees they can get planted at what cost. Remarkably, when pro-CSR participants are asked to make a choice: “I want to plant ______ trees for $______” vs. “I want to spend$______ planting ______ trees,” the difference between the non-financial and financial frames holds. This too lends tremendous support to the researchers’ hypotheses (Figure 1 provides a stark illustration).
Figure 1. Number of trees planted by pro-CSR managers by condition
## Key Takeaways
• Even when spending on CSR reduces their compensation, managers who support CSR spend considerably more on CSR than managers who do not support CSR. More surprisingly, pro-CSR managers can be easily nudged to spend more than they would otherwise simply by framing their choices to emphasize the impact of their contribution vs. the cost.
• Firms that decentralize CSR spending and that aim to increase spending on CSR activities should first hire candidates who believe strongly in CSR and then frame CSR spending choices to emphasize impact.
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# Can we prove that $t$ must be a Mersenne prime?
This question
Equations involving arithmetic functions, totatives and even perfect numbers
can be answered positive if the following can be proven.
Let $t\ge 1$ be an integer and denote $$s:=\sigma\left(\frac{t(t+1)}{2}\right)$$ $$p:=\varphi\left(\frac{t(t+1)}{2}\right)$$
$\sigma(n)$ is the divisor-sum-function and $\varphi(n)$ the totient-function.
Claim :
• If $s=4p+t+1$ holds, then $t$ is a Mersenne-prime.
• If $t^2-1=4p$ holds, then $t$ is a Mersenne-prime.
The claim is true for $t\le 10^6$
• I think I can prove that $t$ is Mersenne prime if both $s=4p+t+1$ and $t^2-1=4p$ hold. Judging by the other question you quoted, there is an "and" in between. Is this what you are after? – rtybase Apr 21 '18 at 11:20
• This is a useful partial result , but I think the formulation clearly indicates that I search a proof of each implication. Perhaps, $t^2-1=4p\implies t$ is Mersenne-prime is easier to show. – Peter Apr 21 '18 at 14:00
• Probably. Technically, propositions 1 to 3 use only $t^2-1=4p$ ... work in progress ... the only scaring factor is Wikipedia mentioning "It is unknown whether there is any odd perfect number ..." – rtybase Apr 21 '18 at 14:53
If both $$t^2-1=4p \tag{1}$$ $$s=4p+t+1 \tag{2}$$
hold. We can deduce:
Proposition 1. $t$-odd.
Easy to see from $(1) \Rightarrow t^2=4p+1$.
Proposition 2. If $t=2k+1$ then $$k(k+1)=\varphi(2k+1)\varphi(k+1)=p$$
Given $\gcd(t,t+1)=1$ and $\varphi(n)$ is multiplicative, which means $$p=\varphi\left(\frac{t(t+1)}{2}\right)=\varphi\left(t\right)\varphi\left(\frac{t+1}{2}\right)$$ then $(1)$ becomes $$t^2=4\varphi\left(t\right)\varphi\left(\frac{t+1}{2}\right)+1 \tag{3}$$ Substituting $$k(k+1)=\varphi(2k+1)\varphi(k+1)$$
Proposition 3. $t$-is square free
If $q$-prime has the property that $q^2 \mid t \Rightarrow q \mid \varphi(t)$. But then, from $(3) \Rightarrow q \mid 1$ - contradiction.
Proposition 4. $\frac{t(t+1)}{2}$ is a perfect number.
I.e. $t+1=s-4p$ and $$(t-1)(t+1)=4p \iff (t-1)(s-4p)=4p \iff t(s-4p)-s+4p=4p \iff \\ t=\frac{s}{s-4p}$$ But $t$-is odd (propositions 1 and 2) $$2k+1=\frac{s}{s-4k(k+1)} \iff 2k=\frac{4k(k+1)}{s-4k(k+1)} \iff \\ s-4k(k+1)=2(k+1) \iff s=4k(k+1)+2(k+1)=2(k+1)(2k+1)$$ or $$s=\sigma\left(\frac{t(t+1)}{2}\right)=2\cdot\frac{t(t+1)}{2}$$
Proposition 5. $t$ is a Mersenne prime.
From Proposition 1 and 3 $t$ is odd and square free, i.e. its prime factorisation is $t=q_1\cdot q_2\cdot ...\cdot q_r, q_i>2, q_i\ne q_j, i\ne j$. $\sigma(n)$ is multiplicative and $\gcd(t,t+1)=1$ thus $$\sigma\left(\frac{t(t+1)}{2}\right)=\sigma(t)\sigma\left(\frac{t+1}{2}\right)= \sigma\left(\frac{t+1}{2}\right)\prod\limits_{i=1}^r(q_i+1)=2^r\cdot Q$$
• if $r\geq 2$, from $(2)$, $4 \mid (t+1)$ and (from proposition 4) $\frac{t(t+1)}{2}$ is even perfect number, thus $t$ is Mersenne prime.
• if $r=1$, then $t$-is prime and $\varphi(t)=t-1=2k$ and from proposition 2 $$k(k+1)=\varphi(2k+1)\varphi(k+1)=2k\varphi(k+1) \Rightarrow 2\mid k+1=\frac{t+1}{2}$$ and (from proposition 4) $\frac{t(t+1)}{2}$ is even perfect number, thus $t$ is Mersenne prime.
Done. It might be more difficult (if possible at all) to deduct this from individual $(1)$ or $(2)$.
Remark: This book, page 72, has a short proof of
Theorem 1.51. An even positive integer $n$ is perfect if and only if $n = 2^{k−1}M_k$ for some positive integer $k$ for which $M_k$ (Mersenne number) is a prime.
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# “Infinite Steps” [closed]
Three Mathematicians standing on infinite ladder on step number 35, 192, 227 respectively.
Everyone has same two secret formula, based on current standing position(step Number) one of the formula calculates and tell individually a new and distinct step number.
All three Mathematicians have applied formula 13 times and managed to stand on the step number one
Can You Find Which Formulas They Have Used ?
## closed as too broad by Gareth McCaughan♦, Beastly Gerbil, Glorfindel, Sconibulus, greenturtle3141Apr 9 '17 at 16:19
Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.
• I believe this question may have more than one answer. – Oray Apr 9 '17 at 14:36
• What is the source of this puzzle? – Gareth McCaughan Apr 9 '17 at 14:46
• Two secret formulas? So one says what step to stand on next, and the other ... does what? – Gareth McCaughan Apr 9 '17 at 14:48
• @gareth-mccaughan its based on one of the famous mathematical conjecture – Dharmesh Apr 9 '17 at 16:11
• You're probably looking for the Collatz formula. This is still way too broad though - any number of things can be the "applied formula". – Deusovi Apr 9 '17 at 18:36
each mathematician's formula is f(x) = 1. After applying this nine times they are all on step 1. [EDITED to add: when I wrote this, the question said 9 where it now says 13. But of course this answer works just as well with 13 as 9.]
Or, alternatively, we could close the question as too broad.
• f(x)=1 for n steps will surely gives any intended answer, but distinct value at each step which is one of the condition – Dharmesh Apr 16 '17 at 16:08
• Distinct values at each step were not in the conditions when I wrote the answer above. – Gareth McCaughan Apr 17 '17 at 0:09
• It was for the edited comment "But of course this answer works just as well with 13 as 9." – Dharmesh Apr 18 '17 at 11:12
• Ah, OK. Then I didn't notice all the changes that had been made when the puzzle was edited. – Gareth McCaughan Apr 18 '17 at 14:16
I have found an answer but I believe there are more than one answer.
There are two formulas, so the obvious way to use these formulas is standing on an even or odd ladder number. If you are on even ladder, use first formula, otherwise use second formula below.
The formulas are;
1- $n/2+2$ if n is even
and
2- $n+1$ if n is odd
and so the final step number is
6
• This would be one of the possible two formula for given question. can we use/tweak the same formula to take them all till step no #1 – Dharmesh Apr 9 '17 at 16:04
• @Dharmesh you have changed to question a couple of times! (from 9 to 13, from any step no to 1...) – Oray Apr 10 '17 at 14:03
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# Evaluate: (3)/(sqrt(6)-\sqrt{5)}
## Expression: $\frac{ 3 }{ \sqrt{ 6 }-\sqrt{ 5 } }$
Multiply the fraction by $\frac{ \sqrt{ 6 }+\sqrt{ 5 } }{ \sqrt{ 6 }+\sqrt{ 5 } }$
$\frac{ 3 }{ \sqrt{ 6 }-\sqrt{ 5 } } \times \frac{ \sqrt{ 6 }+\sqrt{ 5 } }{ \sqrt{ 6 }+\sqrt{ 5 } }$
To multiply the fractions, multiply the numerators and denominators separately
$\frac{ 3\left( \sqrt{ 6 }+\sqrt{ 5 } \right) }{ \left( \sqrt{ 6 }-\sqrt{ 5 } \right) \times \left( \sqrt{ 6 }+\sqrt{ 5 } \right) }$
Use $\left( a-b \right)\left( a+b \right)={a}^{2}-{b}^{2}$ to simplify the product
$\frac{ 3\left( \sqrt{ 6 }+\sqrt{ 5 } \right) }{ 6-5 }$
Subtract the numbers
$\frac{ 3\left( \sqrt{ 6 }+\sqrt{ 5 } \right) }{ 1 }$
Any expression divided by $1$ remains the same
$3\left( \sqrt{ 6 }+\sqrt{ 5 } \right)$
Distribute $3$ through the parentheses
\begin{align*}&3\sqrt{ 6 }+3\sqrt{ 5 } \\&\approx14.05667\end{align*}
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# For the sequence x[n] = {1, -1, 1, -1}, with n = 0, 1, 2, 3, the DFT is computed as $$X\left( k \right) = \mathop \sum \limits_{n = 0}^3 x\left[ n \right]{e^{ - j\frac{{2\pi }}{4}nk}}$$, for k = 0, 1, 2, 3. The value of k for which X(k) is not zero is
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## Detailed Solution
Analysis:
Given,
x(n) = {1, -1, 1, -1}
$$X\left( k \right) = \mathop \sum \limits_{h = 0}^3 x\left( n \right){e^{ - j}}\frac{{2\pi }}{4}nk$$
We can now write:
$$X\left( 0 \right) = \mathop \sum \limits_{n = 0}^3 x\left( n \right) \cdot 1$$
$$= x\left( 0 \right) + x\left( 1 \right) + x\left( 2 \right) + x\left( 3 \right)$$
X(0) = 0
$$X\left( 1 \right) = \mathop \sum \limits_{n = 0}^3 x\left( n \right){\left( { - j} \right)^n}$$
$$= 1 + j - 1 - j$$
X(1) = 0
$$X\left( 2 \right) = \mathop \sum \limits_{n = 0}^3 x\left( n \right){\left( { - 1} \right)^n}$$
$$= 1 + 1 + 1 + 1$$
X(2) = 4
$$X\left( 3 \right) = \mathop \sum \limits_{n = 0}^3 x\left( n \right){\left( j \right)^n}$$
$$= 1 - j - 1 + j$$
X(3) = 0
Hence,
X(k) = [0, 0, 4, 0]
We observe that the term for k = 2 is not zero.
Short Trick:
X(k) = X* (N – K) where N = 4
x(0) = x(0) + x(1) + x(2) + x(3) = 0
x(N/2) = x(2) = x(0) – x(1) + x(2) – x(3) = 4
Hence for k = 2, X(k) ≠ 0
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### #ActualBacterius
Posted 27 November 2013 - 04:16 AM
If the program knows the password is incorrect before decrypting and decompressing the data, then it means the hashed password is easily accessible - perhaps in the file header? Shouldn't the data be decrypted and decompressed regardless if the password is correct or not, the only difference being an incorrect password will produce a huge pile of garbage? Can someone explain this?
Sure, the hashed password is available. But you can't use it for decryption. Basically it goes like this:
+----------------------------------------------+ +-------------------------------+
| | ONE WAY ONLY | |
| Plain password (typed by the user) | +----------> | Encryption key |
| | | |
+----------------------------------------------+ +-------------------------------+
+
|
| ONE WAY ONLY
|
|
v
+----------------------------------------------+
| |
| Hashed password (useful only for comparison) |
| |
+----------------------------------------------+
The two are unrelated and you can't deduce one from the other. So the hashed password is used to find out if you typed the right password, and then when you did, the program can calculate the encryption key and decrypt the program. That way it can warn you if you typed the wrong password without decrypting garbage, without any security issues. So technically the hashed password isn't "needed", it's a quality of life thing to guarantee that you don't end up decrypting garbage, and also lets you check the key *without* decrypting anything (which is relevant in some cases).
You can also do more advanced stuff with this such as making sure the file was not compromised (modified surreptitiously) etc.. basically it's a useful technique, and does not indicate a security flaw
### #2Bacterius
Posted 27 November 2013 - 04:12 AM
If the program knows the password is incorrect before decrypting and decompressing the data, then it means the hashed password is easily accessible - perhaps in the file header? Shouldn't the data be decrypted and decompressed regardless if the password is correct or not, the only difference being an incorrect password will produce a huge pile of garbage? Can someone explain this?
Sure, the hashed password is available. But you can't use it for decryption. Basically it goes like this:
+----------------------------------------------+ +-------------------------------+
| | ONE WAY ONLY | |
| Plain password (typed by the user) | +----------> | Encryption key |
| | | |
+----------------------------------------------+ +-------------------------------+
+
|
| ONE WAY ONLY
|
|
v
+----------------------------------------------+
| |
| Hashed password (useful only for comparison) |
| |
+----------------------------------------------+
The two are unrelated and you can't deduce one from the other. So the hashed password is used to find out if you typed the right password, and then when you did, the program can calculate the encryption key and decrypt the program. That way it can warn you if you typed the wrong password without decrypting garbage, without any security issues. So technically the hashed password isn't "needed", it's a quality of life thing to guarantee that you don't end up decrypting garbage, and also lets you check the key *without* decrypting anything (which is relevant in some cases).
### #1Bacterius
Posted 27 November 2013 - 04:06 AM
If the program knows the password is incorrect before decrypting and decompressing the data, then it means the hashed password is easily accessible - perhaps in the file header? Shouldn't the data be decrypted and decompressed regardless if the password is correct or not, the only difference being an incorrect password will produce a huge pile of garbage? Can someone explain this?
Sure, the hashed password is available. But you can't use it for decryption. Basically it goes like this:
+----------------------------------------------+ +-------------------------------+
| | ONE WAY ONLY | |
| Plain password (typed by the user) | +----------> | Encryption key |
| | | |
+----------------------------------------------+ +-------------------------------+
+
|
| ONE WAY ONLY
|
|
v
+----------------------------------------------+
| |
| Hashed password (useful only for comparison) |
| |
+----------------------------------------------+
The two are unrelated and you can't deduce one from the other. So the hashed password is used to find out if you typed the right password, and then when you did, the program can calculate the encryption key and decrypt the program. That way it can warn you if you typed the wrong password without decrypting garbage, without any security issues.
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# Problem Of The Week #367 May 22nd, 2019
Status
Not open for further replies.
#### anemone
##### MHB POTW Director
Staff member
Here is this week's POTW:
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Without using a calculator, simplify $$\displaystyle \frac{\displaystyle\sum_{k=1}^{2499}\sqrt{10+{\sqrt{50+\sqrt{k}}}}}{\displaystyle\sum_{k=1}^{2499}\sqrt{10-{\sqrt{50+\sqrt{k}}}}}$$.
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#### anemone
##### MHB POTW Director
Staff member
Hi to all MHB
members!
Despite of the fact that last week's High School's POTW
is more difficult than usual, I am going to give members another week to attempt at a solution!
#### anemone
##### MHB POTW Director
Staff member
No one answered last two week's problem, but you can find the suggested solution as below.
Let the numerator and the denominator be $A$ and $B$ respectively.
Letting $a_k=\sqrt{10+\sqrt{50+\sqrt{k}}}$ and $b_k=\sqrt{10-\sqrt{50+\sqrt{k}}}$, we can represent $A$ and $B$ as
$$\displaystyle A=\sum_{1}^{2499}a_k\\B=\sum_{1}^{2499}b_k$$,
Letting $p_k=\sqrt{50+\sqrt{k}}$ and $q_k=\sqrt{50-\sqrt{k}}$, since $p_k^2+q_k^2=10^2$ and $p_k>0$ and $q_k>0$, there exists a real number $0<x_k<\dfrac{\pi}{2}$ such that
$p_k=10\cos x_k\\q_k=10\sin x_k$
Then, we get
$a_k=\sqrt{10+10cosx_k}=\sqrt{10+10\left(2\cos^2\dfrac{x_k}{2}-1\right)}=\sqrt{20}\cos\dfrac{x_k}{2}$
$b_k=\sqrt{10-10cosx_k}=\sqrt{10-10\left(1-2\sin^2\dfrac{x_k}{2}\right)}=\sqrt{20}\sin\dfrac{x_k}{2}$
\displaystyle \begin{align}a_{2500-k}&=\sqrt{10+\sqrt{50+\sqrt{(50+\sqrt k)(50-\sqrt k)}}}\\&=\sqrt{10+\sqrt{50+{p_kq_k}}}\\&=\sqrt{10+\sqrt{50+100\cos {x_k}\sin {x_k}}}\\&=\sqrt{10+\sqrt{50(\cos {x_k}+\sin {x_k})^2}}\\&=\sqrt{10+\sqrt{50}\cdot\sqrt2\sin \left(x_k+\frac{\pi}{4}\right)}\\&=\sqrt{10+10\cdot2\cos \left(\frac{x_k}{2}+\frac{\pi}{8}\right)\sin \left(\frac{x_k}{2}+\frac{\pi}{8}\right)}\\&=\sqrt{10\left(\cos \left(\frac{x_k}{2}+\frac{\pi}{8}\right)+\sin \left(\frac{x_k}{2}+\frac{\pi}{8}\right)\right)^2}\\&=\sqrt{10}\left(\cos \left(\frac{x_k}{2}+\frac{\pi}{8}\right)+\sin \left(\frac{x_k}{2}+\frac{\pi}{8}\right)\right)\\&=\frac{\left(\cos \left(\frac{\pi}{8}\right)+\sin \left(\frac{\pi}{8}\right)\right)a_k+\left(\cos \left(\frac{\pi}{8}\right)-\sin \left(\frac{\pi}{8}\right)\right)b_k}{\sqrt2}\\&=\sqrt{\frac{\sqrt2+1}{2\sqrt2}}a_k+\sqrt{\frac{\sqrt2-1}{2\sqrt2}}b_k\end{align}
Hence,
$A=\sqrt{\dfrac{\sqrt2+1}{2\sqrt2}}A+\sqrt{\dfrac{\sqrt2-1}{2\sqrt2}}B$
$\dfrac{A}{B}=1+\sqrt{2}+\sqrt{4+2\sqrt{2}}$
or
$$\displaystyle \frac{\displaystyle\sum_{k=1}^{2499}\sqrt{10+{\sqrt{50+\sqrt{k}}}}}{\displaystyle\sum_{k=1}^{2499}\sqrt{10-{\sqrt{50+\sqrt{k}}}}}=1+\sqrt{2}+\sqrt{4+2\sqrt{2}}$$
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Questions & Answers
Question
Answers
# Arun bought a car for Rs. 350,000. The next year, the price went up to Rs. 370,000. What was the percentage of price increased?
Answer Verified
Hint: In this question Arun bought a car for some amount and later after certain duration of time the price of that car went up, so the percentage increase in amount of car will be increment in price divided by original price multiplied with 100 so, use this basic concept to reach the solution of the problem.
Complete step-by-step answer:
Given data
Arun bought a car for Rs. 350,000.
And in the next year, the price went up to Rs. 370,000.
So, increment in the price is $= 370,000 - 350,000 = Rs.{\text{ }}20,000$
So, the percentage of price increased is the ratio of increment in the price divided by original price multiplied by 100.
Therefore percentage of price increased $= \dfrac{{20,000}}{{350,000}} \times 100$
$= \dfrac{2}{{35}} \times 100 = \dfrac{{40}}{7} = 5.714$%
So, this is the required percentage of price increase.
Note: Whenever we face such types of problems the key point to firstly calculate the increment in price, which can be obtained by subtracting the original price from the increased price. After having an incremented price the percentage can be easily calculated using the basic percentage calculation formula.
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# 3.3: Classifying Analytical Techniques
Analyzing a sample generates a chemical or physical signal that is proportional to the amount of analyte in the sample. This signal may be anything we can measure, such as mass or absorbance. It is convenient to divide analytical techniques into two general classes depending on whether the signal is proportional to the mass or moles of analyte, or to the analyte’s concentration.
Consider the two graduated cylinders in Figure $$\PageIndex{1}$$, each containing a solution of 0.010 M $$\ce{Cu(NO_3)_2}$$. Cylinder 1 contains 10 mL, or 1.0 × 10-4 moles of $$\ce{Cu^{2+}}$$, and cylinder 2 contains 20 mL, or 2.0 × 10-4 moles of $$\ce{Cu^{2+}}$$. If a technique responds to the absolute amount of analyte in the sample, then the signal due to the analyte, $$S_\ce{A}$$, is
$S_\ce{A} = k_\ce{A} n_\ce{A} \label{3.1}$
where nA is the moles or grams of analyte in the sample, and kA is a proportionality constant. Since cylinder 2 contains twice as many moles of $$\ce{Cu^{2+}}$$ as cylinder 1, analyzing the contents of cylinder 2 gives a signal that is twice that of cylinder 1.
A second class of analytical techniques are those that respond to the analyte’s concentration, CA
$S_\ce{A} = k_\ce{A}C_\ce{A} \label{3.2}$
Since the solutions in both cylinders have the same concentration of $$\ce{Cu^{2+}}$$, their analysis yields identical signals.
Figure $$\PageIndex{1}$$: Graduated cylinders containing 0.10 M $$\ce{Cu(NO_3)_2}$$. Although the cylinders contain the same concentration of $$\ce{Cu^{2+}}$$, the cylinder on the left contains 1.0 × 10-4 mol $$\ce{Cu^{2+}}$$ and the cylinder on the right contains 2.0 × 10-4 mol $$\ce{Cu^{2+}}$$.
A technique responding to the absolute amount of analyte is a total analysis technique. Mass and volume are the most common signals for a total analysis technique, and the corresponding techniques are gravimetry and titrimetry. With a few exceptions, the signal for a total analysis technique is the result of one or more chemical reactions involving the analyte. These reactions may involve any combination of precipitation, acid–base, complexation, or redox chemistry. The stoichiometry of the reactions determines the value of kA in Equation $$\ref{3.1}$$. Historically, most early analytical methods used a total analysis technique. For this reason, total analysis techniques are often called “classical” techniques.
Spectroscopy and electrochemistry, in which an optical or electrical signal is proportional to the relative amount of analyte in a sample, are examples of concentration techniques. The relationship between the signal and the analyte’s concentration is a theoretical function that depends on experimental conditions and the instrumentation used to measure the signal. For this reason the value of kA in Equation $$\ref{3.2}$$ must be determined experimentally. Since most concentration techniques rely on measuring an optical or electrical signal, they also are known as “instrumental” techniques.
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## Fuel efficiency by Joules
The combustion of 1L of gasoline releases about 3.4*10^7 J of energy. In one car's engine, about 80% of that energy is lost as heat. If the car requires 7.3×10^5J of work to travel 1km , find the fuel efficiency in km/L.
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It honors the spectacle maker and telescope pioneer Zacharias Janssen. The world has at least 82.4 percent (but probably 103 percent) of Jupiter's mass. 55 Cancri d was discovered in 2002.. Discovery. Site Editor: The red dwarf 55 Cancri B is of the 13th magnitude and only visible through a telescope. This innermost planet is … 55 Cancri e, also named Janssen for the inventor of the optical telescope, is in a scorchingly close orbit around a star 40 light-years away. [27], Large surface-temperature variations on 55 Cancri e have been attributed to possible volcanic activity releasing large clouds of dust which blanket the planet and block thermal emissions. 55 Cancri e is also coplanar with b. A bit cooler (5280 Kelvin) and carrying just under a solar mass, it shines at just 58 percent of the luminosity of the Sun, its radius 0.9 solar. The mass of the exoplanet is about 8.08 Earth masses, and its diameter is about twice that of the Earth, thus classifying it as the first super-Earth detected around a main-sequence star, predating Gliese 876 d by nearly a year. Tarf, also designated as β Cancri (beta Cancri), is a variable and double giant star in the constellation of Cancer . 55 Cancri e (abbreviated 55 Cnc e, also named Janssen), is an exoplanet in the orbit of its Sun-like host star 55 Cancri A. Explore an interactive gallery of some of the most intriguing and exotic planets discovered so far. It was announced at the same time as another "hot Neptune" orbiting the red dwarf star Gliese 436 named Gliese 436 b. We can make them in industrial quantities, and those diamonds are practically dirt cheap. The transit shows that its inclination is about 83.4 ± 1.7, so the real mass is close to the minimum. 08 Sep 2004: If coplanarity is assumed with the planet 55 Cnc d, McArthur et al. Its discovery was announced in 2007. & CUTZ M. MNRAS, 496, 4979 paper arxiv. It has a surface temperature of nearly 4,900 degrees Fahrenheit (2,700 degrees Celsius). In 2008, Fischer et al. There are a ton of good reasons as outlined in other answers, but one that most seemed to miss is that diamonds are virtually worthless. ‹ … [5][6], In February 2016, it was announced that NASA's Hubble Space Telescope had detected hydrogen and helium (and suggestions of hydrogen cyanide), but no water vapor, in the atmosphere of 55 Cancri e, the first time the atmosphere of a super-Earth exoplanet was analyzed successfully. 55 Cancri is ’n dubbelster sowat 41 ligjare van die Aarde af in die sterrebeeld Kreef (Cancer). Die stelsel bestaan uit ’n G-tipe hoofreeksster en ’n kleiner rooi dwerg.Hulle is meer as 1 000 AE van mekaar af (duisend keer die afstand tussen die Aarde en die Son). 2004 derive a mass 17.7 ± 5.57 M Earth for the planet 55 Cnc e. Related publications Demonstrating high-precision photometry with a CubeSat: ASTERIA observations of 55 Cancri e The radial velocity method used to detect 55 Cancri e obtains the minimum mass of 7.8 times that of Earth, or 48% of the mass of Neptune. 55 Cancri E is a 'super Earth': a rocky exoplanet about twice the size and eight times the mass of Earth. However, the 2.8-day planet was shown to be an alias by Dawson and Fabrycky (2010); its true period was 0.7365 days. [14], 55 Cancri e receives more radiation than Gliese 436 b. 55 Cancri e, also known as Janssen, orbits a star called Copernicus only 41 light years away. [16] Infrared mapping with the Spitzer Space Telescope indicated an average front-side temperature of 2,573 K (2,300 °C; 4,172 °F) and an average back-side temperature of around 1,644 K (1,371 °C; 2,500 °F). [19] In this case, roughly a third of the planet's mass would be carbon, much of which may be in the form of diamond as a result of the temperatures and pressures in the planet's interior. The discovery of a Neptune-mass planet in an sub-Mercury orbit around nearby Sun-like star 55 Cancri, announced yesterday along with the discovery of other similar systems, gives a new indication that planetary systems as complex as our own Solar System likely exist elsewhere. The 55 Cancri system is located fairly close to the Solar System: the Gaia astrometry satellite measured the parallax of 55 Cancri A as 79.4274 milliarcseconds, corresponding to a distance of 12.59 parsecs (41.06 light years). A limitation of the radial velocity method used to detect 55 Cancri e is that only a minimum mass can be obtained, in this case around 14.2 times that of Earth, or 80% of the mass of Neptune. 55 Cancri b, sometimes called 55 Cancri Ab so to distinguish it from the companion star 55 Cancri B, is the first extrasolar planet discovered orbiting 55 Cancri A in 1996. A so-called super-Earth boasting about twice the Earth’s diameter and eight times Earth’s mass, the “diamond planet,” whose official designation is 55 Cancri e, is the smallest member of a five-planet system located in the constellation Cancer. In 2005, the existence of planet e was questioned by Jack Wisdom in a reanalysis of the data. [3] In October 2012, it was announced that 55 Cancri e could be a carbon planet. Theoretical Studies of Comets in the 55 Cancri System 2020 DVORAK R., LOIBNEGGER B. [13] The transits occur with the period (0.74 days) and phase that had been predicted by Dawson & Fabrycky. 55 Cancri b has a mass around 0.824 that of Jupiter, and is considered a "Hot Jupiter". [28][29], Coordinates: 08h 52m 35.8s, +28° 19′ 51″, Artist's impression of 55 Cancri e near its host star, X-ray and ultraviolet irradiation would destroy it, "Oozing Super-Earth: Images of Alien Planet 55 Cancri e", "First detection of super-earth atmosphere", NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars, Final Results of NameExoWorlds Public Vote Released, 55 Cancri e – Exoplanet Exploration: Planets Beyond our Solar System, Monthly Notices of the Royal Astronomical Society, "NASA Space Telescope Sees the Light from an Alien Super-Earth", "Hint of a transiting extended atmosphere on 55 Cancri b", "Nearby Super-Earth Likely a Diamond Planet", "A Search for Water in a Super-Earth Atmosphere: High-resolution Optical Spectroscopy of 55Cancri e", "High-energy environment of super-Earth 55 Cancri e - I. Far-UV chromospheric variability as a possible tracer of planet-induced coronal rain", "A primeira detecção da composição atmosférica de uma super-Terra", A Case for an Atmosphere on Super-Earth 55 Cancri e - Astrobiology, Lava or Not, Exoplanet 55 Cancri e Likely to have Atmosphere, Astronomers May Have Found Volcanoes 40 Light-Years From Earth, Spitzer Detects a Steaming Super-Earth Eclipsing Its Star, Interactive visualisation of the 55 Cancri system, https://en.wikipedia.org/w/index.php?title=55_Cancri_e&oldid=992798599, Articles with dead external links from June 2020, Articles with permanently dead external links, Short description is different from Wikidata, Articles with unsourced statements from June 2020, Creative Commons Attribution-ShareAlike License, 0.01544 ± 0.00005 AU (2,309,800 ± 7,500 km), 2,709 K (2,436 °C; 4,417 °F) (average maximum), This page was last edited on 7 December 2020, at 04:11. The 55 Cancri System: Fundamental Stellar Parameters, Habitable Zone Planet, and Super-Earth Diameter 2011 von BRAUN K., BOYAJIAN TABETA S., ten BRUMMELAAR T., van BELLE G., KANE S. et al. Application of the Titius-Bode Rule to the 55 Cancri System: … 55 Cancri A is a yellow-orange main sequence dwarf of spectral type G8 V and is the primary star of the system that all known extrasolar worlds in that system orbit. The molten surface is completely uninhabitable, but above the burning horizon, Janssen’s sister planet, Galileo, hangs in a dark sky. 55 Cancri is a visual binary star system in the constellation Cancer consisting of a middle-aged, Sun-like primary of high metallicity, 55 Cancri A, and a red dwarf companion, 55 Cancri B. 55 Cancri e is an extrasolar planet with a mass similar to that of Neptune orbiting the Sun-like star 55 Cancri A.It takes less than three days to complete an orbit and is the innermost known planet in its planetary system. The exotic exoplanet, 55 Cancri e, is over eight times the mass of Earth and has previously been dubbed the ‘diamond planet’ because models based on its mass and radius have led some astronomers to speculate that its interior is carbon-rich. Your system is 55 Cancri. Le système de 55 Cancri est situé à une distance relativement proche du Système solaire : le satellite Hipparcos, lancé par l'Agence spatiale européenne et dédié à l'astrométrie, mesura la parallaxe de 55 Cancri A, l'estimant à 79,80 milliarcsecondes.Cela correspond à une distance de 12,5 parsecs [2].L'étoile 55 Cancri A a une magnitude apparente de +5,95. In 2011, a transit of the planet was confirmed, allowing scientists to calculate its density. Retrieved from "https://astronomical.fandom.com/wiki/55_Cancri_c?oldid=7211" ‹ Back to list 55 Cancri b has a mass of around 0.1714 that of Jupiter. Kristen Walbolt 55 Cancri A has an apparent magnitude of 5.95, making it just visible to the naked eye under very dark skies. 55 Cancri e is also coplanar with b. The transit shows that its inclination is about 83.4 ± 1.7, so the real mass is close to the minimum. 55 Cancri e was discovered on 30 August 2004. Its mass is 8.08 Earths, it takes 0.7 days to complete one orbit of its star, and is 0.01544 AU from its star. The mass of the exoplanet is about 8.08 Earth masses, and its diameter is about twice that of the Earth, thus classifying it as the first super-Earth detected around a main-sequence star, predating Gliese 876 d by nearly a year. [20] Assuming an atmosphere dominated by volcanic species and a large hydrogen component, the heavier molecules could be confined within latitudes < 80° while the volatile hydrogen is not. It is likely a carbon planet. [25][26] Spectroscopic study in 2020 also did not detect hydrogen or helium, indicating the primordial atmosphere is completely lost by now, leaving only secondary atmosphere. Its discovery was announced in 2007. The planet has twice the diameter of Earth and is often referred to as super-Earth. Its mass is 8.08 Earths, it takes 0.7 days to complete one orbit of its star, and is 0.01544 AU from its star. It is faint to the naked eye. 55 Cancri b (abbreviated as "55 Cnc b"), and sometimes designated as 55 Cancri Ab, is an extrasolar planet orbiting the Sun-like star 55 Cancri A.It is around 40 light years away from Earth.The planet is a good example of a Hot Jupiter.. Characteristics Edit. Silicates in the atmosphere would condense into clouds on the tidally-locked planet's darkside reflecting the lava below. 55 Cancri is a visual binary star system in the constellation Cancer consisting of a middle-aged, Sun-like primary of high metallicity, 55 Cancri A, and a red dwarf companion, 55 Cancri B. 55 Cancri E, discovered in 2004, has a mass 8.3 times the mass of Earth and an orbital period of 0.74 days. With that knowledge in mind, now picture a third of that mass … Finally, our direct value for 55 Cancri's stellar radius allows for a model-independent calculation of the physical diameter of the transiting super-Earth 55 Cnc e ($\sim 2.05 \pm 0.15 R_{\earth}$), which, depending on the planetary mass assumed, implies a bulk density of 0.76 $\rho_{\earth}$ or 1.07 $\rho_{\earth}$. The mass of the exoplanet is about 8.63 Earth masses and its diameter is about twice that of the Earth, thus classifying it as the first super-Earth discovered around a main sequence star, predating Gliese 876 d by a year. 55 Cancri f is located about 0.781 AU away from the star and takes 260 days to complete a full orbit. [citation needed], It was initially unknown whether 55 Cancri e was a small gas giant like Neptune or a large rocky terrestrial planet. [8] The process involved public nomination and voting for the new names. 55 Cancri e, formellement 55 Cancri Ae, également appelée Rho 1 Cancri (A)e, HD 75732 (A)e ou encore Janssen depuis décembre 2015, est une planète extrasolaire (exoplanète) en orbite autour de l'étoile 55 Cancri A, une naine jaune située à une distance d'environ 40 années-lumière du Soleil, dans la constellation zodiacale du Cancer. 55 Cancri là một hệ sao đôi cách Mặt Trời 41 năm ánh sáng trong chòm sao cung hoàng đạo Cancri. The planet completes an orbit around its host star in about 44 days. It is the second planet in order of distance from its star, and is an example of a hot Jupiter, or possibly rather "warm Jupiter". The planet's orbit is fairly eccentric, a result of interactions with the nearby Jupiter-mass planet 55 Cancri b which prevent tidal forcesfrom circularising the orbit. 55 Cancri e is a super-Earth exoplanet that orbits a G-type star similar to our Sun. Like the majority of known extrasolar planets, 55 Cancri e was discovered by detecting variations in its star's radial velocity. Its discovery was announced in 2004. 55 Cancri e is a planet that is partially made of diamonds. Anya Biferno. 55 Cancri e (abbreviated 55 Cnc e, also named Janssen), is an exoplanet in the orbit of its Sun-like host star 55 Cancri A.The mass of the exoplanet is about 8.63 Earth masses and its diameter is about twice that of the Earth, thus classifying it as the first super-Earth discovered around a main sequence star, predating Gliese 876 d by a year. 55 Cancri e (abbreviated 55 Cnc e, also named Janssen), is an exoplanet in the orbit of its Sun-like host star 55 Cancri A. Science Writer: Its mass is 8.63 Earths and its radius is 2 Earths. 55 Cancri f is a gas giant exoplanet that orbits a K-type star. Despite their … Tarf / Beta Cancri is the brightest star in the zodiacal constellation of Cancer, the celestial crab. The planet completes an orbit with 55 Cancri in just 14 days, and it orbits very closely to its host star, though not as extreme as 51 Pegasi b. He suggested that the 2.8-day planet was an alias and, separately, that there was a 260-day planet in orbit around 55 Cancri. 55 Cancri (55 Cnc), aussi nommée Rho 1 Cancri, est une étoile binaire située à une distance d'environ ∼40 a.l. 55 Cancri A has around 95 percent of the Sun's mass, 1.1 times its diameter, but is only around 60 percent as luminous. It has a surface temperature of nearly 4,900 degrees Fahrenheit (2,700 degrees Celsius). 55 Cancri f is a gas giant exoplanet that orbits a K-type star. 55 Cancri b has a mass of around 0.1714 that of Jupiter. Tarf is also orbited by an exoplanet, which was discovered in 2014.This massive planet has a minimum mass of around 7.8 times that of Jupiter, and an orbital period of 705 days.. The planet is orbiting a sun-like star located 40 light years away. 55 Cancri e is a super-Earth — about twice our planet's size — that zooms around its star in 18 days. This star is known to possess (at least) five planets with masses ranging between super-Earth and Jupiter-type. [9] In December 2015, the IAU announced the winning name was Janssen for this planet. Sedert 2011 is vyf planete bevestig wat om die hoofster, 55 Cancri A (die geel dwerg), wentel. 55 Cancri e is located in a very close orbit around the star which takes less than three days to complete and falls into the category of "hot Neptunes". Discovery. [7], In July 2014 the International Astronomical Union (IAU) launched a process for giving proper names to certain exoplanets and their host stars.
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# Bibcode(Redirected from Bibcode (identifier))
Full name Bibliographic code 1990s 19 none 1924MNRAS..84..308E
The bibcode (also known as the refcode) is a compact identifier used by several astronomical data systems to uniquely specify literature references.
The Bibliographic Reference Code (refcode) was originally developed to be used in SIMBAD and the NASA/IPAC Extragalactic Database (NED), but it became a de facto standard and is now used more widely, for example, by the NASA Astrophysics Data System, which coined and prefers the term "bibcode".
## Format
The code has a fixed length of 19 characters and has the form
YYYYJJJJJVVVVMPPPPA
where YYYY is the four-digit year of the reference and JJJJJ is a code indicating where the reference was published. In the case of a journal reference, VVVV is the volume number, M indicates the section of the journal where the reference was published (e.g., L for a letters section), PPPP gives the starting page number, and A is the first letter of the last name of the first author. Periods (.) are used to fill unused fields and to pad fields out to their fixed length if too short; padding is done on the right for the publication code and on the left for the volume number and page number. Page numbers greater than 9999 are continued in the M column. The 6-digit article ID numbers (in lieu of page numbers) used by the Physical Review publications since the late 1990s are treated as follows: The first two digits of the article ID, corresponding to the issue number, are converted to a lower-case letter (01 = a, etc.) and inserted into column M. The remaining four digits are used in the page field.
## Examples
Some examples of bibcodes are:
Bibcode Reference
1974AJ.....79..819H Heintz, W. D. (1974). "Astrometric study of four visual binaries". The Astronomical Journal. 79: 819–825. Bibcode:1974AJ.....79..819H. doi:10.1086/111614.
1924MNRAS..84..308E Eddington, A. S. (1924). "On the relation between the masses and luminosities of the stars". Monthly Notices of the Royal Astronomical Society. 84 (5): 308–332. Bibcode:1924MNRAS..84..308E. doi:10.1093/mnras/84.5.308.
1970ApJ...161L..77K Kemp, J. C.; Swedlund, J. B.; Landstreet, J. D.; Angel, J. R. P. (1970). "Discovery of circularly polarized light from a white dwarf". The Astrophysical Journal Letters. 161: L77–L79. Bibcode:1970ApJ...161L..77K. doi:10.1086/180574.
2004PhRvL..93o0801M Mukherjee, M.; Kellerbauer, A.; Beck, D.; et al. (2004). "The Mass of 22Mg" (PDF). Physical Review Letters. 93 (15): 150801. Bibcode:2004PhRvL..93o0801M. doi:10.1103/PhysRevLett.93.150801. PMID 15524861.
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# Bullet and pendulum bob initial speed help! momentum.
bullet and pendulum bob....initial speed...help! momentum.
## Homework Statement
An 7.0 g bullet is fired into a 3.5 kg pendulum bob initially at rest and becomes embedded in it. If the pendulum rises a vertical distance of 8.0 cm, calculate the initial speed of the bullet.
________m/s
## Homework Equations
well there's many ways to do it, but heres one way:
v=sqrt((1+M/m)*2gh)
i tried it another way too, and got the same answer that i did with the above equation
## The Attempt at a Solution
so first, 7g bullet = .007kg bullet and height of 8cm = .08m
ok so then v=sqrt((1+3.5/.007)*2*9.8*.08) = ~28.03 m/s
now, i tried this TWO WAYS and got the same answer.
but webassign says it's wrong.
why?
Related Introductory Physics Homework Help News on Phys.org
Kurdt
Staff Emeritus
Gold Member
The velocity of the pendulum and the bullet is given by:
$$v=\sqrt{2gh}$$
The mass shouldn't enter into that part. Once v is known one can use the conservation of momentum to find the bullets initial speed.
EDIT: I see what you've done to include the mass. The problem is the mass part should be outside the square root.
The velocity of the pendulum and the bullet is given by:
$$v=\sqrt{2gh}$$
The mass shouldn't enter into that part. Once v is known one can use the conservation of momentum to find the bullets initial speed.
EDIT: I see what you've done to include the mass. The problem is the mass part should be outside the square root.
which mass are you talking about?
Kurdt
Staff Emeritus
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# Semantic issues with predictions made by my trained model
I'm new to Deep Learning. I used Keras and trained a inception_resnet_v2 model for my binary classification application (fire detection). As suggested from my previous question of a non-X class, I prepared a dataset of 8000 images of fire, and a larger dataset for non-fire (20,000 random images) to make sure the network also sees images of non-fire to perform classification.
I trained the model, but now when trying to load the model and pass images of fire and non-fire ones, it shows same result for all of them:
[[0. 1.]]
[[0. 1.]]
[[0. 1.]]
[[0. 1.]]
[[0. 1.]]
What is going wrong? Am I doing anything wrong? Should I get the result another way?
===============================================
I know it's not SO, but this is my prediction code in case it matters:
from __future__ import print_function
import cv2, os, glob
import numpy as np
from keras.preprocessing import image
if __name__ == '__main__':
os.chdir("test")
for file in glob.glob("*.jpg"):
img_path = file
x = image.img_to_array(img)
x = np.expand_dims(x, axis=0)
dictionary = {0: 'non-fire', 1: 'fire'}
results = model.predict(x)
print(results)
predicted_class= np.argmax(results)
acc = 100*results[0][predicted_class]
print("Network prediction is: file: "+ file+", "+dictionary[predicted_class]+", %{:0.2f}".format(acc))
And here is the training:
from keras.applications.inception_resnet_v2 import InceptionResNetV2, preprocess_input
from keras.preprocessing.image import ImageDataGenerator
from keras.layers import Dense, Activation, Flatten, Dropout
from keras.models import Sequential, Model
from keras.callbacks import ModelCheckpoint
from keras.metrics import binary_accuracy
import os
import json
#==========================
HEIGHT = 300
WIDTH = 300
TRAIN_DIR = "data"
BATCH_SIZE = 8 #8
steps_per_epoch = 1000 #1000
NUM_EPOCHS = 50 #50
lr= 0.00001
#==========================
FC_LAYERS = [1024, 1024]
dropout = 0.5
def build_finetune_model(base_model, dropout, fc_layers, num_classes):
for layer in base_model.layers:
layer.trainable = False
x = base_model.output
x = Flatten()(x)
for fc in fc_layers:
# New FC layer, random init
x = Dense(fc, activation='relu')(x)
x = Dropout(dropout)(x)
# New layer
predictions = Dense(num_classes, activation='sigmoid')(x)
finetune_model = Model(inputs=base_model.input, outputs=predictions)
return finetune_model
train_datagen = ImageDataGenerator(preprocessing_function=preprocess_input, rotation_range=90, horizontal_flip=True, vertical_flip=True
,validation_split=0.2)
train_generator = train_datagen.flow_from_directory(TRAIN_DIR, target_size=(HEIGHT, WIDTH), batch_size=BATCH_SIZE
,subset="training")
#split validation manually
validation_generator = train_datagen.flow_from_directory(TRAIN_DIR, target_size=(HEIGHT, WIDTH), batch_size=BATCH_SIZE,subset="validation")
base_model = InceptionResNetV2(weights='imagenet', include_top=False, input_shape=(HEIGHT, WIDTH, 3))
root=TRAIN_DIR
class_list = [ item for item in os.listdir(root) if os.path.isdir(os.path.join(root, item)) ]
print ("class_list: "+str(class_list))
finetune_model = build_finetune_model(base_model, dropout=dropout, fc_layers=FC_LAYERS, num_classes=len(class_list))
# change to categorical_crossentropy for multiple classes
filepath="./checkpoints/" + "Resnet_{epoch:02d}_{acc:.2f}" +"_model_weights.h5"
checkpoint = ModelCheckpoint(filepath, monitor=["val_accuracy"], verbose=1, mode='max', save_weights_only=False)
callbacks_list = [checkpoint]
history = finetune_model.fit_generator(train_generator, epochs=NUM_EPOCHS, workers=BATCH_SIZE,
validation_data=validation_generator, validation_steps = validation_generator.samples,
steps_per_epoch=steps_per_epoch,
shuffle=True, callbacks=callbacks_list)
I think you may have a class imbalance problem here, if I am reading your output correctly. You have 20,000 negative examples, but only 8000 positive ones, and you are minimizing binary cross entropy without re-weighting the examples, so your model can achieve a low-ish loss just by consistently outputing a value close to 0. This forms a local optima in the search space for the model.
To fix this, you could try to optimize some other loss function that is more sensitive to class imbalances, or, likely more productively, you could just use an equal number of examples for each class.
• I've seen examples (cat vs non-cat) where they used 5K for non-cats and 1600 for cats. But what combo of activation/loss shall I use? Is it OK to change the sigmoid to softmax and still have the binary_crossentropy? (like the cat exmaple). Nov 19 '19 at 3:20
• @TinaJ whether you can handle class imbalance will really depend on the problem you are working on. If the classes are difficult to separate, then it will be a problem. If not, it probably won't be. I think the choice of activation function shouldn't make a big difference here. Nov 19 '19 at 3:27
• My impression was the more non-object I have, the better the accuracy. Didn't know the size imbalance can also be a negative factor! Nov 19 '19 at 3:31
• @TinaJ an extreme case that might help with the intuition: Imagine we have a dataset of blood test results, where 99.99% of the results are negative for a disease, and 0.01% are positive. A model can achieve an extremely low cross-entropy loss value by claiming everything is negative. It will be right almost always, but the model is not a useful one. Nov 19 '19 at 3:34
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Séminaire Géométrie et groupes discrets
# Rational Approximations to Linear Subspaces
## by Nicolas de Saxcé (CNRS & Université Paris-Nord)
Europe/Paris
Amphithéâtre Léon Motchane (IHES)
### Amphithéâtre Léon Motchane
#### IHES
Le Bois Marie 35, route de Chartres 91440 Bures-sur-Yvette
Description
Dirichlet's theorem in Diophantine approximation implies that for any real x, there exists a rational p/q arbitrarily close to x such that |x-p/q| < 1/q2. In addition, the exponent 2 that appears in this inequality is optimal, as seen for example by taking $x=\sqrt2$. In 1967, Wolfgang Schmidt suggested a similar problem, where x is a real subspace of Rd of dimension ℓ, which one seeks to approximate by a rational subspace v. Our goal will be to obtain the optimal value of the exponent in the analogue of Dirichlet's theorem within this framework. The proof is based on a study of diagonal orbits in the space of lattices in Rd.
Organized by
Fanny Kassel
Contact
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Question
Space probes may be separated from their launchers by exploding bolts. (They bolt away from one another.) Suppose a 4800-kg satellite uses this method to separate from the 1500-kg remains of its launcher, and that 5000 J of kinetic energy is supplied to the two parts. What are their subsequent velocities using the frame of reference in which they were at rest before separation?
$v_1 = 0.704 \textrm{ m/s}$
$v_2 = -2.25 \textrm{ m/s}$
Solution Video
# OpenStax College Physics Solution, Chapter 8, Problem 37 (Problems & Exercises) (7:26)
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## Calculator Screenshots
Video Transcript
This is College Physics Answers with Shaun Dychko. This satellite here labeled m two and its launcher labeled m one, are connected with exploding bolts. We're going to consider this problem in the reference frame of the satellite launcher which means that initially there is zero velocity. Then sometime later the bolts will explode and that's going to send the satellite to the right and the launcher to the left. The velocities will be such that the total momentum of each of these pieces is going to equal zero because it had zero momentum to begin with. That is what we say in this first line right here. So the launcher mass is 1,500 kilograms, the satellite mass is 4,800 kilograms and we're told that the total kinetic energy of these two pieces after the explosion of the bolt is 5,000 joules. So, we're going to write down our conservation of momentum formula first. The total momentum of each of the pieces after the explosion equals the total momentum initially which is zero and we'll write down that the total kinetic energy is 5,000 after the explosion. We say that by writing one half m one v one prime squared, plus one half m two v two prime squared is 5000. So we have a system of equations and two unknowns. So it's a good thing we have two equations because that's the number of equations you need to solve for two unknown variables. So we're going to do some algebra to combine these equations to solve for them. Let's rearrange equation one and we're going to solve it for v one prime squared, and I did that because in equation two we have a v one prime squared. So we're going to create two equations for v one prime squared and once we do that we can equate those two things together and it will have only one variable, v two prime squared. We'll see that in a second. So equation one is, well we take this to the right hand side by subtracting it from both sides and by the way, this should be a minus there. Actually, not necessarily. I did two things at once here actually. When you move it to the right hand side, sure it gets a minus but then I squared both sides and so the minus disappears because negative m two v two prime times negative m two v two prime is positive m two squared v two prime squared. So this is correct. Then we divide both sides by m one squared there to solve for v one prime squared. Okay. That gives us this line and we cannot go any further than that. But we can turn our attention instead to equation two, the kinetic energy formula and rearrange that to solve for v one prime squared also. So I multiplied everything by two on both sides and the one halves canceled from the two terms on the left. Then the 5,000 joules becomes 10,000 joules and then I also moved this term to the right hand side by subtracting it from both sides. So that's negative m two v two prime squared is on the right side now. Then divide both sides by m one. We have v one prime squared is 10,000 joules minus m two v two prime squared divide by m one. So we have two expressions for v one prime squared and so that means these two things are equal to each other. We can say that equation one b is equal to equation to equation two b. So we can equate the right sides. We have m two squared over m one squared times v two prime squared from equation one b equals 10,000 joules minus m two v two prime squared over m one because each of these things is equal to v one prime squared. Now we're going to solve for v two prime. First of all, we'll -- what do we do first here? I multiplied everything by m one first, that's what I did, and then that makes the denominator here m one to the power one. I canceled the m one there and then this term, you can add it to both sides, plus m two v two prime squared and then add it to this side as well. Then it disappears on the right side and appears on the left. That equals 10,000. Then we factor out the v two prime squared and then also multiply this term by m one over m one which we're allowed to do since m one over m one is the number one. You can multiply anything you like by one without changing its value, but we did it in order to change the way this looks so that we have a common denominator. I think that just looks nicer. So we have m two squared plus m one m two all over m one, multiplied by v two prime squared. Then multiply both sides by the reciprocal of that factor so multiply by m one over m twosquared plus m one m two and do the same to the right side so that the equation stays balanced. Then we have this line here, v two prime squared is 10,000 times m one all over m two squared plus m one m two. Then take the square root of both sides. We get v two prime now, is equal to the square root of m one times 10,000 joules over m two squared plus m one m two. This is 1,500 kilograms times 10,000 joules divided by 4,800 kilograms squared, plus 1,500 kilograms times 4,800 kilograms. This gives 0.704 meters per second. So there we have solved for the velocity of the satellite. The velocity of the launcher, well, we get to that next. We have this equation here. From this conservation of momentum, actually, let's just look at this. From this conservation of momentum we can say that v one prime is negative m two v two prime over m one where I took this term to the right hand side and then divided both sides bym one. So that's what we're going to use to find v one prime because we now know v two prime. So that's what we do here. So v one prime is negative m two over m one times v two prime. So that's negative 4,800 kilograms divided by 1,500 kilograms times 0.704295 meters per second, including lots of digits there to avoid intermediate rounding error. We end up with negative 2.25 meters per second. This is negative because the launcher is moving to the left and we took right to be the positive direction.
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# How quickly will gradient descent converge given only a single training example for a regression problem?
This scenario is mostly academic or of conceptual interest. It might not make much sense in real life.
Consider the case when we are trying to learn a regression function via gradient descent. Say we are doing this by minimizing the training error:
$$H[f] = \sum^N_{n=1} (y_n - f(x_n))^2$$
(or if you want the regularized version of it $\lambda \| f\|^2_2$).
Consider the case where we only have a single training example $(x,y)$.
If updated the coefficient parameters $\theta$ of $f$ via gradient descent:
$$\theta := \theta - \gamma \frac{\partial H[f] }{\partial \theta_i}$$
then how many iterations would it take to converge to a minimum? How long would it take for $\frac{\partial H[f] }{\partial \theta_i}$ to be zero and stop updating the parameters?
The reason I am asking this is because conceptually, say that I asked the same question but for the perceptron algorithm. The perceptron algorithm would start pointing towards the labeled point immediately, hence, it would converge in 1 step. However, it seems less obvious how to reason about this in the case of regression and gradient descent. What are people's thoughts? Would it ever be the case the the gradient is zero after some number of iterations?
Would this question have different answers if we use regularized least squares or only least squares?
What I think is that because we dont have many "conflicting" points of view of what the output of f should be, it would probably converge in very few iterations with only one example.
I know generalization might not be good but I am just trying to understand gradient descent from a conceptual stand point rather than actually use this to predict stuff.
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## Seminars and Colloquia by Series
Thursday, October 31, 2013 - 15:35 , Location: Skiles 006 , , MPI Bonn and MIT , , Organizer: Stavros Garoufalidis
The (blobbed) topological recursion is a recursive structure which defines, for any initial datagiven by symmetric holomorphic 1-form \phi_{0,1}(z) and 2-form \phi_{0,2}(z_1,z_2) (and symmetricn-forms \phi_{g,n} for n >=1 and g >=0), a sequence of symmetric meromorphic n-forms\omega_{g,n}(z_1,...,z_n) by a recursive formula on 2g - 2 + n.If we choose the initial data in various ways, \omega_{g,n} computes interesting quantities. A mainexample of application is that this topological recursion computes the asymptotic expansion ofhermitian matrix integrals. In this talk, matrix models with also serve as an illustration of thisgeneral structure.
Thursday, October 3, 2013 - 15:30 , Location: Skiles 006 , Roger Nichols , University of Tennessee, Chattanooga , , Organizer:
Following Kato, we define the sum, $H=H_0+V$, of two linear operators, $H_0$ and $V$, in a fixed Hilbert space in terms of its resolvent. In an abstract theorem, we present conditions on $V$ that guarantee $\text{dom}(H_0^{1/2})=\text{dom}(H^{1/2})$ (under certain sectorality assumptions on $H_0$ and $H$). Concrete applications to non-self-adjoint Schr\"{o}dinger-type operators--including additive perturbations of uniformly elliptic divergence form partial differential operators by singular complex potentials on domains--where application of the abstract theorem yields $\text{dom}(H^{1/2})=\text{dom}((H^{\ast})^{1/2})$, will be presented. This is based on joint work with Fritz Gesztesy and Steve Hofmann.
Friday, September 27, 2013 - 16:00 , Location: Skiles 006 , , UNC Charlotte , , Organizer:
The talk will present several recent results on the singular and pure point spectra for the (random or non-random) Schrӧdinger operators on the graphs or the Riemannian manifolds of the “small dimensions”. The common feature of all these results is the existence in the potential of the infinite system of the “bad conducting blocks”, for instance, the increasing potential barriers (non-percolating potentials). The central idea of such results goes to the classical paper by Simon and Spencer. The particular examples will include the random Schrӧdinger operators in the tube (or the surface of the cylinder), Sierpinski lattice etc.
Thursday, September 19, 2013 - 16:00 , Location: Skiles 006 , Ranjini Vaidyanathan , Georgia Tech , , Organizer:
We consider a model of randomly colliding particles interacting with a thermal bath. Collisions between particles are modeled via the Kac master equation while the thermostat is seen as an infinite gas at thermal equilibrium at inverse temperature \beta. The system admits the canonical distribution at inverse temperature \beta as the unique equilibrium state. We prove that the any initial distribution approaches the equilibrium distribution exponentially fast both by computing the gap of the generator of the evolution, in a proper function space, as well as by proving exponential decay in relative entropy. We also show that the evolution propagates chaos and that the one-particle marginal, in the large system limit, satisfies an effective Boltzmann-type equation. This is joint work with Federico Bonetto and Michael Loss.
Friday, April 19, 2013 - 15:00 , Location: Skiles 006 , , Université François Rabelais, Tours, France , , Organizer:
El Soufi will be visiting Harrell for the week leading up to this seminar
We shall survey some of the classical and recent results giving upper bounds of the eigenvalues of the Laplace-Beltrami operator on a compact Riemannian manifold (Yang-Yau, Korevaar, Grigor'yan-Netrusov-Yau, etc.). Then we discuss extensions of these results to the eigenvalues of Witten Laplacians associated to weighted volume measures and investigate bounds of these eigenvalues in terms of suitable norms of the weights.
Friday, April 12, 2013 - 15:05 , Location: Skiles 006 , Vieri Mastropietro , Università degli Studi di Milano , Organizer: Federico Bonetto
Several low dimensional interacting fermionic systems, including g raphene and spin chains, exhibit remarkable universality properties in the c onductivity, which can be rigorously established under certain conditions by combining Renormal ization Group methods with Ward Identities.
Wednesday, April 10, 2013 - 14:00 , Location: Skiles 005 , Jacopo de Simoi , Universita' di Roma Tor Vergata , Organizer: Federico Bonetto
Lots of attention and research activity has been devoted to partially hyperbolic dynamical systems and their perturbations in the past few decades; however, the main emphasis has been on features such as stable ergodicity and accessibility rather than stronger statistical properties such as existence of SRB measures and exponential decay of correlations. In fact, these properties have been previously proved under some specific conditions (e.g. Anosov flows, skew products) which, in particular, do not persist under perturbations. In this talk, we will construct an open (and thus stable for perturbations) class of partially hyperbolic smooth local diffeomorphisms of the two-torus which admit a unique SRB measure satisfying exponential decay of correlations for Hölder observables. This is joint work with C. Liverani
Friday, April 5, 2013 - 15:05 , Location: Skiles 006 , Pierluigi Falco , California State University, Northridge , Organizer: Federico Bonetto
The lattice, two dimensional, Coulomb gas is the prototypical model of Statistical Mechanics displaying the 'Kosterlitz-Thouless' phase transition. In this seminar I will discuss conjectures, results and works in progress about this model.
Friday, March 29, 2013 - 15:00 , Location: Skiles 006 , Nikolai Chernov , UAB , Organizer: Federico Bonetto
We study a gas of N hard disks in a box with semi-periodic boundary conditions. The unperturbed gas is hyperbolic and ergodic (these facts are proved for N=2 and expected to be true for all N>2). We study various perturbations by "twisting" the outgoing velocity at collisions with the walls. We show that the dynamics tends to collapse to various stable regimes, however we define the perturbations and however small they are.
Friday, March 8, 2013 - 15:00 , Location: Skiles 006 , , P. Universidad Católica de Chile , , Organizer:
In this talk I will discuss a family of lower bounds on the indirect Coulomb energy for atomic and molecular systems in two dimensions in terms of a functional of the single particle density with gradient correction terms
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# Solution for A 5 Percent Fall in the Price of a Good Raises Its Demand from 300 Units to 318 Units. Calculate Its Price Elasticity of Demand. - CBSE (Arts) Class 12 - Economics
ConceptFactors Affecting Price Elasticity of Demand
#### Question
A 5 percent fall in the price of a good raises its demand from 300 units to 318 units. Calculate its price elasticity of demand.
#### Solution
Given, the initial quantity Q1 = 300
New quantity Q2 = 318
So, ΔQ = 310 - 300 = 18
Now, percentage fall in price =(ΔP)/Pxx100 = (-)5%
We know,
E_d=(-)((ΔQ)/Qxx100)/((ΔP)/Pxx100)=(-)(18/300xx100)/((-)5)=(-) 6/((-)5)=1.2
Thus, price elasticity of demand is 1.2
Is there an error in this question or solution?
#### APPEARS IN
Solution for question: A 5 Percent Fall in the Price of a Good Raises Its Demand from 300 Units to 318 Units. Calculate Its Price Elasticity of Demand. concept: Factors Affecting Price Elasticity of Demand. For the courses CBSE (Arts), CBSE (Commerce)
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# How much hydrogen has been consumed?
1. Jun 22, 2012
### iced199
With our stars consuming hydrogen to make helium, how much has been consumed since the Big Bang? I know 73 or so percent of the total mass of the visible universe is hydrogen, so how much has been consumed? IE, what was the original proportion of hydrogen to helium to other elements? I know we are not in any danger of stars using up all our hydrogen in the near future, but still, just curious. Thanks.
2. Jun 22, 2012
### marcus
I don't have any very precise figures, maybe someone can supply some more accurate.
I think there is rough agreement on the primordial abundances.
In mass terms:
"Without major changes to the Big Bang theory itself, BBN will result in mass abundances of about 75% of H-1, about 25% helium-4, about 0.01% of deuterium..."
http://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis
As I recall the mass abundance of hydrogen is STILL around 73 or 74%. So a vague qualitative assessment would be that not very much has been used up. There are still these big clouds of gas (mostly hydrogen) which haven't even formed stars yet.
And fusion only occurs in the inner cores of stars, so even in stars a lot of the hydrogen is just sitting around in the outer layers providing weight to squeeze the inner 10% core so there is enough density and temperature to support fusion.
I'll try to find a more precise reliable source, but in the meantime my guess would be that percentagewise we have hardly made a dent--probably no more than 1 or 2% of the original hydrogen has been used up. Possibly more but I doubt it. Have to check
Last edited: Jun 22, 2012
3. Jun 22, 2012
### Chronos
It is believed that about 90% of the baryons expected to exist are unaccounted for in the local universe (z~0). That leaves a lot more hydrogen available for future star formation than the amount currently claimed by stars. It is likely much of this exists in the IGM and is mostly ionized, making it difficult to detect. An enormous mass of hydrogen was recently detected bridging Andromeda and the Triangulum galaxy [possibly on the order of 500 million or more solar masses]. See http://arxiv.org/abs/1205.5235
4. Jun 22, 2012
### Orion1
The Universe is capable of burning both hydrogen and helium as nuclear fuel. In about 5 billion years, the Sun will enter a red giant phase and begin burning helium in the core.
λCDM Universe heavy baryonic matter and neutrino density:
$$\Omega_h = 0.0033$$
λCDM Universe baryon density:
$$\Omega_b = 0.0456$$
Percentage of hydrogen and helium burned into heavy baryonic matter by the Universe:
$$P_u = \frac{\Omega_h}{\Omega_b} = 0.0723 = 7.23 \; \%$$
$$\boxed{P_u = 7.23 \; \%}$$
$$P_u = \frac{\Omega_h}{10 \cdot \Omega_b} = 0.00723 = 0.723 \; \%$$
$$\boxed{P_u = 0.723 \; \%}$$
Reference:
λCDM model parameters - Wikipedia
Sun - Possible long-term cycle - Wikipedia
Universe - size, age, structure, and laws - Wikipedia
The End of Stars? - Orion1 #8
Last edited: Jun 23, 2012
5. Jun 23, 2012
### Chalnoth
Where are you getting $\Omega_h$ from? Because these numbers seem extremely unlikely. I don't think that much matter has even collapsed to form stars yet.
6. Jun 23, 2012
### jimgraber
7. Jun 24, 2012
### Orion1
$\Omega_h$ is cited from post#4, reference 3. Only around 0.5% of all 'baryonic' matter is presently in the form of stars, relative to all matter and energy in the total Universe.
Heavy Elements: (baryonic)
$$\Omega_H = 0.003 = 0.3 \; \%$$
Neutrinos: (baryonic)
$$\Omega_{\nu} = 0.0003 = 0.03 \; \%$$
$\Omega_h$ is actually the addition of:
$$\Omega_h = \Omega_H + \Omega_{\nu} = 0.003 + 0.0003 = 0.0033 = 0.33 \; \%$$
$$\boxed{\Omega_h = 0.0033}$$
2% is relative to the Milky Way galaxy's disk, not to the Universe as a whole.
My calculation in post#4 is relative only to 'baryonic' matter in the λCDM model, i.e. hydrogen and helium, and not to all the matter and energy in the total Universe.
Reference:
Universe - size, age, structure, and laws - Wikipedia
Abundance of elements in the Universe - Wikipedia
Last edited: Jun 24, 2012
8. Jun 24, 2012
### Chalnoth
Perhaps you mean from this graph?
http://en.wikipedia.org/wiki/File:Cosmological_Composition_-_Pie_Chart.png
This shows heavy elements as 0.03% of the universe by mass, which is roughly 1% of the total baryon fraction. The neutrino mass fraction almost entirely comes from the early universe, and shouldn't be added here.
9. Jun 24, 2012
### Orion1
λCDM Universe heavy baryonic matter mass fraction:
$$\Omega_h = 0.0003$$
λCDM Universe baryon matter mass fraction:
$$\Omega_b = 0.0456$$
λCDM Universe neutrino baryonic matter mass fraction:
$$\Omega_{\nu} = 0.003$$
λCDM percentage of hydrogen and helium burned into heavy baryonic matter by the Universe:
$$P_u = \frac{\Omega_h}{\Omega_b - \Omega_{\nu}} = 0.00704 = 0.704 \; \%$$
$$\boxed{P_u = 0.704 \; \%}$$
Reference:
Cosmological Composition - Pie_Chart - Wikipedia
λCDM model parameters - Wikipedia
Last edited: Jun 25, 2012
10. Jun 24, 2012
### Chalnoth
Yes, but that number is completely inconsequential compared to either the current heavy baryonic matter density or the primordial neutrino fraction.
Heavy baryonic matter density is roughly $\Omega_H = 0.0003$, a factor of ten less than you paint here.
11. Jun 25, 2012
### Orion1
Corrected, see post#9.
12. Jun 25, 2012
### Chalnoth
Yeah, that's much more reasonable. However, you still shouldn't be considering the neutrino fraction, as that really doesn't have anything to do with the elements being burned in stars, nor is it part of the baryon fraction. There's also too many significant digits kept, as the heavy element fraction is only quoted with one significant digit. So given the information presented so far in this thread, "a bit less than 1%," is the accurate way to state the fraction of baryons in heavy matter by mass.
13. Jun 25, 2012
### Orion1
λCDM Universe heavy baryonic matter mass fraction:
$$\Omega_h = 0.0003$$
λCDM Universe baryon matter mass fraction:
$$\Omega_b = 0.0456$$
λCDM percentage of hydrogen and helium burned into heavy baryonic matter by the Universe:
$$P_u = \frac{\Omega_h}{\Omega_b} = 0.0065 = 0.65 \; \%$$
$$\boxed{P_u = 0.65 \; \%}$$
Reference:
Cosmological Composition - Pie_Chart - Wikipedia
λCDM model parameters - Wikipedia
14. Jun 26, 2012
### Impaler
On a related note what is the current Rate of burn in the local-galactic-group environment? I've read recently that high red-shift galaxies have been observed that have metal content close to that of present galaxies. This has been interpreted as indicating that the rate of burn was very very high just beyond our limit of observation and that it then slowed down and stayed slow for most of the rest of the universes history.
I'm wondering what kind of time-line we would get if we looked at only the burn-rate extrapolated from luminosity (something we can do with high confidence) and the changing galactic enrichment (also high confidence). Dose it jive?
PS: Orion, dose your heavy Baryon mass fraction include the content still inside of stars, or is it just what's been released into dust/planets etc? At any one time the next batch of heavy Baryons are hidden from view inside Stars but we should be able to estimate this fairly accurately, it might not be inconsequential.
Last edited: Jun 26, 2012
15. Jun 27, 2012
### Orion1
Affirmative, the stellar heavy baryonic matter mass fraction inside stars is included and determined by the emission spectrum and metallicity of stars. It may be more meaningful to simply calculate the lifetime of the Universe, which includes the totality of all the different events occurring inside the Universe up to the present time and beyond.
$H_0 = 2.3298 \cdot 10^{- 18} \; \text{s}^{- 1}$ - Hubble parameter (WMAP)
$\Omega_h = 0.0003$ - λCDM heavy baryonic matter mass fraction
$\Omega_b = 0.0456$ - λCDM baryonic matter mass fraction
Universe heavy baryonic matter stellar burn rate integration by substitution:
$$R_b = \frac{d \Omega}{dt} = \Omega_h H_0 = 6.989 \cdot 10^{-22} \; \frac{d \Omega}{\text{s}}$$
Universe heavy baryonic matter stellar burn rate:
$$\boxed{R_b = 6.989 \cdot 10^{-22} \; \frac{d \Omega}{\text{s}}}$$
Universe baryonic matter stellar epoch burn lifetime integration by substitution:
$$T_s = d \Omega \cdot dt = \frac{\Omega_b}{R_b} = \frac{\Omega_b}{\Omega_h H_0} = 6.524 \cdot 10^{19} \; \text{s} = 2.067 \cdot 10^{12} \; \text{y}$$
Universe baryonic matter stellar epoch burn lifetime:
$$\boxed{T_s = \frac{\Omega_b}{\Omega_h H_0}}$$
Universe baryonic matter stellar epoch burn lifetime:
$$\boxed{T_s = 2.067 \cdot 10^{12} \; \text{y}}$$
Universe age:
$$T_u = \frac{1}{H_0} = 4.292 \cdot 10^{17} \; \text{s} = 1.36 \cdot 10^{10} \; \text{y}$$
$$\boxed{T_u = 1.36 \cdot 10^{10} \; \text{y}}$$
Number of present Universe ages required to complete baryonic matter stellar epoch burn lifetime:
$$n_a = \frac{T_s}{T_u} = \frac{\Omega_b}{\Omega_h} = 152$$
The Universe will be producing stars for a very long time...
Reference:
Universe - Wikipedia
Cosmological Composition - Pie_Chart - Wikipedia
λCDM model parameters - Wikipedia
Heat death of the Universe - Wikipedia
Last edited: Jun 27, 2012
16. Jun 27, 2012
### Impaler
No I was asking what the burn rate is derived from observation of present local space (z = 0), not form extrapolation of theorized age. As I said the burn rate is believed to be changing over time quite substantially, simply dividing the total burn by the total time would almost certainly over-estimate the present rate.
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Physics , 2015, Abstract: We present a purely algebraic formulation (i.e. polynomial equations only) of the minimum-cost multi-impulse orbit transfer problem without time constraints, while keeping all the variables with a precise physical meaning. We apply general algebraic techniques to solve these equations (resultants, Gr\"obner bases, etc.) in several situations of practical interest of different degrees of generality. For instance, we provide a proof of the optimality of the Hohmann transfer for the minimum fuel 2-impulse circular to circular orbit transfer problem, and we provide a general formula for the optimal 2-impulse in-plane transfer between two rotated elliptical orbits under a mild symmetry assumption on the two points where the impulses are applied (which we conjecture that can be removed).
Physics , 2015, DOI: 10.1007/s10509-015-2463-8 Abstract: We study a more complex case of Hohmann orbital transfer of a satellite by considering non-coplanar and elliptical orbits, instead of planar and circular orbits. We use as parameter the angle between the initial and transference planes that minimizes the energy, and therefore the fuel of a satellite, through the application of two non-tangential impulses for all possible cases. We found an analytical expression that minimizes the energy for each configuration. Some reasonable physical constraints are used: we apply impulses at perigee or apogee of the orbit, we consider the duration of the impulse to be short compared to the duration of the trip, we take the nodal line of three orbits to be coincident and the three semimajor axes to lie in the same plane. We study the only four possible cases but assuming non-coplanar elliptic orbits. In addition, we validate our method through a numerical solution obtained by using some of the actual orbital elements of Sputnik I and Vanguard I satellites. For these orbits, we found that the most fuel-efficient transfer is obtained by applying the initial impulse at apocenter and keeping the transfer orbit aligned with the initial orbit.
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.53023 Abstract: Basic resources for communication satellites are communication radio-frequencies and satellite orbits. An orbit is the trajectory followed by the satellite. The communication between the satellite and a ground station is established only when the satellite is consolidated in its own orbit and it is visible from the ground station. Different types of orbits are possible, each suitable for a specific application or mission. Most used orbits are circular, categorized as low, medium and geosynchronous (geostationary) orbits based on the attitude above the Earths surface. The launching process heading the satellite in geostationary orbit, by the first step places the satellite in a transfer orbit. The transfer orbit is elliptical in shape with low attitude at perigee, and the apogee of the geostationary orbit attitude. The apogee of the parking orbit depends on the injection velocity applied at perigee. Simulation approach of injection velocity at perigee to attain different apogees, considering an incremental step is presented in this paper.
Physics , 2015, Abstract: The regular or chaotic character of orbits of stars moving in the meridional plane (R,z) of an axially symmetric elliptical galaxy with a dense, massive spherical nucleus and a dark matter halo component is under investigation. In particular, we explore how the flattening of an elliptical galaxy influences the overall orbital structure of the system, by computing in each case the percentage of chaotic orbits, as well as the percentages of orbits composing the main regular families. In an attempt to discriminate safely and with certainty between regular and chaotic motion, we use the Smaller ALingment Index (SALI) method to extensive samples of orbits obtained by integrating numerically the basic equations of motion as well as the variational equations. In addition, a technique which is based mainly on the field of spectral dynamics that utilizes the Fourier transform of the time series of each coordinate is used for classifying the regular orbits into different families and also to recognize the secondary resonances that usually bifurcate from them. Three cases are considered in our work: (i) the case where the elliptical galaxy is prolate (ii) the case where a spherically symmetric elliptical galaxy is present and (iii) the case where the elliptical galaxy has an oblate shape. Comparison between the current results and early related work is also made.
Physics , 2005, DOI: 10.1088/1464-4266/7/10/011 Abstract: As is well known, when an SU(2) operation acts on a two-level system, its Bloch vector rotates without change of magnitude. Considering a system composed of two two-level systems, it is proven that for a class of nonlocal interactions of the two subsystems including \sigma_i\otimes\sigma_j (with i,j \in {x,y,z}) and the Heisenberg interaction, the geometric description of the motion is particularly simple: each of the two Bloch vectors follows an elliptical orbit within the Bloch sphere. The utility of this result is demonstrated in two applications, the first of which bears on quantum control via quantum interfaces. By employing nonunitary control operations, we extend the idea of controllability to a set of points which are not necessarily connected by unitary transformations. The second application shows how the orbit of the coherence vector can be used to assess the entangling power of Heisenberg exchange interaction.
Riccardo Scarpa Physics , 2003, Abstract: It is shown that the MOdified Newtonian Dynamics (MOND) explains the tilt of the fundamental plane of elliptical galaxies without the need of non-baryonic dark matter. Results found for elliptical galaxies extends to globular clusters and galaxy clusters, showing that MOND agrees with observations over 7 order of magnitude in acceleration.
Alister W. Graham Physics , 2002, DOI: 10.1046/j.1365-8711.2002.05548.x Abstract: The Sersic r^(1/n) index n of an elliptical galaxy (or bulge) has recently been shown to correlate strongly (r=0.8) with a galaxy's central velocity dispersion. This index could therefore prove extremely useful and cost-effective (in terms of both telescope time and data reduction) for many fields of extragalactic research. It is a purely photometric quantity which apparently not only traces the mass of a bulge but has additionally been shown to reflect the degree of bulge concentration. This paper explores the affect of replacing the central velocity dispersion term in the Fundamental Plane with the Sersic index n. Using a sample of early-type galaxies from the Virgo and Fornax clusters, various (B-band) `Photometric Planes' were constructed and found to have a scatter of 0.14-0.17 dex in log(r_e), or a distance error of 38-48% per galaxy (the higher values arising from the inclusion of the S0 galaxies). The corresponding Fundamental Plane yielded a 33-37% error in distance for the same galaxy (sub-)samples (i.e. ~15-30% less scatter). The gains in using a hyperplane (i.e. adding the Sersic index to the Fundamental Plane as a fourth parameter) were small, giving a 27-33% error in distance, depending on the galaxy sample used. The Photometric Plane has been used here to estimate the Virgo-Fornax distance modulus; giving a value of \Delta\mu=0.62(+/-0.30) mag (cf. 0.51(+/-0.21), HST Key Project on the Extragalactic distance Scale). The prospects for using the Photometric Plane at higher redshift appears promising. Using published data on the intermediate redshift cluster Cl 1358+62 (z=0.33) gave a Photometric Plane distance error of 35-41% per galaxy.
Martin D. Weinberg Physics , 1996, DOI: 10.1086/303828 Abstract: Evolution and disruption of galaxies orbiting in the gravitational field of a larger cluster galaxy are driven by three coupled mechanisms: 1) the heating due to its time dependent motion in the primary; 2) mass loss due to the tidal strain field; and 3) orbital decay. Previous work demonstrated that tidal heating is effective well inside the impulse approximation limit. Not only does the overall energy increase over previous predictions, but the work is done deep inside the secondary galaxy, e.g. at or inside the half mass radius in most cases. Here, these ideas applied to cannibalization of elliptical galaxies with fundamental-plane parameters. In summary, satellites which can fall to the center of a cluster giant by dynamical friction are evaporated by internal heating by the time they reach the center. This suggests that true merger-produced multiple nuclei giants should be rare. Specifically, secondaries with mass ratios as small as 1\% on any initial orbit evaporate and those on eccentric orbits with mass ratios as small as 0.1\% evolve significantly and nearly evaporate in a galaxian age. Captured satellites with mass ratios smaller than roughly 1\% have insufficient time to decay to the center. After many accretion events, the model predicts that the merged system has a profile similar to that of the original primary with a weak increase in concentration.
Mathematics , 1992, Abstract: The group PGL(3) of linear transformations of the projective plane acts naturally on the projective space parametrizing curves of a given degree. In this note we begin the study of the orbits of smooth curves under this action: we construct a resolution of the closure of the orbit of a given curve, and we use it to compute its degree. This turns out to depend only on the degree of the curve, the order of its automorphism group, and on the number and type of its flexes. This paper will appear on the Journal of Algebraic Geometry.
Physics , 2001, DOI: 10.1023/A:1024605608482 Abstract: We present a study focusing on the nature of compact groups through the study of their elliptical galaxies. We determine velocity dispersions ($\sigma$) for 18 18 bright elliptical galaxies located in the core of Hickson compact groups and a control sample of 12 bright bona fide ellipticals located in the field or very loose groups. Several tests are carried out to avoid sources of systematic effects in $\sigma$ measurements. We use these velocity dispersions to compare the position of 11 compact group galaxies in the Fundamental Plane to that of a large and homogeneous sample of elliptical galaxies (Burstein et al. 1987). We find that little or no significant difference exists, as far as the Fundamental Plane is concerned, between ellipticals in compact groups and their counterparts in other environments.
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