source_id
int64 1
4.64M
| question
stringlengths 0
28.4k
| response
stringlengths 0
28.8k
| metadata
dict |
|---|---|---|---|
3,784 | At the risk of offending EVERYONE of all political spectrums, should we really accept tweets by Trump as "notable" without explicit evidence that people actually believe them and don't just treat them as hyperbole ? Left-wingers don't believe anything he says on principle. Right wingers explicitly told pollsters or surveyors that they don't necessarily take his statements at face value or factually (they treat them as hyperbole or even symbolic) and would vote for Trump regardless (citation: recent 538 podcast. They are not exactly friends of Trump so hard to claim partisan bias there). So, if most people don't actually believe the claims, merely the fact that he has a wide audience seems to not add up to being notable by the definition Skeptics.SE uses (that people must believe the claim), e.g. we consider humorous or based-on-fictional-stories claims to be off-topic. The question isn't really Trump-specific but Trump does seem like an extreme case where we KNOW he isn't necessarily widely believed despite wide audience. | It is not reasonable to start with the assumption that statements by the 'leader of the free world' are not notable. Every nontrivial thing said by a person with that much power and influence is 'notable' unless proven otherwise. Note that 'notable' does not mean the same thing as 'credible' (and even then we have good evidence that nearly 62 million people take what he says seriously). Even presidents do of course say unimportant things, and this is not to say "I had eggs for breakfast" needs to be fact-checked. Also some presidents make jokes, and we should not take seriously a claim that " Obama is a cartoon lion born in Africa ". But our default assumption should be notability. In terms of the number of people who take Trump's claims seriously - well, we have questions about moon landing hoaxes, and far more people take Trump's claims seriously than that. For those of you as concerned about the current US political situation as I am, there is a good argument to be made that not taking Trump's claims seriously got us where we are today. A lot of news organizations said 'nobody takes what he says seriously', and so didn't spend much effort refuting them. On November 8th 2016 they were proven wrong. I personally know plenty of people who repeat Trump's claims as if they were fact. If you want to consider the "$4b Air Force One" claim as an example, I post 4 sites who took Trump seriously in the comments, and only comment length limits prevented me adding more. The stock market considered his comments notable enough that $1B was wiped off Boeing shares. I'm sorry to have to tell you this, but we are now moving into a reality where everything this man says must be treated seriously. You may not like it, but that's the world we are now in. If our aim is to shine the light of truth on unfounded claims, then there is no reason for us to stop doing it just because it's the President who says it. | {
"source": [
"https://skeptics.meta.stackexchange.com/questions/3784",
"https://skeptics.meta.stackexchange.com",
"https://skeptics.meta.stackexchange.com/users/1044/"
]
} |
3,858 | This is a reminder of an issue that has come up before - around the last US election: Are political comments a problem? If your comment is little more than tribal markings to indicate the US political party you belong to, please don't post it . It will save the effort of another user flagging it, and a bored moderator having to delete it. This is proving to be a problem recently with both pro- and anti-Trump comments. Comments are not intended for you to: signal to others what your politics are. convince others on how to vote. vent about whatever political issue is bugging you. You are welcome to put your political affiliations in your profile if you think anyone cares. You are welcome to have a whin[g]e on Skeptics.SE chat, if you think it will help you feel better. If you can see that an answer has a political bias that disagrees with your own (or even, if you are mature enough, a political bias that agrees with your own), and you are dying to leave a comment about what idiots the other side of politics are - STOP! You can be a lot more help to Skeptics.SE, to your political point of view, and to political discourse in general if you use your special perspective to post another answer, or to make a polite, direct comment about where a mistake or hidden assumption is being made. Who knows? Your answer might get more votes, might get accepted, might help people recognise their blindspots and might convince others that the evidence shows that they are wrong and you are right. Okay, perhaps it is a long-shot for some people, but it has a far better chance than simply staking your ground as a member of a political party and/or which side you think are the bigger dolts. If you see comments that are not constructive in helping explain or solve the question, please continue to flag them - comments on posts can be added without anyone else being informed, so no-one may have noticed before you. | Then do us the same courtesy If you don't care about our political opinions (and you shouldn't; this isn't Politics.SE!), then please ensure that we're not being asked to care about (or silently tolerate) yours. This answer makes a good case in point. A diamond mod has: Taken it upon themselves to completely rewrite the original (and already accepted) answer content, removing large swathes of the OP's text, some of which was critical of Trump; the replacement text is different in tone and generally more supportive of Trump. Edited the neutral header of "Videos showing:" above the links to sources/evidence to the biased/subjective "It does not seem to be an imitation of his disability though", which is not an assertion or interpretation that the answer's OP ever made about the videos and so must be the personal opinion of the moderator. Ignored and deleted multiple comments pointing out that what the videos "seem" to show is actually quite debatable, can be used to support either interpretation, and suggesting that the answer should acknowledge this rather than put forward a subjective interpretation that can't be conclusively supported by the evidence supplied. Made their own comments about how the evidence "is not clear" and thus cannot be used to support "strong statements" either way (as an argument that people stop commenting with their own interpretations of what the evidence seems to show), whilst still not revising their edits to the actual answer to reflect this fact. This at least has the appearance of political bias. And it's more of a problem than us plebes making political comments because it comes from a position of power and authority. Certainly I think there's no question that vague seemings do not count as evidence here, and that it's reasonable to expect our moderators to understand this and to refrain from inserting their opinion about what "seems" to have occurred into other people's answers. And especially into other people's already accepted answers. If you want everyone to keep their political opinions in check, you've got to lead by example. Anything that even appears like political bias coming from an official source should be avoided like the plague. Edit And here's a second example . A diamond mod deleted numerous comments pointing out quality issues with the top-voted answer, and also entire answers (at least two, maybe three?) that provided a more thorough discussion about how the numbers referenced in the OP could be both technically correct and deeply misleading at the same time. No useful purpose is served by suppressing such information, but it does further a particular political viewpoint by omitting relevant context (such as how to do correct statistical analysis and how to not cherry-pick a single datapoint when making broad politically and racially charged assertions). | {
"source": [
"https://skeptics.meta.stackexchange.com/questions/3858",
"https://skeptics.meta.stackexchange.com",
"https://skeptics.meta.stackexchange.com/users/23/"
]
} |
2 | In homeopathic remedies the original substance is often diluted to a point where statistically there should be not a single molecule left of the original substance. The most common explanation by homeopaths, on how it still works although there is no substance left, is that water has a memory . That the "essence" or "imprint" of a molecule can stay in water and continue to have some effect even after the molecule itself is removed. Is this at all possible from a physical point of view? Can water molecules (in the liquid phase) form structures that are stable over long periods of time? | No Water forms strong intermolecular forces between its molecules. This is called hydrogen bonding and is a form of permanent dipole/permanent dipole interaction. Oxygen is more electronegative (its nucleus attracts a bigger share of the electron cloud of the covalent bond) than hydrogen. This causes water to form a permanent dipole where the oxygen has a small negative charge and the hydrogens have small positive charges. File:Hydrogen-bonding-in-water-2D.png This causes electrostatic attraction between water molecules and they can form structures for a small amount of time. Other molecules in the water can affect these short lived structures and water does retain some 'memory' of these molecules. This is how some proponents of homeopathy claim it works. This memory somehow has an opposite effect to the toxin or other chemical that was diluted, although there has not been any mechanism proposed for this. However, the duration of the water memory has been scientifically tested and shown to be very short (less than one billionth of a second). This means that the memory has gone by the time the patient even takes the dose. Even if water did have a long term memory, it would not prove homeopathy. There would also need to be evidence that this water memory had the medical effects that have been claimed. | {
"source": [
"https://skeptics.stackexchange.com/questions/2",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
3 | What is the best evidence available relative to chamomile having relaxing effects? Some examples claims include: It is known for its relaxing and soothing properties It is a mild relaxant and, as such, is often used as an herbal solution to help combat depression, stress and anxiety but is also used for the treatment of other diseases and illnesses. Chamomile has been used for centuries in teas as a mild, relaxing sleep aid | There is a website by the NIH about Chamomile listing the evidence for effectiveness for medicinal purposes. The short summary is, there is insufficient evidence for effectiveness for any of the conditions it is used for. This does not mean that it absolutely does not work, but it means we don't know whether it does anything at all. In absence of any evidence there are two major side effects listed, one is the possibility of miscarriage when taken during pregnancy, the second one are possible allergies. I cannot recommend taking pharmacologically active substances with doubtful efficacy. | {
"source": [
"https://skeptics.stackexchange.com/questions/3",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/31/"
]
} |
12 | Some people blame the preservative thiomersal in vaccines for all kinds of illnesses, but mainly for autism. As thiomersal is a mercury compound, there is some plausibility in suspecting it may cause some damage, but is there some hard data on how dangerous it really is? How comparable are the effects of thiomersal to equal amounts of elementary mercury or methyl mercury? Is there evidence that the amount that was typically used in vaccines (it is seldom used now) is harmful? | Thiomersal itself is toxic in quantity, degrading to ethylmercury (C 2 H 5 Hg + ). As a vaccine preservative, however, it is harmless. (Global Advisory Committee on Vaccine Safety (2006-07-14): "Thiomersal and vaccines" .) This hasn't stopped anti-vaccine activists claiming that the Hg + atom has nigh-magical powers of autism-causing evil, however, despite no link whatsoever having been found with much research. | {
"source": [
"https://skeptics.stackexchange.com/questions/12",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
18 | The placebo effect plays a crucial role in clinical trials and in our understanding of medicine, but I have always had some difficulty in understanding how exactly it works. Is it a purely psychological effect, that you feel better because of the attention the doctors gave you, or are there other aspects to it? Does the placebo effect just change your perception of your condition, so you subjectively feel better although nothing changed about your condition, or does it have real, measurable physical effects? | Some very interesting results along those lines were produced by an asthma study done in 2011: Active Albuterol or Placebo, Sham Acupuncture, or No Intervention in Asthma In a double-blind, crossover pilot study, we randomly assigned 46
patients with asthma to active treatment with an albuterol inhaler, a
placebo inhaler, sham acupuncture, or no intervention . Using a block
design, we administered one each of these four interventions in random
order during four sequential visits (3 to 7 days apart); this
procedure was repeated in two more blocks of visits (for a total of 12
visits by each patient). At each visit, spirometry was performed
repeatedly over a period of 2 hours. Maximum forced expiratory volume
in 1 second (FEV1) was measured, and patients' self-reported
improvement ratings were recorded. (emphasis mine) So after treatment, each patient was given a spirometry test to determine if there was any objective improvement in their lung capactity. They were also asked to report their subjective impression of whether the treatment helped their asthma symptoms. Here are the spirometry test results: The active albuterol treatment group was the only one that showed significant improvement in actual lung capacity after treatment, the placebo and sham acupuncture groups performed the same as those who got no treatment at all. Ah, but what about the patient's subjective impression? All treatment groups felt like their asthma symptoms had significantly improved even though the spirometry test showed no such improvement! So while placebo treatments might make patients feel better about their symptoms, this study suggests that the placebo effect causes no actual objective improvement , and is, therefore, purely psychological. (I can imagine scenarios where this could lead to real harm, like a patient leaving their inhaler at home because they believed they were in better shape than they actually were.) | {
"source": [
"https://skeptics.stackexchange.com/questions/18",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
22 | The use of the " ECA Stack " - ephedrine, caffeine and aspirin - has been common-place in body-building and weight-loss circles. (e.g. in 1999, 2% of the Danish population and 12 million US inhabitants were using some variant. [ Ref ] It is purported to hasten the reduction of body fat and increase athletic performance. After doing some research I can't even find a consistent claim for how this could work. I can see that ephedrine could could reduce body fat (because ephedrine behaves similarly to amphetamines in this regard), but I cannot see how it could increase athletic performance. Is there any science behind this claim? Are there any suggestions about the mechanism? | Some very interesting results along those lines were produced by an asthma study done in 2011: Active Albuterol or Placebo, Sham Acupuncture, or No Intervention in Asthma In a double-blind, crossover pilot study, we randomly assigned 46
patients with asthma to active treatment with an albuterol inhaler, a
placebo inhaler, sham acupuncture, or no intervention . Using a block
design, we administered one each of these four interventions in random
order during four sequential visits (3 to 7 days apart); this
procedure was repeated in two more blocks of visits (for a total of 12
visits by each patient). At each visit, spirometry was performed
repeatedly over a period of 2 hours. Maximum forced expiratory volume
in 1 second (FEV1) was measured, and patients' self-reported
improvement ratings were recorded. (emphasis mine) So after treatment, each patient was given a spirometry test to determine if there was any objective improvement in their lung capactity. They were also asked to report their subjective impression of whether the treatment helped their asthma symptoms. Here are the spirometry test results: The active albuterol treatment group was the only one that showed significant improvement in actual lung capacity after treatment, the placebo and sham acupuncture groups performed the same as those who got no treatment at all. Ah, but what about the patient's subjective impression? All treatment groups felt like their asthma symptoms had significantly improved even though the spirometry test showed no such improvement! So while placebo treatments might make patients feel better about their symptoms, this study suggests that the placebo effect causes no actual objective improvement , and is, therefore, purely psychological. (I can imagine scenarios where this could lead to real harm, like a patient leaving their inhaler at home because they believed they were in better shape than they actually were.) | {
"source": [
"https://skeptics.stackexchange.com/questions/22",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/15/"
]
} |
32 | From a young age, most people are told that vegetables are really good for you and you must eat them... But why? If I eat loads of vegetables for a week, and then the next week I eat nothing but burgers and fries I don't feel in the slightest bit different. Different people have different tastes, but in my opinion, vegetables generally don't taste as good as a burger. Why have my taste buds evolved to like something that is bad for me and dislike something that's good for me. It doesn't make sense. | From a young age, most people are told that vegetables are really good for you and you must eat them Most vegetables are very good for your health - they are high in fiber an d contain essential vitamins and minerals. Also, most vegetables are low calorie and all are cholesterol-free. The Harvard School of Public Heath notes that: "Most people should aim for at least nine servings (at least 4½ cups) of vegetables and fruits a day," and that a diet rich in fruit and vegetables provides the following benefits: Lower blood pressure Reduced risk of heart disease, stroke, and probably some cancers Lower risk of eye and digestive problems A mellowing effect on blood sugar that can help keep appetite in check The United States Department of Agriculture lists the following benefits from a diet rich in fruits and vegetables: Dietary fiber helps reduce blood cholesterol levels and may lower risk of heart disease and is important for proper bowel function. Vegetables are important sources of many nutrients, including potassium, dietary fiber, folate (folic acid), vitamin A, vitamin E, and vitamin C. Eating vegetables rich in potassium may reduce the risk of developing kidney stones and may help to decrease bone loss. In my opinion, vegetables generally don't taste as good as a burger. Why so why have my taste buds evolved to like something that is bad for me and dislike something that's good for me. It doesn't make sense. Our taste buds have evolved to identify high calorie items as tasty - sugar, fats, and protein. These types of food provide a much higher ratio of calories per gram. For much of our evolutionary history, given a choice between a fatty slab of meat and broccoli, those ancestors that chose the steak would have gained more calories and thereby increased their odds of not starving to death. Consequently, these genes got passed down the evolutionary tree. Eating unhealthily is not the only example of things that feel good, but are bad for you. Take exercise. In our prehistoric past, a human who exerted less energy would have a greater chance at survival as he'd require less calories per day. A caveman would not needlessly run a half marathon for exercise or sport; rather, he'd conserve his energy with a more lax task - tool making or story telling. As a result, it "feels better" to sit down in front of the computer or TV than it does to go to the gym, but we know that such a sedentary lifestyle is not healthy, especially given our high-calorie and unhealthy diets. | {
"source": [
"https://skeptics.stackexchange.com/questions/32",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/40/"
]
} |
41 | There is lots of evidence that I have seen showing correlation between human activities and climate change but what evidence is there to support causation ? | Humans affect the weather in mainly the following ways: Direct emissions of various gasses Typically CO 2 is considered, but also other greenhouse gasses. The greenhouse effect of carbon dioxide was first measured in 1859. source In the 19th century, scientists realized that gases in the atmosphere cause a "greenhouse effect" which affects the planet's temperature. These scientists were interested chiefly in the possibility that a lower level of carbon dioxide gas might explain the ice ages of the distant past. At the turn of the century, Svante Arrhenius calculated that emissions from human industry might someday bring a global warming. Other scientists dismissed his idea as faulty. In 1938, G.S. Callendar argued that the level of carbon dioxide was climbing and raising global temperature, but most scientists found his arguments implausible. It was almost by chance that a few researchers in the 1950s discovered that global warming truly was possible. In the early 1960s, C.D. Keeling measured the level of carbon dioxide in the atmosphere: it was rising fast. Researchers began to take an interest, struggling to understand how the level of carbon dioxide had changed in the past, and how the level was influenced by chemical and biological forces. They found that the gas plays a crucial role in climate change, so that the rising level could gravely affect our future. — The Carbon Dioxide Greenhouse Effect source Farming Another man-made source is the direct emission of greenhouse gasses through farming (funny, but true!): manure (and cows) produce methane which is a pretty effective greenhouse gas. source Increasing atmospheric concentrations of methane have led scientists to examine its sources of origin. Ruminant livestock can produce 250 to 500 L of methane per day. This level of production results in estimates of the contribution by cattle to global warming that may occur in the next 50 to 100 yr to be a little less than 2%. — Methane emissions from cattle Deforestation Plants "fix" carbon (a phenomena called "Carbon sequestration"), the less plants, the less fixing (and the more carbon released by fires). source — Carbon sequestration: Forest and soil, by Jukka Muukkonen, Statistics Finland The Oceans Changes to the biological equilibrium of the oceans affect the climate because marine biology is known to have a large carbon-fixating effect source One of the most promising places to sequester carbon is in the oceans, which currently take up a third of the carbon emitted by human activity, roughly two billion metric tons each year. — Carbon Sequestration in the Ocean Conclusion All four of these effect can be shown in a laboratory and no model is required to do so, but we have very very good models to explain the lab experiments. Differently from the lab, the whole climate system is much less understood. And, yes, the model are not as reliable as we would like. However — due to our knowledge of chemistry — it is undeniable that we are affecting climate. Note that nobody has asserted that human intervention is the only cause of climate change, but it can be said, with a straight face, that humans are changing climate.
A very simple example, the rise in temperature melts ice at the pole - which is not only responsible for reflecting some light out of the atmosphere, but also contains methane, which is then released. The debate can only be on "how much" and "how well can we reverse the trend (even beyond our contribution)". | {
"source": [
"https://skeptics.stackexchange.com/questions/41",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/25/"
]
} |
57 | I listened to episode 140 of the The Psych Files podcast where the host, Michael Britt, tried to psychoanalyze Jack Lalanne and was left wondering whether there's any validity to it. I am under the impression that psychoanalysis is a pseudoscience and is not used by psychologists anymore. Is there any scientific validity to psychoanalysis? Or was the podcast host just having fun with it? | Psychoanalysis isn't used in the form that Sigmund Freud once designed by educated psychologists. Many present-day psychotherapists still use techniques that bear Freud's imprint, but they have modified the treatment in various ways. The intensity of Freud
's design has been diminished, Freud insisted on at least three sessions of psychotherapy according to his own psychoanalysis. Also, the typical couch on which patients could relax while the psychologist sat outside of the patients' view is no longer used. Modern Neo-Freudian practitioners more commonly known as psychodynamic, ego-analytic and object-relations therapists, emphasize current interpersonal and cultural factors, where classical psychoanalysis emphasizes on past factors mainly. Another change in modern psychoanalysis-based therapies is that patients are encouraged to apply what they have learned in their sessions with a therapist, whereas classical psychoanalysis therapy was thought to only be effective if no major life changes were made. (Like getting married, divorced, having children, etc.) So the patients life should be stable during the psychoanalysis therapy. Although psychoanalysis has been the foundation of many therapies that have been scientifically proven to work, it's original form is no longer used in modern day psychological treatments. So, concluding, as stated by Scott Mitchell's comment: Yes, classical Freudian psychoanalysis is pseudoscience, but modern psychoanalytical techniques are evidence-based. Here's a paper published in American Psychologist that presents research that "supports the efficacy and effectiveness of psychodynamic therapy"
- apsa.org/portals/1/docs/news/JonathanShedlerStudy20100202.pdf | {
"source": [
"https://skeptics.stackexchange.com/questions/57",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/59/"
]
} |
59 | I've heard claims that the average person uses only 10% of their "brain power," whatever that means. The implication, though, is that there the majority of our brain's potential is untapped. However, I've often heard this refrain from people who are selling "training" or "secrets" to unlock the unused potential of our brain. It seems unlikely that there would be evolutionary advantages to having a brain whose capabilities lie largely untapped. I'm curious - what percentage of our brain do we use, or can it even be quantified in such measures? | No. I believe snopes.com has some solid information on this topic: The Ten-Percent Myth . There is also the 10% of brain myth article on Wikipedia: Neurologist Barry Gordon describes the myth as laughably false, adding, "we use virtually every part of the brain, and that [most of] the brain is active almost all the time". Neuroscientist Barry Beyerstein sets out seven kinds of evidence refuting the ten percent myth: Studies of brain damage: If 90% of the brain is normally unused, then damage to these areas should not impair performance. Instead, there is almost no area of the brain that can be damaged without loss of abilities. Even slight damage to small areas of the brain can have profound effects. Evolution: The brain is enormously costly to the rest of the body, in terms of oxygen and nutrient consumption. It can require up to twenty percent of the body's energy — more than any other organ — despite making up only 2% of the human body by weight.[6][7] If 90% of it were unnecessary, there would be a large survival advantage to humans with smaller, more efficient brains. If this were true, the process of natural selection would have eliminated the inefficient brains. By the same token, it is also highly unlikely that a brain with so much redundant matter would have evolved in the first place. Brain imaging: Technologies such as Positron Emission Tomography (PET) and functional magnetic resonance imaging (fMRI) allow the activity of the living brain to be monitored. They reveal that even during sleep, all parts of the brain show some level of "activity. Only in the case of serious damage does a brain have "silent" areas. Localization of function: Rather than acting as a single mass, the brain has distinct regions for different kinds of information processing. Decades of research has gone into mapping functions onto areas of the brain, and no function-less areas have been found. Microstructural analysis: In the single-unit recording technique, researchers insert a tiny electrode into the brain to monitor the activity of a single cell. If 90% of cells were unused, then this technique would have revealed that. Metabolic studies: Another scientific technique involves studying the take-up of radioactively labelled 2-deoxyglucose molecules by the brain. If 90 percent of the brain were inactive, then those inactive cells would show up as blank areas in a radiograph of the brain. Again, there is no such result. Neural disease: Brain cells that are not used have a tendency to degenerate. Hence if 90% of the brain were inactive, autopsy of adult brains would reveal large-scale degeneration. Here is an article from Scientific American: Do we really use only 10 percent of our brains? and a Google search turns up many, many more article which all say the same thing. I couldn't find anything which argued otherwise. | {
"source": [
"https://skeptics.stackexchange.com/questions/59",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/64/"
]
} |
74 | Over the years, Neuro Linguistic Programming (NLP) has been creeping into popular culture. It is used by a lot of self-help gurus, and also in context of the right way to educate and learn ( e.g. , visual learner, auditory learner, etc.) At its core the NLP presuppositions seem vague. ( e.g. , "Choice is better than no choice", "People work perfectly", "All actions have a purpose.") My question is: Is there any credible proof of NLP being anything more than just placebo? (In my mind I was comparing The Seven Hermetic Principles [not that I subscribe to them] and NLP — trying to to figure out if NLP can score more points than the 7 principles in being scientific, verifiable and substantial.) | It seems that there is no scientific basis for NLP. Reading this article from 2009 From the abstract: It concludes that after three
decades, there is still no credible
theoretical basis for NLP, researchers
having failed to establish any
evidence for its efficacy that is not
anecdotal. And from the conclusion: (link not in original quote) To adapt this [Cargo Cult] term one more time, NLP
masquerades as a legitimate form of
psychotherapy, makes unsubstantiated
claims about how humans think and
behave, purports to encourage research
in a vain attempt to gain credibility,
yet fails to provide evidence that it
actually works. Neuro-linguistic
programming is cargo cult psychology. | {
"source": [
"https://skeptics.stackexchange.com/questions/74",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/81/"
]
} |
88 | "Everyone knows" - a scary statement - that you get "a cold" from being cold. Now it seems to be a fact that you don't, because you get a cold from a (rhino)virus, not from the temperature. But is there any correlation between temperature and disease ? I've seen claims that "cold lowers your immune system", and stuff like that, but no real evidence. As soon as you look into scientific research about this, you get claims that the correlation is not causation, because in the winter people spend more time inside (close to one another) for instance. (See for instance this article ) On the other hand - and I know this is a really bad form of reasoning -- I think if I'd go outside in the freezing cold wearing nothing but some summer pants, I'd not come out of that after a couple of hours like a happy camper. Is this non-sense, or is there some correlation between being cold (or even undercooled?) and disease? If so, how does this work? | Aside from the effect of cold temperatures on the human body, it's also important to consider the effect of cold temperatures on the virus . One study found reduced virus infectivity at 37 degrees celcius while it was stable at 6 and 23 degrees. And while we're at it, there's even more data on the flu. Quite a few studies found that "cold temperatures and low relative humidity are favorable to the spread of influenza virus." So humidity is also important, as well as the interaction between humidity and temperature : there seems to be some general indication that minimal survival for both lipid-enveloped [e.g. influenza] and non-lipid-enveloped viruses [e.g. rhinoviruses] occurs at an intermediate RH [relative humidity] of 40–70% (Arundel et al. 1986). Also, it is important to note that temperature and RH will always interact to affect the survival of airborne viruses in aerosols. [Edit: In my initial answer I suggested that being cold doesn't make a difference to you. That's not quite true. It does seem to increase susceptibility to infection , though of course the point is that you do need to be exposed to a virus; you don't get a cold just from being cold.] While temperature may have an effect on your susceptibility to infection, it also has an effect on the survival of the virus outside your body. They prefer colder (less humid) environments. This does mean you're more likely to catch a cold when it's cold, because the virus is more likely to survive and be transmitted. | {
"source": [
"https://skeptics.stackexchange.com/questions/88",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/83/"
]
} |
95 | I was sent the following link by a friend and they were concerned that someone was passing it around on Twitter. What would be some good refutations for its content? Infowars: Vaccine Deaths And Injuries Skyrocket As Cover-up Implodes "Cases of debilitating illnesses, soft-kill side-effects and even
instant deaths as a result of
vaccinations across the world are
skyrocketing as the cover-up of deadly
inoculations implodes and more people
than ever become suspicious about what
they are being injected with by health
authorities who have proven they
cannot be trusted. The implosion of
the vaccine cover-up is sure to
discourage more parents from
vaccinating their children in the
coming months, with the swine flu shot
now being combined with the regular
seasonal flu jab. A recent Rasmussen
poll found that 52 per cent of
Americans were concerned about the
safety of vaccines as we approach the
start of school and college terms,
where many children and teenagers will
be “required” to take shots before
they can attend..." | Well, the facts are that the process of vaccination involves injecting you with an antigen very similar to the thing you are to gain immunization to, so that your immune system may familiarize with it in a controlled environment. Ideally, this similar antigen should be harmless, but so similar that your immunity towards the injected antigen will transfer to immunity to the actual disease. It is known that this is not entirely without side effects. It is indeed possible that you become ill from the very antigen you're injecting. This is not at all what the anti vax people are stressing up about, however. Probably because it's well documented that there's a significantly greater risk in not getting vaccinated. Now, the article you're referencing is problematic because it bundles together several completely different issues. For one part, it deals with the case of the H1N1 vaccine and the alleged links to narcolepsy which is an actual scientific debate regarding a brand new vaccine, and the claims are currently being investigated rigorously. There's one report going on in Finland from which we've only seen preliminary results (!) which seem to vindicate the connection, and there's another study in Sweden hopefully to be published within a few months. Until those studies are published, I wouldn't dare comment on the likelihood of a connection. If you're in the H1N1 high risk demography, at least Swedish government still recommends the vaccine. For these guys, this just confirms their assumption that all vaccines are dangerious and should be avoided . But the H1N1 story says nothing that will validate the links between the MMR vaccine and autism, for instance. This is an entirely different claim, it is about a vaccine that's been in long use, and it's been refuted countless times . The alleged autism claim is based solely on an Andrew Wakefield study that's been shown since long to be a complete scam . So there's no simple answer to the vaccine story, because it's not one story. These guys are cross-pollinating the news in a manner that doesn't make sense, to try and validate a long debunked theory. What can be said is that all of this is very tragic. The vaccine scare has given us an increase in pertussis morbidity, which is a disease we can avoid entirely . I know this'll come off as an argument from emotion here, but I really think it's a shame that people are still dying from pertussis, due to ignorance and fear mongering alone, when we have the very simple means to defeat it. | {
"source": [
"https://skeptics.stackexchange.com/questions/95",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/4/"
]
} |
100 | How much Homeopathic medicines would be required (or considered) an overdose? Every Homeopathic site claims the treatments are safe and have no side effects, it it even possible to overdose? | Yes, it is entirely possible to overdose on almost anything. liquid (water) homepathic medicine can of course cause water intoxication sugar pills can cause problems with blood sugar I presume, although I do not know in what amounts. liquid (alcohol) we all know this one :) | {
"source": [
"https://skeptics.stackexchange.com/questions/100",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/4/"
]
} |
101 | According to Darwin, the absence of intermediate fossil forms “is the most obvious and gravest objection which can be urged against my theory.” What new fossil finds, if any, have occurred since Darwin wrote these words nearly 150 years ago? Do they overturn Darwin’s bleak assessment of evolutionary theory? If the absence of intermediate fossil forms holds as much today as it did back then, why should anyone accept evolution? This question is taken from Five
Questions Evolutionists Would Rather
Dodge By William A. Dembski , I
have asked it here so the rationalist,
scientific and skeptical communities
can collectively provide well
researched and logically sound
answers. | The absence doesn't hold up. In fact there are tons of intermediate fossils . Good examples are the evolution of birds and humans. Early birds are more or less just dinosaurs with wings (and we now know that many dinosaurs had primitive feathers as well ). And with this you can see a clear path from dinosaurs, to bird-like dinosaurs with feathers, to early dinosaur-like birds to birds, so therefore the bird-like dinosaurs and dinosaur-like birds are in fact intermediate fossil forms between dinosaurs and birds. In human evolution we can clearly see that australopithecines, being upright-walking apes , are intermediate between apes and humans, and that early homo in turn is intermediate between australopithecines and homo sapiens. The argument is then sometimes said that they are not intermediate forms between species . But that argument doesn't hold up because the line between species isn't necessarily sharp. It's an arbitrary grouping we humans do. You can't have an intermediate form between two species, because we will decide which species it belongs to. But nature makes no such distinctions. Normally the animals within one species can interbreed, but no interbreeding can be done between species. But there are species of birds where birds from the eastern part of the population will not mate with birds from the western part of the population. But yet there is never a clean break in between. And everyone knows Coyotes and Gray Wolves are different species, right? But Gray Wolves can (and sometimes do) mate with red wolves, that can (and sometimes do) mate with Coyotes.
(In fact there is some speculation that the Red Wolf itself is a mix between Gray Wolf and Coyote . I don't know if any conclusion has been drawn on that). In evolution it is even more self-evident that there is no clean break between species, and one species slowly evolves from another. So if you find an intermediary form, i.e. something you can't clearly specify as species A or species B, you tend to give it a species of it's own (with a significant expansion of species in Homo during the last decades as a result). So the grouping of individuals into species are often arbitrary, and as long as we always stick every individual into one species, we won't get intermediary forms between species. But it's clear that different species are intermediary forms of other species, so the evidence is there in the fossil record, with no doubt. | {
"source": [
"https://skeptics.stackexchange.com/questions/101",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/4/"
]
} |
119 | Promoted by Jim Humble , Miracle Mineral Solution is claimed to cure a wide range of ailments. But what exactly is it, chemically speaking? | According to the FDA , the Miracle Mineral Solution produces an industrial bleach: The product, when used as directed, produces an industrial bleach that can cause serious harm to health. The product instructs consumers to mix the 28 percent sodium chlorite solution with an acid such as citrus juice. This mixture produces chlorine dioxide , a potent bleach used for stripping textiles and industrial water treatment. High oral doses of this bleach, such as those recommended in the labeling, can cause nausea, vomiting, diarrhea, and symptoms of severe dehydration. Health Canada issued a similar warning : According to the information provided on the company's website, Miracle Mineral Solution is a 28% solution of sodium chlorite. Health Canada advises that sodium chlorite is a chemical used mainly as a textile bleaching agent and disinfectant. | {
"source": [
"https://skeptics.stackexchange.com/questions/119",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/4/"
]
} |
136 | Do magnets have statistically significant effects on humans? Some example claims are in the Wikipedia article on Magnet therapy . Which says: Practitioners claim that subjecting certain parts of the body to
magnetostatic fields produced by permanent magnets has beneficial
health effects. These claims are both physically and biologically
implausible and no effects on health or healing have been established. | While there are studies that have shown some relief of pain, most do not show those results . Given the other factors that could cause false-positives, it seems unlikely that the magnets are the cause. What the Science Says About Magnets for Pain Scientific evidence does not support the use of magnets for pain relief. Preliminary studies looking at different types of pain—such as knee, hip, wrist, foot, back, and pelvic pain—have had mixed results. Some of these studies, including a 2007 clinical trial sponsored by the National Institutes of Health that looked at back pain in a small group of people, have suggested a benefit from using magnets. However, many studies have not been of high quality; they included a small number of participants, were too short, and/or were inadequately controlled. The majority of rigorous trials, however, have found no effect on pain. | {
"source": [
"https://skeptics.stackexchange.com/questions/136",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/116/"
]
} |
138 | The Bates Method is often cited by people looking to avoid wearing glasses, or as an alternative to LAZIK surgery for improving/correcting eyesight. Is the method at all effective? Can eyesight truly be improved/repaired through exercise and lifestyle changes? | Unsurprisingly, it does not work. As any other "alternative" medicine, it should be treated with the utmost caution, the general principle being "alternative medicine that works is called medicine." The findings of Visual Training for Refractive Errors CTA - October 2004 , a meta-analysis from the American Academy of Ophthalmology , are summarised below by Wikipedia (emphasis mine): No evidence was found that [visual training] techniques could objectively benefit eyesight , though some studies noted changes, both positive and negative, in the visual acuity of nearsighted subjects as measured by a Snellen chart. In some cases noted improvements were maintained at subsequent follow-ups. However, these results were not seen as actual reversals of nearsightedness, and were attributed instead to factors such as "improvements in interpreting blurred images, changes in mood or motivation, creation of an artificial contact lens by tear film changes, or a pinhole effect from miosis of the pupil." Wikipedia goes on to quote a second report : In 2005 the Ophthalmology Department
of New Zealand's Christchurch Hospital
published a review of forty-three
studies regarding the use of eye
exercises. They found that "As yet there is no clear scientific evidence
published in the mainstream literature
supporting the use of eye exercises "
to improve visual acuity, and
concluded that "their use therefore
remains controversial." | {
"source": [
"https://skeptics.stackexchange.com/questions/138",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/116/"
]
} |
150 | The China Study authors state that: osteoporosis is linked to the consumption of animal protein because animal protein, unlike plant protein, increases the acidity of blood and tissues. They add that to neutralize this acid, calcium (a very effective base) is pulled from the bones, which weakens them and puts them at greater risk for fracture." from Wikipedia As noted, they found "in [their] rural China Study, where the animal to plant ratio [consumption of protein] was about 10 percent, the fracture rate is only one-fifth that of the U.S. (p. 205, 208)" Does that mean that drinking milk actually can lead to osteoporosis, rather than prevent it? | Lanham-New et al. 1 compared the literature for bone health in ovo-lacto-vegetarians and vegan diets against omnivores with predominantly meat diets. They found no difference in bone-health indices between those two groups. This review indicates that the source of the dietary protein does not make a significant difference for bone health. The claim that animal proteins increase the acidity of the blood is also not credible. The pH value of the blood and inside cells is tightly regulated 2 and not easily influenced by diet. The content of the stomach there is already a very acidic environment, which shows that the pH can be effectively regulated by the body. There are also several studies indicating that milk consumption has a positive effect on bone health and decreases the risk of osteoporosis: Effects of calcium intake, milk and dairy product intake, and blood vitamin D level on osteoporosis risk in Korean adults: analysis of the 2008 and 2009 Korea National Health and Nutrition Examination Survey : The results of this study showed that BMD increases as Ca intakes
increases, and that the risk of osteoporosis incidence was reduced
when more than 1 serving of milk or dairy products were consumed and
serum 25(OH) vitamin D level was maintained in the normal range Calcium, dairy products and osteoporosis : Of 52 investigator-controlled calcium intervention studies, all but
two showed better bone balance at high intakes, or greater bone gain
during growth, or reduced bone loss in the elderly, or reduced
fracture risk. [...] While most of the investigator-controlled studies
used calcium supplements, six used dairy sources of calcium; all were
positive. Most of the observational studies were based on dairy
calcium also, since at the time the studies were done, higher calcium
intakes meant higher dairy intakes. [1] S.A. Lanham-Newa, W.T.K. Leea, D.J. Torgersonb and D.J. Millwarda, Is vegetable protein more beneficial to bone than animal protein?, International Congress Series 1297 , Nutritional Aspects of Osteoporosis 2006. Proceedings of the 6th International Symposium on Nutritional Aspects of Osteoporosis (2006) [2] Lodish et al., Molecular Cell Biology. 4th edition, New York: W. H. Freeman (2000). | {
"source": [
"https://skeptics.stackexchange.com/questions/150",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/111/"
]
} |
155 | Many different sources claim to be able to produce "unlimited free energy". For example: UNLIMITED FREE ENERGY IDENTIFIED Company claims to have developed new technology that provides unlimited free energy Is it possible to create energy out of nowhere? | Creating energy out of nowhere violates the first law of thermodynamics . Energy can only be changed from one form to another, e.g. from kinetic energy to heat, but it can neither be created nor destroyed. This is an empirical law, but it has a lot of experimental evidence behind it. It would take some extremely convincing evidence to overthrow it, not to mention a whole lot of new physics. | {
"source": [
"https://skeptics.stackexchange.com/questions/155",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/31/"
]
} |
191 | I often hear the claim that "chemtrails" have to exist, because normal contrails don't linger very long. Is there a definitive scientific explanation for why normal contrails sometimes do, in fact stick around and sometimes even seed very large clouds? An ideal explanation would also clearly state why one wouldn't be able to identify the correct conditions from the ground. | The longevity of a contrail is dependent on the weather conditions which indeed might be difficult to spot from the ground. I don't know about "unable" though. As far as I know the 'controversy' about contrails has never had any substantial evidence. As for the time a contrail is visible, the most described factor is Humidity 1 : When the ambient relative humidity is high, the resulting ice-crystal plume may last for several hours. Here is an article explaining how the trails have been used by sailors for forecasting, and has a couple of links to other articles explaining the phenomenon. (1) Encyclopedia Britannica | {
"source": [
"https://skeptics.stackexchange.com/questions/191",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/67/"
]
} |
195 | The number of diagnosed cases of autism has increased substantially in the last decades as seen in the following graph. Bar chart of the number (per 1,000 U.S. resident children aged 6–17) of children aged 6–17 who were served under the Individuals with Disabilities Education Act (IDEA) with a diagnosis of autism, from 1996 through 2007. Image from Wikimedia Commons How can this increase be explained. Are there environmental factors that contribute to a higher rate of autism today? Or did we just get better at diagnosing autism? | First of all if you look at the original data , things are way more suspicious. Why are they suspicious? Because most mental illnesses are actually also increasing dramatically during that period . One can speak about epidemiology of a single disease, but when there are many diseases with the same trend, producing that graph is clearly cherry-picking the data to show that there must be something wrong with autism in particular! So this leads us clearly to systematic causes, like improved diagnostics, changed diagnostic criteria and age at which the diagnosis can be produced, etcetera. Obviously this doesn't disprove that autism has increased. It might have increased as well, but it's hard to say in a situation in which a proper study hasn't been conducted. Let me quote Wikipedia : More children may have autism; that is, the true frequency of autism may
have increased. There may be more complete pickup of autism (case finding), as a result
of increased awareness and funding.
For example, attempts to sue vaccine
companies may have increased
case-reporting. The diagnosis may be applied more broadly than before, as a result of
the changing definition of the
disorder, particularly changes in
DSM-III-R and DSM-IV. Successively earlier diagnosis in each succeeding cohort of children,
including recognition in nursery
(preschool), may have affected
apparent prevalence but not incidence. A review of the "rising autism" figures compared to other disabilities
in schools shows a corresponding drop
in findings of mental retardation. The article also contains a pretty damning conclusion: The reported increase is largely attributable to changes in diagnostic practices, referral patterns, availability of services, age at diagnosis, and public awareness. The following studies are referenced (emphasis mine): More children are being diagnosed with ASDs today than in the past. Some of the prevalence increase is undoubtedly attributable to changing diagnostic tendency; however, there are insufficient data to determine whether this can explain the entire increasing trend. — source The prevalence of autism in metropolitan Atlanta in 1996 for children aged 3 to 10 was 3.4 per 1000. This overall rate is 10 times higher than rates from 3 other US studies that used DSM-III or ICD-9 criteria to identify children with autism and pervasive developmental disorders in the 1980s and early 1990s. Our rate is closer to that found in a recent prevalence study in Brick Township, New Jersey, that used DSM-IV criteria (4.0 per 1000 for autistic disorder and 6.7 per 1000 for the entire autism spectrum). Our findings also are similar to rates from several recent European studies that used ICD-10 or DSM-IV criteria (2-6 per 1000 for autism). — source | {
"source": [
"https://skeptics.stackexchange.com/questions/195",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
227 | An unusual number of ships and planes are said to have disappeared without a trace in the area called the Bermuda Triangle. This has caused some people to claim supernatural causes for these mysterious disappearances. Are there more ships and planes disappearing in the Bermuda Triangle than in other regions, or is that just an inaccurate perception? If there are more ships and planes lost there, are there natural explanations for that? | According to the US Coast guard , the losses experienced in the triangle are no greater than in any other area of ocean: [the triangle] is noted for an apparent high incidence of unexplained losses of ship, small boats, and aircraft. The Coast Guard does not recognize the
existence of the so-called Bermuda
Triangle as a geographic area of
specific hazard to ships or planes. In
a review of many aircraft and vessel
losses in the area over the years,
there has been nothing discovered that
would indicate that casualties were
the result of anything other than
physical causes. No extraordinary
factors have ever been identified. There are unusual natural factors in the Bermuda Triangle, but they are known and exist similarly in various other locations worldwide ( source ): A significant factor with regard to
missing vessels in the Bermuda
Triangle is a strong ocean current
called the Gulf Stream. It is
extremely swift and turbulent and can
quickly erase evidence of a disaster...the topography of the ocean floor
varies from extensive shoals around
the islands to some of the deepest
marine trenches in the world. With the
interaction of the strong currents
over the many reefs the topography of
the ocean bottom is in a state of flux
and the development of new
navigational hazards can sometimes be
swift. With regards to the perpetuation of the "mystery", Skepdic concludes: In short, the mystery of the Bermuda
Triangle became a mystery by a kind of
communal reinforcement among
uncritical authors and a willing mass
media to uncritically pass on the
speculation that something mysterious
is going on in the Atlantic. | {
"source": [
"https://skeptics.stackexchange.com/questions/227",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
256 | The Mayan calendar completes its 5,125 year cycle, on 21 December 2012. Is there any evidence they foresaw the end-of-the-world? | Contrary to popular opinion, the mayan calendar does not end in 2012, it merely begins a new cycle . “There will be another cycle,” Andrews
says. “We know the Maya thought there
was one before this, and that implies
they were comfortable with the idea of
another one after this.” E. Wyllys Andrews The Mayan calendar is based on cycles, that does not mean they thought the world ended at that specific point the cycle ends. And regardless of what the Mayans thought, there is no evidence for any world-ending event happening in 2012. Update: The world didn't end on 21 December 2012. | {
"source": [
"https://skeptics.stackexchange.com/questions/256",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/4/"
]
} |
286 | According to the web site of the film Vanishing of the Bees : Bees are dying in their billions. In the UK, around one fifth of honeybee hives were lost in the winter of 2008/2009. Is there evidence of bees disappearing and what are scientific theories on this subject? | I would hesitate to say that "bees are disappearing". But yes, there is a problem. It's called Colony Collapse Disorder and there is nothing certain about why it happens. It's probably a combination of factors. The Wikipedia article is good. I've recently read some articles claiming that they have found a definitive link to some disease, but I can't find it right now, so I don't know if there is any good basis for the claim. Update: The claims blaming the pesticide Imidacloprid seems promising and seem to be the strongest claims of a cause at the moment. | {
"source": [
"https://skeptics.stackexchange.com/questions/286",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/123/"
]
} |
289 | Some urban legends and myths revolve around surgery occurring to a person who has had too much to drink. Is it possible to, as a side effect of the patient drinking too much, reach a point where surgery can be performed without the patient regaining consciousness? | I've found a paper about Ethanol as a general anesthetic and in their introduction they state [..] ethanol can produce a state of
general anesthesia and historically
has been used for this purpose (Dundee
et al., 1969). Ethanol causes amnesia
and loss of consiousness in man, and
in experimental animals can cause
immobility in response to a noxious
stimulus. Immobility in response to a
noxious stimulus is the endpoint of
the most common operational definition
of general anesthesia. The article cited inside that quote is "Use of alcohol in anesthesia" which I can't access. It seems ethanol has been used as an anesthetic, although it is probably difficult to administer and most likely very dangerous. Most anesthetics have a very narrow therapeutic range , so the amount needed to kill someone is not that much higher than the amount needed for the drug effect. With ethanol you will have the problem that many people will probably throw up before you can get enough alcohol into them to render them unconscious. | {
"source": [
"https://skeptics.stackexchange.com/questions/289",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/116/"
]
} |
297 | The energy-saving compact fluorecent lamps (CFLs) contain some amount of mercury. If they break, it might be released. I've heard claims that they are really dangerous, and claims that the amount of mercury is completely harmless. So how dangerous are they, do I need to call a Hazmat team when I break one? | According to the WHMIS documents (French only) provided by the Commission de la santé et de la sécurité du travail (CSST), you're under no immediate danger. Here's the relevant passage, translated from French: Exposure to vapors: Mercury has no scent. As such, we can only detect its presence with instruments. At ambient temperature (20°C), mercury possesses a saturation concentration of 1.6 ppm (13 mg/m³), which is 160 times the occupational exposure limit (0,003 ppm or 0,025 mg/m³). As a result, in the event of a leak or spill in a room, a significant quantity of mercury evaporates and the OEL is easily surpassed. However, in practice, the IDLH (1,2 ppm or 10 mg/m³) is never surpassed, even if it is really near of the saturation concentration. Put in simpler terms, at ambient temperature, a concentration which would be dangerous to be exposed to for a long period of time is easily reached. However, the concentration at which your health is immediately threatened is rarely reached. There's no reason to panic or to put on an Hazmat suit. If you break a CFL, just follow the EPA's recommendations on how to clean up a broken CFL : Open the window. Carefully collect the debris. Avoid dermal contact with the broken bulb. Clean the surface thoroughly. Don't keep the debris inside. | {
"source": [
"https://skeptics.stackexchange.com/questions/297",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
299 | Is there any reason for a healthy adult to take a daily multi-vitamin? My intuition tells me that an adult eating a healthy and balanced diet will get all of the nutrients she needs and that taking a daily mulit-vitamin would be pointless. | There answer is not necessarily a simple "yes" or "no." Way too little of a vitamin is a terrible thing, and way too much can be just as bad, although you must reach rather high levels to contract vitamin intoxication. A "what's the harm" attitude towards multivitamins is arguably defensible, as you're not running a risk of vitamin intoxication from following the recommended dosage. It rather boils down to whether or not you're willing to spend the money and go through the daily routine, when it's not at all obvious that you should need to. Vitamin supplements are all about avoiding a vitamin deficiency. There really is no added benefit to getting more vitamins once you're at sufficient levels. The trick is that it's not that easy to keep track of whether or not you are. The rule cannot be generalized into saying "Healthy adults don't need vitamin supplements, because in order to be healthy, you must not have a vitamin deficiency." You're not likely to catch scurvy unless you're doing something terribly wrong. That's not what this is all about. There can be more subtle effects of small vitamin deficiencies. Vitamins can help you fend off other diseases, for instance: Vitamin D from a multivitamin or single supplement can lower the risk of colon and possibly many other cancers. * harvard.edu The process of self-diagnosis should not simply be "Do I suffer from scurvy? No; ergo I'm getting all the vitamin C I need." Rather, you should be asking my self "Am I avoiding colon cancer as best I can?" That question is trickier to answer. No , you do not need vitamin supplements if you get sufficient levels of vitamins anyway. There is no added benefit to getting more than enough vitamins. But I can't generalize that into "eating a healthy and balanced diet", as per your question. First of all, that phrase probably entails different specific details depending on the individual. But, more importantly, I'd like to stress that it's not all about your diet. The richest source of vitamin D, for instance, is exposure to the sun. If you live north of the line connecting San Francisco to Philadelphia and Athens to Beijing, odds are that you don't get enough vitamin D. The same holds true if you don't get outside for at least a 15-minute daily walk in the sun. African-Americans and others with dark skin, as well as older individuals, tend to have much lower levels of vitamin D, as do people who are overweight or obese. * harvard.edu It is worth looking into whether or not you belong to any of the risk groups, to assess whether or not you would be in need of supplements, or perhaps, and preferably, a change of habits. For a healthy adult to take multi-vitamins sounds to me like hedging your bets, but a pill a day won't get you intoxicated either. | {
"source": [
"https://skeptics.stackexchange.com/questions/299",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/64/"
]
} |
303 | Some time ago I read a warning that microwaved water can "explode" under certain circumstances. There was one case as an example where someone heated water in the microwave, took it out and then it "exploded" causing him to be burned. Can something like this really happen, and if yes, under which exact circumstances? | Yes , this can happen with water, and in fact other liquids as well. According to the UNSW School of Physics , this is called superheating , and it occurs when a liquid is heated to a temperature slightly above its boiling point without the liquid starting to boil. The result is an unstable liquid that can boil (steam) violently when a foreign object (i.e. instant coffee, tongue, spoon, etc.) contacts the liquid (I'll explain how/why later in this answer). This violent boiling is the " explosion " referred to in your question, and it can be quite dangerous. (Note that this is not, by definition, an actual explosion , but colloquially, it may be referred to as such. See the comment by dm.skt below.) Superheating occurs when a liquid is heated in a smooth container*, such as a brand-new mug or bowl, for a long time in a microwave. The smooth container prevents steam bubbles from forming on the surface of the container as the liquid is heated. The formation of steam bubbles is a crucial step of boiling; without steam bubbles, the liquid cannot boil , and this is why superheating is possible. Introducing a non-smooth object into superheated water allows the water to form steam bubbles on the irregular surface of the object, leading to a potentially rapid boil of the water. * Note : As a container is used and/or washed, microscopic abrasions and scratches will accumulate on the interior surface of the container, whether from stirring with a spoon or scrubbing. Thus, the likelihood of superheating occurring with any given container decreases each time the container is used and superficially scratched, because steam bubbles will form more easily the more scratches are present. | {
"source": [
"https://skeptics.stackexchange.com/questions/303",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
315 | I doubt that organisms have electromagnetic (EM) fields. If we did have such a field, then we would certainly be susceptible to having electric currents induced in us by stronger EM fields. Or worse, being affected by magnetic fields like a scrap of iron. Do any organisms actually have such a field? Where does this claim come from? Edit: This question arose because of this question. | They have plenty of EM fields ! Atoms are held together by the electromagnetic field Chemistry is based on electromagnetism The body emits heat through electromagnetic radiation There are currents which flow around muscles and the nervous system . We are affected by the EM field: Through light Through radiative heat Through radiation in general | {
"source": [
"https://skeptics.stackexchange.com/questions/315",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/43/"
]
} |
328 | As a parent, I often hear people say that they think it's bad for their children to have several vaccines in one go. Some parents pay for some vaccines to be given separately, and I wondered if there is any evidence that it makes a difference. | This argument, "Too many, too soon", is very common among groups opposing vaccines and promoting alternative cures. The basic argument is that the number of vaccines given to children increased substantially and that this "overloads" the immune system and causes illnesses, e.g. autism. I've heard this claim almost exclusively in connection with autism, so I'll focus on that in my answer. The number of vaccines you can find in the recommended vaccine schedule for the United States published by the CDC. But in the end the number of vaccines is nothing compared to the number of antigens children will encounter naturally. Paul Offit said the following about that subject: A baby’s body is bombarded with
immunologic challenges—from bacteria
in food to the dust they breathe.
Compared to what they typically
encounter and manage during the day,
vaccines are literally a drop in the
ocean”, and Dr. Offits studies
theoretically show an infant could
handle up to 100,000 vaccines at one
time … safely ( quoted from SBM ) There is a study published in the Journal of Pediatrics titled "On-time Vaccine Receipt in the First Year Does Not Adversely Affect Neuropsychological Outcomes" that directly refutes the claim that too many vaccines cause neurodevelopmental disorders in children. From that study: Timely vaccination during infancy has
no adverse effect on
neuropsychological outcomes 7 to 10
years later. These data may reassure
parents who are concerned that
children receive too many vaccines too
soon. On rereading the question I see that I misread it somwhat, but I think the evidence also holds true for the case of simultaneous vaccinations, and the CDC agrees with that . | {
"source": [
"https://skeptics.stackexchange.com/questions/328",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/92/"
]
} |
351 | You hear a lot of claims that, once you include manufacturing and battery replacement, hybrids pollute more than an efficient, more conventional engine . Are there any end-to-end studies measuring any type of pollution for both types of vehicles, which demonstrate that one is superior, even when the manufacturing (and pollution to generate electricity) is included for consideration? Note, I'm not talking about comparisons to Hummers. Pollution to include CO 2 and other emissions commonly attributed to and regulation in relation to the combustion of gasoline in motor vehicles. | If you asked about Nickel Metal Hybrid batteries, the answer would be extremely easy. A large amount of studies have been done with these, usually concluding that they have lifespan comparable to those internal combustion engine vehicles. To cite the 100,000-Mile Evaluation of the Toyota RAV4 EV study , The five-vehicle test is demonstrating the long-term durability of Nickel Metal Hydride batteries and
of electric drive-trains. Only slight performance degradation has been observed to date with the
highest mileage vehicles. Test data provide strong evidence that all five vehicles will exceed the
100,000-mile mark and SCE’s positive experience points to the very strong likelihood of a 130,000 to
150,000-mile battery and drive-train operational life. This is achieved by full or mostly full range use
after every charge. EVs can therefore match or exceed the lifecycle miles of comparable internal
combustion engine vehicles. As such, the reduction of greenhouse gases is simply a net benefit for the environment. However, you asked for lithium-ion batteries. That makes the answer harder to answer. Lithium-ion batteries are used in hybrid cars since only very recently. Little information is available on the subject. Don't take my word for it. It's the first thing said in the only peer-reviewed study I could find on the subject , published in August 2010: Battery-powered electric cars (BEVs) play a key role in future mobility scenarios. However, little is known about the environmental impacts of the production, use and disposal of the lithium ion (Li-ion) battery. This makes it difficult to compare the environmental impacts of BEVs with those of internal combustion engine cars (ICEVs). The study made several assumptions that were favorable to ICEVs: Used a car more energy efficient than the average car sold in Europe in 2009. They used 5.2 L of gasoline per 100 km, instead of 5.7 L of diesel /100 km 6.6 L of gasoline /100 km. "All expenditures for the exploitation of the lithium salts were allocated to the lithium salts, even though the saline brine yields other byproduct as well." All the burden from production are allocated to the first life of each product even though the product might be reused or recycled. As explained in the study, this assumption heavily penalizes BEVs since recycling of electric batteries is high and since recycling of lithium is more energy efficient than production of it. In spite of that, electric cars perform far better than conventional cars on all four indicators (abiotic depletion potential, global warming potential, cumulative energy demand, and eco-indicator 99): In fact, the research concludes that All the facts taken together, the results of the LCA, the various sensitivity analyses, the modeling applied for EOL, the assumption for the used electricity mix, etc., suggest that E-mobility is environmentally beneficial compared to conventional mobility. The Li-ion battery plays a minor role in the assessment of the environmental burden of E-Mobility. Thus, a Li-ion battery in an BEV does not lead to an overcompensation of the potential benefits of the higher efficiency of BEV compared to an ICEV. They note, however, that it's not always necessarily always the case. A few very small and efficient internal combustion engine vehicles can perform as well as electric cars: A break even analysis shows that an ICEV would need to consume less than 3.9 L/100km to cause lower CED than a BEV or less than 2.6 L/100km to cause a lower EI99 H/A score. Consumptions in this range are achieved by some small and very efficient diesel ICEVs, for example, from Ford and Volkswagen ( 13 , 39 ). They also note that the means by which the energy is produced influences the how environmentally-friendly BEVs are. The study used the average electricity production mix in Europe to give a general idea. If electricity comes from "an average hard coal power plant", the environmental burden is increased by 13.4%. On the other hand, if the electricity comes from hydropower plants, the environmental burden is decreased by 40.2%. As such, as countries move toward green energy, the environmental burden of electric cars will decrease. The study does not address the cost of manufacturing the automobiles, but those costs are not significant. As a recent Argonne National Lab study concluded that, while hybrid cars cost more to produce, hybrid cars make up for their greater manufacture energy costs by being more environmentally-friendly on the road - especially if recycled materials are used in the vehicle's fabrication. To cite the study's conclusion, The energy use and GHG emissions that result from vehicle production and disposal of advanced-powertrain vehicles (HEV and FCV) may be greater than those for ICEVs because of (1) the use of energyi-ntensive materials in the fuel cell system of the FCV, and (2) the increased use of aluminum in both the HEV and FCV. However, the use of recycled materials can reduce these impacts. Conversely, the use of energy-intensive materials such as aluminum and carbon fiber composites does not necessarily increase the vehicle-cycle energy use and GHG emissions of lightweight vehicles; with a reduction in total weight, the results are about the same and could be improved with additional recycling. To put vehicle-cycle results into a broad perspective, we conducted a total energy-cycle analysis that included the vehicle-cycle, fuel-cycle, and vehicle-operation stages. Our vehicle-cycle analysis revealed that lightweight materials can reduce the weight of a vehicle and improve its fuel economy, but that production of these materials can be energy intensive if recycled materials are not used. Our total energy-cycle analysis further shows that, when examining vehicle technologies and lightweight materials on a total energy-cycle basis, there can be a significant net benefit in terms of energy use and emissions reduction by substituting lightweight materials for conventional materials. | {
"source": [
"https://skeptics.stackexchange.com/questions/351",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/34/"
]
} |
361 | I remember reading not too long ago about a study in which experimenters performed a number of standard psychological tests with a twist; it was something about they ran a number of tests from standard psychiatric batteries but they ran them backwards, and so were able to measure a small but positive 'esp' effect in which the participants were able to remember slightly better words from a larger group of words that they would be told only later. I am not sure if the study was peer reviewed or published in a serious journal or what. My question is whether there is any serious scientific support at all for any kind of telepathy (or clairvoyance, cryptomnesia, etc)? | No, there is no serious scientific support for any of these. Some studies, even well designed, do sometimes see some sort of statistically significant effect, but the majority of studies do not (ref meta studies ). And if these phenomena were real, you would expect some people to be better at it than others, and no such people have been found . This all illustrates the scientific importance of results being reproducible and should teach journalists to stop basing scary claims about this and that on a single study. | {
"source": [
"https://skeptics.stackexchange.com/questions/361",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/187/"
]
} |
370 | A couple of months ago I watched the talk " Sugar: The Bitter Truth " by endocrinologist Dr. Robert Lustig on YouTube. The overall tone of the talk raised a couple of red flags; it sounded a little too much like conspiracy mongering for my taste, but the claim that Dr. Lustig makes is a pretty simple one: fructose doesn't only fatten us up; it's a toxin that gets metabolized very similar to ethyl alcohol. Conclusion: high fructose corn syrup and sugar should be avoided. Have the claims of Dr. Lustig ever been independently verified or is this a one man crusade against the evil nutrition empire? | Especialy High Fructose Corn Syrup (HFCS) is a very "out there" worry for some people it seems. And also incorrectly. The key, as always, is moderation and looking at the real world. A good read is this Science-Based Medicine article . The best quote you can probably get out of it is the ending sentence: And stop worrying that HFCS is poisoning you and your children. The point is made in the intro that we are not just looking at fructose/HFCS. It starts with this supporting claim (referenced) Despite the fact that some of the underlying mechanisms are not clear, the evidence seems pretty solid that there are real risks to high fructose consumption . But don't stop there, because here is the kicker: However, the question remains — is HFCS more of a health risk than other sweeteners? There is a lot of information in the article, and I suggest you read it to completely understand the sugar problem, instead of the "quick-win" frights that are raised on typical places. One of the things mentioned is this (emphasis mine): HFCS allowed food manufacturers to use less sugar — and thus fewer sugar calories — in their products without compromising sweetness. So it is probably not the healthiest - just like all sugar - in high concentration, but although there is truth in the problems with fructose, it is hardly a big problem compared to your intake. Worry about other things, like a balanced diet. | {
"source": [
"https://skeptics.stackexchange.com/questions/370",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/192/"
]
} |
377 | It is claimed in many different pseudoscience publications and sites that it was impossible for the ancient Egyptian civilization to build the pyramids, because: too much labour was needed it was impossible to cut stone with such precision they were built with particular geographical orientations that required knowledge they didn't possess etc This is probably due to the fact that we don't exactly know how the pyramids were built in the first places. There are different conflicting theories . Is Wikipedia misleading me here? Is there an accepted historical version of how the pyramids were built that can be used to effectively debunk the pseudoscience? | ScienceDaily has a nice article on this, as well as many related articles. In the cited article, they state: But the process of building pyramids, while complicated, was not as colossal an undertaking as many of us believe, Redford says. Estimates suggest that between 20,000 and 30,000 laborers were needed to build the Great Pyramid at Giza in less than 23 years. By comparison, Notre Dame Cathedral in Paris took almost 200 years to complete. I think what gets people so confused is they mistake old cultures for being unintelligent. Humans have had the same level of intelligence for nearly 200,000 years, just not the full benefit of technology. (Citation: Hominid Brain Evolution Testing Climatic, Ecological, and Social Competition Models, Drew H. Bailey & David C. Geary, Hum Nat (2009) 20:67-79, DOI 10.1007/s12110-008-9054-0) Furthermore, in the article, it states "laborers". A common misconception is that slaves built the pyramids, which is not the case. Archaeological evidence shows the builders were skilled and paid for their efforts. From the same article: the image most people have of slaves being forced to build the pyramids against their will is incorrect. An additional collection of articles can be found at this Discover Magazine Blog post by Andrew Moseman. It starts out saying: Forget the myths about massive numbers of slaves or Jews building the great pyramids, Egypt‘s chief archaeologist argues this week. He says Egyptian researchers have found the tombs of more pyramid builders, and in those tombs more evidence that free men erected these monumental tributes to the ancient pharaohs. And continues with numerous links to even more articles. As to the assertion that it was impossible to do many of the things that the builders of the pyramids did, that is a common misconception people seem to have. Most people don't consider ancient humans to have been as intelligent as we are, when in fact they possessed the exact same intellect as we do today, just not the technology. And since we rely so much on advanced technology, many people make an argument of incredulity because we just don't do things the old fashioned way. Some people have started to collect reconstructions of those methods on the web . The same argument regarding the mathematical precision could be made. Also, in ancient times, without our calendars and clocks, astronomical observations played a much more important role than today (i.e. when to plant, when to expect rains, etc.). Again, ancient humans were not stupid. | {
"source": [
"https://skeptics.stackexchange.com/questions/377",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/96/"
]
} |
399 | I've heard lots of people say things like "race doesn't exist" and "race has no biological meaning." On the other hand, I've heard lots of disagreements too, from scientific popularizers like Steven Pinker & Razib Khan. The Wikipedia article on race is distinctly bloated and unhelpful. What's the latest scientific consensus in regards to the biological meaning of human races? | These are quotes from Lynn B Jorde's & Stephen P Wooding's paper Genetic variation, classification and 'race' . Genetic variation is geographically
structured , as expected from the
partial isolation of human populations
during much of their history. Because
traditional concepts of race are in
turn correlated with geography, it is
inaccurate to state that race is
"biologically meaningless" . On the other hand, because they have
been only partially isolated, human
populations are seldom demarcated by
precise genetic boundaries . Substantial overlap can therefore
occur between populations,
invalidating the concept that
populations (or races) are discrete
types . Modern human genetics can deliver the
salutary message that human
populations share most of their
genetic variation and that there is no
scientific support for the concept
that human populations are discrete,
nonoverlapping entities . It depends on how you define "race": geographically, genetically, socially. But either way, you'll almost always find an "overlap" between populations. | {
"source": [
"https://skeptics.stackexchange.com/questions/399",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/200/"
]
} |
402 | What evidence is there for or against acupuncture being an effective treatment? | Acupuncture is based on the belief that diseases are caused by blockages of your qi, which flows in so-called meridians in your body. By sticking needles into those meridians you can manipulate the flow of qi and eliminate the blockages. The concepts of qi and meridians are unscientific, they date back to a time where there was no scientific method and knowledge of human anatomy was practically nonexistant. There is no evidence that qi and meridians exist at all. Sticking needles into your body still could have some effect, although it will have nothing to do with your qi. There are tons of clinical studies about acupuncture, but few conclusive results. A major problem is that controlling for the placebo effect is complicated, as people usually notice whether you stick needles into them or not. Some of the newer and better clinical trials used fake acupuncture needles that do not penetrate the skin. Another often used method is to stick the needles outside of the "proper" acupuncture points as a control. Acupuncture is believed to be helpful in a large variety of conditions, I'll take pain relief as an example as it is somewhat plausible that sticking needles into your skin could have an effect on the perception of pain. A review from 2009 in BJ concludes: A small analgesic effect of
acupuncture was found, which seems to
lack clinical relevance and cannot be
clearly distinguished from bias.
Whether needling at acupuncture
points, or at any site, reduces pain
independently of the psychological
impact of the treatment ritual is
unclear. My conclusion is that acupuncture is just a particularly effective placebo. | {
"source": [
"https://skeptics.stackexchange.com/questions/402",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/188/"
]
} |
415 | Salt is sometimes known as "white death" due to the belief that an excess intake of salt can cause substantial damage to health. What evidence exists to support or contradict the idea that excess salt intake can cause substantial health damage? Is it better to avoid salt altogether? | Toxicity of a substance must be investigated in different ways: Acute toxicity This corresponds to taking a large dose all at once. In the case of sodium chloride, toxic effects are encountered at 500-1000 mg/kg body weight. The effects include vomiting, ulceration of the gastrointestinal tract, muscle weakness and renal
damage, leading to dehydration, metabolic acidosis and severe peripheral and central neural effects. The estimated fatal dose of sodium chloride is approximately 750 to 3000 mg/kg. Also see ( 1 , 2 ) for many more sources. Chronic toxicity This includes non-carcinogenic effects on health. There seems to be a link between salt intake and some hypertrophy of the heart - which is a risk factor for heart disease. The generally known medical advice to use less salt is actually due to a different factor: reducing salt reduces blood pressure in hypertonic subjects. In other words, if you have high pressure, then reducing salt is beneficial. The effect of reducing salt in individuals with normal pressure instead is disputed . Reduction of dietary sodium is generally recommended as a nonpharmacological treatment for patients with essential hypertension. In normotensive adults a significant
reduction in sodium intake is needed to achieve a modest reduction in blood pressure. Carcinogenic effects Salt has no known carcinogenic effects and no carcinogenic effects are expected to be found ( 1 , 2 ). | {
"source": [
"https://skeptics.stackexchange.com/questions/415",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/123/"
]
} |
450 | I have heard this one several times but was never given a convincing explanation. Is this a real phenomenon? (Bonus points for a good physical description of the behavior or reasons it couldn't occur.) | This phenomenon has been widely attributed to the Coriolis Effect . The Wikipedia article has a fairly wordy summary of the effect, so I will instead quote from this page (emphasis mine): The Coriolis Effect is the observed curved path of moving objects relative to the surface of the Earth. Hurricanes are good visual examples. Hurricane air flow (winds) moves counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere . This is due to the rotation of the Earth. The Coriolis force assists in setting the circulation of a hurricane into motion by producing a rightward (clockwise) deflection that sets up a cyclonic (counterclockwise) circulation around the hurricane low pressure. (If you are interested in reading further about the details of the Coriolis Effect itself, I would encourage you to read some of the Wikipedia article, as it goes into great detail.) As several sources indicate, the Coriolis Effect is not strong enough in bodies of water such as those in bathtubs, sinks, toilets, etc. to reliably influence their rotational direction as they drain. The rotational direction of water in such containers is much more likely to be affected by any combination of the following: Pre-existing movement of the water. If the water was already rotating (if even very slowly) before being drained, this will almost certainly affect its rotational direction as it drains. The geometrical shape of the container. The smoothness of the container. The location of the drain. The Wikipedia article on the Coriolis Effect does mention a 1908 experiment in which a physicist successfully demonstrated the effect with a large tub of water (more than 1000 liters). When the plug was pulled, the water eventually began to rotate in a counter-clockwise direction (same as hurricanes in the northern hemisphere, where the experiment took place). However , the tub used was circular, with a tiny central drain, and the experimenter took great care to eliminate as many disturbances as possible from the water before draining it. So, if your sink/toilet/bathtub is sufficiently large, circular, has a tiny central drain, and you let the water completely stop moving before you drain it, you would observe that the rotational direction of the water as it drains is influenced by the Coriolis Effect (i.e. varies by hemisphere). But for the other 99.9999% of the sinks/toilets/bathtubs in the world, the direction in which the water rotates is determined by something else. | {
"source": [
"https://skeptics.stackexchange.com/questions/450",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/187/"
]
} |
453 | I've heard it numerous times, that in the old days people thought that the world was flat. Most commonly I heard this in connection with the voyage of Columbus, that he believed the earth to be a sphere while most other people thought he must fail to reach India as the world is flat. Is there any direct evidence, e.g. written documents, that shows when people first knew that the earth is a sphere? And since when was this common knowledge in the educated population? | According to Dr Karl , it was known that the earth was a sphere as far back as Aristotle. The three reasons were: The top of the mast being sighted before the rest of the ship Lunar eclipses always throwing a circular shadow The rising of the high point of certain constellations as one travels further south The scientists thought Columbus's voyage would fail, not because they thought the earth was flat, but rather because he would have to travel 20000 nautical miles, rather than 5000. So, for the last 2500 years, in Europe
and in the Middle East, the
flat-earthers were in a very small
minority. At least, this is what the
historian Jeffrey Burton Russell, of
the University of California at Santa
Barbara, reckons. His book, In Inventing the Flat Earth ,
claims that since the third century
BC, practically all educated people in
the western world believed in a
spherical earth. Looking as a historian into the
historical record, he found tens of
thousands of Christian theologians,
poets, artists and scientists who
believed that the earth was a sphere. On the other hand, he could find only
five Christian authorities who
believed in a flat earth. The Straight Dope also discussed this. | {
"source": [
"https://skeptics.stackexchange.com/questions/453",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
460 | I have heard several claims that we have enough nuclear weapons to wipe out all of humanity, but has anyone actually done an exact calculation of whether we do? The claim includes: All of the nuclear weapons which are currently built by the whole of humanity (according to available statistics). All the direct deaths due to exploding them in the most damaging way (caused by the blast, fallout, radiation poisoning, nuclear winter and whatever other direct consequences that can be accurately predicted) | Check out this app which lets you figure out what happens if a bomb went off in your city . There is also one here at the federation of american scientists . This site talks about the nuclear clouds and how much sunlight would be blocked . The radiation is what you really need to worry about . | {
"source": [
"https://skeptics.stackexchange.com/questions/460",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/188/"
]
} |
466 | I was cautioned by mom that I mustn't go swimming when there is lightning; the theory is that it is more likely for lightning to hit you when you are in the water. Is this fear justified? | The theory, the way I've understood it, is that you're more likely to be the highest elevated point, when you're in the water, since there are rarely any surrounding tall objects, such as trees. This is more likely to be true for a boat than for a person swimming, obviously. This is the same warning as that with regards to standing near a tree during lightning. The reasoning is that you should get away from tall objects, and certainly not comprise one yourself, during lightning. The rationale for this is that an electrical discharge always seeks out the shortest path to ground. Shortest path, here, refers in part to the physical distance between the lightning source and the target, but also to resistance - if there's something more conductive in the vicinity of the highest point, this might be the lightning target instead. There is no reason to expect this shouldn't hold true for lightning - indeed, it is by this premise a lightning rod works - but to the extent that it does, it does so rather crudely. Not infrequently does lightning strike very close to a lightning rod, without hitting it, despite the rod being the highest elevated point. When swimming, attracting lightning strikes to your direct vicinity can be just as fatal as attracting a strike immediately to yourself, which is my next point: So much for the risk of being hit. Another concern with swimming during a lightning storm is the danger of any lightning strike, regardless of whether or not it hits you. On land, it's quite easy to see to it that you're relatively safe. Inside a car, for instance, you're protected since you're inside a conducting enclosure (see Gauss's Law ). Non-distilled water is a good conductor, which means you could be in danger if lightning strikes in your vicinity, not only if it hits you. The best source I've found for that is some dude who's apparently a lightning researcher in Argonne , who says: My guess is that the average lightning strike would electrify a few hundred feet worth of water from it's strike point sufficiently to electrocute someone. Note that the Straight Dope suggests a radius of twenty feet or so. | {
"source": [
"https://skeptics.stackexchange.com/questions/466",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/214/"
]
} |
487 | Some people believe that smoking marijuana (without any tobacco) is harmful to your health and may cause problems. Examples of things I've heard weed supposedly causes: All the health problems of tobacco (cancer, strokes, etc) You get addicted to it and can't stop It fries your brain If you smoke too much you can die I know for a fact that the last one is false, as the scientific consensus is that an overdose of marijuana in a human being is for all intents and purposes impossible. I'm not sure what "frying your brain" even means, and I don't know about the first two. Has it been scientifically proven that weed is, or isn't, harmful? | It might be that smoking or ingesting marijuana has positive/neutral effects on certain health issues and neutral/negative effects on others. The consensus of studies are generally inconclusive in this regard. For example, there are studies that say there is a 100% full increase in the odds of suffering from schizophrenia after trying cannabis Others that say: "We hypothesized that there would be a positive association between
marijuana use and lung cancer, and
that the association would be more
positive with heavier use," he said.
"What we found instead was no
association at all, and even a suggestion of some protective effect. " "Earlier work established that marijuana does contain cancer-causing
chemicals as potentially harmful as
those in tobacco, he said. However,
marijuana also contains the chemical THC, which he said may kill aging cells and keep them from becoming
cancerous ." - Link to Washington
Post Article and more recently: Moderate Marijuana Use Does Not Impair Lung Function, Study Finds Other studies have been conducted on the specific interaction between THC and cancer cells. This study , conducted by the Journal of Clinical Investigation states that: ...THC can promote the autophagic
death of human and mouse cancer cells
and provides evidence that cannabinoid
administration may be an effective
therapeutic strategy for targeting
human cancers. Again, I am not overlooking the potential health risks that have been proven to be associated with marijuana use, but I think it is a complex issue and media reports typically focus on potential negative health effects of marijuana use without mentioning potential positive health effects. I think this graphic helps illustrates my point about the media reports: | {
"source": [
"https://skeptics.stackexchange.com/questions/487",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/253/"
]
} |
490 | Many people believe that if you shave or - especially - wax your legs, arms, chest, pubic hair or armpits then the hair will grow back stronger, or thicker, or more black, or more rapidly, or any combination of those. Is it actually true? | According to a Mayo Clinic dermatologist , no , it is a myth. Both he and snopes.com point to the fact that after cutting or otherwise removing hair, it grows back in feeling coarse and stubby to the touch. This can lead to the perception that the hair is stronger or thicker, when in reality, it's the same as it always was, just shorter and with rougher ends. After the hair grows out again naturally, the hair will likewise seem smoother, because hair tapers when not cut. | {
"source": [
"https://skeptics.stackexchange.com/questions/490",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/253/"
]
} |
525 | Vegetarianism is heavily promoted. But let's say all people on Earth stop eating animal products. Can we grow enough crops so all people on the Earth are provided with enough healthy, nutritious food? The question is of course very theoretical, but without discussing future possibilities to cultivate deserts and oceans, is there enough space to grow enough crops? | The production of meat is much less efficient than the production of the crops the animals eat. If you would use all the grain to feed people directly instead of producting meat, it has been estimated that the US could feed about 800 million people with that grain . One paper about "Sustainability of meat-based and plant-based diets and the environment" states that For every 1 kg of high-quality animal
protein produced, livestock are fed
about 6 kg of plant protein. The production of meat is clearly less efficient than directly producing and eating plants. So it would be much easier to feed the world population on a vegetarian diet than with a meat-rich diet. | {
"source": [
"https://skeptics.stackexchange.com/questions/525",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/123/"
]
} |
564 | There is a widespread belief that one chooses to be a homosexual , and that people can successfully overcome such feelings . On the other hand, some scientific studies have shown that finger length may be linked with sexuality : It has long been suspected that high levels of
androgenic steroids in the uterine environment have
a musculizing effect on the fetus. Furthermore, several psychiatric organizations claim it is not a choice, but disagree on whether it is completely innate, affected by early childhood, or whether we really have any clue at all! So, as far as we know now, is homosexuality a matter of choice, nature, or nuture? | Here is a good breakdown from a grad student on twin studies . However, the key thing to note reading through it is the re-iterated theme that most research to date has not been of a sufficient sample sizes to be able to claim to represent homosexuality in general. How we define "homosexuality" is also very much up in the air, particularly with prison populations. When do two inmates having sex count as homosexual? As far as we know, from a truly skeptic viewpoint, we just don't know yet what "causes" homosexuality . I will add, as an aside, that this is insanely hard to research. 95% of all pages I get are strongly activist for or against. | {
"source": [
"https://skeptics.stackexchange.com/questions/564",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/334/"
]
} |
569 | Is there evidence for a correlation between the use of mobile phones and the occurence of brain cancer? If yes, is there also evidence for causality? | This study of 420,000 danes found no correlation between mobile phone use and instances of cancer. We found no evidence for an association between tumor risk and cellular telephone use among either short-term or long-term users. Moreover, the narrow confidence intervals provide evidence that any large association of risk of cancer and cellular telephone use can be excluded. | {
"source": [
"https://skeptics.stackexchange.com/questions/569",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/-1/"
]
} |
570 | Of course, I think I can safely assume if an eye is left pointing directly towards sun for a long period of time it does get major damage. However, staring at the sun also hurts very quickly. That pain seems like a very natural * defense mechanism against eye damage. Also, I guess technically even a very quick glance at the sun does cause temporary eye damage, as there is a visible distortion spot in sight for a short while afterwards. So the question is: Is possible for someone to naturally stare at the sun for an amount of time required for significant permanent eye damage, or whether the pain will become too much significantly sooner than any such damage would happen? Then: If not, is it possible with simple willpower, without special training or medication, to force oneself to ignore the pain for a long enough time to cause such damage? Also: Is there a difference in this between adults, children and babies? And as a bonus, are there any special environmental situations where this does not apply? For example: sunset, sunrise, solar eclipse, major fog, underwater, or light filtered through something else. * - Natural is here not in the sense of "everything natural is good", but in the sense of "it is reasonable to assume there would be an evolutive advantage from it". | An ordinary person can easily stare at the sun or a solar eclipse long enough to cause significant, possibly permanent loss of vision. Looking directly at the sun for even brief periods of time may cause
blindness or severe damage to the
eye. Solar retinopathy, damage to
the eye’s retina due to solar
radiation, and blindness to varying
degrees and persistence frequently
result from sungazing during a solar
eclipse. Although vision loss due to
this damage is generally reversible, permanent damage and loss of vision have been reported. Most eye care
professionals advise patients to avoid
looking directly at the sun. Exposure to ultraviolet radiation, produced by the sun, is associated
with damage to the eye, including
pterygium and cataracts. ( Sungazing ) Phil Plait recently cited an ‘‘unprecedented rise in the number of cases of solar retinopathy’’ directly linked to a popular Irish shrine where people stared at the sun in order to experience ‘‘visions of the Virgin Mary’’. ( Plait ) | {
"source": [
"https://skeptics.stackexchange.com/questions/570",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/154/"
]
} |
575 | Does Myers-Briggs Type Indicator tell something objective and predictive about the persons decision making tendencies? In other words, can a Myers-Briggs score give you useful information about what decisions a person is likely to make in future scenarios, or about his/her abilities? | Actually, there is little evidence to support that the Myers-Briggs gives us much useful information, at all. The M-B was based on Jungian ideas, but the people who developed it were not even psychologists. They based the questions on a variety of things, only some of which can be linked to Jungian ideas on psychology. Jungian ideas have not necessarily been supported, consistently, when tested. The test, itself, has shown to be problematic in determining behavior simply because people's results are often inconsistent. Basically, the MB test is a very widely used measuring tool which hasn't been proven to be either consistent or even very useful. There's a decent breakdown of the history of the test and its flaws at skepdic, here . | {
"source": [
"https://skeptics.stackexchange.com/questions/575",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/79/"
]
} |
598 | I have been following this question casually over the past couple of years, and it seemed to me that there was no strong consensus either way on the subject. However, I recently read an editorial from one of the scientists involved in the Supreme Court case, Schwarzenegger vs. EMA, arguing that the evidence for psychological and physical damage to children is strong. On the other hand, a quick check of the wikipedia article on the subject seemed to confirm my original impression, that there was still significant controversy on the subject. | We don’t know . 1 Despite many studies conducted, so far no consensus has emerged whether violent video games cause a long-term, sustained increase in violent behaviour. On the other hand, it seems increasingly likely that if such an effect exists, it is probably small: at most, video games have a minor overall influence on violent behaviour. Wikipedia has a break-down of the discussion with references to the relevant studies. Given the wide variability of individual studies’ results, the best available evidence is summarised in meta-analyses, of which there are also several. But even these meta-analyses reach different conclusions, partially because there’s disagreement even about the correct meta-analysis methodology. Some of the scientific publications in this area are unusually vitriolic, and personally attack other scientists (on both sides of the debate). So here’s a representative (rather than exhaustive) overview of different conclusions, focussing on the more recent meta-analyses. A 2010 study by Craig A. Anderson & al. concludes that [t]he evidence strongly suggests that exposure to violent video
games is a causal risk factor for increased aggressive behavior,
aggressive cognition, and aggressive affect and
for decreased empathy and prosocial behavior. And that playing violent video games is a significant risk factor for both short-term and long-term increases in physically aggressive behavior. The study was variously criticised based on a number of methodological flaws. In particular, one reanalysis by Joseph Hilgard & al. points out that unaccounted-for publication bias decreases the evidence, potentially rendering it non-significant. The original authors acknowledge some of these shortcomings but stand by their original conclusion. A 2015 study by Christpher J. Ferguson reached pretty much the opposite conclusion: that video game influences on increased aggression […] are minimal. The meta-analysis spends significant time identifying weaknesses in existing studies, and attempts to work around these, in particular publication bias. This study was published alongside multiple reviews which both support and criticise the study. One criticism in particular is the original study’s reliance on controlled effect sizes which, in a nutshell, attempt to account for independent factors that influence the effect size (= the magnitude of the measured effect). Proponents of using controlled effect size point out that lack of controlling for these independent variables is known to over-inflate effect size ( Patrick M. Markey, 2015 ). Ferguson includes the following example: boys play more violent video games […] and are also more aggressive than girls. Thus, one is likely to see bivariate correlations between video game violence use and aggression that are simple gender effects Detractors such as Paul Boxer & al. (2015) and Hannah R. Rothstein & Brad J. Bushman (2015) contend that this kind of adjustment is “unreliable and invalid” because it “overcorrects”, and “because the statistical theory underlying meta-analytic procedures assumes that one is working with raw (zero-order) correlations” ( Anderson & al. , 2010 ) — in other words, use of controlled effect sizes violates the assumption that effects such as those in the above example do not exist. 2 In a reply , Ferguson calls these claims “problematic both statistically and theoretically”. Finally, Ferguson’s meta-analysis was subsequently defended on theoretical grounds (in particular regarding the use of controlled effect sizes) as well as reanalysed in 2016 by Luis Furuya-Kanamori & Suhail A. Doi using “improved meta-analytical model” (to invalidate the main criticism discussed above). This study confirmed the main results of Ferguson’s meta-analysis. There was a significant yet very small effect on aggressive behavior of exposure to both general […] and violent […] video games. A 2020 study by Aaron Drummond & al. focussing on long-term effects found that [o]verall, longitudinal studies do not appear to support substantive long-term links between aggressive game content and youth aggression. Correlations between aggressive game content and youth aggression appear better explained by methodological weaknesses and researcher expectancy effects than true effects in the real world. And effect sizes were lower for better-designed studies and those with less evidence for researcher expectancy effects. That is: the higher quality the study, the less evidence for a causal effect of violent video games on violent behaviour. Given the wide variety of conclusions from research studies, it’s instructive to survey the opinion of researchers in the field. This was done by Brad J. Bushman & al. in 2015 . Their conclusion is: Although a few vocal researchers claim there is a “debate” on this issue, the overwhelming majority of researchers believe that violent media increase aggression in children, and that the relationship is causal. Notably, they surveyed not only the effect of video games but of other types of “violent media” as well, including “violent literature” and “violent music”, which the majority of researchers also believes can increase aggression. Conversely, there is no majority who believes that this causal effect is a “major factor in real-life violence”. In other words: even though most believe there is an effect, most either believe that this effect is ultimately not a major factor, or don’t know: (Numbers from Brad J. Bushman & al. (2015) ) 1 This was written in 2011, and depressingly the answer hasn’t really changed, though the number of studies has. One thing that has changed is that studies have become less likely to argue for large, causal effects. 2 Stated like this, the claim seems obviously false, since it is clearly contradicted by the example. However, it’s not that simple: the statistical model underlying meta-analyses uses a simplifying assumption . The simplifying assumption may produce false results because it does not reflect reality, as argued e.g. by Ferguson. However, on the flip side, when using different assumptions one needs to adjust the statistical model. His critics claim Ferguson has not done this: he continues to use a statistical model that assumes different inputs from what he provides by controlling the effect size. | {
"source": [
"https://skeptics.stackexchange.com/questions/598",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/369/"
]
} |
610 | Lately, I've been watching the Libyan civil war in the media, and both sides in the conflict often celebrate success by firing their AK-47 s into the air. Not to say that firing guns into the air is restricted to any particular group, I'm just using this as an example. Will bullets fired into the air by small arms fire have the velocity to kill a person when they fall? | As for physics, it is really very simple, the kinetic energy is converted to a potential energy while climbing and then to kinetic again when falling, with some of it converted to a heat due to friction. The air friction is quite substantial, the landing velocity, which is reported to be in range 50-200 m/s, is significantly lower than muzzle velocity, which is usually 300-1000 m/s, but the velocity is still high enough to kill. Celebratory gunfire - plenty of statistics and examples. My favourite: "every bullet that is fired up, must come down". People are injured, sometimes fatally, when bullets discharged into the air fall back down. The mortality rate among those struck by falling bullets is about 32%, compared with about 2% to 6% normally associated with gunshot wounds. The higher mortality is related to the higher incidence of head wounds from falling bullets. For example, in one study led by the U.S. Centers for Disease Control and Prevention (CDC), they found that 80% of celebratory gunfire-related injuries are to the head, feet, and shoulders. In the U.S. Commonwealth of Puerto Rico, about two people die and about 25 more are injured each year from celebratory gunfire on New Year's Eve, the CDC says. Between the years of 1985 and 1992, doctors at the King/Drew Medical Center in Los Angeles, California, treated some 118 people for random falling-bullet injuries. Thirty-eight Kuwaitis celebrating in 1991 at the end of the Gulf War by firing weapons into the air caused 20 deaths from falling bullets. Firearms expert Julian Hatcher has studied falling bullets and found that on average .30 caliber rounds reach terminal velocities of 300 feet per second (90 m/s) and larger .50 caliber bullets have a terminal velocity of 500 feet per second (150 m/s). A bullet traveling at only 150 feet per second (46 m/s) to 170 feet per second (52 m/s) can easily penetrate human skin and at 200 feet per second (60 m/s), that same bullet can penetrate the skull. Even a bullet that does not penetrate the skull may still result in an intracranial injury. | {
"source": [
"https://skeptics.stackexchange.com/questions/610",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/49/"
]
} |
617 | When I used to live in Japan, the summers were really too much for me, especially when going to bed. The strange thing is that all the (Japanese) people would strongly advise me against leaving the air conditioner running while I sleep because this is somehow very bad for people's health. On the other hand, I also used to live in Thailand for a while, and I never heard anybody say something of that nature-- and their weather is steaming hot. Similar with other countries I've lived in. I only heard this air conditioner thing while in Japan. So my question is: Is there really anything at all to be concerned about when running the air conditioner while sleeping? Or is this more like a Japanese urban myth? By the way, I always used to set the air conditioner in air drier mode, rather than air cooler mode. It felt as cool, except that it was dry. | This is a common urban legend in South Korea as well. It's called "Fan death" though, see Wikipedia's fan death article ). Some quotes from that Wikipedia article outlines the otherwise outlandish claims that are associated with this phenomenon. Generally, many people die for various reasons, such as bad health, alcoholism, heart attack, etc. and it's easier to blame something external and unrelated. This is the main source and reason the myth propagates: Gord Giesbrecht, a professor of thermophysiology at the University of Manitoba in Canada, 14 is a leading expert on hypothermia: It's hard to imagine death by fan, because to die of hypothermia, one's body temperature would have to get down to 28 [°C], drop by 10 degrees [Celsius] overnight. We've got people lying in snowbanks overnight here in Winnipeg and they survive. Maybe if someone was elderly and they were sitting there for three days in a sealed room with an electric fan turned on. Someone is not going to die from hypothermia because their body temperature drops two or three degrees overnight; it would have to drop eight to ten degrees." In addition, "the only way to verify whether someone had really died of hypothermia during the night would be to take a core body temperature the following morning. Waiting three days while the body was in the morgue wouldn't work because the corpse's temperature can drop during that time. 2 Dr. John Linton at Yonsei's Severance Hospital, who attended medical school at Yonsei University, is licensed to practice medicine in South Korea: 2 There are several things that could be causing the fan deaths, things like pulmonary embolisms, cerebrovascular accidents or arrhythmia. There is little scientific evidence to support that a fan alone can kill you if you are using it in a sealed room. Although it is a common belief among Koreans, there are other explainable reasons for why these deaths are happening. Dr. Lee Yoon-song is a professor at Seoul National University's medical school and works with the school's Institute of Scientific Investigation. He has conducted autopsies on some of the people who have been described in Korean media as having succumbed to fan death: When someone's body temperature drops below 35 degrees, they do start to lose judgment ability. So if someone was hiking and later found dead, that could be part of the reason. But we can't really apply this to fan accidents. I found most of the victims already had some sort of disease like heart problems or serious alcoholism. So hypothermia is not the main reason for death, but it may contribute. He blames the Korean media for the persistence of the urban legend: Korean reporters are constantly writing inaccurate articles about death by fan, describing these deaths as being caused by the fan. That's why it seems that fan deaths only happen in Korea, when in reality these types of deaths are quite rare. They should have reported the victim's original defects such as heart or lung disease, which are the main cause of death in these cases. | {
"source": [
"https://skeptics.stackexchange.com/questions/617",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/403/"
]
} |
651 | In the movies, fingerprints identification always works, with no mistakes. How close is this to reality? | Properly done, the false positive rate is negligible (estimated under 1:60 billion) assuming that the axiom "fingerprints are individual" is correct in the first place. Using automated matching, the error rates are MUCH higher, especially on partial prints, which the police uses too. Because the false positive rate on those are known to be horrendous, all automated matches are verified manually (though that does not really make it any better). All in all, false positive rates of between 1% and 4% are not uncommon, depending on the investigator's diligence. You should note that identifying a person without doubt is not the intent of matching a fingerprint in the first place, nor is ruling out a possible suspect. A fingerprint match gives the police a "leverage" which may a) be used to justify breaking your civil rights (e.g. arrest, sequestration, body search) and b) gives their case a better "weight" when presented to the district attorney and later to an uncanny judge or jury, and c) press a culprit into confession as he realizes that there is doubtless evidence. Like most forensic "evidence" (such as a DNA sample), fingerprints don't really mean an awful lot, though they are often seen as "unquestionable". For example, your fingerprint on the knife that sticks out of a dead body can equally well mean that you've killed that person or that you've had that knife in your hands in the shop two days ago (you thought about buying one). Your DNA on a cigarette that was found at a crime scene can equally well mean you're the culprit and stupid enough to smoke mid-crime, but it could equally well mean you threw the cigarette on the street the day before, or someone took it out of the ash-tray in your favourite cafe, just to lay a false track against a random person. While it is true that often things indeed are what they look like, they need not be, and sometimes they aren't. However, it is usually assumed that the "evidence" is infalliable, which is an increasing problem in a society where the classic presumption of innocence has turned into "you must prove your innocence". EDIT (some sources were asked for): One source which is freely available online is Galton's somewhat dated book . Don't be put off by the fact that the book is 130 years old. Galton gives somewhat divergent numbers for different numbers of matches in particulars, they're somewhere in between 2^29 and 2^41, but all of them are in the same "close to zero" range. That's for a careful examination, assuming the examiner is not "faulty" in himself (which certainly does not apply to automated systems). I cannot find a reference for the 4% now... you'll have to take my word for that it was in some paper a couple of years ago... :( The Marion Russ murder is a famous example of how wrong things can go with unfalliable evidence. The arrest of Brandon Mayfield in 2004 for the Madrid bombings is another. False rejection and false acceptance rates on automatic matching can be somewhat estimated from data sheets available at biometric lock manufacturers' websites. It has to be said that a forensic computer is somewhat (2-3 orders of magnitude) more accurate under optimal conditions , since it does not have the same time and computational power constraints, but the world is rarely ideal, either. If the input quality varies by 3-4 orders of magnitude, then the output quality obviously does, too. So... again, numbers must be taken with a grain of doubt. But anyway, rough figures. (As far as I'm concerned personally, I would multiply any claimed numbers by a factor of at least 100. Most manufacturers claim FRRs and FARs of <0.1% and <0.001%, respectively, some claim 1/10 of that. I'm seeing a false rejection about twice per day, at <0.1%, that would be 2000 attempts. Not only would that mean that I'd spend a full hour every day with it, but also my finger would be bleeding... this just isn't realistic.) | {
"source": [
"https://skeptics.stackexchange.com/questions/651",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/188/"
]
} |
710 | I recently read a blog that stated: Ash Wednesday is a relatively late addition to the Christian liturgical calendar, first surfacing in the tenth century according to accounts written in the eleventh. On the surface this seems a reasonable fact, and I initially accepted it. However, upon further research and reflection, in the context of the blog, I am having doubts. I am not much of a 10th Century history person, and I was wondering if anyone can verify or debunk this bit of info from that blog. | Properly done, the false positive rate is negligible (estimated under 1:60 billion) assuming that the axiom "fingerprints are individual" is correct in the first place. Using automated matching, the error rates are MUCH higher, especially on partial prints, which the police uses too. Because the false positive rate on those are known to be horrendous, all automated matches are verified manually (though that does not really make it any better). All in all, false positive rates of between 1% and 4% are not uncommon, depending on the investigator's diligence. You should note that identifying a person without doubt is not the intent of matching a fingerprint in the first place, nor is ruling out a possible suspect. A fingerprint match gives the police a "leverage" which may a) be used to justify breaking your civil rights (e.g. arrest, sequestration, body search) and b) gives their case a better "weight" when presented to the district attorney and later to an uncanny judge or jury, and c) press a culprit into confession as he realizes that there is doubtless evidence. Like most forensic "evidence" (such as a DNA sample), fingerprints don't really mean an awful lot, though they are often seen as "unquestionable". For example, your fingerprint on the knife that sticks out of a dead body can equally well mean that you've killed that person or that you've had that knife in your hands in the shop two days ago (you thought about buying one). Your DNA on a cigarette that was found at a crime scene can equally well mean you're the culprit and stupid enough to smoke mid-crime, but it could equally well mean you threw the cigarette on the street the day before, or someone took it out of the ash-tray in your favourite cafe, just to lay a false track against a random person. While it is true that often things indeed are what they look like, they need not be, and sometimes they aren't. However, it is usually assumed that the "evidence" is infalliable, which is an increasing problem in a society where the classic presumption of innocence has turned into "you must prove your innocence". EDIT (some sources were asked for): One source which is freely available online is Galton's somewhat dated book . Don't be put off by the fact that the book is 130 years old. Galton gives somewhat divergent numbers for different numbers of matches in particulars, they're somewhere in between 2^29 and 2^41, but all of them are in the same "close to zero" range. That's for a careful examination, assuming the examiner is not "faulty" in himself (which certainly does not apply to automated systems). I cannot find a reference for the 4% now... you'll have to take my word for that it was in some paper a couple of years ago... :( The Marion Russ murder is a famous example of how wrong things can go with unfalliable evidence. The arrest of Brandon Mayfield in 2004 for the Madrid bombings is another. False rejection and false acceptance rates on automatic matching can be somewhat estimated from data sheets available at biometric lock manufacturers' websites. It has to be said that a forensic computer is somewhat (2-3 orders of magnitude) more accurate under optimal conditions , since it does not have the same time and computational power constraints, but the world is rarely ideal, either. If the input quality varies by 3-4 orders of magnitude, then the output quality obviously does, too. So... again, numbers must be taken with a grain of doubt. But anyway, rough figures. (As far as I'm concerned personally, I would multiply any claimed numbers by a factor of at least 100. Most manufacturers claim FRRs and FARs of <0.1% and <0.001%, respectively, some claim 1/10 of that. I'm seeing a false rejection about twice per day, at <0.1%, that would be 2000 attempts. Not only would that mean that I'd spend a full hour every day with it, but also my finger would be bleeding... this just isn't realistic.) | {
"source": [
"https://skeptics.stackexchange.com/questions/710",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/386/"
]
} |
712 | The official (theirs) description is here Wikipedia here My question is, does this diet lead to substantial weight loss, say a 25% reduction for an obese male, without any serious adverse side affects. By serious, I mean things that would kill you. For instance a statistically significant increased risk of heart attack or cancer is a serious side affect. Also, for the purposes of this question, for a diet to "work" the weight has to stay down and not come back in 12-36 months. | There is evidence that adherents to the Atkins Diet can reduce their weight and keep it off, provided they stick to the diet. One widely cited New England Journal of Medicine study from 2003 looked at 63 participants over one year, and found that Atkins Dieters lost weight faster initially, but slower later on. At one year, there was no significant difference between the weight loss of Atkins Dieters and conventional dieters. The authors noted that "adherence was poor and attrition was high in both groups" and called for longer and larger studies. It is worth noting, as the authors do in their Results section, that the Atkins group saw increases in HDL cholesterol (the good kind) and decreases in triglycerides (low triglyceride count is good) over most of the study. Another study from 2003 in the Journal of Perception and Motor Skills showed that Atkins Dieters "will experience more fatigue, more negative affect, and less positive affect in response to exercise than those individuals who are not restricting carbohydrates." These studies and a small number of other studies are discussed in a 2009 overview of the Atkin's Diet from the American Academy of Family Physicians . They conclude that the Atkins Diet can be effective, and while there are concerns about safety (most notably the risk of long-term heart disease), they assert that the evidence so far is inconclusive on that point. The evidence that the diet is effective should not be taken as evidence that the theories behind the Atkins diet are correct, however. One researcher opined, in a WebMD article that, "No one has shown, in any studies, that anything magical is going on with Atkins other than calorie restriction. The diet is very prescriptive, very restrictive, and limits half of the foods we normally eat. ... In the end it's not fat, it's not protein, it's not carbs, it's calories. You can lose weight on anything that helps you to eat less, but that doesn't mean it's good for you." The high attrition and low adherence mentioned in the first study also tends to support the widely held view that highly restrictive diets, like Atkins and many other diets, are difficult to maintain over the long term. Thus, while they may be effective in the short term at reducing weight, standard lifestyle changes like eating a balanced diet and exercising are likely to be superior for life-long weight loss and health. | {
"source": [
"https://skeptics.stackexchange.com/questions/712",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/34/"
]
} |
765 | A unidentified flying object is just that—a flying object that has not been identified. There need not be evidence of alien hi-jinx. My criteria for a credible UFO report would include: Verified by authentic photographic evidence or several eyewitness reports. Insufficiently explained by natural or human-caused phenomena. Furthermore, such an explanation must not be scientifically suspect, and also must be substantiated. There probably could be a reasonable explanation for all such events, but there must be some underlying evidence that the stated cause was, in fact, in effect at the time. For instance, if it is explained by some human-made aircraft, there must be evidence that such aircraft was flying in the vicinity of the sighting. Of course, as reasoned skeptics, you are free to apply any criteria you deem relevant. | No UFO has ever been revealed to be an alien spacecraft. That said, we can't explain all UFOs through natural phenomena. In some cases the sightings remain mysterious. From 1947 to 1969 a project called "Blue Book" was run by the USAF to investigate UFO sightings. The results are the following: From 1947 to 1969, the Air Force investigated Unidentified Flying
Objects under Project Blue Book. The project, headquartered at
Wright-Patterson Air Force Base, Ohio, was terminated Dec. 17, 1969. Of
a total of 12,618 sightings reported to Project Blue Book, 701 remained
"unidentified." -- source As such, I would say that, yes, unidentified flying phenomena that cannot readily be explained away are quite common, 1 every 11 days on average (in the United States alone). You can now browse the Project Blue Book files online as they have been disclosed. | {
"source": [
"https://skeptics.stackexchange.com/questions/765",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/334/"
]
} |
773 | According to Dr Karl : And in 16th century Naples, in Italy,
kissing was an offence that carried
the death penalty. Is that true? | That exact phrase is repeated numerous times on what appears to be thousands of web sites. However, in the 50 that I took a look at, none of them sourced it. The best I have found is reference to a law passed on March 9th, 1562. Apparently an anti-obscenity law. As to how strictly it was enforced, I again am only getting references to the law itself (without any actual text of the law). Given this pattern, I would suspect that perhaps an anti-obscenity law was passed on that date in Naples, but it was not strictly aimed at kissing, but other behaviour deemed immoral by the local magistrates/clergy/rulers. Kissing was just one thing mentioned. I will continue to search for the original text of this law, but History is not my greatest subject, so I am leaving this as a wiki for the community. | {
"source": [
"https://skeptics.stackexchange.com/questions/773",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/188/"
]
} |
853 | The discovery of several new ant zombie fungi got a lot of media attention over the last two weeks. The fungi take hold over ants and cause them to carry out specific actions beneficial to the propagation of the individual fungus infection. I'm skeptical that a "higher order" animal, meaning a fish or a bird or a mammal, could be "zombified" in such a way that they carry out what amounts to programed, predictable, and sophisticated commands. Has there ever been a case where a substance was introduced into the biology of a higher order animal, causing them to carry out these kind of actions? Doesn't have to be a fungus, even a manufactured and complex "poison" would count, but the outcome has to be a pretty complex action. EDIT: substances that increase suggestibility don't count. After the substance is introduced, the subject needs to carry out the activity without any outside intervention. | Toxoplasma gondii have been reported to make rats less fearful of cats, and may even cause the rats to seek out cat-scented areas. Usually rats would avoid cat-scented areas, but the infection by the parasite can subtly change this behaviour without impacting other behaviours. Changing this behaviour makes a lot of sense for the parasites as cats are its primary host and it can thereby increase its transmission rate. | {
"source": [
"https://skeptics.stackexchange.com/questions/853",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/-1/"
]
} |
875 | According to a very old study plants that “listen” to music have a better growth than other plants. For her next experiment, Mrs. Retallack used two chambers (and fresh plants). She placed radios in each chamber. In one chamber, the radio was tuned to a local rock station, and in the other the radio played a station that featured soothing "middle-of-the-road" music. Only three hours of music was played in each chamber. On the fifth day, she began noticing drastic changes. In the chamber with the soothing music, the plants were growing healthily and their stems were starting to bend towards the radio! In the rock chamber, half the plants had small leaves and had grown gangly, while the others were stunted. After two weeks, the plants in the soothing-music chamber were uniform in size, lush and green, and were leaning between 15 and 20 degrees toward the radio. The plants in the rock chamber had grown extremely tall and were drooping, the blooms had faded and the stems were bending away from the radio. On the sixteenth day, all but a few plants in the rock chamber were in the last stages of dying. In the other chamber, the plants were alive, beautiful, and growing abundantly. This drives my skepticism a lot. Are there more recent studies of this relationship? Can someone have a critical analysis of whether the samples used in the study are or not questionable. Thank you! | The Mythbusters did an experiment on this a while back with results I found amusing: http://mythbustersresults.com/episode23 Seven small greenhouses were set up on the M5 Industries roof. Four were set up with stereos playing endlessly looping recordings (as having the Mythbusters actually talk to the plants could contaminate the samples with their expelled carbon dioxide): Two of negative speech, two of positive speech (Kari and Scottie each made one positive and one negative soundtrack), a fifth with classical music and a sixth with intense death metal music. A seventh greenhouse, used as a control sample, had no stereo. The greenhouses with the recordings of speech grew better than the control, regardless of whether such talk was kind or angry. The plants in the greenhouse with the recording of classical music grew better, while the plants in the greenhouse with the recording of intense death metal grew best of all. Overall, they found it to be plausable. I'm personally unaware of any other studies or experiments done in this area. | {
"source": [
"https://skeptics.stackexchange.com/questions/875",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/71/"
]
} |
907 | There is a lot of clutter from anti-death penalty sites, which makes it hard to find all the research. They often cite statistics like those explained in this website , including the chart below that shows that murder rates in states without the death penalty are lower than those in states with the death penalty. Is a straight comparison of murder rates a fair way to gauge the effectiveness of the death penalty as a deterrent? Might the murder rates be even higher in states that currently have the death penalty if they abandoned the practice? Aren't there likely to be other factors that are contributing to higher murder rates (such as what each state considers to be "murder", or poverty levels, especially in the typically poorer southern states that carry out the majority of executions in the US)? Is there any evidence for death penalty effectiveness that attempts to control for these other variables? What about as a deterrent for other crimes besides murder? Unless you're on here from China or Iran, I imagine this is a pretty uniquely US question. However, many European countries currently without the death penalty once had such laws, and perhaps the arguments used in those older debates would have merit. UPDATE: I think ideally the answer to this question should involve some crime statistics from a place that had the death penalty, and then abolished it, or vice versa. Ideally modeled in a way to try and control for other factors (as much as possible). | tl;dr: There is no evidence supporting the conclusion that capital punishment is an effective deterrent for murder, and significant evidence to the contrary. The only way to arrive at an alternative conclusion would be to ignore or refute: the results of multiple surveys done by the United Nations; a systematic review and rebuttal of all significant papers that ostensibly demonstrated statistically significant deterrence from capital punishment, by a Professor of Mathematics at Dartmouth College; a systematic review and rebuttal of all significant papers that ostensibly demonstrated statistically significant deterrence from capital punishment, by a Professor of Law & Public Health at Columbia University; the uncontroverted opinion of Justice Marshall of the Supreme Court of the United States who reviewed a "massive amount of evidence"; the opinion of an overwhelming majority of leading criminologists in the USA; and the statistics in Canada that show a highly significant and consistent decrease in murder since the abolishment of capital punishment in 1976 (i.e. from a murder rate of 3.09 per 100,000 people in 1975, to 1.77 per 100,000 in 2009). Amnesty International Amnesty International, an organization with an incentive to corral information on this topic, provides an article, citing statistics from the United Nations, entitled “ THE DEATH PENALTY, QUESTIONS AND ANSWERS ” which states (with my emphasis): What do you say to the argument that the death penalty is an important tool for a state to fight crime? Too many governments believe that they can solve urgent social or political problems by executing a few or even hundreds of their prisoners. Too many citizens in too many countries are still unaware that the death penalty offers society not further protection but further brutalization. Scientific studies have consistently failed to find convincing evidence that the death penalty deters crime more effectively than other punishments. The most recent survey of research findings on the relation between the death penalty and homicide rates, conducted for the United Nations in 1988 and updated in 1996 and 2002, concluded: "...research has failed to provide scientific proof that executions have a greater deterrent effect than life imprisonment. Such proof is unlikely to be forthcoming. The evidence as a whole still gives no positive support to the deterrent hypothesis". Recent crime figures from abolitionist countries fail to show that abolition has harmful effects. In Canada, for example, the homicide rate per 100,000 population fell from a peak of 3.09 in 1975, the year before the abolition of the death penalty for murder, to 2.41 in 1980, and since then it has declined further. In 2003, 27 years after abolition, the homicide rate was 1.73 per 100,000 population, 44 per cent lower than in 1975 and the lowest rate in three decades. Although this increased to 2.0 in 2005, it remains over one-third lower than when the death penalty was abolished. It is incorrect to assume that people who commit such serious crimes as murder do so after rationally calculating the consequences. Often murders are committed in moments when emotion overcomes reason or under the influence of drugs or alcohol. Some people who commit violent crime are highly unstable or mentally ill. Amnesty International has found that at least one in 10 of the prisoners put to death in the USA since 1977 had suffered from serious mental disorders rendering them unable to rationally comprehend their death sentence, its reasons or its implications.In none of these cases can the fear of the death penalty be expected to deter. Moreover, those who do commit premeditated serious crimes may decide to proceed despite the risks in the belief that they will not be caught. The key to deterrence in such cases is to increase the likelihood of detection, arrest and conviction. The fact that no clear evidence exists to show that the death penalty has a unique deterrent effect points to the futility and danger of relying on the deterrence hypothesis as a basis for public policy on the death penalty. The death penalty is a harsh punishment, but it is not harsh on crime. and, as capital punishment relates to terrorism and political violence: Isn't the death penalty needed to stop acts of terrorism and political violence? Officials responsible for fighting terrorism and political crimes have repeatedly pointed out that executions are as likely to increase such acts as they are to stop them. Executions can create martyrs whose memory becomes a rallying point for their organizations. For men and women prepared to sacrifice their lives for their beliefs -- for example suicide bombers -- the prospect of execution is unlikely to deter and may even act as an incentive . State use of the death penalty has also been used by armed opposition groups as a justification for reprisals, thereby continuing the cycle of violence. As an organization that seeks to protect human rights and is philanthropically funded as such, Amnesty International has a perceived bias towards this conclusion. However, I would expect that any persuasive research to the contrary – i.e. that homicide rates decline in areas with capital punishment – would be referenced, by AI as a matter of protocol and integrity. I have seen no such references, by AI or otherwise. Statistics since Canada abolished capital punishment The Canadian statistics referred to in the above can be found in a report by Amnesty International entitled “ The Death Penalty in Canada: Twenty Years of Abolition ”, which provides: Contrary to predictions by death penalty supporters, the homicide rate in Canada did not increase after abolition in 1976. In fact, the Canadian murder rate declined slightly the following year (from 2.8 per 100,000 to 2.7). Over the next 20 years the homicide rate fluctuated (between 2.2 and 2.8 per 100,000), but the general trend was clearly downwards. It reached a 30-year low in 1995 (1.98) -- the fourth consecutive year-to-year decrease and a full one-third lower than in the year before abolition. In 1998, the homicide rate dipped below 1.9 per 100,000, the lowest rate since the 1960s. Although the research in Canada only shows a correlation (i.e. not a causation), it does provide the specific statistics on a jurisdiction that abolished capital punishment – which was posed as part of this question. It is noteworthy that while Canada has uniform criminal laws across the country, its social policies are diverse as between its provinces, and yet the abolition of capital punishment lowered murder rates across the country. Professor Lamperti, professor of Mathematics at Dartmouth College Here is another reference, from John Lamperti, a professor of mathematics at Darthmouth College, entitled “Does Capital Punishment Deter Murder? A brief look at the evidence” , which seems to review most of the knowledge on the topic in the United States, and concludes: Those who defend the deterrent value of the death penalty offer little
systematic research to support their view. Instead, they rely on an intuitive
feeling that capital punishment should be uniquely effective. When the
available evidence doesn't support that conclusion, they argue that the
evidence is imperfect. It is. But if there were any substantial net deterrent
effect from capital punishment under modern U.S. conditions, the studies we
have surveyed should clearly reveal it. They do not. Professor Fagan, professor of Law & Public Health at Columbia University The view of Professor Lamperti is affirmed by the systematic review of Jeffrey A. Fagan, Professor of Law & Public Health at Columbia University in his article “ Capital Punishment: Deterrent Effects & Capital Costs ”. In this article, Professor Fagan provides a thorough and highly critical analysis of the flaws in the statistical methods and conclusions of those who argue capital punishment is an effective deterrent: When we apply contemporary social science standards, the new deterrence studies fall well short of this high scientific bar. Most of the studies fail to account for incarceration rates or life sentences, factors that may drive down crime rates via deterrence or incapacitation; one study that does so finds no effects of execution and a significant effect of prison conditions on crime rates. Another report shows incarceration effects that dwarf the deterrent effects of execution. Most fail to account for complex social factors such as drug epidemics that are reliable predictors of fluctuations in the murder rate over time. ... The computations in the statistical models are often flawed. For example, simple corrections for large amounts of missing data produce estimates of the deterrent effect of execution that are no different from chance. Using alternate statistical models - models that account for the strong statistical correlation of murder rates from one year to the next - also produces results that show that changes in homicide rates are statistically unrelated to any measure of capital punishment. Professor Fagan also notes that the rarity of capital punishment limits the effectiveness of its deterrence – it is applied so infrequently that it is incoherent to believe it would enter into the state of mind of potential murderers. Professor Fagan goes on to comment that no study has ever been put forward that provides any evidence whatsoever that capital punishment ever enters into the state of mind of those who are about to commit murder (i.e. none of the studies even address causation): ... There is no evidence that if aware of the possibility of execution, a potential murderer would rationally decide to forego homicide and use less lethal forms of violence. Murder is a complex and multiply determined phenomenon, with cyclical patterns for distinct periods of more than 40 years of increase and decline that are not unlike epidemics of contagious diseases. There is nothing in the new deterrence studies that fits their story into this complex causal framework. Furman v Georgia, 1972 (SCOTUS), opinion of Justice Marshall Much discussion of this topic in the USA goes back to a decision, Furman v. Georgia, 1972, of the Supreme Court of the United States. Professor Lamperti's paper opens with a quote from a decision of Justice Marshall, a Judge on that decision: In light of the massive amount of evidence before us, I see no alternative
but to conclude that capital punishment cannot be justified on the basis of its
deterrent effect. — Justice Marshall, U.S. Supreme Court, Furman v. Georgia , 1972 Professor Lamperti's paper contrasts the quote of Justice Marshall with the views of President Richard Nixon, who expressed the opinion that “the death penalty can be an effective deterrent of specific crimes”. It is worthwhile to note that Justice Marshall's conclusion was uncontroverted. No Judge concluded that capital punishment was justifiable on the basis that there was evidence of it being effective. Rather, the other position taken before the Court seemed to be that prohibiting states from employing capital punishment was a jurisdictional issue i.e. the power to prohibit capital punishment was outside the scope of the powers of the US federal government. As I read it, none of the Judges of the Supreme Court stated that there was any evidence before the Court that capital punishment was effective. Almost all Criminologists Professor Lamperti notes that his view is consistently affirmed by leading criminologists: Marshall's view is today supported by an overwhelming majority among America's leading
criminologists, who believe that capital punishment does not contribute to
lower rates of homicide [footnote: Michael Radelet and Ronald Akers, "Deterrence and the death penalty: the views of the experts," Journal of Criminal Law & Criminology 87, no.1 (1996), pp. 1-16.] The above is affirmed in the more recent article “Do Executions Lower Homicide Rates? The Views of Leading Criminologists,” Journal of Criminal Law and Criminology 99 (2009): 489-508 (Michael L. Radelet and Traci L. Lacock). Few are as eminent in criminology as Professor Radelet , from whom I select a choice quote “The more people know about the death penalty the more likely they are to oppose it” . The United Nations, Norval Morris and Marc Ancel Criminologist Norval Morris prepared for the United Nations (and, incidentally, cited by Justice Marshall in the Furman case), citation Capital Punishment, UN Doc. ST/SOA/SD/9 UN Doc. ST/SOA/SD/10 (1968), Vol. II, p.123 states: It is generally agreed between the retentionists and abolitionists, whatever their opinions about the validity of comparative studies of deterrence, that the data which now exist show no correlation between the existence of capital punishment the lower rates of capital crime. This was one of several reports prepared for the United Nations from 1959-1980. See e.g. The Abolition of the Death Penalty in International Law, By William A. Schabas at pp.156ff. One notable report was by the eminent French jurist Marc Ancel, who concluded "all the information available appears to confirm that such a removal [of the death penalty] has, in fact, never been followed by a notable rise in the incidence of the crime no longer punishable with death ." It is worth noting that when these studies began in the 1950's the majority of UN state members were "retentionist" (i.e. they retained capital punishment, as opposed to abolitionist). In 1977, only 16 or so countries were considered abolitionist (not having a penalty of death), whereas by 2012 that number was around 97 . In other words, the studies were commissioned and paid for by the United Nations at a time when the organization was predominantly composed of states that employed capital punishment. Conclusion State-sponsored killing of people in the name of capital punishment is ostensibly justified because it prevents further crimes. This deterrence falls into two categories, specific deterrence (i.e. recidivism by the convicted) and general deterrence (i.e. dissuasion of potential murderers other than the convicted). As a specific deterrent capital punishment has no known benefits over life imprisonment. As a general deterrent, there has never been a study indicating that the state of mind of any murderer has ever been influenced by the possibility of capital punishment. Further, no jurisdiction has ever been mentioned for having a decrease in crime rates because it implemented capital punishment. A persuasive counter-argument by an advocate of capital punishment ought to explain the dramatic drop in murder rates after Canada abolished it, the opinion of the majority of US criminologists and Justice Marshall, and the comprehensive academic and UN reports indicating an absence of deterrence from capital punishment. No such counter-argument has been forthcoming. Which is all to say that capital punishment is not known to be an effective deterrent for murder. Please permit one final quote from Professor Lamperti: If executions protected innocent lives through deterrence, that would weigh
in the balance against capital punishment's heavy social costs. But despite
years of trying, this benefit has not been shown to exist; the only proven
effects of capital punishment are its liabilities. | {
"source": [
"https://skeptics.stackexchange.com/questions/907",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/-1/"
]
} |
908 | Many articles, such as this one , report a significant wage gap between men and women of 15% or more as evidence of discrimination. On the other hand, some sources, such as this one , claim that the gap can be explained by factors such as the following: Men being more career obsessed Men working more hours Differences in experience Is there a significant difference in wages between men and women in first world countries that is not due to factors relevant to the job? | I can only give an example for developed countries. In the Ny Times article Why the Earnings Gender Gap in Business? Women Work Less from 2009 they cite research on MBA couples, and it's argued that wages remain largely the same among MBA holders up until the first child. After which most mothers (who continue their careers) are affected more than fathers when trying to balance motherhood and work. Similarly in We did it! - The rich world’s quiet revolution: women are gradually taking over the workplace from the Economist also from 2009 argues that women who do well in their careers in their 20's, disappear in their 30's because they have to choose between motherhood and the career. In the same issue of the Economist they give the statistics in the article Female power - Across the rich world more women are working than ever before. Coping with this change will be one of the great challenges of the coming decades : Another American study, this time of
women who left work to have children,
found that all but 7% of them wanted
to return to work. Only 74% managed to
return, and just 40% returned to
full-time jobs. There are other differences between men and women in modern times that should create a shift in wages. In Sweden (my home country) 60% of university students are women according to the national university review of 2008 (in Swedish, sorry), and women typically do better than men in school {citation needed?}. I would argue that if university graduates earn more than non-graduates in the same job then womens wages will progress to the point where they overtake men if the above mentioned issue isn't a factor. Some support that things have changed for women since 1970 was recently shown in Marginal revolution (a blog by two well published economists) where they plotted GDP in America together with the median wage by gender. They showed that while womens wages closely follow GDP, males wages have stagnated. If true this would mean that women are closing the income gap on males at the rate that the GDP changes. More recently in 2015 a German newspaper reported on a German study that women work 23% fewer hours than men, with a wage gap of 22%. The work week difference of 7 hours doubles to a difference of 15 hours once there's children. It also says that of women with children 70% work part-time twice the amount of those without. Interestingly for men in Germany the change happens in the other direction where 6% of men with children work part-time, as opposed to 10% of those without. My German isn't good enough to read the original study for the researchers thoughts, but it seems to suggest that the wage gap in Germany is explained by the number of hours worked as opposed to wage discrimination. I don't have a better answer than this, but I hope I've added a some food for others. TL;DR Women start earning less when they
get children because they value
parenting more. If we are merely concerned with women as a whole demographic being underpaid then I would expect that they are going to rise above men as a whole demographic as we are graduating women in larger numbers and with better grades, which is a fairly recent happening. | {
"source": [
"https://skeptics.stackexchange.com/questions/908",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/188/"
]
} |
944 | Was it common practice for pirates to replace a lost hand with a prosthetic hook? Or was this lore perpetrated by fiction and Hollywood? It does seem like a reasonable choice, since a hook is a rather cheap and simple to make prosthesis. But is there historical evidence that shows that a hook was the go-to prosthesis for pirates? Or did their job actually require a more sophisticated prosthesis? | Apparently it's true: From "How Stuff Works" Most famously attributed to seafaring pirates, peglegs with wooden cores and metal hands shaped into hooks have actually been the prosthetic standard throughout much of history. While Hollywood has exaggerated their use of hooks and peglegs, pirates did sometimes rely on these types of prostheses. The required materials for these devices could be scavenged from a common pirate ship; however, a trained doctor would have been rare. Instead, the ship's cook typically performed amputation surgeries, albeit with poor success rates. | {
"source": [
"https://skeptics.stackexchange.com/questions/944",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/454/"
]
} |
956 | I've heard this repeatedly over the years, that Einstein was bad at math, that he was bad at history, that he was dyslexic. I also read somewhere in my youth that some of the " bad at math" stuff was based on a poor exam score he once received - but that the test had been in French, which Einstein couldn't read. Can someone cut through the junk and get to the heart of this. Was one of history's greatest "teachers" a bad student, or have a learning disability? I find it hard to believe. | No, he wasn't: page with german article and image of school certificate The Swiss school system has a 6 as best grade, and 1 as poorest, while the german is the other way round. Perhaps the legend is founded there. -- source Translation of the subjects and grades in the image: The education council of the Canton Aargau
certifies Albert Einstein, born Mar. 14 1879
final secondary-school examinations from Sep 18, 19, 21 and 30
German language and literature : 5
French " " " : 3
English " " " : -
Italian " " " : 5
History : 6
Geography : 4
Algebra : 6
Geometry : 6
Descriptive geometry : 6
Physics : 6
Chemistry : 5
Natural history : 5
Artistic drawing : 4
Technical drawing : 4
documented at 3rd of Oct., 1896 | {
"source": [
"https://skeptics.stackexchange.com/questions/956",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/-1/"
]
} |
976 | I have seen numerous arguments about gun control, in the sense of laws restricting gun ownership or possession, and whether widespread gun possession affects crime rates, and each side is happy to pull out studies that are favorable to their side. I really haven't felt I could trust any of them. I hope this isn't too much of a hot potato, but are there any serious scientific studies available? Or at least reasonably unbiased? | I don’t know how well a single case-study can be generalised, or applied in a different cultural setting. But since jozzas’ answer on the Australian gun control act exclusively relies on a paper that completely misrepresents the evidence here’s another stab at it: Background In 1996, after a mass shooting with an illegally purchased but legally available semi-automatic weapon in Port Arthur, Tasmania that killed 35 people and wounded 23, Australia enacted the National Firearms Agreement (NFA), a strict ban on semi-automatic weapons and stricter requirements for acquiring a weapon permit. They also enacted a compulsory gun buyback scheme taking effect immediately which resulted in 600,000 guns being bought back from the state, at a cost of 500 million AUS$ . The government levied a 1% addition in income tax for one year to finance this. Data & evidence The following gives a broad overview over a huge mass of data. I tried my hardest to represent the data fairly; however, by necessity I leave out quite a lot (otherwise I’d have to publish a paper). Most of the missing data and justifications can be found in Leigh & Neill [2] which gives a truly excellent run-down of the evidence, along with a careful explanation and justification of the statistical methods used, and a comprehensive explanation of the limitations of the data . In fact, this latter point makes the paper stand out particularly. Massacres. In the 18 years prior to the enactment of the NFA, there had been 13 massacres in Australia involving guns (defined as killing ≥ 4 people). In the years since, there have been none . However, while such large-scale killings are obviously tragic events they contribute relatively little to the overall rates of deaths by guns. Murder rate. Australia has generally had low levels of violent crime even before the ban. Furthermore, there’s been a steady decline in the number of firearm-related deaths since the early 1980s [1, 2], in particular, there was a 47% decrease between 1991 and 2000. This was accompanied by a similar decrease in non-firearm related murders. On the other hand, there was a clear acceleration of the reduction after the NFA was enacted, but [2] found that this reduction falls short of statistical significance. Suicide rate. What they managed to show, though, was that the NFA buyback contributed strongly and significantly to a reduction in suicides. To ensure that they weren’t just looking at a reduction over time which started before the NFA, they compared across states and correlated reduction with number of guns bought back by the state, and find that more gun buyback by the state results in more reduction in suicide with a statistically significant trend ( R 2 = 0.7685, p -value = 0.004% – this is a very robust statistic that cannot be explained away by any other factors that the authors examined). The gun buyback led to a reduction by 1.9 per 100,000 for each 3.500 withdrawn guns per 100.000 individuals (95% CI), which is a 74% reduction. This state-dependent trend and its correlation is shown here: Compensation. Both murder and suicide rates declined globally , that is, reductions in gun death weren’t increased by use of other weapons. However, in the first few years after the NFA, non-gun suicides were briefly raised, continuing a prior trend, before dropping as well. No such trend exists for homicides. Cost. The gun buyback cost 500 million AUS$. On the other hand, [2] estimates that the 200 annual deaths thus prevented correspond to an economic saving of 500 million AUS$ per year . This would correspond to a 7 billion AUS$ cost saving. Could this money have spent differently to get a similar (or better) reduction in gun-related deaths? I couldn’t find any data analysing this. However, the buyback was essentially a one-off cost so amortised over time no ongoing intervention could have a better cost-benefit relation. Significance As mentioned, the robust data analysis shows a marked reduction in suicide rates. [2] goes into more detail to improve the robustness of the analysis by doing subsampling and trying (unsuccessfully) to explain the reduction with other variables. Lee & Suardi [3] have argued that no such reduction exists for homicide rates because the time series data doesn’t show a “structural break”. That may be so ([2] didn’t find a statistically significant reduction for homicide rates either). However, [2] notes that such structural breaks cannot be assumed to exist due to the large number of factors influencing death rates. Baker & McPhedran [4] claim that even the suicide rate reduction is not related to the NFA buyback. However, [2] notes that this paper is deeply flawed since it wouldn’t infer significance even if homicide rates had been negative in the years after 2004, and that the authors of [4] “should know better”. Overall , the NFA and buyback were correlated with a significant reduction in firearms related deaths, and no balancing increase in non-firearms related deaths. Putting things into perspective Is this evidence convincing? Yes: It is the best evidence we have, and while statistically flawed methods find no effect, correcting statistical mistakes invariably finds a significant reduction. And in fact, it is the best evidence we could hope for , because it is the kind of signal we would expect to get if we knew that there were a real effect: no sharp break but a steady decline. In fact, in the words of the authors of [2], from the perspective of 1996, it would have been difficult to imagine more compelling future evidence of a beneficial effect of the law. Notable references [1] Jenny Mouzos & Catherine Rushforth, “Firearm related deaths in Australia, 1991–2001” , Trends and issues in crime and criminal justice, no. 269 , Nov 2003 [2] Andrew Leigh & Christine Neill, “Do Gun Buybacks Save Lives? Evidence from Panel Data” , American Law and Economics Review, Vol 12 (2) pp 462–508, Aug 2010 [ PDF ] [3] Wang-Sheng Lee & Sandy Suardi, “The Australian Firearms Buyback and Its Effect on Gun Deaths” , Contemporary Economic Policy, Vol 28 (1) pp 65–79, Jan 2010 [ PDF ] [4] Jeanine Baker & Samara McPhedran, “Gun Law and Sudden Death – Did the Australian Firearms Legislation of 1995 Make a Difference?” , British Journal of Criminology, Vol 47 (3), 2007 [ PDF ] | {
"source": [
"https://skeptics.stackexchange.com/questions/976",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/39/"
]
} |
999 | Cutting sleep down to 6, or 4, or 2 hours per day sounds fantastic. It also sounds like something that should have evolved naturally if it were possible. From the Polyphasic Society : Humans are naturally polyphasic sleepers. Depending on the culture, humans will either have segmented night sleep, or nap throughout the day. The reason humans sleep polyphasically is to improve sleep density, sleep stability, and for the warriors out there decrease overall time asleep. Humans need sleep, but only certain stages of sleep are important for us to recover each night. Has any serious research been done into polyphasic sleep and its side effects? Polyphasic sleep involves sleeping more than once per day at regular intervals and for regular amounts of time. There are different specific regiments, but the overall goal is usually to reduce the total time spent sleeping. | There is little research published in scientific journals about conscious adoption of extreme sleep patterns. In 2000 PureDoxyk proposed the Uberman schedule:
Every four hours you sleep 20 minutes. It takes a lot of willpower to adopt a sleep pattern like Uberman that only allows 2 hours of sleep per day. People need a deep inner desire to adopt such a schedule or there will be no compliance with the experimental setup. Most people who try to adopt the Uberman schedule fail very soon. There are some such as Steve Pavlina or Tynan claim to have followed the schedule and produced a detailed account of the experience at their website.
Steve Pavlina quit the schedule after 5 1/2 months.
Tynan quit after 4 1/2 months.
PureDoxyk quit after 6 months.
They all cite impracticality of having to sleep every 4 hours as reason for quiting. There's a Time article from 1943 that reports Buckminster Fuller to have spent two years on a polyphasic sleep shedule with two hours per day he called dymaxion sleep. To my awareness there's no contemporary person who upheld the schedule for multiple years. Even if it's possible to keep up with the Uberman schedule it doesn't seem to worthwhile or those people would probably have continued with it. As far as short term side effects goes there seems to be mental effects. We unfortunately don't have much more than self reporting about most of the polyphasic sleepers. I will therefore write a bit which is my own understanding from reading about polyphasic sleep. A lot of polyphasic sleepers report to be more productive during the time they are on the schedule. Polyphasic sleep forces you to do detailed time management or you screw up. The forced time management might account for the gain in productivity. It's my understanding that the mental state is similar to the state of calmness, that's reached through doing a lot of meditation. The sleepers might therefore perform better on some tasks. On the other hand long deep problem solving such as making mathematical proofs might suffer. In a lot of the polyphasic sleep writing you find the claim that those who practice the Uberman schedule are in the REM state when they sleep. It's my understanding that Claudio Stampi showed in Why We Nap: Evolution, Chronobiology, and Functions of Polyphasic and Ultrashort Sleep that this isn't what happens when people adapt to short nap based sleep. What about sleeping 6 hours? There was a huge study that concluded that people who sleep 6 hours have a longer life span than those that sleep 8 hours.
Correlation isn't causation and this doesn't mean that you will be healthier when you cut your sleep to 6 hours. It however makes it plausible that a 6 hour sleep schedule could be healthy. If you want to understand more about polyphasic sleep cycles there's a mailing list and a forum .
The forum is run by the Zeo guys who produce equipment to measure sleep states. With a bit of luck they will be able to gather enough data in the coming years to publish a bit on polyphasic sleep schedules. it also sounds like something that should have evolved naturally if it were possible. The ability to stay awake for 12 hours without pause is quite valuable. People who practice the Uberman schedule lose the ability.
If you are a hunter gatherer you don't profit very much from being awake at night. It's harder to protect yourself when you don't stay near the fire that your tribe lighted during the night.
I would note that the sleep practices of a person in the western world who sleep in a bed without a nearby fire are very different from the sleep practices according to which we developed. | {
"source": [
"https://skeptics.stackexchange.com/questions/999",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/753/"
]
} |
1,018 | As a response to the disaster at the Fukushima nuclear power plant I've heard the claim that fossil-fuel power plants using coal release more radiation than a nuclear power plant. I searched for some information and found an article supporting this statement in the Scientific American called Coal Ash Is More Radioactive than Nuclear Waste . This is a topic with huge political and economic interests which makes accurate and reliable information hard to find. I'm now wondering if that comparison of coal ash and nuclear waste is accurate, and also if it is misleading, how it compares to the real-world radiation release. How much radiation is released by coal and nuclear power plants in regular operation? How do the numbers compare if you include different types of nuclear accidents? | The answer to your first question is already in the article you linked. It contains the following referenced quote: In fact, the fly ash emitted by a power plant—a by-product from burning coal for electricity—carries into the surrounding environment 100 times more radiation than a nuclear power plant producing the same amount of energy. The paper referenced in the article is here: http://www.sciencemag.org/content/202/4372/1045.short Radiation doses from airborne effluents of model coal-fired and nuclear power plants (1000 megawatts electric) are compared. Assuming a 1 percent ash release to the atmosphere (Environmental Protection Agency regulation) and 1 part per million of uranium and 2 parts per million of thorium in the coal (approximately the U.S. average), population doses from the coal plant are typically higher than those from pressurized-water or boiling-water reactors that meet government regulations. Higher radionuclide contents and ash releases are common and would result in increased doses from the coal plant. The paper itself states that this result is only valid not considering nuclear accidents and nuclear waste, nor it considers non-radiological effects: The study does not assess the impact of non-radiological pollutants or the total radiological impacts of a coal versus a nuclear economy. Regarding your second question, it can be answered easily: The paper itself speaks about Uranium and Thorium being released by normal operation in less than 10 parts per million - very very low doses A bad nuclear accident leaves kilograms or tons of radioactive elements exposed or emitted Typically nuclear waste is composed of tons of material So it is clear that a single nuclear accident widely offsets any "gains" obtained by using a nuclear plant instead of a coal plant. Furthermore, the average radiation we all get by "living" makes the normal power plant emissions irrelevant: Living within 50 miles (~80 km) of a nuclear reactor (1 year): 0.09 µS; Living within 50 miles (~80 km) of a coal plant (1 year): 0.3 µS; Daily average radiation: 10 µS; Living in within 30 km of Chernobyl before evacuation (10 days): 3-150 mS The first three are data from the image below, the third comes from from Reconstruction of the inhalation dose in the 30-km zone after the Chernobyl accident Thanks to Borror0 for the great find. To put things in perspective see the following infograph . At the top left, in blue, you can see the radiations absorbed by living next to a (nuclear|coal) plant. In yellow, the radiation doses of Chernobyl - many orders of magnitude higher. | {
"source": [
"https://skeptics.stackexchange.com/questions/1018",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
1,039 | I have seen the stats on this website saying that the number of death caused by nuclear accidents was way smaller then those caused by any other energy production factory. Do you have any information, studies that can confirm that? And numbers for accidents caused by windmills? Thanks! | An update, as I found some interesting information: This post has deaths per Terawatt hour for various energy sources: Energy Source Death Rate (deaths per TWh) OLD Coal – world average 161 (26% of world energy, 50% of electricity) Coal – China 278 Coal – USA 15 Oil 36 (36% of world energy) Natural Gas 4 (21% of world energy) Biofuel/Biomass 12 Peat 12 Solar (rooftop) 0.44 (less than 0.1% of world energy) Wind 0.15 (less than 1% of world energy) Hydro 0.10 (europe death rate, 2.2% of world energy) Hydro - world including Banqiao) 1.4 (about 2500 TWh/yr and 171,000 Banqiao dead) Nuclear 0.04 (5.9% of world energy) Even solar power is 0.44 deaths per TWh (I'm thinking installers falling off the roof:-) | {
"source": [
"https://skeptics.stackexchange.com/questions/1039",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/800/"
]
} |
1,052 | A little context on this famous myth: The Shroud of Turin or Turin Shroud is a linen cloth bearing the image of a man who appears to have suffered physical trauma in a manner consistent with crucifixion. Some contend that the shroud is the actual cloth placed on the body of Jesus Christ at the time of his burial, and that the face image is the Holy Face of Jesus, while others contend that the artefact was created in the Middle Ages, as indicated by carbon dating which placed the artifact between 1260 and 1390. Now, the JREF claims that this particular myth is absolutely debunked. I completely agree that the shroud has not, and will never, be proven to be a genuine holy item - how could one prove that it was used on Jesus of Nazareth at all? On the other hand, the way the myth is debunked is, in my view, flaky, weak and unconvincing. Here in short are the claims, after each my doubts: The cloth itself could not date from the correct period or from that area of the world, simply because that particular weave of cloth was not made then or there. I cannot find any good source to verify this. In any case I don't see how we can easily make such assertion (it could be an uncommon type with few examples left). Wrapping of a body in that size and shape of cloth was not done in Palestine at that period. Such wrapping disagrees with the biblical description as well. This is completely irrelevant - either the cloth is from that place and time or it isn't. It could have been an unusual choice. The representation of the face of Christ on this cloth and in all paintings and sculptures is and always has been a formalized guess. This version matches the “accepted” one. We know nothing about Christ's actual appearance. This is also totally irrelevant - the fact that Jesus has been depicted as a hippy guy with a beard does not rule out or confirm anything about his appearance (if he existed). Carbon dating of the fabric, done in three independent labs, showed that the linen fabric was woven about the year 1350. True, but there are claims that the results might have been obtained by medieval repairs instead that from an original part of the cloth. The areas that have been cut off were the worst kept in order not to destroy important parts of the cloth. The “bloodstains” are not only red in color (they could not be, after that period of time), but they were shown by chemical analysis to be paint of the composition used in the fourteenth century. I cannot find any real affirmative confirmation of this claim - I can only find claims that someone made paint of the same color as the shroud, but no confirmation that "chemical analysis" has been performed on the shroud at all. Wikipedia, for what is worth, has a totally different story on the matter. The bishop of Troyes (Lirey) knew who the artist was who painted the cloth and when and how he did it, and so reported to Pope Clement VII. The document still exists and has been shown to be unquestionably authentic. This is shaky evidence - it's hearsay. The question is the following: is the JREF correct when they affirm that Definitive tests prove absolutely that it is a forgery ? | Remember the burden of proof in this case is on the believer to prove that the shroud is genuine, not for the skeptic to prove it a forgery. The definitive testing of the shroud was done in 1988 by 3 independent laboratories (and possibly verified by a fourth) in Zurich, Oxford and the University of Arizona. You can find the results of the radiocarbon dating done by accelerated mass spectrometry here . The methods for the taking of samples and the treating of results were agreed upon by the three labs, overseen by the British Museum, and approved by the Archbishop of Turin and the Holy See (owner of the shroud). All showed cloth dating from the 1300's. The findings of these results confirm those done by McCrone, who examined the shroud using electron microscopy in the late 70's and identified the pigment of the shroud as red ochre. His published results are here . There have been attempts to claim that biological or other contaminants caused a false reading. Those claims are thoroughly refuted here by demonstrating that the 9kg shroud would have to be covered in 40kg of biological contaminants for the reading to be skewed enough for the shroud to be from around 36 C.E. There have been some claims that the sample was contaminated by fire damage, or water damage (or both, depending on who you read), and there have also been claims that there are "unauthorized, undocumented" repairs through history which resulted in contamination. here is one such claim, I find it to be particularly weak in light of the above evidence. This information, should be considered with what is known historically about Geffroy de Charny (possible spelling error there, sorry!) who showed up sometime in the 1350's with the shroud and a desire to build a church (which in those days needed a really cool relic to be a really cool church). So, there is no definitive historical proof of a named and documented individual who can be proven to have lived in the time period providing evidence showing that he, himself was the creator of the shroud. However, the evidence that is available points to a quite rational, simple explanation. The simple fact is that based on the demonstrable evidence at this time, the shroud does not meet the burden of proof to be considered legitimate. If you are interested, you can find a list of theories, experiments, hypotheses and studies done over the years by various organizations with various agendas conducted with various degrees of scientific rigor here . | {
"source": [
"https://skeptics.stackexchange.com/questions/1052",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/96/"
]
} |
1,059 | It's widely believed that consuming small amounts of alcohol has many health benefits. As a matter of fact, a lot of alcohol might be good for you, as Wired Magazine reports : It’s one of those medical anomalies that nobody can really explain: Longitudinal studies have consistently shown that people who don’t consume any alcohol at all tend to die before people who do. Well, the anomaly has just gotten more anomalous: A new study , published in the journal Alcoholism: Clinical and Experimental Research, followed 1,824 participants between the ages of 55 and 65. Once again, the researchers found that abstaining from alcohol increases the risk of dying, even when you exclude former alcoholics who have now quit. (The thinking is that ex-drinkers might distort the data, since they’ve already pickled their organs.) While 69 percent of the abstainers died during the 20-year time span of the study, only 41 percent of moderate drinkers passed away. (Moderate drinkers were also 23 percent less likely to die than light drinkers.) But here’s the really weird data point: Heavy drinkers also live longer than abstainers. (Only 61 percent of heavy drinkers died during the study.) In other words, consuming disturbingly large amounts of alcohol seems to be better than drinking none at all. Is this true? Is there any conflicting evidence? If it is true, is there any indication as to what it does that might cause these beneficial effects? | The study is from a reputable scientific journal, and appears to apply good scientific methods and to exclude (as far as possible) a large number of alternative factors that might have caused the difference in mortality. Also this is far from the only study to have found that moderate alcohol consumption correlates with better health and longer life. Most studies report probable health benefits, but stop short of stating a provable connection. Here is a report which lists five scholarly scientific studies showing the correlation. Here is a Mayo Clinic study. Moderate alcohol consumption may provide some health benefits. It may: Reduce your risk of developing heart disease; Reduce your risk of dying of a heart attack; Possibly reduce your risk of strokes, particularly ischemic strokes; Lower your risk of gallstones; Possibly reduce your risk of diabetes. Even so, the evidence about the possible health benefits of alcohol isn't certain, and alcohol may not benefit everyone who drinks. Here is one from the National Institute on Alcohol Abuse and Alcoholism (which also lists some of the downsides). In the past two decades, however,
a growing number of epidemiologic
studies have documented an association
between alcohol consumption and
lower risk for coronary heart disease
(CHD), the leading cause of death in
many developed countries (Chadwick
and Goode 1998; Criqui 1996a,b;
Zakhari 1997). Much remains to be
learned about this association, the
extent to which it is due specifically to
alcohol and not to other associated
lifestyle factors, and what the biological
mechanisms of such an effect might be Here is the US dietary guidelines, alcohol section. Heavy drinking
increases the risk of liver cirrhosis, hypertension, cancers of the upper gastrointestinal tract, injury,
and violence (USDA, 2000). A recent analysis of the preventable causes of mortality in the United
States (US) attributed 90,000 deaths a year to alcohol misuse (Danaei, 2009). However, the health
consequences of consuming lesser amounts of alcohol are also important because of the large
percent of the population that consumes alcohol at or below government recommendations on
limits for intake. It is estimated that 26,000 fewer deaths were averted due to reductions in heart
disease, stroke and diabetes from the benefits attributed to moderate alcohol consumption. Drinking moderate amounts of alcohol will impair your judgement, possibly causing you to drink more alcohol than you intended. The risks of alcoholism and vehicle accident are well known - I guess they could be considered counter-evidence. There are also studies that have shown increases in cancer related to alcohol consumption, as answered in this question . The more general studies would tend to indicate that the positive benefits outweigh the negative. This is not a clear-cut situation. | {
"source": [
"https://skeptics.stackexchange.com/questions/1059",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/334/"
]
} |
1,064 | While googling about Ben Goldacre, I came across the following reductio ad absurdum argument: Nerd, can you point me to the data that shows that wearing a parachute increases your life expectancy when jumping out of a plane? You see, someone claimed that it is helpful, but there s nothing in the data to support this. I cannot find any reference to a double blind trial, I can’t find any peer-reviewed studies, and I cannot even find a pilot study comparing survivability with or without a ‘chute. Is it bad science to rely on anecdotal data here? If not, why not? I guess there's the hypothetical about "What would you do if there weren't any peer-reviewed papers about parachutes?", but I'm interested in whether there's any scientific papers supporting the use of parachutes. The papers don't necessarily have to involve double-blinded randomized experiments on humans. For example, the paper High-rise syndrome in cats concluded that the survival rate of cats increased as the height increased, possibly because cats become more relaxed once they reach terminal velocity, and possibly because it has more time to prepare for the landing. Rather than a double-blinded study, they observed 132 cats who had been "diagnosed" with high-rise syndrome over a 5-month period. | The author of that comment is probably referencing Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials which is pointing out the absurdity of radical evidence based medicine. From the abstract: Conclusions As with many interventions intended to prevent ill health, the effectiveness of parachutes has not been subjected to rigorous evaluation by using randomised controlled trials. Advocates of evidence based medicine have criticised the adoption of interventions evaluated by using only observational data. We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute. A discussion follows and I'm content with this comment that addresses the absurdity of demanding an explicit medical answer: Not the common sense but simple laws of physics can prove the effectiveness of the parachute as a life saving intervention. When a person jumps from a height accelerates towards the earth and eventually reaches the “terminal velocity”. For an average person this terminal velocity is about 200km/hour and it takes only about 3 seconds to reach the terminal velocity. The damages caused to an individual hitting the ground at this speed is not just broken arms! Now, introducing a parachute reduces this terminal velocity to less than 10km/hour. This is comparable to crashing an old car without any airbags to a solid concrete wall at 200km/h and 10km/h. According to Wikipedia (and other sources) the Guiness world record for falling without a parachute belongs to Vesna Vulović who fell 10,000m, with several more people falling over 5,000m during WWII. The Wikipedia article also references a pub med article Ten years of experience with falls from a height in children. that states Falls from a height are a major cause of accidental death in urban children. The medical and social data on 61 children admitted over the last decade for falls of one or more stories were reviewed. Seventy-seven percent of the children survived. Of the children who fell three stories or less, all survived (100%). Fifty percent mortality occurred between the fifth and sixth floors. Seventy-seven percent of the falls were accidental and 23% of the children jumped or were pushed. The 96% decrease in accidental falls from windows since 1979 demonstrates that the "Children Can't Fly" program in New York City has almost eliminated accidental falls from windows in our hospital population. There are countless of articles about the injury rate of parachuting and base jumping that all give about the same numbers. Parachuting injuries: a study of 110,000 sports jumps from 1987 states: A total of 110,000 parachute jumps resulted in six (0.005%) fatalities and 155 (0.14%)
cases, requiring medical treatment. The latter group sustained 176 injuries of which 36.9% were significant soft tissue lesions and 63.1% fractures. Landing is the most dangerous part of the parachuting procedure, causing 83.8% of the accidents, while 9.3% were caused by faults during opening of the parachute. On the age of those that participated it states: The mean age was 29.3 years, range 16-62 years. Working with the assumption that survivability doesn't increase with falling distance, and that age doesn't profoundly diminish the damage cause to humans by rapid deceleration, we must conclude that it's the parachutes responsible for the increase in survivability from 50% when falling from the fifth to sixth floor to 99.995% when jumping out of an airplane. TL;DR Is the use of parachutes supported by peer-reviewed papers? Yes, there are many papers that that show that parachutes are being used. Does the literature show that parachuting increases survivability over free-falling? Yes, indirectly. | {
"source": [
"https://skeptics.stackexchange.com/questions/1064",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/104/"
]
} |
1,091 | Not too long ago a story about a study examining mummies for the prevalence of cancer caused a flurry of articles in the media claiming that cancer is a man-made disease . The researchers claim that cancer was very rare in ancient egypt compared to modern times. In their press release about the study the author states “In industrialised societies, cancer
is second only to cardiovascular
disease as a cause of death. But in
ancient times, it was extremely rare.
There is nothing in the natural
environment that can cause cancer. So
it has to be a man-made disease, down
to pollution and changes to our diet
and lifestyle.” Are those claims valid? What evidence is there about the environmental causes of cancer? I'm not just asking about this specific study, but also about other studies showing how important environmental factors are in the incidence of cancer. | I know of no studies but it is well-known that life expectancy has increased drastically since ancient Egypt and that cancer prevalence increases with age. About the first point, life expectancy in ancient Egypt was around 25 years, and even in the middle ages no more than 30 years. Compare that to today’s 67 years. Granted, once you take infant mortality out of the equation life expectancy grows – but it still was much less than today, and more importantly, it was often less than 50 years . The second point is due to a number of factors but it all boils down to cell aging and accumulating effects of detriment mutations. There are occurrences of cancer in young people and even in children, but mostly, it is “ a disease found in people over the age of 50 ”: according to SEER data , just 95 people below 50 get cancer for 1449 incidences above 50 . Combined, it isn’t surprising to see that cancer is much more common now than it was then. Superficially, no further reasons are needed to explain this phenomenon. Furthermore, animals (e.g. chimpanzees ) and even plants can get cancer, too – so this isn’t a problem that is partial to humans (though that doesn’t preclude new environmental causes). Apart from that, the quote is complete nonsense : There is nothing in the natural environment that can cause cancer Well … no . There are a lot of things in the natural environment that can and do cause cancers. The most glaring point is natural sources of high radiation, such as uranium ore and of course the sun . But more sources exist, such as viruses , infectious diseases and diet . | {
"source": [
"https://skeptics.stackexchange.com/questions/1091",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/5/"
]
} |
1,092 | Is there any scientific backing to the claim that reading in dim light damages your eyes? Related to: Does watching television damage the eyes? | No, there isn’t. This is a very old urban legend – nothing more: Suboptimal lighting can create a sensation of having difficulty in focusing. It also decreases the rate of blinking and leads to discomfort from drying, particularly in conditions of voluntary squinting. The important counterpoint is that these effects do not persist. | {
"source": [
"https://skeptics.stackexchange.com/questions/1092",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/631/"
]
} |
1,101 | In the book Ishmael by Daniel Quinn, there's a passage that claims "Takers" (i.e. modern man) are the only thing in nature that hunt down competitors, destroy or otherwise deny someone else food. Are there strong arguments to be made that other animals exhibit the same behavior? "you may compete to the full extent of your capabilities, but you may not hunt down competitors or destroy their food or deny them access to food. In other words, you may compete but you may not wage war." All species inevitably follow this law, or as a consequence go extinct. The Takers believe themselves to be exempt from this Law and flout it at every point. I'm disqualifying Kleptoparasitism which directly benefits the thief as an answer. There's no need to make a case about animals that do all 3 of the above mentioned things, refuting one of them is enough. | Ants are remarkable for waging war and enslaving and cultivating other species . You may also be interested in a paper documenting ants being hostile to their neighbors. | {
"source": [
"https://skeptics.stackexchange.com/questions/1101",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/631/"
]
} |
1,118 | Are personal electronics (of present or recent past; e.g. cell phones, mp3 players, iPads) a risk to commercial air travel? Is the typical request to "turn off all personal electronic devices" based on any reasonable data? | From ABC News (2007): An aviation safety database maintained
by NASA shows a handful of incidents
each year reported by pilots who
suspected cell phones and other
electronic devices had caused a
problem during flight. Despite these
reports, not a single air crash has
been proven to be caused by the use of
a cell phone onboard a plane . John Nance, an ABC News consultant and
veteran airline pilot, says there's
little reason to worry about cell
phones interfering with an airplane's
navigational equipment. He says an
airplane's electronic systems are "all
heavily shielded . That means that
stray signals cannot get into those
systems." The airlines can't allow cell phones
to be used in flight until the
technology has been proven safe.
However, according to Nance, the
Federal Communications Commission and
the Federal Aviation Administration
"have not done their job over about a
25-year period. And the airlines have
quite properly said … if you're not
going to tell us, then we're just
going to default to the most
conservative position and say we're
not going to use them in the air ." Here is a study done in 2003 that concludes " Cellphones and other electronics are more of a risk than you think " regulations already permit a wide
variety of other portable electronic
devices--from game machines to laptops
with Wi-Fi cards--to be used in the
air today. Yet our research has found
that these items can interrupt the
normal operation of key cockpit
instruments, especially Global
Positioning System (GPS) receivers ,
which are increasingly vital to safe
landings. ... There is no smoking gun to this story: there is no definitive instance of an
air accident known to have been caused
by a passenger's use of an electronic
device . Nonetheless, although it is
impossible to say that such use has
contributed to air accidents in the
past, the data also make it impossible
to rule it out completely . ... Consumer devices that meet FCC
emission limits can exceed safe
interference limits set by the FAA for
avionics, because the FCC and the FAA
do not harmonize their regulations. ... At present, we believe that passenger
use of electronics on board commercial
aircraft should continue to be limited
and that passengers should not be
allowed to operate intentionally
radiating devices such as cellphones
and wireless computer equipment during
critical stages of flight . Let's presume there is a 0.01% chance that cell phones can cause a crash. Worldwide there will surely be more than 10.000 flights per day. So even with such a low percentage it would mean at least one crash per day. Looking at it this way I can understand the ban. | {
"source": [
"https://skeptics.stackexchange.com/questions/1118",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/858/"
]
} |
1,128 | Is there any concrete, solid proof of this space odyssey? Is there a way that I personally have a look a it? Let's say, with a nice telescope ? | Besides the command module the rocks a dozen of people who went there , 400,000 scientists and engineers , TV footage and photo material , an actual mirror we left there that we can shine a laser on no we don't have any evidence ;-) The artifacts of the mission have been seen by the Lunar Reconnaissance Orbiter and probably other satellites. They can't be seen from Earth. | {
"source": [
"https://skeptics.stackexchange.com/questions/1128",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/873/"
]
} |
1,138 | All over the world there are signs similar to this, is there the slightest bit of support for the danger of using a cell phone at the gas station? Related to: Are personal electronics a risk to commercial aviation? Resources: Mythbusters review Brainiac reviews if cellphones can set fire to a caravan filled with gas | Snopes does a much better job of explaining this than I would. Basic summary. Not only has there not been a single confirmable incident reported worldwide that can be attributed to cell phones, no one has been able to reproduce it in a lab. If you take apart your phone and make an ignition switch out of it. and if the station you go to has poor vapor controls, you might succeed in igniting fumes from the pump. Otherwise the only thing that's likely to even generate enough spark/heat to ignite fumes is if your phone's lithium battery ignites. There are a couple of documented cases of that, so if you're buying cheap batteries in china then in an exact perfect scenario at the pump, it could happen. | {
"source": [
"https://skeptics.stackexchange.com/questions/1138",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/631/"
]
} |
1,164 | Those arguing for more profiling quite frequently claim that while not all Muslims are terrorists, most terrorists are muslim. Is there data to show that more than 50% of terrorists attacks can be attributed to any one religious or political affiliation. To clarify some. Terrorism : The use of violence, outside of war, to manipulate or coerce a population. Region : US and Europe | The answer to this question varies greatly, depending on country you are from. If you're from the Netherlands, Islamists represented 100% of the individuals suspected of terrorism each year from 2006 to 2009 (between 2 or 6 per year), except in 2007. On the other hand, if you are from France, then, while Islamists do represent a sizable number of the arrested suspects, the percentage is far lower (342 out of 1468, or 23.2%) in the same timespan. In the United States, more than 80% ( 186 out of 228 ) of all convictions tied to international terrorist groups since 9/11 involve defendants driven by a radical Islamist agenda. The European Union has a graph of arrested terrorism suspects by Member State in its Terrorism Situation and Trend Report 2010 : It also states that: The number of arrests relating to Islamist terrorism (110) decreased by 41 % compared to 2008, which continues the trend of a steady decrease since 2006. Since you're interested in those numbers to discuss more profiling, arrested suspects are not what is interesting to look at. Instead, that would be successful attempts. There are few successful attempts, at least in Europe, over the last few years. For example, there was only one attempt in 2009: ..and it was foiled. The preceding years are not very different. In the recent years, Islamist terrorism has not been very successful. For example, the Terrorism Situation and Trend Report 2008 , which reports on terrorism in the European Union in 2007, states that: With regard to Islamist terrorism, two failed and
two attempted attacks were reported for 2007. As
in 2006, failed or attempted Islamist terrorist
attacks took place in the UK, Denmark and
Germany. Police investigations into the attempted
attacks in Denmark and Germany have shown
that the intended targets were likely to be located
on their national territory. However, as the report notes, "The failed and attempted attacks mainly aimed at causing indiscriminate mass casualties." As such, even one successful attack can lead to a large amount of causalities. Resources used: Terrorism Situation and Trend Report 2007 Terrorism Situation and Trend Report 2008 Terrorism Situation and Trend Report 2009 Terrorism Situation and Trend Report 2010 | {
"source": [
"https://skeptics.stackexchange.com/questions/1164",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/189/"
]
} |
1,178 | Has it been proven that being exposed to WiFi waves is harmful? | WIFi is non-ionising radiation and so has similar issues to other radiation using similar frequencies such as mobile telephones and microwave ovens. These produce heating effects. WiFi is not focused, so any impact should be very small and perhaps not measurable. I am not aware of any health studies specifically on WiFi. There have been studies on mobile phones which has shown that while the phone is in use and held next to the head, there is small but measurable heating effect on human tissue. My guess is that it has less impact than standing at right angles to the Sun so one side of the head gets warmer faster than the other. Even then, these studies have produced no evidence that this has any health impact, positive or negative: A large body of research exists, both epidemiological and experimental, in non-human animals and in humans, of which the majority shows no definite causative relationship between exposure to mobile phones and harmful biological effects in humans. And per Dr. Michael Clark of the HPA , WiFi is a fraction of the energy of a cell phone : “When we have conducted measurements in schools, typical exposures from wi-fi are around 20 millionths of the international guideline levels of exposure to radiation. As a comparison, a child on a mobile phone receives up to 50 per cent of guideline levels. So a year sitting in a classroom near a wireless network is roughly equivalent to 20 minutes on a mobile. If wi-fi should be taken out of schools, then the mobile phone network should be shut down, too — and FM radio and TV, as the strength of their signals is similar to that from wi-fi in classrooms.” The Sun does emit ionising radiation (ultra violet) and that has significant health effects such as sunburn, pigmentation changes and Vitamin D production. WiFi's impact, if anything, is nothing like this. | {
"source": [
"https://skeptics.stackexchange.com/questions/1178",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/873/"
]
} |
1,202 | I know that there has been found evidence pointing to simple life on Mars , but has any of the projects like SETI found anything that could point to intelligent alien life out there? By alien life, I mean from another planet than Earth.
By intelligent, I don't necessarily mean something we can communicate with. I'm looking for is what evidence there is of life outside earth | If there were and any proof of intelligent life from SETI, it would be right on their page, and all over world-news. It just hasn't happened yet. That may be due to the fact that we just haven't looked in the right place, or in the right ways yet, or because we lack the ability to detect them, or because they are not there. We just don't know. As for microbial life on Mars, there isn't any conclusive evidence for that yet, though there are some interesting signs, including the possibility of liquid water . There are other interesting signs that are mentioned on the Wikipedia page that you linked to, and scientists around the world are looking to investigate them, though Mars is difficult to study. As of the time of this writing though, we can not conclusively say that there is any life on Mars. As we like to say around here though, absence of evidence is no evidence of absence. | {
"source": [
"https://skeptics.stackexchange.com/questions/1202",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/971/"
]
} |
1,244 | Having read this Guardian article it seems LSD is a much less harmful drug (both to the user and to others) than alcohol. I live in the UK, where alcohol is legal to buy from age 18 (and to drink from even younger), but LSD is a class A drug - the highest classification. What's the basis for this classification? Update: Amusingly, it seems LSD can actually help alcoholics kick the habit . | I hate to answer with a direct quote from wikipedia , but they do such a good job of summarising the health risks of LSD: Whilst there have been no documented human deaths from an LSD overdose, LSD may temporarily impair the ability to make sensible judgments and understand common dangers, thus making the user more susceptible to accidents and personal injury and cause signs of organic brain damage-impaired memory and attention span, mental confusion or difficulty with abstract thinking. However LSD is physiologically well tolerated and there is no evidence for long-lasting effects on the brain or other parts of the human organism. That's all that can really be said. There's an interesting graph right next to that paragraph on wikipedia, depicting the fact that LSD (as well as Marijuana and Psilocybin mushrooms) has a VERY low active dose to lethal dose ratio (meaning essentially no documented deaths from an overdose). The danger of LSD, Marijuana and Psilocybin is NOT a toxic or physiologically harmful effect of the drug itself; it's the effect it has on the user's mind. In a perfectly controlled environment, LSD would not have any physiologically harmful effects when taken in recreational doses . But in the real world, the effect can sometimes be that the way the user perceives his surroundings changes drastically, while also impairing the user's ability to make reasoned decisions. You're right in saying that alcohol does more physiological damage than LSD, and it also has a much higher addictive potential. However, those are not the properties that make LSD dangerous. | {
"source": [
"https://skeptics.stackexchange.com/questions/1244",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/922/"
]
} |
1,246 | This is a typical extract form a blog post about Orbs , Reading an article about orbs, the
mysterious lights sometimes appearing
in photographs, I was reminded of how
little we know of the world
surrounding us. And here is an example image: Could they really they Ghosts, Spirits or Entities from another dimension? | Orbs are photographic artefacts – specifically bits of airborne dust, water droplets, insects etc. caught in the flash of a camera. They appear out of focus because they are so close to the lens of the camera in an area called ‘The orb zone’ which is between the camera lens and the ‘point of focus’ in a photograph (namely the object you are taking a photo of, such as a person.) When the flash of a camera goes off it will reflect off of the airborne artefacts in ‘the orb zone’ and the position between the lens and the ‘point of focus’ will cause the light reflection to appear as a circle of confusion. An orb is what a professional photographer would call a circle of confusion, an out of focus highlight in the photo. When you take a photograph that has out of focus objects in it you will notice that the out of focus objects don’t just go fuzzy – they turn into small overlapping circles of light and the larger the circle, the fainter it is, because the light is more spread out until eventually the circles will become so large and faint that they disappear all together. This could explain why some orbs appear larger and fainter than others rather than the idea that the spirit orb is further away from the camera. To confuse an artefact in front of a camera lens for a spirit manifestation is an easy mistake to make if you do not research into the subject and rely upon pseudo-scientific theories. A study was done by ‘Paranormal Site Investigators’ who are based in Swindon into the orb phenomena that showed how it's unlikely that these balls of light are caused by ghosts. The study can be found here: https://web.archive.org/web/20110717020812/http://www.theorbzone.com/ | {
"source": [
"https://skeptics.stackexchange.com/questions/1246",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/4/"
]
} |
1,266 | In Noah's Ark myth God sent 40 days of rain to flood the Earth.
Are any such long periods of persistent rain recorded? What kind of disaster could happen to cover all continents with water? | The talk.origins archive documents an extensive list of claims about the flood . It also includes sections discussing the Ark and the various problems that aspect of story has. There's also a separate article dedicated to the flood . Are any such long periods of persistent rain recorded? I don't know about persistent rain, but Seattle has had 30 days of measurable rainfall twice in the past 60 years. It isn't unreasonable to believe that other locations could have had a longer, more aggressive chain of storms, and it's also not unreasonable to expect that there'd be problems with local waterways flooding as a result. What kind of disaster could happen to cover all continents with water? There are a few frequently suggested sources of the water. They all fail simple tests. If there was supernatural involvement, we'd also expect to see global evidence of a great flood, but this is absent. The most logical explanation given the lack of evidence is that the story is mythical. As @Sklivvz posted in the comments the flood story probably originates from part of the Epic of Gilgamesh which follows the same general plot. The resident deity is upset with humanity and selects one righteous man to be saved. Instructions are given to build a large boat to save all of the animals and the man's family. It rained, though only for six days. Birds are sent out, one doesn't come back, a mountain is found, a sacrifice is made, the resident deity is pleased / remorseful and promises not to do that again. The talk.origins site hasn't been updated in a while. There was some evidence uncovered somewhat recently that suggested that the myth may have originated when the Black Sea grew rapidly after an influx of water from the Mediterranean in ~5600 BCE. In 2009, National Geographic published a follow-up that suggested the growth in the Black Sea was not as catastrophic as first thought, and might not really be the origin of the myth. | {
"source": [
"https://skeptics.stackexchange.com/questions/1266",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/123/"
]
} |
1,267 | Is the famous image of a face on Mars a trick of the light or an artificial structure reprinting a face? | No, it's just a myth. That picture had a low resolution and a particular light angle made it look like a face, but see this: Here's what it looks like from the oblique: It's clearly not a face. What the picture actually shows is the Martian equivalent of a butte or mesa -- landforms common around the American West. "It reminds me most of Middle Butte in the Snake River Plain of Idaho," says Garvin. "That's a lava dome that takes the form of an isolated mesa about the same height as the Face on Mars." -- source | {
"source": [
"https://skeptics.stackexchange.com/questions/1267",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/4/"
]
} |
1,276 | I can not even find one Peer-Reviewed Double Blind Study of any vaccine. Can you point out some studies for me, if they are available? | Immunogenicity and reactogenicity of a 13-valent-pneumococcal conjugate vaccine administered at 2, 4, and 12 months of age: a double-blind randomized active-controlled trial . Immunogenicity of bivalent types 1 and 3 oral poliovirus vaccine: a randomised, double-blind, controlled trial. Efficacy of pentavalent rotavirus vaccine against severe rotavirus gastroenteritis in infants in developing countries in Asia: a randomised, double-blind, placebo-controlled trial That are just a few results from a quick search, there are studies done for every approved vaccine. I'm using the US system as an example, but it will be similar in other countries. In the US the FDA has to approve vaccines : Pre-marketing (pre-licensure) vaccine
clinical trials are typically done in
three phases, as is the case for any
drug or biologic. Initial human
studies, referred to as Phase 1, are
safety and immunogenicity studies
performed in a small number of closely
monitored subjects. Phase 2 studies
are dose-ranging studies and may
enroll hundreds of subjects. Finally,
Phase 3 trials typically enroll
thousands of individuals and provide
the critical documentation of
effectiveness and important additional
safety data required for licensing. At
any stage of the clinical or animal
studies, if data raise significant
concerns about either safety or
effectiveness, FDA may request
additional information or studies, or
may halt ongoing clinical studies. So any vaccine will have to be shown safe and effective in clinical trials to get approved. They also continue to investigate the safety of the vaccines: The FDA continues to oversee the
production of vaccines after the
vaccine and the manufacturing
processes are approved, in order to
ensure continuing safety. | {
"source": [
"https://skeptics.stackexchange.com/questions/1276",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/-1/"
]
} |
1,311 | One idea I used to hear a lot about was that when people are near-death and saved by medical science that they sometimes see "a light at the end of a tunnel" in a vision. Today I read about an article about a new best-seller from an ambitious 4-year-old in Nebraska : 'I met great granddad...and he had wings': Boy who 'went to heaven' is now best selling author . Here's his #1 New York Times Bestselling book "Heaven is for Real" on Amazon : The only problem is that I remember seeing shows on TV that suggest near-death experiences can be repeated in a controlled environment . Is there any evidence to suggest that near-death experiences and "the light at the end of the tunnel" have a scientific explanation? | There is ample scientific explanations for the physiological reactions that people experience. From PubMed (my emphasis): The Near-Death Experience (NDE) is a dissociative mental state with characteristic features. These can be reproduced by ketamine which acts at sigma sites and blocks N-methyl-D-aspartate (NMDA) linked phencyclidine (PCP) receptors to reduce ischaemic damage. Endogenous ligands, alpha and beta-endopsychosin, have been detected for these receptors which suggests an explanation for some NDE's: the endopsychosins may be released in abnormal quantity to protect neurons from ischaemic and other excitotoxic damage, and the NDE is a side effect on consciousness with important psychological functions. The light in the tunnel effect is an easy one, since I have personally experienced it numerous times in a high-G environment. Your eyes naturally create a tunnel effect as they start to lose oxygen. As for seeing loved ones, in the case of this particular book, that is more likely a post hoc occurrence for financial gain as well as societally influenced expectations. The personal history and background of the boy Colton, and the author Todd Burpo, align exactly with what they wrote about (isn't it funny that no one ever experiences a "vision" that would be opposed to their expectations and personal history, like a christian seeing Vishnu for instance?). And it is established that autobiographical memories can be implanted in individuals , and that children are especially susceptible to this. Loftus (1997) investigated memory distortion and the relation with the degree of confidence in the existence of a false memory. She calls this phenomenon the "misinformation effect". She observed that if witnesses of an event are later exposed to new and misleading information about it, their recollections become distorted (Loftus, 1997). Loftus was able to empirically demonstrate this phenomenon with autobiographical memories. With corroboration from the participants' family members, Loftus was relatively successful at implanting false autobiographical memories. EDIT TO ADD : I just found this article today that is relevant to this answer . This week, in “ The neurology of near-death experiences “, Alex debunks the religious trappings that attach to the “out-of-body” and similar experiences that occur in conjunction with operations and medical episodes. In particular, he shows that experiences such as dreamlike states, tunnel vision, and leaving and returning to one’s body are all phenomena that have well-understood medical causes. Some of them can even be reproduced by stimulating people’s brains. I suggest anyone interested in the subject check out the links. | {
"source": [
"https://skeptics.stackexchange.com/questions/1311",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/49/"
]
} |
1,328 | I'm seeing some conspiracy theories making the rounds which claim that car-manufacturers are intentionally making cars that aren't as fuel efficient as they used to be. They often point to the Geo Metro and claim it got 50 mpg, which is better than even the modern hybrids. Were cars like the Geo Metro really more fuel efficient than modern cars in the same class, and if so why? 1995 Geo Metro Fuel Economy 2010 Toyota Yaris Fuel Economy 2010 Nissan Sentra Fuel Economy | There are a few things at work here: Safety requirements and standards are much more strict now than they were 10, 15, or 20 years ago. These added components (such as ABS, etc) along with modern luxuries (such as power steering, etc) have added a lot of weight to modern cars. The Geo Metro you reference had a curb weight of just 820kg (about 1800 lbs), while the Yaris has a curb weight of 2311 lbs. That's a difference of 28.3%! The EPA changed the standard way to estimate fuel economy in 2008. Here is a summary. The standards are now more strict, so I believe every estimate dropped when these went into effect. Perhaps the fuel economy in general has gone down to make room for better performance as well, but I think that impact is minimal compared to the 2 items above. Just for fun here is a link suggesting the opposite. They managed to average 48.5 MPG with the 2011 V6 Ford Mustang (this was not an EPA rating, but a test track rating, of course). http://usnews.rankingsandreviews.com/cars-trucks/daily-news/100625-2011-Ford-Mustang-V6-Nets-48-5-MPG-in-Track-Test/ | {
"source": [
"https://skeptics.stackexchange.com/questions/1328",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/770/"
]
} |
1,333 | It is sometimes heard that automobile manufacturers design low-quality parts that wear out or break easily, so that they can make money on the repair or replacement of these parts. I believe this to be true, and not just limited to automobile manufacturers. Is there any evidence to support this claim? | I think this phenomenon is explained by a simple economic rationale: Manufacturers compete on price, but have to control quality to a chosen fixed standard . For example, it's extremely rare to buy a new car that doesn't start. Cars are clearly quality checked for safety and their parts are made to last at least as long an the warranty. A company would lose money otherwise. The final step is inspection of the completed cars. Each car undergoes strict inspections of 1,500 to 2,000 different things to make sure the brakes, windshield wipers, lights, and other parts work. Only after the car passes all inspections is it shipped to the customer. -- source So, given a set quality, the competition is on price . Manufacturers will tend to use pieces that are good enough to last, but mostly cheap - cheaper than the competition. Therefore, in a way you are right, using cheap parts they compete better so they make more money than otherwise - however I would say they are pushed by economic forces and not mere greed. On the other hand, it just as clear that they use all available dirty tricks, like seriously overcharging for parts (one front lamp 400€?), in the after market . This is where there is basically no competition pressure. The European Commission’s latest report on car prices shows that prices fell slightly, in real terms, in the European Union in 2009 and also converged within the EU's single market. At the same time prices for repair and maintenance services as well as spare parts continued to rise well above inflation confirming the need for the stricter competition rules in place for the sector since the 1st of June. -- source | {
"source": [
"https://skeptics.stackexchange.com/questions/1333",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/1080/"
]
} |
1,355 | In this Politico Article dated 8/5/10 the results of a poll taken on President Obama are discussed: The poll of 1,018 adults shows 27
percent of Americans believe the
president was “probably” or
“definitely” born in another country ,
compared with 71 percent who think he
was born in the United States. So 1 in 4 Americans do not believe that President Obama is really a natural born citizen . Is there any evidence to back up the Birther claims that Obama is not a natural born citizen? | One piece of evidence is the long-form birth certificate showing that Barack Obama was born in Honolulu on Hawaii: ( long-form on whitehouse.gov in PDF format ) The reissued short-form birth certificate: You can find a detailed examination of the birth certificate on Factcheck.org . They conclude in their investigation FactCheck.org staffers have now seen,
touched, examined and photographed the
original birth certificate. We
conclude that it meets all of the
requirements from the State Department
for proving U.S. citizenship. Claims
that the document lacks a raised seal
or a signature are false. We have
posted high-resolution photographs of
the document as "supporting documents"
to this article. Our conclusion: Obama
was born in the U.S.A. just as he has
always said. The director of Hawaii’s Department of Health, Chiyome Fukino, also confirmed that the certificate is genuine: "I, Dr. Chiyome Fukino, director of
the Hawai'i State Department of
Health, have seen the original vital
records maintained on file by the
Hawai'i State Department of Health
verifying Barack Hussein Obama was
born in Hawai'i and is a natural-born
American citizen," Fukino said in a
statement. "I have nothing further to
add to this statement or my original
statement issued in October 2008, over
eight months ago."
-- source The Barack Obama birth announcement, published in The Honolulu Advertiser on Aug. 13, 1961: | {
"source": [
"https://skeptics.stackexchange.com/questions/1355",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/49/"
]
} |
1,367 | I was recently surprised to learn that many Americans have been circumcised even though their parents had no religious motivation to go through with it. This in strong contrast with my home country where doctors are frequently refuse to perform the procedure even for religious reasons. The number of circumcised men in America is over 50% according a page I found that tracks circumcision rate in the US . These seem to be primary motivators for circumcision for non-religious reasons: It's cleaner. It's healthier. It leads for increased feeling and better sex for men. Fear of their child being alienated. How much credibility do these have, are there other non-religious motivators and do the benefits really out weight the downsides and the risk of surgery? | There is basically no scientific consensus to support " circumcision would lead to a better life quality ". Here 's a much bigger article with a slightly different approach and whole lot of different sources while independently coming basically to the same conclusions. A circumcised penis is not necessarily cleaner nor healthier . That depends mostly on personal hygiene. Circumcision is a minor surgical procedure and, like all procedures, has potential to cause complications . There is an ongoing debate about whether circumcision increases or decreases overall likelihood of transmitting disease. For instance, the CDC used to only claim that circumcision reduces the risk that a man will receive HIV from a female partner but perhaps after this claim being disputed by different organizations they now added " However, male circumcision confers only partial protection and should be considered as only one of several other prevention measures ". There are legitimate concerns that circumcision might reduce sexual enjoyment. The corona below the foreskin is more sensitive than the penile sheath (or foreskin) which is removed during circumcision. Supposedly the corona gradually loses sensitivity due to constant contact with other surfaces. After much debate (keeping old link) there still is no consensus on this . From a social perspective, many US women prefer circumcised men and even demonstrate discomfort around uncircumcised ones. One reason might be the high rate of circumcision. Apparently the US is one of the very few developed countries doing the procedure so prominently, and maybe the biggest in population. From an ethical perspective, some say it's a human rights issue. Grown men can and should decide for themselves if they'd like to undergo the procedure. Infants have no choice but they are still a big target audience in the US . Lastly, for the TL;DR; folks, there are at least two celebrity skeptics who spoke out against circumcision: Joshie Berger, in an interview for the SGU ; and Penn Jillette on his show Bullshit! . Here's a quote: "... Suddenly circumcision prevented diseases. Now we find that's bullshit too so the only excuse we have now is conformity." | {
"source": [
"https://skeptics.stackexchange.com/questions/1367",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/631/"
]
} |
1,368 | There have been a lot of claims made about the circumstances surrounding the events of 9/11 and Building 7 in particular . The central claim regarding Building 7 , that I have heard personally, is that Building 7 fell in such a perfect fluid motion that its collapse had to be due to a controlled demolition . Furthermore since Building 7 wasn't hit by a plane directly, it is claimed that there can be no other explanation for how the building collapsed in such a seemingly controlled fashion. Is there any evidence to support the claims that Building 7 was destroyed in a directly controlled fashion? | No. Fires ignited by falling debris (from WTC 1) are the sole cause of the WTC 7 collapse. Short answer: Debris from the collapse of WTC 1, about 350 ft. to the south,
impacted WTC 7, igniting fires on at least 10 floors. Other than starting the fires, the debris impacts were not a
contributing factor. Fires on six of those floors grew from the time of the debris
impact (10:28:22 a.m.) and lasted until the building collapsed
(5:20:52 p.m.). After several hours, the heat absorption ability of the
fire-proofing began to fail. The building's structural steel began to
soak up heat from the fires. A ''seated connection'' was used for some of the girders framed to
interior columns. The girder was held by four "erection
bolts" (''girders'' span between columns; ''beams'' span
between girders). A 13.7 m (540 in.) long W33x130 beam heated uniformly to 600 °C will
expand along its length by 4.5 inches. In doing so it will produce a lateral force of 6.9 million pounds
(30.7 million newtons). The four erection bolts resisting this force had a total shear
capacity of 0.180 million pounds (i.e., 2.6 percent of the possible
force). By the time the girders reached 164 °C the four bolts had failed
(i.e., torn in two, ripped apart, cleaved in twain, etc.). With the failure of the bolted connection, further thermal
expansion of the floor beams pushed a 13 th floor girder,
between Columns 79 and 44, off its seat. The flooring system on Floor 13 subsequently failed, collapsing
onto the floors below, resulting in the collapse of floors 12 through 6. The floor collapse left more than 150 ft. of Column 79 without
lateral support. Without structure transferring load laterally, Column 79 buckled
and failed. The transfer of load, once supported by Column 79, overwhelmed the
structural capacity of the other columns. They too failed. After burning for 6 hours and 52 minutes, WTC 7 suffered a
fire-induced progressive collapse. The building was completely
destroyed. Long answer: 1. Erection bolts are not structural connections In a seated connection, the beam or girder was supported by the seat,
which was welded to the column. Bolts were installed that fasten the
beam or girder to the seat for erection purposes These erection bolts
did not carry any gravity load; rather, they were installed to insure
that the beam or girder was held in place during erection. NIST found
no evidence that the girders or beams in WTC 7 were welded to the
seats. In a similar way. an angle or plate was bolted to the top
flange to prevent the beam or girder from twisting, but there was
little restraint to bending in the plane of the beam. Consider the girder that spanned between Column 79 on the interior of
the building and Column 44 on the exterior. Thermal expansion of this
girder would have loaded the erection bolts in shear, since (1) there
were no shear studs anchoring the girder to the slab (and thereby
restraining elongation), and (2) the columns were prevented from
lateral movement because they were embedded in the floor slabs which
had considerable in-plane stiffness. Additionally, the expansion of
floor beams that framed into this girder, because the framing was
asymmetrical, tended to add additional shear load to the erection
bolts. The combination of these two shear loads could have failed the
bolts in shear. If the erection bolts were to fail, then there would
be no positive attachment preventing the girder from being pushed off
the seat. Source: (NCSTAR 1-9) VOLUMES 1 and 2 , page 348. 2. Thermal expansion will break stuff The first failures observed were of the shear studs, which were
produced by axial expansion of the floor beams, and which began to
occur at fairly low beam temperature of 103 °C. Axial expansion of the
girder then led to shear failure of the bolts at the connection to
Column 79; and, at a girder temperature of 164 °C, all four erection
bolts had failed, leaving that end of the girder essentially
unrestrained against rotation. Continued axial expansion of the floor
beams pushed the girder laterally at Column 79, as shown in Figure
8-26 , in which failed shear studs and bolts were evident. When the
beam temperatures had reached 300 °C, all but three shear studs in the
model had failed due to axial expansion of the beams, leaving the top
flanges of the beams essentially unrestrained laterally. Continued
axial expansion of the girder caused it to bear against the face of
Column 79, generating large axial forces that led to failure of the
bolts connecting the girder to Column 44. When the girder temperature
had reached 398 °C, all four erection bolts at Column 44 had failed,
leaving the girder essentially unrestrained against rotation at both
ends. After failure of the erection bolts in the seat at Column 44,
continued axial expansion of the floor beams pushed the girder
laterally, where it came to bear against the inside of the column
flange. Axial compression then increased in the floor beams, and at a
beam temperature of 436 °C, the northmost beam began to buckle
laterally. Buckling of other floor beams followed as shown in Figure
8-27(a) , leading to collapse of the floor system, and rocking of the
girder off its seat at Column 79 as shown in Figure 8-27(b) . The
collapse process took time to occur in the LS-DYNA analysis, during
which the temperatures had ramped up to their maximum values in the
simulation. Source: (NCSTAR 1-9) VOLUMES 1 and 2 , page 352. 3. Collapse Initiation The simple shear connection between Column 79 and the girder that
spanned the distance to the north face (to Column 44) failed on Floor
13. The connection failed due to shearing of erection bolts, caused by lateral thermal expansion of floor beams supporting the northeast
floor system and, to a lesser extent, by the thermal expansion of the
girder connecting Columns 79 and 44. Further thermal expansion of the
floor beams pushed the girder off its seat, which led to the failure
of the floor system surrounding Column 79 on Floor 13. The collapse of
Floor 13 onto the floors below-some of which were already weakened by
fires-triggered a cascade of floor failures in the northeast region.
This, in turn, led to loss of lateral support to Column 79 in the
east-west direction over nine stories (between Floors 5 and 14). The
increase in unsupported length led to the buckling failure of Column
79, which was the collapse initiation event. Source: (NCSTAR 1-9)
VOLUMES 1 and 2 , page 611. 4. "Free fall" is a myth To further clarify the descent of the north face, NIST recorded the
downward displacement of a point near the center of the roofline from
first movement until the north face was no longer visible in the
video. Numerical analyses were conducted to calculate the velocity and
acceleration of the roofline point from the time-dependent
displacement data. The instant at which vertical motion of the
roofline first occurred was determined by tracking the numerical value
of the brightness of a pixel (a single element in the video image) at
the roofline. This pixel became brighter as the roofline began to
descend because the color of the pixel started to change from that of
the building façade to the lighter color of the sky. The approach taken by NIST is summarized in NIST NCSTAR Report
1A , Section 3.6, and detailed in NIST NCSTAR Report 1-9 ,
Section 12.5.3. The analyses of the video (both the estimation of the instant the
roofline began to descend and the calculated velocity and acceleration
of a point on the roofline) revealed three distinct stages
characterizing the 5.4 seconds of collapse: Stage 1 (0 to 1.75 seconds): acceleration less than that of gravity (i.e., slower than free fall). Stage 2 (1.75 to 4.0 seconds): gravitational acceleration (free fall). Stage 3 (4.0 to 5.4 seconds): decreased acceleration, again less than that of gravity. :This analysis showed that the 40 percent longer descent time—compared
to the 3.9 second free fall time—was due primarily to Stage 1, which
corresponded to the buckling of the exterior columns in the lower
stories of the north face. During Stage 2, the north face descended
essentially in free fall, indicating negligible support from the
structure below. This is consistent with the structural analysis
model, which showed the exterior columns buckling and losing their
capacity to support the loads from the structure above. In Stage 3,
the acceleration decreased as the upper portion of the north face
encountered increased resistance from the collapsed structure and the
debris pile below. Source: Questions and Answers about the NIST WTC 7
Investigation . Claims, assertions and questions : Many of the claims and assertions by WTC 7 conspiracy theorists can be found at WTC 7 Draft Reports for public comment . The submission by Richard Gage of Architects & Engineers for 9/11 Truth is a good representation of how 911 conspiracy theorists rely on a lack of evidence to somehow draw conclusions (see: argument from ignorance ). Investigation by the National Institute of Standards and Technology * : The National Institute of Standards and Technology (NIST) is responsible for conducting fact-finding investigations of building failures that resulted in substantial loss of life or that posed significant potential of substantial loss of life. Final Report on the Collapse of World Trade Center Building 7 (The results of all NIST WTC investigations can be found at : NIST and the World Trade Center ) NIST: Questions and Answers about the NIST WTC 7 Investigation How did the fires cause WTC 7 to
collapse? The heat from the uncontrolled fires
caused steel floor beams and girders
to thermally expand, leading to a
chain of events that caused a key
structural column to fail. The failure
of this structural column then
initiated a fire-induced progressive
collapse of the entire building. According to the report's probable
collapse sequence, heat from the
uncontrolled fires caused thermal
expansion of the steel beams on the
lower floors of the east side of WTC
7, damaging the floor framing on
multiple floors... How hot did WTC 7's steel columns and floor beams get? Due to the effectiveness of the
spray-applied fire-resistive material
(SFRM) or fireproofing, the highest
steel column temperatures in WTC 7
only reached an estimated 300 degrees
C (570 degrees F), and only on the
east side of the building did the
steel floor beams exceed 600 degrees C
(1,100 degrees F). However,
fire-induced buckling of floor beams
and damage to connections-that caused
buckling of a critical column
initiating collapse-occurred at
temperatures below approximately 400
degrees C where thermal expansion
dominates. Above 600 degrees C (1,100
degrees F), there is significant loss
of steel strength and stiffness. In
the WTC 7 collapse, the loss of steel
strength or stiffness was not as
important as the thermal expansion of
steel structures caused by heat. Some people have said that a failure at one column should not have produced
a symmetrical fall like this one.
What's your answer to those
assertions? WTC 7's collapse, viewed from the
exterior (most videos were taken from
the north), did appear to fall almost
uniformly as a single unit. This
occurred because the interior failures
that took place did not cause the
exterior framing to fail until the
final stages of the building collapse.
The interior floor framing and columns
collapsed downward and pulled away
from the exterior frame. There were
clues that internal damage was taking
place, prior to the downward movement
of the exterior frame, such as when
the east penthouse fell downward into
the building and windows broke out on
the north face at the ends of the
building core. The symmetric
appearance of the downward fall of the
WTC 7 was primarily due to the greater
stiffness and strength of its exterior
frame relative to the interior
framing... Did investigators consider the possibility that an explosion caused
or contributed to the collapse of WTC
7? Yes, this possibility was investigated
carefully. NIST concluded that blast
events inside the building did not
occur and found no evidence supporting
the existence of a blast event... Is it possible that thermite or thermate contributed to the collapse
of WTC 7? NIST has looked at the application and
use of thermite and has determined
that its use to sever columns in WTC 7
on 9/11/01 was unlikely. Thermite is a combination of aluminum
powder and a metal oxide that releases
a tremendous amount of heat when
ignited. It is typically used to weld
railroad rails together by melting a
small quantity of steel and pouring
the melted steel into a form between
the two rails... ...Analysis of the WTC steel for the
elements in thermite/thermate would
not necessarily have been conclusive.
The metal compounds also would have
been present in the construction
materials making up the WTC buildings,
and sulfur is present in the gypsum
wallboard used for interior
partitions... An emergency responder caught in the building between the 6th and 8th
floors says he heard two loud booms.
Isn't that evidence that there was an
explosion? The sound levels reported by all
witnesses do not match the sound level
of an explosion that would have been
required to cause the collapse of the
building. If the two loud booms were
due to explosions that were
responsible for the collapse of WTC 7,
the emergency responder-located
somewhere between the 6th and 8th
floors in WTC 7-would not have been
able to survive the near immediate
collapse and provide this witness
account. * NIST is an agency of the U.S. Department of Commerce. | {
"source": [
"https://skeptics.stackexchange.com/questions/1368",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/49/"
]
} |
1,392 | Jamie Oliver always talks about how processed food is awful, and we should stop eating it. By processed food he means food which is pre-prepared and contains additives. He instead insists that food cooked from fresh local ingredients is much healthier. By reading the ingredients lists on the foods you buy, understanding what you are eating and cooking more fresh food for yourself and your family you can become empowered to make the right food choices. Ingredients lists shouldn't be a long list of unpronounceable things you've never heard of. Avoid processed foods and you will see and feel the benefits. -- source An example of his claims is the following: Well, I think it’s pretty simple really: forty years ago we ate mostly fresh, local food, and we knew where that food was coming from. But then fast and heavily processed foods crept in and totally changed our palettes and food businesses. And ultimately, this food is killing us. Obesity and weight gain are the most obvious symptoms, but the problem I have in telling this story is that there are also loads of skinny people suffering because the garbage they are eating is affecting them in a different, but equally dramatic way. Is there any evidence that food containing preservatives is worse for our health than freshly cooked food? For example, if I were to cook chicken nuggets from fresh ingredients would it be healthier than using pre-made ones? | The fact that the food is merely "processed" doesn't make it bad (the classic example is pasteurized milk - it is also a "processed" food; another is properly frozen vegetables). What CAN make processed food worse than non-processed food is four factors: Addition of certain ingredients that aren't good for you either by their nature (trans-fats) or by the unnatural amount (sodium). The additives can be for preservation (e.g. sugar/sodium), or as replacement for easily perishable ingredients (e.g. trans-fats - see Wiki transfats article or http://www.nap.edu/openbook.php?isbn=0309085373&page=423 ), or to give taste/color (e.g. MSG - which doesn't seem to have a firm scientific consensus on long term effects but a proven potential for short term ill effects in some people). A combination of different ingredients may lead to unexpected chemical reactions producing resulting chemicals that may be harmful. A well known example is Sodium Benzoate turning into carcinogenic Benzene in certain conditions. The quality of ingredients in processed food may not be as high. When you get a hot dog, there's no way for you to examine the meat which went into it for quality as you would the meat you buy from the store. This is because the processing pretty much destroys most indicators of food quality by changing ingredients' texture, mixing them with other ingredients etc... This allows the manufacturer to use lesser-quality ingredient to contain costs (not necessarily pig snouts of urban legend, but just lesser quality cuts etc...). The processing destroys good/useful/healthy properties of food. E.g. heating destroys vitamins. | {
"source": [
"https://skeptics.stackexchange.com/questions/1392",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/686/"
]
} |
1,405 | Popular lore states that generally the lowest temperature of any given day occurs an hour after sunrise, because it takes some time for the heat from the Sun to reach Earth. But, it only takes about 8 minutes for the energy from the Sun to reach Earth. Is there something more complex going on that causes the Earth to take longer to heat up, or is this claim false? | The theory is surprisingly simple. The air and the ground get colder when no sun shines on them and hotter when the sun does. What we measure when we say it's colder is actually the air temperature. The sun's radiation has no effect on thermometers. As you can see in the graph, minimum temperature occurs about 30 minutes to 1 hour after sunrise (hard to be exact with the ticks used). For all dates, minimum temperature occurs at sunrise. Temperature drops throughout the night because of two processes. First, the Earth's radiation balance at the surface becomes negative after sunset. Thus, the surface of the Earth stops heating up as solar radiation is not being absorbed. Secondly, conduction and convection transport heat energy up into the atmosphere and the warm air that was at the surface is replaced by cooler air from above because of atmospheric mixing. Temperature begins rising as soon as the net radiation budget of the surface becomes positive. Temperature continues to rise from sunrise until sometime after solar noon. After this time, mixing of the Earth's surface by convection causes the surface to cool despite the positive addition of radiation and heat energy. -- source 1 The above is a schematic of the typical diurnal cycle of surface temperature (red) and the net energy rate due to incoming solar (black) and outgoing longwave radiation (blue). 1: The source of this material is the COMET® Website at http://meted.ucar.edu/ of the University Corporation for Atmospheric Research (UCAR), sponsored in part through cooperative agreement(s) with the National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce (DOC). ©1997-2010 University Corporation for Atmospheric Research. All Rights Reserved. | {
"source": [
"https://skeptics.stackexchange.com/questions/1405",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/334/"
]
} |
1,414 | Aside from the issue of pesticides there's the claim that organic food has more nutrients, vitamins and minerals than nonorganic food: Organic food is known to contain 50%
more nutrients, minerals and vitamins
than produce that has been intensively
farmed. -- source Given either the US certification or the EU certification for organic food is there evidence that an average organic apple has more nutrients, minerals and vitamins than a nonorganic one?
Does it differ between different vegetables and fruits? | In a word, no. There have been no studies to show significant differences in vitamin levels between organinc and conventionally grown foods. The largest discrepency for vitamin levels (not mineral) is due to preparation, processing and shipment methods. http://www.caseperformance.com/19/nutrient-content-of-organic-vs-conventionally-grown-foods (I could dig out the specific studies if necessary, though they are well cited in the above article) As an addition, since there have been additional studies in the meantime the biggest difference appears to be on the specific crop, and the specific field. After 10 years, the researchers found that tomatoes raised in the organic plots contained significantly higher levels of certain antioxidant compounds. But this is one study of one vegetable in one field. And when the
Stanford researchers looked at their broad array of studies, which
included lots of different crops in different situations, they found
no such broad pattern. Source: http://www.npr.org/blogs/thesalt/2012/09/04/160395259/why-organic-food-may-not-be-healthier-for-you | {
"source": [
"https://skeptics.stackexchange.com/questions/1414",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/196/"
]
} |
1,435 | I've heard numerous times that eating 1 a high quantity of sugar will give you a "sugar high" or "sugar buzz" The high one gets after consuming large amounts of sugar. Also called a "sugar rush." Sugar highs cause twitchiness, spasms, and hyper excitability. Sugar highs do not last very long, and leave a person feeling drained afterwards. -- source Also, I've heard, that for the same reason, giving too much sugar to kids will make them hyperactive. Hyperactivity may be caused by learning disability, an unstable home life, food allergy, food additives, excessive sugar ingestion, heavy metal toxicity, or even the need for glasses. -- source This sounds like bogus to me. Is there any evidence on this claim, or is it just a urban myth? 1: Please assume non-diabetics | Here is a Washington Post article that also says "NO": A stronger type of study is one in
which no one--the kids, the parents,
or the experimenter--knows whether the
snack the child ate was sweetened with
sugar or with aspartame. More than a
dozen such studies have been
conducted, and they show that sugar
does not cause hyperactive behavior or
behavior problems , even when the
researchers make a point of testing
kids whose parents say they are
sensitive to sugar. ... Sugar has also been tested for its
impact on kids diagnosed with ADHD.
Again, there seems to be no effect . ... One interesting study examined
the effect of parental expectation .
Thirty-five boys (aged 5 to 7) who
were reported by their mothers to be
sugar sensitive were given a drink
sweetened with aspartame. Half of the
moms were told that the drink had a
lot of sugar in it, and half were told
it had none . Mothers and sons then
interacted on several tasks (e.g.,
building a Lego house together). Moms
who were told their children had had
sugar later rated their sons’ behavior
during this interaction as more
hyperactive . The bottom line: There’s pretty good evidence that
there is not a physiological effect of
sugary snacks on kids’ behavior , and
some of parent’s perception of an
effect is probably just
that--perception. But there could also
be a psychological effect whereby
sugary snacks are associated with
other factors such as a less regulated
atmosphere or kids’ perception of a
less well regulated atmosphere. | {
"source": [
"https://skeptics.stackexchange.com/questions/1435",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/96/"
]
} |
1,438 | Dr Kent Hovind , a noted American Young Earth creationist , claims that the Earth is only 6000 years old . When I was growing up, I was taught in school that dinosaurs come from at least millions of years ago in Earth's far distant past. So how can the claim about the Earth being 6000 years old be true? Is there any evidence that supports the claim that the Earth is only 6000 years old? | No, there is absolutely no sustainable claim at all that the Earth is young. It was proven through multiple experiments (see bottom of the answer), and whole sciences have been built on the premise of an old Earth. Admitting a 6,000 years old Earth hypothesis equates to denying the validity of the work of all of those. It's clearly a false theory espoused by a fringe of extremists. Most of XX century science is direct evidence against Y. E. C. Entire books have been devoted to explain how the universe formed and what we currently, rationally and reasonably think might have happened and why. Any pop-sci book on cosmology, physics, evolution would be an interesting read. Here is a diagram illustrating the consequences (and therefore, the amount of dependent evidence that needs to be disproofed as part of accepting a young Earth). Entire physical sciences need to be proven totally wrong before Y. E. C. is acceptable If the Earth were young, it would imply that: All XX century physics is very wrong We have no clue about why chemistry works All modern biology is wrong We don't really understand modern medicine Paleontology ? Nope, all wrong. Geology ? Back to the XIX century as well Direct proof All these sciences are based on hard , indisputable and verifiable facts and they either depend on Earth being billions of years old, or they predict that it is. This is a graph of the results of lead dating Earth through radioactive dating experiments: Other dating results are summarized on wikipedia (relevant citation is in a book): Statistics for several meteorites that have undergone isochron dating are as follows: St. Severin (ordinary chondrite)
Pb-Pb isochron - 4.543 +/- 0.019 GY
Sm-Nd isochron - 4.55 +/- 0.33 GY
Rb-Sr isochron - 4.51 +/- 0.15 GY
Re-Os isochron - 4.68 +/- 0.15 GY
Juvinas (basaltic achondrite)
Pb-Pb isochron ..... 4.556 +/- 0.012 GY
Pb-Pb isochron ..... 4.540 +/- 0.001 GY
Sm-Nd isochron ..... 4.56 +/- 0.08 GY
Rb-Sr isochron ..... 4.50 +/- 0.07 GY
Allende (carbonaceous chondrite)
Pb-Pb isochron ..... 4.553 +/- 0.004 GY
Ar-Ar age spectrum ..... 4.52 +/- 0.02 GY
Ar-Ar age spectrum ..... 4.55 +/- 0.03 GY
Ar-Ar age spectrum ..... 4.56 +/- 0.05 GY Source: Dalrymple, Brent G. (2004). Ancient Earth, Ancient Skies: The Age of the Earth and Its Cosmic Surroundings. Stanford University Press. pp. 147, 169. ISBN 978-0804749336. | {
"source": [
"https://skeptics.stackexchange.com/questions/1438",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/49/"
]
} |
1,450 | With my limited knowledge of the process of nuclear fusion energy, this seems like one of the most promising methods for producing huge amounts of energy, with relatively very low risk, once researchers manage to control the process. The claim goes that the nuclear waste of nuclear fusion is negligible and that the process of generating nuclear fusion energy is easily containable, contrary to nuclear fission energy. However, are there any significant risks involved I may not be aware of yet? | All proposed methods of power generation using nuclear fusion will be safer than current methods using nuclear fission (assuming any of the proposed methods actually work). Note: Fusion reactors will not use the H1 + H1 reaction that powers the Sun (see: proton–proton chain reaction ) * . The current designs combine (fuse) some combination of isotopes of hydrogen: deuterium , or tritium . Safety issues are largely dependent how those elements are combined (see: fusion fuel cycle ). Some of the basic safety issues... Possibily of "meltdown": Continuous operation of the plant is
maintained by continual refuelling
with the fuel mixture (deuterium and
tritium), so the fuel inventory in the
plasma chamber at any time is
sufficient only for about one minute
of operation. -- source Production of radioactive waste: Nearly all materials become activated
to some degree by energetic neutron
bombardment. Neutron reactions in DT
fusion reactors will inevitably create
radioisotopes. The principal
radioactive materials present in a DT
fusion reactor will therefore be
tritium and neutron activated
structural materials surrounding the
reaction volume. -- source Release of tritium: (as noted this would not be a concern in a deuterium-deuterium process) There are also other concerns,
principally regarding the possible
release of tritium into the
environment. It is radioactive and
very difficult to contain since it can
penetrate concrete, rubber and some
grades of steel...snip...Each fusion
reactor could release significant
quantities of tritium during operation
through routine leaks, assuming the
best containment systems. An accident
could release even more. This is one
reason why long-term hopes are for the
deuterium-deuterium fusion process,
dispensing with tritium. -- source More sources of information: Safety and Environmental Impact of Fusion Tritium Hazard Report: Pollution and Radiation Risk from Canadian Nuclear Facilities Review of the Greenpeace report: "Tritium Hazard Report: Pollution and Radiation Risk from Canadian Nuclear Facilities" The Wikipedia entry Fusion Power also is a reasonable source for the basics and further research. * At the temperatures and densities in stellar cores the rates of fusion reactions are notoriously slow. For example, at solar core temperature (T ≈ 15 MK) and density (160 g/cm³), the energy release rate is only 276 μW/cm³—about a quarter of the volumetric rate at which a resting human body generates heat. (see: Astrophysical reaction chains ) | {
"source": [
"https://skeptics.stackexchange.com/questions/1450",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/1170/"
]
} |
1,499 | People like to claim that less developed countries are happier, because they live the simple life and stronger family ties. We've all heard the saying: Money can't buy you happiness. Which is easy to dismiss by showing that rich nations do better on the satisfaction of life index than poor ones (yes, correlation does not imply causation, but I'm fairly sure there's a causal link in this case). I'm curious though if it's always the case that increased wealth leads to a negative impact on happiness, even after an adjustment period. Can a case be made that: Money can't buy (society) happiness (sometimes). Where increase in money is the primary cause. | In High income improves evaluation of life but not emotional well-being , the authors make the distinction between two factors aspects to happiness and then evaluate each aspect's relation with income. The first one is emotional well-being , which they define as: Emotional well-being (sometimes called hedonic well-being or experienced happiness) refers to the emotional quality of an individual’s everyday experience—the frequency and intensity of experiences of joy, fascination, anxiety, sadness, anger, and affection
that make one’s life pleasant or unpleasant. The second is life evaluation : Life evaluation refers to a person’s thoughts about his or her life. Additionally, they also measured what they called "blue effect," which the "average of worry and sadness," and "positive effect," which is defined "by the average of three dichotomous items (reports of happiness, enjoyment, and frequent smiling and laughter)." After evaluating the results of the 2008 and 2009 Gallup-Healthways Well-Being Index, the authors found that emotional well-being correlates with income, up to an an annual income of $75,000, after which point it has. They also found that both positive effect and blue effect correlates with income (positive effect positively and blue effects negatively), also only up to a certain point. On the other hand,m life evaluation correlated strongly with education and income. In light of those results, they conclude that (emphasis mine): The data for positive and blue affect provide an unexpectedly sharp answer to our original question. More money does not necessarily buy more happiness, but less money is associated with emotional pain. Perhaps $75,000 is a threshold beyond which further increases in income no longer improve individuals’ ability to do what matters most to their emotional well-being, such as spending time with people they like, avoiding pain and disease, and enjoying leisure. Considering that wealth reduces sadness and worry, it's unlikely that an increase in wealth would result is a loss of happiness, unless wealth comes with an associated cost (sickness, for example). Wealth alone, however, does not seem to cause unhappiness. If you require a more global look at the problem, there is Wealth and happiness across the world: material prosperity predicts life evaluation, whereas psychosocial prosperity predicts positive feeling. , a review of the Gallup World Poll, which "was used to explore the reasons why happiness is associated with higher income." It finds that income only has a minor impact on emotional well-being, and that it is psychological needs that affects one's emotional well-being (emphasis mine, again): Income was a moderately strong predictor of life evaluation but a much weaker predictor of positive and negative feelings. Possessing luxury conveniences and satisfaction with standard of living were also strong predictors of life evaluation. Although the meeting of basic and psychological needs mediated the effects of income on life evaluation to some degree, the strongest mediation was provided by standard of living and ownership of conveniences. In contrast, feelings were most associated with the fulfillment of psychological needs: learning, autonomy, using one's skills, respect, and the ability to count on others in an emergency. Thus, two separate types of prosperity - economic and social psychological - best predict different types of well-being. In any case, neither studies found a negative correlation between wealth and happiness. | {
"source": [
"https://skeptics.stackexchange.com/questions/1499",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/631/"
]
} |
1,508 | I'm sure most of us have heard at least a variation of this myth. Unfortunately I failed to find the original source. Was there actually a study that claimed this? A lot of the sites debunking this myth point to the book "The Social Organization of Sexuality: Sexual Practices in the United States" citing: 54% of men think about sex everyday, or several times a day, 43% think about sex a few times per month, or a few times per week 4% think about sex less than once a month. These numbers show that almost half the men don't even think about sex once a day . But that book is from 1994 and from what I understand it was just a survey. In 2006 Dr. Louann Brizendine published her book The Female Brain , in which see apparently claims : Studies have shown that while a man
will think about sex every 52 seconds ,
the subject tends to cross women's
minds just once a day. I don't have the book, so I don't know which studies she is referencing. Are there actually studies (not just polls ) that show men think about sex fairly often? | Finally, someone has done a study that will provide an answer. The study, run by Dr Terri Fisher , asked 163 students to carry a tally counter, and note when they had thoughts about sex: It won't be published until January 2012 so I have had to rely on early press reports, such as this one in MedicalXpress : the research discredits the persistent stereotype that men think about sex every seven seconds , which would amount to more than 8,000 thoughts about sex in 16 waking hours. In the study, the median number of young men's thought about sex stood at almost 19 times per day. Young women in the study reported a median of nearly 10 thoughts about sex per day. [...] Correcting this stereotype about men's sexual thoughts is important, Fisher noted.
"It's amazing the way people will spout off these fake statistics that men think about sex nearly constantly and so much more often than women do," she said. "When a man hears a statement like that, he might think there's something wrong with him because he's not spending that much time thinking about sexuality, and when women hear about this, if they spend significant time thinking about sex they might think there's something wrong with them." It's hard to properly evaluate the methodology and results before seeing it published; press reports are often inaccurate. One aspect that concerns me is that it required student to notice that they were having these thoughts. Perhaps a better methodology would be a buzzer that rang randomly, and had the students record whether they were thinking about sex at the time, would have gotten better results. Obviously, self-reporting about a taboo topic is another issue. Update: The article was published: Fisher TD, Moore ZT, Pittenger MJ., Sex on the brain?: an examination of frequency of sexual cognitions as a function of gender, erotophilia, and social desirability. J Sex Res. 2012;49(1):69-77. doi: 10.1080/00224499.2011.565429. I see nothing in the abstract or first couple of pages which undermines any of the above analysis. | {
"source": [
"https://skeptics.stackexchange.com/questions/1508",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/454/"
]
} |
1,509 | Possible Duplicate: Is being a vegan more environmentally friendly than otherwise? Would it be sufficient for people to stop eating meat to stop global warming? I've heard that the process to bring meat to everyone's plate is one of the biggest contributors to greenhouse emissions. This include the feeding of the animals, the cooling of the meat, transport, etc. | The meat industry is indeed a major contributor to global warming, and other environmental effects such as deforestation. However, it does not seem that stopping eating meat by itself is enough to stop global warming. In Diet, Energy, and Global Warming by Gidon Eshel and Pamela A. Martin, the authors claim that moving from meat-based diet to a vegetarian diet saves about 6% of the greenhouse gas emissions: Conclusions We examine the greenhouse gas emissions associated with plant- and animal-based diets, considering both direct and indirect emissions (i.e., CO 2 emissions due to fossil fuel combustion, and methane and nitrous oxide CO 2 -equivalent emissions due to animal-based food production). We conclude that a person consuming a mixed diet with the mean American caloric content and composition causes the emissions of 1485 kg CO 2 -equivalent above the emissions associated with consuming the same number of calories, but from plant sources. Far from trivial, nationally this difference amounts to over 6% of the total U.S. greenhouse gas emissions. We conclude by briefly addressing the public health safety of plant-based diets, and find no evidence for adverse effects. Note that this study is based on US data - the effect would be smaller in places where current diet already includes less meat. I don't know what level of CO 2 emission reduction is needed to stop global warming. but the change of green house gas concentration between the beginning of the industrial revolution and today is about 40% ( data from US Department of Energy ) - much more than what will be saved from stopping the meat industry. This is a lot, but it doesn't appear enough. Based on Target atmospheric CO2: Where should humanity aim? A level of 350 PPM of CO 2 is desired to stop global warming, while the current level is 385 PPM - a difference of about 8%. This is much closer to the amount reached by the Diet, Energy, and Global Warming paper, but a similar study that takes into account global (and not just US) data is needed to get a real conclusion. | {
"source": [
"https://skeptics.stackexchange.com/questions/1509",
"https://skeptics.stackexchange.com",
"https://skeptics.stackexchange.com/users/873/"
]
} |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.