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Both McLuhan and Innis assume the centrality of communication technology ; where they differ is in the principal kinds of effects they see deriving from this technology . Whereas Innis sees communication technology principally affecting social organization and culture , McLuhan sees its principal effect on sensory organization and thought . McLuhan has much to say about perception and thought but little to say about institutions ; Innis says much about institutions and little about perception and thought . |
Biographer John Watson notes that Innis 's work was profoundly political while McLuhan 's was not . He writes that " the mechanization of knowledge , not the relative sensual bias of media , is the key to Innis 's work . This also underlies the politicization of Innis 's position vis @-@ a @-@ vis that of McLuhan . " Watson adds that Innis believed very different media could produce similar effects . " For Innis , the yellow press of the United States and the Nazi loudspeaker had the same form of negative effect : they reduced men from thinking beings to mere automatons in a chain of command . " Watson argues that while McLuhan separated media according to their sensory bias , Innis examined a different set of interrelationships , the " dialectic of power and knowledge " in specific historical circumstances . For Watson , Innis 's work is therefore more flexible and less deterministic than McLuhan 's . |
As scholars and teachers , Innis and McLuhan shared a similar dilemma since both argued that book culture tended to produce fixed points of view and homogeneity of thought ; yet both produced many books . In his introduction to the 1964 reprint of The Bias of Communication , McLuhan marvelled at Innis 's technique of juxtaposing " his insights in a mosaic structure of seemingly unrelated and disproportioned sentences and aphorisms " . McLuhan argued that although this made reading Innis 's dense prose difficult — " a pattern of insights that are not packaged for the consumer palate " — Innis 's method approximated " the natural form of conversation or dialogue rather than of written discourse " . Best of all , it yielded " insight " and " pattern recognition " rather than the " classified knowledge " so overvalued by print @-@ trained scholars . " How exciting it was to encounter a writer whose every phrase invited prolonged meditation and exploration " , McLuhan added . McLuhan 's own books with their reliance on aphorisms , puns , quips , " probes " and oddly juxtaposed observations also employ this mosaic technique . |
Innis 's theories of political economy , media and society remain highly relevant : he had a profound influence on critical media theory and communications and , in conjunction with McLuhan , offered groundbreaking Canadian perspectives on the function of communication technologies as key agents in social and historical change . Together , their works advanced a theory of history in which communication is central to social change and transformation . |
= Hurricane Lorenzo ( 2007 ) = |
Hurricane Lorenzo was a rapidly developing tropical cyclone that struck the Mexican state of Veracruz in late September 2007 . The twelfth named storm and fifth hurricane of the 2007 Atlantic hurricane season , it formed in the southwestern Gulf of Mexico from a tropical wave . After meandering for two days without development , the storm began a steady westward track as its structure became better organized . In an 18 ‑ hour period , Lorenzo 's winds increased from 35 mph ( 55 km / h ) to 80 mph ( 130 km / h ) , or from a tropical depression to a hurricane . On September 28 it struck near Tecolutla , Veracruz , a month after Hurricane Dean affected the same area , before it quickly dissipated over land . |
The most significantly affected area was Veracruz , where damage reached over $ 1 billion pesos ( $ 92 million 2007 USD ) . Most of it came from road damage in the state 's northern portion , although there were also hundreds of damaged houses . Between Veracruz and neighboring Hidalgo , there were 123 @,@ 320 people affected across 112 municipalities . Overall there were six deaths in the country , one in Veracruz and five in Puebla . In the latter state , a family of three perished in a landslide . |
= = Meteorological history = = |
The origins of Hurricane Lorenzo were from a tropical wave that exited the coast of Africa on September 11 . After moving across the tropical Atlantic Ocean , it traversed much of the Caribbean Sea before developing an area of thunderstorms on September 21 . The system developed a low pressure area on September 23 after the northern portion of the wave broke off and crossed the Yucatán Peninsula . Initially , a Hurricane Hunters flight was scheduled to investigate the system , although the low became disorganized over the southeastern Gulf of Mexico due to high wind shear . However , the wind shear decreased , and late on September 25 , another Hurricane Hunters flight indicated the development of a closed low @-@ level circulation . Based on that observation , along with sufficient persistence of the thunderstorms , the system developed into Tropical Depression Thirteen about 190 mi ( 305 km ) east of Tampico , Tamaulipas . |
Upon developing , the depression was located in an area of weak steering currents , resulting in an erratic movement generally to the south . In its formative stages , the depression executed a small loop . As it did so , it moved into an area of very warm waters and decreasing wind shear . The depression 's convection gradually organized , although the winds were slower to increase . An anticyclone became established over the system , and the depression intensified into Tropical Storm Lorenzo at around 1200 UTC on September 27 . At the time , it was located about 150 mi ( 240 km ) east of Tuxpan , Veracruz , moving steadily westward under the influence of a building ridge to its east . As it approached the coast , Lorenzo rapidly intensified unexpectedly , and within 12 hours of attaining tropical storm status it strengthened into a hurricane . |
Hurricane Lorenzo quickly developed a closed eyewall , which was observed on radar and provided a peak intensity estimate of 80 mph ( 130 km / h ) at 0000 UTC on September 28 . The cyclone maintained vigorous and symmetric convection across the center , although the structure deteriorated slightly before Lorenzo crossed the coast near Tecolutla , Veracruz at 0500 UTC that day , with winds estimated around 75 mph ( 120 km / h ) . After making landfall , the hurricane rapidly weakened to tropical depression intensity . Progressing inland , the circulation became difficult to locate as the convection diminished to rainbands along the coast . Within 19 hours after moving ashore , the circulation of Lorenzo dissipated , therefore ending its duration as a tropical cyclone . |
= = Preparations and impact = = |
About 26 hours before landfall , the Mexican government issued a tropical storm watch from Palma Sola to La Cruz in Veracruz . About 14 hours before landfall , a tropical storm warning was put into place from Palma Sola to Cabo Rojo , which in turn was upgraded to a hurricane warning six hours later . Mexico 's Civilian Protection officials declared a " red alert " for much of the state of Veracruz . Along the coast of Veracruz , officials canceled school classes . Officials opened 315 shelters in Veracruz , along with six in neighboring Hidalgo , which housed 45 @,@ 164 people during the storm . The government of Veracruz provided buses for people to transport from their houses to the shelters . Ports in Tecolutla , Tuxpan and Nautla were forced to close . Lorenzo 's formation caused gas prices to rise due to its potential to disrupt oil facilities in the Gulf of Mexico . |
Hurricane Lorenzo made landfall in Veracruz , the same region of east @-@ central Mexico as Hurricane Dean did one month prior . The hurricane primarily affected small fishing villages along the coast , where strong winds knocked down power lines , leaving about 85 @,@ 000 people without electricity . To prevent the danger of fallen wires , officials shut off the power grid in several municipalities in northern Veracruz . The winds also destroyed the roofs of several houses in Nautla . In addition to the high winds , Lorenzo dropped heavy rainfall along the coast and further inland , peaking at 12 @.@ 83 in ( 326 mm ) in El Raudal , Veracruz . The rains caused flash flooding and mudslides that killed at least four people , including a family of three in Puebla state . Landslides also closed portions of three highways . In some locations , floodwaters reached about 1 foot ( 300 mm ) in depth . The combination of winds and rains damaged 169 houses in Puebla , while in Hidalgo , the San Lorenzo River overflowed its banks and forced the evacuation of over 200 people . Overflown rivers in Veracruz forced about 25 @,@ 000 people to leave their houses . Along the Cazones River , more than 1 @,@ 000 houses were flooded , resulting in local police officials to assist in evacuations . Damage in Veracruz was estimated at $ 1 billion pesos ( $ 92 million 2007 USD ) , much of it from road damage in the northern portion of the state . |
Overall , the hurricane affected 123 @,@ 320 people across Veracruz and Hidalgo , prompting the declaration of a state of emergency in 112 municipalities . The declaration allowed the usage of emergency resources for the affected people . There were a total of six deaths in the country , five of which in Puebla . By about three days after the storm , all schools were reopened . The Mexican government distributed food , water , and construction materials for the areas most affected in Veracruz . Following the storm , about 500 power workers were dispatched in Veracruz to restore electricity in the affected areas . |
= Cadmium = |
Cadmium is a chemical element with symbol Cd and atomic number 48 . This soft , bluish @-@ white metal is chemically similar to the two other stable metals in group 12 , zinc and mercury . Like zinc , it demonstrates oxidation state + 2 in most of its compounds , and like mercury , it has a lower melting point than other transition metals . Cadmium and its congeners are not always considered transition metals , in that they do not have partly filled d or f electron shells in the elemental or common oxidation states . The average concentration of cadmium in Earth 's crust is between 0 @.@ 1 and 0 @.@ 5 parts per million ( ppm ) . It was discovered in 1817 simultaneously by Stromeyer and Hermann , both in Germany , as an impurity in zinc carbonate . |
Cadmium occurs as a minor component in most zinc ores and is a byproduct of zinc production . Cadmium was used for a long time as a corrosion @-@ resistant plating on steel , and cadmium compounds are used as red , orange and yellow pigments , to colour glass , and to stabilize plastic . Cadmium use is generally decreasing because it is toxic ( it is specifically listed in the European Restriction of Hazardous Substances ) and nickel @-@ cadmium batteries have been replaced with nickel @-@ metal hydride and lithium @-@ ion batteries . One of its few new uses is cadmium telluride solar panels . |
Although cadmium has no known biological function in higher organisms , a cadmium @-@ dependent carbonic anhydrase has been found in marine diatoms . |
= = Characteristics = = |
= = = Physical properties = = = |
Cadmium is a soft , malleable , ductile , bluish @-@ white divalent metal . It is similar in many respects to zinc but forms complex compounds . Unlike most other metals , cadmium is resistant to corrosion and is used as a protective plate on other metals . As a bulk metal , cadmium is insoluble in water and is not flammable ; however , in its powdered form it may burn and release toxic fumes . |
= = = Chemical properties = = = |
Although cadmium usually has an oxidation state of + 2 , it also exists in the + 1 state . Cadmium and its congeners are not always considered transition metals , in that they do not have partly filled d or f electron shells in the elemental or common oxidation states . Cadmium burns in air to form brown amorphous cadmium oxide ( CdO ) ; the crystalline form of this compound is a dark red which changes color when heated , similar to zinc oxide . Hydrochloric acid , sulfuric acid , and nitric acid dissolve cadmium by forming cadmium chloride ( CdCl2 ) , cadmium sulfate ( CdSO4 ) , or cadmium nitrate ( Cd ( NO3 ) 2 ) . The oxidation state + 1 can be produced by dissolving cadmium in a mixture of cadmium chloride and aluminium chloride , forming the Cd22 + cation , which is similar to the Hg22 + cation in mercury ( I ) chloride . |
Cd + CdCl2 + 2 AlCl3 → Cd2 ( AlCl4 ) 2 |
The structures of many cadmium complexes with nucleobases , amino acids , and vitamins have been determined . |
= = = Isotopes = = = |
Naturally occurring cadmium is composed of 8 isotopes . Two of them are radioactive , and three are expected to decay but have not done so under laboratory conditions . The two natural radioactive isotopes are 113Cd ( beta decay , half @-@ life is 7 @.@ 7 × 1015 years ) and 116Cd ( two @-@ neutrino double beta decay , half @-@ life is 2 @.@ 9 × 1019 years ) . The other three are 106Cd , 108Cd ( both double electron capture ) , and 114Cd ( double beta decay ) ; only lower limits on these half @-@ lives have been determined . At least three isotopes – 110Cd , 111Cd , and 112Cd – are stable . Among the isotopes that do not occur naturally , the most long @-@ lived are 109Cd with a half @-@ life of 462 @.@ 6 days , and 115Cd with a half @-@ life of 53 @.@ 46 hours . All of the remaining radioactive isotopes have half @-@ lives of less than 2 @.@ 5 hours , and the majority have half @-@ lives of less than 5 minutes . Cadmium has 8 known meta states , with the most stable being 113mCd ( t1 / 2 |
= 14 @.@ 1 years ) , 115mCd ( t1 / 2 = |
44 @.@ 6 days ) , and 117mCd ( t1 / 2 = 3 @.@ 36 hours ) . |
The known isotopes of cadmium range in atomic mass from 94 @.@ 950 u ( 95Cd ) to 131 @.@ 946 u ( 132Cd ) . For isotopes lighter than 112 u , the primary decay mode is electron capture and the dominant decay product is element 47 ( silver ) . Heavier isotopes decay mostly through beta emission producing element 49 ( indium ) . |
One isotope of cadmium , 113Cd , absorbs neutrons with high selectivity : With very high probability , neutrons with energy below the cadmium cut @-@ off will be absorbed ; those higher than the cut @-@ off will be transmitted . The cadmium cut @-@ off is about 0 @.@ 5 eV , and neutrons below that level are deemed slow neutrons , distinct from intermediate and fast neutrons . |
Cadmium is created via the long s @-@ process in low @-@ medium mass stars with masses of 0 @.@ 6 to 10 solar masses , taking thousands of years . In that process , a silver atom captures a neutron and then undergoes beta decay . |
= = History = = |
Cadmium ( Latin cadmia , Greek καδμεία meaning " calamine " , a cadmium @-@ bearing mixture of minerals that was named after the Greek mythological character Κάδμος , Cadmus , the founder of Thebes ) was discovered simultaneously in 1817 by Friedrich Stromeyer and Karl Samuel Leberecht Hermann , both in Germany , as an impurity in zinc carbonate . Stromeyer found the new element as an impurity in zinc carbonate ( calamine ) , and , for 100 years , Germany remained the only important producer of the metal . The metal was named after the Latin word for calamine , because it was found in this zinc compound . Stromeyer noted that some impure samples of calamine changed color when heated but pure calamine did not . He was persistent in studying these results and eventually isolated cadmium metal by roasting and reducing the sulfide . The potential for cadmium yellow as pigment was recognized in the 1840s , but the lack of cadmium limited this application . |
Even though cadmium and its compounds are toxic in certain forms and concentrations , the British Pharmaceutical Codex from 1907 states that cadmium iodide was used as a medication to treat " enlarged joints , scrofulous glands , and chilblains " . |
In 1907 , the International Astronomical Union defined the international ångström in terms of a red cadmium spectral line ( 1 wavelength = 6438 @.@ 46963 Å ) . This was adopted by the 7th General Conference on Weights and Measures in 1927 . In 1960 , the definitions of both the metre and ångström were changed to use krypton . |
After the industrial scale production of cadmium started in the 1930s and 1940s , the major application of cadmium was the coating of iron and steel to prevent corrosion ; in 1944 , 62 % and in 1956 , 59 % of the cadmium in the United States was used for plating . In 1956 , 24 % of the cadmium in the United States was used for a second application in red , orange and yellow pigments from sulfides and selenides of cadmium . |
The stabilizing effect of cadmium chemicals like the carboxylates cadmium laurate and cadmium stearate on PVC led to an increased use of those compounds in the 1970s and 1980s . The demand for cadmium in pigments , coatings , stabilizers , and alloys declined as a result of environmental and health regulations in the 1980s and 1990s ; in 2006 , only 7 % of to total cadmium consumption was used for plating , and only 10 % was used for pigments . At the same time , these decreases in consumption were compensated by a growing demand for cadmium for nickel @-@ cadmium batteries , which accounted for 81 % of the cadmium consumption in the United States in 2006 . |
= = Occurrence = = |
Cadmium makes up about 0 @.@ 1 mg kg − 1 ( ppm ) of Earth 's crust . Typical background concentrations in other environmental media are : atmosphere < 5 ng m − 3 ; soil < 2 mg kg − 1 ; vegetation < 0 @.@ 5 mg kg − 1 ; freshwater < 1 ug L − 1 ; seawater < 50 ng L − 1 ; sediment < 2 mg kg − 1 . Compared with the more abundant 65 ppm zinc , cadmium is rare . No significant deposits of cadmium @-@ containing ores are known . Greenockite ( CdS ) , the only cadmium mineral of importance , is nearly always associated with sphalerite ( ZnS ) . This association is caused by geochemical similarity between zinc and cadmium , with no geological process likely to separate them . Thus , cadmium is produced mainly as a byproduct from mining , smelting , and refining sulfidic ores of zinc , and , to a lesser degree , lead and copper . Small amounts of cadmium , about 10 % of consumption , are produced from secondary sources , mainly from dust generated by recycling iron and steel scrap . Production in the United States began in 1907 , but not until after World War I did cadmium come into wide use . |
Metallic cadmium can be found is the Vilyuy River basin in Siberia . |
Rocks mined for phosphate fertilizers contain varying amounts of cadmium , resulting in a cadmium concentration of as much as 300 mg / kg in the fertilizers and a high cadmium content in agricultural soils . Coal can contain significant amounts of cadmium , which ends up mostly in flue dust . |
= = Production = = |
The British Geological Survey reports that in 2001 , China was the top producer of cadmium with almost one @-@ sixth of the world 's production , closely followed by South Korea and Japan . |
Cadmium is a common impurity in zinc ores , and it is most often isolated during the production of zinc . Some zinc ores concentrates from sulfidic zinc ores contain up to 1 @.@ 4 % of cadmium . In the 1970s , the output of cadmium was 6 @.@ 5 pounds per ton of zinc . Zinc sulfide ores are roasted in the presence of oxygen , converting the zinc sulfide to the oxide . Zinc metal is produced either by smelting the oxide with carbon or by electrolysis in sulfuric acid . Cadmium is isolated from the zinc metal by vacuum distillation if the zinc is smelted , or cadmium sulfate is precipitated from the electrolysis solution . |
= = Applications = = |
Cadmium is a common component of electric batteries , pigments , coatings , and electroplating . |
= = = Batteries = = = |
In 2009 , 86 % of cadmium was used in batteries , predominantly in rechargeable nickel @-@ cadmium batteries . Nickel @-@ cadmium cells have a nominal cell potential of 1 @.@ 2 V. The cell consists of a positive nickel hydroxide electrode and a negative cadmium electrode plate separated by an alkaline electrolyte ( potassium hydroxide ) . The European Union put a limit on cadmium in electronics in 2004 of 0 @.@ 01 % , with some exceptions , and reduced the limit on cadmium content to 0 @.@ 002 % . |
= = = Electroplating = = = |
Cadmium electroplating , consuming 6 % of the global production , is used in the aircraft industry reduce corrosion of steel components . This coating is passivated by chromate salts . A limitation of cadmium plating is hydrogen embrittlement of high @-@ strength steels from the electroplating process . Therefore , steel parts heat @-@ treated to tensile strength above 1300 MPa ( 200 ksi ) should be coated by an alternative method ( such as special low @-@ embrittlement cadmium electroplating processes or physical vapor deposition ) . |
Titanium embrittlement from cadmium @-@ plated tool residues resulted in banishment of those tools ( and the implementation of routine tool testing to detect cadmium contamination ) in the A @-@ 12 / SR @-@ 71 , U @-@ 2 , and subsequent aircraft programs that use titanium . |
= = = Nuclear fission = = = |
Cadmium is used in the control rods of nuclear reactors , acting as a very effective " neutron poison " to control neutron flux in nuclear fission . When cadmium rods are inserted in the core of a nuclear reactor , cadmium absorbs neutrons preventing them from creating additional fission events , thus controlling the amount of reactivity . The pressurized water reactor designed by Westinghouse Electric Company uses an alloy consisting of 80 % silver , 15 % indium , and 5 % cadmium . |
= = = Compounds = = = |
Cadmium oxide was used in black and white television phosphors and in the blue and green phosphors of color television cathode ray tubes . Cadmium sulfide ( CdS ) is used as a photoconductive surface coating for photocopier drums . |
Various cadmium salts are used in paint pigments , with CdS as a yellow pigment being the most common . Cadmium selenide is a red pigment , commonly called cadmium red . To painters who work with the pigment , cadmium provides the most brilliant and durable yellows , oranges , and reds — so much so that during production , these colors are significantly toned down before they are ground with oils and binders or blended into watercolors , gouaches , acrylics , and other paint and pigment formulations . Because these pigments are potentially toxic , users should use a barrier cream on the hands to prevent absorption through the skin even though the amount of cadmium absorbed into the body through the skin is reported to be less than 1 % . |
In PVC , cadmium was used as heat , light , and weathering stabilizers . Currently , cadmium stabilizers have been completely replaced with barium @-@ zinc , calcium @-@ zinc and organo @-@ tin stabilizers . Cadmium is used in many kinds of solder and bearing alloys , because a low coefficient of friction and fatigue resistance . It is also found in some of the lowest @-@ melting alloys , such as Wood 's metal . |
= = = Laboratory uses = = = |
Helium – cadmium lasers are a common source of blue @-@ ultraviolet laser light . They operate at either 325 or 422 nm in fluorescence microscopes and various laboratory experiments . Cadmium selenide quantum dots emit bright luminescence under UV excitation ( He @-@ Cd laser , for example ) . The color of this luminescence can be green , yellow or red depending on the particle size . Colloidal solutions of those particles are used for imaging of biological tissues and solutions with a fluorescence microscope . |
Cadmium is a component of some compound semiconductors , such as cadmium sulfide , cadmium selenide , and cadmium telluride , used for light detection and solar cells . HgCdTe is sensitive to infrared light and can be used as an infrared detector , motion detector , or switch in remote control devices . |
In molecular biology , cadmium is used to block voltage @-@ dependent calcium channels from fluxing calcium ions , as well as in hypoxia research to stimulate proteasome @-@ dependent degradation of Hif @-@ 1α . |
= = = Cadmium @-@ selective sensors = = = |
Cadmium @-@ selective sensors based on the fluorophore BODIPY have been developed for imaging and sensing of cadmium in cells . |
= = Biological role = = |
Cadmium has no known function in higher organisms , but a cadmium @-@ dependent carbonic anhydrase has been found in some marine diatoms . The diatoms live in environments with very low zinc concentrations and cadmium performs the function normally carried out by zinc in other anhydrases . This was discovered with X @-@ ray absorption fluorescence spectroscopy ( XAFS ) . |
The highest concentration of cadmium is absorbed in the kidneys of humans , and up to about 30 mg of cadmium is commonly inhaled throughout human childhood and adolescence . |
Cadmium can be used to block calcium channels in chicken neurons . Analytical methods for the determination of cadmium in biological samples have been reviewed . |
= = Environment = = |
The biogeochemistry of cadmium and its release to the environment has been the subject of review , as has the speciation of cadmium in the environment . |
Environmental concentrations can exceed adverse @-@ effect @-@ thresholds in cadmium @-@ polluted ecosystems ( e.g. in some parts of Europe ) and pollutant cadmium can accumulate in invertebrates , earthworms , seabirds , marine mammals , plants , and some algal species ; effects in animals include kidney disorders , impairment of enzymes , disruption of calcium metabolism , and changes in cell membrane permeability ; excess Cd uptake in plants can affect growth and metabolic processes such as photosynthesis and transpiration . |
= = Safety = = |
The bioinorganic aspects of cadmium toxicity have been reviewed . |
The most dangerous form of occupational exposure to cadmium is inhalation of fine dust and fumes , or ingestion of highly soluble cadmium compounds . Inhalation of cadmium fumes can result initially in metal fume fever but may progress to chemical pneumonitis , pulmonary edema , and death . |
Cadmium is also an environmental hazard . Human exposure is primarily from fossil fuel combustion , phosphate fertilizers , natural sources , iron and steel production , cement production and related activities , nonferrous metals production , and municipal solid waste incineration . Bread , root crops , and vegetables also contribute to the cadmium in modern populations . |
There have been a few instances of general population poisoning as the result of long @-@ term exposure to cadmium in contaminated food and water , and research into an estrogen mimicry that may induce breast cancer is ongoing . In the decades leading up to World War II , mining operations contaminated the Jinzū River in Japan with cadmium and traces of other toxic metals . As a consequence , cadmium accumulated in the rice crops along the riverbanks downstream of the mines . Some members of the local agricultural communities consumed the contaminated rice and developed itai @-@ itai disease and renal abnormalities , including proteinuria and glucosuria . |
The victims of this poisoning were almost exclusively post @-@ menopausal women with low iron and other mineral body stores . Similar general population cadmium exposures in other parts of the world have not resulted in the same health problems because the populations maintained sufficient iron and other mineral levels . Thus , although cadmium is a major factor in the itai @-@ itai disease in Japan , most researchers have concluded that it was one of several factors . Cadmium is one of six substances banned by the European Union 's Restriction on Hazardous Substances ( RoHS ) directive , which regulates hazardous substances in electrical and electronic equipment but allows for certain exemptions and exclusions from the scope of the law . The International Agency for Research on Cancer has classified cadmium and cadmium compounds as carcinogenic to humans . Although occupational exposure to cadmium is linked to lung and prostate cancer , there is still a substantial controversy about the carcinogenicity of cadmium in low environmental exposure . Recent data from epidemiological studies suggest that intake of cadmium through diet associates to higher risk of endometrial , breast and prostate cancer as well as to osteoporosis in humans . A recent study has demonstrated that endometrial tissue is characterized by higher levels of cadmium in current and former smoking females . |
Cadmium exposure is a risk factor associated with a large number of illnesses including kidney disease , early atherosclerosis , hypertension , and cardiovascular diseases . Although studies show a significant correlation between cadmium exposure and occurrence of disease in human populations , a necessary molecular mechanism has not been identified . One hypothesis holds that cadmium is an endocrine disruptor and some experimental studies have shown that it can interact with different hormonal signaling pathways . For example , cadmium can bind to the estrogen receptor alpha , and affect signal transduction along the estrogen and MAPK signaling pathways at low doses . |
Tobacco smoking is the most important single source of cadmium exposure in the general population . An estimated 10 % of the cadmium content of a cigarette is inhaled through smoking . Absorption of cadmium through the lungs is more effective than through the gut , and as much as 50 % of the cadmium inhaled in cigarette smoke may be absorbed . On average , cadmium concentrations in the blood of smokers is 4 times 5 times greater and in the kidney , 2 – 3 times greater than non @-@ smokers . Despite the high cadmium content in cigarette smoke , there seems to be little exposure to cadmium from passive smoking . |
In a non @-@ smoking population , food is the greatest source of exposure . High quantities of cadmium can be found in crustaceans , mollusks , offal , and algae products . However , grains , vegetables , and starchy roots and tubers are consumed in much greater quantity in the US , and are the source of the greatest dietary exposure . Most plants bio @-@ accumulate metal toxins like Cd , and when composted to form organic fertilizers yield a product which can often contain high amounts ( e.g. , over 0 @.@ 5 mg ) of metal toxins for every kilo of fertilizer . Fertilizers made from animal dung ( e.g. , cow dung ) or urban waste can contain similar amounts of Cd . The Cd added to the soil from fertilizers ( rock phosphates or organic fertilizers ) become bio @-@ available and toxic only if the soil pH is low ( i.e. , acidic soils ) . Zinc is chemically similar to cadmium and some evidence indicates the presence of Zn ions reduces cadmium toxicity . |
Zinc , Cu , Ca , and Fe ions , and selenium with vitamin C are used to treat Cd intoxication , though it is not easily reversed . |
= = = Regulations = = = |
Because of the adverse effects of cadmium on the environment and human health , the supply and use of cadmium is restricted in Europe under the REACH Regulation . |
The EFSA Panel on Contaminants in the Food Chain specifies that 2 @.@ 5 μg / kg body weight is a tolerable weekly intake for humans . The Joint FAO / WHO Expert Committee on Food Additives has declared 7 μg / kg bw to be the provisional tolerable weekly intake level . |
The US Occupational Safety and Health Administration ( OSHA ) has set the permissible exposure limit ( PEL ) for cadmium at a time @-@ weighted average ( TWA ) of 0 @.@ 005 ppm . The National Institute for Occupational Safety and Health ( NIOSH ) has not set a recommended exposure limit ( REL ) and has designated cadmium as a known human carcinogen . The IDLH ( immediately dangerous to life and health ) level for cadmium is 9 mg / m3 . |
= = = Product recalls = = = |
In May 2006 , a sale of the seats from Arsenal F.C. ' s old stadium , Highbury in London , England was cancelled when the seats were discovered to contain trace amounts of cadmium . Reports of high levels of cadmium use in children 's jewelry in 2010 led to a US Consumer Product Safety Commission investigation . The U.S. CPSC issued specific recall notices for cadmium content in jewelry sold by Claire 's and Wal @-@ Mart stores . |
In June 2010 , McDonald 's voluntarily recalled more than 12 million promotional " Shrek Forever After 3D " Collectable Drinking Glasses because of the cadmium levels in paint pigments on the glassware . The glasses were manufactured by Arc International , of Millville , NJ , USA . |
= First Battle of Maryang San = |
The First Battle of Maryang San ( 3 – 8 October 1951 ) , also known as the Defensive Battle of Maliangshan ( Chinese : 马良山防御战 ; pinyin : Mǎliáng Shān Fángyù Zhàn ) , was fought during the Korean War between United Nations ( UN ) forces — primarily Australian and British — and the Chinese communist People 's Volunteer Army . The fighting occurred during a limited UN offensive by US I Corps , codenamed Operation Commando . This offensive ultimately pushed the Chinese back from the Imjin River to the Jamestown Line and destroyed elements of four Chinese armies following heavy fighting . The much smaller battle at Maryang San took place over a five @-@ day period , and saw the 3rd Battalion , Royal Australian Regiment ( 3 RAR ) dislodge a numerically superior Chinese force from the tactically important Kowang @-@ San ( Hill 355 ) and Maryang San ( Hill 317 ) features , in conjunction with other units of the 1st Commonwealth Division . |
Using tactics first developed against the Japanese in New Guinea during the Second World War , the Australians gained the advantage of the high ground and assaulted the Chinese positions from unexpected directions . They then repelled repeated Chinese counterattacks aimed at re @-@ capturing Maryang San , with both sides suffering heavy casualties before the Australians were finally relieved by a British battalion . However , with the peace @-@ talks ongoing , these operations proved to be last actions in the war of manoeuvre , which had lasted the previous sixteen months . It was replaced by a static war characterised by fixed defences reminiscent of the Western Front in 1915 – 17 . A month later , the Chinese subsequently re @-@ captured Maryang San from the British during fierce fighting , and it was never re @-@ gained . Today , the battle is widely regarded as one of the Australian Army 's greatest accomplishments during the war . |
= = Background = = |
= = = Military situation = = = |
Following General of the Army Douglas MacArthur 's dismissal as Commander @-@ in @-@ Chief of UN forces in Korea , he was replaced by General Matthew B. Ridgway . Consequently , on 14 April 1951 , General James Van Fleet replaced Ridgway as commander of the US Eighth Army and the United Nations forces in Korea . The Chinese Spring Offensive during April and May 1951 ended in its defeat , while following two months of sporadic operations in mid @-@ June and August , the war entered a new phase , with Van Fleet returning to the offensive . In July the Kansas and Wyoming Lines were strengthened , while a limited offensive in the east @-@ central sector in mid @-@ August seized the high ground around the Punchbowl and Bloody Ridge during the Battle of Bloody Ridge . In September the offensive in this sector continued , targeting the next hill complex north of Bloody Ridge , known as Heartbreak Ridge . |
Meanwhile , the organisation of British Commonwealth ground forces fighting in Korea as part of the United Nations Command had undergone considerable change in the months following the battles of the Imjin River and Kapyong in late @-@ April 1951 . 3 RAR had been transferred from 27th British Infantry Brigade to the 28th British Commonwealth Brigade when that formation departed for Hong Kong . Meanwhile , after protracted negotiations between the governments of Australia , Britain , Canada , India , New Zealand and South Africa , agreement had been reached to establish an integrated formation with the aim of increasing the political significance of their contribution , as well as facilitating the solution of the logistic and operational problems faced by the various Commonwealth contingents . |
The 1st Commonwealth Division was formed on 28 July 1951 , with the division including the 25th Canadian , 28th British Commonwealth and 29th British infantry brigades under the command of Major General James Cassels , and was part of US I Corps . Since its formation , the division had occupied part of the west @-@ central sector of the UN line , approximately 48 kilometres ( 30 mi ) north of the capital Seoul . The 28th Brigade included three infantry battalions — the 1st Battalion , King 's Own Scottish Borderers ( 1 KOSB ) , 1st Battalion , King 's Shropshire Light Infantry ( 1 KSLI ) and the 3rd Battalion , Royal Australian Regiment — under the command of Brigadier George Taylor . During this period 3 RAR was commanded by Lieutenant Colonel Francis Hassett . Peace @-@ talks at Kaesong during July and September led to a lull in the fighting and 3 RAR undertook mainly defensive duties , helping to construct the defences of the Kansas Line south of the Imjin River , as well as conducting extensive patrolling on the northern side . The battalion also used the reduced operational tempo as an opportunity to train reinforcements . The period culminated in a limited , and largely unopposed , divisional advance 12 kilometres ( 7 @.@ 5 mi ) north of the Imjin to the Wyoming Line , codenamed Operation Minden , in September . |
= = Prelude = = |
= = = Opposing forces = = = |
In late @-@ September and early @-@ October — even while continuing the attack against Heartbreak Ridge — Van Fleet developed a plan for a limited offensive in the western section , known as Operation Commando , to advance 10 kilometres ( 6 @.@ 2 mi ) north of the 38th parallel , with the aim of pushing Chinese forces back and giving United Nations forces more leverage at the truce negotiations now occurring at Panmunjom . Operation Commando was scheduled for 3 – 5 October 1951 and the US I Corps commander , Lieutenant General John W. O 'Daniel , envisioned a concept of operations in which three of the corps ' four divisions would advance on a broad front in conjunction with US 25th Infantry Division on the left flank of the neighbouring US IX Corps , seizing a new defensive line known as the Jamestown Line . The divisions to be used in the advance included the 1st Commonwealth Division , US 1st Cavalry Division and the 9th South Korean Division . The 1st South Korean Division would remain in its existing position on the left flank . |
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