Water pollution is the contamination of water bodies such as lakes, rivers, oceans, and groundwater caused by human activities, which can be harmful to organisms and plants that live in these water bodies. It occurs when pollutants are discharged directly into water bodies without treating it first.
Water pollution is a major problem in the global context. It has been suggested that it is the leading worldwide cause of deaths and diseases, and that it accounts for the deaths of more than 14,000 people daily. In addition to the acute problems of water pollution in developing countries, industrialized countries continue to struggle with pollution problems as well. In the most recent national report on water quality in the United States, 45 percent of assessed stream miles, 47 percent of assessed lake acres, and 32 percent of assessed bay and estuarine square miles were classified as polluted.
Water is typically referred to as polluted when it is impaired by anthropogenic contaminants and either does not support a human use, like serving as drinking water, and/or undergoes a marked shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major changes in water quality and the ecological status of water. Water pollution has many causes and characteristics.
ransport and chemical reactions of water pollutants
Most water pollutants are eventually carried by rivers into the oceans. In some areas of the world the influence can be traced hundred miles from the mouth by studies using hydrology transport models. Advanced computer models such as SWMM or the DSSAM Model have been used in many locations worldwide to examine the fate of pollutants in aquatic systems. Indicator filter feeding species such as copepods have also been used to study pollutant fates in the New York Bight, for example. The highest toxin loads are not directly at the mouth of the Hudson River, but 100 kilometers south, since several days are required for incorporation into planktonic tissue. The Hudson discharge flows south along the coast due to coriolis force. Further south then are areas of oxygen depletion, caused by chemicals using up oxygen and by algae blooms, caused by excess nutrients from algal cell death and decomposition. Fish and shellfish kills have been reported, because toxins climb the food chain after small fish consume copepods, then large fish eat smaller fish, etc. Each successive step up the food chain causes a stepwise concentration of pollutants such as heavy metals (e.g. mercury) and persistent organic pollutants such as DDT. This is known as biomagnification, which is occasionally used interchangeably with bioaccumulation.
Large gyres (vortexes) in the oceans trap floating plastic debris. The North Pacific Gyre for example has collected the so-called "Great Pacific Garbage Patch" that is now estimated at 100 times the size of Texas. Many of these long-lasting pieces wind up in the stomachs of marine birds and animals. This results in obstruction of digestive pathways which leads to reduced appetite or even starvation.
Many chemicals undergo reactive decay or chemically change especially over long periods of time in groundwater reservoirs. A noteworthy class of such chemicals is the chlorinated hydrocarbons such as trichloroethylene (used in industrial metal degreasing and electronics manufacturing) and tetrachloroethylene used in the dry cleaning industry (note latest advances in liquid carbon dioxide in dry cleaning that avoids all use of chemicals). Both of these chemicals, which are carcinogens themselves, undergo partial decomposition reactions, leading to new hazardous chemicals (including dichloroethylene and vinyl chloride).
Groundwater pollution is much more difficult to abate than surface pollution because groundwater can move great distances through unseen aquifers. Non-porous aquifers such as clays partially purify water of bacteria by simple filtration (adsorption and absorption), dilution, and, in some cases, chemical reactions and biological activity: however, in some cases, the pollutants merely transform to soil contaminants. Groundwater that moves through cracks and caverns is not filtered and can be transported as easily as surface water. In fact, this can be aggravated by the human tendency to use natural sinkholes as dumps in areas of Karst topography.
There are a variety of secondary effects stemming not from the original pollutant, but a derivative condition. An example is silt-bearing surface runoff, which can inhibit the penetration of sunlight through the water column, hampering photosynthesis in aquatic plants.
Tuesday, April 28, 2009
TSUNAMI
A tsunami is a series of waves that is created when a large volume of a body of water, such as an ocean, is rapidly displaced. The Japanese term is literally translated into "(great) harbor wave."
Earthquakes, volcanic eruptions and other underwater explosions (detonations of nuclear devices at sea), landslides, bolide impacts, and other mass movements above or below water all have the potential to generate a tsunami. Due to the immense volumes of water and energy involved, the effects of tsunamis can be devastating.
The Greek historian Thucydides was the first to relate tsunami to submarine quakes, but understanding of the nature of tsunami remained slim until the 20th century and is the subject of ongoing research.
Many early geological, geographical, and oceanographic texts refer to tsunamis as "seismic sea waves."
Some meteorological storm conditions such as deep depressions causing cyclones, hurricanes, can generate a storm surge which can be several metres above normal tide levels. This is due to the low atmospheric pressure within the centre of the depression. As these storm surges come ashore, they may resemble (though are not) tsunamis, inundating vast areas of land. Such a storm surge inundated Burma (Myanmar) in May 2008.
Causes : - A tsunami can be generated when converging or destructive plate boundaries abruptly move and vertically displace the overlying water. It is very unlikely that they can form at divergent (constructive) or conservative plate boundaries. This is because constructive or conservative boundaries do not generally disturb the vertical displacement of the water column. Subduction zone related earthquakes generate the majority of all tsunamis.
Tsunamis have a small amplitude (wave height) offshore, and a very long wavelength (often hundreds of kilometers long), which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 mm above the normal sea surface. They grow in height when they reach shallower water, in a "shoaling" process described below. A tsunami can occur at any state of the tide and even at low tide will still inundate coastal areas if the incoming waves surge high enough.
On April 1, 1946 a Magnitude 7.8 (Richter Scale) earthquake occurred near the Aleutian Islands, Alaska. It generated a tsunami which inundated Hilo on the island of Hawai'i with a 14 m high surge. The area where the earthquake occurred is where the Pacific Ocean floor is subducting (or being pushed downwards) under Alaska.
Examples of tsunami being generated at locations away from convergent boundaries include Storegga during the Neolithic era, Grand Banks 1929, Papua New Guinea 1998 (Tappin, 2001). In the case of the Grand Banks and Papua New Guinea tsunamis an earthquake caused sediments to become unstable and subsequently fail. These slumped and as they flowed down slope a tsunami was generated. These tsunami did not travel transoceanic distances.
It is not known what caused the Storegga sediments to fail. It may have been due to overloading of the sediments causing them to become unstable and they then failed solely as a result of being overloaded. It is also possible that an earthquake caused the sediments to become unstable and then fail. Another theory is that a release of gas hydrates (methane etc.,) caused the slump.
The "Great Chilean earthquake" (19:11 hrs UTC) May 22, 1960 (9.5 Mw), the March 27, 1964 "Good Friday earthquake" Alaska 1964 (9.2 Mw), and the "Great Sumatra-Andaman earthquake" (00:58:53 UTC) December 26, 2004 (9.2 Mw), are recent examples of powerful megathrust earthquakes that generated a tsunami that was able to cross oceans. Smaller (4.2 Mw) earthquakes in Japan can trigger tsunami that can devastate nearby coasts within 15 minutes or less.
In the 1950s it was hypothesised that larger tsunamis than had previously been believed possible may be caused by landslides, explosive volcanic action e.g., Santorini, Krakatau, and impact events when they contact water. These phenomena rapidly displace large volumes of water, as energy from falling debris or expansion is transferred to the water into which the debris falls at a rate faster than the ocean water can absorb it. They have been named by the media as "mega-tsunami."
Tsunami caused by these mechanisms, unlike the trans-oceanic tsunami caused by some earthquakes, may dissipate quickly and rarely affect coastlines distant from the source due to the small area of sea affected. These events can give rise to much larger local shock waves (solitons), such as the landslide at the head of Lituya Bay 1958, which produced a wave with an initial surge estimated at 524 m. However, an extremely large gravitational landslide might generate a so called "mega-tsunami" that may have the ability to travel trans-oceanic distances. This though is strongly debated and there is no actual geological evidence to support this hypothesis.
Earthquakes, volcanic eruptions and other underwater explosions (detonations of nuclear devices at sea), landslides, bolide impacts, and other mass movements above or below water all have the potential to generate a tsunami. Due to the immense volumes of water and energy involved, the effects of tsunamis can be devastating.
The Greek historian Thucydides was the first to relate tsunami to submarine quakes, but understanding of the nature of tsunami remained slim until the 20th century and is the subject of ongoing research.
Many early geological, geographical, and oceanographic texts refer to tsunamis as "seismic sea waves."
Some meteorological storm conditions such as deep depressions causing cyclones, hurricanes, can generate a storm surge which can be several metres above normal tide levels. This is due to the low atmospheric pressure within the centre of the depression. As these storm surges come ashore, they may resemble (though are not) tsunamis, inundating vast areas of land. Such a storm surge inundated Burma (Myanmar) in May 2008.
Causes : - A tsunami can be generated when converging or destructive plate boundaries abruptly move and vertically displace the overlying water. It is very unlikely that they can form at divergent (constructive) or conservative plate boundaries. This is because constructive or conservative boundaries do not generally disturb the vertical displacement of the water column. Subduction zone related earthquakes generate the majority of all tsunamis.
Tsunamis have a small amplitude (wave height) offshore, and a very long wavelength (often hundreds of kilometers long), which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 mm above the normal sea surface. They grow in height when they reach shallower water, in a "shoaling" process described below. A tsunami can occur at any state of the tide and even at low tide will still inundate coastal areas if the incoming waves surge high enough.
On April 1, 1946 a Magnitude 7.8 (Richter Scale) earthquake occurred near the Aleutian Islands, Alaska. It generated a tsunami which inundated Hilo on the island of Hawai'i with a 14 m high surge. The area where the earthquake occurred is where the Pacific Ocean floor is subducting (or being pushed downwards) under Alaska.
Examples of tsunami being generated at locations away from convergent boundaries include Storegga during the Neolithic era, Grand Banks 1929, Papua New Guinea 1998 (Tappin, 2001). In the case of the Grand Banks and Papua New Guinea tsunamis an earthquake caused sediments to become unstable and subsequently fail. These slumped and as they flowed down slope a tsunami was generated. These tsunami did not travel transoceanic distances.
It is not known what caused the Storegga sediments to fail. It may have been due to overloading of the sediments causing them to become unstable and they then failed solely as a result of being overloaded. It is also possible that an earthquake caused the sediments to become unstable and then fail. Another theory is that a release of gas hydrates (methane etc.,) caused the slump.
The "Great Chilean earthquake" (19:11 hrs UTC) May 22, 1960 (9.5 Mw), the March 27, 1964 "Good Friday earthquake" Alaska 1964 (9.2 Mw), and the "Great Sumatra-Andaman earthquake" (00:58:53 UTC) December 26, 2004 (9.2 Mw), are recent examples of powerful megathrust earthquakes that generated a tsunami that was able to cross oceans. Smaller (4.2 Mw) earthquakes in Japan can trigger tsunami that can devastate nearby coasts within 15 minutes or less.
In the 1950s it was hypothesised that larger tsunamis than had previously been believed possible may be caused by landslides, explosive volcanic action e.g., Santorini, Krakatau, and impact events when they contact water. These phenomena rapidly displace large volumes of water, as energy from falling debris or expansion is transferred to the water into which the debris falls at a rate faster than the ocean water can absorb it. They have been named by the media as "mega-tsunami."
Tsunami caused by these mechanisms, unlike the trans-oceanic tsunami caused by some earthquakes, may dissipate quickly and rarely affect coastlines distant from the source due to the small area of sea affected. These events can give rise to much larger local shock waves (solitons), such as the landslide at the head of Lituya Bay 1958, which produced a wave with an initial surge estimated at 524 m. However, an extremely large gravitational landslide might generate a so called "mega-tsunami" that may have the ability to travel trans-oceanic distances. This though is strongly debated and there is no actual geological evidence to support this hypothesis.
SECULARISM
Secularism is the assertion that governmental practices or institutions should exist separately from religion and/or religious beliefs.
In one sense, secularism may assert the right to be free from religious rule and teachings, and freedom from the government imposition of religion upon the people, within a state that is neutral on matters of belief, and gives no state privileges or subsidies to religions. (See also Separation of church and state and Laïcité.) In another sense, it refers to a belief that human activities and decisions, especially political ones, should be based on evidence and fact unbiased by religious influence. (See also public reason.)
In its most prominent form, secularism is critical of religious orthodoxy and asserts that religion impedes human progress because of its focus on superstition and dogma versus reason and scientific method. Secularism draws its intellectual roots from Greek and Roman philosophers such as Marcus Aurelius and Epicurus, Enlightenment thinkers like Denis Diderot, Voltaire, Thomas Jefferson, and Thomas Paine, and modern freethinkers, agnostics and atheists such as Robert Ingersoll, Albert Einstein, Sam Harris, and Richard Dawkins.
The purposes and arguments in support of secularism vary widely. In European laicism, it has been argued that secularism is a movement toward modernization, and away from traditional religious values. This type of secularism, on a social or philosophical level, has often occurred while maintaining an official state church or other state support of religion. In the United States, some argue that state secularism has served to a greater extent to protect religion from governmental interference, while secularism on a social level is less prevalent. Within countries as well, differing political movements support secularism for varying reasons.
The term "secularism" was first used by the British writer George Holyoake in 1846. Although the term was new, the general notions of freethought on which it was based had existed throughout history. In particular, early secular ideas involving the separation of philosophy and religion can be traced back to Ibn Rushd (Averroes) and the Averroism school of philosophy. Holyoake invented the term "secularism" to describe his views of promoting a social order separate from religion, without actively dismissing or criticizing religious belief.
An agnostic himself, Holyoake argued that "Secularism is not an argument against Christianity, it is one independent of it. It does not question the pretensions of Christianity; it advances others. Secularism does not say there is no light or guidance elsewhere, but maintains that there is light and guidance in secular truth, whose conditions and sanctions exist independently, and act forever. Secular knowledge is manifestly that kind of knowledge which is founded in this life, which relates to the conduct of this life, conduces to the welfare of this life, and is capable of being tested by the experience of this life."
Barry Kosmin of the Institute for the Study of Secularism in Society and Culture breaks modern secularism into two types: hard and soft secularism. According to Kosmin, "the hard secularist considers religious propositions to be epistemologically illegitimate, warranted by neither reason nor experience." However, in the view of soft secularism, "the attainment of absolute truth was impossible and therefore skepticism and tolerance should be the principle and overriding values in the discussion of science and religion.
In one sense, secularism may assert the right to be free from religious rule and teachings, and freedom from the government imposition of religion upon the people, within a state that is neutral on matters of belief, and gives no state privileges or subsidies to religions. (See also Separation of church and state and Laïcité.) In another sense, it refers to a belief that human activities and decisions, especially political ones, should be based on evidence and fact unbiased by religious influence. (See also public reason.)
In its most prominent form, secularism is critical of religious orthodoxy and asserts that religion impedes human progress because of its focus on superstition and dogma versus reason and scientific method. Secularism draws its intellectual roots from Greek and Roman philosophers such as Marcus Aurelius and Epicurus, Enlightenment thinkers like Denis Diderot, Voltaire, Thomas Jefferson, and Thomas Paine, and modern freethinkers, agnostics and atheists such as Robert Ingersoll, Albert Einstein, Sam Harris, and Richard Dawkins.
The purposes and arguments in support of secularism vary widely. In European laicism, it has been argued that secularism is a movement toward modernization, and away from traditional religious values. This type of secularism, on a social or philosophical level, has often occurred while maintaining an official state church or other state support of religion. In the United States, some argue that state secularism has served to a greater extent to protect religion from governmental interference, while secularism on a social level is less prevalent. Within countries as well, differing political movements support secularism for varying reasons.
The term "secularism" was first used by the British writer George Holyoake in 1846. Although the term was new, the general notions of freethought on which it was based had existed throughout history. In particular, early secular ideas involving the separation of philosophy and religion can be traced back to Ibn Rushd (Averroes) and the Averroism school of philosophy. Holyoake invented the term "secularism" to describe his views of promoting a social order separate from religion, without actively dismissing or criticizing religious belief.
An agnostic himself, Holyoake argued that "Secularism is not an argument against Christianity, it is one independent of it. It does not question the pretensions of Christianity; it advances others. Secularism does not say there is no light or guidance elsewhere, but maintains that there is light and guidance in secular truth, whose conditions and sanctions exist independently, and act forever. Secular knowledge is manifestly that kind of knowledge which is founded in this life, which relates to the conduct of this life, conduces to the welfare of this life, and is capable of being tested by the experience of this life."
Barry Kosmin of the Institute for the Study of Secularism in Society and Culture breaks modern secularism into two types: hard and soft secularism. According to Kosmin, "the hard secularist considers religious propositions to be epistemologically illegitimate, warranted by neither reason nor experience." However, in the view of soft secularism, "the attainment of absolute truth was impossible and therefore skepticism and tolerance should be the principle and overriding values in the discussion of science and religion.
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome (AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV).
This condition progressively reduces the effectiveness of the immune system and leaves individuals susceptible to opportunistic infections and tumors. HIV is transmitted through direct contact of a mucous membrane or the bloodstream with a bodily fluid containing HIV, such as blood, semen, vaginal fluid, preseminal fluid, and breast milk.
This transmission can involve anal, vaginal or oral sex, blood transfusion, contaminated hypodermic needles, exchange between mother and baby during pregnancy, childbirth, or breastfeeding, or other exposure to one of the above bodily fluids.
AIDS is now a pandemic.In 2007, it was estimated that 33.2 million people lived with the disease worldwide, and that AIDS had killed an estimated 2.1 million people, including 330,000 children.Over three-quarters of these deaths occurred in sub-Saharan Africa,retarding economic growth and destroying human capital.
Genetic research indicates that HIV originated in west-central Africa during the late nineteenth or early twentieth century. AIDS was first recognized by the U.S. Centers for Disease Control and Prevention in 1981 and its cause, HIV, identified in the early 1980s.
Although treatments for AIDS and HIV can slow the course of the disease, there is currently no vaccine or cure. Antiretroviral treatment reduces both the mortality and the morbidity of HIV infection, but these drugs are expensive and routine access to antiretroviral medication is not available in all countries.Due to the difficulty in treating HIV infection, preventing infection is a key aim in controlling the AIDS epidemic, with health organizations promoting safe sex and needle-exchange programmes in attempts to slow the spread of the virus.
This condition progressively reduces the effectiveness of the immune system and leaves individuals susceptible to opportunistic infections and tumors. HIV is transmitted through direct contact of a mucous membrane or the bloodstream with a bodily fluid containing HIV, such as blood, semen, vaginal fluid, preseminal fluid, and breast milk.
This transmission can involve anal, vaginal or oral sex, blood transfusion, contaminated hypodermic needles, exchange between mother and baby during pregnancy, childbirth, or breastfeeding, or other exposure to one of the above bodily fluids.
AIDS is now a pandemic.In 2007, it was estimated that 33.2 million people lived with the disease worldwide, and that AIDS had killed an estimated 2.1 million people, including 330,000 children.Over three-quarters of these deaths occurred in sub-Saharan Africa,retarding economic growth and destroying human capital.
Genetic research indicates that HIV originated in west-central Africa during the late nineteenth or early twentieth century. AIDS was first recognized by the U.S. Centers for Disease Control and Prevention in 1981 and its cause, HIV, identified in the early 1980s.
Although treatments for AIDS and HIV can slow the course of the disease, there is currently no vaccine or cure. Antiretroviral treatment reduces both the mortality and the morbidity of HIV infection, but these drugs are expensive and routine access to antiretroviral medication is not available in all countries.Due to the difficulty in treating HIV infection, preventing infection is a key aim in controlling the AIDS epidemic, with health organizations promoting safe sex and needle-exchange programmes in attempts to slow the spread of the virus.
FEMALE EDUCATION
Female education is a catch-all term for a complex of issues and debates surrounding education (primary education, secondary education, tertiary education and health education in particular) for females. It includes areas of gender equality and access to education, and its connection to the alleviation of poverty. Also involved are the issues of single-sex education and religious education, in that the division of education along gender lines, and religious teachings on education, have been traditionally dominant, and are still highly relevant in contemporary discussion of female education as a global consideration. While the feminist movement has certainly promoted the importance of the issues attached to female education, discussion is wide-ranging and by no means confined to narrow terms of reference: it includes for example AIDS.
Modern period : - The issue of female education in the large, as emancipatory and rational, is broached seriously in the Enlightenment. Mary Wollstonecraft is a writer who dealt with it in those terms.
Actual progress in institutional terms, for secular education of women, began in the West in the nineteenth century, with the founding of colleges offering single-sex education to young women. These appeared in the middle of the century. The Princess: A Medley, a narrative poem by Alfred Lord Tennyson, is a satire of women's education, still a controversial subject in 1848, when Queen's College first opened in London. Emily Davies campaigned for women's education in the 1860s, and founded Girton College in 1869.
W. S. Gilbert parodied the poem and treated the themes of women's higher education and feminism in general with The Princess in (1870) and Princess Ida in 1883. Once women began to graduate from institutions of higher education, there steadily developed also a stronger academic stream of schooling, and the teacher training of women in larger numbers, principally to provide primary education. Women's access to traditionally all-male institutions took several generations to become complete.
Educational reform : - The interrelated themes of barriers to education and employment continued to form the backbone of feminist thought in the nineteenth century, as described, for instance by Harriet Martineau in her 1859 article “Female Industry” in the Edinburgh Journal. The economy was changing but women’s lot was not. Martineau, however, remained a moderate, for practical reasons, and unlike Cobbe, did not support the emerging call for the vote.
Slowly the efforts of women like Davies and the Langham group started to make inroads. Queen’s College (1848) and Bedford College (1849) in London were starting to offer some education to women from 1848, and by 1862 Davies was establishing a committee to persuade the universities to allow women to sit for the recently established (1858) Local Examinations, with partial success (1865). A year later she published “The Higher Education of Women.” She and Leigh Smith founded the first higher educational institution for women, with 5 students, which became Girton College, Cambridge in 1873, followed by Lady Margaret Hall at Oxford in 1879. Bedford had started awarding degrees the previous year. Despite these measurable advances, few could take advantage of them and life for women students was very difficult.
As part of the continuing dialogue between British and American feminists, Elizabeth Blackwell, the first woman in the US to graduate in medicine (1849), lectured in Britain with Langham support. They also supported Elizabeth Garrett’s attempts to assail the walls of British medical education against virulent opposition, eventually taking her degree in France. Garrett’s very successful campaign to run for office on the London School Board in 1870 is another example of a how a small band of very determined women were starting to reach positions of influence at the level of local government and public bodies.
Modern period : - The issue of female education in the large, as emancipatory and rational, is broached seriously in the Enlightenment. Mary Wollstonecraft is a writer who dealt with it in those terms.
Actual progress in institutional terms, for secular education of women, began in the West in the nineteenth century, with the founding of colleges offering single-sex education to young women. These appeared in the middle of the century. The Princess: A Medley, a narrative poem by Alfred Lord Tennyson, is a satire of women's education, still a controversial subject in 1848, when Queen's College first opened in London. Emily Davies campaigned for women's education in the 1860s, and founded Girton College in 1869.
W. S. Gilbert parodied the poem and treated the themes of women's higher education and feminism in general with The Princess in (1870) and Princess Ida in 1883. Once women began to graduate from institutions of higher education, there steadily developed also a stronger academic stream of schooling, and the teacher training of women in larger numbers, principally to provide primary education. Women's access to traditionally all-male institutions took several generations to become complete.
Educational reform : - The interrelated themes of barriers to education and employment continued to form the backbone of feminist thought in the nineteenth century, as described, for instance by Harriet Martineau in her 1859 article “Female Industry” in the Edinburgh Journal. The economy was changing but women’s lot was not. Martineau, however, remained a moderate, for practical reasons, and unlike Cobbe, did not support the emerging call for the vote.
Slowly the efforts of women like Davies and the Langham group started to make inroads. Queen’s College (1848) and Bedford College (1849) in London were starting to offer some education to women from 1848, and by 1862 Davies was establishing a committee to persuade the universities to allow women to sit for the recently established (1858) Local Examinations, with partial success (1865). A year later she published “The Higher Education of Women.” She and Leigh Smith founded the first higher educational institution for women, with 5 students, which became Girton College, Cambridge in 1873, followed by Lady Margaret Hall at Oxford in 1879. Bedford had started awarding degrees the previous year. Despite these measurable advances, few could take advantage of them and life for women students was very difficult.
As part of the continuing dialogue between British and American feminists, Elizabeth Blackwell, the first woman in the US to graduate in medicine (1849), lectured in Britain with Langham support. They also supported Elizabeth Garrett’s attempts to assail the walls of British medical education against virulent opposition, eventually taking her degree in France. Garrett’s very successful campaign to run for office on the London School Board in 1870 is another example of a how a small band of very determined women were starting to reach positions of influence at the level of local government and public bodies.
MASS MEDIA
Mass media is a term used to denote a section of the media specifically envisioned and designed to reach a very large audience such as the population of a nation state. It was coined in the 1920s with the advent of nationwide radio networks, mass-circulation newspapers and magazines, although mass media (like books and manuscripts) were present centuries before the term became common.
The term public media has a similar meaning: it is the sum of the public mass distributors of news and entertainment across media such as newspapers, television, radio, broadcasting, which may require union membership in some large markets such as Newspaper Guild, AFTRA, & text publishers. The concept of mass media is now complicated by Internet media (like blogs, message boards, podcasts, and video sharing) because individuals now have a means to exposure that is comparable in scale to that previously restricted to a select group of mass media producers.
The communications audience has been viewed by some commentators as forming a mass society with special characteristics, notably atomization or lack of social connections, which render it especially susceptible to the influence of modern mass-media techniques such as advertising and propaganda. The term "MSM" or "mainstream media" has been widely used in the blogosphere in discussion of the mass media and media bias.
Types of drama in numerous cultures were probably the first mass-media, going back into the Ancient World. The first dated printed book known is the "Diamond Sutra", printed in China in 868 AD, although it is clear that books were printed earlier. Movable clay type was invented in 1041 in China. However, due to the slow spread of literacy to the masses in China, and the relatively high cost of paper there, the earliest printed mass-medium was probably European popular prints from about 1400. Although these were produced in huge numbers, very few early examples survive, and even most known to be printed before about 1600 have not survived. Johannes Gutenberg printed the first book on a printing press with movable type in 1453. This invention transformed the way the world received printed materials, although books remained too expensive really to be called a mass-medium for at least a century after that.
Newspapers developed around from 1612, with the first example in English in 1620 ; but they took until the nineteenth century to reach a mass-audience directly.
During the 20th century, the growth of mass media was driven by technology that allowed the massive duplication of material. Physical duplication technologies such as printing, record pressing and film duplication allowed the duplication of books, newspapers and movies at low prices to huge audiences. Radio and television allowed the electronic duplication of information for the first time.
Mass media had the economics of linear replication: a single work could make money proportional to the number of copies sold, and as volumes went up, units costs went down, increasing profit margins further. Vast fortunes were to be made in mass media. In a democratic society, independent media serve /electorate about issues regarding government and corporate entities (see Media influence). Some consider the concentration of media ownership to be a grave threat to democracy.
The term public media has a similar meaning: it is the sum of the public mass distributors of news and entertainment across media such as newspapers, television, radio, broadcasting, which may require union membership in some large markets such as Newspaper Guild, AFTRA, & text publishers. The concept of mass media is now complicated by Internet media (like blogs, message boards, podcasts, and video sharing) because individuals now have a means to exposure that is comparable in scale to that previously restricted to a select group of mass media producers.
The communications audience has been viewed by some commentators as forming a mass society with special characteristics, notably atomization or lack of social connections, which render it especially susceptible to the influence of modern mass-media techniques such as advertising and propaganda. The term "MSM" or "mainstream media" has been widely used in the blogosphere in discussion of the mass media and media bias.
Types of drama in numerous cultures were probably the first mass-media, going back into the Ancient World. The first dated printed book known is the "Diamond Sutra", printed in China in 868 AD, although it is clear that books were printed earlier. Movable clay type was invented in 1041 in China. However, due to the slow spread of literacy to the masses in China, and the relatively high cost of paper there, the earliest printed mass-medium was probably European popular prints from about 1400. Although these were produced in huge numbers, very few early examples survive, and even most known to be printed before about 1600 have not survived. Johannes Gutenberg printed the first book on a printing press with movable type in 1453. This invention transformed the way the world received printed materials, although books remained too expensive really to be called a mass-medium for at least a century after that.
Newspapers developed around from 1612, with the first example in English in 1620 ; but they took until the nineteenth century to reach a mass-audience directly.
During the 20th century, the growth of mass media was driven by technology that allowed the massive duplication of material. Physical duplication technologies such as printing, record pressing and film duplication allowed the duplication of books, newspapers and movies at low prices to huge audiences. Radio and television allowed the electronic duplication of information for the first time.
Mass media had the economics of linear replication: a single work could make money proportional to the number of copies sold, and as volumes went up, units costs went down, increasing profit margins further. Vast fortunes were to be made in mass media. In a democratic society, independent media serve /electorate about issues regarding government and corporate entities (see Media influence). Some consider the concentration of media ownership to be a grave threat to democracy.
PHYSICAL ORGANIC CHEMISTRY
Physical organic chemistry is the study of the interrelationships between structure and reactivity in organic molecules. It can be seen as the study of organic chemistry using tools of physical chemistry such as chemical equilibrium, chemical kinetics, thermochemistry, and quantum chemistry. The term "physical organic chemistry" is commonly attributed to Louis Hammett, who used it as a title for a book in 1940.
The two main themes in physical organic chemistry are structure and reactivity. The study of structure starts from chemical bonding, with special emphasis on the stability of organic molecules due to factors such as steric strain and aromaticity. Other topics in structure include stereochemistry and conformational analysis. Supramolecular structure is also considered in terms of intermolecular forces including hydrogen bonding. Finally, the acid-base chemistry of the molecules is studied in terms of structure, based on resonance and inductive effects and through the use of linear free-energy relations.
The study of reactivity focuses on the mechanisms of organic reactions. It uses chemical kinetics, spectroscopy, isotope effects, and quantum chemistry to determine the sequence of elementary steps involved in a reaction. These elementary steps can be classified in a few major classes: addition, elimination, substitution, and pericyclic reactions. The mechanisms are commonly expressed in terms of "electron pushing" and potential energy surfaces. Other major topics are photochemistry, the effect of light on the reactivity of organic molecules, and solvent effects on organic reactions.
Structure and reactivity are both involved in the study of reaction intermediates—the transient species involved in reaction mechanisms. The main types of intermediates of interest are carbocations, carbanions, free radicals, and carbenes. Usually, these intermediates are not isolated, but their presence is inferred from stereochemical evidence, spectroscopy, or through the use of chemical traps. In some cases, however, it is possible to isolate these types of molecules at very low temperatures (cryochemistry) or via matrix isolation. It is also possible to create specific derivatives that are stabilized through chemical means such as resonance, as in the case of the triphenylmethyl radical.
The two main themes in physical organic chemistry are structure and reactivity. The study of structure starts from chemical bonding, with special emphasis on the stability of organic molecules due to factors such as steric strain and aromaticity. Other topics in structure include stereochemistry and conformational analysis. Supramolecular structure is also considered in terms of intermolecular forces including hydrogen bonding. Finally, the acid-base chemistry of the molecules is studied in terms of structure, based on resonance and inductive effects and through the use of linear free-energy relations.
The study of reactivity focuses on the mechanisms of organic reactions. It uses chemical kinetics, spectroscopy, isotope effects, and quantum chemistry to determine the sequence of elementary steps involved in a reaction. These elementary steps can be classified in a few major classes: addition, elimination, substitution, and pericyclic reactions. The mechanisms are commonly expressed in terms of "electron pushing" and potential energy surfaces. Other major topics are photochemistry, the effect of light on the reactivity of organic molecules, and solvent effects on organic reactions.
Structure and reactivity are both involved in the study of reaction intermediates—the transient species involved in reaction mechanisms. The main types of intermediates of interest are carbocations, carbanions, free radicals, and carbenes. Usually, these intermediates are not isolated, but their presence is inferred from stereochemical evidence, spectroscopy, or through the use of chemical traps. In some cases, however, it is possible to isolate these types of molecules at very low temperatures (cryochemistry) or via matrix isolation. It is also possible to create specific derivatives that are stabilized through chemical means such as resonance, as in the case of the triphenylmethyl radical.
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