Who is Rachel Carson?

Rachel Carson was born in a small rural Pennsylvania community near the Allegheny River, where she spent a great deal of time exploring the forests and streams around her 65-acre farm. As a young child, Carson's consuming passions were the nature surrounding her hillside home and her writing. She was first "published" at the age of 10 in a children magazine dedicated to the work of young writers. Other youngsters who first saw their words in print in St. Nicholas included William Faulkner and F. Scott Fitzgerald.

In 1925 Carson entered Pennsylvania College for Women as an English major determined to become a writer. Midway into her studies, however, she switched to biology. Her first experience with the ocean came during a summer fellowship at the U.S. Marine Laboratory in Woods Hole, Massachusetts. Upon graduation from Pennsylvania College, Carson was awarded a scholarship to complete her graduate work in biology at Johns Hopkins University in Baltimore, an enormous accomplishment for a woman in 1929.

Carson's distinction in both writing and biology won her a part-time position with the U.S. Bureau of Fisheries in 1935 where she was asked to create a series of seven-minute radio programs on marine life called "Romance Under the Waters." Meantime, she continued to submit writings on conservation and nature to newspapers and magazines, urging from the very beginning the need to regulate the "forces of destruction" and consider always the welfare of the "fish as well as that of the fisherman." Her articles were published regularly by the Baltimore Sun and other of its syndicated papers.A

In 1936, Carson was appointed a junior aquatic biologist with the Bureau of Fisheries and became one of only two women then employed with the Bureau at a professional level. Her work allowed her to visit often the Chesapeake Bay region, where she spoke with watermen and toured commercial plants and conservation facilities in an effort to understand the economics and culture of the area. During World War II, Carson participated in a program to investigate undersea sounds, life and terrain designed to assist the Navy in developing techniques and equipment for submarine detection.

Carson's first book, Under the Sea-Wind, published in 1941, highlighted her unique ability to present deeply intricate scientific material in clear poetic language that could captivate her readers and pique their interest in the natural world. In 1943, Carson was promoted to the position of aquatic biologist in the newly created U.S. Fish and Wildlife Service, where she authored many bulletins directed at the American public. One series, known as "Conservation in Action," was devoted to exploring wildlife and ecology on national wildlife refuges in laymen's terms. Another series was entitled "Food from the Sea" and offered information on the proper preparation as well as the advantages of a diet including fish and shellfish to a public unused to eating freshwater fish.

Carson was moved to the position of assistant editor and then editor-in-chief of all Fish and Wildlife Service publications, where her work included reviewing manuscripts as well as overseeing the Fish and Wildlife Service library and its staff, preparing congressional testimony and writing speeches for Fish and Wildlife Service personnel.
"...her book provoked a firestorm of controversy as
well as personal attacks on her professional integrity."

In 1951 Carson's second book, The Sea Around Us, was published and eventually translated into 32 languages. It was on The New York Times' best-seller list for 81 weeks. The success of her second book prompted Carson to resign her position at the Service in 1952 to devote her time to writing. The Sea Around Us, along with The Edge of the Sea, a third book published in 1956, opened a new perspective to concerned environmentalists on the term "ecology," the study of "our living place." But it was her last book, Silent Spring, published in 1962, that awakened society to a responsibility to other forms of life. In it, Carson documents in minute biological detail the true menace to the ecosystem caused by harmful pesticides.
Original dust cover for Silent Spring

Carson had become interested in the danger of pesticides while still associated with the Fish and Wildlife Service. Her concern was accelerated with the introduction of DDT in 1945. Although she had left the Service to work on Silent Spring, her marine studies while there had provided her with early documentation on the effects of DDT on marine life. Since abnormalities always show up first in fish and wildlife, biologists were the first to see the effects of impending danger to the overall environment.

Carson had long been aware of the dangers of chemical pesticides but was also aware of the controversy within the agricultural community, which needed such pesticides to increase crop production. She had long hoped someone else would publish an expose' on DDT but realized finally that only she had the background as well as the economic freedom to do it. She made the decision to produce Silent Spring after years of research across the United States and Europe with the help of Shirley Briggs, a former Fish and Wildlife Service artist who had become editor of an Audubon Naturalist Society magazine called Atlantic Naturalist. Clarence Cottam, another former Fish and Wildlife Service employee, also provided Carson with support and documentation on DDT research conducted but not generally known.

As expected, her book provoked a firestorm of controversy as well as personal attacks on her professional integrity. The pesticide industry mounted a massive campaign to discredit Carson even though she did not urge the complete banning of pesticides but rather that research be conducted to ensure pesticides were used safely and alternatives to dangerous chemicals such as DDT be found. The federal government, however, ordered a complete review of its pesticide policy and Carson was asked to testify before a Congressional committee along with other witnesses. As a direct result of the study, DDT was banned. With the publication of Silent Spring, Carson is credited with launching the contemporary environmental movement and awakening concern by thinking Americans about the environment.

In a television interview, Carson once stated that "man's endeavors to control nature by his powers to alter and to destroy would inevitably evolve into a war against himself, a war he would lose unless he came to terms with nature." She died from cancer in 1964 at the age of 57. The Fish and Wildlife Service named one of its refuges near Carson's summer home on the coast of Maine as the Rachel Carson National Wildlife Refuge in 1969 to honor the memory of this extraordinary woman.

Blood Pressure Categories by Race/Ethnicity, United States

Know your blood pressure level and check it regularly; detect high blood pressure before it causes serious health problems.

This Data & Statistics feature highlights the percentage distribution of blood pressure categories by race/ethnicity as measured in the National Health and Nutrition Examination Survey (NHANES).

Blood pressure categories are based on the classification recommended by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure and are defined as follows: normal (systolic blood pressure <120 mm Hg and a diastolic blood pressure <80 mm Hg); pre-hypertension (systolic blood pressure 120--139 mm Hg or diastolic blood pressure 80--89 mm Hg); hypertension stage 1 (systolic blood pressure 140--159 mm Hg or diastolic blood pressure 90--99 mm Hg); and hypertension stage 2 (systolic blood pressure >160 mm Hg or diastolic blood pressure >100 mm Hg). Persons are classified into the higher blood pressure group if the systolic and diastolic values fall within more than one category. Categories do not account for blood pressure treatment status.

Blood pressure category varied substantially by race/ethnicity. Mexican Americans and non-Hispanic whites were more likely to have normal blood pressure compared with non-Hispanic blacks. Conversely, higher percentages of non-Hispanic blacks had hypertension stage 1 and hypertension stage 2 compared with non-Hispanic whites and Mexican Americans.





Source:

National Health and Nutrition Examination Survey 1999--2004. Available at http://www.cdc.gov/nchs/nhanes.htm.

What is Life?

Life Is Cells


People like to say, as if it were obvious, that life is hard to define. This is misleading. Life has properties that clearly distinguish it from everything else. First, every living thing is cellular. In other words, it is either a single-celled creature or a creature composed of many cells. Every cell is bounded by its own outer membrane and contains a full set of instructions necessary for its operation and reproduction. Furthermore, every cell uses the same operating system: "DNA makes RNA makes protein." DNA is a long complex molecule that contains the cell's instructions. It is transcribed into RNA, another long complex molecule similar to DNA; and then the RNA transcript is translated into protein. There are hundreds of billions of different proteins used by living things (3), but all of them are made from the same twenty amino acids, the "building blocks of life."
Other Properties of Life
+ Living things reproduce themselves. Either individually or in sexual pairs, they have both the encoded instructions and the machinery necessary for self-reproduction. (Some creatures cannot reproduce, but every creature comes from reproduction.) Periodic crystals like sodium chloride (table salt) also undergo a kind of self-reproduction. In crystals however, the "instructions" are much simpler, they are not encoded, and they are not different from the "machinery."
+ Life uses processes collectively called metabolism to convert materials and energy for its needs. Metabolism creates waste products. When metabolism ceases with no prospect of starting again, we call it death. Machines also convert materials and energy for their needs, create waste, and could be said to die.
+ Life undergoes evolution. Notably, simpler forms are succeeded by forms with greater organization. Cars evolve also, in their way. Computers do, too. And computers even contain their own encoded instruction sets.


These latter properties of life are sometimes used to make the point that life is hard to define. But nothing else has all of these latter properties except cellular life using life's DNA—RNA—protein operating system. Another kind of life, entirely different from ours, is conceivable, yes. But the only kind we have ever seen is the one we are part of here on Earth. As biologist and philosopher Harold J. Morowitz says, "The only life we know for certain is cellular..." (4).

Viruses and prions are not alive; they lie on the fringe of life. Viruses contain instructions encoded in DNA or RNA. (Prions don't.) Both are reproduced. Viruses certainly and prions probably can evolve. But neither can reproduce itself; each needs the machinery of a living cell to carry out its reproduction. Without a cell, viruses and prions are merely inert, complicated particles which do nothing. Do they make it hard to define life? No, just as trailers don't make it hard to define motor vehicle traffic. We know what motor vehicle traffic is. And we know what life is.
A Cell Is Like a Computer
All the regularities of biology strike me as being exactly like the regularities of engineering — Daniel C. Dennett (4.5)

One analogy for a cell is a computer. Computers have coded instructions inside them called programs. The programs in computers are analogous to the genetic programming in the DNA within cells. DNA is subdivided into functional units called genes; these would correspond to files in the computer. A computer even has a metabolism: it consumes electrical energy and discharges heat.

The programs in cells and those in computers can both be 1) copied and 2) executed. Some of the proteins made when a genetic program is executed would loosely correspond to the computer's paper printout. But other proteins are more analogous to the computer's cabinetry or wiring. Of course, computers don't make their own cabinetry or wiring; the analogy is not perfect.

In fact, nothing about the computer is analogous to a cell's reproduction. A cell can make a complete copy of itself; it contains the complete instructions (programs) and the cellular machinery (hardware) necessary to reproduce itself. A computer cannot make a copy of itself. It lacks the necssary machinery (but it may be able to reproduce its instruction set by "automatic full backup".) A computer that could reproduce itself would be more properly described as a self-reproducing robot. Such a thing is conceivable, but none exists on Earth today.

A multicelled creature is like a network of computers. It requires parallel computer architecture on a huge scale to operate multicelled creatures such as mammals with billions or trillions of cells, all working in harmony, each doing its task. The nervous system and the hormonal system are two important networking systems used by mammals.

Changing the way a computer works requires new programs. Sometimes one can simply insert a disc into a slot: the computer recognizes the disc, accepts its new code, and uses it. Other times, reprogramming a computer is more trouble. The new software may have "bugs"; it may not be compatible with the existing software; additional software patches may be needed; it may introduce a computer virus; or it may cause everything to crash without explanation.

Biological evolution happens when cells are reprogrammed. Somehow, new genetic programs are installed and activated. How does new genetic software get installed and activated? And where does it come from? These are some of the questions that Cosmic Ancestry attempts to answer.

Blood Types

Although all blood is made of the same basic elements, not all blood is alike. In fact, there are eight different common blood types, which are determined by the presence or absence of certain antigens – substances that can trigger an immune response if they are foreign to the body. Since some antigens can trigger a patient's immune system to attack the transfused blood, safe blood transfusions depend on careful blood typing and cross-matching.
The ABO Blood Group System

There are four major blood groups determined by the presence or absence of two antigens – A and B – on the surface of red blood cells:

* Group A – has only the A antigen on red cells (and B antibody in the plasma)
* Group B – has only the B antigen on red cells (and A antibody in the plasma)
* Group AB – has both A and B antigens on red cells (but neither A nor B antibody in the plasma)
* Group O – has neither A nor B antigens on red cells (but both A and B antibody are in the plasma)


How is our blood type determined?

*It’s inherited. Like eye color, blood type is passed genetically from your parents. Whether your blood group is type A, B, AB or O is based on the blood types of your mother and father.



This chart shows the potential blood types you may inherit.

Trichonella spriralis

The parasite may be found in a wide variety of animals, including pigs, dogs, cats, rats, and many wild animals (such as fox, wolf, and polar bear). The disease is found only among those who eat pork, primarily in North America and Europe. Up to 5 percent of Americans have had an infestation, usually without symptoms. It is almost never a problem in countries such as France, where pigs eat root vegetables, not garbage.

Diversity of the tribes of Man

The Human Genome Project found all humans to have a 99.9 % similar genetic content and identity, but this is challenged by a new more detailed research suggesting a higher genetic diversity, with further medical and evolutionary implications.

Previous studies focused on analyzing polymorphism (variation) in DNA nucleotidic bases. But the new approach tackled deletions or duplications of code among relatively long sequences of individual DNA and then compared the so-called copy number variations (CNVs) across individuals from different human breeds. This method uncovered a complex, higher-order variation in the code and better explains why some populations or races are vulnerable to certain diseases and respond well to specific drugs, while counterparts
swiftly fall sick or never respond to treatment.

Two technical breakthroughs, a faster, accurate sequencing of DNA and a powerful software programme to spot the CNVs allowed the new approach. 1,447 CNVs were located in roughly 2,900 genes, which means around 12 % of the human DNA. “Each one of us has a unique pattern of gains and losses of complete sections of DNA,” said Matthew Hurles from Britain’s Wellcome Trust Sanger Institute. “One of the real surprises of these results was just how much of our DNA varies in copy number. We estimate this to be at least 12 % of the genome.”

“The copy number variation that researchers had seen before was simply the tip of the iceberg, while the bulk lay submerged, undetected. We now appreciate the immense contribution of this phenomenon to genetic differences between individuals.”

Some missing or duplicated DNA fragments are very large, thus CNVs might have a big impact on gene expression. About 16 % of genes related to disease have been found to possess CNVs, like those involved in the rare DiGeorge, Williams-Beuren and Prader-Willi syndromes or more common schizophrenia, cataracts, spinal muscular atrophy and atherosclerosis. But kidney disease, Parkinson’s, Alzheimer’s and vulnerability to malaria and the human immunodeficiency virus (HIV), which recent research has blamed on single-letter variations in the gene code, are also suspected for CNVs. “The stage is set for global studies to explore anew… the clinical significance of human variation,” said Huntington Willard at Duke University in North Carolina.

The new data also shows that our species is so recent that the vast majority of CNVs, around 89 %, was found to be shared among the 269 people belonging to Mongoloid Race (Japanese and Chinese), African Negroid (Yoruba Nigerians) and Caucasoid (of Northern and Western European ancestry). But there are also widespread specific differences in CNVs according to the race and even inside the same race according to population (geographical origin). This means that over 200,000 years or so, natural selection favored subtle variants allowing different humans populations to adapt to their different environments, with specific climate, pathogens, and food resources.

Mitchondira Eve, Our common ancestor

Eve is important because there is a direct female line to her from all living humans. She is not our only common ancestor, nor is she our most recent. However, more recent ancestors are hard to date because of the mixing of the genes in sex.