Martin Wolff's Profile

“The old view is that cancer is a linear process,” said Dr. Barnett Kramer, associate director for disease prevention at the National Institutes of Health. “A cell acquired a mutation, and little by little it acquired more and more mutations. Mutations are not supposed to revert spontaneously.”

So, Dr. Kramer said, the image was “an arrow that moved in one direction.” But now, he added, it is becoming increasingly clear that cancers require more than mutations to progress. They need the cooperation of surrounding cells and even, he said, “the whole organism, the person,” whose immune system or hormone levels, for example, can squelch or fuel a tumor.

The deal with fish oil, I found out, is that a considerable portion of it comes from a creature upon which the entire Atlantic coastal ecosystem relies, a big-headed, smelly, foot-long member of the herring family called menhaden, which a recent book identifies in its title as “The Most Important Fish in the Sea.”

But menhaden are entering the final losing phases of a century-and-a-half fight for survival that began when humans started turning huge schools into fertilizer and lamp oil.

PLAYA GRANDE, Costa Rica — This resort town was long known for Leatherback Sea Turtle National Park, nightly turtle beach tours and even a sea turtle museum.

But haphazard development, in tandem with warmer temperatures and rising seas that many scientists link to global warming, have vastly diminished the Pacific turtle population.

“I don’t think a lot of people understand the gravity of the issue,” said a senior police official in Punjab, who declined to be idenfitied because he was discussing threats to the state. “If you want to destabilize Pakistan, you have to destabilize Punjab.”

An internationally recognized ornithologist, Mr. Belton was almost single-handedly responsible for the current body of knowledge of the bird life of Rio Grande do Sul, the southernmost Brazilian state. His field recordings and specimens from the region are today in the collections of major research institutions. His two-volume study of the birds of the area is widely considered seminal.

Mr. Belton’s accomplishments are all the more unusual in that as an ornithologist, he was completely self-taught.

In 1956, Dr. Zamecnik and his colleagues Dr. Mahlon Hoagland (who died on Sept. 18) and Dr. Mary Stephenson discovered a critical element of the protein synthesis pathway: the molecule that shuttles amino acids to the cell’s protein factory, called the ribosome. There they are linked to create a chain that folds to form a protein. This newfound molecule they called transfer RNA, or tRNA. The discovery was a milestone in molecular biology.

In 1996, Dr. Zamecnik received the Albert Lasker Award for Special Achievement in Medical Science “for brilliant and original science that revolutionized biochemistry and spawned new avenues of scientific inquiry.” In 1991 he was awarded the National Medal of Science.

The new command’s mission will be to coordinate the day-to-day operation — and protection — of military and Pentagon computer networks. Currently, the Defense Department operates 15,000 separate computer networks and more than seven million individual computers or information-technology devices, officials said.

The Obama administration has undertaken significant efforts to protect the nation from cyberattack and prepare for potential offensive operations against adversary computer networks.

Part philosopher, part sociologist and entirely humanist, he studied tribes in Brazil and North America, concluding that virtually all societies shared powerful commonalities of behavior and thought, often expressing them in myths.

He concluded that primitive peoples were no less intelligent than "Western" civilizations and that their intelligence could be revealed through their myths and other cultural keystones. Those myths, he argued, all tend to provide answers to such universal questions as "Who are we?" and "How did we come to be in this time and place?"

“It’s hard to believe that this is what’s melting the glaciers,” said Dr. Veerabhadran Ramanathan, one of the world’s leading climate scientists, as he weaved through a warren of mud brick huts, each containing a mud cookstove pouring soot into the atmosphere.

As women in ragged saris of a thousand hues bake bread and stew lentils in the early evening over fires fueled by twigs and dung, children cough from the dense smoke that fills their homes. Black grime coats the undersides of thatched roofs. At dawn, a brown cloud stretches over the landscape like a diaphanous dirty blanket.

Cohn pioneered the use of stable isotopic tracers to study the mechanisms of enzymes, which are the proteins that carry out chemical reactions within the cell. Stable isotopes, such as carbon-13 and oxygen-18, have the same chemical properties as their more common sisters -- in this case, carbon-12 and oxygen-16 -- but they do not disintegrate radioactively. When stable isotopes are incorporated into molecules in the cell, their heavier weight allows them to be traced, providing insights into biochemical reactions.

Cohn also did critical work in nuclear magnetic resonance (NMR), an imaging technique that allows chemists to examine the structure of proteins and other molecules in solution. Her early studies illuminated the role of adenosine triphosphate, or ATP, one of the crucial energy sources within the cell. Over her career, she published more than 160 papers, many of them seminal in her field.