The mode of reproduction seen in modern sharks is nearly 400 million years old. That is the conclusion drawn by Professor Per Erik Ahlberg, Uppsala University, from his discovery of a so-called "clasper" in a primitive fossil fish earlier this year. The research results are published today in Nature.

It comes as no surprise that some babies are more difficult to soothe than others but frustrated parents may be relieved to know that this is not necessarily an indication of their parenting skills. According to a new report in Psychological Science, a journal of the Association for Psychological Science, children's temperament may be due in part to a combination of a certain gene and a specific pattern of brain activity.

The National Oceanic and Atmospheric Administration (NOAA) today published a final rule in the Federal Register prohibiting the harvesting of krill in the Exclusive Economic Zone (EEZ) off the coasts of California, Oregon, and Washington. The rule goes into effect on August 12, 2009. Krill are a small shrimp-like crustacean and a key source of nutrition in the marine food web.

One of the continuing mysteries of the HIV/AIDS epidemic is why women usually develop lower viral levels than men following acute HIV-1 infection but progress faster to AIDS than men with similar viral loads. Now a research team based at the Ragon Institute of Massachusetts General Hospital (MGH), MIT and Harvard has found that a receptor molecule involved in the first-line recognition of HIV-1 responds to the virus differently in women, leading to subsequent differences in chronic T cell activation, a known predictor of disease progression. Their paper, which will be published in an upcoming issue of Nature Medicine, is receiving early online release.

When cells experiencing DNA damage fail to repair themselves, they send a signal to their neighbors letting them know they're in trouble. The discovery, which shows that a process dubbed the DDR (DNA Damage Response) also controls communication from cell to cell, has implications for both cancer and aging. The findings appear in the July 13 online edition of the Nature Cell Biology.

A study by scientists at Penn State provides new information about the genes that are involved in a mammal's early brain development, including those that contribute to neurological disorders. The study is the first to use high-throughput sequencing to uncover active genes in developing brains, and it is likely the best evidence thus far for the activity in the brain of such a large number of genes. The research results one day could lead to the development of drugs or gene therapies that treat neurological disorders such as autism and mental retardation. The research, which was led by Distinguished Professor of Biology Hong Ma and Associate Professor of Biology Gong Chen, will be published online in the Early Edition of the Proceedings of the National Academy of Sciences sometime during the week of 13 July 2009.

Why do some plants defend themselves from insect attacks better than others? New evidence shows that the difference might be due to whether they're getting any plant love.

HOUSTON – An iconic photograph (http://img.timeinc.net/time/80days/images/530228.jpg) of Nobel laureates Drs. Francis Crick and James Watson show the pair discussing with a rigid model of the famous double helix.

A new study of the cognitive processes involved with honesty suggests that truthfulness depends more on absence of temptation than active resistance to temptation.