Bears don't rub trees because their backs are itchy. Dr Owen Nevin of the University of Cumbria states that adult male grizzly bears use so-called “rub trees” as a way to communicate with each other while looking for breeding females, and that this behavior could help reduce battles between the bears.

Many theories have been advanced as to why bears rub trees: some thought females might rub trees as they came into oestrous, and others that bears might be giving their backs a good scratch to get rid of parasites or pick up sap to act as insect repellent.

252 million years ago a mass extinction of cataclysmic proportions occurred and the world was changed forever. Prior to that, ocean life was diverse and clam-like organisms called brachiopods dominated. After the extinction little else existed and a different kind of clam-like organism, called a bivalve, took over.

Why did it happen?

Researchers at UT Southwestern Medical Center have found that a single gene might control whether or not individuals tend to pile on fat, a discovery that may point to new ways to fight obesity and diabetes.

“From worms to mammals, this gene controls fat formation,” said Dr. Jonathan Graff, associate professor of developmental biology and internal medicine at UT Southwestern and senior author of a study appearing in the Sept. 5 issue of Cell Metabolism.

Eminem should be reading up on his Elvis history if he wants to stay around. Famous musicians are more than twice as likely as the rest of the population to die an early death, and within a few years of becoming famous, reveals research in the Journal of Epidemiology and Community Health.

The findings are based on more than 1050 North American and European musicians and singers who shot to fame between 1956 and 1999.

Education is one of the rare industries with a powerful union, no incentive based pay and where generally the worst performers get more money yet is still regarded as not very good.

Improving education most would start with incentives for teachers, claims new findings by economics professors at the University of Missouri-Columbia and Vanderbilt University. They say that states and school districts in the United States begin developing programs that examine the effects of linking teacher pay to student achievement.

The study was a collaborative effort between Michael J. Podgursky, professor of economics at Mizzou’s College of Arts and Science, and Matthew G. Springer, research assistant professor of public policy and education at Vanderbilt’s Peabody College.

A team of scientists from around the globe has determined that a drastic change in the climate of tropical Africa may have significantly driven early human evolution.

Among the findings: A transition from a long period of time (about 135,000 to 75,000 years ago) that included several extreme droughts to a stable, wetter climate may have stimulated the expansion and migration of early human populations.

The researchers studied lake cores from Lake Malawi, at the southern end of East Africa’s Rift Valley, and found that the megadroughts were some of tropical Africa’s driest periods in the last million years or more.

It's done - the independent sequence and assembly of the six billion base pairs from the genome of one person, Craig Venter of the J. Craig Venter Institute (JCVI), has been completed.

Two general versions of the human genome currently exist but those were a melding of DNA from various people. In the case of one version from Celera Genomics, it was a consensus assembly from five individuals, while a government-funded version was a haploid genome based on sequencing from a limited number of individuals.

It seems both versions greatly underestimated human genetic diversity.

Nothing starts a debate in the medical community like death. Abortion, euthanasia, capital punishment, all controversial subjects; three anesthesiologists and a medical ethicist tackle the last one in a commentary and two editorials published in September's Mayo Clinic Proceedings.

In a commentary column, David Waisel, M.D., an anesthesiologist practicing at Children's Hospital Boston, Harvard Medical School, asserts that it is time to reassess the AMA's position on this issue and allow doctors to participate in state-mandated executions to help provide the condemned a more humane path to death.

Dr. Waisel cites numerous details about the technical problems associated with lethal injection, the form of capital punishment most commonly used in the United States today. Dr.

Nutrients taken from avocados are able to thwart oral cancer cells, killing some and preventing pre-cancerous cells from developing into actual cancers, according to researchers at Ohio State University.

Researchers found that extracts from Hass avocados kill or stop the growth of pre-cancerous cells that lead to oral cancer. Hass avocados are year-round fruits known for their distinctive bumpy skin that turns from green to purplish-black as they ripen.

While there are more than 500 varieties of avocados grown worldwide, Hass avocados are the most readily available at supermarkets nationwide. Similar research has not been conducted on other varieties of avocados.

The findings are published online in the journal Seminars in Cancer Biology.

Lead author Steven M.