The holidays are challenging for most everyone's midsection but are they a factor in actual obesity rather than seasonal weight gain?   And are weekends just as detrimental?

Researchers at the University of Pittsburgh and Quinnipiac University say yes to both.  Even weekend eating patterns can have a significant impact.

J. Jeffrey Inman, a University of Pittsburgh professor of marketing and associate dean for research in the Joseph M. Katz Graduate School of Business, and coauthor Adwait Khare, Quinnipiac University professor of marketing, studied two years' worth of data on consumers' eating behavior and found that the quantity and quality of foods eaten during a meal and over the course of the day differs considerably on weekends and holidays.

AIDS researchers have for the first time demonstrated that human blood stem cells can be engineered into cells that can target and kill HIV-infected cells — a process that potentially could be used against a range of chronic viral diseases. The study, published today in PLoS ONE, demonstrates that human stem cells can be engineered into the equivalent of a genetic vaccine.

By Taking CD8 cytotoxic T lymphocytes — the "killer" T cells that help fight infection — from an HIV-infected individual, the researchers identified the molecule known as the T-cell receptor, which guides the T cell in recognizing and killing HIV-infected cells.

A political scientist from the University of Alberta has uncovered a dastardly ploy by the producers of Thomas and Friends, a popular children's TV show, to turn their innocent audience of youngsters into  socially intolerant conservatives. 

After analyzing 23 episodes of Thomas and Friends, a show about a train, his friends and their adventures on a fictional island, political scientist Shauna Wilton was able to identify themes that she believes are incompatible with the egalitarian world society her and her social scientist friends are planning for our children. 

In a recent Journal of the National Cancer Institute editorial, doctors expressed concern over the media's coverage of oncology research, citing examples of exaggerated fears, hopes, and a general lack of skepticism in the reporting. 

The editorial points, for example, to the misleading coverage of a New England Journal of Medicine study that documented the trial results of the new anti-cancer drug olaparib. One national news outlet claimed the drug "was the most important cancer breakthrough of the decade," but failed to note that the study was uncontrolled (so there is no way to know if the drug accounted for the findings), and very preliminary (it is not known if the findings will ever translate into longer life).

A new study appearing tomorrow in Earth and Planetary Science Letters rules out the possibility that the methane on Mars was delivered by meteorites, boosting the theory that life exists on the red planet.

Researchers had thought that meteorites might be responsible for Martian methane levels because when the rocks enter the planet's atmosphere they are subjected to intense heat, causing a chemical reaction that releases methane and other gases into the atmosphere.

However, the new study, by researchers from Imperial College London, shows that the volumes of methane that could be released by the meteorites entering Mars's atmosphere are too low to maintain the current atmospheric levels of methane. Previous studies have also ruled

If you start smoking cigarettes, chances are you'll become addicted. But that's only part of the story, according to new research published in Psychopharmacology.  After exposing rats to passive smoke and studying how their brains responded, the authors of the studies are suggesting that just being exposed to cigarette smoke may result in nicotine dependence.  

In a set of four experiments on male Wistar rats, researchers investigated whether rats exposed passively to tobacco smoke would become dependent on nicotine.  They specifically looked at how the rats' brains responded to being exposed to tobacco smoke and whether the rats displayed withdrawal symptoms.