A novel experiment conducted by Carnegie Mellon University Professor George Loewenstein and colleagues may explain why people try a drug, such as heroin, for the first time despite ample evidence that it is addictive. The results of the study, which are being published in the Journal of Health Economics, reveal that even longtime addicts underestimate the influence that drug cravings have over their behavior.

Almost all drugs produce a craving in their users. Loewenstein and his colleagues hypothesized that people experiment with drugs that they know are addictive in part because they can't appreciate the intensity of drug cravings, and thus underestimate the likelihood that they will become addicted.

Peering backward in time to an instant after the big bang, physicists at the University of Wisconsin-Madison have devised an approach that may help unlock the hidden shapes of alternate dimensions of the universe.

A new study demonstrates that the shapes of extra dimensions can be "seen" by deciphering their influence on cosmic energy released by the violent birth of the universe 13 billion years ago. The method, published today (Feb.

Portable inspection devices that detect food safety and quality problems are being developed by Agricultural Research Service (ARS) scientists. Recent food safety outbreaks highlight the need for "space-age" ways to prevent such problems at every step in the food production process -- from farm field to grocery store or restaurant.

Scientists led by Yud-Ren Chen at the ARS Instrumentation and Sensing Laboratory, Beltsville, Md., are designing such portable inspection devices by adapting optical technology used for remote sensing of Earth.

Prototypes include binoculars with lenses that detect fecal matter on meat, produce or processing equipment--as well as diseases or quality defects.

A giant cloud half the size of the United States has been imaged on Saturn’s moon Titan by the Cassini spacecraft. The cloud may be responsible for the material that fills the lakes discovered last year by Cassini's radar instrument.

Cloaked by winter's shadow, this cloud has now come into view as winter turns to spring. The cloud extends down to 60 degrees north latitude, is roughly 2400 kilometers in diameter and engulfs almost the entire north pole of Titan.

The new image was acquired on 29 December 2006, by Cassini's visual and infrared mapping spectrometer (VIMS).

A little-known lipid plays a big role in helping us grow from a hollow sphere of stem cells into human beings, researchers have found.

They found that in the first few days of life, ceramide helps stem cells line up to form the primitive ectoderm from which embryonic tissues develop, says Dr. Erhard Bieberich, biochemist at the Medical College of Georgia.

Probably 90 percent of ceramide gathers at the top or apical end of these early stem cells, literally helping cells have direction. “We have cell polarity, an up and down, a head and foot of the cell, and that is what ceramide most likely regulates,” says Dr. Bieberich.