That cold feeling-it’s liquor

That cold feeling—it’s liquor
Many believe that drinking makes you warmer in winter. In moderation, the right beverage can bring cheer on a cold winter night, but does it really warm you up? According to studies over the years, while alcohol may seem like the perfect cold-weather beverage because it creates a sensation of warmth, it actually decreases core body temperature—regardless of the temperature outside—and increases the risk of hypothermia. The normal process that makes us feel cold occurs when blood flows away from the skin and into the organs, which increases core body temperature. Alcohol reverses this process, increasing the flow of blood to the skin and setting off a sharp drop in body temperature. It also reverses other reflexes that control body temperature. Another study, published in 2005, found that after a single drink, the body tries to counteract the brief sensation of warmth caused by increased blood flow to the skin by ramping up its rate of sweating, which only decreases body temperature even further. This may not sound like much. But several studies have found that alcohol ingestion often plays a role in hypothermia-related injuries and deaths.

Secret of ant’s success: diet
The Argentine ant is a very successful invasive species, having conquered territories far from its native South America. Once introduced, inadvertently, by people, it marches across the landscape, displacing local ant species and making an agricultural pest of itself. Researchers from the University of Illinois and the University of California, San Diego, have uncovered one secret to the ant’s success: dietary flexibility. The insects can live high on the hog, but will eat at lower levels of the food chain if they have to. Chadwick V. Tillberg and colleagues studied an invasion of ants across a canyon in Chula Vista, California, over eight years. They collected ants at various sites and analysed the ratio of stable nitrogen isotopes in the insects, an indication of what they were eating.
As the researchers report in The Proceedings of the National Academy of Sciences, ants right at the invasion front showed higher levels of nitrogen-15, suggesting they were consuming native ants and other insects. But as the front moved on, nitrogen-15 levels declined, with the ants switching to food from plants, particularly the honeydew produced by aphids. The researchers also compared isotope levels between ants in California and in their native Argentina and found that the native ants ate higher on the food chain. Taken together, the researchers say, the findings support the idea that a flexible diet makes for a successful invasion.

Spotting sharks, stripe by stripe
Facial recognition software holds great promise, but the jury is still out on how effective it is now. The software, which compares patterns from an electronic image of a face to a database of images, hasn’t proved particularly good at picking criminals out of a crowd, for instance. But an Australian scientist is having better luck with software that can identify individual whale sharks. It doesn’t analyse shark faces, rather individual patterns of spots and stripes on the fish’s skin. Bradley Norman of Murdoch University in Perth worked with a computer programmer, Jason Holmberg, and a NASA scientist, Zaven Arzoumanian, to adapt software originally developed for telescopes to recognise patterns of stars and other celestial objects. Using thousands of photos submitted by researchers and others through a conservation organisation, Ecocean, founded by Dr. Norman, the researchers were able to identify individual sharks around Ningaloo reef in western Australia, a prime sighting area for these huge fish. In a paper to be published this month in the journal Ecological Applications, the researchers report repeat sightings of many individual sharks from year to year, suggesting that the shark population is healthy. (nyt)