SciTech Briefs

Plant ecologists study circadian rhythms

Circadian rhythms explain numerous biological processes in both animals and plants that arise in 24-hour cycles. Adding to this list, environmental scientists at Lancaster University report that circadian rhythms also influence the rate at which plants emit isoprene, an important chemical that reacts with nitrogen in the atmosphere to form one of the leading sources of ground-level ozone. The researchers also show that incorporating these body clock-influenced isoprene emission rates into atmospheric computer models improves ozone predictions.

Source: Nature Geoscience

Children act like scientists when they play

Four-year-olds use science, according to recent MIT research. In the experiments, children were shown how to activate a toy in one of two ways: Activating the toy by connecting its various parts was demonstrated in a straightforward way to some children, while the demonstration was ambiguous for other children. Those shown the ambiguous way of turning on the toy were frequently successful in doing so, while the other children did not experiment with the parts at all. The study concluded that young children seek information by experimenting when they are uncertain while playing, but not when games are straightforward or simple.

Source: Wired magazine

Paper receipts may contain carcinogens

Bisphenol A (BPA), a chemical known to cause cancer and disrupt reproductive systems, is commonly used to develop color in paper receipts. Over 80 receipts from seven U.S. cities were analyzed by the Wadsworth Center, a public health research center in New York. BPA absorbed through the skin travels directly into the bloodstream, while BPA that is ingested in food can be inactivated by metabolism. This finding is potentially significant, especially for bank tellers or other people who handle many receipts on a daily basis. Whether or not the BPA levels on receipts are enough to cause negative health effects is still unknown.

Source: Chemical & Engineering News

Eating chocolate found to be good for heart

British scientists recently gave the world another reason to consume chocolate: Eating chocolate is tied to lower risks of cardiovascular conditions, such as high blood pressure and strokes. The findings came from an analysis of seven previously conducted studies that included over 100,000 subjects. The team warned that even though chocolate may possibly improve health, overeating would cancel out these potential benefits. Risk of heart failure and diabetes were not found to be lowered by consuming chocolate.

Source: The New York Times

Crises in human history driven by climate change

What causes human crises such as war, epidemics, and population decline? Climate change, says a controversial study from a group of Chinese researchers. Statistical correlations between Northern Hemisphere temperatures and 14 agricultural, socioeconomic, and demographic variables (such as war fatalities, grain prices, number of plagues) were used to make the claim. The study was limited to the years 1500–1800 CE, so whether these results can be applied today, when scientific advances have decreased society’s sensitivity to climate, is unclear.

Source: Proceedings of the National Academy of Sciences

Hormone influencing obesity identified in mice

Mice lacking the hormone orexin were found to be obese, even when they ate less than a control group of mice with normal orexin levels, according to a new study from doctors at the Sanford-Burnham Medical Research Institute. An important type of cell that helps burn fat was found to be improperly developed in the orexin-lacking mice. “Without orexin, mice are permanently programmed to be obese,” said Devanjan Sikdar, the author of the study. The team plans to investigate next whether orexin might be used as a therapy to treat or prevent obesity.

Source: Los Angeles Times