Short periods of excercise may improve mood
A recent study found that short periods of moderate exercise can improve overall mood, increase vigor, and decrease fatigue. However, further improvement was not seen with longer workout sessions.
Science News for July 1, 2001
Teens' second pregnancy rates lower with long-term contraceptives
A study published in American Journal of Preventive Medicine found that long-term contraceptives, such as Norplant, reduced second pregnancy rates among teens. Among the participants who chose these methods, only 11% became pregnant within a year, compared to 25% of those using oral contraceptives and 38% of those not using birth control.
Emotional support keeps brain going into old age
A study found that emotional support was a significant predictor of better cognitive function in older adults, independent of other risk factors. Unmarried participants showed better cognitive function than married ones, suggesting that the presence of a spouse may have negative effects on cognition due to care burdens.
Kangaroo, platypus are not related after all; Duke scientists refute current molecular method of classifying mammals
Researchers at Duke University used nuclear genes to analyze genetic material from 15 mammal species, providing statistically unambiguous results in favor of the Theria hypothesis. This contradicts the Marsupionta hypothesis supported by mitochondrial DNA method, which links disparate animals like kangaroos and whales.