The pick of the science news
Memory carbs
Low-carbohydrate diets can lead to fuzzy thinking. In a new study, dieters who left carbohydrates out of their meals performed less well in memory-based tasks than when they reduced calories but maintained carbohydrates. When carbohydrates were reintroduced, cognition skills returned to normal.
"The data suggest that after a week of severe carbohydrate restriction, memory performance, particularly on difficult tasks, is impaired," says Holly A Taylor, professor of psychology at Tufts University in Massachusetts, who led the research on 19 people. "Although this study only tracked dieting participants for three weeks, the data suggest that diets can affect more than just weight."
Hard facts on soft drinks
Fruit-derived drinks could contain relatively high levels of pesticide residues, according to new research from Spain. Residues on fresh fruit and vegetables get plenty of attention, but this was the first worldwide study of pesticides in fruit-based soft drinks, according to its authors, who used chemical analysis to screen branded products from 15 countries.
"Concentration levels detected were of the micrograms-per-litre level, low when considering the European maximum residue levels (MRLs) set for fruits but very high when considering the MRLs for drinking or bottled water," write the researchers in Analytical Chemistry. "Steps should be taken with the aim of removing any traces of pesticides in these products."
By numbers
70,000
The age in years of stone tools found in Syria. It is believed that Neanderthals made them by sticking sharpened stones to handles with bitumen
1,068
The number of newly discovered species in the Greater Mekong region between 1997 and 2007, according to the World Wildlife Fund. Finds included a spider as large as a dinner plate and a rat thought to have died out 11 million years ago.
Claire O'Connell
e-mail: 1000.claire@gmail.com