Littered with the dehydrating corpses of seaweeds, beaches after a big storm are a reminder that life can be tough out there in the crashing waves. But seaweeds aren’t totally defenseless. A recent study in the American Journal of Botany studied two different strategies that seaweeds use to reduce drag so that fast-moving waves don’t uproot them.
Drag is proportional to the total area of the seaweed multiplied by drag coefficient, which depends on the seaweed’s shape. (For example, a boxy school bus has a higher drag coefficient than a race car.) That means seaweeds can either get smaller or more streamlined to ride out the waves.
Red is not a proxy signal for female genitalia in humans.
“Red is a colour that induces physiological and psychological effects in humans, affecting competitive and sporting success, signalling and enhancing male social dominance. The colour is also associated with increased sexual attractiveness, such that women associated with red objects or contexts are regarded as more desirable. It has been proposed that human males have a biological predisposition towards the colour red such that it is ‘sexually salient’. This hypothesis argues that women use the colour red to announce impending ovulation and sexual proceptivity, with this functioning as a proxy signal for genital colour, and that men show increased attraction in consequence. Read the rest of this entry »
Female chimpanzees use copulation calls flexibly to prevent social competition.
“The adaptive function of copulation calls in female primates has been debated for years. One influential idea is that copulation calls are a sexually selected trait, which enables females to advertise their receptive state to males. Male-male competition ensues and females benefit by getting better mating partners and higher quality offspring. We analysed the copulation calling behaviour of wild female chimpanzees (Pan troglodytes schweinfurthii) at Budongo Forest, Uganda, but found no support for the male-male competition hypothesis. Read the rest of this entry »
“STUDY OBJECTIVES: Sleep loss consistently impairs performance on measures of alertness, vigilance, and response speed, but its effects on higher-order executive functions are not well delineated. Similarly, whereas deficits in arousal and vigilance can be temporarily countered by the use of several different stimulant medications, it is not clear how these compounds affect complex cognitive processes in sleep-deprived individuals. DESIGN: We evaluated the effects of double-blind administration of 3 stimulant medications or placebo on the ability to appreciate humor in visual (cartoons) or verbal (headlines) stimuli presented on a computer screen following 49.5 hours of sleep deprivation. Read the rest of this entry »
Physical properties and microstructural changes during soaking of individual corn and quinoa breakfast flakes.
“The importance of breakfast cereal flakes (BCF) in Western diets deserves an understanding of changes in their mechanical properties and microstructure that occur during soaking in a liquid (that is, milk or water) prior to consumption. The maximum rupture force (RF) of 2 types of breakfast flaked products (BFP)–corn flakes (CF) and quinoa flakes (QF)–were measured directly while immersed in milk with 2% of fat content (milk 2%) or distilled water for different periods of time between 5 and 300 s. Read the rest of this entry »
A dentist will tell you to floss everyday, but an archeologist might, well, have different priorities. Turns out the nitrogen and carbon isotopes in dental plaque can give archeologists a look at 1,000-year-old diets.
The buildup of plaque on this set of teeth is, um, impressive. (Cut the skull some slack though, this was before we had dentists to chide us about daily flossing.) Without the benefit of modern dental hygiene, the plaque built up over a lifetime, layer upon layer like a stalagmite. In a paper recently published in the Journal of Archeological Science researchers exhumed 58 medieval Spanish skeletons and scraped off their dental plaque to test carbon and nitrogen isotopes. When they compared the isotope profiles of the Spaniards to that of plaque from an Alaskan Inuit, the scientists found the ratio of nitrogen-15 to be quite different. That makes sense, as the Intuit ate a predominantly marine diet, and there is more nitrogen-15 in the protein molecules of organisms living in sea than on land.
“The evolutionary origins of music are much debated. One theory holds that the ability to produce complex musical sounds might reflect qualities that are relevant in mate choice contexts and hence, that music is functionally analogous to the sexually-selected acoustic displays of some animals. If so, women may be expected to show heightened preferences for more complex music when they are most fertile. Read the rest of this entry »
“Whether erotic films made by women are more arousing for women than erotic films made by men was studied. Forty-seven subjects were exposed to both a woman-made, female-initiated, and female centered, erotic film excerpt. Photoplethysmographic vaginal pulse amplitude was recorded continuously. Self-report ratings of sexual arousal and affective reactions were collected after each stimulus presentation. Read the rest of this entry »
Bees perceive illusory colours induced by movement.
“Certain black-and-white patterns, when rotated at appropriate speeds, can create the artificial perception of hues. We report that this illusion is not confined to human vision, but is also perceived by an insect, the honeybee. The findings suggest that certain features underlying the processing of colour information are shared by man and bee.”
Discoblog is DISCOVER's compendium of quirky, funny, and surprising science news from the edge of the known universe. It's written by Veronique Greenwood and Valerie Ross. Email tips and suggestions to vgreenwood [at] discovermagazine [dot] com.
