Cold tolerance and water content of current-year red spruce foliage over two winter seasons

Red spruce (Picea rubens Sarg.) in high elevation forests of northeastern North America suffers from frequent and severe winter injury, leading to apical dieback, decreased growth, and high mortality. To examine the role of winter desiccation and freezing injury in winter damage, weekly assessments of cold tolerance and water content were made on current-year foliage collected from native red spruce trees at a high elevation site over two winter seasons. In both years, foliage maintained high water contents and adequate cold tolerance; nonetheless, slight to moderate injury was observed each year on some trees. Despite brief thaw periods each winter, no mid-winter dehardening sufficient to put foliage at risk of freezing injury was evident. These findings suggest that, at least in some years, winter injury to current-year red spruce foliage is produced by a mechanism other than desiccation or absolute low temperatures.     

Minimum condition for stereopsis and anomalous contour

Horizontal borders were deleted progressively from square and circular dot patterns containing disparate forms. Stereoscopic depth and anomalous contour occur in the absence of horizontal borders and the form in depth does not always assume the shape of the dot patterns. The stereoscopic effects depend on a laterally disparate form in the stereogram.     

Identification of a ventral scent marking pheromone in the male Mongolian gerbil (Meriones unguiculatus)

Sebum from the ventral scent marking gland of the male Mongolian gerbil was fractionated and tested for its ability to elicit behavioral response in a conditioning task and in a stimulus preference situation. The active fraction was identified as phenylacetic acid; both it and a synthetic sample elicited the same behavioral response. Phenylacetic acid appears to be a major pheromone of the male Mongolian gerbil.     

Global distribution of neutrons from Mars: results from Mars odyssey

Global distributions of thermal, epithermal, and fast neutron fluxes have been mapped during late southern summer/northern winter using the Mars Odyssey Neutron Spectrometer. These fluxes are selectively sensitive to the vertical and lateral spatial distributions of H and CO2 in the uppermost meter of the martian surface. Poleward of +/-60 degrees latitude is terrain rich in hydrogen, probably H2O ice buried beneath tens of centimeter-thick hydrogen-poor soil. The central portion of the north polar cap is covered by a thick CO2 layer, as is the residual south polar cap. Portions of the low to middle latitudes indicate subsurface deposits of chemically and/or physically bound H2O and/or OH.     

Genome sequence of Aedes aegypti, a major arbovirus vector

We present a draft sequence of the genome of Aedes aegypti, the primary vector for yellow fever and dengue fever, which at approximately 1376 million base pairs is about 5 times the size of the genome of the malaria vector Anopheles gambiae. Nearly 50% of the Ae. aegypti genome consists of transposable elements. These contribute to a factor of approximately 4 to 6 increase in average gene length and in sizes of intergenic regions relative to An. gambiae and Drosophila melanogaster. Nonetheless, chromosomal synteny is generally maintained among all three insects, although conservation of orthologous gene order is higher (by a factor of approximately 2) between the mosquito species than between either of them and the fruit fly. An increase in genes encoding odorant binding, cytochrome P450, and cuticle domains relative to An. gambiae suggests that members of these protein families underpin some of the biological differences between the two mosquito species.