NEAR at eros: imaging and spectral results

Eros is a very elongated (34 kilometers by 11 kilometers by 11 kilometers) asteroid, most of the surface of which is saturated with craters smaller than 1 kilometer in diameter. The largest crater is 5.5 kilometers across, but there is a 10-kilometer saddle-like depression with attributes of a large degraded crater. Surface lineations, both grooves and ridges, are prominent on Eros; some probably exploit planes of weakness produced by collisions on Eros and/or its parent body. Ejecta blocks (30 to 100 meters across) are abundant but not uniformly distributed over the surface. Albedo variations are restricted to the inner walls of certain craters and may be related to downslope movement of regolith. On scales of 200 meters to 1 kilometer, Eros is more bland in terms of color variations than Gaspra or Ida. Spectra (800 to 2500 nanometers) are consistent with an ordinary chondrite composition for which the measured mean density of 2.67 +/- 0.1 grams per cubic centimeter implies internal porosities ranging from about 10 to 30 percent.     

Control of a mucosal challenge and prevention of AIDS by a multiprotein DNA/MVA vaccine

Heterologous prime/boost regimens have the potential for raising high levels of immune responses. Here we report that DNA priming followed by a recombinant modified vaccinia Ankara (rMVA) booster controlled a highly pathogenic immunodeficiency virus challenge in a rhesus macaque model. Both the DNA and rMVA components of the vaccine expressed multiple immunodeficiency virus proteins. Two DNA inoculations at 0 and 8 weeks and a single rMVA booster at 24 weeks effectively controlled an intrarectal challenge administered 7 months after the booster. These findings provide hope that a relatively simple multiprotein DNA/MVA vaccine can help to control the acquired immune deficiency syndrome epidemic.     

Avian community response to pine flatwoods management

Across the southeastern United States, changing disturbance regimes threaten the integrity of pine flatwoods, reducing their suitability as habitat for a variety of avian species, many of which are considered of conservation priority. Prescribed burning and roller chopping are management practices widely used in pine flatwoods to control shrubs and increase the growth of herbaceous vegetation. However, the impacts these treatments have on this system and its associated avian communities are largely unknown. We examined the effects of prescribed burning and roller chopping on pine flatwoods avian communities using a paired sample approach. Avian communities were compared between treated (e.g., burned) and untreated areas. We considered abundance and richness of all birds, but also groups of conservation concern, and those likely impacted by seasonal management practices (e.g., breeding and non-breeding categories, and woodland, successional-scrub, and grassland guilds). Dormant season burning resulted in decreases in avian species richness and abundance within the non-breeding, overwintering community. In situations where the maintenance or enhancement of this avian group is desired, growing season burning appears beneficial and should be used in preference to dormant season burning. Growing season burning benefited breeding avian communities, resulting in increases in species richness and abundance within this group. Dormant season roller chopping had no effect on species richness or abundance of any avian category or guild. Increases in abundance within breeding avian communities were observed following growing season roller chopping and a roller chopping/burning combination. Grazing, did not mediate the effects of prescribed burning or roller chopping on avian species richness or abundance. The use of dormant season burning is likely inappropriate in situations where conservation and management of non-breeding, overwintering species is a priority. The use of growing season roller chopping appears to provide a potential treatment alternative in situations where positive effects on breeding species are desired. Overall, maintenance of avian abundance and richness may be best achieved through the diverse application of prescribed burning and roller chopping based on season, frequency, and space.     

Direct liquid chromatography method for the simultaneous quantification of hydroxytyrosol and tyrosol in red wines

A validated HPLC method with fluorescence detection for the simultaneous quantification of hydroxytyrosol and tyrosol in red wines is described. Detection conditions for both compounds were optimized (excitation at 279 and 278 and emission at 631 and 598 nm for hydroxytyrosol and tyrosol, respectively). The validation of the analytical method was based on selectivity, linearity, robustness, detection and quantification limits, repeatability, and recovery. The detection and quantification limits in red wines were set at 0.023 and 0.076 mg L(-1) for hydroxytyrosol and at 0.007 and 0.024 mg L(-1) for tyrosol determination, respectively. Precision values, both within-day and between-day (n = 5), remained below 3% for both compounds. In addition, a fractional factorial experimental design was developed to analyze the influence of six different conditions on analysis. The final optimized HPLC-fluorescence method allowed the analysis of 30 nonpretreated Spanish red wines to evaluate their hydroxytyrosol and tyrosol contents.     

More superconductivity questions than answers

Although making liquid nitrogen-temperature superconductors is easy enough that high school science projects already feature them, researchers still have little idea how the new ceramic oxides work and therefore little guidance for improving them. At the International Workshop on Novel Mechanisms of Superconductivity, held from 22 to 26 June in Berkeley, California, theorists reviewed a host of competing explanations of how these materials come by their remarkable properties, but they could not, get far in sifting through the candidates for the best one. One cause of the unsettled situation is that theorists have not yet pushed their models far enough to make many specific predictions about physical properties and therefore to provide a reason to choose one theory over another. But experimental data for comparison with theory are lacking, too. For example, experimentalists are just now succeeding in being able to grow single crystals and thin films of the ceramic oxide superconductors, whose properties were shown at the workshop to be highly anisotropic. Measurements already made on the polycrystalline sintered material available up to now are difficult to interpret and therefore need to be repeated on good-quality crystals and films, where the variation of properties with crystallographic orientation can be mapped out. Given the high level of Japanese activity in the field, it was surprising that no researchers from industrial laboratories in Japan presented their findings at the workshop. In the light of a budding international competition in commercializing superconductors, some American scientists interpreted the absence as an attempt to protect proprietary advances. A more pleasant surprise was the attendance of a delegation of six Soviet scientists, although one of the fathers of superconductivity theory, Vitaly Ginzburg of the P.N.Lebedev Institute of Physics in Moscow, who was expected, did not come.