Ngnochannel array glass

The fabrication and characterization of a glass containing a regular parallel array of submicrometer channels or capillaries are described. The capillaries are arranged in a two-dimensional hexagonal close packing configuration with channel diameters as small as 33 nanometers and packing densities as high as 3 x 10(10) channels per square centimeter. The high-temperature stability of the nanochannel glass array is well suited as a host or template for the formation of quantum confined semiconductor structures or as a mask for massively parallel patterned lithographic applications.     

Frequent recombination in a saltern population of Halorubrum

Sex and recombination are driving forces in the evolution of eukaryotes. Homologous recombination is known to be the dominant process in the divergence of many bacterial species. For Archaea, the only direct evidence bearing on the importance or natural occurrence of homologous recombination is anecdotal reports of mosaicism from comparative genomic studies. Genetic studies, however, reveal that recombination may play a significant role in generating diversity among members of at least one archaeal group, the haloarchaea. We used multi-locus sequence typing to demonstrate that haloarchaea exchange genetic information promiscuously, exhibiting a degree of linkage equilibrium approaching that of a sexual population.     

Venus: preliminary topographic and surface imaging results from the pioneer orbiter

Three large Venus surface features, identified previously in images obtained from Earth-based radar observations, are shown by the Pioneer Venus radar mapper to be elevated 5 to 10 kilometers above the surrounding terrain. Two of these features, one bright and the other dark, lie adjacent to each other astride the 65 degrees N parallel between longitudes 310 degrees E and 10 degrees E. The combined region forms a huge tectonically uplifted plateau, surmounted by radar-bright ridges that may have either a volcanic or tectonic origin. The third feature, located at 30 degrees N, 283 degrees E, is radar-bright and may consist of volcanic material extruded along a fault zone. A first radar-scattering image, compiled from data obtained by the mapper in its imaging mode, shows a region north of the equator; several circular depressions seen in this area may result from meteoritic impact.     

Reclamation of Fine Fraction Bauxite Processing Residue (Red Mud) Amended with Coarse Fraction Residue and Gypsum

Establishment of vegetation on residues produced from the bauxite refining process is a beneficial part of their environmental management. Of the two fractions produced in the refining, the coarse fraction has greater efficiency in the leaching of excess salts and alkalinity. However, these same properties can result in increased loss of nutrients and low water-holding capacity. The current study investigated the use of mixing coarse fraction residue with fine fraction residue, at two different application rates (10% and 25%), with and without the use of gypsum as an ameliorant, for re-vegetation of the residue with Trifolium pratense. Optimum plant growth was observed in treatments that had also received gypsum amendment, with higher plant biomass, Mn nutrition and lower Al and Fe concentration. However, use of process sand at the higher application rate (25%) promoted lower levels of soluble Al and Fe and exchangeable Na in the substrate and, consequently, lower plant uptake of Na. Results indicate that co-disposal of the coarse fraction sand at 25% w/w with fine fraction residue can improve the substrate and, therefore, plant uptake and growth. Further monitoring is recommended to determine the effect of the absence of gypsum and other nutrient sources on plant growth.     

Iodine content of commercially-prepared cat foods

Twenty-eight varieties of commercially-available cat food (23 canned, 5 dried) were analysed for iodine. The iodine concentration varied from less than 0.37 micromol/kg to 41.8 pmol/kg, wet weight (less than 1.48 micromol/kg to 167 micromol/kg, dry weight). Excessive or insufficient iodine intake or wide swings in iodine intake over prolonged periods may contribute to thyroid disorders in cats.     

Landscape,fire and habitat: which features of recently burned heathland influence site occupancy of an early successional specialist?

Context

Multiple ecological drivers generate spatial patterns in species’ distributions. Changes to natural disturbance regimes can place early successional habitat specialists at an increased risk of extinction by altering landscape patterns of habitat suitability.

Objectives

We developed a series of hypotheses to evaluate the effects of landscape structure, fire history, and site-level habitat quality on site occupancy by an early successional specialist, the eastern chestnut mouse (Pseudomys gracilicaudatus).

Methods

We obtained eight years of monitoring data from 26 sites in recently burned heathland in southeast Australia. We used generalised linear models to determine which explanatory variables were related to occupancy. We also explored predictability in patterns of small mammal species co-occurrence.

Results

Landscape structure (patch area, landscape heterogeneity) was strongly related to site occupancy. Site occupancy was associated with dead shrubs in the understory and rock cover on ground layer, but was not directly influenced by recent or historical fire. Contrary to contemporary ecological theory, we found no predictable species associations in our early successional community.

Conclusions

We recommend surveys take account of landscape configuration and proximity to suitable habitat for optimal results. Fire regimes expected to promote eastern chestnut mouse population growth should encourage the retention of critical habitat features rather than be based on temporal rates of successional stages. For management to adequately account for post-disturbance patterns in early successional communities, a species-by-species, multi-scaled approach to research is necessary.

     

Onchocerca gutturosa and Onchocerca lienalis in cattle: variation in length of microfilariae by site of recovery

Dermal microfilariae recovered from specimens obtained from umbilical and cervical sites of cattle infected with adult Onchocerca gutturosa alone or with adults of O gutturosa and O lienalis were measured and compared with uterine microfilariae obtained directly from gravid female worms of each species. Uterine microfilariae of O gutturosa were longer than dermal microfilariae obtained from cattle harboring only adults of O gutturosa. Dermal microfilariae were recovered from umbilical and cervical sites in these cattle. Those found at the cervical site had lengths equal to or greater than lengths of microfilariae recovered from the umbilical site. There was a significant (P less than 0.0001) shift in length across populations of microfilariae of O gutturosa from various sites in its bovine host, with a progressive decrease in length between microfilariae recovered from the worm's uterus, microfilariae from the cervical dermis, and microfilariae from the umbilical dermis, respectively. A similar direct comparison was not possible for microfilariae of O lienalis, because none of the cattle was infected with only adult worms of this species. In an indirect comparison, microfilariae of O lienalis were identified at the umbilicus, but their presence in the cervical region could not be determined unequivocally because of confounding of microfilariae length by concurrent infection with O gutturosa. Uterine microfilariae from O lienalis were longer than uterine microfilariae of O gutturosa, although a degree of overlap in the range of measurements existed between species.