Enduring effects of photoperiod on affective behaviors in Siberian hamsters (Phodopus sungorus).

The effects of perinatal and postweaning photoperiods on subsequent affective behaviors were examined in adult Siberian hamsters (Phodopus sungorus). Hamsters exposed perinatally to short days (8 hr light/day) exhibited mixed results for adult anxiety-like behaviors and increased some depressive-like behaviors compared with hamsters exposed to long days (16 hr light/day). Postweaning exposure to short days increased depressive- and anxiety-like behaviors compared with long days. Sex differences in affective behaviors were observed. These results suggest that anxiety-like behaviors are organized early in life and endure throughout adulthood, and anxiety- and depressive-like behaviors are modified by postweaning photoperiod. The persistence of photoperiod-induced affective behaviors in rodents supports the hypothesis that symptoms of human affective disorders may reflect ancestral adaptations to seasonal environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory and aging: The role of retrieval processes.

A review of the literature demonstrates that production deficiency hypotheses are unable to account fully for the fact that older adults perform more poorly on memory tasks than young adults. The possibility is explored that age-related differences are due to changes in fundamental processes involved in retrieval of information from memory, namely, (a) utilization of contextual information and (b) activation processes occurring in semantic memory. Automatic as well as intentional processes are examined. (5? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resistance transfer fecal coliforms isolated from the whippany river

Three sites on the Whippany River, a tributary of the Passaic Watershed in Morris County, N.J., were monitored for resistance transfer coliforms. A high percentage of fecal coliform isolates showed multiple antibiotic resistance. A significant number of lac⁻ and lac⁻ isolates proved to be donors of transmissible antibiotic resistance plasmids (R donors), by conjugation with a recipient strain of Salmonella gallinarum. Re-examination of testing methods used for recreational and potable water sources is suggested by these findings.     

Molecular-level description of proteins from saccharomyces cerevisiae using quadrupole FT hybrid mass spectrometry for top down proteomics

For improved detection of diverse posttranslational modifications (PTMs), direct fragmentation of protein ions by top down mass spectrometry holds promise but has yet to be achieved on a large scale. Using lysate from Saccharomyces cerevisiae, 117 gene products were identified with 100% sequence coverage revealing 26 acetylations, 1 N-terminal dimethylation, 1 phosphorylation, 18 duplicate genes, and 44 proteolytic fragments. The platform for this study combined continuous-elution gel electrophoresis, reversed-phase liquid chromatography, automated nanospray coupled with a quadrupole-FT hybrid mass spectrometer, and a new search engine for querying a custom database. The proteins identified required no manual validation, ranged from 5 to 39 kDa, had codon biases from 0.93 to 0.083, and were primarily associated with glycolysis and protein synthesis. Illustrations of gene-specific identifications, PTM detection and subsequent PTM localization (using either electron capture dissociation or known PTM data stored in a database) show how larger scale proteome projects incorporating top down may proceed in the future using commercial Q-FT instruments.     

Effects of superabsorbent polyacrylamides on efficiency of water use by crop seedlings

Cross-linked polyacrylamide expands upon contact with water to form a pliable gel that in a growing medium constitutes a reservoir of moisture available for uptake by plants. Trials with seedlings of three crop species (Lactuca sativa L, Raphanus sativus L, Triticum aestivum L) using measurements of yield and evapotranspiration ratio show that gel-stored moisture is utilised with a greater efficiency than conventional forms of water. Moreover, gel storage of water provides a buffer against temporary drought stress and the potential for reducing the risk of failure of certain crops at establishment.     

Electrochemical reduction of hexahydro-1,3,5-trinitro-1,3,5-triazine in aqueous solutions

Electrochemical reduction of RDX, hexahydro-1,3,5-trinitro-1,3,5-triazine, a commercial and military explosive, was examined as a possible remediation technology for treating RDX-contaminated groundwater. A cascade of divided flow-through cells was used, with reticulated vitreous carbon cathodes and IrO2/Ti dimensionally stable anodes, initially using acetonitrile/water solutions to increase the solubility of RDX. The major degradation pathway involved reduction of RDX to the corresponding mononitroso compound, followed by ring cleavage to yield formaldehyde and methylenedinitramine. The reaction intermediates underwent further reduction and/or hydrolysis, the net result being the complete transformation of RDX to small molecules. The rate of degradation increased with current density, but the current efficiency was highest at low current densities. The technique was extended successfully both to 100% aqueous solutions of RDX and to an undivided electrochemical cell.     

Minimizing the maximum starting time on-line

We study the scheduling problem of minimizing the maximum starting time on-line. The goal is to minimize the last time that a job starts. We show that while the greedy algorithm has a competitive ratio of Θ (log m), we can give a constant competitive algorithm for this problem. We also show that the greedy algorithm is optimal for resource augmentation in the sense that it requires 2m − 1 machines to have a competitive ratio of 1, whereas no algorithm can achieve this with 2m − 2 machines.     

Electrochemical Chromium(III) Oxide Coatings on Non-oxide Ceramic Substrates

SiC and TiB₂ were electrochemically coated with Cr₂O₃ from a 0.1 M aqueous solution of chromium nitrate hydrate with ethanol additives. On both substrate materials poly-crystalline Cr₂O₃ was formed at current densities from 5 to 50 mA/cm² and deposition durations of 5 to 30 min. The coating weight increased with current density and with deposition time. The as-deposited coatings contained microcracks due to drying shrinkage. Microstructural observations indicate that sintering of the Cr₂O₃ coatings on TiB₂ at 1100°C for 1 n in a reducing atmosphere in a closed graphite crucible causes the densification of the coating via a liquid phase, which forms by oxidation of TiB₂. Under similar conditions, the Cr₂O₃ coatings on SiC may be sintered via an evaporation–condensation mechanism.     

Heterogeneous Reactions of Chlorine Nitrate and Dinitrogen Pentoxide on Sulfuric Acid Surfaces Representative of Global Stratospheric Aerosol Particles

Increasing evidence from field measurements, modeling studies, and laboratory experiments suggests that heterogeneous reactions on stratospheric sulfate aerosol particles can change the partitioning in the nitrogen and chlorine families and thereby affect global ozone levels. In this study, a Knudsen cell flow reactor was used to measure the uptake of ClONO₂ and N₂O₅ by sulfuric acid solutions representative of background and volcanic stratospheric aerosol particles. The uptake coefficient (γ) of chlorine nitrate on 50–75 wt% H₂SO₄ at 223 K was found to be markedly dependent on the acid concentration, with γ ranging from about 1 × 10⁻² to 1 × 10⁻⁴. These results are in good agreement with literature reports and the data fit the expression log γ= 1.87 – 0.074 × (wt% H₂SO₄). This reaction will thus have its largest impact when stratospheric temperatures are low and sulfuric acid aerosols are most dilute. Uptake of N₂O₅ was studied on solutions with compositions in the range 58–96 wt% H₂SO₄ at temperatures from 193 to 303 K. N₂O₅ reacted readily on sulfuric acid surfaces with uptake coefficients of about 0.06. The uptake coefficient was found to be independent of the sulfuric acid concentration and the solution temperature over the ranges studied. These results suggest that the reaction of N₂O₅ with H₂O will occur readily on sulfuric acid aerosol particles for most stratospheric conditions.