Insect Pheromones and Precursors in Female African Elephant Urine

Using automated solid-phase dynamic extraction and gas chromatography-mass spectrometry, our search for urinary chemical signals from ovulatory female African elephants (Loxodonta africana) has revealed the bark beetle aggregation pheromones frontalin, exo-brevicomin, and endo-brevicomin, as well as their precursors and the aphid alarm pheromones (E,E)-alpha-farnesene and (E)-beta-farnesene. Enantiomeric ratios for brevicomins have been determined. Prior discovery of common insect/elephant pheromones in Asian elephants, namely, (Z)-7-dodecenyl acetate and frontalin, suggests that the present findings may yield valuable insights into chemical communication among African elephants.     

Evidence for organosulfates in secondary organic aerosol

Recent work has shown that particle-phase reactions contribute to the formation of secondary organic aerosol (SOA), with enhancements of SOA yields in the presence of acidic seed aerosol. In this study, the chemical composition of SOA from the photooxidations of alpha-pinene and isoprene, in the presence or absence of sulfate seed aerosol, is investigated through a series of controlled chamber experiments in two separate laboratories. By using electrospray ionization-mass spectrometry, sulfate esters in SOA produced in laboratory photooxidation experiments are identified for the first time. Sulfate esters are found to account for a larger fraction of the SOA mass when the acidity of seed aerosol is increased, a result consistent with aerosol acidity increasing SOA formation. Many of the isoprene and alpha-pinene sulfate esters identified in these chamber experiments are also found in ambient aerosol collected at several locations in the southeastern U.S. It is likely that this pathway is important for other biogenic terpenes, and may be important in the formation of humic-like substances (HULIS) in ambient aerosol.     

Measurements of isoprene-derived organosulfates in ambient aerosols by aerosol time-of-flight mass spectrometry - part 1: single particle atmospheric observations in Atlanta

Organosulfate species have recently been identified as a potentially significant class of secondary organic aerosol (SOA) species, yet little is known about their behavior in the atmosphere. In this work, organosulfates were observed in individual ambient aerosols using single particle mass spectrometry in Atlanta, GA during the 2002 Aerosol Nucleation and Characterization Experiment (ANARChE) and the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS). Organosulfates derived from biogenically produced isoprene were detected as deprotonated molecular ions in negative-ion spectra measured by aerosol time-of-flight mass spectrometry; comparison to high-resolution mass spectrometry data obtained from filter samples corroborated the peak assignments. The size-resolved chemical composition measurements revealed that organosulfate species were mostly detected in submicrometer aerosols and across a range of aerosols from different sources, consistent with secondary reaction products. Detection of organosulfates in a large fraction of negative-ion ambient spectra - ca. 90-95% during ANARChE and ~65% of submicrometer particles in AMIGAS - highlights the ubiquity of organosulfate species in the ambient aerosols of biogenically influenced urban environments.     

Diameter-dependent coloration of silver nanowires

Silver nanowires were synthesized with a green method and characterized with microscopic and diffractometric methods. The correlation between the colors of the nanowires deposited on a solid substrate and their diameters was explored. Silver nanowires that appear similar in color in the optical micrographs have very similar diameters as determined by atomic force microscopy. We have summarized the diameter-dependent coloration for these silver nanowires. An optical interference model was applied to explain such correlation. In addition, microreflectance spectra were obtained from individual nanowires and the observed spectra can be explained with the optical interference theory. This work provides a cheap, quick and simple screening method for studying the diameter distribution of silver nanowires, as well as the diameter variations of individual silver nanowires, without complicated sample preparation.     

Motivational pathways to alcohol use and abuse among Black and White adolescents.

Using data from a biracial community sample of adolescents, the present study examined trajectories of alcohol use and abuse over a 15-year period, from adolescence into young adulthood, as well as the extent to which these trajectories were differentially predicted by coping and enhancement motives for alcohol use among the 2 groups. Coping and enhancement motivations (M. L. Cooper, 1994) refer to the strategic use of alcohol to regulate negative and positive emotions, respectively. Results showed that Black and White youth follow distinct alcohol trajectories from adolescence into young adulthood and that these trajectories are differentially rooted in the regulation of negative and positive emotions. Among Black drinkers, coping motives assessed in adolescence more strongly forecast differences in alcohol involvement into their early 30s, whereas enhancement motives more strongly forecast differences among White drinkers. Results of the present study suggest that different models may be needed to account for drinking behavior among Blacks and Whites and that different approaches may prove maximally effective in reducing heavy or problem drinking among the 2 groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Race as a moderator in a model of sexual harassment: An empirical test.

L. F. Fitzgerald, C. L. Hulin. and F. Drasgow (1995) proposed that victim characteristics, such as race, might moderate the relationships between sexual harassment and its job, psychological, and health status outcomes. This study describes 2 theoretical positions, tokenism and double jeopardy, that could account for this possible moderation by race, as well as the alternative view that no moderating effects exist. The effects of race are empirically examined through simultaneous path analysis. Results indicate that whereas, mean levels of harassment differ across race, the phenomenon of sexual harassment unfolds similarly across races; race is not a moderator of the relationships between sexual harassment and the variables proposed as its antecedents and outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Safety climate and injuries: An examination of theoretical and empirical relationships.

Our purpose in this study was to meta-analytically address several theoretical and empirical issues regarding the relationships between safety climate and injuries. First, we distinguished between extant safety climate→injury and injury→safety climate relationships for both organizational and psychological safety climates. Second, we examined several potential moderators of these relationships. Meta-analyses revealed that injuries were more predictive of organizational safety climate than safety climate was predictive of injuries. Additionally, the injury→safety climate relationship was stronger for organizational climate than for psychological climate. Moderator analyses revealed that the degree of content contamination in safety climate measures inflated effects, whereas measurement deficiency attenuated effects. Additionally, moderator analyses showed that as the time period over which injuries were assessed lengthened, the safety climate→injury relationship was attenuated. Supplemental meta-analyses of specific safety climate dimensions also revealed that perceived management commitment to safety is the most robust predictor of occupational injuries. Contrary to expectations, the operationalization of injuries did not meaningfully moderate safety climate–injury relationships. Implications and recommendations for future research and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intra-amygdala infusion of the N-methyl-D-aspartate receptor antagonist AP5 blocks acquisition but not expression of fear-potentiated startle to an auditory conditioned stimulus.

The fear-potentiated startle paradigm, in which the amplitude of the startle reflex is enhanced in the presence of a stimulus previously paired with footshock, was used to measure aversive conditioning after intra-amygdala infusion of the competitive N-methyl-{d}-aspartate (NMDA) receptor antagonist {dl}-2-amino-5-phosphonopentanoic acid (AP5). Infusion of 2.5 μg/side AP5 immediately before 5 noise–footshock pairings on each of 2 consecutive days dose-dependently blocked acquisition or consolidation of auditory fear-potentiated startle, consistent with previous results obtained with a visual stimulus. Somatosensory or auditory transmission deficits do not appear to be induced by intra-amygdala AP5, because rats reacted normally to footshocks and showed reliable potentiated startle expression after pretesting AP5 infusion at a dose that blocked acquisition. Together with earlier reports, these data suggest that an NMDA-dependent process localized in or near the amygdala may be necessary for the acquisition of conditioned fear across different sensory modalities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of normal forgetting, psychopathology, and information-processing models of reported amnesia for recent sexual trauma.

This study assessed memories for sexual trauma in a nontreatment-seeking sample of recent rape victims and considered competing explanations for failed recall. Participants were 92 female rape victims assessed within 2 weeks of the rape; 62 were also assessed 3 months postassault. Memory deficits for parts of the rape were common 2 weeks postassault (37%) but improved over the 3 month window studied (16% still partially amnesic). Hypotheses evaluated competing models of explanation that may account for reported recall deficits. Results are most consistent with information processing models of traumatic memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)