A study of the solid solutions PbyMo6X8−xX′x and Mo6X8−xX′x (X,X′ = S,Se, Te) and their superconducting properties

The solid solutions Pb_yMo₆X_8?xX′_x and Mo₆X_8?xX′_x (X, X′ = S, Se, Te) are studied and it is shown that there are correlations between T_c and certain structural parameters.     

Cover Image

The cover image is based on the Review Review: materials and modelling for organic photovoltaic devices by Olivier Doat et al., https://doi.org/10.1002/pi.6280 .

     

Using behavior to elucidate receptor mechanisms: A review of the discriminative stimulus effects of benzodiazepines.

Drug discrimination procedures have been used to study receptor mechanisms of benzodiazepine (BZ) agonists with the goal of developing new therapeutic agents that retain positive effects of conventional BZ ligands yet have reduced side effects. The present review provides a synthesis of existing literature on discriminative stimulus effects of BZ agonists in order to elucidate their underlying receptor mechanisms, specifically in terms of intrinsic efficacy and receptor selectivity. The available evidence suggests that receptor selectivity is a critical determinant of the discriminative stimulus effects of BZ agonists. In particular, BZ-1 receptors appear to play a fundamental role, whereas the role of BZ-2 receptors remains elusive. In addition, data from many drug discrimination studies suggest that the conventional BZ agonist chlordiazepoxide may have reduced intrinsic efficacy compared with other BZ agonists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A diffusion model account of masking in two-choice letter identification.

The diffusion model developed by R. Ratcliff (1978, 1981, 1985, 1988) for 2-choice decisions was applied to data from 2 letter identification experiments. In the experiments, stimulus letters were displayed and then masked, and the stimulus onset asynchrony between letter and mask was manipulated to vary accuracy from near chance to near ceiling. A standard reaction time procedure was used in one experiment and a deadline procedure in the other. Two hypotheses about the effect of masking on the information provided to the decision process were contrasted: (1) The output of perception to the decision process varies with time, so that the information used by the decision process rises and falls, reflecting the stimulus onset and mask onset. (2) The output of perception to the decision is constant over time, reflecting information integrated over the time between the stimulus and mask onsets. The data were well fit by the diffusion model only with the assumption of constant information over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

There are no Fullerenes in the K-T Boundary Layer

Careful re-examination of the Cretacous-Tertiary boundary layer material that was reported earlier to contain C₆₀, confirms that there is a peak in the HPLC of the extract having a retention time similar to that of C₆₀ (the basis of the earlier claim). However, mass spectrometric analysis shows this to be merely a mixture of hydrocarbons. No traces of either C₆₀ or C₇₀ are present under conditions capable of detecting as little as 50 pg (0.001 part per billion in the original material), this sensitivity being four times greater than that given in the earlier report. These findings are entirely consistent with the known high oxidative instability of fullerenes.     

On the problem of detecting effects of lifestyle on cognitive change in adulthood: Reply to Pushkar et al. (1999).

The authors respond to issues raised about data from the Victoria Longitudinal Study and further explain concerns regarding evidence for the engagement hypothesis. Discussion focuses on the use of social stratification variables such as occupational prestige and educational attainment as measures of an engaged lifestyle. It is argued that (a) tests of the hypothesis should focus on the relationship of behaviors and activities thought to be proximal beneficial influences on adult cognitive development; (b) persuasive evidence for engagement effects from existing data require demonstration of effects of intellectual activities that are statistically independent of associations of social status with intellectual and cognitive development; and (c) currently available longitudinal data do not provide definitive evidence regarding the benefits of an engaged lifestyle on cognitive change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physiologic reactivity to startling tones in women with posttraumatic stress disorder.

Autonomic and eyeblink reactivity to startling tones were investigated in women with histories of childhood sexual abuse (CSA). Twenty-one women with current posttraumatic stress disorder (PTSD), 23 with lifetime but not current PTSD, and 13 women who never had PTSD listened to 15 95-dB, 500-ms, 1000-Hz tones with a 0-ms rise time while heart rate (HR), skin conductance (SC), and orbicularis oculi electromyogram (EMG) responses were measured. Participants in the current and lifetime PTSD groups produced larger HR responses across tones and showed slower absolute habituation of SC response magnitude compared with the never PTSD group. EMG response magnitudes did not differ among groups. Women with CSA-related PTSD showed increased autonomic reactivity and slower habituation to high-intensity tones similar to that observed in primarily male, combat PTSD samples. This suggests that heightened autonomic responsivity to startling stimuli in PTSD is not gender or event specific. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PARTICLE CHARACTERIZATION FOR OIL SAND PROCESSING 2: PARTICLE SIZE MEASUREMENTS BY LASER DIFFRACTION

Particle size measurements of oil sands solids by laser diffraction are reviewed together with the process used at Syncrude to replace old laser diffraction instruments with current ones. The new instrument has a much broader measurement range and by accounting for fine particles (smaller than 1 μm) it addresses a major limitation of earlier instruments. Results from both laser diffraction instruments are compared so that new results can be related to our historic database. Results from the new instrument are also compared with those from a disc centrifuge and the hydrometer method. It is concluded that the new instrument can be used for samples that were previously analyzed by these other techniques and so is the preferred particle size method for almost all oil sand processing solids.