Chronic cadmium exposure alters cocaine self-administration in adult male rats.

Adult male rats (Rattus norvegicus) were exposed to a water supply in the home cage containing 100 ppm cadmium chloride and sodium saccharin (.65% wt/vol; cadmium group) or water containing only the saccharin amendment (group control). On Day 65 of exposure, animals from each group received jugular catheter implants and were subsequently trained over the course of 15 daily 2-hr sessions to self-administer a .25 mg/kg/infusion of cocaine HCl under a fixed ratio 1 schedule. Immediately following acquisition training, the full dose-effect function was determined for all animals by using cocaine doses of .03, .06, .125, .25, .50, and 1.0 mg/kg. Cadmium-exposed animals executed more active (cocaine) lever responses during acquisition training but were not different from controls in depressing a pharmacologically inactive lever. For dose-effect testing, cadmium exposed animals exhibited greater self-administration than controls at the higher doses of cocaine, and there was evidence that the cocaine dose that produced maximum responding was higher in cadmium-exposed than control animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Masking by light in Limulus receptors.

Measured electrophysiological analogs of visual masking by light in single retinula (photoreceptor) cells of the lateral eye of Limulus. The intensity required for a 30-msec test flash to produce a criterion response increment in the presence of a 400-msec masking flash was determined over a range of stimulus onset asynchronies. The variation of the criterion intensity with stimulus onset asynchrony yielded a masking function quite similar to that obtained in human psychophysics, which suggests that this kind of response integration occurs in the most peripheral cell and that network interactions are not needed to account for masking by light. The implication that photoreceptor dynamics alone determine masking was examined: The criterion test flash intensity increased with receptor potential increases, but the relation could best be described by a bilinear function. It is suggested that the upper limb of the bilinear function may represent receptor saturation. Results are consistent with the notion that masking by light is a special case of the increment threshold and that receptor dynamics adequately account for dynamic factors in masking by light at this level of the visual system. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ways to deter law violators: Effects of levels of threat and vicarious punishment on cheating.

Determined whether threat of severe, moderate, or mild sanctions and/or vicarious punishment would deter law violators from cheating, and whether law violators could be deterred as easily as law abiders. 123 undergraduates completed a sexual and a criminal behavior checklist (to differentiate law violators from abiders) and the Test Anxiety Scale. On the sexual and criminal behavior checklists, Ss indicated which specific offenses or behaviors they had committed, how many times they had committed them, and whether they had been apprehended. Ss then completed the School and College Ability Test under 7 conditions. Results show that (a) law violators cheated more than law abiders, (b) Ss cheated less if they witnessed a model apprehended for cheating, (c) law violators who were just severely threatened were the most dishonest, (d) law violators who saw a model apprehended and treated leniently cheated significantly more than law violators who saw a peer model caught and punished, and (e) high test-anxious Ss cheated more than low test-anxious Ss. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transport in oriented bottles made from polyester resin

Oxygen permeation has been measured in flat sheet as a function of degree of orientation, and oxygen and water transport have been measured in oriented polyester bottles. O₂ permeability in flat sheets decreases gradually with orientation on either side of an abrupt decrease by about a factor of 2 after moderate orientation. The bottles tested were all more highly oriented than that critical decree; no significant effect of orientation on water or O₂ transport in bottles could be found. Only container intrinsic viscosity (IV) (which is determined by molecular weight, and is therefore a convenient measure of polymer degradation) was significantly related to the transport properties of the bottles. It was found that O₂ transport is increased with increasing IV while H₂O transport decreased. The explanation for these seemingly contradictory data can be found in the chemistry of degradation of the polyester.     

Use of MMPI subtypes in predicting completion of a residential alcoholism treatment program.

To obtain data on patient characteristics relevant to treatment outcome, the Minnesota Multiphasic Personality Inventory (MMPI) was administered to 86 men 3–5 days following their admission to a 30-day residential alcoholism treatment program. Cluster analyses yielded three subtypes whose mean MMPI code types were as follows: Type I comprised a 4-2-8 code type, with marked additional pathology; Type II comprised a 4-9/9-4 code type; and Type III comprised a 2-4/4-2 code type. The subtypes differed significantly in their rates of treatment completion, with Type II yielding a greater proportion of program dropouts. To investigate the effect of time of MMPI administration on subtype results, 68 subjects who remained in treatment were readministered the MMPI 14–26 days following admission. A comparison of Time 1 and Time 2 typologies highlights the importance of test administration time and provides some explanation for previous discrepant findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Two-stage screening for stressful life events and chronic difficulties.

93 adult women completed a depression scale and a checklist on stressful life events and were interviewed 1 wk later in their homes. With the interview as the criterion, the checklist assessed stressful life events with a sensitivity of .89 and a specificity of .57. The corresponding figures for the assessment of chronic difficulties were .86 and .55. For the total sample, sensitivity and specificity were .88 and .67 for life events and .75 and .75 for chronic difficulties. Interview and checklist techniques were highly correlated when a severe life event had not occurred (negative predictive value), but events marked on the checklist had a 20–27% correspondence to events related in the interview (positive predictive value). (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Charging of Polar Versus Nonpolar Liquids During Brief Exposure to Ionic Currents

Experimental results are reported which show the amount of corona charging of polar and nonpolar liquid droplets during brief exposure to ionic currents. They show that the nonpolar materials tested acquired from 10 to 36 percent less charge than equivalent water droplets and that the polar materials acquired from 1 to 15 percent more charge than the water. These differences are not predicted by the Pauthenier theory. The reason for the differences is believed to be due to the relaxation time of the materials and the effect it has on the rate at which the ionic particles may distribute themselves over the surface of the droplet. In particular, the nonpolar materials being highly resistive have long relaxation times and thus acquire fewer charges than the polar materials.     

Remote sensing data of SP Mountain and SP Lava flow in North-Central Arizona

Multifrequency airborne radar image data of SP Mountain [Official name of feature (U.S. Geological Survey, 1970)] and SP flow (and vicinity) in north-central Arizona were obtained in diverse viewing directions and direct and cross-polarization, then compared with surface and aerial photography, LANDSAT multispectral scanner data, airborne thermal infrared imagery, surface geology, and surface roughness statistics. The extremely blocky, basaltic andesite of SP flow is significantly brighter on direct-polarization $\text{K-}\text{band}$ (0.9-cm wavelength) images than on cross-polarized images taken simultaneously. Conversely, for the longer wavelength (25 cm) $\text{L-}\text{band}$ radar images, the cross-polarization image returns from SP flow are brighter than the direct-polarized image. This effect is explained by multiple scattering and the strong wavelength dependence of polarization effects caused by the rectilinear basaltic andesite scatters. Two distinct types of surface relief on SP flow, one extremely blocky, the other subdued, are found to be clearly discriminated on the visible and thermal wavelength images but are separable only on the longer wavelength $\text{L-}\text{band}$ radar image data. The inability of the $\text{K-}\text{and}\text{X- (3-}\text{cm wavelength}\text{)}$ band radars to portray the differences in roughness between the two SP flow surface units is attributed to the radar frequency dependence of the surface-relief scale, which, described as the Rayleigh criterion, represents the transition between quasispecular and primarily diffuse backscatter.     

Helplessness and depression in end-stage renal disease.

45 dialysis and 25 posttransplant patients (mean age 40.6 yrs) participated in interviews and were administered a battery of tests, including the Beck Depression Inventory, Health Locus of Control Scale, Rotter's Internal–External Locus of Control Scale, and Self-Esteem Inventory. Separate ratings made by hospital staff and family were also obtained. Analyses revealed that perceived control over nontreatment life dimensions was importantly related to depression, although data failed to provide strong support for a reformulated helplessness theory. (58 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Numerical comparison of kalman filter algorithms: Orbit determination case study

Numerical characteristics of various Kalman filter algorithms are illustrated with a realistic orbit determination study. The case study of this paper highlights the numerical deficiencies of the conventional and stabilized Kalman algorithms. Computational errors associated with these algorithms are found to be so large as to obscure important mismodeling effects and thus cause misleading estimates of filter accuracy. The positive result of this study is that the U-D covariance factorization algorithm has excellent numerical properties and is computationally efficient, having CPU costs that differ negligibly from the conventional Kalman costs. Accuracies of the U-D filter using single precision arithmetic consistently match the double precision reference results. Numerical stability of the U-D filter is further demonstrated by its insensitivity to variations in the a priori statistics.