Information Consistency and Perceptual Set: Overcoming the Mental Retardation “Schema”1

Two factors that were thought to promote or inhibit schema-based or stereotypic responding in impression formation were examined in two experiments. Subjects were asked to provide evaluations of artwork supposedly painted by either mentally retarded or nonretarded children. Based on previous research, it was assumed that subjects would expect relatively poor quality artwork from retarded children, which would he consistent with a negative schema that they maintain for this group. It was also predicted that this negative schema would result in cursory examinations and unfavorable evaluations of the retarded artists' artwork, but only when the evaluative conditions were conducive to schematic responding. Specifically, the schema effect was predicted to occur when the artwork was of poor quality and subjects were instructed to provide an overall evaluation of the painting rather than an assessment of its specific characteristics. No derogation was expected when these factors were not present. Results supported these hypotheses. Additional analyses indicated that subjects were conducting a cursory search of the target stimuli when conditions favored schema-based responding.     

New polytypes of long-period stacking ordered structures in a near-equilibrium Mg97Zn1Y2 alloy

By atomic-scale high-angle annular dark-field scanning transmission electron microscopy, the long-period stacking ordered (LPSO) structures in a near-equilibrium Mg₉₇Zn₁Y₂ (at.%) alloy have been characterised. In addition to 18R and 14H, new polytypes of LPSO structures are analysed and determined as 60R, 78R, 26H, 96R, 38H, 40H, 108H and 246R. All of these LPSO structures feature AB′C′A building blocks with two Mg layers and three Mg layers sandwiched between them. The Bravais lattices and space groups of new polytypes of LPSO structures were easily determined via the newly introduced method. A structural relationship between the LPSOs is proposed.     

AIDS and social exclusion: personality features or adaptive behaviors?

The purpose of this survey is to detect common personality features in people infected with AIDS who have a case history of drug addiction and who live in a situation of social exclusion. The sample comprised 105 male participants from the Autonomous Community of Andalusia, divided into 4 groups: (a) 30 men with AIDS, having an intravenous drug addiction case history and who live in a condition of social exclusion; (b) 30 men with IVDA case history, also living in a situation of social exclusion; (c) 15 men in a social exclusion condition; and (d) 30 men in a condition of social adaptation. The evaluation instruments were an author-designed semi-structured interview and the Multiaxial Clinical Inventory (MCMI-II; Millon, 1987). Although some differences were found, the results indicate that there is no specific personality profile in the "social exclusion" population. People in a condition of social exclusion (AIDS, drug addicts, and poor people) may obtain similar scores in the variables studied, but there is no clear specific personality profile in the excluded population, although there may be certain situations in which the segregated groups present similar behaviors. Furthermore, these behaviors do not always correspond to personality features but are adaptive responses to a harsh and complex reality.     

Resurgence is greater following a return to the training context than remaining in the extinction context

The present study examined whether resurgence of a previously reinforced target response upon removing alternative reinforcement would be greater when (1) returning to the original training context (ABA context changes) versus (2) remaining in the analogue treatment context in which the alternative response was differentially reinforced (ABB context changes). Experiment 1 arranged reinforcement of button pressing with points exchangeable for money in university students. Experiment 2 arranged reinforcement of lever pressing with food for rats. Experiment 3 arranged reinforcement of responses to a touchscreen with small bites of food with children diagnosed with ASD. Overall, resurgence of target responding tended to be greater when returning to the original training context (A) than when remaining in the analogue treatment context (B). These findings suggest context changes with differential reinforcement treatments could exacerbate the recurrence of problem behavior resulting from reductions in treatment integrity through failure to reinforce appropriate behavior.     

Effect of pressure on the mechanical and dynamical stability of NaAlSi

The effects of pressure on the mechanical and dynamical stability of NaAlSi have been fully investigated by first-principles calculations within the generalised gradient approximation (GGA). The obtained results show that the optimised lattice constants, atomic positions and elastic constants at ambient pressure are in good agreement with the available experimental and theoretical data. The lattice constants decrease monotonically with increasing pressure. The elastic constant C₁₁, C₁₂, C₁₃, C₃₃ and C₆₆ increase while C₄₄ decreases with increasing pressure. It is found that NaAlSi is mechanically unstable when the pressure is above 25.97?GPa. The phonon-dispersion curves along several high symmetry lines are obtained. The phonon frequencies at the Z point decrease with increasing pressure and completely soften to zero at 27.52?GPa, further confirming the structural instability of NaAlSi.     

Item response theory analyses of the Delis-Kaplan Executive Function System card sorting subtest

In the current study, we examined the dimensionality of the 16-item Card Sorting subtest of the Delis-Kaplan Executive Functioning System assessment in a sample of 264 native English-speaking children between the ages of 9 and 15 years. We also tested for measurement invariance for these items across age and gender groups using item response theory (IRT). Results of the exploratory factor analysis indicated that a two-factor model that distinguished between verbal and perceptual items provided the best fit to the data. Although the items demonstrated measurement invariance across age groups, measurement invariance was violated for gender groups, with two items demonstrating differential item functioning for males and females. Multigroup analysis using all 16 items indicated that the items were more effective for individuals whose IRT scale scores were relatively high. A single-group explanatory IRT model using 14 non-differential item functioning items showed that for perceptual ability, females scored higher than males and that scores increased with age for both males and females; for verbal ability, the observed increase in scores across age differed for males and females. The implications of these findings are discussed.     

Practicing Community Psychology Through Mixed Methods Participatory Research Designs

Community psychologists address social inequalities and problems by employing ecological principles, multiple methodologies, and participatory approaches to empower individuals, organizations, and communities to organize action and systems change. This article aims to contribute to mixed methods literature by presenting three models of mixed methods participatory research across a variety of geographic and sociocultural contexts. The models outline participatory processes and points of qualitative and quantitative data integration. Challenges related to the interplay between participatory approaches and mixed methods studies as well as implications on social science research are discussed.     

Leverpress Escape/Avoidance Training Increases Neurotrophin Levels in Rat Brain

In addition to their well-known role in neural development, the neurotrophins BDNF and NGF help mediate the plasticity that occurs in the brain to promote learning. Exposure to learning procedures often leads to increases in neurotrophins, while exposure to stress often results in decreases. It is unclear how the neurotrophins would respond to an aversive learning task. Therefore, BDNF and NGF content in the dorsal striatum, hippocampus, and basal forebrain was measured following discrete trial lever-press escape/avoidance conditioning. Conditioning significantly increased levels of both neurotrophins in hippocampus and basal forebrain, relative to home cage controls (HCC). Contrary to expectations, the dorsal striatum did not show any significant changes. However, significant correlations were observed between dorsal striatal neurotrophins and aspects of avoidance performance. This may indicate that the dorsal striatum is involved in the performance aspects of the task. Results are discussed in terms of the role of neurotrophins in the acquisition of new information, and the neural structures involved in different types of memory.     

Behavioral profile of L‐655,708, a selective ligand for the benzodiazepine site of GABA‐A receptors which contain the α5 subunit,in social encounters between male mice

GABA‐A receptor is a transmembrane hetero‐oligomeric protein which consists of five subunits, the combination of which confers unique pharmacological properties to the receptor. It is well‐known that the GABAergic system is involved in the modulation of aggression. However, the role of α5/GABA‐A receptors has not been explored. In this study, we examined the effect of L‐655,708 (0.625‐5 mg/kg), a selective ligand for the benzodiazepine site of GABA‐A receptors which contain the α5 subunit, on agonistic behavior elicited by isolation in male mice. Individually housed mice were exposed to an anosmic “standard opponent” 30 min after drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. L‐655,708 (5 mg/kg) exhibited an ethopharmacological profile characterized by a marked reduction of the time spent in offensive behavior (threat and attack) without affecting immobility, accompanied by a significant increase of avoidance/flee and nonsocial exploration behaviors, suggesting that the antiaggressive effect of the drug is unselective. Overall, this behavioral profile might indicate the existence of an anxiogenic‐like activity of L‐655,708 in mice. Aggr. Behav. 30:319–325, 2004. © 2004 Wiley‐Liss, Inc.