Internet use in the contemporary media environment

Although a significant amount of research has focused on traditional media choice and use, and even on some ‘new’ media, these studies have either neglected the Internet and World Wide Web or were conducted prior to their recent popularity. This study offers a novel exploration of individuals' use of three Internet functions (information retrieval, information giving, and conversation capabilities) in the context of the use of other communication media. Data from 684 individuals demonstrate that the Internet is a multidimensional technology used in a manner similar to other, more traditional media. Specifically, conversation features of the Internet align with mediated interpersonal technologies (the telephone and electronic mail), whereas the Internet's information‐retrieval and information‐giving features are used in ways similar to mass media channels (newspapers, television, and books and magazines). In addition, needs fulfilled by these channels cluster in ways consistent with past research, regardless of the technologies employed to meet them.     

In Vivo Hippocampal Acetylcholine Release During Exposure to Acute Stress

Hippocampal extracellular acetylcholine (ACh) and choline levels were evaluated using in vivo microdialysis in male Fischer 344 rats before, during, and following an 80-min exposure to two different stress conditions. Measurements were taken in rats restrained and immersed in a water bath containing either 37 degreesC (normothermic-restraint) or 20 degreesC (cold-restraint) water. Results were compared to normothermic-freely-moving rats. Cold-restrained rats displayed decreased ACh levels during cold exposure relative to both normothermic-restrained and normothermic-freely-moving rats. By the end of the cold exposure period and following removal from cold, ACh levels had returned to near-baseline values. Normothermic-restrained rats had levels similar to those of normothermic-freely-moving rats, except for a marked increase in ACh following removal from restraint. Cold-restrained rats displayed a gradual elevation in choline levels during cold stress, followed by a gradual decline after stress termination, whereas both normothermic-restrained and normothermic-freely-moving rats displayed gradual decreases during the microdialysis session. These findings demonstrate that central cholinergic neurotransmission can be altered by the application of, and removal from, acute stressors. In addition, the results suggest a possible relationship between the magnitudes of both the stressor and its cholinergic consequences.     

Biculturalism,Locus of Control,and Leader Behavior in Ethnically Mixed Small Groups1

The study examined the interactive effects of degree of biculturalism and locus of control on leader behavior in supportive and nonsupportive ethnically mixed small groups. Subjects were 36 male Chicano college students who participated in a small group discussion composed of four members: a naive subject who invariably served as group leader, and three confederates representing distinct ethnic groups (Anglo, Black, and Chicano). Behavioral observations revealed several interesting interactions involving group support. High biculturals, in comparison to low biculturals, adopted a more active leader role in nonsupportive than in supportive groups, asking for more opinions and evaluations, and making more clarification statements. Furthermore, while low bicultural externals and high bicultural internals tended to be more interpersonally assertive and to make more clarification statements under supportive conditions, it was low bicultural internals and high bicultural externals who exhibited the most active leader roles in nonsupportive groups. Additional findings revealed that statements made by the Anglo confederate were clarified more often in the supportive condition, while statements made by either the Black or the Chicano confederate were clarified more often in the nonsupportive condition. The results are discussed in relation to previous literature and the need to develop a more responsive social psychology of interethnic dynamics.     

Economic optimization by compromise programming: The joint production model

In a basic microeconomic model (joint production and consumer's utility curves) three key optima appear: the best technological mix, the maximum profit point and the consumer's utility optimum. Compromise analysis can help to clarify their connections. This paper and other recent research attempt to specify the conditions which guarantee that these three optima coincide. Thus compromise programming becomes a valuable surrogate of economic optimization.     

Stress within a bicultural context for adolescents of Mexican descent

Folkman and Lazarus's theory of stress and coping was used to develop a measure assessing the perceived stress within a bicultural context. Middle school students of Mexican descent (N = 881) reported their perceived stress from intergenerational acculturation gaps, within-group discrimination, out-group discrimination, and monolingual stress. Although immigrant youths reported more total number of stressors, U.S.-born youths reported more stress from needing better Spanish and impact of parents' culture. Immigrant youths reported more stress from needing better English in school. Higher stress was associated with more depressive symptoms for both U.S.-born and immigrant youths. Although this study has identified some elements of stress, it has not identified positive coping mechanisms of the bicultural context for Latino youths.     

Values and antisocial behavior among Spanish adolescents

A number of studies have indicated that delinquent adolescents have characteristic value systems. However, most of these studies have adopted a "known-groups" design--that is, they have compared institutionalized delinquents and non-institutionalized adolescents, assuming those adolescents to be non-delinquent. Designs of this type do not distinguish effectively between the statistical effects of delinquency and of institutionalization. In this study, the authors investigated relationships between values and self-reported antisocial behavior in three adolescent groups: 435 school-attending boys, 529 school-attending girls, and 95 delinquent boys in juvenile rehabilitation centers or prisons. The results indicate that antisocial behavior is associated with hedonistic values and a lack of interest in conventional values and social values. These relationships cannot be explained by the institutionalization effects.     

Psychopathic personality as a distinctive indicator of severity and persistence for child and youth conduct problems

Conduct problems are among the most discussed behavioral problems during childhood and adolescence. Given their heterogeneity, in recent years, researchers on this topic have called for delineation of early-onset conduct problems on the basis of affective, interpersonal and behavioral traits that resemble adult psychopathy. The present study aims to analyze, from both a cross-sectional and longitudinal perspective, whether early psychopathic traits allow identification of a group of individuals defined by severe and persistent behavioral problems. To achieve this goal, data from a sample of 192 children (aged 6 to 11) were analyzed; from this sample, 133 children were followed-up in a new data collection that took place three years later. From the data obtained with the mCPS and CBCL (parents), and APSD and TRF (teachers), we observed that children who showed early psychopathic traits, also showed greater frequency, severity and persistence of conduct problems. These results suggest the need to take into account the role of psychopathic traits (particularly, affective and interpersonal) as risk factors to delimit the most serious and persistent patterns of externalizing behavior.     

Exposure to severe urban air pollution influences cognitive outcomes, brain volume and systemic inflammation in clinically healthy children

Exposure to severe air pollution produces neuroinflammation and structural brain alterations in children. We tested whether patterns of brain growth, cognitive deficits and white matter hyperintensities (WMH) are associated with exposures to severe air pollution. Baseline and 1 year follow-up measurements of global and regional brain MRI volumes, cognitive abilities (Wechsler Intelligence Scale for Children-Revised, WISC-R), and serum inflammatory mediators were collected in 20 Mexico City (MC) children (10 with white matter hyperintensities, WMH⁺, and 10 without, WMH⁻) and 10 matched controls (CTL) from a low polluted city. There were significant differences in white matter volumes between CTL and MC children - both WMH⁺ and WMH⁻ - in right parietal and bilateral temporal areas. Both WMH⁻ and WMH⁺ MC children showed progressive deficits, compared to CTL children, on the WISC-R Vocabulary and Digit Span subtests. The cognitive deficits in highly exposed children match the localization of the volumetric differences detected over the 1 year follow-up, since the deficits observed are consistent with impairment of parietal and temporal lobe functions. Regardless of the presence of prefrontal WMH, Mexico City children performed more poorly across a variety of cognitive tests, compared to CTL children, thus WMH⁺ is likely only partially identifying underlying white matter pathology. Together these findings reveal that exposure to air pollution may perturb the trajectory of cerebral development and result in cognitive deficits during childhood.     

The Role of Neighborhood in the Development of Aggression in Urban African American Youth: A Multilevel Analysis

The purpose of this study was to examine the role of neighborhood disadvantage and perceptions of neighborhood on the development of aggressive behavior among a sample of urban low‐income African American middle school aged youth (mean age = 11.65 years). Results of hierarchical linear modeling indicated that youth experienced significant changes in rates of aggression across the three middle school years, and that on average, negative youth perceptions of neighborhood predicted increases in aggression. Both parent and youth perceptions of neighborhood disadvantage trended toward significance as a moderator between objective neighborhood characteristics and aggression. These results are in accordance with past research, which suggests that personal evaluations of the disadvantage of a neighborhood influence child development and behavior. Future studies should examine the role that perceptions play in youth development, as well as in interventions geared towards thwarting youth aggression.