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1.
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.  相似文献   
2.
Public goods theories highlight an incentive system that rewards ‘free riding’ on the contributions of early contributors toward collective actions. However, because such theories focus on creation of the good, they may underestimate returns that accrue to early contributors subsequent to the good's realization. The concept of formative investment is introduced here to describe the extent to which organizations help to create public goods such as interorganizational linkages like participatory federations. Data from the CEOs of 48 organizations involved in a participatory federation were used to assess how an organization's level of formative investment is related to later patterns of dependency and interaction among federation members. Findings suggest that from a long‐term perspective, and for goods that involve communication and interaction, the incentive structure may not be so favorable for free riders. To the extent that organizations with high formative investment have the capability to envision the future and communicate that vision to potential federation partners, they may be able to both reduce free riding and secure for themselves advantageous positions in the subsequent network of relations.  相似文献   
3.
Molecular sequence data, made available in the last 15 years or so, have led to the classification of living cells into three phylogenetic domains: Bacteria, Archaea, and Eucarya. All the organisms that have been tested belonging to either domain were capable of mounting a stress response with essentially the same characteristics, regardless of the stressor. The protagonists in the cell's stress response are the stress genes and their protein products. Some of the latter are molecular chaperones. Under physiological conditions, these chaperones aid other cellular proteins to fold properly and achieve a native -functional- configuration, and to translocate from the place of synthesis to the cell's locale in which they will operate. In a stressed cell, the stress proteins that are chaperones protect other molecules from denaturation and help those partially damaged to regain a functional configuration. Thus, cell death is avoided and recovery is enhanced. The study of stress genes and proteins has progressed considerably in organisms belonging to the domains Bacteria and Eucarya. Less is known about the archaeal stress genes. Here, research with an organism from the Archaea is discussed, focusing on the stress genes of the hsp70 (dnaK) locus. Future perspectives for basic and applied research within the health sciences and biotechnology industries are presented.  相似文献   
4.
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.  相似文献   
5.
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.  相似文献   
6.
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.  相似文献   
7.
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.  相似文献   
8.
Although children born preterm or low birth weight (PT LBW) are more likely to exhibit behavior problems compared to children born at term, developmental and family processes associated with these problems are unclear. We examined trajectories of maternal depressive symptoms in relation to toddler compliance and behavior problems in families with PT LBW infants. A total of 177 infants (93 boys, 84 girls) and their mothers enrolled in the study during the infant's NICU stay. Data were collected at five time points across 2 years. Assessments of maternal depressive symptoms were conducted at all time points, and toddler compliance and opposition to maternal requests and behavior problems were assessed at 2 years. Toddlers born earlier with more health problems to mothers whose depressive symptoms increased over time exhibited the most opposition to maternal requests during a cleanup task at 24 months, consistent with multiple risk models. Mothers with elevated depression symptoms reported more behavior problems in their toddlers. The study has implications for family‐based early intervention programs seeking to identify PT LBW infants at highest risk for problem behaviors.  相似文献   
9.
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.  相似文献   
10.
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.  相似文献   
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