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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.
Interactions between area and numerosity   总被引:2,自引:0,他引:2  
Summary The concept of filled area, i.e. the impressionistic ensemble of parts of a stimulus field occupied by dots, is used to account for various kinds of numerosity illusions due to perceptual interaction between a number of dots and their spatial arrangement. A measure of filled area is derived from a model for the perceptual clustering of dots on the basis of relative proximity. It is shown that the quantified concept of filled area successfully predicts illusion data from earlier studies. Subsequently, a two-alternatives forced-choice numerosity experiment is reported, the data of which gave further evidence of the predictive power of the filled-area hypothesis. Our approach is discussed with respect to spatial features of dot stimuli that might be in rivalry with the filled-area factor in numerosity-estimation tasks.  相似文献   
4.
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   
5.
In studies related to human movement, linked segment models (LSM's) are often used to quantify forces and torques, generated in body joints. Some LSM's represent only a few body segments. Others, for instance used in studies on the control of whole body movements, include all body segments. As a consequence of the complexity of 3-dimensional (3-D) analyses, most LSM's are restricted to one plane of motion. However, in asymmetric movements this may result in a loss of relevant information. The aim of the current study was to develop and validate a 3-D LSM including all body segments. Braces with markers, attached to all body segments, were used to record the body movements. The validation of the model was accomplished by comparing the measured with the estimated ground reaction force and by comparing the torques at the lumbo-sacral joint that resulted from a bottom-up and a top-down mechanical analysis. For both comparisons, reasonable to good agreement was found. Sources of error that could not be analysed this way, were subjected to an additional sensitivity analysis. It was concluded that the internal validity of the current model is quite satisfactory.  相似文献   
6.
OBJECTIVE: To examine the influence of parental solicitousness on self-reported somatic complaints in school-age children. DESIGN AND MAIN OUTCOME MEASURES: Participants were 564 children (mean age 10 years) and their parents. Children completed self-report measures of somatic complaints, parental solicitousness, depressiveness, fear, and sense of coherence. Somatic complaints were assessed again 6 months later. Parents also completed a questionnaire about solicitousness. RESULTS: Parental solicitousness as reported by children or parents was unrelated to the frequency of self-reported somatic complaints. Symptoms of depression, fear, and lower sense of coherence were associated with more somatic complaints, but did not interact with parental solicitousness. CONCLUSION: Parental solicitousness seems unrelated to more frequent somatic complaints in schoolchildren.  相似文献   
7.
Issues studied by Peabody (1985) in a study of national stereotypes were investigated again in a secondary analysis of public opinion data from the general public in a number of European countries. A convergence in stereotyping among perceiver groups was shown. In contrast with Peabody's results, strong ingroup favouritism was found.  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.
In the masked priming paradigm, motor responses to targets are influenced by previously presented subliminal primes, and are guided by facilitatory and inhibitory mechanisms that depend on prime-target compatibility/duration. In this study, we evaluate subliminal-driven priming in right- and left-handers during unimanual as well as bimanual tasks. The data from the unimanual tasks confirmed that prime-target compatibility affects performance as a function of prime-target duration. In a bimanual setting, the preferred hand benefitted from facilitation in both handedness groups whereas the non-preferred hand showed a positive priming effect only in left-handers. This denotes that left-handers are more susceptible to response activation of either hand. In addition, inhibitory priming had a stronger effect on the non-preferred than preferred hand, independent of handedness group. Overall, the findings suggest that subliminal-driven mechanisms that assist adaptive motor behavior are sensitive not only to extrinsic (task-related) factors such as prime-target compatibility but also to intrinsic (performer-related) factors such as hand dominance. The data further provide support for handedness-specific effects in motor functions and underline a significant role of hand dominance in the control of bimanual actions.  相似文献   
10.
The present study investigated how multisensory integration in peripersonal space is modulated by limb posture (i.e. whether the limbs are crossed or uncrossed) and limb congruency (i.e. whether the observed body part matches the actual position of one’s limb). This was done separately for the upper limbs (Experiment 1) and the lower limbs (Experiment 2). The crossmodal congruency task was used to measure peripersonal space integration for the hands and the feet. It was found that the peripersonal space representation for the hands but not for the feet is dynamically updated based on both limb posture and limb congruency. Together these findings show how dynamic cues from vision, proprioception, and touch are integrated in peripersonal limb space and highlight fundamental differences in the way in which peripersonal space is represented for the upper and lower extremity.  相似文献   
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