A simulation study of the degrees of freedom of movement in reaching and grasping

The question of independently controlled components in the act of reaching and grasping has attracted interest experimentally and theoretically. Data from 35 studies were recently found consistent with simulated kinematic finger and thumb trajectories optimised for minimum jerk. The present study closely reproduces those trajectories using a discrete-time model based on minimum acceleration. That model was further used to generate two-dimensional trajectories for finger and thumb to reach and grasp an elliptical object with varying position and/or orientation. Orthogonalisation of these four trajectories revealed one degree of freedom when direction of reach was constant and two degrees of freedom when direction of reach varied, irrespective of object distance and orientation. These simulations indicate that reach and grasp movements contain redundancy that is removable by formation of task-dependent synergies. As skilled movement can be planned and executed in a low dimension workspace, control of these independent components lessens central workload.     

社会因素对剖宫产率的影响

近二三十年来,剖宫产率在世界范围内不断升高。究其原因,除了医学因素外,社会因素起着重要作用,从社会经济发展,社会科学文化水平、社会习俗观念、法律、医疗道德、国家计划生育政策、医学教育等多个角度分析了社会因素对剖宫产率的影响,并就如何发挥社会因素的积极作用,消除和避免其消极作用,使剖部率维持在合理的范围内进行了讨论。     

Memory for action events: findings in neurological patients

Encoding action phrases by enacting leads normally to better memory performance than verbal encoding. In order to gain additional insight into the representational basis of the enactment effect, neurological patients are contrasted with healthy participants. Persons suffering from Parkinson's disease, which primarily impairs the motor system, and patients suffering from Frontal Lobe Syndrome, which primarily affects action-related planning processes, were involved. We investigated whether the enactment effect would be differentially affected by these disorders. In addition, the characteristics of information processing after encoding by enacting was analyzed by varying memory material (unrelated versus clusterable actions) and by adding an encoding condition that included obligatory action planning (director condition). The findings indicate that the impact of motor information for the enactment effect is not dominant compared to the role of action-related cognitive and motivational processes, in particular planning processes. The findings of the two experiments are explained within traditional conceptual memory theories.     

Getting the Big Picture in Community Science: Methods That Capture Context

Community science has a rich tradition of using theories and research designs that are consistent with its core value of contextualism. However, a survey of empirical articles published in the American Journal of Community Psychology shows that community scientists utilize a narrow range of statistical tools that are not well suited to assess contextual data. Multilevel modeling, geographic information systems (GIS), social network analysis, and cluster analysis are recommended as useful tools to address contextual questions in community science. An argument for increased methodological consilience is presented, where community scientists are encouraged to adopt statistical methodology that is capable of modeling a greater proportion of the data than is typical with traditional methods.     

Using Methods That Matter: The Impact of Reflection,Dialogue, and Voice

In recent years, the field of community psychology has given considerable attention to how research and evaluation methods should be designed to support our goals of empowerment and social justice. Yet, as a field, we have given much less attention to whether the use of our methods actually achieves or supports our empowerment agenda. With the primary purpose of beginning to establish the norm of reporting on the impacts of our methods, this paper reports on the findings from interviews of 16 youth and adults who had participated in one participatory evaluation method (Photovoice). Two specific questions were examined: (1) What is the impact of participating in a Photovoice effort; and (2) How does the method of Photovoice foster these impacts? Overall, participants noted that they were significantly affected by their experiences as photographers and through their dialogue with neighbors during Photovoice group sessions. Impacts ranged from an increased sense of control over their own lives to the emergence of the kinds of awareness, relationships, and efficacy supportive of participants becoming community change agents. According to participants, Photovoice fostered these changes by (a) empowering them as experts on their lives and community, (b) fostering deep reflection, and (c) creating a context safe for exploring diverse perspectives. The implications of these findings for the science and practice of community psychology are discussed.     

Learning from Communities: Overcoming Difficulties in Dissemination of Prevention and Promotion Efforts

The model of prevention science advocated by the Institute of Medicine (P. J. Mrazek & R. J. Haggerty, 1994) has not lead to widespread adoption of prevention and promotion programs for four reasons. The model of dissemination of programs to communities fails to consider community and organizational capacity to implement programs, ignores the need for congruence in values between programs and host sites, displays a pro-innovation bias that undervalues indigenous practices, and assumes a simplistic model of how community organizations adopt innovations. To address these faults, researchers should locate, study, and help disseminate successful indigenous programs that fit community capacity and values. In addition, they should build on theoretical models of how locally developed programs work to make existing programs and polices more effective.     

Community Science: Creating an Alternative Place to Stand?

This article comments on two emerging views of community psychologys approaches to the use of research for responding to social problems in contemporary community contexts – (a) the formation of a new field of community science, or (b) the updating of community psychology research traditions. If community science is to become established as a field related to community psychology, its proponents will need to agree upon conventions of epistemology, foci of interest, methods, and standards by which its work can be judged so that it can be distinguished from other human sciences. These articles provide early sketches for what community science might be. However, as noted in this commentary, we need to heed signs of concern about community psychologys continued relevance in public discourse regarding the analysis of and responses to social problems. While this special issue offers some promising responses to the concern of what the field can contribute, the field would be well served if we broaden our dialogue about a renewal of community psychologys commitment to social justice and the need for its perspectives in the practice of research that seeks to address community-based issues in the early 21st century.     

Quality and Individualization in Wraparound Team Planning

In children’s mental health, collaborative, team-based individualized service planning is most commonly known as wraparound, and has become one of the primary strategies for improving services and outcomes for children with the highest levels of need. We report on analyses of data gathered at 72 wraparound team meetings from communities around the United States. We describe the composition of the teams and the quality of the planning process they engaged in, and explore the extent to which these factors were associated with team member satisfaction and the individualization of plans. Teams in our study were numerically dominated by professionals. Parents attended a large majority of meetings, participation by youth and family advocates was frequent, participation by other family members infrequent, and participation by other members of the family’s informal or natural support networks rare. Observed teams varied considerably in the quality of their planning process and the degree of individualization of plans. Higher-quality planning was significantly associated with increased individualization of plans and with team member satisfaction with meeting productivity.     

Epidemiological Measurement of Children's and Adolescents' Exposure to Community Violence: Working with the Current State of the Science

A number of measures have been used in epidemiological studies of children's exposure to community violence, yet the quality of these instruments is not uniformly good. This paper undertakes a systematic review of the most commonly used (or most promising) self-report or interview-administered instruments, with regard to their conceptual bases and psychometric properties. Based on the review, recommendations are made for working with the current state of the science in order to move the field forward. A key recommendation is for sounder conceptualization of work in the field and greater transparency in the reporting of research, in order to facilitate the comparability of studies.     

Beyond the Frontstage: Trust, Access, and the Relational Context in Research with Refugee Communities

This paper examines the role of trust and the concept of access as they affect the relational context in which community research, and research with refugee communities in particular, is conducted. Sociologist Irving Goffman's metaphor of frontstage and backstage behavior is used to illustrate the complexity and importance of developing of relations of trust, and thereby gaining "backstage" access, in communities that are generally closed to outsiders. It is argued that gaining authentic ("backstage") access to refugee communities, as well as other communities that have developed a self-protective insularity, is essential if we are to gather data that accurately reflect the actual beliefs, feelings, and experiences of community members. The paper then examines the puzzling lack of discussion regarding issues of trust, access, and the relational context in the literature on refugee mental health. Explanations for this apparent inattention are sought in the influence of the prevailing scientific paradigm that guides most research with refugees, and that shapes the values of the field's "gatekeepers," the editors and reviewers of scholarly journals. Throughout the paper, key points are illustrated with examples drawn from the author's research with refugees from Guatemala, Bosnia, and Afghanistan.