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221.
The relationship between critical incident exposure and resource loss, as conceptualized by Conservation of Resources (COR) theory, in predicting later psychological outcome (e.g., depressive symptoms, anger expression, and state anger) was examined in a sample of 150 fire-emergency workers from a Fire Department in a mid-sized, midwestern city. Additionally, a measure of critical incidents (Critical Incidents Inventory) was developed, and preliminary data on its validity are presented. Results from multiple regression analyses indicated that fire-emergency workers' exposure to critical incidents was directly related to their report of depressive symptoms, outward expression of anger, and state anger. Additionally, results indicated that fire-emergency workers' resource loss was strongly related to their psychological outcome. Results also suggest that resource loss may mediate the impact of critical incident stress exposure on depressive symptoms and the outward expression of anger. These results offer support to applying COR theory to populations under extreme stress.  相似文献   
222.
Despite a growing literature on the collaborative reminiscing of mothers and children, little is known about the kinds of things mothers and children discuss as they recollect shared traumatic experiences. Do mother-child recollections of a traumatic event differ from their recollections of more benign events? To address this question, mother-child dyads (N=29) discussed a traumatic event, namely a devastating tornado, and two nontraumatic events (one that preceded and one that followed the tornado). Each dyad discussed all three events 4-months post-tornado and again 6 months later. Whereas conversations about both event types (traumatic and nontraumatic) varied with children's age, dyads' recollections of the tornado were significantly longer, more narratively coherent, and more complete than their recollections of nontraumatic events. These differences largely endured over the 6-month retention interval.  相似文献   
223.
On August 22, 2005 the U.S. Environmental Protection Agency issued proposed new regulations for radiation releases from the planned permanent U.S. nuclear-waste repository in Yucca Mountain, Nevada. The goal of the new standards is to provide public-health protection for the next million years — even though everyone admits that the radioactive wastes will leak. Regulations now guarantee individual and equal protection against all radiation exposures above the legal limit. Instead E.P.A. recommended different radiation exposure-limits for different time periods. It also recommended using only the arithmetic mean of the dose distribution, to assess regulatory compliance during one time period, but using only the median dose to assess compliance during another period. This piece argues that these two changes — in exposure-limits and in methods of assessing regulatory compliance — have at least four disturbing consequences. The changes would threaten equal protection, ignore the needs of the most vulnerable, allow many fatal exposures, and sanction scientifically flawed dose calculations.  相似文献   
224.
Kinematic (relative phase error), metabolic (oxygen consumption, heart rate) and attentional (baseline and cycling reaction times) variables were measured while participants practised a high energy-demanding, intrinsically unstable 90 degrees relative phase coordination pattern on independent bicycle ergometers. The variables were found to be strongly inter-correlated, suggesting a link between emerging performance stability with practice and minimal metabolic and attentional cost. The effects of practice of 90 degrees relative phase coordination on the performance of in-phase (0 degrees-phase) and antiphase (180 degrees-phase) coordination were investigated by measuring the relative phase attractor layouts and recording the metabolic and attentional cost of the three coordination patterns before and after practice. The attentional variables did not differ significantly between coordination patterns and did not change with practice. Before practice, the coordination performance was most accurate and stable for in-phase cycling, with antiphase next and 90 degrees-phase the poorest. However, metabolic cost was lower for antiphase than either in-phase or 90 degrees-phase cycling, and the pre-practice attractor layout deviated from that predicted on the basis of dynamic stability as an attractor state, revealing an attraction to antiphase cycling. After practice of 90 degrees-phase cycling, in-phase cycling remained the most accurate and stable, with 90 degrees-phase next and antiphase the poorest, but antiphase retained the lowest metabolic energy cost. The attractor layout had changed, with new attractors formed at the practised 90 degrees-phase pattern and its symmetrical partner of 270 degrees-phase. Considering both the pre- and post-practice results, attractors were formed at either a low metabolic energy cost but less stable (antiphase) pattern or at a more stable but higher metabolic energy cost (90 degrees-phase) pattern, but in neither case at the most stable and accurate (in-phase) pattern. The results suggest that energetic factors affect coordination dynamics and that coordination modes lower in metabolic energy expenditure may compete with dynamically stable modes.  相似文献   
225.
Consider the process of raising and lowering the arm in the sagittal plane. Different parts of different muscles operate over different sectors of the angular range. How and why does the nervous system implement this differential muscle activation according to joint angle? We contend that such control depends on the adaptive formation of motor maps. These solve the problem of redundancy in the musculoskeletal system by connecting a relatively small number of cortical columns in the motor cortex to a large number of alpha motor neuron pools. We argue that motor maps are formed such that each functional muscle is activated in proportion to its moment arm about the movement. Because of this the required agonist and antagonist turning forces are generated with a minimum demand for metabolic energy. We know from biomechanical principles that, at any given posture, those muscle fibres that change length most in response to a small joint-angle change are those with the greatest moment arm. Likewise those that change least have the smallest. By establishing a model of the polynomial relationships between the lengths of functional muscles l and the corresponding changes in joint angles theta, the nervous system can generate signals partial differentiallj/ partial differentialthetai (where lj is the length of the jth functional muscle and thetai is the magnitude of the ith elemental movement). These signals create motor maps by modulating the gains of descending motor pathways. As a result, functional muscles are activated in proportion to their moment arms. This reduces the demand for metabolic energy to a minimum. Since moment arms change with joint angle, it also accounts for the experimental observations above. Such motor mapping effectively provides a minimum energy "wired-in" synergy. Established in utero, motor maps are the first stage of synergy formation and provide the basis for the development of subsequent task-dependent synergies.  相似文献   
226.
Radical activist organizations face the complex task of managing their identity so as to draw political attention but also to appear legitimate and thus gain public support. In this article we develop a picture of the identities of Sea Shepherd Conservation Society (SSCS) members, a group mostly known for their direct action against whaling, via a thematic analysis of material from the SSCS website and interviews with SSCS members. In online commentary, founder Captain Paul Watson establishes several deliberately paradoxical notions of who the Sea Shepherds are. We relate these identity statements to interviews with core activists to examine how they manage the identity conflicts resulting from the group identity, such as being seen as “pirates” and “hard lined vegans.” We found that SSCS positions themselves as a diverse and unstructured organization, yet distinctively passionate and willing to take action where others will not. The implications of this research are discussed in relation to the importance of understanding the constraints and conflicts around political activist identities.  相似文献   
227.

The origin of the increase in the stress exponent from n , 2.0 to with decreasing stress in 3 mol% Y 2 O 3 -stabilized tetragonal ZrO 2 has been examined. The present data show that the increase in the n value arises from the existence of a threshold stress that depends on the grain size and temperature. Careful examination of earlier creep data confirms that evaluation of the threshold stress is sensitive to the accuracy of the creep data and the value of n chosen for the compensation of the data. Inspection of the present results and some recent observations of the deformed microstructure suggests that the threshold stress is associated with intragranular dislocation motion.  相似文献   
228.
This analysis considers the link between energy alternatives and cultural attitudes through the postulation of individual and collective energy‐related cognitive maps. The relationship between energy and society is described through the systems approach of General Evolution Theory. The need for cognitive maps is assessed in relation to contemporary global socio‐cultural dynamics. The concept of such maps is explicated and its implication for energy policy formulation is suggested. Finally, the first phase of a research agenda for mapping society's energy‐related cognitive maps through a systems history perspective is presented and discussed.  相似文献   
229.
This case study applies Integral Ecology to analyze the broad range of strategies environmentalists have undertaken to create protected areas and change forest practices in the Great Bear Rainforest, British Columbia, Canada. Rainforest conservation efforts in the region promoted holistic, trans-disciplinary solutions and fostered agreement among diverse stakeholders, modeling an Integral Ecology approach. Environmentalists worked locally and globally, engaging with economic, cultural, political, and scientific systems to create change. The campaign involved transformations at personal and cultural levels that have enabled negotiated solutions involving over twenty million acres of rainforest on British Columbia's coast.  相似文献   
230.
Wind-mills were widely used for grinding corn in the last century in Hungary. The use of solar energy for water heating, taking a bath, shower, and drying crops has had a tradition for a long time. This article presents in what proportion the two types of energy are disposable in the course of the year, how this difference between the simultaneous disposability of the two types of sources of energy changes depending on seasons, and by what a diffusion and variance in a month, a part of a day, or an hour the examined parameters can be characterized.  相似文献   
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