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51.
This article provides a framework for analysing social movements and explaining how collective action can be sustained through networks. Drawing on current relational views of place and space, I offer a spatialized conception of social networks that critically synthesizes network theory, research on social movements, and the literature on the spatial dimensions of collective action. I examine the historic and contemporary network geographies of a group of human rights activists in Argentina (the Madres de Plaza de Mayo) and explain the duration of their activism over a period of more than two decades with regard to the concept of geographic flexibility. To be specific, first I show how, through the practice of place‐based collective rituals, activists have maintained network cohesion and social proximity despite physical distance. Second, I examine how the construction of strategic networks that have operated at a variety of spatial scales has allowed the Madres to access resources that are important for sustaining mobilization strategies. Finally, I discuss how the symbolic depiction of places has been used as a tool to build and sustain network connections among different groups. I conclude by arguing that these three dimensions of the Madres’ activism account for their successful development of geographically flexible networks, and that the concept of geographic flexibility provides a useful template for studies of the duration and continuity of collective action.  相似文献   
52.
Throughout the human life span the functions of several physiological systems dramatically change, including proprioception. Impaired proprioception leads to less accurate detection of body position changes increasing the risk of fall, and to abnormal joint biomechanics during functional activities so, over a period of time, degenerative joint disease may result. Altered neuromuscular control of the lower limb and consequently poor balance resulting from changes in the proprioceptive function could be related to the high incidence of harmful falls that occur in old age subjects. There is evidence of proprioception deterioration with aging. Regular physical activity seems to be a beneficial strategy to preserve proprioception and prevent falls among older subjects. Some studies have demonstrated that the regular physical activity can attenuate age-related decline in proprioception. This paper reviews the evidence of age effects on joint proprioception. We will discuss the possible mechanisms behind these effects and the role of regular physical activity in the attenuation of age-related decline in proprioception.  相似文献   
53.

From 1960 through 1972, Dr. Eugene Saenger oversaw the experimental administration of lethal and near‐lethal doses of radiation to hospital patients at the University of Cincinnati. These experiments were funded by the US Department of Defense, and were specifically designed to acquire military information on the effects of radiation in combat soldiers. Although Saenger's research was terminated after public exposure in 1971, a full and detailed account has not been available until now. The account provided by the President's Advisory Committee on Human Radiation Experiments (ACHRE) in their Final Report of 1995 was incomplete. Our account is based on a reanalysis of all the material available to ACHRE, including highly critical peer reviews by U.C. faculty members. We also present, for the first time, several case histories taken from the medical records of Dr. Saenger's subjects.  相似文献   
54.

Electronic assembly operations are vital to industries such as telecommunications, computers and consumer electronics. This paper presents a constraint analysis methodology for planning and improving electronic assembly operations that draws on concepts from queueing theory, simulation and production planning. The proposed methodology identifies the operational bottleneck and predicts the utilization, throughput and lead time of the assembly line. It also quantifies the relationship between yields and utilization for the assembly operations. A case study is presented that applies the methodology at an Ericsson, Inc., telecommunications equipment assembly facility. The constraint analysis methodology provided valuable decision support as the managers of Ericsson evaluated the costs and benefits of additional production capacity. Although the focus of this paper is electronic assembly operations, the methodology can be applied to general flow line assembly systems with feedback loops for test and rework under dedicated high-volume production.  相似文献   
55.
The successive enlargements of the European Union have implied an important increase of the market where European firms can supply their products. In this paper we analyze the influence of this process on the economic growth of EU members by including the market potential as a scale indicator in a Solow-type model. The main results are: first, the integration in the EU, specially for new members, explain a substantial fraction of subsequent growth (between 15% and 40%); second, this effect diminishes over time; third, the GDP of new members appears to have a greater positive influence than its population; and fourth, peripheral countries and those less open to trade are in a worse position to appropriate such benefits.  相似文献   
56.
Highly pathogenic avian influenza (HPAI) is considered one of the most important diseases of poultry. During the last 9 years, HPAI epidemics have been reported in Asia, the Americas, Africa, and in 18 countries of the European Union (EU). For that reason, it is possible that the risk for HPAI virus (HPAIV) introduction into Spain may have recently increased. Because of the EU free‐trade policy and because legal trade of live poultry was considered an important route for HPAI spread in certain regions of the world, there are fears that Spain may become HPAIV‐infected as a consequence of the legal introduction of live poultry. However, no quantitative assessment of the risk for HPAIV introduction into Spain or into any other EU member state via the trade of poultry has been published in the peer‐reviewed literature. This article presents the results of the first quantitative assessment of the risk for HPAIV introduction into a free country via legal trade of live poultry, along with estimates of the geographical variation of the risk and of the relative contribution of exporting countries and susceptible poultry species to the risk. The annual mean risk for HPAI introduction into Spain was estimated to be as low as 1.36 × 10−3, suggesting that under prevailing conditions, introduction of HPAIV into Spain through the trade of live poultry is unlikely to occur. Moreover, these results support the hypothesis that legal trade of live poultry does not impose a significant risk for the spread of HPAI into EU member states.  相似文献   
57.
We propose a random partition model that implements prediction with many candidate covariates and interactions. The model is based on a modified product partition model that includes a regression on covariates by favouring homogeneous clusters in terms of these covariates. Additionally, the model allows for a cluster‐specific choice of the covariates that are included in this evaluation of homogeneity. The variable selection is implemented by introducing a set of cluster‐specific latent indicators that include or exclude covariates. The proposed model is motivated by an application to predicting mortality in an intensive care unit in Lisboa, Portugal.  相似文献   
58.
59.
Summary.  We discuss the analysis of data from single-nucleotide polymorphism arrays comparing tumour and normal tissues. The data consist of sequences of indicators for loss of heterozygosity (LOH) and involve three nested levels of repetition: chromosomes for a given patient, regions within chromosomes and single-nucleotide polymorphisms nested within regions. We propose to analyse these data by using a semiparametric model for multilevel repeated binary data. At the top level of the hierarchy we assume a sampling model for the observed binary LOH sequences that arises from a partial exchangeability argument. This implies a mixture of Markov chains model. The mixture is defined with respect to the Markov transition probabilities. We assume a non-parametric prior for the random-mixing measure. The resulting model takes the form of a semiparametric random-effects model with the matrix of transition probabilities being the random effects. The model includes appropriate dependence assumptions for the two remaining levels of the hierarchy, i.e. for regions within chromosomes and for chromosomes within patient. We use the model to identify regions of increased LOH in a data set coming from a study of treatment-related leukaemia in children with an initial cancer diagnostic. The model successfully identifies the desired regions and performs well compared with other available alternatives.  相似文献   
60.
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