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Clusters,convergence, and economic performance   总被引:1,自引:0,他引:1  
This paper evaluates the role of regional cluster composition in regional industry performance. On the one hand, diminishing returns to specialization in a location can result in a convergence effect: the growth rate of an industry within a region may be declining in the level of economic activity of that industry. At the same time, positive spillovers across complementary economic activities can provide an impetus for agglomeration: the growth rate of an industry within a region may be increasing in the “strength” (i.e., relative presence) of related industries. Building on Porter (1998, 2003), we develop a systematic empirical framework to analyze the role of regional clusters – groups of closely related industries operating within a particular region – in the growth of regional industries. We exploit data from the US Cluster Mapping Project to examine the effects of agglomeration within regional clusters after controlling for convergence at the region-industry level. Our findings suggest that industries located in a strong cluster register higher employment and patenting growth. Regional industry growth also increases with the strength of related clusters in the region and with the strength of similar clusters in adjacent regions. We also find evidence of the complementarity between employment and innovation performance in regional clusters: both the initial employment and patenting strength of a cluster have a separate positive effect on the employment and patenting growth of the constituent industries. Finally, we find that new regional industries emerge where there is a strong cluster. These findings are consistent with multiple types of externalities arising in clusters, including knowledge, skills, and input–output linkages.  相似文献   
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Abstract

The International Physical Activity Questionnaire (IPAQ) has been widely used to assess physical activity in healthy populations. The present study compared physical activity assessed by the long, self-administrated version of the International Physical Activity Questionnaire with physical activity assessed by accelerometry in patients with fibromyalgia. A total of 99 (five men) participants with fibromyalgia completed the International Physical Activity Questionnaire and wore an accelerometer for nine consecutive days. We analysed the correlations of physical activity expressed as min · day?1 of light, moderate, vigorous, and moderate to vigorous (MVPA) intensity, as well as time spent sitting, by the International Physical Activity Questionnaire and accelerometry by Spearman correlations. Bland and Altman plots were performed to verify the agreements between both instruments. The results showed weak yet significant correlations (Rs = 0.15–0.39, all P < 0.05) in all physical activity intensities between the two instruments, except for sedentary time. The highest correlations were observed for physical activity at home or in garden (Rs = 0.297, P < 0.01). The results suggest that the long self-administrated International Physical Activity Questionnaire is a questionable instrument to assess physical activity in patients with fibromyalgia. Therefore, physical activity measurement in fibromyalgia patients should not be limited solely to self-reported measures.  相似文献   
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ABSTRACT: This project evaluates the attitudes of food and health professionals to 3 new food processing technologies that have been developed to respond to consumer demands such as superior taste, longer shelf life, higher nutritional content, health benefits, and environment‐friendly processing. Educational brochures for high pressure (HP), pulsed electric field (PEF), and ohmic heating (OH) processes were developed based on the current literature and consumer information needs. An internet web survey was conducted to determine information needs of food and health professionals and to assess their satisfaction with the data provided in the educational brochures. Health professionals hold a positive attitude toward HP, OH, and PEF. No negative attitudes or discomfort were reported. More people indicated they were very comfortable with HP than any other technology, and as a consequence this technology received the highest scores of likeliness to be included in health professionals' recommendations.  相似文献   
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Gathering information or collecting data is the norm in school systems across the nation. Using that data to make informed decisions should necessitate the use of statistical tools. One such tool, developed by Walter A. Shewhart at Bell Laboratories in 1924, was the ‘Control Chart,’ a means of determining whether a process had been operating in a state of statistical control or operating in the presence of special causes of variation warranting corrective action. Use of control charts has long been an industry practice. As a school district interested in continuous quality improvement, Beloit Turner explored the application of control charts to a number of instructional and non-instructional areas early on in a restructuring project. This article looks at five such explorations.  相似文献   
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