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51.
中国科学院神农架生物多样性定位研究站   总被引:1,自引:0,他引:1       下载免费PDF全文
正中国科学院神农架生物多样性定位研究站(以下简称"神农架站")于1994年建站,隶属于中国科学院植物研究所,现为中国科学院生态系统研究网络(CERN)和国家野外科学观测研究网络(CNERN)成员,长江三峡工程生态与环境监测网络的重点站。神农架站区位于鄂西神农架地区(东经110°03′—110°34′,北纬31°19′—31°36′,海拔420—3105m),属秦巴山地常绿—落叶阔叶林生态区,以北亚热带常绿落叶阔叶混交林为主,代表了秦巴山地地带性森林生态系统类型。神农架地区植被垂直带谱完整,不仅是全球14个  相似文献   
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Abstract

This article analyzes the determinants of public engagement on the Facebook pages of municipalities. The sample consists of 170 Italian and Spanish municipalities that used Facebook in 2014. The findings show that posting a lot of information on municipal Facebook pages does not increase the engagement of citizens. Also, frequent posting of information per se does not engage public engagement. However, if the posts are published when public can pay attention to them (e.g., off days), the likelihood of public engagement increases. Furthermore, the citizens’ engagement on municipal Facebook page depends on the level of citizens’ income – there is a negative relationship between citizens’ income and the level of participation.  相似文献   
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BackgroundDespite the well-established health benefits of physical activity (PA) for young people (aged 4–19 years), most do not meet PA guidelines. Policies that support PA in schools may be promising, but their impact on PA behavior is poorly understood. The aim of this systematic review was to ascertain the level and type of evidence reported in the international scientific literature for policies within the school setting that contribute directly or indirectly to increasing PA.MethodsThis systematic review is compliant with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Six databases were searched using key concepts of policy, school, evaluation, and PA. Following title and abstract screening of 2323 studies, 25 progressed to data synthesis. Methodological quality was assessed using standardized tools, and the strength of the evidence of policy impact was described based on pre-determined codes: positive, negative, inconclusive, or untested statistically.ResultsEvidence emerged for 9 policy areas that had a direct or indirect effect on PA within the school setting. These were whole school PA policy, physical education, sport/extracurricular PA, classroom-based PA, active breaks/recess, physical environment, shared use agreements, active school transport, and surveillance. The bulk of the evidence was significantly positive (54%), 27% was inconclusive, 9% was significantly negative, and 11% was untested (due to rounding, some numbers add to 99% or 101%). Frequency of evidence was highest in the primary setting (41%), 34% in the secondary setting, and 24% in primary/secondary combined school settings. By policy area, frequency of evidence was highest for sport/extracurricular PA (35%), 17% for physical education, and 12% for whole school PA policy, with evidence for shared use agreements between schools and local communities rarely reported (2%). Comparing relative strength of evidence, the evidence for shared use agreements, though sparse, was 100% positive, while 60% of the evidence for whole school PA policy, 59% of the evidence for sport/extracurricular PA, 57% of the evidence for physical education, 50% of the evidence for PA in classroom, and 50% of the evidence for active breaks/recess were positive.ConclusionThe current evidence base supports the effectiveness of PA policy actions within the school setting but cautions against a “one-size-fits-all” approach and emphasizes the need to examine policy implementation to maximize translation into practice. Greater clarity regarding terminology, measurement, and methods for evaluation of policy interventions is needed.  相似文献   
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This paper analyzes the effects that the 2012 VAT rise in Spain had on household’ demand for cultural goods and services. Household’ demands are modeled as a two-stage QUAIDS. After estimating price and expenditure elasticities, and the pass-through parameter associated with the reform, our results show that the individual welfare loss and the increment in the tax bill increase, but less than proportionately, with income. Consequently, the reform can be considered as regressive. Relating the effects of the VAT reform to households’ incomes also implies a low quantitative effect, because of the low proportion of total household expenditure that cultural expenditure represents. From a social perspective, the size of the induced welfare loss would positively depend on society’s inequality aversion. Regardless of the latter, it cannot be concluded whether the reform would have increased or reduced inequality in the distribution of cultural spending. Our results prove qualitatively robust to alternative values of the pass-through parameter.  相似文献   
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科技全球化及中国的机遇、挑战与对策   总被引:16,自引:1,他引:16  
全球化的浪潮已经席卷世界各个角落.无论政府、企业还是个人都不可避免地受到全球化的冲击.而政治、经济、文化、科技等概念也越来越多地突破国家的界限而被刻上全球化的烙印.  相似文献   
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Near infrared reflectance (N1R) spectroscopy is as a rapid, convenient and simple nondestructive technique useful for quantifying several soil properties. This method was used to estimate nitrogen (N) and organic matter (OM) content in a soil of Zhejiang Province, Hangzhou County. A total of 125 soil samples were taken from the field. Ninety-five samples spectra were used during the calibration and cross validation stage. Thirty samples spectra were used to predict N and OM concentration. NIR spectra of these samples were correlated using partial least square regression. The regression coefficients between measured and predicted values of N and OM was 0.92 and 0.93, and SEP (standard error of prediction) were 3.28 and 0.06, respectively, which showed that NIR method had potential to accurately predict these constituents in this soil. The results showed that NIR spectroscopy could be a good tool for precision farming application.  相似文献   
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The study explores the consequences, for participating schools, of the implementation of a system for the identification and selection of academically talented students, in the context of an extracurricular enrichment program operating at Pontificia Universidad Católica de Chile. The participants were 73 students, 50 teachers, and seven members of the school administration, in seven schools. Data were collected through interviews and focus groups. The results indicated that the identification and selection processes have mostly positive effects on teachers and students. Some potentially negative effects were also detected for the classmates of the talented students, which relate mainly to the manner in which information was handled. Possible implications of these findings for this program for talented children and other similar programs are discussed.  相似文献   
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