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21.
为研究石家庄市在"利剑斩污"行动管控期和非管控期挥发性有机物(VOCs)的污染特性变化,在2个时间段内对石家庄市3个国控点进行采样分析。通过苏玛罐(SUMMA罐)进行样品采集,利用气相色谱/质谱联用(GC/MS)仪对石家庄市区3个国控点的VOCs进行定性定量检测分析。结果表明,监测期间主要的特征污染物是二氯甲烷、二氯丙烷、苯和甲苯。与非管控期间相比,管控期间各污染物的质量浓度均有所降低,总VOCs平均质量浓度降低45.107μg/m~3,二氯甲烷质量浓度降低8.796μg/m~3,二氯丙烷质量浓度降低3.750μg/m~3,苯质量浓度降低18.285μg/m~3,甲苯质量浓度降低16.895μg/m~3。大气环境调控策略的实施,有效降低了VOCs浓度,减少了空气污染程度,空气质量改善效果显著。"利剑斩污"行动期间采取的相关举措,对于制定常态化下VOCs的防治对策具有一定的参考价值。  相似文献   
22.
In a series of recent papers, Domowitz, Hubbard and Peterson (DHP) have explored the temporal behavior of price-cost margins in a panel of 284 four-digit SIC industries. This paper reexamines DHP's apparent finding of more procyclical margins in concentrated industries, concluding that it is not robust. The result appears to arise from long-run trend correlations between margin and demand levels, rather than from short-run cyclical effects. Consistent with DHP, prices are found to be stickier and unit costs more countercyclical in concentrated industries. However, (1) an omitted variables bias is uncovered which substantially reduces the estimated cyclical effect on costs, and (2) prices are found to be more flexible in low concentration, low-PCM industries than DHP estimate. With prices more responsive to growth in demand and a countercyclical effect on cost of substantially lower magnitude, margins are thus estimated to bemore procyclical in less concentrated industries. This finding explains the relative rise in low concentration margins in the sixties which, in turn, helps account for the declining significance of the cross-sectional concentration-margins relationship.I would like to acknowledge helpful comments from Roy Rotheim, and two anonymous reviewers.  相似文献   
23.
周丹 《特区经济》2007,(8):128-129
多元化战略是企业广为采用和备受非议的战略,股权集中度与企业多元化的关系研究是近年来公司治理领域研究的重点和热点问题之一。本文以筛选出符合要求的531家中国上市公司样本为研究对象。对股权集中度与企业多元化变量的实证分析。结果表明:股权集中度,包括第一大股东持股比例与企业多元化呈显著U型曲线关系。  相似文献   
24.
One of the main issues with the concept of ecosystem services is its absence on the ground in concrete operational decision-making contexts; that is, an implementation gap. In this study, we investigated if this gap could be overcome through the use of open-source data and free tools, and the adoption of a short-term participatory process. We tested these methods in the context of a project in the urban metropolitan area of Bordeaux (Communauté urbaine de Bordeaux: CUB) in France. The ecosystem services were defined using a participatory approach involving local stakeholders, and then selected scenarios were simulated to test the impact of various development or conservation plans. The study addressed three main questions: (1) Is it possible to adopt a simple methodological approach that overcomes the implementation gap through the development of a user-friendly and inclusive method? (2) What is the added value of a participatory approach? (3) With regards to four scenarios in this territory, what are the ES trends in the selected biophysical and monetary indicators, and will knowledge of these trends help planners to shape a sustainable trajectory for the territory?  相似文献   
25.
An emerging body of literature has demonstrated that corporate philanthropy can be an important part of a company’s business strategy. However, we know relatively little about how companies allocate philanthropic resources to achieve their strategic targets. Using geographical distribution data on corporate philanthropy in China from 2009 to 2016, we provide robust evidence of companies’ revenue-driven regional favoritism. Specifically, companies donate more to regions where they obtain revenue than to other regions. Further evidence suggests that this revenue-driven regional favoritism may have both reputational and political motivations. Further analysis suggests that China’s targeted poverty alleviation policy has compromised revenue-driven regional favoritism while increasing the amount of money donated to poor regions. Overall, we enrich understanding of decision-making on corporate philanthropy. We also demonstrate that companies can use the geographical distribution of corporate philanthropy strategically to obtain consumer and government favor in regions where they operate. The results also provide evidence at the micro company level of the effect of China’s implementation of a targeted poverty alleviation policy.  相似文献   
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27.
In the last decades, supply chains have increasingly transcended national boundaries developing into global supply chains. Along with the many opportunities arising from international sourcing and the extended commercial presence over the world, the management of a globally dispersed supply chain is highly complex. A key issue to consider when dealing with the global supply chain design is the location of facilities, not only with respect to firms' owned facilities but also the supply and distribution side as factors that affect supply chain complexity and operational performance. This paper sets out a methodological framework to characterize the geographical configuration of a firm's suppliers and retailer networks. Quantitative indexes of network spatial concentration and relative proximity measures based on a nonparametric kernel density estimator are developed to identify both intra- and inter-firm patterns between the supply and point of sales' distributions. The method is first described by means of a series of theoretical-illustrative examples and exemplified by analyzing the geographical dispersion of four practical cases from the fashion-textile industry (i.e., Adidas, Benetton, C&A, and Puma). Subsequently, managerial implications and potential use of the metrics are discussed, showing how the proposed approach can support researchers and practitioners to improve supply chain location decisions and logistic integration, and evaluate changes in either the purchasing or distribution strategy.  相似文献   
28.
由于目前关于建筑行业资质管理对建筑产业的有效性存在正反两方面不同看法,双方虽有定性理论分析和国外资质管理根据,但是无法说明资质管理对我国建筑产业整体收益具体影响,因而从个体企业行为角度出发,根据多智能体理论,使用Netlogo建模平台,建立中国建筑业的交易行为互动流程,模拟运行建筑产业执行或不执行资质管理的情况,观察并分析论证了资质管理有利于提高中国建筑产业收益能力。此外,在模拟过程中发现资质管理对产业结构也存在影响。  相似文献   
29.
This paper empirically investigates the main drivers of airline network concentration in an air transport market subject to rapid growth. We consider the Brazilian air transport industry of the 2000s, in which network concentration rapidly increased and was followed by a period of massive flight delays and cancelations, which resulted in the “big blackout” of 2006–2007. We develop an econometric model of network concentration, accounting for demand, cost and competition variables that may affect the propensity of carriers to concentrate flights and passenger connections on a few airports of a network. The main focus of the paper is on the relation between networks leading to the problems of the blackout episode. We investigate the dynamic pattern of the evolution of concentration before and after the abnormal period of operations and find that concentration began to rise at least six quarters before, and persisted at a high level until two quarters after the blackout – and then plunged steeply toward the end of the decade. We believe that our analysis contributes to an improved understanding of the behavior of air transport systems subject to network concentration and congestion. With respect to methodology, we suggest and employ the use of alternative measures of network concentration to check the robustness and validity of our results.  相似文献   
30.
The role of corporate social responsibility (CSR) in shaping consumer perception and attitude has received many attentions both in the academia and practitioner world. While this domain has invited numerous research, but research highlighting how consumers react toward learning the size of a firm conducting CSR and geographical scope of the CSR impact is still scarce. We investigate how consumers shape their attitude and consumption behavior after knowing that the CSR action is done by a small, locally-owned business that brings impact to the local community through an experimental study. Our study adds a shade in understanding how the effect of a firm size and geographical scope of CSR impact might increase consumers' favorable attitude and behavior toward the business and its products. Our findings show that when consumers learn that the firm conducting CSR is a small, locally-owned (in coffee shop business) that directs its action toward local beneficiaries, they demonstrate more favorable attitudes toward the action and the firm, which manifest in the form of better intentions to acquire the product as well as willingness to pay premium prices for it. Our findings confirm the US consumers' love affair with local businesses, in particular. While the findings generally benefit small, locally-owned businesses, they also suggest recommendations for large, multinational businesses to design their marketing strategy in an attempt to increase favorable reactions from consumers.  相似文献   
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