共查询到20条相似文献,搜索用时 31 毫秒
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Radboud J. Duintjer Tebbens Mark A. Pallansch Konstantin M. Chumakov Neal A. Halsey Tapani Hovi Philip D. Minor John F. Modlin Peter A. Patriarca Roland W. Sutter Peter F. Wright Steven G.F. Wassilak Stephen L. Cochi Jong‐Hoon Kim Kimberly M. Thompson 《Risk analysis》2013,33(4):606-646
With the intensifying global efforts to eradicate wild polioviruses, policymakers face complex decisions related to achieving eradication and managing posteradication risks. These decisions and the expanding use of inactivated poliovirus vaccine (IPV) trigger renewed interest in poliovirus immunity, particularly the role of mucosal immunity in the transmission of polioviruses. Sustained high population immunity to poliovirus transmission represents a key prerequisite to eradication, but poliovirus immunity and transmission remain poorly understood despite decades of studies. In April 2010, the U.S. Centers for Disease Control and Prevention convened an international group of experts on poliovirus immunology and virology to review the literature relevant for modeling poliovirus transmission, develop a consensus about related uncertainties, and identify research needs. This article synthesizes the quantitative assessments and research needs identified during the process. Limitations in the evidence from oral poliovirus vaccine (OPV) challenge studies and other relevant data led to differences in expert assessments, indicating the need for additional data, particularly in several priority areas for research: (1) the ability of IPV‐induced immunity to prevent or reduce excretion and affect transmission, (2) the impact of waning immunity on the probability and extent of poliovirus excretion, (3) the relationship between the concentration of poliovirus excreted and infectiousness to others in different settings, and (4) the relative role of fecal‐oral versus oropharyngeal transmission. This assessment of current knowledge supports the immediate conduct of additional studies to address the gaps. 相似文献
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During the last two decades, productivity research and applications have not been given adequate importance when trying to attain excellence in the management of manufacturing enterprises. Recent developments in managerial philosophies Total Quality Management and Business Process Re-engineering , manufacturing technologies Flexible Manufacturing Systems, Computer Integrated Manufacturing, etc. and Information Technology innovations have made the traditional productivity improvement techniques obsolete. This article presents a review consisting of analyses of literature on productivity and a survey of manufacturing enterprises. A five-step preview strategy on productivity is enumerated which provides a meaningful direction towards future productivity research and application. The article is concluded by briefly describing the current research that is being carried out based on the preview strategy evolved. 相似文献
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America and Britain have taken a long time to accept conceptually and pragmatically the post-war economic performance of Japan and other capitalist countries. Our understanding of how to improve our production infrastructure remains inadequate. This paper addresses the critical area of manufacturing organization and restructuring production operations to offer substantial and immediate results. Most of the resources required to become a world class manufacturer are already in place in the UK and the US, yet the organization of these resources remains lacking. The purpose of this paper is to review the importance of productivity and energy conversion within an integrated manufacturing strategy. Current differences in operations management thinking that exist between 相似文献
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Beliefs and the Perception of Risks and Accidents 总被引:3,自引:0,他引:3
Dongo Rémi Kouabenan 《Risk analysis》1998,18(3):243-252
Identifying the causes of accidents is a necessary prerequisite for preventive action. Some research suggests however that the analysis of accidents does not only differ between experts and laymen but that it is also linked to certain characteristics inherent in the analyst and in the social group to which he belongs: beliefs, value systems, norms, experiences in common, attitudes, roles, social and technical practices, etc. Culturally determined bias seems to affect the perception of risk and the causes of accidents. This article presents a certain number of thoughts and results based upon research carried out on causal attributions of traffic accidents in The Ivory Coast (West Africa) and discusses the importance of culture in risk-taking and accident prevention. It shows in particular that fatalistic beliefs and mystical practices influence the perception of accidents and consequently incite one to take more risks and neglect safety measures. 相似文献
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流动性是市场的灵魂,金融创新的目的和结果是提高资产的流动性。2010年3月31日,证监会以促进市场流动性为目的,正式推出融资融券业务试点,并在2011年至2013年先后3次扩大中国A股市场融资融券标的股票的范围。因此,研究中国融资融券是否促进流动性并探究其内在机制具有非常重要的现实意义。
排除股指期货和股指期权等卖空机制的影响,运用面板回归方法和适合政策评估的双重差分法,分别检验2011年至2013年3次融资融券扩容对标的股票流动性的影响,并从融资和融券交易者的短期交易策略和标的股票股东结构变化两个方面探讨买空卖空机制与流动性因果关系的内在机制。
研究结果表明,融资和融券交易的双重引入降低了交易成本和价格影响,提高了标的股票的流动性。随着融资融券业务的深入开展和发展,融资融券标的股票扩容对价格影响方面的流动性的影响越来越强。融资交易者的短期动量交易策略降低了价格影响和交易成本,融券交易者的短期动量交易策略降低了价格影响,而对交易成本影响不显著。由于部分机构投资者退场,偏好短线投机炒作的中大型个体投资者入场,换手率高、流通市值低和特质波动率低等类型的标的股票组合的流动性提高更为明显。
融资融券交易提高标的股票流动性的研究结论补充了已有研究关于买空卖空机制对市场质量影响方面的实证证据,也为中国融资融券业务的发展和完善提供借鉴意义。 相似文献
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一、干部选拔任用工作监督难的原因分析1.监督的主体不够明确。例如,在民主推荐环节,如果有种种条件限制,推荐的范围相对就缩小了许多,这时如果有关人员泄露民主推荐的时间和地点,就很容易出现有关的对象拉推荐票或变相拉票的现象,导致推荐 相似文献
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Safety Investment and the Value of Life and Injury 总被引:1,自引:0,他引:1
The requirement to reduce risk is moderated under British law by the notion of practicability or reasonable practicability. This implies that a balance should be struck, inter alia , between the costs of a risk-reducing measure and its benefits in terms of life-saving and injury avoidance. Clearly, were lives and injuries valued in monetary terms, balances and imbalances would be all the more easily identified. This paper reports on progress on the application of the Relative Utility Loss Approach to the valuation of injuries in the consumer and transportation spheres in the United Kingdom. Although the tools are as yet imperfect, striking accord is noticed between valuations of a range of serious and slight injuries obtained using three health state utility indices of disparate origin. 相似文献
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tpn Jurajda 《LABOUR》2003,17(3):383-389
Abstract. This note provides the motivation to fill a gap in the empirical literature by showing that the optimal firm response to workers’ job search behaviour (Mortensen, Industrial and Labor Relations Review 30: 505–517, 1977) is to lay off those workers with high unemployment insurance and recall workers as they approach expiry of their benefits. 相似文献
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Wolfgang Hora Johanna Gast Norbert Kailer Andrea Rey-Marti Alicia Mas-Tur 《Review of Managerial Science》2018,12(2):411-439
Coopetition (collaboration between competitors) among young firms (i.e. start-ups) and larger, more established firms (i.e. corporates) may be beneficial for both partners as each party typically has something to offer that is missing in the other. Start-ups often develop innovative ideas, are flexible and agile, willing to take risks, and aspire to achieve high growth, but they tend to lack the required resources, capabilities, and knowledge due to their newness and smallness. Corporates have resources, routines, and experience that enable them to work efficiently but lack a certain innovation capability. Research has suggested that coopetition represents an opportunity for start-ups facing restrictions in resources, while corporates benefit from start-ups’ innovative ideas. However, it is yet unknown whether start-ups and corporates engage in coopetition with each other and, if so, how and why they do this. This study seeks to fill this void by exploring the motives of coopeting start-ups and corporates, how they manage their coopetitive relationship, and what implications occur including potential benefits and risks. We present a multiple case study based on qualitative data collected through 70 interviews with Austrian-based start-ups and corporates representing 35 coopetitive partnerships. Discussing the findings based on our data, we propose relationships concerning coopetition and its role to enlarge resource- and technology-bases as well as its role in the development of dynamic capabilities. 相似文献
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Let G be a undirected connected graph. Given g groups each being a subset of V(G) and a number of colors, we consider how to find a subgroup of subsets such that there exists a tree interconnecting all
vertices in each subset and all trees can be colored properly with given colors (no two trees sharing a common edge receive
the same color); the objective is to maximize the number of subsets in the subgroup. This problem arises from the application
of multicast communication in all optical networks. In this paper, we first obtain an explicit lower bound on the approximability
of this problem and prove Ω(g1−ε)-inapproximability even when G is a mesh. We then propose a simple greedy algorithm that achieves performance ratio O√|E(G)|, which matches the theoretical bounds.
Supported in part by the NSF of China under Grant No. 70221001 and 60373012. 相似文献
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Abstract Evaluation of mental effort under industrial conditions encounters both methodological and practical problems mainly because of lack of appropriate indices and difficulties in differentiation between body responses to physical and mental effort. This paper presents a review of laboratory and field research from our laboratories aimed at finding objective indices for discrimination between body responses to mental and physical effort. The laboratory data show that urinary noradrenaline/adrenaline (NA/A) ratio decreases in response to mental tasks and increases in response to physical tasks. Under industrial conditions the predominating component of effort (mental or physical) evokes body response similar to that found during laboratory experiments. Re-analysis of data published in various other papers shows the same pattern of body response. Another possible index for assessment of effort seems to be salivary cortisol which increases in response to both mental and physical tasks. Its deviations from the circadian pattern of excretion may represent a potential criterion for assessment of the emotional component of mental effort. 相似文献
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Evaluation of mental effort under industrial conditions encounters both methodological and practical problems mainly because of lack of appropriate indices and difficulties in differentiation between body responses to physical and mental effort.
This paper presents a review of laboratory and field research from our laboratories aimed at finding objective indices for discrimination between body responses to mental and physical effort. The laboratory data show that urinary noradrenaline/adrenaline (NA/A) ratio decreases in response to mental tasks and increases in response to physical tasks. Under industrial conditions the predominating component of effort (mental or physical) evokes body response similar to that found during laboratory experiments. Re-analysis of data published in various other papers shows the same pattern of body response.
Another possible index for assessment of effort seems to be salivary cortisol which increases in response to both mental and physical tasks. Its deviations from the circadian pattern of excretion may represent a potential criterion for assessment of the emotional component of mental effort. 相似文献
This paper presents a review of laboratory and field research from our laboratories aimed at finding objective indices for discrimination between body responses to mental and physical effort. The laboratory data show that urinary noradrenaline/adrenaline (NA/A) ratio decreases in response to mental tasks and increases in response to physical tasks. Under industrial conditions the predominating component of effort (mental or physical) evokes body response similar to that found during laboratory experiments. Re-analysis of data published in various other papers shows the same pattern of body response.
Another possible index for assessment of effort seems to be salivary cortisol which increases in response to both mental and physical tasks. Its deviations from the circadian pattern of excretion may represent a potential criterion for assessment of the emotional component of mental effort. 相似文献
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