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排序方式: 共有130条查询结果,搜索用时 15 毫秒
121.
Tobias Morat Daniela Kroeger Heinz Mechling 《European review of aging and physical activity》2013,10(2):117-125
Locomotion is an essential component of independence and well-being at old age. Performance deficits in the gait of older adults most often become evident on multisurface and varying terrains. Research results substantiate that falls occur in everyday movement situations that are characterized by instability. A test track, the Multisurface Obstacle Test for Older Adults (MSOT), was developed to diagnose individual performance. The 10-m track consists of different obstacles and varying surfaces, which represent everyday movement situations in a compact way. Twenty-nine untrained, healthy older adults (11 men, 18 women) were tested on three different days at 1-week intervals in a test–retest design by the same conductor. Mean age of the participants was 68.8?±?5.3 years with a mean body mass index of 24.4?±?2.5 kg/m2. The measured outcome variable was the required time (seconds) on the MSOT. The feasibility for the tested sample of untrained older adults was very good. The MSOT was undertaken safely by the participants, and no falls occurred. The range of the mean for time was between 8.12?±?1.53 s and 9.00?±?1.62 s. Regarding intertrial reliability, mean differences (MD) of ?3.39 to ?5.52 % and coefficients of variation (CV) of 2.72 to 4.19 % between the first and second trials and MD of ?0.69 to ?0.85 % and CV of 2.57 to 4.54 % over the three test sessions were observed. The correlation coefficients between the sessions were .92–.98. There were significant differences (p?<?.05) between the first and second trials of each session and between the first and second sessions. The smallest detectable differences (SDD) revealed that a small improvement is enough to detect changes in performance in the MSOT. Selecting tasks from real-life situations of older adults contributes to substantiate practical usability of the MSOT. The measured time on the MSOT showed high relative and absolute reliability in the target group of older adults between 60 and 80 years. 相似文献
122.
Multinational corporations (MNC) search increasingly for lead market knowledge and technological expertise around the globe. We investigate whether their subsidiaries gain access to these valuable sources of host country knowledge to the same degree as domestic rivals. We develop a theoretical framework for “why” and “how” a lack of embeddedness and legitimacy (liability of foreignness) may translate into additional obstacles for foreign subsidiaries. We test these hypotheses empirically using a broad dataset of more than 1100 firms in Germany. We find that MNCs can compete on an equal footing with host country competitors when it comes to generating impulses for innovations from universities. They are significantly challenged by liabilities of foreignness, though, when host country customers are involved. The disadvantages are especially pronounced when the host country industry is at the technological forefront. We suggest that the disadvantages arising from liability of foreignness in the host country are especially relevant when promising lead customers have to be identified and their tacit and often unarticulated impulses have to be transferred, understood and prioritized. Management recommendations are developed on the basis of these results. 相似文献
123.
Jamison M. Day P. Daniel Wright Tobias Schoenherr Munirpallam Venkataramanan Kevin Gaudette 《Omega》2009
This paper investigates cyclical inventory replenishment for a company's regional distribution center that supplies, distributes, and manages inventory of carbon dioxide (CO2) at over 900 separate customer sites in Indiana. The company previously experienced high labor costs with excessive overtime and maintained a regular back-log of customers experiencing stockouts. To address these issues we implemented a three-phase heuristic for the cyclical inventory routing problem encountered at one of the company's distribution centers. This heuristic determines regular routes for each of three available delivery vehicles over a 12-day delivery horizon while improving four primary performance measures: delivery labor cost, stockouts, delivery regularity, and driver–customer familiarity. It does so by first determining three sets of cities (one for each delivery vehicle) that must be delivered to each day based on customer requirements. Second, the heuristic assigns the remaining customers in other cities to one of the three “backbone routes” determined in phase 1. And third, it balances customer deliveries on each daily route over the schedule horizon. Through our methodology, we were able to significantly reduce overtime, driving time, and labor costs while improving customer service. 相似文献
124.
Alexander N. Donev Randy Tobias Farinaz Monadjemi 《Journal of statistical planning and inference》2008
Confirmatory bioassay experiments take place in late stages of the drug discovery process when a small number of compounds have to be compared with respect to their properties. As the cost of the observations may differ considerably, the design problem is well specified by the cost of compound used rather than by the number of observations. We show that cost-efficient designs can be constructed using useful properties of the minimum support designs. These designs are particularly suited for studies where the parameters of the model to be estimated are known with high accuracy prior to the experiment, although they prove to be robust against typical inaccuracies of these values. When the parameters of the model can only be specified with ranges of values or by a probability distribution, we use a Bayesian criterion of optimality to construct the required designs. Typically, the number of their support points depends on the prior knowledge for the model parameters. In all cases we recommend identifying a set of designs with good statistical properties but different potential costs to choose from. 相似文献
125.
126.
ABSTRACTWhile the fact that the implementation of migration policies fails to perfectly manage migration is well known, the actual dynamics of policy implementation have received little attention to date. A serious engagement with this phenomenon requires a move beyond policy texts and political intentions, and towards a ‘migration regime’ perspective that pays attention to the inherent contradictions, conflicts of interest and competing logics within migration control practices. This collection posits a multi-actor perspective that includes state agents, migrants and non-state actors alike and proposes three key factors that require a closer examination: competing institutional logics, discretionary practices and migrants’ agency. Based on original empirical research, the contributions of this collection ‘zoom in’ on specific asymmetrical negotiations over the right to enter or remain in Europe, and focus on the institutional logics and interplay between the different actors involved. 相似文献
127.
Tobias G. Eule 《Journal of ethnic and migration studies》2018,44(16):2780-2795
ABSTRACTThis paper sheds light onto the processes of controlling irregular migration in Germany, based on ethnographic fieldwork with immigration officials, police forces, home office bureaucrats and non-state actors. Several studies have examined the policies and tools of migration control available to state officials and contracted third parties and generally found a trend towards greater restrictiveness and securitisation with regard to irregular migration. However, relatively few analyse their actual implementation. This paper seeks to fill this gap, and to act as slight corrective by highlighting the relatively limited nature by which migration control was exercised. In fact, the practice of detecting, identifying, detaining and deporting irregular immigrants was far removed from the politicised discourse that surrounds it in the public sphere and academia, and instead influenced by pragmatism and nonchalance. However, in contrast to explanations that see lenience towards irregular migrants as motivated by economic factors, here the limits of migration control were directly related to officials’ sense of duty, as well as working conditions and a lack of institutional oversight. In this sense, the enhanced possibilities of control through new means of surveillance and data collection are in fact restricted because officials might just not be bothered to use them. 相似文献
128.
Comparative Human Health Impact Assessment of Engineered Nanomaterials in the Framework of Life Cycle Assessment
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Wouter Fransman Harrie Buist Eelco Kuijpers Tobias Walser David Meyer Esther Zondervan‐van den Beuken Joost Westerhout Rinke H. Klein Entink Derk H. Brouwer 《Risk analysis》2017,37(7):1358-1374
For safe innovation, knowledge on potential human health impacts is essential. Ideally, these impacts are considered within a larger life‐cycle‐based context to support sustainable development of new applications and products. A methodological framework that accounts for human health impacts caused by inhalation of engineered nanomaterials (ENMs) in an indoor air environment has been previously developed. The objectives of this study are as follows: (i) evaluate the feasibility of applying the CF framework for NP exposure in the workplace based on currently available data; and (ii) supplement any resulting knowledge gaps with methods and data from the li fe c ycle a pproach and human r isk a ssessment (LICARA) project to develop a modified case‐specific version of the framework that will enable near‐term inclusion of NP human health impacts in life cycle assessment (LCA) using a case study involving nanoscale titanium dioxide (nanoTiO2). The intent is to enhance typical LCA with elements of regulatory risk assessment, including its more detailed measure of uncertainty. The proof‐of‐principle demonstration of the framework highlighted the lack of available data for both the workplace emissions and human health effects of ENMs that is needed to calculate generalizable characterization factors using common human health impact assessment practices in LCA. The alternative approach of using intake fractions derived from workplace air concentration measurements and effect factors based on best‐available toxicity data supported the current case‐by‐case approach for assessing the human health life cycle impacts of ENMs. Ultimately, the proposed framework and calculations demonstrate the potential utility of integrating elements of risk assessment with LCA for ENMs once the data are available. 相似文献
129.
Taking the example of recognized refugees in rural Germany, and following the housing pathways approach, the paper addresses the complex interplay of individual and family-related residential preferences over time as well as structural factors regarding access to housing and associated settlement and integration. Results are from a long-term empirical study that encompassed both refugees’ and local actors’ views. Mechanisms and practices of exclusion that prevent refugees from accessing appropriate private housing are related to the negotiation of residential preferences about where and how to live, as well as to structural aspects such as the pattern of local housing markets, accessibility of infrastructures or the unwillingness of landlords to let to refugees. The paper concludes to highlight the role of place in housing trajectories and the significance of social resources within refugees' practices and local intermediaries' strategies to overcome exclusion and provision of access to rural housing. 相似文献
130.
Gaohong Dong Bo Huang Johan Verbeeck Ying Cui James Song Margaret Gamalo-Siebers Duolao Wang David C. Hoaglin Yodit Seifu Tobias Mütze John Kolassa 《Pharmaceutical statistics》2023,22(1):20-33
Conventional analyses of a composite of multiple time-to-event outcomes use the time to the first event. However, the first event may not be the most important outcome. To address this limitation, generalized pairwise comparisons and win statistics (win ratio, win odds, and net benefit) have become popular and have been applied to clinical trial practice. However, win ratio, win odds, and net benefit have typically been used separately. In this article, we examine the use of these three win statistics jointly for time-to-event outcomes. First, we explain the relation of point estimates and variances among the three win statistics, and the relation between the net benefit and the Mann–Whitney U statistic. Then we explain that the three win statistics are based on the same win proportions, and they test the same null hypothesis of equal win probabilities in two groups. We show theoretically that the Z-values of the corresponding statistical tests are approximately equal; therefore, the three win statistics provide very similar p-values and statistical powers. Finally, using simulation studies and data from a clinical trial, we demonstrate that, when there is no (or little) censoring, the three win statistics can complement one another to show the strength of the treatment effect. However, when the amount of censoring is not small, and without adjustment for censoring, the win odds and the net benefit may have an advantage for interpreting the treatment effect; with adjustment (e.g., IPCW adjustment) for censoring, the three win statistics can complement one another to show the strength of the treatment effect. For calculations we use the R package WINS, available on the CRAN (Comprehensive R Archive Network). 相似文献