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1.
VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - Institutions—defined as strategies, norms and rules (Ostrom Understanding institutional diversity, Princeton...  相似文献   
2.
We demonstrate that universally redeemed rebates can increase manufacturer profits by reducing the incentives of downstream retailers to hoard inventories when optimal wholesale prices vary predictably over time. By bypassing retailers and making direct contracts with buyers, the manufacturer can increase the variations in effective prices paid by consumers without concomitantly creating larger incentives for retailers to hold inventories. During profitable, high-demand periods, manufacturer revenues are ordinarily constrained by'competition'from retailer inventories, thus limiting profits. However, by selectively offering rebates to consumers while maintaining high wholesale prices, low-demand periods can be accommodated without inducing retailer hoarding.  相似文献   
3.
Treatment of substance abuse among older adults will become increasingly important as the number of aged Americans increases. The abuse of psychoactive substances is a major contributor to excess morbidity, mortality, and homelessness among persons of all ages and socioeconomic strata regardless of race or ethnicity. Alcohol and tobacco accountfor the majority of substance abuse-related death and disability in the United States; the former through cerebrovascular and hepatic disease, accidents and violence, the latter through chronic pulmonary disease and malignancy. Patterns of substance abuse in late life are substantially different from those observed among younger adults. However, treatment may be less challenging. Effective diagnosis and treatment requires a nonpunitive, supportive, but persistent approach. This means the capacity to collect a substance intake history and the ability to formulate a treatment plan or referral strategy to an addiction specialist or residential treatment setting. It is also important for the practitioner to manage negative feelings toward patients who decline treatment or who are chronic abusers.  相似文献   
4.
Previous studies have shown that teachers’ gestures are beneficial for student learning. In this research, we investigate whether teachers’ gestures have comparable effects in face-to-face live instruction and video-based instruction. We provided sixty-three 7–10 year old students with instruction about mathematical equivalence problems (e.g., 3 + 4 + 5 = __ + 5). Students were assigned to one of four experimental conditions in a 2 × 2 factorial design that varied (1) instruction medium (video vs. live), and (2) instruction modality (speech vs. speech + gesture). There was no main effect of medium: The same amount of learning occurred whether instruction was done live or on video. There was a main effect of modality: Speech instruction accompanied by gesture resulted in significantly more learning and transfer than instruction conveyed through speech only. Gesture’s effect on instruction was stronger for video instruction than live instruction. These findings suggest that there may be a limit to gesture’s role in communication that results in student learning.  相似文献   
5.
A statistical quality control chart is an important tool of the statistical process control, which is widely used to control and monitor a production process. The CUSUM chart is designed to detect a specific shift, provided that the shift size is known in advance. In practice, however, shift sizes are rarely known. It is then customary to use an adaptive CUSUM chart, which can effectively detect a range of shift sizes. In this paper, we enhance the sensitivities of the improved adaptive CUSUM mean charts using an auxiliary-information-based (AIB) mean estimator. The run length performances of the proposed charts are compared with those of the AIB adaptive and non-adaptive CUSUM charts in terms of the average run length (ARL), extra quadratic loss, and integral relative ARL. These run length comparisons reveal that the proposed charts are more sensitive than the existing charts when detecting different kinds of shift in the process mean. An example is given to demonstrate the implementation of existing and proposed charts.  相似文献   
6.
In this paper, measurements from experiments and results of a finite element analysis (FEA) are combined in order to compute accurate empirical models for the temperature distribution before a thermomechanically coupled forming process. To accomplish this, Design and Analysis of Computer Experiments (DACE) is used to separately compute models for the measurements and the functional output of the FEA. Based on a hierarchical approach, a combined model of the process is computed. In this combined modelling approach, the model for the FEA is corrected by taking into account the systematic deviations from the experimental measurements. The large number of observations based on the functional output hinders the direct computation of the DACE models due to the internal inversion of the correlation matrix. Thus, different techniques for identifying a relevant subset of the observations are proposed. The application of the resulting procedure is presented, and a statistical validation of the empirical models is performed.  相似文献   
7.
Abstract The directions of net migration and population redistribution in the U.S. have switched from nonmetropolitan deconcentration during the 1970s, to metropolitan concentration during the 1980s, and back to deconcentration once again in the early 1990s. The complex causes of these distribution shifts are thought to involve both structural reconfigurations of economic activities that affect the location of opportunities and residential preferences that are tied more closely to amenities and quality of life considerations. This paper uses comparable data from three representative sample surveys of the U.S. population to update and extend earlier research on the preferential basis of redistribution trends. Our analysis does not support the view that shifts in the direction of residential preferences during 1972–1992 tend to coincide with shifts in metropolitan-nonmetropolitan net migration and population redistribution. Rather, a consistent finding across all three surveys is that most people prefer their current residence type, and those who do not are almost twice as likely to prefer lower rather than higher density settings. These findings support the importance of preferences to explanations of recent population trends, but these preferences are not in isolation from the economic contexts in which they occur.  相似文献   
8.
Motivated by a real-life problem, we develop a Two-Stage Cluster Sampling with Ranked Set Sampling (TSCRSS) design in the second stage for which we derive an unbiased estimator of population mean and its variance. An unbiased estimator of the variance of mean estimator is also derived. It is proved that the TSCRSS is more efficient—in the sense of having smaller variance—than the conventional two-stage cluster simple random sampling in which the second-stage sampling is with replacement. Using a simulation study on a real-life population, we show that the TSCRSS is more efficient than the conventional two-stage cluster sampling when simple random sampling without replacement is used in both stages.  相似文献   
9.
Zero-inflated models are commonly used for modeling count and continuous data with extra zeros. Inflations at one point or two points apart from zero for modeling continuous data have been discussed less than that of zero inflation. In this article, inflation at an arbitrary point α as a semicontinuous distribution is presented and the mean imputation for a continuous response is discussed as a cause of having semicontinuous data. Also, inflation at two points and generally at k arbitrary points and their relation to cell-mean imputation in the mixture of continuous distributions are studied. To analyze the imputed data, a mixture of semicontinuous distributions is used. The effects of covariates on the dependent variable in a mixture of k semicontinuous distributions with inflation at k points are also investigated. In order to find the parameter estimates, the method of expectation–maximization (EM) algorithm is used. In a real data of Iranian Households Income and Expenditure Survey (IHIES), it is shown how to obtain a proper estimate of the population variance when continuous missing at random responses are mean imputed.  相似文献   
10.
This paper focuses on the study of the optimal control problem of the unstable stochastic lattice gas of prey–predator model with pair-approximation. The Pontryagin minimum procedure is used to derive the optimal behaviour of the proposed system that makes it trajectory closer to its general equilibrium states with respect to a selected performance measure during a specified period of time T. Wide numerical simulations and illustrations are presented in graphs and tables.  相似文献   
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