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131.
132.
ABSTRACT This article works to dispel the myth that Puerto Rican female urban high school students living in poverty are not capable of performing at high academic levels. This article attempts to counteract these beliefs by describing the four success factors that seven Puerto Rican female high school students attribute to their high academic achievement. These success factors are: (1) religiosity and extracurricular activities as sources of social capital, (2) affirming and maintaining a Puerto Rican identity, (3) maternal influences on students' academic achievement and, (4) the potential for caring teachers and other school staff to influence high academic achievement. Finally, our findings suggest that opportunities for Latinas and other youth of color are still inequitably structured in large, comprehensive high schools. Hence, we argue that schools must continue to bridge the large gap between themselves and the families/communities they serve and utilize the funds of knowledge and social capital that their students already bring to school. 相似文献
133.
Computing maximum likelihood estimates from type II doubly censored exponential data 总被引:1,自引:0,他引:1
Arturo J. fernández José I. Bravo Íñigo De Fuentes 《Statistical Methods and Applications》2002,11(2):187-200
It is well-known that, under Type II double censoring, the maximum likelihood (ML) estimators of the location and scale parameters, θ and δ, of a twoparameter exponential distribution are linear functions
of the order statistics. In contrast, when θ is known, theML estimator of δ does not admit a closed form expression. It is shown, however, that theML estimator of the scale parameter exists and is unique. Moreover, it has good large-sample properties. In addition, sharp
lower and upper bounds for this estimator are provided, which can serve as starting points for iterative interpolation methods
such as regula falsi. Explicit expressions for the expected Fisher information and Cramér-Rao lower bound are also derived.
In the Bayesian context, assuming an inverted gamma prior on δ, the uniqueness, boundedness and asymptotics of the highest
posterior density estimator of δ can be deduced in a similar way. Finally, an illustrative example is included. 相似文献
134.
Guillermo Julián-Moreno Jorge E. López de Vergara Iván González Luis de Pedro Javier Royuela-del-Val Federico Simmross-Wattenberg 《Statistics and Computing》2017,27(5):1365-1382
\(\alpha \)-Stable distributions are a family of probability distributions found to be suitable to model many complex processes and phenomena in several research fields, such as medicine, physics, finance and networking, among others. However, the lack of closed expressions makes their evaluation analytically intractable, and alternative approaches are computationally expensive. Existing numerical programs are not fast enough for certain applications and do not make use of the parallel power of general purpose graphic processing units. In this paper, we develop novel parallel algorithms for the probability density function and cumulative distribution function—including a parallel Gauss–Kronrod quadrature—, quantile function, random number generator and maximum likelihood estimation of \(\alpha \)-stable distributions using OpenCL, achieving significant speedups and precision in all cases. Thanks to the use of OpenCL, we also evaluate the results of our library with different GPU architectures. 相似文献
135.
Gibrán Cruz-Martínez 《Social indicators research》2014,119(3):1295-1317
There is an ongoing debate between focalization and universalization on welfare policies as the best way to develop the welfare state in Latin America and the Caribbean. However, there is a need to develop a measure that exhibits the multidimensional nature of the welfare state, instead of focusing on the social spending dimension. Segura-Ubiergo (The political economy of the welfare state in Latin America: globalization, democracy and development. Cambridge University Press, New York, 2007) constructed a welfare effort index (WEI) to facilitate understand the relative degrees of welfare state development among Latin American countries. The WEI focuses mainly on social spending and ignores the other dimensions of welfare. Based on a comparative analysis of 17 Latin American countries and following the methodology of Segura-Ubiergo, a new index that aims at enriching the WEI was constructed. The new index is multidimensional in that it has eight indicators relating to three dimensions of welfare: social spending, coverage of welfare programs and outcome of welfare institutions. Principal component analysis was used for reducing the indicators into three indexes that represent three proposed dimensions of welfare. The combination of these three indexes gives the multidimensional welfare index. The results of the index account for more than 75 % of the data variance. 相似文献
136.
137.
An appropriate alignment between business strategy, manufacturing strategic objectives and manufacturing capabilities reportedly influences business performance positively. However, few papers empirically analyse this proposition for the case of Porter's generic strategies of cost leadership and differentiation, and none jointly considers all four elements. This paper integrates strategies, capabilities and performance in a single model and proposes that both manufacturing competitive priorities and capabilities, articulated in terms of cost and flexibility, are essential for explaining the link between generic business strategies and business commercial and financial performance. Within this analytic framework, we test whether companies that emphasize one business strategy rather than another achieve a better alignment and superior performance. The analyses conducted with a sample of 148 Spanish manufacturers provide general support for these propositions and contribute to a deeper understanding of the role played by functional strategies in understanding the outcomes of business strategy. 相似文献
138.
139.
János Balogh József Békési Gábor Galambos Gerhard Reinelt 《Journal of Combinatorial Optimization》2014,27(1):115-131
Semi-on-line algorithms for the bin-packing problem allow, in contrast to pure on-line algorithms, the use of certain types of additional operations for each step. Examples include repacking, reordering or lookahead before packing the items. Here we define and analyze a semi-on-line algorithm where for each step at most k items can be repacked, for some positive integer k. We prove that the upper bound for the asymptotic competitive ratio of the algorithm is a decreasing function of k, which tends to 3/2 as k goes to infinity. We also establish lower bounds for this ratio and show that the gap between upper and lower bounds is relatively small. 相似文献
140.
Although the differential treatment of team members by their leader is at the heart of Leader–Member Exchange (LMX) theory, empirical studies exploring the role of within-team LMX differentiation in relation to team outcomes are still relatively scarce. This study among 269 Dutch secondary school teachers from 33 different teams tested the hypotheses that the relationship between LMX differentiation and team commitment, and team performance is moderated by LMX-quality median. Moreover, we hypothesized that team members' perceived dissimilarity regarding work values and orientations would be positively related to within-team LMX differentiation. Teachers completed questionnaires on LMX-quality, dissimilarity, and team commitment, whereas team performance was rated by school principals. Results indeed showed that LMX differentiation is positively related to both outcome variables in teams with a low LMX-quality median only. As expected, more perceived dissimilarity between team members was related to more within-team variability in LMX-scores. These results contribute to knowledge on hypothetical antecedents and consequences of LMX differentiation at the team level. 相似文献