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81.
82.
Insulin-like growth factor 1 (IGF-1) signaling modulation has been associated with increased lifespan in model organisms, while high levels of circulating interleukin-6 (IL-6) are a marker of disability and mortality. In the prospective, population-based "Treviso Longeva"--TRELONG Study from Italy (n = 668, age range 70-105.5 years at baseline, followed for seven years) we investigated the effects of survival on the IGF-1 receptor (IGF-1R) gene polymorphism rs2229765, the IL-6 gene promoter polymorphism rs1800795, and plasma concentrations of IGF-1 and IL-6, alone or in combination. We found a sex-dependent effect for the IGF-1R rs2229765 polymorphism, as male carriers of the homozygous A/A genotype survived longer, while the IL-6 rs1800795 genotype did not influence overall or sex-specific longevity. Higher IL-6 levels were more detrimental for survival among males than females, while IGF-1 had no dose-response effect. These findings sustain the hypothesis that sex-specific longevity relies on detectable differences in genetic and biochemical parameters between males and females.  相似文献   
83.
Traditional approaches in inventory control first estimate the demand distribution among a predefined family of distributions based on data fitting of historical demand observations, and then optimize the inventory control using the estimated distributions. These approaches often lead to fragile solutions whenever the preselected family of distributions was inadequate. In this article, we propose a minimax robust model that integrates data fitting and inventory optimization for the single‐item multi‐period periodic review stochastic lot‐sizing problem. In contrast with the standard assumption of given distributions, we assume that histograms are part of the input. The robust model generalizes the Bayesian model, and it can be interpreted as minimizing history‐dependent risk measures. We prove that the optimal inventory control policies of the robust model share the same structure as the traditional stochastic dynamic programming counterpart. In particular, we analyze the robust model based on the chi‐square goodness‐of‐fit test. If demand samples are obtained from a known distribution, the robust model converges to the stochastic model with true distribution under generous conditions. Its effectiveness is also validated by numerical experiments.  相似文献   
84.
85.
Forty newborns (M age = 27 hr old) of depressed and nondepressed mothers were habituated to a cold or warm temperature tube by hand. Both groups of infants habituated the temperature of the tube, as indicated by a decrease in holding, and dishabituated, as indexed by an increase in holding when the temperature of the tube changed. However, the newborns of depressed mothers (a) required twice as long to habituate; (b) showed a sensitization effect, as indexed by an increase in holding from the second to the third trial of habituation; and (c) passively handled the objects with their hand.  相似文献   
86.
For the problem of adjudicating conflicting claims, we propose the following method to extend a lower bound rule: (i) for each problem, assign the amounts recommended by the lower bound rule and revise the problem accordingly; (ii) assign the amounts recommended by the lower bound rule to the revised problem. The “recursive-extension” of a lower bound rule is obtained by recursive application of this procedure. We show that if a lower bound rule satisfies positivity then it’s recursive extension singles out a unique awards rule.We then study the relation between desirable properties satisfied by a lower bound rule and properties satisfied by its recursive extension.  相似文献   
87.
Stationarity tests exhibit extreme size distortions if the observable process is stationary yet highly persistent. In this paper we provide a theoretical explanation for the size distortion of the KPSS test for DGPs with a broad range of first order autocorrelation coefficient. Considering a near-integrated, nearly stationary process we show that the asymptotic distribution of the test contains an additional term, which can potentially explain the amount of size distortion documented in previous simulation studies.  相似文献   
88.
Firms are more productive, on average, in larger cities. Two main explanations have been offered: firm selection (larger cities toughen competition, allowing only the most productive to survive) and agglomeration economies (larger cities promote interactions that increase productivity), possibly reinforced by localized natural advantage. To distinguish between them, we nest a generalized version of a tractable firm selection model and a standard model of agglomeration. Stronger selection in larger cities left‐truncates the productivity distribution, whereas stronger agglomeration right‐shifts and dilates the distribution. Using this prediction, French establishment‐level data, and a new quantile approach, we show that firm selection cannot explain spatial productivity differences. This result holds across sectors, city size thresholds, establishment samples, and area definitions.  相似文献   
89.
The present study fills a gap between the benchmarking literature and multi-output based efficiency and productivity studies by proposing a benchmarking framework to analyze total factor productivity (TFP). Different specifications of the Hicks–Moorsteen TFP index are tailored for specific benchmarking perspectives: (1) static, (2) fixed base and unit, and (3) dynamic TFP change. These approaches assume fixed units and/or base technologies as benchmarks. In contrast to most technology-based productivity indices, the standard Hicks–Moorsteen index always leads to feasible results. Through these specifications, managers can assess different facets of the firm's strategic choices in comparison with firm-specific relevant benchmarks and thus have a broad background for decision making. An empirical application for the Spanish banking industry between 1998 and 2006 illustrates the managerial implications of the proposed framework.  相似文献   
90.
Journal of Management and Governance - This paper investigates the case of a hybrid organization located in Northern Italy with the aim of providing an understanding of the role of the context,...  相似文献   
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