Mortality modeling: A review

Looking at survival in terms of biological indicators of aging has given rise to various models of mortality, some of which we review here. The most notable models are that of Strehler and Mildvan, which relates the force of mortality to the ability of organisms to compensate for stress, and that of Sacher and Trucco, which describes the role played by homeostatic forces in shaping the age‐specific pattern of mortality. The analysis of longitudinal data in aging studies now incorporates the notions of heterogeneity and frailty, as well as that of changes in the “repair capacity”; of organisms. Furthermore, attention is now being paid to evolutionary theory and to models of senescence. These models and directions for further research are discussed.     

One country,three populations: Trust in police among migrants,villagers, and urbanites in China

While the past decade has witnessed the burgeoning of research on public assessments of the police in China, marginalized social groups have rarely been considered in this line of inquiry. Using data collected from migrant workers, rural villagers, and urban dwellers, this study assesses whether Chinese perceptions of the police are distinguishable along procedural-based trust and outcome-based trust and whether expressive concerns and instrumental concerns are predictive of trust in the police. Findings show that Chinese citizens tend to conflate procedural-based trust and outcome-based trust. Expressive concerns play a more important role than instrumental concerns, with such expressive variables as trust in neighborhood residents committee, perceived law and order, and quality of life influencing trust in the police. Public perceptions of police trustworthiness are also significantly linked to media influence. Directions for future research are discussed.     

Russia 2020

The authors describe four idealized alternative scenarios for Russia in 2020—Kremlin Gambit, Fortress Russia, Russian Mosaic, and New Dream—and analyze the views of focus-group participants concerning their probability and desirability. They find that these views are influenced only marginally by electoral preferences.     

Mexican Migration Networks in the United States, 1980–20001

Between 1980 and 2000, about 1.2 million Mexican immigrants settled in 47 new settlement states. In the past, these immigrants would have settled in California, Texas, or Illinois, the three traditional states for Mexican settlement. Explaining this dispersion, the network saturation theory claims that high‐volume migration of Mexicans finally saturated the housing and job opportunities of Mexicans in traditional states and especially in Los Angeles. High rents and low wages then encouraged Mexican immigrants to select new states for settlement. This article subjects the network saturation theory to a rigorous reanalysis using new evidence. The empirical results tend to confirm the network saturation theory.     

A goodness-of-fit test for multivariate multiparameter copulas based on multiplier central limit theorems

Recent large scale simulations indicate that a powerful goodness-of-fit test for copulas can be obtained from the process comparing the empirical copula with a parametric estimate of the copula derived under the null hypothesis. A first way to compute approximate p-values for statistics derived from this process consists of using the parametric bootstrap procedure recently thoroughly revisited by Genest and Rémillard. Because it heavily relies on random number generation and estimation, the resulting goodness-of-fit test has a very high computational cost that can be regarded as an obstacle to its application as the sample size increases. An alternative approach proposed by the authors consists of using a multiplier procedure. The study of the finite-sample performance of the multiplier version of the goodness-of-fit test for bivariate one-parameter copulas showed that it provides a valid alternative to the parametric bootstrap-based test while being orders of magnitude faster. The aim of this work is to extend the multiplier approach to multivariate multiparameter copulas and study the finite-sample performance of the resulting test. Particular emphasis is put on elliptical copulas such as the normal and the t as these are flexible models in a multivariate setting. The implementation of the procedure for the latter copulas proves challenging and requires the extension of the Plackett formula for the t distribution to arbitrary dimension. Extensive Monte Carlo experiments, which could be carried out only because of the good computational properties of the multiplier approach, confirm in the multivariate multiparameter context the satisfactory behavior of the goodness-of-fit test.     

Minimizing the maximum travel time in a combined model of facility location and network design

This paper presents a combined Facility Location/Network Design Problem which simultaneously considers the location of facilities and the design of its underlying network so as to minimize the maximum customer-facility travel time. The model generalizes the classical p-center problem and has various applications in regional planning, distribution, telecommunications, emergency systems, and other areas. Two mixed integer programming formulations are presented and compared. Several valid inequalities are derived for the most promising of these formulations to strengthen its LP relaxation bound and to reduce the enumeration tree. Numerical results of a series of computational experiments for instances with up to 100 nodes and 500 candidate links are reported.     

Embedded paths and cycles in faulty hypercubes

An important task in the theory of hypercubes is to establish the maximum integer f _n such that for every set ℱ of f vertices in the hypercube Q_n,{\mathcal {Q}}_{n}, with 0≤f≤f _n , there exists a cycle of length at least 2 ⁿ −2f in the complement of ℱ. Until recently, exact values of f _n were known only for n≤4, and the best lower bound available for f _n with n≥5 was 2n−4. We prove that f ₅=8 and obtain the lower bound f _n ≥3n−7 for all n≥5. Our results and an example provided in the paper support the conjecture that f_n=((n) || 2)-2f_{n}={n\choose 2}-2 for each n≥4. New results regarding the existence of longest fault-free paths with prescribed ends are also proved.