Comparison of the Stein and the usual estimators for the regression error variance under the Pitman nearness criterion when variables are omitted

This paper compares the Stein and the usual estimators of the error variance under the Pitman nearness (PN) criterion in a regression model which is mis-specified due to missing relevant explanatory variables. The exact expression of the PN-probability is derived and numerically evaluated. Contrary to the well-known result under mean squared errors (MSE), with the PN criterion the Stein variance estimator is uniformly dominated by the usual estimator when no relevant variables are excluded from the model. With an increased degree of model mis-specification, neither estimator strictly dominates the other. The authors are grateful to two anonymous referees for their valuable comments. Also, the first author is grateful to the Japan Society for the Promotion of Science for partial financial support.     

Online set multicover algorithms for dynamic D2D communications

Motivated by the dynamic resource allocation problem for device-to-device (D2D) communications, we study the online set multicover problem (OSMC). In the online set multicover, the set X of elements to be covered is unknown in advance; furthermore, the coverage requirement of each element \(x \in X\) is initially unknown. Elements of X together with coverage requirements are presented one at a time in an online fashion; and a feasible solution must be maintained at all times. We provide the first deterministic, online algorithms for OSMC with competitive ratios. We consider two versions of OSMC; in the first, each set may be picked only once, while the second version allows each set to be picked multiple times. For both versions, we present the first deterministic, online algorithms, with competitive ratios \(O( \log n \log m )\) and \(O( \log n (\log m + \log k) )\), repectively, where n is the number of elements, m is the number of sets, and k is the maximum coverage requirement. By simulation, we show the efficacy of these algorithms for resource allocation in the D2D setting by analyzing network throughput and other metrics, obtaining a large improvement in running time over offline methods.     

Reading Rites: Teaching Textwork in Graduate Education

The ability to comprehend, discuss, and use disciplinary texts is central to graduate education. Although techniques for teaching writing have been well-discussed, and even incorporated into graduate curricula, the same is not true for techniques of scholarly reading, a crucial skill that is largely untaught and which students must learn independently or through shared culture. We argue that more explicit training in reading has potential benefits for graduate student education. Drawing on thirty-six in-depth interviews with students in the social sciences, we focus on the routines of managing academic reading, necessary for accessing information for research. Graduate students develop techniques and schedules that permit them to read rapidly or carefully, to read for different academic purposes, and to make information retrievable through notating. We suggest how graduate programs might incorporate reading education into the curriculum.     

Eating together and eating alone: meal arrangements in British households

Sociology traditionally accounts for eating in terms of the social organization of meals, their provision and consumption. A recurrent public concern is that the meal is being subverted. This paper examines meal arrangements in British households in 2012, drawing on an online survey in the format of a food diary administered to 2784 members of a supermarket consumer panel. It charts the organization of contemporary eating occasions, paying attention to socio‐demographic variation in practice. Especially, it explores companionless meals, putting them in contexts of food provisioning and temporal rhythms. Findings show that eating alone is associated with simpler, quicker meals, and that it takes place most commonly in the morning and midday. Those living alone eat alone more often, but at similar meal times, and they take longer over their lone meals. Comparison with a similar study in 1955–6 suggests some fragmentation or relaxation in collective schedules. The implications are not straightforward, and the causes probably lie more in institutional shifts than personal preferences. Declining levels of commensality are, however, associated with a reduction in household size and, especially in households with children, difficulties of coordinating family members’ schedules.     

The affordable care act and long-term care: comprehensive reform or just tinkering around the edges?

The Patient Protection and Affordable Care Act (ACA) includes several provisions that aim to improve prevailing deficiencies in the nation's long-term care system. But just how effective is the ACA likely to be in addressing these challenges? Will it result in meaningful or marginal reform? This special issue of Journal of Aging & Social Policy seeks to answer these questions. The most prominent long-term care provision is the now-suspended Community Living Assistance Services and Supports Act. Others include incentives and options for expanding home- and community-based care, a number of research and demonstration projects in the areas of chronic care coordination and the dually eligible, and nursing home quality reforms. There are also elements that seek to improve workforce recruitment and retention, in addition to benefit improvements and spending reductions under Medicare. This article reviews the basic problems plaguing the long-term care sector and the provisions within the ACA meant to address them. It also includes a brief overview of issue content.     

A computerized system to monitor resilience indicators in organizations

The concepts developed by resilience engineering allow the understanding and monitoring the functioning of organizations and, particularly, to map the role of human activities, in success or in failure, enabling a better comprehension about how people make decisions in unexpected situations. The capture of information about human activities in the various organization levels gives managers a deeper real-time understanding of what is influencing the people performance, providing awareness of the factors that influence positively or negatively the organizational goals initially projected. The monitoring is important because the correct functioning of complex systems depends on the knowledge that people have to perform their activities and how the system environment provides tools that actually support the human performance. Therefore, organizations should look forward through precursors in operating signals to identify possible problems or solutions in the structure of tasks and activities, safety, quality, schedule, rework, and maintenance. We apply the concepts of resilience engineering to understand the organization by the analysis of cognitive tasks and activities. The aim is the development of a computerized system to monitor human activities to produce indicators to access system resilience. The validation of the approach was made in a real organization and the results show the successful applicability of the system. Based on findings obtained after the experiment of the system in a real organization, and managers and workers opinions, it was possible to show that the use of system provided an anticipated (real-time) perception about how activities are effectively being performed, allowing managers and workers to make decisions more consistent with daily problems, and also to anticipate solutions to cope with unexpected situations.     

Comparison of decapod communities across an urban-forest land use gradient in Puerto Rican streams

Urbanization influences a range of factors related to stream health, including the hydrologic regime, water quality, and riparian conditions that lead to negative effects on terrestrial and aquatic ecosystems. However, impacts on freshwater decapods from urbanization of tropical streams have not been reported. We hypothesized that changes in decapod communities in watersheds with different levels of urbanization are related to changes in physical stream habitats caused by different land uses and their effects on water discharge. The impacts of land use on the physico-chemical characteristics of streams and freshwater decapod communities were evaluated in three watersheds characterized by low, moderate and high-intensities of urbanization in Puerto Rico. For the low and moderately developed urban watersheds, decapod species richness ranged from 10 to 11 species; the highly urbanized watershed only had 4 species. Macrobrachium faustinum and Xiphocaris elongata were the most ubiquitously species and were found in all watersheds. Multivariable analysis of physical characteristics and densities of the decapod families resulted in one axis that explained 80 % of the total variation among the watersheds and was correlated with stream discharge. The effect of discharge is likely a result of frequent high flows that sustain habitats with high concentrations of dissolved oxygen and low concentrations of pollutants. An increase in physico-chemical parameters were observed from the LUW to the HUW. These results indicate that the decapod communities were most likely influenced by land use and environmental conditions that affected erosional aspects related to water discharge and water quality in the highly impacted watersheds.