Spatial prediction of crystalline defects observed in molecular dynamic simulations of plastic damage

Molecular dynamic computer simulation is an essential tool in materials science to study atomic properties of materials in extreme environments and guide development of new materials. We propose a statistical analysis to emulate simulation output with the ultimate goal of efficiently approximating the computationally intensive simulation. We compare several spatial regression approaches including conditional autoregression (CAR), discrete wavelets transform (DWT), and principle components analysis (PCA). The methods are applied to simulation of copper atoms with twin wall and dislocation loop defects, under varying tilt tension angles. We find that CAR and DWT yield accurate results but fail to capture extreme defects, yet PCA better captures defect structure.     

Distinctive features of age-specific fertility profiles in the English-speaking world: common patterns in Australia,Canada, New Zealand and the United States, 1970-98

The paper seeks to identify common features in the fertility patterns of the English-speaking world and provide a model basis for comparison of fertility between countries and over time. Attention is focused on the heterogeneity within the fertility patterns of Australia, Canada, New Zealand, and the United States, similar to that reported earlier for the UK and the Irish Republic. The recent age-specific fertility patterns of these countries display a marked 'bulge' in fertility of women under age 25. A mixture model with two-component Hadwiger functions provides a suitable fit. The heterogeneity thus suggested is related to the proportion of births outside marriage. Additionally, there is some evidence that, in the United States, and lesser extent in New Zealand, this heterogeneity in fertility patterns may be explained by ethnic difference in the timing and number of births.     

A special section for correspondence and controversy

This paper gives crude estimates of the environmental consequences associated with the birth of one baby in the United States. We calculate the magnitude of one hundred environmental impacts which one American born today will cause over a lifetime. The impacts are grouped under five headings: waste generation, mineral consumption, energy consumption, ecosystem alteration, and food consumption. We also consider, but do not quantify, impacts on extinctions of species and indigenous cultures. Our purpose is to emphasize the role of population growth in the creation of environmental problems, and to make potential parents aware of their ability to impact the global environment. We conclude that one especially effective way for individuals to protect the national and global environment, and hence protect the wellbeing of all existing people, is to stop creating more humans.     

Social-ecological science in the humane metropolis

The Humane metropolis is a rubric to summarize and promote environmental and social quality in contemporary urban mosaics. Because cities, suburbs, and exurbs, as spatially extensive and connected socio-ecological systems, exhibit many negative features, the humane metropolis identifies a strategy to combat the ills and instill more positive and sustainable features and processes in urban systems. Because the humane metropolis as a program has arisen primarily from social motivations, there is the opportunity to articulate more explicitly the role that science can play in addressing the humane metropolis program and evaluating its success. A humane metropolis can be summarized as one that 1) protects and restores ecological services in cities and suburbs, 2) promotes physical and mental health and safety of residents, 3) enhances efficiency by conserving energy, matter, water, and time, 4) facilitates equity by being inclusive, as well as socially and environmentally just, and 5) maintains a sense of community and a sense of place. We clarify the nature of science as a contributor to the social program, pointing out the social values motivating science, and the role that scientific knowledge and metaphor play in linking science with the social program of the humane metropolis. We further identify roles that socio-ecological research can play in meeting the goals of the humane metropolis. We use examples of environmental history, watershed function and restoration, and environmental justice research and action from the Baltimore Ecosystem Study, Long-Term Ecological Research program. The humane metropolis as a social program benefits from scientific contributions that 1) expose hidden ecological processes in urban systems, 2) generate knowledge connecting people and institutions to the biophysical environment, 3) contribute to the civic dialog, and 4) bring scientific values to the prioritization and balancing of the goals of the humane metropolis.     

Unsold Versus Unbought Commitment: Minimum Total Commitment Contracts with Nonzero Setup Costs

We study a minimum total commitment (MTC) contract embedded in a finite‐horizon periodic‐review inventory system. Under this contract, the buyer commits to purchase a minimum quantity of a single product from the supplier over the entire planning horizon. We consider nonstationary demand and per‐unit cost, discount factor, and nonzero setup cost. Because the formulations used in existing literature are unable to handle our setting, we develop a new formulation based on a state transformation technique using unsold commitment instead of unbought commitment as state variable. We first revisit the zero setup cost case and show that the optimal ordering policy is an unsold‐commitment‐dependent base‐stock policy. We also provide a simpler proof of the optimality of the dual base‐stock policy. We then study the nonzero setup cost case and prove a new result, that the optimal solution is an unsold‐commitment‐dependent (s, S) policy. We further propose two heuristic policies, which numerical tests show to perform very well. We also discuss two extensions to show the generality of our method's effectiveness. Finally, we use our results to examine the effect of different contract terms such as duration, lead time, and commitment on buyer's cost. We also compare total supply chain profits under periodic commitment, MTC, and no commitment.     

Inequities in Higher Education: Issues and Promising Practices in a World Ambivalent about Affirmative Action

The U.S. Supreme Court ruled on the legality of race-based affirmative action at universities in 2003. Although the decisions affirmed the legality of considering race in college admissions decisions, their long-term effects are not entirely clear. They neither resolved conflicts nor solved problems affirmative action was intended to address, namely, disparities in educational outcomes between Whites and ethnic/racial minorities. Although disparities have diminished since 1965, policies and practices to sustain and further increase diversity in higher education without affirmative action are needed. This article provides historical and conceptual grounding for this JSI issue, which examines approaches for attaining campus diversity. Collectively, the issue provides approaches for increasing diversity as well as strategies for managing and benefiting from diversity in postsecondary environments.     

Media Coverage of Hazard Events: Analyzing the Assumptions*

Despite the widespread conviction that the mass media tend to “blow risks out of proportion,” the question has received little systematic attention. The mass-media literature also presents the opposite argument, namely that the media minimize the kinds of reporting that might upset large-scale capitalistic industries. Still other perspectives hold, on the one hand, that media reports tend to have more subtle anti-technology effects, created by “even-handed” coverage and on the other hand, that reporters give “establishment” figures the opportunity to “keynote” or “put the facts in perspective” in ways that exert a subtly pro-technology effect. Drawing on a systematic sample of 128 hazard events developed by researchers at another university and factually summarized by Lexis -Nexis , we analyze the effects of emotionalism on actual levels of coverage; a variety of analyses show that the only variables to exert significant effects are those that involve objective information, such as the number of casualties or the level of damage created. Given the argument that the effects of emotionalism can be conveyed in ways that are largely independent of the facts, e.g., by headlines, photographs, and “loaded” words, we next compare the emotionalism conveyed by factual summaries vs. the original stories and headlines. Even for incidents involving nuclear and/or toxic hazards, we find the net effect of the full stories is to lessen the emotionalism. Overall, the hypothesis receiving strongest support is that the “keynoting” helps create an overall impression that the “responsible authorities” are acting more responsibly than might be assumed on the basis of factual summaries alone. The widespread impression within the technical community, while understandable, may well have as much to do with the selective perceptions of scientists and engineers as with the actual pattern of media reporting.     

Social change in outer city British public housing

This paper offers a detailed examination of the evolution of social patterns within a representative outer council estate in Birmingham, England during 1971–1981. The findings disclose several important changes including a growing association of flatted accommodation with smaller childless households and increasing social deprivation on the whole estate.