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.     

Purchase deadline as a moderator of the effects of price uncertainty on search duration

A longstanding theoretical tenet in the economic psychology literature is that consumers respond to greater price uncertainty by increasing search. The generality of this tenet was investigated in the context of a moderating variable, purchase deadline. It was hypothesized that the effect of increased price uncertainty, as reflected by both cross-sectional price variability and longitudinal price variability, was moderated by temporal proximity to a purchase deadline. The hypothesis was tested by analyzing purchase data from a sample of consumers with known purchase deadlines searching for rental trucks. The results indicated that search increased in response to greater price uncertainty for distant deadlines but decreased in response to greater price uncertainty for proximal deadlines.     

Social cognitive neuroscience and leadership

We provide an overview of how the emerging field of social cognitive neuroscience can be linked to leadership theory and practice. A number of challenges are addressed, including theory development, as well as technical, measurement and methodological issues. In addition, we review recent leadership research that involves neuroscience applications, as well as areas that are closely related to leadership, such as emotional regulation and ethical reasoning and decision-making. Consideration is also given to how neuroscience might inform leadership development processes. We conclude with a discussion of the institutional challenges in conducting leadership research that incorporates neuroscience, and we consider potential limitations of such applications.     

Behavioral Language Interventions for Children with Autism: Comparing Applied Verbal Behavior and Naturalistic Teaching Approaches

The Analysis of Verbal Behavior - Several important behavioral intervention models have been developed for teaching language to children with autism and two are compared in this paper....     

Adolescents with learning disabilities who show sexually inappropriate or abusive behaviours: development of a research study

This paper sets out some key issues regarding sexual abuse perpetrated by adolescents with a learning disability. The limited evidence currently available is largely anecdotal or from small‐scale/case studies, but emphasizes that much behaviour of this kind never comes to the attention of either statutory social services or the criminal justice system. It is argued here that statutory services should be involved in such cases in order both to protect potential victims and to improve the ongoing life chances of alleged perpetrators. Speci?cally, it is posited that only by naming this problem can professionals hope to make effective interventions. The various organizational structures and systems adopted by four social services departments are outlined and their possible impacts on case outcomes are discussed. Little empirical research has so far been undertaken in this highly sensitive area, but an initiative from The Ann Craft Trust (formerly NAPSAC) aims to provide new evidence to help shape future best practice in this ?eld. Copyright © 2003 John Wiley & Sons, Ltd.     

Genetically Engineered Plants, Endangered Species, and Risk: A Temporal and Spatial Exposure Assessment for Karner Blue Butterfly Larvae and Bt Maize Pollen

Genetically engineered maize (Zea mays) containing insecticidal endotoxin proteins from Bacillus thuringiensis (Bt) delta-endotoxin proteins has been adopted widely in the Midwestern United States. The proteins are toxic to several lepidopteran species and because a variety of maize tissues, including pollen, may express the endotoxins, the probability of exposure to nontarget species, including endangered species, needs to be understood. The objective of this study was to assess the potential temporal and spatial exposure of endangered Karner blue butterfly larvae (Lycaeides melissa samuelis) to Bt maize pollen in Wisconsin using probabilistic exposure techniques and geographic information systems analysis. Based on degree-day modeling of butterfly phenology and maize pollen shed, there is some potential for temporal exposure of larvae to maize pollen. However, in the majority of years and locations, maize pollen shed most likely will occur after the majority of larval feeding on wild lupine (Lupinus perennis). The spatial analysis indicates that some Karner blue butterfly populations occur in close proximity to maize fields, but in the vast majority of cases the butterfly's host plant and maize fields are separated by more than 500 m. A small number of potential or existing Karner blue butterfly sites are located near maize fields, including sites in two of the four counties where temporal overlap is most likely. The exposure assessment indicates that these two counties should receive the highest priority to determine if Karner blue butterfly larvae are actually at risk and then, if needed, to reduce or prevent exposure.     

Chemical and biological agent incident response and decision process for civilian and public sector facilities.

In the event of a terrorist attack or catastrophic release involving potential chemical and/or biological warfare agents, decisionmakers will need to make timely and informed choices about whether, or how, to respond. The objective of this article is to provide a decision framework to specify initial and follow-up actions, including possible decontamination, and to address long-term health and environmental issues. This decision framework consists of four phases, beginning with the identification of an incident and ending with verification that cleanup and remediation criteria have been met. The flowchart takes into account both differences and similarities among potential agents or toxins at key points in the decision-making process. Risk evaluation and communication of information to the public must be done throughout the process to ensure a successful effort.     

A Multistate model of fecundability and sterility

This paper develops a multistate hazards model for estimating fecundability and sterility from data on waiting times to conception. Important features of the model include separate sterile and nonsterile states, a distinction between preexisting sterility and sterility that begins after initiation of exposure, and log-normally distributed fecundability among nonsterile couples. Application of the model to data on first birth intervals from Taiwan, Sri Lanka, and the Amish shows that heterogeneity in fecundability is statistically significant at most ages, but that preexisting sterility and new sterility are unimportant before age 40. These results suggest that sterility may not be an important determinant of natural fertility until later reproductive ages.     

Homeless youths' perceptions of services and transitions to stable housing

Use of available services is low among homeless youths, and how youth make decisions to access services or seek housing is unclear. This study explored perspectives of current and former street youth about these processes. Recruited from the streets and a drop-in center, 27 youth ages 16–24, participated in individual qualitative interviews. Findings from consensual qualitative analyses indicated choices to use services were embedded within developing autonomy and identification with street lifestyles. Themes of self-reliance, substance use, and relationships with street and housed persons were expressed as critical for both using services and transitioning to stable housing. Agency-related factors such as caring staff, a nonjudgmental atmosphere, and flexible policies were perceived as important for service use while youth-related factors such as experiencing major events, being internally motivated, and embracing mainstream values were seen as conducive to transitioning off the streets. Implications for service providers and future research are discussed.