Membranes, mitochondria and amoebae: shape models

Most real-world shapes and images are characterized by high variability- they are not rigid, like crystals, for example—but they are strongly structured. Therefore, a fundamental task in the understanding and analysis of such image ensembles is the construction of models that incorporate both variability and structure in a mathematically precise way. The global shape models introduced in Grenander's general pattern theory are intended to do this. In this paper, we describe the representation of two-dimensional mitochondria and membranes in electron microscope photographs, and three-dimensional amoebae in optical sectioning microscopy. There are three kinds of variability to all of these patterns, which these representations accommodate. The first is the variability in shape and viewing orientation. For this, the typical structure is represented via linear, circular and spherical templates, with the variability accomodated via the application of transformations applied to the templates. The transformations form groups: scale, rotation and translation. They are locally applied throughout the continuum and of high dimension. The second is the textural variability; the inside and outside of these basic shapes are subject to random variation, as well as sensor noise. For this, statistical sensor models and Markov random field texture models are used to connect the constituent structures of the shapes to the measured data. The third variability type is associated with the fact that each scene is made up of a variable number of shapes; this number is not assumed to be known a priori. Each scene has a variable number of parameters encoding the transformations of the templates appropriate for that scene. For this, a single posterior distribution is defined over the countable union of spaces representing models of varying numbers of shapes. Bayesian inference is performed via computation of the conditional expectation of the parametrically defined shapes under the posterior. These conditional mean estimates are generated using jump-diffusion processes. Results for membranes, mitochondria and amoebae are shown.     

Sources of drug information among adolescent students

A sample of 1023 eighth and tenth grade students in small to medium-sized central Texas school districts was assessed to determine the amount of information they receive from ten sources about six categories of drugs. The amount of information males reported receiving about each drug category was significantly greater than what females reported, and the amount of information that eighth graders reported receiving about each drug category was significantly greater than what tenth graders reported. Television was the primary source of drug information for all categories of drugs except inhalants, for which friends and television were equally important sources. Parents and printed media (magazines or newspapers) were of secondary importance, followed by friends and teachers. Adolescents were less likely to receive drug-related information from experience, siblings, church, doctors, and police. The reliance on the mass media for drug information in smaller school districts is a pattern which has been previously observed in larger urban districts. This consistency suggests that mass media approaches to drug education are likely to be as effective in rural areas and smaller towns as they are among urban adolescents. Implications for television programming are discussed.     

The Influence of the Socio-economic Characteristics of Disabled People on Their Employment Status and Income

Most of the studies of the employment and income levels of disabled people focus on a specific disability or on severely disabled persons. A few studies are cross disability ones, but they fail to go beyond simple associations or else have extremely small sample sizes. There is a need for studies which are cross disability and which have an adequate sample size in order to determine if there are structural variables in society—like a class system-which operate upon the employment opportunities of disabled persons. Using a sample (n = 733) of the Disability Community in Massachusetts, socio-economic variables related to employment and income are studied. Statistically significant relationships are found. Several models are developed and the implications for social theory are discussed.     

Naming Men as Men: Implications for Work,Organization and Management

This paper seeks to contribute to the growing interest in naming men as men as part of a critical analysis of gendered power relations in organizations. The paper highlights the way in which men and masculinities are frequently central to organizational analysis, yet rarely the focus of interrogation. They remain taken for granted and hidden. Examining recent studies that contribute to a critical analysis of gendered power relations, we consider the growing interest in multiplicity, diversity and difference. In particular, we explore the issue of ‘multiple masculinities’ as well as some of the conceptual difficulties that surround it. Arguing for an approach which addresses the unities, differences and interrelations between men and masculinities, we suggest that critical studies of gendered power need to examine the management of organizations in much more detail. Highlighting five masculinities that seem to be routinely embedded in managerial discourses and practices, we conclude by advocating further research in this previously neglected area.     

TEACHING TOOLS: ECONOMICS OF CHILDHOOD IMMUNIZATION

Recent outbreaks of measles and other childhood diseases have put immunization policy on the national agenda. This teaching note on childhood immunization, intended for principles courses, discusses the rationale for government involvement, the situation in the U.S., and the policies of Northern Ireland and Austria. It emphasizes (a) the use of financial incentives to motivate behavior, (b) the distinction between shifting and moving along the demand curve, and (c) the notion of negative prices (i.e., paying the customer to "buy" the item). Students especially like the idea of the demand curve extending below the x-axis.     

Adaptive Management: A Paradigm for Remediation of Public Facilities Following a Terrorist Attack

Terrorist actions are aimed at maximizing harm (health, psychological, economical, and political) through the combined physical impacts of the act and fear. Immediate and effective response to a terrorist act is critical to limit human and environmental harm, effectively restore facility function, and maintain public confidence. Though there have been terrorist attacks in public facilities that we have learned from, overall our experiences in restoration of public facilities following a terrorist attack are limited. Restoration of public facilities following a release of a hazardous material is inherently far more complex than in industrial settings and has many unique technical, economic, social, and political challenges. For example, there may be a great need to quickly restore the facility to full operation and allow public access even though it was not designed for easy or rapid restoration, and critical information is needed for quantitative risk assessment and effective restoration must be anticipated to be incomplete and uncertain. Whereas present planning documents have substantial linearity in their organization, the “adaptive management” paradigm provides a constructive parallel paradigm for restoration of public facilities that anticipates and plans for uncertainty, inefficiencies, and stakeholder participation. Adaptive management grew out of the need to manage and restore natural resources in highly complex and changing environments with limited knowledge about causal relationships and responses to restoration actions. Similarities between natural resource management and restoration of a public facility after a terrorist attack suggest that integration of adaptive management principles explicitly into restoration processes will result in substantially enhanced and flexible responses necessary to meet the uncertainties of potential terrorist attacks.