Experimental design for response surface gradient estimation

In this paper, a new experimental design and gradient estimation procedure is presented for Phase I response surface optimization. The design is motivated by basic principles of differential calculus, which imply that if a point in Rⁿ has been reached by exactly minimizing a function along a given direction, then the gradient of the function at that point must be orthogonal to the search direction followed. While exact line search is not required for the new design to be effective, this principle implies that the dimension of the gradient estimation procedure may often be reduced from n to n-1 variables, and the experimenter is able to concentrate experimental effort within the most productive region around the center of the design. The new design and gradient estimation procedures are presented, and bias and variance properties are derived. The effectiveness of the new design is shown to depend on the experimenter's ability to terminate line search within a near-stationary region of the line search function A simple heuristic is presented which indicates whether the new design should be used at a given experimental region.     

Metabolic Syndrome,Obesity, and Related Risk Factors Among College Men and Women

Abstract

Objectives: The primary objective of this study was to characterize the prevalence of overweight/obesity, metabolic syndrome (MbS) and its criteria, and nutrient intakes of college-age men and women via a large-scale screening. Participants and Methods: From August 2005 to July 2008, 2,722 subjects were recruited for the ongoing, cross-sectional Young Adult Health Risk Screening Initiative project. Anthropometric, biochemical, clinical, and dietary data were collected. Results: Approximately one-half of men and more than one-quarter of women were overweight or obese. MbS was identified in 9.9% of men and 3.0% of women; 77% of men and 54% of women had at least 1 MbS criterion. Intakes of saturated fat, magnesium, and fiber, as well as body mass index and reported physical activity levels were related to MbS. Conclusions: Because of high rates of overweight/obesity and MbS, college-age adults are at risk for developing chronic diseases including diabetes mellitus and cardiovascular disease     

Innovation in education: Technological economics

Technological change and innovation are vital parts of the economy. This paper concerns one particular attempt to study both the process of innovation itself and possible means of increasing its effectiveness: Technological Economics. Barriers to innovation, intellectual and organizational, are described from the experience at the University of Stirling.     

Tipping the Multiracial Color-Line: Racialized Preferences of Multiracial Online Daters

Building on previous work on US multiraciality, we analyze the messaging patterns of Asian-white, Hispanic-white, and black-white multiracial heterosexual     

Retaining clients in an outcome monitoring evaluation study: HIV prevention efforts in community settings

The Centers for Disease Control and Prevention (CDC), Division of HIV/AIDS Prevention (DHAP) conducted outcome monitoring studies on evidence-based interventions (EBIs) provided by CDC-funded community-based organizations (CBOs). Critical to the success of outcome monitoring was the ability of CBOs to recruit and retain clients in evaluation studies. Two EBIs, Video Opportunities for Innovative Condom Education and Safer Sex (VOICES/VOCES) and Healthy Relationships, were evaluated using repeated measure studies, which require robust follow-up retention rates to increase the validity and usefulness of the findings. The retention rates were high for both VOICES/VOCES CBOs (95.8% at 30 days and 91.1% at 120 days), and Healthy Relationships CBOs (89.5% at 90 days and 83.5% at 180 days). This paper presents an overview of the retention of clients, challenges to follow-up, and strategies developed by CBOs to achieve high retention rates. These strategies and rates are discussed within the context of the CBOs’ target populations and communities.     

External costs: Myth or rationale for state intervention?

The paper considers the extent to which problems of environmental pollution can be left to the market system. The concept of external cost is used to establish the presumption that market forces will lead to excessive pollution. The performance criterion, that of Pareto efficiency, leading to this presumption is discussed. It is shown that for significant problems of pollution it is not possible to limit the role of the state to that of re-defining property rights. What is necessary is state intervention by way of the taxing, or regulation, of discharges into the environment: where external effects are undepletable, markets cannot meet the requirements of Pareto efficiency. Government intervention to meet such requirements requires that the government has information which is, in practice, either unavailable or very costly. Intervention towards more restricted goals is discussed. It is shown that arguments to the effect that the role of the state can be restricted to defining private property rights are based on assumptions which are irrelevant to significant problems. In particular, it is argued that a recent publication by the Institute of Economic Affairs does not, as claimed, show either that external costs do not exist, or that they exist but imply a minor role for the state in the protection of the natural environment.