Finding optimal three-dimensional molecular configurations based on a limited amount of experimental and/or theoretical data requires efficient nonlinear optimization algorithms. Optimization methods must be able to find atomic configurations that are close to the absolute, or global, minimum error and also satisfy known physical constraints such as minimum separation distances between atoms (based on van der Waals interactions). The most difficult obstacles in these types of problems are that 1) using a limited amount of input data leads to many possible local optima and 2) introducing physical constraints, such as minimum separation distances, helps to limit the search space but often makes convergence to a global minimum more difficult. We introduce a constrained global optimization algorithm that is robust and efficient in yielding near-optimal three-dimensional configurations that are guaranteed to satisfy known separation constraints. The algorithm uses an atom-based approach that reduces the dimensionality and allows for tractable enforcement of constraints while maintaining good global convergence properties. We evaluate the new optimization algorithm using synthetic data from the yeast phenylalanine tRNA and several proteins, all with known crystal structure taken from the Protein Data Bank. We compare the results to commonly applied optimization methods, such as distance geometry, simulated annealing, continuation, and smoothing. We show that compared to other optimization approaches, our algorithm is able combine sparse input data with physical constraints in an efficient manner to yield structures with lower root mean squared deviation.

How successful are HIV prevention programs? Which HIV prevention programs are most cost effective? Which programs are worth expanding and which should be abandoned altogether? This book addresses the quantitative evaluation of HIV prevention programs, assessing for the first time several different quantitative methods of evaluation.

The authors of the book include behavioral scientists, biologists, economists, epidemiologists, health service researchers, operations researchers, policy makers, and statisticians. They present a wide variety of perspectives on the subject, including an overview of HIV prevention programs in developing countries, economic analyses that address questions of cost effectiveness and resource allocation, case studies such as Israel's ban on Ethiopian blood donors, and descriptions of new methodologies and problems.

A best seller in its first edition, Institutions and Organizations has been thoroughly revised and expanded. This second edition provides a comprehensive overview of the institutionalist approach to organization theory. Dick Scott presents a historical overview of the theoretical literature, an integrative analysis of current institutional approaches, and a review of empirical research related to institutions and organizations. He offers an extensive review and critique of institutional analysis in sociology, political science, and economics as it relates to recent theory and research on organizations.

The second edition gives particular attention to the topics of agency and structure and to institutional change. Given the constraining and constitutive properties of institutions, how can actors intervene to introduce novelty? How is change possible? To a previous concern with "convergent" change, a focus on increasing structural isomorphism, the author adds a thorough analysis of the sources of "disruptive" change, deinstitutionalization, and the emergence of new kinds of institutions.

First edition 1995; Selected as one of the Outstanding Academic Books of 1995 by Choice.

Many health plans apply evidence-based approaches to coverage decisions. The foundation of such approaches is the systematic review of information about the effectiveness of medical interventions. This paper discusses the principles underlying evidence-based coverage policy and how they are applied by two major programs: the Technology Evaluation Center of the Blue Cross Blue Shield Association and the Medicare Coverage Advisory Committee. Although such policies likely have limited effects on spending, they can help to direct medical resources toward effective care.

In response to a mail survey, 225 leading general internists provided their opinions of the relative importance to patients of thirty medical innovations. They also provided information about themselves and their practices. Their responses yielded a mean score and a variability score for each innovation. Mean scores were significantly higher for innovations in procedures than in medications and for innovations to treat cardiovascular disease than for those to treat other diseases. The rankings were similar across subgroups of respondents, but the evaluations of a few innovations were significantly related to physicians' age. The greatest variability in response was usually related to the physician's patient mix.

The specter of multidrug-resistant tuberculosis (MDR-TB) threatens the gains achieved by tuberculosis control through international recommendations currently accepted by 127 countries. The high cost of second-line drugs is a clear example of a market failure serving as a barrier to treatment of MDR-TB cases. Gupta et al. describe an approach based on policy development, consolidating and increasing demand, and increasing supply to decrease the cost of second-line drugs. As a result, prices decreased from 48-97% for a treatment regimen and competition was increased in monopoly markets. An independent scientific committee fosters access to the drugs under tightly monitored pilot projects to prevent the creation of resistance to second-line drugs. This strategy may be applicable to other infectious-disease treatment efforts.