A new heteroscedastic regression to analyze mass loss of wood in civil construction in Brazil

A heteroscedastic regression based on the odd log-logistic Marshall–Olkin normal (OLLMON) distribution is defined by extending previous models. Some structural properties of this distribution are presented. The estimation of the parameters is addressed by maximum likelihood. For different parameter settings, sample sizes and some scenarios, various simulations investigate the performance of the heteroscedastic OLLMON regression. We use residual analysis to detect influential observations and to check the model assumptions. The new regression explains the mass loss of different wood species in civil construction in Brazil.     

Physician career management: organizational strategies for the 21st century.

Burnout is a state of physical, emotional, and mental exhaustion caused by long-term involvement in situations that are emotionally demanding. It is not stress, per se, that causes burnout, as many thrive in stressful, demanding careers. Rather, burnout results when stress continuously outweighs the sense of effectiveness, accomplishment, and reward. And, this fate is sealed when one feels helpless to effect significant change in the conditions that fuel the stress. Establishing an organizational environment that reduces the risk of physician burnout requires a new commitment of resources, one that can be challenging to justify to decision-makers with a strictly short-term, bottom line orientation. The key issues to consider in shaping a physician career management program include: (1) entry of new physician employees into the organization; (2) productivity measures; (3) responsiveness to safety concerns; (4) administrative and policy issues; and (5) variety and growth opportunities.     

On the number of separable partitions

Consider partitions of a given set A of n distinct points in general position in ℝ ^d into parts where each pair of parts can be separated by a hyperplane that contains a given set of points E. We consider the problem of counting and generating all such partitions (correcting a classic 1967 result of Harding about the number of such partitions into two parts). Applications of the result to partition problems are presented.     

“How Exposed Is Exposed Enough?” Lay Inferences About Chemical Exposure

The concept of exposure is central to chemical risk assessment and plays an important role in communicating to the public about the potential health risks of chemicals. Research on chemical risk perception has found some indication that the model lay people use to judge chemical exposure differs from that of toxicologists, thereby leading to different conclusions about chemical safety. This paper presents the results of a series of studies directed toward developing a model for understanding how lay people interpret the concept of chemical exposure. The results indicate that people's beliefs about chemical exposure (and its risks) are based on two broad categories of inferences. One category of inferences relates to the nature in which contact with a chemical has taken place, including the amount of a chemical involved and its potential health consequences. A second category of inferences about chemical exposure relates to the pragmatics of language interpretation, leading to beliefs about the motives and purposes behind chemical risk communication. Risk communicators are encouraged to consider how alternative models of exposure and language interpretation can lead to conflicting conclusions on the part of the public about chemical safety.     

Choices at various levels of uncertainty: An experimental test of the restated diversification theorem

Our “Restated diversification theorem” (Skogh and Wu, 2005) says that risk-averse agents may pool risks efficiently without assignment of subjective probabilities to outcomes, also at genuine uncertainty. It suffices that the agents presume that they face equal risks. Here, the theorem is tested in an experiment where the probability of loss, and the information about this probability, varies. The result supports our theorem. Moreover, it tentatively supports an evolutionary theory of the insurance industry—starting with mutual pooling at uncertainty, turning into insurance priced ex ante when actuarial information is available.     

Exercising Property Rights to Pollute: Do Cancer Risks and Politics Affect Plant Emission Reductions?

This paper examines whether firms' decisions about reductions in toxic emissions depend on the magnitude of dangers arising from their pollution and on who bears pollutant risks. Controlling for the quantity of air toxics released in 1988, this article finds that plants whose emissions generated higher numbers of expected cancer cases did reduce their emissions more between 1988 and 1991. The nature of the community bearing the pollution risk also affected firm decisions. The higher the voter turnout in the area, a proxy for residents' likelihood of collective action, the greater the reductions in a plant's release of air carcinogens.