Logistic Regression Models with Unspecified Low Dose–Response Relationships and Experimental Designs for Hormesis Studies

Hormesis refers to a nonmonotonic (biphasic) dose–response relationship in toxicology, environmental science, and related fields. In the presence of hormesis, a low dose of a toxic agent may have a lower risk than the risk at the control dose, and the risk may increase at high doses. When the sample size is small due to practical, logistic, and ethical considerations, a parametric model may provide an efficient approach to hypothesis testing at the cost of adopting a strong assumption, which is not guaranteed to be true. In this article, we first consider alternative parameterizations based on the traditional three‐parameter logistic regression. The new parameterizations attempt to provide robustness to model misspecification by allowing an unspecified dose–response relationship between the control dose and the first nonzero experimental dose. We then consider experimental designs including the uniform design (the same sample size per dose group) and the $c$‐optimal design (minimizing the standard error of an estimator for a parameter of interest). Our simulation studies showed that (1) the $c$‐optimal design under the traditional three‐parameter logistic regression does not help reducing an inflated Type I error rate due to model misspecification, (2) it is helpful under the new parameterization with three parameters (Type I error rate is close to a fixed significance level), and (3) the new parameterization with four parameters and the $c$‐optimal design does not reduce statistical power much while preserving the Type I error rate at a fixed significance level.     

Reducing litigation costs through better patient communication

The most common cause of malpractice suits is failed communication with the patients and their families. Explore ways that better communication could lead to fewer malpractice claims and allow health care organizations to reduce litigation costs.     

Sexual-moral attitudes, love styles, and mate selection

Students at a southwestern university were surveyed to test the interrelations of three constructs: sexual-moral attitudes, love styles, and attraction criteria. Following the procedures of the National Health and Social Life Survey, from which the sexual-moral attitude items were obtained, we conducted a cluster analysis to create attitudinal groupings. We obtained four clusters representing various nuances of liberalism and conservatism. When compared on love styles, the clusters differed primarily on ludus and pragma. Not only did some of the liberal clusters differ from some of the conservative ones on love styles, but there were also some differences within liberalism and within conservatism. Cluster differences also emerged on the attraction criteria.     

Housing problems experienced by recipients of child welfare services

This study uses data on the experiences of families involved with child welfare services to examine the nature of housing problems and needs among these families and whether housing status affects case outcomes. First, the article describes the housing difficulties faced by two distinct child welfare service populations: families receiving voluntary in-home services and families with children in court-ordered out-of-home care. Second, the study demonstrates the relationship between housing problems and the likelihood of family reunification for children in out-of-home care. The findings have implications for the delivery of child welfare services and the provision of housing assistance to low-income families with children.     

Bicycle ergometry in subacute-stroke survivors: feasibility, safety, and exercise performance

This study evaluated the feasibility, safety, and findings from a protocol for exercise-bicycle ergometry in subacute-stroke survivors. Of 117 eligible candidates, 14 could not perform the test and 3 discontinued because of cardiac safety criteria. In the 100 completed tests, peak heart rate was 116 +/- 19.1 beats/min; peak VO(2) was 11.4 +/- 3.7 ml x kg x min(-1), peak METs were 3.3 +/- 0.91, exercise duration was 5.1 +/- 2.84 min, and Borg score was 14 +/- 2.6. Among 71 tests, anaerobic threshold was achieved in 3.0 +/- 1.7 min with a VO(2) of 8.6 +/- 1.7 ml x kg x min(-1). After screening, this protocol is feasible and safe in subacute-stroke survivors with mild to moderate deficits. These stroke survivors have severely limited functional exercise capacity. Research and clinical practice in stroke rehabilitation should incorporate more comprehensive evaluation and treatment of endurance limitations.     

Teacher training in norm setting approaches to drug education: a pilot study comparing standard and video-enhanced methods

Norm setting has been shown to be a crucial element of effective drug education. The purpose of this study was to examine the degree to which a videotape describing concepts and methods for establishing positive norms would enhance standard training. Participants included 35 teachers and 64 health education students who were randomly assigned to the standard training condition or the video-enhanced training. Participants completed pretest and posttest measures of beliefs, attitudes, and knowledge concerning prevention methods. Both the standard and the video-based instruction produced improved understanding of norms and norm setting prevention methods. However, the video-based instruction resulted in several notable improvements beyond what was achieved in standard instruction. Video training can be an important tool as research-based drug abuse prevention achieves wide-scale dissemination. It offers a way of standardizing training and has the potential to increase the fidelity with which prevention programs are implemented.     

Impact of Microbial Ecology of Meat and Poultry Products on Predictions from Exposure Assessment Scenarios for Refrigerated Storage

A novel extension of traditional growth models for exposure assessment of food-borne microbial pathogens was developed to address the complex interactions of competing microbial populations in foods. Scenarios were designed for baseline refrigeration and mild abuse of servings of chicken broiler and ground beef Our approach employed high-quality data for microbiology of foods at production, refrigerated storage temperatures, and growth kinetics of microbial populations in culture media. Simple parallel models were developed for exponential growth of multiple pathogens and the abundant and ubiquitous nonpathogenic indigenous microbiota. Monte Carlo simulations were run for unconstrained growth and growth with the density-dependent constraint based on the "Jameson effect," inhibition of pathogen growth when the indigenous microbiota reached 10(9) counts per serving. The modes for unconstrained growth of the indigenous microbiota were 10(8), 10(10), and 10(11) counts per serving for chicken broilers, and 10(7), 10(9) and 10(11) counts per serving for ground beef at respective sites for backroom, meat case, and home refrigeration. Contamination rates and likelihoods of reaching temperatures supporting growth of the pathogens in the baseline refrigeration scenario were rare events. The unconstrained exponential growth models appeared to overestimate L. monocytogenes growth maxima for the baseline refrigeration scenario by 1500-7233% (10(6)-10(7) counts/serving) when the inhibitory effects of the indigenous microbiota are ignored. The extreme tails of the distributions for the constrained models appeared to overestimate growth maxima 110% (10(4)-10(5) counts/serving) for Salmonella spp. and 108% (6 x 10(3) counts/serving) for E. coli O157:H7 relative to the extremes of the unconstrained models. The approach of incorporating parallel models for pathogens and the indigenous microbiota into exposure assessment modeling motivates the design of validation studies to test the modeling assumptions, consistent with the analytical-deliberative process of risk analysis.     

A Community Response to Tragedy: Individualized Services for Families

The murder of a 13-year-old young woman mobilized one community to initiate a wraparound service model for their most hard-to-reach families. These families struggled with parental substance abuse, youth at high risk, and associated complex needs cutting across existing categorical programs. The strength and empowerment based program, in which interventions were designed specific to each family, presented challenges in evaluating outcomes with traditional standardized instruments. This paper describes the project, its outcomes for families and youth, and the evaluation design that evolved to measure outcomes in a strength-based program with no uniform intervention.     

Yes-no voting

Yes-No (Y-N) voting is a voting method for choosing a governing coalition in a parliament after the seating of its members. Each member can designate a party to be Y (it must be included in the governing coalition), N (it must be excluded from the governing coalition), or neither (it may be either in or out of the governing coalition). The majority coalition acceptable to the most voters, because it includes all parties that these voters designate Y and no parties that they designate N, is given the first opportunity to form a government. Possible combinations of majority coalitions that a member might vote for are derived, including ones based on consistent and interval voting strategies. Examples illustrate a number of different phenomena, such as when a rational voter might not be loyal to his or her party by designating it Y.