Use of Biological Markers in Risk Assessment1

Measurements of intermediate end points in the carcinogenic process may reduce uncertainty in human risk assessment from bioassay data, by identifying sources of interspecies variation and dose nonlinearity. This paper describes desirable properties of such markers: persistence, predictive power, temporal relevance, and consistency across dose rate and species. We illustrate these properties by evaluating markers for squamous cell nasal carcinoma in rodents exposed to formaldehyde. We also discuss design issues for bioassays that evaluate markers and tumors simultaneously at necropsy.     

Emergency contraception: the politics of post-coital contraception

The literature and events related to the politicization of emergency contraceptive pills (ECPs) in the United States is reviewed. The basis of opposition to the regimen, rooted in the mode of action of ECPs, the confusion with mifepristone, and the challenges this presents for ECP advocates is also discussed. Legislative actions that impact the availability of ECPs are described, as well as efforts to increase access and availability through innovative programs, legislation, and changes in medical practice. Recommendations for future research, service delivery, and public policy are also presented .     

Exact Goodness‐of‐Fit Testing for the Ising Model

The Ising model is one of the simplest and most famous models of interacting systems. It was originally proposed to model ferromagnetic interactions in statistical physics and is now widely used to model spatial processes in many areas such as ecology, sociology, and genetics, usually without testing its goodness of fit. Here, we propose various test statistics and an exact goodness‐of‐fit test for the finite‐lattice Ising model. The theory of Markov bases has been developed in algebraic statistics for exact goodness‐of‐fit testing using a Monte Carlo approach. However, finding a Markov basis is often computationally intractable. Thus, we develop a Monte Carlo method for exact goodness‐of‐fit testing for the Ising model that avoids computing a Markov basis and also leads to a better connectivity of the Markov chain and hence to a faster convergence. We show how this method can be applied to analyze the spatial organization of receptors on the cell membrane.     

Modeling Cholinesterase Activity for Human Dietary Risk Assessment of Carbamate Insecticides

This article demonstrates statistical models to quantify the interaction between a carbamate insecticide and acetylcholinesterase. Carbamates are a class of chemicals that inhibit the activity of acetylcholinesterase in humans, an enzyme involved in the regulation of the neurotransmitter acetylcholine. Following exposure to a carbamate insecticide, we specifically address (1) if acetylcholinesterase activity recovers to its level of preexposure activity; (2) the level of inhibition of acetylcholinesterase activity; (3) the recovery time of acetylcholinesterase activity to its preexposure level for a typical individual; and (4) the upper percentiles of the recovery time of acetycholinesterase activity across individuals. A nonlinear mixed-effects model is fitted to data from a repeated measures experiment conducted with human volunteers randomly assigned to a control and four dose groups. Repeated measurements were taken prior to exposure and at 1, 2, 4, 6, 8, and 21 hours after exposure to the carbamate aldicarb. It was found that full recovery did occur. Inhibition at 1 hour was estimated with maximum inhibition most likely occurring prior to 1-hour postexposure. In addition, recovery was rapid even for sensitive individuals. Given this information, the potential effect from exposure to a carbamate consumed in the diet during a day can be quantitatively assessed.     

Parenting and Perceived Maternal Warmth in European American and African American Adolescents

Traditional conceptualizations of parenting style assume certain associations between parenting practices/philosophies and parental warmth. This study examines whether those links are similar for European American and African American adolescents. Two hundred and ninety‐eight early adolescents and their mothers reported on discipline and control practices, decision‐making practices, and parenting philosophy, which were used to predict adolescents’ reports of maternal warmth. The moderating role of ethnicity was examined after controlling for gender, age, and socioeconomic status. Although some practices predicted warmth similarly across groups, several practices predicted warmth in ways consistent with parenting style theory only or more strongly among European American adolescents. The findings suggest differences in the interpretation of or context surrounding discipline‐ and autonomy‐related practices in these groups.     

Relationship power,decision making,and sexual relations: An exploratory study with couples of Mexican origin

This study explored how couples of Mexican origin define power in intimate relationships, what makes men and women feel powerful in relationships, and the role of each partner in decision making about sexual and reproductive matters. Interviews were conducted with each partner of 39 sexually active couples and data were analyzed using content analysis. Results indicate that power is perceived as control over one's partner and the ability to make decisions. Women say they feel more powerful in relationships when they make unilateral decisions and have economic independence. Men feel powerful when they have control over their partner and bring home money. Respondents agreed that women make decisions about household matters and children, while men make decisions related to money. Findings indicate that whereas couples share decision making about sexual activities and contraceptive use, men are seen as initiators of sexual activity and women are more likely to suggest condom use.     

“You Never Know Who's Looking at Your Page!”: African American Male Adolescents’ Perceptions of Emotional Display Rules Online

Social network sites (SNSs) are a powerful new context for adolescent development. We qualitatively investigate African American adolescent boys’ (N = 50, mean age = 15.8) perceptions of emotional display rules on SNSs. We present and discuss a taxonomy of display rules for anger, sadness, embarrassment, and excitement. Perceived display rules around anger and sadness were most notable. Participants’ understandings of display rules around anger were complex and varied, with many describing threats of violence as marking the line between acceptable and unacceptable expressions. Although youth stated that expressing sadness via SNS could garner emotional support, this was understood somewhat consistently as unacceptable. Overall, our findings suggest that perceptions of emotional display rules on SNSs are varied, complicated, and can be difficult to navigate.     

A quadratic lower bound for Rocchio’s similarity-based relevance feedback algorithm with a fixed query updating factor

Rocchio’s similarity-based relevance feedback algorithm, one of the most important query reformation methods in information retrieval, is essentially an adaptive supervised learning algorithm from examples. In practice, Rocchio’s algorithm often uses a fixed query updating factor. When this is the case, we strengthen the linear Ω(n) lower bound obtained by Chen and Zhu (Inf. Retr. 5:61–86, 2002) and prove that Rocchio’s algorithm makes Ω(k(n−k)) mistakes in searching for a collection of documents represented by a monotone disjunction of k relevant features over the n-dimensional binary vector space {0,1} ⁿ , when the inner product similarity measure is used. A quadratic lower bound is obtained when k is linearly proportional to n. We also prove an O(k(n−k)³) upper bound for Rocchio’s algorithm with the inner product similarity measure in searching for such a collection of documents with a constant query updating factor and a zero classification threshold.     

Modelling state anxiety in a medical setting: The mediating role of embarrassment

Abstract

Little research has been conducted on the relationship between state anxiety and embarrassment in a medical setting. In the prcsent study, several personality and situational variables were examined as antecedents of state anxiety. A total of 277 patients who had come for an examination either as a response to a melanoma screening programme or due to a dermatological complaint participated in the study. Results showed that purpose of patient visit, physician's recommendation, trait anxiety, and embarrassment, were each correlated with state anxiety. Furthermore, using mediated regression analysis as well as structural equations, embarrassment was found to mediate between the above antecedents and state anxiety. The authors proposed a model linking all the variables and identifying their paths. Theoretical and practical considerations of the findings are discussed.