Ban Estimation for Chi-Square Test Criteria in Categorical Data

This expository paper describes some recent work that further develops the theory of BAN estimators and the related chi-scuare test statistics.The extensions are in several directions: (a) the class of regular estimators is broadened by permitting extraneous random elements; (b) more general models are permitted under the constraint equations specification; and (c) BAN estimators are defined for general models combining features of two types of specification.In particular, WLS estimators are shown to be BAN.     

Why Wait ‘til Marriage? The Determinants of Premarital Sex among Adolescents in a Country in Sub-Saharan Africa: Botswana

The purpose of the study was to describe the premarital sexual behaviors of Botswana adolescents and examine the factors associated with premarital sex intentions. An anonymous self-reported questionnaire was administered to 1,054 pupils ages 10 to 18 years in school and out of school. The findings indicate that the theory of planned behavior provides a model for developing interventions to reduce the risk behavior in regard to HIV/AIDS through premarital sex. The findings in the study indicate factors that influence adolescent intentions to engage in premarital sexual intercourse and the need to address these when designing effective interventions.     

Why can patients with erectile dysfunction be considered lucky? The association with testosterone deficiency and metabolic syndrome

Metabolic syndrome (MetS) is a diagnostic category, based on a cluster of risk factors (hyperglycemia/diabetes, abdominal obesity, hypertriglyceridaemia, low HDL cholesterol and hypertension), which identifies subjects at high risk for forthcoming type 2 diabetes mellitus and cardiovascular (CV) diseases. Recently, a close association between MetS, erectile dysfunction (ED) and male hypogonadism has been reported. In patients with MetS, hypogonadism can exacerbate sexual dysfunction and arteriogenic ED because of its typical symptoms, such as decreased sexual desire and mood disturbances. On the other hand, hypogonadism per se has been associated with an increased risk of CV and overall mortality. Obesity and in particular central obesity is nowadays considered the most important determinant of MetS-induced hypogonadism whereas hypertension and diabetes play a major role in ED associated with MetS. This review analyses the current literature regarding the relationship between ED, MetS and hypogonadism emphasising the epidemiological and psychopathological aspects and stressing the concept that ED subjects are ‘lucky’, because ED offers a unique chance to undergo medical examination and therefore to improve not only their sexual but, most importantly, their overall health.     

k-POD: A Method for k-Means Clustering of Missing Data

The k-means algorithm is often used in clustering applications but its usage requires a complete data matrix. Missing data, however, are common in many applications. Mainstream approaches to clustering missing data reduce the missing data problem to a complete data formulation through either deletion or imputation but these solutions may incur significant costs. Our k-POD method presents a simple extension of k-means clustering for missing data that works even when the missingness mechanism is unknown, when external information is unavailable, and when there is significant missingness in the data.

[Received November 2014. Revised August 2015.]     

Reflections on Changes in the Library and Serials Literature

Abstract

Johnson describes changes in library journal literature topics over the past one hundred years, with a focus on the period between her first Balance Point column in 2003 and this one, her last. She reminisces on her experience as a Balance Point column editor.     

Parameter selection in modified histogram estimates

A multivariate modified histogram density estimate depending on a reference density g and a partition P has been proved to have good consistency properties according to several information theoretic criteria. Given an i.i.d. sample, we show how to select automatically both g and P so that the expected L ₁ error of the corresponding selected estimate is within a given constant multiple of the best possible error plus an additive term which tends to zero under mild assumptions. Our method is inspired by the combinatorial tools developed by Devroye and Lugosi [Devroye, L. and Lugosi, G., 2001, Combinatorial Methods in Density Estimation (New York, NY: Springer–Verlag)] and it includes a wide range of reference density and partition models. Results of simulations are also presented.     

The Relationship Between Sexual Minority Verbal Harassment and Utilization of Health Services: Results from Countywide Risk Assessment Survey (CRAS) 2004

In this article we examine the prevalence of and associations between sexual orientation–based verbal harassment and reported utilization of health services across levels of sexual orientation in a diverse sample of adult recipients of Los Angeles County–funded HIV-related health and social services. Thirty-two percent reported they had experienced verbal harassment, the majority (80.3%) of whom identified as lesbian, gay, or bisexual (LGB). Those who reported being verbally harassed received significantly more services overall than those who were not verbally harassed, and service utilization varied by sexual orientation. These findings inform future efforts to identify and assess social discrimination in health and social service settings.