Prediction based classification for longitudinal biomarkers

Assessment of circulating CD4 count change over time in HIV-infected subjects on antiretroviral therapy (ART) is a central component of disease monitoring. The increasing number of HIV-infected subjects starting therapy and the limited capacity to support CD4 count testing within resource-limited settings have fueled interest in identifying correlates of CD4 count change such as total lymphocyte count, among others. The application of modeling techniques will be essential to this endeavor due to the typically non-linear CD4 trajectory over time and the multiple input variables necessary for capturing CD4 variability. We propose a prediction based classification approach that involves first stage modeling and subsequent classification based on clinically meaningful thresholds. This approach draws on existing analytical methods described in the receiver operating characteristic curve literature while presenting an extension for handling a continuous outcome. Application of this method to an independent test sample results in greater than 98% positive predictive value for CD4 count change. The prediction algorithm is derived based on a cohort of n = 270 HIV-1 infected individuals from the Royal Free Hospital, London who were followed for up to three years from initiation of ART. A test sample comprised of n = 72 individuals from Philadelphia and followed for a similar length of time is used for validation. Results suggest that this approach may be a useful tool for prioritizing limited laboratory resources for CD4 testing after subjects start antiretroviral therapy.     

Canadian Campus Smoking Policies: Investigating the Gap Between Intent and Outcome From a Student Perspective

Abstract

Background: Young adults remain the earliest legal target for the tobacco industry. Against this, the existence of smoking policies would appear to offer some protection to students on campus. However, little research has been conducted into the outcomes of such policies from a student perspective. Methods: The authors conducted 8 focus groups at 4 selected Canadian undergraduate campuses to investigate student perceptions and behaviors resulting from campus smoking policies. Results: Results indicated that student smoking behaviors are minimally impacted by campus smoking policies due to seriously compromised implementation and enforcement. Conclusions: These findings imply that the presence of campus smoking policies and claims of “smoke-free” campuses should not be misinterpreted as achievement and without renewed focus and adequate tobacco control infrastructure, it will remain possible for young adults to initiate and maintain tobacco smoking on campus.     

Determining the effects of intraclass correlation on factorial experiments

This paper considers the effects of the presence of eqmi-correlation between observations in a k-way factorial experiment, A technique to provide unbiased F-tests is also constructed.     

Ethical dilemmas in a professional service context

This paper reports on the results of action research exploring the kinds of ethical problems that confront employees in the professional services industry. Data were collected from a single firm via participant observation methods at eight locations across the country. Issues raised included service delivery, responses to life threatening situations, marketing, client relationships, client entertaining, bribery, billings, as well as intra-firm issues such as support for professional judgments in the field, employee health and safety, and compensation. The paper concludes with an assessment of the utility of the approach taken by the firm, the generalizability of the issues beyond the single case setting, as well as an assessment of the managerial issues related to fostering and sustaining an ethical environment within a business organization.     

Rehabilitation outlooks for rural Louisiana: educational developments,economic trends,and global perspectives

The objective of this article is to examine current medical, economic, and social trends affecting the provision of rehabilitation services for rural citizens with disabilities. While the population of interest is citizens of Louisiana, the concepts are applicable across all geographic boundaries. The article is a review of clinical practice, job placement alternatives, economic trends, and assessment of process applications. It is concluded numerous steps may be taken to enhance the availability and quality of services provided for rural citizens with disabilities: greater statistical inquiry into rural disability trends, increased incorporation of the Internet into all aspects of rural economic and educational developments, further development of distance learning, promotion of sensitivities towards rural cultures, and continued recruitment of rural allied and vocational rehabilitation professionals.     

Identity in political context: lesbian/gay representation in the public sphere

Discourses constructed to represent lesbians and gay men in the public sphere generate an essentialist identity which is both necessary and damaging. Legislative debate illustrates the production of a constrictive and homogeneous identity rejected by many gay/lesbian scholars and activists. Discussion of the rhetorical power of identity claims has produced alternative stances toward variant sexuality. This discussion can be advanced by challenging dominant constructions of civil rights and the public sphere.     

Improving performance in a contracted physician network

Health care organizations face significant performance challenges. Achieving desired results requires the highest level of partnership with independent physicians. Tufts Health Plan invited medical directors of its affiliated groups to participate in a leadership development process to improve clinical, service, and business performance. The design included performance review, gap analysis, priority setting, improvement work plans, and defining the optimum practice culture. Medical directors practiced core leadership capabilities, including building a shared context, getting physician buy-in, and managing outliers. The peer learning environment has been sustained in redesigned medical directors' meetings. There has been significant performance improvement in several practices and enhanced relations between the health plan and medical directors.     

Combining Food Frequency and Survey Data to Quantify Long-Term Dietary Exposure: A Methyl Mercury Case Study

Twenty-four-hour recall data from the Continuing Survey of Food Intake by Individuals (CSFII) are frequently used to estimate dietary exposure for risk assessment. Food frequency questionnaires are traditional instruments of epidemiological research; however, their application in dietary exposure and risk assessment has been limited. This article presents a probabilistic method of bridging the National Health and Nutrition Examination Survey (NHANES) food frequency and the CSFII data to estimate longitudinal (usual) intake, using a case study of seafood mercury exposures for two population subgroups (females 16 to 49 years and children 1 to 5 years). Two hundred forty-nine CSFII food codes were mapped into 28 NHANES fish/shellfish categories. FDA and state/local seafood mercury data were used. A uniform distribution with minimum and maximum blood-diet ratios of 0.66 to 1.07 was assumed. A probabilistic assessment was conducted to estimate distributions of individual 30-day average daily fish/shellfish intakes, methyl mercury exposure, and blood levels. The upper percentile estimates of fish and shellfish intakes based on the 30-day daily averages were lower than those based on two- and three-day daily averages. These results support previous findings that distributions of "usual" intakes based on a small number of consumption days provide overestimates in the upper percentiles. About 10% of the females (16 to 49 years) and children (1 to 5 years) may be exposed to mercury levels above the EPA's RfD. The predicted 75th and 90th percentile blood mercury levels for the females in the 16-to-49-year group were similar to those reported by NHANES. The predicted 90th percentile blood mercury levels for children in the 1-to-5-year subgroup was similar to NHANES and the 75th percentile estimates were slightly above the NHANES.