A Recursive Formulation of the Old Problem of Obtaining Moments from Cumulants and Vice Versa

It seems difficult to find a formula in the literature that relates moments to cumulants (and vice versa) and is useful in computational work rather than in an algebraic approach. Hence I present four very simple recursive formulas that translate moments to cumulants and vice versa in the univariate and multivariate situations.     

Books received

A Wider Perspective Needed Avraham Greenbaum (ed.), Minority Problems in Eastern Europe Between the World Wars, with Emphasis on the Jewish Minority, introduced by Edward Allworth, Hebrew University of Jerusalem, Institute of Advanced Studies. Jerusalem, 1988. pp.viii, 163.

The Jokes of Oppression David A. Harris and Izrail Rabinovich, The Jokes of Oppression: The Humour of Soviet Jews. Northvale, NJ and London: Jason Aronson, 1988. 275pp. $22.50.

A Pleasant Surprise Franti?ek Mi?eje, Revolu?nou Cestou. Spomienky na roky 1938–1948 (On the Path of Revolution: Reminiscences of the Years 1938–1948.) Bratislava: Pravda publishers on behalf of the Institute of Marxism‐Leninism of the Central Committee of the Communist Party of Slovakia, 1988. 232 pp. Illus. Bibl. Index. Kcs 19.00.     

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.     

Adaptive density estimation: A curse of support?

This paper deals with the classical problem of density estimation on the real line. Most of the existing papers devoted to minimax properties assume that the support of the underlying density is bounded and known. But this assumption may be very difficult to handle in practice. In this work, we show that, exactly as a curse of dimensionality exists when the data lie in R^d, there exists a curse of support as well when the support of the density is infinite. As for the dimensionality problem where the rates of convergence deteriorate when the dimension grows, the minimax rates of convergence may deteriorate as well when the support becomes infinite. This problem is not purely theoretical since the simulations show that the support-dependent methods are really affected in practice by the size of the density support, or by the weight of the density tail. We propose a method based on a biorthogonal wavelet thresholding rule that is adaptive with respect to the nature of the support and the regularity of the signal, but that is also robust in practice to this curse of support. The threshold, that is proposed here, is very accurately calibrated so that the gap between optimal theoretical and practical tuning parameters is almost filled.     

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.     

Communicating Contaminant Risks from Sport-Caught Fish: The Importance of Target Audience Assessment

A fish consumption health advisory has existed for New York Lake Ontario sport-caught fish since 1978. Our study objectives were to evaluate the effectiveness of the advisory for reaching potential target audiences and to identify appropriate advisory content, style, and dissemination methods using a risk communication planning model as an evaluation framework. We used a combination of mail surveys and personal interviews with three target audiences (opinion leaders among recreational anglers and charter boat operators, migrant farm workers, and low-income individuals) and two communicator groups (fishery experts and health care experts). The New York Lake Ontario advisory appeared to be successful in reaching and encouraging risk-mitigating fish consumption behavior in recreational angler opinion leaders and low-income individuals but not in migrant farm workers. The advisory may not be reaching two sensitive subpopulations, women of childbearing age and children. Communicators and target audiences differed in their assessments of important information to include in an advisory. The health advisory could be improved with additional information such as risk-reducing cooking and cleaning methods and by diversifying the dissemination methods to reach the variety of audiences who potentially consume Lake Ontario fish.