Process and Results of an Immunization Requirement at the University of Rochester

Abstract

“A Double-Blind Study of Oral Acyclovir for Suppression of Recurrences of Genital Herpes Simplex Virus Infection,” JOHN M. DOUGLAS, et al. Patients with frequently recurring genital herpes were enrolled in a double-blind placebo-controlled trial comparing 200-mg acyclovir capsules, given five or two times daily, with placebo. Of 47 placebo recipients, 44 (94 per cent) had recurrences during the 120-day treatment period, compared with 13 (29 per cent) of 45 patients treated with acyclovir five times daily and 18 of 51 (35 per cent) treated with acyclovir twice daily (P < 0.001 for each regimen compared with placebo). The median time to the first clincial recurrence was 18 days in placebo recipients, compared with over 120 days in both acyclovir-treated groups (P < 0.001 for both groups compared with placebo). The mean monthly recurrence rate during the medication period was 0.86 in placebo recipients, compared with 0.13 in patients treated with acyclovir five times daily and 0.14 in patients treated with acyclovir twice daily (P < 0.001 for both groups compared with placebo). While receiving therapy, 86 of 96 acyclovir-treated patients had over a 50 per cent reduction in their pretreatment recurrence rate. Breakthrough recurrences in acyclovir recipients were of shorter duration and associated with a lower frequency of viral shedding than recurrences in placebo recipients. After medication was discontinued, the subsequent recurrence rate returned to pretreatment frequencies. Daily oral acyclovir was well tolerated. We conclude that oral acyclovir given for four months markedly reduces but does not completely prevent recurrences of genital herpes and does not influence the long-term natural history of the disease. (New England Journal of Medicine 1984 July;310:1551–6.)     

Statistical analysis of a two-unit dependent repairable system

Maximum likelihood estimators are investigated a for lr-out-of 2:G repairable system when failures and repairs are statistically dependent. Under two censoring schemes Accelerated Life Testing Procedure (ALTP) is used to obtain the estimates. Information matrices are supplied and a special case when the failure and repair phenomenon are independent of each other is considered.     

Cultural Consequences on Excellence in Public Diplomacy

The purpose of this study is to advance the contextual study of public diplomacy—the inquiry into the influences of a government's contextual variables on its practice and management of public diplomacy. To meet this aim, this study investigated the empirical associations between Hofstede's cultural dimensions and Excellence in public diplomacy, a conception of excellence in public diplomacy developed from the Excellence study, based on survey data from 52 embassies in Washington, DC. The findings suggest that the uncertainty avoidance dimension has substantial and significant empirical associations with Excellence in public diplomacy. Additionally, not only low uncertainty avoidance cultures but also individualist and low power distance cultures are more conducive to the Excellence than are their counterparts. Nonetheless, the findings have an implication that, in terms of associational magnitude, the overall contextual effects of societal culture on the Excellence may not be strong.     

Outcomes Assessment of Role-Play Scenarios for Teaching Responsible Conduct of Research

We describe the summative assessment of role-play scenarios that we previously developed to teach central topics in the responsible conduct of research (RCR) to graduate students in science and engineering. Interviews with role-play participants, with participants in a case discussion training session, and with untrained students suggested that role-playing might promote a deeper appreciation of RCR by shifting the focus away from wanting to simply “know the rules.” We also present the results of a think-aloud case analysis study and describe the development of a behaviorally-anchored rating scale (BARS) to assess participants' case analysis performance.     

Detecting homogeneous segments in DNA sequences by using hidden Markov models

In recent years there has been a rapid growth in the amount of DNA being sequenced and in its availability through genetic databases. Statistical techniques which identify structure within these sequences can be of considerable assistance to molecular biologists particularly when they incorporate the discrete nature of changes caused by evolutionary processes. This paper focuses on the detection of homogeneous segments within heterogeneous DNA sequences. In particular, we study an intron from the chimpanzee α-fetoprotein gene; this protein plays an important role in the embryonic development of mammals. We present a Bayesian solution to this segmentation problem using a hidden Markov model implemented by Markov chain Monte Carlo methods. We consider the important practical problem of specifying informative prior knowledge about sequences of this type. Two Gibbs sampling algorithms are contrasted and the sensitivity of the analysis to the prior specification is investigated. Model selection and possible ways to overcome the label switching problem are also addressed. Our analysis of intron 7 identifies three distinct homogeneous segment types, two of which occur in more than one region, and one of which is reversible.     

Designing fractional two-level experiments with nested error structures

A common feature of experiments with a random blocking factor and splitplot experiments is their nested error structure. This paper proposes a general strategy to handle fractional two-level experiments with such error structures. The strategy aims to create error strata with sufficient numbers of contrasts to separate active effects from inactive effects. The strategy also details the construction of treatment generators, given the constraints of a predetermined error structure. The key elements of the strategy are illustrated with a chemical experiment that has 16 factors and 32 runs blocked according to working days, and a cheese-making experiment that has 11 factors and 128 runs, divided over milk supplies as whole plots, curds productions as subplots and sets of identically treated cheeses as sub-subplots.     

Population Change and Changing Educational Attainment of Ethnic Groups in the United States, 1980–2000

This study assesses the effect of population change on decade changes in the educational attainments of country of origin populations in the United States. Our data are derived from decennial censuses, NLMS, the World Bank, and INS. We find that changes in the share of country of origin populations with one or more years of post-secondary schooling are associated with selected components of population change during the 1980–1990 and 1990–2000 decades. The specific components include survivors during the decade, in-migration, and emigration of the foreign-born. Likewise, intra-generational mobility is found to be an important determinant of changes in educational attainment. The discussion addresses limitations of the data and suggests directions for future research as well as policy implications.     

On the asymptotic distribution of Cook's distance in logistic regression models

It sometimes occurs that one or more components of the data exert a disproportionate influence on the model estimation. We need a reliable tool for identifying such troublesome cases in order to decide either eliminate from the sample, when the data collect was badly realized, or otherwise take care on the use of the model because the results could be affected by such components. Since a measure for detecting influential cases in linear regression setting was proposed by Cook [Detection of influential observations in linear regression, Technometrics 19 (1977), pp. 15–18.], apart from the same measure for other models, several new measures have been suggested as single-case diagnostics. For most of them some cutoff values have been recommended (see [D.A. Belsley, E. Kuh, and R.E. Welsch, Regression Diagnostics: Identifying Influential Data and Sources of Collinearity, 2nd ed., John Wiley & Sons, New York, Chichester, Brisban, (2004).], for instance), however the lack of a quantile type cutoff for Cook's statistics has induced the analyst to deal only with index plots as worthy diagnostic tools. Focussed on logistic regression, the aim of this paper is to provide the asymptotic distribution of Cook's distance in order to look for a meaningful cutoff point for detecting influential and leverage observations.