OBJECTIVE:To characterize mortality in persons diagnosed with primary pulmonary hypertension and to investigate factors associated with survival.DESIGN:Registry with prospective follow-up.SETTING:Thirty-two clinical centers in the United States participating in the Patient Registry for the Characterization of Primary Pulmonary Hypertension supported by the National Heart, Lung, and Blood Institute.PATIENTS:Patients (194) diagnosed at clinical centers between 1 July 1981 and 31 December 1985 and followed through 8 August 1988.MEASUREMENTS:At diagnosis, measurements of hemodynamic variables, pulmonary function, and gas exchange variables were taken in addition to information on demographic variables, medical history, and life-style. Patients were followed for survival at 6-month intervals.MAIN RESULTS:The estimated median survival of these patients was 2.8 years (95% Cl, 1.9 to 3.7 years). Estimated single-year survival rates were as follows: at 1 year, 68% (Cl, 61% to 75%); at 3 years, 48% (Cl, 41% to 55%); and at 5 years, 34% (Cl, 24% to 44%). Variables associated with poor survival included a New York Heart Association (NYHA) functional class of III or IV, presence of Raynaud phenomenon, elevated mean right atrial pressure, elevated mean pulmonary artery pressure, decreased cardiac index, and decreased diffusing capacity for carbon monoxide (DLCO). Drug therapy at entry or discharge was not associated with survival duration.CONCLUSIONS:Mortality was most closely associated with right ventricular hemodynamic function and can be characterized by means of an equation using three variables: mean pulmonary artery pressure, mean right atrial pressure, and cardiac index. Such an equation, once validated prospectively, could be used as an adjunct in planning treatment strategies and allocating medical resources.

The conduction characteristics of La 1/3 Ca 2/3 MnO 3 (LCMO) films grown by pulsed laser deposition were investigated. The devices exhibit bipolar resistive switching effect with intermediate conduction states achievable by the application of positive and negative voltage ramps. The I-V curves are modeled using a nonlinear memristive approach based on the double-diode equation and the solution of the generalized logistic differential equation.

Missing data estimation, “hot deck” and “cold deck”† Paul S. Levy, Paul S. Levy RTI International, Research Triangle Park, NC, USASearch for more papers by this author Paul S. Levy, Paul S. Levy RTI International, Research Triangle Park, NC, USASearch for more papers by this author First published: 29 September 2014 https://doi.org/10.1002/9781118445112.stat05052Citations: 1 †This article was originally published online in 2005 in Encyclopedia of Biostatistics, © John Wiley & Sons, Ltd and republished in Wiley StatsRef: Statistics Reference Online, 2014. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Wiley StatsRef: Statistics Reference OnlineBrowse other articles of this reference work:BROWSE BY TOPICBROWSE A-Z RelatedInformation

Abstract This entry presents concepts involved in determination of sample size adequacy in sample surveys. There is a broad discussion of issues such as stratification, sampling without replacement, finite population corrections, sampling of clusters, sampling in more than one stage, and unequal weighting of observations that have a profound effect on the distribution of estimates and on the sample sizes necessary to construct reliable estimates. We include formulas for determining sample size adequacy for some of the most widely used sample designs and some practical guidelines for statistical consulting on this issue. A set of references to texts and specific articles is included.

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This chapter contains sections titled: World Health Organization EPI Surveys: A Modification of PPS Sampling for Use in Developing Countries Quality Assurance Sampling Sample Sizes for Longitudinal Studies Estimation of Prevalence of Diseases from Screening Studies Estimation of Rare Events: Network Sampling Estimation of Rare Events: Dual Samples Estimation of Characteristics for Local Areas: Synthetic Estimation Extraction of Sensitive Information: Randomized Response Techniques Summary

This chapter contains sections titled: Motivation for Not Sampling Clusters with Equal Probability Two General Classes of Estimators Valid for Sample Designs in Which Units Are Selected with Unequal Probability Probability Proportional to Size Sampling Further Comment on PPS Sampling Summary