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Systematic Sample (systematic + sample)
Selected AbstractsHealth Status among Emergency Department Patients Approximately One Year after Consecutive Disasters in New York CityACADEMIC EMERGENCY MEDICINE, Issue 10 2005William George Fernandez MD Abstract Objectives: Emergency department (ED) patients with disaster-related experiences may present with vague symptoms not clearly linked to the event. In 2001, two disasters in New York City, the World Trade Center disaster (WTCD) and the subsequent American Airlines Flight 587 crash, presented an opportunity to study long-term consequences of cumulative disaster exposure (CDE) on health-related quality of life (HRQOL) among ED patients. Methods: From July 15 to October 30, 2002, a systematic sample of stable, adult patients from two EDs in New York City were enrolled. Participants completed a self-administered questionnaire. The Short Form 36 (SF-36) was used to assess overall health status. Bivariate analyses were conducted to identify individual correlates of worsening health status. Multivariate regression was performed to identify the association between various factors and overall health status, while controlling for relevant sociodemographic variables. Results: Four hundred seventy-one patients (54.6% female) participated. The participation rate was 73.4%. One hundred sixty-one participants (36%) reported direct, indirect, or occupational exposure to the WTCD; 55 (13.3%) had direct, indirect, or occupational exposure to the plane crash; 33 (8.1%) had both exposures. In separate multivariate models, CDE predicted lower SF-36 scores for general health (p < 0.0096), mental health (p < 0.0033), and bodily pain (p < 0.0046). Conclusions: In the year following mass traumatic events, persons with CDE had lower overall health status than those with one or no disaster exposure. Clinicians should consider the impact that traumatic events have on the overall health status of ED patients in the wake of consecutive disasters. [source] Periapical status and quality of endodontic treatment in an adult Irish populationINTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2005J. J. Loftus Abstract Aim, To determine the prevalence of apical periodontitis and the quality of root fillings in an adult Irish population using a retrospective analysis of orthopantomograms (OPGs). Methodology, A systematic sample of clinical records and OPGs of 302 adult patients attending the Dublin Dental Hospital, Ireland, were screened by two examiners to determine the quality of root canal treatment and the prevalence of apical periodontitis. The operators who carried out the treatment were unknown. Two examiners inspected OPGs after inter-examiner correlation. European Society of Endodontology (ESE) guidelines were used to determine adequacy of root treatment. Results, Of the 7427 teeth examined 2% had root fillings. Apical periodontitis was evident in 1.6% of all nonroot filled teeth whilst 33.1% of the subjects had at least one tooth with apical periodontitis. Of the root filled teeth, 25% had apical periodontitis and 52.6% were considered technically inadequate by ESE guidelines. There was a statistically significant (P < 0.05) negative correlation between the quality of the root fillings and the prevalence of apical periodontitis. Posterior root filled teeth (premolars and molars) had a greater prevalence of apical periodontitis than anterior root filled teeth. Conclusions, The technical quality of root fillings in an adult Irish population was poor and was consistent with a high prevalence of apical periodontitis. [source] Sampling and concentration values of incomplete bibliographiesJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 4 2002L. Egghe This article studies concentration aspects of bibliographies. More, in particular, we study the impact of incompleteness of such a bibliography on its concentration values (i.e., its degree of inequality of production of its sources). Incompleteness is modeled by sampling in the complete bibliography. The model is general enough to comprise truncation of a bibliography as well as a systematic sample on sources or items. In all cases we prove that the sampled bibliography (or incomplete one) has a higher concentration value than the complete one. These models, hence, shed some light on the measurement of production inequality in incomplete bibliographies. [source] Smoking habits in adolescents with mild to moderate asthmaPEDIATRIC PULMONOLOGY, Issue 3 2004Eyal Zimlichman MD Abstract To study the impact of mild to moderate asthma on smoking habits in adolescents. Specifically, we tested the hypothesis that asthma does not prevent adolescents from smoking. A research questionnaire, filled by a systematic sample of military personnel upon enrolment to service in the Israeli Defense Force (IDF), was analyzed. Conscripts were asked to voluntarily fill (after obtaining a signed informed consent) a research questionnaire about their medical history, and several health related topics including smoking. This database was matched with the military medical profile of the soldier, which includes the patient asthma status. Overall, 38,047 young adults were included in this study. There was a significant increase in the rate of mild to moderate asthma, from the mid-1980's to date. During the 1980's and early 1990's, asthmatics smoked significantly less frequently (20,22%) than non-asthmatics (25,27%). In the mid- to late-1990's, the smoking rates increased relatively more in asthmatics, to the point that in the last 8 years of this study, they were found to be almost identical in both groups, at a rate of approximately 30%. The presence of asthma is not a powerful motivating agent to prevent from smoking. It is likely that smoking asthmatic teenagers are at risk for suboptimal lung growth, and as young adults, they will become at greater risk of lung function deterioration. We suggest that primary care physicians, caring for asthma in children, adolescents, and young adults, should explain the particular risks generated by tobacco smoking. © 2004 Wiley-Liss, Inc. [source] Response rate and nonresponse bias in a questionnaire survey of dentistsCOMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 1 2005Peter Parashos Abstract , Objectives:, (a) To report on response rate and nonresponse bias of a questionnaire survey of dentists. (b) To make recommendations for future questionnaire survey research in dentistry. Methods:, A questionnaire was mailed to a stratified systematic sample of 908 Australian dentists. The strategy included three mailings, a final telephonic contact, university stationery, paid reply envelopes and personalized correspondence. Nonresponse bias was assessed by comparing responses to a simple ,yes/no' question from each contact (late responders), and by comparing demographic information (nonresponders). Results:, The response rate achieved was 87% and there was no evidence of nonresponse bias based on practice location or year of graduation. The cumulative proportions of ,yes/no' responses essentially remained constant after each contact, but significantly more late responders answered in the negative to the test question than did early responders. The telephonic contact aided in the identification of nonparticipants and ineligible units. Conclusions:, The current survey indicates that differences in data between early and nonresponders can occur despite there being no demographic differences. Therefore, assessment of nonresponse bias based on demographic data alone would seem to be insufficient. Questionnaire survey research must first be based on sound sampling techniques, and then on achieving as high a response rate as possible using the many incentives available. [source] Systematic sample design for the estimation of spatial meansENVIRONMETRICS, Issue 1 2003Luis Ambrosio Flores Abstract This article develops a practical approach to undertaking systematic sampling for the estimation of the spatial mean of an attribute in a selected area. A design-based approach is used to estimate population parameters, but it is combined with elements of a model-based approach in order to identify the spatial correlation structure, to evaluate the relative efficiency of the sample mean under simple random and systematic sampling, to estimate sampling error and to assess the sample size needed in order to achieve a desired level of precision. Using two case studies (land use estimation and weed seedbank in soil) it is demonstrated how the practical basis for the design of systematic samples provided in this work should be applied and it is shown that if the spatial correlation is ignored the sampling error of the sample mean and the sample size needed in order to achieve a desired level of precision with systematic sampling are overestimated. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||