9 resultados para multi-way analysis
em DigitalCommons@The Texas Medical Center
Resumo:
This study investigates the prevalence of burnout among a sample of Texas psychologists and psychological associates as well as differences between the three categories of practitioners within that group (Licensed Psychology Health Care Providers (LPHCP), Licensed Psychologists - Certified Psychologists (LP-CP), Psychological Associates (PA)).^ The Maslach Burnout Inventory and a questionnaire seeking demographic information was used in this cross-sectional survey. Sample size was 654. A stratified proportionate random sample of Texas Psychologists was drawn. The response rate based on usable returns was 55% (n = 359). General demographic characteristics were determined mainly by frequency distributions. For comparing means of samples, t and multiple range tests were used. A series of one-way and two-way analysis of variance procedures were used to compare subgroup differences in burnout.^ The universe was representative for the sample and for the three categories of psychologists. Urban subjects were more likely to respond, as were male PAs. Practitioners were as likely male as female, working in an urban area, in their present job eight years, and in the occupation for fifteen. The LPHCP group were older, had been in psychology and at their present job longer, and were more likely to belong to both state and local professional organizations than the other two groups. Males outnumbered females in this group and in LP-CPs. This gender trend was reversed for PAs. Of the total sample, 76% reported high job satisfaction and 77% had high levels of perceived job autonomy. There was no significant difference between the study sample and the mental health norms in emotional exhaustion (EE). Our sample had significantly less feelings of depersonalization (DP) and higher feelings of personal accomplishment (PA). Psychological Associates felt significantly less personal accomplishment than the other groups. Predictors for the total sample indicated younger practitioners and those with low job satisfaction had significantly higher burnout, as did males when compared to their female cohorts. Some types of jobs were more likely to contribute to burnout than others. Membership in their local area professional organization lessened the chances for burnout significantly. Predictors for categories of psychologists indicated that males in the LPHCP and LP-CP groups were at higher risk than females. Further, for LP-CPs low job satisfaction and job autonomy, as well as job sites, were significant. Those in this group who worked as school psychologists were at the highest risk for burnout. Job dissatisfaction was the major predictor of burnout for psychological associates. Practitioners working in state or government agencies, school systems and administrative jobs generally had higher burnout than those on a university faculty or in private practice. (Abstract shortened by UMI.) ^
Resumo:
A new technique for the detection of microbiological fecal pollution in drinking and in raw surface water has been modified and tested against the standard multiple-tube fermentation technique (most-probable-number, MPN). The performance of the new test in detecting fecal pollution in drinking water has been tested at different incubation temperatures. The basis for the new test was the detection of hydrogen sulfide produced by the hydrogen sulfide producing bacteria which are usually associated with the coliform group. The positive results are indicated by the appearance of a brown to black color in the contents of the fermentation tube within 18 to 24 hours of incubation at 35 (+OR-) .5(DEGREES)C. For this study 158 water samples of different sources have been used. The results were analyzed statistically with the paired t-test and the one-way analysis of variance. No statistically significant difference was noticed between the two methods, when tested 35 (+OR-) .5(DEGREES)C, in detecting fecal pollution in drinking water. The new test showed more positive results with raw surface water, which could be due to the presence of hydrogen sulfide producing bacteria of non-fecal origin like Desulfovibrio and Desulfomaculum. The survival of the hydrogen sulfide producing bacteria and the coliforms was also tested over a 7-day period, and the results showed no significant difference. The two methods showed no significant difference when used to detect fecal pollution at a very low coliform density. The results showed that the new test is mostly effective, in detecting fecal pollution in drinking water, when used at 35 (+OR-) .5(DEGREES)C. The new test is effective, simple, and less expensive when used to detect fecal pollution in drinking water and raw surface water at 35 (+OR-) .5(DEGREES)C. The method can be used for qualitative and/or quantitative analysis of water in the field and in the laboratory. ^
Resumo:
Measurements of the natural background radiation have been made at numerous places throughout the world. Very little work in this field has been done in developing countries. In Mexico the natural radiation to which the population is exposed has not been assessed. This dissertation represents a pioneer study in this environmental area. The radiation exposure which occupants within buildings receive as a result of naturally occurring radionuclides present in construction materials is the principal focus.^ Data were collected between August 1979 and November 1980. Continuous monitoring was done with TLDs placed on site for periods of 3 to 6 months. The instrumentation used for "real-time" measurements was a portable NaI (Tl) scintillation detector. In addition, radiometric measurements were performed on construction materials commonly used in Mexican homes.^ Based on TLD readings taken within 75 dwellings, the typical indoor exposure for a resident of the study area is 9.2 (mu)Rh('-1). The average reading of the 152 indoor scintillometer surveys was 9.5 (mu)Rh('-1), the outdoor reading 7.5 (mu)Rh('-1). Results of one-way and multi-way analyses of the exposure data to determine the effect due to building materials type, geologic subsoil, age of dwelling, and elevation are also presented. The results of 152 indoor scintillometer surveys are described. ^
Resumo:
Background. The increasing prevalence of overweight among youth in the United States, and the parallel rise in related medical comorbidities has led to a growing need for efficient weight-management interventions. Purpose. The aim of this study was to evaluate the effects of the Choosing Health and Sensible Exercise (C.H.A.S.E.) childhood obesity prevention program on Body Mass Index (BMI), physical activity and dietary behaviors. Methods. This study utilized de-identified data collected during the fall 2006 session of the C.H.A.S.E. program. A total of 65 students at Woodview Elementary School and Deepwater Elementary School participated in this intervention. The C.H.A.S.E. program is a 10-week obesity prevention program that focuses on nutrition and physical activity education. Collection of height and weight data, and a health behavior survey was conducted during the first and last week of the intervention. Paired t-tests were used to determine statistically significant differences between pre- and post-intervention measurements. One-way analysis of variance was used to adjust for potential confounders, such as gender, age, BMI category ("normal weight", "at risk overweight", or "overweight"), and self-reported weight loss goals. Data were analyzed using STATA, v. 9.2. Results. A significant decrease in mean BMI (p< 0.05) was found after the 10-week intervention. While the results were statistically significant for the group as a whole, changes in BMI were not significant when stratified by age, sex, or ethnicity. The mean overall scores for the behavior survey did not change significantly pre- and post-intervention; however, significant differences were found in the dietary intention scale, indicating that students were more likely to intend to make healthier food choices (p<0.05). No statistically significant decreases in BMI were found when stratified for baseline BMI-for-age percentiles or baseline weight loss efforts (p>0.05). Conclusion. The results of this evaluation provide information that will be useful in planning and implementing an effective childhood obesity intervention in the future. Changes in the self-reported dietary intentions and BMI show that the C.H.A.S.E. program is capable of modifying food choice selection and decreasing BMI. Results from the behavior questionnaire indicate that students in the intervention program were making changes in a positive direction. Future implementation of the C.H.A.S.E. program, as well as other childhood obesity interventions, may want to consider incorporating additional strategies to increase knowledge and other behavioral constructs associated with decreased BMI. In addition, obesity prevention programs may want to increase parental involvement and increase the dose or intensity of the intervention. ^
Resumo:
Interaction effect is an important scientific interest for many areas of research. Common approach for investigating the interaction effect of two continuous covariates on a response variable is through a cross-product term in multiple linear regression. In epidemiological studies, the two-way analysis of variance (ANOVA) type of method has also been utilized to examine the interaction effect by replacing the continuous covariates with their discretized levels. However, the implications of model assumptions of either approach have not been examined and the statistical validation has only focused on the general method, not specifically for the interaction effect.^ In this dissertation, we investigated the validity of both approaches based on the mathematical assumptions for non-skewed data. We showed that linear regression may not be an appropriate model when the interaction effect exists because it implies a highly skewed distribution for the response variable. We also showed that the normality and constant variance assumptions required by ANOVA are not satisfied in the model where the continuous covariates are replaced with their discretized levels. Therefore, naïve application of ANOVA method may lead to an incorrect conclusion. ^ Given the problems identified above, we proposed a novel method modifying from the traditional ANOVA approach to rigorously evaluate the interaction effect. The analytical expression of the interaction effect was derived based on the conditional distribution of the response variable given the discretized continuous covariates. A testing procedure that combines the p-values from each level of the discretized covariates was developed to test the overall significance of the interaction effect. According to the simulation study, the proposed method is more powerful then the least squares regression and the ANOVA method in detecting the interaction effect when data comes from a trivariate normal distribution. The proposed method was applied to a dataset from the National Institute of Neurological Disorders and Stroke (NINDS) tissue plasminogen activator (t-PA) stroke trial, and baseline age-by-weight interaction effect was found significant in predicting the change from baseline in NIHSS at Month-3 among patients received t-PA therapy.^
Resumo:
An investigation of (a) month/season-of-birth as a risk factor and (b) month/season-of-treatment initation as a prognostic factor in acute lymphoblastic leukemia (ALL) in children, 0-15 years of age, was conducted. The study population used was that of the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute and included children diagnosed and treated for ALL from 1973-1986. Two separate sets of analyses using different exclusion criteria led to similar results. Specifically, the inability to reject the null hypothesis of no significant difference in the variation of monthly/seasonal incidence rates among children residing within the 10 SEER sites using either cosinor analysis or one-way analysis of variance. No association was established between month/season of treatment initiation and survival in ALL among children using either Kaplan-Meier or cosinor analysis. In separate Kaplan-Meier analyses, age, gender, and treatment type were each found to be significant univariate prognostic factors for survival, however. ^
Resumo:
Many phase II clinical studies in oncology use two-stage frequentist design such as Simon's optimal design. However, they have a common logistical problem regarding the patient accrual at the interim. Strictly speaking, patient accrual at the end of the first stage may have to be suspended until all patients have events, success or failure. For example, when the study endpoint is six-month progression free survival, patient accrual has to be stopped until all outcomes from stage I is observed. However, study investigators may have concern when accrual is suspended after the first stage due to the loss of accrual momentum during this hiatus. We propose a two-stage phase II design that resolves the patient accrual problem due to an interim analysis, and it can be used as an alternative way to frequentist two-stage phase II studies in oncology. ^
Resumo:
Online courses will play a key role in the high-volume Informatics education required to train the personnel that will be necessary to fulfill the health IT needs of the country. Online courses can cause feelings of isolation in students. A common way to address these feelings is to hold synchronous online "chats" for students. Conventional chats, however, can be confusing and impose a high extrinsic cognitive load on their participants that hinders the learning process. In this paper we present a qualitative analysis that shows the causes of this high cognitive load and our solution through the use of a moderated chat system.
Resumo:
Background and Objective. Ever since the human development index was published in 1990 by the United Nations Development Programme (UNDP), many researchers started searching and corporative studying for more effective methods to measure the human development. Published in 1999, Lai’s “Temporal analysis of human development indicators: principal component approach” provided a valuable statistical way on human developmental analysis. This study presented in the thesis is the extension of Lai’s 1999 research. ^ Methods. I used the weighted principal component method on the human development indicators to measure and analyze the progress of human development in about 180 countries around the world from the year 1999 to 2010. The association of the main principal component obtained from the study and the human development index reported by the UNDP was estimated by the Spearman’s rank correlation coefficient. The main principal component was then further applied to quantify the temporal changes of the human development of selected countries by the proposed Z-test. ^ Results. The weighted means of all three human development indicators, health, knowledge, and standard of living, were increased from 1999 to 2010. The weighted standard deviation for GDP per capita was also increased across years indicated the rising inequality of standard of living among countries. The ranking of low development countries by the main principal component (MPC) is very similar to that by the human development index (HDI). Considerable discrepancy between MPC and HDI ranking was found among high development countries with high GDP per capita shifted to higher ranks. The Spearman’s rank correlation coefficient between the main principal component and the human development index were all around 0.99. All the above results were very close to outcomes in Lai’s 1999 report. The Z test result on temporal analysis of main principal components from 1999 to 2010 on Qatar was statistically significant, but not on other selected countries, such as Brazil, Russia, India, China, and U.S.A.^ Conclusion. To synthesize the multi-dimensional measurement of human development into a single index, the weighted principal component method provides a good model by using the statistical tool on a comprehensive ranking and measurement. Since the weighted main principle component index is more objective because of using population of nations as weight, more effective when the analysis is across time and space, and more flexible when the countries reported to the system has been changed year after year. Thus, in conclusion, the index generated by using weighted main principle component has some advantage over the human development index created in UNDP reports.^