Transportation research regularly relies on data exhibiting both space and time dimensions. Thanks to the rise of smartphones, Bluetooth, and other devices, geo-referenced data collection enables application of more behaviorally realistic -- but complex -- models that account for spatial autocorrelation, temporal correlation, and possible time-space interactions (e.g., time-lagged effects from a neighboring unit's response). One promising area is crash count prediction, where crash frequencies (and severities) at zones, intersections, and along roadways will generally exhibit some spatial relationships, due to missing variables, causal mechanisms, and other ties. This dissertation work proposes and estimates a spatial multivariate count model and provides two case studies to implement such model. One case study is in the context of pedestrian-vehicle crash counts across zones in Austin, Texas, while accounting for network features (e.g., lane-miles and intersection density), land use factors (such as land use entropy and residential accessibility to commercial activities), population and job densities, and school access. The other case study pertains to new firm births by industries across U.S. counties while controlling for population density, agglomeration economies (e.g., percentage of firms with more than 100 people), wealth, and median age. The new model specification captures region-wide heterogeneity (thanks to extra variation introduced by the lognormal component in the mean crash-rate specification), correlations across two (or more) count types (in the same zone), and spatial autocorrelation among unobserved components. This new approach and associated application allow analysts to distinguish covariates' effects on multivariate crash and other counts from spatial spillover effects and cross-response correlations. This work adds to the literature by providing guidance on what types of specifications best reflect spatial count data while facilitating estimation (using large data sets) and illuminating the level and nature of spatial autocorrelation, multivariate correlation, and region-wide (latent) heterogeneity that exists in crash data after controlling for a host of observable factors. / text

Background: China accounts for a quarter of the total number of induced abortion worldwide. Induced abortion is considered as one of the risk factors for adverse pregnancy outcome in subsequent pregnancy. The effects of induced abortion on premature delivery were investigated in both China and western countries, and most of the studies showed that increased risk of preterm birth was associated with increasing number of induced abortion. However, the association between low birth weight (LBW) and multiple induced abortions is still controversial. Objectives: To explore the association between LBW and previous induced abortion history, and to investigate the effects of preterm birth on the association. Methods: This case-control study used data from the Neonatal Intensive Care Unit (NICU), Nan Fang Hospital, between December 2011 and June 2012. We recruited 402 LBW (less than 2500 g) infants as our case group and 407 normal weight infants as the control group. Chi-square test and t-test were used for descriptive analysis. Multivariate logistic regression was run to yield odds ratios (OR) of LWB for multiple induced abortion adjusting for sex, birth order, maternal previous diseases and age, antenatal care received, and inter-pregnancy interval. Mediation effect of preterm status was investigated. Results: We observed a higher proportion of women with multiple induced abortions in LBW group (18.4% versus 11.1%, p value=0.003). Mothers with previous multiple induced abortion were 68.3% (95% confidence interval (CI): 11.0% to 155.3%) more likely to have LWB infants, compared with those who did not have induced abortion history or only once. After adjustment also for preterm status, the adjusted OR reduced to 1.332 (95% CI: 0.682 to 2.602) and the association became non-significant. Mediation test confirmed that preterm status was a mediator factor between multiple induced abortion and LBW. Conclusion: Overall, multiple abortions had an effect on LBW mainly through shortening the gestational duration of infants. Either premature delivery or LBW, the effect of multiple abortions on subsequent pregnancy was confirmed in this study. To reduce the perinatal mortality and morbidity, it is not enough only through postpartum care for preterm birth and LBW. The prevention and intervention strategies are urgently needed for reducing the induced abortion rate. / published_or_final_version / Public Health / Master / Master of Public Health

published_or_final_version / Comparative Asian Studies / Master / Master of Arts

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Regression problems in which predictors are measured with error have been studied by statisticians and researchers for many years. Measurement error in predictors creates biases in estimated regression coefficients, and hence models that address this are extremely important. These models are especially important in perinatal research since errors in gestational age can have serious effects. / The presence of measurement error in gestational age can lead to poor estimation of fetal growth and risk of mortality and morbidity, and can compromise statistical analyses [32, 39]. Since various obstetric choices are made based on birth weight distributions by gestational age, it is important to obtain plausible birthweight-gestational-age combinations. / Berry et al. [3] propose a Bayesian approach to modeling a flexible regression function in the presence of measurement error, where the regression function is modeled using smoothing splines and regression P-splines. These methods are applied to population-based data from U.S. birth certificates, which results in realistic birthweight-gestational age combinations.

The predictors of birthweight (scBWT) in normal pregnancy are well established. The objectives of this study were to characterize and determine predictors of scBWT among women diagnosed with scGDM. A cohort of 436 scGDM full-term pregnancies (followed 1978-1989) were examined using data abstracted from the Royal Victoria Hospital Antenatal Diabetic Clinic charts and McGill Obstetric and Neonatal Database. Women were treated with insulin and/or diet. Dietary treatment (mean 2047 kcal/d) significantly decreased the rate of weight gain and mean fasting plasma glucose (scFPG). Regression analysis identified several predictors of scBWT (mean 3520 g): prepregnancy body mass, height, smoking, pre-diagnostic rate of weight gain, scFPG, gestational age, infant gender, and length of treatment. Stratification by body mass indicated that among non-obese women with scGDM, scFPG and length of treatment were not significant predictors of scBWT. In conclusion, since women with normal pregravid mass and prediagnostic weight gain are at lower risk of high scBWT, these require consideration, in addition to plasma glucose criteria, when treating scGDM.

The present study "Knowledge, Attitudes, and Practices of Family Planning 'Methods in Rural Nepal" was conducted to assess the situation of fertility behavior and use of family planning methods. It attempted to collect reliable data on reproductive behavior; contraceptive knowledge, attitudes, and practices; and family size preferences.The immediate objectives of the study were to assess the level of knowledge, attitudes, and practices of family planning methods; to assess the contribution of governmental and non-governmental programs; and recommend appropriate measures and suggestions for the further improvement of the programs.As a representation of rural Nepal, Banganga Village planning office, and the households were randomly selected from the list by the team supervisor. Eligible households selected included all of those in which there was a currently married couple in which either spouse aged between 15 and 45 years of age were present. There were a total of 150 couples identified as eligible for interview and all were successfully interviewed.A structured interview schedule was developed by the researcher, which was sent to Nepal with detailed guidelines for training and management of interviewers. The final editing of all collected survey instruments was carried out by the researcher with the advice of the members of the thesis committee. Later, those instruments were coded and entered in the computer for the purpose of statistical analysis.Based on statistical analysis, it was found that 60.7 percent of the total respondents have heard of at least one of the methods of family planning. However, only 11.3 percent of them have ever used a particular method of family planning. The current use of contraception is also 11.3 percent which is slightly lower than the level found in a 1986 national survey (15.1%). This shows a great disparity between the knowledge and practice of family planning methods.The major reasons given by respondents for not using any family planning method were bad side effects and the desire to have more children. This suggests that program managers and policy makers in Nepal must develop improved information and communication strategies in order to increase the rate of acceptance of family planning.Of the 11.3 percent of the sample who are current users of contraceptive methods, sterilization constitutes as high as 82.4 percent which indicates that family planning is very popular insynonymous with sterilization. This clearly indicates that the concept of birth spacing has not been Nepal.A further finding was that the family planning program is reaching proportionately more literate than illiterate people. This necessitates formation of effective strategies by the concerned agencies which will increase the acceptance rate among illiterate people. This is extremely significant since more than 75 percent of the total population is still illiterate and the majority of them live in rural Nepal. / Department of Sociology

Rapid population growth is now one of the biggest socio-economic and consequently, health problems in the world. The significance of this dramatic increase in population becomes apparent when the limited possibilities of socio-economic growth are considered among developing countries. The use of modern contraceptives in order to control birth rates, on the other hand, is rather limited in these countries. / The present study investigates the knowledge and attitudes of family planning programs by Iranian males, who play a major role in all familial decision-making, including the practice of family planning. This research examines subjects' reasoning strategies about practicing family planning. A sample of sixty laborers with various levels of formal education were selected and some methods developed within the domain of cognitive psychology were used in analyzing the data. / The results showed that males, as proposed, play a vital role in decision-making regarding the practice of family planning. Formal education appears to have no significant impact on the subjects' knowledge and attitudes toward issues of family planning. Furthermore, early age of marriage, particularly with respect to the girls, appears to be an accepted phenomenon and has strong roots in the belief systems of the population. / This research has implications for developing educational programs in the domain of health. It is proposed that future research should devote considerable effort to better understand the role of the males in the process of decision-making regarding the practice of family planning.