PhD Thesis

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Application of Complex Lifetime Models for Analysis of Product Reliability Data
(University of Rajshahi, 2016) Ruhi, Sabba; RezaulKarim, Md.
Proper data collection and analysis are very important for effective investigation of product reliability. Data is critical for building and selecting suitable statistical models and model provides new insights for improvements to maintenance and management operations in manufacturing industries. Regarding variations in product quality and reliability, component nonconformance and assembly error are two important problems which occur frequently in manufacturing industries. In such situations, the complex lifetime models are required for analyzing product reliability data. This thesis proposes a general model for modeling the effects of quality variation. This model includes the mixture model and competing risk model as the special cases. The thesis applies these models for analysis of three sets of product reliability data - Aircraft windshield failure data, Battery failure data and Hydraulic pump failure data. A set of competitive 2-fold and 3-fold mixture models are considered for modeling the data sets. The maximum likelihood estimation method via the Expectation Maximization (EM) algorithm is applied mainly for estimating the parameters of the models and reliability related quantities. For the Aircraft windshield failure data, results indicate that the method of estimation with the EM algorithm procedure is better than the Weibull Probability Paper (WPP) plot procedure. For Battery failure data, based on the measures of lifetime quantities, it can be concluded that data without maintenance information provides approximately similar results with the data having maintenance information. According to the graphical representation and estimated values of different model selection criterions, we found that the 3-fold Weibull-Normal-Exponential mixture model can be selected as the best model for the Hydraulic pump failure data. The selected distribution for pumps with assembly errors failure mode is Normal and the distribution for pumps without assembly error failure mode is Weibull. According to the optimization of the proposed objective function, the 3-fold Weibull mixture model gives a bit larger optimal maintenance period, however the Weibull-Normal-Exponential model shows a reduction in the maintenance cost for the pump. Simulation studies are conducted for investigation the performances of the proposed models and methods. The simulation results indicate that the proposed models and methods of estimation are applicable for analyzing 2-fold and 3-fold mixture models for censored product reliability data with incomplete information. The results presented in this thesis would be useful for managerial implications in assessing and predicting the reliability and maintenance cost of the products. Keywords: Product reliability, Data analysis, EM algorithm, Mixture model, Competing risk model, Simulation.
Climatic Change and its Impact on Wheat Production in Dinajpur District: Modeling and Quantitative Analysis
(University of Rajshahi, 2010) Afrose, Syeda Jahanara; Nasser, Mohammed
Dinajpur is the leading district for wheat cultivation in Bangladesh and wheat is much sensitive to climatic variation and change. An attempt has made to study the climatic change and its impact on wheat production in Dinajpur district and both the secondary and primary data are collected in this respect. The historical climatic data are collected for 1948-2004 which contain a missing of 8 years during I 973-1980. Primary data are collected by a sample survey to know the people's perception regarding change of climatic behavior on wheat production over the period. In this study, climatic trend and variability of Dinajpur district are examined for 19 climatic variables in decadal, annual, seasonal [three crop seasons like Rabi ={November-February), Prekharif =(March-May) and Kharif =(June-October)], monthly and wheat growing period using exploratory data analysis (EDA) tools such as boxplot, stem-and-leaf display, median polish table etc. Different robust and nonrobust measures are used and outliers are detected. Residual's stationarity is checked by Box-Pierce test statistic and normality is tested by RM (rescaled moment) test. Upward trend is found in means of monthly total rainfall and average cloud, relative humidity, relative humidity at mourning, relative humidity at evening, wet bulb temperature, wind speed, maximum wind speed and minimum temperature (slight) and downward trend is observed in their coefficient of variations (CVs). Both the variations and means for average difference of dry and wet bulb temperature, difference in mourning and evening relative humidity, evaporation and range temperature demonstrate downward trend. The monthly means of average maximum temperature and sunshine hour indicate downward trend and their CVs indicate upward trend. The average dry bulb temperature follows upward trend in Rabi and Kharif season and downward trend in Prekharif season. The average soil temperature at the depth of 5cm follows upward trend during 1987-2000 and sunshine hour show downward trend in all the three seasons during 1989-2004. The total rainfall shows upward trend in February, April, May, September, October and December but it does not show any trend in January, March, June, July, August and November. Time series properties of climatic (monthly data) and wheat production data are investigated from fitted ARlMA models based on minimum root mean square forecasting error of 24 and the values for 2005 to 2008 and 2009 to 2012 are forecasted from selected models. The missing values are forecasted by fitting ARIMA models. The year 1981 of the variables AMNT, A WBT, A WS, ARH and ARH(0-12) are detected as outlier in fitting the models during 1981- 2004 and the outliers are replaced by the forecasted observations from the data during 1982-2004. The square root transformed monthly data of total rainfall during 1948-2004 follow ARIMA (100) (111) model and the ADBT follow AR.IMA (011) (IO1). The production of wheat during 1949-2001 in Dinajpur district primarily follow upward linear trend and residuals are departed from normality but support non-autocorrelated structure and one outlier is identified in 1982 from the plot of deletion Studentized residuals. We have got an opposite conclusions from outlier corrected data. Structural change is observed in 1976 and the data for 1949 to 1975 and 1976 to 2001 separately follow AR (1) models but not for the overall period. The corrected data set during 1949-2001 adequately fits the 1st order Piecewise Autoregressive Model PAR (l) [suggested by lmon (2007)]. It may be mentioned that the reason for not considering the wheat production during 1948-2004 is that the data during that period do not adequately fit PAR (l) model. To quantify the impact of climatic change on wheat production during the period of 1948-2004 we have tried to fit a multiple regression model of wheat production data on climatic data (Nov-Mar) where one dummy variable is taken for the structural change in wheat production data in 1976. Multicollinearity among the predictor variables and normality and stationarity for the residuals are checked. Strong evidence is not found for multicollinearity and first order autocorrelated structure is found in the residuals. The parameters have been estimated using Cochrane-Orcutt iterative procedure where residuals follow normality and stationrity after removing two hi-leverages and two outliers and we observe no significant coefficient except dummy variable and this may be due to technological change such as high yielding variety, improved physical inputs like irrigation, fertilizer, pesticide etc. In the survey, hundred percent (100%) respondents have opined that there is a change in climate than previous time and the changing behavior of climate has severely affected the crop production, acreage under crop and the total process of production as a whole. Insufficient rain in Rainy season, lesser coldness in Winter season, lesser temperature in Summer and lesser dew in Autumn are experienced by them. Stormy and dusty wind does not blow as it blew before and cold affects people at night in the month of Choitra (mid March-mid April). Due to the unusual behavior of climate wheat production has suffered a lot. According to them, Changes of temperature are affecting the production of wheat greatly and they think those to be the most potential reasons. Changing of climate may pose a big and devastating threat to the production of wheat and 88% people opine that the cultivation of wheat in future may fall under a serious threat.
Correlates of High-Risk and Low-Risk Childbearing Pattern in Bangladesh
(University of Rajshahi, 2004) Chowdhury, Md. Abdul Mazed; Abedin, Samad
Childbearing in human population can be classified as early, on-time and delayed in context of age of a woman or a group of women. While on-time childbearing involves less risk, both early and delayed childbearing involve high-risk also involves in having children in quick succession as well as in having children more than three or four. Thus, childbearing occurs early or late, in quick succession and at higher parity (more than 3 or 4) involves high-risk and beyond these have some low-risk. Admitting that every pregnancy expulsion involves risk -more or less. The present study is an attempt to analyse the childbearing pattern that are termed as high-risk and low-risk and try to isolate the factors that discriminate and affect significantly the high-risk and low-risk pattern in the context of age, parity and birth interval. Methodology The study uses 17 variables that include age of women, parity, birth interval, age at marriage, age at first birth, duration of conjugal life, surviving children, child loss experience, duration of breastfeeding, contraceptive use, spousal age difference, place of residence, religion of women, education of women, education of husband, women's working status and occupation of husband. Such data are available from the 1999-2000 Bangladesh Demographic and Health Survey (BOHS) implemented through a collaborative effect of the National Institute of Population Research and Training (NIPORT), Mitra and Associates, and ORC Macro (USA). Multi-stage random sampling was used to obtain the data. Data were obtained from all the administrative geographical divisions of Bangladesh. A total of 10,544 ever-married women aged 10-49 were interviewed to collect data concerning fertility levels, contraceptive, infant mortality levels to improve the lives of mothers and children. Aside from rates and ratios used in the analysis of data, the study uses x2-analysis to list the association between the attributes of risk of childbearing classified as high-risk and low-risk in terms of age, birth interval and parity and indicates socio-economic and demographic phenomena. The study further uses two sophisticated statistical techniques namely, discriminant and multivariate logistic regression analysis. Findings It is evident that childbearing performance varies greatly with differences in religion, education, residential status and so on. Majority of women (78 percent) are not currently working outside home. A considerable 70 percent of women live in rural area. About 43 percent of the study population has no formal education. The data shows that mean age at first marriage is 14.9 years while more than 50 percent were married before the age of 15 years and 80 percent of Bangladeshi women marry when they are still teenagers, which increases the likelihood of their having high-risk births in the absence of contraceptive use before the first birth. In most cases, the first birth occurs between ages 17 and 19, the median age at first birth is 17-18 for all women aged 20 and older. The results indicate that childbearing of adolescent mothers have on average, shorter birth interval (less than 24 months) than their adults counterparts. Nearly one in six children are born after a "too short" interval (less than 24 months). Although, the median birth interval is 39 months, younger women have shorter birth intervals than older women. The median birth interval for women age 15-19 is 27 months, compared with 48 months for women over age 40. The mean number of children ever born to currently married women is 3.13, while it is 2.58 for all women aged 15-49. It was found that the variables viz., education of women, contraceptive use, women's working status, occupation of husband, duration of conjugal life, child loss experience, age at first marriage, age at first birth, duration of breastfeeding and surviving children are the most significantly associated corresponding to age, parity and birth interval. The variables that significantly discriminate the high-risk childbearing from the low-risk childbearing are age at first marriage, duration of conjugal life, age at first birth, contraceptive use, child loss experience, surviving children, education of women, place of residence, women's working status, spousal age difference, occupation of husband and duration of breastfeeding. It was also found that the most important significant variables that influence both the high-risk and the low-risk childbearing are age at marriage, place of residence, education of women, duration of conjugal life, child loss experience, age at first birth, working status of women, and duration of breastfeeding, contraceptive use and occupation of husband.
Covariates of Early Childbearing in Bangladesh
(University of Rajshahi, 2008) Islam, Md. Roshidul; Islam, Md. Nurul; Abedin, Samad
Early childbearing means the early growth that is the growth capacity of teen age’s women. It is apparent that early childbearing vary with varying demographic and socio-economic variables. Very little attention is given as to how to capture the pattern of early childbearing with respect to age, age at marriage, duration of marriage, children ever born as well with varying socio-economic situation like education of women, education of husband and working status of women and so on. Among the studies available, most of the focus on the consequence for developed countries. Since relatively lower attention has been given to one of the major influential factors of fertility decline in Bangladesh, the early childbearing. Early childbearing in human population is the achieved fertility of a woman or a group of women less than 20 years of age. While On-time childbearing involves less, both early and delayed childbearing involve high-risk also involves in having children in quick succession as well as in having children more than three or four. Thus childbearing occurs early or late, in quick succession and at higher parity (more than 3 or 4) involves high-risk and beyond these have some low-risk. Admitting that every pregnancy expulsion involves risk - more or less. The present study is an attempt to analyze the childbearing pattern that are termed as high-risk and low-risk and try to isolate the factors that discriminate and affect significantly the high-risk and low-risk pattern in the context of current age of women. Methodology The study uses 11 variables that include age of women, age at first marriage, duration of marriage, contraceptive use, place of residence, religion, education of women, education of husband, women's work status, occupation of husband and total children ever born. Such data are available from the 2004 Bangladesh Demographic and Health Survey (BDHS) implemented through a collaborative effect of the National Institute of Population Research and Training (NIPORT), Mitra and Associates, and ORC Macro (USA). Multi-stage random sampling was used to obtain the data. Data were obtained from all the administrative geographical divisions of Bangladesh. A total of 11440 ever-married women aged 10-49 were interviewed to collect data concerning fertility levels, contraceptive, infant mortality levels to improve the lives of mothers and children. There are 1703 ever-married women are eligible for our study ( <20 years) out of 11440. Aside from rates and ratio used in the analysis of data, the study uses x2-analysis to test the association between the attributes of risk of childbearing classified as high-risk and low-risk in terms of age indicates socioeconomic and demographic phenomena. The study also employed by two sophisticated statistical techniques namely, discriminant and logistic regression analysis. Findings It is evident that early childbearing performance vanes greatly with differences in religion, education residential status and so on. Majority of women (90.5 percent) are not currently working outside home. A considerable 70.8 percent of women live in rural area. About 28.1 percent of the study population has no formal education. About 65.6 percent women do not use contraceptive methods. It was found that the variables viz., education of women, contraceptive use, women's working status, occupation of husband, duration of marriage, age at first marriage are the most significantly associated. The variables that significantly discriminate the high-risk childbearing from the low-risk childbearing are marital duration, age at marriage, mother's education, place of residence, women's work status, religion and contraceptive use. It was also found that the most significant variables that influence both the high-risk and low-risk childbearing are marital duration, contraceptive use, mother's education, age at marriage, religion, place of residence and women work status.
Demand for a Child in Bangladesh: A Multivariate Statistical Analysis
(University of Rajshahi, 2004) Sarkar, Saroje Kumar; Mian, M. A. Basher
In Bangladesh, children especially sons are considered as an important part of standard of living as well as "poor man's capital". In this study an attempt is made to highlight some socioeconomic and demographic factors, which are affecting the demand for a child. Based on the findings, recommendations are given so that policy makers may take remedial measures to strengthen family planning program efforts, for accelerating the rate of fertility decline to achieve replacement level as early as possible. It is observed that for achieving the replacement level fertility, the family planning program should be strengthened among the ever-married women under age 30 due to the population momentum. The probability of demand for an additional child is significantly higher in Chittagong and Sylhet division than that in Rajshahi and Khulna division. Demand for an additional child is lower among working women than among housewives. The findings indicate that whenever gender preferences would be eliminated, the percentage of women who did not demand more children would be increased approximately by 10 percent. The findings also suggest that further increase in the contraceptive prevalence rates in the country may become increasingly more difficult unless there is a decline in the latent demand for male children. Therefore, we conclude that further reduction of fertility to achieve replacement level is unlikely without considerable reduction in the demand for male children and policy makers should emphasize those policies that actively enhance women's status through education as well as involving them in the workforce in the country and change attitudes towards girl children.
Demand for Universal Primary Education in Bangladesh: A case study of Jhenaidah District
(University of Rajshahi, 2014) Rahman, Md. Shahinur; Mian, M. A. Basher
The aims of this study is to search for ways and means for a school system at the primary level of education based on a curriculum and terminal competencies with an unanimous and conscience acceptability of the people in general without much disturbance to the present set up. Such a system may be termed as Universal Primary Education system. The right of education is recognized as a human right and is understood to establish an entitlement to education. It is one of the five basic rights. Education is classified into three broad classes: informal, non-formal and formal. This study belongs to the problem of prevailing multi-channel formal education at primary level in Bangladesh. The learners mainly educated by three different streams-General stream, Ebtedayee Madrassa stream and Kindergarten stream possess three kinds of knowledge. So their thoughts and ideas, plans and programs are not co-linear and they are not guided and led to the same line. Universal primary education, as is emphasized by different world bodies and organization is indicative of uniform or uni-channel one. Almost all the education commissions set by the Bangladesh Govt. the NGO’s and many individual researchers highlighted this problem and considered it as a barrier towards the implementation of universal primary education. But neither the Government nor any NGO’s taken any initiative or highlighted any way to solve this problem. General objective of the study is to see the socio-economic and educational attainment impacts of Demand for Universal Primary Education in Bangladesh. Though Bangladesh is a country of unique language-Bengali, here prevails a multi-channel education right from primary level which is against and hinders the spirit of universal primary education. This region including Bangladesh was ruled by many rulers with different religious faith. Brief history of the educational reforms in Bangladesh, as well as in the Indian sub-continent is discussed. This justifies the existence of a multi-channel education in a country of univocal language. Having the history scrutinized, we can say that primary education that we find today is not shaped in a day or two. This dissertation is an exploratory one and based on mainly primary data. The data was collected from the study area in two different phases to serve different objectives. At the first phase, data was collected two times from 523 respondents. In the second phase, two examinations were conducted on the students of class V. Two stage stratified PPS cluster sampling design for collecting data followed by analysis of data and the underlying tools and methodology used in inference procedure are discussed in brief. Twenty variables/covariates associated with the respondents including the demand for universal primary education have been studied of which nine has no association and nine has significant at p≤0.01 and one has p≤0.05 level of significance indicated by the calculated chi-square value with the demand for universal primary education. The cross relationship between social identity and year of schooling, basic education at primary level, land holding size, monthly family income, expenditure are highly associated. A stepwise logistic regression shows that associated variables to affect the demand for universal primary education. Younger people in comparison to aged, smaller land holding size in comparison to larger land holding size and alternative demand to General and Madrassa education in comparison to Kindergarten highly demand the Universal Primary Education. The logistic regression model is observed to be well fit as is indicated by LR statistic = 222.588. Cox and Snell R^2=0.593, Negelkerke R ̅^2= 0.808 and Model χ^2=470.294. It is observed that when the value of R ̅^2 exceeds 0.5 that data fit binary logistic regression model fit. So the model can be used for the significant prediction about the demand for a universal primary education in Bangladesh. The ratio regression model produced a good result with R^2=0.9818 and adjusted R ̅^2=0.9492. Results of logit regression analysis are left out because, logit transformation of demand proportions yield a large number of indeterminate out puts making the analysis useless. Two surveys were conducted with changed order of terminal competencies at each survey among the dissimilar (76-28) =48 of the three different streams. The Pearson frequency correlation =0.533 and rank correlation =0.511 that the correlation is significant at the 0.01 level. So, survey result is reliable. There is no hard and first rule for selecting the 30 terminal competencies out of 48. We have proposed five arbitrary rules (Test-Re-Test method) in order to eliminate the 30 (maximum) out of 48 dissimilar terminal competencies among the streams. Spearman rank correlation 0.911 and Pearson correlation coefficient 0.909 are in close agreement indicating the high reliability of survey results selected under rule-IV. To test the validity of rule IV, two set of questions are prepared. One set comprised of original terminal competencies of each stream. Another set with the newly selected 30, in addition to common 28 for all the streams. Correlation (Pearson) coefficient of marks in the two separate examinations considered as measure of validity of the terminal competencies obtained by rule IV for streams separately and for the total system. Correlation between the scores of two examinations is observed to be highly consistent and nearly constant, justifying the validity of the proposed model. Hence, the set of terminal competencies selected under rule-IV along with existing common 28 in total (28+30) = 58 terminal competencies may be recommended as reliable and valid terminal competencies for the uniform and universal primary education in Bangladesh. To develop a measure of efficiency for education system based on academic performance of students. Advantage of the proposed measure is that it can be used at each and every situation, for individual school to national level, for sub system to aggregate system and for uniform and multi-channel education systems. Efficiency of the existing multi-channel primary education is compared with a proposed uniform and universal primary education in Bangladesh by using the proposed measure. Results obtained are observed to be useful and encouraging. Proposed universal system may be run experimentally in some of the schools and results of those schools may be compared with existing multi-channel schools for relative efficiency of the universal primary education.
Demography of Aging : Lessons from Bangladesh
(University of Rajshahi, 2001) Hossain, Md. Ripter
The aging of population is thought to be the outcome of interplay between fertility and mortality. So is the case with Bangladesh. In the face of socio-economic transformations that are taking place in Bangladesh, it is assumed that the demographic transition what has been underway in the country in recent years affects the upper age spectrum of the population and has resulted in increase of the older persons of age 60 and over. However, the demographic consequences of changing population age structure and the growing number of older persons are yet to fully understood. The present study is an attempt to explore the causes and consequences of population aging in Bangladesh. The aim of the study is to explore the current situation and future trend of population aging under the changing condition of demographic variables, specifically, fertility and mortality. The objectives of the study are: ■ to look at the change in the level and pattern of fertility and mortality and their effect on the age structure of the population, ■ to examine the impact of undergoing demographic transition on aging of population, ■ to investigate the current age-sex structure of the aged population and to asses future trend under various demographic alternatives and ■ to understand the consequences of population aging in the country. The study has been based on secondary sources of data. The secondary data have been taken from different published and unpublished sources. These are Vital Registration, Population Census, Demographic Survey of East Pakistan, Population Growth Estimation Experiment, National Impact Survey, Bangladesh Retrospective Survey on Fertility and Mortality, Bangladesh Fertility Survey, Bangladesh Contraceptive Prevalence Survey, Bangladesh Demographic and Health Survey, Demographic Surveillance System and some others. Besides these sources, data are also taken from United Nations publications. The study has been carried out on the basis of such demographic indicators as crude birth rate, crude death rate, total fertility rate, median age, age and sex composition, marital status, life expectancy, and so on. The study has analyzed the demographic transition caused by reduction in fertility and mortality and also identify the factors affecting the aged population. To estimate and project the aged population, the models viz. Exponential growth model, Modified exponential growth model, Geometric model, Makeham's model and Logistic model have been used. The study has estimated and projected mid-year female population of Bangladesh by age group during 1991-2021 and through applying Frejka's component method in Leslie matrix form. Finally, Cohort component method has been used to estimate and project the mid-year total population of Bangladesh by age group. The expected trend in aging of population of Bangladesh reveals a clear increasing level in aging population both in case of males and females. As regards age structure it is found that the elderly population( 60+) has increased by 1 percent during 1911 to 1991. The projected figure of elderly population in Bangladesh shows that the size of the elderly population is expected to increase from nearly 6.02 million in 1996 to 7.78 million in 2006. It is also evident that there is a consistent increase in the proportion of aged 60+ compared to the population in those of young and adult age groups. Thus older population of Bangladesh is going to increase remarkably between the next two decades from 2010 to 2030. The exponential growth rate of elderly population in Bangladesh is lower than the other Asian countries. With regard to demographic change the crude birth rate has reduced to as low as 25.6 percent in 1996 from 53.8 percent in 1901. The total fertility rate has also declined with narrow amplitude. It has reduced from 6.78 in 1961 to 3.41 in 1996. Comparison of crude birth rate with the proportion of aged population reveals an inverse relationship between the two. So is the case between the aged population and total fertility. With the decline of total fertility, the aged population would gradually increase. Crude death rate has also an uninterrupted declining trend over the period of the study. Reduction of mortality has however been the important factor in triggering off the rapid growth of population in Bangladesh. Again a considerable decline in infant mortality is noticed in the second half of the twentieth century. Infant mortality reduced to 67 deaths per 1000 live births in 1996 against 140 in 1960. As regards crude death rate and expectation of life at birth, there is a close relationship between the two variables. The average length of life has increased more than double in this century from 24 years in 1901 to 59 years in 1996. The relation of crude death rate with aged population reveals that about 77 percent variation in the proportion of aged population is explained by crude death rate. About 99 percent variation in such proportion is explained by expectation of life at birth. As regards to nuptiality, significant changes in marital composition and in the mean age at marriage are noticed. The mean age at marriage of females has increased to 20.1 years in 1996 as against 12.6 years in 1931 and for males to 27.8 years from 19.0 years during the same period. Both the factors are closely related to fertility thereby affect the aging of population. Estimate and projection of the aged population reveal that in next 20 years their number will exceed nearly one crore and in the mid of the next century the elderly( older persons) is expected to increase nearly 205 times than today. The aged population of Bangladesh will increase gradually up to 2021 and thereafter it will increase remarkably between 2021 to 2051 about 4.6 times by the end of 2051 from the figure of 1981. Thus, we have clear evidence that the aging of population that is taking place in the country can be accounted for the transition of both fertility and mortality i.e. the demographic transition vis-a-vis changes in the age structure. In view of growing number of elderly m Bangladesh, the aged population gradually emerges as a vulnerable group in our society. The well-being of the older person requires formulation of appropriate polices and programmes through a clear understanding of the problems, needs, and demands of this vulnerable group, their status and functions in the family and society, their living arrangement, support systems, economic activity, potentiality and so on. Population aging in Bangladesh is becoming a serious concern for the development agendas. The issue should be dealt with much care. The rapid rate of aging of population and the growing cohorts of older persons have particular implications for the development of the country including increasing economic dependency and rising incidence of care giving to older persons by the traditional social unit, the family. Maintenance of joint family system could be a policy option.
Determinants of Hypertension in Bangladesh: A Case Study of Rajshahi District
(University of Rajshahi, 2013) Ali, Md. Ayub; Mondal, Md. Nazrul Islam; Ali, Md. Ayub
Hypertension is a silent killer of human life and the numbers of hypertensive patients are increasing globally and nationally. Therefore, the purpose of the study was to investigate age-specific hypertension patterns, alarming age for hypertension, and many determinants of hypertension in Bangladesh, e.g., feminine and nuptial determinants, socio-demographic determinants, health complication determinants, and body composition determinants. The data were collected from Rajshahi district using stratified multistage sampling with technique based on the scheduled questionnaire for this study. To identify the most important determinants, sophisticated statistical tools have been used such as percentage distribution, point bi-serial correlation, phi correlation, Pearson product-moment correlation, path analysis, boot strapping technique, binary backward logistic regression method including Likelihood ratio test, Hosmer-lemeshow test, Nagelkerke R2, Sensitivity and specificity, receiver operating characteristics (ROC) curve etc. It was found that the number of systolic hypertensive patients (60.40%) were greater than diastolic hypertensive patients (47.90%) in old age group (≥61 years) where diastolic hypertensive patients (7.40%) were greater than systolic hypertensive patients (3.80%) in young age group (≤39 years) and in middle age group (40-60 years) both are same. Hence, young age (≤39 years) was risk period for occurring diastolic hypertension than systolic and old age (≥61years) was risk period for occurring systolic hypertension than diastolic when middle age (40-60 years) was also risk period for occurring both type of hypertension. The differences between two same percentiles of systolic and diastolic blood pressure were varying from 51 mmHg to 93 mmHg for hypertensive respondents where it is same for normotensive. Hence, the abnormality (>40 mmHg) of the differences is an indicator of hypertension or prehypertension. From the view of proper critical analysis of impact of some key factors on hypertension, the study was divided into four aspects such as socio-demographic, feminine and nuptial, health complication and body composition aspects. About 28.10% hypertensive patients were due to socio-demographic aspect. Applying binary logistic regression model in the study of causal relationship, age was found as the most significant variable. i. e. age had positive significant impact on hypertension. Secondly, education had second most significant negative impact on hypertension and its odds ratio focus that for every increase of one year in education, the risk of hypertension increased 0.958 time. It was also found that sedentary life style, working hour (>8 hrs) per day, social stress, occupational stress and mental stress, hereditary hypertension, smoking, taking alcohol and taking excess salt had positive significant impact on raising hypertension where taking regular exercise had negative significant impact on hypertension. Hence, sedentary life style, working hour (>8) per day, social stress, occupational stress, mental stress, hereditary hypertension, smoking, taking alcohol, taking excess salt may be considered as risk factors for raising high blood pressure or hypertension. Though the age was found to be as the highest risk factor, but age increasing is out of human control. In the health complication aspect, the adult hypertensive patients were 30.60%. In the analysis of causal relationship (applying binary backward logistic regression method) between hypertension and other health complication, kidney disease was found as a significant variable. i. e. kidney disease had positive significant impact on hypertension and its odds ratio 5.428 indicates that the respondents with kidney disease had 5.428 times risk to occur hypertension than the respondent without kidney disease. Also, tumor, diabetes, sleep apnea, hypothyroidism, hyperthyroidism, tachycardia and overweight had the positive significant impact for occurring hypertension. After discussing the binary logistic regression it was further found that kidney disease, tumor, diabetes, sleep apnea, hypothyroidism, hyperthyroidism, tachycardia and overweight might be considered as risk factors for raising high blood pressure or hypertension. In selected feminine and nuptial aspect, the active married female hypertensive patients were 28.90%. In the study of causal relationship (applying backward binary logistic regression model) between hypertension and other feminine and nuptial characteristics, first menstruation age was found to be as significant variable. i. e. first menstruation age had negative significant impact on hypertension. Duration of couple life had significant positive significant impact on hypertension. Use of contraceptive method, menopause, pregnancy and miscarriage had positive significant impact for occurring hypertension compared with those who do not possesses the characteristics. Hence, first menstruation age, duration of couple life, use of contraceptive method, menopause, pregnancy and miscarriage might be considered as risk factors or determinants for raising high blood pressure or hypertension. Using path analysis, the total effect of body mass index, abdominal circumference and ratio of waist to hip on systolic blood pressure were 0.207, 0.185 and 0.118 respectively in which their direct effect were respectively 0.146, 0.082 and 0.047. The total effect of body mass index, abdominal circumference and ratio of waist to hip on diastolic blood pressure were 0.289, 0.231 and 0.138 respectively in which their direct effect were respectively 0.231, 0.079 and 0.043.
Exploring Toxicogenomic Biomarkers using Statistical Models
(University of Rajshahi, 2019) Hasan, Mohammad Nazmol; Mollah, Md. Nurul Haque; Begum, Anjuman Ara; Rahman, Moizur
Toxicogenomics studies combines toxicology with several omics technologies (genornics, transcriptomics, proteomics and metabolomics) to assess the risk of toxins (small molecules, peptides or proteins) and chemical agents (drugs, gasoline, alcohol, pesticides, fuel oil and cosmetics) in organism. Through integration of these omics technologies with bioinformatics, toxicogenomics can be used to suggest the molecular mechanism of toxicity. This can reduce the cost in terms of time, labor, compound synthesis and animal use which are main limitations of traditional toxicology work. There are three main objectives of toxicogenomics studies as well as drug discovery and development. 1) To explore the toxicogenomic biomarkers and toxicity of the doses of chemical compounds (DCCs). 2) Exploration of co-clusters between correlated genes and DCCs. and 3) Detection of significant gene and DCCs interactions. In this thesis, we have addressed all of these objectives in absence and presence outlying observations in the toxicogenomic dataset. There are some online computational tools that can explore the toxicogenomic biomarker genes based on t-test and Mann-Whitney U test. However, these tools cannot identify the significant DCCs that regulate the expression pattern of biomarker genes. To overcome this problem we have described one-way ANOVA together with and tukeys' HSD test (post-hoc test) ( chapter 2) to explore toxicogenomic biomarker genes and the significant toxic DCCs. The biomarker genes identified by the ANOV A approach are functionally annotated and found statistically significant for the respective pathway. The tukeys' HSD test identified toxic DCCs have also been validated by the existing literature. Besides this, according to the characteristics of toxicogenomic data exploration of co-clusters between genes and DCCs is another important objective of toxicogenomic studies. Hierarchical clustering (HC) is very popular and widely applied data analysis tool; it search interesting groups of objects in a dataset based on any combination of distance (euclidean, maximum, manhattan, canberra, minkowski) and HC (ward.D, ward.D2, single, complete, average, mcquitty, median, centroid) methods. However, these distance or clustering methods do not perform equally in grouping objects for all types of dataset. Even the performance of some of these combinations is very poor in some specific field of study. In this thesis ( chapter 3) we have selected more suitable HC methods ward.D or ward.D2 in combination with distance methods euclidean, manhattan or minkowski for clustering genes and DCCs of toxicogenomic data. Furthermore, in chapter 3 we have proposed an algorithm for co-clustering between genes and DCCs based HC approach. Though the selected HC clustering approaches together with the proposed co-clustering algorithm can co-cluster the genes and DCCs, these approaches are very sensitive to outlying observations. Therefore, we robustify the selected HC approaches in chapter 4. We observed that the proposed robust HC (RHC) approaches outperform over the classical HC approaches. The gene-DCCs co-clustering results based on RHC using the co-clustering algorithm (proposed in chapter 3) have been validated by the existing literature. Nonetheless, the classical clustering approaches (e.g. k-means, fuzzy, HC, etc.) including our proposed RHC use one-way (gene or DCCs) information for clustering/coclustering. Thus, these clustering approaches is not flexible and effective for coclustering genes and DCCs. On the other hand, probabilistic hidden variable model (PHVM) uses two-way (gene and DCCs) information simultaneously for co-clustering between genes and DCCs. Therefore, this approach is more effective and suitable for coclustering. However, the PHVM approach is not robust against outliers. To overcome this limitation of PHVM in this research (chapter 5) we have proposed logistic PHVM called as LPHVM for robust co-clustering between genes and DCCs discover toxicogenomic biomarkers and their regulatory DCCs. We have observed that the proposed LPHVM approach perform better compare to PHVM and classical co-clustering approaches based on the results of the simulated and real data analysis. In order to answering toxicogenomic questions researchers are being suggested different suitable offline and online computational tools, since a single computational algorithm cannot always produce the answers of the toxicogenomic questions. This is because; large scale datasets have been generated by the complex toxicogenomic experiments. For example, the co-clustering approaches based on HC and hidden variable models sometimes cannot separate the significant up-regulatory (UpR) (the gene is up-regulated by the influence of the DCC) and down-regulatory (DnR) (the gene is down-regulated by the influence of the DCC) gene-DCC interactions from the equal-regulatory (EqR) (thereis no DCC effect on that gene) interactions within a co-cluster. On the other hand, separation of UpR and DnR gene-DCC interactions from the EqR interactions is the cornerstone in toxicogenomics studies as well as in drug discovery and development. Therefore, in chapter 6 we have proposed MRC and LMRC for the detection of significant gene-DCC interactions, so far of our knowledge which have not been considered yet in toxicogenomic studies as well as in drug discovery and development. However, LMRC produces robust results compare to MRC in presence of outlying observations in the data otherwise they perform equally.
Factors Affecting The Technical Efficiency Of Boro Rice Producers Of Northern Rigion In Bangladesh
(University of Rajshahi, Rajshahi, 2021) Kundu, Ranjan Kumar; Karmokar, Provash Kumar
Because of its significant contribution to the development of various economic-related activities and self-sufficiency in food production, agricultural production needs to increase under the existing challenges so far. Despite increased rice production, it is evident that among all varieties, Boro rice is contributing the largest share of Bangladesh as well. The satisfactory contribution in the production of Boro rice has been unearthed for the Northern regions of the country in this respect. As therefore, investigation of determinants of production risk and efficiency and /or inefficiency may have an important role based on the stochastic production framework. According to the objectives, an attempt has been made to examine the contributory impact of the assigned input variables using frontier modelling. Firm-level primary data of 350 Boro farmers have collected from Rangpur, Dinajpur, Bogura, and Natore districts using an appropriate sampling technique and choice of functional form, distributional assumptions of models. Together with different preliminary statistics related to the research, technical efficiency has computed using Stochastic Frontier Modelling for selected Upazilas and districts. Small unit efficiencies have been computed for the eight Upazilas. The Farmers' Performance Indicators on the integrated management in the efficiency ground has been investigated under the Half-Normal assumption of errors of districts as well as the pooled data.
Factors Associated with Target Fertility in Bangladesh
(University of Rajshahi, 2012) Karim, Md. Rezaul; Islam, Md. Nurul
In this study, an attempt has been made to assess the factors associated with target fertility in Bangladesh using nationally representative data from Bangladesh Demographic and Health Survey (BOHS), 2007. Simple linear regression as well as multivariate techniques named logistic regression analysis have been used to find out the direct, indirect and combined (interaction) effects of the selected socio-demographic factors on fertility. To quantify the proximate variables, we apply Bonga arts' model as well as proposed Bogart’s' model. The results of the study show that several socio-economic (socio-economic, demographic) variables effect on fertility behavior. These are age at marriage, place of residence, religion, region, education of women and men (partner's/husband's), working status of women, occupation of women and men (husband's), women's participation at NGO's, age at first birth of women, length of breastfeeding practice, contraceptive use, number of dead children (boys and girls) etc. Fertility is still high in Bangladesh, though it has been declining over time. A major cause of declining fertility has been the steady increase in contraceptive use over the last 32 years; another major cause of declining fertility has been the steady increase the age at marriage. Current contraceptive prevalence rate (CPR) is 56% in 2007 BOHS (Mitra et, al., May 2009). The effect of marriage pattern and marital fertility, on the overall fertility of Bangladesh examined by Coal’s indices show higher influences of marriage pattern than that of marital fertility. The effect of change of marriage pattern in reducing fertility level perhaps has increased over time. Again, the age pattern of marriage and the contraceptive use have changed in a positive direction, the negative impact of which has fallen on fertility. Examination of the changes of the indicated indices at various time segments that the changed could be a recent phenomenon. To identify the change of fertility in terms of proximate variables, Bonga art’s model has been used. Among the variables in the analysis of proximate determinants of fertility happened to be in response of the effect of increase in proportion married and contraceptive use. These determinant shows that 5.69% decline due to change in the proportion of women married, 12.36% decline due to contraceptive use, 0.596% decline due to increase the index of fetal wastages and approximately 20.38% increase due to decrease of the duration of lactational in fecundability. Application of Bonga arts · model indicates that there is a downward trend in all the proximate indices. Between 1997 and 2007 the amount of decrement of total fertility rate is about 17.51 % and it is about 10.139% between 2004 and 2007. This is primarily caused by an increase in the use and effectiveness of contraceptives. The divorce and widowhood have also a major contribution on reduction of the fertility in Bangladesh. Observed TFR found to be 2.7 in 2007 and Bonga arts' model estimate the TFR is 3.21 which is far away from observed TFR but our proposed model estimates the TFR is 2. 76 which is closer to the observed TFR. Again, for consideration only abortion index in Bonga arts · model the estimated TF is 12.83 which is far away from assumed TF and our proposed model gives the value of TF is 14.99 which is very close to observed TF (15.3). So, comparing the estimated values we conclude that proposed model is better than Bonga arts· model. The study of differential fertility indicates the inverse relationship between age at marriage and fertility; education of women, men (husbands) and fertility; occupation of women, men (husbands) and fertility. We observed that fertility is higher in rural areas. There are several reasons, these include may be the rural women are less educated than urban women; rural women have poor media connection etc. Regional difference reveals that fertility is higher in Chittagong, Sylhet and Barisal than from Khulna, Rajshahi and Dhaka division. Dhaka and Rajshahi division have intermediate levels of fertility. Religion has effect on fertility behavior through Muslims and Non-Muslims. The analysis shows that fertility among Muslims is higher as compared with non-Muslims in each age group. Several variables, such as, work status of women, women's participation at NGO's suggests that labor force participation may be consequence of lower fertility than non-working counterpart. Women who are involved, with any service are not dependent on men (husbands), both socially and mentally have their own rights and absence of dependence, men cannot forcibly use women to increase their fertility. This has resulted in lower fertility. Results of logistic regression analysis indicates that place of residence, religion, age at marriage of women, age of first birth of women, women's education, contraceptive use, women's currently working status, pregnancy status, number of living children, access of mass media and involvement in NGO's are ttie most important significant variables that influence fertility in Bangladesh. According to the regression, the TFR equals, on average 7.742 births per women in the absences of contraception (CPR=0), and fertility declines at a rate of approximately 1.0 birth per women for each 9% increment in the contraceptive prevalence rate. The regression equation of TFR on CPR suggests that a TFR of 2.4 births per women can be achieved if the level of CPR will be raised to 61 % and if the level of CPR will be raised to 65% it is possible to achieve a target TFR level of 2.1 births per women. The prevalence rates are computed at the effectiveness levels of 0.85 and 0.90 such effectiveness of contraception has already reached 0.85 in the year 2007. The results indicate that if target fertility 2.6 is to be achieved then the CPR will be raised to 58% and 57% with 0.85 and 0.90 effectiveness respectively. Similarly, if target fertility 2.1 can be achieved the CPR is to be approximately 68% and 66% with 0.85 and 0.90 effectiveness respectively. The result also found that to reach the desired level of target fertility it must increase the use of contraception, duration of breastfeeding, singulate mean age at marriage and amenorrhea period. To achieve replacement level of fertility at 2.1 births per women we should increase the CPR, SMAM, duration of breastfeeding and amenorrhea period by 68%, 20.80 years, 15.5 months and 22.56 months respectively.
Impact of Early Childbearing on the Health of the Mother and Child: A Statistical Study
(University of Rajshahi, 2013) Islam, Md. Ashraful; Islam, Md. Nurul; Hossain, Md. Golam
Recent research has document the focus of rapidly growing interest on adolescents’ and their child health in the developing and under developed countries because of its important implications not only for the health of mother but also their children. Early childbearing is an important indicator for women’s and their child health. Body mass index is an indicator of nutritional status in a population. This indicator provides the circumstances that can assist intervention to help eradicate many preventable diseases. Health impact of teenage childbearing is not only due to socio-demographic factors but also due to biological factors. Women early age at first marriage were associated with early childbearing and early childbearing is considered as a risk factor for poor prenatal outcomes. There is a need to study demographic trends particularly trends in marriage under the framework of “basic need strategy”. The objectives of “basic need strategy” among others are to eradicate poverty, unemployment, hunger and literacy is considered as a major precondition for achieving population goals and the participation of women in development. The main objective of this study is to evaluate and analyze the impact of early childbearing on the mother and their child health of rural and urban community in Bangladesh. The specific objectives were: first one, to find the effect of socio-demographic factors on early childbearing mother’s health; second one, to investigate the changes in age at first marriage of Bangladeshi women over time and third one, to estimate the parameters involving in the age patterns of marriage and evaluate the patterns (using single year age distributions) of distributions of first marriage frequencies and risks of the first marriages of ever married women in Bangladesh. Finally, the purposes of the study were to demonstrate the applicability of the generalized Poisson regression (GPR) model as an alternative of other statistical methods and to find some predictors of child malnutrition in Bangladesh. Considering the reproductive women (age 15-49 years), data was extracted from Bangladesh Demographic and Health Survey in this study. For measuring mothers’ health a sample of 1908 ever-married women of age 10-24 were used from the total sample of 10,966. For investigate the age at first marriage and its trends over time, data for 47,109 married Bangladeshi women from 1944-1985 were analyzed. To estimate the parameters of Coale’s nuptiality model and evaluate the patterns of distributions of first marriage frequencies also risks of the first marriages of ever married women in Bangladesh, eventually all of 10,996 ever married women from age 15 to 49 years were taken. To examine the health problem and risks faced by early childbearing mothers’ children in Bangladesh a total sample of 3,207 were extracted. Logistic regression was used to examine the relative importance of socio-demographic factors on early childbearing mothers’ health. ANOVA and linear regression analysis were used to investigate the changes in age at first marriage of Bangladeshi women over four decades. The first marriage frequency and risk of first marriage of women was estimated by Coale and McNeil (1972) model. This model considered five year age group of population. In the present study single year age distribution of ever married female in Bangladesh has been considered. Finally for measuring child health Chi-square test and GPR model were used. More than 33 percent early childbearing mothers have been suffering from chronic energy deficiency, among them 35.4 percent came from rural and 26.9 percent from urban. The BMI varied from 11.95 kg/m2 to 37.79 kg/m2, with a mean of 19.86 ± 2.70 kg/m2 (95% CI: 19.74-19.98). About 15.7 percent women fall below the cutoff of 145 centimeters in height. A decreasing trend was found in the number of CED women with increasing educational level. Student t-test revealed that caesarean mother had a higher BMI than non-caesarean mother (p < 0.001. The coefficients and odds ratio of logistic regression analysis demonstrated that early childbearing mothers who were from rural areas, illiterate, hard laborer, unemployed partner, poorest, non-caesarian, delivered at home, earlier age at first marriage, early age at first birth, having two or more children, were at higher risk for getting chronic energy deficiency (underweight). Based on Wald statistics (16.258) we conclude that age at first marriage was the most influential variable on early childbearing and undernourished mother in Bangladesh. The mean and median age at first marriage of ever married Bangladeshi women was 14.73 ±2.96 years and 14.00 years, respectively; rural women got marriage significantly (p<0.01) earlier than urban women. More than 85 percent (rural 87.6 percent and urban 78.2 percent) Bangladeshi women got marriage before they reached 18 years old, among them 17.0 percent (rural 18.5 percent and urban 13.1 percent) got marriage very early age (before 13 years old). The present study demonstrated that the age at first marriage of ever married Bangladeshi women was showing increasing tendency with changing time. Using ANOVA, age at first marriage for rural and urban showed significant (p<0.01) differences among the birth year cohorts from 1944 to 1985 of the present sample. However, the slope of linear regression line indicated that age at first marriage for both rural and urban women exhibited increasing tendency during the investigated period. Also, the present study demonstrated that the child marriage among Bangladeshi women showed slightly decreasing tendency during birth year cohorts from 1944 to 1985. Coale’s model was used to find the age pattern of marriage among Bangladeshi women. The model gave us interesting results. Most of female got married before the age of 20 years with almost 100 percent getting married by the time they reach age 30. In Bangladesh the legal age of marriage is 18 years old for the women; however a large proportion (about 95 percent) of marriages below this age still take place. The GPR model has been found to be reasonable to study the outcome variable because of its under-dispersion (variance < mean) property. Our study also identify several significant predictors of the outcome variable namely; region, place of residence, father’s and mother’s education, mothers occupation, wealth index, delivery system, place of delivery, source of drinking water of the household, toilet facility, and total number of children ever born to a woman. These above results suggest that for improving health status of Bangladeshi early childbearing mothers, are need to improve the literacy. The result also suggest that age at first marriage of Bangladeshi women has been increasing for last four decades, and increasing rate of urban women is faster than rural women. Moreover, the study confirms that marriage still remains a universal phenomenon among females in Bangladesh. Early marriage prevails that marriage not only start early but progresses fast and are concentrated within a short span of time at least in the female population. Consistencies of our findings we suggest that the GPR model is an ideal alternative of other statistical models for analyzing child malnutrition in a family.
Impact of Socio-Economic and Demographic Variables on Human Fertility Behaviour-A Multivariate Statistical Analysis
(University of Rajshahi, 2009) Mahmud, Md. Nasim; Hossain, Md. Golam
The purpose of this study is to explore the possibility of further fertility decline in Bangladesh, with special attention to the role that might be played by improvements in socio-economic and demographic variables. In particular, researcher has attempted to estimate that after how long, and under what conditions, fertility rate should be taken for Bangladesh to reach replacementlevel fertility (2.1 children per woman). The medium-variant scenario of the United Nations projection indicates that Bangladesh will achieve replacement-level fertility around 2025-2030 (United Nations, 1999, 2001 ). Researcher assess whether the analysis yields a similar conclusion. The rapid decline of fertility, from over 6.5 births per woman to 3.3 births, in the last two decades in Bangladesh is, indeed, a historic record in demographic transition. The country is poor and has remained traditional and conservative. Although the extent and rapidity of the decrease in fertility have been very impressive by international standards, continued fertility decline is desirable, as population crowding, environmental deterioration, massive migration from rural areas to unplanned urban settings, and rapid depletion of resources are becoming acute. However, recent statistics suggest that, despite a continuing increase in contraceptive use, the fertility decline in Bangladesh has been stalled. The present study covers a period of about 30 years, from 1975 to 2004. The study is based on the analysis of secondary data sources mainly obtained from 1993-1994, 1996-1997, 1999-2000 and 2004 Bangladesh Demographic and Health Surveys (BDHSs) and 1975 and 1989 Bangladesh Fertility Surveys (BFSs). The time series data has been taken from the Bangladesh Bureau of Statistics (BBS) from 1985 to 2005, although the number of time series data is small, the annual data of Bangladesh for population studies are limited. In addition, data from the 1981, 1986 and 1991 Bangladesh Contraceptive Prevalence Surveys (CPSs) are also utilized. The samples of these surveys are nationally representative in scope and contain socio-economic and demographic information of individuals. Analyzing these data researcher has tried to focus on the past, present and future fertility situation of Bangladesh in connection with socio-economic and demographic variables based on several multivariate statistical analyses namely, logistic regression model, path model, Bongaarts' proximate determinants of fertility model and time series. It is found from the logistic regression model that the age at marriage, educational level, region, mass media, contraceptive method and child mortality are most influential variables on human fertility behaviour. It suggests that socioeconomic development policies as educational level, region, mass media and demographic indicators as age at first marriage, contraceptive method and child mortality giving special emphasis may produce significant desired effects with regard to fertility control in the national level of Bangladesh. The path analysis reveals that there are regional variations in fertility among the six administration divisions of Bangladesh due to some particular socio-economic and demographic variables. It demonstrates while one of the strategies to reduce fertility should be bringing down the desired family size, other strategies to narrow the gap of the regional variations should include efforts to increase education for female to reduce the preference for male children and to lower infant and child mortality, as well as to promote the effective use of contraceptives. Without a rapid improvement of these factors, it would be difficult to achieve replacement level fertility in near future. Bongaarts' model is applied to estimate the fertility inhibiting effect of four important proximate determinants: marriage, contraception, abortion and lactational infecundability. The model clearly indicates that there is a downward trend in all the proximate indices. Data on induced abortion are not available. So, its effect on the model is about to be immeasurable. Abortion is a sensitive issue in Bangladesh, and many women who have an abortion do not disclose this to others, particularly to outsiders. This makes the situation extremely difficult to get a clear picture of abortion from survey data in this country. Bongaarts' model indicates marriage variable made significant contributions to the overall fertility reduction. Contraceptive use has the highest impact on the total reduction of fertility which may be attributed to the increasing use of contraception from 7% in 1975 to 48.5% in 2004. The average estimated effect of lactational infecundability plays an important role in reducing fertility in Bangladesh. The analysis also shows that a downward effect on fertility at young ages caused by rising age at marriage has been balanced by an upwards effect at older ages caused by decreasing widowhood and divorced. Researcher suggests from the Bongaarts' model that the governmental policies can concentrate on effectively and efficiently increasing contraceptive utilization and effectiveness, on encouraging breastfeeding and on rising the age of marriage. One of the most interesting parts of this study that the researcher has developed a time series model to estimate after how long and under what conditions Bangladesh will achieve the replacement level of fertility (2.1 children per woman). Research has compared the time frame to reach the replacement level of fertility with the medium-variant scenario of the United Nations projection that Bangladesh will achieve replacement level of fertility around 2025-30 (UN, 1999, 2001 ). The research has found the similar result to reach the fertility rate of Bangladesh at the replacement level as the United Nations target year. Researcher has suggested that the total fertility rate (TFR) of Bangladesh will reach at the replacement level within the desired time period around 2025-2030 and to do so the government shall have to take necessary action- to increase mean age at marriage of female to be 20.3 years; to increase labor force participation of female to be 43.5%; and to decrease infant mortality rate per 1000 live births at 35.6. Lastly, it is shown from the study that the fertility rate has remained almost same in the national level of Bangladesh for a long time. But it is also found from the study that fertility rate has reached near to the replacement level in the few divisions of Bangladesh. It is really a matter of hope for us. Being greatly encouraged. Researcher would like to suggest that the regional key measures, responsible for achieving the replacement level of fertility rate must be found out, analyzed and researched and finally applied in other divisions of the country. By doing these, we can reach to our goal to the replacement level of fertility
Modeling and Predicting Prevalence of Tobacco Use in Bangladesh
(University of Rajshahi, 2018) Begum, Munjila; Sultana, Mst. Papia
Tobacco consumption is one of the major preventable causes of death and disability globally. Bangladesh is one of the largest tobacco consuming countries in the world. The use of tobacco is high among male population in Bangladesh. Also the use of tobacco is increasing. Therefore this study aims to explore the prevalence, patterns and determinants of tobacco use among adults. This study used data from Global Adult Tobacco Survey (GATS), 2010 that covered 9,629 Bangladeshi aged 15 years or above. The survey was based on a three-stage stratified cluster sample of household. Information of a total of 9629 adults has been analyzed in the present study. Pattern and prevalence of tobacco consumption in Bangladesh are primarily presented in the form of frequency distributions and in prevalence rates. This study uses binary logistic regression model and multilevel logistic regression model for analyzing data to quantify the objectives of the study. Prevalence of adults tobacco user was 44.05% in Bangladesh with 65.11% in male and 34.89% in female. Common significant predictors include sex, age, educational level and wealth Index. Male and older had a higher tendency to use tobacco products. Current tobacco smoking was significantly higher among male (p-value<0.001 and OR=44.17) than female. Females were more likely to use smokeless tobacco than males (odds ratio, OR=1.72). Adults with no education were more likely to use tobacco products in Bangladesh compared to others with tertiary education. Adults with the poorest wealth status were more likely to consume tobacco products in Bangladesh compared to those from richest wealth index. It applies a multilevel (two level) logistic regression analysis to draw valid conclusions about the effects of the selected determinants on tobacco consumption using GATS-2010 data which is a multistage stratified cluster data. Instead of single level logistic model, multilevel logistic regression model has been utilized since the data follow a hierarchical structure. Also the comparison between single and multilevel model has been done to investigate the necessity of multilevel effects. The findings suggest that sex, age, level of education and wealth index have significant multilevel effects on tobacco consumption. Manufactured cigarettes and betel quid with zarda are the most usable tobacco products in Bangladesh. Intervention to reduce or stop tobacco using should be directed towards the poor, older and people with lower education and women should be targeted for prevention of the use of tobacco. All the significant variables should be considered for developing suitable policies to reduce the consequences of tobacco use in Bangladesh.
Modeling of the Women’s Reproductive Behavior and Predicted Probabilities of Contraceptive Use in Bangladesh
(University of Rajshahi, 2016) Islam, Md. Rashedul; Islam, Md. Nurul; Rahman, Md. Monsur
Bangladesh is the most densely and is the 8th most populated country in the world. Over population or high density is one of the most important causes for both low and deteriorating living condition in Bangladesh Population is still growing. So, the situation is worsening with every passing year. Begging fully aware of the detritus effect of such rapid growths, the government, demographers, social workers, academicians, donor agencies and policy makers have declared population a problem of great importance and identified it as the number one problem in the agenda of governmental duties and functions. Like many other developing countries Bangladesh emphasizes the importance of contraceptive use for reducing fertility as a part of her overall strategy to bring down the growth rate of total population. Family planning programs work in order to achieve demographic targets through the reduction of fertility. Unfortunately, in our country there has always been a gap between target fertility and it’s getting at the terminal year of target period of all its plan period. Our country never gained either desired level of fertility (TFR) or contraceptive prevalence rate (CPR). The fifth Five-Year Plan (1998-2003), where target TFR and CPR respectively had 2.5 and 60%. Whereas, the achievement had been TFR 3.0 children per woman and CPR had been 58%. It was followed by the second Sector-Wide Approach, the Health, Nutrition and Population Sector Program, which began in 2003 and expired in June 2011, where target TFR and CPR respectively had 2.1 and 65%. Whereas, the achievement had been TFR 2.3 children per woman and CPR had been 61%. Additionally, the Health Population Nutrition Sector Development Program plans to reduce the TFR to 2.0 children per woman by 2016. To fulfillment such gaps there have raised questions about estimation equation used to project about CPR or contraceptive use effectiveness (UEC) in order to achieve TFR per woman at a desired level at the end of plan period or future. Thus in this study, an attempt has been made to assess the modeling of the women’s reproductive behavior and predicted probabilities of contraceptive use in Bangladesh using nationally representative data from Bangladesh Demographic and Health Survey (BDHS), 2011. To improve our clear understanding of the fertility change, we critically examine the effect of major proximate determinants on fertility and their changing effects for the period 1975 to 2011. During these periods decomposing Original Bongaarts Model (OBM) and Revised Bongaarts Model (RBM) assesses the individual contribution made by each of the four intermediate variables to change the fertility. The study also examines how well these determinants predict fertility levels of Bangladesh. Path model and binary logistic regression model have been used to find out the direct, indirect and combined (interaction) effects of the selected demographic, socio-economic factors on fertility. To achieve target fertility related with contraceptive prevalence rate (CPR) and contraceptive use effectiveness (UEC) four models viz., RBM and exponential regression model (ERM), polynomial regression model (PRM), linear regression model (LRM) have been applied. Revised Bongaarts model indicates that between 1989 and 2011, the amount of decrement of total fertility rate (TFR) was about 38.4%, about 42% between 1989 and 2007, 36% between 1989 and 2004, about 34% between 1989 and 1999-2000, 10% between 2004 and 2007; but the amount of increment of TFR was 6.6% between 2007 and 2011. The exogenous variables de-facto place of residence, current age of women, husband current age, education of women, wealth index have respectively 89%, 81%, 85%, 74%, 83% indirect effect on fertility. The endogenous variables women age at first marriage and women age at first birth have respectively 67% and 95%, other three endogenous variables sons who have died, women currently working and ever use contraception each has approximately 100% direct effect on fertility.
Modelling of Nutritional Status of Ever-Married Women in Bangladesh
(University of Rajshahi, 2015) Kamruzzaman, Md.; Hossain, Md. Golam; Islam, Md. Nurul; Abedin, Samad
The change in nutritional status plays an important role in the course of a person’s health. Body mass index (BMI) is measure of body fat based on height and weight of a person and it is used to screen for weight categories that may lead to health problems. The first main objective of this thesis was to observe the presence of secular trends in nutritional status of Bangladeshi married women over time. A total of 45,572 Bangladeshi non-pregnant married women in reproductive age were used in this study with average age 30.11±9.04 years. The secondary cross-sectional data used in this study was extracted from Bangladesh Demographic and Health Survey (BDHS) and they collected data from Bangladeshi ever-married women using multistage stratified cluster sampling. The last five rounds (1996-97, 1999-2000, 2004, 2007 and 2011) BDHS measured height and weight from their selected sample, the data was derived from the measurement years 1996-97 to 2011. Descriptive statistics, Analysis of variance (ANOVA) and linear regression analysis were used in this study. The mean value of BMI of Bangladeshi non-pregnant married women was 20.65±3.67 kg/m2 with height and weight were 150.60±5.44 cm and 46.93±9.24 kg, respectively. Using ANOVA, height, weight and BMI showed significant (p<0.001) differences among the measurement year cohorts from 1996-97 to 2011. The increasing tendency in height, weight and BMI of Bangladeshi married women in reproductive age were showed during the measurement years from 1996-97 to 2011. The sample was divided into 40 groups according their birth year cohorts from 1955 to 1995. ANOVA also demonstrated that the variation of height, weight and BMI were significant (p<0.001) among the birth year cohorts from 1955 to 1995. The slope of linear regression demonstrated that an increasing tendency in BMI was found among birth year cohorts from 1955 to 1971, but a decreasing tendency was observed during the birth year cohorts from 1972 to 1995. In this study found that more than 50% women were normal weight and a remarkable number of married women (31.4%) were underweight. More than 10% women were overweight and only 2.1% were obese among non-pregnant Bangladeshi married women. It was found that the proportion of underweight women has been increasing and the opposite direction also observed for the number of obese in those born during the last 40 years of the study period (1955 to 1995). Underweight can be considered as the major health problems of Bangladeshi married women and requires attention. The second objective of the thesis was to investigate the influencing factors of body mass index among Bangladeshi married women. Hierarchy data was used in this study that was collected by Bangladesh Demographic and Health Survey-2011 (BDHS-2011) using multistage stratified cluster sampling. Usually, large-scale survey for public health, demography and sociology follow a hierarchical data structure as the surveys are based on multistage stratified cluster sampling. The appropriate approach to analyzing such survey data is therefore based on nested sources of variability which come from different levels of the hierarchy. The single level statistical model is not appropriate for analyzing such kind of data set. Multilevel (two level) linear regression was utilized in the present study to remove the cluster effect for each outcome. The mean BMI of Bangladeshi married women in reproductive age was 21.60±3.86 kg/m2 with height and weight was 150.92 ±5.36 cm and 49.28 ± 9.69 kg, respectively. The prevalence of underweight, normal weight, overweight and obese were 22.8%, 59.1%, 14.9% and 3.2%, respectively of Bangladeshi non-pregnant married women in reproductive age for BDHS-2011 data set. Analysis of variance (ANOVA) demonstrated that the BMI of Bangladeshi non-pregnant married women in reproductive age was significantly different among respondents’ and her husbands’ education level (p<0.001) and wealth index (p<0.001). The t-test showed that the differences of BMI was significant between (i) urban and rural (p<0.001), (ii) watching television, yes and no ((p<0.001), (iii) currently breastfeeding, yes and no (p<0.001), (iv) currently use contraceptive, yes and no (p<0.05), (v) living with husband, yes and no (p<0.01) and (v) currently working status (p<0.05). Person’s correlation coefficients exhibited that respondent’s age, age at first marriage and age at first birth were significantly (p<0.001) positively related with BMI of married women in reproductive age, and there was a negative association between number of ever born children and BMI (p<0.001). Two level regression model demonstrated that age and age at first marriage of women were positively (p<0.01) related with their BMI. Parity was negatively related with women’s BMI. BMI was especially less pronounced among non-pregnant married women who came from rural, uneducated, uneducated husband, came from poor family, house wife, currently not use contraceptive and currently not breastfeeding. Under-nutrition is considered as a major health problems in Bangladesh especially of married women. Government and non-government organization of Bangladesh should take step to increase people education level and improve economic condition for removing under-nutrition among married women. The third and final main objective of this thesis was to quantify the prevalence of anemia and assessed how various nutritional, socio-economic and demographic factors associated with anemia among non-pregnant women in Bangladesh. Anemia is one of the most common and global public health problems. Highly prevalence of anemia was found among women of reproductive age in the world especially in developing countries. Study on anemia among Bangladeshi non-pregnant married women is poorly documented. Cross-sectional data were used in this study. Data was extracted from Bangladesh Demographic and Health Survey (BDHS) 2011. The nationally representative sample (5,293 married women) was selected by multistage stratified cluster sampling and data was collected from July 8, 2011 to December 27, 2011. Multilevel (two level) logistic regression analysis was done in this study. The prevalence of anemia among Bangladeshi married women was more than 41% and among anemic women, 35.5% was mild, 5.6% and only 0.2% were moderate and severe anemic respectively. Chi-square (χ2-test) test was utilized in this study for selecting independent factors for multilevel logistic regression analysis. χ2-test demonstrated that residence (p<0.001), respondents’ and her husbands’ education levels (p<0.001), currently breastfeeding (p<0.001), currently amenorrhea (p<0.001), currently use contraceptive (p<0.001), toilet facility (p<0.01), religion (p<0.001), wealth index (p<0.001), BMI (p<0.001), age group (p<0.001), number of ever born children (p<0.001) were significantly associated with anemia. The two level logistic regression model demonstrated that women who were currently breastfeeding and amenorrhea had more likely (p<0.01) to get anemia than their counterparts. Underweight women had a higher chance (p<0.01) to get anemia than normal weight, overweight and obese. Uneducated women were more likely to get anemia (p<0.01) than secondary and higher educated. Anemia was especially less pronounced among non-pregnant women who are currently use contraceptive (p<0.05), Muslim (p<0.01) and came from rich family (p<0.01). Moreover, women who were 30-49 years old had more likely to get anemia than younger (p<0.01). Under-nutrition is most important predictor for anemia among Bangladeshi married women and undernourished women are living under poor condition. Government of Bangladesh should take appropriate initiative to improve economic condition for removing anemia among married women.
Prediction of Adult Stature of Japanese Boys and Girls
(University of Rajshahi, 2003) Rahman, J.A.M. Shoquilur; Ali, Md. Ayub
The longitudinal growth of individual's stature of the present study was characterized from early childhood to adulthood. The samples used here were 509 males and 311 females. A triphasic generalized logistic model (BTT model) and diphasic growth model (JPA-2 model) applied respectively on the above two sets of data through the software AUXAL for characterizing individual growth of stature. The default values of the population mean and covariance matrix in AUXAL for both the models were substituted by estimated population mean and covariance matrix based on Japanese population. The individuals without mid growth spurt for both sexes show that predicted adult stature (PAS) was significantly positive correlated with stature at onset of adolescent and adolescent growth phases, and for only girls VTO and PHV was positively correlated. The individuals with mid growth spurt for both sexes show that PAS was significantly positively correlated with statures at early childhood minimum, mid-childhood maximum, onset of adolescent and adolescent growth phases. Also positive significant correlations were found between VECM and VMC, VTO and PHV but in case of PHV and VMC, negative significant correlation was found. On the basis of JPA-2 model the mean adult stature were 171.27cm for Japanese boys and 158.51 for Japanese girls. On the basis of BTT model this study demonstrates that, on average, 46. 1 %, 39.5%, and 14.4% of the total adult stature were completed during early, middle and adolescent phase of growth, respectively, for the Japanese male population. For the female population, these percentages were 42.6%, 44.6%, and 12.8%, respectively. The distributions of predicted stature that do not have the mid growth spurt, on average, shows that the Japanese girls become taller than boys from age 1 to 5 and 10 to 12, and then again become shorter than boys. The distributions of predicted stature that have the mid growth spurt, on average, shows that the Japanese girls become taller than boys from age 8 and 11 to 12, and then again become shorter than boys. Japanese boys who do not have the mid growth spurt are, on average, 13.26 cm taller than their opposite sex. Moreover, Japanese boys who have the mid growth spurt are, on average, 13. 77 cm taller than their opposite sex. Several equations, after removing the problem of outliers and influential data points, are proposed to predict the adult stature of the Japanese based on growth parameters and statures at different ages.
Prediction of Final Stature from a New 3D Two-Stage Growth Model
(University of Rajshahi, 2015) Shahin, Md. Abu; Ali, Md. Ayub
The purpose of the present study was to establish higher dimensional growth model and then to predict the final stature from a new 3D two-stage growth model. To check the validity of the models, a secondary longitudinal data on age, weight and stature of Japanese boys and girls were used. The proposed 3D growth model showed more precise than that of the existing 2D growth models. After extracting the final stature and stature at different ages from the well fitted proposed model and eliminating the problem of multicollinearity using ‘Forward Stepwise Ridge Regression’ and ‘Least Absolute Shrinkage and Selection Operator (LASSO)’ techniques, this study propose four different equations for predicting final stature with higher precession, validity and stability compared to others. These equations are perfectly applicable in Japanese population. But, the form of the proposed model and its procedures can be applied to others populations.
Probability Pattern and Effect of Extinction of Disease on Expectation of Life in Bangladesh
(University of Rajshahi, 2014) Sarkar, Aziza Sultana Rosy; Islam, Md. Nurul
Mortality is one of the three components of population change. There are several causes of mortality which are different from country to country, age to age, sex to sex and present to past. A large number of people die every year by various causes of mortality in the world. Some causes of mortality mostly which are communicable are almost eradicated by following preemptive measures whereas some other causes of mortality i.e. non-communicable diseases exhibit challenging burden. In this study an investigation has been made to get a clear conception regarding mortality, morbidity and relevant issues. So, the purpose of this study is to examine the trends and probability patterns of deaths by age due to a cause of deaths in presence of all causes and also to identify the main causes of deaths those influence the mortality rate. An attempt has also been made the eliminating effect of specific diseases on expectation of life. Again, one of the components of population analysis is the study of differential of mortality classified by socioeconomic status and demographic characteristics. Thus this study attempts to identify important factors influencing non-communicable diseases related mortality. Finally, we find out the expected non-communicable disease related deaths in Bangladesh and setting the targets to control non-communicable diseases as a future plan in health sectors. Mortality trends and patterns in Bangladesh are primarily presented in the form of frequency distributions, prevalence rates, and mortality rates. This study uses Abridged Life table, Multiple Decrement Life table, Single Decrement Life table, Exponential Growth model, Polynomial Regression model, Logistic Regression model and ARIMA model for analyzing data to quantify the objectives of the study. This study uses the vital registration and maternal and child health data gathered from Matlab, Bangladesh in 2000, 2004 and 2008 collected by the Health and Demographic Surveillance System of ICDDR,B (International Centre for Diarrhea Disease Research, Bangladesh). Also, this study based on primary data which have been collected from 30th ward in Rajshahi City Corporation, Bangladesh. The result of this study shows that a huge number of people died because of non-communicable diseases. This number rapidly increases year by year at a large scale. Among non-communicable diseases, circulatory system related diseases (stroke, ischemic heart disease and hypertensive disease) is significant in Bangladesh. The second major cause of death is neoplasm for the national population. The analysis also warns that the burden of non-communicable diseases will significantly increase as the proportion of people aged over 40 rise. The government of Bangladesh should take necessary action to handle all the non-communicable diseases for achieving desired life expectancies in order to become a healthy nation. Some efforts have been made by governmental and non-governmental organization to set a sustainable system including physician and non-physician workers, health workers. In addition adequate supply and access to the essential medications is keenly ensured especially for the poor. Counseling services about the guidelines, treatments of non-communicable diseases for the male and female need to be arranged. Health services according to age and sex should be fixed up as an immediate goal to control the mounting trends of non-communicable diseases.
Statistical Modeling for Genome Wide Association Studies
(University of Rajshahi, 2020) Alam, Md. Jahangir; Mollah, Md. Nurul Haque; Hossain, Md. Ripter; Islam, S. M. Shahinul
Genomics is the study of the whole genome of any living organism along with its environment and it incorporates different elements from genetics (a branch of biology that generally deals with the heredity). Genomics uses “DNA sequencing methods” to generate sequences of genomes using recombinant DNA, and it utilizes Bioinformatics to assemble the sequences of whole genomes and analyze the structure and function of genomes. It differs from 'classical genetics' in that it considers an organism’s full complement of hereditary material, rather than one gene or one gene product at a time. Moreover, genomics focuses on interactions between loci and allele within the genome and other interactions such as epistasis, pleiotropy and heterosis (Figure 1.1). The availability of complete DNA sequences for entire organisms is made easy by the Genomics. Genomics was made possible by both the pioneering work of Fred Sanger and the more recent next-generation sequencing technology. Fred Sanger's group established techniques of sequencing, genome mapping, data storage, and bioinformatics analyses in the 1970s and 1980s. This work paved the way for the human genome project in the 1990s (Bentley et al., 2008) an enormous feat of global collaboration that culminated in the publication of the complete human genome sequence in 2003. Nowadays, next-generation sequence technologies have led to remarkable improvements in the speed, capacity and affordability of genome sequencing. Moreover, advances in bioinformatics have enabled hundreds of life- science databases and projects that provide support for scientific research. Information stored and organized in these databases can easily be searched, compared and analyzed………….