Estimation of noncentrality parameters

We propose some estimators of noncentrality parameters which improve upon usual unbiased estimators under quadratic loss. The distributions we consider are the noncentral chi-square and the noncentral F. However, we give more general results for the family of elliptically contoured distributions and propose a robust dominating estimator.     

Estimates of fertility in Bangladesh

The attempt is made to estimate fertility levels in Bangladesh on the basis of data collected during the 1974 Census. In the 1st section attention is directed to providing an overall picture of the demographic situation in the country. Comparisons between the 1961 and 1974 data demonstrates that the 1974 Census data provide consistent results. Factors such as the degree of urbanization, literacy and economic participation rates--considered as indicators of development--all seem to show little progress during the intercensal period. The use of child/women ratios (CWRs) provides plausible evidence of the likelihood of a fertility decline. A decline in CWR values is small for "all areas" but a marked decline can be noted for "urban areas." The recorded mean number of children is less in 1974 than in 1961 for women under age 35 whereas for the older groups the 1974 Census shows higher mean numbers. The Bangladesh Fertility Survey (BFS) data result for the total fertility rate of 6.58 is very close to that estimated for the 1974 Census--6.59. The reverse survival method also indicates that birthrates have been lower during the 1969-1974 period.     

On E-Bayesian estimations for the cumulative hazard rate and mean residual life under generalized inverted exponential distribution and type-II censoring

Estimation of reliability and hazard rate is necessary in many applications. To this aim, different methods of estimation have been employed. Each method suffers from its own problems such as complexity of calculations, high risk and so on. Toward this end, this study employed a new method, E-Bayesian, for estimating the parametric functions of the Generalized Inverted Exponential distribution, which is one of the most noticeable distributions in lifetime studies. Relations are derived under a squared error loss function, type-II censoring and a conjugate prior. E-Bayesian estimations are obtained based on different priors of the hyperparameters to investigate the influence of different prior distributions on these estimations. The asymptotic behaviors of E-Bayesian estimations and relations among them have been investigated. Finally, a comparison among the maximum likelihood, Bayes and E-Bayesian estimations in different sample sizes are made, using a real data and the Monte Carlo simulation. Simulations show that the new presented method is more efficient than previous methods and is also easy to operate. Also, some comparisons among the results of Generalized Inverted Exponential distribution, Exponential distribution and Generalized Exponential distribution are provided.KEYWORDS: E-Bayesian estimation, generalized Inverted exponential distribution, type-II censoring, reliability, hazard rate, Monte Carlo simulation     

A semiparametric approach for modelling multivariate nonlinear time series

In this article, a semiparametric time‐varying nonlinear vector autoregressive (NVAR) model is proposed to model nonlinear vector time series data. We consider a combination of parametric and nonparametric estimation approaches to estimate the NVAR function for both independent and dependent errors. We use the multivariate Taylor series expansion of the link function up to the second order which has a parametric framework as a representation of the nonlinear vector regression function. After the unknown parameters are estimated by the maximum likelihood estimation procedure, the obtained NVAR function is adjusted by a nonparametric diagonal matrix, where the proposed adjusted matrix is estimated by the nonparametric kernel estimator. The asymptotic consistency properties of the proposed estimators are established. Simulation studies are conducted to evaluate the performance of the proposed semiparametric method. A real data example on short‐run interest rates and long‐run interest rates of United States Treasury securities is analyzed to demonstrate the application of the proposed approach. The Canadian Journal of Statistics 47: 668–687; 2019 © 2019 Statistical Society of Canada     

Modified profile likelihood estimation for the Weibull regression models in survival analysis

In this study, adjustment of profile likelihood function of parameter of interest in presence of many nuisance parameters is investigated for survival regression models. Our objective is to extend the Barndorff–Nielsen’s technique to Weibull regression models for estimation of shape parameter in presence of many nuisance and regression parameters. We conducted Monte-Carlo simulation studies and a real data analysis, all of which demonstrate and suggest that the modified profile likelihood estimators outperform the profile likelihood estimators in terms of three comparison criterion: mean squared errors, bias and standard errors.     

Analysis of microtubule dynamics using growth curve models

Microtubules are part of the structural network within a cell's cytoplasm, providing structural support as well as taking part in many of the cellular processes. A large body of data provide evidence that dynamics of microtubules in a cell is reponsible for the performance of many critical cellular functions such as cell division. In this article, we study the effect of four different isoforms of a protein tau on microtubule dynamics using growth curve models. The results show that a linear growth curve model is sufficient to explain the data. Moreover, we find that a mutated version of a 3-repeat tau protein has a similar effect as a 4-repeat tau protein on microtubule dynamics. The latter findings conform with the biological understanding of the effect of the protein tau on microtubule dynamics.     

The Feminist “Quarantine” on Hijab: A Study of Its Two Mutually Exclusive Sets of Meanings

The discourse on feminism is sharply polarized between those who regard hijab as essentially debilitating and those who see it as an enabling tool for dignity, self-worth and freedom. This article will discuss both the negative and positive associations of hijab and point out ways it is used by Muslim women for liberatory ends. It will go against the grain of a common argument that hijab equates seclusion and constraints on women’s participation in public life hence it is inherently oppressive. I will argue that hijab can potentially be used for diametrically opposite purposes. While acknowledging the fact that the Islamic dress code for women can be misused by patriarchal power systems as well as by women themselves, I will put forth arguments against dismissive and uncritical criticism of hijab.     

Challenges of implementing restorative justice for intimate partner violence: An Islamic perspective

ABSTRACT

Intimate partner violence (IPV) is currently recognized as a critical public health concern and a human rights issue. Not surprisingly, Muslims – a religiously and socio-culturally diverse faith-based populace – are not an exception. To address this complex area of criminal justice and social policy, some scholars advocate implementing restorative justice (RJ) approaches. While RJ approaches have been traditionally used in Islamic cultures for conflict resolutions, to date, few studies have investigated how RJ operates in dealing with IPV in Muslim countries and communities. This article explores how RJ approaches towards IPV operate in some Muslim countries/communities, and offers insights into developing culturally and religiously appropriate ways of implementing RJ in IPV situations among Muslims. Given the prevalence of IPV among Muslims, the question is particularly important and timely. Taking exclusively limited examples of RJ approaches that have been used to mediate IPV cases in Muslim countries and communities, this paper found one significant challenge in the RJ approaches among Muslims: community acceptance of IPV. To reduce IPV in Muslim society, it is necessary to develop treatment models and techniques that meet cultural and religious needs. This paper found that since RJ is not alien to Islamic teachings, RJ approaches can be implemented effectively in dealing with IPV among Muslims by ensuring justice and equity of the abused woman. The findings of this paper will assist policymakers, practitioners, and service providers in providing religiously and culturally appropriate care when addressing IPV issues among Muslims.     

Migration pattern in Bangladesh: a covariate-dependent Markov model

Internal migration is one of the major components of rapid and unplanned growth of towns and cities especially in the developing countries. This paper describes the transition pattern of internal out migration in Bangladesh and some sociodemographic factors influencing such migration in the country using a covariate-dependent Markov model. Four types of migration behavior namely, rural to rural, rural to urban, urban to rural and urban to urban are under consideration of this paper. Defining two discrete states, urban and rural, each of such transition can be characterized by a stochastic process; hence we use a two-state Markov chain for this purpose. We find that age, sex, division and reason of migration are significantly associated with internal migration in Bangladesh. The major findings include that any type of migration, rural to rural, rural to urban, urban to rural and urban to urban, mostly take place at the ages of 15–30 as well as at the ages of 0–15; females have higher odds than males to make a migration; Dhaka, Rajshahi and Chittagong divisions have remarkably higher migration rate as compared to Barisal and Sylhet division; and the professional reason is the main reason for rural to urban migration.