Selection of a stroke risk model based on transcranial Doppler ultrasound velocity

Increased transcranial Doppler ultrasound (TCD) velocity is an indicator of cerebral infarction in children with sickle cell disease (SCD). In this article, the parallel genetic algorithm (PGA) is used to select a stroke risk model with TCD velocity as the response variable. Development of such a stroke risk model leads to the identification of children with SCD who are at a higher risk of stroke and their treatment in the early stages. Using blood velocity data from SCD patients, it is shown that the PGA is an easy-to-use computationally variable selection tool. The results of the PGA are also compared with those obtained from the stochastic search variable selection method, the Dantzig selector and conventional techniques such as stepwise selection and best subset selection.     

Religion, religiosity and educational attainment of immigrants to the USA

This paper quantifies the association between religions, religiosity and educational attainment of new lawful immigrants to the US. This paper considers a broad set of religions that includes most of the major religions of the world. Using data from the New Immigrant Survey (2003), we show that affiliation with religion is not necessarily associated with an increase in educational attainment. Muslim and “Other religion” immigrants have less education compared to the immigrants who are not affiliated with any religion. However, affiliation with the Jewish religion is associated with higher educational attainment for males. With regard to religiosity, our results show that high religiosity is associated with lower educational attainment, especially for females. We also outline alternative frameworks that provide insight about the mechanisms that link religion and religiosity with educational attainment.     

Pelvic organ prolapse: review of the aetiology, presentation, diagnosis and management

Pelvic organ prolapse is a common condition affecting a large number of women. Incidence increases after the menopause. Age, parity and obesity are the most consistently reported risk factors. Many women can be asymptomatic of prolapse but common symptoms include a sensation of a bulge or fullness in the vagina or urinary, bowel or sexual dysfunction. Management depends upon symptoms and the type and grade of the prolapse as well as any associated medical co-morbidities. Management options include expectant, conservative or surgical approaches. Up to 10% of women having a surgical procedure for prolapse will require a second procedure. It is, therefore, important to consider lifestyle modifications such as weight loss and conservative measures including pelvic floor muscle training, topical estrogens and pessaries as initial management options.     

Implementation of continuous flow manufacturing (CFM) system

In a world of global competition and demanding customers, putting production requirements ahead of customer's needs inevitably leads to manufacturing inefficiencies, higher inventories, and poor quality goods and services. In continuous flow manufacturing (CFM) system, the manufacturer makes how much and what is needed, and also when it is needed. A leading multinational company in oral care products produces toothbrushes through contract manufacturers (CMs). The contract manufacturer makes different stock-keeping units (SKUs) under two options: (i) the contract manufacturing option, in which CM supplies the finished products; (ii) the labour contract, in which CM is responsible only for conversion. Competitive pressure in the market pressures the company to change the operating system from the push system to CFM for CMs also. Moving from the push system with its high level of inventories to continuous flow manufacturing system enables the achievement of improved customer responsiveness, greater efficiencies, lower inventories and lower operating costs. This paper describes the way in which one such contract manufacturer was moved towards the CFM system and the benefits achieved through it.     

Note on umvsu-estimation under randomized response model

Considering a class ofs randomized response trials for eliciting sensitive information from a sample survey and a class of ordered sampling designs, a uniformly minimum variance unbiased estimator of population variance (of the sensitive character) has been obtained. This note indicates that a theorem (theorem 3.9) of Cassel, Sarndal and Wretman (1977) and the results in the present note can be extended to estimation of any symmetric function of population values in the field of direct response surveys and randomized response surveys respectively.     

On the optimalizes of the mbgdd's under mixed effects model

In the present paper, under the assumption of a mixed effects model with random block effects, the type 1 optimality of the most balanced group divisible designs of type 1 has been established within the general class of all proper and connected block designs with k<v.     

Bounded risk estimation of linear combinations of the location and scale parameters in exponential distributions under two-stage sampling

Two-stage sampling is proposed for estimating linear combinations of the location and scale parameters of exponential distributions with bounded quadratic risk functions. Exact formulae for the expected values and risks of the estimators are derived, and the performance of estimators is studied. Illustrations with real data are included.     

Robust designs for multinomial models

Abstract

Model misspecification in generalized linear models (GLMs) occurs usually when the linear predictor and/or the link function assumed are incorrect. This article discusses the effect of such misspecification on design selection for multinomial GLMs and proposes the use of quantile dispersion graphs to select robust designs. Due to misspecification in the model, parameter estimates are usually biased and the designs are compared on the basis of their mean squared error of prediction. Several numerical examples including a real data set are presented to illustrate the proposed methodology.