Inference on finite population categorical response: nonparametric regression-based predictive approach

Suppose that a finite population consists of N distinct units. Associated with the ith unit is a polychotomous response vector, d _i , and a vector of auxiliary variable x _i . The values x _i ’s are known for the entire population but d _i ’s are known only for the units selected in the sample. The problem is to estimate the finite population proportion vector P. One of the fundamental questions in finite population sampling is how to make use of the complete auxiliary information effectively at the estimation stage. In this article a predictive estimator is proposed which incorporates the auxiliary information at the estimation stage by invoking a superpopulation model. However, the use of such estimators is often criticized since the working superpopulation model may not be correct. To protect the predictive estimator from the possible model failure, a nonparametric regression model is considered in the superpopulation. The asymptotic properties of the proposed estimator are derived and also a bootstrap-based hybrid re-sampling method for estimating the variance of the proposed estimator is developed. Results of a simulation study are reported on the performances of the predictive estimator and its re-sampling-based variance estimator from the model-based viewpoint. Finally, a data survey related to the opinions of 686 individuals on the cause of addiction is used for an empirical study to investigate the performance of the nonparametric predictive estimator from the design-based viewpoint.     

Kolmogorov–Smirnov test for life test data with hybrid censoring

This work considers goodness-of-fit for the life test data with hybrid censoring. An alternative representation of the Kolmogorov–Smirnov (KS) statistics is provided under Type-I censoring. The alternative representation leads us to approximate the limiting distributions of the KS statistic as a functional of the Brownian bridge for Type-II, Type-I hybrid, and Type-II hybrid censored data. The approximated distributions are used to obtain the critical values of the tests in this context. We found that the proposed KS test procedure for Type-II censoring has more power than the available one(s) in literature.     

An application of nonparametric regression to missing data in large market surveys

Non-response (or missing data) is often encountered in large-scale surveys. To enable the behavioural analysis of these data sets, statistical treatments are commonly applied to complete or remove these data. However, the correctness of such procedures critically depends on the nature of the underlying missingness generation process. Clearly, the efficacy of applying either case deletion or imputation procedures rests on the unknown missingness generation mechanism. The contribution of this paper is twofold. The study is the first to propose a simple sequential method to attempt to identify the form of missingness. Second, the effectiveness of the tests is assessed by generating (experimentally) nine missing data sets by imposed MCAR, MAR and NMAR processes, with data removed.     

The molecular basis of age-related kidney disease

Renal disease affects 11% of people in the United States over the age of 65, not including those with diabetes or hypertension. Although glomerular disease is the most common underlying etiology of age-related renal dysfunction, the cause of glomerular disease and whether it is the only contributor to renal failure are not known. Our studies in female mice show that renal disease in the postmenopausal period is associated with progressive glomerular enlargement and scarring, as well as abnormal renal function. To study the underlying causes of aging-related glomerular disease, we isolated and characterized glomerular smooth muscle (mesangial) cells from female mice of various ages. We found that the cells from older mice exhibit a variety of phenotypic changes, including increased concentrations of p27, a protein that serves to inhibit progression from the G1 to the S phase of the cell cycle. Because the bone marrow (BM) contains mesangial cell progenitors that can transfer the donor glomerular phenotype (normal or diseased) to recipients, we exchanged BM between postmenopausal and premenopausal mice and found that aging-related glomerular enlargement and scarring are transferred to young recipient glomeruli. In addition, BM from normal, young donors led to the regression of aging-related glomerular disease in postmenopausal recipients; namely, both glomerular enlargement and scarring were reduced. Thus, aging-related glomerular disease is an entity distinct from all other causes of renal disease, is characterized by phenotypic changes in mesangial cell progenitors, and is reversible when the phenotype of the progenitors is returned to normal.     

A Decision Support System for Production/ Distribution Planning in Continuous Manufacturing

This paper presents a decision support system (DSS) for managing production/distribution planning in a continuous manufacturing environment. The vendor has multiple plants and distribution centers (DCs). The trading partners have widely varying independent demand patterns. The DSS is designed for use in a multiproduct environment with overlapping raw materials and processing requirements. The production and distribution lead times at plants may span multiple planning periods. The impact of any manual override of a suggested solution can also be evaluated. The DSS is based on a linear programming model with a rolling horizon and was originally designed for a large process industry. Results of a pilot implementation using actual data are also presented, which show potential for significant savings for the company.     

Looking beyond ‘buildings of chrome and glass’: Hong Kong’s ‘uncanny postcoloniality’ in photographs of Tin Shui Wai

Hong Kong has a unique postcolonial identity. After being colonised by Britain for over a century and a half, it was ceremoniously handed over to China in 1997, without necessitating any bloody wars or even skirmishes. Hong Kong has continued to enjoy a privileged status within China due to the doctrines enshrined in the ‘one country two systems’ policy. She has benefited from becoming part of a nation with the fastest growing economy in the world, and the people of Hong Kong have for the most part acquiesced to the reduction in levels of political freedom. However, recent events like the Umbrella Movement spearheaded mainly by student protesters has brought to the fore the cracks in Hong Kong’s postcolonial identity and the city finds itself once again precariously poised in a moment of transition.

Theorising a connection between Hong Kong’s postcolonial predicament and the city state’s physical landscape, I analyse Hong Kong photographer Derrick Chang’s photos of Tin Shui Wai, a remote new town located on Hong Kong’s northwestern edge. Tin Shui Wai is a failed new town – it was developed to house workers who would serve the industries that were projected to develop there in the 1990s. However, these labour-intensive industries never materialised due to the meteoric rise of Guangdong’s manufacturing industry. Instead Tin Shui Wai has now come to be known as the ‘city of sadness’, notorious for its gruesome murders, high rate of domestic abuse and tragic suicides. Through an analysis of Chang’s photographs of Tin Shui Wai depicting isolation, stagnation and urban detritus, this article argues that the uncanny, spectral spaces of encounter raise questions and provide an alternative and more disquieting narrative of Hong Kong’s postcolonial identity.     

Race,Religion, and the Social Integration of New Immigrant Minorities in Canada1

The social integration of Canada’s new religious minorities is determined more by their racial minority status than by their religious affiliation or degree of religiosity, according to results from Statistics Canada’s 2002 Ethnic Diversity Survey. Interview questions tap life satisfaction, affective ties to Canada, and participation in the wider community. Muslims, Sikhs, Buddhists, and Hindus are slower to integrate socially, mainly because they are mostly racial minorities. Degree of religiosity affects social integration in the same ways as ethnic community attachments in general, positively for some dimensions, negatively for others, and similarly for different religious groups. Patterns are similar in Quebec and the rest of Canada; results carry implications for the debate over “reasonable accommodation” of religious minorities in Quebec, and parallel debates in other provinces and countries.     

What’s in a Topic? Exploring the Interaction Between Test-taker Age and Item Content in High-Stakes Testing

The research reported in this article investigates differential item functioning (DIF) in a listening comprehension test. The study explores the relationship between test-taker age and the items’ language domains across multiple test forms. The data comprise test-taker responses (N = 2861) to a total of 133 unique items, 46 items of which were shared across two or more forms. Twenty-one items demonstrated DIF. However, there was no pattern by language domain. Eleven items showing DIF appeared in more than one test form but DIF for these items occurred only once.