Conformal normal curvature and assessment of local influence

In 1986, R. D. Cook proposed differential geometry to assess local influence of minor perturbations of statistical models. We construct a conformally invariant curvature, the conformal normal curvature, for the same purpose. This curvature provides a measure of local influence ranging from 0 to 1, with objective bench-marks to judge largeness. We study various approaches to using the conformal normal curvature and the relationships between these approaches.     

Exploring Research Data Hosting at the HKUST Institutional Repository

The profusion of data created by modern research has brought about increasing discussion on the practice of data management and the development of such infrastructure. Many universities and libraries are exploring how to address this issue using institutional repositories, the Hong Kong University of Science and Technology (HKUST) Library being one of them. As part of the exploration, the author conducted a case study of datasets at major institutional repositories. This paper visits the issues relating to data archiving, reports common practices of data treatment at institutional repositories, and presents a list of recommendations for experimenting data archiving at the HKUST Institutional Repository.     

Comparison of disease prevalence in two populations under double-sampling scheme with two fallible classifiers

A disease prevalence can be estimated by classifying subjects according to whether they have the disease. When gold-standard tests are too expensive to be applied to all subjects, partially validated data can be obtained by double-sampling in which all individuals are classified by a fallible classifier, and some of individuals are validated by the gold-standard classifier. However, it could happen in practice that such infallible classifier does not available. In this article, we consider two models in which both classifiers are fallible and propose four asymptotic test procedures for comparing disease prevalence in two groups. Corresponding sample size formulae and validated ratio given the total sample sizes are also derived and evaluated. Simulation results show that (i) Score test performs well and the corresponding sample size formula is also accurate in terms of the empirical power and size in two models; (ii) the Wald test based on the variance estimator with parameters estimated under the null hypothesis outperforms the others even under small sample sizes in Model II, and the sample size estimated by this test is also accurate; (iii) the estimated validated ratios based on all tests are accurate. The malarial data are used to illustrate the proposed methodologies.     

Opportunistic data structures for range queries

In this paper, we study the problem of supporting range sum queries on a compressed sequence of values. For a sequence of n k-bit integers, k ≤ O(log n), our data structures require asymptotically the same amount of storage as the compressed sequence if compressed using the Lempel-Ziv algorithm. The basic structure supports range sum queries in O(log n) time. With an increase by a constant factor in the storage complexity, the query time can be improved to O(log log n + k). The work described in this paper is fully supported by a grant from the Research Grant Council of the Hong Kong Special Administrative Region, China (CityU 1071/02E). A preliminary version has appeared in 11th International Conference in Computing and Combinatorics (COCOON'05).     

Youth Justice in New Zealand: Restorative Justice in Practice?

The Children, Young Persons, and Their Families Act 1989 put in place new objects, principles, and procedures for youth justice in New Zealand. Both the philosophy underpinning this system and the use of family group conferences exemplify a restorative justice approach that has now been adopted in many other countries. This article describes these changes and presents some of the results of recently published research that examines the extent to which young offenders have been diverted from courts and custody, held accountable for their actions, and had their wellbeing enhanced. It suggests that the New Zealand youth justice system has achieved many but not all of its goals, and that there are still aspects where improvement is possible.     

Belief in a Loving Versus Punitive God and Behavior

We examined the extent to which beliefs in a loving God and punitive God correspond with self‐reported behavior in an online, longitudinal survey involving three waves of data collection, each separated by 6 months. Adolescents (N = 760) reported the extent to which they believed in a loving God and a punitive God (Times 1 and 3) and reported their engagement in benevolent (helping and forgiveness) and aggressive behavior (Times 2 and 3). Participants strongly endorsed a loving God but not a punitive God. In addition, belief in a loving God corresponded with reports of less aggressive and more benevolent behavior, whereas belief in a punitive God corresponded with more aggressive and less benevolent behavior.     

Why does the need for medication become a barrier to breastfeeding? A narrative review

Problem

The need for medication during lactation can contribute to the early cessation of breastfeeding.