An approximation to percentiles of a variable of the bivariate normal distribution when the other variable is truncated,with applications

A Cornish-Fisher expansion is used to approximate the per-centiles of a variable of the bivariate normal distribution when the other variable is truncated. The expression is in terms of the bivariate cumulants of a singly truncated bivariate normal distribution. The percentiles are useful in the problem of personnel selection where we use a screening variable to screen applicants for employment and a correlated performance variable to screen employees for rehiring. This paper provides a bivariate cumulants table for determining the cutoff score of the performance variable. The following two problems are also con¬sidered: (1) determine the proportion of applicants who would have been successful had no screening been applied, and (2) determine the proportion of individuals being rejected byscreening who would have been successful had they been hired, The variable that is used to measure job performance and the variable that measures the outcome of an aptitude test are assumed to be jointly normally distributed with correlation ρ     

Scheduling in an assembly-type production chain with batch transfer

This paper addresses a three-machine assembly-type flowshop scheduling problem, which frequently arises from manufacturing process management as well as from supply chain management. Machines one and two are arranged in parallel for producing component parts individually, and machine three is an assembly line arranged as the second stage of a flowshop for processing the component parts in batches. Whenever a batch is formed on the second-stage machine, a constant setup time is required. The objective is to minimize the makespan. In this study we establish the strong NP-hardness of the problem for the case where all the jobs have the same processing time on the second-stage machine. We then explore a useful property, based upon which a special case can be optimally solved in polynomial time. We also study several heuristic algorithms to generate quality approximate solutions for the general problem. Computational experiments are conducted to evaluate the effectiveness of the algorithms.     

Heuristic for scheduling in a two-machine bicriteria dynamic flowshop with setup and processing times separated

This paper addresses the two-machine bicriteria dynamic flowshop problem where setup time of a job is separated from its processing time and is sequenced independently. The performance considered is the simultaneous minimization of total flowtime and makespan, which is more effective in reducing the total scheduling cost compared to the single objective. A frozen-event procedure is first proposed to transform a dynamic scheduling problem into a static one. To solve the transformed static scheduling problem, an integer programming model with N ² + 5N variables and 7N constraints is formulated. Because the problem is known to be NP-complete, a heuristic algorithm with the complexity of O (N ³) is provided. A decision index is developed as the basis for the heuristic. Experimental results show that the proposed heuristic algorithm is effective and efficient. The average solution quality of the heuristic algorithm is above 99%. A 15-job case requires only 0.0235 s, on average, to obtain a near or even optimal solution.     

A rapid systematic review on the association between childhood physical and sexual abuse and illicit drug use among males

This paper aims to review studies in relation to the association between childhood physical (CPA) and sexual abuse (CSA) and illicit drug use among the male clinical and general community populations using a systematic approach. Primary studies were identified using online databases which were searched comprehensively using a set of pre‐determined search criteria and terms. Other sources included expert contact and the reference list of a relevant review. Associations between exposure (CPA/CSA) and outcome (illicit drug use) were considered with regards to an array of factors. A total of 5012 references were initially identified out of which 18 studies met the necessary criteria for reviewing. The review demonstrates tentative support for factors such as earlier drug initiation, intravenous drug use and greater frequency of use among some of the samples. It also demonstrates the difficulties involved in drawing conclusions due to the complex and multifaceted nature of drug use and the variability in the quality of the research available in this area. Limitations of the current review are highlighted and recommendations offered for future research with consideration given to practical implications in clinical and forensic settings. Copyright © 2010 John Wiley & Sons, Ltd.     

抗旱剂一号在川西北地区小麦上的应用研究

通过对抗旱剂一号在川西北地区小麦上拌种和在不同时间以不同剂量喷雾两方面研究,结果表明:拌种能增加小麦三叶期、五叶期的次生根数、根长及其地上部的鲜、干重,能减少无效分蘖数,提高上林率。抗旱剂一号拌种、分蘖期和孕穗期喷雾均能增加小麦的单穗绿叶数。拌种最佳剂量为50kg麦种200g,喷施的最佳时期和最佳剂量分为分蘖期,每公顷300g。拌种和喷施对产量均无显著影响、其优势主要在前期。     

The microeconomics of distribution: A simulation of the farm economy

A simulation model that incorporates both production and consumption behavior of farm households in Taiwan is presented. The model is used to analyze the effects of policy instruments (price supports, minimum wages, taxes, subsidies, demographic policies, and land and capital redistribution) on the aggregate values of the endogenous variables of the system—the supplies of output and labor, the demands of factors and consumption, income and expenditure—and their distribution among households. The model differs from other simulation models in that it is based on microsimulation, in which the joint distribution of individual household characteristics such as farm-specific prices, initial endowments of land and capital, and numbers of workers and dependents, is explicitly taken into account. As a result, the model is capable of capturing the distributional as well as aggregate impacts of policy changes.     

Trends in Child Poverty in Hong Kong Immigrant Families

In Hong Kong, child poverty is a serious social problem which may lead to intergenerational poverty, but nevertheless only a few studies have examined this issue, particularly for immigrant families. Using Census data (5 %) from 1981, 1991, 2001, and 2011, we assessed child poverty rates in the past three decades and identified key variables contributing to changes in the risk of child poverty for both immigrant and local families. Our results indicate that child poverty rates in Hong Kong-born families have fluctuated between 14.3 and 15.8 % over the past three decades, while for immigrant families they have increased steadily and substantially from 18.1 % in 1981 to 36.5 % in 2001 and then to 37.5 % in 2011. We show that the increase in immigrant child poverty is associated with changes in the Hong Kong economy that have made it more difficult for such families to adapt to the host society, especially in the 1990s and that this negative effect offset the positive influence of compositional changes among this group of immigrant families in terms of parental education levels and family size. The gap between immigrant and local families in terms of child poverty risk is mainly due to the fact that during the 1990s the negative effect of contextual changes in Hong Kong was cancelled out by the beneficial impact of compositional changes for local families, but not for immigrant families where the latter effect was minimal.     

And Neither Are We Saved: Asian Americans' Elusive Quest for Racial Justice

Derrick Bell, Civil Rights activist, legal scholar, and a founder of critical race theory, dedicated much of his life and scholarship to the pursuit of racial justice. Twenty‐six years ago, in his work And We Are Not Saved, he recognized that racial progress has been stalled and racial equality would not be a reality in his lifetime. Bell passed away in October 2011, and we are reminded that there is still much work to do. He presented a conundrum that race scholars have said all there is to say about racial problems in the United States; yet, he encouraged scholars to keep moving the work forward. At the time And We Are Not Saved was written, much of the racial scholarship was centered on the Black–White paradigm. In the 26 years since Bell wrote it, there has been a growth of Asian American research. This essay surveys some critical racial analysis of Asian Americans. There have been major contributions to the literature extending racial scholarship beyond the Black–White paradigm. Additionally, intersectional scholarship extends the discussion into other systems of oppression, highlighting how racism can be veiled in different systems. Critical race scholarship is imperative to keep Bell's dream of racial equality alive.     

Familial Effect on Child Poverty in Hong Kong Immigrant Families

This study investigated how family context affect poverty disparities between young children of immigrants from the Mainland China and children of local families whose parents were born in Hong Kong using 2006 bicensus data. 12,609 and 12,753 children of immigrant and local families were included in our data analyses. We find higher child poverty rates in immigrant families than in local families. Moreover, we found that family structure (single-parent vs. 2-parent), assimilation (first vs. second generation children of immigrant families), and parental human capital characteristics are significantly associated with the child poverty risk. Surprisingly, the impact of immigrant status on child poverty rates is stronger in 2-parent households than in single-parent households while child poverty declines associated with increasing assimilation defined by generational status of children are greater in 2-parent immigrant families than the corresponding declines in single-parent immigrant families. The implications of our results in intergenerational poverty are discussed.     

Analytic approaches for assessing long-term treatment effects. Examples of empirical applications and findings

Analytic approaches, including the structural equation model (autoregressive panel model), hierarchical linear model, latent growth curve model, survival/event history analysis, latent transition model, and time-series analysis (interrupted time series, multivariate time-series analysis) are discussed for their applicability to data of different structures and their utility in evaluating temporal effects of treatment. Methods are illustrated by presenting applications of the various approaches in previous studies examining temporal patterns of treatment effects. Recent advancements in these longitudinal modeling approaches and the accompanying computer software development offer tremendous flexibility in examining long-term treatment effects through longitudinal data with varying numbers and intervals of assessment and types of measures. A multimethod assessment will contribute to a more complete understanding of the complex phenomena of the long-term courses of substance use and its treatment.