Comment: Fisher Lecture: Dimension Reduction in Regression

Comment: Fisher Lecture: Dimension Reduction in Regression [arXiv:0708.3774]Comment: Published at http://dx.doi.org/10.1214/088342307000000050 in the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Consumption Smoothing and Vulnerability in Russia

Applying bootstrapped quantile regression to the Russian Longitudinal Monitoring Survey (RLMS) data, we examine the channels through which individuals experience and seek to cope with changes in consumption. We find that married individuals living in small households, with educated heads in urban areas are better equipped to smooth consumption. Investigating the impact of idiosyncratic shocks, we find that the labour market is an important transmission mechanism allowing households to smooth their consumption but also exposing them to risk, mainly through job loss. Outside of pension payments the formal social safety net does not facilitate consumption smoothing, thus heightening the importance of informal coping institutions. It transpires that both support from relatives/friends and home production act as important insurance mechanisms for the most vulnerable.http://deepblue.lib.umich.edu/bitstream/2027.42/64415/1/wp885.pd

Bounds on the natural frequencies of laminated rectangular plates with extension-twisting (and shearing-bending) coupling

Anti-symmetric angle-ply laminates are widely believed to uniquely possess Extension-Twisting (together with Shearing-Bending) coupling behaviour. The results in this article serve to dispel this misconception by presenting solutions for both standard laminates, containing combinations of angle plies (+45 and -45) and cross plies (90 and/or 0), and angle-ply laminates, containing only +45 and -45 ply orientations; chosen to reflect current industrial design practice, and also because they serve to produce hygro-thermally curvature-stable properties in some standard laminate configurations, i.e., with immunity to the thermal distortions that generally arise in this class of mechanically coupled laminate as a result of the high temperature curing process. Details of the algorithm used to develop the definitive list of laminate stacking sequences, with up to 21 plies, are given first. Closed form natural frequency solutions for each of these sub-groups are then presented, identifying significant differences in the frequency spectrum bounds across a range of aspect ratios, with respect to the ubiquitous anti-symmetric angle-ply designs

A NEW PERSPECTIVE ON CHINA TRADE GROWTH: APPLICATION OF A NEW INDEX OF BILATERAL TRADE INTENSITY

This paper analyzes China’s trade relationships using a new trade intensity index, which incorporates gravity model estimation, to compare observed trade levels with levels would be expected to prevail given the economic, geographic, and cultural characteristics of the trading partners. The index is calculated to study China’s bilateral trade intensity, and uses Japan as a comparative case. Standard trade intensity index measures suggest China trades at a very intensive level with countries in East and Southeast Asia (ESA) and at a low level with countries in Europe (EU) and US-Canada (USC). The gravity model based index indicates that China’s level of trade with countries in the ESA region is consistent with levels that would be expected given the countries’ characteristics, while China’s level of trade with EU and USC are greater than one would expect given their characteristics. The new index also reveals insights regarding the evolution of China’s trade partners during the years 1988-2005. The paper’s results suggest the gravity model adjusted trade intensity index can provide a useful analytical tool for identifying strategic or other deviations in trade levels.Gravity model, Trade Intensity Index, Bilateral Trade, China

Employees’ perceptions of human resource management practices and employee outcomes

Purpose – The purpose of this paper is to examine the relationship between employees’ perceptions of HRM practices and two outcomes, namely, employee commitment and turnover intention, in small and medium-sized enterprises (SMEs) in mainland China.Design/methodology/approach – This paper adopts a quantitative approach based on a sample of 227 employees working in 24 SMEs in eastern and western China.Findings – Employees’ perceptions of HRM practices such as training and development, reward management, and performance management, are significant predictors of employee commitment. A negative direct relationship is found between employees’ perceptions about the use of HRM practices and turnover intentions.Research limitations/implications – Although data were collected from two representative provinces of eastern and western China, the size of the sample may limit the generalisability of the findings to the wider region.Practical implications – The relationship between employees’ perceptions of HRM practices and employee outcomes in Chinese SMEs provides an effective way for SME owners and HR practitioners to generate desirable employee attitudes and behaviours, which, ultimately contribute to improving organisational performance.Originality/value – This is an original paper which makes a contribution by helping to address the dearth of studies which have explored aspects of the effectiveness of HRM in SMEs in China. In contrast to the majority of China-focused studies on this topic, it highlights HRM outcomes at the individual level rather than the organisational level. Further, the study involves SMEs in western China which is an under-explored region

tRNA splicing

Introns interrupt the continuity of many eukaryal genes, and therefore their removal by splicing is a crucial step in gene expression. Interestingly, even within Eukarya there are at least four splicing mechanisms. mRNA splicing in the nucleus takes place in two phosphotransfer reactions on a complex and dynamic machine, the spliceosome. This reaction is related in mechanism to the two self-splicing mechanisms for Group 1 and Group 2 introns. In fact the Group 2 introns are spliced by an identical mechanism to mRNA splicing, although there is no general requirement for either proteins or co-factors. Thus it seems likely that the Group 2 and nuclear mRNA splicing reactions have diverged from a common ancestor. tRNA genes are also interrupted by introns, but here the splicing mechanism is quite different because it is catalyzed by three enzymes, all proteins and with an intrinsic requirement for ATP hydrolysis. tRNA splicing occurs in all three major lines of descent, the Bacteria, the Archaea, and the Eukarya. In bacteria the introns are self-splicing (1-3). Until recently it was thought that the mechanisms of tRNA splicing in Eukarya and Archaea were unrelated as well. In the past year, however, it has been found that the first enzyme in the tRNA splicing pathway, the tRNA endonuclease, has been conserved in evolution since the divergence of the Eukarya and the Archaea. Surprising insights have been obtained by comparison of the structures and mechanisms of tRNA endonuclease from these two divergent lines