我国丝绸出口贸易的经济分析

我国丝绸出口贸易的 "显示"比较优势指数呈逐年下降的趋势,但其数值一直保持在17以上,说明我国的丝绸出口与其他出口商品相比仍具有很大的竞争优势;我国丝绸出口的相对价格弹性系数为-0.3825,属于低弹性的商品.降低丝绸出口价格,不但无益于丝绸出口量的增加,反而会引起出口创汇额的明显下降,引起丝绸"出口贫困"现象的产生.稳定我国丝绸出口价格,是我国蚕丝业和丝绸贸易稳定发展的正确选择.     

Healthcare 4.0: trends,challenges and research directions

Abstract

This paper aims at examining the trends, challenges and theoretical gaps in the implementation of Healthcare 4.0 (H4.0) based on a scoping review of the literature. For that, we searched journal articles in four widely known databases and screened the retrieved articles to obtain a publications’ portfolio. Our findings indicate that, despite the recency of the subject, research in H4.0 has been conducted in an interdisciplinary way with a diversified set of applications and functionalities. In terms of its implementation, H4.0 has been more commonly found in hospitals’ information flows, especially the ones related to healthcare treatments. The identified implementation trends, however, neglect a more holistic approach for H4.0, which originated three main research directions for this topic. Although identified as a trending topic in the area of healthcare operations management, literature on H4.0 may be viewed as randomly conceived, lacking academic alignment and practical orientation based on a grounded theory, which we aim at providing with the present study.     

Psychophysical conditions and hormonal secretion in nurses on a rapidly rotating shift schedule and exposed to bright light during night work

The psychophysical conditions of 15 young female nurses, working in a rapidly-rotating shift system (2-2-2-2), modified according to some psychophysiological criteria, and exposed to short period (4 × 20 min) of bright light (2350 Lux) during their night duty, were studied in order to evaluate their adaptation to night work and to test a possible positive effect on it of bright light. Subjective evaluations of work load and psychophysical conditions, performance measures, hormonal excretion (cortisol, 6-sulphatoxymelatonin and catecholamines), oral temperature and activity-sleep logs were taken during the shiftwork cycle, comprising one morning, one afternoon and two consecutive nights under normal and bright light. The results showed that this rapidly-rotating shift system had little effect upon the normal circadian rhythms of the body. Moreover, the lengthening of the night shift to 10 h can be considered to be acceptable, provided that work load is reduced and there are sufficient rest pauses available. On the other hand, the reduction to 7 h of the length of the day shifts and delayed start of the morning shift to 07:00 h appeared to be convenient both in relation to the work load and sleep duration. Some positive effects of bright light upon psychophysical conditions and performance efficiency were noted, while hormonal excretion and body temperature did not show any effect of bright light; in particular, melatonin excretion was not suppressed appreciably by the bright light used.     

A general algorithm to fit constrained DEDICOM models

The DEDICOM model is a model to analyze square tables describing asymmetric relationships among n entities. Its importance in the asymmetric multidimensional scaling literature is due to the fact that several authors showed a large class of models to be simply a constrained version of DEDICOM. A typical example is the Generalized GIPSCAL proposed by Kiers & Takane. In this paper we present a new algorithm capable to fit, in the least squares sense, any DEDICOM constrained model.     

Psychophysical conditions of air traffic controllers evaluated by the standard shiftwork index

Abstract

In the ambit of a large epidemiological survey on the Italian population of air traffic controllers, an evaluation of their health conditions was carried out using the Standard Shiftwork Index (SSI). The study took into consideration 572 male air traffic controllers, aged between 23 and 59 years, of whom 301 were engaged in three large Regional Centres, 189 in thirteen Airport Towers and 82. formerly active controllers, were working in administrative offices. The former controllers showed worse health levels, in particular minor psychological disorders and chronic fatigue. Sixteen of them had been transferred to administrative jobs because of health impairment, owing to severe diseases of the nervous, gastrointestinal and cardiovascular systems. Such disorders, and musculoskeletal ones, were mostly reported by the active controllers. The controllers engaged in Regional Centres showed more sleep disturbances than those engaged in towers. Beside age, some personal characteristics appeared to influence health and well-being. Neuroticism was correlated with chronic fatigue, digestive and cardiovascular complaints, minor psychological disorders, cognitive and somatic anxiety. On the other hand, morningness was correlated negatively with sleep disturbances on morning shift, and positively with sleep duration both on morning shift and rest days.     

Modelling two way contingency tables with recursive logits and odds ratios

In this work a new type of logits and odds ratios, which includes as special cases the continuation and the reverse-continuation logits and odds ratios, are defined. We prove that these logits and odds ratios define a parameterization of the joint probabilities of a two way contingency table. The problem of testing equality and inequality constraints on these logits and odds ratios is examined with particular regard to two new hypotheses of monotone dependence. Work partially supported by a MIUR2004 grant. Preliminary findings have been presented at SIS (Società Italiana di Statistica) Annual Meeting, Torino, 2006.