高校青年教师职业道德建设的社会机制探析

文章从当前高校青年教师职业道德的特殊性和现状出发,对其职业道德建设的主要社会机制及存在的问题进行了剖析,并且坚持教师职业道德的理想要求与高校青年教师个体全面发展相统一的原则,对新形势下适应高校青年教师职业道德建设的社会机制及其体系的建构进行了探讨.     

我国经营者实现职业化的最低成本途径分析

探讨了我国经营者职业化的目标，并从“经营者才能”商品化这个角度出发，分析了经营者实现职业化的最低成本途径，初步提出了我国经营者职业化机制的基本构架。     

A unified signal transition graph model for asynchronous control circuit synthesis

Characterization of the behavior of an asynchronous system depending on the delay of components and wires is a major task facing designers. Some of these delays are outside the designer's control, and in practice may have to be assumed unbounded. The existing literature offers a number of analysis and specification models, but lacks a unified framework to verify directly if the circuit specification admits a correct implementation under these hypotheses.Our aim is to fill exactly this gap, offering both low-level (analysis-oriented) and high-level (specification-oriented) models for asynchronous circuits and the environment where they operate, together with strong equivalence results between the properties at the two levels. One interesting side result is the precise characterization of classical static and dynamic hazards in terms of our model. Consequently the designer can check the specification and directly decide if the behavior of any implementation will depend, e.g., on the delays of the signals described by such specification.We also outline a design methodology based on our models, pointing out how they can be used to select appropriate high and low-level models depending on the desired characteristics of the system.     

核工业职业性照射个人剂统计与评价(1985—1990年)

本文介绍了核工业系统职业性照射个人剂量监测(1985—1990年)的概况和主要结果。统计结果表明,核工业各厂、院、所等单位放射性工作人员1985—1990年的外照射年集体剂量当量分别为29.88、26.95、19.16、14.26、9.08和9.22人·Sv;年人均剂量当量分别为4.98、4.66、3.65、2.79、2.40和2.27 mSv。对内照射个人剂量监测情况进行了简要介绍,给出了部分单位铀、钚、氚等核素的内照射剂量监测数据,各有关厂、院的年人均待积有效剂量当量均低于5.0 mSv。还概述了铀矿山职业性照射个人剂量监测结果。最后,对个人剂量监测数据作了初步的评价分析。     

ICRP第二分委员会及其有关工作组成员在“职业性和公众受照人员放射性核素摄入学术讨论会”上的报告内容简介

１９９７年９月１５至１８日，国际放射防护委员会（ＩＣＲＰ）第二分委员会在法国Ａｖｉｇｎｏｎ举行了“职业性和公众受照人员放射性核素摄入学术讨论会”。本文简要介绍了ＩＣＲＰ第二分委员会及其有关工作组成员共１５人在大会上报告的题目及主要内容。     

Comparison between a Weibull proportional hazards model and a linear model for predicting the genetic merit of US Jersey sires for daughter longevity

Predicted transmitting abilities (PTA) of US Jersey sires for daughter longevity were calculated using a Weibull proportional hazards sire model and compared with predictions from a conventional linear animal model. Culling data from 268,008 Jersey cows with first calving from 1981 to 2000 were used. The proportional hazards model included time-dependent effects of herd-year-season contemporary group and parity by stage of lactation interaction, as well as time-independent effects of sire and age at first calving. Sire variances and parameters of the Weibull distribution were estimated, providing heritability estimates of 4.7% on the log scale and 18.0% on the original scale. The PTA of each sire was expressed as the expected risk of culling relative to daughters of an average sire. Risk ratios (RR) ranged from 0.7 to 1.3, indicating that the risk of culling for daughters of the best sires was 30% lower than for daughters of average sires and nearly 50% lower than than for daughters of the poorest sires. Sire PTA from the proportional hazards model were compared with PTA from a linear model similar to that used for routine national genetic evaluation of length of productive life (PL) using cross-validation in independent samples of herds. Models were compared using logistic regression of daughters' stayability to second, third, fourth, or fifth lactation on their sires' PTA values, with alternative approaches for weighting the contribution of each sire. Models were also compared using logistic regression of daughters' stayability to 36, 48, 60, 72, and 84 mo of life. The proportional hazards model generally yielded more accurate predictions according to these criteria, but differences in predictive ability between methods were smaller when using a Kullback-Leibler distance than with other approaches. Results of this study suggest that survival analysis methodology may provide more accurate predictions of genetic merit for longevity than conventional linear models.     

Environmental factors associated with crash-related mortality and injury among taxi drivers in New South Wales, Australia

This exploratory study aims to investigate the associations between some environmental factors and the increased risk of motor vehicle crash-related injuries among taxi drivers. Information utilised in the study are obtained from police reports of all road traffic accidents that occurred on the roads between 1996 and 2000 in New South Wales (NSW), Australia. Of the 7923 taxi drivers who involved in crashes, nearly 10% (n = 750) were killed or injured. Results indicate sex, and two environmental factors are significantly associated with an increased risk of crash-related mortality and injury among taxi drivers. The adjusted relative risk of crash-related mortality and injury is increased by 60% for those who work the night shift (OR = 1.59, 95%CI = 1.35-1.88), and by 20% for those who do not carry any passenger on board (OR = 1.20, 95%CI = 1.02-1.41) should these drivers involve in a crash. The increased relative risk of crash-related mortality and injury is nearly 2.5 times for female taxi drivers (OR = 2.30, 95%CI = 1.45-3.65) when compared with their male counterparts.     

Matched-pair cohort methods in traffic crash research

Standard analysis of matched-pair cohort data requires information only from pairs in which at least one had the study outcome. This can be useful in traffic fatality studies of characteristics that can vary among vehicle occupants, such as seat belt use, as crash databases often lack information about vehicles in which all survived. However, matching crash victims who were in the same vehicle does not necessarily eliminate confounding by vehicle or crash related factors, because the matched occupants must be in different seat positions. This paper reviews three methods for estimating relative risks in matched-pair crash data. The first, Mantel-Haenszel stratified methods, may produce biased estimates if seat position is associated with the outcome. The second, the double-pair comparison method, was designed to deal with confounding by seat position. If the effects of seat position vary according to some vehicle or crash characteristic which is associated with the study exposure, adjustment for this characteristic may be needed to produce unbiased estimates. Third, conditional Poisson regression and Cox proportional hazards regression can produce unbiased estimates, but may require model interaction terms between seat position and vehicle or crash characteristics. This paper reviews some of the strengths and limitations of each of these methods, and illustrates their use in simulated and real crash data.     

An improved algorithm for the detection of plumes caused by natural or technological hazards using AVHRR imagery

Fires caused by natural or technological disasters emit large amounts of smoke which, once formed into plumes, may affect the human health and the environment. Satellite remote sensing data provide an effective tool to achieve detection and monitoring of these plumes over large areas on a routine basis. Discrimination of plumes on satellite images is a prerequisite to study and retrieve physical, chemical and optical properties of emitted smoke. An improved algorithm for the detection of plumes caused by natural or technological hazards using AVHRR imagery is presented in this study. The method is based on a multi-temporal and multi-spectral change detection algorithm. It is performed in two main steps: a) appropriate spectral and spatial filters are applied on the images acquired before and after a fire event in visible and near-infrared ranges in order to extract the core of the plume; b) a criterion on spectral information is defined as an homogeneity measure that enables, through a modified version of the region-growing method, the spatial expansion of the detected core to include the complete area covered by the plume. Through this approach, a pixel is identified as a plume pixel if it is “close” to the core plume pixels in both spatial and spectral spaces. The algorithm was developed and calibrated using AVHRR images acquired over Spain before and during a major forest fire event on July 16, 2005. It was applied using past events of natural and technological hazards in several locations to ensure its global applicability and robustness. The algorithm produced accurate results in all cases of plumes, either in natural or in technological fire events. Three application cases are presented in this study: A major fire in an industrial installation in London (December 11, 2005), a major fire in Baghdad during the recent war in Iraq (April 1, 2003) and a forest fire in California (September 29, 2005).     

Design of PH-based accelerated life testing plans under multiple-stress-type

Accelerated life testing (ALT) is used to obtain failure time data quickly under high stress levels in order to predict product life performance under design stress conditions. Most of the previous work on designing ALT plans is focused on the application of a single stress. However, as components or products become more reliable due to technological advances, it becomes more difficult to obtain significant amount of failure data within reasonable amount of time using single stress only. Multiple-stress-type ALTs have been employed as a means of overcoming such difficulties. In this paper, we design optimum multiple-stress-type ALT plans based on the proportional hazards model. The optimum combinations of stresses and their levels are determined such that the variance of the reliability estimate of the product over a specified period of time is minimized. The use of the model is illustrated using numerical example, and sensitivity analysis shows that the resultant optimum ALT plan is robust to the deviation in model parameters.