The development and validation of a psychological contract of safety scale

Introduction

This paper builds on previous research by the author and describes the development and validation of a new measure of the psychological contract of safety. The psychological contract of safety is defined as the beliefs of individuals about reciprocal safety obligations inferred from implicit and explicit promises.

Method

A psychological contract is established when an individual believes that perceived employer and employee safety obligations are contingent on each other. A pilot test of the measure is first undertaken with participants from three different occupations: nurses, construction workers, and meat processing workers (N = 99). Item analysis is used to refine the measure and provide initial validation of the scale. A larger validation study is then conducted with a participant sample of health care workers (N = 424) to further refine the measure and to determine the psychometric properties of the scale.

Results

Item and correlational analyses produced the final employer and employee obligations scales, consisting of 21 and 17 items, respectively. Factor analyses identified two underlying dimensions in each scale comparable to that previously established in the organizational literature. These transactional and relational-type obligations provided construct validity of the scale. Internal consistency ratings using Cronbach's alpha found the components of the psychological contract of safety measure to be reliable.

Impact on Industry

The refined and validated psychological contract of safety measure will allow investigation of the positive and negative outcomes associated with fulfilment and breach of the psychological contract of safety in future research.     

张家口地区枯水期地下水水化学特征及其成因机制分析

为更好支撑首都水源涵养功能区和生态环境支撑区建设,开展张家口地区枯水期地下水水化学特征及其形成机制研究,对地下水资源合理开发利用具有重要参考意义.采集41组地下水样品,运用描述性统计分析、Piper三线图、相关性分析、Gibbs图及离子比值等方法,分析了研究区地下水水化学类型、组成特征和控制因素.结果表明,研究区地下水整体呈弱碱性,总硬度变化范围为105.00~1 433.00 mg·L^-1,ρ（TDS）变化范围在137.00~2 286.00 mg·L^-1,坝上地区地下水中总硬度和TDS质量浓度均高于坝下地区.研究区地下水中HCO₃^-和Na⁺为主要优势阴、阳离子.地下水中主要组分超标率最高的为总硬度,超标率为36.59%,坝上地区地下水中各组分的超标率和最大超标倍数均大于坝下地区.研究区地下水水化学类型以HCO₃-Ca·Mg·Na型为主,坝上地区和坝下地区水化学类型差异较小,SO₄^2-、Cl^-、HCO₃^-、Na⁺和Mg²⁺对TDS的贡献最大.地下水水化学特征受盐岩、钠长石和白云岩等岩石矿物风化溶滤作用、阳离子交换作用和人类活动的共同影响,蒸发结晶和大气降水对研究区地下水主要离子来源贡献较小.坝上地区地下水受人类活动影响要大于坝下地区,其中NO₃^-主要来源于农业活动.     

Role of information in collective action in dynamic disaster environments

This study explores the major issues facing collective response operations after destructive earthquakes. The small-n case study design employs qualitative and quantitative methods to investigate the decision-making process in a context of seismic risk to exemplify how public managers can utilise information and communication systems to ensure collaborative actions in managing an extreme event. Fifty-eight semi-structured interviews with 39 key decision-makers and researchers and content analyses of daily reports from Cumhuriyet comprise the main data sources. The study compares and contrasts the Turkish disaster management system following the Marmara and Duzce earthquakes of 1999. It addresses whether the use of information and communication technologies significantly affected its performance. The study's findings reveal that difficulties in accessing and exchanging timely and accurate disaster-relevant information inhibited coordination during the Marmara response while increased communication functions improved coordination and search-and-rescue activities during the Duzce response.     

Mason Valley Groundwater Model: Linking Surface Water and Groundwater in the Walker River Basin,Nevada1

Carroll, Rosemary W.H., Greg Pohll, David McGraw, Chris Garner, Anna Knust, Doug Boyle, Tim Minor, Scott Bassett, and Karl Pohlmann, 2010. Mason Valley Groundwater Model: Linking Surface Water and Groundwater in the Walker River Basin, Nevada. Journal of the American Water Resources Association (JAWRA) 46(3):554-573. DOI: 10.1111/j.1752-1688.2010.00434.x Abstract: An integrated surface water and groundwater model of Mason Valley, Nevada is constructed to replicate the movement of water throughout the different components of the demand side of water resources in the Walker River system. The Mason Valley groundwater surface water model (MVGSM) couples the river/drain network with agricultural demand areas and the groundwater system using MODFLOW, MODFLOW’s streamflow routing package, as well as a surface water linking algorithm developed for the project. The MVGSM is capable of simulating complex feedback mechanisms between the groundwater and surface water system that is not dependent on linearity among the related variables. The spatial scale captures important hydrologic components while the monthly stress periods allow for seasonal evaluation. A simulation spanning an 11-year record shows the methodology is robust under diverse climatic conditions. The basin-wide modeling approach predicts a river system generally gaining during the summer irrigation period but losing during winter months and extended periods of drought. River losses to the groundwater system approach 25% of the river’s annual budget. Reducing diversions to hydrologic response units will increase river flows exiting the model domain, but also has the potential to increase losses from the river to groundwater storage.     

阳离子交换膜对Cu~（2＋）离子交换的动力学及热力学研究

对阳离子交换膜离子交换Cu2＋的动力学及热力学现象进行了研究,结果表明：温度25℃,溶液pH=6时,干膜对Cu2＋饱和交换容量为0.506 mmol/g;随Cu2＋初始浓度的升高,离子交换速率常数随之增加;随温度升高,离子交换速率常数随之增加;随转速升高,离子交换速率常数随之增加;离子交换过程与一级反应速率方程拟合结果良好;△G0〈0,表明离子交换反应能自发进行;△H0m〉0,表明的交换反应为吸热反应;△S0〉0,表明交换反应是熵变增加的反应。     

铜、锌氰配合物在离子交换纤维上的扩散、吸附机理

运用Boyd液膜扩散公式和范山鹰等提出的扩散模型,考察了碱性溶液中铜、锌氰配合物在离子交换纤维上的扩散行为;通过分析吸附前后纤维上官能团的位置变化以及解吸前后纤维上元素含量的变化,研究铜、锌氰配合物在纤维上的吸附机理。实验结果表明,离子交换纤维对铜、锌配合物的吸附在反应初期,以液膜扩散为主控制步骤,反应后期,以空隙扩散为主控制步骤。并运用离子交换纤维在水溶液中具有类似胶体型物质的双电层结构解释了不同控制阶段吸附速率不同的原因,虽然各阶段吸附速率有所不同,但纤维对铜、锌氰配合物的吸附均为离子交换机制。     

Removal of heavy metals from aqueous solution by sawdust adsorption

The adsorption of lead, cadmium and nicel from aqueous solution by sawdust of walnut was investigated. The effect of contact time, initial metal ion concentration and temperature on metal ions removal has been studied. The equilibrium time was found to be of the order of 60 min. Kinetics fit pseudo first-order, second-order and intraparticle diffusion models, hence adsorption rate constants were calculated. The adsorption data of metal ions at temperatures of 25, 45 and 60~C have been described by the Freundlich and Langmuir isotherm models. The thermodynamic parameters such as energy, entropy and enthalpy changes for the adsorption of heavy metal ions have also been computed and discussed. Ion exchange is probably one of the major adsorption mechanisms for binding divalent metal ions to the walnut sawdust. The selectivity order of the adsorbent is Pb（I1）~Cd（II）〉Ni（I1）. From these results, it can be concluded that the sawdust of walnut could be a good adsorbent for the metal ions from aqueous solutions.     

长江口湿地沉积物-水界面无机氮交换总通量量算系统研究

基于MapObjects组件式GIS技术和数学建模方法,以Visual Basic为开发平台,建立了长江口湿地沉积物-水界面无机氮交换通量空间插值模型、总通量量算模型和量算系统,该系统的主要功能包括对无机氮界面交换通量信息查询检索,空间插值分析,以及对长江口湿地不同岸段、不同季节无机氮交换总通量综合和动态量算.利用该系统和长江口湿地2000年10月-2004年7月无机氮界面交换通量季节性实测数据,对长江口湿地沉积物-水界面无机氮交换总通量进行了量算.结果表明:长江口湿地沉积物在春季向水体释放无机氮,在夏季、秋季和冬季则表现为净化水体中的无机氮,全年总体表现为净化水体中的无机氮.量算系统的实际应用表明,该系统在定量分析长江口湿地生态功能过程中发挥了重要作用.      

城市大气污染物对PEMFC性能的影响

论述了城市空气污染物(即阴极气体杂质)对质子交换膜燃料电池(PEMFC)性能的影响。提出了燃料电池汽车(FCV)进入商业化应用时即将面临的一个急待研究的课题。文中综述了CO、CO2、硫化物、碳氢化合物(HC)、氮氧化物(NOx)、NH3、卤素离子(X-)、酸沉降物以及大气颗粒物等对PEMFC性能的影响,同时对解决阴极气体杂质影响的途径进行了分析。     

贵州红枫湖地区冷暖两季土壤/大气界面间汞交换通量的对比

采用动力学通量箱(Dynamic Flux Chamber,DFC)与高时间分辨率自动大气测汞仪联用技术,于2002年7月和2003年3月对红枫湖地区土壤/大气界面上汞交换通量进行了测定.夏冬2季土壤-大气汞的交换通量分别为(27.4±40.1)ng·(m²·h)^-1(n=255)和(5.6±19.4)ng·(m²·h)^-1(n=192).夏季汞交换通量和光照、气温及土壤温度的相关系数分别为0.74、0.83和0.80,而冬季分别为0.88、0.56和0.59.对比研究表明:暖季土壤向大气的释汞通量远高于冷季;2个季节光照、温度等气象因素对土壤/大气界面间汞交换均有重要的影响.