Atmospheric peroxides over the North Pacific during IOC 2002 shipboard experiment

Atmospheric hydrogen peroxide and methyl hydroperoxide were determined onboard the Melville over the North Pacific from Osaka to Honolulu during May-June 2002. The concentrations of H(2)O(2) and CH(3)OOH increased from 0.64+/-0.57 ppbv and 0.27+/-0.59 ppbv in subpolar region (30-50 degrees N) to 1.96+/-0.95 ppbv and 1.56+/-1.3 ppbv in subtropical region (24-30 degrees N). The increase in concentrations towards the Equator was more pronounced for CH(3)OOH than H(2)O(2). In contrast, the levels of O(3) and CO were decreased at lower latitudes as air mass was more aged, denoted by the ratios of C(2)H(2)/CO and C(3)H(8)/C(2)H(6). CH(3)OOH concentrations showed a clear diurnal variation with a maximum around noon and minimum before sunrise. Frequently, the concentrations of peroxides remained over 1 ppbv in the dark and even gradually increased after sunset. In addition, the ratios of C(2)H(4)/C(2)H(6) and C(3)H(6)/C(3)H(8) were increased in aged subtropical air, which implies that these alkenes were emitted from the ocean surface. As a result, the reaction of these biogenic alkenes with O(3) was suggested to be a potential source for peroxides in aged marine air at lower latitudes.     

Trace metal concentration in Great Tit (Parus major) and Greenfinch (Carduelis sinica) at the Western Mountains of Beijing, China

We examined the concentrations of 11 trace metals in tissues from 10 body parts of Great Tits and Greenfinches collected at Badachu Park in the Western Mountains of Beijing, China to assess the metal accumulation level, distribution among body parts, and species and gender related variations. The highest concentrations of Hg, Ni, Zn, and Mn were found in the feather; Pb and Co in the bone; Cd, Cr, and Se in the kidney, and Cu in the liver and heart. Metal concentrations had substantial interspecific variation with Great Tits showing higher levels of Hg, Cr, Ni, and Mn than Greenfinches in tissues of most body parts. Gender related variations were body part and species specific. Meta-analyses using data from this study and other studies suggested that metal concentrations of Great Tits at our study site were relatively low and below the toxic levels.     

Assessment of the relative toxicity of Cu2+ by measuring structural changes of supercoiled DNA

A method for the measurement of the relative toxicity of Cu2+ in aquatic environments is proposed. It is based on the quantitative measurement on the shape change of the supercoiled DNA after it is contacted with different levels of Cu2+ for various time intervals. In the absence of any redox reagents, all supercoiled DNA degraded into other forms of DNA after 24h incubation in the presence of 5.13 x 10(-3), 5.08 x 10(-4) and 5.35 x 10(-5)mol/L Cu2+. At a lower Cu2+ concentration (10(-6)mol/L), 44% of supercoiled DNA retained its original supercoiled form after 24 h, and 29% after 48 h. The concentration of RC50, i.e. concentration of pollutants at which 50% of the supercoiled DNA was relaxed compared to control samples, can be obtained from the does-response curves at different exposure time, which may provide a rapid and convenient approach to assess the relative toxicity of environmental pollutants.     

淮安市农产品中重金属及有机氯、有机磷农药残留量调查

淮安市环境监测中心站于1999年－2000年对淮安市农产品中重金属以及有机氯、有机磷农药残留量进行了调查。结果表明，粮食和蔬菜作物中，六六六的4种同分异构体只有γ－六六六能检出，检出率分别为24．0％和51．7％，都未超标；DDT的4种同分异要体均未检出；有机磷农药的检出率分别为5％和25％，其中蔬菜中敌敌畏含量出现个别超标现象，倍硫磷、乐果和杀螟松在粮食和蔬菜作物中的含量都不超标。重金属中金属“五毒”在粮食和蔬菜作物中，只有Cr和Pb能检出，Cd、Hg和As都未检出，Cu、Zn和Mn能检出，但不超标。提出，应严格按照农牧渔业部和卫生部颁发的《农药安全使用规定》用药，多使用高效低残留量的“绿色农药”；农业、环保和卫生部门必须加强合作，对蔬菜生产销售的全过程进行监督监测，以确保生产无公害蔬菜。     

外源锌对镉胁迫下玉米幼苗生长及根系构型分级的影响

为探究不同浓度锌（Zn）对镉（Cd）胁迫条件下玉米幼苗生长及根系构型分级的影响,通过水培试验,以玉米品种郑单958为试验材料,研究Cd胁迫条件下（50 μmol·L^-1）,外源施加不同浓度Zn（0、10、25、50、100、200和400 μmol·L^-1）对玉米幼苗生长、根系构型及其分级特征、Cd含量及根系Cd吸收能力、光合系统的影响,并通过主成分分析和隶属函数法进行综合评价.结果表明,50 μmol·L^-1 Cd胁迫对玉米幼苗具有明显的毒害作用,使叶绿素含量和光合参数显著降低,主根长、株高、生物量、根分枝数和根尖数,包括Ⅰ~Ⅲ级径级区间的根长、根表面积及Ⅰ~Ⅱ级径级区间的根体积显著下降,阻碍了玉米幼苗的正常生长发育.施用100 μmol·L^-1和200 μmol·L^-1 Zn与不施Zn相比,降低了玉米幼苗对Cd的吸收,显著降低了Cd含量和Cd吸收效率,缓解了对玉米幼苗的毒害作用,使地上地下部鲜重、地上部干重、地上地下部耐受指数和根分枝数均显著升高;显著增强了玉米幼苗的光合作用,促使幼苗光合速率和总叶绿素含量显著升高;Ⅰ级径级区间的RL、Ⅰ~Ⅱ级径级区间的SA和RV在100 μmol·L^-1 Zn时达到最大,Ⅲ级径级区间的RL、SA和RV在200 μmol·L^-1 Zn时达到最大,均显著高于不施Zn处理;玉米幼苗生长耐受性综合评价表明,100 μmol·L^-1和200 μmol·L^-1 Zn缓解Cd毒害作用效果较好.综合分析可知,施加适宜浓度的Zn可以降低玉米幼苗植株内Cd含量、根系Cd吸收能力及Cd吸收效率,提高玉米幼苗生物量的积累,减轻Cd毒害对根系构型的影响,减少对光合系统的影响,提高玉米幼苗对Cd的耐受性.     

Search and rescue in collapsed structures: engineering and social science aspects

This paper discusses the social science and engineering dimensions of search and rescue (SAR) in collapsed buildings. First, existing information is presented on factors that influence the behaviour of trapped victims, particularly human, physical, socioeconomic and circumstantial factors. Trapped victims are most often discussed in the context of structural collapse and injuries sustained. Most studies in this area focus on earthquakes as the type of disaster that produces the most extensive structural damage. Second, information is set out on the engineering aspects of urban search and rescue (USAR) in the United States, including the role of structural engineers in USAR operations, training and certification of structural specialists, and safety and general procedures. The use of computational simulation to link the engineering and social science aspects of USAR is discussed. This could supplement training of local SAR groups and USAR teams, allowing them to understand better the collapse process and how voids form in a rubble pile. A preliminary simulation tool developed for this purpose is described.     

Persistence of airline accidents

This paper expands on air travel accident research by examining the relationship between air travel accidents and airline traffic or volume in the period from 1927–2006. The theoretical model is based on a representative airline company that aims to maximise its profits, and it utilises a fractional integration approach in order to determine whether there is a persistent pattern over time with respect to air accidents and air traffic. Furthermore, the paper analyses how airline accidents are related to traffic using a fractional cointegration approach. It finds that airline accidents are persistent and that a (non‐stationary) fractional cointegration relationship exists between total airline accidents and airline passengers, airline miles and airline revenues, with shocks that affect the long‐run equilibrium disappearing in the very long term. Moreover, this relation is negative, which might be due to the fact that air travel is becoming safer and there is greater competition in the airline industry. Policy implications are derived for countering accident events, based on competition and regulation.     

Jailed resources: conservation of resources theory as applied to burnout among prison guards

This study evaluates a salutogenic perspective of the burnout process. Building upon Hobfoll's ( 1989 ) Conservation of Resources theory, it proposes a simultaneous test of three hypothesized resources‐based models. These competing models test the structure of burnout in relation to depleted resources (e.g., lack of skill utilization, of participation, of co‐worker support, and of professional worth) and negative correlates (e.g., absenteeism and depression). SEM results provide equally good support for two resource‐based models, although each of them proceeds from two different approaches (Leiter vs. Golembiewski). Of all burnout components, personal accomplishment is found to be least related to resources depletion, while emotional exhaustion is the most related to absenteeism and depression. Results are analyzed in light of existing literature and of the specific nature of the sample, a large population of French correctional officers (n = 707). Implications for burnout theory and human resource management are discussed. Copyright © 2006 John Wiley & Sons, Ltd.     

Character in organizational research: past directions and future prospects

Character (ethos) refers to those interpenetrable habitual qualities within individuals, and applicable to organizations that both constrain and lead them to desire and pursue personal and societal good. In our Incubator article, we undertake two objectives. First, we provide our conceptualization of character; briefly specifying what character is and is not. Second, we introduce several promising directions for organizationally based research on character. Copyright © 2008 John Wiley & Sons, Ltd.