利用修复试验了解在酸化压力下的鱼类种群的恢复动态

我们的生态修复试验涉及放养两种本地的游钓鱼品种湖鳟(Salvelinus namaycush)和小口黑鲈(Micropterus dolomieu),结合最近的鱼类群落调查,研究了加拿大安大略省萨德伯里和基拉尼附近酸化湖泊中的鱼类种群的恢复动态.在两个品种之间,种群恢复率有差异.在品种丰富的湖泊中引进的湖鳟恢复得慢,其生长显得较慢、存活率较低和群体补充延迟.相反,小口黑鲈能在品种丰富的湖泊里迅速繁殖.随着水质的恢复和放养鱼开始产卵,小口黑鲈的自然补充群体的生物量在5年之内增加到了参考湖泊的水平,而湖鳟的自然补充群体的生物量在水质恢复和成鱼产卵后5～15年内仍然停留在参考湖泊的水平以下.我们记录到游钓者把小口黑鲈引进了受酸化损害的湖鳟湖泊,包括一些酸化前没有黑鲈的湖泊.能改变食物网结构和降低冷水性鱼类湖鳟生长的温水性鱼类黑鲈分布区的扩张表明,气候变暖再加上品种引进有可能大大改变酸化湖泊的生物恢复端点.     

High beam headlamp use rates: Effects of rurality,proximity of other traffic,and roadway curvature

Objective: The few observational studies of the prevalence of high beam use indicate the rate of high beam use is about 25% when vehicles are isolated from other vehicles on unlit roads. Recent studies were limited to 2-lane rural roads and used measurement methods that likely overestimated use. The current study examined factors associated with the rate of high beam use of isolated vehicles on a variety of roadways in the Ann Arbor, Michigan area.

Methods: Twenty observation sites were categorized as urban, rural, or on a rural/urban boundary and selected to estimate the effects of street lighting, road curvature, and direction of travel relative to the city on high beam use. Sites were selected in pairs so that a majority of traffic passing one site also passed through the other. Measurement of high beams relied on video data recorded for 2 nights at each site, and the video data also were used to derive a precise measure of the proximity of other traffic. Nearly 3,200 isolated vehicles (10 s or longer from other vehicles) were observed, representing 1,500-plus vehicle pairs.

Results: Across the sample, 18% of the vehicles used high beams. Seventy-three percent of the 1,500-plus vehicle pairs used low beams at each paired site, whereas 9% used high beams at both sites. Vehicles at rural sites and sites at the boundaries of Ann Arbor were more likely to use high beams than vehicles at urban sites, but use in rural areas compared with rural/urban boundary areas did not vary significantly. Rates at all sites were much lower than expected, ranging from 0.9 to 52.9%. High beam use generally increased with greater time between subject vehicles and leading vehicles and vehicles in the opposing lane. There were mixed findings associated with street lighting, road curvature, and direction of travel relative to the city.

Conclusion: Maximizing visibility available to drivers from headlights includes addressing the substantial underuse of high beam headlamps. Advanced technologies such as high beam assist, which switches automatically between high and low beam headlamps depending on the presence of other traffic, can help to address this problem.     

Evaluating the blue-light hazard from solid state lighting

Purpose. New light sources including light-emitting diodes (LEDs) have elicited questions about retinal damage, including the blue-light hazard. Some organizations have recommended avoiding using LEDs with correlated color temperatures exceeding 3000?K, since they tend to produce greater short-wavelength energy. This article provides quantitative comparisons among light sources and use cases as they affect the blue-light hazard. Methods. The spectral radiant power characteristics of incandescent, fluorescent, LED and daylight sources were evaluated in terms of blue-light hazard using standard procedures for phakic, aphakic and pseudophakic eyes. Results. Under most use cases, LEDs do not exhibit greater risk for the blue-light hazard than other sources (e.g., incandescent). Because they generally produce little to no ultraviolet energy, LEDs often present less risk to aphakic eyes. Conclusions. LEDs present no special concerns for the blue-light hazard over some other common sources in typical use cases because photophobic responses limit exposure to bright sources. Where photophobic responses might not occur (e.g., eye surgery patients or premature infants) or where individuals suppress these responses (e.g., stage actors), caution is necessary. Evidence remains inconsistent regarding the risk of human retinal damage from long-term exposures to light insufficient to reach acute blue-light hazard thresholds.     

A multilevel study of group‐focused and individual‐focused transformational leadership,social exchange relationships,and performance in teams

Using matched reports from 73 team leaders and 359 of their members across 23 companies in Korea, we examined a multilevel model where group‐ and individual‐focused transformational leadership and their influence processes operate at the team and dyadic levels independently and interactively to be associated with team and member performance. Results indicated that group‐focused transformational leadership was positively associated with team performance through team member exchange (TMX), whereas individual‐focused transformational leadership positively related to team members' in‐role and extra‐role performance through leader–member exchange (LMX). TMX not only positively mediated the relationships between group‐focused transformational leadership and member performance after controlling for LMX but also positively moderated LMX–performance relationships. Moreover, the indirect effect of individual‐focused transformational leadership through LMX on member performance was contingent upon the level of TMX. Theoretical and applied implications are discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

The problem with [in] management theory

Theory is essential to everything that we do as people studying and practicing industrial/organizational psychology and organizational behavior. But, I think that our field has lost its way recently and become enamored by shiny objects and interesting puzzles. Advancing management theory seems to have become an end state in and of itself. We seemed to be far more concerned with the entertainment value of theories than we are with their scientific rigor or real‐world value. Top journals in our field are mandating that all articles must make a theoretical contribution, and theoretical contributions are being gauged primarily in terms of how innovative, counter‐intuitive, surprising, and interesting they may be. I advocate for a more balanced approach, and in particular, for greater use of abductive inference. I argue that if you start with a real‐world challenge and draw from existing theory, and then develop new theory to understand and change things, you are also making a theoretical contribution. Whether or not we are guided by theory is not really at issue—at issue is how well developed are our theories, how accurate are they, and do they help us to improve organizational life for everyone involved?     

Risk factors affecting the severity of traffic accidents at Shanghai river-crossing tunnel

Objective: With increasing traffic volume and urban development, increasing numbers of underground tunnels have been constructed to relieve conflict between strained land and heavy traffic. However, as more long tunnels are constructed, tunnel traffic safety is becoming increasingly serious. Thus, it is necessary to acquire their implications and impacts. This study examined 4,539 traffic accidents that have occurred in 14 Shanghai river-crossing tunnels for the period 2011–2012 and analyze the correlation between potential factors and accident injury severity.

Methods: An ordered logit model was developed to examine the correlation between potential factors and accident injury severity.

Results: Results show that increased injury severity is associated with male drivers, drivers aged 65 years or older, accident time from midnight to dawn, weekends, wet road surface, goods vehicles, 3 or more vehicles, 4 or more lanes, middle speed limits (50–79 km/h), zone 3, extra-long tunnels (over 3,000 m), and maximum longitudinal gradient.

Conclusions: This article aims to provide useful information for engineers to develop interventions and countermeasures to improve tunnel safety in China.     

What kinds of injuries do OSHA inspections prevent?

Objective

OSHA's enforcement program is one of the major public efforts to protect American workers. We examine both the scope of injury prevention that inspections can contribute and the types of standards that contribute the most.

Methods

We linked Pennsylvania Department of Labor and Industry files for lost-time injuries and employment to calculate injury rates for 1998-2005 for all single-establishment manufacturing firms. We linked these to OSHA inspection records.

Results

Inspections with penalties did affect injury types unrelated to standards as well as those related. We also found again that citations for violations of the standard requiring personal protective equipment had the largest impact on preventing injuries.

Impact on Industry

Programs requiring protective equipment use deserve added attention from consultants and inspectors. In addition, some inspections spur managers to undertake safety measures that go beyond compliance with standards.