The effect of an active steering system on city bus drivers’ muscle activity

City bus drivers spend hours driving under time pressure, in congested traffic and in a monotonous sitting position. This leads to unhealthy working conditions, especially in terms of physical and psychological stress. The aim of this study is to investigate whether an active steering system can alleviate the musculoskeletal stress involved in manoeuvring a bus. Twenty bus drivers drove a city bus equipped with the Volvo dynamic steering (VDS) support system in real traffic. Steering effort was evaluated with electromyography and with a questionnaire. Compared to baseline, VDS significantly reduced the required muscle activity by on average 15–25% while turning, and up to 68% in the part of the manoeuvre requiring maximum effort. The bus drivers believed that VDS will help reduce neck and shoulder problems, and they expressed a desire to have VDS installed in their own bus.     

基于SEM的铁路客运安全影响因素分析*

随着我国铁路的飞速发展,选择铁路出行的人越来越多,安全是出行最基本的保障。为了确保铁路客运安全,首先根据铁路客运安全评价体系,从工作人员、旅客、设备、管理、环境5个因素探讨对铁路客运安全的影响;其次建立铁路客运安全结构方程模型(SEM),提出假设关系;以部分铁路为例设计并发放铁路安全调查问卷,利用SPSS25.0分析调查问卷的效度,检测问卷的可靠性;最后运用Amos17.0验证分析模型的假设关系。将产生的拟合系数与标准指标相比较,核对拟合系数是否在标准指标的范围内,并适当地修正模型,直到各项拟合指标都达标后确定影响铁路客运安全的主要因素。研究结果表明:工作人员、设备、管理、环境4个因素对铁路客运安全有正态显著的影响,可以通过改善加强人员管理、提高设备安全、改善车站、列车环境等提高铁路客运安全。     

QFD在铁路客运站安全服务质量评价中的应用*

为提高铁路客运站的安全服务质量,加强铁路客运安全管理,根据铁路旅客运输对车站服务质量的要求标准,结合质量功能展开法(QFD)评价铁路客运站的安全服务质量。首先,通过专家评定确定安全服务指标间的关系矩阵,并据此构建测评质量屋;其次,根据最大关联度原则筛选同级安全指标,找出其中与安全功能质量联系最大的技术指标,并构成判断矩阵,计算指标的重要度;然后,根据判断矩阵和技术指标重要度得出旅客的总满意度,从而评价客运站的安全服务质量;最后,以某铁路客运站为例,验证QFD法的有效性和实用性。研究结果表明:QFD法能定量分析铁路客运站安全服务水平,从旅客的需求找出铁路客运站的安全服务存在的问题,从而帮助客运站改进安全服质量。     

Age dependency of high-affinity ouabain receptors and their magnetosensitivity

Age dependency of [³H]-ouabain binding, ⁴⁵Ca²⁺ eflux and its magnetosensitivity in rats’ brain cortex and heart muscle tissues were studied. Curves of dose-dependent [³H]-ouabain binding consisted of three components with different affinities (10⁻⁷–10⁻⁴ M (α₁); 10⁻⁹–10⁻⁷ M (α₂); and 10⁻¹¹–10⁻⁹ M (α₃)). These curves were also characterized by different dose-dependent kinetics. [³H]-ouabain binding with α₃ receptors in brain cortex and heart muscle tissues of young and adult animals had a dose-dependent character, while that in old ones had a dose-independent character. A 0.2 T static magnetic field (SMF) exposure had modulation effect on ouabain binding with α₁, α₂ and α₃ receptors in young rats, while in adult ones, only α₃ receptors were magnetosensitive. In old animals, SMF exposure had no significant effect on ouabain binding with α₃ receptors in brain cortex, while in heart muscle, it had inhibitory effect on it. Age-dependent effect of ouabain impact on ⁴⁵Ca²⁺ efflux showed that all concentrations of ouabain lead to inhibitory effect in young animals’ brain cortex and heart muscle (with the exception of 10⁻¹⁰ and 10⁻⁶ M), while in old ones, it had activation effect as compared with data received without ouabain. SMF exposure in young animals had activation effect on ⁴⁵Ca²⁺ efflux from brain cortex and heart muscle in data without ouabain, and in old rats, ⁴⁵Ca²⁺ efflux from brain cortex was magnetic insensitive. In old animals, SMF increased ⁴⁵Ca²⁺ efflux even after extra low concentration of ouabain. It is suggested that α₃ receptors having a crucial role in the regulation of Na⁺/Ca²⁺ exchange serve as age-dependent magnetosensors of excitable cells.     

Road Traffic and Nearby Grassland Bird Patterns in a Suburbanizing Landscape

An extensive road system with rapidly increasing traffic produces diverse ecological effects that cover a large land area. Our objective was to evaluate the effect of roads with different traffic volumes on surrounding avian distributions, and its importance relative to other variables. Grassland bird data (5 years) for 84 open patches in an outer suburban/rural landscape near Boston were analyzed relative to: distance from roads with 3000–8000 to >30,000 vehicles/day; open-habitat patch size; area of quality microhabitat within a patch; adjacent land use; and distance to other open patches. Grassland bird presence and regular breeding correlated significantly with both distance from road and habitat patch size. Distance to nearest other open patch, irrespective of size, was not significant. Similarly, except for one species, adjacent land use, in this case built area, was not significant. A light traffic volume of 3000–8000 vehicles/day (local collector street here) had no significant effect on grassland bird distribution. For moderate traffic of 8000–15,000 (through street), there was no effect on bird presence although regular breeding was reduced for 400 m from a road. For heavier traffic of 15,000–30,000 (two-lane highway), both bird presence and breeding were decreased for 700 m. For a heavy traffic volume of ≥30,000 vehicles/day (multilane highway), bird presence and breeding were reduced for 1200 m from a road. The results suggest that avian studies and long-term surveys near busy roads may be strongly affected by traffic volume or changes in volume. We conclude that road ecology, especially the effects extending outward >100 m from roads with traffic, is a sine qua non for effective land-use and transportation policy.     

Effects of smelter sulfur dioxide emissions: a spatiotemporal perspective using carbon isotopes in tree rings

We wanted to test the hypothesis that forest exposure to phytotoxic gases indirectly affects their carbon uptake. We estimated that the reduction of photosynthesis may have reached 20 to 30% at a site located 9 km (test site) from the Horne copper smelter in Rouyn-Noranda, which is a point source of SO2. Twenty-one spruce trees older than 100 yr were selected from seven sites at various distances from the smelter to evaluate conditions prior to and during the periods of smelter operation. The carbon isotope results obtained from spruce tree rings at our test site reveal an unprecedented and abrupt shift of +4/1000 after the onset of smelter operations. This large and permanent shift exceeds natural variations in regional pre-smelter series or in the series at a remote control site. All trees up to 116 km downwind from the smelter show delta13C positive shifts following the onset of operations. There is also a clear inverse relationship between the amplitude of the first-order trends and distance from the smelter. Those delta13C trends indicate that trees exposed to high levels of SO2 decrease their level of CO2 uptake through activation of stomatal closure. This is strongly supported by the significant departure of the Rouyn-Noranda trends from those measured for trees from non-industrialized areas of the Northern Hemisphere, or calculated using global atmospheric conditions. Considering the large number of SO2 point sources in North America, our results imply that CO2 uptake by the boreal forest in the vicinity of these sources may be lower than previously thought.     

A tale of ‘fat cats’ and ‘stupid activists’: contested values,governance and reflexivity in the brno railway station controversy

ABSTRACT

The article explores one of the biggest controversies over sustainability in modern Czech history, a protracted conflict over whether the Brno railway station should be re-built in a new location. By examining the language of the interaction between a ‘modernizing discourse’ and a ‘sustainability discourse’, the article highlights reflexivity as analytic enterprise that bares the governance dimension of policy conflicts. The reflexive analysis focuses on how actors justify their positions, how they distinguish themselves from their opponents and how they express trust in their own group. It reveals that both discourses are not only related to the re-location issue per se, but that they entail contested notions of legitimate knowledge and modes of governance. Since such power contest is common in sustainability controversies, the reflexive analysis suggests a novel analytical agenda for addressing policy conflicts in sustainability issues.