Sublethal impact of paraquat on the life span and parasitic behavior of Diaeretiella rapae M’Intosh

This study focuses on assessing the impact of sublethal doses of paraquat on the survival, the emergence, the life span and the parasitic behavior of Diaeretiella rapae M’Intosh (Hymenoptera: Braconidae). The impact of sublethal doses was measured at room temperature using different densities of the cabbage aphid Brevicoryne brassicae. The results reveal that the field dose of paraquat caused 100% mortality in D. rapae. The percentage emergence of D. rapae decreased from 80.5% in the control group to 71.5% when treated with the lowest concentration of paraquat. Similarly, the life span of parasitoids that emerged from the mummy treated with paraquat also decreased significantly. Oviposition capability and ovipositor thrusting frequency of D. rapae also treated with sublethal dose paraquat decreased significantly along with a shortened patch residence time in the foraging area.     

基于可信性测度理论的装配式建筑施工过程风险性评估

为降低装配式建筑施工过程安全事故的发生率,保障装配式建筑施工过程的安全,针对我国当前装配式建筑施工过程的特点,结合实地调研及专家咨询,构建了基于结构熵权-可信性测度理论的装配式建筑施工过程的风险性评估模型,并将该模型应用于5个工程实例中,取得了良好的效果。结果表明,该模型是结构熵权与可信性测度理论的有机结合,为客观评估装配式建筑施工过程安全风险性并有效控制施工过程的安全风险提供了新的思路。     

Effects of environmental parameters on the oxygen consumption of four marine invertebrates: a comparative factorial study

The oxygen consumption curves of two decapod crustaceans (Palaemon serratus, Penaeus monodon) and two prosobranch molluscs (Trunculariopsis trunculus, Nassarius mutabilis) have been detected in the entire pO₂ interval from 0 to 160 mmHg, under different conditions of temperature and salinity. From the experimental curves, physiological parameters such as the initial oxygen consumption velocity, the Q ₁₀ values and the oxygen independence indices have been measured. The latter parameters have been obtained using normalised plots which allow their better evaluation. The effects of temperature, salinity and oxygen partial pressure on the oxygen-consumption features have been studied using a factorial experimental plan which allows measurement of the effects of each experimental variable as well as the effects of synergistic interactions between different variables. Received: 27 March 2000 / Accepted: 13 November 2000     

土壤中三聚氰胺的降解动态与两种蔬菜的吸收效应研究

以青菜和马铃薯为供试蔬菜,在建立蔬菜中三聚氰胺液相色谱串联质谱(LC-MS-MS)测定方法的基础上,采用N15同位素稀释法,通过在土壤中添加三聚氰胺进行盆栽试验,研究了三聚氰胺在土壤中的降解动态及两种蔬菜的吸收效应.结果表明,土壤中三聚氰胺降解速率随着土壤中三聚氰胺质量比的增加而变慢,20d以后,降解曲线平缓,速度缓慢,残留时间延长,其降解动态符合Logistic方程.同位素稀释法证实两种蔬菜均可以吸收土壤中的三聚氰胺.当土壤中含有50 mg/kg和100 mg/kg三聚氰胺时,马铃薯的吸收量分别比青菜高4.4和2.1倍.青菜根部对三聚氰胺的吸收高于茎叶.高质量比三聚氰胺对蔬菜生长具有明显的抑制效应.     

Liquid household hazardous wastes in the United States: Identification,disposal, and management plan

Present methods of disposal of today's hazardous household chemicals in the United States are frequently not acceptable because of pathways to groundwater, surface water, and the atmosphere. This report identifies potentially hazardous liquid waste in the household, notes current disposal practices, and recommends an improved management plan that utilizes consumer education, manufacturer cooperation, and governmental intervention. Laws requiring uniform disposal labeling on packaging are critical. Local, county, and state governments must be encouraged to coordinate the necessary infrastructure. Managing hazardous household wastes now will mitigate potential disposal problems.     

Results from Three Field Tracer Experiments on the Neighbourhood Scale in the City of Birmingham UK

The physical processes governing flow and pollutantdispersion at the neighbourhood scale, a spatial scaleintermediate between the street scale and the city scale, is notwell understood. Furthermore, it is not clear whether a traditional approach using averaged characteristics such as theaerodynamic roughness length is sufficient to predict the concentration field at this scale. To investigate pollutant dispersion in a real urban area, three field experiments were designed within the UK-URGENT programme sponsored by NERC. Theexperiments were performed in the City of Birmingham using a finite duration release of inert, non-toxic and non-depositingtracers, vis. perfluoromethylcyclohexane (PMCH) and perfluoromethylcyclopentane (PMCP). Measurements were taken using air bag samplers placedin an arc at 3.5 km (first experiment) and 1 km (second andthird experiments) from the source; some trap samplers wereplaced outside the main arc in the outskirts of the city. Measurements were analysed in the laboratory using anovel gas-chromatography technique. Data so obtained werecompared with predictions from a simple steady-state modeland a time-dependent model. The concentration-time serieswere very asymmetrical with a sharp rise, a plateau followedby a relatively slow decrease and finally a long-livedplateau above (or possibly very slow decrease to) thebackground level.     

Natural resources dynamics: Exhaustible and renewable resources,and the rate of technical substitution

In this paper we study both exhaustible and renewable resources in an endogenous growth model. In particular, we consider the hypotheses in which the rate of technical substitution (RTS) between those two inputs is or is not equal to one. Moreover, we depart from a basic theoretical framework to account for the negative externality constituted by waste accumulation. Finally, a comparative analysis is made between Pigouvian tax and waste recycling, as an environmental policy to correct market failure represented by refuse accumulation.     

137Cs contamination in tea and yerba mate in South America

Gamma-ray spectra from more than 50 samples of food products available in stores of Buenos Aires city were measured using a germanium detector. Activity concentrations of 137Cs up to 10 Bq/kg were found in tea and yerba mate manufactured in Apóstoles, Argentina. Further measurements of tea leaves, yerba mate leaves and soils, all coming from a cultivated area in that region, also show the presence of 137Cs contamination. The results suggest that the area was fertilized with a product that originated in a region affected by the fallout from the Chernobyl nuclear plant accident.     

Air bag effectiveness as function of impact speed

An investigation was conducted to estimate the effectiveness of air bags as a function of velocity. The study consisted of three parts: a theoretical idealization, an analysis of National Automotive Sampling System/Crashworthiness Data System (NASS/CDS), and a reanalysis of previously published Fatality Analysis Reporting System (FARS) data. The theoretical analysis looked at idealized risk curves as a function of velocity; assuming that the air bag offers a benefit for both belted and unbelted occupants. Analysis of the NASS/CDS data looked at the effectiveness of air bags as a function of velocity for Maximum Abbreviated Injury Scale (MAIS) 3+ injuries. The reanalysis of the previously published FARS data looked at the effectiveness of the air bag as a function of velocity for fatalities. The theoretical analysis indicates that the air bag effectiveness should be greatest at the low velocities. The field data analysis of both NASS/CDS and FARS were consistent with the theoretical analysis, indicating that air bags are most effective at the lower velocities, below 40 kph (25 mph), for both belted and unbelted occupants. Although it was not possible to estimate a different effect for belted and unbelted for fatalities using FARS, it was possible for MAIS 3+ using NASS/CDS. For unbelted occupants the effectiveness goes to zero or becomes negative above 40 kph (25 mph) for MAIS 3+, and for belted occupants the effectiveness stays positive but with significantly lower magnitude for speeds above 40 kph (25 mph).     

Assessment of older drivers: relationships among on-road errors, medical conditions and test outcome

PROBLEM: It is essential that driver licensing authorities have a valid and reliable system for evaluating older drivers' continuing competency; road tests are usually required as part of such a system. This study sought to find information about the nature of driving errors made during license review tests, and about relationships between error type and test outcome for older drivers. METHOD: Data from licensing authority files from 533 road tests during a 12-month period were analyzed; medical and other referral information was included. Average driver age was 76 years. Performance scores were generated for intersection negotiation, lane changing, low speed manoeuvres, positioning and speed control, safety margin, and car control. RESULTS: Logistic regression analysis showed that test outcome was well predicted by a subset of driving performance scores; adding driver age to the model explained very little variance. Age alone was strongly associated with outcome. Relationships between referral information and test outcome are also reported. IMPACT: Results highlight several factors relevant to the development of more valid and reliable road tests for older drivers.