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71.
72.
The article reviews the current state of knowledge of noise and how people respond to noise. Sources of community noise are discussed and existing federal legislation pertaining to noise is mentioned. Methods of reducing the noise impact on communities from aircraft, surface transportation, and industrial sites are presented. Interior noise in industry, OSHA noise standards and means of controlling the noise to minimize hearing impairment are emphasized.  相似文献   
73.
Thermal destruction capacity for commercial hazardous waste in the United States is examined to determine current and future capacity requirements. This study focuses on commercial incinerators and cement kilns burning conventional hazardous wastes. Aggregate maximum and available capacity estimates are derived using the most recent information. On a national basis, available capacity far exceeds present demand. On a regional basis, capacity appears sufficient with the exception of the California area. However, this shortfall appears insignificant given the overall capacity situation. While incineration demand may increase for solids and sludges as a consequence of Land Ban disposal restrictions and other reasons, capacity for these wastes again appears sufficient to meet current and projected demands. Thus, arguments that additional commercial incineration capacity will be needed to accommodate an expected increase in incinerable hazardous waste cannot be supported by the available information. The analysis raises concerns about the determination of realistic capacity estimates, and the lack of interaction between the capacity assurance process that documents the need for capacity and state siting processes for new waste management facilities. The excess incineration capacity shown in this paper will contribute to the successful implementation of EPA’s goal to reduce national capacity.  相似文献   
74.
The acoustic behaviour of Eptesicus serotinus was investigated in the field using a 13.5-m vertical, linear microphone array that allowed for simultaneous recordings at three different heights and for the calculation of flight altitude and distance from the array. Recordings were made at two locations that differed in bat species diversity. E. serotinus hunted on average at an altitude of 10.7 m (±2.7) at one location and 6.8 m (±3.6) at the other location. Search signals were 5–17 ms long depending on flight altitude, and consisted of two to three frequency-modulated harmonics. For bats flying below 8–10 m altitude, signal duration decreased with decreasing flight altitude, whereas signal interval, terminal frequency, peak frequency and frequency range of the first harmonic increased. Above 8–10 m flight altitude, the signal parameters were fairly constant. The –10 dB bandwidth and duty cycle did not change with flight altitude. Source levels were calculated to between 121 and 125 dB peSPL re 20 μPa at 10 cm. For bats flying higher than 9 m, the microphone placed 1.5 m above the ground recorded significantly reduced signal durations and frequency ranges of the first harmonic compared to the same signals recorded with the microphones at heights of 7 or 15 m. We caution the use of ground recordings to fully describe the echolocation signals of high-flying bats. We demonstrate that flight altitude significantly influences the structure of sonar signals from E. serotinus. Received: 17 May 1999 / Received in revised form: 20 September 1999 / Accepted: 25 September 1999  相似文献   
75.
76.
Halogenated flame retardants have a high sorption affinity to particles, making soils and sediments important sinks. Here, three of the most commonly used flame retardants have been tested for sub-lethal toxicity towards soil nitrifying bacteria, a terrestrial plant (seed emergence and growth of the red clover, Trifolium pratense), and a soil invertebrate (survival and reproduction of Enchytraeus crypticus). Tetrabromobisphenol A (TBBPA) was quite toxic to enchytraeids, with significant effects on reproduction detected already at the 10 mgkg(-1) exposure level (EC(10)=2.7 mgkg(-1)). In contrast, decabromodiphenyl ether (DeBDE) was not toxic at all, and short-chain chloroparaffins (CP(10-13)) only affected soil nitrifying bacteria at the highest test concentration (EC(10)=570 mgkg(-1)). Exposure concentrations were verified by chemical analysis for TBBPA and DeBDE, but not for CP(10-13), as a reliable method was not available. Based on the generated data, a PNEC for soil organisms can be estimated at 0.3 mgkg(-1) for TBBPA and 57 mgkg(-1) for short-chain chloroparaffins. No PNEC could be estimated for DeBDE. Measurements of TBBPA in soil are not available, but measured concentrations in Swedish sludge are all lower than the estimated threshold value for biological effects in soil.  相似文献   
77.
This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions.  相似文献   
78.
动物行为是动物福利的核心部分,是可持续的动物育种的基础.在驯化过程中,动物已在行为和一系列其它显著特性方面产生适应性.我们对原鸡和白莱亨蛋鸡(为产蛋而选,间接为产肉而选)的行为进行了比较.原鸡在群居、探索、抗捕食和进食试验方面表现出更积极的行为.对一只原鸡与白莱亨鸡杂交后代进行的定量特性位点(QTLs)基因组扫描显示,不同的特性具有一些明显的或启示性的QTLs.一些生产QTLs与行为QTLs相重合,表明生物多向性效应对育种显型的发展也许是重要的.我们定位了一种基因,它对成为啄毛行为受害者方面有强烈影响,而啄毛是一种有害的行为紊乱现象.现代基因学配以行为分析,也许有益于未来设计出更加可持续的育种方式,培育出耐力更强的动物.  相似文献   
79.
Fly ashes fiom lignite coal fixed steam electric plants contain appreciable amounts of materials that can, in principle, decrease the phosphorus concentration in surface waters. Typical samples of un-weathered fly ash were used to test efficacies of removal of phosphorus from standard phosphate solutions and actual lake water samples. The effects of changing parameters such as contact time, pH, fly ash/water ratios, and solution temperature are presented. Water soluble and insoluble factors in the ash both appear to be reactive constituents. Trials with municipal waste waters showed near quantitative removal of ortho-phosphate.  相似文献   
80.
A mathematical model widely applied in population studies and in assessment of the impact of exploitation on fish populations was applied to assess cadmium toxicity in laboratory populations ofDaphnia galeata mendotae. Over a range of toxicant concentrations, the birth rate of the population increased to balance the death rate and the population compensated for the increased mortality. The model describes the relation between toxicant concentration, toxicant-induced mortality, and equilibrium population size. Compensation for increased mortality is described in terms of the decrease in population size necessary to produce an increase in the birth rate that will balance the increased death rate. The relative capacity of different aquatic organisms to compensate for toxicant-induced mortality is examined and a relation between compensatory capacity and the innate capacity for increase is developed.  相似文献   
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