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261.
上个世纪的环境污染造成了健康问题,土地和湖水的酸化以及对文化遗产的损害.不仅露天的文物受环境污染的影响,地下文物也因此遭受不测.然而到目前为止,我们对地下文物受损状况的研究相当有限,而对这个被忽视的领域给予重视是相当重要的.在此文中,我们将报道在瑞典国家文化遗产委员会得到的有关文物受损的研究结果;这些文物是来自史前墓穴中的青铜器、铁器和骨器考古物品,它们的材料仿佛受到污染的影响最大.对调查时采用的方法作了介绍,并对其它相关的研究做了简要的综述.近年来,历史文物(特别是无机材质的文物)遭受侵蚀的速度已明显加快,而文物侵蚀速度的上升主要归因于人类造成的污染.对于污染可能危及的区域,在文中将举例说明.  相似文献   
262.
Summary Song flight, which is an aerial song display especially used by many open country bird species, is expected to be energetically very costly. Any morphological adaptation reducing the magnitude of this cost thus would be favored by selection. Male skylarks Alauda arvensis perform frequent song flights during a period of nearly half the year. Skylarks are sexually size dimorphic in most body traits, but particularly in wing area and wing span, which is absolutely and relatively larger in males than in females. Wing loadings, aspect ratios, and flight costs therefore are smaller in males than in females. I investigated the effect of wing area and aspect ratio on the duration of the song flights of individual birds by timing their duration before and after an experimental manipulation of wing area. Male skylarks were caught, ringed, and released (control I), had the tips of their wing feathers cut (control II), or had the tips of their wing feathers reduced by approximately 10 mm. There were no statistically significant differences in morphology or duration of songs between treatment groups before experimental treatments. However, males having the tips of their wing feathers reduced by ca. 10 mm performed only greatly abbreviated song flights. Original wing loading and aspect ratio also affected the duration of song flights, since male skylarks with low wing loadings and high aspect ratios performed longer song flights than did males with high wing loadings and low aspect ratios. This was the case both before and after experimental treatment. Wing area is suggested to reflect the ability of individual skylarks to invest in morphological structures allowing an increased song output.  相似文献   
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CCl4, CCl3F and CCl2F2 decompose in ambient air forming highly toxic carbonyl halides etc. when exposed to sources of intense uv-emission, e.g. welding arcs. The resulting health hazard is assessed using a mathematical model.  相似文献   
265.
Landfills generate emissions over long periods, often longer than a lifetime. The longest lasting emission is leachate. In order to estimate the future requirements for leachate treatment, different kinds of leaching tests may be applied. In this paper, shaking leaching tests (SLT), landfill-simulator leaching tests and a field-cell leaching test performed with ash, municipal solid waste (MSW) and MSW+ash are evaluated. The tests are compared and the factors influencing leaching are identified and discussed. The factors are: liquid to solid (L/S) ratio, water withdrawal, recirculation rate, presence or absence of biological processes, size of particles, duration of experiment, temperature and pre-treatment of the waste. The presence of biological processes has the greatest impact on leaching and is the main reason why SLT is less useful for long-term predictions. The landfill simulator tests were found to be useful for several different kinds of predictions. However, they are not reliable for predicting the L/S required for reaching a certain concentration. The possibilities for reliable long-term predictions would be facilitated by a better knowledge of the influence of various factors on leaching. Such an increased knowledge would make it possible to enhance waste stabilisation in leaching tests as well as in full-scale landfills.  相似文献   
266.
A study was undertaken to investigate whether driver celeration (overall mean speed change) behavior can predict traffic accident involvement. Also, to test whether acceleration, deceleration or the combined celeration measure was the better predictor. Bus driver celeration behavior was measured repeatedly in real traffic, driving en route, and correlated with accidents for which the drivers were deemed at least partly responsible. Correlations around .20 were found in several samples between celeration behavior and culpable accidents for a 2-year period. The results show that although celeration behavior is only semi-stable over time, it predicts with some accuracy individual accident involvement over 2 years. The predictive power of acceleration and deceleration was slightly lower than the combined measure, in accordance with theory. The correlations found were strong enough to warrant the use of celeration behavior as a predictive variable for transportation companies in their safety work.  相似文献   
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Genetic modification leads to several important moral issues. Up until now they have mainly been discussed from the viewpoint that only individual living beings, above all animals, are morally considerable. The standpoint that also collective entities such as species belong to the moral sphere have seldom been taken into account in a more thorough way, although it is advocated by several important environmental ethicists. The main purpose of this article is to analyze in more detail than often has been done what the practical consequences of this ethical position would be for the use of genetic engineering on animals and plants. The practical consequences of the holistic standpoint (focused on collective entities) of Holmes Rolston, III, is compared with the practical consequences of the individualistic standpoints (focused on individual living beings) of Bernard E. Rollin and Philipp Balzer, Klaus Peter Rippe, and Peter Schaber, respectively. The article also discusses whether the claim that species are morally considerable is tenable as a foundation for policy decisions on genetic engineering.  相似文献   
270.
A novel technique, gas chromatography-UV spectrometry (GC-UV), was used to quantify volatile organic compounds (VOCs) in settled dust from 389 residences in Sweden. The dust samples were thermally desorbed in an inert atmosphere and evaporated compounds were concentrated by solid phase micro extraction and separated by capillary GC. Eluting compounds were then detected, identified, and quantified using a diode array UV spectrophotometer. Altogether, 28 compounds were quantified in each sample; 24 of these were found in more than 50% of the samples. The compounds found in highest concentrations were saturated aldehydes (C5-C10), furfuryl alcohol, 2,6-di-tert-butyl-4-methylphenol (BHT), 2-furaldehyde, and benzaldehyde. Alkenals were also found, notably 2-butenal (crotonaldehyde), 2-methyl-propenal (methacrolein), hexenal, heptenal, octenal, and nonenal. The concentrations of each of the 28 compounds ranged between two to three orders of magnitude, or even more. These results demonstrate the presence of a number of VOCs in indoor dust, and provide, for the first time, a quantitative determination of these compounds in a larger number of dust samples from residents. The findings also illustrate the potential use of GC-UV for analysing volatile compounds in indoor dust, some of which are potential irritants (to the skin, eyes or respiratory system) if present at higher concentrations. The potential use of GC-UV for improving survey and control of the human exposure to particle-bound irritants and other chemicals is inferred.  相似文献   
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