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Herbarium plants were used as a material to study possible long-term changes in mineral elements of forest plants. Plants from South Norway collected in the period 1870 to 1930 were compared to plants collected in 1982. Relative to mineral contents in plants from 1870 to 1930, the 1982 material showed elevated levels of Zn, Cd, Rb, K, Mn and Ti and decreased levels of Sr, B, Ca and Mo in some of the plant species analysed. Most of these differences may be explained by changes in the environmental conditions, due to differences in chemical composition of precipitation, accelerated soil acidification and subsequent increasing mineral weathering. Consequently analysis of herbarium plants seems to provide valuable information about preindustrial levels of mineral elements and seems to detect changes in mineral elements brought about by recent anthropogenic activity.  相似文献   
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To assess contaminant concentrations in the Firth of Clyde in relation to the former sewage sludge dump site at Garroch Head, and investigate any temporal changes, fish have been sampled annually since 1992 and sediment since 1999. In addition, a further four locations in the Clyde (Holy Loch, Hunterston, Skelmorlie and Irvine Bay) have been sampled for fish and sediment since 1999. Chlorobiphenyls (CBs) were measured in fish samples and polycyclic aromatic hydrocarbons (PAHs) and CBs in sediment. Since sampling was initiated the concentration for the summation operatorICES7 CBs in fish liver has been consistently >500 microg kg(-1) lipid weight at Garroch Head and the other Clyde sites and lower at the reference sites (Pladda, Colonsay, Broad Bay). Although the lowest CB concentrations of the eleven year period in plaice liver from Garroch Head were found in 2002, CB concentrations were found not to have decreased significantly since sewage sludge dumping ceased in 1998. However, a change in CB profile was observed with fish liver collected between 1992 and 1998 from Garroch Head showing a lower proportion of the less chlorinated CBs compared to the 1999-2002 liver samples. Highest CB and PAH concentrations in sediment were found at Garroch Head and Holy Loch with concentrations at these sites being significantly higher than at all other sites.  相似文献   
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Hurler's disease was excluded in a fetus at 23 weeks' gestation by demonstrating normal iduronidase activity in fetal leucocytes following failure of amniotic cell culture after amnic-centesis at 16 and 19 weeks' gestation. The diagnosis was confirmed in the neonate.  相似文献   
6.
The natural desire for couples to be parents and the medical practitioner's inability to treat most genetic diseases have been responsible for some of the most exciting research into infertility and genetic disorders. This has led in the United Kingdom to the establishment of the Warnock Committee of Inquiry into Human Fertilization and its report in 1984, and to a Review of the guidance on Research Use of Fetuses and Fetal Material published in 1989 and known as the Polkinghorne Report. The Warnock Report, among other ethical issues, considers the most fundamental question which has been debated for thousands of years, namely, What is life and when does it begin? More recently, the report has been responsible for new legislation which imposes ethical and legal restrictions on the scientific and medical community. The Polkinghorne Report recommends a voluntary code of practice which is morally and ethically acceptable within our society. We are also fortunate in the U.K. to have a parliamentary structure which allows debate on such important human issues and is prepared to impose ethical restrictions.  相似文献   
7.
Caching or storing surplus prey may reduce the risk of starvation during periods of food deprivation. While this behaviour occurs in a variety of birds and mammals, it is infrequent among invertebrates. However, golden orb-web spiders, Nephila edulis, incorporate a prey cache in their relatively permanent web, which they feed on during periods of food shortage. Heavier spiders significantly reduced weight loss if they were able to access a cache, but lost weight if the cache was removed. The presence or absence of stored prey had no effect on the weight loss of lighter spiders. Furthermore, N. edulis always attacked new prey, irrespective of the number of unprocessed prey in the web. In contrast, females of Argiope keyserlingi, who build a new web every day and do not cache prey, attacked fewer new prey items if some had already been caught. Thus, a necessary preadaptation to the evolution of prey caching in orb-web spiders may be a durable or permanent web, such as that constructed by Nephila.  相似文献   
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Numerous studies have evaluated air quality and greenhouse gas mitigation benefits of biomass energy systems, but the potential environmental impacts associated with large-scale changes in land-use patterns needed to produce energy crops have not been quantified. This paper presents a framework to assess the potential soil, water, and biodiversity impacts that may result from the large-scale production of dedicated energy crops. The framework incorporates producer economic decision models with environmental models to assess changes in land use patterns and to quantify the consequent environmental impacts. Economic and policy issues that will affect decisions to produce energy crops are discussed. The framework is used to evaluate erosion and chemical runoff in two Tennessee regions. The analysis shows that production of dedicated energy crops in place of conventional crops will significantly reduce erosion and chemical runoff.  相似文献   
9.
Industrial, commercial, and domestic levels of formaldehyde exposure range from <0.1 to >5.0 ppm. Irritation of the eyes and upper respiratory tract predominate, and bronchoconstriction is described in case reports. However, pulmonary function and irritant symptoms together have not been assessed over a range of HCHO concentrations in a controlled environment. We investigated dose response in both symptoms and pulmonary function associated with 3-h exposures to 0.0-3.0 ppm HCHO in a controlled environmental chamber. Ten subjects were randomly exposed to 0.0, 0.5, 1.0, and 2.0 ppm HCHO at rest plus 2.0 ppm HCHO with exercise and nine additional subjects were randomly exposed to 0.0,1.0,2.0, and 3.0 ppm HCHO at rest plus 2.0 ppm HCHO with exercise. Significant dose-response relationships in odor and eye irritation were observed (p < 0.05). Nasal flow resistance was increased at 3.0 ppm (p < 0.01), but not at 2.0 ppm HCHO. There were no significant decrements in pulmonary function (FVC, FEV1, FEF25-75%, SGaw) or increases in bronchial reactivity to methacholine (log PD35SGaw) with exposure to 0.5-3.0 ppm HCHO at rest or to 2.0 ppm HCHO with exercise.  相似文献   
10.
The influence of intact (FLT) and photomodified (phFLT) fluoranthene (0.05, 0.5 and 5 μmol l−1) and herbicide Basagran (5, 20, 35 and 50 nmol l−1) on the germination, growth of seedlings and photosynthetic processes in pea plants (Pisum sativum L., cv. Garde) was investigated. The germination was significantly inhibited already by the lowest concentration (0.05 μmol l−1) of FLT and phFLT, while Basagran caused inhibition only in higher concentrations (35 and 50 nmol l−1). The growth of roots was significantly inhibited by higher concentration 5 μmol l−1 of both FLT and phFLT and the shoot of seedlings was significantly influenced only by photomodified form. The length of root and shoot was inhibited already by concentration 5 nmol l−1 of Basagran. Organic compounds applied on chloroplasts suspension influenced primary photochemical processes of photosynthesis. In chlorophyll fluorescence parameters, the significant increase of F0 values and the decrease of FV/FM and ΦII values by application of FLT (0.5 and 5 μmol l−1) and phFLT (0.05, 0.5 and 5 μmol l−1) was recorded. The maximum capacity of PSII (FV/FM) was influenced by the highest (50 nmol l−1) and the effective quantum yield of PSII (ΦII) already by the lowest (5 nmol l−1) concentration of Basagran. Hill reaction activity decreased and was significantly inhibited by higher concentration (0.5 and 5 μmol l−1) of FLT and phFLT and already by the lowest concentration (5 nmol l−1) of Basagran.  相似文献   
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