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Field outbreaks of a syndrome of unknown aetiology associated with the grazing of green oats (Avena sativa) in the south-western Cape Province were characterized by diarrhoea, photosensitivity and death in goats and by diarrhoea and a reduction in milk production in cows. A phytopathogenic fungus, Drechslera campanulata, was isolated from conspicuous reddish-brown leaf spots on oat plants collected from both outbreaks. Pure cultures on autoclaved maize of D. campanulata isolates from oat leaves implicated in both field outbreaks, as well as a Canadian isolate, proved to be highly toxic to ducklings, goats and sheep. Characteristic clinical signs of the fatal mycotoxicosis caused by D. campanulata culture material in goats and sheep were anorexia, apathy, diarrhoea and ruminal stasis. Photosensitivity, however, was not induced. Necrosis of the forestomach mucosa was the most characteristic gross pathological change. Histopathological findings included mild focal erosions to severe, diffuse, coagulative necrosis of the mucosa in the rumen, reticulum and omasum and congestion and haemorrhages in the abomasum. These results provide circumstantial evidence that green oat leaves infected by D. campanulata may cause outbreaks of a mycotoxicosis in grazing animals.  相似文献   
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Zusammenfassung Die Erkenntnis, da? die beste Umweltpolitik darin besteht, Umweltbelastungen von vornherein soweit wie m?glich zu vermeiden, statt sie erst nachtr?glich in ihren Auswirkungen zu bek?mpfen, ist unter dem Eindruck bedrohlicher Eingriffe in das „System Umwelt” unterdessen zum wichtigsten Grundsatzprinzip der Umweltaktions-programme—auch dem der EG—erkl?rt worden. Die praxisbezogene Umsetzung dieses Grundprinzips einer vorausschauenden Umweltplanung setzt allerdings voraus, da? zuerst einmal überhaupt genügend geeignete Informationen über Zustand und Leistungsf?higkeit der Umwelt zur Verfügung stehen und da? darüber hinaus eine entscheidungsorientierte Implementierung dieser Informationen auch tats?chlich erfolgen kann. Beide Voraussetzungen sind heute in der Regel kaum erfüllt. Den Bemühungen der EG, hier einen nicht zuletzt auch stimulierenden Beitrag auf Gemeinschaftsebene zu leisten, sollen vor allem die beiden in Angriff genommenen Gemeinschaftsaktionen „?kologische Kartierung” und „Umweltvertr?glichkeitsprüfung” genügen. Beide Aktionen erg?nzen sich in mancher Hinsicht. Für die Aktion „Umweltvertr?glichkeitsprüfung” ist bereits im Laufe des n?chsten Jahres mit geeigneten Vorschl?gen der EG-Kommission an den EG-Ministerrat zu rechnen. Die „?kologische Kartierung” wird im Rahmen eines mehrj?hrigen Arbeitsplanes in vier Programmphasen abgewickelt. Die erste und methodisch wichtigste Programmphase soll Ende n?chsten Jahres mit dem Billigungsvorschlag einer Pilotmethode an den Rat zwecks sukzessiver Erfassung des gesamten Gebiets der EG abgeschlossen werden.
The prevention of future environmental damage. The European Community is stimulating the development of instruments for a preventive environmental policy
Summary Under the influence of the magnitude of the conflicting influences to which the environmental system is exposed, the recognition that the best environmental policy consists in the prevention as far as possible from the very beginning of environmental pollution, rather than in dealing with its effects after the event, has become the most important basic principle of environmental policy, including the Community's Action Programme. The practical implementation of this principle of preventive environmental planning does, however, depend on the availability of sufficient suitable information on the state and characteristics of the environment and on there existing a mechanism by which this information can be fed into the decision-making process. These preconditions are not usually fulfilled at the present time. The two actions in the fields of “Environmental Impact Assessment” and “Ecological Mapping” represent the main thrust of the Community's efforts to play a catalytic role in this field. The actions are complementary in several respects. It is expected that the Commission will present its first proposals to the EC Council of Ministers on “Environmental Impact Assessment” in the course of the coming year. The “Ecological Mapping” is being developed in a multi-annual work programme, divided into four phases. The first, and methodologically most important phase should end next year with a proposal to the Council to approve a pilot methodology which can be used for the gradual mapping of all Community territory.
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Summary Trembling aspen has been impregnated with the coupling agent -methacryloxypropyltrimethoxysilane and the hygroscopicity and antishrink efficiency measured before and after water extraction. There was a hygroscopicity depression with treatment, but not enough to account for the observed antishrink efficiencies. There was limited reversibility after water extraction. This indicated that the wood was interacting with part of the sorbed silane more strongly than with water, and that there was a diversity of sorption environments within the wood-silane complex.The authors are grateful for financial support by the Natural Sciences and Engineering Research Council of Canada  相似文献   
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Hygroscopicity of wood impregnated with linseed oil   总被引:1,自引:0,他引:1  
Summary The reduction in hygroscopicity as spruce wood is impregnated with linseed oil may be accounted for using a molecular exclusion model. On the basis of the model, each linseed oil molecule appears to displace 90 water molecules and occupy 6 hydrogen bonding sites in the wood.Dr. Allen R. Sharp, Associate Professor of Physics at the University of New Brunswick and Dr. Christen Skaar, Professor of Wood Physics at Virginia Polytechnic Institute and State University freely gave essential advice and encouragement during this work. Graphical depiction of the molecular displacement model (Fig. 1) was suggested by Dr. Skaar. Much of the experimental work was carried out by Mr. Wu-Rong Perng, Scientific Technician in Wood Science and Mrs. Monica Snow, Instructor in Wood Science at the University of New Brunswick  相似文献   
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In this study, lipid classes and fatty acid composition were determinedin eggs of P. vannamei as a function of survival to zoeaIII stage. Spawns were reared individually to zoea III and grouped, accordingtotheir final survival to this larval stage, into spawns of high and lowsurvival.Eggs of individual spawns were analyzed for lipid and fatty acid composition ofneutral and polar lipids and the results were then grouped according tosurvivalto zoea III. The lipids within each group (high and low survival to zoea III)were pooled for the separation of phospholipids and the analysis of their fattyacid composition.Higher levels of triglycerides, carotenoids, and linoleic (18:2n-6) acid ineggs were associated with improved survival to zoea III. Linoleic acid washigher in spawns from the high survival group in both neutral and polarfractions and in most of the phospholipid classes analyzed. Docosahexanoic acid(DHA) was not related to survival to zoea, probably because its content washighenough (> 15% of total fatty acids) to satisfy embryo and early larvaldevelopment needs. A high content of eicosapentaenoic acid (EPA) was found inphosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylserine, andphosphatidylinositol compared to other phospholipid classes, suggesting aspecific role of EPA in these lipids. These results describe the specificphospholipid composition of penaeid eggs and could (potentially) be used aspredictive indicators of larval quality for research and production purposes.  相似文献   
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