Survival and inactivation of classical swine fever virus   总被引：2，自引：0，他引：2  

Edwards S 《Veterinary microbiology》2000,73(2-3):175-181

Classical swine fever virus, like many enveloped viruses, may be regarded as moderately fragile. It shows a short but variable survival time in the environment, depending on physical conditions, but may remain viable for prolonged periods in favourable circumstances as found, for example, in stored meat. Published information is reviewed on the survival time of the virus under a variety of physical and chemical conditions, including the variable influence of environmental factors. The principles of virus inactivation by heat, pH or chemicals are discussed, with a consideration of the principles of containment for laboratories working with the virus.  相似文献   

仔猪的饲养管理策略     

Joel De Rouchey  Mike Tokach  Steve Dritz  彭慧珍  李丽立 《湖南畜牧兽医》2006,(1):25-27

1 前言一个成功的仔猪营养方案的基本准则是： (1)开饲体重尽可能高： (2)尽可能饲喂简单的日粮； (3)着重于幼畜的饲养管理。我们不能忽视猪的初生体重、年龄、饲养管理质量对于整个饲养过程影响的重要性。  相似文献   

Sustainable management of the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), in infested areas: experiences in Italy, Hungary and the USA     

M. Boriani  M. Agosti  J. Kiss  C. R. Edwards 《EPPO Bulletin》2006,36(3):531-537

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is the most important pest of maize in the Midwestern USA, and since its detection in 1992 in Europe, also in several countries of Central and Eastern Europe. Methods for managing this pest vary from region to region, depending upon: the different cultural practices in maize production, climatic conditions, soil types, pest behaviour, infestation level and socio-economic conditions. Factors including date of planting, amount of rotated or continuous maize, irrigation, date of rootworm hatching and differences in behaviour of the pest, necessitate developing different management strategies in different areas of the infested countries. Pest monitoring, damage evaluation, threshold development, use of insecticides, risk estimation and crop rotation are some of the starting points in the development of management strategies. Approaches and experiences in D. v. virgifera control and management in Italy, Hungary and the USA, based on the understanding of local agro-ecosystems and socio-economic conditions, are reported.  相似文献   

Comparison of the Sensitivity of Landscape-fire-succession Models to Variation in Terrain, Fuel Pattern, Climate and Weather   总被引：1，自引：0，他引：1  

Geoffrey J. Cary  Robert E. Keane  Robert H. Gardner  Sandra Lavorel  Mike D. Flannigan  Ian D. Davies  Chao Li  James M. Lenihan  T. Scott Rupp  Florent Mouillot 《Landscape Ecology》2006,21(1):121-137

The purpose of this study was to compare the sensitivity of modelled area burned to environmental factors across a range of independently-developed landscape-fire-succession models. The sensitivity of area burned to variation in four factors, namely terrain (flat, undulating and mountainous), fuel pattern (finely and coarsely clumped), climate (observed, warmer & wetter, and warmer & drier) and weather (year-to-year variability) was determined for four existing landscape-fire-succession models (EMBYR, FIRESCAPE, LANDSUM and SEM-LAND) and a new model implemented in the LAMOS modelling shell (LAMOS(DS)). Sensitivity was measured as the variance in area burned explained by each of the four factors, and all of the interactions amongst them, in a standard generalised linear modelling analysis. Modelled area burned was most sensitive to climate and variation in weather, with four models sensitive to each of these factors and three models sensitive to their interaction. Models generally exhibited a trend of increasing area burned from observed, through warmer and wetter, to warmer and drier climates with a 23-fold increase in area burned, on average, from the observed to the warmer, drier climate. Area burned was sensitive to terrain for FIRESCAPE and fuel pattern for EMBYR. These results demonstrate that the models are generally more sensitive to variation in climate and weather as compared with terrain complexity and fuel pattern, although the sensitivity to these latter factors in a small number of models demonstrates the importance of representing key processes. The models that represented fire ignition and spread in a relatively complex fashion were more sensitive to changes in all four factors because they explicitly simulate the processes that link these factors to area burned. The US Government's and the Canadian Government's right to retain a non-exclusive, royalty-free license is acknowledged  相似文献   

Introductory Mycology – a MycoAlbum CD - by G. L. Barron     

Mike Hale 《Plant pathology》2007,56(3):547-547

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The Knockdown Resistance (kdr) Mutation in Pyrethroid-Resistant German Cockroaches     

Ke Dong  Steven M. Valles  Mike E. Scharf  Brian Zeichner  Gary W. Bennett 《Pesticide biochemistry and physiology》1998,60(3):195

A point mutation in thepara-homologous sodium channel gene has been shown to be associated with knockdown resistance (kdr) in several insect species including the German cockroach. In this study, we analyzed the genomic organization of the region where thekdrmutation resides and then performed polymerase chain reaction (PCR) and sequencing using genomic DNA as the template to detectkdrmutation in 24 pyrethroid-resistant German cockroach strains, most of which have been collected recently from the field. Thekdrmutation, G to C at nt 2979 resulting in a leucine to phenylalanine amino acid substitution, was detected in 20 strains including 2 strains from overseas (China and Germany). Our results clearly indicate that thekdrmutation is widespread in German cockroach populations. However, the super-kdrmutation detected in super-kdrhouse flies was not found in any of the 4 strains that showed higher levels of knockdown resistance. Little correlation was observed between the presence of thekdrmutation and the level of knockdown resistance, suggesting the existence of multiple resistance mechanisms in many of these strains.  相似文献   

THE MARINE BIOLOGFICAL STATION OF THE UNIVERSITY OF TEXAS     

Edwards CL 《Science (New York, N.Y.)》1893,21(538):284-285

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Rhizosphere micro-organisms of seminal and nodal roots of wheat grown in pots     

K. Sivasithamparam  C.A. Parker  C.S. Edwards 《Soil biology & biochemistry》1979,11(2):155-160

Wheat grown in Gabalong soil was examined for the microflora of its seminal and nodal root systems of similar age. At all stages of sampling, the seminal roots were found to support a significantly-larger population of bacteria, actinomycetes and fungi in their rhizosphere than the nodal roots. The seminal roots had higher numbers of bacteria and actinomycetes in their residues, but fungal numbers were not significantly different. The “rhizosphere effects” of the two root systems, in the combined analysis, were significantly different only for fungi. An interesting trend on both root systems was that while the numbers of bacteria, actinomycetes and fungi in the rhizosphere decreased with root age, their numbers in the residue increased with age.  相似文献   

Soil S availability in upland pastures of NE Scotland: relationship of extractable soil S and soil respiration to soil and site characteristics     

D. Donald  S.J. Chapman  A.C. Edwards  D. Atkinson 《Soil Use and Management》1999,15(4):213-220

Abstract. The mean extractable sulphur (S) concentration in 315 upland topsoil samples collected in 1988/89 from beneath pasture in NE Scotland was 13 μg S g⁻¹ (range 2–77 μg S g⁻¹). More than two thirds of the samples had S concentrations less than that acceptable for productive soils. Continued decreases in atmospheric S inputs may have increased this proportion subsequently. The analysis of herbage S also indicated that two-thirds of the samples were below 0.2% S. A 'respirometric index', namely CO₂ produced during cellulose decomposition without added S as a percentage of that produced with added S, was significantly less than 100% in a quarter of the soils. Results of three different extraction procedures suggested that sulphate in the soils was present mainly as free plus adsorbed rather than precipitated forms. Soil extraction identified a significant non-sulphate S fraction, presumably organic S. The variability in extractable S stemmed from a combination of geographical, depositional and local site and soil factors. Extractable S was significantly correlated with soil organic matter content and inversely with soil pH and together these factors explained 37% of the variability. While significant differences in mean concentrations between geographical area, soil association and drainage status were evident, no trends could be observed between the major soil subgroups or with altitude.  相似文献   

肉种鸡的营养管理   总被引：1，自引：1，他引：0  

Mike Wineland 《中国家禽》2009,31(16)

肉仔鸡对饲料的适应性比较强,原因之一就是肉仔鸡食欲极强,所以饲喂不同的日粮对胴体的影响不是太大. 而对肉种鸡的饲养来说,情况就完全不一样了,因为肉种鸡在管理中要限饲.要让肉种鸡的生产力达到最大,特别要关注营养成分的摄入量,对肉种鸡采用的限饲,这本身就是个很大的应激,所以说,肉种鸡对疾病以及逆境也很敏感.  相似文献