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961.
Gustafson L Ellis S Robinson T Marenghi F Merrill P Hawkins L Giray C Wagner B 《Journal of fish diseases》2007,30(2):101-109
The distribution of infectious salmon anaemia (ISA) was examined among 80 cages from three Atlantic salmon grow-out farms in Maine, USA that were stocked with smolts from a single hatchery. Cage-level disease was broadly defined as one or more moribund fish testing positive for infectious salmon anaemia virus (ISAV) by RT-PCR and a second confirmatory test (IFAT, culture or genotype sequence). Spatio-temporal and cage-level risks were explored using logistic regression and survival analysis. Non-spatial risk factors associated with ISA, or shortened survival time to disease, included increased predation, trucking company choice for smolt transfers, a finely-sedimented benthic substrate, and smaller average size of smolts at stocking. Univariable analysis identified the time-dependent spatial factor 'adjacency to newly infected cages' to be predictive of new infection in neighbouring cages 11-12 weeks later. However, none of the spatial factors, or their lags retained relevance in multiple-variable models. The results suggest a diffuse distribution of virus exposure throughout infected sites, with host-susceptibility factors probably influencing disease manifestation in individual cages. The narrow focus of the current study may limit application of the findings to other sites and year-classes. However, these data support the relevance of husbandry efforts to optimize fish health in regions affected by ISAV. 相似文献
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T. H. Stobbs 《Grass and Forage Science》1969,24(4):345-348
An experiment is described in which liveweight gains were measured from two grass/legume pastures using small East African Zebu animals and also progeny of small East African Zebu cows crossed with Bos taurus bulls. Significantly higher production was obtained from cross-bred stock, which averaged 706 lb liveweight gain at per annum (791 kg/ha per annum), compared with 509 lb liveweight gain/ac per annum (571 kg/ha per annum) from Zebu stock, indicating that pasture management had advanced beyond the genetic potential of the local Zebu stock. The problems of designing, conducting and interpreting the results of such grazing trials are discussed. 相似文献
964.
A. T. van Schermbeek 《Forstwissenschaftliches Centralblatt》1902,24(3):115-119
Ohne ZusammenfassungKonstruiert vom tönigl. niederländischen Oberförster und Dozent an der höheren Lehranstalt für Land- und Forstwirtchaft. 相似文献
965.
T. 《Forstwissenschaftliches Centralblatt》1898,20(2):66-72
Ohne Zusammenfassung 相似文献
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Shchemelinina T. N. Anchugova E. M. Lapteva E. M. Vasilevich R. S. Markarova M. Yu. Glazacheva E. N. Uspenskaya M. V. 《Eurasian Soil Science》2020,53(2):230-239
Eurasian Soil Science - The results are presented of modeling the “contour water flooding” biotechnology aimed at cleaning heavily petroleum-polluted agrosoddy-podzolic soils (Albic... 相似文献