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影响水稻轴流脱粒与分离装置性能指标的因素很多,并且它们之间存在着复杂的非线性关系,用传统方法很难对其进行准确预测。神经网络算法简单、学习收敛速度快、具有线性、非线性逼近精度高等特性。本文以正交旋转组合实验获得的数据作为样本,对人工神经网络(ANN)模型进行训练学习,利用训练后所得到的模型,对性能指标进行了预测。结果表明,网络预测值与实测值之间具有很高的相关性和精确度,为机械性能指标研究提供了一定的理论辅助手段。 相似文献
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In this study, the possible influence of temperature on infectious pancreatic necrosis virus (IPNV)-induced apoptosis in a zebrafish liver epithelium (ZLE) cell line was investigated. At a lower temperature (18 degrees C), there was expression of viral proteins VP2 and VP3 at 4 h post-infection (p.i.). At this time no expression was found in the high temperature group at 28 degrees C. The cell survival ratio was 52 and 18% at 24 and 48 h p.i., respectively, during IPNV infection at 18 degrees C. In addition, we assayed for apoptosis in IPNV-infected cells with terminal deoxynucleotidyl transferase (TdT)-mediated end labelling (TUNEL) of DNA at different dosages of virus. We found a ratio of apoptotic cells of 8 and 25% at 12 and 18 h p.i., respectively, in the multiplicity of infection (MOI) 1 group. The MOI 10 group had 20 and 45% apoptotic cells at 12 and 18 h, respectively. Furthermore, at 18 degrees C IPNV activated the caspase-8 and 3 from 1.5 to 2 times at 12 and 18 h p.i., respectively. Taken together, these findings suggest that successful virus replication occurs at the low temperature (18 degrees C) compared with the non-permissive temperature of 28 degrees C. Thus, IPNV replication is capable of activating caspase-8 and -3 and inducing host apoptosis. 相似文献
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An artificial oyster‐shell reef for the culture and stock enhancement of sea cucumber,Apostichopus japonicus,in shallow seawater 下载免费PDF全文
Libin Zhang Tao Zhang Qinzeng Xu Tianlong Qiu Hongsheng Yang Shilin Liu 《Aquaculture Research》2015,46(9):2260-2269
Because of its high nutritional value and health benefits, aquaculture production of Apostichopus japonicus in China is the largest of any single species. Therefore, the development of new farming methods is of considerable significance. In this study, discarded oyster shells have been used to create an artificial reef for the culture of this species. The results have shown that from 6th March 2009 to 26th November 2009, the wet weight of sea cucumber increased from 49.57 ± 1.16 to 79.87 ± 1.46 g ind?1. Between 16th July and 18th October, the specific growth rate and daily weight gain of A. japonicus differed significantly from other periods. Population density was higher within the reef compared with outside the reef area, and the difference was significant (P < 0.01). The maximum distance between A. japonicus individuals within the reef area on 3rd March and 16th July was 65.0 ± 3.3 and 62.9 ± 4.4 cm, respectively, but the difference was not significant (P > 0.05). The diatom species attached to the oyster shells were similar to those found in the stomach content of A. japonicus. In conclusion, the oyster‐shell reef provides a suitable habitat and shelter for the culture of the sea cucumber, A. japonicus. 相似文献
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从患病香鱼的体腔液中分离获得嗜水气单胞菌病原,经培养稀释的菌液,腹腔注射人工感染健康香鱼,出现典型的出血症后,进行血液生理生化指标的测定。结果发现,病鱼红细胞数量为(1.21±0.08)×1012个/L,血栓细胞数量(189.00±5.19)×1012个/L,较健康香鱼红细胞[(2.41±0.16)×1012个/L]、血栓细胞[(380.0±20.00)×1012个/L]呈极显著降低(P0.01),血红蛋白含量呈显著减少(P0.05),而白细胞数量却显著增加(P0.05)。染病香鱼总蛋白为(47.56±2.63)g/L,健康鱼为(49.23±3.06)g/L,经检验无显著差异;而碱性磷酸酶、Cl-、Ca2+等3项血液生化指标值均呈极显著减少(P0.01),乳酸脱氢酶呈极显著增加(P0.01)。 相似文献
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Atlantic salmon, S almo salar L., were exposed to different concentrations of Paramoeba sp. The lowest concentration which induced amoebic gill disease (AGD) was 230 Paramoeba sp. L–1 and the severity of infection increased with increasing concentration. The concentration of Paramoeba sp. positively correlated with the number of gill lesions ( R 2 > 0.7). This study provides evidence that Paramoeba sp. is the causative agent of AGD and describes an experimental model that enables the severity of the induced disease to be controlled. 相似文献
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红螯螯虾的室内人工育苗 总被引:7,自引:1,他引:7
于1996-1998年,在浙北地区,对澳大利亚引进的红螯螯是进行亲虾培育、人工越冬,怀卵孵化,室内人工育苗技术的研究。研究表明,在浙北地区,2.8-4.9g的幼虾经5个月左右的饲养可以达到性成熟并部分怀卵,利用电厂余热水水泥池人工越冬的成活率可达70%以上。越冬后亲是在水温20℃以上即开始交配怀卵,怀卵盛期4-6月。红螯螯虾一年可产卵4次,但只有第一、二次怀卵可用于育苗生产,个体一次怀卵量较少,一般为400-500粒,但群体怀卵比率较高。试验还表明,红螯螯虾出膜幼体即呈幼虾状,需依附母体7-10d后才营独立生活并开口摄食外源性饵料,所研制的幼虾Ⅰ号饲料为红螯螯虾室内人工育苗较好的开口饲料。室内人工育苗成活率可达60%以上。 相似文献