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M. J. Toerien 《African Zoology》2013,48(1):105-110
Cliff-nesting pale-winged starlings (Onychognathus nabouroup) gather on the cliff tops to perform Group Displays which include both aggressive and courtship elements: Hopping, Wing Stretching, Wing Drooping, Wing Flicking, Staring, Head Forward Threat and Butterfly Fluttering. These displays occur throughout the year, most frequently in the late afternoon. We suggest that this behaviour may be important in pair formation, and in establishing dominance relationships between birds breeding at the same site. 相似文献
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The morphology and histology of the digestive tract of the branchiuran crustacean, Chonopeltis australis Box shall, 1976 are described from serial sections. The foregut is differentiated into a preoral cavity, containing the mandibles and tongue, an ascending oesophagus, with an H-shaped lumen invested with longitudinal, circular and dilator muscles, a horizontal oesophagus with a star-shaped lumen and lacking longitudinal and dilator muscles, and an oesophageal funnel consisting of inner and recurrent walls. The midgut is differentiated into anterior and posterior chambers, separated by an S-shaped muscular tube. The arborescent midgut glands open laterally into the anterior part of the anterior midgut. Columnar epithelial cells line the anterior midgut whereas tall, papilliform cells are present in the epithelium of the posterior midgut. The transition from posterior midgut to hindgut is marked by the presence of very tall epithelial cells. The terminology describing the various parts of the digestive tract of branchiurans is discussed. 相似文献
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Comparisons were made of Cortisol concentration and behavioural activity between piglets weaned at 3 weeks of age (early weaned piglets), and piglets weaned at 8 weeks of age (control piglets). Early weaned littermates were placed in cages with a floor area of either 0.20 m2 per piglet or 0.15 m2 per piglet. At 8 weeks of age, the piglets in the control litters were moved from the sow and early weaned piglets were moved from the cages. All litters were placed in pens, 1 pen for each litter. Radioimmunoassay was used for plasma Cortisol determination. Behavioural activity included determination of play, aggressive behaviour and non-nutritive oral activity. Statistical analysis for possible association between plasma Cortisol concentration and age, housing conditions, litter and sequence of capture of littermates for blood collection revealed a complex pattern. Generally, higher plasma Cortisol concentrations and more aggressive and non-nutritive oral activity, but less playing activity, were associated with early weaning. Plasma Cortisol concentration in individual piglets was positively correlated to both aggressive and non-nutritive oral behaviour, but was negatively correlated to playing behaviour. It is concluded that early weaning is a stressor. 相似文献
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蜜蜂生物学与饲养管理技术研究是发展现代养蜂业的重要内容。近年来,世界各国养蜂业从事人员通过不断地探索与实践,在蜜蜂生物学领域取得了大量成果,并研发出了大量新的蜜蜂饲养管理技术和配套设施。对近3年国内外蜜蜂生物学与饲养技术进行综述,为促进我国养蜂业的发展提供借鉴。 相似文献
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转基因技术在农业育种中具有重要地位和作用,对解决资源短缺、粮食危机有重要意义。本文综述了转基因、体细胞克隆以及基因打靶等生物技术的发展历程,及其对转基因育种的促进作用,并简要介绍了我国转基因生物育种重大专项中关于转基因动物育种的情况。 相似文献
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脂质体在医用生物学中的研究与应用 总被引:1,自引:0,他引:1
脂质体作为一种对机体无毒、无免疫原性的定向药物载体,它既能包封脂溶性药物,又能包封水溶性药物;减轻变态反应和免疫反应;延缓释放,延长药物在体内的半衰期;能有效地保护被包裹药物,提高生物利用度;改变药物在体内的分布,并能靶向性释药,降低药物的毒副作用;适合多途径给药等特点。文章论述了脂质体作为药物载体、基因工程载体、疫苗载体、免疫诊断、基因治疗和核酸免疫中的DNA载体等在医用生物学中的研究应用,并扼要介绍了近年来脂质体的最新发展动态,表明了脂质体制剂在医用生物学研究中广阔的应用前景。 相似文献
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The active–inactive model predicts temporal variation in the operational sex ratio (OSR) throughout a breeding season, as a function of each male’s optimal strategy for finding mates. I tested the model using data for the raucous toad, Bufo rangeri, collected nightly over three breeding seasons. The numbers of active males and fertilizable females were correlated in two of the three breeding seasons. The OSR, defined as the average ratio of sexually active males to fertilizable females, decreased throughout each season, except for the first, when it rose to a peak before decreasing. The OSR fluctuated towards the end of the season in two of the three seasons, and rose again at the end in only one. Although the equal-performance assumption was violated, the temporal pattern of the OSR in this species complied largely with that predicted by the active–inactive model. Reasons for deviations from the model’s predictions are discussed. Despite the lack of data on mortality rates, this study represents the most comprehensive test of the model yet, as tests on other species have been based on data collected intermittently, as opposed to nightly, over only two breeding seasons. 相似文献
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集约化猪场猪异常行为的发生原因及防制措施 总被引:2,自引:1,他引:2
随着集约化养猪生产的发展,猪异常行为的发生率有升高趋势,据临床观察和分析,其发生原因主要有环境因素,疾病因素,营养因素,饲养管理因素及猪的心理行为因素等。减少或避免猪异常行为的发生,应根据基发生原因坚持以防为主,防重于治的原则,着重加强饲养管理和养猪环境的改善。 相似文献
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J. D. Skinner 《African Zoology》2013,48(1):75-84
During a detailed study of the South African gannet, Sula capensis, various methods of behaviour analysis were tried. Three methods are outlined in this paper and the results obtained from each method were in general agreement. The significance of the Sky point posture is considered in some detail. 相似文献
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禽流感病毒血凝素糖蛋白(HA)的结构及其生物学功能 总被引:5,自引:0,他引:5
高致病性禽流感 (AI)是由禽流感病毒(AIV)引起的一种急性传染病。AIV呈球形 ,有囊膜。其表面主要有两种糖蛋白 ,其中血凝素(hemagglutinin ,HA)具有重要功能 :能凝集红细胞 ,属I型糖蛋白 ;具有株和亚型的特异性 ,是AIV型和亚型内新变种判断的主要依据 ;能结合宿主唾液酸之类的细胞受体 ;HA在病毒吸附及穿膜过程中起关键作用 ,HA上裂解位点的序列直接影响AI病毒致病性的高低 ;HA的变异性很强 ,它的变异是AI病毒发生抗原变异的主要原因 ,HA是最主要的抗原物质。因此HA对AIV的生物学特征具有十分重要的意义 相似文献
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猪繁殖与呼吸综合征病毒的分子生物学研究进展 总被引:1,自引:0,他引:1
猪繁殖与呼吸综合征是目前养猪业中一种严重的病毒性传染病,引起猪严重繁殖障碍和呼吸道疾病。该病的病原体属于动脉炎病毒属,是一种不分节段的单股正链RNA病毒,含有8 个开放阅读框(ORFs),ORF1 编码非结构蛋白,ORF2~ORF7 编码结构蛋白。其中ORF7 编码的核衣壳(N)蛋白和ORF6编码的非糖基化基质(M)蛋白为优势结构蛋白。猪繁殖与呼吸综合征病毒基因组存在广泛的遗传变异性,M蛋白和N蛋白在所有的毒株之间相对比较保守,可作为血清学诊断的靶抗原。文章就猪繁殖与呼吸综合征病毒在分子生物学方面的研究情况做作一综述。 相似文献
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