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最先接触蜜蜂是很小的时候。那时经常跑到花中捕捉蜜蜂玩,被蜂螫后就有点害怕。上学后课文中出现"勤劳的蜜蜂"这一词,更深的了解不多,印象中只保留着"勤劳"、"甜甜的蜂蜜"等,关于蜜蜂的奥秘就更没有探索。于是,今年的选修课我选择 相似文献
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蜜蜂体上的电荷(能)功能加上机械作用,是蜜蜂高效性采集花粉和大量携带花粉而不易脱落的奥秘。蜜蜂对植物的多次重复、及时、足量的花粉授粉,大大强化了"花粉群体效应"和授精作用的选择性,显著提高了授精率、结实率、子实增重率。蜜蜂与植物构成的互惠生态模式,是蜜蜂授粉增产的生物学、生态学基础。 相似文献
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俗话说"燕来兴,蜂来富",我国农村群众自古以来都有养蜂的习惯,把飞来的蜜蜂视为财富临家。蜜蜂确实也是一种"天财",它为我们人类带来了太多太多的财富,发展养蜂、保护蜜蜂,是我们大家共同的责任。 相似文献
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正"蜂疗"是利用蜜蜂和它的产品为人们进行养生和医疗保健的一门颇具特点的学科,称为蜜蜂医疗学,简称"蜂疗"。人类从野生蜂群和家养蜂群中获取蜂产品时,难免遭受蜂蜇。蜂蜇会使人体出现局部或者全身反应,有时也可治愈了多种慢性疾病。蜂疗是经过实践验证的治疗疾病的方法,一直在民间流传。《五十病方》、《神农本草经》和《本草纲目》及藏、傣等少数民族的古代医书都大量记载了利用蜜蜂及其产品进行治疗保健的验方。黄帝内经中有"生病与内其治宜毒药"的治疗原则,俗称"以毒攻毒"。我国是养蜂大国,应该发展蜂疗技术为人类健康做出贡献。人们常说蜜蜂是人类的"药剂师",蜂毒对疾病具有广谱的治疗效果。鉴于某些化学合成药品对 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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Fractures of the anconeal process of 5 pigs ranging in age from 4 to 8 months were studied radiographically and histologically. Clinically, animals with a fracture of the anconeal process had a "tight," restricted gait. In pigs at 4.5 months of age, a radiolucent line through the base of the anconeal process was composed of fibrocartilage, fibrous connective tissue, and hyaline cartilage. Subperiosteal proliferation of woven bone was located along the cranial surface of the olecranon, adjacent to the base of the anconeal process. In older animals, the radiolucent line through the anconeal process contained variable amounts of fibrous connective tissue and fibrocartilage. The proliferation of subperiosteal bone at the base of the anconeal process formed a "buttress callus" which retained a radiolucent area between the callus and the proximal surface of the anconeal process. The latter region of radiolucency was continuous with the transversely oriented line that traversed the base of the anconeal process. 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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家兔作为一种实验动物 ,推动了繁殖技术的发展。本试验通过对不同年龄公獭兔的睾丸进行组织学观察、测定 ,研究精子的发生规律 ,为系统地进行繁殖生理工作提供依据。1 材料与方法选 60日龄、75日龄、90日龄 3个年龄公獭兔各5只 ,用外科手术法摘取两侧睾丸 ,放入 Bouin氏液中固定 ,二甲苯透明 ,石蜡包埋 ,切成 5~ 8μm切片 ,H.E.染色。在显微镜下观察 ,并进行定量组织学指标测定及差异性比较。2 结果和讨论2 .1 睾丸定量组织学指标的测定结果 见表 1。表 1 獭兔睾丸定量组织学指标 μm,个 /精细管60日龄 75日龄 90日龄曲细精管… 相似文献
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以国际标准强毒R株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离MG,并收集感染鸡所产蛋分离MG。结果表明,人工感染48小时后上、下呼吸道及肺已被全面感染,96小时气囊已被感染,120小时输卵管已能分离到MG,卵巢始终分离不到MG。人工感染鸡自144小时便能在其所产蛋中分离出MG。药物治疗能在72小时内消除感染,油乳剂苗则需24天后逐渐降低蛋内MG分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内MG,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
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蚕桑业是跨动、植物两大领域,生产链条长的产业,具有劳动密集型的特征。中国拥有悠久的种桑养蚕历史,灿烂辉煌的丝绸文化、加上成熟的生产技术以及丰富的劳动力资源,因而中国在世界茧丝绸市场上具有巨大的比较优势。茧丝绸产业也是中国在国际贸易中唯一具有市场控制能力的产业。我国加入WTO之后,由于贸易条件 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献