首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
杨思林  刘宁  李纯 《安徽农业科学》2011,39(32):19858-19859,19866
[目的]为成功饲养孟加拉虎积累经验。[方法]2005年12月至2006年8月,采用瞬时扫描取样法和全事件取样法,对云南省野生动物园内繁殖期4号雌虎行为的时间分配进行了研究。[结果]繁殖期不同阶段雌虎白昼行为时间分配存在明显差异。发情交配期孟加拉虎的卧息、走动和其他行为多于妊娠期,发情交配期孟加拉虎的睡眠少于妊娠期;哺乳期母虎哺乳所占时间最多,其次是走动和卧息,而睡眠、摄食及其他行为(包括饮水、排尿、排粪、修饰、嗅闻、站立等)最少。[结论]繁殖期不同阶段孟加拉虎的各种行为均有所变化,而行为的变化与雌虎在繁殖期各阶段的特殊生理有关。  相似文献   

2.
赤霉属真菌大多是农业生产上具有破坏性的植物病原真菌。选取几种在农业生产上重要的赤霉属真菌来阐述该属在系统发生,生物学和化学上的多样性,并且比较了它们在分类学、遗传学、植物病理学和真菌毒理学方面的差异。虽然它们是非常近缘的赤霉属各种,但在繁殖方式、地理分布、寄主范围、植物致病机理、毒素和其他生物活性代谢物的产生方面都有所不同。  相似文献   

3.
The content of ovarian, adrenal, and thyroid hormones in the blood of Red Pied cows at various times of pregnancy and in the case of infertility is studied. The characteristics of hormonal interrelations in various nosologically differentiated pathologies of the sex organs are determined. Opinions are expressed about possible ways to normalized their reproductive function.  相似文献   

4.
Comparisons of reproductive behaviors of three age classes of California gulls demonstrate that reproductive effort increases with age in this seabird. These findings contradict the assumption that increased reproductive success with age results from increased experience and social status and demonstrate that selection for increased reproductive effort can occur in long-lived species.  相似文献   

5.
李晓楠  方庆 《安徽农业科学》2016,44(17):130-133
迄今为止,已发现有11种生殖激素参与龟类生殖调控。雌二醇和睾酮在促性腺激素释放激素、卵泡刺激素和黄体生成素的调控下主导调控龟类性腺发育、配子生成、交配、产卵及子代性别决定等重要生殖环节。孕酮、前列腺素、精氨酸催产素、皮质酮、甲状腺素和褪黑激素协同调节龟类生殖活动。在人工繁殖方面,使用GnRH等有助于克服龟类繁殖障碍,提高繁殖效率。对生殖激素对龟类生殖活动的调控作用与机理及其应用的研究进展进行了综述。  相似文献   

6.
Evolution of mechanisms controlling mating behavior   总被引:4,自引:0,他引:4  
The proximate mechanisms underlying mating behavior in naturally occurring species can be fundamentally different from those in more commonly studied laboratory and domesticated forms. In naturally occurring species, reproductive strategies are much more diverse, and mechanisms controlling behavior are correspondingly diverse. A variety of hormonal, environmental, and social cues can be used to activate mating behavior. Which cues are used by particular species depends on differences in environmental and physiological constraints imposed by particular reproductive strategies. Study of this diversity of mechanisms promises to identify specific selective forces that have shaped their evolution. This evolutionary perspective leads to widely applicable generalizations and provides a useful context within which to conceptualize differences between species, populations, and individuals.  相似文献   

7.
Mechanical stimulation was used to mimic normal vaginal stimuli during copulation in the mouse; the number and rate of intromissions were crucial influences on reproductive success. The best combinations for the mechanical induction of pseudopregnancy were comparable to those male behaviors normally seen during mating. The behavior of the male coincides with a species-related vaginal code, increasing chances for reproductive success between cospecifics.  相似文献   

8.
把血-肾关系看成是水和溶质在它们之间的循环流动,据此对各成分建立物质守恒方程。如果再假设神经一激素调节已足以使 Na~+浓度稳定在标准值附近,则可由此方程式组把肾滤液流(GFR)、血液 pH 值和其他各溶质的浓度都定解为 Na~+浓度和各回收流动力学参数的函数。由定态解可导出以下与传统理论不同的结论:①肾滤液流是被 Na~+回收流按等渗关系决定的,不可能是被血流动力学因素独立决定的。②肾小管钠泵的生理功能是驱动 Na~+-水循环流而不是建立钠浓度。③血液 pH 值是由诸共轭酸离解速度之和为零这一 H~+守恒方程决定的,与缓冲容量无关。④各成分的排泄流都只决定于其摄入流,与肾的调控功能无关等等。  相似文献   

9.
Peptide processing and targeting in the neuronal secretory pathway   总被引:14,自引:0,他引:14  
The abdominal ganglion of the marine mollusk Aplysia contains a pair of identified neuronal clusters, the bag cells, which control egg laying by means of a number of unique regulatory mechanisms. Each neuron in the bag cell clusters synthesizes several peptides derived from a single prohormone and packages them into separate vesicles. These vesicles are then differentially localized in specific neuronal processes, thus segregating peptides destined for autocrine and hormonal release sites. Therefore in this system, protein trafficking through the secretory pathway organizes multiple peptide neurochemical messengers to efficiently regulate simple behaviors.  相似文献   

10.
Organization of endogenous opiate and nonopiate pain control systems   总被引:8,自引:0,他引:8  
  相似文献   

11.
Most rhythmic behaviors such as respiration, locomotion, and feeding are under the control of networks of neurons in the central nervous system known as central pattern generators (CPGs). The respiratory rhythm of the pond snail Lymnaea stagnalis is a relatively simple, CPG-based behavior for which the underlying neural elements have been identified. A three-neuron network capable of generating the respiratory rhythm of this air-breathing mollusk has been reconstructed in culture. The intrinsic and network properties of this neural ensemble have been studied, and the mechanism of postinhibitory rebound excitation was found to be important for the rhythm generation. This in vitro model system enables a better understanding of the neural basis of rhythm generation.  相似文献   

12.
蚜虫行为包括取食行为、繁殖行为、防御行为、社群行为等,本文概述了蚜虫取食行为、排蜜行为、繁殖行为。指出通过对蚜虫取食、排蜜、繁殖行为的研究可以更好地了解其行为发生机制和方式等,为蚜虫的综合治理提供理论基础。  相似文献   

13.
Traditional studies of electrophysiological correlates of behavior contain inherent high variability resulting from the arbitrary choice of behaviors, brain locations, and wave parameters. The operant control of neural events is a formal and systematic approach to the study of prespecified parameters and components of brain activity as they encode behaviors. Two studies in which the electrical activity of brain was the criterion for reinforcement demonstrate the acquisition, under such operant control, of two mutually exclusive behaviors or states which selectively alter evoked potential components.  相似文献   

14.
Experience with the use of progestinestrogen preparations as oral contraceptives indicates that they inhibit fertility by preventing ovulation and that their action is clearly a physiological process. Their efficiency as antifertility agents is extraordinary. An examination of their physiological effects over many years of use indicates that actions to be expected from the hormonal properties of the steroidal components occur but that none of these constitute pathological phenomena. Rather, we observe a state conditioned by the rather constant hormonal milieu resulting from the particular dosages and regimes of use. Thus far, despite use by millions of women, none of the alleged pathological adverse reactions (such as thromboembolism) to the drugs have been established as more than coincidental. Clearly beneficial effects are inherent not only in the avoidance of risks attendant upon pregnancy but also in improvements in menstrual function (regularity, reduction of hypermenorrhea and dysmenorrhea) and perhaps in a prophylactic effect upon certain abnormalities of the reproductive tract (cervical anaplasia, endometrial cystic and adenomatous hyperplasia). Psychogenic phenomena due to use of oral contraceptives are difficult to measure, but beneficial effects would seem to outweigh adverse ones.  相似文献   

15.
Young animals engage in variable exploratory behaviors essential for the development of neural circuitry and adult motor control, yet the neural basis of these behaviors is largely unknown. Juvenile songbirds produce subsong-a succession of primitive vocalizations akin to human babbling. We found that subsong production in zebra finches does not require HVC (high vocal center), a key premotor area for singing in adult birds, but does require LMAN (lateral magnocellular nucleus of the nidopallium), a forebrain nucleus involved in learning but not in adult singing. During babbling, neurons in LMAN exhibited premotor correlations to vocal output on a fast time scale. Thus, juvenile singing is driven by a circuit distinct from that which produces the adult behavior-a separation possibly general to other developing motor systems.  相似文献   

16.
研究一类具双阈值常数时滞二元神经网络模型,系统分析了不同阈值情形解的渐近行为.特别对临界阈值情形,建立了一些新的充要条件.  相似文献   

17.
研究了具有两类靶细胞和CTL免疫应答与抗体免疫反应的时滞病毒感染模型的动力学行为.模型描述了病毒和两类细胞的相互作用:CD4+T淋巴细胞与巨噬细胞.通过构造适当的Lyapunov泛函,使用LaSalle不变性原理,证明了CD4+T淋巴细胞和巨噬细胞的基本再生总数R0、CTL免疫再生数R1、抗体免疫再生数R2、CTL免疫竞争再生数R3和抗体免疫竞争再生数R4决定了模型的全局性态.若R0≤1,病毒在体内清除.若R0〉1,正解在R1≤1,R2≤1时趋于无免疫平衡点,在R1〉1≥R4时趋于CTL主导平衡点,在R2〉1≥R3时趋于抗体主导平衡点,在R3〉1且R4〉1时趋于正平衡点,获得了无病平衡点、无免疫平衡点、CTL主导平衡点、抗体主导平衡点和正平衡点全局渐近稳定的充分条件.  相似文献   

18.
The memory consolidation hypothesis proposed 100 years ago by Müller and Pilzecker continues to guide memory research. The hypothesis that new memories consolidate slowly over time has stimulated studies revealing the hormonal and neural influences regulating memory consolidation, as well as molecular and cellular mechanisms. This review examines the progress made over the century in understanding the time-dependent processes that create our lasting memories.  相似文献   

19.
Monosodium glutamate was injected subcutaneously in infant rats of both sexes. The lateral preoptic and arcuate nuclei and median eminence were examined by light and electron microscopy for possible monosodium glutamate effects. As adults, treated animals showed no adverse monosodium glutamate effects on the reproductive system and neural morphology.  相似文献   

20.
天津白母猪生殖器官发育和生殖激素变化规律   总被引:1,自引:0,他引:1  
试验选用不同年龄天津白母猪 32头,测定了其性发育过程中生殖器官发育和血清生殖激素含量变化规律。结果表明:天津白母猪初情期前发育过程可以划分为 0~ 2月龄、2~ 5月龄和静止期三个阶段。0~ 2月龄母猪卵巢和输卵管生长缓慢,卵巢上只有腔前卵泡,但子宫发育较快;出生后血清LH和E2 浓度迅速下降并保持较低水平,FSH相对稳定。2~ 5月龄段所有生殖器官都快速生长,尤以卵巢最为突出;3月龄血清LH、FSH和E2浓度均出现一个上升波,同时有腔卵泡开始突出至卵巢表面。在静止期,卵巢和输卵管发育明显减慢,而子宫则仍然较快发育;血清中三种激素浓度保持较低水平。6月龄时三种激素浓度再次上升,6 75月龄时P4 浓度显著升高且个体差异很大。据此综合推断出天津白母猪大致在 190 2 0 0d之间达到初情期  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号