多巴胺能药物对鲤鱼生长激素分泌活动的影响

研究多巴胺（Dopamine，DA）及其激动剂阿朴吗啡（Apomorphine，APO）、拮抗剂Domperidone（DOM）对不同性腺发育时期和不同年龄雌鲤生长激素（GH）分泌活动的影响．结果表明，鲤鱼基础GH分泌存在明显的季节性变化：性腺发育早期＜性肠成熟期＜性腺退化期．DA和APO刺激的GH分泌也存在明显的季节性变化：性腺发育早期＞性腺成熟期＞性腺退化期．DOM不影响性腺发有早期和性腺成熟期的GH分泌，但显著性降低性腺退化期的GH水平．6月龄鱼血清基础GH水平明显低于2～3龄和1龄鱼；不同年龄鱼对多巴胺能药物的反应性表现为：1龄色最强，2～3龄和6月龄鱼较弱．     

水温对胡子鲇、革胡子鲇及其杂交子一代胚胎发育的影响

报道了水温对胡子鲇、革胡子鲇及其杂交子一代珠胡子鲇胚胎发育的影响的研究结果．３种胡子鲇胚胎孵化临界水温上限３５℃,下限１８℃;合适温度范围是２０～３４℃,胚胎发育所需时间与水温呈负相关关系,可以用方程式表示：胡子鲇ＴＦ＝４０１７４θ－２１７６５,革胡子鲇ＴＬ＝４１７７６θ－２２７１４,珠胡子鲇ＴＰ＝４１６８３θ－２１９４６．最适孵化温度分别是胡子鲇３０～３４℃,革胡子鲇２６～３２℃和珠胡子鲇２４～３４℃．     

泥鳅的人工繁殖及胚胎发育

在河南省首次对泥鳅进行了大规模人工繁殖试验,并对人工繁殖过程中不同催产剂对催产效果的影响和泥鳅胚胎发育过程作了探讨.试验结果表明,不同催产剂的效应时间和催产效果明显不同.在人工控制条件下,泥鳅性腺发育正常,催产率因催产剂不同而不同,使用LRH-A2和DOM混合催产和使用HCG和LRH-A2混合催产效果更明显,在水温21-24℃、盐度5‰的流水环境中,经25h左右仔鱼大量出膜,体长为3.5-4.8Mm.     

宁波平原地区人工养殖棘胸蛙试验初报

本文对棘胸蛙(Rana spinosa David)在宁波平原地区的人工繁殖和养殖进行了初步的研究,其中包括人工授精和人工孵化;蝌蚪,幼蛙和成蛙的养殖等。对于卵巢发育程度良好的雌蛙,可以100％地催产成功。平均孵化率选74％以上．孵化条件合适时可以达到90％以上。5日龄蝌蚪的成活率选90％以上,80～90d即可变态成幼蛙。幼蛙经过6个月的饲养平均个体重达100g以上,鲜活饵料的料肉比为4．1：1。     

大树蛙早期发育的初步观察

常温条件下，大树蛙早期发育从受精卵到蝌蚪孵化需6d左右，卵群形态、孵化方式等与大多数无尾两栖类有别；胚胎发育、变态发育与其它无尾两栖类相似；在实验室人工饲养下，蝌蚪在孵化后的第29d长出后肢，第36d长出前肢，第43d完成变态发育．     

家庭医生咨询台

山东青岛李读者问：女儿9岁（身高136厘米），胸部已开始发育，不知算不算性早熟或是不是假性性早熟？答：性早熟是指男孩9岁前出现腋毛、阴毛或出现睾丸、阴茎增大；女孩8岁前出现乳房发育，10岁前出现月经。性早熟分真性假性两种。真性性早熟是由于垂体促性腺激素过早兴奋，导致性激素过早分泌所致；假性性早熟是因内分泌腺如性腺、肾上腺等病变引起（常见肿瘤）。根据你说的来看，你女儿情况尚属正常。由于性早熟会影响孩子的最终身高而令父母着急。通过体检、拍摄骨龄片、血液性激素及促性腺激素兴奋试验等检查，医生可对性早熟进行诊断…     

韩江流域大刺鳅人工繁殖技术及染色体核型分析研究

通过对野生大刺鳅进行驯化、培养、人工繁殖研究,探索大刺鳅的人工繁殖方法与技术.同时,通过PHA体内注射低渗法制备大刺鳅的染色体及进行核型分析,了解其染色体数目及形态特征.结果显示,人工催产实验中,雄鱼的产精率为85.7％,雌鱼的产卵率为100％.在不同孵化介质中,以木麻黄针叶为孵化介质的大刺鳅孵化率总体较好,平均孵化率...     

湿度对胭脂虫生长发育影响的探讨

胭脂虫（Dactylopius coccw Costa）具有重要的经济价值，其干体可制备成胭脂红，进一步提取胭脂红色素，广泛地用于食品染料、化妆品、药品等多种行业中。通过研究湿度对D．coccus孵化和生长发育的影响，在50％、70％、90％三种湿度条件下，观察了湿度对D．coccw孵化和种群生长发育的影响。结果表明，不同湿度对D．coccw卵的孵化、若虫及成虫的生长发育都有一定的影响，随湿度的增加，孵化量及孵化率增大，获得的一龄若虫数随湿度的增加而增加，二龄若虫和雌成虫数都是在90％RH时达到最大。说明高湿度对提高卵的孵化及种群生长是有利的。     

妇科专家信箱

Ｑ我现已怀孕７个月，有一件事一直 让我不安，我曾在末次月经的前一个月服过一次紧急避孕药，不知对胎儿是否有影响。目前我所做产前检查均正常。急盼回答。 浙江 江敏Ａ 紧急避孕药是大剂量的人工合成 的孕激素制剂，主要作用于下丘脑和垂体，通过抑制垂体促性腺激素的分泌，使促卵泡激素和促黄体生成激素水平降低或消头，抑制排卯；对子宫内膜亦有较强的抑制作用，影响孕卵着床。用于紧急避孕时，是通过抑制卵泡发育、抑制或延迟排卵、影响子宫内膜发育、干扰着床等不同环节，达到避免妊娠的目的。由于紧急避孕药会使激素水平有所改变，…     

对“高等动物激素”的教学处理

对高等动物的激素（以下简称激素），人教1990年第一版的高中《生物（必修）》第126页作如下叙述：“高等动物与人一样，体内有甲状腺、肾上腺、性腺和垂体等多种内分泌腺。这些内分泌腺分泌的激素，对……具有调节的作用”。人教1991年第一版《生物（选修））第143。144页也作意思完全相同的叙述。如此叙述必然使中学师生产生这样的概念：l、“内分泌系统就是由内分泌腺组成的”（人教1993年第一版《生理卫生》第107页作的叙述）；2、激素只是内分泌腺体的产物，或者说内分泌腺所分泌的物质才是激素。此概念在知识上显有以偏概全之嫌，在教…     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

汉字倒说

汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

钱生钱!

我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了     

Social and Cultural Influence on Word Meaning

Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language.     

Inequalities for inscribed simplexes

The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.