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1.
内蒙古西部荒漠区(包括阿拉善荒漠的绝大部份和中央戈壁荒漠的一部分)是亚非荒漠区——亚洲中部荒漠亚区的一个重要组成部分。这里是亚洲中部戈壁荒漠许多古老特有属、特有种和特有植物群落的集中分布区。阿拉善荒漠的东界还是亚非荒漠和欧亚草原两大植物  相似文献   

2.
3只红腹锦鸡食管和大肠的显微结构观察   总被引:2,自引:2,他引:2  
用组织学方法对 3只红腹锦鸡 (Chroysolophuspictus)食管和大肠进行了显微结构观察 ,结果显示 :红腹锦鸡食管和大肠均由粘膜层、粘膜下层、肌层和外膜 4层结构组成 .食管的粘膜和粘膜下层突入腔内形成几条纵行皱襞 ,上皮为未角化的复层扁平上皮 ,固有膜内有较发达的食管腺 ,粘膜肌为纵行排列的平滑肌 ,粘膜下层相对较薄 ,肌层由内环和外纵行平滑肌组成 .大肠由盲肠和直肠组成 .盲肠的粘膜和粘膜下层形成环状皱襞 ,直肠则无皱襞结构 .从盲肠到直肠 ,绒毛逐渐变得宽短和稀疏 ,未见中央乳糜管 ,肠腺逐渐减小 ,上皮和腺体的细胞之间杯状细胞渐少 ,粘膜下层逐渐不明显 ,淋巴组织由发达到不发达 ,盲肠的粘膜下层的淋巴集结见有生发中心 .将观察结果与其它鸟类进行了比较 .  相似文献   

3.
为了探索纤毛虫休眠细胞中两套遗传系统的作用特征,对包囊游仆虫(Euplotes encysticus)休眠细胞与营养细胞大核DNA和线粒体DNA进行了RAPD比较.结果显示,在所选用的35条随机引物中,包囊游仆虫大核DNA共扩增出220条片段,其中以休眠细胞大核DNA为模板扩增出18条特有片段,以营养细胞大核DNA为模板扩增出44条特有片段,两者存在28%的差异.在所选用的32条随机引物中,线粒体DNA共扩增出154条片段,其中以休眠细胞线粒体DNA为模板扩增出19条特有片段,以营养细胞线粒体DNA为模板扩增出25条特有片段,两者有29%的差异.这些结果表明,包囊游仆虫休眠细胞与营养细胞的大核DNA结构存着一定的差异;两者的线粒体DNA结构也存在差异.因此,包囊游仆虫在休眠细胞形成过程中,大核DNA、线粒体DNA结构可能都发生了一定的变化,并且这些变化可能与休眠细胞形成过程中的形态结构和代谢活动等剧烈变化以及休眠状态下的生理生化变化密切相关.所得结果为揭示纤毛虫细胞结构的分化与细胞遗传物质的作用关系提供了基础资料.  相似文献   

4.
研究了赤腹松鼠消化道各部的形态和组织学结构.结果表明,赤腹松鼠消化道由口、咽、食管、胃、十二指肠、空肠、回肠、盲肠、结肠和直肠等器官组成.除口咽腔外,消化管壁分为黏膜层、黏膜下层、肌层和外膜.各部主要区别在于黏膜层:口腔、咽和食道的黏膜上皮为复层扁平上皮;胃、肠黏膜为单层柱状上皮.食道黏膜肌层较厚,而胃、小肠、盲肠和结肠的黏膜肌层则很薄.管壁皱襞的形态、腺体的分布情况、肌层的相对厚度等在消化道各部也存在差异.此外,未观察到舌表面的味蕾和食道中的食管腺.研究表明赤腹松鼠消化道结构与其食性是相适应的.  相似文献   

5.
本文报道了爪鲵甲状腺的形态学与组织学的结构特点。爪鲵有甲状腺一对,位于颏舌骨肌下部外侧,介于关节下直肌和颈直肌之间,附于第一腮弓的软骨上。腺体呈卵圆形,两端较钝圆,甲状腺为滤泡结构,由甲状腺滤泡组成,滤泡的形状、大小变化很大,常呈圆形、卵圆形和不规则的球形。滤泡细胞为单层立方或柱状上皮细胞,游离面光滑,细胞质染色均匀,细胞核大,滤泡腔中充满滤泡上皮细胞分泌的胶质。在滤泡之间,充有少量疏松结缔组织。  相似文献   

6.
沙蟒皮肤,消化及雌性尿殖器官的组织学研究   总被引:2,自引:0,他引:2  
对沙蟒(Eryx miliaris)的皮肤、消化和雌性尿殖器官进行了组织学研究。皮肤缺少皮肤腺,消化管的共同组织学特征是由粘膜、粘膜下层、肌层和浆膜组成。卵巢为长囊状致密器官,位置不对称,右侧前于左侧,卵巢外层为生殖上皮,内为结缔组织,输卵管壁分为粘膜层、肌层和浆膜层。肾为长形,分5~6叶,右侧输尿管较长。  相似文献   

7.
运用组织学常规方法对蒙古绵羊32~550 mm胚胎小肠的组织学特征以及肌层、粘膜肌、粘膜上皮、杯状细胞、淋巴集结、乳糜管、肠腺、十二指肠腺等发生发育规律进行了较详细的研究.结果:在小肠各段肌层已分化出内环肌和外环肌;十二指肠、空肠、回肠在290 mm胚胎时出现了明显的粘膜肌;粘膜上皮发生发育经历了从单层细胞到多层细胞再到单层细胞的过程;十二指肠、空肠、回肠在各胚期相继出现了杯状细胞、乳糜管、肠腺;回肠在340 mm胚胎、空肠在400 mm胚胎出现了淋巴集结;十二指肠在290 mm胚胎出现了十二指肠腺.  相似文献   

8.
对荒漠沙蜥成体代谢率和心率等生理指标的温度适应性进行了研究,旨在检测不同温度下成体荒漠沙蜥的静止代谢率、心率和呼吸频率的差异.结果显示:成体荒漠沙蜥的静止代谢率和心率随外界温度的升高而明显上升,但呼吸频率的上升并不显著.雌雄两性间,雄性蜥蜴呼吸频率对温度变化的依赖性比雌性的略强,且35?C下雄性的代谢率显著高于雌性的.这些生理特征与荒漠沙蜥的生境和活动特点直接相关.我们推测25~35?C荒漠沙蜥可能更多地依赖于提高心率和增加血流量来调整代谢率.  相似文献   

9.
为搞清灰背隼(Falco columbarius)胃、小肠的组织学结构与功能,用组织切片技术、Grimelius银染法和免疫组织化学方法观察分析了灰背隼胃和小肠的组织学结构、嗜银细胞分布和Gherlin的表达情况.结果表明,灰背隼胃属单胃,胃黏膜表面有大量胃小凹,固有膜中有大量的单管状胃腺,胃肌层可分为内环、中斜、外纵行三层平滑肌.小肠肠壁由黏膜、肌层及外膜组成,黏膜表面有许多指状肠绒毛,绒毛中有中央乳糜管和毛细血管,小肠肌层由内环形和外纵形两层平滑肌组成.嗜银细胞分布于胃和小肠粘膜上皮、固有膜及腺体上皮中,形态多样,分布密度呈递减趋势.Gherlin在胃、小肠中均有表达,表达量呈递减趋势,与器官的消化机能密切相关.  相似文献   

10.
蒙古绵羊胚胎肠绒毛的组织发生   总被引:1,自引:0,他引:1  
用组织学常规方法研究32~550 mm蒙古绵羊胚胎各段肠的组织学结构.研究结果显示,蒙古绵羊各肠段在发育过程中都有绒毛的发生,且绒毛发育呈现了各自不同的特点:肠绒毛发生时期不同,发生过程不同,大肠绒毛退化消失时期也不同.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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