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1.
The lower Mississippi River(LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that includes recreational and commercial fisheries. Due to river training and diversion structures constructed during the past 80 years, the historic characteristics of the LMR have been drastically altered and have likely influenced fishes and fisheries in the system. One common restoration measure used throughout the LMR has been to "notch" wing-dike structures that close secondary(side) river channels. Dike notching allows year-round flows through secondary channels, which enhances habitat diversity and promotes biological productivity at the ecosystem scale. Although notching is presumed good for LMR fishes and other biota, few studies have examined its effects on fish assemblages. In this study, fish assemblages were sampled at seven LMR secondary channels spanning from river kilometer(rkm) 628(Louisiana-Mississippi, U.S.A.) upstream to rkm 1504(Missouri-Kentucky, U.S.A.). Four secondary channels were termed "permanent"(i.e.,with notched dikes) while three secondary channels were termed "temporary"(i.e., without notched dikes).Fishes were sampled by boat-mounted electrofishing conducted during falling and low stages from1995—1997. Fish assemblages differed between permanent and temporary secondary channels, and varied somewhat between falling and low stages. Gizzard shad(Dorosoma cepedianum), threadfin shad(D. petenense), and white bass(Morone chrysops) demonstrated consistent preferences for low-current conditions associated with temporary secondary channels. Conversely, blue catfish(Ictalurus furcatus), flathead catfish(Pylodictis olivaris), and freshwater drum(Aplodinotus grunniens) were more associated with permanent secondary channels. Future restoration strategies in the LMR should consider dike notching and resultant maintenance of permanent secondary channels in selected river reaches. However, temporary secondary channels also contain unique fish species, and also appear to be important sites of riverine primary production. Restoration strategies should consider a balance of both secondary channel types, which should support the greatest biodiversity for the LMR ecosystem.  相似文献   

2.
神锢的松动     
郭建崴 《化石》2016,(3):59-60
正如前所述,欧洲历史上的中世纪是个"黑暗时代"。作为当时封建社会的精神支柱,基督教教会把上帝当做绝对的权威,建立了一套严格的等级制度。人的一切思想和行为都必须依《圣经》而为,否则就要受到教会的制裁,甚至被教会设立的宗教审判所处以各种残酷的死刑。在教会的管制下,中世纪的文学艺术死气沉沉,科学技术也没有多少进展。11世纪以后的欧洲,随着经济的复苏与发展、城市的兴起以及生活水平的提高,人们逐渐  相似文献   

3.
丙泊酚应用于无痛人工流产800例分析   总被引:1,自引:0,他引:1  
目的:探讨丙泊酚在无痛人工流产术中的应用效果.方法:将886例早孕未产妇女和/或有剖宫产史妊娠妇女分为试验组和对照组,试验组800例,对照组86例.不采取镇痛麻醉的86例为对照组,试验组对人工流产病人施行丙泊酚静脉全身麻醉,并静脉给阿托品,其余操作同对照组.观察比较两组术中反应、手术时间、出血量与人工流产综合征的发生情况.结果:试验组病人无痛苦,舒适满意,手术时间明显缩短,无一例发生人工流产综合征.对照组69例(80.2%)诉疼痛难忍,11例(12.8)诉下腹痛但可以忍受,6例患者(7.0%)完全不痛.结论:丙泊酚具有高效,显效快速和安全的特点,静脉给丙泊酚可防止人工流产综合征的发生.  相似文献   

4.
激光处理植物种子产生的效应概述   总被引:2,自引:0,他引:2  
大量研究表明,激光处理植物种子,会对植物种子性能及其萌发的植物体产生各种各样的影响.光对植物体的生长发育起着重要的作用,各种植物体在自然光的环境中形成了稳定的生理形态,在短时间内种子及其以后萌发的植物体不会有生理形态上的明显变化.激光不是自然光,用激光处理植物种子会对植物种子性能及其萌发的植物体产生各种各样的影响.本文论述了激光处理对种子及其以后萌发的植物体产生的效应影响进展.  相似文献   

5.
付义强  刘忠 《四川动物》2008,27(2):244-244
2008年1月17日下午4时左右,笔者在四川乐山市水口镇大渡河边发现1只家燕正在河面低空飞行捕食.2008年1月25日西华师范大学杨志松博士在该市岷江边天池村及金灯村一带先后发现5小群家燕,分别为4只、1只、10只、1只和3只;同日,胡杰博士在该市青衣江边(金水湾至乐山高新区江段)也发现2小群家燕,分别为4只和6只.  相似文献   

6.
双翅目昆虫果蝇、摇蚊已成为观察染色体实验的经典材料,结合作者实践中的体会,谈几点做好本实验应注意的问题,重点是:幼虫要看颜色,唾腺要看形态及透明度,染色要把握好时间,压片要经过冷激等.  相似文献   

7.
Insulin resistance(IR)is associated with several metabolic disorders,including type 2 diabetes(T2D).The development of IR in insulin target tissues involves genetic and acquired factors.Persons at genetic risk for T2D tend to develop IR several years before glucose intolerance.Several rodent models for both IR and T2D are being used to study the disease pathogenesis;however,these models cannot recapitulate all the aspects of this complex disorder as seen in each individual.Human pluripotent stem cells(hPSCs)can overcome the hurdles faced with the classical mouse models for studying IR.Human induced pluripotent stem cells(hiPSCs)can be generated from the somatic cells of the patients without the need to destroy a human embryo.Therefore,patient-specific hiPSCs can generate cells genetically identical to IR individuals,which can help in distinguishing between genetic and acquired defects in insulin sensitivity.Combining the technologies of genome editing and hiPSCs may provide important information about the genetic factors underlying the development of different forms of IR.Further studies are required to fill the gaps in understanding the pathogenesis of IR and diabetes.In this review,we summarize the factors involved in the development of IR in the insulin-target tissues leading to diabetes.Also,we highlight the use of hPSCs to understand the mechanisms underlying the development of IR.  相似文献   

8.
横断山区是中国柴胡属Bupleurum植物的分布中心。本文对横断山区6个种2变种进行了染色体记数报道,其中4个种2变种是首次报道。对横断山区的10个种4个变种、中国北方(河北和黑龙江)的3个种的nrDNA ITS进行测序,同时从GenBank里面下载同属的来自非洲和地中海西部的16个nrDNA ITS序列数据,结合染色体数目变化结果,初步探讨了横断山区柴胡属植物的系统发育。结果表明横断山区可能是现代柴胡属植物的频度中心和多样分布中心之一。它们的祖先种可能是非洲北部的木本柴胡属植物B.fruticosum,或者是地中海西部的柴胡属植物,推测是通过中东和高加索扩散而形成的,其中与非洲南部特有种B.mundtii的亲缘关系也较近;染色体基数演化趋势是:8是较原始基数,6和7是次生基数,其染色体异基数变异和多倍化可能是物种形成、进化以及向外扩散的主要方式;在ITS系统发育树中,中国柴胡属植物染色体基数为8的种类聚为一支,染色体基数为6和7的种类聚为了一支,不支持舒璞等(1998)关于中国柴胡属的属下分类系统。结合已有的形态学、细胞学、孢粉学证据和ITS系统发育树,建议窄竹叶柴胡B.marginatum var.stenophyllum独立成种。  相似文献   

9.
从水麻(Debregeasia orientalis C J Chen)地上部分的95%乙醇提取物中首次分离到18个化合物,应用波谱方法或与已知品对照的手段鉴定它们为棕榈酸 (1)、正二十烷酸 (2)、正二十烷酸甲酯 (3)、β-谷甾醇 (4)、Monogynol A (5)、白桦酸 (6)、Hederagenin (7)、β-胡萝卜甙 (8)、18αH-20(29)-烯-3-酮-乌苏烷 (9)、3,4-开环-20(29)-烯-乌苏烷-3-酸 (10)、Pomolic acid (11)、表儿茶素 (12)、儿茶素 (13)、槲皮素 (14)、槲皮素-3-O-β-D-吡喃葡萄糖苷 (15)、紫丁香苷 (16)、紫丁香酚苷 (17)和山萘酚-3-O-β-D-芦丁糖苷 (18).  相似文献   

10.
为了在Epstein-Barr病毒(EBV)172kb的基因组中引入突变以研究基因功能,建立了一种简单有效的基因操作方法.在载体pcDNA3.1( )上操作,将两端含有重组蛋白FLP识别位点(FRT)的卡那霉素筛选标记基因(kan)与鼻咽癌(NPC)来源的、包含LMP1基因全长ORF的gDNA"无缝"连接(无外源序列插入).连接后的kan-LMP1线性DNA片段经转化、由λ噬菌体中redαβγ系统介导在E.coli中发生同源重组(ET克隆),用kan-LMP1替代了BAC-EBV(p2089)中相应的LMP1基因区域,然后经过重组蛋白FLP对FRT-kan-FRT特异性的识别,切除了引入的kan基因,留下一个69bp的FRT"疤痕".通过抗性筛选和对菌液进行PCR扩增可以鉴定突变子.这种经改进并程序化的方法.也适应于引入其它突变或在其它BAC-疱疹病毒基因组中引入突变.  相似文献   

11.
对中国广西的齿甲属Uloma Dejean进行了分类整理,给出已知种检索表,描述4新种和1中国新纪录种,模式标本除特别注明保存地外,其余均保存于河北大学博物馆.  相似文献   

12.
记述中国福建武夷山齿甲属Uloma Dejean 3新种和1新纪录种,模式标本保存于河北大学博物馆.  相似文献   

13.
记述了中国齿甲属UlomaDejean2新种,即扁平齿甲U.compressa sp.nov.和方胸齿甲U.quadratithoraca sp.nov.。模式标本保存在河北大学博物馆。1 扁平齿甲,新种Uloma compressa sp.nov.(图1 ~8 , 17)新种与眼脊齿甲U.nanshanchica Masumoto et Nisiiikawa,1986相似,主要区别:眼内侧无横脊;触角较长,达到前胸背板基部1/2处;前胸腹板中间有少许短毛;鞘翅行间扁平;后足第1跗节明显长于末节。正模♂,云南景东景屏利月(1 630m) , 2001-11-16 ,童正强采。副模1 ♂,张家界, 1986-07 ,采集者不详。词源:种名由拉丁词compressus(扁压的,直的)变化词尾而来,意指该虫身体扁平。2 方胸齿甲,新种Uloma quadratithoraca sp.nov.(图9 ~16 , 18)新种与贡山齿甲U.gongshanicaRenetLiu, 2004相似,主要区别:体中等大小,红棕色;触角末节很长,卵形,端部尖;下颚须末节细长,近刀状;前胸背板方形;前胸腹板突末端缓慢下降。正模♂,湖南省溆浦县大江口, 1962-04 ,邓爱国采。词源:种名由拉丁语词quadratus(成方形的) 拉丁语词thorac(胸部)组合并变化词尾而成,意指该虫的前胸背板为方形。  相似文献   

14.
New Caledonia is an important biodiversity hotspot with much undocumented biodiversity, especially in many insect groups. Here we used an integrative approach to explore species diversity in the tenebrionid genus Uloma (Coleoptera, Tenebrionidae, Ulomini), which encompasses about 150 species, of which 22 are known from New Caledonia. To do so, we focused on a morphologically homogeneous group by comparing museum specimens with material collected during several recent field trips. We also conducted molecular phylogenetic analyses based on a concatenated matrix of four mitochondrial and three nuclear genes for 46 specimens. The morphological study allowed us to discover and describe four new species that belong to the group of interest, the Uloma isoceroides group. Molecular analyses confirmed the species boundaries of several of the previously described species and established the validity of the four new species. The phylogenetic analyses also provided additional information on the evolutionary history of the group, highlighting that a species that was thought to be unrelated to the group was in fact a member of the same evolutionary lineage. Molecular species delimitation confirmed the status of the sampled species of the group and also suggested some hidden (cryptic) biodiversity for at least two species of the group. Altogether this integrative taxonomic approach has allowed us to better define the boundaries of the Uloma isoceroides species group, which comprises at least 10 species: Uloma isoceroides (Fauvel, 1904), Uloma opacipennis (Fauvel, 1904), Uloma caledonica Kaszab, 1982, Uloma paniei Kaszab, 1982, Uloma monteithi Kaszab, 1986, Uloma robusta Kaszab, 1986, Uloma clamensae sp. n., Uloma condaminei sp. n., Uloma jourdani sp. n., and Uloma kergoati sp. n. We advocate more studies on other New Caledonian groups, as we expect that much undocumented biodiversity can be unveiled through the use of similar approaches.  相似文献   

15.
魏江春  姜玉梅 《菌物学报》1992,11(Z1):73-88
本文报导了石耳科的八个种,其中新种四个,即阿尔泰石耳,鳞芽石耳、亚石耳及太白石耳;三个种是中国的新分布,即皱石耳、亚光石耳及淡腹疤脐衣;一个种即白根石耳为中国及蒙古的新分布。  相似文献   

16.
The Solikamsk faunas of the Vorkuta series of the Pechora Basin and the Solikamsk Formation of the Perm Region of Russia are reviewed. New taxa are described from Tyul’kino locality (Solikamsk District): Artinska ufimica sp. nov., Sylvaprisca tyulkinensis sp. nov., Ufimoprisca gen. nov. (the type species Sylvaprisca alba Aristov, 2005), U. mica sp. nov., U. kamensis sp. nov. (family Lemmatophoridae), Sylvaella ovalis sp. nov. (family Liomopteridae), Ivakhosara prima sp. nov., and Megakhosarella prisca sp. nov. (family Megakhosaridae). Additionally, Uralioma sp. is described from Shchugor locality (Cherdyn’ District). Two species, Paraprisca solikamskensis Aristov, 2009 (family Lemmatophoridae) from Tyul’kino and Kolvidelia curta G. Zalessky, 1950 (family Ideliidae) from Pokcha locality (Cherdyn’ District)), are redescribed.  相似文献   

17.
An exceptionally well-preserved collection of Tertiary opisthobranch molluscs from the Aquitaine Basin, France, includes species of the order Notaspidea [ Umbraculum sanctipaulensis sp. nov., Tylodina perversa (Gmelin), Spiricella unguiculus Rang and Des Moulins, Berthella aquitaniensis sp. nov., Berthella ateles sp. nov.], of the order Anaspidea [ Akera cf. bullata Mu¨ller, Floribella corrugata (Cossmann), Floribella cossmanni sp. nov., Floribella rozieri sp. nov., Limondinia ornata gen. et sp. nov.] and of the order Sacoglossa [ Volvatella faviae sp. nov.]. Berthella aquitaniensis B. ateles V. faviae are the first fossil records of the families Volvatellidae and Pleurobranchidae. Floribella plicifera (Cossmann) and F. corrugata , originally assigned to the genus Philine , belong to the genus Floribella and constitute the oldest records of this genus. The fossil evidence indicates that in Umbraculum laudunensis and U. sanctipaulensis the shell probably covered most of the animal, whereas in the Recent U. umbraculum the shell only covers the central portion of the body. Tylodina perversa could be an old species that appeared during the early Miocene, more than 21 Ma. The Recent shells of Akera bullata are indistinguishable from fossils as old as the mid Eocene, but it may be biologically unrealistic to consider them to be the same species. The European species of Floribella evolved from the bullomorph shells of the early Eocene forms to the elongate shells of the early Miocene. The genus Volvatella is another example of marine tropical disjoint distributions and an excellent ecological indicator.  相似文献   

18.
报道了中国列蛾属Autosticha 33种昆虫,其中有23新种和中国3新纪录种.新种包括:连斑列蛾A.conjugiopuncla sp.nov.,茨坪列蛾A.cipingensis sp.nov.,小喜列蛾A.microphilodema sp.nov.,多斑列蛾A.maculosa sp.nov.,勐仑列蛾A.menglunica sp.nov.,粗鳞列蛾A.squarrosa sp.nov.,南昌列蛾A.nanchangensis sp.nov.,淡黄列蛾A.flavida sp.nov.,二瓣列蛾A.valvifida sp.nov.,复瓣列蛾A.complexivalvula sp.nov.,迷列蛾A.fallaciosa sp.nov.,直斑列蛾A.rectipunctata sp.nov.,齿瓣列蛾A.valvidentata sp.nov.,天目山列蛾A.tianmushana sp.nov.,异域列蛾A.heteramalla sp.nov.,沈氏列蛾A.shenaesp.nov,五峰列蛾A.wufengensis sp.nov.,奇异列蛾A.mirabilis sp.nov.,弓瓣列蛾A.arcivalvaris sp.nov.,刺列蛾A.oxyacantha sp.nov.,棒列蛾A.bacilliformis.sp.nov.,赤水列蛾A.chishuiensis sp. nov.和涉县列蛾A.shexianicasp.nov..中国新纪录种有:和列蛾A.modicella(Christoph,1882),粗点列蛾A.pachysticta(Meyrick,1936)和截列蛾A.truncicola Ueda,1997.此外,还报道了1个新组合--喜列蛾A.philodema(Meyrick,1938),comb.nov..文中提供了新种的外生殖器特征图.模式标本保存在南开大学生物系.  相似文献   

19.
报道了中国隐织蛾属CryptolechiaZeller三十三种昆虫 ,包括十五新种 :湾隐织蛾C .deflectasp .nov .,康县隐织蛾C .kangxianensissp .nov .,小袋隐织蛾C .microbyrsasp .nov .,伪黄昏隐织蛾C .falsivespertinasp .nov .,郑氏隐织蛾C .zhengisp .nov .,新白芯隐织蛾C .neargometrasp .nov .,拟花茎隐织蛾C .paranthaedeagasp .nov .,角瓣隐织蛾C .cornutivalvatasp .nov .,断带隐织蛾C .fasciruptasp .nov .,点带隐织蛾C .stictifasciasp .nov .,鸡公山隐织蛾C .jigongshanicasp .nov .,奇异隐织蛾C .mirabilissp .nov .,花茎隐织蛾C .anthaedeagasp .nov .,葛氏隐织蛾C .geisp .nov .以及伪断带隐织蛾C .varifasciruptasp .nov .。文中提供了新种的外生殖器特征图。模式标本保存在南开大学生物系。  相似文献   

20.
Twenty-four new spider species of the family Dictynidae from caves of Guangxi and Guizhou in southern China are described,accompanied by line drawings and photomicroscopy images.Fifteen of them belong to Brommella Tullgren,1948:B.baiseensis Li,sp.nov.,B.casseabri Li,sp.nov.,B.chongzuoensis Li,sp.nov.,B.dolabrata Li,sp.nov.,B.funaria Li,sp.nov.,B.josephkohi Li,sp.nov.,B.linyuchengi Li,sp.nov.,B.renguodongi Li,sp.nov.,B.resima Li,sp.nov.,B.sejuncta Li,sp.nov.,B.spirula Li,sp.nov.,B.tongyanfengi Li,sp.nov.,B.wangfengcheni Li,sp.nov.,B.xinganensis Li,sp.nov.and B.yizhouensis Li,sp.nov.;eight to Cicurina Menge,1871:C.avicularia Li,sp.nov.,C.damaoensis Li,sp.nov.,C.dong Li,sp.nov.,C.kailiensis Li,sp.nov.,C.majiangensis Li,sp.nov.,C.parallela Li,sp.nov.,C.wusanani Li,sp.nov.,and C.zhazuweii Li,sp.nov.;one to Lathys Simon,1884:L.inaffecta Li,sp.nov.Types of all new species are deposited in the Institute of Zoology,Chinese Academy of Sciences in Beijing (IZCAS).  相似文献   

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