A Quantitative Assessment of the Reproductive System of the Mediterranean Cave-Dwelling Triplefin Blenny Tripterygion melanurus

Abstract. The breeding biology of the cave-dwelling Mediterranean triplefin blenny Tripterygion melanurus (Pisces, Blennioidei) was studied in the field. Two types of reproductive male were observed, territorial males and non-territorial males. Territorial males establish territories for mating, but not necessarily for feeding, in caves and crevices at depths between 0.5 and 33  m. Territories can be settled in clusters in a single cave. Non-territorial males occur in the vicinity of territories and attempt to parasitise matings of territorial males. Gravid females wait near territories where another female is spawning, rather than spawn with currently unmated territorial males. Waiting females intrude in matings and sometimes displace a spawning female. The frequency of mating of the territorial male, of sneaking and of female intrusions are higher in territories that border others than in isolated territories. Females may minimise predation risks both on themselves and on their eggs by spawning in clustered territories and by spawning with males that have more than one clutch of eggs. Territorial males must find a compromise between the benefits of attracting a female and the costs of parasitic spawning by sneaker males. The possibility that territorial males tolerate the proximity of other territorial males and accept a risk of cuckoldry is discussed. Parasitic spawning in T. melanurus is relatively rare and the gonadosomatic index in both non-territorial and territorial males is low, indicating that sperm competition is probably not intense.     

Gender,class, and paradoxical mobilities of Thai marriage migrants in Austria

In this paper, we investigate whether marriage‐related migration promotes socioeconomic mobility and how class belonging and educational background affects Thai women's migration experience and socioeconomic mobility. Drawing on qualitative interviews, supported by a questionnaire survey with Thai women living in Austria and who are in a relationship with a Western male citizen, we seek to dismantle simplistic notions about hypergamy and question common assumption about marrying up or down in migration contexts. We compare socioeconomic indicators such as formal education, occupation, and income before and after the migration and analyse migrants’ experiences in Austria. The results show a complex picture of upward and downward socioeconomic mobilities. Two distinct scenarios of paradoxical mobilities have been identified. On the one hand, some migrants feel empowered (when experiencing economic downward mobility) as they enjoy the freedom of living in Austria, while on the other hand, those migrants experiencing upward mobility feel a loss of their personal autonomy.     

三倍体虹鳟(Oncorhynchus mykiss)卵巢分化及滞育的调控机制研究

尽管与性别决定和分化的相关基因在二倍体虹鳟中已被鉴定出来,如Cyp19a1a、Foxl2、Dmrt1、Amh和Sox9,但关于三倍体雌性虹鳟独特性腺表型及其相关性别控制基因的表达规律仍未得到深入研究,尤其是早期卵巢发育阻滞导致的生殖细胞去分化特征。因此,本研究以三倍体雌性虹鳟性腺发育中起重要调控作用的特异候选基因作为重点研究对象,辅助性腺体细胞与生殖细胞分化方向的组织学证据和类固醇激素表达规律,验证了各基因间的级联调控关系。结果表明,虹鳟三倍体与二倍体卵巢的分化特征基本一致。虹鳟二倍体与三倍体性腺分别在84dpf和98dpf就已分化为卵巢。但三倍体虹鳟卵巢分化存在障碍,早期发育停滞,卵原细胞及其滤泡细胞数量有限。Foxl2和Cyp19a1a在二倍体虹鳟卵巢和精巢中均有表达,它们在卵巢中表达量均呈逐渐升高趋势,但在精巢中的表达量非常低;这两个基因在雌性三倍体虹鳟性腺中的表达呈先升高后降低的趋势,其表达量均在8月龄时期达到最大。Dmrt1、Amh和Sox9在二倍体精巢和雌性三倍体卵巢中的表达均呈不断上调趋势,这些基因上调可能与血清睾酮含量的增加相关,因为在10月龄时期这两种鱼的血清含量相对较高,而这三个基因在二倍体虹鳟卵巢中的表达却呈下调趋势。因此本研究认为,维持鱼类卵巢分化需要持续高水平的雌激素,这可能是脊椎动物进化过程中的一个保守特征。可以推断雌性三倍体虹鳟卵巢滞育将导致其体细胞去分化,这对于Cyp19a1a表达及雌二醇合成存在抑制作用。因为这些雌激素是用来维持它们分化和继续发育的,可能产生一个负反馈圈,之后去分化会增强。     

BOOK REVIEWS

Book Reviewed in this article: Redundant Spaces in Cities and Regions? Studies in Industrial Decline and Social Change . J. Anderson, S. Duncan and R. Hudson. eds. The Social Consequences and Challenges of New Agricultural Technologies . Gigi M. Berardi and Charles C. Geisler, eds. Determinants of Fertility in Developing Countries, Vol. I, Supply and Demand for Children . Rodolfo A. Bultao and Ronald D. Lee, eds. Computer Mapping: Progress in the‘80s . James R. Carter. Washington: Colonial Africa . A. J. Christopher. Geography of the Soviet Union . J. P. Cole. Chicago Mapmakers, Essays on the Rise of the City's Map Trade . Michael P. Conzen, ed. Changes in the Land: Indians, Colonists and the Ecology of New England . William Cronon. Mizner's Florida: American Resort Architecture . Donald W. Curl. Geographical Studies on the Soviet Union: Essays in Honor of Chauncy D. Harris . George Demko and Roland J. Fuchs, eds. Fluvial Hydrology . S. Lawrence Dingman. Pueblo Indian Water Rights: Struggle For a Precious Resource . Charles T. DuMars, Marilyn O'Leary and Albert E. Utton. Women in the Cities of Asia: Migration and Urban Adaptation . James T. Fawcett, Siew-Ean Khoo, and Peter C. Smith, eds. America's National Parks and Their Keepers . Ronald A. Foresta. Neighborhood Revitalization and the Postindustrial City . Dennis E. Gale. China in Canada: A Dialogue on Resources and Development . R. Louis Gentilcore, ed. China: The 80s Era . Norton Ginsburg and Bernard A. Lalor, eds. Boulder, CO: Global Resources: Challenges of Interdependence . Martin I. Glassner, ed. River Networks . Texas: A Geography . Terry G. Jordan with John L. Bean, Jr. and William M. Holmes. The American Frontier: An Archaeological Study of Settlement Pattern and Process . Kenneth E. Lewis. Water Resources, Geography and Law . Olen Paul Matthews. A Field Guide to American Houses . Virginia and Lee McAlester. Population: Patterns, Dynamics, and Prospects . James L. Newman and Gordon E. Matzke. Wood, Brick, and Stone, The North American Settlement Landscape, Vol. 1: Houses . Allen G. Noble. Historical Analysis in Geography . William Norton. The Displaced Worker and Community Response: Case Study of Portsmouth, Scioto County, Ohio . H. Milton Patton and Janet W. Patton. Disaster Management: Warning Response and Community Relocation . Ronald W. Perry and Alvin H. Muskatel. The Anthropology of Space: Explorations into the Natural Philosophy and Semantics of the Navajo . Rik Pinxten, Ingrid van Dooren, and Frank Harvey. What STYLE Is It? A Guide To American Architecture . John C. Poppeliers, S. Allen Chambers, Jr., and Nancy B. Schwartz. Appalachia: A Regional Geography—Land, People and Development . Karl Raitz and Richard Ulack. An Introduction to Urban Geography . John R. Short. Ford, A Village in the West Highlands of Scotland: A Case Study of Repopulation and Social Change in a Small Community . John B. Stephenson. Income and Jobs: USA Diagnosing the Reality . George Sternlieb and James W. Hughes. Weather and Climate of the Antarctic . W. Schwerdtfeger. History and Ecology: Studies of the Grassland, James C. Malin . Robert P. Swierenga, ed. Optimal Control of Spatial Systems . K. C. Tan and R. J. Bennett. Social Science and Revolutions . Stan Taylor. The Global Textile Industry . Brian Toyne, Jeffrey S. Arpan, David A. Ricks, Terence A. Shimp and Andy Barnett. Integrated Water Development: Water Use and Conservation Practice in Western Colorado . James L. Wescoat, Jr. Proceedings of the First International Symposium on Maps and Graphics for the Visually Handicapped . Joseph W. Wiedel, ed.     

Gender, immigration policies and accreditation: valuing the skills of professional women migrants

Human capital is the most important form of wealth for a modern nation and countries with the most intellectual resources are achieving the highest rates of economic growth. In the drive for human capital, many industrialised countries are giving priority to policies aimed at attracting highly skilled immigrants. The number of skilled immigrants who settle permanently in these countries is not rising but there is a significant level of temporary movement of highly skilled labour from developing countries, particularly in information technology (IT), medicine, nursing and teaching. Women now account for an increased proportion of highly skilled migrants but there are still few analyses of their economic participation. Immigration selection and occupational entry policies are crucial for an understanding of the gendered experiences of migration for skilled migrants. This article draws together material from empirical work and reports/other literature on the situation facing professional women compared to men, both permanent and temporary, in the selection processes for migration and the post-arrival processes of accreditation and recognition.     

半滑舌鳎(Cynoglossus semilaevis)Patched 1基因的克隆和表达分析

Hedgehog(Hh)信号通路在脊椎动物和非脊椎动物发育过程中细胞信号传导方面发挥重要的作用。Patched 1 (Ptc1)基因是Hh的受体,通过和Hh配体结合调节Hh信号通路。本研究克隆和鉴定了半滑舌鳎的Ptc1基因(csptc1),该基因cDNA全长为5212 nt,编码蛋白包括1543个氨基酸残基,序列比对和进化分析显示该蛋白在进化过程中较为保守。荧光定量显示该基因在脑,肝脏,心脏,鳃,肠,脾脏、肾脏和性腺组织中普遍表达,在精巢中的表达水平显著高于卵巢。精巢中的原位杂交信号主要位于该基因主要在初级精母细胞,次级精母细胞和支持细胞中,而在卵母细胞中的信号较弱。Csptc1基因在卵巢中的甲基化水平高于在雄鱼和伪雄鱼精巢中。这一研究结果可能说明csptc1基因参与了 Desert Hedgehog (DHH)基因维持雄鱼和伪雄鱼的生殖细胞系以及精子发生等生物学过程。     

A method for distinguishing the females and late copepodites of three species of Boeckella

Consistent differences in the morphology of the last metasomal segment and genital segment were found among adult female Boeckella triarticulata, B. dilatata, and B. hamata. These differences are taxonomically useful in collections where males are sparse. Distinguishing features used to classify CIII‐CV B. triarticulata, B. dilatata, and B. hamata of co‐occurring populations to species are also described. The diagnostic features of both adult female and copepodites may be used at low magnifications.     

池塘内循环流水养殖下太湖鲂鲌(翘嘴鲌(♀)×三角鲂(♂))肠道微生物群落变化的研究

为研究池塘内循环流水养殖(In-pond Raceway, IPR)模式下太湖鲂鲌(翘嘴鲌(♀)×三角鲂(♂))肠道微生物群落结构的变化,以传统池塘养殖作为对照组,采用16SrRNA高通量测序方法分析了IPR养殖模式下太湖鲂鲌肠道的菌群结构及环境水体微生物多样性的变化。试验结果表明, IPR模式下太湖鲂鲌肠道微生物群落发生了明显的变化,在门分类水平,梭杆菌门(Fusobacteria)成为绝对优势菌,所占丰度为92.47%;对照组的优势菌由梭杆菌门、变形菌门(Proteobacteria)和厚壁菌门(Firmicutes)组成,三者所占的丰度分别为34.45%、33.30%和21.30%。在养殖水环境中,两种养殖模式的微生物群落数均大于肠道样本,且二者优势菌不同;IPR水环境的优势菌为蓝细菌(Cyanobacteria,36.53%),其次为放线菌门(Actinobacteria,24.67%);对照组水体中的优势菌为放线菌门和变形菌门,分别占细菌总数的38.99%和28.15%。多样性指数结果表明,水环境中的微生物群落Shannon多样性指数、Chao1指数高于肠道样本,IPR养殖对...