Distribution and characterization of Chilean populations of the brine shrimp Artemia (Crustacea, Branchiopoda, Anostraca)     

Oscar Zuñiga  Rodolfo Wilson  Francisco Amat  Francisco Hontoria 《International Journal of Salt Lake Research》1999,8(1):23-40

Hypersaline habitats in Chile, from marine solar salt pans to saline lagoons and pools in Andean salars, were prospected in search of Artemia populations. These saline ecosystems were characterized through physico-chemical parameters and ionic composition of their brines. Biometrics of cysts and nauplii, as well as morphometrics by using multivariate discriminant analysis for adult specimens evidenced that the Chilean populations of brine shrimp belong to A. franciscana. Cross-breeding results supported the former hypothesis of conspecific Chilean populations, and their differences with A. persimilis, also endemic to the New World, but restricted to Argentinean sites.  相似文献   

European quaternary refugia: a factor in large carnivore extinction?     

Hannah J. O'Regan  Alan Turner  David M. Wilkinson 《第四纪科学杂志》2002,17(8):789-795

The extinction of large carnivores in Europe during the Quaternary is reviewed and the potential role of glacial refugia in these extinctions is investigated using the VORTEX model for population viability analysis. A model was built for a medium sized big cat similar to the extinct Panthera gombaszoegensis utilising life history data from the modern jaguar Panthera onca. This approach highlighted the potential importance of glacial refugia in the extinction process. Even model refugia the size of the Italian peninsula did not guarantee persistence of a population over a 1000 yr time span, illustrating the role of chance in survival in such a refugium. An area the size of the largest Mediterranean island was unable to support a big cat population for a period of 1000 yr. The models also demonstrated the importance of inbreeding as a mechanism for extinction in refugia. It is suggested that repeated genetic bottlenecks during successive glaciations would tend to remove lethal recessive alleles from the population, increasing the probability of survival in refugia in subsequent glaciations. The history of extinction of large carnivores in the European Quaternary is interpreted in the light of these results. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

条纹斑竹鲨5个地理群体的简单重复序列中间区域分析   总被引：1，自引：0，他引：1  

潘滢  郑利兵  王军 《海洋科学》2018,42(3):31-36

简单重复序列中间区域(inter-simple sequence repeat,ISSR)是一种微卫星类分子标记。为明确条纹斑竹鲨(Chiloscyllium plagiosum)中国群体的遗传多样性和遗传关系,作者利用ISSR技术对福建厦门(XM)、福建平潭(PT)、广东湛江(ZJ)、海南海口(HK)和台湾(TW)5个土著地理群体的条纹斑竹鲨进行了遗传多样性和遗传关系分析。从56对ISSR引物中筛选出13对多态性引物,扩增共获得81个重复性的位点,其中多态性位点57个,多态位点百分率为70.37%。5个群体的多态位点百分率、Nei’s基因多样性和Shannon’s信息指数分别为38.27%~58.02%,0.1353~0.2155和0.2032~0.3193。UPGMA聚类分析表明PT群体首先和XM群体聚类,再与TW群体聚类,最后与ZJ群体和HK群体形成的分支聚类,即形成了与地理距离远近相关的基因交流模式。  相似文献   

Spectral Energy Distribution fitting: Application to Lyα-emitting galaxies     

Eric Gawiser   《New Astronomy Reviews》2009,53(3):50

Spectral Energy Distribution (SED) fitting is a well-developed astrophysical tool that has recently been applied to high-redshift Lyα-emitting galaxies. If rest-frame ultraviolet through near-infrared photometry is available, it allows the simultaneous determination of the star formation history and dust extinction of a galaxy. Lyα-emitter SED fitting results from the literature find star formation rates 3 M yr⁻¹, stellar masses 10⁹ M for the general population but 10¹⁰ M for the subset detected by IRAC, and very low dust extinction, A_V  0.3, although a couple of outlying analyses prefer significantly more dust and higher intrinsic star formation rates. A checklist of 14 critical choices that must be made when performing SED fitting is discussed.  相似文献   

Bio-gentrification: vulnerability bio-value chains in gentrifying neighbourhoods†     

Karen Bridget Murray 《Urban geography》2013,34(2):277-299

In this paper, I develop the concept of “bio-gentrification” as a way to broaden critical theoretical debates on the relationship between gentrification and “social mixing” policies. Bio-gentrification weds urban Marxist political economic insights to the neo-Foucauldian notion of biopower. The former stresses spatial tactics of removal and displacement and value generated through land and property. The latter assesses a wider terrain of spatial tactics, their relationship to knowledge produced about humans as living beings, and their alignment with capitalist urbanization. The Vancouver example illuminates how social mixing “truths” and practices to which they are tied generate value by naturalizing human insecurity in situ and transforming the biological existence of disadvantaged peoples into raw material for profit through a process that can be conceptualized as a “vulnerability bio-value chain.” Bio-gentrification refers to the tension between removal and embedding of disadvantaged peoples and points to the need for a bio-gentrification politics to confront this dynamic.  相似文献   

Research Note—The Ebb and Flow of Temporary Populations: The Dimensions of Spatial-Temporal Distributions of Daytime Visitors in the Netherlands     

《Urban geography》2013,34(4):353-359

In a network society, the increasing fragmentation of individual activity and travel patterns has a major impact on visitors' use of places and spaces throughout the day. The aim of this study is to determine the main dimensions underlying diurnal weekday variations in visitor populations in Dutch municipalities, and to identify the salient spatial and transportation-related features of these municipalities that contribute to the dimensions of these temporary populations. Using the 1998 Netherlands National Travel Survey for six representative one-hour time periods, we performed an exploratory factor analysis to capture the underlying dimensions. The solution comprised one dimension referring to participation in activities, two dimensions related to the size of the territory in which visitor populations operate combined with the use of different transport modes, one dimension expressing the direction in which interlocal movement occurs, and three dimensions capturing different life-cycle stages within the visitor population.  相似文献   

A global mental health opportunity: How can cultural concepts of distress broaden the construct of immobility?     

《Global Environmental Change》2022

(Im)mobility studies often focus on people on the move, neglecting those who stay, are immobile, or are trapped. The duality of the COVID-19 pandemic and the climate crisis creates a global mental health challenge, impacting the most structurally oppressed, including immobile populations. The construct of immobility is investigated in the context of socio-political variables but lacks examination of the clinical psychological factors that impact immobility. Research is beginning to identify self-reported emotions that immobile populations experience through describing metaphors like feeling trapped. This article identifies links in the literature between Cultural Concepts of Distress drawn from transcultural psychiatry and immobility studies. Feeling trapped is described in mental health research widely. Among (im)mobile people and non-mobility contexts, populations experience various mental health conditions from depression to the cultural syndrome, nervios. The connection of feeling trapped to CCD research lends itself to potential utility in immobility research. The conceptualisation can support broadening and deepening the comprehension of this global mental health challenge – how immobile populations’ experience feeling trapped. To broaden the analytical framework of immobility and incorporate CCD, evidence is needed to fill the gaps on the psychological aspects of immobility research.  相似文献   

长牡蛎(Crassostrea gigas)野生与选育群体的微卫星遗传多样性分析     

李妍  姚健涛  张恩烁  孙泽轩  孙国华  李彬  杨建敏  冯艳微  王卫军 《海洋与湖沼》2024,55(2):462-470

为了评估长牡蛎(Crassostrea gigas) 2个壳长性状(掌心形)快速生长选育群体(LY2-K4、LY2-K7)、1个壳高性状(速生型)快速生长选育群体(LY2-K11)和6个野生群体(QHD、LS、HD、ZH、WD、KTD)的遗传多样性和遗传结构, 用21对多态性丰富的微卫星引物对9个长牡蛎群体的269个个体进行了遗传分析。结果显示: 21个微卫星位点共检测出了460个等位基因(N_a),平均等位基因数为21.905; 21个微卫星位点的多态信息含量(PIC)均大于0.5, 具有高度遗传多态性; 选育群体LY2-K11的遗传多样性最低(N_a=13, I=2.128,H_e=0.831, PIC=0.825), 野生群体KTD的遗传多样性最高(N_a=29,I=3.112, H_e=0.941, PIC=0. 938); 189个群体位点组合有66%偏离哈代-温伯格平衡, 表明这些群体存在一定程度的杂合子缺失; 9个群体间的遗传分化指数(F_st)为0.012~0.064, 处于较低的遗传分化水平; AMOVA分析显示遗传变异主要来自于个体内; PCoA分析结果与UPGMA聚类树一致, LY2-K11群体单独聚为一类, QHD和HD群体聚为一类, 其他6个群体聚为一类。综上所述, 长牡蛎3个选育群体和6个野生群体遗传多样性均较高, 遗传分化水平较低; 选育群体LY2-K11多样性略有下降, 选育过程中应保证亲本的数量及质量, 防止因近交衰退造成遗传多样性降低, 苗种抗逆性变差。该结果将为长牡蛎新品种的选育和野生种质资源的保护提供科学指导。  相似文献   

The impact of climate change on the adaptation of marine fish in the Baltic Sea   总被引：1，自引：0，他引：1  

Ojaveer  Evald; Kalejs  Margers 《ICES Journal of Marine Science》2005,62(7):1492-1500

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中国对虾(Fenneropenaeus chinensis)黄、渤海3个野生地理群遗传多样性的微卫星DNA分析   总被引：20，自引：1，他引：20  

刘萍  孟宪红  何玉英  孔杰  李健  王清印 《海洋与湖沼》2004,35(3):252-257

提要运用微卫星DNA技术，以中国对虾渤海湾群体(BH)、辽东湾群体(LD)和海州湾群体(HZ)的3个野生群共计60个个体为实验材料，进行了7个基因位点的遗传参数分析。同时对7对微卫星引物的多态性信息含量(PIC)进行了评估，EN0021位点提供的信息含量低于0.5，其他6对微卫星引物的PIC值均在0.5以上，适于应用于中国对虾的群体分析。结果表明，这7个微卫星位点在中国对虾3个地理群60个样品的分析中共获得了56个等位基因，对3个野生群体的7个基因位点共计21个群体位点进行了杂合度观测值(H0)和杂合度期望值(H0)计算；在Hardy-Weinberg平衡条件下，进行了P检验，发现BH和HZ各有1个群体位点发生平衡偏离，而LD有1个群体位点发生平衡偏离，还有2个群体位点已发生显著平衡偏离。但除此之外，对3个地理群间的遗传分化指数Fst值进行的计算结果表明，BH和LD之间遗传分化较弱，HZ与另2个地理群间则产生了中等程度的分化。从变异贡献率来看，有92.83％的遗传变异来自个体之间，只有7.17％的遗传变异来自群体之间。经过UPGMA聚类，发现BH群体和LD群体的亲缘关系较近，而HZ群体与前两者亲缘关系较远。  相似文献