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Delort E Watanabe N Etoh H Sakata K Ceccaldi HJ 《Marine biotechnology (New York, N.Y.)》2000,2(3):224-230
Effects of lumichrome, l-tryptophan, and curcumin on fouling organisms were examined on panels immersed in a near-shore aquatic environment. These
products showed effective action in aquariums in preliminary screening tests for promoting different steps of fouling. Lumichrome
showed metamorphosis-inducing activity for ascidian larvae (Halocynthia), l-tryptophan was a settlement-inducer for larvae of barnacles (Balanus), and curcumin showed attachment-promoting activity on the blue mussel (Mytilus). In order to establish that these tests are helpful in screening actual fouling or antifouling compounds, we examined the
action of these three compounds in a coastal environment by following the first steps of biofouling, that is, by studying
the quantity of chlorophyll, the number of bacterial cells, and the larvae settled. These experiments on the seashore indicated
that these compounds did not act as promoters for the target organisms; however, they did show promoting effects on some nontarget
organisms.
Received September 30, 1998; accepted September 28, 1999 相似文献
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不同地点蒙古栎群落相似性的研究 总被引:3,自引:0,他引:3
通过13个地点蒙古栎群落物种相似性与两地之间距离的回归比较,发现蒙古栎群落物种相似性的大小一般决定于不同地点之间的地理位置,两地之间距离越近,其相似性越高,反之则越低,但是群落不同的演替阶段也影响群落的相似性。通过分析蒙古栎群落物种组成的差异及物种相似性系数的比较,蒙古栎群落可分为大兴安岭蒙古栎群落、长白山蒙古栎群落、辽西蒙古栎群落和辽冀蒙古栎群落等几种类型。 相似文献
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An investigation into the attachment duration of the tick Ixodes uriae on free-living adult black-legged kittiwakes Rissa tridactyla was carried out at a colony in southeast Scotland. Adult kittiwakes (n = 14) were caught and searched for ticks. Newly attached ticks (n = 31) were marked as was the bird before its release. These birds were recaptured at intervals of two to seven days and the presence or absence of the tick was recorded. The median attachment duration was estimated as 7.7 days (SE = 0.38) and estimated times for 5% and 95% of ticks to become detached were 5.22 days (SE = 0.67) and 9.51 days (SE = 0.58) respectively. Information on tick attachment duration is essential for the development of accurate models of tick population dynamics and patterns of disease transmission. 相似文献
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Manjusha Gupte 《Human ecology: an interdisciplinary journal》2004,32(3):365-382
Women are important stakeholders in natural resource policies since rural women in developing countries are responsible for most of the collection of food, fuel, and firewood for commercial and domestic use. When it comes to the management of these natural resources, gender inequality due to societal traditions could limit the ability of women to participate in policy-making, even when they are not formally excluded. This paper analyzes the effect of gender stratification on women's participation by undertaking an empirical study of a participatory environmental policy program in Indian villages. It endeavors to answer the question of how gender stratification affects participatory environmental policy-making. Using the case study of a community forestry program, it finds that women are still marginalized in decision-making, even in participatory environmental policies. Gender stratification continues to impinge upon forms of democratic decision-making in developing societies. Using facilitating policy tools that seek to empower such marginalized groups would be one way of making participation meaningful for all groups in society. 相似文献
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广东肇庆七星岩石灰岩的植物群落及其与风景区景观关系的研究 总被引:3,自引:0,他引:3
就肇庆七星岩石灰岩的自然环境、植被的主要特征和植物群落11个类型作了论述,并对石灰岩植被的发展与风景区景观的关系作了探讨,提出加强保护、发展植被的建议 相似文献
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Robert G. Garrett 《人类与生态风险评估》2000,6(6):945-963
Almost all metals present in the environment have been biogeochemically cycled since the formation of the Earth. Human activity has introduced additional processes that have increased the rate of redistribution of metals between environmental compartments, particularly since the industrial revolution. However, over most of the Earth's land surface the primary control on the distribution of metals is the geochemistry of the underlying and local rocks except in all but the worst cases of industrial contamination and some particular geological situations. Fundamental links between chemistry and mineralogy lead to characteristic geochemical signatures for different rock types. As rocks erode and weather to form soils and sediments, chemistry and mineralogy again influence how much metal remains close to the source, how much is translocated greater distances, and how much is transported in solutions that replenish ground and surface water supplies. In addition, direct processes such as the escape of gases and fluids along major fractures in the Earth's crust, and volcanic related activity, locally can provide significant sources of metals to surface environments, including the atmosphere and sea floor. As a result of these processes the Earth's surface is geochemically inhomogeneous. Regional scale processes lead to large areas with enhanced or depressed metal levels that can cause biological effects due to either toxicity or deficiency if the metals are, or are not, transformed to bioavailable chemical species. 相似文献
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Larry Ray is Professor of Sociology at the University of Kent Kate Reed is a Lecturer in Sociology at the University of Sheffield 《Ethnic and racial studies》2013,36(2):212-234
Much research into community, racism and racialization has been conducted in metropolitan urban settings. It is only recently that race in rural areas has received some attention. A key theme of existing research on race in rural areas has focused on the issue of racial violence. Drawing on interviews with a variety of ethnic minority groups in East Kent the article will focus on broader issues of race and ethnicity in a semi-rural area. The study explores the meaning of race, ethnicity and belonging in the partially rural setting of East Kent, UK. The article will raise issues around the intersection of the regional and global, the problematic notion of “community”, and the fluidity of racialization in a setting in which many ethnic minorities were transitory and mobile. We conclude by highlighting the ways in which community, racism and racialization are embedded in differentiated discourses and processes. 相似文献
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试论生物对环境的调节作用 总被引:1,自引:0,他引:1
在处理人与自然的战略关系时存在着两种相互对立的观点 :第一种观点认为 ,由于地球位于太阳系合适的轨道上 ,其表面具有独特的有益于生命活动的物理条件。生命系统 (天然的动植物区系 )适应其居住的环境。依靠生命系统本身的作用可以改变环境。通过物种的进化 ,生命系统能适应环境的变化。例如 ,在古代生命系统引发了还原性大气向氧化性大气的转变 ,由此产生了需氧生物 ,而那些厌氧的生物或者灭绝 ,或者转向局部厌氧环境。第二种观点则注重地球环境的物理学上的不稳定性 ,认为地球物理环境正在向与金星或火星类似的没有生命的环境转变 ,而地… 相似文献
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《Anthrozo?s》2013,26(3):249-261
ABSTRACTA 35-item questionnaire (DAQ: Dog Attachment Questionnaire) involving 5-point Likert responses to items designed to measure aspects of attachment to a pet/companion animal dog was constructed. The content was derived from theoretical treatments of adult human attachment, used in a broad sense as equivalent to an affectional bond. Items based on four groupings were modified for a pet dog. Two samples of dog owners (n = 112 and 306, respectively) were used to investigate the factor structure of the questionnaire, using first exploratory and then confirmatory factor analysis (CFA). The questionnaire showed high overall internal consistency, it indicated a high level of attachment to the pets, and factor analysis indicated a four-factor solution, which was replicated using CFA in Sample 2. Three of these factors produced reliable subscales, indicating (1) degree of closeness with the pet; (2) caring and protecting the pet, and companionship; (3) as a secure base and a source of emotional comfort and well-being. In sample 2, Total DAQ scores were positively related to a single-item pictorial measure of attachment to the dog, and were higher for women than men but not associated with age or duration of ownership. 相似文献
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为了复壮扬子鳄野生种群数量,实施养殖扬子鳄放归自然是重要途径之一.通过对人工养殖扬子鳄进行野外放归的试验研究,以探明其在野外环境下活动情况和适应能力.2007年6~11月,采用无线电遥测跟踪、望远镜观察和夜间辅助灯光望远镜观察等方法,对健康的4条5.5年龄和3条2.5年龄的人工养殖扬子鳄在自然环境下活动情况进行观察;在2008和2009年的5月,将这些鳄重捕后测量它们的大小并察看生长情况.结果显示:扬子鳄的释放初期经历了过渡期和争夺领域期2个阶段,20天后处于不同的区域内,具领域特征和营建洞穴行为,能够安全越冬;逐渐恢复野生习性,自我保护的警惕性提高,逃避威胁的能力加强;小龄鳄生长明显,大龄鳄没有明显生长,这与它们所处环境的食物种类有关;鳄性成熟后,能够成功繁殖.总之,人工养殖扬子鳄能够适应相应的自然环境,能够正常生活、生存和繁衍. 相似文献
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Soares AR da Gama BA da Cunha AP Teixeira VL Pereira RC 《Marine biotechnology (New York, N.Y.)》2008,10(2):158-165
Marine invertebrates settle, attach, and/or metamorphose in response to signals from several sources, including seaweeds.
In response to the aquaculture challenge of producing constant numbers of juveniles from cultured species, natural inducers
have been screened for their ability to improve those processes. However, few chemical inducers of attachment of invertebrates
have been identified, and even less of these were secondary metabolites. The goal of this work was to isolate the natural
products responsible for induction activity using bioassay-guided fractionation of the organic extract of the brown seaweed
Stypopodium zonale and the attachment of juveniles of the common brown mussel, Perna perna, as a model. The meroditerpene epitaondiol, identified by comparison of spectral data with the literature, promoted as much
as 4.7 times more mussel attachment compared to controls at the natural concentration found in this alga (0.041% of the crude
extract or 0.012% of algal dry weight). This is the first report showing that a seaweed produces terpenoid compounds as cues
for invertebrate attachment, and future studies evaluating this action on settlement of mussels in the field are expected
to improve aquaculture technology by increasing mussel spat production. 相似文献
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KEITH VICKERMAN 《The Journal of eukaryotic microbiology》1973,20(3):394-404
SYNOPSIS. The ultrastructure of attached Trypanosoma vivax epimastigote clusters in the proboscis of the tsetse fly Glossina fuscipes is described from electron micrographs of thin sections. Some flagellates are attached directly to the lining of the insect's labrum by their flagella, most of which are aligned along the long axis of the proboscis. Other trypanosomes are attached indirectly, their flagella adhering to those of flagellates which are directly attached. Junctional complexes similar to those described from metazoan epithelia are found on the flagellar membrane. A long zonular hemidesmosome attaches the flagellum to the proboscis wall and a series of closely set macular desmosomes link the flagellar membranes of adjacent flagellates. Unlike the trypomastigote stages of T. vivax, more than one row of macular desmosomes may be present along the flagellum-body junction of the trypanosome. It is suggested that all these Junctional complexes serve to buttress the flagellate's attachment to its insect host and so maintain anchorage of the parasite during the fly's blood meals. The ability of the flagellum of trypanosomatids to form Junctional complexes may be a factor contributing to their success as parasites, this adaptation enabling them to multiply while attached to host surfaces. 相似文献
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核基质结合区对转基因表达的影响及其作用机制 总被引:12,自引:1,他引:12
核基质结合区(matrix attachment region,MAR)是一段在体外能与核基质结合的富含AT的DNA序列。研究发现MAR能使染色质形成环状结构;将其连到目的基因二侧构建载体并转至生物体中,发现它能增强基因转录表达水平及稳定性,在一定程度上降低转基因个体或细胞系之间转基因的表达水平的差异,这很可能是减低了基因沉默所致。现对MAR的序列特征、MAR对转基因表达的影响及对转基因效应的影响机制进行综述。 相似文献
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目的调查安徽省阜阳地区居室环境中粉螨的群落组成和多样性。方法于2009年7月,选择100户家庭进行样本采集,每居室环境中取4个采样点,对采集到的地面灰尘、床面灰尘、家具灰尘及衣物灰尘进行粉螨的分离、鉴定、计数和数据分析。结果共检获粉螨3609只,隶属于6科15属,共19种。对4类居室灰尘中粉螨群落多样性分析表明:它们的丰富度指数为0.89~2.09,多样性指数为1.28~1.83,均匀度指数为0.65~0.71。结论粉螨群落的结构及多样性与其生境条件直接相关;阜阳地区人居环境粉螨孳生密度较高(48.5%),应加强防螨措施。 相似文献
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大豆田中大豆蚜天敌昆虫群落结构分析 总被引:1,自引:2,他引:1
为了明确大豆田中大豆蚜Aphis glycines Matsumura天敌昆虫的群落结构特点,采用系统调查法对大豆蚜天敌的种类及数量进行调查。结果表明,大豆蚜天敌昆虫主要有5目11科19种,另外还有一些捕食性蜘蛛。主要优势种为小花蝽Orius minutus、龟纹瓢虫Propylaea japonica、中华草蛉Chrysopa sinica以及蚜小蜂Aphelinus sp.和异色瓢虫Leis axyridis,捕食性蜘蛛其中小花蝽的相对丰盛度达到0.26以上。小花蝽和龟纹瓢虫发生较早,是大豆蚜发生初期的主要控制因素。物种多样性、均匀度、丰富度、物种数和个体数整体趋势表现为先增加后降低,在7、8月达最大;而优势集中性和优势度则表现为先降低后增加的趋势,群落较稳定。 相似文献
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J. A. Cuesta E. González-Ortegón A. Rodríguez F. Baldó C. Vilas P. Drake 《Hydrobiologia》2006,557(1):85-95
Monthly samples were taken from May 1997 to March 2002 at three sampling sites within the last 32 km of the Guadalquivir Estuary. Twenty-four decapod crustacean species were recorded of which Crangon crangon (Linnaeus), Melicertus kerathurus (Forskal), and Palaemon spp. represented 99% of all collected individuals. These three dominant species showed a similar seasonal density pattern even though peaks in M. kerathurus were lower. Their densities were positively correlated (p < 0.01) with water temperature and salinity, but negatively with turbidity. The highest correlation corresponded to temperature in Palaemon spp. and to salinity in C. crangon and M. kerathurus. Therefore, the total estuarine decapod density also showed a regular seasonal pattern having the lowest figures in late autumn and winter and the highest in spring and summer. In addition, it was positively correlated with water temperature and salinity, but negatively with turbidity. Density decreased upstream, mainly due to the higher density of C. crangon and M. kerathurus in more saline waters. Non-metric multi-dimensional scaling ordination of samples also indicated a regular seasonal change in the community, even though inter-year differences between dry and rainy winters were especially great. The first ordination axis was significantly correlated with environmental variables, while the second axis seemed to split samples up following seasonal community changes in species’ composition and dominance. 相似文献
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Jorge Wagensberg 《Biology & philosophy》2000,15(4):493-508
Some real objects show a very particular tendency: that of becomingindependent with regard to the uncertainty of their surroundings. This isachieved by the exchange of three quantities: matter, energy andinformation. A conceptual framework, based on both Non-equilibriumThermodynamic and the Mathematical Theory of Communication is proposedin order to review the concept of change in living individuals. Three mainsituations are discussed in this context: passive independence inconnection with resistant living forms (such as seeds, spores, hibernation,...), active independence in connection with the life span of aliving individual (whether an ant or an ant farm), and the newindependence in connection with the general debate of biological evolution. 相似文献
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《Free radical research》2013,47(4):279-287
Copper ions have been suggested to play a role in the non-covalent glycosylation (glycation) of proteins via transition metal-catalysed oxidations. We have further investigated “autoxidative glycosylation” by comparison of the behaviour of dog and bovine serum albumin with respect to the oxidative reactions of glucose and ascorbate. The proteins possess similar numbers of total amino residues available for glucose attachment but dog serum albumin contains fewer histidine groups and also lacks a high affinity copper-binding site. We find that the higher copper-binding capacity of bovine serum albumin is reflected in a lower rate of ascorbate oxidation as well as less protein oxidative damage than is the case for dog serum albumin. We also observe that modification of bovine serum albumin histidine groups by diethylpyrocarbonate enhances ascorbate-mediated protein fluorophore formation. 相似文献