959 resultados para PN1997.2 W35 2008


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In June 2008, the NOAA National Ocean Service (NOS), in conjunction with the EPA National Health and Environmental Effects Laboratory (NHEERL), conducted an assessment of the status of ecological condition of soft-bottom habitat and overlying waters within the boundaries of Stellwagen Bank National Marine Sanctuary (SBNMS). The sanctuary lies approximately 20 nautical miles east of Boston, MA in the southwest Gulf of Maine between Cape Ann and Cape Cod and encompassing 638 square nautical miles (2,181 km2). A total of 30 stations were targeted for sampling using standard methods and indicators applied in prior NOAA coastal studies and EPA’s Environmental Monitoring and Assessment Program (EMAP) and National Coastal Assessment (NCA). A key feature adopted from these studies was the incorporation of a random probabilistic sampling design. Such a design provides a basis for making unbiased statistical estimates of the spatial extent of ecological condition relative to various measured indicators and corresponding thresholds of concern. Indicators included multiple measures of water quality, sediment quality, and biological condition (benthic fauna, fish tissue contaminant levels). Depths ranged from 31 – 137 m throughout the study area. About 76 % of the area had sediments composed of sands (< 20 % silt-clay), 17 % of the area was composed of intermediate muddy sands (20 – 80 % silt-clay), and 7 % of the sampled area consisted of mud (> 80 % siltclay). About 70 % of the area (represented by 21 sites) had sediment total organic carbon (TOC) concentrations < 5 mg/g and all but one site (located in Stellwagen Basin) had levels of TOC < 20 mg/g, which is well below the range potentially harmful to benthic fauna (> 50 mg/g). Surface salinities ranged from 30.6 – 31.5 psu, with the majority of the study region (approximately 80 % of the area) having surface salinities between 30.8 and 31.4 psu. Bottom salinities varied between 32.1 and 32.5 psu, with bottom salinities at all sites having values above the range of surface salinities. Surface-water temperatures varied between 12.1 and 16.8 ºC, while near-bottom waters ranged in temperature from 4.4 – 6.2 ºC. An index of density stratification (Δσt) indicated that the waters of SBNMS were stratified at the time of sampling. Values of Δσt at 29 of the 30 sites sampled in this study (96.7 % of the study area) varied from 2.1 – 3.2, which is within the range considered to be indicative of strong vertical stratification (Δσt > 2) and typical of the western Gulf of Maine in summer. Levels of dissolved oxygen (DO) were confined to a fairly narrow range in surface (8.8 – 10.4 mg/L) and bottom (8.5 – 9.6 mg/L) waters throughout the survey area. These levels are within the range considered indicative of good water quality (> 5 mg/L) with respect to DO. None of these waters had DO at low levels (< 2 mg/L) potentially harmful to benthic fauna and fish.

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The intent of this field mission was to continue ongoing efforts: (1) to spatially characterize and monitor the distribution, abundance and size of both reef fishes and conch within and around the waters of the Virgin Islands National Park (VIIS) and newly established Virgin Islands Coral Reef National Monument (VICR), (2) to correlate this information to in-situ data collected on associated habitat parameters, (3) to use this information to establish the knowledge base necessary for enacting management decisions in a spatial setting and to establish the efficacy of those management decisions. This work is supported by the National Park Service and NOAA’s Coral Reef Conservation Program’s Caribbean Coral Reef Ecosystem Monitoring Project. The report highlights the successes of this mission.

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低温威胁水稻的生产,其中苗期和生殖阶段对寒害是最敏感的时期。在苗期,阶段性冷害使水稻幼苗生长延迟,甚至造成烂秧现象;在生殖阶段,无法预测的突然降温会导致水稻花粉不育,并致使水稻大幅减产。因此,对水稻逆境胁迫调控的分子机制的深入研究在理论和实践上具有重要的意义。本研究从东乡野生稻、栽培稻及其杂交后代的低温芯片中筛选对低温响应基因的分析着手,对其中一个受低温诱导上调的基因OsMYB3R-2 作进一步研究。生物信息学的分析表明OsMYB3R-2 编码一个R1R2R3 MYB 蛋白,利用基因枪瞬时转化法、酵母GAL4 系统和电泳迁移率变动分析发现OsMYB3R-2 蛋白能够定位在细胞核中、具有转录激活和DNA 结合特性,表现为MYB 转录因子的典型特征。 超表达OsMYB3R-2 的转基因水稻呈现幼苗的矮化和生长相对滞后的表型,对低温胁迫具有耐受性。盐抑制水稻种子的萌发,与野生型和反义的株系相比,OsMYB3R-2 超表达株系的萌发对盐敏感,表现为萌发过程及萌发之后幼苗的生长更加滞后。而OsMYB3R-2 转基因株系对干旱处理敏感。为了进一步寻找OsMYB3R-2 蛋白的靶序列及其调控的靶基因,我们利用电泳迁移率变动分析发现OsMYB3R-2 能够与有丝分裂特异的激活子(mitosis-specific activator)元件特异结合。在低温条件下,OsMYB3R-2 超表达能够激活水稻G2/M 期特异基因的表达,主要包括OsCycB1;1、OsCycB2;1、OsCycB2;2 和OsCDC20.1 等。另一方面,OsMYB3R-2 超表达能够增加根尖细胞的有丝分裂指数,这进一步说明OsMYB3R-2 参与了水稻细胞周期调控。EMSA、RT-PCR 和流式细胞仪分析的结果表明OsMYB3R-2 通过激活其靶基因OsCycB1;1 的表达参与水稻对低温胁迫的调控,该过程由细胞周期介导。 为了研究OsMYB3R-2 与水稻DREB/CBF 途径的关系,我们分析了转基因水稻中DREB/CBF 类基因及其可能调控的下游基因与OsMYB3R-2 的关系,RT-PCR 的结果表明超表达转基因植物中DREB 表达未见明显变化,而其下游基因OsCPT1 在低温条件下被激活表达。同时,转基因植物在低温条件下脯氨酸水平显著提高。这说明OsMYB3R-2 可能在水稻DREB/CBF 途径的下游参与调控。 总之,OsMYB3R-2 基因的超表达赋予转基因水稻在苗期对低温胁迫具有耐受性,并呈现矮化和生长滞后的表型。OsMYB3R-2 蛋白行使R1R2R3 MYB 转录因子的功能,在体外能够结合OsCycB1;1 和OsKNOLLE2 基因启动子中有丝分裂特异的激活子元件,在低温条件下激活了G2/M 期特异基因的表达,这些基因包括OsCycB1;1、OsCycB2;1、OsCycB2;2 和OsCDC20.1。低温条件下,在OsMYB3R-2 转基因超表达株系中OsCPT1 基因的转录被激活,细胞的游离脯氨酸的含量也显著增高。这些结果都表明OsMYB3R-2 基因在水稻的冷胁迫信号途径中起重要的作用,该过程受细胞周期及DREB/CBF 途径介导。 我们的实验结果暗示水稻对低温的耐受是通过分生组织细胞周期调控完成的,这个过程由OsMYB3R-2 等关键基因控制。

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Between July 2005 and February 2008, ten Catch Assessment Surveys (CASs) were conducted at 54 pre-selected fish landing sites in the Ugandan part of Lake Victoria comprising approximately 10% of all landing sites in each of the 11 districts sharing the lake. The CASs were conducted following regionally harmonised Standard Operating Procedures (SOPs). This report covers the CAS conducted in February 2008 and puts into context the trends generated by results of the previous surveys. The catch rates of Nile perch in gillnetting boats with motor/sail, reduced from 26.9 kg boat-1 day-1 in August 2007 to 22.8 kg boat-1 day-1 in February 2008. Whereas the catch rates of paddle Sesse boats remained more or less the same as in August 2007. The Nile perch catch rates of the long line fishery of the boats using motor/sail was similar, 35 and 36 kg boat-1 day-1 in August 2007 and February 2008 respectively but the catch rates of paddle Sesse boats using long lines showed some more increase from 19 to 22 kg boat (-1) day (-1). In the tilapia fishery, the catch rates of the parachute boats using gillnets showed further decrease in a row from 12.6 kg boat-1 day-1 in December 2006, 11.6 kg boat-1 day-1 in March 2007, 11.2 kg boat-1 day-1 in August 2007 and 10.0 kg boat-1 day-1 in February 2008. The overall impact of reduced catch rates in the predominant effort groups, e.g. gillnetting boats using motor/sail in the Nile perch fishery and Parachute boats using gillnets in the tilapia fishery overshadowed the increases in less dominant effort groups and resulted in the lowest monthly catch estimates recorded in the surveys conducted since 2005. Whereas there was a clear downward trend in the Nile perch catch rates of boats using gillnets, which corroborates with the information of declining stocks from the recent Acoustics surveys, the catch rates in the long line fishery remained stable and even somewhat increasing in the last four surveys. The factors that maintain high catches against reduction of fish biomass in the long line fishery and their effects on sustainability of the Nile perch fishery should be investigated further. The Mukene fishery, characterised by large fluctuations in the catch rates did not show much change in the last two surveys in August 2007 and February 2008 and the annual catch estimates showed an overall increase of 7% from 2005 to 2007. The Mukene fishery in the Ugandan waters of Lake Victoria remained a near shore fishery in which paddle Sesse boats using small seines or scoop nets were the dominant craft.

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During the reporting period, NaFIRRI realigned its projects under ARTP II extension to focus on: 1. Determination of appropriate technologies and methods for harvesting and conservation of fish species in the Albert and Kyoga Systems 2. Impact of policies and technologies on livelihoods 3. Generation of knowledge for the management of aquatic invasive weeds and their hot spots in Lakes Albert and Kyoga 5. Determination of environmental factors influencing productivity for fisheries in Lakes Albert and Kyoga Systems 6. MSI - Nile perch project 7. Adaptation and Facilitating Dissemination of Appropriate technologies for harvesting Commercial Species 8. Identification of fish species suitable for culture and marketing, and promotion of their commercial culture in the Eastern AEZ.

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The Hainan gibbon (Nomascus hainanus) is one of the most endangered primates in the world, confined to mature natural forest in Hainan Island, China. We assessed changes in habitat condition on the island between 1991 and 2008, using vegetation maps generated by remote-sensing images. We defined forest suitable for gibbons based on composition, tree size and canopy cover. During the 17-year period, the area of suitable gibbon forest decreased by 540 km(2) (35%) across the whole island, and by 6.3 km(2) (7%) in the locality of the sole remaining gibbon population at Bawangling National Nature Reserve. The forest patches large enough (>1 km(2)) to support a gibbon group decreased from 754 km(2) to 316 km(2) in total area, and from 92 to 64 in number. Suitable natural forest was mainly replaced by plantations below 760 m, or degraded by logging, grazing and planting of pines above 760 m. Meanwhile, forests in former confirmed gibbon areas became more fragmented: mean area of patches decreased by 53%. We mapped the patches of natural forest in good condition which could potentially support gibbons. We recommend a freeze on further expansion of plantations between core patches at Bawangling, Jiaxi-Houmiling and Yinggeling Nature Reserves in accordance with forest protection regulations; establishment of nature reserves in currently unprotected natural forest patches elsewhere in line with the local government's nature reserve expansion policy; and active natural-forest restoration between remaining fragments at Bawangling. (C) 2010 Elsevier Ltd. All rights reserved.

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Cyclooxygenase-2 (COX-2, encoded by the gene prostaglandin-endoperoxide synthase 2, PTGS2) is a key enzyme in the conversion of arachidonic acid to prostaglandins. The prostaglandins produced by COX-2 are involved in inflammation and pain response in diff

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Leber hereditary optic neuropathy (LHON) is the most extensively studied mitochondrial disease, with the majority of the cases being caused by one of three primary mitochondrial DNA (mtDNA) mutations. Incomplete disease penetrance and gender bias are two

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A key issue in the fabrication of Terfenol-D 2-2 composites with internal magnetic field biasing is the selection of appropriate constituent materials to obtain high magnetostriction while keeping optimum magnetomechanical properties. The fabrication process is costly and time consuming and, therefore, numerical methods to predict their properties are useful. In this paper, finite element analysis (FEA) of the magnetostriction of such composites has been carried out using the commercial package ABAQUS. It has been shown that composites fabricated using Nd2Fe14B for the permanent magnetic material layers possess the highest internal fields within the Terfenol-D layers, although the overall strain of these composites is limited to approximately 800 × 10-6 due to the high elastic modulus of Nd2Fe14B. Simulations showed that the strain can be enhanced by choosing a different material with a lower elastic modulus for the permanent magnetic layer even though the internal field is lower. The simulations showed that the strain can increase by 12% if the Nd 2Fe14B layer is substituted by SmCo5; by 23% if it is substituted by Sm2Co17; and by 35% if it is substituted by Alnico. © 2008 IEEE.

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利用微宇宙系统研究了不同浓度的Hg2+、Cd2+单一及复合处理下,苦草对这三种胁迫的响应。三种胁迫下,3d内苦草现存量增加百分比与金属离子浓度间显著负相关,其中在[Hg2+]或[Hg2++Cd2+]([Hg2+]/[Cd2+]=1)>5μmol/L时,2~3d可致死;总生产力、净生产力、呼吸强度以及叶绿素含量均随着金属离子浓度的增加而下降,同时叶绿素含量还随着胁迫时间的延长而降低,但上述四个指标在低浓度胁迫时常略有升高;可溶性蛋白含量在[Hg2+]或[Hg2++Cd2+]≤2.5μmol/L、以及[Cd2

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研究了金属离子Zn2+,Co2+和Mn2+对复合垂直流人工湿地基质生物膜脱氢酶活性和多糖含量的影响.结果表明,在生物膜混合液中添加Zn2+能在短时间内(6h)迅速提高生物膜的酶活性,增加多糖含量,浓度为2mg/L的Zn2+可以在较长时间(72h)内保持生物膜的酶活性并且促进多糖的积累.Co2+和Mn2+对生物膜脱氢酶活性及多糖含量的影响较为相似.当Co2+浓度<1mg/L、Mn2+浓度<2mg/L条件下,6h时,对脱氢酶活性呈现了不同程度的促进作用,但随着Co2+和Mn2+离子浓度的增加,对脱氢酶活性的影