209 resultados para 215
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Crustacean haemocytes play important roles in the host immune response including recognition, phagocytosis, melanization, cytotoxicity and inter-cellular signal communication. Expressed sequence tags (ESTs) analysis is proved to be an efficient approach not only for gene discovery, but also for gene expression profiles performance. In order to further understand the innate immune system and defense mechanisms of Chinese shrimp at molecular level, complementary DNA library is constructed from the haemocyte tissue of Fenneropenaeus chinensis. A total of 2371 cDNA clones are successfully sequenced and the average sequence length is 460 bp. About 50% are identified as orthologs of known genes from other organisms by BLASTx and BLASTn program. By sequences comparability and analysis, 34 important genes including 177 ESTs are identified that may be involved in defense or immune functions in shrimp based on the known knowledge. These genes are categorized into five categories according to their putative functions in shrimp immune system: 13 genes are different types of antimicrobial peptides (AMP, penaeidin, antilipopolysaccharide factor, etc.), and their proportion is about 3 8%; 11 genes belong to prophenoloxidase system (prophenoloxidase, serine proteinase, serine proteinase inhibitor, etc.), and their proportion is about 32%; five genes have high homology with clotting protein (lectin, transglutaminase, etc), and their proportion is about 15%; three genes may be involved in inter-cell signal communication (peroxinectin, integrin), and their proportion is about 9%; two genes have been identified to be chaperone proteins (Hsc70, thioredoxin peroxidase), and their proportion is about 6%. These EST sequences enrich our understanding of the immune genes of F chinensis and will help farther experimental research into immune factors and improve our knowledge of the immune mechanisms of shrimp. (c) 2007 Elsevier B.V. All rights reserved.
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Two Large-insert genomic bacterial artificial chromosome (BAC) libraries of Zhikong scallop Chlamys farreri were constructed to promote our genetic and genomic research. High-quality megabase-sized DNA was isolated from the adductor muscle of the scallop and partially digested by BamH I and Mbo I, respectively. The BamH I library consisted of 53 760 clones while the Mbo I library consisted of 7 680clones. Approximately 96 % of the clones in BamH I library contained nuclear DNA inserts in average size of 100 kb, providing a coverage of 5.3 haploid genome equivalents. Similarly, the Mbo I library with an average insert of 145 kb and no insert-empty clones, thus providing a genome coverage of 1.1 haploid genome equivalents.
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The morphology of the beach backshore and foreshore at Huiquan Bay, Qingdao, China, is characterized by a single intertidal sandbar system with a spring tide range of 4.59 m. The beach was measured with a laser total station of Leica TPS402. Contours of the beach were generated using data collected in March and November 2005. The survey method provided 2 mm measuring accuracy and 4-10 m horizontal spacing. The net accretion volume of the foreshore was about 11, 215 m(3) from March to November. After sand sculpture activity, the axis of the sand trough migrated onshore from about 3.5 m to 17.5 m on the foreshore beach in November. At the same time, the axis of the sandbar crest migrated onshore no more than 42.25 m on the northwest foreshore; and it migrated offshore no more than 23.75 m on the southeast foreshore. On the northwest and southeast foreshore beach, two strips of erosion areas with a thickness of 0-0.2 m appeared on the sandbar crest. Accretion occurred at the bottom of the sand trough with a thickness of similar to 0.2-0.6 m. The sandbar height decreased after sand sculpture activity, and it was no more than 0.7 m in March and 0.6 m in November. Human activities, such as sand digging on the sandbar crest during sand sculpture activity, also can disturb the beach morphology of intertidal bar systems. This phenomenon also was validated by comparison of beach morphology, the results of a color artificial tracer experiment and a sediment transportation trend prediction.
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The mineralogical and geochemical characteristics of Fe-oxyhydroxide samples from one dredge station (long. 103 degrees 54.48'W, lat. 12 degrees 42.30'N, water depth 2655 m) on the East Pacific Rise near lat 13 degrees N were analyzed by XRD, ICP-AES, and ICP-MS. Most Fe-oxyhydroxides are amorphous, with a few sphalerite microlites. In comparison with Fe-oxyhydroxides from other fields, the variable ranges in the chemical composition of Fe-oxyhydroxide samples are very narrow; their Fe, Si, and Mn contents were 39.90%, 8.92%, and 1.59%, respectively; they have high Cu (0.88%-1.85%) and Co (65x10(-6)-704x10(-6)) contents, and contain Co+Cu+Zn+Ni > 1.01%. The trace-element (As, Co, Ni, Cu, Zn, Ba, Sr) and major-element (Fe, Ca, Al, Mg) contents of these samples are in the range of hydrothermal sulfide from the East Pacific Rise near 13 degrees N, reflecting that this type of Fe-oxyhydroxide constitutes a secondary oxidation product of hydrothermal sulfide. The Fe-oxyhydroxide samples from one dredge station on the East Pacific Rise near 13 degrees N are lower in Sigma REE (5.44x10(-6)-17.01x10(-6)), with a distinct negative Ce anomaly (0.12-0.28). The Fe-oxyhydroxide samples have similar chondrite-normalized rare-earth-element (REE) patterns to that of seawater, and they are very different from the REE composition characteristics of hydrothermal plume particles and hydrothermal fluids, showing that the REEs of Fe-oxyhydroxide are a major constituent of seawater and that the Fe-oxyhydroxides can become a sink of REE from seawater. The quick settling of hydrothermal plume particles resulted in the lower REE content and higher Mn content of these Fe-oxyhydroxides, which are captured in part of the V and P from seawater by adsorption. The Fe-oxyhydroxides from one dredge station on the East Pacific Rise near 13 degrees N were formed by secondary oxidation in a low temperature, oxygenated environment. In comparison with the elemental (Zn, Cd, Pb, Fe, Co, Cu) average content of hydrothermal sulfide samples from the East Pacific Rise near 13 degrees N, the Zn, Cd, and Pb contents of the Fe-oxyhydroxides are lower, and their Fe, Co, and Cu contents are higher.
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The typology and flux of settling particulate matter (SPM) were investigated based on sediment trap sampling at six typical stations in the Yellow Sea and the East China Sea. The settling particulate matter in the neritic seas was sorted into three categories, lithogenic particles, living organisms, and particle aggregates. The mass of individual organisms is an important portion of particulate matter in the neritic waters. The aggregates contain six types, mucus aggregates, fecal pellets, diatom aggregates, silicoflagellate aggregates, tintinnids, and miscellaneous aggregates, of which the silicoflagellate aggregates and tintinnids are the most abundant in the Yellow Sea and the East China Sea. High particle fluxes, such as 215 to 874 g m(-2). day(-1) SPM in the bottom layer, were found at three stations where the water was well mixed, and the maximum flux was detected in the boundary area between the Yellow Sea and the East China Sea, where a wide nepheloid layer was present. Hence, particle flux in neritic waters can be easily shifted by water turbulence. The net vertical flux (123 to 961 mg C day(-1)), the contribution of lateral advection to resuspension flux (5 to 76%), and the particulate organic carbon export ratio (18 to 60%) were estimated for the other three stations where the water was stratified. The highest values were all found in the upwelling area off the Zhejiang coast, suggesting that the area of high productivity provides a high net vertical flux of SPM. (C) 2010 Elsevier Ltd. All rights reserved.
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The economic loss caused by the storm surge disasters is much higher than that caused by any other marine disaster in China, the loss from the severe storm surge disaster being the highest. Statistics show that there were 62 typhoon landings over the east-southeast coast of China since 1990, three of which, occurring in 1992, 1994 and 1997, respectively, caused the most severe damage. The direct economic losses due to these events are 9.3, 17.0 and 30 billion yuan (RMB, or about 1.7, 2.6 and 3.8 billion USD, respectively), which is much greater than the loss of 5.5 billion yuan (RMB) on an average every year during the 1989-1991 period. This paper makes a comparative analysis of the damage caused by the three events and presents an overview of progress of precautions against storm surge disaster in China. The suggested counter measures to mitigate the loss from the severe storm surge disasters in China is as follows: (1) Raise the whole society awareness of precaution against severe storm surge disaster; (2) Work out a new plan for building sea walls; (3) Improve and perfect the available warning and disaster relief command system; (4) Develop the insurance service in order to promptly mitigate the loss caused by severe storm surge disaster event.
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本文分别提取了中国对虾、中华绒螯蟹、鹰爪虾和蓝对虾的眼柄总RNA。用无DNA污染的眼柄总RNA为模板,根据日本对虾的MIH设计兼并引物P1和P2,进行RT-PCR扩增,在适宜的反应条件下,均分别得到一特异性的产物。以蓝对虾基因组DNA为模板的PCR扩增也能得到一与特异性cDNA片段大小相似的特异性的DNA片段。分别将这些片段亚克隆到载体中进行测序,测得中国对虾特异性cDNA片段由203个碱基组成,中华绒螯蟹、鹰爪虾、蓝对虾的特异性cDNA片段及蓝对虾的特异性DNA片段由215个碱基组成,其中蓝对虾特异性cDNA与由蓝对虾的基因组DNA扩增得到的特异性DNA片段的碱基序列几乎完全相同。利用互联网上的在线工具Fasta3查找这些cDNA推定的氨基酸序列的相似序列,可以发现大量的甲壳动物的CHH家族的神经肽与它们相似。在所有的相似序列中,分别由中国对虾、中华绒螯蟹、鹰爪虾和蓝对虾的特异性cDNA片段推定的氨基酸序列与蜕皮抑制激素(MIH)的相似度最高,这一结果提示分别由中国对虾、中华绒螯蟹、鹰爪虾和蓝对虾的眼柄特异性cDNA片段推定的氨基酸序列可能是这四种甲壳动物的MIH片段。根据核苷酸数据和氨基酸数据,比较这四种甲壳动物的MIH以及已发表的六种MIH之间的相似度,同时分析这十种MIH的系统进化关系,结果是蓝对虾、鹰爪虾和中华绒螯蟹的MIH相似性较高,亲缘关系较近,这与物种的系统演化不相符。
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沉积物再悬浮作为一个比较普遍的物理现象,对浅海生态系统污染物的生物地球化学循环具有强烈的干扰作用。本研究以我国北方重要养殖海湾——桑沟湾为研究对象,从物理、化学、生物三个角度出发,研究了沉积物再悬浮的发生过程以及再悬浮介质-沉积物的源汇转换角色及其与养殖藻类的关系,构建了波流耦合模型和再悬浮颗粒物浓度预测数学模型。主要研究结果如下: 1)桑沟湾的海湾动力比约为1.54,沉积物具有发生再悬浮的潜在动力条件;推导出波流耦合切应力的计算公式。 2)悬浮颗粒物浓度(SSC)与浊度(NTU)之间符合线性方程SSC=15.908×ln(NTU)+7.0888(n=33,R2=0.7209);碎屑有机碳库是桑沟湾养殖生态系统中最大的有机碳库,占总POC库储量的81.87%。 3)沉积物再悬浮的临界切应力在0.059 N/m2左右,耦合切应力与悬浮颗粒物浓度符合方程= 238.06 SSC + 25.215(n=25,R2 = 0.7298);最大剪切深度可达8.81 cm;桑沟湾沉积物再悬浮通量的数量级在10-5~10-6 kg·m-2·s-1之间,再悬浮临界风速约为5.51 m/s,全年约有171天沉积物处于再悬浮状态;构建了沉积物再悬浮颗粒物浓度预测数学模型。 4)桑沟湾表层沉积物总氮的含量范围313.09~1094.44µg/g,有机氮是总氮的主要形态,平均占总氮的60.86%;交换态氮是无机氮的主要形式,平均占无机氮的71.40%,交换态氮中NO3--N的含量最大;桑沟湾表层沉积物的TOC/TN比值为9.38,表明沉积物中有机质具有混合来源的特征;无机磷是桑沟湾表层沉积物中磷的主要形态,平均占总磷的73.33%,钙结合磷是无机磷的主要赋存形态;表层沉积物中潜在生物有效性磷的含量占总磷的86.54%,具有很强的释磷潜力。桑沟湾重金属的潜在生态危害指数RI约为36.17,表明重金属的潜在生态危害轻微。 5)再悬浮过程中沉积物春季表现为氮磷源,释放溶解无机氮和磷酸盐;夏、秋季表现为氮汇磷源,释放磷酸盐而吸附溶解无机氮;冬季表现为氮磷汇,吸附磷酸盐和溶解无机氮。
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The chemical species of iodine in seven marine algae Codium fragile, Ulva pertusa, Monostroma nitidum, Gracilaria confervoides, Sargassum Kjellmanianum, Dictyopteris divaricata and Laminaria japonica were studied using neutron activation analysis combined with chemical separation. The contents of total iodine, water-soluble iodine, soluble organic iodine, I- and IO3- were determined. The results indicate that the chemical species and contents of iodine in various algae are remarkably different. The highest iodine content of 734 mg/kg (wet basis) was found in Laminaria japonica, with 99.2% of the total iodine being water soluble. The iodine contents of the other six algae are lower and soluble iodine makes up 16-41% of the total. In the aqueous leachate, iodine is mainly I-, which amounts to 61-93% of total water-soluble iodine; the percentages of organic iodine making up 5.5-37.4%, while the contents of IO3- are the lowest, 1.4-4.5%. This result suggests that the mechanism of iodine enrichment is different for various algae and that its bioavailability varies as well. (C) 1997 Elsevier Science B.V.
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采用薄层色谱法(TLC)和反相高效液相色谱法(RP-HPLC)对藏药材圆萼刺参中的芦丁,熊果酸和齐墩果酸进行定性和定量的分析.定性分析:TLC法检定芦丁和熊果酸和齐墩果酸成分,薄层色谱条件是以V(乙酸乙酯)∶V(丁酮)∶V(甲酸)∶V(水)=10∶6∶1∶2为展开剂,喷以10 g/L.NaNO_2的1%甲醇溶液在105℃检定芦丁,以V(CHCl3)∶V(乙酸乙酯)=1∶1为展开剂,喷以V(H2SO4)∶V(甲醇)=1∶2溶液在105℃检定熊果酸和齐墩果酸.定量分析:RP-HPLC法测定圆萼刺参中芦丁,流动相:V(甲醇)∶V(0.4%H_3PO_4溶液)=38∶62;检测波长340 nm;RP-HPLC法测定熊果酸和齐墩果酸,流动相:V(甲醇)∶V(0.2%H_3PO_4)溶液=85∶15;检测波长215 nm;圆萼刺参中的齐墩果酸,在本种植物中首次发现.
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对江河源区不同建植年限人工草地(2龄、4龄、6龄)土壤养分、微生物数量及酶活性进行研究.结果表明:不同建植年限人工草地土壤养分随着建植年限的增加呈"V"型规律变化,其中人工2龄草地土壤养分含量最高,6龄草地土壤养分含量虽不及2龄草地高,但均明显高于4龄草地.土壤细菌和放线菌数量与土壤养分变化规律一致,真菌数量随建植年限的增加呈降低趋势,土壤脲酶、过氧化氢酶和中性磷酸酶活性与细菌、放线菌和土壤养分变化规律相同.同时,土壤养分、微生物数量和酶活性变化均具有明显的空间层次现象,即随土层的加深呈降低的趋势.经典型相关分析表明,土壤细菌与土壤有机质、全氮、速效钾和pH值之间相关性最好,脲酶和过氧化氢酶活性与土壤有机质、全氮、速效氮、速效钾和pH值之间相关性最好,故土壤微生物数量和酶活性可作为评价土壤肥力的指标.
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为探讨高原鼠兔家群空间领域的季节特征,分别于2005年和2006年的5~8月,在青海省玛沁县,采用标志重捕法和最小多边形面积法对其家群巢区和核域进行了研究.结果表明,不同季节,高原鼠兔巢区和核域面积存在显著差异.5、6月份,成体巢区面积显著大于幼体,但二者核域面积却无显著差异;7月份,成体与第1胎幼体巢区及核域面积均显著大于第2胎.5、6月份雄性成体巢区显著大于7、8月份,6、7月份雌性成体巢区显著大于5月和8月份.巢区及核域面积均与家群个体数呈极显著性正相关关系,说明季节和家群结构均可对高原鼠兔空间领域产生重要作用。
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对青藏高原东部麻花艽(Gentiana straminea)海北居群的传粉生态学进行了3a连续的观察和实验。试验表明自然去雄、人工自交和杂交处理均结实,而人工去雄套袋和自然套袋不结实。麻花艽自交亲合,但必须依赖传粉媒介才能完成授粉过程,不存在无融合生殖。野外捕捉到14种访花昆虫,它们分别属于2个纲,7个目,8个科。观察和分析了各种昆虫的访花行为后,认为苏氏熊蜂(Bombus sushikini)是麻花艽有效而稳定的传粉者。测量表明麻花艽花蜜通道的深度和苏氏熊蜂的舌长基本吻合。苏氏熊蜂的访花频率在lO:00~12:00,13:00~15:00和16:00~18:OO时间段没有差别,单花的访花频率为0.005次/(花·rain)。和其它高山植物相比,青藏高原高山植物麻花艽的访花频率较高。熊蜂传粉和高频率的访花维持了麻花艽在极端寒旱的青藏高原环境下的有性生殖。此外,高频率的访花对于维持该地区高山植物的生殖保障具有重要的现实意义,但是否具有普遍性,还有待研究更多的高山代表类群。
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在青藏高原探讨不同生态系统碳平衡规律及其影响因子并揭示其对全球含碳温室气体变化的影响与响应 ,有重要的现实意义和理论价值。分别在海北高寒草甸生态站、贡嘎山森林生态站和拉萨农业生态站用静态箱法进行了土壤CO2 排放的试验研究。土壤CO2 排放速率日平均值为草甸215.87~329.68mgCO2m -2h -1 ,森林713.72~2102.56mgCO2m -2h -1 ,农田913.05~1135.83mgCO2m -2h-1。土壤碳排放速率日变化 ,在农田和高寒草甸区表现为单峰型 ,均以地方时8∶00~16∶00最高 ,0∶00~8∶00最低。草甸、农田土壤碳排放随着牧草、作物生长发育的加速而逐渐增加 ,越接近成熟 (或枯黄期 )其值越低 ,林区以6~9月的生长旺季为最高。土壤碳排放与温度之间有较好的相关性 ,温度是影响土壤碳排放的重要因子,全球变暖有可能引起高原土壤碳排放的增加。
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本论文以创新课题“家用服务机器人的研究开发”为背景,对全数字电机伺服驱动系统进行了深入的研究,在此基础上提出了伺服驱动系统的总体设计方案,参与了硬件系统各子模块的设计与调试,完成了软件伺服控制,最终实现了基于CAN总线的全数字伺服驱动系统。论文结合开发的上位机测试软件进行了实验研究,取得了比较理想的实验结果。 本文以该系统为平台,对伺服驱动系统中的难点和热点问题进行了研究,针对这些问题,提出了以下系统设计和实现的新方法和新思路: 1. 将数字信号处理器DSP和现场总线CAN应用到伺服驱动系统中,采用CANopen通讯协议进行信息传输,保证了通讯功能的可靠性; 2. 在电机转速测量中,提出了一种高性能的自适应转速测量算法,与常用的算法相比,提出的算法可以在提高转速测量的准确性的同时,提高系统的响应时间; 3. 在电流测量中,应用巴特沃斯滤波器对电流信号进行滤波,以消除电流采样中的干扰,同时使用Smith预估器消除系统延时产生的影响; 4. 在电机控制算法的研究上,引进了参数模糊自整定PI控制器,该方法实现了高品质的动态和静态性能; 5. 将S/T曲线速度规划的思想引入全数字伺服驱动系统中,通过提高速度的平滑性,特别是高速启、制动状态,来提高伺服系统的整体控制性能。针对DSP芯片定点运算的限制,本文提出了一种余码补偿方案。 本论文理论与实际相结合,以自主研发的服务机器人为平台,对提出的方法进行了实验检验,实验的结果表明本文设计的软、硬件结构合理,控制精度高,响应快,可以满足生产使用的需求。