948 resultados para 24-232
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This publication is a report of the proceedings of the ICSF Pondy Workshop, which focused on the FAO’s Voluntary Guidelines for Securing Sustainable Small-scale Fisheries in the Context of Food Security and Poverty Eradication (SSF Guidelines). The workshop brought together 71 participants from 20 countries representing civil society organizations, governments, FAO, academia and fishworker organizations from both the marine and inland fisheries sectors. This report will be found useful for fishworker organizations, researchers, policymakers, members of civil society and anyone interested in small-scale fisheries, food security and poverty eradication.
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p 24 是H IV 的主要结构蛋白, 在病毒的包装和成熟过程中起重要作用。p 24 蛋白的氨基酸序列在 H IV 各毒株之间高度保守。H IV p 24 抗原的检测在早期诊断、预测病程、胎儿感染确诊和基础研究等方面具有重要 意义。本文主要介绍了H IV p 24 抗原的生物学特性、检测意义, 评述了各种检测方法的主要优缺点和发展趋势。
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Participants consisted of 25 middle and junior level personnel from BOBLME countries. Modules included: Integrated Coastal Management (ICM) concept and principles; ICM development and implementation; indicators of good practice; and action planning.
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This survay has been done from Januray 2000 till May 2002 in Khouzestan costal waters. Four species of grouper were identified from which orange spotted grouper (Epinephelus coioides) was the dominant species. For studing environmental parameters and reproductive biology, age, growth parameters and mortality rate samples were collected by fishing ship. Samples were taken montly in 4 days by fishing traps and trawls. In addition, some samples were obtained from Khozestan fish landing centres. Environmental factors such as PH, 02, salinity, water temperature and depth of traping areas, were measured. To identify species, morphometric characteries of 452 individal fishes were measured. Stomach contents of 394 fish were has survaid, from which stomach of 226 fish, and 168 fish had empty stomachs. Percentage of empty stomachs (cv) in males was more than females. Food items found in 73 percent of stomach were crab (11%), shrimps (8.8%) , squids (3.9%), gastropods (17%) and bivalves (0.4%). Feeding intensity in year classes did not obay logic trends The importance relatively indicator (I.R.I) were 81, 9.9, 4, 1.5 and 0.3 percent for fish, crab, shrimp, squid, gastropod and bivalve respectively. For age determination, sagita otoliths of 450 fish were taken and countable sections were obtained from 425 specimens. Relative frequency distribution of opaque and transparent rings showed that each opaque growth ring generates once a year from November to September. It seemed that generation of opaque rings is affected by temperature and photoperiod changes. Correlation between length and age was calculated using Von Bertalanffy's least square method. Following equasion was obtaind: L(t) : 122.27 (1 e 0.146 (t+0.482)) Growth parameters were determined through by Ford Walford equasion and Response Surface and Shepherd subcommands in Elefan program and L00 and K amounts were have determined. Correlation between length and age of 635 fish was determined by gender . Length and age correlation was calculated by exponential model and between total length and standard length by straghit line model. Correlation between age and weight of sagita was calculated by total length and age. The most Correlation was between sagita weight and fish age (r=0.876). Total mortality rate (z) was estimated by Length Converthed Method , Jones and Vanzaling and Powel Wetherall. Total mortality rate was z=0.39. Natural mortality rate, using Pauly method was calculated M=0.32. Fishing mortality (F) was 0.08. Gonads of 425 fishes were surveid within 18 month, from which 363 were female, 46 were male and 16 were sex reversing individuals .Total length of females varied from 26 to 95.5 centimeters while males length varied from 56.5 to 107 centimeters. Sex reversing individuals had a length of 47.5 centimeters, when two years old and 62.5 centimeters at age of 3 years. From the mentioned 425 fish, 401 individuals were matured, containing 339 females and 62 males, 5.47 females against each male. Montly changes of Gonadosomatic Index (GSI) by total body weight and standard length and total body length showed that this index increases from march to May and maximum increase was in May . This experiment was adapted in spawning season. Potential, relative, and absoulate fecundity was estimated by counting eggs in three samples. Total amount of traped fish using special traps was 16182.18 kg from which Epinephelus coioides provided catching 15353.43 kg of it (91.27 %) and By catch was 141.18 kg (8.24 %). Total average CPUE for whole catch was 123.33 kg/day/vessel. Total amount of catch was estimated 232.04 tons, considering CPUE of total catch and total Khuzestan trap ships effort.
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2007年9~11月和2008年4~5月,对云南省丽江玉龙雪山自然保护区的鸟类资源进行了调查,共记录鸟类184种,结合中国科学院昆明动物研究所鸟类标本室收藏的该地区标本和文献记录的种类,保护区内共记录鸟类330种(另13亚种),隶属47科(另4亚科),18目,占云南省所录鸟类种数848种的38.92%,全国鸟类种数1329种的24.83%。其中国家一级保护物种1种,二级保护物种29种。黑眉长尾山雀Aegithalos iouschistos和大嘴乌鸦Corvus macrorhynchos为保护区内的优势种类。保护区记录的鸟类有留鸟230种和亚种,占所录鸟类种和亚种数的67.05%。区系成分以东洋界物种为主,有182种,占繁殖鸟类总种数的66.42%。亚区级区系分析表明保护区的鸟类以西南山地亚区的种类为主。结合该区鸟类生境分布的特点,提出云南松高山松林、针阔混交林和寒温性暗针叶林的保护是保护工作的重点。
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The performance of porous blocks containing three different reactive magnesia-based cements - namely magnesia alone, magnesium oxide: Portland cement (PC) in 1:1 ratio, cured in ambient conditions, and magnesia alone, cured at elevated carbon dioxide conditions, in hydrochloric acid and magnesium sulfate solution - was investigated. Different aggressive chemical solution conditions were used, to which the samples were exposed for up to 12 months and then tested for strength and microstructure. The performance was also compared with that of standard PC-based blocks. The results showed the significant resistance to chemical attack offered by magnesia, both alone and with PC blend in the porous blocks when cured under ambient carbon dioxide conditions, and confirmed the much poorer performance of blocks made from PC alone. The blocks of solely magnesia cured in elevated carbon dioxide conditions, at 20% concentration, showed slightly lower resistance to acid attack than PC; however, the resistance to sulfate attack was much higher. © 2012 Thomas Telford Ltd.
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沉水植物对重金属的积累净化和受害机理研究主要集中在4个方面:(1)沉水植物对重金属(包括放射性物质)的吸收、积累和净化作用;(2)沉水植物对重金属的抗性强弱和机制;(3)沉水植物用于监测水体的重金属污染:(4)沉水植物的重金属胁迫机制,包括重金属对植物形态和显微结构的损伤,对植物抗氧化酶系统的影响,对植物的叶绿素、蛋白质以及光合与呼吸作用等生理生化指标的影响,植物对重金属的吸附和转运动力学,以及Zn对Cd毒害的拮抗等。
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以1981~2004年间捕获的中华鲟(AcipensersinensisGray)亲鲟样本为研究材料,研究葛洲坝截流24年来中华鲟繁殖季节中坝下30km范围内产卵群体结构的变化情况。测定与统计结果显示,中华鲟雌雄性比由1981~1983年的1.10∶1降低到1987~1989年的0.63∶1,而后上升到2003~2004年的5.86∶1。雌鲟平均体长由1990~1992年的263.1cm增加到1999~2001年的276.7cm,升幅为5.2%(差异极显著);平均体重由1990~1992年的202.4kg
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Polyploid gibel carp, Carassius auratus gibelio, is an excellent model system for evolutionary genetics owing to its specific genetic background and reproductive modes. Comparative karyotype studies were performed in three cultured clones, one artificially manipulated group, and one mated group between two clones. Both the clones A and P had 156 chromosomes in their karyotypes, with 36 metacentric, 54 submetacentric, 36 subtelocentric, 24 acrocentric, and six small chromosomes. The karyotype of clone D contained 162 chromosomes, with 42 metacentric, 54 submetacentric, 36 subtelocentric, 24 acrocentric, and six small chromosomes. All the three clones had six small chromosomes in common. Group G, being originated from the clone D by artificial manipulation, showed supernumerary microchromosomes or chromosomal fragments, in addition to the normal chromosome complement that was identical to the clone D. The offspring from mating between clones D and A had 159 chromosomes. Comparing with the clone A, the DA offspring showed three extra metacentric chromosomes. In addition, variable RAPD fingerprint patterns and unusual SCAR marker inheritance were, respectively, detected among individuals of artificial group G and in the mated DA offspring. Both the chromosome and molecular findings suggest that genome reshuffling might have occurred by manipulation or mating of the clones.
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本文叙述了2.4-二甲基戊二烯基稀土金属有机化合物的合成并通过元素分析,红外光谱、核磁共振谱及质谱的鉴定。测定了Gd(2.4-GH_(11))_3的单晶结构,此外还合成了(2.4-GH_(11)K.TMEDA及K_2C_8H_8·3THF并也测定了它们的晶体结构。在所合成化合物的红外光谱中,没有属于C=C双键的吸收峰,表明分子中配位体以η~5形式的大π键体系与稀土金属离子结合,在Ln(2.4-GH_(11))_2Cl·TMF和Ln(2.4-GH_(11))Cl_2·GH_THF的红外光谱中,于1060波数附近出现一强而宽的吸收峰,即化合物中有四氢呋喃分子络合。化合物的室温NMR谱有四个吸收峰,2.4-二甲基戊二烯配位体可能为η~5平面∪或W构型。化合物的水解'H-NMR谱与质谱都证实水解产物为2.4-二甲基-1.3-戊二烯。它是-2.4二甲基戊二烯阴离子水解所得的唯一产物,它表明化合物中的配位体确为2.4-二甲基戊二烯阴离子。(2.4-GH_(11))_2Cl·TMDA配合物晶体结构是应用低温X-射线衍射技术用Nicolet R_3 M/E型四园衍射仪LT-1低温装置并利用重原子法测定的最小二乘法精修至收敛时的一致性因子R=0.055. Rw=0.057。晶体属单斜晶系P21/n空间群。晶胞参数a=11.322(4)A, b=9.242(3)A, c=15.956(5)A. β=106.70(3)分子中2.4-二甲基戊二烯阴离子呈平面∪构型。钾离子与四甲基乙二胺二啮体结合形成的络合阳离子和2.4-二甲基戊二烯阴离子相间排列形成无限链状结构分子。2.4-二甲基戊二烯阴离子的C-C键长明显分为中间与外端C-C键两组。外端组C-C键双性质较强键长较短。表明C3具有负电荷的共振杂化体贡献较大。分子中K-C键最短的是K-C(1.5)。而不是具有较多负电荷的C3-K键。这可能是由于几何因素造成的。K_2C_8H_8·3THF的晶体结构是采用与前者相同的方法测定的。它属三斜晶系,PT空间群,晶胞参数a=10.263(3)A, b=13.157(4)A, c=9.443A, α=87.51(2)°, β=114.93(2)°, γ=76.81(2)°. V=1111.6A, R=0.051. 晶体中负二价的环辛四烯阴离呈平面构型,具有中心对称性,两侧与两中心对称相关的钾离子连接,相邻的非等效的钾离子间通过两四氢呋喃分子的氧原子相连接,从而形成了无限链状结构的分子。环辛四烯反映了Huckel的4n+2芳香性规则。该结构的特别之处在于四氢呋喃分子的氧原子以桥键形式与两个钾离子同时连接。而这种形式的桥键在其它化合物中似还未发现。Go(2.4-GH_(11))_3的晶体结构亦是采用与前述相同的方法测定的。其晶体为三斜晶系,PT空间群,晶胞参数a=12.541A, b=12.853A, c=8.432A, α=91.44°, β=108.61°, γ=117.97°, V=112.54A~3. 结构测定表明,Gd(2.4-GH_(11))_3分子具有C_3h对称性。三个配位体阴离了的九个带负电荷的碳原子近似以三帽三角棱柱形式与钆离子配位。分子中2.4-二甲基戊二烯阴离子的C-C键长-亦分为而组。外端C-C键较中间C-C键强,键长较短,亦表明C3具有较多的负电荷。2.4-二甲基戊二烯阴离子本身近似呈平面∪构型。C2,C4偏离由C1 C3 C5三碳原子构成的平面0.067A。方向上远离中心钆离子。可能在此以离子性为主的化合物中,钆离子与不带电荷的C2 C4间的相互作用有些排斥性质。与Nd(2.4-GH_(11))_3不同的是,在Gd(2.4-GH_(11))_3分子中,Gd-(C(1,5)键最短,而不是Gd-C(3)键。这可能是由于钆离子的半径较小,化合物的空间位阻效应较大所致。