17 resultados para Edisto River Wildlife Management Area--Maps
em Chinese Academy of Sciences Institutional Repositories Grid Portal
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P> Widespread hunting throughout Amazonia threatens the persistence of large primates and other vertebrates. Most studies have used models of limited validity and restricted spatial and temporal scales to assess the sustainability. We use human-demographi
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Knowledge management is a critical issue for the next-generation web application, because the next-generation web is becoming a semantic web, a knowledge-intensive network. XML Topic Map (XTM), a new standard, is appearing in this field as one of the structures for the semantic web. It organizes information in a way that can be optimized for navigation. In this paper, a new set of hyper-graph operations on XTM (HyO-XTM) is proposed to manage the distributed knowledge resources.HyO-XTM is based on the XTM hyper-graph model. It is well applied upon XTM to simplify the workload of knowledge management.The application of the XTM hyper-graph operations is demonstrated by the knowledge management system of a consulting firm. HyO-XTM shows the potential to lead the knowledge management to the next-generation web.
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Poyang Lake (Poyang Hu) is located at the junction of the middle and lower reaches of the Yangtze (Changjiang) River, covering an area of 3283 km(2). As one of the few lakes that are still freely connected with the river, it plays an important role in the maintenance of the unique biota of the Yangtze floodplain ecosystem. To promote the conservation of Poyang Lake, an investigation of the macrobenthos in the lake itself and adjoining Yangtze mainstream was conducted in 1997-1999. Altogether 58 benthic taxa, including, 22 annelids, 8 mollusks, 26 arthropods, and 2 miscellaneous animals, were identified from quantitative samples. The benthic fauna shows a high diversity and a marine affinity. The standing crops of benthos in the lake were much higher than those in the river, being 659 individuals/m(2) and 187.3g/m(2) (wet mass) in the main lake, and 549 individuals/m(2) and 116.6 g/m(2) in the lake outlet, but only 129 individuals/m(2) and 0.4g/m(2) in the river. The dominant roup in the lake was Mollusca, comprising 63.4% of the total in density and 99.5% in biomass. An analysis of the functional feeding structure indicated that collector-filterers and scrapers were predominant in the lake, up to 42.2% and 24.7% in density and 70.2% and 29.2% in biomass, respectively, while shredders and collector-gatherers were relatively common in the river. The present study was restricted to the northern outlet and the northeast part of Poyang Lake. A scrutiny is required for the remaining areas.
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横断山区干旱河谷地区的土壤是制约植被恢复的一个关键要素,但干旱条件下土壤质量与动态演变状况并不清楚,本研究以岷江干旱河谷核心地段的土壤为对象,研究了阳坡褐土土壤的物理、化学以及生物学特征在海拔梯度(1800m、2000m、2200m)格局及其时间动态(2005-2007)变化,应用主成分分析综合评价了土壤质量及其时空差异性,明确了土壤质量的变化趋势。主要研究结论如下: 1) 海拔梯度上土壤物理性状的变化,2005 年和2007 年土壤物理性状综合质量随着海拔的升高均得到了优化,即海拔2200 m>海拔2000 m>海拔1800 m。 2) 海拔梯度上土壤化学性质的变化,土壤化学综合性质2005 年随海拔升高而趋于变得更优,而2007 年海拔2000 m 最优,海拔1800 m 则最差。 3) 海拔梯度上土壤生物学性质的变化,2005 年土壤生物学性质随海拔升高表现出趋于更好,2007 年海拔2000 m 最优而海拔1800 m 地段最差。 4) 从土壤物理、化学、生物学三方面出发,应用主成分分析,分别分析得出2005 年和2007 年不同海拔高度的土壤质量综合得分。根据综合得分得出土壤质量综合评价的排列顺序为:2005 海拔2200 m>2007 年海拔2000 m>2005 年海拔2000 m>2007 年海拔1800 m>2007 海拔2200 m>2005 年海拔1800 m。2005年土壤综合质量随海拔升高而趋好,2007 年则以海拔2000 m 最优,海拔1800 m和2200 m 差异不大。 5)排除人为干扰后,干旱河谷土壤物理性状在海拔1800 m 略有恢复,海拔2000 m 变化不明显,而海拔2200 m 仍有退化趋势;土壤化学性质在海拔1800 m和2000 m 地段得到恢复,而海拔2200 m 处仍有退化;土壤生物学性质在海拔2000 m 地段呈恢复趋势,而1800 m 和2200 m 仍处于退化状态。综合质量分析表明,与2005 年相比,2007 年海拔1800 m 和2000 m 地段土壤质量趋于变优而海拔2200 m 地段仍有退化迹象。 Soil is a key factor that affect the restoration of vegetation in the Hengduan Mountains dry valley area. But the dynamics and quality of soil is not knowed in dry area. In this study, soil physiochemical and biological characteristics ranging from 1800~2200m above sea level from a typical south-facing slope at the Minjiang River dry valley area had been studied, and characteristics of changes in soil quality along altitudinal gradients and time scales were also discussed. The principal component analysis was used to assess the soil quality. The main results were as follows: 1) Changes in soil physical properties along altitudes. Soil physical properties obtained the optimization along with the elevation in 2005 and 2007. 2) Changes in soil chemical properties. It was summarized that soil chemical properties increased with elevation in 2005, but the soil of 2000 m was the best in 2007. 3) Changes in soil biological characteristics. Soil biological properties increased with elevation in 2005, but the soil of 2000 m was the best and 1800 m was the worst in 2007. 4) Change tendency of soil quality. With the soil physics, chemistry and biology characteristics, we analysised the change tendency of soil quality in altitudes. The result indicated that soil quality increased with altituded in 2005, and soil quality of 2000 m was the best in 2007. 5) In brief, the soil quality is by physics, chemistry as well as the biology synthesizes the influence the final outcome. And the soil quality's change was manifested by soil physics, chemistry and the biology characteristics. All the results indicated soil quality still degenerated at 2200 m in in the dry valley of Minjiang River. And soil quality of 1800 m and 2000 m resumed slight.
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抗生素是广泛应用于人类和动物疾病治疗的药物,近年来在养殖业中抗生素更是常常作为动物催长剂。这些抗生素会通过人畜排泄物、药品的丢弃、污水排放、农业废物堆积等途径进入到环境中。环境中抗生素的残留会导致细菌耐药性的产生、微生态平衡的破坏,以及对生态环境和人类难以预知的影响。抗生素污染是近十年来才在国际上引起注意的新型环境问题,目前研究非常薄弱,要深入认识抗生素的环境影响特征就迫切需要对抗生素在环境中的迁移、归宿等地球化学行为进行针对性的研究。本文研究了贵阳城市污水、南明河及乌江渡水库中氯霉素(CAP)、土霉素(OTC)、四环素(TC)和金霉素(CTC)的环境地球化学特征,包括抗生素的分布、迁移特征及影响因素,并分析了贵阳市动物源性食品中抗生素的残留特征,探讨了环境因素对抗生素稳定性及吸附/解吸的影响,以期了解抗生素在环境中的降解、迁移等环境行为的特征,并据此评价抗生素的环境影响特点,为认识抗生素的污染特点、发展相应的控制、治理措施提供科学依据。主要内容包括: 1. 对环境样品中CAP和TCs的前处理过程和检测方法进行了优化。对水样的前处理采用固相萃取的方法,对土壤和沉积物的前处理采用EDTA-McIlvaine振荡萃取、SAX-HLB净化富集的方法;选择HPLC-UV作为分析的手段,对样品中的4种抗生素进行了检测,各化合物得到了很好的分离,该方法简便、快捷、重现性好。 2. 证实了抗生素在城市污水中的普遍存在。贵阳城市污水中以CAP的污染最为突出,其含量明显高于广州地区的城市污水;污水中四环素类药物(TCs)的含量和大多数欧美国家及地区城市污水中TCs的含量相当。这一结果证明,污水中抗生素的污染非常严重,对地表水环境形成严重的威胁。污水中抗生素的来源包括:人服用抗生素药物以及食用含有抗生素残留的食品之后的排泄物;食品中残留的抗生素随剩余食品的丢弃而进入污水。污水中抗生素的含量都具有明显的季节变化规律,冬春季含量明显高于夏秋季,我们认为这与各季节用水量和疾病特点有关。污水中抗生素的大量存在说明:1)抗生素存在滥用的现象,特别是CAP可能存在严重的违法使用,这一现象应当重视;2)污水中的抗生素会威胁水环境质量,应加强处理和控制技术。 3. 证明了城市河流受到多种来源的抗生素影响,其中城市污水是最重要的源,而且抗生素在河流中呈现一定的持久性。南明河上游河段中抗生素的来源包括郊区城镇污水、养鱼场、制药厂污水排放及地表垃圾。城市污水是抗生素的一大排放源,受其影响,排污口下游的河段受到的抗生素污染尤为严重,此外还有来自下游郊区城镇和农业污水的影响。对南明河中抗生素的来源及行为特点的剖析表明:1)抗生素在南明河的水和沉积物中具有不同的分布特征:河水中以CAP的污染最为严重,各水样中CAP的含量基本都高于TCs;而大部分沉积物中TCs的含量都高于CAP。CAP和TCs在水-沉积物之间的分布特征表明,它们在水环境中的地球化学行为明显受到吸附/解吸特点的影响,CAP的亲水性强,而TCs的亲粒性强。2)虽然在养殖业中已禁止使用CAP,但河水和污水中CAP的大量存在,这一结果揭露了CAP仍然存在大量违法使用的事实。3)河水中抗生素含量的季节差异明显,冬春季抗生素的含量高于夏秋季,其原因主要是夏秋季河水流量大,对河水中抗生素的稀释作用强。沉积物中抗生素的含量没有明显的季节变化规律,各季节抗生素的平均含量差异较小。4)受污水影响,各季节排污口下游的南明河水受到的抗生素污染尤为严重,污水口上下游之间的含量差异明显。沉积物在冬季受城市污水的影响大,在排污口下游的抗生素的含量明显高于上游,而春、夏、秋季受污水影响不明显。这可能是因为在春、夏和秋季其它污染源的影响较大,因此污水的影响强度减弱。夏季上游沉积物中CAP的含量甚至高于下游,原因一方面是因为夏季城市污水中抗生素含量低,对南明河的影响减小,另一方面可能因为夏季雨水多、水量大,将上游的地表垃圾以及积累在小河沟中的垃圾冲刷到南明河中,而这些工业及生活垃圾通常是抗生素的一大来源。 抗生素在河流中呈现了一定的持久性,在20 km的范围内水和沉积物显示了明显的污染水平,可能会对水生生态以及流域的环境造成一定的影响。此外,贵阳市南明河两岸的农田通常是用河水进行灌溉的,从而可能使抗生素的污染危及到食物链,对人体的健康有潜在的威胁。 4. 由于食品(如鱼肉、猪肉等)中残留的抗生素是污水中抗生素的重要来源,因此我们研究了养殖业(水产养殖区)中抗生素的环境行为特点,还研究了常见动物源性食品中抗生素的残留特点。对养鱼区的研究表明,养鱼饲料中含有大量的抗生素,是养鱼区水环境中抗生素的来源。由于饲料的颗粒大,且河水流速快,因此饲料中的抗生素不会对水体造成很大的影响,但是在网箱区的沉积物中形成了高含量的残留,除此以外,在乌江渡主航道的河心沉积物中抗生素的含量也相当可观。这说明该区水产养殖的抗生素主要影响沉积物,且相应的污染不是局部的,而会影响到整个养鱼区。从沉积物中抗生素平均含量的季节差异来看,各季TCs的用药量可能不同,秋季的用量可能最大,而其它季节用量相当;CAP在每个季节的用量可能相当。尽管分析的饲料中CAP的含量高于TCs,但在各季节乌江渡水库主航道沉积物中TCs的含量几乎都远高于CAP,这是由于TCs比CAP更易存在于沉积物中。乌江渡水库上下游主航道沉积物中抗生素的含量差异日益减小,说明了乌江渡水库的污染已日益严重。这些抗生素虽然暂时被固定在了沉积物中,活性相对较小,但是在外界条件的影响下,它们的吸附/解吸作用是可以改变的。因此,乌江渡沉积物中高含量的抗生素残留对水生生态环境具有潜在的威胁。 对贵阳市动物源性食品(鱼肉、猪肉和牛奶)中抗生素的残留特征的分析表明,这些食品中普遍残留有高含量的抗生素,被人食用后,其中的抗生素也会被人体摄入,一部分抗生素会随着人的排泄物而进入到污水中,并最终进入环境中;另一部分抗生素会积蓄在人体中,到一定浓度后就会对人体造成伤害。鲩鱼、鲫鱼、鲤鱼、鳙鱼和鲢鱼中CAP、OTC、TC和CTC的平均含量范围分别在57.1~365.5 µg/kg、37.0~60.7µg/kg、34.3~72.4 µg/kg和22.3~68.0 µg/kg之间。秋季的长吻鲍、团头鲂、鲈鱼、长江洄鱼、对虾、黄鳝、泥鳅和猪肉中CAP、OTC、TC和CTC的平均含量分别为88.1 µg/kg、76.8 µg/kg、343.7 µg/kg和34.2 µg/kg;牛奶中的含量分别为4.2 µg/L、1.6 µg/L和2.5 µg/L和22.0 µg/L。 5. 确定了抗生素的稳定性、吸附/解吸作用与各因素的关系,据此可以探讨环境中抗生素的行为特点及机理,并为环境中抗生素的污染防治提供依据。在短时的加热中,TCs发生了部分降解,而CAP却几乎没有发生分解,说明烹饪过程中的加热不能去除食品中的抗生素,这些抗生素则会进入到人体和污水中。当pH在2~8之间时,TCs的性质较稳定;CAP在pH=1~10的范围内性质都比较稳定。地表和地下水体的pH一般为7左右,说明了水环境中TCs受pH的影响小,而CAP几乎不受影响。在6个月的时间内,TCs在3种介质中都发生了不同程度的降解,但仍有大部分残留;CAP几乎没有发生明显的降解,这说明CAP和TCs的污染具有一定的持久性。TCs的吸附/解吸受颗粒物粒径的影响大,粒径越小,吸附越强;CAP不受影响。这证明了在环境中CAP更易以水溶态的形式存在,而TCs更易吸附在沉积物中。颗粒物中CaCO3含量越高,TC和CTC的吸附越强,证明CaCO3可以用来增强TC、CTC的吸附,这为环境中抗生素的治理提供了一条思路。
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Schizopygopsis younghusbandi younghusbandi is an endemic species whose distribution is restricted to the middle reaches of the Yarlung Zangbo River, being one of the most important commercial fishes in this area. Age and growth of 606 specimens captured between October 2002 and April 2005 were studied. The range in standard length (L) was 65.7-387.3 mm and total weight (W) was 3.3-772.0 g. The relationship between L and W was W=0.000909L(2.2493) for males and W=0.000259L(2.4781) for females. Age, determined from anal scales and lapillus otoliths, ranged from 3 to 18 years. The parameters of von Bertalanffy growth functions, estimated by back-calculated length, were L-infinity = 442.7mm L, k=0.0738 year(-1) and t(0)=-1.4 year for males, and L-infinity = 471.4mm L, k=0.0789 year(-1) and t(0)=0.2 year for females. Males and females exhibited statistically significant differences in growth. chi(2)-test indicated that von Bertalanffy growth functions could well describe the growth of S. y. younghusbandi. The longevities were 39.2 and 38.2 years for males and females, respectively. Growth inflexion points were 10.2 and 12.0 years for males and females, respectively, but 84.8% of the captures were at the smaller ages. So conservation and management schemes for this population should be considered urgently. In addition, we found that populations from the upstream of the Lhasa River, the downstream of the Lhasa River and the middle reaches of the Yarlung Zangbo River showed statistically significant differences in growth patterns.
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Based on a long-term ecological monitoring, the present study chose the most dominant benthic macroinvertebrate (Baetis spp.) as target organisms in Xiangxi River, built the habitat suitability models (HSMs) for water depth, current velocity and substrate, respectively, which is the first aquatic organisms model for habitat suitability in the Chinese Mainland with a long-term consecutive in situ measurement. In order to protect the biointegrity and function of the river ecosystem, the theory system of instream environmental flow should be categorized into three hierarchies, namely minimum required instream flow (hydrological level), minimum instream environmental flow (biospecies level), and optimum instream environmental flow (ecosystem level). These three hierarchies of instream environmental flow models were then constructed with the hydrological and weighted usable area (WUA) method. The results show that the minimum required instream flow of Xiangxi River calculated by the Tennant method (10% of the mean annual flow) was 0.615 m(3) s(-1); the minimum instream environmental flow accounted for 19.22% of the mean annual flow (namely 1.182 m(3) s(-1)), which was the damaged river channel. ow in the dry season; and 42.91% of the mean annual flow (namely 2.639 m(3) s(-1)) should be viewed as the optimum instream environmental flow in order to protect the health of the river ecosystem, maintain the instream biodiversity, and reduce the impact of small hydropower stations nearby the Xiangxi River. We recommend that the hydrological and biological methods can help establish better instream environmental. ow models and design best management practices for use in the small hydropower station project. (C) 2008 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.
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Quantitative studies on the evolution and dynamics of the deepwater area of Pearl River Mouth basin (PRMB) were carried out based on the latest geological and seismic data. The study area is generally in an extensional state during the Cenozoic. The major extension happened in the earlier syn-rift stages before 23 Ma and the extension after 23 Ma is negligible. Two rapid subsidence periods, 32-23 Ma and 5.3-2.6 Ma, are identified, which are related to the abrupt heat decay during margin breakup and the collision between the Philippine Sea plate and the Eurasian plate, respectively. The strongest crustal thinning in the Baiyun (sic) sag may trigger the syn-rift volcanism along the weak faulted belt around the sag. The Cenozoic tectonic evolution of the study area could be divided into five stages: rifting (similar to 50-40 Ma), rift-drift transition (similar to 40-32 Ma), early post-breakup (similar to 32-23 Ma), thermal subsidence (similar to 23-5.3 Ma) and neotectonic movement (similar to 5.3-0 Ma).