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971.
论述了高校图书馆绩效评价的定义和意义,指出高校图书馆绩效评价存在的问题,确定绩效评价的方法,并说明高校图书馆的绩效评价重点将会向电子资源的评价倾斜。  相似文献   
972.
  1. Marine protected areas (MPAs) are becoming a widely used tool for the conservation of biodiversity and for fishery management; however, most of these areas are designed without prior knowledge of the basic ecological aspects of the species that they are trying to protect.
  2. This study investigated the movement of two top predators: the Galapagos shark, Carcharhinus galapagensis, and the yellowtail amberjack, Seriola lalandi, in and around the Motu Motiro Hiva Marine Park (MMHMP) using MiniPAT satellite tags to determine the effectiveness of this MPA for the protection of these species.
  3. The Galapagos sharks (n = 4) spent most of their tag deployment periods inside the MMHMP. However, high intraspecific variability was observed in their movement dynamics. Daily individual maximum movements ranged from 17 to 58 km and the maximum distance from Salas y Gómez Island, the only emergent island within the MMHMP, ranged from 31 to 139 km.
  4. The maximum linear distance travelled for a female juvenile Galapagos shark (152 cm total length) was 236 km, which is greater than the maximum distance previously documented for juveniles of this species (<50 km).
  5. For the yellowtail amberjack (n = 1), 91% of the satellite geolocations were within the MMHMP, with a maximum daily distance travelled of 6 km. The maximum distance travelled between points was 111 km and the maximum distance from Salas y Gómez Island was 62 km.
  6. All archival tagged fish spent most of their time at depths of <50 m and never left the epipelagic zone. Daytime versus night-time differences were pronounced in all individuals but showed high interindividual variability.
  7. This study provides a baseline on the movement of these two top predators in the MMHMP and provides valuable insights for the creation of MPAs in the region and elsewhere.
  相似文献   
973.
  1. The white-spotted wedgefish (Rhynchobatus djiddensis) is a Critically Endangered shark-like ray in the family Rhinidae. Throughout its Western Indian Ocean distribution, it is targeted for its valuable meat and fins and is reported to have undergone major population declines. However, there remains a need for species specific time-series data to accurately assess localized population declines.
  2. This study used two independent long-term (37 and 40 years) time-series catch data from competitive shore angling and shark nets to investigate the size composition and catch per unit effort (CPUE) and conduct a risk assessment for the population on the east coast of South Africa.
  3. From 1977 to 2017 the competitive shore fishery captured 7,703 individual R. djiddensis, whilst shark nets in the same region captured 2,856 individuals from 1981 to 2017. Individuals captured in the nets had a sex ratio of 1.8:1 females to males, and were larger than those caught by the anglers. Although the mean annual sizes of net-caught individuals were above the size of reported sexual maturity, there was little evidence to suggest that any individuals captured were reproductively active.
  4. Both the competitive shore fishery and shark net catches exhibited strong seasonal trends with the majority of R. djiddensis catches occurring from October to May peaking in austral summer. Standardized CPUE from the competitive shore fishery declined substantially between 1977 and 2017 and shark net catches exhibited a significant (p < 0.05) fourfold decline in annual nominal CPUE from 1981 to 2017.
  5. Ultimately, a risk assessment showed a 65.1% decline in abundance over a period of three generation lengths, which indicates that the sampled population of R. djiddensis in South Africa should be classified as Endangered according to the IUCN Red List using criterion A2b. The conservation implications of this are discussed.
  相似文献   
974.
  1. Few conservation studies have examined fish communities in entire drainage basins, especially in developing regions such as Southeast Asia, one of the most diverse biomes globally. The aim of this study was to establish conservation projections for the whole of the Irrawaddy River system, based on fish diversity patterns, human impact, and environmental change.
  2. The Irrawaddy River is one of the five largest rivers in Southeast Asia. Although it has very high diversity of fish species and species endemism, our understanding of resident fish status remains poor.
  3. Based on 1,726 field survey and 1,056 database records, 470 fish species and their distribution patterns (i.e. alpha, beta, threatened species, and endemic species diversities) in sub-basins of the Irrawaddy drainage were identified. Canonical correspondence analysis of diversity and environmental patterns indicated that climatic factors had the largest effect on diversity, compatible with the species–energy theory.
  4. Fish conservation priorities of sub-basins were evaluated based on diversity patterns and human impact. The delta and Manipur basin regions were highlighted as areas of focus for future fish diversity conservation, and the importance of connectivity in the Irrawaddy main stem was demonstrated.
  5. The results of this study will be valuable for future management of the Irrawaddy basin and as a reference for other river basins when implementing protection strategies for fish diversity. This study also advocates the need for systematic investigations across entire drainage basins and further detailed studies on the ecological conditions of poorly studied river systems.
  相似文献   
975.
  1. This study evaluated the circle hook use as a tool for shark management in the pelagic longline fishery in the Gulf of Gabès.
  2. The usual J‐hook No. 2 with 10° offset, which has been traditionally used by the fishery, was compared to the 18/0 non‐offset circle hook in an alternating fashion along the main line. In total, 22 experimental longline sets were deployed through the shark fishing seasons of 2016 and 2017 to examine the effects of hook types on the catch composition, the catch rates, the hooking location, and the status at haulback.
  3. The catch composition differed significantly among hook types. Moreover, an overall increase in catch rates for the main species, the sandbar shark Carcharhinus plumbeus, and the shortfin mako shark Isurus oxyrinchus, was observed when using circle hooks.
  4. There was no size‐selective effect of circle hooks for the common species. The circle hooks were not effective at reducing at‐haulback mortality of sandbar shark. Conversely, shortfin mako and smooth‐hound shark Mustelus mustelus showed significantly lower relative mortality at haulback with circle hooks than with J‐hooks. Furthermore, circle hooks were more frequently hooked externally than the J‐hooks for the three shark species.
  5. Results demonstrated that the use of 18/0 non‐offset circle hooks in the pelagic shark longline fishery can reduce mortality at haulback for some species without any benefit for the dominant species, the sandbar shark.
  6. Overall, it is difficult to promote the adoption of the use of circle hooks as a management measure in this specialized fishery. Management measures focusing on fishing effort controls, fishing closures in critical habitats, and size limits could have significant benefits for the conservation of shark species and may help to improve the sustainability of the shark fishery in the Gulf of Gabès.
  相似文献   
976.
ABSTRACT

To maintain the overall quality of fisheries products, functional edible coatings from natural ingredients including fish gelatin (Gf), k-carrageenan (Cr), and extract of pomegranate peels (PPE) were composed. The Gf was extracted from blue tilapia (Oreochromis aureus), microencapsulated with Cr, and then loaded with PPE (at concentrations of 0.5%, 1.0%, 1.5% and 2.0%). The Fourier transform infrared (FTIR) spectra of Gf/Cr composites verified their cross-linkage and functionality; the Gf/Cr microcapsules had a mean particle size of 36.2 µm with good distribution and homogeneity. The coating of Nile tilapia (Oreochromis niloticus) fillets, with constructed solutions from Gf/Cr/PPE, revealed their positive effects on fillet quality attributes; the effectiveness was dependent on the supplemented PPE concentration. The Gf/Cr/PPE solutions could effectively reduce the microbial counts of total aerobics, psychrotrophs, yeast and molds, and enterobacteriaceae groups throughout 30 days of refrigerated storage. Additionally, the analysis of spoilage chemical parameters (total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substances) in coated samples indicated that formulated solutions could hinder the increase of their values during storage. The sensorial evaluation indicated the acceptability and validity of coated samples for up to 30 days of storage. Gf/Cr/PPE coating is recommended for overall quality maintenance of fish fillets and prolongation of storage using safe and healthy biopreservatives.  相似文献   
977.
978.
热风和真空干燥玉米的品质评价与指标筛选   总被引:6,自引:2,他引:4  
为了能对热风和真空干燥后玉米的品质作出合理的评价,对在2种干燥方式和强度下处理的玉米样品物理、生理生化指标进行测定与分析,利用主成分分析法,对干燥后玉米的品质评价指标进行筛选。结果表明,对热风干燥,在温度低于60℃、干燥速率小于4.21%/h时,玉米裂纹率低于35%;当温度高于75℃、干燥速率大于4.65%/h时,玉米电导率急剧升高,丙二醛(MDA)含量、脂肪酸值增加,过氧化物酶(POD)活力下降;玉米初始含水率越高,品质指标受干燥强度的影响越大;而对于真空干燥,当温度低于75℃、干燥速率小于5.56%/h时,玉米裂纹率小于35%,温度高于75℃、干燥速率大于5.56%/h时,电导率和MDA含量、脂肪酸值增加,POD活力下降。主成分分析得到热风干燥玉米的关键评价指标为裂纹率、脂肪酸值、POD活力、MDA含量和电导率;真空干燥玉米的关键评价指标为裂纹率、发芽率、POD活力和电导率,所建立的综合评价模型可反映玉米的干燥品质特性。  相似文献   
979.
1999-2008年中国土地资源经济安全评价   总被引:2,自引:0,他引:2  
采用专家调查法和层次分析法,构建土地资源经济安全综合评价指标体系。研究表明:1999-2008年中国土地资源经济安全呈现上升趋势,2007年和2008年达到“基本安全”水平。从各准则层来看,质量安全和效率安全呈现逐年上升趋势,2008年均达到“安全”水平;数量安全、结构安全和价格安全是制约中国经济增长的主要因素,长期处于“不安全”甚至“高度不安全”状态。从各指标来看,单位播种面积产值、环保投资占GDP的比例等质量安全指标,以及单位面积土地固定资产投资、单位面积土地GDP、复种指数等效率安全指标的评价值显著提高;不利因素是:人均耕地面积分值逐年下降,2008年接近“绝对不安全”;土地开发复垦面积、人均未利用土地面积得分也呈现逐年下降趋势;森林覆盖率偏低;住宅用地、商业用地价格近年来波动过大。  相似文献   
980.
普洱茶发酵阶段色泽的变化及其与品质的关系   总被引:2,自引:1,他引:1  
为阐明普洱茶不同发酵阶段色泽变化及其与普洱茶品质的关系,研究了恒温恒湿与恒温非恒湿条件下,接种外源优势菌(酿酒酵母)与未接种外源优势菌的云南普洱茶在不同发酵阶段的感官品质、汤色的定量分析及茶色素含量的变化。结果表明:明度指数L及明度指数差ΔL与感官指标汤色的评分呈正相关;色品指数a、b及色差值Δa、Δb与汤色感官评分、滋味评分和品质总评分均呈正相关;不同发酵阶段样的ΔL、Δb的值逐渐减小,而Δa的值逐渐增大,这与其茶红素和茶黄素的值逐渐减小和茶褐素的值不断增大是一致的。普洱茶发酵阶段色泽的量化分析可作为普洱茶品质评价的重要指标,在自动化恒温恒湿条件下发酵普洱茶,有利于实现普洱茶清洁化加工和提高普洱茶品质的稳定性。  相似文献   
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