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2.
成教GIS专业人才培养方案的优化设计   总被引:2,自引:0,他引:2  
围绕如何依据成人高等教育的特点办地理信息系统(GIS)专业的建设问题,分析了成教地理信息系统专业的人才培养目标及意义,提出了人才培养过程优化的方案。重点对成教地理信息系统专业的课程体系进行了设计,为成教地理信息系统专业的人才培养提供了实践经验,并提出了一些有借鉴意义的培养方案。  相似文献   
3.
The Maldives was severely hit by massive coral bleaching and subsequent mortality in 1998. The results of reef monitoring in the following years have supported contrasting views about their recovery potential, partly because of the scarcity of information on the situation before 1998. Quantitative data on coral assemblages collected in 1993 in the Rasfari region (North Malé Atoll) may provide a base-line for the evaluation of the present status of the Maldivian reefs. Five years before the 1998 mortality, most coral communities appeared to be similar, in terms of both coral cover and growth-form composition, to those described in 1958 and 1964, notwithstanding increased human pressure and local events such as minor bleaching episodes in 1987 and crown-of-thorns starfish (COTS) attacks in 1989. Three lessons can be learnt from these results to help to understand the present situation, some ten years after the 1998 mass mortality. First, Maldivian reefs proved in the past to be capable of maintaining flourishing coral life despite various disturbances. Second, four years had been sufficient for complete reef recovery after a (minor) bleaching event. Third, recovery after both COTS attack and bleaching follows a predictable path suggesting that the presence of a three-dimensional community structure, which should reduce post settlement mortality of coral recruits, is essential for rapid coral recovery. As coral recruitment remains high and large tabular Acropora colonies are now reappearing, it is expected that Maldivian reefs should return to their original condition within the next few years.  相似文献   
4.
成人英语学习动机行为调查与教学对策研究   总被引:3,自引:0,他引:3  
动机是激励人们行动的心理动因.英语学习动机是推动英语学习的内部动因,成人英语学习动机是复杂的.了解他们的英语学习动机特点有利于教师改进教学手段和策略,激发与培养其学习的主动性和积极性,发挥其学习潜能,从而提高英语学习的效果.运用定量研究的方法,在年轻干部学员中进行学习动机调查,分析了其学习动机的特点,并提出成人英语教学的对策.  相似文献   
5.
石斑鱼鱼虱病的研究 Ⅴ.盐度对南海鱼虱存活的影响   总被引:1,自引:0,他引:1  
记述了盐度对南海鱼虱CaligusnanhaiensisWu&Pan不同发育期的影响。在盐度为10以上时,南海鱼虱的幼虫和成虫对盐度的变化有较大的忍耐性,盐度在10—40之间对幼虫和成虫存活没有明显的影响,24h的实验表明,存活率均为100%。然而,虫卵对盐度的变化较为敏感,虫卵孵化的最适盐度范围为20—35,超出此范围虫卵孵化受到影响。当盐度为10时,虽然孵化率可达100%,但孵出的幼虫活动能力差,多数附着于卵囊上而不能正常活动,不久即死亡。盐度为40时,卵子几乎不能孵化。在淡水中,虫卵、幼虫和成虫均不能正常生存。  相似文献   
6.
Given the high costs of lactation and the importance of milk for pup growth and survival in pinnipeds, nursing behaviour directed by a lactating female towards another adult is unexpected. Here, details were noted of a nursing interaction that occurred between two Cape fur seal Arctocephalus pusillus pusillus adults. After discussing the event in the light of various hypotheses that have been previously proposed to explain uncharacteristic nursing behaviour in pinnipeds, a mother–son relationship between the interacting pair was considered to be the most likely explanation.  相似文献   
7.
The distribution of adult Trichoptera in light traps was investigated alongside nine streams draining catchments under native forest, pine forest, or pasture near Hamilton, Waikato, New Zealand. The aim of the study was to determine the relationship between abundance, taxonomic richness, and community composition with respect to land use during summer, and to evaluate the use of adult Trichoptera compared with benthic invertebrates as potential bio‐indicators of the effectiveness of land‐management changes. Adult Trichoptera faunas alongside the native streams were dominated by Hydrobiosidae, Conoesucidae, and Helicopsychidae (each >10% of total Trichoptera numbers for at least two of the three sites), whereas Leptoceridae, Oeconescidae, and Hydrobiosidae were relatively abundant alongside at least two of the pine sites. Adult Trichoptera faunas at the pasture sites were strongly dominated by Hydroptilidae which made up 47–85% of numbers caught at all sites. The mean number of individuals and taxa caught in light traps increased from November to January and then declined in February for all land‐use types. Overall, total numbers and taxonomic richness of adult Trichoptera were significantly lower at the pine sites compared to the pasture or native sites. TWINSPAN classification of benthic invertebrates collected in November clearly differentiated sites based on land use for presence/absence and percentage abundance data. A similar pattern was evident for most sites when adult Trichoptera faunas were used for the four sampling dates combined, suggesting that light trapping has potential as a tool for bio‐monitoring.  相似文献   
8.
长江水系野生中华绒螯蟹(以下简称河蟹)蟹种比经过多代人工养殖的池塘群体蟹种具有更好的养殖性能,尚不清楚两种蟹种养成后成蟹的可食率及其营养品质是否存在差异。本研究采用养殖实验和生化分析方法,比较了长江水系野生和养殖蟹种经池塘养成成蟹的可食率、肥满度、常规生化成分、脂肪酸和氨基酸组成。结果显示:(1)在相似的体重条件下,野生群体成蟹的肝胰腺指数极显著高于养殖群体(P0.01),性腺指数显著低于养殖群体(P0.05),两群体间的出肉率、总可食率及肥满度无显著差异(P0.05);(2)两群体成蟹肝胰腺和性腺中的常规营养组成接近,但野生群体雄体肝胰腺和性腺中的碳水化合物含量显著高于养殖群体雄体(P0.05);无论雌体还是雄体,野生群体肌肉中的粗蛋白含量显著低于养殖群体,但野生雄体肌肉中的粗脂肪含量和雌体肌肉中的碳水化合物显著高于后者(P0.05);(3)就野生雌体脂肪酸组成而言,野生群体成蟹肝胰腺、卵巢和肌肉中的C18:1n9含量显著高于养殖群体雌体,但其C20:5n3、C22:6n3、ΣPUFA和ΣHUFA显著低于后者;就雄体而言,野生群体成蟹三种可食组织中的C18:2n6高于养殖群体,但其C20:5n3和C20:4n6低于养殖群体;整体上,肌肉中的HUFA含量显著高于肝胰腺和性腺;(4)就氨基酸组成而言,两群体雌体和雄体性腺中的氨基酸含量接近,均无显著差异,仅精巢中组氨酸和精氨酸含量存在显著差异;无论雌体还是雄体,养殖群体肌肉中的主要氨基酸和总氨基酸含量略高于野生群体,仅异亮氨酸和赖氨酸含量差异显著;此外,野生群体雄蟹肌肉中的亮氨酸、天冬氨酸、丝氨酸和组氨酸含量也显著高于养殖群体。综上,野生群体和养殖群体蟹种养成后成蟹的性腺指数和肝胰腺指数存在显著差异,但是两者总可食率和肥满度接近,整体上两群体脂肪酸组成存在较大差异,但是氨基酸组成较为接近。  相似文献   
9.
Abstract

This research examines the effectiveness of problem-based learning (PBL) in an online geographic information systems (GIS) course for adult learners. Adults expect to take greater control of their learning and tend to be self-directed. Students are encouraged to take an active role as problem-solvers in PBL courses. The effectiveness of PBL in face-to-face courses has been shown. Effectiveness in online courses is demonstrated in this study. The performance and experiences of students and instructor in two online courses are compared. The results show that PBL can be more engaging than traditional methods, making PBL-GIS a good choice for an online adult audience.  相似文献   
10.
This is an updated study on the biogeographic distribution of the populations of the genusArtemia (Branchiopoda, Anostraca) in Spain, with special focus on populations inhabiting salt lagoons and inland salterns. The populations recorded (40) belong to the bisexual speciesA. tunisiana and to the asexual groupA. parthenogenetica (diploid and tetraploid strains). They usually appear in three different hypersaline ecosystems: solar salterns and lagoons filled with sea water, solar salterns and lagoons containing brines of diluted mineral salts, and lagoons filled with athalassic (endorheic) brines. The brines in salinas are chemically characterized by high Cl concentrations, especially in inland salinas, whose brine sources are geologically associated with evaporitic formations developed in the Triassic and Lower Liassic of eastern Spain. Brines in athalassic lagoons, geologically associated with Mesozoic and Cenozoic periods, show higher levels of sulfate (up to 40–50%) as well as Mg2+. From a geographical point of view, bisexual and diploid asexual populations are mainly found in coastal and inland salinas or lagoons below 40° N, while asexual tetraploid populations are found in inland salinas and athalassic lagoons above that latitude. These populations have been biologically characterized by the morphology of their adults through multivariate analysis.  相似文献   
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