1,720,965 research outputs found
卢旺达植被和湿地监测
No full text准确地认识和预测植被动态变化对于最大限度地解决发展中国家粮食短缺问题至关重要。植被的动态变化趋势与可持续发展紧密相连，例如可以通过观测植被动态变化趋势来制定相应的政策，便于野生动物保护区和栖息地管理。因气候变化、不合理的土地利用加剧了土地的退化，其评估研究是近年来的研究热点。关于植被和土地资源退化的评估研究可以为政府决策提供依据，为全国生态环境保护工作做出针对性的调整，可以大大提高政府管理部门的工作效率。本研究主要是在全球气候变化背景下，对 1990~2015 年卢旺达最大的湿地—Akagera 湿地资源进行分析并对本国的植被退化的状况进行评估。研究内容的第一部分是监测卢旺达 Akagera 湿地并制图，具体方法和结果参见本文第三章， 采用的数据有 Landsat TM，ETM +和 OLI 卫星影像，和 SRTM 数字高程模型（30m 分辨率）。湿地位于卢旺达 -坦桑尼亚边界，沿 Akagera 河由北向南延伸，总面积约为 100,229.76 公顷。水体占到湿地总面积的 30％，河马草和莎草面积分别占 29.8％和29％，还有小部分洪泛平原和沼泽的森林。虽然近些年湿地面积趋于稳定，但由于物种入侵给湿地生态系统带来了很大的不稳定性。通过分析近年来的影像数据，结果表明 Mihindi 湖，Ihema 湖，Hago 湖和Kivumba 湖面积减少，而 Rwanyakizinga 湖面积略微增加。研究内容的第二部分，文章根据 NDVI 和网格气象数据调查了植被的时空特征和植被绿度与降水之间的相互关系，具体方法和结果参见本文第四章。在这项研究中，利用 AVHRR 和 MODIS NDVI 数据集，并结合降雨趋势，对卢旺达植被 1990~2014 年的第一个生长季的时空动态变化进行评估。基于回归分析和赫斯特指数方法，利用 NDVI 和网格气象数据，研究了植被绿度和降水时空分布特征的相互关系。通过研究发现，植被覆盖总体呈上升趋势，年最大变化率为 0.043。在整个研究期间，全国 81.3％的植被有所改善，另外中轻微度退化占到7.5％，大幅度恶化占到 6.6％，其中 Kigali 市和东部省的退化现象严重。对植被类型变化的分析表明，五种植被受到严重威胁：“马赛克草原/森林或灌丛”严重退化，其次是稀疏的植被、草地或木本植被，人工植被和洪泛区阔叶林。通过计算 Hurst 指数，发现指数变化趋势与植被生长态势相一致，可持续的植被面积为 40.16％，不可持续面积为1.67％，不可预测面积为 58.17％。这项研究能够为政府和地方管理部门提供了有关生态保护的信息，为全国环境保护和可持续发展做出有针对性的意见
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
- …
