1,720,956 research outputs found
Effect of Future Climate Change on Water Footprint of Major Crops in Southern Tajikistan
No full textIPCC 气候模式表明中亚地区未来将明显变暖，并面临更加频繁的干旱和高温事件。气候变化将对农业、生物多样性、人类健康、生态环境以及整体经济产生深远影响。因此，气候变化变化引起的诸如在极端事件（例如干旱和洪水）加剧了全球和区域中水文、气象和生态等方面的一系列的不确定性。根据脆弱性指数分析显示，作为山地国家的塔吉克斯坦适应气候变化的能力很差，是欧洲和中亚地区中适应气候变化的能力最差的国家之一。塔吉克斯坦人口不足 700 万，是中亚地区最贫穷的国家，国际农业发展基金会（IFAD）的数据显示，一半以上人口仍属贫困，且 80％的贫困人口生活在农村地区。虽然一半以上的人口以农业为生，农业占 GDP 的 20％以上，而且塔吉克斯坦高度依赖粮食进口，极易受到外部大环境的影响。塔吉克斯坦的粮食危机和粮食安全，受到了该国和世界组织的高度重视，都强调农业部门在消除贫困、实现农村发展和保障粮食安全方面的重要地位。因此，在气候变化的影响下，农业和粮食生产直接受到温度、降雨和二氧化碳等气象要素和水、热或土壤等下垫面变化的影响。因此，气候是农业生产力、国家粮食安全和经济可持续发展的主要决定因素之一。定量预测塔吉克斯坦未来气候变化对其农业生产的影响，是科学调整农业政策的重要科学支撑。苏联在乌兹别克斯坦、土库曼斯坦、塔吉克斯坦和吉尔吉斯斯坦建立了棉花产区，如今，棉花依然是重要的经济作物，但地方政府也逐步加大粮食的产量，以减少进口已成为它们的当务之急。棉花种植面积逐步减少，冬小麦面积翻了一番。在塔吉克斯坦，小麦是成为需水量最大的作物，占农业用水总量（蓝水和绿水）的 39％，其次是棉花，占 33％。塔吉克斯坦绿水和蓝水资源的可利用性存在巨大的区域差异，该地区的虚拟水的科学调配是进行地区间水资源科学分配的重要方法之一。 因此，本项聚焦塔吉克斯坦主要农业区（南部哈特隆地区中 Danghara），研究主要通过统计降尺度方法阐明当地温度和降雨的气候变化趋势，量化区域内主要作物水的足迹，估算气候变化对未来不同阶段下主要粮食作物生长期的影响，确定适应气候变化下的最佳播种日期，优化未来主要作物的需水量。本项研究基于 31 年的历史温度和降水数据，使用使用统计降尺度法（SDSM），验证和校准了 CanESM2 全球气候模型（GCM）历史数据，并分析的三种典型浓度路径（RCP）在两个未来时间跨度（2021-2050 年、 2051-2080 年） Danghara 地区可能的未来气候变化趋势。针对棉花、土豆和冬小麦三种主要农作物，计算了历史和未来不同时段下的主要作物的作物需水量，量化了主要农作物的水足迹作，并通过优选最佳播种期（OSD）以减少未来农作物的需水量对于当地/区域水资源配给压力。结果表明:（1）对于全球气候模式的三个预测变量（最大温度、最小温度和降雨），降尺度模型校准和验证取得了较好的结果，其评价参数 R2、 DW 和 RMSE 分别为 0.5 - 0.9、 1.4 - 1.9 和 1.5 - 2.6 之间。对于两个未来时期（2021-2050 年和2051-2080 年），在三种排放情景（RCP 2.6、 4.5 和 8.5）下，最高温度和最低温度均呈上升趋势。在第一阶段（2021-2050 年），三种情景（RCP 2.6、 4.5和 8.5）的年均最高温度升温幅度分别为 0.35°C， 0.40°C 和 0.61°C，年均最低温度分别增长 0.23°C， 0.27°C和 0.39°C；与历史降雨数据相比，未来降雨的增幅达到 8.42％、 7.96％和 10.78％。在第二阶段（2051-2080 年）升温幅度将更大，三种情景（RCP 2.6、 4.5和 8.5）下，年度最高温度将升温 0.51°C， 0.70°C和 1.26°C，年度最低温度分别提高 0.34°C， 0.46°C 和 0.93°；未来降雨增幅将达到 10.89％、 10.77％和 8.92％。（2）未来降水和温度的增加将导致现有生长期的主要农作物水足迹的增加，这主要是由于长期以来其绿水和 2051-2080 年内蓝水减少（棉花除外），其他组分保持相对稳定。在未来三种情景下（RCP 2.6、 4.5 和 8.5），棉花的绿水量在 2021-2050 年将分别增长 4.3％， 7.8％和 7.1％，在 2051-2080 年将分别增长 7.1％， 7.4％和 7.2％。马铃薯的绿水在未来第一阶段将分别增长 5.3％， 6.9％和 7.4％，在未来第二阶段分别增长 9.6％， 10.1％和 7.5％。而冬小麦的绿水增加幅度最大，未来第一阶段，其增加量为 7.5％， 8.7％， 9.2％，在未来第二阶段的增幅为 10.6％， 11％和 9.3％。与绿水不同，蓝水并没有呈现整体上升的趋势。未来第一阶段的马铃薯和未来两个阶段内的冬小麦的灌溉需求将大大减少。但就棉花而言，蓝水组分还是略有增加，在未来第一阶段将分别增加 1.4％， 0.9％和 1.5％，在未来第二阶段将分别增加 1％， 1.2％和 2.3％。（3）将水足迹的变化与气候变化情景综合分析，可以看出，冬小麦和秋马铃薯将在生长期获得更多降雨。另一方面，尽管每年降雨量都在增加，但由于棉花生命周期主要发生在塔吉克斯坦的旱季，棉花灌溉用水在旱季中的需水矛盾同样在增加。由于作物物候对作物需水量和生产力的有着决定性的影响，因此，在生长期有效降雨量将决定着灌溉需求的变化。于是，在未来第一阶段 RCP 4.5 和 RCP 8.5 情景下，有效降雨量的稳定增加将导致冬季小麦的灌溉需求相对降低；在未来第二阶段，除 RCP8.5 之外，所有情景下小麦和马铃薯的灌溉需求都会下降。在两个研究阶段的三个情景下，将提前十天播种定义为最佳播种期，马铃薯和冬小麦的水足迹分别从 1.1％升至 1.4％， 2.9％升至3.4％。尽管最佳播种期显示棉花的水足迹保持稳定增长，但同时灌溉需求或蓝水明显下降。在 2021-2050 年，棉花、马铃薯和小麦的有效降雨量分别由13.3％增长至 14.4％， 10.5％至 12.1％和 9.4％至 11.2％； 2051-2080 年中三个情景下棉花的有效降雨量增长量分别为 13.2 至 15％， 12.4 至 14.9 ％，和 11.3至 12.5％。有效降雨量的稳定增加导致所有作物的灌溉需求量相对降低（除了2051-2080 年期间的 RCP 8.5 下的棉花）。我们的研究结果将有助于灌溉系统新策略的制定，以及在满足环境用水和人类需求的水-食物之间取得平衡。综合的水资源管理政策是确保可持续性发展和公平分配水资源的重要措施。同时，发展耐热物种可能是塔吉克斯坦农业发展的另一个机会，特别是在南部地区。因此，我们建议政府改善农业基础设施并为农民提供培训。此外，出色的选种，滴灌，覆膜和轮作也可以大大增加作物产量。这项研究选择了一个气候观测站模拟未来的气候变化，并基于作物需水量和灌溉用水估算了主要农作物的水足迹，由于气象观测站的数量限制，以及选取 GCM 模式数量的限制，存在未来气候变化趋势分析的不确定性，在未来研究中，可以增加其他相关数据源和气候模式集合， 以减少趋势分析的不确定性；同时由于塔吉克斯坦南部土地利用数据的精度较低，灌溉面积和农作物结构存在一定不确定性，期望在以后的工作中对此进行改进
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
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