1,720,965 research outputs found
Long-Term Impact of Soil and Water Conservation Measures on Soil Erosion in a Tunisian Semi-Arid Watershed
No full textUnderstanding and long-term assessment of the efficacy of soil and water conservation (SWC) techniques is essential for sustainable watershed management. There have been few studies measuring the long-term impact of SWC on soil erosion at the catchment scale due to a lack of historical data. This research aims to measure and analyze the impact of SWC interventions on sediment yield using the Soil and Water Assessment Tool (SWAT) in the Wadi Rmel watershed between 2000 and 2020. The study approach has simultaneously three main aspects: (i) long-term and temporally dynamic, (ii) large-scale landscape distribution, and (iii) empirical evidence of im-pacts induced by terracing measures. Historical data on SWC in 2000, 2005, 2010, 2015, and 2020 were used for running the model. The monthly calibration (2001-2014) using the SUFI2 algorithm was implemented with 22 input parameters and displayed a good model performance, with a Nash-Sutcliffe efficiency (NSE) of 0.61 for daily runoff and a coefficient of determination (R2) of 0.66. A satisfactory result was obtained for the monthly validation process (2015-2020) with NSE value equal to 0.83 and R2 value of 0.85. The result showed the increase in terracing areas led to a cumulative decrease in watershed sediment yield in long-term, i.e., the reduced erosion per one hectare of the expanded terracing area after 10-20 years were about 9-33 times higher than those in the first 5 years. This finding suggests that maximal benefits of SWC should be expected in the long-term, i.e., beyond a decade. Additionally, the study revealed variations in sediment yield contribution among sub-basins, with the southwestern region being the degradation hotspot areas (having erosion exceeding tolerable thresholds) needing prioritization for erosion controls. These find-ings enable stakeholders to plan effective management in semi-arid wheat-based agricultural areas with scarce data
Parameterization of the Effect of Bench Terraces on Runoff and Sediment Yield by Swat Modeling in a Small Semi-arid Watershed in Northern Tunisia
No full textIn Tunisia, soil and water conservation interventions are among the most practicable strategies to prevent and mitigate rainwater losses through surface runoff and consequential erosion of fertile soils. In this study, a small and terraced agricultural catchment (Sbaihia) was used as an experimental site to analyze and parameterize the effects of bench terraces on water and sediment yield using the Soil and Water Assessment Tool. Model calibration and validation was performed, taking advantage from high-quality daily runoff data from 1994 to 2000 and a high-resolution bathymetric survey of the hill lake at the watershed outlet. Soil and Water Assessment Tool indicated that the local terraces, established on approximately 50% of the watershed area, reduced surface runoff by around 19% and sediment yield by around 22%, decelerating the siltation of the hill lake. Targeted model calibration delivered concise parameter set describing bench terrace impacts on runoff (Soil Conservation Service curve number method) and sediment yield (Modified Universal Soil Loss Equation) crucial for outscaling of soil and water conservation impacts and suitable watershed management. © 2016 The Authors. Land Degradation & Development Published by John Wiley & Sons Ltd
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
Toward an operational tool to integrate land degradation neutrality into land use planning: LUP4LDN
No full textLand use planning (LUP) to achieve Land Degradation Neutrality (LDN) needs methods and tools that support the identification of best LUP solutions in terms of transitions from current degradative land use (LU) and land management (LM) practices to better LU and LM options. A crucial need is the identification of context specific sustainable land management (SLM) options. Addressing this need must aim at not only reversing/recovering past degradation (e.g., via restoration or rehabilitation in land degradation hotspots), but also avoiding "new" degradation possibly caused by unsuitable LU and LM. This requires SLM planning based on anticipated impact assessment of the LU-LM transition scenarios set to achieve LDN, which can be achieved through a participatory planning process that integrates interests/needs and knowledge of stakeholders with science-based supportive tools to identify rational, plausible, and socially relevant options. The geoinformatics Land Use Planning for LDN (LUP4LDN) conceptual procedure and tool have been designed for this purpose. Their aim is to support national and subnational planners by (i) mapping geographic patterns of past land degradation (LD) utilizing the LDN indicators adopted by the UNCCD (SDG 15.3.1 indicator) for user-defined regions of interest (RoI); (ii) helping users anticipate future LD by identifying land that is unsustainably managed and that will likely become degraded during the planning period; (iii) partitioning the LD areas into spatial domains of socio-ecological contextual similarity (i.e., contextual similarity units) to which the LU-LM transitional options will be fitted; and (iv) providing an interactive procedure for participatory LU-LM transitional scenario development over selected contextual similarity units and timeframes. LUP4LDN uses the Global Database of the World Overview of Conservation Approaches and Technologies (WOCAT), ICARDA's Geoinformatics Options by Context (GeOC) tool, and ELD (Economics of Land Degradation) indicators to identify context-relevant SLM that are available in the RoI, suggests candidate SLM options, and visualizes related expected levels of impacts on ecosystem services via maps and graphs. The generated maps inform users about trade-offs upon which users can discuss or negotiate transitional pathways. LUP4LDN has been codeveloped with national stakeholders in Tunisia and Burkina Faso. The piloting implementation in the two countries assessed how LUP4LDN fits with existing LUP processes and the benefits achieved by using the tool to support LUP for LDN
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
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