1,720,956 research outputs found
Water management of canola under tile drainage in the Canadian Prairies
No full textAn effective water management system is necessary to address global food shortages, water scarcity, and increasing climate extremes. Southern Manitoba is a major crop production area with highly productive soils, flat topography, and seasonally high water table. The objectives of this research were to (i) determine the impacts of controlled drainage (CD), free drainage (FD), and no drainage (ND) on canola yield and quality, (ii) simulate water table depth (WTD) under canola production using the DRAINMOD model, (iii) evaluate the potential impacts of climate change on the hydrology and canola yield using the DRAINMOD model and (iv) assess the performance of the standard ET model under limiting conditions and fourteen empirical ET models in the region. The result shows large differences in yield between the years, suggesting that canola yield is significantly influenced by weather variables. In 2019 with normal average temperature and rainfall close to the long-term average, CD plots consistently yielded higher yields than FD and ND, with a significant difference with FD. As rainfall decreased and temperature increased in the following years, the impact of drainage, especially CD, becomes diminished, with no significant differences between the treatments. Also, the prevailing weather may have masked the oil quality parameters and nutrient dynamics across the soil profile, as there were no significant differences between the treatments. The WTD collected from the PESAI (Prairies East Sustainable Agriculture Initiative) site in Arborg was used to test the ability of the DRAINMOD model to predict WTD using the 2019 and 2020 canola growing seasons. Statistical analysis and graphical plots showed close agreement between the measured and simulated WTD. Economic analysis using the simulation results suggests that the 10 m drain spacing maximized the return on investment. The parameterized DRAINMOD model was thereafter run with downscaled climate model projections from CANESM2 for historical (1981-2010), midcentury (2041-2070), and late-century (2071-2100) periods under three representative concentration pathways (RCP2.6, RCP4.5, and RCP 8.5). Results showed an overall decrease in average relative canola yield under FD and CD in the future. The ET (evapotranspiration) is an essential input to hydrologic models. However, the weather variables required to compute the recommended ET model (FAO PM) equation are not readily available. The results showed that the FAO-PM model decreased with increased missing data, yielding average to poor results. The best performing models were Valiantzas-1, Valiantzas-3, Irmak, Valiantzas-2, and Priestly-Taylor models. New empirical coefficients were also developed to improve selected empirical ET models. Overall, this research is important for developing optimal drainage design variables for increased crop yield.UMGF (University of Manitoba graduate award)
GETS (Graduate Enhancement of Tri-Council Stipends) award, Mitacs, the Canadian Agricultural Partnerships Program, Manitoba Agriculture and Resource Development, the Manitoba Crop Alliance, Barley and Canola growers association, and Grant A. Harris Fellowship.October 202
MODELING CLIMATE AND LAND-USE CHANGE IMPACTS ON STREAMFLOW AND SEDIMENT YIELD OF AN AGRICULTURAL WATERSHED USING SWAT
Get PDFQuantifying the hydrological response due to changes in climate and land-use is imperative for the proper management of water resources within a watershed. The impact of climate and land-use changes on the hydrology of the Upper Ebonyi river (UER) watershed, South East Nigeria, was studied using the Soil and Water Assessment Tool (SWAT) hydrological model. A climatological time series analysis from 1985-2014 using non-parametric test showed significant negative trends in precipitation and relative humidity trend while minimum and maximum temperature, solar radiation and wind speed showed significant positive trends. Future hypothetical land-use change scenarios representing urbanization and conversion of forest to agricultural land were combined with future downscaled climate model (CSIRO-Mk3-6-0) and simulated in SWAT model. Scenario 1 represents urbanization and climate data of 2020-2030; Scenario 2 represents urbanization and climate data of 2040-2050; Scenario 3 represents conversion of forest to agricultural land and climate data of 2020-2030 and Scenario 4 represents conversion of forest to agricultural land and climate data of 2040-2050 while the Baseline Scenario is the present land-use and climate data of 2005-2014. Relative to the Baseline (2005-2014), the results showed a decrease in streamflow by 10.29%, 26.20%, 11.80% and 26.72% for Scenarios 1, 2, 3, and 4 respectively, while sediment yield decreased by 8.2%, 19.4%, 11.1% and 9.1% for Scenarios 1, 2, 3, and 4 respectively. The results suggest development of adaptation strategies to cope with the predicted hydrological conditions under future climate and land-use change in the watershed
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
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