1,720,952 research outputs found
Assessing maize crop water stress using an aerodynamic temperature approach
Full text linkThe purpose of the study is to assess improvements on irrigation water management by evaluating the applicability of aerodynamic temperature methods for sensible heat flux to estimate crop water stress index. Analysis were performed for maize under water stress conditions. Data were collected at a research farm located in Greeley, CO in 2018. Areas of investigation: Irrigation water management, surface energy balance concepts, remote sensing.2019 Fall.Includes bibliographical references.This study evaluates two methods for determining maize crop water stress index (CWSI) using a surface energy balance coupled with an aerodynamic temperature approach. Data were collected on an irrigated maize field, at a research farm located near Greeley, Colorado, USA, in 2018. The irrigation treatment was subsurface drip. Weather data were measured on-site at 3.3 m above ground level. Remote sensed red (RED) and Near infrared (NIR) surface reflectance data were obtained on-site through radiometry measurements done twice a week. Nadir surface temperature was measured using infrared thermometers kept at 1 m above canopy height. Aerodynamic temperature models developed by Chavez et al. (2005) and Costa-Filho (2019) were used to independently estimate CWSI based on the surface energy balance approach. Independent CWSI from measured surface heat fluxes were used as reference for model performance assessment. Results indicated that estimated CWSI based on Costa-Filho (2019) model had mean bias error (MBE) of -0.01 and root mean square error (RMSE) of 0.08, while model from Chavez et al. (2005) resulted on MBE of -0.24 and RMSE of 0.27. Both models underestimated CWSI values due to negative values of MBE, but Costa-Filho (2019) model improved CWSI estimation by reducing the magnitude of RMSE in 30 % when compared to CWSI estimated using Chavez et al. (2005) aerodynamic model. Therefore, research results indicate that there is evidence that the CWSI approach based on Costa-Filho (2019) model for aerodynamic temperature seems to improve estimation of maize CWSI for semi-arid conditions.National Institute of Food and Agriculture (US) (CAP 2016-68007-25066) and National Institute of Food and Agriculture (CO00688)
066 - Edson Costa Filho
No full textColorado State University - Civil and Environmental Engineering.Includes bibliographical references.Better irrigation water management requires accurate estimates of crop water use. Modeling evapotranspiration (ET) using the surface energy balance approach and remote sensing data has been showing promising results, but the complex nature of heat and momentum transfers among land, plants, and atmosphere has imposed a challenge towards obtaining more accurate crop water consumptive use results. The project aims to improve estimates of crop ET by improving the estimation of sensible heat (H), the most critical component of the surface energy balance, through a combined application of remote sensing data and an aerodynamic temperature approach
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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