1,720,981 research outputs found
Modélisation des hétérogénéités de la réserve utile et du développement des cultures au sein d'un sous-bassin versant en Midi-Pyrénées
Full text linkUn défi de la modélisation des cultures est de comprendre et de reproduire les hétérogénéités de développement de la végétation à l'échelle du pédon afin de prédire le rendement. Le but de ce travail est de proposer une méthode de spatialisation des modèles de culture par la spatialisation des données d'entrée, notamment de la réserve utile, pour reproduire les hétérogénéités observées au sein d'un petit sous-bassin versant. Ce travail a été mené en 3 étapes : (1) calage du modèle STICS au contexte local (2) spatialisation des entrées du modèle par une méthode dérivée desapproches SCORPAN et (3) évaluation des simulations spatialisées avec STICS. Préalablement à la spatialisation des données d'entrée du modèle STICS, il était nécessaire d'identifier quels étaient les déterminants des hétérogénéités de végétation observéesau sein du sous-bassin versant expérimental étudié. Pour cela un travail préliminaire a conduit à délimiter les situations pouvant être reproduites par le modèle et les variables pouvant être spatialisées ainsi que de définir une stratégie optimale pour spatialiser les entrées. Sur cette base, une méthodologie de travail a pu être définie pour évaluer et paramétrer le modèle sans spatialisation (approche locale) dans un contexte de sols ayant des propriétés vertiques. Cette particularité des sols locaux nécessite d'établir un nouveau domaine de validité du modèle, compte tenu des hypothèses indispensables (processus considérés comme négligeables) pour simuler dans ce contexte. Par ailleurs, le protocole utilisé pour déterminer la réserve utile a nécessité d'établir la manière dont l'incertitude de la mesure se propageait dans le modèle. Ainsi, grâce à ce travail de spatialisation statistique des mesures, le modèle STICS a pu être utilisé sur des mailles de 8 x 8 m pour simuler le développement de végétation sur tout le sous-bassin versant étudié.One of the challenges in crop modelling is to understand and be able to reproduce heterogeneities in crop development at intra-plot scale in order to better predict the yield. The aim of this work was to suggest a method for spatializing the input data of crop models, in particular the water stock accessible to plants, in order to reproduce the differences in crop development within a subwatershed. This work was carried out in 3 main steps: (1) adaptationof the STICS crop model to the local context, (2) spatialization of the inputs by the spatial correlation method (SCORPAN-like method) and (3) evaluation of the simulated spatialization with STICS model. Prior to spatialization step, it was necessary to identify the determinants of vegetation heterogeneities observed within the experimental subwatershed. A preliminary study led to delimit the situations that could be reproduced by the model and to identify variables that could be spatialized as well as to define an optimal strategy to spatialize the inputs. Based on this, a methodological work was established to evaluate and parameterize the model without spatialization (local approach) in a context of soils with vertisolic properties. Particularity of local soils properties underlined the need to define a new domain of model validity. Moreover, the protocol used to measure water holding capacity, implied a needful and important step that was to determine the propagation of measurement uncertainty in the model. Finally, thanks to statistical spatialization of measurements, STICS model was used on 8 x 8 m meshes to simulate vegetation development on the whole studied subwatershed
Crop heterogeneity and water holding capacity modelling within a sub-watershed in Midi-Pyrénées
No full textUn défi de la modélisation des cultures est de comprendre et de reproduire les hétérogénéités de développement de la végétation à l'échelle du pédon afin de prédire le rendement. Le but de ce travail est de proposer une méthode de spatialisation des modèles de culture par la spatialisation des données d'entrée, notamment de la réserve utile, pour reproduire les hétérogénéités observées au sein d'un petit sous-bassin versant. Ce travail a été mené en 3 étapes : (1) calage du modèle STICS au contexte local (2) spatialisation des entrées du modèle par une méthode dérivée desapproches SCORPAN et (3) évaluation des simulations spatialisées avec STICS. Préalablement à la spatialisation des données d'entrée du modèle STICS, il était nécessaire d'identifier quels étaient les déterminants des hétérogénéités de végétation observéesau sein du sous-bassin versant expérimental étudié. Pour cela un travail préliminaire a conduit à délimiter les situations pouvant être reproduites par le modèle et les variables pouvant être spatialisées ainsi que de définir une stratégie optimale pour spatialiser les entrées. Sur cette base, une méthodologie de travail a pu être définie pour évaluer et paramétrer le modèle sans spatialisation (approche locale) dans un contexte de sols ayant des propriétés vertiques. Cette particularité des sols locaux nécessite d'établir un nouveau domaine de validité du modèle, compte tenu des hypothèses indispensables (processus considérés comme négligeables) pour simuler dans ce contexte. Par ailleurs, le protocole utilisé pour déterminer la réserve utile a nécessité d'établir la manière dont l'incertitude de la mesure se propageait dans le modèle. Ainsi, grâce à ce travail de spatialisation statistique des mesures, le modèle STICS a pu être utilisé sur des mailles de 8 x 8 m pour simuler le développement de végétation sur tout le sous-bassin versant étudié.One of the challenges in crop modelling is to understand and be able to reproduce heterogeneities in crop development at intra-plot scale in order to better predict the yield. The aim of this work was to suggest a method for spatializing the input data of crop models, in particular the water stock accessible to plants, in order to reproduce the differences in crop development within a subwatershed. This work was carried out in 3 main steps: (1) adaptationof the STICS crop model to the local context, (2) spatialization of the inputs by the spatial correlation method (SCORPAN-like method) and (3) evaluation of the simulated spatialization with STICS model. Prior to spatialization step, it was necessary to identify the determinants of vegetation heterogeneities observed within the experimental subwatershed. A preliminary study led to delimit the situations that could be reproduced by the model and to identify variables that could be spatialized as well as to define an optimal strategy to spatialize the inputs. Based on this, a methodological work was established to evaluate and parameterize the model without spatialization (local approach) in a context of soils with vertisolic properties. Particularity of local soils properties underlined the need to define a new domain of model validity. Moreover, the protocol used to measure water holding capacity, implied a needful and important step that was to determine the propagation of measurement uncertainty in the model. Finally, thanks to statistical spatialization of measurements, STICS model was used on 8 x 8 m meshes to simulate vegetation development on the whole studied subwatershed
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
- …
