1,720,994 research outputs found
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
Energy saving in indoor farming : study of the effects of photoperiod modifications on agronomic parameters and pre and post harvest physiology of lettuces
No full textFace aux enjeux actuels, les méthodes de production agricole se sont diversifiées, notamment avec le développement de l'agriculture en environnement contrôlé, appelée aussi agriculture indoor. Cette agriculture a une bonne efficience de l'eau mais consomme une grande quantité d'énergie à cause de l'apport de lumière artificielle. L'objectif de cette thèse a été d'étudier l'impact de modifications de photopériode permettant de réduire le temps d'éclairement et donc d'économiser de l'énergie. Les effets de ces modifications ont été étudiés sur les paramètres agronomiques et la physiologie des laitues en pré et post-récolte. Ce travail est une collaboration entre Avignon Université et Futura Gaïa Technologies, une entreprise d'agriculture indoor qui conçoit et commercialise des fermes verticales « clés en main » contenant des systèmes de cultures rotatifs à axe horizontal. Le premier travail a été de caractériser l'impact de la rotation, qui perturbe la perception de la gravité. Cette perturbation se traduit par une diminution de la conductance stomatique, de l'efficience du photosystème II et de la photosynthèse nette, mais n'impacte pas le rendement commercialisable des laitues après 30 jours de culture. Ensuite, les modifications de photopériode ont montré que l'allongement de la période d'obscurité induit une diminution de la photosynthèse nette suite à la perturbation du rythme circadien de l'ouverture stomatique. Les analyses ont ainsi permis de définir les périodes où les plantes utilisaient la lumière de la manière la plus efficiente, ce qui a permis de proposer deux nouvelles modalités de photopériode permettant 12.5% et 25% d'économie des heures d'éclairement et donc d'énergie. Le rendement en masse fraîche des laitues sous la modalité '12.5%' est similaire à celle des laitues témoins grâce à une meilleure hydratation, bien que la masse sèche soit plus faible que celle des laitues témoins. Les rendements en masse fraîche et sèche des laitues sous la modalité ‘25%' sont deux fois plus faibles que ceux des laitues témoins. Les mesures de photosynthèse nette en fonction du temps ont montré que les pertes de rendement en masse sèche sont une conséquence du déphasage entre la photopériode et le rythme circadien de l'ouverture stomatique, ce qui altère le rythme et diminue l'ouverture stomatique. Des expérimentations complémentaires ont permis d'émettre l'hypothèse que les photorécepteurs sensibles à la lumière rouge (660 nm) et impliqués dans le rythme et l'intensité de l'ouverture stomatique pourraient être utilisés pour améliorer l'efficience de la lumière en agriculture en environnement contrôlé. Cette thèse soutient ainsi l'idée de prendre en considération la chronoculture, qui devra être associée aux autres méthodes d'économie d'énergie, pour améliorer la durabilité de l'agriculture indoor.Faced with today's challenges, agricultural production methods have diversified, notably with the development of controlled-environment agriculture, also known as indoor farming. This type of agriculture is highly efficient in terms of water use, but consumes large amounts of energy due to the need for artificial light. The aim of this thesis was to study the impact of photoperiod modifications to reduce lighting time and thus save energy. The effects of these modifications were studied on the agronomic parameters and physiology of pre- and post-harvest lettuces. This work is a collaboration between Avignon University and Futura Gaïa Technologies, an indoor farming company that designs and markets "turnkey" vertical farms containing horizontal axis rotary crop systems. The first task was to characterize the impact of rotation, which disrupts the perception of gravity. This disruption results in a reduction in stomatal conductance, photosystem II efficiency and net photosynthesis, but has no impact on marketable lettuce yield after 30 days of cultivation. Secondly, photoperiod modifications showed that lengthening the dark period led to a reduction in net photosynthesis as a result of disruption of the circadian rhythm of stomatal opening. The analyses thus enabled us to define the periods when the plants used light most efficiently, and to propose two new photoperiod modalities offering 12.5% and 25% savings in light hours and therefore energy. The fresh mass yield of lettuces under the '12.5%' modality is similar to that of control lettuces, thanks to better hydration, although dry mass is lower than that of control lettuces. The fresh and dry mass yields of lettuces under the '25%' modality are half those of control lettuces. Measurements of net photosynthesis as a function of time have shown that dry mass yield losses are a consequence of the phase shift between photoperiod and the circadian rhythm of stomatal opening, which alters the rhythm and reduces stomatal opening. Complementary experiments have led to the hypothesis that photoreceptors sensitive to red light (660 nm) and involved in the rhythm and intensity of stomatal opening could be used to improve light efficiency in controlled-environment agriculture. This thesis thus supports the idea of considering chronoculture, which should be combined with other energy-saving methods, to improve the sustainability of indoor farming
Oxydation et dégradation de l'ascorbate chez la tomate et impact sur la croissance et le métabolisme
No full textAscorbate metabolism and particularly ascorbate redox status are involved in stress tolerance and growth processes of plant cells. The concentration of ascorbate and its redox status are under control of (i) its biosynthetic pathways, (ii) the ascorbate-glutathione cycle allowing recycling of semi-oxidized and oxidized forms of ascorbate and (iii) its degradation rate. These processes are under environmental control. Transgenic lines modified for the activity of monodehydroascorbate reductase (involved in ascorbate-glutathione cycle) and ascorbate oxidase were generated in cherry and large-fruited genotypes of tomato. Physiological and metabolic modifications related to the modification of these enzyme activities were studied. We observed large phenotypic alterations that affected fruit yield under both stress conditions and normal growth conditions. Links between ascorbate recycling and sugar metabolism, photosynthesis and stomatal conductance were also revealed. An imbalance between the oxidizing and reducing activities of these enzymes is the first step leading to ascorbate degradation. We have shown that the degradation rate was very low under light, whereas under darkness the degradation compounds oxalate, threonate and oxalyl-threonate accumulated in tomato leaves. Also, the degradation rate is correlated with MDHAR activity. These results highlight the crucial role of the redox status of the ascorbate / monodehydroascorbate couple in growth processes and yield stability in tomato, and the impact on ascorbate degradation.Contrôle de l'oxydation et de la dégradation du pool de vitamine C chez la tomate et impact sur la qualité du fruit et la tolérance au stress. Le métabolisme de l’ascorbate et plus principalement le statut redox du pool d’ascorbate sont impliqués dans la tolérance au stress et dans les processus primaires de croissance et de développement de la plante. La teneur et le statut redox de l’ascorbate chez les plantes sont régulés par (i) ses voies de biosynthèse, (ii) par le cycle ascorbate-glutathion permettant le recyclage des formes semi-oxydées et oxydées de l’ascorbate et (iii) par sa dégradation, l’ensemble de ces processus étant sous le contrôle de l’environnement. Au cours de ce travail de thèse, des méthodes de transgénèse nous ont permis d’identifier, chez différents génotypes de tomate à petit et gros fruits, les bouleversements physiologiques et métaboliques permettant de compenser des modifications de l’activité des enzymes monodéhydroascorbate réductase (impliqué dans le cycle ascorbate-glutathion) et ascorbate oxydase. Nous avons observé d’importantes modifications phénotypiques altérant le rendement en fruits de la plante sous conditions de culture pouvant générer un stress et également en condition normale de culture. Des liens entre l’activité des enzymes précités avec le métabolisme des sucres, la photosynthèse et la conductance stomatique sont révélés. Le déséquilibre entre les activités oxydantes et réductrices de ces enzymes constitue la première étape vers une dégradation de l’ascorbate. Le taux de dégradation se révèle très faible à la lumière, tandis qu’à l’obscurité une forte accumulation des produits de dégradation l’oxalate, le thréonate ainsi que l’oxalyl-thréonate est observé dans les feuilles de tomate. Enfin, l’activité de l’enzyme MDHAR est corrélée au taux de dégradation à l’obscurité. Les travaux de cette thèse mettent en avant l’importance du statut redox du couple ascorbate / monodéhydroascorbate dans les processus de croissance cellulaire et entre dans la régulation du rendement chez la tomate, et influe la dégradation de l’ascorbate
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
