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Evaluating the role of bush fires on the composition, structure, phenology, and resistance of tapia (Uapaca bojeri) woodland vegetation of Ibity massive, New Protected Area, for its sustainable management
No full textAujourd'hui la perte et la transformation des habitats sont les principales menaces qui causent la diminution de la diversité biologique. A Madagascar, 90% des espèces végétales sont endémiques de l’île et la plupart des formations végétales sont actuellement fortement dégradées ou remplacées par des formations secondaires résultant des activités humaines. Le bois de tapia, dominé par l’espèce endémique de Madagascar Uapaca bojeri, est une formation végétale sclérophylle limitée aux Hautes Terres de l’île. Cette formation, adaptée et résistante au régime de feu naturel de la région, est aujourd'hui fragmentée, couvrant une surface équivalente à 132 255 ha au total. Afin d’augmenter la protection du bois de tapia, une nouvelle aire protégée (NAP) a été établie sur le Massif d’Ibity. L’état actuel de la végétation de bois de tapia est le résultat de l’interaction de facteurs comme le type de sol, le climat, les pratiques humaines traditionnelles et le feu. Bien que le feu soit un des phénomènes qui fasse partie de la dynamique de cette végétation, le régime de feu actuel est également une des causes de sa dégradation. L’objectif de cette thèse est donc d’étudier le rôle du feu sur le cycle démographique et certains processus importants pour l’installation et le recrutement. Ainsi, la germination, la phénologie et la résistance des plantules au feu ont été étudiées. Cette recherche montre que le problème actuel du bois de tapia est 1) la réduction de la floraison et de la fructification par les fréquences de feu élevées ; 2) la réduction du pourcentage de germination après l’exposition des graines à de hautes températures, et 3) la mortalité élevée des plantules après le passage d’un feu, en particulier quand la quantité de combustible est élevée. Ainsi l’installation et le recrutement des espèces ligneuses sont limités par le feu, qui a un effet négatif sur la régénération naturelle. La gestion du feu autour de l’aire protégée est ainsi nécessaire pour sa conservationCurrently loss and transformation of habitats are the main threats which cause the decrease of biological diversity. In Madagascar, 90% of plants species are endemic of the island and most of the plant formations types are at present strongly degraded or replaced by secondary formations resulting from human activities. Tapia woodland, dominated by the endemic tree Uapaca bojeri, is a sclerophyllous vegetation type limited in the Malagasy highlands. This vegetation type, adapted and resistant to the natural fire regime, is very fragmented today, covering a surface equivalent to 132 255ha on the island. In order to increase the protection of tapia woodland, a new protected area was established on Ibity massif. The current state of the woody vegetation is the result of the interaction of some factors as soil type, climate, human traditional practices and fire. Although fire is one of the phenomena that determine the dynamics of this vegetation, the current fire regime is also one of the main causes of degradation. The objective of this thesis is to study the role of fire on the demographic cycle and on some main processes for installation and recruitment. Thus, germination, plant phenology and seedlings resistance after burnt were studied. This research shows that the current problem of tapia woodland are 1) the reduction of flowering and fruiting by high fire frequencies; 2) the reduction of germination percent after seed exposure with high temperatures, and 3) high seedlings mortality after burnt, in particular when the quantity of fuel is raised. Installation and recruitment of woody species are limited by fire, which has a negative effect on natural regeneration. Fire management around the protected area is thus necessary for its conservatio
Ny Karazana Aretina Mpahazo Ny Olon-Dehibe Sy Ny Tanora Ao Amin’Ny Tananan’Ny Sahamamy Kaominina Mahavelona Toamasina II
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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
Evaluation quadriennale du dispositif de recherche et d'enseignement en partenariat (DP) " Forêts & Biodiversité à Madagascar " Projet 2017-2020
Get PDFkoamabayili/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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