1,720,965 research outputs found
Synthesis and characterization of the 2-(-(2-(-2-hydroxy-3-methoxybenzylideneamino)propylimino)methyl)-6-methoxyphenol dimanganese(III) complex containing μ(O,O’)-nitrito-aqua ligands
No full textSingle crystal of new nitrito bridged Mn(III) dinuclear compound {[Mn(L)(H2O)](μ-NO2)[Mn(L)(H2O)]}.(ClO4) has been synthesized in the absence of nitrite source. The compound was characterized by elemental analysis, IR spectroscopy and single crystal X‑ray diffraction. The compound crystallizes in the triclinic system in the space group P‑1 with a = 12.4175(3)Å, b = 13.6360(4) Å, c = 12.8207(5) Å, α = 74.876(3)°, β = 89.064(2)°, γ = 85.361(2)°, V = 2159.39(11) Å3, Z = 9, Dc = 1.489 Mg m-3. Each of the two ligand molecules encapsulates one Mn(III) ion in tetradentate fashion through two phenolate oxygen atoms and two azomethine nitrogen atoms. The two methoxy oxygen atoms of each ligand molecule remain uncoordinated. In the structure, each manganese(III) ion is situated in a N2O4 inner. The environment around each Mn(III) cation is best described as a distorted square pyramidal geometry, in which the equatorial plane is occupied by the atoms from the ligand molecule and the axial positions are occupied by one oxygen atom of a coordinated water molecule and one nitrito oxygen atom. The two Mn(III) ions are bridged though one μ1,3-nitrito group. Numerous intermolecular hydrogen bonds, established between water molecules as donors and phenoxo or methoxy oxygen atoms as acceptors, connect the dinuclear units into three-dimensional network
Tetranuclear copper(II) complex of 2-hydroxy-N,N '-bis[1-(2-hydroxyphenl)ethylidene]propane-1,3-diamine
No full textThe title molecular structure, namely, (μ3-acetato)(μ2-acetato)bis(μ3-1,3-bis{[1-(2-oxidophenyl)ethylidene]amino}propan-2-olato)tetracopper(II) monohydrate, [Cu4(C19H19N2O3)2(CH3CO2)2]·H2O, corresponds to a non-symmetric tetranuclear copper complex. The complex exhibits one ligand molecule that connects two copper CuII metal centres via its ethanolato oxygen anion acting in a μ2-mode and one ligand molecule that connects three copper CuII metal centres via its ethanolato oxygen anion acting in a μ3-mode. One bridging acetate group acting in an η1:η1-μ2-mode connects two copper(II) ions while another bridging acetate group connects three copper(II) ions in an η1:-η2-μ3-mode. A chair-like Cu3O3 structure is generated in which the two CuO4N units are connected by one μ2-O ethanolate oxygen atom. These two units are connected respectively to the CuO3N unit via one μ3-O ethanolate oxygen atom and one μ2-O atom from an acetate group. The μ3-O atom also connects one of the CuO4N units and the CuO3N unit to another CuO3N unit, which is out of the chair-like structure. Each of the two pentacoordinated CuII cations has a distorted NO4 square-pyramidal environment. The geometry of each of the two CuNO3 units is best described as a slightly square-planar environment. A series of intramolecular O—H⋯O hydrogen bonds is observed. In the crystal, the units are connected by intermolecular C—H⋯O and O—H⋯O hydrogen bonds, thus forming sheets parallel to the ac plan
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
Climate change and human migration in Senegal : an approach in terms of social-ecological system vulnerability
No full textLe changement climatique et les migrations humaines constituent deux problématiques majeures de notre époque. Et, partant du constat d’une connaissance fragmentée entre maximalistes et minimalistes, qui s’est traduite par une capacité limitée de la recherche scientifique à prendre en compte les interactions complexes entre le climat et les migrations humaines, cette thèse propose, à travers une approche renouvelée (celle de la vulnérabilité du système socio-écologique), une meilleure compréhension et explication des relations climat- migrations. Elle cherche à répondre à deux objectifs. D’une part, produire des connaissances nouvelles en nous appropriant de façon sélective et ordonnée les apports empiriques produits par les approches précédentes. Et, d’autre part, par une analyse instrumentée des interactions mises en évidence, générer des informations chiffrées pertinentes permettant un ciblage plus efficace des politiques. Cette thèse insiste en premier lieu sur une certaine difficulté à mettre en évidence une relation robuste entre changement climatique et migrations à l’échelle Sahélienne. Contrairement aux idées reçues sur l’image type du « migrant/réfugié climatique » sahélien véhiculée par les médias et reprise, sans un recul critique, dans la littérature grise et certaines études scientifiques, la région, souvent vue et analysée comme une entité relativement homogène, présente de fortes hétérogénéités spatiales physico-climatiques, outre celles socio-économiques. Et, ces dernières ne permettent pas une compréhension des migrations, une des expressions des transformations sociétales. Il convient de repenser la problématique sur des échelles plus homogènes (Sénégal des zones agro-écologiques et régions administratives)Nos résultats montrent un effet climatique accélérateur/amplificateur des migrations interrégionales sous-jacent aux conditions de vie des populations. Généralement, le climat ne suffit pas, à lui seul, à « produire » des migrations. Il transite par les variables socio-économiques (vulnérabilité initiale). Ce qui nous a amené à retenir l’appellation de «migrants éco-climatiques ». Ainsi, les politiques devraient aller à la fois vers : (i) des questions de développement en réduisant des vulnérabilités socio-économiques (pauvreté et inégalités) en agissant sur l’environnement d’action et les acteurs respectivement de manière cohérente et extensive ; mais, également, (ii) des questions d’économie du climat par la réduction de la vulnérabilité physico-climatique à travers des politiques d’atténuation et d’adaptation du milieu et des populations face au changement climatique.Climate change and human migration are two major issues of our time. Starting from the observation of a dichotomous knowledge between maximalists and minimalists, which results in a limited capacity of scientific research to take into account the dynamic and complex interactions between climate and human migrations, this thesis proposes a better understanding and explanation of the climate-migration relations through a renewed and integrative approach (the vulnerability of the socio-ecological system). It aims to fulfill two objectives. On the one hand, to produce new knowledges those take into accounts socio-ecological interactions and feedbacks at different spatial and temporal scales and, on the other hand, to propose a quantified instrumentation of these social-ecological interactions and feedback. This contribution could serve as a starting point for a decision-making tool to evolve towards more targeted and effective policies.This thesis emphasizes a certain difficulty in highlighting a robust relationship between climate change and migration in the Sahel region. This latter, often seen as a relatively homogeneous entity, presents complex socio-economic and physical-climatic spatial heterogeneities that do not allow a stronger understanding of migratory movements which are in change since the 1970s. For this purpose, a reduced complexity model, based both on a partitioning of the study area (Senegal) and a partitioning of data (agro-ecological zones and regions of Senegal), is mobilized as a framework for the analysis of social-ecological migrations in terms of vulnerability induced by climate change. Thus, the innovative heuristic framework built (knowledge model with a sequencing of variables) has made it possible to instrument the climate-migration relationships within Senegal.Our results show an accelerating/amplifying climatic effect of interregional migrations underlying the living conditions of populations. In general, climate alone is not sufficient to "produce" migration. The climatic effects channel through the socio-economic variables (initial vulnerability). Under these results, we retained in fine the name of "eco-climatic migrants". Thus, policies relating to eco-climatic migration in this western part of the Sahel should move towards both: (i) development issues by reducing socio-economic vulnerabilities (poverty and inequality) by acting on the environment and the populations consistently and extensively respectively; and (ii) climate economics issues by reducing the physical-climatic vulnerability through appropriate mitigating and adapting policies to face climate change
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
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