1,721,016 research outputs found
Direct and semi-direct aerosol effects on the southern African regional climate during the austral winter season
No full textIncludes abstract.Includes bibliographical references (p. 195-219).The regional climate model RegCM3 is used to investigate the direct and semi-direct aerosol effects on the southern African climate during the austral winter season (June-September). The sensitivity of simulated aerosol-climate effects to different biomass burning inventories, boundary conditions and sea surface temperature (SST) feedbacks is tested to assess the range of uncertainty associated with these parameters
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
Chile Niño/Niña processes across a hierarchy of models
No full textLa région d'upwelling de frontière Est du Pacifique Sud-Est (SEP) est l'une des zones océaniques les plus productives sur le plan biologique à l'échelle mondiale, ce qui lui confère une grande importance pour la sécurité alimentaire et les activités socio-économiques. Ces dernières années, les vagues de chaleur marine ont attiré l'attention de la communauté scientifique en raison de leurs effets délétères, qui devraient être exacerbés par le changement climatique, un problème auquel le SEP est particulièrement vulnérable. Récemment, de nouveaux modes climatiques couplés air-mer ont été identifiés dans tous les principaux systèmes d'upwelling côtière et ont été baptisés Niños côtiers. Au large du Chili central, un tel mode, appelé Chile Niño/Niña, se produit et détermine une part substantielle de la variabilité locale de la température de surface de la mer. Améliorer notre capacité à prévoir de tels événements est un défi important qui a des implications sociétales claires pour les pays proches de la côte ouest de l'Amérique du Sud. Dans cette thèse, nous avons étudié les mécanismes sous-jacents de Chile Niño/Niña et ses changements prévus dans le cadre du changement climatique. Pour ce faire, nous avons utilisé des observations, des produits de réanalyse et un ensemble de modèles d'une grande complexité, allant de modèles conceptuels simples et de modèles basés sur des données, à des modèles climatiques complets. Un modèle régional couplé de complexité intermédiaire a également été développé. Nous constatons que l'oscillation du Pacifique Sud (SPO) et El Niño-Oscillation australe (ENSO) sont des précurseurs de Chile Niño/Niña, tandis que le mode méridien du Pacifique Sud (SPMM) y est étroitement lié. En outre, nous montrons que la variabilité quasi-annuelle de Chile Niño/Niña peut être interprétée comme résultant d'un processus de tonalité combinée entre ENSO et le cycle annuel, tandis que sa variabilité décennale découle en partie du rougissement océanique du bruit atmosphérique lié à la variabilité décennale du Pacifique tropical. Ensuite, en utilisant un ensemble de 62 modèles, nous démontrons que les modèles CMIP5 et 6 sont capables de simuler les principales caractéristiques spatio-temporelles de Chile Niño/Niña. Les modèles ont également tendance à simuler trop de Chile Niñas, ce qui se traduit par une asymétrie plus faible que dans les observations. Nous avons également étudié les changements des propriétés de Chile Niño/Niña dans le cadre du changement climatique en nous basant sur un ensemble de 36 modèles CMIP5/6. Nous constatons une augmentation modeste de sa variabilité, qui est due à une augmentation de l'amplitude plutôt qu'à une augmentation du nombre d'événements. Ces changements résultent d'une interaction entre des processus locaux et lointains, y compris une augmentation (diminution) de la variabilité ENSO (SPO) et des changements dans les processus locaux avec des effets opposés. Ensuite, en réalisant une série d'expériences avec un modèle atmosphérique régional couplé à une configuration océanique en dalle, nous constatons que les événements Chile Niño/Niña peuvent se produire en l'absence de dynamique océanique et peuvent résulter d'une dynamique purement interne. Les bilans thermiques de la couche de mélange révèlent que, si le rayonnement d'ondes courtes est un processus clé pour induire le développement de Chile Niño/Niña, il existe une diversité dans l'équilibre entre les processus de flux de chaleur et que le changement de la profondeur de la couche de mélange n'est pas nécessaire au développement de l'événement. Certains événements ont également besoin de la dynamique des océans pour atteindre une amplitude réaliste. Nous démontrons également son lien étroit avec le SPMM, ce qui suggère qu'il pourrait faire partie d'un mécanisme reliant la variabilité tropicale et celle des moyennes et hautes latitudes à des échelles de temps interannuelles à décennales.The eastern boundary upwelling region of the southeastern Pacific (SEP) is one of the most biologically productive oceanic areas on a global scale, which makes it highly important for food security and socio economic activities. Over recent years, marine heat waves have attracted the attention of the scientific community due to their deleterious impacts, which are projected to be exacerbated by climate change, an issue to which the SEP is particularly vulnerable to. Recently, new air-sea coupled climate modes have been identified in all major coastal upwelling systems and have been named Coastal Niños. They are thought to interact with basin-scale climate variability although it is not clear the extent to which current generation of global climate models realistically account for their statistical properties. Off Central Chile, such a mode, called Chile Niño/Niña, takes place and drives a substantial share of the local sea surface temperature variability. Improving our ability to predict these events is a significant challenge with clear societal implications for the countries close to the west coast of South America. In this thesis we investigated the underlying mechanisms of Chile Niño/Niña and its projected changes under climate change. For this we made use of observations, reanalysis products and a set of models of a wide range of complexities, from simple conceptual models and data-driven models, to full-physics climate models. A regional coupled model of intermediate complexity was also developed. We find that the South Pacific Oscillation (SPO) and the El Niño-Southern Oscillation (ENSO) are precursors of Chile Niño/Niña, while the South Pacific Meridional Mode (SPMM) has a close connection with it. Further, we show that Chile Niño/Niña near-annual variability can be interpreted as resulting from a combination tone process between ENSO and the annual cycle, while its decadal variability partly stems from oceanic reddening of atmospheric noise linked to Tropical Pacific Decadal Variability. Following, using an ensemble of 62 models, we demonstrate that CMIP5 and 6 models are skillful in simulating the main spatio-temporal characteristics of Chile Niño/Niña. Models also tend to simulate too much Chile Niñas resulting in a weaker asymmetry than in the observations. We also investigated the changes of Chile Niño/Niña properties under climate change based on an ensemble of 36 CMIP5/6 models. We find a modest increase in its variability, which is shown to be due to an increase in amplitude rather than an increase in the number of events. These changes result from an interplay of local and remote processes, including an increase (decrease) in ENSO (SPO) variability and changes in local processes with opposite effects. Amongst the local processes investigated, only the changes on the thermocline feedback show a high correlation with the change in Chile Niño/Niña variability amongst the models, emphasizing the key role of mean stratification changes along the coast. Thereafter, by performing a set of experiments with a regional atmospheric model coupled to a slab ocean configuration, we find that Chile Niño/Niña events can take place in the absence of ocean dynamics and can arise from purely internal dynamics. Mixed-layer heat budgets reveal that, while shortwave radiation is a key process to induce Chile Nino/Nina development, there is a diversity in the balance between heat flux processes and that change in mixed layer depth is not necessary for its development. Some events also need ocean dynamics to reach realistic amplitudes. Overall, we show that Chile Niño/Niña variability involves a wide diversity of local processes, and can be sustained under varied forcing conditions. We also demonstrate its tight connection with the SPMM, which suggests it could be part of a mechanism linking tropical and mid-to-high latitude variability at interannual to decadal timescales
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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