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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
EVENTOS EXTREMOS DE MOVIMENTOS DE MASSA: REFLEXÕES A PARTIR DE INVENTÁRIOS E MODELAGEM EMPÍRICA
No full textOs eventos extremos de movimentos de massa representam momentos de ruptura no equilíbrio dinâmico das encostas, com alto potencial destrutivo e capacidade de reconfigurar a paisagem. Este artigo discute a natureza desses eventos no Brasil, articulando conceitos geomorfológicos com a análise de casos recentes. Argumenta-se que a relação entre o impulso pluviométrico e a resposta geomorfológica é intrinsecamente não linear. Evidências de eventos de alta magnitude, como os ocorridos no Planalto do Paraitinga (SP/2010) e no Rio Grande do Sul (2024), indicam a existência de limiares pluviométricos funcionais que, quando ultrapassados, desencadeiam uma mudança de regime nos processos deflagradores. Acima desses limiares, observa-se um aumento abrupto na severidade dos movimentos de massa, uma alteração na distribuição de tamanhos das cicatrizes e uma menor influência dos fatores topográficos locais, sugerindo a atuação de mecanismos hidrológicos mais profundos. Conclui-se que os modelos empíricos de previsão baseados em eventos recorrentes de baixa magnitude são insuficientes para prever a severidade desses eventos extremos, sendo necessárias abordagens que capturem essas transições não lineares e os complexos controles hidrogeomorfológicos associados
Geomorphodynamics of slope-channel coupling in high-magnitude events: insights into landslides in Paraitinga Plateau (SP)
No full textA parte alta dos vales, junto às cabeceiras de drenagem e às vertentes de alta declividade têm uma geomorfodinâmica particular, dependente da natureza dos processos nessa zona de interação entre vertente e canal. Considerando que ainda há uma lacuna na compreensão destes sistemas geomorfológicos no Brasil e que estes vales podem ser profundamente perturbados por eventos de alta magnitude que provocam a ocorrência de processos como movimentos de massa generalizados e fluxos de detritos, o objetivo desta pesquisa foi investigar se a geomorfodinâmica dos vales e canais na zona de interação vertente-canal no Planalto do Paraitinga é influenciada pelo trabalho de entalhe, transporte e deposição dos movimentos de massa, particularmente dos fluxos de detritos deflagrados por eventos de alta magnitude. Para isso procedemos à identificação dos limiares pluviométricos capazes de gerar escorregamentos e fluxos de detritos e seus intervalos de recorrência, à análise dos fatores que influenciaram a magnitude e a frequência espacial dos escorregamentos e a sua mobilização em fluxos de detritos; ao mapeamento da geomorfodinâmica do evento de 2009/2010, à análise de campo das zonas erosiva e deposicional dos fluxos de detritos e processos associados e à caracterização morfológica e morfométrica do perfil longitudinal dos vales. Os resultados obtidos mostraram que a mobilização dos sedimentos dos vales da zona de interação vertente-canal no evento de 2009/2010 se deu principalmente por fluxos de detritos, mas provavelmente também por enxurradas de detritos e fluxos hiperconcentrados. Estes processos estão espacialmente associados a escorregamentos generalizados e escorregamentos de grande magnitude que parecem depender de processos deflagradores específicos que acabam por facilitar a liquefação da massa escorregada. Os sedimentos depositados nos vales da zona de interação vertente-canal são mobilizados em quantidade significativa somente durante eventos chuvosos de alta magnitude e baixa frequência. Os fluxos de detritos do evento de 2009/2010 deixaram como principais marcas na paisagem os canais em leito rochoso e depósitos na forma de diques e lóbulos de detritos. Estes canais em leito-rochoso na zona de interação vertente-canal diferem dos canais em leito rochoso a jusante pela ausência ou ocorrência incipiente de feições abrasivas fluviais, bem como pela frequência relativamente alta de feições erosivas de impacto por arrancamento (plucking). As relações entre a declividade e a área de contribuição ao longo dos perfis longitudinais apresentaram uma quebra de tendência clara entre o domínio de processos fluviais e o domínio dos fluxos de detritos, que pôde ser usada com alto grau de acerto para prever os locais de incisão de outros prováveis fluxos de detritos ocorridos no evento de 2009/2010. Apesar disso, a presença de possíveis horizontes orgânicos enterrados sob os depósitos do evento de 2009/2010, assim como a percepção de menores taxas de processos geomorfológicos como escorregamentos e fluxos de detritos em áreas florestadas, sugerem um controle climático na recorrência dos eventos e uma influência antrópica na frequência atual dos processos erosivos e deposicionais na zona de interação vertente-canal do Planalto do ParaitingaThe upper reaches of valleys, near drainage heads and steep slopes, exhibit a distinct geomorphic dynamic that depends on the nature of processes occurring in slopechannel coupling. Given the existing knowledge gap concerning these geomorphic systems in Brazil, and considering that these valleys can be profoundly affected by highmagnitude events leading to widespread mass movements and debris flows, the aim of this research was to investigate whether the geomorphic dynamics of valleys and channels in the slope-channel coupling in the Paraitinga Plateau is influenced by the processes of incision, transport, and deposition of landslides, particularly debris flows triggered by high-magnitude events. To achieve this, we identified the rainfall thresholds capable of triggering landslides and debris flows, along with their recurrence intervals. We analyzed factors influencing the magnitude and spatial frequency of landslides, and their mobilization into debris flows. Geomorphic dynamics during the 2009/2010 event were mapped, including field analysis of erosional and depositional zones of debris flows and associated processes. The longitudinal profiles of the valleys were also characterized. Results demonstrated that sediment mobilization in the valleys of the slope-channel coupling during the 2009/2010 event was primarily driven by debris flows, possibly also involving debris floods and hyper-concentrated flows. These processes were spatially linked to widespread landslides and largemagnitude landslides, which seemed to depend on specific triggering processes that facilitated the liquefaction of the mass involved. The sediments deposited in the valleys of the slope-channel coupling are mobilized in significant amounts only during highmagnitude, low-frequency rain events. The debris flows from the 2009/2010 event left notable landscape features, such as rocky bed channels and deposits in the form of debris levees and lobes. These rocky bed channels within the slope-channel interaction zone differed from downstream rocky bed channels due to the absence or incipient occurrence of fluvial abrasive features, as well as the relatively high frequency of impact-driven erosional features (plucking). Relationships between slope and drainage area along the longitudinal profiles exhibited scaling break between the domain of fluvial processes and the domain of debris flows. This change provided a high degree of accuracy in predicting incision locations for other probable debris flows during the 2009/2010 event. However, the presence of potential buried organic horizons beneath the deposits from the 2009/2010 event, along with the observation of lower rates of geomorphic processes such as landslides and debris flows in forested areas, suggested a climatic control on event recurrence and anthropogenic influence on the current frequency of erosional and depositional processes within the slope-channel coupling of watersheds of the Paraitinga Platea
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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