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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
Responses of two macrophytes of the genus Polygonum to water level fluctuations and interspecific competition.
No full textWater level fluctuations are common in aquatic environments and may influence directly or indirectly the spatial distribution of emergent macrophytes, causing a pattern of zonation. The most important mechanisms that determine this species zonation are their ability to tolerate environmental stressors, such as inundation, and their competitive interaction, which may vary in magnitude in an environmental gradient. In this study, we assessed the zonation of two species of emergent macrophytes, Polygonum ferrugineum and Polygonum acuminatum, as well as the mechanisms of their distribution by combining observational and experimental approaches. We modeled historical abundance data of 16 years collected from the Upper Rio Paraná Floodplain in function of depth using a Bayesian approach. Then, we designed a factorial experiment in blocks, where shoot fragments of each species were planted and grown in constant density in monocultures and mixtures and submitted to three water level treatments – low, high and variable (Ldep, Hdep and Vdep) for 30 days. All the measured response variables and relative yields (RY) were analyzed with a two-way ANOVA. The observational data showed that both species colonize different depths, evidencing zonation, in which P. acuminatum colonizes shallower areas than P. ferrugineum. Regarding the monocultures, there were no differences in biomass accumulation from either species. However, P. acuminatum showed a significant elongation of its shoot and internodes when it was grown in submersion treatments (Hdep and Vdep). This result is indicative of differential survival strategies between the two species, in which P. acuminatum resists inundation through an escape strategy, by elongating its shoot above the water surface, while P. ferrugineum showed a quiescence strategy by drastically reducing its growth rates and tolerating inundation temporarily. Regarding the mixtures, there were no difference in RY among the different treatments, indicative that water level fluctuations do not influence the magnitude of competition between these species. However, P. acuminatum showed a marginally significant advantage over P. ferrugineum, indicating that in favorable conditions, such as in constantly shallow habitats, this species might outcompete P. ferrugineum. These results are consistent with the observational results, because they show that P. acuminatum can dominate shallower areas of the littoral zone by having both morphological adaptations to intermittent fluctuations in water level and competitive advantage over P. ferrugineum. On the other hand, P. ferrugineum is limited to deeper areas, where it can tolerate inundation until favorable conditions occur. Once established it is capable of growing plagiotropic branches above the water column and colonize deeper areas than P. acuminatum.As flutuações de nível de água, comuns em ecossistemas aquáticos, podem influenciar direta ou indiretamente a distribuição espacial de macrófitas emergentes que colonizam suas zonas litorâneas, causando a zonação das espécies. Os mecanismos mais importantes que determinam a zonação de macrófitas são a capacidade de tolerância a um estresse ambiental, como a inundação e a interação competitiva, que pode variar em magnitude em um gradiente ambiental. Avaliou-se a zonação de duas espécies de macrófitas emergentes, Polygonum ferrugineum e Polygonum acuminatum e os mecanismos determinantes dessa distribuição. Para tanto, combinou-se abordagens observacionais com experimentais. Aplicou-se um modelo de regressão bayesiana em dados históricos de abundância dessas espécies em função da profundidade, coletados na planície de inundação do rio Paraná (Brasil) ao longo de 16 anos. Realizou-se também, um experimento fatorial em blocos, onde segmentos caulinares de cada espécie foram plantados em densidades constantes de monoculturas e misturas e submetidos à 3 tratamentos de nível de água – raso, fundo e variável (Ldep, Hdep e Vdep) durante 30 dias. Todas as variáveis resposta mensuradas e os índices de competição RY (“relative yield”) foram analisados com ANOVA bifatorial. Os dados observacionais mostraram que as duas espécies se distribuem em zonas diferentes, evidenciando uma zonação por profundidade, na qual P. acuminatum coloniza regiões mais rasas e P. ferrugineum as zonas mais profundas. Em relação às monoculturas, não houve diferenças no acúmulo de biomassa entre as espécies, mas P. acuminatum demonstrou um alongamento significativo do caule e dos entrenós em relação à P. ferrugineum nos tratamentos em que ocorria submersão (Hdep e Vdep). Esse resultado indica uma diferença na estratégia de sobrevivência de cada espécie, onde P. acuminatum resiste à inundação por “escape”, alongando suas partes aéreas acima do nível de água, enquanto P. ferrugineum demonstra “quiescência”, ao reduzir suas taxas de crescimento drasticamente, tolerando a inundação temporariamente. Quanto às culturas mistas, não houve diferença no índice RY entre os diferentes tratamentos, indicando que o fator inundação não influencia na magnitude da competição. No entanto, P. acuminatum demonstrou uma vantagem marginalmente significativa sobre P. ferrugineum, indicando que em condições favoráveis, como em ambientes constantemente rasos, essa espécie se sobressai sobre P. ferrugineum. Esses resultados são consistentes com a zonação observada em campo, pois indicam que P. acuminatum apresenta adaptações morfológicas às flutuações intermitentes das áreas rasas de zonas litorâneas, onde também, apresenta vantagem competitiva. Por sua vez, P. ferrugineum é limitado às áreas mais profundas, onde tolera a inundação mais constante até condições favoráveis se estabelecerem, quando, então, é capaz de lançar ramos plagiotrópicos sobre a coluna de água, colonizando maiores profundidades do que P. acuminatum.Master
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
Responses of two macrophytes of the genus Polygonum to water level fluctuations and interspecific competition.
No full textWater level fluctuations are common in aquatic environments and may influence directly or indirectly the spatial distribution of emergent macrophytes, causing a pattern of zonation. The most important mechanisms that determine this species zonation are their ability to tolerate environmental stressors, such as inundation, and their competitive interaction, which may vary in magnitude in an environmental gradient. In this study, we assessed the zonation of two species of emergent macrophytes, Polygonum ferrugineum and Polygonum acuminatum, as well as the mechanisms of their distribution by combining observational and experimental approaches. We modeled historical abundance data of 16 years collected from the Upper Rio Paraná Floodplain in function of depth using a Bayesian approach. Then, we designed a factorial experiment in blocks, where shoot fragments of each species were planted and grown in constant density in monocultures and mixtures and submitted to three water level treatments – low, high and variable (Ldep, Hdep and Vdep) for 30 days. All the measured response variables and relative yields (RY) were analyzed with a two-way ANOVA. The observational data showed that both species colonize different depths, evidencing zonation, in which P. acuminatum colonizes shallower areas than P. ferrugineum. Regarding the monocultures, there were no differences in biomass accumulation from either species. However, P. acuminatum showed a significant elongation of its shoot and internodes when it was grown in submersion treatments (Hdep and Vdep). This result is indicative of differential survival strategies between the two species, in which P. acuminatum resists inundation through an escape strategy, by elongating its shoot above the water surface, while P. ferrugineum showed a quiescence strategy by drastically reducing its growth rates and tolerating inundation temporarily. Regarding the mixtures, there were no difference in RY among the different treatments, indicative that water level fluctuations do not influence the magnitude of competition between these species. However, P. acuminatum showed a marginally significant advantage over P. ferrugineum, indicating that in favorable conditions, such as in constantly shallow habitats, this species might outcompete P. ferrugineum. These results are consistent with the observational results, because they show that P. acuminatum can dominate shallower areas of the littoral zone by having both morphological adaptations to intermittent fluctuations in water level and competitive advantage over P. ferrugineum. On the other hand, P. ferrugineum is limited to deeper areas, where it can tolerate inundation until favorable conditions occur. Once established it is capable of growing plagiotropic branches above the water column and colonize deeper areas than P. acuminatum.CNPq; CAPESAs flutuações de nível de água, comuns em ecossistemas aquáticos, podem influenciar direta ou indiretamente a distribuição espacial de macrófitas emergentes que colonizam suas zonas litorâneas, causando a zonação das espécies. Os mecanismos mais importantes que determinam a zonação de macrófitas são a capacidade de tolerância a um estresse ambiental, como a inundação e a interação competitiva, que pode variar em magnitude em um gradiente ambiental. Avaliou-se a zonação de duas espécies de macrófitas emergentes, Polygonum ferrugineum e Polygonum acuminatum e os mecanismos determinantes dessa distribuição. Para tanto, combinou-se abordagens observacionais com experimentais. Aplicou-se um modelo de regressão bayesiana em dados históricos de abundância dessas espécies em função da profundidade, coletados na planície de inundação do rio Paraná (Brasil) ao longo de 16 anos. Realizou-se também, um experimento fatorial em blocos, onde segmentos caulinares de cada espécie foram plantados em densidades constantes de monoculturas e misturas e submetidos à 3 tratamentos de nível de água – raso, fundo e variável (Ldep, Hdep e Vdep) durante 30 dias. Todas as variáveis resposta mensuradas e os índices de competição RY (“relative yield”) foram analisados com ANOVA bifatorial. Os dados observacionais mostraram que as duas espécies se distribuem em zonas diferentes, evidenciando uma zonação por profundidade, na qual P. acuminatum coloniza regiões mais rasas e P. ferrugineum as zonas mais profundas. Em relação às monoculturas, não houve diferenças no acúmulo de biomassa entre as espécies, mas P. acuminatum demonstrou um alongamento significativo do caule e dos entrenós em relação à P. ferrugineum nos tratamentos em que ocorria submersão (Hdep e Vdep). Esse resultado indica uma diferença na estratégia de sobrevivência de cada espécie, onde P. acuminatum resiste à inundação por “escape”, alongando suas partes aéreas acima do nível de água, enquanto P. ferrugineum demonstra “quiescência”, ao reduzir suas taxas de crescimento drasticamente, tolerando a inundação temporariamente. Quanto às culturas mistas, não houve diferença no índice RY entre os diferentes tratamentos, indicando que o fator inundação não influencia na magnitude da competição. No entanto, P. acuminatum demonstrou uma vantagem marginalmente significativa sobre P. ferrugineum, indicando que em condições favoráveis, como em ambientes constantemente rasos, essa espécie se sobressai sobre P. ferrugineum. Esses resultados são consistentes com a zonação observada em campo, pois indicam que P. acuminatum apresenta adaptações morfológicas às flutuações intermitentes das áreas rasas de zonas litorâneas, onde também, apresenta vantagem competitiva. Por sua vez, P. ferrugineum é limitado às áreas mais profundas, onde tolera a inundação mais constante até condições favoráveis se estabelecerem, quando, então, é capaz de lançar ramos plagiotrópicos sobre a coluna de água, colonizando maiores profundidades do que P. acuminatum.28 f. : il
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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