1,721,258 research outputs found
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
Structural changes in succession of phosphorus-fertilized secondary forests with pasture history in central Amazonia
No full textSecondary forests with pasture history are regenerating in soils degraded by the intensive use of fire as a pasture management technique and by compaction caused by cattle trampling. The nutritional limitation, mainly for P, reported in great part of the soils of the Amazon Basin, can be aggravated by this type of soil use and, consequently, affect the natural regeneration after the abandonment of the area. Therefore, the main objective of this study was to analyze whether phosphate fertilization and soil acidity correction affect the structural characteristics of secondary forests in a chronosequence (different initial ages) with pasture history in central Amazonia. Ten secondary forests were fertilized in 2000, with four treatments each: phosphorus, phosphorus + liming, phosphorus + liming + gypsum and an unfertilized control. Five censuses were carried out between 2001 and 2005, the last one being in 2018, for calculation of aboveground biomass, stem density and individual mass average. Aboveground biomass stock and average individual mass of older forests increased during the successional trajectory in the control treatment, with no significant difference between P fertilization and control. In forests fertilized by P + Ca, the aboveground biomass stock decreased over time while the average individual mass increased. In forests fertilized by P + Ca + G, both aboveground biomass stock and average individual mass decreased over time. Fertilization did not affect stem density, which decreases during the successional trajectory. These results suggest a possible allocation of growth to belowground biomass and effect of phosphate fertilization and correction of soil acidity on the dynamics and floristic composition of secondary forests with pasture history.Florestas secundárias com histórico de pastagem estão se regenerando em solos degradados pelo uso intensivo do fogo como técnica de manejo do pasto e pela compactação causada pelo pisoteio do gado. A limitação nutricional, principalmente por fósforo, relatada em grande parte dos solos da Bacia Amazônica, pode ser agravada por esse tipo de uso solo e, consequentemente, afetar a regeneração natural após o abandono da área. Portanto, o principal objetivo deste estudo foi analisar se a fertilização fosfatada e correção da acidez do solo afetam as características estruturais de florestas secundárias em uma cronossequência (diferentes idades iniciais) com histórico de pastagem na Amazônia central. Dez florestas secundárias foram fertilizadas em 2000, com quatro tratamentos cada: fósforo, fósforo + calagem, fósforo + calagem + gessagem e um controle não fertilizado. Foram realizados 5 censos entre 2001 e 2005, sendo o último em 2018, para cálculo de biomassa acima do solo, densidade de caules e massa média individual. O estoque de biomassa acima do solo e massa média individual das florestas mais velhas aumentaram ao longo da trajetória sucessional no tratamento controle, sem diferença significativa entre fertilização por P e controle. Nas florestas fertilizadas por P+Ca, o estoque de biomassa acima do solo diminuiu ao longo do tempo enquanto a massa média individual aumentou. Nas florestas fertilizadas por P+Ca+G, tanto o estoque de biomassa acima do solo quanto a massa média individual reduziram ao longo do tempo. A fertilização não afetou a densidade de caules, que diminui ao longo da trajetória sucessional. Estes resultados sugerem uma possível alocação do crescimento para a biomassa abaixo do solo e efeito da fertilização fosfatada e correção da acidez do solo na dinâmica e composição florística de florestas secundárias com histórico de pastagem
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
Variação temporal e espacial na produtividade de raízes finas em uma floresta da Amazônia central
Full text linkUnderstanding the primary productivity in many ecosystems, including tropical forests is
necessary due to the scarcity of information on many of its components, as well as its
importance in the carbon cycle in terrestrial ecosystems. Most studies have focused on
investigating the productivity of forests in their above-ground components, so that little is
known yet about the dynamics of productivity and nutrient cycling made by the roots below
ground, which is mainly linked to difficult to have to study this compartment in forest
ecosystems. Moreover, the few studies on the productivity of existing roots in the Amazon,
were made in a small number of plots and on short time, so that was given little attention to
the spatial variability and temporal productivity of fine roots. In this context stocks and
productivity of fine roots (Rp) were evaluated in 9 plots of 0,5 ha in upland forests located in
the Forest Reserve Adolfo Ducke. The soils had their physical and chemical properties
evaluated over time. Having been to Rp analyzed in relation to the role of controlling
environmental factors and regional topographic position (plateaux, slope and valley bottoms).
The areas of plateaux had a lower value of Rp (1,58±0,12 Mg C ha-1 yr-1) when compared
with the valley bottoms (2,48±0,28 Mg C ha-1 yr-1). The slope areas behaved similarly to
plateaux areas with 1,57±0.08 Mg C ha-1 yr-1. As to the residence time in the soil fine roots in
the areas of valley bottoms have an average time of 5 months and the areas of plateaux 3 on
average three months. The Rp was not sensitive to the availability of nutrients in the soil, but
it seems to respond to the levels of water availability, but in a complex way. The forest
structure has also strong influence on levels of Rp. Net primary productivity (NPP) was
calculated with literature data of assistance to the same study plots in 8,34 Mg C ha-1 yr-1 to
plateaux, 7,82 Mg C ha-1 yr-1 for slope area and 7,81 Mg C ha-1 yr-1 for the velley bottoms
respectively. However allocation between above and below ground was different with valley
bottoms average allocating the NPP 32% below ground, while plateaux + slope area allocated
only 19,8%. The morphology of the fine roots of the slopes and valley bottoms showed no
changes regarding the availability of water in as the plateaus in the dry season had higher
mortality. The information presented here has the potential to contribute to the improvement
of regional estimates of primary productivity in the Amazon, allowing modeling its dynamics
from other variables more easily measurable, especially precipitation and forest biomass.A compreensão da produtividade primária em muitos ecossistemas, incluindo florestas
tropicais faz-se necessária, devido à escassez de informações em vários de seus componentes,
assim como sua importância no ciclo do carbono em ecossistemas terrestres. A maior parte
dos estudos tem enfocado em investigar a produtividade das florestas nos seus componentes
acima do solo, de forma que pouco se conhece ainda sobre a dinâmica da produtividade e da
ciclagem de nutrientes feitas pelas raízes abaixo do solo, o que está ligado principalmente à
dificuldade de se tem em estudar esse compartimento em ecossistemas florestais. Além disso,
os poucos estudos sobre produtividade de raízes existentes na Amazônia, foram feitos em um
número pequeno de parcelas e sobre curto intervalo de tempo, de forma que foi dada pouca
atenção à variabilidade espacial ou temporal da produtividade de raízes finas. Neste contexto
os estoques e a produtividade de raízes finas (RP) foram avaliadas em 9 parcelas de 0,5 ha em
florestas de terra firme localizadas na Reserva Florestal Adolfo Ducke. Os solos tiveram suas
propriedades físicas e químicas avaliadas ao longo do tempo. Tendo sido a Rp analisadas em
relação ao papel controlador dos fatores ambientais e da posição topográfica regional (platô,
vertente e baixio). As áreas de platô tiveram um menor valor de RP (1,58±0,12 Mg C ha-1 ano-
1) quando comparada com os valores de baixio (2,48±0,28 Mg C ha-1 ano-1). As áreas de
vertente se comportaram de forma semelhante às áreas do platô com 1,57±0,08 Mg C ha-1
ano
-1. Em quanto ao tempo de residência no solo as raízes finas nas áreas de baixio têm em
media um tempo de 5 meses e as áreas de platô 3 em media três meses. A RP não se mostrou
sensível à disponibilidade de nutrientes no solo, mas parece responder aos níveis de
disponibilidade de água, porém de forma complexa. A estrutura da floresta tem também forte
influência nos níveis de Rp. A produtividade primária líquida (PPL) foi calculada, com auxilio
de dados da literatura para as mesmas parcelas de estudo, em 8,34 Mg C ha-1 ano-1 para platô,
7,82 Mg C ha-1 ano-1 para a vertente e 7,81 Mg C ha-1 ano-1 para o baixio, respectivamente.
Entretanto a alocação entre acima e abaixo do solo foi diferente, com baixios alocando em
média 32% da PPL abaixo do solo enquanto platô+vertente alocaram apenas 19,8%. A
morfologia das raízes finas das vertentes e baixios não apresentaram mudanças em relação a
disponibilidade de agua, em quanto os platôs na estação seca tiveram maior mortalidade. As
informações aqui apresentadas tem potencial para contribuir para o aperfeiçoamento das
estimativas regionais de produtividade primária na Amazônia, permitindo modelar sua
dinâmica a partir de outras variáveis mais facilmente mensuráveis, notadamente a
precipitação e a biomassa florestal
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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