1,720,966 research outputs found
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
Dinâmica de sistemas bipartites de spins no espaço de fase quântico discreto
No full textQuando temos sistemas quânticos sem análogo clássico a descrição de Weyl- Wigner, para o espaço de fase quântico, não pode ser utilizada, pois a mesma não representa graus de liberdade associados a grandezas discretas. Um exemplo desses sistemas são os estados emaranhados bipartites de spin 1/2. Para tal, se faz necessária a descrição de um espaço de fase quântico discreto e de dimensão finita. Nessa descrição é possível se obter a caracterização do emaranhamento, bem como quantificar o grau dessas correlações entre os sub sistemas; além do que, há a possibilidade de calcular a evolução temporal nessa descrição, tanto para o sistema como um todo quanto para o emaranhamentoFor quantum systems without classical analog the Weyl-Wigner description associated to quantum phase space can not be used, since it does not represent degrees of freedom associated with discrete quantities. An example of these systems are spin 1/2 bipartite entangled states. For them, it is needed a discrete quantum phase space description which have nite dimension. In this description, it is possible to obtain entanglement characterization, and to quantify the correlation degree between the subsystems; there is also the possibility of calculating the time evolution, in this description, both for the system as a whole as well as for the entanglementCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
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
Correlações genuínas multipartidas em sistemas invariantes por permutações de partículas
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Física, Florianópolis, 2022.Sistemas invariantes por permutações de partículas estão presentes em muitos modelos físicos, tais como o modelo Lipkin-Meshkov-Glick (LMG), modelo de Dicke, modelo do Cristal Temporal de Fronteira (CTF), entre outros. Esses sistemas possuem fenômenos críticos nos quais o conhecimento da correlação desempenha um papel fundamental, principalmente para descrever Transição de Fase Quântica (TFQ). Geralmente, as correlações, como emaranhamento e discórdia quântica, são estudadas entre bipartições, ou entre todos os N subsistemas para estados puros. A questão se k partículas quaisquer estão genuinamente correlacionadas é menos restrita e mais informativa, sendo abordada muito recentemente na literatura. Assim, o objetivo desta tese é estudar as correlações genuínas k-partidas em dois sistemas invariantes por permutação de partículas, o modelo LMG e o modelo CTF. Além disso, investigamos a presença de emaranhamento genuíno k-partido no modelo CTF, uma vez que o emaranhamento é um recurso importante em tarefas quânticas. O primeiro modelo estudado é o modelo LMG, um modelo que pode ser representado por N spins 1/2 com interações de alcance infinito, com um campo magnético sendo aplicado transversalmente à cadeia de spins. Nesse modelo, verificamos que as ordens de Correlações Genuínas Multipartidas (CGM) assinalam a TFQ de segunda ordem, tal como é conhecido que outras medidas de correlações, como emaranhamento e discórdia quântica, também o fazem. Além disso, notamos que as correlações genuínas k-partidas apresentam um comportamento não trivial com a variação da ordem de correlação. A explicação desse comportamento está ligada ao número de partições dos estados produto utilizados para calcular CGM. Além disso, calculamos através do Escalonamento de Tamanho Finito (ETF) os expoentes críticos para várias ordens de CGM, observando que os expoentes estão num intervalo de [-1/2,1/2] e conjecturamos que todas as ordens estão neste intervalo. O segundo modelo analisado nesta tese é o modelo do CTF, um estado da matéria de não-equilíbrio em contato com um ambiente que quebra a simetria de translação temporal. Mostramos que as CGM captam as oscilações da fase CTF e com análises de escalonamento das correlações totais, constatamos também que o tempo de vida das oscilações diverge no limite termodinâmico, no qual emerge o fenômeno do CTF. Além disso, no Estado Estacionário de Não Equilíbrio (EENE) observamos que as CGM são extensivas com número de partículas na fase CTF, enquanto que são subextensivas na fase ferromagnética. As CGM contam as correlações clássicas e quânticas na medida, então para saber se há emaranhamento genuíno k-partido nas duas fases do modelo, utilizamos a Informação quântica de Fisher (IQF) como testemunha. Verificamos que há emaranhamento genuíno k-partido na fase ferromagnética, contudo, nada pode ser dito na fase CTF na qual a IQF não testemunha emaranhamento genuíno k-partido. Através de uma análise de mapa de cores da matriz de densidade do EENE, mostramos que na fase CTF o estado se aproxima de um estado superradiante, que não é emaranhado, porém tem uma grande quantidade de CGM.Abstract: Systems invariant by particle permutations are present in many physical models, such as LMG model, Dicke model, CTF model, among others. These systems possess critical phenomena where the knowledge of correlation plays a key role, mainly to describe TFQ. Generally, the correlations, such as with entanglement entropy and quantum discord, are studied between bipartitions, or among all the subsystems for pure states. The question if k-particles are genuinely correlated is less restricted and more informative, being addressed very recently in the literature. So, the objective of this thesis is to study the genuine k-partite correlations in two systems invariant by particle permutation, the LMG model and the CTF model. In addition, we investigate the presence of genuine k-partite entanglement in the CTF model, since entanglement is an important resource in quantum tasks. The first model studied is the LMG model, a model that can be represented by N spins 1/2 with infinite range interactions, with a magnetic field applied transversely to the spins chain. In this model, we verify that all orders of CGM signal the second order TFQ, as other measures of correlations, such as entanglement and quantum discord, also do. Additionally, we notice that the genuine k-partite correlations present a non-trivial behavior with the variation of the correlation order. The explanation of this behavior is linked to the number of partitions of the product state used to calculate CGM. Furthermore, we calculate through ETF the critical exponents for several orders of CGM, observing that the exponents are in an interval [-1/2,1/2] and we conjecture that all orders of CGM are in this interval. The second model analyzed in this thesis is the CTF model, a non-equilibrium state of matter in contact with an environment that breaks time translation symmetry. We show that the CGM capture the oscillations of the CTF phase and with scaling analyses of total correlations we also verify that the lifetime of the oscillations diverges in the thermodynamic limit, where the CTF phenomenon emerges. Moreover, in the EENE we observe that the CGM are extensive with particle number in the CTF phase, while they are subextensive in the ferromagnetic phase. The CGM count the classical and quantum correlations in the measure, then to know if there are genuine k-partite entanglement in the phases of the model, we use IQF as a witness. We find that there are genuine k-partite entanglement in the ferromagnetic phase, however, nothing can be said in the CTF phase where the IQF does not witness genuine k-partite entanglement. Through a color map analyses of the density matrix of the EENE, we show that in the CTF phase the state approaches a superradiant state, which is not entangled but it has a great amount of CGM
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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