1,721,125 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
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
Electronic states of BP, BP(+)BP(-), B(2)P(2), B(2)P(2)(-) and B(2)P(2)(+)
No full textInternational audienceUsing augmented sextuple zeta basis sets and internally contracted multireference configuration interaction (MRCI) wavefunctions, potential energy, electric dipole and transition moments have been computed for the X(3)Pi, a(1)Sigma(+), b(1)Pi and A(3)Sigma(-) states of BP, X(2)Sigma(+) and A(2)Pi states of BP(-) and X(4)Sigma(-) and A(4)Pi states of BP(+). From these data spectroscopic constants, radiative transition probabilities and photoelectron spectra of BP- and BP have been evaluated. The non-vanishing spin-orbit coupling elements between the four low lying triplet and singlet states of the neutral BP have also been calculated from MRCI wavefunctions. The treatment of the corresponding perturbations in the manifold of dense rovibrational states in the three lowest states would require a precise knowledge of the electronic excitation energies. Our best singlet-triplet separations (X-a) are calculated to be 2412 cm(-1) (MRCI) and 2482 cm(-1) (restricted coupled cluster with perturbative triples (RCCSD(T))) with an estimated error bound of about +/ 200 cm(-1). All three states have long radiative lifetimes with cascading among the rovibrational levels of different states. The ionization energy IE(e) of BP is calculated to be 9.22 eV (MRCI) and 9.48 eV (RCCSD(T)), the electron affinity EA(e) 2.51 eV (MRCI) and 2.74 eV (RCCSD(T)). The photoelectron spectra of BP and BP- have been obtained from the Franck-Condon factors of the MRCI potentials. For the UV spectroscopy the dipole allowed radiative transition probabilities are given for A(3)Sigma(-) X(3)Pi, b(1)Pi a(1)Sigma(+) of BP, A(2)Pi X(2)Sigma(+) of BP and A(4)Pi X(4)Sigma(-) of BP(+). The ionization energy IE(e) of B(2)P(2) of 8.71 eV and the electron affinity EA, of 2.34 eV have been calculated by the RCCSD(T)/aVQZ approach. Also the harmonic vibrational wavenumbers for the electronic ground states of the ions B(2)P(2)(+) and B(2)P(2)(-) are given
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
Study of ultra-fast coupled electron-nuclear processes by quantum dynamics with time-dependent gaussian functions
No full textNotre compréhension de la chimie est ancrée dans l'approximation de Born-Oppenheimer où les évolutions temporelles des électrons et noyaux sont séparées avec les électrons s'adaptant instantanément aux mouvements des noyaux. Le développement de sources lumineuses d'impulsions toujours plus courtes nous permet d'aller au-delà de cette séparation vers une nouvelle chimie en interagissant avec la matière sur une échelle de temps de l'ordre de la femtoseconde. À cette échelle apparaissent de nouveaux processus pour lesquels la séparation temporelle entre électrons et noyaux n'a plus de sens. C'est ce que montre une récente expérience mettant en évidence l'impact de la dynamique électronique sur le mécanisme d'un transfert de proton dans la glycine. Ce type d'étude apporte de nouvelles informations sur l'évolution des molécules biologiques, telles que les protéines, exposées à une irradiation intense. Cela permet aussi d'explorer l'importance des couplages électrons/noyaux à la naissance de la réaction chimique et ouvre la voie vers un nouveau type de contrôle de la chimie sur des temps très courts. La nature pionnière de ces expériences nécessite le travail conjoint d'expérimentateurs et de théoriciens. Une description théorique fait face à deux difficultés majeures : i) l'échelle de temps très courte implique la participation d'un très grand nombre d'états électroniques ii) une description totalement quantique est nécessaire pour rendre compte des couplages électrons/noyaux. Le but de ce projet est de tester une nouvelle approche pour contourner les difficultés théoriques et modéliser les processus à l'échelle de la femtoseconde avec des applications allant au-delà de l'étude de la glycine. Dans cette approche, électrons et noyaux sont décrits à l'aide de fonctions gaussiennes dépendantes du temps pour représenter la fonction d'onde moléculaire. Les approches théoriques usuelles sont limitées par l'obtention préalable des états électroniques stationnaires (adiabatiques) dans le champ des noyaux statiques. Ces états ne sont cependant pas optimaux pour décrire la dynamique dans les états hautement excités et sont numériquement coûteux. Un premier aspect de ce projet est de contourner cette difficulté en utilisant une approche dépendante du temps pour les états électroniques. Pour ce faire, il sera nécessaire de développer une interface avec les outils de chimie quantique déjà existants. Un deuxième aspect sera le développement d'une méthode de dynamique quantique des noyaux adaptée à ce formalisme. L'approche choisie utilisera une base de fonctions gaussiennes dépendantes du temps. Ces fonctions présentent l'avantage d'être localisées, ce qui permet une interface simple avec les méthodes de chimie quantique et rend possible l'utilisation de méthodes classiques pour générer la dynamique de ces fonctions. Des tests seront effectués sur des systèmes modèles avec un petit nombre de particules et en dimension réduite avant d'appliquer la méthode sur des cas de transfert de proton couplés à des transferts de charge tels que dans le système [He-H-He]+. La méthode sera par la suite appliquée à l'étude du transfert de protons dans la glycineOur understanding of chemistry is rooted in the Born-Oppenheimer approximation, which separates the temporal evolution of electrons from that the nuclei. In this approximation, the electrons instantaneously adopt to the nuclei' motions. The constant development of light sources for shorter pulses allows one to beyond this sepatation by interacting with matter on a femtosecond timescale. New fenomena appear at this scale and the temporal separtion between electron and nuclei is no more possible. A recent experiment illustrates this by providing evidence thatt electronic dynamics impacts a proton transfer mechanism in glycine. Such experiments bring important data regarding biomolecules dynamics under high radiation. They also shed light on the importance of the coupled electrons/nuclei at the bright of a chemical reaction and open the possibility o controlling chemistry on etremely short timescales. The pioneering nature of these experiments demands a concerted work from experimentalsts and theoriticians. A theorical description faces two major difficulties : i) the very short timescale implies that a high number of electronic states are involved and ii) a fool quantum description is required to model the electrons/nuclei couplings. The aim of this project is to assess a new approach for avoiding these theorical difficulties and to model proccesses and the fentosecond timescale for applications beyond the study of glycine. In this approach electrons and nuclei are described by the time-dependent Gaussian functions that combined to build the molecular wavefunction. This approach combines time-dependent Gaussian functions for electrons and nuclei to build the molecular wave-function. Usual approach are limited by obtaining first the stationary electronic (adiabatic) states in the field of static nuclei. Such states are however not adapted to describe highly excited states dynamics and are numerically costly. A first direction we will pursue is to employ time-dependent electonic states. For this purpose we will need to develop and interface with already developed electronic structure tools. A secod direction of this project is to develop a quantum dynamical method for the nuclei that is adapted to this formalism. We chose time-dependent Gaussian basis functions. The advantage of such functions resides in their local nature, which allows for a simple connection with electronic structure methods and makes possible the use of classical approach to generate the Gaussian' dynamics. We will conduct tests on model systems with a small number of particles in reduced dimensions before applying investigating coupled proton-charge transfer processes in systems such as [He-He-He]+. The method will subsequently applied to investigate the proton transfer mechanism in glycin
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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