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
Finite-difference schemes for transport-dominated equations using special collocation nodes
No full textWe introduce finite-difference schemes based on a special upwind-type collocation grid, in order to obtain approximations of the solution of linear transport-dominated advection-diffusion problems. The method is well suited when the diffusion parameter is very small compared to the discretization parameter. A theory is developed and many numerical experiments are shown
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
Finite-difference preconditioners for superconsistent pseudospectral approximations
No full textThe superconsistent collocation method, which is based on a collocation grid different from the one used to represent the solution, has proven to be very accurate in the resolution of various functional equations. Excellent results can be also obtained for what concerns preconditioning. Some analysis and numerous experiments, regarding the use of finite-differences preconditioners, for matrices arising from pseudospectral approximations of advection-diffusion boundary value problems, are presented and discussed, both in the case of Legendre and Chebyshev representation nodes
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
A novel numerical technique to investigate nonlinear guided waves: approximation of nonlinear Schroedinger equation by nonperiodic pseudospectral methods
No full textA new numerical technique for investigating light waves guided by planar nonlinear dielectric films is presented. The method implements a multidomain spectral type approximation based on orthogonal algebraic polynomials, and makes possible to deal with nonperiodic boundary conditions and discontinuities of the data, overcoming the known deficiencies of the trigonometric polynomials. Results of preliminary numerical experiments for the solution of the nonlinear Schrödinger equation are presented
Successful pregnancies following an egg donation program in women with previously treated Hodgkin's disease
No full textIn order to draw attention not only to patients affected by a neoplasia, but also to those who may have problems of sterility, we describe six women affected by Hodgkin's disease who had precocious menopause due to chemotherapy and/or radiotherapy but who were safely delivered of children. These pregnancies were achieved through oocyte donation, in vitro fertilization and intrauterine embryo transfer or oocyte intracytoplasmic insemination. During natural or iatrogenic menopause, the uterus preserves its capacity to respond to steroidal hormones and to permit implantation and development of an embryo. Our study concerns six young females with iatrogenic menopause caused by treatment of Hodgkin's disease who carried a pregnancy to term. The pregnancies were achieved by oocyte donation, in vitro fertilization and intrauterine embryo transfer or oocyte intracytoplasmic insemination. Endometrial maturation was obtained by administration of estradiol and progesterone. Steroidal therapy was administered until the 13th-14th week in relation to placental function. Five of the 6 females underwent Caesarean section because of a twin birth or complications during the third trimester of pregnancy (gestosis). All the delivered children are, to date, well; their median age is 4 years. This study confirms the possibility of women treated for Hodgkin's disease being able to carry a pregnancy safely to term with the help of steroidal therapy. Careful clinical and obstetric surveillance is important. Focusing attention on long-term survivors of Hodgkin's disease, we set the goal of improving the quality of life of these patients, considering their psychophysical well-being as a whole. Greater attention to the problems of safeguarding fertility in these patients would be advisable, also in the light of legislative regulation of medical care techniques in various countries
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