1,721,459 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
Risk Management in the Treatment of Malignant Gliomas with BCNU Wafer Implants
No full textImplantation of BCNU wafers (Gliadel (R)) into the resection cavity has demonstrated a survival benefit for patients with newly diagnosed malignant gliomas. The follow-up of two phase III trails has further shown that the number of long-term survivors was significantly increased by BCNU wafer treatment. BCNU wafer implantation may be integrated into current multimodal first line strategies. In the setting of recurrent disease BCNU wafer implantation has also shown a survival benefit and now extends the treatment options in a patient population that typically has undergone extensive pretreatment. An analysis of the literature has helped to clearly identify the risks associated with topic BCNU treatment. Here we summarize the incidence and time course of adverse events associated with local chemotherapy and propose solutions. The growing body of experience with BCNU wafer implantation may serve as a basis to develop adequate risk management strategies with regard to patient selection, surgical techniques, and follow-up schedules
Genomic structure of the 5 ' end of the porcine ryanodine receptor 3 gene (RYR3)
No full textRyanodine receptor 3 is a calcium channel located in the membrane of the endoplasmic reticulum. We isolated eight overlapping PAC clones from the porcine ryanodine receptor 3 gene (RYR3) and determined the DNA sequences of the first and second exon together with 5.8 kb of 5' flanking region and 10.3 kb of intron sequences. By comparing the porcine genomic sequence to the human RYR3 cDNA sequence the porcine transcription start site could be mapped to a GC-rich region. Physical mapping of the isolated PAC clones revealed that the complete porcine RYR3 gene spans more than 200 kb of genomic DNA
Putting prions into focus: application of single molecule detection to the diagnosis of prion diseases
No full textPrion diseases are characterized by the cerebral deposition of an aggregated pathological isoform of the prion protein (PrPSc) which constitutes the principal component of the transmissible agent termed prion. In order to develop a highly sensitive method for the detection of PrPSc aggregates in biological samples such as cerebrospinal fluid (CSF), we used a method based on Fluorescence Correlation Spectroscopy (FCS), a technique which allows detection of single fluorescently labeled molecules in solution. Within the FCS setup, fluorescent photons emitted by molecules passing: an open volume element defined by the beam of an excitation laser focussed into a diffraction-limited spot are imaged confocally onto a single photon counting detector. Aggregates of PrPSc could be labeled by coaggregation of probe molecules such as monomeric recombinant PrP or PrP-specific antibodies tagged with a fluorescent dye. In addition to slow diffusion,? labeled aggregates are characterized by high fluorescence intensity, which allows detection and quantification by analysis of fluorescence intensity distribution. To improve detection of rare target particles, the accessible volume element was increased by scanning for intensely fluorescent targets (SIFT). To further improve sensitivity and specificity, two different probes were used simultaneously in a two-color setup. In a diagnostic model system of CSF spiked with purified prion rods, dual-color SIFT was more sensitive than Western blot analysis. In addition, a PrPSc-specific signal was also detected in a number of CSF samples derived from CJD patients but not in controls
Putting prions into focus: application of single molecule detection to the diagnosis of prion diseases
No full textPrion diseases are characterized by the cerebral deposition of an aggregated pathological isoform of the prion protein (PrPSc) which constitutes the principal component of the transmissible agent termed prion. In order to develop a highly sensitive method for the detection of PrPSc aggregates in biological samples such as cerebrospinal fluid (CSF), we used a method based on Fluorescence Correlation Spectroscopy (FCS), a technique which allows detection of single fluorescently labeled molecules in solution. Within the FCS setup, fluorescent photons emitted by molecules passing: an open volume element defined by the beam of an excitation laser focussed into a diffraction-limited spot are imaged confocally onto a single photon counting detector. Aggregates of PrPSc could be labeled by coaggregation of probe molecules such as monomeric recombinant PrP or PrP-specific antibodies tagged with a fluorescent dye. In addition to slow diffusion,? labeled aggregates are characterized by high fluorescence intensity, which allows detection and quantification by analysis of fluorescence intensity distribution. To improve detection of rare target particles, the accessible volume element was increased by scanning for intensely fluorescent targets (SIFT). To further improve sensitivity and specificity, two different probes were used simultaneously in a two-color setup. In a diagnostic model system of CSF spiked with purified prion rods, dual-color SIFT was more sensitive than Western blot analysis. In addition, a PrPSc-specific signal was also detected in a number of CSF samples derived from CJD patients but not in controls
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