1,721,118 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
Comparison of the efficacy of two ventilatory strategies in improving arterial oxygen tension and content in anaesthetized sheep
No full textObjective: To compare F-shunt and oxygen content indices in sheep ventilated with a positive end-expiratory pressure (PEEP) of 5 cmH2O alone or preceded by a stepwise alveolar recruitment manoeuvre (ARM). Study design: Randomized crossover design. Animals: A total of six nonpregnant Brogna ewes weighing 34–47 kg, undergoing thoracolumbar magnetic resonance scan. Methods: In medetomidine-sedated sheep, anaesthesia was induced with propofol and maintained with isoflurane 1.1% ± 0.1% and an inspired oxygen fraction (FIO2) of 0.4. Animals were placed in left lateral recumbency and, after 10 minutes of spontaneous breathing, mechanically ventilated with 5 cmH2O of PEEP with (group ARM) or without (group PEEP) a stepwise recruitment manoeuvre. Maintaining a fixed driving pressure of 15 cmH2O, PEEP was increased from 0 to 20 cmH2O every 3 minutes in 5 cmH2O increments. In each sheep, arterial blood samples were collected to measure arterial gases and to calculate F-shunt, PaO2/alveolar oxygen partial pressure (PAO2) and PaO2/FIO2 during spontaneous breathing before mechanical ventilation (T0), after 20 minutes of ventilation (T20) and during spontaneous breathing at extubation (Text). Results: Both ventilatory strategies improved the arterial oxygen content although four animals in group PEEP showed oxygen content compatible with hypoxia compared with group ARM. F-shunt values were not statistically different at any time point in sheep that underwent only PEEP ventilation while they decreased at T20 and Text compared with T0 in group ARM. At extubation F-shunt was statistically lower in sheep that underwent an ARM. Mechanical ventilation improved PaO2/PAO2 and PaO2/FIO2 but they did not differ between groups. Conclusions: and clinical relevance The stepwise ARM evaluated in this study improved oxygenation indices and decreased F-shunt. This effect was maintained at extubation compared with sheep that were ventilated with only PEEP 5 cmH2O
Alveolar recruitment manoeuvre in laterally recumbent anaesthetized sheep.
Full text linkGeneral anaesthesia in laterally recumbent sheep under spontaneous ventilating may cause hypoxaemia as previously reported.
The stepwise ARM followed by mechanical ventilation with PEEP at 5 cmH2O, improves the oxygenation indices and decrease the amount of venous admixture evaluated by the F-shunt.
The positive effects of the ARM are still present in most of the animals at recovery
Sedative effects of methadone combined with medetomidine alone, or with medetomidine and vatinoxan in dogs
No full textVatinoxan, a peripheral alpha-2 antagonist, mitigates medetomidine's cardiovascular effects. This study compared sedation quality and cardiovascular variables in healthy dogs given methadone and medetomidine, with or without vatinoxan.
This study enrolled healthy dogs, undergoing elective midline ovariectomy. The animals were randomly assigned to two groups: one group received IM methadone (0.2 mg kg-1) with medetomidine (0.15 mg m-2) (group MM), and the other group received the same combination plus vatinoxan (3 mg m-2) (group MVM). Sedation was evaluated using a 21-point scale (Grint et al. 2009) at 5, 10, and 15 minutes post-administration, with scores 3 to 6 considered mild sedation. HR was measured before sedation and at 15 minutes, and systemic arterial blood pressure was measured using oscillometry. Group differences were analysed using a Student’s t-test or Wilcoxon test. A linear mixed model was used to analyse HR and MAP over time. Statistical significance was set at p < 0.05 Sixteen dogs weighing 2.5 to 46 kg were enrolled. Compared to group MM, group MVM had a statistically higher weight (p = 0.014) and body surface area (p = 0.012). Medetomidine dose was not significantly different between dogs (p = 0.760), and was 5.8 ± 3.1 and 5.5 ± 0.9 μg kg-1 in MM and MVM groups, respectively. The sedation was mild in 2 MVM dogs; the other animals were scored ≥ 8. IV catheter was inserted in all animals. HR decreased significantly (p < 0.001) in both groups, with an overall median (range) of 68 (42-100) bpm. MAP remained above 70 mmHg.
Both protocols may provide similar sedation for IV catheter insertion with cardiovascular stability. However, dogs receiving medetomidine and vatinoxan exhibited more variability in sedation compared to those receiving medetomidine alone, suggesting the need for higher doses of the combination to achieve consistent sedation levels
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
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