1,720,970 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
Lack of improvement in cerebral metabolism after hyperoxia in severe head injury: A microdialysis study
No full textObject. The authors investigated the effects of hyperoxia on brain tissue PO2 and on glucose metabolism in cerebral and adipose tissue after traumatic brain injury (TBI). Methods. After 3 hours of ventilation with pure O2, 18 tests were performed on different days in eight comatose patients with TBI. Lactate, pyruvate, glucose, glutamate, and brain tissue PO2 were measured in the cerebral extracellular fluid (ECF) by using microdialysis. Analytes were also measured in the ECF of abdominal adipose tissue. After 3 hours of increase in the fraction of inspired O2, brain tissue PO2 rose from the baseline value of 32.7 ± 18 to 122.6 ± 45.2 mm Hg (p < 0.0001), whereas brain lactate dropped from its baseline (3.21 ± 2.77 mmol/L), reaching its lowest value (2.90 ± 2.58 mmol/L) after 3 hours of hyperoxia (p < 0.01). Pyruvate dropped as well, from 153 ± 56 to 141 ± 56 μmol/L (p < 0.05), so the lactate/pyruvate ratio did not change. No significant changes were observed in glucose and glutamate. The arteriovenous difference in O2 content dropped, although not significantly, from a baseline of 4.52 ± 1.22 to 4.15 ± 0.76 ml/100 ml. The mean concentration of lactate in adipose tissue fell significantly as well (p < 0.01), but the lactate/pyruvate ratio did not change. Conclusions. Hyperoxia slightly reduced lactate levels in brain tissue after TBI. The estimated redox status of the cells, however, did not change and cerebral O2 extraction seemed to be reduced. These data indicate that oxidation of glucose was not improved by hyperoxia in cerebral and adipose tissue, and might even be impaired
Hypothermia for brain protection in the non-cardiac arrest patient
No full textThis review focuses on the potential application of hypothermia in adults suffering traumatic brain injury (TBI). Hypothermia is neuroprotective, reducing the damaging effects of trauma to the brain in a variety of experimental situations, such as brain ischemia and brain injury, but it has failed to demonstrate outcome improvement in a major controlled, randomized trial. The evidence for the use of hypothermia as a protective procedure is scarce and contradictory. However, evidence does suggest that hypothermia is effective in reducing intracranial hypertension after head injury. Since hypothermia has important side effects, further work is necessary before introducing this procedure into clinical practice for TBI
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
Analysis of propofol/remifentanil infusion protocol for tumor surgery with intraoperative brain mapping
No full textBACKGROUND: There is no general consensus about the best anesthesiologic approach to use during craniotomies with intraoperative brain mapping, and large prospective studies evaluating the complications associated with different approaches are lacking. Objective of this study was to prospectively collect and evaluate data about a large series of consecutive asleep-awake and asleep-asleep craniotomies. METHODS: We analyzed 238 consecutive procedures from January 2005 to December 2008. During asleep-awake procedures, patients were initially ventilated through a laryngeal mask which was removed to allow language testing. During asleep-asleep procedures, patients remained sedated and intubated to permit motor testing. RESULTS: In asleep-awake craniotomies [n = 135, age 42y (range: 16 to 72y), American Society of Anesthologists classification (ASA) 1 (1 to 3), and body mass index 24.2 ± 3.7 kg/m 2], 43% of the procedures were free of complications. Most common complications were hypertension (27%) and brief clinical seizures (16%), but also hypotension (10%), vomiting (7%), brief periods of apnea (4%), and agitation (6%) were observed. In 7% of the procedures, seizures required pharmacologic treatment. Fifty-nine percent of the asleep-asleep procedures [n=103, age 51y (range: 21 to 76y), ASA 1 (1 to 3), body mass index 25.4 ± 3.9kg/m2, P < 0.05 vs. asleep-awake] were free of complications. Clinical seizures were observed in 31% of the cases. The administration of boluses of hypnotics was rarely necessary (6%) and safer because of secured airways. CONCLUSIONS: With this study, we demonstrated the feasibility and safety of our protocols on large prospective case series. Asleep-awake protocol can be safely used when intraoperative language mapping is planned, whereas an asleep-asleep protocol with secured airway might be preferred when motor testing only is required. Copyright © 2010 by Lippincott Williams & Wilkins
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
Distinction between fetal growth restriction and small for gestational age newborn weight enhances the prognostic value of low PAPP-A in the first trimester
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Prevalence and type distribution of high-risk human papillomavirus infection in women undergoing voluntary cervical cancer screening in Italy
No full textThe aim of this survey was to assess the prevalence and distribution of oncogenic human papillomavirus (HPV) genotypes in women who underwent screening for cervical cancer in Italy. The correlation of genotypes with the cytological results was also evaluated. Cervical samples were collected from 9,947 self-referring women for cervical cancer screening. Participants were screened by liquid-based cytology and high-risk HPV testing using the Hybrid Capture 2 test. Positive samples were genotyped by PCR. Samples (1,474; 14.8%) were positive for high-risk HPV. The prevalence was 29.4% in the 15-19 years-group, decreasing progressively to 6.1% at 50-54 years of age and increasing to 12.2% in those aged over 65 years. HPV 16 was the genotype detected most frequently followed by HPV 31, HPV 18, HPV 56, and HPV 51. HPV 16 or 18 were present in 4% of women with normal cytology and both were detected contemporarily in only 14 women. Twenty-two percent of atypical squamous cells, 26% of low-grade and 56% of high-grade squamous intraepithelial lesions at cytology were positive for HPV 16 and/or 18. The prevalence of HPV infection in Italy is in agreement with that reported worldwide. HPV 16 was the prevalent genotype. The concomitant infection with HPV 16 and HPV 18 (vaccine targets) was found rarely. Apart from HPV 16 and 18, there was a substantial presence of HPV genotypes against which the vaccines available currently have shown cross-protection efficacy. The findings of this study may contribute to reliable predictions on the potential efficacy of an HPV vaccine in clinical practice. J. Med. Virol. 81:529-535, 2009. (C) 2009 Wiley-Liss, Inc
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