1,720,959 research outputs found

    Clinical and cognitive outcome after surgical resection of cerebral AVMs in language areas

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    Background: The management cerebral AVMs is not always clear - especially if located in eloquent areas - and could range between observation and microsurgical resection. Surgery is highly demanding and can be associated with post-operative neurological sequelae. The present study aims to analyze how natural history and clinical-radiological features impact the clinical and cognitive outcome after surgery for cerebral arteriovenous malformations (AVMs) located in language areas. Methods: A retrospective cohort study was conducted on a continuous series of 311 patients operated on for cerebral AVMs at a single institution by a single neurosurgeon between 1990 and 2020. Speech areas were classified in 4 regions: frontal operculum, inferior parietal lobule, superior temporal gyrus, and sylvian-insular. Post-operative deficits were classified as transient and permanent; the latter were further divided into mild (modified Rankin score ≤2) and significant (mRS ≥ 3). A post-operative neuropsychological evaluation was conducted at follow-up to assess long-term cognitive deficits. Results: A total of 63 patients were considered eligible; the AVM was located in the frontal operculum in 20 cases, in the inferior parietal lobule in 8 cases, in the superior temporal gyrus in 27 cases and in the sylvian-insular region in 8 cases. The ruptured and unruptured AVMs ratio was 1:1.1. Patients with bleeding AVMs showed preexisting neurological deficit as a determining factor for post-operative morbidity, regardless of the AVM volume. Post-operative deficits in unruptured AVMs were mostly transient (63.6 %); a significant deficit was present in 1 case with AVM volume >20 cm3. Neuropsychological deficits were higher in ruptured and in large volumes (>20 cm3) AVMs cases. Conclusions: Surgical management of cerebral AVMs in speech areas is safe, especially for smaller AVMs (<20 cm3). In ruptured AVMs the clinical outcome is influenced mostly by the hemorrhage, whereas unruptured AVMs showed mild neurological sequelae

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

    Surgical treatment of anterior cranial fossa dural arterio-venous fistulas (DAVFs): a two-centre experience

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    Anterior cranial fossa dural arterio-venous fistulas (DAVFs) represent 6% of all intracranial DAVFs; characteristically they show an aggressive behaviour with high risk of intracranial haemorrhage. Peculiar anatomical features, such as feeding by the ethmoidal arteries and the pattern of venous drainage (frequently with varices that mimic aneurysmal dilatation), can be evaluated in detail only by digital subtraction angiography (DSA), which represents the "gold standard" in the diagnosis of such cranial fistulas. Recent technological developments in endovascular management of this type of DAVF have partially reduced the morbidity risk related to this modality of treatment. Our purpose is to present our experience in the surgical management of 14 patients with anterior cranial fossa DAVFs, with attention paid to the possible role of preoperative embolisation in these cases and to the surgical technique.Between 1999 and 2015, 14 patients with anterior cranial fossa DAVFs were submitted to surgery in two neurosurgical departments; the mean age was 63 years old; nine DAVFs caused intracranial haemorrhage (subarachnoid haemorrhage in three cases, intracerebral haemorrhage in six cases). Pre-operative embolisation was attempted in an early case and was successfully done in one recent case. In all patients, the surgical approach chosen was a pterional craniotomy with a low margin on the frontal bone in order to gain the exposure of the anterior cranial fossa and especially of the olphactory groove region; the resection of the falx at its insertion on the crista galli was needed in five cases in order to get access to the contralateral afferent vessels. Cauterisation of all the dural feeders on and around the lamina cribrosa was needed in all cases; venous dilatations were evident in eight patients (in seven out of nine patients with ruptured DAVF and in one out of five patients with unruptured DAVF) and were removed in all cases. One patient harboured an ophthalmic artery aneurysm, which was excluded by clipping.One patient died 5 days after surgery due to the severity of the pre-operative haemorrhage. Postoperative DSA showed the disappearance of the DAVF and of the venous pseudo-aneurysms in all cases. Clinical outcome was favourable (without neurological deficits) in 11 patients; three patients presented an unfavourable clinical outcome, due to the severity of the initial haemorrhage.Surgical exclusion of the anterior cranial fossa DAVFs still represents the gold standard for such lesions, due to low post-operative morbidity and to complete protection against future rebleedings; endovascular techniques may help the surgeon in complex cases

    Dispelling the Myths Behind First-author Citation Counts

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    We 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

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We 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
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