1,721,044 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
Imaging Findings of Cerebral Amyloid Angiopathy, Aβ-Related Angiitis (ABRA), and Cerebral Amyloid Angiopathy-Related Inflammation: A Single-Institution 25-Year Experience
Get PDFVascular inflammation is present in a subset of patients with cerebral amyloid angiopathy (CAA) and has a major influence in determining the disease manifestations. Radiological characterization of this subset is particularly important to achieve early recognition and treatment. We conducted this study to investigate the role of imaging in differentiating CAA with and without inflammation. We reviewed neuroimaging findings for 54 patients seen at Mayo Clinic over 25 years with pathological evidence of CAA and with available neuroimaging at the time of diagnosis. Clinical data were also recorded. Patients were grouped into CAA alone (no vascular inflammation), Aβ-related angiitis or ABRA (angiodestructive inflammation), and CAA-related inflammation or CAA-RI (perivascular inflammation). Imaging findings at presentation were compared among patient subgroups. Radiological features supporting a diagnosis of ABRA or CAA-RI were identified. Radiologic findings at diagnosis were available in 27 patients with CAA without inflammation, 22 with ABRA, and 5 with CAA-RI. On MRI, leptomeningeal disease alone or with infiltrative white matter was significantly more frequent at presentation in patients with ABRA or CAA-RI compared with those with CAA (29.6% vs. 3.7%, P = 0.02; and 40.7% vs. 3.7%, P = 0.002, respectively), whereas lobar hemorrhage was more frequent in patients with CAA (62.3% vs. 7.4%, P = 0.0001). Overall, leptomeningeal involvement at presentation was present in 70.4% of patients with ABRA or CAA-RI and in only 7.4% of patients with CAA (P = 0.0001). The sensitivity and specificity of leptomeningeal enhancement to identify patients with ABRA or CAA-RI were 70.4% and 92.6%, respectively, whereas the positive likelihood ratio (LR) was 9.5. The sensitivity and specificity of intracerebral hemorrhage to identify patients with CAA were 62.9% and 92.6%, respectively, whereas the positive LR was 8.5. Microbleeds were found in 70.4% of patients with inflammatory CAA at presentation. In conclusion, leptomeningeal enhancement and lobar hemorrhage at presentation may enable differentiation between CAA with and without inflammation. The identification at initial MRI of diffuse cortical-subcortical microbleeds in elderly patients presenting with infiltrative white matter process or prominent leptomeningeal enhancement is highly suggestive of vascular inflammatory CAA
Aβ-related angiitis: comparison with CAA without inflammation and primary CNS vasculitis
No full textTo analyze the clinical findings, response to therapy, and outcomes of patients with cerebral vascular amyloid-β (Aβ) deposition with and without inflammatory vascular infiltration
Treatment of primary CNS vasculitis with rituximab: case report
No full textPrimary CNS vasculitis (PCNSV) is an uncommon disorder of unknown cause that is restricted to brain and spinal cord. Glucocorticoids alone or in combination with cyclophosphamide achieve a favorable response in most patients.(1,2) However, some patients are intolerant or respond poorly to cyclophosphamide; therefore, there is the need for new treatment options. We report a patient with PCNSV who appeared to respond to treatment with corticosteroids and rituximab. This study was approved by the Mayo Clinic Institutional Review Board and written informed patient consent to perform the study was obtained
Catastrophic primary central nervous system vasculitis
No full textPrimary central nervous system vasculitis (PCNSV) is an uncommon condition that affects the brain and the spinal cord. It is heterogeneous in presenting characteristics and outcomes. We report a patient with a catastrophic rapidly progressive course refractory to intensive treatment with pulses of methylprednisolone and iv cyclophosphamide. The condition rapidly deteriorated and the patient died 6 weeks after presentation. Rapidly progressive PCNSV represents the worst end of the clinical spectrum of PCNSV. These patients are characterised by bilateral, multiple, large cerebral vessel lesions on angiograms and multiple bilateral cerebral infarctions
Unilateral chronic relapsing primary central nervous system vasculitis
No full textWe report a case with chronic relapsing PCNSV involving only one cerebral hemisphere
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
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
- …
