1,721,057 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
Brain microbleeds 12 Years after orthotopic liver transplantation in Val30Met amyloidosis
No full textUnexplained focal neurologic episodes (FNEs) can occur in patients with transthyretin-related familial amyloidotic polyneuropathy (TTR-FAP) after orthotopic liver transplantation (OLT). A patient with Val30Met FAP underwent OLT at age 34 years. Twelve years after transplantation, she presented with recurrent FNEs lasting from 10 minutes to 8 hours each, with nonuniform deficitary clinical features and variably associated with headache. Magnetic resonance imaging showed multiple brain microbleeds and diffuse contrast enhancement of the craniospinal leptomeninges consistent with amyloid deposits. Our observation suggests that microbleeds associated with meningovascular amyloidosis can underlie FNEs in TTR-FAP. Moreover, it confirms that OLT does not halt progression of leptomeningeal and vascular amyloid deposition due to TTR production in the choroid plexuses. Such a progression might compromise the good long-term prognosis of patients with TTR-FAP due to increased risk of intracranial hemorrhages. Pharmacologic therapies targeting brain TTR production may modify this scenario
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
Fixing the jugular flow reduces ventricle volume and improves brain perfusion
No full textObjective Increased ventricle volume and brain hypoperfusion are linked to neurodegeneration. We hypothesized that in patients with restricted jugular flow, surgical restoration may reduce brain ventricle volume, because it should improve the pressure gradient, hence promoting cerebrospinal fluid reabsorption into the venous system. Methods The effects of restoring the jugular flow were assessed by means of a validated echocardiography with color Doppler (ECD) protocol of flow quantification, magnetic resonance venography, and single-photon emission computed tomography combined with computed tomography (SPECT-CT). The main outcome measurement was the cerebral ventricle volume blindly assessed at SPECT-CT. Secondary outcomes were brain perfusion in the whole brain and in another 12 cerebral regions. The mean follow-up of the SPECT-CT and ECD parameters was 30 days. Patency rate was subsequently monitored by means of the same ECD protocol every 3 months. Results Among 56 patients (28 male and 28 female; mean age, 44 ± 10 years) with ECD screening positive for chronic cerebrospinal venous insufficiency due to nonmobile jugular leaflets, 15 patients were excluded from the initial cohort because they did not meet the inclusion and exclusion criteria. Of the remaining 41 patients, 27 patients (14 male, 13 female; mean age, 48 ± 7 years) underwent endophlebectomy and autologous vein patch angioplasty. Omohyoid muscle section was performed when appropriate. The control group comprised 14 patients matched by age and gender (8 male, 6 female; mean age, 44 ± 11 years) who were not treated. Comorbidity was multiple sclerosis without significant differences in relapsing remitting (RR) and secondary progressive (SP) clinical course among groups. In the control group, neither ECD nor SPECT-CT showed any significant changes at follow-up. On the contrary, in the group operated on, the collateral flow index went from 70% to 30% (P <.0003) thanks to improved flow through the internal jugular vein. Correspondingly, ventricle volume dramatically decreased in the treated group (from 34 ± 14 cm3 to 31 ± 13 cm3; P <.01). The effect was much more evident in the RR subgroup (P =.009), whereas in the SP subgroup, it was not significant. Perfusion was found to be improved in the surgical group with respect to controls, particularly in the occipital and parietal regions of the RR subgroup (P <.0001 and P =.017, respectively), but not in the SP subgroup. The probability of reducing ventricle size is increased by 13-fold (P <.03) when restoration of the jugular flow achieves a postoperative collateral flow index ≤20%. Finally, the 18-month patency rate was 74%. Conclusions Fixing the flow in the jugulars in patients with chronic cerebrospinal venous insufficiency might significantly reduce brain ventricle volume and improve cerebral perfusion. These changes are more evident in patients in the earlier stages of neurodegenerative disease
Prevalence and Psychopathological Determinants of Sexual Dysfunction and Related Distress in Women With and Without Multiple Sclerosis
No full textIntroduction:Sexual dysfunction (SD) is common but still underdiagnosed in women with multiple sclerosis(MS); in fact, the lack of a consistent use of validated diagnostic tools makes the prevalence of SD and relateddistress difficult to define precisely.Aim:To assess the prevalence of SD in Italian women with MS compared with age-matched healthy controlsubjects (HC) and the association with demographic, psychological, and MS-related characteristics.Methods:The Female Sexual Function Index (FSFI) and the Female Sexual Distress Scale were administered to153 women with MS and 153 HC. Demographic, gynecologic, and neurologic data were obtained. Disabilitywas assessed using the Expanded Disability Status Scale. Psychological symptoms were evaluated in MS patientswith Profile of Mood State and the Beck Depression Inventory II.Main Outcomes Measures:Prevalence of SD and sexual distress in women with MS compared with HC.Results:Among women sexually active in the last month, we found an increased prevalence of SD in MS patientscompared with HC subjects (42.0% vs 16.0%,P1⁄4.0001). The prevalence of dysfunctional FSFI global scores(<26.55) was higher in women with MS compared with HC (49.6% vs 33.6%,P1⁄4.014). In the MS group, theprevalence of SD was similar between pre- and post-menopausal women. Both premenopausal and postmenopausalMS women presented a greater prevalence of SD if compared with the premenopausal and postmenopausal HCgroups (30/79 [37.9%] vs. 5/74 [6.8%],P1⁄4.0001 and 20/40 [50.0%] vs 16/57 [28.1%],P1⁄4.03, respectively). Anegative correlation was observed between the FSFI global score and age and Expanded Disability Status Scale.Depressive symptoms were more common in women with MS and SD than in those without.Clinical Implications:This study suggests that sexual function investigation should always be a standard part ofthe consultation with healthcare professionals for MS.Strength & Limitations:The strength of this study was the comparison with an age-matched healthy controlgroup and the use of validated questionnaires to assess both sexual function and sexual distress. Larger andmulticenter studies may further support ourfindings.Conclusion:In our cohort, the prevalence of SD and sexual distress was higher in women with MS compared tothe HC group. Age, disability, and depressive symptoms were associated with increased SD
Long-term influence of combined oral contraceptive use on the clinical course of relapsing-remitting multiple sclerosis
No full textOBJECTIVE:
To assess the long-term effects of combined oral contraceptives (COCs) on the clinical course of relapsing-remitting multiple sclerosis (RRMS), focusing on disability progression and evolution to secondary-progressive multiple sclerosis (SPMS).
DESIGN:
Retrospective and exploratory study.
SETTING:
Academic medical center.
PATIENT(S):
A total of 174 women with clinically confirmed MS; of these, 33 had evolved to SPMS at the time of enrollment in the study, whereas 141 still had a relapsing-remitting form of disease.
INTERVENTION(S):
Women were interviewed to obtain gynecologic and obstetric history.
MAIN OUTCOME MEASURE(S):
Expanded Disability Status Scale (EDSS); Multiple Sclerosis Severity Score (MSSS); annualized relapse rate; evolution to SPMS.
RESULT(S):
Mean±SD duration of disease was 14.3±9.8 years. Compared with non-users of COCs, COC users had lower EDSS scores and MSSS only in the subset of the population with prior or current immunomodulatory treatment. Nonuse of COCs was a predictor of disease evolution in SPMS, whether treated or not with immunomodulatory drugs. The annualized relapse rate was not influenced by COC use. No differences in EDSS scores and evolution to SPMS depending on COC formulation were detected.
CONCLUSION(S):
Our results suggest that COC use is associated with a less severe disease and less severe evolution. Whether different doses or types of progestin may have different effects remains to be defined
- …
