1,721,002 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
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
The increase in plasma matrix metalloproteinase-9 in patients with chronic urticaria is associated with disease severity but not with the presence of circulating histamine-releasing factors
No full textA number of studies have shown gender differences in the prevalence of wheeze and asthma. The aim of this review was to examine published results on gender differences in childhood and adolescent asthma incidence and prevalence, define current concepts and to identify new research needs. A Medline search was performed with the search words (gender OR sex) AND (child OR childhood OR adolescence) AND (asthma). Articles that reported on abscence or prescence of gender differences in asthma were included and reviewed, and cross-references were checked. Boys are consistently reported to have more prevalent wheeze and asthma than girls. In adolescence, the pattern changes and onset of wheeze is more prevalent in females than males. Asthma, after childhood, is more severe in females than in males, and is underdiagnosed and undertreated in female adolescents. Possible explanations for this switch around puberty in the gender susceptibility to develop asthma include hormonal changes and gender-specific differences in environmental exposures. This aspect needs consideration of the doctors and allergists who diagnose and treat asthmatic individuals. In conclusion, sex hormones are likely to play an important role in the development and outcome of the allergic immune response and asthma in particular. By obtaining functional data from appropriate models, the exact underlying mechanisms can be unravelled. To examine the effect of gender-specific differences in environmental exposures and changes of asthma prevalence and severity in puberty, larger populations may need to be investigated
Antihistamines do not inhibit the flare induced by the intradermal injection of autologous plasma in chronic urticaria patients
No full textBackground : there is some evidence suggesting that factors other than autoantibodies to FceRI or IgE and histamine released from mast cells may play a role in skin autoreactivity that characterizes many patients with chronic urticaria (CU) and, possibly, in the pathogenesis of this disease. Objective : the effect of antihistamine treatment on autologous plasma skin test (APST) in patients with CU was assessed. Methods : 24 patients with CU underwent autologous plasma skin test (APST) as well as SPT with histamine 10 mg/ml while taking antihistamines. In 6 cases the same tests had been carried out also before the start of antihistamine treatment. Plasma levels of Ddimer, prothrombin F1+2 fragment, and vascular endothelial growth factor (VEGF)
were measured in 21 patients. Results: 21/24 (87%) patients showed a large flare on APST while taking antihistamines while the skin reaction to histamine 10 mg/ml was abolished or negligible. Little difference in the autologous plasma-induced flare was seen before and after the start of cetirizine therapy in 6 cases, whereas the drug
exerted a marked effect on the histamine SPT as well as on the autologous plasma-induced
wheal. The APST-induced flare was not associated with patients’ response to antihistamine. Plasma levels of VEGF, prothrombin F 1+2 fragment, and D-dimer
were increased in plasmas from 8, 9, and 2 patients, respectively. Conclusions : factors
other than histamine are probably involved in the flare following APST in CU; such factors might play a pathogenic role particularly in patients not responding to
standard antihistamine treatment
Serum eotaxin levels in patients with chronic spontaneous urticaria
No full textEotaxin is a potent agonist for CC chemokine receptor 3 that can attract eosinophils at sites of inflammation. Given the potential role of eosinophils in chronic spontaneous urticaria (CU), we measured serum eotaxin levels together with C-reactive protein in 100 CU patients who were characterized according to autologous serum skin test (ASST) and disease severity. Serum eotaxin concentration was significantly higher in CU patients (median 140.1 pg/ml, range 33.7-718.7 pg/ml) than in 45 healthy controls (median 108.9 pg/ml, range 45.5-409.4 pg/ml) (p = 0.032) Serum eotaxin concentration was not significantly different in ASST-positive and ASST-negative patients as well as in patients with different urticaria activity scores. However, eotaxin levels tended to be higher in patients with intense symptoms. In the 7 patients observed during CU exacerbation and during remission, eotaxin serum levels tended to decrease during remission, although statistical significance was not reached (median concentration decreased from 170.0 pg/ml to 123.8 pg/ml). CRP levels were not significantly different in CU patients and healthy subjects, although there was a trend towards higher levels in the former population. Furthermore, in the 7 patients observed during CU exacerbation and during remission, CRP levels decreased significantly during remission (median concentration dropped from 4.1 microg/ml to 0.7 microg/ml, p = 0.015). No significant correlation was found between eotaxin and CRP serum levels. These findings indicate that serum eotaxin levels are increased in CU patients, although they do not reflect strictly disease activity. A role for eotaxin in eosinophil attraction and activation in CU can be envisaged
Different rates of autoreactivity in patients with recurrent idiopathic angioedema associated or not with wheals
Full text linkBACKGROUND: The pathophysiology and triggers of idiopathic nonhistaminergic angioedema are unclear. This study aimed to assess autoreactivity in recurrent idiopathic angioedema associated or not with wheals.
METHODS: The study population comprised 19 patients with recurrent idiopathic nonhistaminergic angioedema without wheals, 38 patients with angioedema and chronic urticaria (CU), and 52 patients with CU without angioedema. Twenty healthy individuals served as controls. Autoreactivity was evaluated in vivo using the autologous serum skin test (ASST) and in vitro by measuring serum-induced basophil histamine release (BHR).
RESULTS: ASST results were negative in all patients with idiopathic angioedema without wheals and in healthy controls and positive in 29 of the 38 patients with angioedema and CU (76.3%) and in 26 of the 52 patients with CU without angioedema (50%) (P < .0001 for both CU groups). BHR was negative in the healthy controls and positive in 2 of the 19 patients with idiopathic angioedema without wheals (10.5%), in 18 of the 38 patients with angioedema and CU (47.3%) (P < .0001), and in 11 of the 52 patients with CU without angioedema (21.1%) (P < .03).
CONCLUSION: The different rates of autoreactivity observed in patients with idiopathic nonhistaminergic angioedema without wheals and in patients with CU either with or without angioedema suggest that these disorders have a different pathophysiology. The failure to detect circulating vasoactive factors and histamine-releasing autoantibodies explains why H1 antihistamines are scarcely effective in most patients with idiopathic angioedema without wheals. However, they represent the cornerstone of CU treatmen
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