1,720,957 research outputs found
Myeloproliferative disease in patients with a history of multiple blood donations: a report of 8 cases
No full textBackground. The clonal origin of myeloproliferative disorders has been clearly demonstrated and it is known that reactive thrombocytosis occurs as a non specific response to various inflammatory or neoplastic conditions. Only a few papers have discussed the topic of myeloproliferative diseases in blood donors.
Materials and Methods. We report 8 cases of myeloproliferative diseases (3 polycythemia vera and 5 essential thrombocythemia) in blood donors out of a total of 44 myeloproliferative disorders diagnosed in our Department during the last 5 years on the basis of the criteria established by the Polycythemia Vera Study Group criteria. As controls we considered 61 patients with reactive thrombocytosis referred to our Department in the same period of time. The estimated odds ratio was calculated according to standard methods.
Results. The prevalence of blood donors with myeloproliferative disorders was 18.1%, while that of donors with reative thrombocytosis was 3.2%. The estimated odds ratio was 6.56 with a 95% confidence interval between 1.07 and 17.3. No other single factor except blood donations was frequent in the past history of these patients.
Conclusions. Our data seem to indicate that both thrombocytosis and erythrocytosis resembled primary forms in these subjects; however, none of them suffered serious thrombotic and/or hemorrhagic symptoms. Our study indicates the importance of paying due attention to the blood cell counts of blood donors
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
Lower blood pressure values in blood donors?
No full text594 blood donors were studied to define the influence of regular blood donation on blood pressure. Blood pressures were compared at the first phlebotomy performed at the Padova Blood Unit, the 13-year phlebotomy, and the median between the two. As a control population, a cohort of 594 non-donors from the same general population similar to the blood donors was studied twice at a 15-year interval. Subjects had made on average 7.3 +/- 0.4 donations at the first step, 23 +/- 0.6 at the second, and 30.9 +/- 0.7 at the last step. Unadjusted systolic blood pressure regularly and significantly increased by 1.6% from the first phlebotomy to the second one and by 2.3% from the first to third. Adjusted systolic blood pressure, on the contrary, significantly decreased by 2.1% and by 2.7% respectively. Diastolic blood pressure tended to increase insignificantly, while the adjusted one did not change at all. The increase of systolic blood pressure from the first to second step directly correlated with the number of donations, and this also applied to differences between the first and the third. When the increase in age was introduced in the multiple regression analysis, systolic blood pressure rise from the first to third step showed an inverse correlation with the number of phlebotomies. Our data render suspect the results of epidemiological investigations which took into consideration cohorts of blood donors; although these cohorts may be anagraphically representative of a general population, repeated phlebotomies introduce a bias leading to the detection of misleadingly low blood pressure values in regular blood donors
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
Hemodynamics following real and hypnosis-simulated phlebotomy.
No full textForearm arterial flow was measured in 22 healthy first-time blood donors during a 300-ml. blood letting and during the subsequent recovery. Blood pressure (BP) was also taken simultaneously and forearm peripheral resistance calculated. Following a transient BP and flow increase due to tachycardia related to needle insertion, both systolic BP and flow progressively and significantly decreased, while resistance increased. In a further 22 sex- and aged-matched highly hypnotizable subjects, blood donation was simulated by means of verbal hypnotic suggestions. The BP, flow and resistance curves were similar to those obtained with the real blood letting, without any between-subject difference or group/time interaction. Mere hypnosis without suggestion of phlebotomy and the simple bed resting did not produce any effect. These results indicate that the hemodynamic changes observed during and after a blood loss are partly due to mental involvement rather than merely to the hydraulic effects of the removal of blood
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
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