1,721,008 research outputs found
In situ high temperature single crystal X-ray diffraction study of a natural omphacite
No full textIn situ high temperature single crystal X-ray diffraction (XRD) experiments have been performed on a chemically quasi-ideal omphacite sample [(Ca0.49Na0.51)(Σ1)(Mg0.46Al0.48Fe0.063+)(Σ1)(Si1.97 Al0.03)(Σ2)O6], up to 1000°C. The lattice parameters were studied as a function of temperature, and their thermal expansion coefficients determined. The b and c cell edges show discontinuities as a function of temperature which are interpreted here in terms of intracrystalline cation diffusion processes. Structure refinements have been carried out using data collected at room temperature, at 800°C and at ambient conditions after cooling. The structural behaviour as a function of temperature of chemically quasi-ideal omphacites is compared with those of jadeite and diopside
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
The relevance of hemoglobin F measurement in the diagnosis of thalassemias and related hemoglobinopathies
No full textObjectives: The increase in hemoglobin (Hb) F level is variably associated to the presence of beta thalassemia trait, and is more typical in presence of δβ thalassemia and of hereditary persistence of fetal hemoglobin. In normal healthy subjects variable levels of HbF are related to the presence of the polymorphism Gγ - 158 (C > T). Moreover, HbF can also be variably increased in association with other acquired conditions. The objective of this work is to review the role of the determination of HbF in various conditions. Design and methods: In the present document we comment on the need for accuracy and standardization, and on the interpretation of the HbF value, reviewing most crucial aspects related to this test. Results: We present a practical flow-chart summarizing the significance of the HbF estimation in different thalassemia syndromes and related hemoglobinopathies. Conclusion: The determination of HbF is relevant for the final diagnosis of various physiopathological conditions. In our opinion its importance will increase in the following years, because of the proliferation of novel approaches for the induction of HbF synthesis as a cure for thalassemia syndromes
Valutazione multicentrica dell'analizzatore Tosoh G8 per la misura dell'emoglobina A2 e dell'emoglobina F
No full textThe analytical performance of the new Tosoh automated analyzer HLC-723 G8 (-thalassemia analysis mode) to determine hemoglobin variants and to measure HbA2 and HbF in human blood was evaluated in three Italian centres. The within- and between-run imprecision for HbA2 were good, with CV between 0.2% and 1.8% and between 0.9% and 5.4%, respectively. The CV for HbF was between 0.4% and 9.8% (within-run) and beetwen 0.8% and 13.1% (between-run). The comparability of HbA2 measurements between different centres was excellent (r=0.99), but a significant bias in comparison with the previous version of the instrument was noted. Experiments to test the HbA2 stability in blood confirmed that blood samples stored at -80 C were stable for at least 4 months and that storage at -20 C is not recommended. In conclusion, the Tosoh G8 analyser was found reliable and robust and, therefore, suitable for the measurement of HbA2 and HbF in human blood
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
Anemia a cellule falciformi e sindromi correlate: aggiornamenti e prospettive
Full text linkThe presence of hemoglobin S (HbS) in blood is responsible for sickle cell disease when its concentration, for the presence of two copies of HbS gene or one copy of HbS plus another β-globin variant (such as hemoglobin C or β-thalassemia), is markedly increased. In this report, we reviewed some recent epidemiological data on the disease prevalence, we discussed pre-analytical as well analytical aspects, relevant to the correct measurement of HbS in blood, and we summarized some important aspects for the management of the sickling crises and for the current and future therapy of this disease
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
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