1,721,081 research outputs found
Hund's coupling and the metal-insulator transition in the two-band Hubbard model
No full textThe Mott-Hubbard metal-insulator transition is investigated in a two-band
Hubbard model within dynamical mean-field theory. To this end, we use a
suitable extension of Wilson's numerical renormalization group for the
solution of the effective two-band single-impurity Anderson model. This
method is non-perturbative and, in particular, allows to take into
account the full exchange part of the Hund's rule coupling between the
two orbitals. We discuss in detail the influence of the various
Coulomb interactions on thermodynamic and dynamic properties, for both
the impurity and the lattice model. The exchange part of the
Hund's rule coupling turns out to play an important role for the physics
of the two-band Hubbard model and for the nature of the Mott-transition
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
Analysis of anti-C1q antibodies in normal and pathological pregnancies
No full textAnalysis of anti-C1q antibodies in normal and pathological pregnancies
C. Agostinis1, A. Mangogna2, O. Radillo1, G. Ricci1, R. Bulla2.
1. Institute for Maternal and Child Health, IRCCS Burlo Garofolo, 34137, Trieste, Italy;
2. Department of Life Sciences, University of Trieste, 34127, Trieste, Italy.
PROBLEM
C1q, the recognition molecule of the classical pathway of the complement system plays foundamental roles in pregnancy. C1q has been shown to promote trophoblast endovascular and interstitial invasion and is involved in the clearance of immune complexes and apoptotic bodies. Lack of C1q is characterized by poor trophoblast invasion and pregnancy failure.
This molecule can be also the target of an antibody response: anti‐C1q antibodies are present in several infectious and autoimmune diseases. The presence of these auto-antibodies has been detected also in 2 to 8% of the general population.
The aim of this study was to evaluate the presence and the circulating levels of anti-C1q Ab in pre-eclamptic (PE) patients compared to healthy pregnant women.
METHOD
Levels of anti‐C1q antibodies were analyzed by ELISA in PE and control sera obtained in the first and third trimester of pregnancy.
RESULTS
Anti-C1q antibodies were detected in both normal and PE sera. Higher levels of these antibodies were present in the first trimester compared to term normal pregnant sera. Early onset PE patients showed higher levels of anti-C1q antibodies compared to late onset PE patients.
CONCLUSION
Anti-C1q antibody levels increased during the first trimester of pregnancy. The level of these antibodies was higher in the sera of some early onset PE patients. These data indicates a possible role of anti-C1q antibodies in the control of pregnancy and in the pathogenesis of PE. The role played by these antibodies at foeto-maternal interface requires further investigation
Human eosinophil peroxidase enhances TNF and hydrogen peroxide release by human monocyte-derived macrophages
No full textOverview of procalcitonin in pregnancy and in pre-eclampsia
No full textProcalcitonin (PCT), a precursor for calcitonin, is a prohormone involved in the inflammatory processes, which has been poorly studied in the context of pregnancy. During severe inflammation, PCT derives from almost all cell types, including monocytes and parenchymal tissues, making it a good predictive and diagnostic marker of an inflammatory state with rapidly increased serum levels in inflammation or sepsis. In normal pregnancy, PCT is basally expressed at very low level by decidual cells, even if decidual macrophages, which in normal pregnancy are skewed to M2 macrophages, are resistant to lipopolysaccharide (LPS)-induced production of PCT. As PCT increase is associated with an inflammatory state, several research groups investigated whether PCT can be considered a marker of pre-eclampsia, a pregnancy disease characterized by systemic inflammation. The first aim of this review is to summarize what is already known about the tissues synthesizing PCT, about the stimuli that cause the increase of circulating PCT levels and how PCT acts as a proinflammatory stimulus by itself. Secondly, we will describe the role of this prohormone in normal pregnancy and in pregnancies complicated by pre-eclampsia, highlighting the involvement of the decidual macrophages and the proinflammatory cytokine tumor necrosis factor-α in the modulation of PCT expression in the decidual microenvironment
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
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