1,721,045 research outputs found
Inner ear connexins, intercellular signalling and deafness.
No full textThe genes GJB2 and GJB6 respectively encoding transmembrane proteins connexin 26 (C×26) and connexin 30 (C×30) are found within 50 kb of each other in the DFNB1 complex deafness locus on chromosome 13ql2. Up to 50% of all patients with autosomal recessive non-syndromic prelingual deafness in different populations present with mutations or deletions in this locus. C×26 and C×30 are abundantly expressed in the inner ear and, in recent years, have been shown to form hemichannels that release ATP from the endolymphatic surface of supporting and epithelial cells of the organ of Corti (OoC), as well as gap junction (GJ) channels that allow the concomitant intercellular diffusion of Ca2+ mobilizing second messengers. Released ATP in turn activates G-protein coupled P2Y2 and P2Y4 receptors, PLC-dependent generation of IP3, release of Ca2+ from intracellular stores, ensuing in the regenerative propagation of intercellular Ca2+ signals (ICS) across these coupled cells. The range of ICS propagation in the OoC is sensitive to the concentration of extracellular divalent cations and to ectonucleotidase activity. Strictly related oscillations of the intracellular free Ca2+ concentration ([Ca2+]i) in cochlear supporting cells are also evoked by nanomolar concentrations of ATP on the endolymphatic surface of the OoC. ICS and [Ca2+]i oscillations are of great interest in relation to the responses evoked by damaging stimuli delivered to hair cells, and may play a crucial role in development of the OoC and the acquisition of hearing
Entanglement of Identical Particles and Reference Phase Uncertainty.
No full textWe have recently introduced a measure of the bipartite entanglement of identical particles, EP, based on the principle that entanglement should be accessible for use as a resource in quantum information processing. We show here that particle entanglement is limited by the lack of a reference phase shared by the two parties, and that the entanglement is constrained to reference-phase invariant subspaces. The super-additivity of EP results from the fact that this constraint is weaker for combined systems. A shared reference phase can only be established by transferring particles between the parties, that is, with additional nonlocal resources. We show how this nonlocal operation can increase the particle entanglement.Full Tex
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
Symmetry-adapted representation learning
No full textIn this paper, we propose the use of data symmetries, in the sense of equivalences under signal transformations, as priors for learning symmetry-adapted data representations, i.e., representations that are equivariant to these transformations. We rely on a group-theoretic definition of equivariance and provide conditions for enforcing a learned representation, for example the weights in a neural network layer or the atoms in a dictionary, to have the structure of a group and specifically the group structure in the distribution of the input. By reducing the analysis of generic group symmetries to permutation symmetries, we devise a regularization scheme for representation learning algorithm, using an unlabeled training set. The proposed regularization is aimed to be a conceptual, theoretical and computational proof of concept for symmetry-adapted representation learning, where the learned data representations are equivariant or invariant to transformations, without explicit knowledge of the underlying symmetries in the data
Left ventricular hypertrophy in athletes: How to differentiate between hypertensive heart disease and athlete’s heart
No full textAthlete’s heart is typically accompanied by a remodelling of the cardiac chambers induced by exercise. However, although competitive athletes are commonly considered healthy, they can be affected by cardiac disorders characterised by an increase in left ventricular mass and wall thickness, such as hypertension. Unfortunately, training-induced increase in left ventricular mass, wall thickness, and atrial and ventricular dilatation observed in competitive athletes may mimic the pathological remodelling of pathological hypertrophy. As a consequence, distinguishing between athlete’s heart and hypertension can sometimes be challenging. The present review aimed to focus on the differential diagnosis between hypertensive heart disease and athlete’s heart, providing clinical information useful to distinguish between physiological and pathological remodelling
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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