1,721,133 research outputs found
HD 50844: a new look at
No full textContext.
Aims. This work presents the results obtained by CoRoT on HD 50844, the only δ Sct star observed in the CoRoT initial run (57.6 d). The aim of these CoRoT observations was to investigate and characterize for the first time the pulsational behaviour of a δ Sct star, when observed at a level of precision and with a much better duty cycle than from the ground.
Methods. The 140 016 datapoints were analysed using independent approaches
(SigSpec software and different iterative sine-wave fittings) and several checks
performed (splitting of the timeseries in different subsets, investigation of the residual light curves and spectra). A level of 10-5 mag was reached in the amplitude spectra of the CoRoT
timeseries. The space monitoring was complemented by ground-based high-resolution spectroscopy,
which allowed the mode identification of 30 terms.
Results. The frequency analysis of the CoRoT timeseries revealed hundreds of terms in
the frequency range 0–30 d-1. All the cross-checks confirmed this new result.
The initial guess that δ Sct stars have a very rich frequency content
is confirmed. The spectroscopic mode identification gives theoretical support since
very high-degree modes (up to ) are identified.
We also prove that cancellation effects are not sufficient in removing the flux variations associated to these modes at the noise level of the CoRoT measurements.
The ground-based observations indicate that HD 50844 is an evolved star that is slightly underabundant in heavy elements, located on the Terminal Age Main
Sequence. Probably due to this unfavourable evolutionary status,
no clear regular distribution is observed in the frequency set.
The predominant term ( d-1) has been identified as the fundamental radial mode
combining ground-based photometric and spectroscopic data.
Conclusions
Insight into the hormonal regulation of the epithelial calcium channels TRPV5 & TRPV6.
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50844.pdf (Publisher’s version ) (Open Access)Ca2+ plays a fundamental role in many cellular processes and its extracellular concentration is kept under strict control by the concerted actions of kidney, intestine and bone to allow proper physiological functions. The first step in active, transcellular Ca2+ transport is the influx of Ca2+ across the apical plasma membrane. Inside the cell, Ca2+ is bound to specialized proteins, called calbindins, to maintain low intracellular Ca2+ concentrations. Bound Ca2+ subsequently diffuses to the basolateral side of the cell, where it is extruded into the bloodstream via the Na+/Ca2+-exchanger (NCX1) and/or plasma membrane Ca2+-ATPase (PMCA1b). The epithelial Ca2+ channels TRPV5 and TRPV6 represent a new family of Ca2+ channels, which belong to the superfamily of transient receptor potential channels, and constitute the apical Ca2+ entry mechanism in active Ca2+ transport in kidney and intestine. The central role of TRPV5 and TRPV6 in active Ca2+ (re)absorption makes it a prime target for regulation to maintain Ca2+ balance. Therefore, the aim of this thesis was to investigate the hormonal regulation of the Ca2+ transport proteins, in particular TRPV5 and TRPV6, and provide insight into the physiological role of these Ca2+ channels and the molecular nature of Ca2+ homeostasis.RU Radboud Universiteit Nijmegen, 10 januari 2006Promotor : Bindels, R.J.M. Co-promotores : Hoenderop, J.G.J., Leeuwen, J.P.T.M. van160 p
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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