1,720,996 research outputs found
Echo detected EPR as a tool for detecting radiation-induced defect signals in pottery
No full textArchaeological fragments of pottery have been investigated by using CW-EPR and Echo Detected EPR (EDEPR). EDEPR allows to remove the CW-EPR dominant Fe(III) background spectrum, hiding much weaker signals potentially useful for dating purpose. EDEPR spectra attributed to a methyl radical and to feldspar defects have been recorded at room and low temperature for an Iron Age cooking ware (700 B.C.). A study on the dependence of EDEPR intensity over absorbed dose on a series of gamma-irradiated brick samples (estimated age of 562 +/- 140 B.C.) has confirmed the potential efficacy of the proposed method for spotting defect signals out of the strong iron background. (C) 2011 Elsevier Ltd. All rights reserved
Characterization of zebrafish olig1 and olig3 genes
No full textCharacterization of zebrafish olig1 and olig3 gene
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
An TGACG motif mediates GHF1/Pit-1-dependent cAMP regulation of the rainbow trout growth hormone promoter
No full textThe mechanisms involved in the regulation of the rainbow trout growth hormone (tGH) gene promoter by the pituitary-specific transcription factor GHF1 (growth hormone factor 1), also called Pit1 (pituitary transcriptional activator 1), and cAMP have been investigated in mammalian and fish cells. The -340 to +24 5'-flanking Fegion of the tGH gene focused to the luciferase gene was activated in rat pituitary GC cells and in HeLa cells cotransfected with an effector plasmid encoding rat GHFI. GC cell nuclear extracts produced four GHFI-specific footprints (sites Fl to F4) on the tGH promoter, each containing multiple W4NCAT (W, A or T) or closely related motifs. Mutational analysis performed in GC cells indicated that the proximal Fl site alone can direct transcription, but that the region encompassing the F2 and F3 sites is necessary for optimal activation and contains a TGACG motif (cAMP-response element, CRE) conferring cAMP responsiveness. The role of the TGACG motif in mediating cAMP regulation of the tGH promoter was confirmed in primary cultures of trout pituitary cells. Cotransfection studies in carp EPC cells using an effector plasmid encoding trout GHF1 demonstrated the GHF1 dependence of cAMP stimulation. Gel shift and southwestern experiments revealed nuclear proteins of 43 kDa and 30 kDa in GC and fish cells, respectively, that bind specifically to the tGH CRE, suggesting the involvement of CRE-binding-protein/activating-transcription-factor-l-related peptides in cAMP response. Incidentally, and in contrast with previous reports, we found the rat GH promoter, that lacks TGACG motifs, unresponsive to cAMP. Thus, the CAMP stimulation of the tGH gene is more similar to its human counterpart. that is also GHF1 dependent and mediated by TGACG motifs in the promoter. It is suggested that control of GH gene expression has evolved modularly, through various assortments of the same regulatory units, rather than molecularly, through innovative units
N,O versus O,O coordination in beta-imino diketonato complexes: Role of the metal center and of the imino substituent
No full textbeta-Imino carbonyl enolato metal(II) complexes of general formula [M((RCO)(R'CO)CC(R '') NH)(2)] (M = Mn, Fe, Co, Ni, Cu, Zn, Pd, R = R' = Me, R '' = CCl(3); M = Cu, Pd, R = R' = Me, R '' = PhCO; R = Me, R' = Ph, R '' = PhCO; R = R' = Ph, R '' = PhCO) are easily synthesized by the reaction of metal(II) acetates with the proper beta-enaminodiones in 1/2 molar ratio in ethanol at room temperature. In all the cases the trifunctional NOO beta-imino carbonyl enolate ligand acts as bidentate to give ML(2) complexes, whose structure depends on the metal center and on the nature of the substituent R '' at the imino carbon. With R '' = CCl(3) an O,O coordination is observed for all the metal centers but one, in fact palladium(II) exhibits an N,O coordination through the imino nitrogen and one keto oxygen. By contrast with R '' = PhCO the ligand is always coordinated through the imino nitrogen and one keto oxygen atom
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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