1,721,204 research outputs found
Erratum to: Optical nanoscopy (La Rivista del Nuovo Cimento, (2020), 43, 8, (385-455), 10.1007/s40766-020-00008-1)
No full textAfter publication of the article we noticed that equations number 24 and 25 missed a convolution sign
A cautionary lesson from Gaia systematics: the mono-metallic globular cluster NGC 5904
Full text linkThe study of the chemistry of the stellar populations in globular clusters (GCs) is a fundamental task to unveil their formation in the high-redshift universe and to reconstruct the build-up of our Galaxy. Using metallicity estimates from BP/RP low-resolution Gaia DR3 spectra, a recent work presented the surprizing detection of two stellar populations with distinct metallicities in the stellar stream of the GC NGC 5904, otherwise considered a mono-metallic system. The presence of these two populations, with [Fe/H] ∼-1.4 and [Fe/H] ∼-2.0 dex, w as tak en as the evidence of a merger origin of the cluster. In this Letter, using the same data set complemented by new robust metallicity estimates, we carry out a detailed analysis of the metallicity distribution of stars belonging both to the cluster and to its stellar stream, explicitly focusing on the subtle effects of data systematics. We demonstrate that the population at [Fe/H] ∼-2.0 dex is a data artefact due to error systematics, affecting especially faint stars. The new higher quality metallicity sample corroborates this finding, and it indicates the presence of only one population of stars with metallicity of [Fe/H] ∼-1.3 dex, in agreement with previous literature studies. We, therefore, conclude that both NGC 5904 and its stellar stream are mono-metallic systems, and emphasize the need of carefully examining systematic effects in large and complex data
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
EFFECTS OF DIFFERENT GLYCOSAMINOGLYCANS ON MYOSIN ATPASE ACTIVITY IN PLATELETS
No full textHeparin is well known for increasing microvascular bleeding and capillary permeability [1]. Heparin also affects many functional characteristics of platelets, such as agonist-induced aggregation, piatele! adhesion [2], release of serotonin, thromboglobulin and PF4 [3]. Furthermore, heparin induces thrombocytopenia [4], prolongs thè bleeding lime in patients and has antithrombotic activity [5]
COMPETITIVE-INHIBITION OF MYOSIN ATPASE ACTIVITY BY DIFFERENT MOLECULAR-WEIGHT HEPARINS
No full textMyosin ATPase activity was measured, by continuous luminometric method, in presence of different molecular weight heparins. ATPase activity decreases in thè presence of heparin, when simultaneous incubation with ATP is carried out; thè percentage of inhibition is proportional to polysaccharide concentration. Heparins of different molecular weights (1.75 KD to 11.6 KD) are competitive inhibitors of enzymatìc activity; thè inhibitory effects is also appreciable with trisulphated disaccharide.The possible mechanisms of interactìon between heparin and myosin ATPase are discussed
Alcune considerazioni in tema di diagnosi di depressione nell'anziano e demenza tipo Alzheimer
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