1,721,030 research outputs found
Evaluation of anisotropic correction factors for the calculation of Landsat 8 OLI albedo on the ice sheets = Evaluation of anisotropic correction factors for the calculation of Landsat 8 OLI albedo on the ice sheets.
No full textThe calculation of ice and snow albedo on the ice sheets from re-mote sensing has always been an important objective in climate research, especially at a high spatial resolution. In this study, a model of albedo retrieval based on Landsat 8 OLI satellite data is validated by comparing ground observations from Antarctica and Greenland, with a particular focus on the anisotropic correction of satellite data. Different correction factors for the anisotropy of snow and ice were considered, as well as two different conversion formulas from narrowband to broadband albedo. Our findings point out that existing anisotropic-correction models are unable to adequately account for albedo variations at high solar zenith angles, which is a relevant factor in Greenland and especially in Antarc-tica. Thus, the present study suggests that the anisotropic correction may be omitted when calculating ice and snow albedo on the ice sheets, as on average worse statistics were found when using the correction
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
Feasibility and challenges of independent research on drugs : the Italian medicines agency (AIFA) experience
No full textKey points : National Health Service (NHS) is becoming increasingly aware of the need to support independent research to answer some important questions for patient care in areas of scant commercial interest. * This article reports the main features and strategies of the independent research programme on drugs launched by the Italian Medicines Agency (AIFA) in 2005. * In the three bids launched between 2005 and 2007, a total of 151 studies have been approved for funding for a total of about 78 million Euro. * In this article we describe the Italian legislative framework under which the programme was launched, the types of research funded and discuss how the supported studies could contribute, in an international framework, to the knowledge needed on drug efficacy, effectiveness and safety
Preliminary results from antarctic albedo from remote sensing observations
Full text linkThe aim of the study is to analyse the surface albedo of the Ant-arctica and investigate eventual signals of variations in space and time between summer 2000/2001 and 2011/2012 by means of the GLASS albedo product. We followed a step-by-step procedure from micro- to macro-scale. At first, we analysed 95 glaciers around the continent, and we found limited temporal variability. Then, looking at spatial varia-tions, we divided Antarctica based on oceanic basins and by continen-tality. We found spatial signals, since mean albedo values range between 0.79 (Pacific and Atlantic basins) and 0.82 (Indian basin) and between 0.76 (along the shore) and 0.81 (inner continent). An increasing vari-ability was found from the inner continent to the shore, and heteroge-neous patterns among the basins, most likely due to meteorological and environmental conditions (mainly: temperature, precipitation, katabatic winds). Finally, the general patterns observed (considering the specific gla-ciers, the three basins and the three continentality sectors) were verified by the analysis of the whole continent and we did not find a significant change of summer averages over time, as they range between 0.79 and 0.80
Behavior of aqueous-nanocrystalline-hydroxyapatite in oral bone regeneration
No full textABSTRACTPurpose: A skeletal segment consisting exclusively of bone is the target outcome of bone regeneration. Granular hydroxyapatitesform a hydroxyapatite-bone composite, unsuitable for effectively supporting implants, which may persist for manyyears. This work aimed to investigate the reasons for the bone replacement of Ostim®, a recently commercialized aqueousnanocrystalline hydroxyapatite.Methods: Histology, SEM and X-ray microanalysis were employed to analyze 6- to 9-month biopsies of post-extractive sitesor sinus floor lifts of the maxilla in 15 subjects.Results: The results highlight a great bone formation, Ostim® resorption with time by osteoclasts but also interstitial fluid propagationof Ostim® masses by percolation. A possible osteocyte protoplasmic involvement was also at work in concert to reach the target.Conclusions: The use of Ostim® as bone regenerating material leads to the formation of a highly suitable implant supportconsisting exclusively of bone in less than 12 months, i.e. in a remarkably short time
Hematemesis from esophageal varices associated with esophageal perforation: sclerotherapy and endoscopic clipping.
No full textA 46-year-old man was referred to our Unit for hematemesis. The medical history of the patient revealed an HCV-related cirrhosis, a human immunodeficiency virus (HIV) infection and recent and persistent episodes of emesis. An urgent gastroscopy disclosed evidence of active bleeding from varices of the lower third of the esophagus and a concomitant laceration of the esophageal wall due to the emesis. These two conditions have been endoscopically diagnosed and successfully treated by sclerotherapy and endoscopic clipping.esophagA 46-year-old man was referred
to our Unit for hematemesis. The medical history
of the patient revealed an HCV-related cirrhosis, a
human immunodeficiency virus (HIV) infection
and recent and persistent episodes of emesis. An
urgent gastroscopy disclosed evidence of active
bleeding from varices of the lower third of the
esophagus and a concomitant laceration of the
esophageal wall due to the emesis. These two
conditions have been endoscopically diagnosed
and successfully treated by sclerotherapy and
endoscopic clipping
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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