1,721,031 research outputs found
Is the diagonal case a general picture for Loop Quantum Cosmology?
Full text linkThe correct implementation of the Loop Quantum Gravity to the early
homogeneous Universe has been the subject of a long debate in the literature
because the SU(2) symmetry cannot be properly retained. The role of this
symmetry is expressed by the Gauss constraint. Here, a non-vanishing Gauss
constraint is found. However, we show that using suitable variables, it can be
recast into three Abelian constraints, justifying the absence of such a
symmetry in Loop Quantum Cosmology.Comment: 6 page
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
New PMMA bone cement added with ferrimagnetic bioactive glass for hyperthermia treatment
No full textINTRODUCTION
The design of a composite material like Polymethylmethacrylate (PMMA) bone cement loaded with a bioactive and ferrimagnetic glass-ceramic is very useful against the development and proliferation of bone tumors. This biomaterial produces heat by magnetic hysteresis loss due to presence of magnetite (Fe3O4) inside the glass-ceramic phase1 and so it can be used in hyperthermia treatment. Moreover, the bioactive component of the glass-ceramic confers osteointegration property at the material. The aim of the present work is the synthesis and characterization of a composite cement in which the disperse phase is a glass ceramic (SC45) with magnetic property, embedded in a polymeric (PMMA) matrix.
EXPERIMENTAL METHODS
The SC45 powders, (see1 for the chemical composition) sieved below 20 micron, were mixed in different amounts (10, 15, 20% wt) with the polymeric solid phase of a commercial bone cement (Palamed®MV). The mixed powders and the liquid monomer were manually mixed for two minutes and subsequently put inside a mold, obtaining the composite cements. P10, P15, P20. Furthermore commercial cements were prepared as control. The characterizations were developed for all formulations proposed as described below.
Mechanical testing of cement samples
The compressive strength of the cement were evaluated according to standard ISO 5833 procedure. For each formulation 6 samples were tested.
Calorimetric measurements
The heat generation was measured with an induction furnace at fixed frequency and alternate electromagnetic field. The samples were placed in a test tube containing 10 ml of distilled water. The increase of temperature that occurred following the heat transfer from the magnetic phase of the composite to water was measured with a thermocouple.
SEM and EDS analysis before and after bioactivity test
SEM-EDS analyses were carried out to evaluate the morphology and composition of the samples.
RESULTS AND DISCUSSION
The compression strength of the composites depends from the amount of glass-ceramic phase; nevertheless the reached values satisfy the ISO requirements ( >70 MPa).
Calorimetric tests show a maximum increasing temperature of 40°C that respect the limit imposed by hyperthermia therapy.
CONCLUSION
The preliminary experimental tests demonstrated a good mechanical properties and a good osteointegration. The calorimetric test evidenced a range of temperature adapted to biological environment.
REFERENCES
1. O. Bretcanu et al. Journal of Magnetism and Magnetic Materials, 305 (2006) 529-533.
ACKNOWLEDGMENTS
The authors would like to thank to the MIUR Grant for Young researchers 2012.
SESSION
Materials and Devices for Emerging Clinical Challenge
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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