1,720,961 research outputs found
Extracting Nuclear Form Factors from Coherent Neutrino Scattering
No full textRecently the COHERENT collaboration reported the first observation of coherent elastic neutrino nucleus scattering (CENNS), opening the door to the use of neutrinos for the study of nuclear properties. Studying the CENNS spectrum, indeed, it is possible to measure the electroweak nuclear form factor and therefore constrain the neutron distribution. It is possible to use the neutrinos produced in existing or planned accelerators in China for such an experiment: this opportunity will be discussed, as well as the impact of the systematic errors in the precision that can be achieved. Indeed, the uncertainty on the quenching factor can significantly affect the final result, this will be shown assuming the Helm model for the neutron distribution as well as using a model-independent analysis, based on the determination of the distribution's momenta
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
High-energy properties and low-energy phenomenology of scalarless Lorentz-violating Standard Model extensions
No full textLorentz symmetry is one of the best tested symmetries in nature. Usually it is considered to hold at arbitrarily high energies and large distances. However, in the last years a great amount of activity has been devoted to establish the limits of validity of this symmetry and predict the consequences of its hypothetical violation.
In a Lorentz-Violating theory, the UV behavior of the propagator can be improved adding terms containing higher space derivatives. The class of renormalizable theories can be significantly enlarged, while the absence of higher time derivatives ensures the unitarity of the S-matrix. If the additional terms satisfy a modified version of power counting (“weighted power counting”), in which the dimensions of the vertices are substituted by a weighted dimensions, then no higher-time derivatives are generated by renormalization.
In flat space and in the realm of perturbation theory, it is possible to construct theories that include scalars, fermions and gauge fields: it is possible to construct also Lorentz-Violating Standard Model Extensions (LVSMEs) without violating physical principles.
In some of these extensions, the four fermion interactions are renormalizable; they can trigger a Nambu--Jona-Lasinio mechanism that, due to a dynamical symmetry breaking, can generate a fermion condensate and give masses to the particles, also if the elementary scalars are suppressed. The Higgs bosons emerge at low-energy as a composite scalar field, together with the Goldstone bosons.
In this thesis we study some models of scalarless LVSMEs (i.e. no elementary scalar fields are present), in which the particles gain mass by means of the Nambu--Jona-Lasinio mechanism. First we calculate the effective potential, in the leading order of large N approximation. We show that there is a Lorentz-invariant minimum, and that, considering more generations of fermions, the CKM matrix can emerge. We compute the low-energy effective action and study the phenomenology of our model, in the leading order of large N limit.
At low-energy, one or more doublets of Higgs bosons can emerge as composite fields, with masses within the present experimental bounds. In this minimal LVSME, the neutrinos remain massless, but we show that the Lorentz-violating coefficients can also explain neutrino oscillations.
We examine also the high-energy properties of this model. Since the gauge couplings are super-renormalizable, they decouple and only the four fermion vertices are relevant. We study the most general model containing only four fermion interactions: we perform the one-loop renormalization and calculate the beta functions. We present a technique, inspired by Zimmermann's reduction of couplings, for the determination of the domain of asymptotic freedom in the case of several coupling constants, showing that this property is compatible with the dynamical symmetry breaking
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
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