5,728 research outputs found
A study of Double Pomeron Exchange in ALICE
The non-Abelian nature of QCD suggests that particles that have a gluon
constituent, such as glueballs or hybrids, should exist. Experiments WA76, WA91
and WA102 have performed a dedicated search for these states in central
production using the CERN Omega Spectrometer. New results from central
production show that there is a kinematical filter which can select out
glueball candidates from known qqbar states. A further study of this at high
energies is essential in order to get information on the M(X0) > 2 GeV region.
This paper describes how this could be done using the the ALICE detector at the
LHC.Comment: 17 pages, Latex, 7 Figure
Transcultural adaptation of the who oral health questionnaire and its validation in chilean children
Indexación: Scopus.Introduction: The last edition of the WHO "Oral Health Questionnaire for Children" was published in 2013. This is an only-English version, and as such it requires linguistic adaptation and validation to be applied in the Chilean population. Objectives: To translate and adapt the WHO Oral Health Questionnaire for Children to Spanish and validate it in a Chilean population. Methods: A translation and back translation of the original instrument from English to Spanish was carried out by four translators. The questionnaire was self-reported as a pilot test in ten individuals. A sample was subsequently selected for convenience taking into account the population distribution, resulting in a final sample of 103 individuals. The internal consistency was calculated with Cronbach's alpha, criterion validity with Pearson's correlation coefficient and construct validity with Exploratory Factor Analysis. Results: A conceptual and semantic equivalence of the instrument was obtained. Women and men accounted for 43.69% and 56.31% of the sample, respectively. Cronbach's alpha coefficient was 0.62, while criterion validity was slightly positive between the total dimensions and the DMFT (r=0.13, p-value= 0.20). The Exploratory Factor Analysis yielded a total of 11 factors that explain 70% of the variability in the data. Conclusions: The oral health questionnaire has been appropriately adapted to Spanish, having conceptual as well as semantic equivalence to the original version, being reliable and valid to be used in a population of 12-year-old Chilean children. © 2018, Universidad de Concepcion. All rights reserved.http://joralres.com/index.php/JOR/article/view/432/43
Fermionic field perturbations of a three-dimensional Lifshitz black hole in conformal gravity
We study the propagation of massless fermionic fields in the background of a
three-dimensional Lifshitz black hole, which is a solution of conformal
gravity. The black hole solution is characterized by a null dynamical exponent.
Then, we compute analytically the quasinormal modes, the area spectrum, and the
absorption cross section for fermionic fields. The analysis of the quasinormal
modes shows that the fermionic perturbations are stable in this background. The
area and entropy spectrum are evenly spaced. At the low frequency limit, it is
observed that there is a range of values of the angular momentum of the mode
that contributes to the absorption cross section, whereas it vanishes at the
high frequency limit. In addition, by a suitable change of variables a
gravitational soliton can also be obtained and the stability of the quasinormal
modes are studied and ensured.Comment: 14 pages; 3 figures. arXiv admin note: text overlap with
arXiv:1407.639
On the formation and physical properties of the Intra-Cluster Light in hierarchical galaxy formation models
We study the formation of the Intra-Cluster Light (ICL) using a semi-analytic
model of galaxy formation, coupled to merger trees extracted from N-body
simulations of groups and clusters. We assume that the ICL forms by (1) stellar
stripping of satellite galaxies and (2) relaxation processes that take place
during galaxy mergers. The fraction of ICL in groups and clusters predicted by
our models ranges between 10 and 40 per cent, with a large halo-to-halo scatter
and no halo mass dependence. We note, however, that our predicted ICL fractions
depend on the resolution: for a set of simulations with particle mass one order
of magnitude larger than that adopted in the high resolution runs used in our
study, we find that the predicted ICL fractions are ~30-40 per cent larger than
those found in the high resolution runs. On cluster scale, large part of the
scatter is due to a range of dynamical histories, while on smaller scale it is
driven by individual accretion events and stripping of very massive satellites,
, that we find to be the major contributors
to the ICL. The ICL in our models forms very late (below ), and a
fraction varying between 5 and 25 per cent of it has been accreted during the
hierarchical growth of haloes. In agreement with recent observational
measurements, we find the ICL to be made of stars covering a relatively large
range of metallicity, with the bulk of them being sub-solar.Comment: Accepted for Publication in MNRAS, 19 pages, 13 figures, 1 tabl
Efecto fotoprotector del pigmento melanina producido por el hongo marino Hortaea Werneckii aislado desde Ulva Sp. - Photoprotector effect of melanin pigments produced by Hortaea Werneckii, marine fungi isolated from Ulva Sp.
Visión estratégica de la Armada de Chile y de su relación con Argentina
Exposición realizada por el Comandante en Jefe de la Armada en la Academia de Guerra de la Armada Argentina,  octubre de 200
Unsupervised Text Classification: a Contractual Risk Detection Approach
Enterprise contracting process tends to be tedious when there is thousands of active contracts to manage. The aim of this work was to implement an automatic indexing and information retrieval method in order to classify the semantic structure within contract documents into two classes, risk and non-risk legal language, on the basis of terms contained in new documents further called queries. The technique implemented is term frequency as the transformation procedure for each of the documents and singular-value decomposition to represent such transformations into a set of optimized number of factors. Queries are analyzed as vectors formed from the linear combination of the terms and compared to known documents class with cosine values to determine the nature of the legal language (as risk or non-risk). The result of this work shows that the class detection is possible using the proposed methodology with high relative percentage of accuracy
- …