Southern Cross University of Brazil

Sao Paulo, Brazil

Southern Cross University of Brazil

Sao Paulo, Brazil
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Shyam R.,Saha Institute of Nuclear Physics | Tsushima K.,Southern Cross University of Brazil
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2017

We investigate the production of charm-baryon hypernucleus OΛc +16 in the antiproton–O16 collisions within a fully covariant model that is based on an effective Lagrangian approach. The explicit Λ¯c −Λc + production vertex is described by the t-channel D0 and D⁎0 meson-exchanges in the initial collision of the incident antiproton with one of the protons of the target nucleus. The Λc + bound state spinors as well as the self-energies of the exchanged mesons employed in our calculations are derived from the quark–meson coupling model. The parameters of various vertices are taken to be the same as those used in our previous study of the elementary p¯+p→Λ¯c −+Λc + reaction. We find that for antiproton beam momenta of interest to the P¯ANDA experiment, the 0∘ differential cross sections for the formation of OΛc +16 hypernuclear states with simple particle–hole configurations, have magnitudes in the range of a few μb/sr. © 2017 The Author(s)

Toledo D.R.,University of Sao Paulo | Barela J.A.,Southern Cross University of Brazil | Barela J.A.,São Paulo State University | Barela J.A.,Institute Ciencias da Atividade Fisica e Esporte
Experimental Brain Research | Year: 2014

Patterns of adaptive changes to the exposure to a sinusoidal visual stimulus can be influenced by stimulus characteristics as well as the integrity of the sensory and motor systems involved in the task. Sensorimotor deficits due to aging might alter postural responses to visual manipulation, especially in more demanding tasks. The purpose of this study was to compare postural control between young and older adults at different levels of complexity and to examine whether possible sensory and/or motor changes account for postural performance differences in older adults. Older and young adults were submitted to the following tests: postural control assessments, i.e., body sway during upright stance and induced by movement of a visual scene (moving room paradigm); sensory assessments, i.e., visual (acuity and contrast sensitivity) and somatosensory (tactile foot sensitivity and detection of passive ankle motion); and motor assessments, i.e., isometric ankle torque and muscular activity latency after stance perturbation. Older adults had worse sensory and motor performance, larger body sway amplitude during stance and stronger coupling between body sway and moving room motion than younger adults. Multiple linear regression analyses indicated that the threshold for the detection of passive ankle motion contributed the most to variances in body sway and this contribution was more striking when visual information was manipulated in a more unpredictable way. The present study suggests that less accurate information about body position is more detrimental to controlling body position, mainly for older adults in more demanding tasks. © 2013 Springer-Verlag Berlin Heidelberg.

de Melo J.P.B.C.,Southern Cross University of Brazil | Tsushima K.,Southern Cross University of Brazil | Ahmed I.,Southern Cross University of Brazil | Ahmed I.,Quaidi i Azam University Campus
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2017

Pion valence distributions in nuclear medium and vacuum are studied in a light-front constituent quark model. The in-medium input for studying the pion properties is calculated by the quark-meson coupling model. We find that the in-medium pion valence distribution, as well as the in-medium pion valence wave function, are substantially modified at normal nuclear matter density, due to the reduction in the pion decay constant. © 2017 The Authors

Coelho P.R.T.,University of Sao Paulo | Coelho P.R.T.,Southern Cross University of Brazil
Monthly Notices of the Royal Astronomical Society | Year: 2014

Theoretical stellar libraries have been increasingly used to overcome limitations of empirical libraries, e.g. by exploring atmospheric parameter spaces not well represented in the latter. This work presents a new theoretical library which covers 3000 ≤ Teff ≤ 25 000 K,-0.5 ≤ log g ≤ 5.5 and 12 chemical mixtures covering 0.0017 ≤ Z ≤ 0.049 at both scaledsolar and α-enhanced compositions. This library complements previous ones by providing: (i) homogeneous computations of opacity distribution functions, models atmospheres, statistical surface fluxes and high-resolution spectra; (ii) high-resolution spectra with continua slopes corrected by the effect of predicted lines and (iii) two families of α-enhanced mixtures for each scaled-solar iron abundance, to allow studies of the α-enhancement both at 'fixed iron' and 'fixed Z' cases. Comparisons to observed spectra were performed and confirm that the synthetic spectra reproduce well the observations, although there are wavelength regions which should be still improved. The atmospheric parameter scale of the model library was compared to one derived from a widely used empirical library, and no systematic difference between the scales was found. This is particularly reassuring for methods which use synthetic spectra for deriving atmospheric parameters of stars in spectroscopic surveys © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Caproni A.,Southern Cross University of Brazil | Abraham Z.,University of Sao Paulo | Monteiro H.,Federal University of Itajubá
Monthly Notices of the Royal Astronomical Society | Year: 2013

BL Lacertae is the prototype of the BL Lac class of active galactic nuclei, exhibiting intensive activity on parsec (pc) scales, such as intense core variability and multiple ejections of jet components. In particular, in previousworks the existence of precession motions in the pc-scale jet of BL Lacertae has been suggested. In this work we revisit this issue, investigating temporal changes of the observed right ascension and declination offsets of the jet knots in terms of our relativistic jet-precession model. The seven free parameters of our precession model were optimized via a heuristic cross-entropy method, comparing the projected precession helix with the positions of the jet components on the plane of the sky and imposing constraints on their maximum and minimum superluminal velocities. Our optimized best model is compatible with a jet having a bulk velocity of 0.9824c, which is precessing with a period of about 12.1 yr in the observer's reference frame and changing its orientation in relation to the line of sight between 4° and 5°, approximately. Assuming that the jet precession has its origin in a supermassive binary black hole system, we show that the 2.3-yr periodic variation in the structural position angle of the very-long-baseline interferometry (VLBI) core of BL Lacertae reported by Stirling et al. is compatible with a nutation phenomenon if the secondary black hole has a mass higher than about six times that of the primary black hole. © 2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Vinolo M.A.R.,University of Sao Paulo | Hirabara S.M.,Southern Cross University of Brazil | Curi R.,University of Sao Paulo
Current Opinion in Clinical Nutrition and Metabolic Care | Year: 2012

Purpose of review: It has been demonstrated that fatty acids (FAs) are physiological ligands of G-protein-coupled receptors (GPRs). Activation of the GPRs (40, 41, 43, 84, 119 and 120) by FAs or synthetic agonists modulates several responses. In this review, we discuss the current knowledge on the actions of FA-activated GPRs and their relevance in normal and pathological conditions. Recent findings: Studies have shown that FA-activated GPRs modulate hormone secretion (incretin, insulin and glucagon), activation of leukocytes and several aspects of metabolism. Summary: Understanding GPR actions and their involvement in the development of insulin-resistance, β-cell failure, dyslipidemia and inflammation associated with obesity, type 2 diabetes, metabolic syndrome and cardiovascular diseases is important for the comprehension of the mechanisms underlying these pathological conditions and for the establishment of new and effective interventions. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

de Melo J.P.B.C.,Southern Cross University of Brazil | Frederico T.,Brazilian Technological Institute of Aeronautics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

The issue of the contribution of zero-modes to the light-front projection of the electromagnetic current of phenomenological models of vector particles vertices is addressed in the Drell-Yan frame. Our analytical model of the Bethe-Salpeter amplitude of a spin-1 fermion-antifermion composite state gives a physically motivated light-front wave function symmetric by the exchange of the fermion and antifermion, as in the ρ-meson case. We found that among the four independent matrix elements of the plus component in the light-front helicity basis only the 0 → 0 one carries zero-mode contributions. Our derivation generalizes to symmetric models, important for applications, the above conclusion found for a simplified non-symmetrical form of the spin-1 Bethe-Salpeter amplitude with photon-fermion point-like coupling and also for a smeared fermion-photon vertex model. © 2012 Elsevier B.V.

Rojas E.,Southern Cross University of Brazil | El-Bennich B.,Southern Cross University of Brazil | De Melo J.P.B.C.,Southern Cross University of Brazil
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We study ground and radial excitations of flavor singlet and flavored pseudoscalar mesons within the framework of the rainbow-ladder truncation using an infrared massive and finite interaction in agreement with recent results for the gluon-dressing function from lattice QCD and Dyson-Schwinger equations. Whereas the ground-state masses and decay constants of the light mesons as well as charmonia are well described, we confirm previous observations that this truncation is inadequate to provide realistic predictions for the spectrum of excited and exotic states. Moreover, we find a complex conjugate pair of eigenvalues for the excited D(s) mesons, which indicates a non-Hermiticity of the interaction kernel in the case of heavy-light systems and the present truncation. Nevertheless, limiting ourselves to the leading contributions of the Bethe-Salpeter amplitudes, we find a reasonable description of the charmed ground states and their respective decay constants. © 2014 American Physical Society.

Genovese W.J.,Southern Cross University of Brazil
Photomedicine and laser surgery | Year: 2010

OBJECTIVE: To review the literature regarding the use of surgical lasers in hemangioma treatment and to report a clinical case involving diode laser. BACKGROUND: Hemangiomas are benign vascular proliferations consisting of numerous capillary structures and are especially common on the tongue, lips, jugal mucous membrane, and gums. A number of treatment modalities have been proposed for hemangioma treatment. METHODS: The patient was referred for evaluation complaining of chewing difficulty because of swelling in the right area of the upper lip, with no previous trauma. The lesion was located in the internal right jugal mucous membrane, measured 4 x 4 cm(2), presented a bluish coloration, and was diagnosed as a hemangioma. The treatment selected was surgical removal using gallium arsenide (GaAs) diode laser at 980 nm wavelength, with 4.0 W of power. RESULTS: During surgery, complications including hemorrhage were not observed, and no scarring developed after surgery. CONCLUSIONS: The use of GaAs high-potency diode laser in the treatment of hemangioma reduced bleeding during surgery, with a consequent reduction in operating time, and promoted rapid postoperative hemostasis. It is safe for use on large lesions and easy to manage, and postoperative problems, including potential scarring, and discomfort are minimal.

Coelho P.,Southern Cross University of Brazil | Gadotti D.A.,European Southern Observatory
Astrophysical Journal Letters | Year: 2011

We obtained stellar ages and metallicities via spectrum fitting for a sample of 575 bulges with spectra available from the Sloan Digital Sky Survey. The structural properties of the galaxies have been studied in detail in 2009 by Gadotti and the sample contains 251 bulges in galaxies with bars. Using the whole sample, where galaxy stellar mass distributions for barred and unbarred galaxies are similar, we find that bulges in barred and unbarred galaxies occupy similar loci in the age versus metallicity plane. However, the distribution of bulge ages in barred galaxies shows an excess of populations younger than ∼4 Gyr, when compared to bulges in unbarred galaxies. Kolmogorov-Smirnov statistics confirm that the age distributions are different with a significance of 99.94%. If we select sub-samples for which the bulge stellar mass distributions are similar for barred and unbarred galaxies, this excess vanishes for galaxies with bulge mass log M < 10.1 M ⊙, while for more massive galaxies we find a bimodal bulge age distribution for barred galaxies only, corresponding to two normal distributions with mean ages of 10.4 and 4.7Gyr. We also find twice as much active galactic nuclei among barred galaxies, as compared to unbarred galaxies, for low-mass bulges. By combining a large sample of high-quality data with sophisticated image and spectral analysis, we are able to find evidence that the presence of bars affects the mean stellar ages of bulges. This lends strong support to models in which bars trigger star formation activity in the centers of galaxies. © 2011. The American Astronomical Society. All rights reserved.

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