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Concepcion, Chile

University of Bío-Bío is a university in Chile. It is part of the Chilean Traditional Universities.The University of Bío-Bío is heir of the tradition of state and public higher education in the Bío Bío Region. Its roots go back to the creation of the Technical University of the State , on April 9, 1947, and to the Ñuble Campus of the University of Chile. Then the Concepción Campus of the TUS and the campus from Chillán, derived in the Bío Bío University and the Chillán Professional Institute, originating what today is called the UBB.With offices in Concepción and Chillán, its mission is to generate, apply and communicate the knowledge in science, technology, arts and humanities, forming competent, integral and reflexive professionals to answer the regional and national needs, to serve society with excellence and quality.It offers 35 undergraduate degrees and two bachelor programs, with over 10.000 students and almost 70 percent of its professors hold masters or PhD grade. It has explored continuous education and graduate studies, contributing to the formation of advanced human capital in regions. Wikipedia.

Lopez-Sarrion J.,University of Santiago de Chile | Reyes C.M.,University of Bio Bio
European Physical Journal C | Year: 2012

We study the fermionic sector of the Myers and Pospelov theory with a general background n. The spacelike case without temporal component is well defined and no new ingredients came about, apart from the explicit Lorentz invariance violation. The lightlike case is ill defined and physically discarded. However, the other case where a nonvanishing temporal component of the background is present, the theory is physically consistent. We show that new modes appear as a consequence of higher time derivatives. We quantize the timelike theory and calculate the microcausality violation which turns out to occur near the light cone. © 2012 Springer-Verlag / Società Italiana di Fisica. Source

Cataldo M.,University of Bio Bio | Meza P.,University of Concepcion
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We investigate a family of inhomogeneous and anisotropic gravitational fields exhibiting a future singularity at a finite value of the proper time. The studied spherically symmetric spacetimes are asymptotically Friedmann-Robertson-Walker at spatial infinity and describe wormhole configurations filled with two matter components: one inhomogeneous and anisotropic fluid and another isotropic and homogeneously distributed fluid, characterized by the supernegative equation of state ω=p/ρ<-1. In previously constructed wormholes, the notion of the phantom energy was used in a more extended sense than in cosmology, where the phantom energy is considered a homogeneously distributed fluid. Specifically, for some static wormhole geometries the phantom matter was considered as an inhomogeneous and anisotropic fluid, with radial and lateral pressures satisfying the relations p r/ρ<-1 and pl≠pr, respectively. In this paper we construct phantom evolving wormhole models filled with an isotropic and homogeneous component, described by a barotropic or viscous phantom energy, and ending in a big rip singularity. In two of considered cases the equation of state parameter is constrained to be less than -1, while in the third model the finite-time future singularity may occur for ω<-1, as well as for -1<ω≤1. © 2013 American Physical Society. Source

Reyes C.M.,University of Bio Bio
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The unitarity in Lorentz invariance violating QED consisting of standard fermions and higher-order photons of the Myers-Pospelov theory is studied. We find ghost states associated to the higher-order character of the theory which could render the S-matrix nonunitary. An explicit calculation to check perturbative unitarity in the process of electron-positron scattering is performed and it is found to be possible to preserve unitarity. © 2013 American Physical Society. Source

Roberts J.M.,University of Pittsburgh | Escudero C.,University of Bio Bio
Pregnancy Hypertension | Year: 2012

The root cause of preeclampsia is the placenta. Preeclampsia begins to abate with the delivery of the placenta and can occur in the absence of a fetus but with the presence of trophoblast tissue with hydatidiform moles. In view of this, study of placenta should provide insight into the pathophysiology of preeclampsia. In this presentation we examine placental pathological and pathophysiological changes with preeclampsia and fetal growth restriction (FGR). It would seem that this comparison should be illuminating as both conditions are associated with similarly abnormal placentation yet only in preeclampsia is there a maternal pathophysiological syndrome. Similar insights about early and late-onset preeclampsia should also be provided by such information. We report that the placental abnormalities in preeclampsia are what would be predicted in a setting of reduced perfusion and oxidative stress. However, the differences from FGR are inconsistent. The most striking differences between the two conditions are found in areas that have been the least studied. There are differences between the placental findings in early and late-onset preeclampsia but whether these are qualitative, indicating different diseases, or simply quantitative differences within the same disease is difficult to determine. We attempt to decipher the true differences, seek an explanation for the disparate results and provide recommendations that we hope may help resolve these issues in future studies. © 2012 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved. Source

Cid A.,University of Bio Bio
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

We obtain conditions for the existence of an attractor in the system of equations describing a tachyon warm inflationary model with bulk viscosity taken into account. When these conditions are met the evolution approaches slow-roll regime. We present the primordial power spectrum for the tachyon field by considering a dissipation coefficient depending on the scalar field and temperature. © 2015 The Author. Source

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