551 research outputs found
BTZ Solutions on Codimension-2 Braneworlds
We consider five-dimensional gravity with a Gauss-Bonnet term in the bulk and
an induced gravity term on a 2-brane of codimension-2. We show that this system
admits BTZ-like black holes on the 2-brane which are extended into the bulk
with regular horizons.Comment: 6 pages. Talk given at Recent Developments in Gravity (NEB XIII),
Thessaloniki, Greece, June 4-6, 2008
Quasinormal modes and thermodynamical aspects of the 3D Lifshitz black hole
We consider scalar and spinorial perturbations on a background described by a
three-dimensional Lifshitz black hole. We obtained the corresponding
quasinormal modes which perfectly agree with the analytical result for the
quasinormal frequency in the scalar case. The numerical results for the
spinorial perturbations reinforce our conclusion on the stability of the model
under these perturbations. We also calculate the area spectrum, which prove to
be equally spaced, as an application of our results.Comment: 8 pages, 5 figures. Prepared for "Recent Developments in Gravity (NEB
XV)", Chania, Greece, 20-23 June 201
Instability of the Time Dependent Horava-Witten Model
We consider scalar perturbations in the time-dependent Ho\u{r}ava-Witten
Model in order to probe its stability. We show that during the non-singular
epoque the model evolves without instabilities until it encounters the
curvature singularity where a big crunch is supposed to occur. We compute the
frequencies of the scalar field oscillation during the stable period and show
how the oscillations can be used to prove the presence of such a singularity.Comment: 12 pages, 4 figures. References added. Some comments clarified.
Accepted in Phys. Rev.
Control of multidrug resistant (MDR) Acinetobacter baumanii outbreak in a pediatric oncology unit by optimizing infection prevention (IP) and control measures
Shortcuts in a Nonlinear Dynamical Braneworld in Six Dimensions
We consider a dynamical brane world in a six-dimensional spacetime containing
a singularity. Using the Israel conditions we study the motion of a 4-brane
embedded in this setup. We analyse the brane behaviour when its position is
perturbed about a fixed point and solve the full nonlinear dynamics in the
several possible scenarios. We also investigate the possible gravitational
shortcuts and calculate the delay between graviton and photon signals and the
ratio of the corresponding subtended horizons.Comment: 26 pages, 9 figures. References and discussion added. Title changed
to match the version accepted in Class. and Quant. Gra
Enfermedad por reflujo gastroesofágico. Detalles nuevos de una enfermedad vieja
Disease caused by gastro esophageal reflux is a pathology of great prevalence in the world. Its treatment is very expensive and requires a deep knowledge of physiopathological aspects to understand the clinic problems and make an appropriate management. Among the mainaspects of physiopathology, the spontaneous relaxations of lower esophageal sphincter are an important morbidity cause like other aspects included in this review. Within the clinical aspect, it is fundamental the erosive and non-erosive classification, in addition to the characterizationbetween atypical and typical symptoms in order to implement a treatment according to patient's needs.La enfermedad por reflujo gastroesofágico representa una patología de gran prevalencia en el mundo, esta genera altos costos económicos y requiere un estricto conocimiento de aspectos fisiopatológicos para entender sus problemas clínicos y poder realizar un adecuado manejo. Dentro de los principales aspectos de la fisiopatología las relajaciones espontáneas del esfínter esofágico inferior representan una causa importante de morbilidad al igual que otros aspectos tratados en esta revisión. En el aspecto clínico es fundamental la clasificación en erosivo y no erosivo además de la caracterización entre síntomas atípicos y típicos para implementar un tratamiento acorde a las necesidades del paciente
Stability Analysis and Area Spectrum of 3-Dimensional Lifshitz Black Holes
In this work, we probe the stability of a three-dimensional Lifshitz
black hole by using scalar and spinorial perturbations. We found an analytical
expression for the quasinormal frequencies of the scalar probe field, which
perfectly agree with the behavior of the quasinormal modes obtained
numerically. The results for the numerical analysis of the spinorial
perturbations reinforce the conclusion of the scalar analysis, i.e., the model
is stable under scalar and spinor perturbations. As an application we found the
area spectrum of the Lifshitz black hole, which turns out to be equally spaced.Comment: 23 pages, 6 figures. References added. Version to appear in Phys.
Rev.
Perturbations of Gauss-Bonnet Black Strings in Codimension-2 Braneworlds
We derive the Lichnerowicz equation in the presence of the Gauss-Bonnet term.
Using the modified Lichnerowicz equation we study the metric perturbations of
Gauss-Bonnet black strings in Codimension-2 Braneworlds.Comment: 26 pages, no figures, clarifying comments and one reference added, to
be published in JHE
Hemorragia digestiva de origen oscuro: “una causa no sospechada”
Obscure gastrointestinal bleeding is found in 5-10% of cases of intestinal bleeding, recurring in 50% of cases. It is caused by various aetiologies which can make diagnosis a challenge, requiring various endoscopic procedures. Among the unusual causes are nematode intestinal parasites, prevalent in tropical areas and developing countries. The study presents the case of a patient with recurrent obscure gastrointestinal bleeding triggered by Ascaris lumbricoides, who required various hospitalisations, blood transfusions and a set of endoscopic procedures before the aetiological diagnosis and subsequent treatment. This demonstrates the necessity to know the true cost-effectiveness of preventive parasite control in all patients with gastrointestinal bleeding and negative results for the first endoscopic evaluation, taking the high prevalence of nematodes in our country into account.La hemorragia digestiva de origen oscuro se presenta en el 5 -10% del sangrado intestinal, con persistencia o recurrencia en el 50%, de los casos. Es ocasionado por varías etiologías, generando un desafío diagnóstico que requiere la realización de varios procedimientos endoscópicos. Entre las causas inusuales se encuentran las parasitosis intestinales por nematodos, siendo prevalentes en zonas tropicales y países en vía de desarrollo. Presentamos el caso de una paciente con hemorragia digestiva de origen oscuro manifiesto recurrente desencadenado por Ascaris lumbricoides, quien requirió varias hospitalizaciones, soporte transfusional y realización de un set de procedimientos endoscópicos previo al diagnóstico etiológico y posterior tratamiento planteando la necesidad de conocer la real costo efectividad de la desparasitación profiláctica en todo paciente con hemorragia intestinal y primera evaluación endoscópica estándar negativa, teniendo en cuenta la alta prevalencia de nematodos en nuestro país
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