1,575 research outputs found
Romanticism in Spain ..
Typewritten sheets in cover.
Thesis (M.A.)--Boston University
This item was digitized by the Internet Archive.
Bibliography: p. 45-46
Accelerated FRW Solutions in Chern-Simons Gravity
We consider a five-dimensional Einstein-Chern-Simons action which is composed
of a gravitational sector and a sector of matter, where the gravitational
sector is given by a Chern-Simons gravity action instead of the
Einstein-Hilbert action and where the matter sector is given by the so called
perfect fluid. It is shown that (i) the Einstein-Chern-Simons (EChS) field
equations subject to suitable conditions can be written in a similar way to the
Einstein-Maxwell field equations; (ii) these equations have solutions that
describe accelerated expansion for the three possible cosmological models of
the universe, namely, spherical expansion, flat expansion and hyperbolic
expansion when , a parameter of theory, is greater than zero. This
result allow us to conjeture that this solutions are compatible with the era of
Dark Energy and that the energy-momentum tensor for the field , a
bosonic gauge field from the Chern-Simons gravity action, corresponds to a form
of positive cosmological constant.
It is also shown that the EChS field equations have solutions compatible with
the era of matter: (i) In the case of an open universe, the solutions
correspond to an accelerated expansion () with a minimum scale
factor at initial time that, when the time goes to infinity, the scale factor
behaves as a hyperbolic sine function. (ii) In the case of a flat universe, the
solutions describing an accelerated expansion whose scale factor behaves as a
exponencial function when time grows. \item In the case of a closed universe it
is found only one solution for a universe in expansion, which behaves as a
hyperbolic cosine function when time grows.Comment: 58 pages, 24 figure
Evolving Lorentzian wormholes supported by phantom matter with constant state parameters
In this paper we study the possibility of sustaining an evolving wormhole via
exotic matter made out of phantom energy. We show that this exotic source can
support the existence of evolving wormhole spacetimes. Explicitly, a family of
evolving Lorentzian wormholes conformally related to another family of
zero-tidal force static wormhole geometries is found in Einstein gravity.
Contrary to the standard wormhole approach, where first a convenient geometry
is fixed and then the matter distribution is derived, we follow the
conventional approach for finding solutions in theoretical cosmology. We derive
an analytical evolving wormhole geometry by supposing that the radial tension
(which is negative to the radial pressure) and the pressure measured in the
tangential directions have barotropic equations of state with constant state
parameters. At spatial infinity this evolving wormhole, supported by this
anisotropic matter, is asymptotically flat, and its slices constant are
spaces of constant curvature. During its evolution the shape of the wormhole
expands with constant velocity, i.e without acceleration or deceleration, since
the scale factor has strictly a linear evolution.Comment: 9 pages, 2 figures, Accepted for publication in Phys. Rev.
Eliciting mathematics educators’ professional knowledge on the didactical suitability of the integral calculus study process
II Congreso Internacional Virtual sobre el Enfoque Ontosemiótico del Conocimiento y la Instrucción Matemáticos (CIVEOS-2), 23-26 de marzo de 2017. [http://enfoqueontosemiotico.ugr.es/]A articulação entre os conhecimentos derivados das investigações acadêmicas e das práticas
profissionais de professores-formadores de professores de matemática consiste em um tema
de investigação relevante na área de Educação Matemática. Nesse sentido, desenvolvemos
uma pesquisa qualitativa, baseada em um estudo de casos, com o objetivo de caracterizar os
conhecimentos profissionais de professores-formadores sobre a idoneidade didática de
processos de estudo do Cálculo Integral. Isto é feito através da articulação dos resultados da
investigação em Didática do Cálculo com os conhecimentos de profissionais manifestados
por uma amostra de professores-formadores, experts em didática do Cálculo Integral, que
atuam na formação inicial e continuada de professores no Brasil. Entre os principais
resultados, ressaltamos a potencialidade das ferramentas teóricas do Enfoque
Ontosemiótico para a sistematização dos conhecimentos profissionais que emergiram das
narrativas desses formadores.The articulation between the knowledge derived from academic research and the
professional practices of mathematics teachers’ educatorsis a relevant research topic in
Mathematics Education. In this paper we develop a qualitative research, based on a case
study, with the objective of characterising the professional knowledge of mathematics
teacher’s educator on the didactic suitability of theintegral calculus study processes. This
study is carried out through the articulation of researchin didactics of calculus with the
professional knowledge manifested by a sample of mathematics educators, experts in the
didactics of integral calculus, who work in the initial and continuous training of teachers in
Brazil. Among the main results, we highlight the potential of the Onto-semiotic Approach
theoretical tools for systematising the professional knowledge that emerged from the
narratives of these mathematics teachers’ educators
Diseño del mejoramiento del servicio agua potable y unidades básicas de saneamiento del Barrio Churulla, Comunidad de Hercca, distrito de Sicuani, provincia de Canchis – Cusco
La construcción de un eficiente Sistema Integral de Agua y Saneamiento, es un
ente primordial para los Gobiernos, en tal sentido se plantea el presente proyecto
Diseño de mejoramiento del servicio agua potable y unidades básicas de
saneamiento rural del Barrio Churulla, Comunidad de Hercca, Distrito de Sicuani,
Provincia de Canchis – Cusco, con la finalidad que los habitantes mejoren su
calidad de vida. El tipo de investigación es de tipo no experimental-transversal, que
abastece a 235 habitantes.
Se diseña el Sistema de Agua Potable y Unidades Básicas Saneamiento,
compuesto por unas captaciones tipo ladera, lÃnea de conducción, Reservorio
rectangular apoyado con su caseta de cloración, redes de distribución con tuberÃas,
cámaras rompe-presión CRP Tipo 6 el cual es empleada en lÃnea de conducción
cuya finalidad es únicamente de reducir la presión en la tuberÃa y el CRP Tipo 7 es
utilizada en la red de distribución, además de reducir la presión regula el
abastecimiento mediante el accionamiento de la válvula flotadora. Sistema de
saneamiento se cuenta con Unidades Básicas de Saneamiento con arrastre
hidráulico, empleando biodigestores para las 63 viviendas y la Iglesia, con zanjas
de infiltración para la deposición de las aguas, teniendo en cuenta los parámetros
establecidos en el Reglamento Nacional de Edificaciones en el rubro de Obras de
Saneamiento. El proyecto tiene un costo final de S/. 1,144,634.61
Appendix por el arcediano y canonigo de Tarazona, el dotor [sic] Ivan Sanz de Cortes ...
Copia digital : Diputación Provincial de Zaragoza. Servicio de Archivos y Bibliotecas, 2010Datos de tÃt. sacados de p.1, y mención de responsabilidad del final del textoFecha del final del texto 1649Sign.: A\p4\
Por el Dotor Ivan Sanz de Cortes arcediano y canonigo de Tarazona, con Agustin Garcia de la Torre, en la declaracion que pide
Copia digital : Diputación Provincial de Zaragoza. Servicio de Archivos y Bibliotecas, 2010Datos de tÃt. tomados de p.1, y mención de responsabilidad del final del textoTexto fechado al final del mismo en 1649Sign.: A\p3\
Instalación y configuración de Zentyal Server para implementar y administrar servicios en infraestructura de TI
Este documento consolida los resultados de la evaluación final actividad correspondiente al curso de profundización en Linux; en el cual cada uno de los alumnos selecciona un tema a desarrollar a través de GNU/ Servidor Linux Zentyal, y la implementación de diferentes servicios de infraestructura se lleva a cabo DNS, DHCP, Firewall y controladores de dominio, dando solución a los problemas planteados.This document consolidates the results of the final evaluation activity corresponding to the Linux deepening course; in which each student selects a topic to develop through GNU / Zentyal Linux Server, and the implementation of different infrastructure services is carried out DNS, DHCP, Firewall and domain controllers, providing solutions to the problems raised
Delayed administration of allogeneic cardiac stem cell therapy for acute myocardial infarction could ameliorate adverse remodeling: experimental study in swine
Preclinical Evaluation of the Safety and Immunological Action of Allogeneic ADSC-Collagen Scaffolds in the Treatment of Chronic Ischemic Cardiomyopathy
The use of allogeneic adipose-derived mesenchymal stromal cells (alloADSCs) represents an attractive approach for treating myocardial infarction (MI). Furthermore, adding a natural support improves alloADSCs engraftment and survival in heart tissues, leading to a greater therapeutic effect. We aimed to examine the safety and immunological reaction induced by epicardial implantation of a clinical-grade collagen scaffold (CS) seeded with alloADSCs for its future application in humans. Thus, cellularized scaffolds were myocardially or subcutaneously implanted in immunosuppressed rodent models. The toxicological parameters were not significantly altered, and tumor formation was not found over the short or long term. Furthermore, biodistribution analyses in the infarcted immunocompetent rats displayed cell engraftment in the myocardium but no migration to other organs. The immunogenicity of alloADSC-CS was also evaluated in a preclinical porcine model of chronic MI; no significant humoral or cellular alloreactive responses were found. Moreover, CS cellularized with human ADSCs cocultured with human allogeneic immune cells produced no alloreactive response. Interestingly, alloADSC-CS significantly inhibited lymphocyte responses, confirming its immunomodulatory action. Thus, alloADSC-CS is likely safe and does not elicit any alloreactive immunological response in the host. Moreover, it exerts an immunomodulatory action, which supports its translation to a clinical setting
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