4,108 research outputs found
Exact solutions of Brans-Dicke cosmology with decaying vacuum density
We investigate cosmological solutions of Brans-Dicke theory with both the
vacuum energy density and the gravitational constant decaying linearly with the
Hubble parameter. A particular class of them, with constant deceleration
factor, sheds light on the cosmological constant problems, leading to a
presently small vacuum term, and to a constant ratio between the vacuum and
matter energy densities. By fixing the only free parameter of these solutions,
we obtain cosmological parameters in accordance with observations of both the
relative matter density and the universe age. In addition, we have three other
solutions, with Brans-Dicke parameter w = -1 and negative cosmological term,
two of them with a future singularity of big-rip type. Although interesting
from the theoretical point of view, two of them are not in agreement with the
observed universe. The third one leads, in the limit of large times, to a
constant relative matter density, being also a possible solution to the cosmic
coincidence problem.Comment: Minor changes, references added. Version accepted for publication in
Classical and Quantum Gravit
Exact solutions of Brans-Dicke cosmology and the cosmic coincidence problem
We present some cosmological solutions of Brans-Dicke theory, characterized
by a decaying vacuum energy density and by a constant relative matter density.
With these features, they shed light on the cosmological constant problems,
leading to a presently small vacuum term, and to a constant ratio between the
vacuum and matter energy densities. By fixing the only free parameter of our
solutions, we obtain cosmological parameters in accordance with observations of
the relative matter density, the universe age and redshift-distance relations.Comment: To appear in Brazilian Journal of Physics (proceedings of the
conference 100 Years of Relativity, Sao Paulo, August 2005
Time Series Analysis of Export Demand Equations: A Cross-Country Analysis
The paper estimates export demand elasticities for a large number of developing and industrial countries, using time-series techniques that account for the nonstationarity in the data. The average long-run price and income elasticities are found to be approximately -1 and 1.5, respectively. Thus, exports do react to both the trade partners' income and to relative prices. Africa faces the lowest income elasticities for its exports, while Asia has both the highest income and price elasticities. The price and income elasticity estimates have good statistical properties. Copyright 1999, International Monetary Fund
Theater Studies in Creative Drama - A Journey of Transformation
The Theater Studies in Creative Drama project at UCF aimed to explore and implement Drama-Based Instruction (DBI) in education, with a specific focus on creating a lesson plan for children in hospitals. The project began by delving into the significance of play in childhood and its connection to theater. Through interdisciplinary collaboration with UCF nursing students, the team crafted a dynamic lesson plan, incorporating theatrical elements to enhance the educational experience for young patients. The To-Go Package, designed for children unable to attend in person, extended the impact of the project. The key activities involved reflection on personal experiences, connecting play to theater, understanding diversity, and communicating in diverse ways. Through this journey, I learned that DBI is a powerful tool for fostering creativity, communication skills, and empathy, transforming the traditional learning experience into a dynamic and inclusive educational approach.https://stars.library.ucf.edu/hip-2023fall/1078/thumbnail.jp
Les derniers écrits d’Adam Scot. Analyse linguistique et stylistique du «De quadripertito exercitio cellae». [Reseña]
Reseña de: Francesco PALLESCHI, Les derniers écrits d’Adam
Scot. Analyse linguistique et stylistique
du «De quadripertito exercitio cellae», Universität
Salzburg («Analecta Cartusiana», 168),
Salzburgo 2002, 199 pp
An early witness to the nature of the Canonical Order in the twelflh Century. A study in the life and writings of Adam Scot, with particular reference to his understanding of the Rule of St. Augustine. [Reseña]
Reseña de: David JONES, An early witness to the nature
of the Canonical Order in the twelflh Century.
A study in the life and writings of Adam Scot,
with particular reference to his understanding
of the Rule of St. Augustine, Universität Salzburg
(«Analecta Cartusiana», 151), Salzburgo
1999, 316 + VIII pp
Fundación y progresos de Ara Christi, convento de religiosos cartuxos. (Archivo Histórico Nacional de Madrid, Códices, 1.372 B). [Reseña]
Reseña de: Dom Juan Bautista GINER Y ARAGÓN, Fundación
y progresos de Ara Christi, convento
de religiosos cartuxos. (Archivo Histórico Nacional
de Madrid, Códices, 1.372 B), edición
crítica y transcripción de Albert Ferrer Orts,
prólogo de Antonio Ballester Ballester, Universität
Salzburg («Analecta Cartusiana», 196),
Salzburgo 2003, 92 + XXXII pp
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