3,854 research outputs found
Constraining Lorentz invariance violations using the Crab pulsar TeV emission
Fast variations of gamma-ray flux from Active Galactic Nuclei and Gamma-Ray
Bursts can constrain Lorentz Invariance Violation (LIV) because of the delayed
(or advanced) arrival of photons with higher energies: this approach has lead
to the current world-best limits on the energy scale of Quantum Gravity. Here
we report on constraints on LIV studying the gamma-ray emission up to TeV
energies from the Galactic Crab pulsar, recently discovered by the MAGIC
collaboration. A likelihood analysis of the pulsar events reconstructed for
energies above 400 GeV finds no significant variation of energy-dependent
arrival time, and 95% CL limits are then obtained on the effective LIV energy
scale after taking into account systematic uncertainties. Only a factor of
about two less constraining than the current world-best limit on a quadratic
LIV scenario, pulsars are now well established as a third and independent class
of astrophysical objects suitable to constrain the characteristic energy scale
of LIV.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC
2017), Bexco, Busan, Korea (arXiv:1708.05153
Dealing with Integer-valued Variables in Bayesian Optimization with Gaussian Processes
Bayesian optimization (BO) methods are useful for optimizing functions that
are expensive to evaluate, lack an analytical expression and whose evaluations
can be contaminated by noise. These methods rely on a probabilistic model of
the objective function, typically a Gaussian process (GP), upon which an
acquisition function is built. This function guides the optimization process
and measures the expected utility of performing an evaluation of the objective
at a new point. GPs assume continous input variables. When this is not the
case, such as when some of the input variables take integer values, one has to
introduce extra approximations. A common approach is to round the suggested
variable value to the closest integer before doing the evaluation of the
objective. We show that this can lead to problems in the optimization process
and describe a more principled approach to account for input variables that are
integer-valued. We illustrate in both synthetic and a real experiments the
utility of our approach, which significantly improves the results of standard
BO methods on problems involving integer-valued variables.Comment: 7 page
Ramón Pérez de Ayala y las novelas de 1902: ruptura modernista y renovación literaria
Se destacan las contribuciones que
Pérez de Ayala realizó con respecto a la
renovación novelística de inicios del
siglo XX, y la deuda que toda la
narrativa de su primera época creativa
tiene con respecto al cambio de actitud
modernista
Monografía histórico-descriptiva de la Catedral de Burgos
Ded. autógr. del autor.Extracto del Anuario Eclesiástico para 1928.Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 201
Forms of Life and Subjectivity
"Forms of Life and Subjectivity: Rethinking Sartre’s Philosophy explores the fundamental question of why we act as we do. Informed by an ontological and phenomenological approach, and building mainly, but not exclusively, on the thought of Sartre, Daniel Rueda Garrido considers the concept of a ""form of life” as a term that bridges the gap between subjective identity and communities.
This first systematic ontology of ""forms of life” seeks to understand why we act in certain ways, and why we cling to certain identities, such as nationalisms, social movements, cultural minorities, racism, or religion. The answer, as Rueda Garrido argues, depends on an understanding of ourselves as ""forms of life” that remains sensitive to the relationship between ontology and power, between what we want to be and what we ought to be.
Structured in seven chapters, Rueda Garrido’s investigation yields illuminating and timely discussions of conversion, the constitution of subjectivity as an intersubjective self, the distinction between imitation and reproduction, the relationship between freedom and facticity, and the dialectical process by which two particular ways of being and acting enter into a situation of assimilation-resistance, as exemplified by capitalist and artistic forms of life.
This ambitious and original work will be of great interest to scholars and students of philosophy, social sciences, cultural studies, psychology and anthropology. Its wide-ranging reflection on the human being and society will also appeal to the general reader of philosophy.
Sobre escritura y alfabetización. Lugares de encuentro entre psicología e historia
The development of cultural psychology responds to an attempt to explain the mind-culture equation in a way that goes beyond the black box theories which have characterized transcultural studies. This article aims to analyse the role of writing and its diffusion through literacy in the complexrelationship between mind and culture from a historical-cultural perspective. A perspective of this kind may improve on the traditional comparative approaches of black box models. To this end, the authorproposes to study writing and literacy as a meeting point between psychology and history, an endeavour made possible by recent advances in the historyofphilosophy, the history of culture and relatedfields (Gellner, 1994; Chartier, 1996; ver Cavallo y Chart,ier, 1998; Ong, 1982, Havelock, 1991, 1996; LAH, 1988; Luria, 1980; Scribner y Cole, 1981; Ramírez, 1995; Ramírez & Cubero, 1995; Ramirez d Wertsch, 1997). An approach of this kind allows the joint study of writing as a technique for communication and the recording of knowledge, and the reasons and attitudes that have influenced its dzfision via literacy ut key historical moments.La psicología cultural debe su desarrollo al intento de esclarecer la ecuación mente-cultura superando los modelos de caja negra característicos de los estudios transculturales. Este articulo pretende analizar el papel cumplido por la escritura y su dzfusión a través de la alfabetización en la compleja relación entre mente y cultura desde una óptica histórico-cultural superadora de los tradicionales enfoques comparativos característicos de los modelos de caja negra. Para ello, el autorpropone el estudio de la escritura y la alfabetización como lugar de encuentro entre psicología e historia, lo que es posible a partir de los últimos avances de la historia filosófica, la historia de la cultura y campos anexos (Gellner, 1994; Chartier, 1996; Cavallo y Chartier, 1998; Ong, 1982, Havelock, 1991, 1996; LAH, 1988; Luria, 1980; Scribner y Cole, 1981; Ramírez, 1995; Ramírez y Cubero, 1995; Ramírez y Wertsch, 1997). Una aproximación de estas características permite abordar el estudio conjunt0 de las propiedades que la escritura ofrece en tanto que tecnologia para la comunicación y registro del conocimiento, y los motivos y actitudes que han condicionado su dzfusión a través de la alfabetización en diversos momentos históricos
La creación del mundo en el arte medieval: La Sinagoga del Tránsito
La importancia que tiene el relato de la creación del mundo (Gen 1-2) para judíos, cristianos y musulmanes, se refleja en diferentes manifestaciones artísticas medievales. Este artículo analiza algunas de las representaciones a que dio lugar dicho relato, y al uso diverso del lenguaje artístico –figurativo y no figurativo– a que recurrieron los artistas. La segunda parte del artículo se centra en el examen de la Sinagoga del Tránsito de Toledo y propone, a través del estudio conjunto de decoración y epigrafía, y de algunos referentes culturales judíos, una interpretación que descubre en sus muros una representación no figurativa y simbólica del capítulo primero del Génesis.The significance that the account of Creation in Gen 1-2 has for Jews, Christians and Moslems is evident in different medieval art works. This essay analyses some of the art works derived from this narrative, as well as the use by artists of figurative and non-figurative artistic language in portraying it. The second section of the essay focuses on the Synagogue of El Transito of Toledo. There, i put forward an interpretation based on the joint analysis of decoration and epigraphy, as well as of some cultural Jewish elements. it unveils a non-figurative and symbolic depiction of first chapter of Genesis represented in the synagogue’s walls
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