Search results for "Normalization"
showing 10 items of 632 documents
Critical reflections on asymptotically safe gravity
2020
Asymptotic safety is a theoretical proposal for the ultraviolet completion of quantum field theories, in particular for quantum gravity. Significant progress on this program has led to a first characterization of the Reuter fixed point. Further advancement in our understanding of the nature of quantum spacetime requires addressing a number of open questions and challenges. Here, we aim at providing a critical reflection on the state of the art in the asymptotic safety program, specifying and elaborating on open questions of both technical and conceptual nature. We also point out systematic pathways, in various stages of practical implementation, towards answering them. Finally, we also take…
Adiabatic expansions for Dirac fields, renormalization, and anomalies
2018
11 pags.
Running Immirzi Parameter and Asymptotic Safety
2011
We explore the renormalization group (RG) properties of quantum gravity, using the vielbein and the spin connection as the fundamental field variables. We require the effective action to be invariant under the semidirect product of spacetime diffeomorphisms and local frame rotations. Starting from the corresponding functional integral we review the construction of an appropriate theory space and an exact funtional RG equation operating on it. We then solve this equation on a truncated space defined by a three parameter family of Holst-type actions which involve a running Immirzi parameter. We find evidence for the existence of an asymptotically safe fundamental theory. It is probably inequi…
Method to compute the stress-energy tensor for a quantized scalar field when a black hole forms from the collapse of a null shell
2020
A method is given to compute the stress-energy tensor for a massless minimally coupled scalar field in a spacetime where a black hole forms from the collapse of a spherically symmetric null shell in four dimensions. Part of the method involves matching the modes for the in vacuum state to a complete set of modes in Schwarzschild spacetime. The other part involves subtracting from the unrenormalized expression for the stress-energy tensor when the field is in the in vacuum state, the corresponding expression when the field is in the Unruh state and adding to this the renormalized stress-energy tensor for the field in the Unruh state. The method is shown to work in the two-dimensional case wh…
Histidine-rich glycoprotein-induced vascular normalization improves EPR-mediated drug targeting to and into tumors
2018
Tumors are characterized by leaky blood vessels, and by an abnormal and heterogeneous vascular network. These pathophysiological characteristics contribute to the enhanced permeability and retention (EPR) effect, which is one of the key rationales for developing tumor-targeted drug delivery systems. Vessel abnormality and heterogeneity, however, which typically result from excessive pro-angiogenic signaling, can also hinder efficient drug delivery to and into tumors. Using histidine-rich glycoprotein (HRG) knockout and wild type mice, and HRG-overexpressing and normal t241 fibrosarcoma cells, we evaluated the effect of genetically induced and macrophage-mediated vascular normalization on th…
ADT implementation and completion by induction from examples
1991
There exists a fast algorithm [2] for inductive synthesis of terminating and ground confluent term rewriting systems from samples. The principles of this algorithm and the methodology of its use for implementation and completion of abstract data types are described.
Occupations of Housing and Social Centers in Rome: A Durable Resistance to Neoliberalism and Institutionalization
2017
Squatting for housing and social centers has a long tradition in Rome since the end of the 1960s. By the mid-1970s, the occupation of buildings to set up political and social activities became part of the repertoire of left radical movements. In this chapter a set of 34 squatted spaces for housing and social centers in Rome active in 2014 is analysed. Squatting practices thus provide a lens to interpret the evolution of urban struggles, urban development and the changing sociopolitical contexts. Furthermore, Mudu and Rossini examine the role played by the processes of neutralization, co-optation, normalization and contention that explain the institutionalization of squatting in the city of …
“Te das cuenta de que el mundo puede ser tan distinto y similar al mismo tiempo”: Telecolaboración y desarrollo de la competencia intercultural en la…
2016
Este artículo versa sobre la integración de la telecolaboración, o intercambio intercultural en línea, en contextos de educación superior, para el desarrollo de la competencia intercultural en el aula inglés como lengua extranjera. Se analiza, desde la perspectiva de los estudiantes, un intercambio de telecolaboración en que participantes de España y de Estados Unidos colaboraron en grupos interculturales y plurinacionales para llevar a cabo una serie de tareas cuya complejidad cognitiva iba progresivamente en aumento: creación de un perfil digital, grabación de un vídeo de presentación, interacción multimodal (texto, audio, videoconferencia) para discutir y debatir los diferentes temas pro…
Las revistas científico-técnicas españolas de ciencias de la actividad física y el deporte: adecuación a las normas ISO y grado de normalización
2004
Este artículo tiene por objeto conocer el grado de normalización y la adecuación de las revistas científico-técnicas españolas del campo de las Ciencias de la Actividad Física y el Deporte a diversos apartados clave de las normas ISO 8-1977 e ISO 215-1986. A partir de la observación directa de los fascículos, se han confeccionado dos índices para calcular el Grado General de Normalización (GGN) y el Grado Fundamental de Normalización (GFN). Los resultados indican que el ajuste de las publicaciones a la norma ISO 8-1977 es equivalente a la de otros campos españoles como el de Economía y el de Tecnología, mientras que es menor en la norma ISO 215-1986. La mayoría de las revistas presentan un …
Approximate renormalization-group transformation for Hamiltonian systems with three degrees of freedom
1999
We construct an approximate renormalization transformation that combines Kolmogorov-Arnold-Moser (KAM)and renormalization-group techniques, to analyze instabilities in Hamiltonian systems with three degrees of freedom. This scheme is implemented both for isoenergetically nondegenerate and for degenerate Hamiltonians. For the spiral mean frequency vector, we find numerically that the iterations of the transformation on nondegenerate Hamiltonians tend to degenerate ones on the critical surface. As a consequence, isoenergetically degenerate and nondegenerate Hamiltonians belong to the same universality class, and thus the corresponding critical invariant tori have the same type of scaling prop…