33,680 research outputs found
Non-Declarative Sentences and Communication in Husserl’s Logical Investigations: contributions to a theory on communicative acts in the light of Husserl and Austin
Theses towards a new natural philosophy
In this paper I address some philosophical questions regarding the impact quantum
mechanics has in the classical conceptions about reality and knowledge. I stress that
onto-gnosiological realism still is an option to the issues regarding the relationship
between knowledge and reality. Rejecting some radical aspects of Copenhagen
interpretation of quantum formalism, I emphasize the advantages of de Broglie’s
realistic and causal model. To finish with, I discuss the limits of the Cartesian concept
of matter and the split between matter and mind
Acceleration field of a Universe modeled as a mixture of scalar and matter fields
A model of the Universe as a mixture of a scalar (inflaton or rolling tachyon
from the string theory) and a matter field (classical particles) is analyzed.
The particles are created at the expense of the gravitational energy through an
irreversible process whereas the scalar field is supposed to interact only with
itself and to be minimally coupled with the gravitational field. The
irreversible processes of particle creation are related to the non-equilibrium
pressure within the framework of the extended (causal or second-order)
thermodynamic theory. The scalar field (inflaton or tachyon) is described by an
exponential potential density added by a parameter which represents its
asymptotic value and can be interpreted as the vacuum energy. This model can
simulate three phases of the acceleration field of the Universe, namely,(a) an
inflationary epoch with a positive acceleration followed by a decrease of the
acceleration field towards zero, (b) a past decelerated period where the
acceleration field decreases to a maximum negative value followed by an
increase towards zero, and (c) a present accelerated epoch. For the energy
densities there exist also three distinct epochs which begin with a scalar
field dominated period followed by a matter field dominated epoch and coming
back to a scalar field dominated phase.Comment: 9 pages, 2 figures, to be published in General Relativity and
Gravitatio
Enhancing urban analysis through lacunarity multiscale measurement
Urban spatial configurations in most part of the developing countries showparticular urban forms associated with the more informal urban development ofthese areas. Latin American cities are prime examples of this sort, butinvestigation of these urban forms using up to date computational and analyticaltechniques are still scarce. The purpose of this paper is to examine and extendthe methodology of multiscale analysis for urban spatial patterns evaluation. Weexplain and explore the use of Lacunarity based measurements to follow a lineof research that might make more use of new satellite imagery information inurban planning contexts. A set of binary classifications is performed at differentthresholds on selected neighbourhoods of a small Brazilian town. Theclassifications are appraised and lacunarity measurements are compared in faceof the different geographic referenced information for the same neighbourhoodareas. It was found that even with the simple image classification procedure, animportant amount of spatial configuration characteristics could be extracted withthe analytical procedure that, in turn, may be used in planning and other urbanstudies purposes
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