559 research outputs found
Notas para una filosofía de la creencia
El ser humano habita en un suelo frágil y resbaladizo, al que se atiene en unos u otros momentos en virtud de las creencias que lo sostienen. El reconocimiento básico de la creencia como el peculiar ámbito en el que nos movemos y existimos implica situar a la persona en toda su hondura como realidad relativamente absoluta que, más allá del escepticismo y del dogmatismo, domicilia su existencia en unas creencias que le permiten seguir siendo. En el presente estudio presentamos las notas iniciales de una filosofía de la creencia a partir de la filosofía personalista de Jean Lacroix y del diálogo con otros pensadores como Ortega y Jaspers
Finitness of the basic intersection cohomology of a Killing foliation
We prove that the basic intersection cohomology where is the singular
foliation determined by an isometric action of a Lie group on the compact
manifold , is finite dimensional
Tautness for riemannian foliations on non-compact manifolds
For a riemannian foliation on a closed manifold , it is
known that is taut (i.e. the leaves are minimal submanifolds) if
and only if the (tautness) class defined by the mean curvature form
(relatively to a suitable riemannian metric ) is zero. In the
transversally orientable case, tautness is equivalent to the non-vanishing of
the top basic cohomology group , where n = \codim
\mathcal{F}. By the Poincar\'e Duality, this last condition is equivalent to
the non-vanishing of the basic twisted cohomology group
, when is oriented. When is
not compact, the tautness class is not even defined in general. In this work,
we recover the previous study and results for a particular case of riemannian
foliations on non compact manifolds: the regular part of a singular riemannian
foliation on a compact manifold (CERF).Comment: 18 page
Estructura, fábrica magnética y emplazamiento de los granitos de Brealito y La Paya, basamento del valle Calchaquí, Salta, Argentina
The Brealito and La Paya granitoids are elliptical-shaped plutons with N-S elongation. They intrude into the Puncoviscana and La Paya Formations, respectively. The internal structure of these plutons has been studied by using field structures and applying the Anisotropy of the Magnetic Susceptibility (AMS). The magnetic fabric of the La Paya pluton reflects the orientation of biotite, the main paramagnetic mineral in this granite (K between 1.9 and 6.7 x10-5SI). Instead, the magnetic behavior of the Brealito granite is more complex since not only paramagnetic minerals, but also the ferromagnetic contribution (K between 22 and 466 x10-5SI) of magnetite crystals strongly control the magnetic fabric of some samples. Total anisotropy values of the magnetic fabrics are coherent with the magmatic nature of the analized samples. From the structural point of view, both plutons display similarities. These granites are lozenge-shaped bodies concordant with the host rocks. Their planar fabrics are mainly NS-trending and West dipping, and magnetic lineations plunge at low angles along the N-S direction
Petrology and structure of Campanario-La Haba pluton and Los Berrocales stock (Badajoz): preliminary dates
[Abstract] The Campanario-La Haba pluton and Los Berrocales stock are situated in the southern part ofthe Central-Iberian zone. They form part ofthe late-Hercynian alignement named Caceres-Linares or Pedroches-Alburquerque. During the last years these two granitoids have been related, based on spatial and/or genetic criteria, with Los Pedroches Batholith. These igneous bodies are different. Campanario-La Haba pluton is a coarse grained peraluminous granite with large megaphenocrysts ofcordierite. Three facies are differenciated based on petrographic criteria: coarse grained porfiric granite with megaphenocryst of cordierite, fine grained porfiric granite with megaphenocryst of cordierire and fine-medium granite. Los Berrocales is a zoned stock formed by granodiorites graded to granites in the center. Structure-studies indicates that the Campanario-La Haba pluton has been structurated in magmatic state. The magmatic foliation and lineation direction show the orientation ofN12üE, parallel to the pluton lenghtening. The magnetic susceptibility values show that the magnetic behaviour of the granites is dominated by paramagnetic minerals, fine for apply the Anisotropy ofthe Magnetic Susceptibility. The magnetic structure is rather homogeneous and the magnetic lineation and foliation show the N12üE direction.
This paper shows premier dates and conclusions of the work that Mineralogy and Petrology department (University of Basque Country) has being done in
conjunction with the Geodinamic department (University ofBasque Country)
on the westhern end of the Los Pedroches Batholith
Revisiting the -Love- relations for superfluid neutron stars
We study the tidal problem and the resulting -Love- approximate
universal relations for rotating superfluid neutron stars in the Hartle-Thorne
formalism. Superfluid stars are described in this work by means of a two-fluid
model consisting of superfluid neutrons and all other charged constituents. We
employ a stationary and axisymmetric perturbation scheme to second order around
a static and spherically symmetric background. Recently, we used this scheme to
study isolated rotating superfluid stars. In this paper it is applied to
analyze the axially symmetric sector of the tidal problem in a binary system.
We show that a consistent use of perturbative matching theory amends the
original two-fluid formalism for the tidal problem to account for the possible
non-zero value of the energy density at the boundary of the star. This is
exemplified by building numerically different stellar models spanning three
equations of state. Significant departures from universality are found when the
correct matching relations are not taken into account. We also present an
augmented set of universal relations for superfluid neutron stars which
includes the contribution to the total mass of the star at second order,
. Therefore, our results complete the set of universal relations for
rotating superfluid stars, generalizing our previous findings in the perfect
fluid case.Comment: 18 pages, 3 figures. Reference added, typos and minor corrections,
and some discussion expanded, to agree with the published versio
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Ganglion-specific splicing of TRPV1 underlies infrared sensation in vampire bats.
Vampire bats (Desmodus rotundus) are obligate blood feeders that have evolved specialized systems to suit their sanguinary lifestyle. Chief among such adaptations is the ability to detect infrared radiation as a means of locating hotspots on warm-blooded prey. Among vertebrates, only vampire bats, boas, pythons and pit vipers are capable of detecting infrared radiation. In each case, infrared signals are detected by trigeminal nerve fibres that innervate specialized pit organs on the animal's face. Thus, vampire bats and snakes have taken thermosensation to the extreme by developing specialized systems for detecting infrared radiation. As such, these creatures provide a window into the molecular and genetic mechanisms underlying evolutionary tuning of thermoreceptors in a species-specific or cell-type-specific manner. Previously, we have shown that snakes co-opt a non-heat-sensitive channel, vertebrate TRPA1 (transient receptor potential cation channel A1), to produce an infrared detector. Here we show that vampire bats tune a channel that is already heat-sensitive, TRPV1, by lowering its thermal activation threshold to about 30 °C. This is achieved through alternative splicing of TRPV1 transcripts to produce a channel with a truncated carboxy-terminal cytoplasmic domain. These splicing events occur exclusively in trigeminal ganglia, and not in dorsal root ganglia, thereby maintaining a role for TRPV1 as a detector of noxious heat in somatic afferents. This reflects a unique organization of the bat Trpv1 gene that we show to be characteristic of Laurasiatheria mammals (cows, dogs and moles), supporting a close phylogenetic relationship with bats. These findings reveal a novel molecular mechanism for physiological tuning of thermosensory nerve fibres
Deterioro cognitivo en la esclerosis múltiple
Amongst the varied symptomology of multiple
sclerosis is to be fo und the alteration of higher
functions (cognitive deficit), which has considerable
repercussions on the quality of life of patients.
The old descriptions of the disease rarely
differentiate cognitive affectation from the more general
category of “mental symptoms”, which also includes a
broad range of affective disorders. Towards 1960
neuropsychological tests began to be employed, and it
was from the 1970s onwards that a clear distinction was
drawn between deterioration of the higher functions
and psycho-affective aspects in the disease.
The pattern of cognitive deterioration in patients
with multiple sclerosis is not uniform. During the initial
phases of the disease it is, in general, light and it has an
insidious start, although inter-individual variability is
wide, depending on the predominant pathological
alterations in the lesions and on their number and
localisation. In more severe cases, it is possible to
include within the debatable term of subcortical
dementia, intellectual slowness, problems of attention,
alterations in abstract reasoning, shortcomings in the
resolution of problems and memory dysfunction.
It is an almost invariable complication of the
advanced stages of the disease, since the lesions
characterised by axonal loss affect broad areas of
white matter, which determines the deafferentation of
several areas of cortical association.
There does not appear to be any correlation
between cognitive deterioration and the variables of
the disease considered in an independent way, such as
demographic data, clinical course, alterations of mood,
consumption of medicines or fatigue. Although,
evidently, the disease’s progressive secondary forms
of greater duration and the accumulation of lesions are
what present the greatest deterioration.
With present-day techniques of neuroimaging it
has been possible to show a correlation between
cognitive deterioration and the existence of an
increase in ventricular size, periventricular lesions and
atrophy of the callous body
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