22,028 research outputs found
Phantom Black Holes in Einstein-Maxwell-Dilaton Theory
We obtain the general static, spherically symmetric solution for the
Einstein-Maxwell-dilaton system in four dimensions with a phantom coupling for
the dilaton and/or the Maxwell field. This leads to new classes of black hole
solutions, with single or multiple horizons. Using the geodesic equations, we
analyse the corresponding Penrose diagrams revealing, in some cases, new causal
structures.Comment: Latex file, 32 pages, 15 figures in eps format. Typo corrected in Eq.
(3.18
Molecular Evaluation of exons 8 and 22 of the SHANK3 gene in Autism Spectrum Disorders
Autism spectrum disorders are a group of neurodevelopmental disorders with a complex and heterogeneous etiology. Studies have shown that genetic factors play an important role in the aetiology of these diseases. Recently, de novo mutations, frameshifts and deletions have been described in the SHANK3 gene, also known as ProSAP2 gene, which encodes a synaptic scaffolding protein. All the participants of this study had normal karyotypes and underwent screening for Fragile-X syndrome. Subsequently, they were analyzed by direct sequencing of different points of exons 8 and 22 of the SHANK3 gene. None of the study participants presented with changes in these regions. These findings may be due to the fact that mutations, deletions and duplications of the SHANK3 gene are rare
Anatomical Study of the Accessory Head of the Flexor Pollicis Longus Muscle and its Relationship to the Anterior Interosseous Nerve in Brazilian Individuals
Indexación: Web of Science; Scielo.RESUMEN: Entre los sÃndromes de compresión nerviosa en el antebrazo, debido a la presencia de arcos tendinosos de músculos relacionados al trayecto de los nervios que transcurren entre sus capas musculares, se encuentra el del nervio interóseo anterior (NIA). La presencia de variaciones musculares puede generar arcos que ocasionan compresión nerviosa. El objetivo fue establecer la incidencia y morfologÃa del músculo accesorio del flexor largo del pulgar (AFLP) y la relación de éste con el NIA o sus ramos motores. Se utilizaron 30 antebrazos, de cadáveres formolizados de individuos adultos brasileños. El punto de referencia seleccionado para las mediciones fue el epicóndilo medial del humero (EMH). Se observó que tres miembros superiores presentaron el AFLP (10%), en todos ellos se originó en el EMH para terminar insertándose en el tendón del músculo flexor largo del pulgar (FLP). El vientre muscular presentó aspecto fusiforme, el cual tenÃa un tendón que formó un arco con el FLP. En uno de los casos, este arco se relacionó con el paso del NIA; en los otros dos, lo hizo con los ramos motores que se originan del NIA. Al diagnosticar los sÃndromes generados por compresión nerviosa se debe considerar la presencia del AFLP, el cual, potencialmente se puede relacionar con el trayecto del NIA o de sus ramos.SUMMARY: Between the syndromes of nerve compression in the forearm, due to the presence of the tendinous arches related to the nerves that pass between its muscle layers, is the anterior interosseous nerve (AIN). The presence of muscular variations can generate arches that cause nerve compression. The aim of our study was to establish the incidence and morphology of the accessory head of flexor pollicis longus muscle (AFPLm) and its relationship with AIN or its branches. Thirty forearms of formalized corpses of adult Brazilians were used. The selected landmark for measurements was the medial epicondyle of the humerus (MEH). It was noted that three upper limbs presented the AFPLm (10%), originated from the MEH to end inserted into the tendon of the flexor pollicis longus muscle. The AFPLm showed fusiform appearance, which had a tendon that formed an arch with the flexor pollicis longus muscle. In one case, this arch was associated with the passage of AIN. In the other two, this arch was related to motor branches originating from the AIN. The diagnosis of nerve compression syndromes should consider the presence of AFLPm, which potentially can be related to the course of the AIN or its branches.http://ref.scielo.org/yjjjr
Measuring the continuum polarization with ESPaDOnS
Our goal is to test the feasibility to obtain accurate measurements of the
continuum polarization from high-resolution spectra using the
spectropolarimetric mode of ESPaDOnS. We used the new pipeline OPERA to reduce
recent and archived ESPaDOnS data. A couple of standard polarization stars and
several science objects were tested for the linear mode. In addition, the
circular mode was tested using several objects from the archive with expected
null polarization. Synthetic broad-band polarization was computed from the
ESPaDOnS continuum polarization spectra and compared with published values
(when available) to quantify the accuracy of the instrument. The continuum
linear polarization measured by ESPaDOnS is consistent with broad-band
polarimetry measurements available in the literature. The accuracy in the
degree of linear polarization is around 0.2-0.3% considering the full sample.
The accuracy in polarization position angle using the most polarized objects is
better than 5deg. Consistent with this, the instrumental polarization computed
for the circular continuum polarization is also between 0.2-0.3%. Our results
suggest that measurements of the continuum polarization using ESPaDOnS are
viable and can be used to study many astrophysical objects.Comment: 15 pages, 13 figures, accepted to Astronomy and Astrophysic
Quantum corrections to gravity and their implications for cosmology and astrophysics
The quantum contributions to the gravitational action are relatively easy to
calculate in the higher derivative sector of the theory. However, the
applications to the post-inflationary cosmology and astrophysics require the
corrections to the Einstein-Hilbert action and to the cosmological constant,
and those we can not derive yet in a consistent and safe way. At the same time,
if we assume that these quantum terms are covariant and that they have relevant
magnitude, their functional form can be defined up to a single free parameter,
which can be defined on the phenomenological basis. It turns out that the
quantum correction may lead, in principle, to surprisingly strong and
interesting effects in astrophysics and cosmology.Comment: 15 pages, LaTeX, WS style, contribution to the Proceedings of the
QFEXT-2011 conference in the Centro de Ciencias de Benasque Pedro Pasqual,
Spai
Regional Income Convergence in Portugal (1991-2002)
Our research aims to address the problem of inequality in income distribution from a different perspective than the usual. We intend to verify if geography influences the pattern of inequality, that is, if the standard of living varies from region to region and if, in the process of growth, spatial units in Portugal have been converging in terms of most relevant variables, such as income. We search the answers to these questions by introducing the treatment of convergence between smaller territorial units, the municipalities as individuals. We intend to evaluate convergence or divergence in income growth and test empirically the theoretical hypothesis that β-convergence, although necessary, is not a sufficient condition for σ-convergence. To study convergence, we use information about GDP and wages for NUTS III regions, and wages for municipalities. We observe spatial dependence between municipalities, so we estimate spatial econometric models to test convergence. With regard to conditional convergence between municipalities, the model most appropriate is the one which includes in the explanatory variables the weight of primary sector employment, leading us to conclude that this variable distinguishes the "steady state" of the small economies. Variables like the activity rate and percentage of active population with higher education also reveal highly significant on the growth of wages, reflecting the different contexts of the labor market at regional level
Causalidade e transmissão de preços entre os nÃveis de mercados na cadeia do feijão em São Paulo.
O presente trabalho objetivou avaliar a causalidade e transmissão de preço entre os nÃveis de mercado da cadeia do feijão em São Paulo.CONAFE
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