7,108 research outputs found
On the number of nonequivalent propelinear extended perfect codes
The paper proves that there exist an exponential number of nonequivalent
propelinear extended perfect binary codes of length growing to infinity.
Specifically, it is proved that all transitive extended perfect binary codes
found by Potapov are propelinear. All such codes have small rank, which is one
more than the rank of the extended Hamming code of the same length. We
investigate the properties of these codes and show that any of them has a
normalized propelinear representation
HYPERTHYROIDISM AND PREGNANCY
Os autores descrevem as etiologias mais frequentes
do hipertiroidismo que ocorre na gravidez e referem
as alterações imunológicas que caracterizam a
doença de Graves e a tolerância imunológica
associada à gravidez. Referem o quadro clínico, o
diagnóstico laboratorial e o tratamento a efectuar.
Como o tratamento médico é o mais frequente,
referem os antitiroideus de síntese, suas
características e a opção mais conveniente para o
tratamento durante a gravidez. The authors describe most common
hyperthyroidism aetiologies that occur during
pregnancy and also the immunity changes that
define Graves disease and the immunity tolerance
associated to pregnancy. They also refer the clinical
pictur, laboratorial diagnosis and the treatment to be
carried out. Medical treatment is mostly based on
anti-thyroid drugs. Their characteristics and use
during pregnancy are discussed
Field sources in a Lorentz symmetry breaking scenario with a single background vector
This paper is devoted to investigating the interactions between stationary
sources of the electromagnetic field, in a model which exhibits explicit
Lorentz-symmetry breaking due to the presence of a single background vector. We
focus on physical phenomena that emerge from this kind of breaking and which
have no counterpart in Maxwell Electrodynamics
Cutaneous side effects of diabetes treatment
As lesões cutâneas são frequentes na diabetes mellitus, havendo um envolvimento da pele em cerca de 30 a 91% dos
doentes durante o curso da doença. Estas podem ser não infeciosas ou autoimunes, infeciosas ou resultar de complicações
do tratamento da diabetes, pelo uso de insulina ou outros antidiabéticos.
O crescente aumento na prevalência da diabetes mellitus tipo 2 e o advento, na última década, de novos antidiabéticos
orais e injetáveis com diferentes mecanismos celulares de atuação, justificam não só uma adequada orientação técnica sobre
a sequência de introdução de cada classe terapêutica, como o reconhecimento dos seus efeitos laterais, nomeadamente even-
tuais reações cutâneas adversas. A resolução destas dermatoses passa pela substituição farmacológica ou pelo aumento da
rotatividade do local onde se administra a insulina.
Os autores apresentam uma revisão da abordagem terapêutica da diabetes mellitus tipo 2, dando especial destaque às
possíveis reações cutâneas adversas aos hipoglicemiantes que hoje em dia temos ao nosso dispor.
A pesquisa bibliográfica foi realizada através de ferramentas eletrónicas de pesquisa avançada e não avançada das seguintes
fontes de dados: PubMed e Cochrane Library. Os artigos citados foram considerados os mais relevantes.info:eu-repo/semantics/publishedVersio
Developing a site-conditions map for seismic hazard Assessment in Portugal
The evaluation of site effects on a broad scale is a critical issue for seismic hazard and risk assessment, land use planning and emergency planning. As characterization of site conditions based on the shear-wave velocity has become increasingly important, several methods have been proposed in the literature to estimate its average over the first thirty meters (Vs30) from more extensively available data. These methods include correlations with geologic-geographic defined units and topographic slope. In this paper we present the first steps towards the development of a site–conditions map for Portugal, based on a regional database of shear-wave velocity data, together with geological, geographic, and lithological information. We computed Vs30 for each database site and classified it according to the corresponding geological-lithological information using maps at the smallest scale available (usually 1:50000). We evaluated the consistency of Vs30 values within generalized-geological classes, and assessed the performance of expedient methodologies proposed in the literature
Imaging 3D seismic velocity along the seismogenic zone of Algarve region (southern Portugal)
The present seismic tomographic study is focused around Algarve region, in South of Portugal. To locate the seismic events and find the local velocity structure of epicentral area, the P and S arrival times at 38 stations are used. The data used in this study were obtained during the Algarve campaign which worked from January/2006 to July/2007. The preliminary estimate of origin times and hypocentral coordinates are determined by the Hy- poinverse program. Linearized inversion procedure was applied to comprise the following two steps: 1) finding the minimum 1D velocity model using Velest and 2) simultaneous relocation of hypocenters and determination of local velocity structure. The velocity model we have reached is a 10 layer model which gave the lowest RMS, after several runnings of eight different velocity models that we used “a priori”. The model parameterization assumes a continuous velocity field between 4.5 km/s and 7.0 km/s until 30 km depth. The earth structure is represented in 3D by velocity at discrete points, and velocity at any intervening point is determined by linear interpolation among the surrounding eight grid points. A preliminary analysis of the resolution capabilities of the dataset, based on the Derivative Weight Sum (DWS) distribution, shows that the velocity structure is better resolved in the West part of the region between the surface to15 km. The resulting tomographic image has a prominent low-velocity anomaly that shows a maximum decrease in P-wave velocity in the first 12 kms in the studied region. We also identified the occurrence of local seismic events of reduced magnitude not catalogued, in the neighbourhood of Almodôvar (low Alentejo). The spatial distribution of epicentres defines a NE-SW direction that coincides with the strike of the mapped geological faults of the region and issued from photo-interpretation. Is still expectable to refine the seismicity of the region of Almodôvar and establish more rigorously its role in the seismotectonic picture of the region. This work is expected to produce a more detailed knowledge of the structure of the crust over the region of Algarve, being able to identify seismogenic zones, potentially generators of significant seismic events and also the identification of zones of active faults
Modeling electrodialysis and a photochemical process for their integration in saline wastewater treatment.
Oxidation processes can be used to treat industrial wastewater containing non-biodegradable organic compounds. However, the presence of dissolved salts may inhibit or retard the treatment process. In this study, wastewater desalination by electrodialysis (ED) associated with an advanced oxidation process (photo-Fenton) was applied to an aqueous NaCl solution containing phenol. The influence of process variables on the demineralization factor was investigated for ED in pilot scale and a correlation was obtained between the phenol, salt and water fluxes with the driving force. The oxidation process was investigated in a laboratory batch reactor and a model based on artificial neural networks was developed by fitting the experimental data describing the reaction rate as a function of the input variables. With the experimental parameters of both processes, a dynamic model was developed for ED and a continuous model, using a plug flow reactor approach, for the oxidation process. Finally, the hybrid model simulation could validate different scenarios of the integrated system and can be used for process optimization
Generation of higher derivatives operators and electromagnetic wave propagation in a Lorentz-violation scenario
We study the perturbative generation of higher-derivative operators as
corrections to the photon effective action, which are originated from a Lorentz
violation background. Such corrections are obtained, at one-loop order, through
the proper-time method, using the zeta function regularization. We focus over
the lowest order corrections and investigate their influence in the propagation
of electromagnetic waves through the vacuum, in the presence of a strong,
constant magnetic field. This is a setting of experimental relevance, since it
bases active efforts to measure non linear electromagnetic effects. After
surprising cancellations of Lorentz violating corrections to the Maxwell's
equation, we show that no effects of the kind of Lorentz violation we consider
can be detected in such a context.Comment: v2: 13 pages, no figures, section IV considerably rewritten, main
results unchanged and are now obtained in a simpler way. To appear in PL
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