571 research outputs found
Charge and CP symmetry breaking in two Higgs doublet models
We show that, for the most generic model with two Higgs doublets possessing a
minimum that preserves the symmetry, charge breaking (CB) cannot
occur. If CB does not occur, the potential could have two different minima, and
there is in principle no general argument to show which one is the deepest. The
depth of the potential at a stationary point that breaks CB or CP, relative to
the preserving minimum, is proportional to the squared mass of the
charged or pseudoscalar Higgs, respectively
Integro-differential IBVP versus differential IBVP: stability analysis
The aim of this paper is the qualitative analysis from theoretical and
numerical points of view of an integro-di erential initial boundary value problem
where the reaction term presents a certain memory e ect. Stability results are
established in both cases. As in certain cases the integro-di erential initial boundary value problem can be seen as a di erential initial boundary value problem,
the results obtained for the integro-di erential formulation are compared with the
correspondent results stated for the di erential initial boundary value problem. Numerical results illustrating the theoretical results are also included
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Integration of touch attention mechanisms to improve the robotic haptic exploration of surfaces
This text presents the integration of touch attention mechanisms to improve the efficiency of the action-perception loop, typically involved in active haptic exploration tasks of surfaces by robotic hands. The progressive inference of regions of the workspace that should be probed by the robotic system uses information related with haptic saliency extracted from the perceived haptic stimulus map (exploitation) and a “curiosity”-inducing prioritisation based on the reconstruction's inherent uncertainty and inhibition-of-return mechanisms (exploration), modulated by top-down influences stemming from current task objectives, updated at each exploration iteration. This work also extends the scope of the top-down modulation of information presented in a previous work, by integrating in the decision process the influence of shape cues of the current exploration path. The Bayesian framework proposed in this work was tested in a simulation environment. A scenario made of three different materials was explored autonomously by a robotic system. The experimental results show that the system was able to perform three different haptic discontinuity following tasks with a good structural accuracy, demonstrating the selectivity and generalization capability of the attention mechanisms. These experiments confirmed the fundamental contribution of the haptic saliency cues to the success and accuracy of the execution of the tasks
A software defined radio based anti-UAV mobile system with jamming and spoofing capabilities
The number of incidents between unmanned aerial vehicles (UAVs) and aircrafts at airports
and airfields has been increasing over the last years. To address the problem, in this paper we describe a portable system capable of protecting areas against unauthorized UAVs, which is based on the use of low-cost SDR (software defined radio) platforms. The proposed anti-UAV system supports target localization and integrates effective jamming techniques with the generation of global positioning system (GPS) spoofing signals aimed at the drone. Real-life tests of the implemented prototype have shown that the proposed approach is capable of stopping the reliable reception of radionavigation signals and can also divert or even take control of unauthorized UAVs, whose flight path depends on
the information obtained by the GPS system.info:eu-repo/semantics/publishedVersio
Aneurismas Gigantes do Septo Interauricular Simulando Massas Quísticas. Dois Casos com Opções Terapêuticas Diferentes
With the recent technical improvement in echocardiography imaging (second harmonics) the number of interatrial septum aneurysms (ASA) increased and are easily recognized. We assist to an overdiagnosing number of cases and diagnostic criteria emerged to face this problem. In the great majority of the cases ASA are small and inoffensive, but as ASA is considered a risk factor for cardioembolism when associated with persistence of foramen oval (PFO), an examination by transesophageal echocardiography (TEE) for exclusion of PFO makes the sense and is a common testing in patients with cryptogenic stroke. Besides these frequent ASA, other forms exist; the authors describe two cases of uncommon and huge ASA, one mimicking a right atrial tumor and the other a quistic, hipoechoic mass. The first case was associated with mitral stenosis and was submitted to surgery and the second was closed with an Amplatzer occluder device usually used in atrial septal defect (ASD)
Nocardial Endocarditis after Mitral Valve Replacement: Case Report and Review of the Literature
A Nocardia é responsável por diversos tipos de infecção quer em receptores imunocompetentes, quer imunocomprometidos e pode afectar qualquer órgão. A endocardite a Nocardia spp é muito rara e tem mau prognóstico. Segundo o nosso conhecimento e após revisão da literatura, foram reportados apenas 12 casos de endocardite a Nocardia, a maioria tratada com substituição valvular. Reportamos o primeiro caso descrito em Portugal de endocardite protésica a Nocardia, tratado com sucesso apenas com terapêutica antimicrobiana (trimetoprimsulfametoxazol), sem necessidade de substituição valvular
Loeffler Endocarditis in a Patient with Non-Hodgkin's Lymphoma
info:eu-repo/semantics/publishedVersio
Pierwotny Mięsak Naczyniowy Osierdzia. Opis Przypadku i Przegląd Piśmiennictwa
Primary cardiac tumours are rare entities and angiosarcoma is the most frequent primary cardiac malignant tumour. Mean
survival is six months and the tumour responds poorly to chemotherapy. We present the case of a 50 year-old patient with
localised pericardial angiosarcoma who survived 23 months after diagnosis with a combined approach of chemotherapy and
surgery
Left Atrial Volume: an Old Echocardiographic Measure with Renewed Prognostic Significance: a Study in Patients with Dilated Cardiomyopathy
Recentemente, surgiram alguns trabalhos que
ressaltaram a importância do cálculo do
volume da aurícula esquerda (VAE) como um
marcador de eventos cardíacos adversos. Foi
objectivo deste estudo avaliar a importância
prognóstica deste parâmetro em doentes (dts)
com deficiente função ventricular esquerda e
correlacioná-lo com outros parâmetros
clássicos de prognóstico – consumo de O2
(VO2 max) e pro-BNP (pBNP).
Métodos: Analisou-se o volume da aurícula
esquerda (VAE) por método de Simpson, numa população de 35 dts com cardiopatia dilatada (idiopática e isquémica) com fracção de ejecção (FE) 31±9,6% doentes (dts) eram de sexo masculino e a média de idades foi de
50,5±10,5 anos. Toda a população efectuou
estudos de ecocardiografia convencional
(incluindo avaliação por M-mode, bidimensional e Doppler), prova cardiorespiratória (VO2max) e doseamento de
pro-BNP. O tempo médio de seguimento foi de
24 ± 4 meses, tendo-se considerado como
eventos cardíacos (EC): internamento por
insuficiência cardíaca, transplante e morte.
Resultados: Dos parâmetros da ecocardiografia
- o diâmetro da AE foi de 46,6±5,7mm, as dimensões do VE em diástole – 73,5±10mm e
em sístole -58,9±11mm, a média da fracção
de ejecção foi de 31±9,6%, o VAE foi de
78,6±33 ml, os volumes do VE foram de
214±82ml em diástole e de 153±75ml em
sístole, 15 dts tinham padrão restritivo de
enchimento ventricular (E/A>2), a média da
área (Doppler cor) da insuficiência mitral foi de 4±3,3cm2, 14 dts tinham E/E’>15. O VO2
max médio foi de 20±5,8ml/kg/min e o pro-BNP de 3146±4629pg/mL. Para além da correlação de outros parâmetros clássicos ecocardiográficos com o prognóstico (volumes
VE, FE e E/E’), o VAE e o volume indexado
da AE (VAE/SC) mostraram uma correlação
com o prognóstico (EC) com r=0,4 (p=0,02)
que não se verificou para o diâmetro da AE
(p=ns). Em relação à tolerância ao esforço,
houve uma correlação inversa entre o diâmetro, o volume e o volume indexado da
AE e o VO2max, com maior significado
estatístico para o VAE e VAE/SC com
r=-0,48, p=0,008. Quanto ao pro-BNP, quer o
diâmetro, quer o VAE (ou volume indexado)
tiverem o mesmo nível de significado
estatístico (r=0,43; p=0,02). O valor predictivo de eventos (curvas ROC) para o VAE foi de 70ml e de 37ml/m2 para o VAE/m2.
Conclusão: O volume da aurícula esquerda/volume indexado é um parâmetro
ecocardiográfico com significado prognóstico
em dts com deficiente função ventricular
esquerda, correlacionando-se com a tolerância
ao esforço e pro-BNP
- …