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Search Results: 1 - 10 of 134910 matches for " Jo?o Batista Destro Filho "
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On the Blind Estimation of Baud-Rate Equalizer Performance
Joo-Batista Destro-Filho
EURASIP Journal on Advances in Signal Processing , 2003, DOI: 10.1155/s1687617202209063
Abstract: This paper proposes a new method for carrying out joint blind equalization and blind estimation of the bit-error-rate (BER) in the output of baud-rate FIR equalizers. A simple test for assessing decision errors in the output of the decision device is derived. A comparative study of several BER estimator methods is presented in terms of convergence rate and tracking capability of both static and dynamic channels. Simulations not only validate theoretical results but also point out the effectiveness of the new proposition in terms of low computational burden and accurate BER estimation. Finally, an application of the new proposition for the detection and correction of misconvergence due to local minima issues is also presented.
Simula o do campo elétrico e magnético de um canal i nico utilizando o software FEMM
Ricardo de Camargos Lopes,Rafael Leal Lima,Vanessa Pereira Gomes,Joo Batista Destro Filho
Exacta , 2010,
Abstract: This work presents a simulation study of the behavior of electric and magnetic fields on calcium ion channels through a simple model. The study considers a situation of resting potential at the ion channel, involving computer simulations, using the software Finite Element Method Magnetics (FEMM), which calculates these fields by finite element technique. On these simulations we can see how these fields behave along the channels, and from that understand better its normal and pathological behavior in the future. From these simulations it was concluded that the electric field is approximately constant along the channel, with a magnitude of at about 107[volts/meter], while the electrical potential varied linearly with the height. In terms of the magnetic field, it grows exponentially in the radial direction until the end of the pore, reaching its maximum (about 4.10-9[tesla]), and decreases rapidly from this point.
Análise de registros eletrocardiográficos associados ao infarto agudo do miocárdio
Mansur, Paulo Henrique Garcia;Cury, Lacordaire Kemel Pimenta;Destro-Filho, Joo Batista;Resende, Elmiro Santos;Destro, José Paulo Breda;Oliveira, Luana Michelli de;Moraes, Diego Carvalho Gomes de;Freitas, Geraldo Rubens Ramos de;Rocha, Lucila Soares da Silva;
Arquivos Brasileiros de Cardiologia , 2006, DOI: 10.1590/S0066-782X2006001500007
Abstract: objective: evaluate correlations between variations in eletrocardiogram (ecg) recordings and acute myocardial infarction. methods: use of a low-cost software to digitalize printed and/or ".pdf" file format ecg recordings. calculation of st-segment area and amplitudes of the j and y points. results: the amplitude of the y point holds maximum correlation with troponin concentration. st-segment elevation is not a good statistical indicator of myocardial infarction severity. there is a strong negative correlation between the amplitude of the j point and the amount of magnesium ions, but no statistical correlation with sodium or calcium ions. neither method for calculating the st-segment area (pixel counts and interpolation) indicated any significant differences in the results. conclusion: the software used proved to be functional and cost-effective. y point amplitude is a sensitive marker of myocardial infarction, and is also a calculation method both simpler to use and less subject to error than the calculation of the st-segment elevation area.
Quantitative Estimation of the Nonstationary Behavior of Neural Spontaneous Activity
Joo-Batista Destro-Filho,Carlos-Alberto Estombelo-Montesco,Luiz-Otavio Murta-Junior,Sergio Martinoia,Michela Chiappalone,Suelen Moreira-Marques,Amanda F. Neves
Computational Intelligence and Neuroscience , 2010, DOI: 10.1155/2010/785919
Abstract: The “stationarity time” (ST) of neuronal spontaneous activity signals of rat embryonic cortical cells, measured by means of a planar Multielectrode Array (MEA), was estimated based on the “Detrended Fluctuation Analysis” (DFA). The ST is defined as the mean time interval during which the signal under analysis keeps its statistical characteristics constant. An upgrade on the DFA method is proposed, leading to a more accurate procedure. Strong statistical correlation between the ST, estimated from the Absolute Amplitude of Neural Spontaneous Activity (AANSA) signals and the Mean Interburst Interval (MIB), calculated by classical spike sorting methods applied to the interspike interval time series, was obtained. In consequence, the MIB may be estimated by means of the ST, which further includes relevant biological information arising from basal activity. The results point out that the average ST of MEA signals lies between 2-3 seconds. Furthermore, it was shown that a neural culture presents signals that lead to different statistical behaviors, depending on the relative geometric position of each electrode and the cells. Such behaviors may disclose physiological phenomena, which are possibly associated with different adaptation/facilitation mechanisms. 1. Introduction The digital processing of biological signals may be considered a challenging task [1], due to the underlying characteristics of such systems and signals: the nonlinearity, which is closely connected with the complex behavior of the alive organisms [2, 3]; and the nonstationarity of the time series [4]. A classical mathematical procedure in neuronal signal processing consists of the detection of spikes connected with action potentials, which requires the establishment of an amplitude threshold, above which any potential is considered a spike [5]. The next step is devoted to the estimation of the “Interspike Interval” (ISI) time series, including spike classification [6], which enables several analyses in the field of neuronal coding [3]. Notice that spike classification is based on pattern recognition theory, involving tools such as Mahalanobis minimum distance [6, 7] and Independent Component Analysis [5]. In addition, neural connectivity [8] is also a very important research field, based on the application of cross-correlation theory [9–12] and spectral coherence [13] to the ISI time series, in order to evaluate the network of synaptic connections among cells within the cultured tissue. All these signal processing techniques are based on the concept of “ISI time series” [8], the estimation
Democracia representativa e or amento participativo:governan a e accountability
Joo Batista Domingues Filho
Revista Sociedade & Natureza , 2004,
Abstract: Argument about the difficulties regarding the relation between creativity institucional and the trial decided in the iterior from the representative democracy. For so much, is carried out a reflection about the possible virtuosity on the accasion of tha operation from the state with accountability. Finally, the plurality model arises like theoretical too for the comprehension from the interaction between representative democracy and budget participativo.
Cerebrospinal fluid syndromes in HIV-positive patients with acute consciousness compromise
Batista, Marcus Sabry Azar;Sesso, Ricardo C.C.;Reis-Filho, Joo Batista dos;
Revista da Sociedade Brasileira de Medicina Tropical , 1999, DOI: 10.1590/S0037-86821999000600011
Abstract: we reviewed the cerebrospinal fluid (csf) syndromes of 100 consecutive hiv-positive patients presenting acute consciousness compromise in emergency rooms, and correlated them with clinical data. the most frequent csf syndromes were: absolute protein-cytological dissociation (21), viral (19), neurocryptococcosis (7), relative protein-cytological dissociation (6) and septic (4), moderate hypoglycorrachia (4), severe hypoglycorrachia (4) and hydroelectrolytic disturbance (3). one fifth of the patients had csf syndromes considered sufficient for diagnosis or an immediate clinical decision. the most common clinical data were infective and neurological. there was little correlation between the clinical data and the csf syndromes. we conclude that in hiv-positive individuals presenting acute consciousness disturbances there are frequently non-specific results in the csf analysis that must be weighed against a detailed history and thorough physical examination. taking this into account, in about one fifth of cases the csf analysis can offer useful information for treatment.
Cerebrospinal fluid syndromes in HIV-positive patients with acute consciousness compromise
Batista Marcus Sabry Azar,Sesso Ricardo C.C.,Reis-Filho Joo Batista dos
Revista da Sociedade Brasileira de Medicina Tropical , 1999,
Abstract: We reviewed the cerebrospinal fluid (CSF) syndromes of 100 consecutive HIV-positive patients presenting acute consciousness compromise in emergency rooms, and correlated them with clinical data. The most frequent CSF syndromes were: absolute protein-cytological dissociation (21), viral (19), neurocryptococcosis (7), relative protein-cytological dissociation (6) and septic (4), moderate hypoglycorrachia (4), severe hypoglycorrachia (4) and hydroelectrolytic disturbance (3). One fifth of the patients had CSF syndromes considered sufficient for diagnosis or an immediate clinical decision. The most common clinical data were infective and neurological. There was little correlation between the clinical data and the CSF syndromes. We conclude that in HIV-positive individuals presenting acute consciousness disturbances there are frequently non-specific results in the CSF analysis that must be weighed against a detailed history and thorough physical examination. Taking this into account, in about one fifth of cases the CSF analysis can offer useful information for treatment.
Comparative Skill of Numerical Weather Forecasts in Eastern Amazonia  [PDF]
Bergson Cavalcanti de Moraes, Douglas Batista da Silva Ferreira, Luiz Gylvan Meira Filho, Juarez Ventura de Oliveira, Everaldo Barreiros de Souza, Pedro Pereira Ferreira Júnior, Renata Kelen Cardoso Camara, Edson José P. da Rocha, Joo Batista M. Ribeiro
Atmospheric and Climate Sciences (ACS) , 2013, DOI: 10.4236/acs.2013.33037
Abstract:

The present study evaluates the performance of three numerical weather forecasting models: Global Forecast System (GFS), Brazilian Regional Atmospheric Modelling System (BRAMS) and ETA Regional Model (ETA), by means of the Mean Error (ME) and the Root Mean Square Error (RMSE), during the most rainy four months period (January to April 2012) on Eastern Amazonia. The models displayed errors of superestimation and underestimation with respect to the observed precipitation, mainly over center-north of Pará and all of Amapá, where the precipitation is higher. Among the analyzed models, GFS shows the best performance, except during January and March, when the model to underestimated precipitation, possibly due to the anomalously high values recorded.

Maturidade fisiológica e germina??o de sementes de macela (Egletes viscosa (L.) Less.) submetidas à secagem
Bezerra, Antonio Marcos E.;Medeiros Filho, Sebasti?o;Freitas, Joo Batista S.;
Horticultura Brasileira , 2003, DOI: 10.1590/S0102-05362003000300026
Abstract: the influence of harvesting date and the effects of drying on the physiological quality of macela seeds was evaluated. the harvesting dates of 93; 100; 107; 114; 121; 128 and 135 days after transplanting (dat) were evaluated. half volume of the harvested seeds was taken to a dryer (40oc for 72 h), while the other half was packed in plastic bags and stored in a cold room (20oc) during the same period. a complete randomized design in a 2 x 7 factorial, with four repetitions, was used. the seeds reached the physiological maturity about 121-128 dat. the drying process had no influence on the macela seeds physiologic quality.
Prediction of transients and control reactions in a transonic wind tunnel
Falc?o Filho, Joo Batista Pessoa;Ortega, Marcos Aurélio;Góes, Luiz Carlos Sandoval;
Journal of the Brazilian Society of Mechanical Sciences , 2000, DOI: 10.1590/S0100-73862000000200014
Abstract: this work describes a lumped parameter mathematical model for the prediction of transients in an aerodynamic circuit of a transonic wind tunnel. control actions to properly handle those perturbations are also assessed. the tunnel circuit technology is up to date and incorporates a novel feature: high-enthalpy air injection to extend the tunnel?s reynolds number capability. the model solves the equations of continuity, energy and momentum and defines density, internal energy and mass flow as the basic parameters in the aerodynamic study as well as mach number, stagnation pressure and stagnation temperature, all referred to test section conditions, as the main control variables. the tunnel circuit response to control actions and the stability of the flow are numerically investigated. initially, for validation purposes, the code was applied to the awt ("altitude wind tunnel" of nasa-lewis). in the sequel, the brazilian transonic wind tunnel was investigated, with all the main control systems modeled, including injection.
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