2,086 research outputs found

    Effective extraction and filtering of frequency components in physiological signals using sum-of-sinusoids modelling

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    In biological signal processing, modelling and extraction of specific frequency components constitute an important procedure for filtering signal components of interest as well as artefact removal. Under some interference scenarios, a satisfactory elimination of artefacts from the signal must be even performed by subtraction of an artefact waveform model or template, rather than the use of linear band-pass filters. That is the case of the gradient artefact induced in the EEG within the fMRI scanner, which cannot be characterized by a specific bandwidth or spectral content. This paper presents a simple and accurate approach based upon sum-of-sinusoids modelling for signal and artefact frequency components representation in physiological signals. According to the proposed method, each signal frequency component is approximated as a sinusoid, whose amplitude and phase parameters are estimated by making use of the Discrete Fourier Transform (DFT). The proposed approach reveals to perform an effective modelling and extraction of ECG signal components as well as underlying gradient artefacts in the EEG signal

    Orthogonal basis with a conicoid first mode for shape specification of optical surfaces: Reply

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    We present some comments to the paper “Orthogonal basis with a conicoid first mode for shape specification of optical surfaces: comment.

    Credible Equilibria in Games with Utilities Changing During the Play

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    Whenever one deals with an interactive decision situation of long duration, one has to take into account that priorities of the participants may change during the conflict. In this paper we propose an extensive-form game model to handle such situations and suggest and study a solution concept, called credible equilibrium, which generalizes the concept of the Nash equilibrium. We also discuss possible variants to this concept and applications of the model to other types of games.

    Finite-size investigation of scaling corrections in the square-lattice three-state Potts antiferromagnet square-lattice three-state Potts antiferromagnet

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    We investigate the finite-temperature corrections to scaling in the three-state square-lattice Potts antiferromagnet, close to the critical point at T=0. Numerical diagonalization of the transfer matrix on semi-infinite strips of width LL sites, 4L144 \leq L \leq 14, yields finite-size estimates of the corresponding scaled gaps, which are extrapolated to LL\to\infty. Owing to the characteristics of the quantities under study, we argue that the natural variable to consider is xLe2βFortheextrapolatedscaledgapsweshowthatsquarerootcorrections,inthevariablex \equiv L e^{-2\beta}For the extrapolated scaled gaps we show that square-root corrections, in the variable x,arepresent,andprovideestimatesforthenumericalvaluesoftheamplitudesofthefirstandsecondordercorrectionterms,forboththefirstandsecondscaledgaps.WealsocalculatethethirdscaledgapofthetransfermatrixspectrumatT=0,andfindanextrapolatedvalueofthedecayofcorrelationsexponent,, are present, and provide estimates for the numerical values of the amplitudes of the first-- and second--order correction terms, for both the first and second scaled gaps. We also calculate the third scaled gap of the transfer matrix spectrum at T=0, and find an extrapolated value of the decay-of-correlations exponent, \eta_3=2.00(1).Thisisatoddswithearlierpredictions,totheeffectthatthethirdrelevantoperatorintheproblemwouldgive. This is at odds with earlier predictions, to the effect that the third relevant operator in the problem would give \eta_{{\bf P}_{\rm stagg}}=3$, corresponding to the staggered polarization.Comment: RevTex4, 5 pages, 2 .eps figures include

    Population Structure Of Jatropha And Its Implication For The Breeding Program

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    Jatropha (Jatropha curcas L.) has potential as an oilseed crop that requires the development of technology for its exploitation. The objective of this study was to assess the population structure and the genetic diversity in jatropha accessions at a global level using simple sequence repeat (SSR) molecular markers. Jatropha accessions (N = 109) from 10 countries were genotyped using 10 SSR markers. The results showed a low level of genetic diversity among 92 accessions originating from India, Mozambique, Ethiopia, Tanzania, Brazil, Honduras, and Indonesia, which were grouped in one cluster. In contrast, accessions from Mexico and Costa Rica showed high level of genetic variability. These accessions may be used to increase the genetic diversity of jatropha in the breeding populations. The study also showed the need of collecting activity from the center of diversity (Mexico and Costa Rica) to aggregate the genetic diversity in the international collections of jatropha. © FUNPEC-RP.15

    DOIS ANOS (LETIVOS) DE PANDEMIA: EXPECTATIVAS E RECEIOS DE NOVOS ESTUDANTES DO ENSINO SUPERIOR

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    A pandemia exacerbou os desafios enfrentados pelos estudantes que ingressam no ensino superior. Este estudo, de natureza qualitativa e cariz exploratório, teve como objetivo contribuir para o conhecimento das expectativas e dos receios de dois grupos de estudantes (n=90) que ingressaram no ensino superior durante a pandemia. Os dados foram recolhidos com recurso à versão portuguesa do Hopes and Fears Questionnaire. A análise dos resultados identificou diferenças ao nível das expectativas e dos receios dos estudantes inquiridos, nomeadamente nos domínios educação, global/coletivo e realização pessoal. Concluiu‐se que os estudantes expressaram mais receios do que expectativas em relação ao seu futuro. Este estudo contribui para um melhor conhecimento sobre a transição e adaptação ao Ensino Superior em contexto de pandemia COVID‐19.info:eu-repo/semantics/publishedVersio

    Predicted Planck Extragalactic Point Source Catalogue

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    An estimation of the number and amplitude (in flux) of the extragalactic point sources that will be observed by the Planck Mission is presented in this paper. The study is based on the Mexican Hat wavelet formalism introduced by Cayon et al. 2000. Simulations at Planck observing frequencies are analysed, taking into account all the possible cosmological, Galactic and Extragalactic emissions together with noise. With the technique used in this work the Planck Mission will produce a catalogue of extragalactic point sources above fluxes: 1.03 Jy (857 GHz), 0.53 Jy (545 GHz), 0.28 Jy (353 GHz), 0.24 Jy (217 GHz), 0.32 Jy (143 GHz), 0.41 Jy (100 GHz HFI), 0.34 Jy (100 GHz LFI), 0.57 Jy (70 GHz), 0.54 Jy (44 GHz) and 0.54 Jy (30 GHz), which are only slightly model dependent (see text). Amplitudes of these sources are estimated with errors below 15%. Moreover, we also provide a complete catalogue (for the point sources simulation analysed) with errors in the estimation of the amplitude below 10%. In addition we discuss the possibility of identifying different point source populations in the Planck catalogue by estimating their spectral indices.Comment: 13 pages, 2 figures, submitted to MNRA

    Pristine Multi-walled carbon nanotubes for a rapid and efficient plasmid DNA clarification

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    Therapeutic approaches based on nucleic acids to modulate cell activity have recently gained attention. These molecules arise from complex biotechnological processes, requiring effective manufacturing strategies, high purity, and precise quality control to be used as biopharmaceuticals. One of the most critical and time-consuming steps for nucleic acids-based biotherapeutics manufacturing is their purification, mainly due to the complexity of the extracts. In this study, a simple, efficient, and reliable method to isolate and clarify plasmid DNA (pDNA) from complex samples is described. The method is based on the selective capture of RNA and other impurities, using pristine carbon nanotubes (CNTs). Multi-walled CNTs (MWCNTs) with different diameters were studied to determine their adsorption capacity and to address their ability to interact and distinguish between nucleic acids. The results revealed that MWCNTs preferentially interact with RNA and that smaller MWCNTs present a higher adsorption capacity, as expected by the higher specific surface area. Overall, this study showed that MWCNTs significantly reduce the levels of impurities, namely RNA, gDNA, and proteins, by approximately 83.6 % compared to their initial level, enabling the recovery of clarified pDNA in solution while maintaining its stability throughout the recovery process. This method facilitates the pre-purification of pDNA for therapeutic applications.publishe
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