3,862 research outputs found

    Automatic Detection of Laryngeal Pathology on Sustained Vowels Using Short-Term Cepstral Parameters: Analysis of Performance and Theoretical Justification

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    The majority of speech signal analysis procedures for automatic detection of laryngeal pathologies mainly rely on parameters extracted from time domain processing. Moreover, calculation of these parameters often requires prior pitch period estimation; therefore, their validity heavily depends on the robustness of pitch detection. Within this paper, an alternative approach based on cepstral- domain processing is presented which has the advantage of not requiring pitch estimation, thus providing a gain in both simplicity and robustness. While the proposed scheme is similar to solutions based on Mel-frequency cepstral parameters, already present in literature, it has an easier physical interpretation while achieving similar performance standards

    Perturbative evolution of far off-resonance driven two-level systems: Coherent population trapping, localization, and harmonic generation

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    The time evolution of driven two-level systems in the far off-resonance regime is studied analytically. We obtain a general first-order perturbative expression for the time-dependent density operator which is applicable regardless of the coupling strength value. In the strong field regime, our perturbative expansion remains valid even when the far off-resonance condition is not fulfilled. We find that, in the absence of dissipation, driven two-level systems exhibit coherent population trapping in a certain region of parameter space, a property which, in the particular case of a symmetric double-well potential, implies the well-known localization of the system in one of the two wells. Finally, we show how the high-order harmonic generation that this kind of systems display can be obtained as a straightforward application of our formulation.Comment: 14 pages, LaTeX, 2 figures, acknowledgments adde

    Permanent-magnet atom chips for the study of long, thin atom clouds

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    Atom-chip technology can be used to confine atoms tightly using permanently magnetised videotape along with external magnetic fields. The one-dimensional (1D) gas regime can be realised and studied by trapping the atoms in high-aspect-ratio traps in which the radial motion of the system is confined to zero-point oscillation

    Caracterización parcial de una proteinasa coagulante de la leche aislada del alcaucil (Cynara scolymus L., Asteraceae)

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    The presence of proteinases in Cynara scolyrnus L. ( artichoke ) has been investigated by determining the proteolytic and milk clotting activities of crude extracts of different parts of the inflorescence in various stages of development, as well as of leaves and roots. Although all the preparations showed a certain extent of proteolytic activity, only those of adult leaves, pappus, and immature and mature flowers were able to clot milk. The extract of the upper (violet) part of mature flowers exhibited optimum activity at acid pH values (90% of maximum activity at pH 3.5 - 5.0) which was strongly inhibited by pepstatine A, suggesting the presence of aspartic proteinases. This extract had a low thermal stability at temperatures above 45ºC, which could be a useful property in cheese making process, as it could be quickly inactivated by moderate heating.Se ha estudiado la presencia de proteinasas en el alcaucil (Cynara scolymus L.) midiendo la actividad proteolítica y la capacidad coagulante de la leche de preparaciones crudas de diferentes partes de la inflorescencia en distintos estadios de desarrollo, así como en raíces y hojas. Si bien se detecta actividad proteolitica en todas las preparaciones, sólo las de hojas adultas, de papus y de flores inmaduras y maduras son capaces de coagular la leche. El extracto de la parte superior (violeta) de las flores maduras exhibe un perfil de pH que es óptimo en la zona ácida (90% de máxima actividad entre pH 3,5 y 5,0), pero la actividad es fuertemente inhibida por pepstatina A, lo que sugeriría la presencia de una o más proteinasas aspárticas. La estabilidad térmica del extracto es baja a temperaturas superiores a 45ºC, circunstancia que puede resultar de utilidad en la producción de quesos, ya que la enzima puede ser inactivada a temperaturas moderadas

    Tobacco Taxes as the Unsung Hero: Impact of a Tax Increase on Advancing Sustainable Development in Colombia

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    Objective: Tobacco taxes are a well-established cost-effective policy to prevent Noncommunicable Diseases. This paper evaluates the expected effects of a tobacco tax increase on the Sustainable Development Goals in Colombia. Methods: We use microsimulation to build an artificial society that mimics the observed characteristics of Colombia’s population, and from there we simulate the behavioral response to a tax increase of COP$4,750 (an increase that has been discussed by policy makers and legislators) and the subsequent effects in all SDGs. Results: The tobacco tax hike reduces the number of smokers (from 4.51 to 3.45 MM smokers) and smoking intensity, resulting in a drop in the number of cigarettes smoked in Colombia (from 332.3 to 215.5 MM of 20-stick packs). Such reduction is expected to decrease premature mortality, healthcare costs, poverty and people facing catastrophic expenditure on healthcare, to increase health, income and gender equity, and to strengthen domestic resource mobilization even in the presence of illicit cigarettes. Conclusion: Tobacco taxes are an effective intervention for public health and a powerful instrument to advance on the 2030 Sustainable Development Agenda. Relevance: A comprehensive analysis of the impact of tobacco taxes on all areas of Sustainable Development is missing in the empirical literature. Such perspective is needed to break the barriers for further tobacco tax increases by gathering wider societal support, especially from stakeholders and key decision makers from development areas other than health. SDG Nr: SDG3 (health), SDG 1 (no poverty), SDG 4 (education), SDG 5 (gender equality), SDG6 (water), SDG10 (inequality), SDG12 (responsible production and consumption), SDG17 (partnerships)

    FPGA-Based Urinalysis Using Principal Component Analysis

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    Urinalysis is considered to be a common test performed in laboratory in order to diagnose Urinary Tract Infection (UTI). It undergoes three stages, which include macroscopic, dipstick, and microscopic analysis. This paper describes a way of performing urinalysis for UTI detection using the Principal Component Analysis (PCA) implemented using a Field Programmable Gate Array (FPGA). Input to the system is from five ion-selective sensors that measure five different components specifically sodium, nitrite, nitrate, potassium, and pH level of a urine sample. Tests show that the system obtained an accuracy of 94.13% for standard urinalysis showing the accuracy of sensors and measurements used. To be able to detect the presence of UTI in urines, an outlier detection method Principal Component Analysis (PCA), was used. PCA is a tool used in reducing multidimensional data to lesser dimensions while keeping all the information. An accuracy of 83.33% in detecting UTI infection was achieved. The accuracy of FPGA implementation of PCA was compared with MATLAB calculation results and an accuracy of 99.917% was achieved

    Experiments on a videotape atom chip: fragmentation and transport studies

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    This paper reports on experiments with ultra-cold rubidium atoms confined in microscopic magnetic traps created using a piece of periodically-magnetized videotape mounted on an atom chip. The roughness of the confining potential is studied with atomic clouds at temperatures of a few microKelvin and at distances between 30 and 80 microns from the videotape-chip surface. The inhomogeneities in the magnetic field created by the magnetized videotape close to the central region of the chip are characterized in this way. In addition, we demonstrate a novel transport mechanism whereby we convey cold atoms confined in arrays of videotape magnetic micro-traps over distances as large as ~ 1 cm parallel to the chip surface. This conveying mechanism enables us to survey the surface of the chip and observe potential-roughness effects across different regions.Comment: 29 pages, 22 figures

    Far Ultraviolet Spectra of B Stars near the Ecliptic

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    Spectra of B stars in the wavelength range of 911-1100 A have been obtained with the EURD spectrograph onboard the Spanish satellite MINISAT-01 with ~5 A spectral resolution. IUE spectra of the same stars have been used to normalize Kurucz models to the distance, reddening and spectral type of the corresponding star. The comparison of 8 main-sequence stars studied in detail (alpha Vir, epsilon Tau, lambda Tau, tau Tau, alpha Leo, zeta Lib, theta Oph, and sigma Sgr) shows agreement with Kurucz models, but observed fluxes are 10-40% higher than the models in most cases. The difference in flux between observations and models is higher in the wavelength range between Lyman alpha and Lyman beta. We suggest that Kurucz models underestimate the FUV flux of main-sequence B stars between these two Lyman lines. Computation of flux distributions of line-blanketed model atmospheres including non-LTE effects suggests that this flux underestimate could be due to departures from LTE, although other causes cannot be ruled out. We found the common assumption of solar metallicity for young disk stars should be made with care, since small deviations can have a significant impact on FUV model fluxes. Two peculiar stars (rho Leo and epsilon Aqr), and two emission line stars (epsilon Cap and pi Aqr) were also studied. Of these, only epsilon Aqr has a flux in agreement with the models. The rest have strong variability in the IUE range and/or uncertain reddening, which makes the comparison with models difficult.Comment: 25 pages, 6 figures, to be published in The Astrophysical Journa
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