556 research outputs found
Procesamiento de la actividad eléctrica cardíaca basado en modelos biológicos y matemáticos: detección y cuantificación de riesgo cardíaco
No full textGrado obtenido: Doctor de la Universidad de Buenos AiresDisciplina: IngenieríaFil: Cruces, Pablo Daniel. Universidad de Buenos Aires. Facultad de IngenieríaInstituto de Ingeniería Biomédica, Facultad de Ingeniería – UBA. Instituto Argentino de Matemática "Alberto P. Calderón" – CONICE
An Estimation of CPI Biases in Argentina 1985-2005, and its Implications on Real Income Growth and Income Distribution
No full textWe use the shifts in Engel curves estimated from household surveys to estimate CPI biases in Argentina between 1985 and 2005. We find that real earning levels increased during this period between 4.3 and 5.7% faster per year than previously estimated. More surprisingly, relative to conventional wisdom, that income distribution has improved throughout this period.
Metodología de alta sensibilidad para diagnóstico de infartos
No full textCada año más del 30% de las defunciones son consecuencia de enfermedades cardiovasculares, representando la mayor causa de muerte en Argentina. De todas las patologías, la más común resulta ser el síndrome coronario agudo – daño, isquemia, infarto. Los métodos actuales de diagnóstico combinan estudios enzimáticos, efectivos sólo pocas horas luego del surgimiento de síntomas, e índices electrocardiográficos de baja sensibilidad. Las limitaciones presentes reducen la efectividad en la detección rápida impidiendo eventualmente un tratamiento temprano. En nuestra investigación se ha desarrollado un modelo matemático novedoso que cuantifica la velocidad angular del vector eléctrico cardíaco mediante el procesamiento digital del vectorcardiograma en el cuerpo de los cuaterniones. Dicha velocidad está directamente relacionada a los caminos de conducción eléctrica del miocardio y su combinación con las velocidades lineales clásicas ha permitido el hallazgo de índices de muy alta sensibilidad y especificidad para el diagnóstico de infartos. La eficiencia y robustez del método permiten su simple aplicación a registradores Holter capaces de ser adquiridos por hospitales de bajos recursos. Esto generaría posibilidades de costo reducido para detectar tempranamente enfermedades cardíacas. Además, sería útil en el seguimiento de pacientes a largo plazo, mejorando significativamente los métodos preventivos locales.Fil: Cruces, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin
A novel method for cardiac vector velocity measurement: Evaluation in myocardial infarction
No full textBackground and objective: Pathological alterations provoked by myocardial infarction cause slow conduction by increasing axial resistance on coupling between cells. This issue may cause abnormal patterns in the dynamics of the tip of the cardiac vector. Methods: In this work, we have developed a method to compute the angular velocity during ventricular repolarization from Frank XYZ leads, using the concept of quaternion. This parameter jointly with the linear velocity obtained by differentiation and the spatial velocity reported by others during ventricular depolarization, have been combined in order to design a myocardial infarction detector (so-called index of cardiac vector velocity: ICVV) with high values of sensitivity and specificity simultaneously. Results: The predictive power of ICVV has been tested in two groups: patients with less than 7 days after infarction, achieving 98% of sensitivity and 97% of specificity; and patients with more than 45 days after infarction, achieving 92% of sensitivity without loss of specificity. The former group is important for early detection of myocardial infarction and begins treatment in a short period of time on emergency department. The latter involves the evaluation of the cardiac vector velocity after the period of post-infarction electrical remodeling which may be useful in the follow-up of patients. Conclusions: We have concluded that this method extends the concept of cardiac vector velocity and may be useful in the diagnosis of myocardial infarction.Fil: Cruces, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin
Welfare Programs and Labor Supply in Developing Countries. Experimental Evidence from Latin America
No full textThis paper studies the effect of welfare programs on work incentives and the labor supply of adults in developing countries. The document builds on the experimental evaluations of three programs implemented in rural areas: Mexico’s PROGRESA, Nicaragua’s Red de Protección Social (RPS) and Honduras’ Programa de Asignación Familiar (PRAF). The impact of welfare on labor supply has been widely studied in developed countries, where most recent initiatives attempt to mitigate negative effects on work incentives. The programs under study are conditional cash transfers (CCT), which combine monetary benefits with incentives for curbing child labor and fostering the accumulation of human capital. Unlike their counterparts in developed economies, however, they do not account for potential impacts on the labor supply of adults, and there is little systematic evidence on this aspect despite a wealth of empirical studies on their intended outcomes. Comparable results for the three countries indicate mostly negative but small and non-significant effects of the programs on the employment of adults, no reallocation of labor between agricultural and other sectors, and a reduction in hours worked by adults in eligible households in RPS. Moreover, PROGRESA had a positive effect on beneficiaries’ wages. The programs did not imply major disincentives to work, despite substantial transfers, but they had some effects on local labor markets. This mechanism is related to recent findings on the indirect impact of CCTs on ineligible households, and implies that future evaluation studies and designs should account for the equilibrium effects of the interventions.welfare programs, income support, labor supply, adult work incentives, conditional cash transfers, randomized control trials, developing countries.
Biomarkers of pre-existing risk of Torsade de Pointes under Sotalol treatment
No full textIntroduction: Antiarrhythmic drugs therapies are currently going through a turning point. The high risk that exists during the treatments has led to an ongoing search for new non-invasive toxicity risk biomarkers. Methods: We propose the use of spatial biomarkers obtained through the quaternion algebra, evaluating the dynamics of the cardiac electrical vector in a non-invasive way in order to detect abnormal changes in ventricular heterogeneity. In groups of patients with and without history of Torsade de Pointes undergoing a Sotalol challenge, we compute the radius and the linear and angular velocities of QRS complex and T-wave loops. From these signals we extract significant features in order to compute a risk patient classifier. Results: Using machine learning techniques and statistical analysis, the combinations of few indices reach a pair of sensitivity/specificity of 100%/100% when separating patients with arrhythmogenic substrate. Several biomarkers not only measure drug-induced changes significantly but also observe differences in at-risk patients outperforming current standards. Discussion: Alternative biomarkers were able to describe pre-existing risk of patients. Given the high levels of significance and performance, these results could contribute to a better understanding of the torsadogenic substrate and to the safe development of drug therapies.Fil: Cruces, Pablo Daniel. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Torkar, Drago. Institut Jožef Stefan; EsloveniaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentin
Velocity tracking of cardiac vector loops to identify signs of stress-induced ischaemia
No full textCoronary artery disease (CAD) is among the leading causes of death worldwide. Initial studies require an electrocardiogram stress test often followed by cardiac imaging procedures. However, conventional indices still show insufficient diagnostic performance. We propose quaternion methods to evaluate abnormal alterations during ventricular depolarization and repolarization. Assessment was conducted during a Bruce protocol treadmill stress test and after the end of the exercise. We developed an algorithm to automatically determine the beginning and end of exercise and then, computed the angular and linear velocities. Statistical analysis for feature selection and classification between ischaemic and non-ischaemic patients was used. The most significant markers were maximum linear velocity during ventricular depolarization (p < 5E-9) and maximum angular velocity during the second half of the repolarization loop (p < 5E-16). The latter reached sensitivity / specificity pair of 78 / 92 (AUC 0.89). A linear classifier showed a trend of reduction in cardiac vector velocity in at-risk patients after the end of exercise. The sensitivity / specificity pair reached was 86 / 100. Trajectory deviations of depolarization / repolarization loops that result from ischaemia effects, could be responsible for the observed reduction in dynamic changes during exercise. Further studies could provide non-invasive complementary tools to detect CAD risk.Fil: Cruces, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; ArgentinaFil: Llamedo Soria, Mariano. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; ArgentinaFil: Arini, Pedro David. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin
Dynamic features of cardiac vector as alternative markers of drug-induced spatial dispersion
No full textIntroduction The abnormal amplification of ventricular repolarization dispersion (VRD) has long been linked to proarrhythmia risk. Recently, the measure of VRD through electrocardiogram intervals has been strongly questioned. The search for an efficient and non-invasive surrogate marker of drug-induced dispersion effects constitute an urgent research challenge. Methods Herein, drug-induced ventricular dispersion is generated by d-Sotalol supply in an In-vitro rabbit heart model. A cilindrical chamber simulates the thorax and a multi-electrode net is used to obtain spatial electrocardiographic signals. Cardiac vector dynamics is captured by novel velocity cardiomarkers obtained by quaternion methods. Through statistical analysis and machine learning technics, we compute potential dispersion markers that could define proarrhythmic risk. Results The cardiomarkers with the greatest statistical significance, both obtained from the electrical cardiac vector, were: the QTω, which is the difference between first and last maxima of angular velocity and λ21vT, the roundness of linear velocity. When comparing with the performance of the current standards (89%), this pair was able to correctly separate 21 out of 22 experiments achieving a performance of 95%. Moreover, the QTω computes in a much more robust basis the QT interval, the current index for drug regulation. Discussion These velocity markers circumvent the problems of accuratelly finding the fiducial points such as the always tricky T-wave end. Given the high performance they achieved, it is provided a promising outcome for future applications to the detection of anomalous changes of heterogeneity that may be useful for the purposes of torsadogenic toxicity studies.Fil: Cruces, Pablo Daniel. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Torkar, Drago. Institut ’Jožef Stefan’; EsloveniaFil: Arini, Pedro David. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin
Biblioteca Carlos Gaviria Díaz (Da série “Ver o mundo arder”)
No full textTitle: Carlos Gaviria Díaz Library(From the series “Watching the World Burn”)Author: Daniel Mauricio Correa VelásquezPseudonym: Pablo FracassoTechnique: Oil on canvasDimensions: 170 × 120 cmYear: 2025Título: Biblioteca Carlos Gaviria Díaz(De la serie “Ver el mundo arder”)Autor: Daniel Mauricio Correa VelásquezPseudónimo: Pablo FracassoTécnica: Óleo sobre lienzoDimensiones: 170 × 120 cmAño: 2025Título: Biblioteca Carlos Gaviria Díaz(Da série “Ver o mundo arder”)Autor: Daniel Mauricio Correa VelásquezPseudónimo: Pablo FracassoTécnica: Óleo sobre telaDimensões: 170 × 120 cmAno: 202
Fracture network analysis of Yacoraite Formation in the Tres Cruces sub-basin, northwestern Argentina
No full textThe Tres Cruces sub-basin, located in Jujuy province, northwestern Argentina, is characterized by intense N-S folding and faulting. These structures were formed as a result of the Cenozoic shortening that produced the tectonic inversion of the Salta Rift Basin normal faults. Some of the main folds and faults show abrupt trend variations, controlled by NW-SE transverse lineaments. We performed a fracture network analysis over the Maastrichtian-Danian limestones of the Yacoraite Formation, at three folds located in the central sector of the sub-basin. A total of 832 planar fractures were measured in different structural domains. Five main fracture sets were identified, trending NW-SE, NE-SW, ENE-WSW, WNW-ESE and N-S to NNW-SSE. Their relative chronology was established based on the observed abutting relationships. The analysis performed suggests that NW-SE, NE-SW and ENE-WSW trending sets are regionally represented and were formed before the initial stages of folding. Set ENE-WSW is sub-parallel to the convergence direction acting during the Neogene. The other two sets are associated with local perturbations of the far-field signal control by the oblique NW-SE lineaments. The origin of the WNW-ESE set remains unclear; its distribution is locally restricted to the San Bernardo domain. Finally, the N-S to NNW-SSE set shows a synfolding origin generated when the surveyed folds were growing. We then place the various identified fracture sets into a single stress field setting, perturbed by the leading NW-SE transverse lineaments that dominate this region.Fil: Correa Luna, Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Yagupsky, Daniel Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Likerman, Jeremias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin
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