Modelo mecánico de los músculos extrínsecos del globo ocular

The mathematical modeling of the physiological behavior of extraocular muscles in ocular rotation, contributes to the learning of the oculomotor system and the development of technologies for the control of devices, through the precise prediction of the ocular displacement path. We propose in this article a mechanical model of eye movement, which incorporates the physiological properties of extraocular muscles in the force-elongation relationship and the action of agonist and antagonist muscles. An easy to understand model is presented that allows the analysis of forces applied in muscle contraction, the variation of extraocular muscle length, which generates rotation of the eye and the vector interpretation of the direction in the space towards which the eye directs the view, in movements of adduction, abduction, elevation and depression. The proposed model allows a simplification of the mathematical description, compared with other models, in relation to the action of the mechanical elements (springs and dampers) that represent the anatomical and physiological components of the contractile mechanics of the extraocular muscles. The implementation of the proposed model could serve in the future in the development of technologies that emulate horizontal or vertical eye movements for the control of devices.El modelamiento matemático del comportamiento fisiológico de los músculos extraoculares en la rotación ocular, contribuye en el aprendizaje del sistema oculomotor y en el desarrollo de tecnologías para el control de dispositivos, a través de la predicción precisa de la trayectoria de desplazamiento ocular. Nosotros proponemos en el presente artículo un modelo mecánico del movimiento ocular, que incorpora las propiedades fisiológicas de los músculos extraoculares en la relación de fuerza-elongación y la acción de los músculos agonistas y antagonistas. Se presenta un modelo de fácil comprensión que permite el análisis de fuerzas aplicadas en la contracción muscular, la variación de longitud del musculo extraocular, que genera rotación del ojo y la interpretación vectorial de la dirección en el espacio hacia donde el ojo dirige la vista en movimientos de aducción, abducción, elevación y depresión. El modelo propuesto permite una simplificación de la descripción matemática, frente a otros modelos, de la acción de los elementos mecánicos (resortes y amortiguadores) que representan los componentes anatómicos y fisiológicos de los músculos extraoculares. La implementación del modelo propuesto podría servir a futuro en el desarrollo de tecnologías que emulen movimientos oculares horizontales u verticales para el control de dispositivos

Reconstrucción 3D de órgano a partir de imágenes de Tomografía Axial Computarizada (TC) usando Matlab

The three-dimensional processing and reconstruction of anatomical regions from medical images allows the application of a set of segmentation and filtering techniques to subsequently perform volumetric reconstructions and thus generate 3D computer representations of human anatomy, which is useful in the field of medicine to facilitate the analysis of human body structures.  In this paper, a 3D reconstruction was performed from the segmentation, based on the differentiation by area, of the organ (kidney) and bone structures from a series of images from an abdominal CT. Also, we implemented an interactive interface for the visualization of the planes (frontal, sagittal and transversal). The interface that shows the different planes and also loads the 3D reconstruction that was generated in a separate process, gives the user the option to select any CT study that he has stored in his computer. This procedure, depending on the field of application, complements the interaction and analysis of anatomical structures to the physician, allowing the planning of a timely treatment that will help the preoperative analysis of complex pathologies and the formulation of surgical strategies.El procesamiento tridimensional y la reconstrucción de las regiones anatómicas a partir de imágenes médicas permiten aplicar un conjunto de técnicas de segmentación y filtrado para para realizar posteriormente reconstrucciones volumétricas y así generar representaciones computacionales en 3D de la anatomía humana, que es útil en el campo de la medicina para facilitar análisis de las estructuras del cuerpo humano.  En este artículo, se realizó una reconstrucción 3D a partir de la segmentación, basada en la diferenciación por área, del órgano(riñón) y estructuras óseas de una serie de imágenes de un TAC abdominal. También, implementamos una interfaz interactiva para la visualización de los planos (frontal, sagital y transversal). La interfaz que muestra los diferentes planos y también carga la reconstrucción 3D que se generó en un proceso aparte, da la opción al usuario de seleccionar cualquier estudio TAC que tenga almacenado en su ordenador. Este procedimiento, según el campo de aplicación, complementa la interacción y análisis de estructuras anatómicas al médico, permite planificar un tratamiento oportuno que ayudará al análisis preoperatorio de patologías complejas y la formulación de estrategias quirúrgicas

Modelamiento de la arteria carótida

This study presents a modelling for the carotid artery that allows to analyze the theoretical behavior of pressure, flow and arterial volume in it, from the variation of both physical and physiological characteristics, such as: the thickness and length of the vessel blood, the viscosity and density of blood; determinants in the study of the normal functionality of the artery. The model of the arterial vessel –an adaptation of the Windkessel model of three elements, reported by Westerhof and Stergiopulos–, consists of an electrical circuit composed of passive RLC elements. The arterial segment was analyzed by mathematical and computational tools, relating Poiseuille's laws and electric laws. The pressure, flow and volume curves were obtained when changes occurred in the measurable characteristics of the carotid artery, in order to facilitate the medical interpretation of possible pathologies related to these changes.Este estudio presenta un modelado para la arteria carótida que permite analizar el comportamiento teórico de la presión, el flujo y el volumen arterial en ella, a partir de la variación de características tanto físicas como fisiológicas tales como: el espesor y longitud del vaso sanguíneo, la viscosidad y densidad de la sangre; determinantes en el estudio de la funcionalidad normal de tal arteria. El modelo del vaso arterial, –una adaptación del modelo de Windkessel de tres elementos reportado por Westerhof y Stergiopulos–, consiste en un circuito eléctrico compuesto de elementos pasivos RLC. El segmento arterial se analizó mediante herramientas matemáticas y computacionales, relacionando las leyes de Poiseuille y las leyes eléctricas. Se obtuvieron las curvas de presión, flujo y volumen, cuando ocurrían cambios en las características medibles de la arteria carótida, con el fin de facilitar la interpretación médica de posibles patologías relacionadas con estos cambios

Simulador de electromiografía de superficie

The study of electromyographic signals at the time of a global pandemic has been reduced, since the possibility of attending a bio signal laboratory has been null for some people, in this article a surface electromyography simulator (EMGs) is proposed with pedagogical application, this is carried out to characterize a real EMG signal, obtaining characteristics characteristic of it, in the domains of time, such as amplitude and frequency, as the harmonics are signal, noise and randomness, so that in this way, its behavior can be emulated through 21 harmonics (11 for the state of contraction and 10 for the relaxation), using different circuits composed in principle by operational amplifiers, an sEMG signal with behavior similar to a real one is obtained that can be used in signal processing or observing behavior without attending a laboratory.El estudio de señales electromiográficas en tiempo de una pandemia mundial ha sido reducido, puesto que la posibilidad de asistir a un laboratorio de bioseñal ha sido nula para algunas personas, en el presente artículo se propone un simulador de electromiografía de superficie (sEMG) con aplicación pedagógica. Para esto se caracterizó una señal de sEMG real, obteniendo características de amplitud y frecuencia para los eventos relajación y contracción voluntaria de un musculo. Las señales características de relajación y contracción se simularon mediante señales periódicas, así como los ruidos más frecuentes que contaminan la señal (artefactos por movimiento, 60Hz de la línea eléctrica y transmisiones de radio). Las señales constan de 21 armónicos (11 para el estado de contracción y 10 para el de relajación), sumadas y acondicionada con amplificadores operacionales. Las señales de sEMG obtenidas, presentan características similares a las señales reales. Esta simulación de EMG puede ser utilizada en el desarrollo de dispositivos que necesiten de la captura de señales EMG

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

Métodos y técnicas de monitoreo y predicción temprana en los escenarios de riesgos socionaturales

Esta obra concentra los métodos y las técnicas fundamentales para el seguimiento y monitoreo de las dinámicas de los escenarios de riesgos socionaturales (geológicos e hidrometeorológicos) y tiene como objetivo general orientar, apoyar y acompañar a los directivos y operativos de protección civil en aterrizar las acciones y políticas públicas enfocadas a la gestión del riesgo local de desastre

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Measurement of the azimuthal anisotropy of Y(1S) and Y(2S) mesons in PbPb collisions at root s(NN)=5.02 TeV

The second-order Fourier coefficients (v(2)) characterizing the azimuthal distributions of Y(1S) and Y(2S) mesons produced in PbPb collisions at root s(NN) = 5.02 TeV are studied. The Y mesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The collected data set corresponds to an integrated luminosity of 1.7 nb(-1). The scalar product method is used to extract the v2 coefficients of the azimuthal distributions. Results are reported for the rapidity range vertical bar y vertical bar < 2.4, in the transverse momentum interval 0 < pT < 50 GeV/c, and in three centrality ranges of 10-30%, 30-50% and 50-90%. In contrast to the J/psi mesons, the measured v(2) values for the Y mesons are found to be consistent with zero. (C) 2021 The Author(s). Published by Elsevier B.V.Peer reviewe