Deep Neural Networks for ECG-Based Pulse Detection during Out-of-Hospital Cardiac Arrest

The automatic detection of pulse during out-of-hospital cardiac arrest (OHCA) is necessary for the early recognition of the arrest and the detection of return of spontaneous circulation (end of the arrest). The only signal available in every single defibrillator and valid for the detection of pulse is the electrocardiogram (ECG). In this study we propose two deep neural network (DNN) architectures to detect pulse using short ECG segments (5 s), i.e., to classify the rhythm into pulseless electrical activity (PEA) or pulse-generating rhythm (PR). A total of 3914 5-s ECG segments, 2372 PR and 1542 PEA, were extracted from 279 OHCA episodes. Data were partitioned patient-wise into training (80%) and test (20%) sets. The first DNN architecture was a fully convolutional neural network, and the second architecture added a recurrent layer to learn temporal dependencies. Both DNN architectures were tuned using Bayesian optimization, and the results for the test set were compared to state-of-the art PR/PEA discrimination algorithms based on machine learning and hand crafted features. The PR/PEA classifiers were evaluated in terms of sensitivity (Se) for PR, specificity (Sp) for PEA, and the balanced accuracy (BAC), the average of Se and Sp. The Se/Sp/BAC of the DNN architectures were 94.1%/92.9%/93.5% for the first one, and 95.5%/91.6%/93.5% for the second one. Both architectures improved the performance of state of the art methods by more than 1.5 points in BAC.This work was supported by: The Spanish Ministerio de Economía y Competitividad, TEC2015-64678-R, jointly with the Fondo Europeo de Desarrollo Regional (FEDER), UPV/EHU via GIU17/031 and the Basque Government through the grant PRE_2018_2_0260

Noninvasive Monitoring of Manual Ventilation during Out-of- Hospital Cardiopulmonary Resuscitation

Cardiopulmonary resuscitation (CPR) consisting of chest compressions and assisted ventilation is crucial to treat out-of-hospital cardiac arrest (OHCA). It is well reported that quality of manual ventilations, in terms of rate and volume, is suboptimal, with a high incidence of hyperventilation, which is linked to poor outcomes. The lack of a noninvasive technology to monitor ventilations during out-of-hospital CPR precludes feedback on ventilations to the rescuer, and it handicaps the evaluation of the effect of ventilations on the outcome of the patient. This chapter addresses the possibilities and challenges of monitoring the quality of manual ventilations in current defibrillators. Methods are proposed to monitor ventilations based on the thoracic impedance and the capnogram. These methods can be integrated in defibrillators used in both basic and advanced life support. The algorithms are described, and the accuracy of the methods to monitor the ventilation rate and the quality metrics of the ventilations is reported using real OHCA episodes. The accuracy and limitations of the methods as well as the implications of integrating them in the treatment of patients in cardiac arrest are discussed

Weierstrass Semigroup, Pure Gaps and Codes on Kummer Extensions

We determine the Weierstrass semigroup at one and two totally ramified places in a Kummer extension defined by the affine equation $y^{m}=\prod_{i=1}^{r} (x-\alpha_i)^{\lambda_i}$ over $K$, the algebraic closure of $\mathbb{F}_q$, where $\alpha_1, \dots, \alpha_r\in K$ are pairwise distinct elements, and $\gcd(m, \sum_{i=1}^{r}\lambda_i)=1$. For an arbitrary function field, from the knowledge of the minimal generating set of the Weierstrass semigroup at two rational places, the set of pure gaps is characterized. We apply these results to construct algebraic geometry codes over certain function fields with many rational places.Comment: 24 page

Complete set of Pure Gaps in Function Fields

In this work, we provide a way to completely determine the set of pure gaps $G_0(P_1, P_2)$ at two rational places $P_1, P_2$ in a function field $F$ over a finite field $\mathbb{F}_q$, and its cardinality. Furthermore, we given a bound for the cardinality of the set $G_0(P_1, P_2)$ which is better, in some cases, than the generic bound given by Homma and Kim. As a consequence, we completely determine the set of pure gaps and its cardinality for two families of function fields: the $GK$ function field and Kummer extensions.Comment: 22 page

The Set of Pure Gaps at Several Rational Places in Function Fields

In this work, using maximal elements in generalized Weierstrass semigroups and its relationship with pure gaps, we extend the results in \cite{CMT2024} and provide a way to completely determine the set of pure gaps at several rational places in an arbitrary function field $F$ over a finite field and its cardinality. As an example, we determine the cardinality and a simple explicit description of the set of pure gaps at several rational places distinct to the infinity place on Kummer extensions, which is a different characterization from that presented by Hu and Yang in \cite{HY2018}. Furthermore, we present some applications in coding theory and AG codes with good parameters

Dynamics of a contact line at the nanoscale

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2019, Tutora: Aurora Hernández MachadoIn this TFG we analyze two features of the contact line: the fluctuations around a stationary position and the Contact Angle Hysteresis(CAH). We give an expression for the power spectrum of the fluctuations, and we discuss a model for the CAH. These phenomena have been addressed experimentally, which we will use to show the validity of our mode

Problema extendido de tres cuerpos, restringido y circular

Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2020, Director: Antoni Benseny[en] The Extended Circular Restricted Three-Body Problem studies the motion of three bodies which are only exposed to their mutual interaction force $F \sim r^{\alpha}$ . In this problem, the mass of one of the 3 bodies is much smaller than the others, so this third bodie will not disturb the motion of the others. To study the motion of the third body, first we will study the others’ motion, and then we will add the third body, supposing that these two bodies have a circular motion. This body will have its motion under the field that the other 2 bodies generate, so we will study this field. In particular, we will obtain the equilibrium points of the field, and we will discuss analytically their existence. Furthermore, we will obtain the regions of the plane in which the motion will be possible, providing a qualitative description of their boundary. Finally, some of these regions will be simulated, thanks to a program which creation is away of this project

Arquitecturas de aprendizaje profundo para la detección de pulso en la parada cardiaca extrahospitalaria utilizando el ECG

La detección de la presencia de pulso durante la parada cardiorrespiratoria extrahospitalaria es crucial para la supervivencia del paciente. Se ha demostrado que la toma manual del pulso no es muy fiable y que consume demasiado tiempo, por lo que es necesario desarrollar métodos automáticos que ayuden en la identificación del retorno de la circulación espontánea del paciente en parada. En este trabajo se propone utilizar técnicas de aprendizaje profundo para la discriminación automática de ritmos con pulso (PR) y sin pulso (PEA) utilizando solamente información proveniente del ECG. Se ha utilizado una base de datos que contiene 3914 segmentos de 5 segundos (3372 PR y 1542 PEA), que se dividieron en dos bases de datos con pacientes disjuntos para la optimización y evaluación de los métodos. Los mejores resultados se han obtenido utilizando una red neuronal profunda que contiene dos etapas de convolución y una etapa recurrente para la extracción de características y a continuación un clasificador. El modelo se evalúa en términos de sensibilidad (SE, porcentaje de PRs correctamente detectados) y especificidad (SP, proporción de PEAs correctamente detectados). Sobre la base de evaluación se obtuvieron una SE/SP de 94.2%/91.0%, por lo que puede concluirse que la detección automática del pulso utilizando sólo el ECG es viable mediante técnicas de aprendizaje profundo.Este trabajo ha recibido apoyo económico conjunto del Ministerio de Economía y Competitividad Español y del Fondo Europeo de Desarrollo Regional (FEDER) a través del proyecto (TEC2015-64678-R), de la Universidad del País Vasco/Euskal Herriko Unibertsitatea mediante la ayuda a grupos de investigación GIU17/031, y del Gobierno Vasco a través de la beca PRE_2017_1_0112

Equilibrio de nash perfecto en subjuegos: un análisis contrafactual a partir de escenarios simulados de política monetaria y política fiscal en Colombia

En este documento se discuten los resultados de un ejercicio de simulación a partir de métodos de la economía experimental y modelado con elementos de la teoría de juegos, en el cual se formuló un juego secuencial que permitió encontrar equilibrios de Nash perfectos en subjuegos entre las decisiones de política monetaria y las decisiones de política fiscal, en el marco de los objetivos trazados por las autoridades de política económica en Colombia. Se diseñó una situación controlada en la que se definieron supuestos previamente con el fin de observar las estrategias a seguir por los jugadores, las consecuencias de las decisiones que adoptaron y las que no, dada la manipulación de las variables dentro de la simulación, con el propósito de hacer acordes los resultados con una situación económica real. De esta manera, se constató para cada uno de los escenarios planteados en el ejercicio la existencia de equilibrios perfectos en subjuegos en el sentido de Nash, que permitieron develar que la condición de racionalidad maximizadora de los jugadores es el elemento principal a la hora de la toma de decisiones al interior de grupos sociales. Por último, la observación puso en evidencia que las interacciones entre dos agentes están condicionadas por las estrategias que adopte el agente que opere de líder, y que las decisiones del agente seguidor regularmente se basan en criterios cooperativos y de coordinación; en este sentido, se pudo establecer que el Banco de la República determina la manera en la que el Gobierno, respetando los conductos constitucionales, toma sus decisiones de política con el fin de mantener la estabilidad económica del país