Asignación de tareas en sistemas distribuidos de tiempo real

El crecimiento excesivo de la tecnología en las computadoras y el surgimiento de bases de datos con grandes volúmenes de información, han hecho que en los últimos años, el uso de sistemas distribuidos de tiempo real sea tenido en cuenta para el desarrollo de aplicaciones en diversas áreas tales como: sistemas de aviación, orientación de misiles, navegación, sistemas robóticos para manipulación de materiales peligrosos, entre otros. El objetivo de tales sistemas es principalmente proporcionar mejores tiempos de respuesta. Por esta razón, en el contexto de los sistemas distribuidos, despierta interés el problema de asignación de tareas; que es un problema NP-completo. En este artículo se presenta una línea de investigación que consiste en el estudio de algorítmos eficientes para la asignación de tareas.Eje: Procesamiento distribuido y paraleloRed de Universidades con Carreras en Informática (RedUNCI

Inventario de Daños y Efectos Geológicos Co y/o Post-Sísmicos del Sismo Ocurrido el 18 de mayo de 1875, en la Frontera entre Colombia y Venezuela

On the border between Colombia and Venezuela, have occurred seismic events with important records of damage in both countries. In this paper, we study the historical earthquake that took place on May 18, 1875 between 11.15 and 11.30 in the morning (the time was the same for communities in both countries since there was no time zone difference), which is catalogued as a border earthquake due to the report of damages in the cities of both nations. The community of San José de Cúcuta, current capital of the Northern State of Santander, Colombia, registered the greatest number of deaths and damage to buildings. An inventory of the geological damage and co -seismic and postseismic effects was created based on information of previous studies and data obtained from archival primary sources from Colombia and Venezuela. The result is a bi-national database, which includes the summaries of historical descriptions with the effects in the persons and objects, the geological damages and effects observed during the seismic event. These data has led to the creation of a table of MM and EMS-98 intensities, which enables the identification and delimitation of the regions of greater damages. The maximum level intensity is I=10 in the cities of San José de Cúcuta, Villa del Rosario, Pueblo de Cúcuta (San Luis) in Colombia and San Antonio, San Juan de Ureña in Venezuela. Moreover, we formulated a table of intensities using the ESI-2007 INQUA scale, based on the information of geological observations described in historical documents. These data are related to the epicentral zone with an approximate radius of 30 km.Published105-2635T. Sismologia, geofisica e geologia per l'ingegneria sismicaN/A or not JC

Field theories with anisotropic scaling in 2D, solitons and the microscopic entropy of asymptotically Lifshitz black holes

Field theories with anisotropic scaling in 1+1 dimensions are considered. It is shown that the isomorphism between Lifshitz algebras with dynamical exponents z and 1/z naturally leads to a duality between low and high temperature regimes. Assuming the existence of gap in the spectrum, this duality allows to obtain a precise formula for the asymptotic growth of the number of states with a fixed energy which depends on z and the energy of the ground state, and reduces to the Cardy formula for z=1. The holographic realization of the duality can be naturally inferred from the fact that Euclidean Lifshitz spaces in three dimensions with dynamical exponents and characteristic lengths given by z, l, and 1/z, l/z, respectively, are diffeomorphic. The semiclassical entropy of black holes with Lifshitz asymptotics can then be recovered from the generalization of Cardy formula, where the ground state corresponds to a soliton. An explicit example is provided by the existence of a purely gravitational soliton solution for BHT massive gravity, which precisely has the required energy that reproduces the entropy of the analytic asymptotically Lifshitz black hole with z=3. Remarkably, neither the asymptotic symmetries nor central charges were explicitly used in order to obtain these results.Comment: 17 pages, no figures, references corrected and update

ENE-COVID nationwide serosurvey served to characterize asymptomatic infections and to develop a symptom-based risk score to predict COVID-19

Objectives: To characterize asymptomatic SARS-CoV-2 infections and develop a symptom-based risk score useful in primary healthcare. Study design and setting: Sixty-one thousand ninty-two community-dwelling participants in a nationwide population-based serosurvey completed a questionnaire on COVID-19 symptoms and received an immunoassay for SARS-CoV-2 IgG antibodies between April 27 and June 22, 2020. Standardized prevalence ratios for asymptomatic infection were estimated across participant characteristics. We constructed a symptom-based risk score and evaluated its ability to predict SARS-CoV-2 infection. Results: Of all, 28.7% of infections were asymptomatic (95% CI 26.1-31.4%). Standardized asymptomatic prevalence ratios were 1.19 (1.02-1.40) for men vs. women, 1.82 (1.33-2.50) and 1.45 (0.96-2.18) for individuals <20 and ≥80 years vs. those aged 40-59, 1.27 (1.03-1.55) for smokers vs. nonsmokers, and 1.91 (1.59-2.29) for individuals without vs. with case contact. In symptomatic population, a symptom-based score (weights: severe tiredness = 1; absence of sore throat = 1; fever = 2; anosmia/ageusia = 5) reached standardized seroprevalence ratio of 8.71 (7.37-10.3), discrimination index of 0.79 (0.77-0.81), and sensitivity and specificity of 71.4% (68.1-74.4%) and 74.2% (73.1-75.2%) for a score ≥3. Conclusion: The presence of anosmia/ageusia, fever with severe tiredness, or fever without sore throat should serve to suspect COVID-19 in areas with active viral circulation. The proportion of asymptomatics in children and adolescents challenges infection control.The ENE-COVID study was supported by the Spanish Ministry of Health, the Institute of Health Carlos III, and the Spanish National Health System. The funders were in- volved in the study logistics, but they had no role in study design or in the collection, analysis, interpretation of data, or the decision to submit the article for publicationS

Effect Estimates in Randomized Trials and Observational Studies:Comparing Apples With Apples

Effect estimates from randomized trials and observational studies might not be directly comparable because of differences in study design, other than randomization, and in data analysis. We propose a 3-step procedure to facilitate meaningful comparisons of effect estimates from randomized trials and observational studies: 1) harmonization of the study protocols (eligibility criteria, treatment strategies, outcome, start and end of follow-up, causal contrast) so that the studies target the same causal effect, 2) harmonization of the data analysis to estimate the causal effect, and 3) sensitivity analyses to investigate the impact of discrepancies that could not be accounted for in the harmonization process. To illustrate our approach, we compared estimates of the effect of immediate with deferred initiation of antiretroviral therapy in individuals positive for the human immunodeficiency virus from the Strategic Timing of Antiretroviral Therapy (START) randomized trial and the observational HIV-CAUSAL Collaboration

Use of water-Cherenkov detectors to detect Gamma-Ray-Bursts at the Large Aperture GRB Observatory (LAGO)

The Large Aperture GRB Observatory (LAGO) project aims at the detection of high energy photons from Gamma Ray Bursts (GRB) using the single particle technique in ground-based water-Cherenkov detectors (WCD). To reach a reasonable sensitivity, high altitude mountain sites have been selected in Mexico (Sierra Negra, 4550 m a.s.l.), Bolivia (Chacaltaya, 5300 m a.s.l.) and Venezuela (Me´ rida, 4765 m a.s.l.). We report on detector calibration and operation at high altitude, search for bursts in 4 months of preliminary data, as well as search for signal at ground level when satellites report a burst.Fil: Allard, D.. Université Paris Diderot - Paris 7; FranciaFil: Allekotte, Ingomar. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Alvarez, C.. Facultad de Ciencias Fısico-Matematicas; MéxicoFil: Asorey, Hernán Gonzalo. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Barros, H.. Universidad Simon Bolivar; VenezuelaFil: Bertou, Xavier Pierre Louis. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Burgoa, O.. Instituto de Investigaciones Fisicas; BoliviaFil: Gomez Berisso, Mariano. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Martinez, O.. Facultad de Ciencias Fısico-Matematicas; MéxicoFil: Miranda Loza, P.. Instituto de Investigaciones Fısicas; BoliviaFil: Murrieta, T.. Facultad de Ciencias Fısico-Matematicas; MéxicoFil: Perez, G.. Facultad de Ciencias Fısico-Matematicas; MéxicoFil: Rivera, H.. Instituto de Investigaciones Fısicas; BoliviaFil: Rovero, Adrian Carlos. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Saavedra, O.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Salazar, H.. Facultad de Ciencias Fısico-Matematicas ; MéxicoFil: Tello, J. C.. Universidad Simon Bolıvar; VenezuelaFil: Ticona Peralda, R.. Instituto de Investigaciones Fısicas; BoliviaFil: Velarde, A.. Instituto de Investigaciones Fısicas; BoliviaFil: Villaseñor, L.. Universidad de Michoacan; MéxicoFil: Areso, Omar Antonio. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Arnaldi, Luis Horacio. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Dasso, Sergio Ricardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Gonzalez, M.. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Gulisano, Adriana Maria. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Martin, R.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Masías Meza, Jimmy Joel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Sidelnik, Iván Pedro. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Alvarez, W.. Universidad de San Carlos; GuatemalaFil: The LAGO Collaboration

A review of spatial causal inference methods for environmental and epidemiological applications

The scientific rigor and computational methods of causal inference have had great impacts on many disciplines, but have only recently begun to take hold in spatial applications. Spatial casual inference poses analytic challenges due to complex correlation structures and interference between the treatment at one location and the outcomes at others. In this paper, we review the current literature on spatial causal inference and identify areas of future work. We first discuss methods that exploit spatial structure to account for unmeasured confounding variables. We then discuss causal analysis in the presence of spatial interference including several common assumptions used to reduce the complexity of the interference patterns under consideration. These methods are extended to the spatiotemporal case where we compare and contrast the potential outcomes framework with Granger causality, and to geostatistical analyses involving spatial random fields of treatments and responses. The methods are introduced in the context of observational environmental and epidemiological studies, and are compared using both a simulation study and analysis of the effect of ambient air pollution on COVID-19 mortality rate. Code to implement many of the methods using the popular Bayesian software OpenBUGS is provided

Reporte de Infraestructura Financiera 2022

La labor de seguimiento a la infraestructura financiera local es un aporte adicional del Banco de la República a la estabilidad financiera del país. Uno de los productos de dicho seguimiento ha sido el Reporte de Sistemas de Pago, que a partir de esta edición cambia de nombre a Reporte de Infraestructura Financiera, con el objetivo de que refleje de manera amplia los temas que aquí se abordan. En esta edición 2022 se incluyen varios cambios, producto de un estudio comparativo realizado frente a reportes de infraestructura financiera elaborados por otros bancos centrales. Dichos cambios buscan hacer más fluida y liviana la lectura del reporte, incluyendo los mensajes principales y las cifras clave para los diferentes grupos de interés a los cuales va dirigido. En el reporte se muestra que la infraestructura financiera mantuvo sus servicios de forma continua, dando muestra general de su buen funcionamiento en el 2021. Adicionalmente, se validó la resiliencia de la Cámara de Riesgo Central de Contraparte (CRCC) y del Sistema de Pagos de Alto Valor (CUD) ante eventos extremos, con base en pruebas de estrés con estándares internacionales (enfocadas en el riesgo de liquidez y de crédito). En cuanto a los pagos al por menor, de acuerdo con información transaccional, el uso en valor de los instrumentos electrónicos aumentó durante 2021 frente al año 2020 (tarjetas crédito y débito, cheque y transferencias). El empleo de las tarjetas débito y crédito en pagos aumentó a niveles similares a los alcanzados en el año prepandemia. Por su parte, las transferencias electrónicas continuaron en crecimiento. Aunque los resultados de la encuesta BR 2022 muestran que el efectivo continúa siendo el instrumento más utilizado por el público para los pagos habituales (comportamiento similar al de otros países), la percepción de su uso disminuyó significativamente al 75 % (87 % en 2019). También para el comercio, el efectivo fue el instrumento preferido por sus clientes. Sin embargo, en esta medición varios canales de comercio como peluquerías, droguerías y restaurantes se sumaron al grupo que tradicionalmente viene recibiendo pagos electrónicos por un valor superior al 10 % de sus ventas (hipermercados y estaciones de servicio). Asimismo, para cerca del 50 % de la población los pagos en efectivo son menores a los que realizaron antes de la pandemia, lo cual es consecuente con el incremento transaccional de los instrumentos de pago electrónicos que se registró en el año 2021. El Banrep continúa monitoreando los desarrollos tecnológicos que han ampliado y modernizado la oferta en el mercado de pagos internacional y local, ya que son temas de interés para la industria que presta servicios de compensación y liquidación de pagos. En este reporte se presenta el caso PIX en Brasil para pagos inmediatos, los proyectos que se llevan a cabo sobre la posible emisión de moneda digital por parte de los bancos centrales (CBDC, por sus siglas en inglés) para pagos transfronterizos, así como una aproximación al ecosistema Fintech en Colombia con énfasis en las empresas que prestan servicios de pagos. Leonardo Villar Gerente Genera

Dynamics of disease characteristics and clinical management of critically ill COVID-19 patients over the time course of the pandemic: an analysis of the prospective, international, multicentre RISC-19-ICU registry.

BACKGROUND It remains elusive how the characteristics, the course of disease, the clinical management and the outcomes of critically ill COVID-19 patients admitted to intensive care units (ICU) worldwide have changed over the course of the pandemic. METHODS Prospective, observational registry constituted by 90 ICUs across 22 countries worldwide including patients with a laboratory-confirmed, critical presentation of COVID-19 requiring advanced organ support. Hierarchical, generalized linear mixed-effect models accounting for hospital and country variability were employed to analyse the continuous evolution of the studied variables over the pandemic. RESULTS Four thousand forty-one patients were included from March 2020 to September 2021. Over this period, the age of the admitted patients (62 [95% CI 60-63] years vs 64 [62-66] years, p < 0.001) and the severity of organ dysfunction at ICU admission decreased (Sequential Organ Failure Assessment 8.2 [7.6-9.0] vs 5.8 [5.3-6.4], p < 0.001) and increased, while more female patients (26 [23-29]% vs 41 [35-48]%, p < 0.001) were admitted. The time span between symptom onset and hospitalization as well as ICU admission became longer later in the pandemic (6.7 [6.2-7.2| days vs 9.7 [8.9-10.5] days, p < 0.001). The PaO2/FiO2 at admission was lower (132 [123-141] mmHg vs 101 [91-113] mmHg, p < 0.001) but showed faster improvements over the initial 5 days of ICU stay in late 2021 compared to early 2020 (34 [20-48] mmHg vs 70 [41-100] mmHg, p = 0.05). The number of patients treated with steroids and tocilizumab increased, while the use of therapeutic anticoagulation presented an inverse U-shaped behaviour over the course of the pandemic. The proportion of patients treated with high-flow oxygen (5 [4-7]% vs 20 [14-29], p < 0.001) and non-invasive mechanical ventilation (14 [11-18]% vs 24 [17-33]%, p < 0.001) throughout the pandemic increased concomitant to a decrease in invasive mechanical ventilation (82 [76-86]% vs 74 [64-82]%, p < 0.001). The ICU mortality (23 [19-26]% vs 17 [12-25]%, p < 0.001) and length of stay (14 [13-16] days vs 11 [10-13] days, p < 0.001) decreased over 19 months of the pandemic. CONCLUSION Characteristics and disease course of critically ill COVID-19 patients have continuously evolved, concomitant to the clinical management, throughout the pandemic leading to a younger, less severely ill ICU population with distinctly different clinical, pulmonary and inflammatory presentations than at the onset of the pandemic