Numerical modelling o bed sediment particle tracking in open channel with skewed box-culvert

A particle tracking model was applied to estimate the bed sediment transport in open channel with skewed box-culvert in rivers in Mexico, for which purpose the calculation of the hydrodynamics of the study channel was determined the three-dimensional velocity field [1], later, the calculation of particle transport was obtained, which was determined in any direction of the space caused by the velocity field and the turbulent dispersion (random movement of the Brownian type). The dispersion and re-suspension mechanisms of the particles used were represented by stochastic models, which describe the movement by means of a probability function [2]. The validation of the model was previously carried out by [3], obtaining average relative errors of less than 4.8%. Three numerical scenarios were calculated including different alternatives and its behaviour at the entrance, interior and exit of the water flow in the construction to determine which is the best option to be used on the skewed multi barrel crossings. In order to accomplish this, a variable slope channel and 1: 60 scale models of box culverts with 10, 22 and 45 degrees of skewedness were used. The results observed in the multi-eyed box culverts were favourable, due to the fact that the speed utside of them, which favours the hydrodynamic behaviour and minimize the accumulation of sediment into structure in the river

Modelación numérica hidrodinámico-hidrológica en zonas de inundación con presencia de infraestructura

Se presenta la modelación numérica computacional de la hidrodinámica superficial e hidrológica de la zona de estudio donde se pretende construir infraestructura para la exploración de hidrocarburos en las márgenes del río Grijalva, México; para ello se muestra el análisis de la información meteorológica, determinando los valores de intensidad de precipitación, temperaturas, evaporación y una estimación de los gastos, correspondiente al año 2014; las zonas de inundación se estimaron con el uso de programas desarrollados en Fortran y Matlab, que resuelven las ecuaciones de Navier-Stokes-Reynolds para flujos a superficie libre y la intensidad de precipitación con la distribución de Gumbel, con parámetros estimados mediante el método de Momentos Ponderados con Probabilidad (MPP), con los cuales, mediante una malla numérica de la topografía, en conjunto con los valores meteorológicos, como condiciones iniciales y forzantes, se determina la magnitud de la inundación del área de estudio, así como la obtención de gastos, velocidades y el funcionamiento hidráulico de las obras de mitigación propuestas para preservar el balance hidrológico del sistema

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

Weakly Coupled Distributed Calculation of Lyapunov Exponents for Non-Linear Dynamical Systems

Numerical estimation of Lyapunov exponents in non-linear dynamical systems results in a very high computational cost. This is due to the large-scale computational cost of several Runge–Kutta problems that need to be calculated. In this work we introduce a parallel implementation based on MPI (Message Passing Interface) for the calculation of the Lyapunov exponents for a multidimensional dynamical system, considering a weakly coupled algorithm. Since we work on an academic high-latency cluster interconnected with a gigabit switch, the design has to be oriented to reduce the number of messages required. With the design introduced in this work, the computing time is drastically reduced, and the obtained performance leads to close to optimal speed-up ratios. The implemented parallelisation allows us to carry out many experiments for the calculation of several Lyapunov exponents with a low-cost cluster. The numerical experiments showed a high scalability, which we showed with up to 68 cores

Light Particle Tracking Model for Simulating Bed Sediment Transport Load in River Areas

In this work a fast computational particles tracer model is developed based on Particle-In-Cell method to estimate the sediment transport in the access zone of a river port area. To apply the particles tracer method, first it is necessary to calculate the hydrodynamic fields of the study zone to determine the velocity fields in the three directions. The particle transport is governed mainly by the velocity fields and the turbulent dispersion. The mechanisms of dispersion and resuspension of particles are based in stochastic models, which describes the movement through a probability function. The developed code was validated using two well known cases with a discrete transformation obtaining a max relative error around 4.8% in both cases. The simulations were carried out with 350,000 particles allowing us to determine under certain circumstances different hydrodynamic scenarios where the zones are susceptible to present erosion and siltation at the entrance of the port

100 Cartas para Paulo Freire de quienes pretendemos Enseñar

Realizar un texto colectivo como “100 Cartas para Paule Freire de quienes pretendemos Enseñar”, es un desafío al reunir el aprehender desde el sentido profesional de la educación y con el espíritu de transformación, desde la educación como un espacio endógeno de revolución y exógeno a las comunidades y sociedades, en busca de un sentido de identidad. Hoy desde una crítica decolonial, antirracista, feminista y ecologica en la construcción de un sentido real que busque enfrentar el sistema hegemónico y destructivo que se ha impuesto con explotación, sangre y libertades de nuestro pueblo

Revista Temas Agrarios Volumen 26; Suplemento 1 de 2021

1st International and 2nd National Symposium of Agronomic Sciences: The rebirth of the scientific discussion space for the Colombian Agro.1 Simposio Intenacional y 2 Nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano