A result on the existence and uniqueness of stationary solutions for a bioconvective flow model

In this note we prove the existence and uniqueness of weak solutions for the boundary value problem modelling the stationary case of the bioconvective flow problem introduced by Tuval et. al. (2005, {\it PNAS} 102, 2277--2282). We derive some appropriate a priori estimates for the weak solution, which implies the existence, by application of Gossez theorem, and the uniqueness by standard methodology of comparison of two arbitrary solutions.Comment: 6 pages, 0 figure

Ruiz Moreno, Isidoro. Comandos en acción. Buenos Aires: Editorial Claridad, 2012, 352 p. ISBN: 978-950-620-312-2.

Fil: Tello, José Luis. Universidad Nacional de Cuy

Enrique Díaz Araujo, Ernesto Guevara de la Serna, aristócrata, aventurero y comunista. Mendoza: Ediciones del Verbo Encarnado, 2008, 424 p. ISBN: 978987-9438-14-5.

Fil: Tello, José Luis. Universidad Nacional de Cuy

Influencia del factor de reducción de resistencia sísmica (R) en edificaciones, utilizando los sistemas constructivos: Dual losas postensadas-muros y tradicional

Se presenta un análisis de catorce modelos estructurales de los cuales siete corresponden a edificaciones de hormigón armado y siete a edificaciones con sistema dual de losas postensadas y muros de corte, modelados y analizados a partir de las herramientas computacionales ETABS-2016 y SAFE12. Se sometió a las estructuras a un análisis estático lineal considerando el cumplimiento de los controles establecidos en la norma NEC-SE-DS, 2015 garantizando un adecuado comportamiento sismo-resistente en las mismas. Además, se realizó un análisis no lineal, obteniendo la curva de capacidad de las estructuras, con el fin de determinar parámetros que permitan calcular el Factor de Reducción de Resistencia Sísmica (R) en cada modelo. Los resultados del factor R fueron obtenidos a partir de varios métodos vigentes y comparados con lo tabulado en norma, llegando a determinar que la media de los valores para el caso del sistema de pórticos de hormigón armado es 6.01, mientras que, para el caso del sistema dual de losas postensadas y muros de corte es 6.66, es decir 24.86% y 16.77% menor a lo considerado en norma, correspondientemente.An analysis of fourteen structural models is presented, seven of which correspond to reinforced concrete buildings and seven to buildings with dual system of post-tensioned slabs and cutting walls, modeled and analyzed from the tools ETABS-2016 and SAFE12. The structures were subjected to a linear static analysis considering compliance with the controls set out in the NEC-SE-DS standard, 2015 ensuring adequate seismic-resistant behavior in them. In addition, a nonlinear analysis was performed, obtaining the capacity curve of the structures, in order to determine parameters that allow to calculate the Seismic Resistance Reduction Factor (R) in each model. The results of the R-factor were obtained from several methods in force and compared to the norm, going so far as to determine that the mean of the values for the case of the reinforced concrete porch system is 6.01, while, for that case of the dual system of post-tensioned slabs and cutting walls is 6.66, that is 24.86% and 16.77% lower than considered in the norm, correspondingly

Evaluación comparativa del rendimiento de controladores SDN de código abierto

Software-defined Networking (SDN) constitutes a new era in the development of internetworking. The SDN paradigm splits the data plane from the control plane. It uses controller equipment, which is responsible for centrally managing several network devices simultaneously. This study analyzes three open-source controllers for SDN based on the OpenFlow protocol. Specifically, the performance of FloodLight, OpenDayLight (ODL), and Ryu controllers is evaluated in terms of latency, throughput, and scalability. In doing so, the Cbench tool is used in an emulated environment with Mininet. The results show that the Ryu controller presents the lowest performance in all the evaluated parameters; ODL provides lower latency and FloodLight higher throughput. Regarding scalability, we conclude that Floodlight can be used in small networks, whereas ODL can be used in dense networks. Furthermore, we evaluate their main characteristics, which must be considered for their choice prior to implementation and deployment.Las redes definidas por software (SDN) constituyen una nueva era en el diseño de la interconexión de redes. El paradigma SDN separa el plano de datos del plano de control. Para esto utiliza un equipo controlador, que se encarga de gestionar de forma centralizada varios dispositivos de red al mismo tiempo. Este estudio analiza tres controladores SDN de código abierto basados en el protocol OpenFlow. Específicamente, el rendimiento de los controladores FloodLight, OpenDayLight (ODL) y Ryu son evaluados en términos de latencia, throughput y escalabilidad. Para ello se utilizó la herramienta Cbench en un entorno emulado con Mininet. Los resultados muestran que el controlador presenta un menor rendimiento en todos los parámetros evaluados; ODL tiene una menor latencia y Floodlight un mayor throughput. En lo que tiene que ver a escalabilidad, se concluye que Floodlight es recomendable para redes pequeñas y ODL para redes densas. Además, evaluamos sus principales características, las cuales deben ser tomadas en cuenta para su elección antes de su implementación y despliegue

Lugones in Mendoza : the reception of his work and ideas in the newspaper Los Andes, 1897-1930

El artículo trata la recepción de Leopoldo Lugones en la prensa de Mendoza (Argentina) especialmente a través de su principal diario, Los Andes, entre 1897-1930. La indagación permitió comprobar, hasta principios de la década de 1920, la difusión de numerosas publicaciones del autor, así como noticias de sus conferencias y de su actuación como funcionario del Estado nacional. Si bien el diario reprodujo solo tres textos del escritor argentino, su exitosa estadía en la provincia, durante 1923, para dar una serie de conferencias, muestra que era conocido y leído, aunque necesariamente en un público selecto. Las charlas que desarrolló en Mendoza tocaron algunos de los temas que siempre le interesaron, como fueron la educación, la ciencia y el mundo clásico. Luego de esta visita, la información sobre el poeta decayó y sólo aparecieron algunas crónicas y comentarios de sus libros y conferencias. Incluso la principal biblioteca pública de la provincia, “General San Martín", cuenta con un escaso número de obras, la última de las cuales está fechada en el año 1926, lo que confirma el poco interés oficial por su producción intelectual.The article treats the reception of Leopoldo Lugones in the press of Mendoza (Argentina) especially through its main newspaper, Los Andes, between 1897-1930. The investigation allowed the publication of numerous publications of the author, as well as news of his lectures and his performance as an official of the national State, until the early 1920s. Although the newspaper reproduced only three texts by the Argentine writer, his successful stay in the province during 1923, to give a series of lectures, shows that he was known and read, although necessarily in a select audience. The talks he developed in Mendoza touched on some of the topics that always interested him, such as education, science and the classical world. After this visit, information about the poet declined and only appeared some chronicles and comments of his books and lectures. Even the main public library in the province, "General San Martin", has a limited number of works, the last of which is dated in 1926, confirming little official interest in his intellectual production.Fil: Barrio de Villanueva, Patricia. Consejo Nacional de Investigaciones Científicas y TécnicasFil: Tello, José Luis. Universidad Nacional de Cuyo. Facultad de Filosofía y Letra

Tiempo puerta-aguja y morbimortalidad de pacientes con infarto agudo de miocardio con elevación del segmento ST

Antecedentes: El infarto agudo de miocardio es la principal de causa de muerte de origen cardiovascular en el mundo, siendo de suma importancia su pronto diagnóstico y tratamiento, debido a su influencia en el pronóstico de los pacientes. Objetivos: El presente trabajo desea establecer cuál es la correlación que existe entre el tiempo puerta-aguja y la morbimortalidad en los pacientes con infarto agudo de miocardio con elevación del segmento ST. Material y métodos: se revisaron historias clínicas de los pacientes admitidos en el Hospital Belén de Trujillo con infarto agudo de miocardio con elevación del segmento ST (IMASTE) en un intervalo de 7 años, enfatizando en el tiempo puerta-aguja, así como la arritmia post-infarto, alteraciones de la FEVI y/o muerte. Resultados: La edad media fue 64,48 ± 11,02 años, el total de pacientes de sexo masculino fue de 36 (72%), el tiempo puerta-aguja promedio fue de 148,74 ± 102,77 minutos, con una incidencia de arritmia post-infarto del 52%, alteraciones de FEVI del 66% y una mortalidad de 22%. El análisis correlacional entre las variables estudiadas brinda una intensidad moderada para el tiempo puerta-aguja, la presencia de arritmia, alteraciones de FEVI y mortalidad. Conclusiones: Existe una correlación de intensidad moderada entre el tiempo puerta-aguja y la morbimortalidad en los pacientes con IMASTE.Background: Acute myocardial infarction is the main cause of death in the world, so it’s very important an early diagnosis and treatment, because of its influence in the prognosis of these patients. Objectives: This article wants to establish the correlation between the door-to-needle time and the morbimortality in patients with ST-segment elevation myocardial infarction. Methods: data was collected from the medical record of the patients admitted to the Hospital Belen de Trujillo with a diagnosis of ST-segment elevation myocardial infarction (STEMI) over a period of 5 years and 6 months, emphasizing in the delay of the fibrinolytic therapy since the arrival to the Emergency Department, and also in post-infarction arrhythmias, LVEF imapirment and/or death. Results: the mean age was 64,48 ± 11,02 years, male patients were 36 (72%), the mean door-to-needle time was 148,74 ± 102,77 minutes. The incidencia of post-infarction arrhythmias was 52%, impairment of left ventricle ejection fraction was 66% and mortality was 22%. The correlational analysis of the study variables showed a moderate intensity between the door-to-needle time, presence of arrhythmias, LVEF impairment and mortality Conclussions: our study showed a moderate intensity correlation between the door-to-needle time and morbimortailty in patients with STEMI.Tesi

Field Fluctuations and Casimir Energy of 1D-Fermions

Producción CientíficaWe investigate the self-adjoint extensions of the Dirac operator of a massive one-dimensional field of mass m confined in a finite filament of length L. We compute the spectrum of vacuum fluctuations of the Dirac field under the most general dispersionless boundary conditions. We identify its edge states in the mass gap within a set of values of the boundary parameters, and compute the Casimir energy of the discrete normal modes. Two limit cases are considered, namely, that of light fermions with mL 1, and that of heavy fermions for which mL 1. It is found that both positive and negative energies are obtained for different sets of values of the boundary parameters. As a consequence of our calculation we demonstrate that the sign of the quantum vacuum energy is not fixed for exchange-symmetric plates (parity-invariant configurations), unlike for electromagnetic and scalar fields.Ministerio de Economía, Industria y Competitividad (grant MTM2014-57129-C2-1-P)Junta de Castilla y León - Fondo Europeo de Desarrollo Regional (grants VA057U16 and BU229P18)Junta de Castilla y León (grant VA137G18

Performance Study and Enhancement of Access Barring for Massive Machine-Type Communications

[EN] Machine-type communications (MTC) is an emerging technology that boosts the development of the Internet of Things by providing ubiquitous connectivity and services. Cellular networks are an excellent choice for providing such hyper-connectivity thanks to their widely deployed infrastructure, among other features. However, dealing with a large number of connection requests is a primary challenge in the cellular-based MTC. Severe congestion episodes can occur when a large number of devices try to access the network almost simultaneously. Extended access barring (EAB) is a congestion control mechanism for the MTC that has been proposed by the 3GPP. In this paper, we carry out a thorough performance analysis of the EAB and show the limitations of its current specification. To overcome these limitations, we propose the two enhanced EAB schemes: the combined use of the EAB and access class barring, and the introduction of a congestion avoidance backoff after the barring status of a UE is switched to unbarred. It is shown through extensive simulations that our proposed solutions improve the key performance indicators. A high successful access probability can be achieved even in heavily congested scenarios, the access delay is shortened, and, most importantly, the number of required preamble retransmissions is reduced, which results in significant energy savings. Furthermore, we present an accurate congestion estimation method that solely relies on the information available at the base station. We show that this method permits a realistic and effective implementation of the EAB.This work was supported in part by the Ministerio de Ciencia, Innovacion y Universidades (MCIU), Agencia Estatal de Investigacion (AEI) y Fondo Europeo de Desarrollo Regional (FEDER), UE, under Grant PGC2018-094151-B-I00, and in part by the ITACA Institute under Grant Ayudas ITACA 2019Vidal Catalá, JR.; Tello-Oquendo, L.; Pla, V.; Guijarro, L. (2019). Performance Study and Enhancement of Access Barring for Massive Machine-Type Communications. IEEE Access. 7:63745-63759. https://doi.org/10.1109/ACCESS.2019.2917618S6374563759