Link between optimization and local stability of a low-dissipation heat engine: Dynamic and energetic behaviors

[EN]In the present paper we study the connection between local stability and energetic properties in low-dissipation heat engines operating in the maximum-power and maximum-compromise ( ) regimes. We consider two different feedback regulatory pathways: (1) one in which restitutive forces linearly depend on the deviations from the stationary values of the heat exchanges with the hot and cold reservoirs and (2) another where restitutive forces depend on the deviations from the stationary values of the power output and the heat outflux into the cold reservoir. The first dynamics leads to an isolated stable point while in the second one the system is metastable. Further analysis of random perturbations from the steady state gives valuable information about the dynamic behavior of thermodynamic properties like entropy, power, and efficiency in both operation regimes

Planeamiento estratégico del Banco Interamericano de Finanzas

La presente tesis desarrolla el planeamiento estratégico para la Banco Interamericano de Finanzas S.A., Banbif, bajo el Modelo Secuencial del Proceso Estratégico elaborado por D’Alessio (2008). El Banbif es una entidad financiera que forma parte del grupo Ignacio Fierro, cuya misión es realizar actividades de intermediación financiera, a través de la captación y colocación de fondos, así como diversos servicios a la banca múltiple. El objetivo del presente planeamiento busca asegurar la sostenibilidad y crecimiento del negocio, a través de la creación de mejores productos y servicios eficientes, innovadores y de alta calidad, orientados principalmente a la mediana empresa y a las personas de nivel socioeconómico A,B y C. Esta propuesta de planeamiento busca orientar las decisiones de los directivos del Banbif para los próximos diez años, teniendo en cuenta la disminución en el ahorro y la inversión que se ha visto en el Perú entre los años 2011 al 2015. La tesis consta de ocho capítulos que incluyen el análisis de la situación actual y entorno, la formulación y diseño de estrategias, la implementación y la evaluación y control; y un capítulo final con las conclusiones y recomendaciones para la compañía Banbif. Finalmente, la presente tesis recomienda la implementación del presente planeamiento teniendo en cuenta la situación del sector financiero y económico del Perú al 2015.This thesis develops the strategic planing for the Banco Interamericano de Finanzas S.A., Banbif, under the strategic process sequence model elaborated by D’Alessio (2008). The Banbif is a finantial institution, that is part of Ignacio Fierro group, whose mission is to carry out financial transactions through the recruitment and placement of funds and various services to multiple bank. The aim of this planning seeks to ensure the sustainability and growth of the business, through the creation of better products and efficient, innovative and high quality services, mainly oriented to medium enterprises and people of high socioeconomic status. This proposal seeks to guide planning decisions by managers BanBif for the next ten years, considering the decline in the savings and investments occurred in Peru between 2011 and 2015. The thesis has eight chapters that include the current situation analysis and environment, the design and formulation of the strategies, implementation and evaluation and control, furthermore, a chapter with recommendations and conclusions for the Banbif. Finally, this thesis recommends the implementation of this planning considering the situation in the financial and the economic sector in Peru at 2015.Tesi

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Local Stability Analysis for a Thermo-Economic Irreversible Heat Engine Model under Different Performance Regimes

A recent work reported a local stability analysis of a thermo-economical model of an irreversible heat engine working under maximum power conditions. That work showed that after small perturbations to the working temperatures, the system decreases exponentially to the steady state characterized by two different relaxation times. This work extends the local stability analysis considering other performance regimes: the Maximum Efficient Power (MEP) and the Ecological Function (EF) regimes. The relaxation time was shown under different performance regimes as functions of the temperature ratio τ = T2/T1, with T1 &gt; T2, the fractional fuel cost f and a lumped parameter R related to the internal irreversibilities degree. Under Maximum Efficient Power conditions the relaxation times are less than the relaxation times under both Maximum Ecological function and Maximum Power. At Maximum Power Efficient conditions, the model gives better stability conditions than for the other two regimes

Archaeology and recent volcanism in the Zacapu lacustrine basin (Michoacán, Mexico). Fieldtrip Guide: 80th anniversary of Paricutin volcano

International audienc

Arqueología y vulcanismo reciente en la cuenca lacustre de Zacapu (Michoacán, México). Guía de Campo: 80 aniversario del Paricutín

International audienc

Utilización de plasma rico en plaquetas como tratamiento coadyuvante en la no unión de olecranon en un perro: Reporte de caso

Las plaquetas son componentes clave en la hemostasia, estimulan la construcción de nuevo tejido conectivo y revascularización. Pueden ser transfundidas a los pacientes con trombocitopenia grave o disfunción plaquetaria y también para evitar hemorragias o inducir hemostasia (Sashwati y col. 2011). El plasma rico en plaquetas (PRP) es un concentrado autólogo de plaquetas en un pequeño volumen, fuente rica de factores de crecimiento. Actualmente representa una biotecnología emergente en la ingeniería de tejidos y la terapia celular (Nguyen 2011). La mayoría de las investigaciones sobre los PRP se ha centrado en sus efectos sobre los tejidos conectivos, como tendones, ligamento y el músculo. Pocos estudios mencionan su empleo para promover la osteogénesis. No se encontraron reportes de la utilización de PRP como tratamiento coadyuvante en reparaciones de fracturas con diagnóstico de no unión en perros (Dohan y col. 2008). La actividad anabólica y la capacidad de inducir la diferenciación de condrocitos y tenocitos son características importantes a considerar en traumatología (Jiang y col. 2012). El presente trabajo propone el empleo de PRP como alternativa de tratamiento viable para fracturas que presenten no unión en perros