RESUMEN Entre 23 y 27 de enero de 2020 se registró la presencia de una ballena de aleta (Balaenoptera physalus) en aguas costeras del área marina protegida del Parque Nacional Natural Corales del Rosario y de San Bernardo. Este es el primer registro de un animal vivo para el mar Caribe colombiano. Aunque no fue posible establecer relaciones de causalidad, la presente nota incluye una descripción del contexto ambiental y oceanográfico asociado a los avistamientos. Si bien el Caribe colombiano, por sus características oligotróficas, no soportaría consistentemente la presencia de los grandes rorcuales, se sugiere incluirlo como parte del rango de distribución potencial de la ballena de aleta. El presente registro también resalta la importancia y relevancia de los procesos de ciencia ciudadana y participativa, además del trabajo interinstitucional y colaborativo, acciones clave para el monitoreo de especies de alta movilidad como los mamíferos marinos.

ABSTRACT Between January 23rd and 27th, 2020, a Fin whale (Balaenoptera physalus) was seen in coastal waters of the Rosario and San Bernardo Corals National Natural Park. This is the first known record of a live animal for the Colombian Caribbean Sea. While it was not possible to establish causality relationships, the present note includes a description of the environmental and oceanographic context associated with sightings. While the Colombian Caribbean, because of its oligotrophy, would not permanently sustain a constant presence of the great baleen whales, its inclusion as part of the potential distribution range for Fin whales is suggested. The current report also highlights the importance and relevance of citizen science, in addition to interinstitutional and collaborative work, key processes for the monitoring of high mobility species such as marine mammals.

Abstract: This article analyzes the prospects of economic viability of installing photovoltaic systems connected to the network in homes of the city of Arica (Chile). Installation would allow residents to generate an additional income source by selling electricity surpluses while saving on electricity consumption and reducing CO2 emissions. The proposed methodology is based on the characterization of the average house in the city of Arica and on the subsequent dimensioning and profitability analysis of the photovoltaic system to be installed. This includes the economic, technical, legal, and environmental aspects related to the installation of photovoltaic systems. The results show that photovoltaic systems were profitable in the Arica homes included in this study. In conclusion, the implementation of photovoltaic systems as a source of distributed power generation is a viable project in Arica homes.

Resumen: Este artículo analiza las perspectivas de viabilidad económica de instalación de sistemas fotovoltaicos conectados a la red en viviendas de la ciudad de Arica en Chile. Dicha instalación permite al residente de la vivienda generar ingresos mediante la venta de excedentes de energía eléctrica y el ahorro de consumo eléctrico, además de disminuir las emisiones de CO2. La metodología propuesta del estudio se basa en la caracterización de la vivienda promedio de la ciudad de Arica y en el posterior dimensionamiento y análisis de rentabilidad del sistema fotovoltaico a instalar. Se consideran los aspectos económicos, técnicos, legales y ambientales vinculados a la instalación de sistemas fotovoltaicos. Los resultados obtenidos indican que la implementación de sistemas fotovoltaicos como fuente de generación de energía distribuida para las viviendas de la ciudad de Arica, es un proyecto viable, ya que este es rentable a lo largo del periodo analizado.

Abstract Objective: To determine the epidemiological characteristics, treatment, reperfusion strategies and in-hospital adverse events of patients with ST elevation myocardial infarction in Peru. Methods: Observational, prospective multicentre study in patients over 18 years admitted to hospital with a diagnosis of ST elevation myocardial infarction. Results: A total of 396 patients were enrolled in the registry during February 2016 to February 2017. The mean age was 64.9 ± 12 years, and 21% were women. In the first 12 h of onset 38% of patients were fibrinolysed, 29% underwent primary PCI, and 33% did not receive any reperfusion. Pharmaco-invasive strategy was used in 12.9% of cases. The fibrinolysis was successful in 65% of patients, and primary PCI success was 82%. The hospital stay was 6 days (IQR 5-10). In-hospital mortality was 10.1%, with the first cause of death being due to cardiogenic shock. The rate of in-hospital re-infarction was 2.2%, and the rate of acute heart failure was 25%. Age > 75 years, large infarct size, left ventricular ejection fraction < 40%, and absence of negative T waves on post-reperfusion electrocardiogram were independently related to higher in-hospital mortality. Conclusions: In Peru, ST elevation myocardial infarction most frequently affects men between 60-70 years. The most frequent initial reperfusion treatment is fibrinolysis, followed by primary angioplasty, and pharmaco-invasive strategy. The main reason for the lack of administration of reperfusion treatment was the delay from symptoms onset to first medical contact. The most common cause of in-hospital death was cardiogenic shock.

Resumen Objetivo: Determinar las características epidemiológicas, el tratamiento, las estrategias de reperfusión y los eventos adversos intrahospitalarios de pacientes con infarto de miocardio con elevación del segmento ST en Perú. Métodos: Estudio observacional, prospectivo, multicéntrico a nivel nacional, en pacientes mayores de 18 años hospitalizados con diagnóstico de infarto de miocardio con elevación del segmento ST. Resultados: Desde febrero de 2016 a febrero de 2017, 396 pacientes fueron enrolados; la edad promedio fue de 64.9 ± 12 años y el 21% eran mujeres. En las primeras 12 h de evolución un 38% fueron fibrinolisados, en un 29% se realizó PCI primaria y un 33% no recibieron reperfusión. En el 12.9% se usó estrategia farmacoinvasiva. La tasa de éxito de la fibrinólisis fue de un 65% y la de la PCI primaria fue de un 82%. La estancia hospitalaria fue de 6 días (RIQ 5-10). La mortalidad intrahospitalaria llegó a un 10.1%, siendo la principal causa de muerte el choque cardiogénico. La tasa de reinfarto intrahospitalario fue de 2.2% y de falla cardiaca postinfarto, de 25%. La edad > 75 años, grandes tamaños de infarto, la fracción de eyección de ventrículo izquierdo < 40% y la ausencia de ondas T negativas en el electrocardiograma posreperfusión fueron variables relacionadas de manera independiente con una mayor mortalidad intrahospitalaria. Conclusiones: El infarto de miocardio con elevación del segmento ST en Perú afecta con más frecuencia a varones de entre 60 y 70 años. El tratamiento de reperfusión inicial más frecuente es la fibrinólisis, seguida por la angioplastia primaria y la estrategia farmacoinvasiva. El motivo principal de la falta de administración de tratamiento de reperfusión fue la demora desde el inicio de los síntomas hasta el primer contacto médico. La causa más frecuente de muerte intrahospitalaria es el choque cardiogénico.

Neste artigo são dados exemplos de toros T² mergulhados em S³ com todas as suas linhas assintóticas densas.

In this paper are given examples of tori T² embedded in S³ with all their asymptotic lines dense.

This paper pursues the study carried out by the authors in Stability and Hopf bifurcation in the Watt governor system [14], focusing on the codimension one Hopf bifurcations in the centrifugal Watt governor differential system, as presented in Pontryagin's book Ordinary Differential Equations, [13]. Here are studied the codimension two and three Hopf bifurcations and the pertinent Lyapunov stability coefficients and bifurcation diagrams, illustrating the number, types and positions of bifurcating small amplitude periodic orbits, are determined. As a consequence it is found a region in the space of parameters where an attracting periodic orbit coexists with an attracting equilibrium.

Neste trabalho são determinadas as curvaturas principais e as linhas de curvatura principal das superfícies canal que são as envoltórias de famílias de esferas com raios variáveis e centros deslocando-se ao longo de curvas fechadas regulares em R³. A partir de uma conexão com as equações de Riccati mostra-se que estas superfícies têm no máximo duas curvas principais periódicas isoladas. São dados exemplos com duas curvas principais periódicas simples e com uma dupla.

In this paper are determined the principal curvatures and principal curvature lines on canal surfaces which are the envelopes of families of spheres with variable radius and centers moving along a closed regular curve in R³. By means of a connection of the differential equations for these curvature lines and real Riccati equations, it is established that canal surfaces have at most two isolated periodic principal lines. Examples of canal surfaces with two simple and one double periodic principal lines are given.

Neste trabalho estuda-se o comportamento das linhas de curvatura principal próximas a uma curva de pontos umbílicos, numa superfície suave.

In this paper is studied the behavior of principal curvature lines near a curve of umbilic points of a smooth surface.

No espaço das formas cúbicas de superfícies, consideradas como um G-espaço e munido de uma métrica invariante, é avaliado o quociente dos volume das formas cúbicas correspondentes aos umbílicos de índice negativo pelo volume daquele correspondente aos umbíicos de índice positivo. Esta avaliação é expressa em termos da assimetria da métrica, definida neste artigo. Este trabalho contém também uma seção com referências a trabalhos relacionados aos pontos umbílicos e outra com uma comparação do quociente acima citado com o obtido em 1977 por Berry e Hannay no domínio da Física Estatística.

In the space of cubic forms of surfaces, regarded as a G-space and endowed with a natural invariant metric, the ratio of umbilic points with a negative index to those with a positive index is evaluated in terms of the asymmetry of the metric, defined here. This work contains also a section with references pertinent to umbilic points and one with a discussion of a connection of the above defined ratio with that reported in 1977 by Berry and Hannay in the domain of Statistical Physics.

Neste trabalho são estudadas as linhas de curvaturas principais de uma superfície com bordo e da superfície regular, sem bordo, obtida pelo processo de engrossamento e regularização. É analisada a relação entre as tangências quadráticas das folheações principais com o bordo e os pontos umbílicos Darbouxianos, da superfície sem bordo, que bifurcam dos referidos pontos de tangências.

In this paper is studied the relationship between quadratic tangencies of principal lines with the boundary of a surface and the Darbouxian umbilics of a smooth boundaryless surface which approximates it through the process of thickening and smoothing defined here.