ABSTRACT
The luminosity of stripped-envelope supernovae, a common type of stellar explosion, is believed to be mainly driven by the radioactive decay of the nickel synthesized in the explosion and carried in its ejecta. Additional possible energy sources have been previously suggested1-5, in which the two most observationally based results have been from a comparison of the observed time-weighted luminosity with the inferred radioactive power1 and from a comparison of the light curves with particular theoretical models3. However, the former result1 was not statistically significant, and the latter3 is highly dependent on the specific models assumed. Here we analyse the energy budget of a sample of 54 well-observed stripped-envelope supernovae of all sub-types and present statistically significant, largely model-independent, observational evidence for a non-radioactive power source in most of them (and possibly in all). We consider various energy sources, or alternatively, plausible systematic errors, that could drive this result, and conclude that the most likely option is the existence of a long-lived central engine, operating over ≈103-106 s after the explosion. We infer, from the observations, constraints on the engine properties. If, for example, the central engine is a magnetized neutron star, then the initial magnetic field is ≈1015 G and the initial rotation period is 1-100 ms, suggesting that stripped-envelope supernovae may constitute the formation events of the objects known as magnetars.
ABSTRACT
RESUMEN El municipio Jagüey Grande, en la provincia de Matanzas, tuvo una activa participación en la Guerra de Independencia (1895-1898). En ese contexto, el médico José Lázaro Martín Marrero Rodríguez fue designado delegado del Partido Revolucionario Cubano en el territorio; su consagración fue decisiva para al movimiento independentista de esa localidad. El presente trabajo reseña las cualidades del doctor Marrero Rodríguez, a través de pasajes de su vida como organizador revolucionario en Jagüey Grande. Se argumenta sobre sus relaciones con José Martí, sus habilidades como estratega militar en el combate de Palmar Bonito y su contribución científica. El doctor Marrero fue reconocido como Hijo Distinguido de Santiago de las Vegas (La Habana) y como Hijo Adoptivo de Jagüey Grande, por sus méritos al servicio de la Patria. El hogar materno de Jagüey Grande lleva su nombre. Su vida, pensamiento y trayectoria, consagrados a la independencia de Cuba, constituyen un paradigma a seguir.
ABSTRACT People from the municipality of Jagüey Grande, in the province of Matanzas, took active part in the Independence War (1895-1898). In that context, physician Jose Lazaro Martin Marrero Rodriguez was appointed delegate of the Cuban Revolutionary Party in the territory; his consecration was decisive for the independence movement of the town. The current work reviews Dr. Marrero Rodriguez's qualities, through passages of his life as revolution organizer in Jaguey Grande. The article tells about his relationship with Jose Marti, his skills as military strategist in the combat of Palmar Bonito and his scientific contribution. Dr. Marrero was recognized as Distinguished Son of Santiago de las Vegas (La Habana) and Adoptive Son of Jaguey Grande, due to his merits at the service of the Homeland. The Maternal Home of Jaguey Grande is named after him. His life, thoughts and curriculum, devoted to Cuban independence, are a paradigm to follow.
ABSTRACT
RESUMEN El neumomediastino espontáneo se caracteriza por la presencia de aire en el mediastino. Es una enfermedad generalmente benigna, que evoluciona de forma satisfactoria entre 2 y 15 días, no asociada a causa directa conocida. Es infrecuente en la tercera edad. Se presenta principalmente con dolor torácico, disnea y enfisema subcutáneo. El diagnóstico se realiza sobre la base del cuadro clínico, la radiografía de tórax y la tomografía axial computarizada de tórax, siendo esta última importante, además, para establecer el diagnóstico diferencial con el síndrome de Boerhaave de manera oportuna. Se presentó el caso de un paciente masculino de 67 años de edad, fumador con antecedente de enfermedad pulmonar obstructiva crónica, que acude al cuerpo de guardia por dolor torácico, disnea y enfisema subcutáneo después de un episodio de tos intensa. Se le realizaron radiografías de tórax posteroanterior y lateral, en las que se observan la presencia de aire en el mediastino, se descartan otras enfermedades agudas, y se corrobora el diagnóstico de neumomediastino mediante tomografía axial computarizada de tórax. Recibió tratamiento con oxígeno, broncodilatadores, esteroides y antibióticoterapia, obteniéndose una mejoría evidente. La literatura reporta que no es habitual la presencia de este cuadro en pacientes de la tercera edad, y que debe sospecharse en aquellos que presenten una exacerbación de la enfermedad pulmonar obstructiva crónica, fundamentalmente después de un episodio de tos.
ABSTRACT The spontaneous pneumomediastinum is characterized by the air presence in the mediastinum. It is a generally benign disease which evolves in a satisfactory way between 2 and 15 days, that is not associated to any directly known cause. It is infrequent in the old age. It mainly presents with chest pain, dyspnea and subcutaneous emphysema. Diagnosis realizes on the base of clinical characteristics, thorax radiography and thorax axial computed tomography, being the last one also important to establish the differential diagnosis with Boerhaave syndrome in an opportune way. The case presented is the case of a male patient aged 67 years, who smokes and has antecedents of chronic obstructive pulmonary disease. He assisted to the consultation due to thoracic pain, dyspnea and subcutaneous emphysema after an episode of intense cough. Posteroanterior and lateral thorax radiography were done, finding air presence in the mediastinum; other acute diseases were discarded and the diagnosis of pneumomediastinum was corroborated through thorax computed tomography scan. He was treated with oxygen, bronchodilators, steroids and antibiotics therapy, obtaining an evident improvement. The literature reports that the presence of these characteristics in old-aged patients is not common and that it must be suspected in those presenting an aggravation of the chronic obstructive pulmonary disease, mainly after a cough episode.
