Una nueva hipótesis sobre la sucesión de los bosques tropicales húmedos y secos

In this paper 221 forest trees are grouped according to their habitat preferences into species preferring humid or dry and/or saline habitats or indifferent to the habitat type. Eleven functional traits classes (seeds per tree, seed size, seed weight, seeds per fruit, tolerance to shade, selectivity to habitat, sclerophylly, wood density, foliar area, tree height and tree volume) are arranged 1 to 4 according to a successional gradient. The strategies of forest trees are identified by analyzing the species matrices for humid forest ecosystems (joining species preferring humid habitats together with those indifferent to the habitat type) and for dry and/or saline ecosystems (joining species preferring dry and/or saline habitats and the ones indifferent to the habitat type). Both matrices are processed using the average taxonomic distance as the interval coefficient and by clustering analysis to discover successional organization patterns. The complexity of r-K continuum is discussed by focusing the K behavior of some variables among Pioneers (commonly r strategists) or the r behavior of some variables among Stabilizers (commonly K strategists). A new system of classification is presented as a hypothesis for discovering successional patterns in tropical forests.En el presente artículo agrupamos 221 especies forestales sobre la base de sus preferencias por tipos de hábitat húmedo o seco y/o salino, considerando aparte aquellas que son indiferentes al tipo de hábitat. El sistema de clasificación se sustentó en el empleo de clases de 11 variables funcionales (semillas por árbol, tamaño de las semillas, peso de las semillas, semillas por fruto, tolerancia a la sombra, selectividad al hábitat, esclerofilia, densidad de la madera, área foliar, altura del árbol y volumen del árbol) ordenadas de 1 a 4 de acuerdo con un gradiente sucesional. Las estrategias de las especies arbóreas se identificaron mediante el análisis de las matrices para ecosistemas forestales húmedos (uniendo las especies que prefieren hábitat húmedo con las que son indiferentes al tipo de hábitat) y para ecosistemas secos y/o salinos (uniendo las especies que prefieren hábitat seco y/o salino con las que son indiferentes al tipo de hábitat). Ambas matrices fueron procesadas mediante el uso del coeficiente de distancia taxonómica promedio y por análisis de clasificación para descubrir los patrones de organización sucesional. Se discutieron la complejidad del continuum r-K exponiendo el comportamiento K de algunas variables entre las Pioneras (que comúnmente son estrategas r) y el comportamiento r de algunas variables entre las Estabilizadoras (que comúnmente son estrategas K). Presentamos el nuevo sistema de clasificación como una hipótesis para descubrir los patrones sucesionales en bosques tropicales.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEInternational Foundation for Science (IFS) (Sweden)MacArthur Foundation and D. W. Reynolds Foundation (USA)David Rockefeller Center for Latin-American Studies (Cambridge, USA)The Ecological Society of America (ESA)( Washington, USA)pu

Re: "Mortality Attributed to COVID-19 in High-Altitude Populations" by Woolcott and Bergman

Carta al editorRevisión por pare

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Diseño y construcción de un salón para laboratorio de la mecánica de suelos de la Universidad Francisco de Paula Santander Cread-Ocaña

El trabajo trata acerca del diseño y construcción de un salón para el laboratorio de mecánica de suelos de la universidad Francisco de Paula Santander Cread Ocaña. Se plantea Diseñar y Construir el Salón para el Laboratorio de Mecánica de Suelos para la Universidad Francisco de Paula Santander – Cread Ocaña. Para ello, primeramente se Solicita a las directivas de la Institución Educativa Instituto Técnico Industrial la cesión de los terreros para la construcción de un salón para el funcionamiento del laboratorio de Mecánica de suelos para la universidad Francisco de Paula Santander – Cread Ocaña. Seguido de, Gestionar ante entes públicos y privados los recursos necesarios para la construcción de un salón para el funcionamiento del Laboratorio de Mecánica de Suelos. Para luego, Diseñar los planos necesarios para la construcción de un salón para el funcionamiento del laboratorio de suelos. Y finalmente, Entregar a las directivas de la Universidad Francisco de Paula Santander – Cread Ocaña, el Salón para el funcionamiento del Laboratorio de Mecánica de suelos.PregradoTecnólogo(a) en Obras Civile

COVID-19 mortality is attenuated at high tropical and subtropical altitude : an observational study of a database covering five Latin American countries

Pacientes con COVID-19The COVID-19 pandemic, caused by the SARS-COV-2 virus, has had devastating consequences worldwide. Remarkably, the incidence, virus transmission capacity, and severity of COVID-19 have been reported to be significantly decreased in high-altitude human populations. The clinical significance of these findings is enormous, as they suggest that permanent inhabitants of high altitudes have developed adaptive protective changes against certain pathologies. However, these observations have been overshadowed by contradictory reports on the COVID-19 mortality rate at high altitude, ascribed to low population densities. These interpretations, however, fail to consider that the environmental conditions of high-altitude regions of the temperate and tropical geographical zones are radically different from each other. Contrary to common thought, the conditions of high-altitude areas of countries within the tropical zone are so benign that they have favored the growth and development of densely populated cities. In this work, we use data from a COVID-19 database covering five Latin American countries in the tropical and subtropical geographic zone that corresponded to the period between the start of the pandemic and the end of 2020, when no vaccine was yet available. Our results reveal that residing above 1,000 m in tropical countries was a protective factor against COVID-19 mortality. Interestingly, this protective effect was independent of population size. The findings presented here, and those from other similar studies, substantiate the need for more research to reveal the secrets of the physiology of permanent high-altitude residents. In conclusion, our findings clearly demonstrate that the high-altitude environment in tropical and subtropical geographic zones significantly contributes to the decreased mortality impact of the SARS-COV-2 virus in high-altitude-exposed populations.https://orcid.org/0000-0002-0100-1940Revista Internacional - No indexadaN

COVID-19 case fatality rate is significantly reduced in high-altitude Andean populations of Bolivia, Colombia, Ecuador, Perú; and México in an ecological study

Previous epidemiological studies have shown that the incidence and severity of COVID-19 decrease significantly with high altitude. To date, the impact of high altitude on mortality caused by COVID-19 remains debated. This work evaluated the impact of high altitude residency on COVID-19 mortality and recovery rates in several Andean countries and México. For this purpose, a multinational ecological study of official data from Bolivia, Peru, Colombia, Ecuador, and Mexico was performed from the beginning of the pandemic until the end of 2020. The case fatality rate (CFR) of populations above 2,500 m and below 1,000 m was compared. Our results show that CFR decreases, and there is a higher recovery rate in populations located above 2,500 m in all five countries. Based on this study and multiple other references, we conclude that mortality caused by COVID-19 is lower in high-altitude Andean populations, and in the high-altitude municipalities of Mexico than in the lowlands of all these countries

Anuario del Centro de Estudios Martianos (Vol. 39 2016)

El Anuario del Centro de Estudios Martianos es la publicación insignia de esta institución y heredera directa del Anuario Martiano de la Biblioteca Nacional José Martí, que se publicó entre 1969 y 1977, bajo la dirección del poeta y ensayista Cintio Vitier.<br> Desde que salió a la luz su primera entrega, en 1978, se han publicado treinta y cinco números, en los que aparecen artículos y ensayos de importantes estudiosos de la vida y obra del Apóstol, en Cuba y el resto del mundo.<br> En sus secciones fijas (Otros textos de José Martí, Documentos, Estudios y aproximaciones, Vigencias, Publicaciones, Bibliografía, Constante) y los apartados especiales, los lectores pueden conocer disímiles temas del quehacer martiano internacional, en el año que termina además de mantenerse al tanto de las últimas contribuciones de los promotores e investigadores de la obra martiana en el orbe