Tuning structural control devices with genetic algorithms for a floating wind turbine

Floating offshore wind turbines present several advantages over land-based and bottom-fixed offshore wind turbines, but they are also exposed to strong environmental loads, especially wind and waves, which generate vibrations in the structure and compromise their efficiency and useful life. In this paper, a simplified theoretical model of a barge-type 5MW floating offshore wind turbine is developed and validated with reference software FAST, and used to study the effects of structural control. A tuned mass damper (TMD) is tuned using genetic algorithms for free decay different pitch angles of the platform, which could simulate different heights of waves impacting the turbine, with the goal of reducing the fore-aft tower top displacement. The proposed structural control improves the dynamic response of the system, with a vibration suppression rate of 34.9%.Peer Reviewe

Evaluación de los aprendizajes en las asignaturas de las cátedras del Programa de Enseñanza de la Matemática y cátedra de Ciencias Químicas, 2020-2022

Las cátedras del Programa de Enseñanza de la Matemática y la cátedra de Ciencias Químicas experimentaron una transformación en su modelo educativo a partir del primer cuatrimestre del 2020 debido a la pandemia. Estos cambios afectaron la mediación pedagógica y la evaluación de los aprendizajes, lo que llevó a un papel central de los apoyos virtuales y los materiales digitales. En general, estas acciones fueron bien valoradas por los estudiantes, quienes reconocieron los esfuerzos de las cátedras en los foros de las asignaturas. Sin embargo, la evaluación de los aprendizajes presentó desafíos al trasladar los instrumentos del formato físico al formato digital mientras se mantenía la confiabilidad y validez. La digitalización también condujo a problemas de plagio y fraude académico, que en algunos casos fueron tratados por las autoridades académicas. Ante esta situación, se diversificaron los instrumentos de evaluación, incorporando métodos auténticos además de los tradicionales. De esta manera, el propósito es presentar los ajustes realizados en los modelos de evaluación de los aprendizajes en las asignaturas, así como compartir la experiencia en las pruebas escritas virtuales. Se busca valorar los aspectos positivos y aprovecharlos, pero también exponer las dificultades y riesgos asociados con la evaluación virtual, especialmente en términos de calidad educativa

Neuromonitoring depth of anesthesia and its association with postoperative delirium

Delirium after surgery or Postoperative delirium (POD) is an underdiagnosed entity, despite its severity and high incidence. Patients with delirium require a longer hospital stay and present more postoperative complications, which also increases hospital costs. Given its importance and the lack of specific treatment, multifactorial preventive strategies are evidenced based. Our hypothesis is that using general anaesthesia and avoiding the maximum time in excessively deep anaesthetic planes through BIS neuromonitoring device will reduce the incidence of postoperative delirium in patients over the age of 65 and their hospitalization stay. Patients were randomly assigned to two groups: The visible BIS group and the hidden BIS neuromonitoring group. In the visible BIS group, the depth of anaesthesia was sustained between 40 and 60, while in the other group the depth of anaesthesia was guided by hemodynamic parameters and the Minimum Alveolar Concentration value. Patients were assessed three times a day by research staff fully trained during the 72 h after the surgery to determine the presence of POD, and there was follow-up at 30 days. Patients who developed delirium (n = 69) was significantly lower in the visible BIS group (n = 27; 39.1%) than in the hidden BIS group (n = 42, 60.9%; p = 0.043). There were no differences between the subtypes of delirium in the two groups. Patients in the hidden BIS group were kept for 26.6 ± 14.0 min in BIS values < 40 versus 11.6 ± 10.9 min (p < 0.001) for the patients in the visible BIS group. The hospital stay was lower in the visible BIS group 6.56 ± 6.14 days versus the 9.30 ± 7.11 days (p < 0.001) for the hidden BIS group, as well as mortality; hidden BIS 5.80% versus visible BIS 0% (p = 0.01). A BIS-guided depth of anaesthesia is associated with a lower incidence of delirium. Patients with intraoperative neuromonitoring stayed for a shorter time in excessively deep anaesthetic planes and presented a reduction in hospital stay and mortality

Los primeros tiempos de Cuba en la ruta antillana del café

The author analizes the historical process of Cuban coffee along two and a half centuries (until the end of Spanish colonial era), its transformation in a international commoditie from the end of XVIIIth century (after Saint Domingue revolution), its phases, the coffee cultivated land dismiss for sugar production and coffee popular difussion in Cuban cities and villages.En el presente artículo se da a conocer el proceso cafetalero en Cuba durante siglo y medio de actividad (desde su introducción al fin del dominio español sobre la isla), su transformación en objeto de comercio internacional desde finales del siglo XVIII tras la destrucción de Saint Domingue, sus etapas de auge y decadencia en la isla, el abandono de sus tierras de cultivo en favor del azúcar y la rápida difusión de su ingesta por la población de ciudades y pueblos de Cuba

The global abundance of tree palms

Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests

Fast demographic traits promote high diversification rates of Amazonian trees

The Amazon rain forest sustains the world's highest tree diversity, but it remains unclear why some clades of trees are hyperdiverse, whereas others are not. Using dated phylogenies, estimates of current species richness and trait and demographic data from a large network of forest plots, we show that fast demographic traits - short turnover times - are associated with high diversification rates across 51 clades of canopy trees. This relationship is robust to assuming that diversification rates are either constant or decline over time, and occurs in a wide range of Neotropical tree lineages. This finding reveals the crucial role of intrinsic, ecological variation among clades for understanding the origin of the remarkable diversity of Amazonian trees and forests

EDUCACIÓN AMBIENTAL Y SOCIEDAD. SABERES LOCALES PARA EL DESARROLLO Y LA SUSTENTABILIDAD

Este texto contribuye al análisis científico de varias áreas del conocimiento como la filosofía social, la patología, la educación para el cuidado del medio ambiente y la sustentabilidad que inciden en diversas unidades de aprendizaje de la Licenciatura en Educación para la Salud y de la Maestría en Sociología de la SaludLas comunidades indígenas de la sierra norte de Oaxaca México, habitan un territorio extenso de biodiversidad. Sin que sea una área protegida y sustentable, la propia naturaleza de la región ofrece a sus visitantes la riqueza de la vegetación caracterizada por sus especies endémicas que componen un paisaje de suma belleza

Educación ambiental y sociedad. Saberes locales para el desarrollo y la sustentabilidad

EL LIBRO PERMITE REFLEXIONAR SOBRE LA IMPORTANCIA DE FOMENTAL LA EDUCACIÓN AMBIENTAL PARA RESOLVER LA PROBLEMÁTICA AMBIENTALEL LIBRO PRESENTA DIFERENTES TRABAJOS QUE ESTUDIAN EL TEMA D ELA SUSTENTABILIDAD, ENFATIZANDO LA IMPORTANCIA DE LA EDUCACIÓN AMBIENTAL Y LA TRANSDISCIPLINANINGUN

Sensitivity of South American tropical forests to an extreme climate anomaly

The tropical forest carbon sink is known to be drought sensitive, but it is unclear which forests are the most vulnerable to extreme events. Forests with hotter and drier baseline conditions may be protected by prior adaptation, or more vulnerable because they operate closer to physiological limits. Here we report that forests in drier South American climates experienced the greatest impacts of the 2015–2016 El Niño, indicating greater vulnerability to extreme temperatures and drought. The long-term, ground-measured tree-by-tree responses of 123 forest plots across tropical South America show that the biomass carbon sink ceased during the event with carbon balance becoming indistinguishable from zero (−0.02 ± 0.37 Mg C ha −1 per year). However, intact tropical South American forests overall were no more sensitive to the extreme 2015–2016 El Niño than to previous less intense events, remaining a key defence against climate change as long as they are protected