Caracterización y análisis de las sequías y olas de calor (1977-2020) en Talca

47 p.La zona central del país ha sido abatida por eventos de sequías en varias oportunidades, encontrándose actualmente afectada por una megasequía que comenzó el año 2007, la cual trajo consigo un déficit en las precipitaciones y un alza considerada en las temperaturas. La región del Maule es la segunda región con mayor producción agrícola del país y se encuentra propensa a sequias invernales y el desarrollo de olas de calor, es decir una reducción recurso hídrico. Esto ha generado una disminución de la producción agrícola debido a la falta de agua. El objetivo de este estudio es entregar un análisis del comportamiento de las temperaturas y precipitaciones abarcando entre 1977-2020, para la ciudad de Talca. Los resultados señalaron que existe un aumento en el número de olas de calor y eventos cálidos del siglo pasado en comparación con el siglo XXI. Por su parte las precipitaciones han ido en descenso los últimos 120 años, produciéndose en este último siglo un 61.9% de meses más secos por sobre los húmedos, todo esto en conjunto de la sequía más larga (14 años a la fecha), más intensa (intensidad media 162.2 mm) y de mayor magnitud (2270.6 mm) en la historia de la ciudad. La correlación del aumento en las temperaturas y la presión superficial del mar se reduce de un 46% a un 2% en comparación con el siglo anterior, demostrando la inestabilidad climática y preponderancia del cambio climático por sobre los fenómenos ENOS. Los resultados muestran que las variables del clima se han visto alteradas en su normalidad producto de la sequía que se atraviesa, por lo cual un análisis de las variables climáticas es una herramienta importante para los agricultores nacionales. // ABSTRACT: The central zone of the country has been hit by drought events on several occasions, and is currently affected by a megadrought that began in 2007, which brought with it a deficit in rainfall and a significant rise in temperatures. The Maule region is the second region with the highest agricultural production in the country and is prone to winter droughts and heat waves, it means a reduction in water resources. This has led to a decrease in agricultural production due to the lack of water. The objective of this study is to provide an analysis of the behavior of temperatures and precipitation between 1977-2020 for the city of Talca. The results indicated that there is an increase in the number of heat waves and hot events in the last century compared to the 21st century. Precipitation has been decreasing over the last 120 years, with 61.9% drier than wetter months in the last century, all this in conjunction with the longest (14 years to date), most intense (average intensity 162.2) and largest drought (2270.6) in the history of the city. The correlation of the increase in temperatures and sea surface pressure is reduced from 46% to 2% compared to the previous century, demonstrating the climatic instability and preponderance of climate change over ENSO phenomena. The results show that climate variables have been altered in their normality as a result of the current drought, which is why an analysis of climate variables is an important tool for national farmers

Abnormal EEG signal energy in the elderly: a wavelet analysis of event-related potentials during a stroop task

Background: Previous work showed that elderly with excess in theta activity in their resting state electroencephalogram (EEG) are at higher risk of cognitive decline than those with a normal EEG. By using event-related potentials (ERP) during a counting Stroop task, our prior work showed that elderly with theta excess have a large P300 component compared with normal EEG group. This increased activity could be related to a higher EEG signal energy used during this task. New method: By wavelet analysis applied to ERP obtained during a counting Stroop task we quantified the energy in the different frequency bands of a group of elderly with altered EEG. Results: In theta and alpha bands, the total energy was higher in elderly subjects with theta excess, specifically in the stimulus categorization window (258–516 ms). Both groups solved the task with similar efficiency. Comparison with existing methods: The traditional ERP analysis in elderly compares voltage among conditions and groups for a given time window, while the frequency composition is not usually examined. We complemented our previous ERP analysis using a wavelet methodology. Furthermore, we showed the advantages of wavelet analysis over Short Time Fourier Transform when exploring EEG signal during this task. Conclusions: The higher EEG signal energy in ERP might reflect undergoing neurobiological mechanisms that allow the elderly with theta excess to cope with the cognitive task with similar behavioral results as the normal EEG group. This increased energy could promote a metabolic and cellular dysregulation causing a greater decline in cognitive function.Instituto de Física La Plat

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation

Anales del III Congreso Internacional de Vivienda y Ciudad "Debate en torno a la nueva agenda urbana"

Acta de congresoEl III Congreso Internacional de Vivienda y Ciudad “Debates en torno a la NUEVa Agenda Urbana”, ha sido una apuesta de alto compromiso por acercar los debates centrales y urgentes que tensionan el pleno ejercicio del derecho a la ciudad. Para ello las instituciones organizadoras (INVIHAB –Instituto de Investigación de Vivienda y Hábitat y MGyDH-Maestría en Gestión y Desarrollo Habitacional-1), hemos convidado un espacio que se concretó con potencia en un debate transdisciplinario. Convocó a intelectuales de prestigio internacional, investigadores, académicos y gestores estatales, y en una metodología de innovación articuló las voces académicas con las de las organizaciones sociales y/o barriales en el Foro de las Organizaciones Sociales que tuvo su espacio propio para dar voz a quienes están trabajando en los desafíos para garantizar los derechos a la vivienda y los bienes urbanos en nuestras ciudades del Siglo XXI

Two Different Populations within the Healthy Elderly: Lack of Conflict Detection in Those at Risk of Cognitive Decline

During healthy aging, inhibitory processing is affected at the sensorial, perceptual, and cognitive levels. The assessment of event-related potentials (ERPs) during the Stroop task has been used to study age-related decline in the efficiency of inhibitory processes. Studies using ERPs have found that the P300 amplitude increases and the N500 amplitude is attenuated in healthy elderly adults compared to those in young adults. On the other hand, it has been reported that theta excess in resting EEG with eyes closed is a good predictor of cognitive decline during aging 7 years later, while a normal EEG increases the probability of not developing cognitive decline. The behavioral and ERP responses during a Counting-Stroop task were compared between 22 healthy elderly subjects with normal EEG (Normal-EEG group) and 22 healthy elderly subjects with an excess of EEG theta activity (Theta-EEG group). Behaviorally, the Normal-EEG group showed a higher behavioral interference effect than the Theta-EEG group. ERP patterns were different between the groups, and two facts are highlighted: (a) the P300 amplitude was higher in the Theta-EEG group, with both groups showing a P300 effect in almost all electrodes, and (b) the Theta-EEG group did not show an N500 effect. These results suggest that the diminishment in inhibitory control observed in the Theta-EEG group may be compensated by different processes in earlier stages, which would allow them to perform the task with similar efficiency to that of participants with a normal EEG. This study is the first to show that healthy elderly subjects with an excess of theta EEG activity not only are at risk of developing cognitive decline but already have a cognitive impairment

El efecto pantalla o sombra de los árboles en la formación de los escurrimientos urbanos

La funcionalidad del bosque urbano depende de la intensidad y el ángulo de incidencia de la precipitación, la capacidad de intercepción, la velocidad y dirección del viento, y la ubicación espacial de los árboles. El efecto de pantalla de la vegetación urbana es una condicionante de la generación de los escurrimientos urbanos, de la eficiencia del sistema de drenaje y de los niveles de contaminación ocasionados por el lavado de contaminantes de calles y avenidas. En este trabajo se investiga el efecto de pantalla o sombra en la generación de los escurrimientos urbanos en torno a un árbol aislado de la especie Ficus benjamina L. El flujo de intercepción fue medido con base en el sistema desarrollado por Guevara- Escobar et al. (2006) construido con plástico transparente; en este caso, el plástico fue sustituido por policarbonato transparente, con el fin de reducir las pérdidas producida por la fuerza y turbulencia del viento. El volumen acumulado en los 88 eventos fue de 21.36 m3 (sin árbol); considerando la pérdida por intercepción, se redujo a 6.97 m3, una diferencia de 14.39 m3. El gasto calculado con la precipitación (Pg) fue de 30.51 m3s-1, el cual se redujo 8.49 m3s-1, al considerar las pérdidas por intercepción. Con la relación propuesta por David et al. (2006), las características morfológicas de la especie Ficus benjamina, así como su arquitectura, se encontró que la distancia del efecto pantalla llega a ser de 4.43 m. La diferencia entre el gasto originado y la precipitación neta Pn fue de 22.01 m3s-1. Los resultados muestran que la funcionalidad del bosque urbano como estructura de control-obstrucción y su beneficio en la generación de los escurrimientos urbanos depende de su ubicación espacial dentro de una zona urbana

Two Different Populations within the Healthy Elderly: Lack of Conflict Detection in Those at Risk of Cognitive Decline

During healthy aging, inhibitory processing is affected at the sensorial, perceptual, and cognitive levels. The assessment of event-related potentials (ERPs) during the Stroop task has been used to study age-related decline in the efficiency of inhibitory processes. Studies using ERPs have found that the P300 amplitude increases and the N500 amplitude is attenuated in healthy elderly adults compared to those in young adults. On the other hand, it has been reported that theta excess in resting EEG with eyes closed is a good predictor of cognitive decline during aging 7 years later, while a normal EEG increases the probability of not developing cognitive decline. The behavioral and ERP responses during a Counting-Stroop task were compared between 22 healthy elderly subjects with normal EEG (Normal-EEG group) and 22 healthy elderly subjects with an excess of EEG theta activity (Theta-EEG group). Behaviorally, the Normal-EEG group showed a higher behavioral interference effect than the Theta-EEG group. ERP patterns were different between the groups, and two facts are highlighted: (a) the P300 amplitude was higher in the Theta-EEG group, with both groups showing a P300 effect in almost all electrodes, and (b) the Theta-EEG group did not show an N500 effect. These results suggest that the diminishment in inhibitory control observed in the Theta-EEG group may be compensated by different processes in earlier stages, which would allow them to perform the task with similar efficiency to that of participants with a normal EEG. This study is the first to show that healthy elderly subjects with an excess of theta EEG activity not only are at risk of developing cognitive decline but already have a cognitive impairment

NETLAB: teleobservatorio universitario de docencia virtual

El proyecto Net.Lab pretende crear un espacio de referencia en la red que facilite la incorporación de las TIC en el ámbito universitario a partir de la definición de unos criterios de calidad

Association between ABO blood groups and preeclampsia

Objective To determine the association between the ABO blood group and preeclampsia. Methods This is a case-control study that included patients with (n = 253) and without (n = 457) preeclampsia/eclampsia in Northeastern Mexico. Data were obtained from electronic medical records. Binary multiple logistic regression analysis was used for analyzing the association between the ABO blood group and preeclampsia according to parity status while adjusting for potential confounders. Results Blood groups A, B, and AB showed adjusted odds ratios of 0.6 (95%CI 0.3-1.0), 1.1 (95%CI 0.6-2.2), and 0.3 (95%CI 0.1-1.1) in multiparous women, respectively. No association was found in nulliparous women either. Conclusions ABO blood groups were not associated with preeclampsia in Mexican women