Climate variability over the American monsoon and Amazonian regions during the last decades

textThis dissertation aims to identify the main changes in monsoon activity observed over the American monsoon and Amazonian regions during the last decades and the possible links between such changes. To address this, several observational and reanalysis datasets were used. The results suggest the occurrence of two regime types of the North American monsoon during 1948-2009: two dry regimes during 1948-1959 and 1990-2009 and one wet regime during 1960-1989. The occurrence of such regimes is modulated by the Atlantic Multidecadal Oscillation. However, the two dry regimes have different causes. In particular, the more recent dry regime is mainly due to both an anomalous westward expansion of the North Atlantic Subtropical High and a northward displacement of the subtropical jet stream over the United States. The former enhances the low-level flow from the Gulf of Mexico to the Great Plains and weakens moisture transport to Mexico and the southwestern US. In addition to such a weakening of the North American monsoon during the last two decades, this research shows that the American monsoon systems have shortened after 1978 due to a trend toward earlier retreats of the North American monsoon and delayed onsets of the southern Amazon wet season. These changes produce a longer transition season between both monsoon systems. Whether these changes are caused by a common factor or they are the consequence of independent and unrelated causes was not clear previously. The results discussed here indicate that the observed changes in the American monsoons are partially a consequence of the westward expansion of the North Atlantic surface high observed since 1978. Such a westward expansion enhances the activity of easterly waves over the southern Caribbean Sea and northern South America, producing a dominant easterly flow over the region, which in turn prevents the reversal of the cross-equatorial flow necessary to transport moisture to the southern Amazon and the South American monsoon domain and contributes to its delayed onset. This investigation provides evidence that the shortening and weakening of the American monsoons and the lengthening of the transition season between them are associated with the same large-scale forcing, which may be caused by anthropogenic influence.Geological Science

Lineamientos para reglamentar áreas estratégicas con problemas de contaminación atmosférica en la ciudad de medellín

El Material Particulado inferior a 2.5 micras (PM2.5) es el contaminante que presenta condiciones más críticas para Medellín y el Valle de Aburrá, ya que supera los límites indicados por la OMS. Para el Valle de Aburrá la emisión primaria de este material proviene en un 91% de las fuentes móviles, lo cual determina la necesidad de identificar lineamientos que permitan una oportuna intervención en aras de disminuir los niveles de concentración de contaminantes en zonas estratégicas como el centro de la ciudad de Medellín, donde se ha establecido una “Zona Urbana de Aire Protegido - ZUAP”, en este sentido se realiza la evaluación de dicha área a partir de documentos como el Plan de Ordenamiento Territorial y el Inventario de Emisiones para posteriormente proponer medidas que permitan cumplir el propósito de disminuir la contaminación atmosférica en esta zona y que a su vez influya en un disminución de emisiones de GEI. Las medidas propuestas parten del análisis realizado en ciudades europeas que han implementado Zonas de Bajas Emisiones, las cuales fueron evaluadas por parte de una selección de profesionales conocedores de la problemática en Medellín, permitiendo concluir sobre la importancia de invocar cambios modales, la optimización y el cambio tecnológico y la necesidad de contar con una política pública de movilidad sostenible que supere las intervenciones físico territoriales como la construcción de vías. También se evidencian las dificultades que se tienen al plantear medidas restrictivas, las cuales a pesar de ser efectivas resultan impopulares para la población.The particulate matter under 2.5 microns (PM2.5) is the pollutant that bear the most critical conditions for Medellín and the Aburrá Valley. This pollutant exceeds the limits indicated by the WHO. For the Aburrá Valley the 91% of the primary emission of this material comes from mobile sources. Thus, there is a necessity to identify guidelines for a timely intervention to reduce the concentration of pollutants in strategic areas such as the center of Medellín. In fact, the city has established a “Urban Protected Air Zone - ZUAP”. The evaluation of this area is carried out based on documents such as the Land Use Plan and the Emissions Inventory. Subsequently, measures to reduce air pollution and GHG emissions in the area were proposed. The proposed measures are based on analysis carried out in European cities that have developed Low Emission Zones (LEZ). These measures were evaluated by a selection of professionals with knowledge in Medellín’s issues. Hence, it ensues the importance to promote modal changes, as well as optimization and technological transformations. Also, the government shall develop a public policy in sustainable mobility that goes beyond physical-territorial interventions such as road construction. Finally, the difficulties encountered when proposing restrictive measures are also evident. Despite being effective measures, are unpopular within the community

Efecto de la desagregación temporal sobre la coherencia espacial de la precipitación en Colombia

RESUMEN: Se estudia el efecto de la variación de la escala temporal en el comportamiento de la precipitación en Colombia, mediante análisis de Funciones Ortogonales Empíricas (FOE) y de Transformada en Onditas, usando registros en tres escalas temporales: (i) mensuales durante el período Diciembre de 1976Febrero de 1996, en 41 estaciones de medición, (ii) diarios durante el período Noviembre 1982Enero de 1992, en 28 estaciones, y (iii) diarios filtrados en la banda intraestacional 20110 días, durante el período comprendido entre Noviembre 26 de 1982 y Enero 1 de 1992, en 28 estaciones. Los resultados para (i) muestran que la primera FOE explica el 90% de la varianza, lo que está asociado con la periodicidad anual y semianual de la oscilación meridional de la Zona de Convergencia Intertropical (ZCIT). La transformada en ondita de las primeras cuatro Componentes Principales (CP) muestran bandas espectrales significativas de 4 a 8 y 8 a 16 meses, cuya importancia relativa varía con el tiempo. Los resultados de (ii) muestran que la primera FOE explica el 28.4% de la varianza, y la segunda el 6.7%, requiriéndose 15 FOEs para explicar el 70% de la varianza total. El espectro en ondita muestra una banda significativa de 12025 días, asociada con el ciclo semianual, además de una banda de 864 días, que corresponde a la variabilidad intraanual asociada con las ondas del este y la oscilación de 3060 días (oscilación de MaddenJulian). Los resultados para (iii) indican que las tres primeras FOEs explican el 9.4%, 8.4% y 8.1% de la varianza, respectivamente, requiriéndose 15 FOEs para explicar el 70% de la varianza total. El espectro de potencias en ondita muestra bandas espectrales intermitentes significativas en el rango entre 2 y 120 días. Estos resultados evidencian la pérdida de estructura (coherencia espacial y regional) a medida que se disminuye la escala temporal de la precipitación en los Andes de Colombia

Precipitation over Northern South America and Its Seasonal Variability as Simulated by the CMIP5 Models

RESUMEN: Northern South America is identified as one of the most vulnerable regions to be affected by climate change. Furthermore, recent extreme wet seasons over the region have induced socioeconomic impacts of wide proportions. Hence, the evaluation of rainfall simulations at seasonal and interannual time scales by the CMIP5 models is urgently required.Here,we evaluated the ability of seven CMIP5models (selected based on literature review) to represent the seasonalmean precipitation and its interannual variability over northern SouthAmerica.Our results suggest that it is easier formodels to reproduce rainfall distribution during boreal summer and fall over both oceans and land. This is probably due to the fact that during these seasons, incoming radiation and ocean-atmosphere feedbacks over Atlantic and Pacific oceans locate the ITCZ on the Northern Hemisphere, as suggested by previous studies.Models exhibit the worse simulations during boreal winter and spring, when these processes have opposite effects locating the ITCZ. Our results suggest that the models with a better representation of the oceanic ITCZ and the local low-level jets over northern South America, such as the Choco low-level jet, are able to realistically simulate the main features of seasonal precipitation pattern over northern South America

Fortalecimiento de la motivación intrínseca de los estudiantes de quinto grado en la clase de inglés a través de la gamificación

La propuesta de investigación describe, analiza e ilustra una de las formas en que la gamificación puede usarse para mejorar la motivación intrínseca en la enseñanza del idioma inglés. El contexto escolar en el que se aplica esta intervención didáctica es el colegio Instituto técnico industrial Francisco José de Caldas. El curso objeto de esta propuesta es de quinto de primaria; más específicamente el grado 506. De esta población se toma una muestra significativa constituida por un grupo de 10 estudiantes.Universidad Libre- Facultad Ciencias de la Educación- Licenciatura en Español y Lenguas ExtranjerasThe research proposal describes, analyzes and illustrates one of the ways in which gamification can be used to improve intrinsic motivation in English language teaching. The school context in which this didactic intervention is applied is the school Instituto Técnico Industrial Francisco José de Caldas. The course object of this proposal is the fifth grade of primary school; more specifically, grade 506. From this population a significant sample is taken, consisting of a group of 10 students

An influence of extreme southern hemisphere cold surges on the North Atlantic Subtropical High through a shallow atmospheric circulation

ABSTRACT: Previous studies have attributed interhemisphere influences of the atmosphere to the latitudinal propagation of planetary waves crossing the equator, to the triggering of equatorial Kelvin waves, or to monsoonal circulation. Over the American-Atlantic sector, such cross-equatorial influences rarely occur during boreal summer due to unfavorable atmospheric conditions. We have observed that an alternative mechanism provides an interhemisphere influence. When episodes of extreme cold surges and upper tropospheric westerly winds occur concurrently over southern hemisphere Amazonia, cold surges from extratropical South America can penetrate deep into southern Amazonia. Although they do not appear to influence upper tropospheric circulation of the northern hemisphere, extremely strong southerly cross-equatorial advection (>2σ standard deviations, or 2) of cold and dense air in the lower troposphere can reach as least 10°N. Such cold advection increases the northward cross-equatorial pressure gradient in the lower to middle troposphere, thus shallow northerly return flow below 500 hPa. This return flow and the strong lower tropospheric southerly cross-equatorial flow form an anomalous shallow meridional circulation spanning from southern Amazonia to the subtropical North Atlantic, with increased geopotential height anomalies exceeding +1σ to at least 18°N. It projects onto the southern edge of the North Atlantic Subtropical High (NASH), increasing its pressure and leading to equatorward expansion of NASH’s southern boundary. These anomalies enhance the NASH, leading to its equatorward expansion. These extreme cold surges can potentially improving the predictability of weather patterns of the tropical and subtropical Atlantic, including the variability of the NASH’s southern edge

Nivel de satisfacción en relaciones románticas generadas mediante el uso de internet en jóvenes universitarios.

The present work is focused on identifying and evaluating levels of satisfaction in romantic relationships initiated by the internet. The objective was to assess whether the use of the Internet to initiate a romantic relationship had an effect on the degree of satisfaction experienced among university students. A questionnaire of 20 items was applied in a convenience sample to 633 university students, of whom 56% were women and 44% men; the age range was from 18 to 21 years, with validation by inclusion of 162 surveys. The degree of satisfaction was assessed using the scale of Hendrick and Hendrick (1992). The study shows that young people who have had romantic relationships in person, on average showed to be significantly more satisfied (F= 58.78; Pr > F= 0.0001) than those whose relationships were initiated through the internet. It was also showed that the satisfaction is linked with the socioeconomic level; there is greater satisfaction in face-to-face relationships for the wealthiest students, as opposed to the lower strata that have greater satisfaction in the relationships through the Internet. Finally, there was no relation among internet use, age and sex in the romantic relationships of the young people.El presente estudio centró su interés en identificar y evaluar los niveles de satisfacción en las relaciones de pareja generadas a través de internet. El objetivo fue evaluar si la variable uso de internet para generar una relación romántica, afectaba el grado de satisfacción en la relación para los jóvenes universitarios. Se aplicó un cuestionario de 20 ítems en un muestreo por conveniencia a 633 jóvenes universitarios, de quienes el 56% fueron mujeres y el 44% hombres; el rango de edad fue de 18 a 21 años, con validación por inclusión de 162 encuestas. El grado de satisfacción se evaluó mediante la escala de Hendrick y Hendrick (1992). El estudio evidencia que los jóvenes que han tenido relaciones románticas de manera presencial, en promedio mostraron estar significativamente más satisfechos (F= 58.78; Pr > F= 0.0001) que aquellos cuyas relaciones fueron generadas a través de internet. También evidencia, una interacción del uso del internet con el nivel socioeconómico, existe mayor satisfacción en estratos altos en relaciones de contexto presencial, contrario a los estratos bajos que tienen mayor satisfacción en las relaciones generadas mediante internet. Finalmente, no se encontró interacción entre uso de internet, edad y sexo en las relaciones románticas de los jóvenes

Increased dry-season length over southern Amazonia in recent decades and its implication for future climate projection

RESUMEN: We have observed that the dry-season length (DSL) has increased over southern Amazonia since 1979, primarily owing to a delay of its ending dates (dry-season end, DSE), and is accompanied by a prolonged fire season. A poleward shift of the subtropical jet over South America and an increase of local convective inhibition energy in austral winter (June–August) seem to cause the delay of the DSE in austral spring (September–November). These changes cannot be simply linked to the variability of the tropical Pacific and Atlantic Oceans. Although they show some resemblance to the effects of anthropogenic forcings reported in the literature, we cannot attribute them to this cause because of inadequate representation of these processes in the global climate models that were presented in the Intergovernmental Panel on Climate Change’s Fifth Assessment Report. These models significantly underestimate the variability of the DSE and DSL and their controlling processes. Such biases imply that the future change of the DSE and DSL may be underestimated by the climate projections provided by the Intergovernmental Panel on Climate Change’s Fifth Assessment Report models. Although it is not clear whether the observed increase of the DSL will continue in the future, were it to continue at half the rate of that observed, the long DSL and fire season that contributed to the 2005 drought would become the new norm by the late 21st century. The large uncertainty shown in this study highlights the need for a focused effort to better understand and simulate these changes over southern Amazonia

Toxoplasma gondii seropositivity associated to peri-urban living places in pregnant women in a rural area of Buenos Aires province, Argentina

Infection with Toxoplasma gondii is very common in humans throughout the world, the intake of raw or undercooked meat with tissue cysts and fruits, vegetables and water contaminated with parasite oocysts being the main routes of infection. Here, we analyzed the seroprevalence of anti-T. gondii antibodies in pregnant females (age 13–44 years; n = 920) between April 2014 and December 2017 from Chascomús (Argentina), a city immersed in a rural area. Altogether 320 tested positive for immunoglobulin G antibodies, yielding an overall seroprevalence of 34.8% (CI 95%: 31.7–37.9). No association was observed between seropositivity and age. In addition, by using the QGIS 3.2.1 software we analyzed the geographical distribution of 769 (83.6%) pregnant females in two main areas of the city: Urban (n = 157) and Peri-urban (n = 612) with a seroprevalence of 26.8% (CI 95%: 19.8–33.7) and 36.4% (CI 95%: 32.6–40.3) respectively, and this difference was statistically significant (p = 0.023). Furthermore, we assessed through a questionnaire survey, between April 2016 to December 2017, possible risk factors such as activity (urban and rural), home water supply, animal husbandry, presence of cats as pets, gardening and consumption of meat and its derivatives (pork, sheep meat and sausages) and their frequencies (consumption per week), not finding significant association with seropositivity. Significant differences was found when the seroprevalence was analyzed between the urban and peri-urban neighborhoods of the city of Chascomús. The higher seroprevalence in peri-urban neighborhoods could be due to an unfavorable socioeconomic situation and/or to undeveloped peri-urban environments, which is a risk factor that should be taken into account when planning the health care of pregnant females.Fil: Rivera, Elias Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Lavayén, Silvina N.. Dirección Nacional del Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr.C.G.Malbran". Instituto Nacional de Epidemiologia; ArgentinaFil: Sánchez, Paola. Hospital Municipal de Chascomus San Vicente de Paul; ArgentinaFil: Martins, Carlos M. A.. Hospital Municipal de Chascomus San Vicente de Paul; ArgentinaFil: Gómez, Etelvina. Hospital Municipal de Chascomus San Vicente de Paul; ArgentinaFil: Rodríguez, Jorge P.. Hospital Municipal de Chascomus San Vicente de Paul; ArgentinaFil: Arias, Marcela E.. Secretaría de Salud. Municipalidad de Chascomús; ArgentinaFil: Silva, Andrea Paula. Dirección Nacional del Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr.C.G.Malbran". Instituto Nacional de Epidemiologia; ArgentinaFil: Ángel, Sergio Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin

Reducing social vulnerability to environmental change : building trust through social collaboration on environmental monitoring

ABSTRACT: The occurrence of natural and socially driven catastrophic events has increased in the last few decades in response to global environmental changes. One of the most societally relevant challenges in managing the effects of these events is the establishment of risk management strategies that focus on managing vulnerability, particularly in disfavored countries, and communities among them. Most cases of enhanced vulnerability occur in, but are not limited to, developing countries, where the combination of social inequity, inappropriate use of natural resources, population displacement, and institutional mistrust, among other factors, make risk management particularly challenging. This paper presents a vulnerability-centered risk management framework based on social cohesion and integration principles that, combined with scientific, technical, and popular knowledge, lead to the development of social networks of risk reduction. This framework is intended as a strategy to strengthen early warning systems (EWS), where the human-related factor is among their most challenging components. Using water-related hazards as a case study, this paper describes the experience of the conformation of a social network for environmental monitoring using this model example on vulnerability reduction in the rural areas of the central Andes in Colombia. This experience allowed the effective conformation of a social network for environmental monitoring in 80 municipalities of Colombia, where communities developed a sense of ownership with the instrumentation and the network, strengthening links with local authorities and contributing to more efficient EWS. More generally, the authors highlight the need to develop vulnerability-centered risk management via community-building strategies, particularly for areas where little can be done to decrease the occurrence of catastrophic events