Propuesta metodológica para el manejo de acuíferos costeros el problema de la intrusión salina

Se espera que el crecimiento económico y poblacional en zonas costeras y el cambio global, aumenten la presión sobre el recurso hídrico principalmente por el tipo de actividades confrontadas. Las herramientas de modelación para abordar cuantitativamente las cantidades de agua disponibles facilitaran a los grupos interesados proyectar los planes de ordenamiento y manejo correctos que permitan equilibrar desarrollos económicos y poblacionales a la par con la sostenibilidad y disponibilidad del recurso. La definición de escenarios que permitan explorar las posibles condiciones de futuros desconocidos y plantear tanto a nivel físico como socioeconómico un espectro de posibles situaciones que permitan a técnicos y decisores considerar las implicaciones del cambio climático sobre el recurso hidrogeológico respecto a las situación actual, es una manera eficiente de conectar las herramientas de modelación con las futuras políticas de gestión y planificación del agua subterránea en zonas costeras. Como parte aplicativa dentro de la tesis, se estudia la sensibilidad de los parámetros que determinan la intrusión salina en acuíferos costeros: conductividad hidráulica, dispersión, bombeo, recarga y nivel del mar. Se evalúa el impacto del cambio climático en cantidad y calidad: variaciones en la recarga del acuífero, e intensificación del fenómeno intrusión salina. Se construyo un modelo hipotético consistente en una caja rectangular de 1000mx10000mx20m donde una de sus fronteras representa la interfase mar-acuífero, y se elaboraron un conjunto de simulaciones separadas para analizar cada parámetro mencionado en el programa SEAWAT-2000. Las simulaciones se realizan bajo diferentes escenarios, partiendo de un estado permanente o natural, para comparar más claramente las consecuencias de un escenario de cambio climático y explotación intensa. Los resultados muestran que el ascenso del nivel del mar causa una intrusión salina más aguda y que ligado con un bombeo intenso pueden estresar fuertemente al acuífero. / Abstract. It is expected that economic growth and population in coastal areas and global change, may increase the exploitation of water resources mainly by conflicting activities. The modeling tools to address quantitatively the amount of available water will provide interested groups to project management plans that balance economic development and population simultaneously with the availability and sustainability of the resource. The definition of scenarios to explore possible future unknown conditions in order to raise both a physical and socio-economic spectrum of possible situations that allow technicians and decision makers to consider the climate change implications regarding the hydrogeological situation, is an efficient way to connect with the modeling tools for future policy planning and groundwater management in coastal areas. The sensitivity of the parameters that determine the saline intrusion in coastal aquifers: hydraulic conductivity, dispersion, pumping, recharge and sea level, is studied in this work. The impact of climate change in quantity and quality variations in the aquifer recharge, and intensification of the phenomenon saline intrusion, is assessed. A hypothetical model consisting of a rectangular 1000mx10000mx20m box where one of its borders represents the aquifer-ocean interface, was constructed. Different simulations to analyze each one of the mentioned parameters were carried out by means of the software SEAWAT-2000. The simulations were performed under different scenarios, based on a permanent or natural state, to compare clearly the consequences of a climate change scenario and intensive farming. The results show that sea level rise causes an acute saline intrusion and associated with an intense pumping can severely stress the aquifer.Maestrí

Propuesta metodológica para el manejo de acuíferos costeros el problema de la intrusión salina

Se espera que el crecimiento económico y poblacional en zonas costeras y el cambio global, aumenten la presión sobre el recurso hídrico principalmente por el tipo de actividades confrontadas. Las herramientas de modelación para abordar cuantitativamente las cantidades de agua disponibles facilitaran a los grupos interesados proyectar los planes de ordenamiento y manejo correctos que permitan equilibrar desarrollos económicos y poblacionales a la par con la sostenibilidad y disponibilidad del recurso. La definición de escenarios que permitan explorar las posibles condiciones de futuros desconocidos y plantear tanto a nivel físico como socioeconómico un espectro de posibles situaciones que permitan a técnicos y decisores considerar las implicaciones del cambio climático sobre el recurso hidrogeológico respecto a las situación actual, es una manera eficiente de conectar las herramientas de modelación con las futuras políticas de gestión y planificación del agua subterránea en zonas costeras. Como parte aplicativa dentro de la tesis, se estudia la sensibilidad de los parámetros que determinan la intrusión salina en acuíferos costeros: conductividad hidráulica, dispersión, bombeo, recarga y nivel del mar. Se evalúa el impacto del cambio climático en cantidad y calidad: variaciones en la recarga del acuífero, e intensificación del fenómeno intrusión salina. Se construyo un modelo hipotético consistente en una caja rectangular de 1000mx10000mx20m donde una de sus fronteras representa la interfase mar-acuífero, y se elaboraron un conjunto de simulaciones separadas para analizar cada parámetro mencionado en el programa SEAWAT-2000. Las simulaciones se realizan bajo diferentes escenarios, partiendo de un estado permanente o natural, para comparar más claramente las consecuencias de un escenario de cambio climático y explotación intensa. Los resultados muestran que el ascenso del nivel del mar causa una intrusión salina más aguda y que ligado con un bombeo intenso pueden estresar fuertemente al acuífero. / Abstract. It is expected that economic growth and population in coastal areas and global change, may increase the exploitation of water resources mainly by conflicting activities. The modeling tools to address quantitatively the amount of available water will provide interested groups to project management plans that balance economic development and population simultaneously with the availability and sustainability of the resource. The definition of scenarios to explore possible future unknown conditions in order to raise both a physical and socio-economic spectrum of possible situations that allow technicians and decision makers to consider the climate change implications regarding the hydrogeological situation, is an efficient way to connect with the modeling tools for future policy planning and groundwater management in coastal areas. The sensitivity of the parameters that determine the saline intrusion in coastal aquifers: hydraulic conductivity, dispersion, pumping, recharge and sea level, is studied in this work. The impact of climate change in quantity and quality variations in the aquifer recharge, and intensification of the phenomenon saline intrusion, is assessed. A hypothetical model consisting of a rectangular 1000mx10000mx20m box where one of its borders represents the aquifer-ocean interface, was constructed. Different simulations to analyze each one of the mentioned parameters were carried out by means of the software SEAWAT-2000. The simulations were performed under different scenarios, based on a permanent or natural state, to compare clearly the consequences of a climate change scenario and intensive farming. The results show that sea level rise causes an acute saline intrusion and associated with an intense pumping can severely stress the aquifer.Maestrí

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

Peer reviewe

Measurement of the Higgs boson production rate in association with top quarks in final states with electrons, muons, and hadronically decaying tau leptons at s√=13TeV

The rate for Higgs (H) bosons production in association with either one (tH) or two (tt¯H) top quarks is measured in final states containing multiple electrons, muons, or tau leptons decaying to hadrons and a neutrino, using proton–proton collisions recorded at a center-of-mass energy of 13TeV by the CMS experiment. The analyzed data correspond to an integrated luminosity of 137fb−1. The analysis is aimed at events that contain H→WW, H→ττ, or H→ZZ decays and each of the top quark(s) decays either to lepton+jets or all-jet channels. Sensitivity to signal is maximized by including ten signatures in the analysis, depending on the lepton multiplicity. The separation among tH, tt¯H, and the backgrounds is enhanced through machine-learning techniques and matrix-element methods. The measured production rates for the tt¯H and tH signals correspond to 0.92±0.19(stat)+0.17−0.13(syst) and 5.7±2.7(stat)±3.0(syst) of their respective standard model (SM) expectations. The corresponding observed (expected) significance amounts to 4.7 (5.2) standard deviations for tt¯H, and to 1.4 (0.3) for tH production. Assuming that the Higgs boson coupling to the tau lepton is equal in strength to its expectation in the SM, the coupling yt of the Higgs boson to the top quark divided by its SM expectation, κt=yt/ySMt, is constrained to be within −0.9<κt<−0.7 or 0.7<κt<1.1, at 95% confidence level. This result is the most sensitive measurement of the tt¯H production rate to date.SCOAP

Interacciones suelo-atmósfera en Suramérica tropical y Colombia en múltiples escalas de tempo

In this thesis, we have studied diverse land-atmosphere interactions (LAI) in Tropical South America (TropSA) and Colombia at several timescales. First, we evaluated the specific role of LAI during the 2009-2011 extreme ENSO phases at continental scale. In particular, we developed a simplified model of LAI on TropSA using graph theory based on linear and non-linear metrics at interannual timescales. Over a specific region of the Central Andes of Colombia (CAC), we explored the seasonal variability of the diurnal cycle of rainfall. A moisture recycling model was implemented to provide evidence supporting the key role of LAI in this variability. The results of the thesis indicate that the strength of land-atmosphere processes in TropSA is influenced by ENSO and depends on the availability of water and energy in soil layers. Soil moisture plays a relevant role at the interannual scale in the coupling between temperature and rainfall through ENSO in this region. The structural model of links developed under the influence of ENSO establishes that surface temperature is a key variable in diagnosing the dynamics of the LAI in TropSA. On shorter space scales, moisture recycling contributes to the understanding of the seasonal dynamics of moisture sources explaining the shifting phase of the diurnal cycle of rainfall through the year over the CAC. The thesis highlights the active role of LAI in the hydroclimatic dynamics of the explored spatiotemporal contexts and the importance to continue improving our understanding of these mechanisms. (Tomado de la fuente)En esta tesis se han estudiado las interacciones tierra-atmósfera (ITA) sobre Suramérica Tropical (SATrop) y Colombia en múltiples escalas temporales. Evaluamos el papel específico de las ITA durante las fases extremas del ENSO 2009-2011 a escala continental en SATrop y Colombia. Asimismo, desarrollamos un modelo simplificado de las ITA sobre SATrop usando teoría de grafos basado en métricas lineales y no lineales a escala de tiempo interanual. A escala local, exploramos la variabilidad estacional del ciclo diurno de la lluvia en una región específica de los Andes Centrales de Colombia (ACC), e implementamos un modelo de reciclaje de humedad para encontrar evidencias que soporten nuestra hipótesis del papel de las ITA en este contexto. Los resultados de la tesis indican que la potencia de los procesos tierra-atmósfera sobre SATrop está influenciada por ENSO y depende de la disponibilidad de agua y energía en las capas del suelo. La humedad en el suelo tiene un papel relevante a nivel interanual en el acoplamiento entre temperatura y lluvia a través de ENSO en esta región. El modelo estructural de enlaces que se construyó bajo la influencia de ENSO establece que la temperatura superficial es una variable clave para diagnosticar la dinámica de las ITA en SATrop. En la región de estudio sobre los ACC, encontramos que el ciclo diurno es predominantemente unimodal durante todo el año, pero su fase cambia con la fase del ciclo anual. El reciclaje de humedad, como una expresión de las ITA, aporta a la comprensión de la dinámica estacional de este ciclo diurno promedio de lluvia en los ACC. En síntesis, la tesis determinó el papel activo de las ITA en la dinámica hidroclimática de los contextos espacio-temporales explorados y la necesidad de seguir mejorando nuestro entendimiento de estos mecanismos. (Tomado de la fuente)Línea de investigación: HidroclimatologíaDoctoradoTesis de Doctor en Ingeniería - Recursos Hidráulico

Aplicación de la distribución generalizada de Pareto para la detección de colas pesadas en series de caudales máximos en ríos del Amazonas y de la Zona Andina Colombiana

Se determinó la existencia o no de colas pesadas en las funciones de distribución de probabilidad (fdp) de caudales máximos de algunos ríos ubicados en la selva Amzónica y la Zona Andina de Colombia y, dado el caso, se estimaron los parámetros asociados a estas distribuciones por medio de la Distribucion Generalizada de Pareto

New Insights on Land Surface-Atmosphere Feedbacks over Tropical South America at Interannual Timescales

We present a simplified overview of land-atmosphere feedbacks at interannual timescales over tropical South America as structural sets of linkages among surface air temperature (T), specific humidity at 925 hPa (q925), volumetric soil water content (&Theta;), precipitation (P), and evaporation (E), at monthly scale during 1979&ndash;2010. Applying a Maximum Covariance Analysis (MCA), we identify the modes of greatest interannual covariability in the datasets. Time series extracted from the MCAs were used to quantify linear and non-linear metrics at up to six-month lags to establish connections among variables. All sets of metrics were summarized as graphs (Graph Theory) grouped according to their highest ENSO-degree association. The core of ENSO-activated interactions is located in the Amazon River basin and in the Magdalena-Cauca River basin in Colombia. Within the identified multivariate structure, &Theta; enhances the interannual connectivity since it often exhibits two-way feedbacks with the whole set of variables. That is, &Theta; is a key variable in defining the spatiotemporal patterns of P and E at interannual time-scales. For both the simultaneous and lagged analysis, T activates non-linear associations with q925 and &Theta;. Under the ENSO influence, T is a key variable to diagnose the dynamics of interannual feedbacks of the lower troposphere and soil interfaces over tropical South America. ENSO increases the interannual connectivity and memory of the feedback mechanisms

Modelo numérico del acuífero de la isla de San Andrés, Colombia.

Se utilizó el modulo SEAWAT 4.0 (Langevin et al., 2003) para construir un modelo numérico del acuífero de la Isla que involucrara la interfase agua dulce agua salada. Para la calibración en estado transitorio del modelo numérico se utilizó la información de niveles en los pozos de la cuenca del Cove, la zona más productiva ubicada en el centro de la Isla, en el período 2007-2008, y se determinaron 2 periodos de estrés por año: uno correspondiente al modo frío y otro al modo cálido

Traffic and Industrial Contributions of Particle-Bound PAHs during an Air Pollution Event in the Metropolitan Area of Medellin-Colombia: Inhalation Intake Risk during Pregnancy

Air pollution includes particle-bound polycyclic aromatic hydrocarbons (PAHs), which eventually reach the placenta, triggering adverse perinatal outcomes through long-term exposure. Lately, air pollution has increased over the Metropolitan Area of Medellin-Colombia (MAMC), but its effects on pregnancy are still unknown. In this research, a real-time analysis of total airborne PAHs was made using a photoelectric sensor for residential places influenced by the industrial and traffic sources affecting the southern and northern MAMC during the second peak of the bimodal tendency for PM2.5 emissions in this region. Additionally, individual PAHs were analyzed by GC/MS coupled with pressurized hot water extraction methodology. The data were applied using an inhalation intake model to assess pregnancy exposure. The average concentration of PAHs in the southern MAMC was three times higher than in the northern MAMC, where the missed abortion rate has been 1.4 times higher according to the database. Previous research indicates that PAHs act as endocrine-disrupting chemicals (EDCs) during pregnancy and that even heavy congeners could reside in umbilical cord blood. Finally, the annual series of missed abortion rates in the MAMC exhibited a significant correlation with the annual average levels of PM2.5, which were associated with PAHs through correlation analysis (r2 = 0.69, p < 0.01). While this significant correlation does not imply causality, our results suggest an important connection between both variables, opening a gap for a deeper understanding of how regions with high PAH convergence influence the missed abortion rates in MAMC