Evaluation of supervised classification methods for the estimation of spatiotemporal changes in the Merchán and Telecom paramos, Colombia

In recent years there has been significant progress in Geographic Information Systems (GIS) and the development of supervised classification methods, but until now these had not been used to accurately calculate the surface extent of paramos in sectors of the Eastern Cordillera of Colombia. Furthermore, these methods had not been used to estimate the distance between the boundaries of these moors and major geological features. For this reason, in the present research, five different supervised classification methods were evaluated, with the purpose of determining which of them has a higher resolution in order to reproduce the extension and surface distribution of the paramos of Merchán and Telecom in Saboyá, Boyacá, belonging to the Merchán - Iguaque complex in the Eastern Cordillera of Colombia. For this purpose, satellite images of the study area by Landsat 8 for the year 2018 were chosen and classified into some algorithms based on Machine Learning (SVM, RF, DT, BC and ANN). To establish the accuracy and reliability of the classification data of the terrain features, the Kappa Index was calculated, which allowed determining that the most accurate method for this case was Random Forest. In addition, since the boundaries of the moorlands coincide with geological structures or contacts between formations, the distance between the edge of the moorlands and these features was estimated. The results obtained in this research are considered as an important input for future multitemporal analysis as in landscape metrics, which serve as a tool for the development and decision making in the management of natural resources, biodiversity, provision of ecosystem services, as in the land use planning for the municipality of Saboyá-Boyacá.En los últimos años ha existido un avance significativo en los Sistemas de Información Geográfica (SIG) y en el desarrollo de métodos de clasificación supervisada, hasta ahora estos no habían sido utilizados para calcular con exactitud la extensión superficial de páramos en sectores de la Cordillera Oriental de Colombia y mucho menos para estimar la distancia entre los límites de esos páramos y los principales rasgos geológicos. Por esta razón, en la presente investigación se evaluaron cinco métodos de clasificación supervisada, con el propósito de determinar cuál de estos posee una mayor resolución para reproducir la extensión y distribución superficial de los páramos de Merchán y Telecom en Saboyá, Boyacá, pertenecientes al Complejo de Páramos Iguaque - Merchán en la Cordillera Oriental de Colombia. Con esta finalidad, se escogieron imágenes satelitales del área de estudio por medio de Landsat 8 para el año 2018 y se clasificaron utilizando algunos algoritmos basados en Machine Learning (SVM, RF, DT, BC y ANN). Para establecer la exactitud y confiabilidad de los datos de clasificación de las características del terreno se calculó el Índice Kappa, que permitió determinar que el método más preciso para este caso fue RF. Adicionalmente, dado que los límites de los páramos coinciden con estructuras geológicas o contactos entre formaciones, se estimó la distancia entre el borde de los páramos y esos rasgos. Los resultados obtenidos en esta investigación son considerados como insumo para futuros análisis multitemporales, y estimación de distintas sirven como herramienta para la elaboración y toma de decisiones en la gestión de recursos naturales, biodiversidad, prestación de servicios ecosistémicos, y ordenamiento territorial para el municipio de Saboyá-Boyacá

Modelo predictivo del índice de anisotropía del semicoque a partir de las propiedades de los carbones de la Cordillera Oriental de Colombia

This study developed a theoretical model for the determination of the Coke Anisotropy Quotient (CAQ) of semi-coke from the properties of its precursor coal. This is an useful parameter to define the resistance and reactivity of semi-coke in the blast furnace. For 36 semi-coke samples, a textural analysis was performed alongside a fluidity test to determine the real CAQ. The main textures observed were: isotropic and circular for high volatile bituminous coals (HVB); lenticular and fine ribbons for the medium volatile bituminous coals (MVB); and medium and thick ribbons for the low volatile bituminous coals (LVB). The CAQ varied in a range from 1 to 11. A principal component analysis (PCA) and multiple regression allowed to discriminated the importance of certain coal properties, in determining the CAQ to be recognized and to estimate parameters of the mathematical model. The statistical analysis suggested that CAQ can be best predicted from the fluidity, volatile matter, and Ro of the parent coals. The veracity of this model result was then tested using a second dataset from Poland. This work optimizes the usefulness of standard datasets in the prediction of CAQ's offering a means of quality control that could be implemented in Colombian coke production.En esta investigación se desarrolló un modelo teórico para la determinación del Cociente de Anisotropía del Coque (CAQ) del semicoque a partir de las propiedades de su carbón precursor. El CAQ permite definir la resistencia y la reactividad del semicoque en el alto horno. Usando material residual de las pruebas de fluidez se realizó un análisis textural para determinar el CAQ real sobre 36 muestras de semicoque. Las principales texturas observadas para los carbones bituminosos fueron: isotrópicas y circulares para los de alta volatilidad (HVB); cintas lenticulares y finas para los de media volatilidad (MVB); y cintas medias y gruesas para los de baja volatilidad (LVB). El CAQ varió en un rango de 1 a 11. Análisis de componentes principales (PCA) y regresión múltiple permitieron reconocer la importancia de ciertas propiedades del carbón para determinar el CAQ. El análisis estadístico sugirió que el CAQ puede predecirse mejor a partir de la fluidez,la materia volátil y el Ro de los carbones precursores. Este modelo fue validado a través de la comparación con datos reales de carbones de Polonia. Este trabajo proporciona un medio de control de calidad que podríaimplementarse en la producción de coque colombiano.&nbsp

MODELAMIENTO TERMOCINEMÁTICO 3D DE LA HISTORIA DE EXHUMACIÓN DEL SECTOR DE GUAYABETAL, KM 58 VÍA BOGOTÁ – VILLAVICENCIO: RELACIONES ENTRE CLIMA, RELIEVE Y TECTÓNICA

Las interacciones -clima-tectónica pueden dar lugar a cambios topográficos significativos tanto por aumentos en la elevación como por el incremento de pendientes. Estos cambios, en conjunción con la acción de la gravedad suscitan a su vez diferencias en la energía potencial de materiales geológicos (rocas, agua, etc.) desencadenando procesos geomórficos importantes tales como la erosión por agua, tanto laminar como concentrada, y los movimientos en masa En la vía Bogotá-Villavicencio en el kilómetro 58 del municipio de Guayabetal, se han presentado numerosos fenómenos de remoción en masa. La presente investigación explora como operan las interacciones entre el clima y la tectónica como procesos controladores del relieve actual a corto y largo plazo sobre la zona de estudio. Con esta finalidad se compilaron edades termocronológicas existentes en la zona, y se generó un modelo directo termocinemático 3D para estimar los pulsos y las tasas de exhumación. Los resultados de este último sugieren 3 pulsos de exhumación: el primero entre 40 Ma - 25 Ma a una tasa de exhumación de 0,5 km/Ma, seguido de un pulso entre 25 Ma - 15 Ma con una tasa de 0,1 km/Ma, y finalmente, desde 15 Ma al presente tasas de ~2 km/Ma. Adicionalmente, datos de precipitación fueron utilizados para estimar atributos primarios y secundarios del terreno, mientras que los datos de sismicidad instrumental fueron empleados para calcular la deformación sísmica, energía sísmica y levantamiento vertical por deformación sísmica. Las distintas variables fueron comparadas estadísticamente. Se concluye que el paisaje actual de la zona no es afectado uniformemente por la tectónica y las precipitaciones. En el noroccidente del área existen bajas tasas de erosión y actividad tectónica, así la evolución del paisaje es más pasiva, y el relieve es controlado por el patrón de precipitaciones. En contraste, hacia el suroriente específicamente entre macizo de Quetame y el piedemonte llanero, el relieve es controlado por la tectónica presente en el área. El efecto antrópico con las modificaciones al paisaje introducidas por la creación de una vía nacional, aunque es importante no fue analizado en la presente investigación

Prevalence and Predictors of Cerebral Microangiopathy Determined by Pulsatility Index in an Asymptomatic Population From the ILERVAS Project

Background: Little is known about the prevalence of cerebral microangiopathy (CM), which is related to cognitive impairment, in an asymptomatic population. Pulsatility index (PI) is an easily measurable parameter of cerebral vascular resistance in transcranial duplex of the middle cerebral artery (MCA) study. We aimed to determine the prevalence of CM measured by PI of MCA in low to moderate vascular risk subjects. Methods: We included 3,721 subjects between 45 and 70 years without previous history of vascular disease or diabetes mellitus and with at least one other vascular risk factor from the cross-sectional study ILERVAS (Lleida, Spain). Patients underwent transcranial duplex to determine MCA-PI. Possible CM was defined by MCA-PI >1.1. Carotid and femoral arteries ultrasound registration was done to determine the presence, the number, and the area of atheromatous plaques. Body mass index (BMI), pulse pressure (PP) and laboratory data were also recorded. Results: 439 (11.8%) subjects were excluded due to the low quality of transcranial duplex images. Median age was 57 [IQR 52, 62] years. Possible CM was found in 424 (12.9%) subjects. CM patients had higher prevalence of plaques than non-CM (77.4 vs. 66.4%, p < 0.001). PI showed a positive linear correlation with the number of territories with plaques (r = 0.130, p < 0.001), and the total plaque area (r = 0.082, p < 0.001). The predictors of possible CM were the age, male gender, and PP. Conclusions: In low-to-moderate vascular risk asymptomatic population, the proportion of abnormal brain microvascular bed determined by MCA-PI is not negligible. The planned 10-year follow-up will describe the clinical relevance of these findings.This work was supported by grants from the Diputacio de Lleida, Instituto de Salud Carlos III (RETIC RD16/0009/0011) and Ministerio de Ciencia, Inovación y Universidades (IJC2018-037792-I). FP was supported by the Catalan Autonomous Government’s Agència de Gestió d’Ajuts Universitaris i de Recerca (2017 suport a les activitats dels grups de recerca 1628). RP was supported by the Spanish Ministry of Science, Innovation, and Universities (grant RTI2018-099200-B-I00), and the Generalitat of Catalonia: Agency for Management of University and Research Grants (2017SGR696). This study was co-financed by FEDER funds from the European Union (A way to build Europe). IRBLleida is a CERCA Programme/Generalitat of Catalonia

Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat

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

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

Search for Physics beyond the Standard Model in Events with Overlapping Photons and Jets

Results are reported from a search for new particles that decay into a photon and two gluons, in events with jets. Novel jet substructure techniques are developed that allow photons to be identified in an environment densely populated with hadrons. The analyzed proton-proton collision data were collected by the CMS experiment at the LHC, in 2016 at root s = 13 TeV, and correspond to an integrated luminosity of 35.9 fb(-1). The spectra of total transverse hadronic energy of candidate events are examined for deviations from the standard model predictions. No statistically significant excess is observed over the expected background. The first cross section limits on new physics processes resulting in such events are set. The results are interpreted as upper limits on the rate of gluino pair production, utilizing a simplified stealth supersymmetry model. The excluded gluino masses extend up to 1.7 TeV, for a neutralino mass of 200 GeV and exceed previous mass constraints set by analyses targeting events with isolated photons.Peer reviewe

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| &lt; 0.03 at 95% confidence level. [Figure not available: see fulltext.