Overview of the vector-like quark searches with the LHC data collected by the ATLAS detector

In 2012 the discovery of the Higgs boson by the ATLAS and CMS collaborations set a milestone in particle physics by finding the missing piece of the Standard Model. Nonetheless some questions are still open: the origin of the mass of the neutrino and finding the missing candidate for dark matter are some examples. One of the main issues with the Standard Model is the hierarchy problem which appears when trying to go to high energy scales at which the theory cannot accommodate corrections large enough to explain the observed nature. Vector-like quarks appear naturally in some non-supersymmetric models which try to find a solution for this issue. The different searches for vector-like quarks within the ATLAS Collaboration using data collected at a centre-of-mass energy of 8 and 13~TeV with integrated luminosities of $20.3\rm{~fb^{-1}}$ (8~TeV) and $3.2\rm{~fb^{-1}}$ and $14.7\rm{~fb^{-1}}$ (13~TeV) are discussed.Comment: $9^{th}$ International Workshop on Top Quark Physics Olomouc, Czech Republic, September 19--23, 201

Searches for flavour changing neutral currents in the top sector

Flavour Changing Neutral Current (FCNC) processes are forbidden at tree level in the Standard Model and highly suppressed at higher orders. This makes FCNC one of the key processes to search for new physics since any small deviations from the Standard Model expectations could have a big impact. Both ATLAS and CMS Collaborations have designed a comprehensive strategy to search for FCNC in top quark physics both in the production and decay. The strategies followed by both collaborations are here described, using data from $pp$ collisions at the LHC collected at a centre of mass energies of 7 and 8~TeV with integrated luminosities ranging from $5~\rm{fb}^{-1}$ to $20.3~\rm{fb}^{-1}$.Comment: Proceedings for the 9th International Workshop on Top Quark Physics Olomouc, Czech Republic, September 19--23, 201

Analysis of air flow past and through the 2415-3S airfoil for an unmanned aerial vehicle with internal propulsion system

This paper deals with the prediction of velocity fields on the 2415-3S airfoil which will be used for an unmanned aerial vehicle with internal propulsion system and in this way analyze the air flow through an internal duct of the airfoil using computational fluid dynamics. The main objective is to evaluate the effect of the internal air flow past the airfoil and how this affects the aerodynamic performance by means of lift and drag forces. For this purpose, three different designs of the internal duct were studied; starting from the base 2415-3S airfoil developed in previous investigation, basing on the hypothesis of decreasing the flow separation produced when the propulsive airflow merges the external flow, and in this way obtaining the best configuration. For that purpose, an exhaustive study of the mesh sensitivity was performed. It was used a non-structured mesh since the computational domain is three-dimensional and complex. The selected mesh contains approximately 12.5 million elements. Both the computational domain and the numerical solution were made with commercial CAD and CFD software, respectively. Air, incompressible and steady was analyzed. The boundary conditions are in concordance with experimental setup in the AF 6109 wind tunnel. The k-e model is utilized to describe the turbulent flow process as followed in references. Results allowed obtaining velocity contours as well as lift and drag coefficients and also the location of separation and reattachment regions in some cases for zero degrees of angle of attack on the internal and external surfaces of the airfoil. Finally, the selection of the configuration with the best aerodynamic performance was made, selecting the option without curved baffles

Numerical analysis of air flow past the 2415-3S airfoil for an unmanned aerial vehicle with internal propulsion system

This paper deals with the prediction of pressure and velocity fields on the 2415-3S airfoil which will be used for and unmanned aerial vehicle with internal propulsion system and in this way analyze the air flow through an internal duct of the airfoil using computational fluid dynamics. The main objective is to evaluate the effect of the internal air flow past the airfoil and how this affects the aerodynamic performance by means of lift and drag forces. For this purpose, three different designs of the internal duct were studied; starting from the base 2415-3S airfoil developed in previous investigation, basing on the hypothesis of decreasing the flow separation produced when the propulsive airflow merges the external flow, and in this way obtaining the best configuration. For that purpose, an exhaustive study of the mesh sensitivity was performed. It was used a non-structured mesh since the computational domain is tridimensional and complex. The selected mesh contains approximately 12.5 million elements. Both the computational domain and the numerical solution were made with commercial CAD and CFD software respectively. Air, incompressible and steady was analyzed. The boundary conditions are in concordance with experimental setup in the AF 6109 wind tunnel. The k-ε model is utilized to describe the turbulent flow process as followed in references. Results allowed obtaining pressure and velocity contours as well as lift and drag coefficients and also the location of separation and reattachment regions in some cases for zero degrees of angle of attack on the internal and external surfaces of the airfoil. Finally, the selection of the configuration with the best aerodynamic performance was made, selecting the option without curved baffles

Fertilización de maíz (Zea mays L.) en suelos volcánicos de Nariño, Colombia.

Se efectuaron ensayos de fertilización en suelos nariñenses de clima frío, frío moderado y medio, para determinar las dosis más adecuados de nutrimentos para maíces mejorados. Los lotes en la zona fría se escogieron en suelos nuevos, que antes habían estado en pastos y en suelos previamente cultivados con papa; presentaban topografía moderadamente inclinada y diferentes grados de erosión. Los lotes en clima medio estaban previamente cultivados con papa, presentando topografía inclinada y erosión severa. Se fertilizó con distintas dosis de N, P, K, Ca, Mg, y Agrimins (producto comercial consistente en una mezcla de elementos menores). Los rendimientos en la primera y segunda cosecha de maíz en suelos de clima frío sin erosión cultivados con papa o pastos previamente, fueron altos aún sin la aplicación de fertilizantes. En suelos de pendiente inclinada fuertemente erosionados, los rendimientos aumentaron al aplicar N y P en dosis de 50 a 100 kg/ha de N y P2O5, además de 30-60 kg/ha de K2O. En suelos de clima frío moderano hubo respuesta del cultivo con la aplicación de 50-100 kg/ha de N, hasta 120 kg/ha de P2O5 y 100-200 kg/ha de cal agrícla; además se recomienda aplicar 30-50 kg/ha de K2O. En suelos de clima medio, inclinados y fuertemente erosionados se recomienda aplicar N fraccionado (la tercera parte o la mitad al momento de la siembra y el resto cuando la planta tenga 75-100 cm de altura). El P2O5 y el K2O se pueden aplicar en dosis máximas de 50 kg/ha. En estos suelos, el Agrimins, el sulfato de magnesio y la cal agrícola tuvieron poco efecto en la producción de maízMaíz-Zea may

Respuesta del plátano (Musa sp. grupo AAB), variedad Dominico, a la fertilización en suelos de clima medio en Antioquia.

En suelos Dystrandept y Dystropept, de texturas medias, muy fuertemente ácidos (pH 4.9-5.6), medios a altos en materia orgánica (3.2-14.9 por ciento), bajos en P (menor que 9.9 ppm-Bray II), bajos en las bases intercambiables Mg (menor que 0.4 meq/100 g) y K (menor que 0.17 meq/100 g) y bajos medios en Ca (menor que 1.6 meq/100 g), el plátano Dominico (Musa spp., grupo AAB), en cada una de las cosechas sucesivas realizadas por cepa, mostró diferencias altamente significativas (P igual a 0.01) entre tratamientos que recibieron diferentes dosis de fertilizantes. De los nutrimentos estudiados, el P fue el más limitante de la producción, ya que la dosis más baja aplicada, 4 kg de oxido fosfórico, produjo racimos pequeños (12.7 kg), con el menor número de manos por racimo (6) y peso de los plátanos (159 g) en la primera mano, además, las plantas tuvieron un desarrollo reducido con altura media de 2.8 m, 15,5 cm de diámetro en el pseudotallo a 1 m de la base, y apenas 7 hojas aparentemente sanas al momento de la inflorescencia. Hubo efecto similar, aunque no tan drástico, con la dosis más baja de K, 16 kg de oxido de potasio, en cambio, la dosis mínima de N, 8 kg/ha, no tuvo efecto adverso en la producción ni en el desarrollo del cultivo. Al analizar en conjunto los datos del experimento se concluyó que para estos suelos y similares se necesita un fertilizante comercial grado 0.5:1:3 entre N: oxido fosfórico: oxido de potasio, en dosis de 350 a 450 kg/ha cada año, para obtener producciones altas, de más de 17 t/ha, y racimos de buena calidad. Cuando al N, P y K se adicionó Mg y S, se mejoró sustancialmente la producción y calidad del racim

Radiation and Scattering of EM Waves in Large Plasmas Around Objects in Hypersonic Flight

Hypersonic flight regime is conventionally defined for Mach> 5; in these conditions, the flying object becomes enveloped in a plasma. This plasma is densest in thin surface layers, but in typical situations of interest it impacts electromagnetic wave propagation in an electrically large volume. We address this problem with a hybrid approach. We employ Equivalence Theorem to separate the inhomogeneous plasma region from the surrounding free space via an equivalent (Huygens) surface, and the Eikonal approximation to Maxwell equations in the large inhomogeneous region for obtaining equivalent currents on the separating surface. Then, we obtain the scattered field via (exact) free space radiation of these surface equivalent currents. The method is extensively tested against reference results and then applied to a real-life re-entry vehicle with full 3D plasma computed via Computational Fluid Dynamic (CFD) simulations. We address both scattering (RCS) from the entire vehicle and radiation from the on-board antennas. From our results, significant radio link path losses can be associated with plasma spatial variations (gradients) and collisional losses, to an extent that matches well the usually perceived blackout in crossing layers in cutoff. Furthermore, we find good agreement with existing literature concerning significant alterations of the radar response (RCS) due to the plasma envelope

Radiation and Scattering of EM Waves in Large Plasmas Around Objects in Hypersonic Flight

Hypersonic flight regime is conventionally defined for Mach larger than 5; in these conditions, the flying object becomes enveloped in a plasma. This plasma is densest in thin surface layers, but in typical situations of interest it impacts electromagnetic wave propagation in an electrically large volume. We address this problem with a hybrid approach. We employ Equivalence Theorem to separate the inhomogeneous plasma region from the surrounding free space via an equivalent (Huygens) surface, and the Eikonal approximation to Maxwell equations in the large inhomogeneous region for obtaining equivalent currents on the separating surface. Then, we obtain the scattered field via (exact) free space radiation of these surface equivalent currents. The method is extensively tested against reference results and then applied to a real-life re-entry vehicle with full 3D plasma computed via Computational Fluid Dynamic (CFD) simulations. We address both scattering (RCS) from the entire vehicle and radiation from the on-board antennas. From our results, significant radio link path losses can be associated with plasma spatial variations (gradients) and collisional losses, to an extent that matches well the usually perceived blackout in crossing layers in cutoff. Furthermore, we find good agreement with existing literature concerning significant alterations of the radar response (RCS) due to the plasma envelope