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

Dual-path state reconstruction scheme for propagating quantum microwaves and detector noise tomography

Quantum state reconstruction involves measurement devices that are usually described by idealized models, but not known in full detail in experiments. For weak propagating microwaves, the detection process requires linear amplifiers which obscure the signal with random noise. Here, we introduce a theory which nevertheless allows one to use these devices for measuring all quadrature moments of propagating quantum microwaves based on cross-correlations from a dual-path amplification setup. Simultaneously, the detector noise properties are determined, allowing for tomography. We demonstrate the feasibility of our novel concept by proof-of-principle experiments with classical mixtures of weak coherent microwaves.Comment: 11 pages, 3 figure

Influencia de la expectativa sobre la orientación de la atención

Primeres Jornades de Foment de la Investigació de la FCHS (Any 1995-1996

Role of the Fractalkine Receptor in CNS Autoimmune Inflammation: New Approach Utilizing a Mouse Model Expressing the Human CX3CR1

Multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS) is the leading cause of non-traumatic neurological disability in young adults. Immune mediated destruction of myelin and oligodendrocytes is considered the primary pathology of MS, but progressive axonal loss is the major cause of neurological disability. In an effort to understand microglia function during CNS inflammation, our laboratory focuses on the fractalkine/CX3CR1 signaling as a regulator of microglia neurotoxicity in various models of neurodegeneration. Fractalkine (FKN) is a transmembrane chemokine expressed in the CNS by neurons and signals through its unique receptor CX3CR1 present in microglia. During experimental autoimmune encephalomyelitis (EAE), CX3CR1 deficiency confers exacerbated disease defined by severe inflammation and neuronal loss. The CX3CR1 human polymorphism I249/M280 present in ∼20% of the population exhibits reduced adhesion for FKN conferring defective signaling whose role in microglia function and influence on neurons during MS remains unsolved. The aim of this study is to assess the effect of weaker signaling through hCX3CR1I249/M280 during EAE. We hypothesize that dysregulated microglial responses due to impaired CX3CR1 signaling enhance neuronal/axonal damage. We generated an animal model replacing the mouse CX3CR1 locus for the hCX3CR1I249/M280 variant. Upon EAE induction, these mice exhibited exacerbated EAE correlating with severe inflammation and neuronal loss. We also observed that mice with aberrant CX3CR1 signaling are unable to produce FKN and ciliary neurotrophic factor during EAE in contrast to wild type mice. Our results provide validation of defective function of the hCX3CR1I249/M280 variant and the foundation to broaden the understanding of microglia dysfunction during neuroinflammation. © 2018 Cardona et al

Fertilización de la papa (Solanum tuberosum L.) en los suelos andosoles del Departamento de Nariño, Colombia.

Se determinaron las dosis más adecuadas de N, P, K y cal agrícola en cultivos de papa de diferentes zonas productoras de Nariño. Entre los años 1953 y 1970 se establecieron pruebas regionales en fincas de agricultores y ensayos básicos en la Granja Obonuco. Las características físicas de los suelos donde se sembraron estos ensayos son muy favorables para el cultivo de la papa, en cambio, las propiedades químicas limitan considerablemente los rendimientos, en especial las deficiencias de N y P. Los resultados de los diferentes ensayos indican la necesidad de aplicaciones conjuntas de N y P en dosis que dependen del contenido de materia orgánica y del P aprovechable cuando se determina por Bray II, así, para suelos con menos de 10 por ciento de materia orgánica y 30 ppm de P, se debe aplicar 100-200 kg/ha de N en presencia de 300-400 kg/ha de P2O5 y en suelos con contenidos mayores de materia orgánica y P, las aplicaciones se reducen a 50-100 kg/ha de N más 100-200 kg/ha de P2O5. Con relación al K, en el suelo existen cantidades suficientes de este elemento, sin embargo, debido a la alta capacidad de lixiviación del P asequible de los suelos, se debe aplicar, junto con N y P hasta 50 kg/ha de K2O, en cada cosecha, para evitar un agotamiento de este elemento. Debido a que estos suelos son ricos en Ca intercambiable, la probabilidad de respuesta al encalamiento es muy reducidaPapa-Solanum tuberosu

Electromyography: A Simple and Accessible Tool to Assess Physical Performance and Health during Hypoxia Training. A Systematic Review

Producción CientíficaHypoxia causes reduced partial pressure of oxygen in arterial blood and induces adaptations in skeletal muscle that may affect individuals’ physical performance and muscular health. These muscular changes are detectable and quantifiable by electromyography (EMG), an instrument that assesses electrical activity during active contraction at rest. EMG is a relatively simple and accessible technique for all patients, one that can show the degree of the sensory and motor functions because it provides information about the status of the peripheral nerves and muscles. The main goal of this review is to evaluate the scientific evidence of EMG as an instrument for monitoring different responses of skeletal muscles subjected to external stimuli such as hypoxia and physical activity. A structured search was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in Medline/PubMed, Scielo, Google Scholar, Web of Science, and Cochrane Library Plus. The search included articles published in the last 25 years until May 2020 and was restricted to English- and Spanish-language publications. As such, investigators identified nine articles that met the search criteria. The results determined that EMG was able to detect muscle fatigue from changes in the frequency spectrum. When a muscle was fatigued, high frequency components decreased and low frequency components increased. In other studies, EMG determined muscle activation increased during exercise by recruiting motor units and by increasing the intensity of muscle contractions. Finally, it was also possible to calculate the mean quadriceps quadratic activity used to obtain an image of muscle activation. In conclusion, EMG offers a suitable tool for monitoring the different skeletal muscle responses and has sufficient sensitivity to detect hypoxia-induced muscle changes produced by hypoxic stimuli. Moreover, EMG enhances an extension of physical examination and tests motor-system integrity

Angular distributions in tt¯H(H→bb¯) reconstructed events at the LHC

The associated production of a Higgs boson and a top-quark pair, tt¯H, in proton-proton collisions is addressed in this paper for a center of mass energy of 13TeV at the LHC. Dileptonic final states of tt¯H events with two oppositely charged leptons and four jets from the decays t→bW+→bℓ+νℓ, t¯→b¯W−→b¯ℓ−ν¯ℓ and h→bb¯, are used. Signal events, generated with MadGraph5_aMC@NLO, are fully reconstructed by applying a kinematic fit. New angular distributions of the decay products as well as angular asymmetries are explored in order to improve discrimination of tt¯H signal events over the dominant irreducible background contribution, tt¯bb¯. Even after the full kinematic fit reconstruction of the events, the proposed angular distributions and asymmetries are still quite different in the tt¯H signal and the dominant background (tt¯bb¯).This work was partially supported by Fundação para a Ciência e Tecnologia, FCT (projects CERN/FP/123619/2011 and EXPL/FIS-NUC/1705/2013, grants SFRH/BI/52524/2014 and SFRH/BD/73438/2010, and contracts IF/00050/2013 and IF/00014/2012). The work of M.C.N. Fiolhais was supported by LIP-Laboratório de Instrumentação e Física Experimental de Partículas, Portugal (grant PestIC/FIS/LA007/2013). The work of R.S. is supported in part by FCT under contract PTDC/FIS/117951/2010. Special thanks go to Juan Antonio Aguilar-Saavedra for all the fruitful discussions and a long term collaboration

Respuesta de la cebada (Hordeum vulgare) a diferentes dosis de fertilizantes en suelos influenciados por cenizas volcánicas en Nariño.

Entre 1956 y 1968 se establecieron 12 pruebas de fertilización en cebada en suelos influenciados por deposiciones de cenizas volcánicas, en el Departamento de Nariño. Estos experimentos se efectuaron con el propósito de establecer las dosis y combinaciones de N, P, K y más adecuadas para cebada. Se usaron las variedades mejoradas Funza y Galeras, con una densidad de siembra que osciló entre 60 y 80 kg/ha de semilla. Los resultados de los análisis de suelos indican en promedio, suelos fuertemente ácidos (pH 5.5), altos en materia orgánica (M.O. 12.4 por ciento) en K intercambiable (0.73 meq/100 gr de suelo) y con un contenido muy variable en P aprovechable que oscila entre 8.5 y 37.6 ppm con un promedio de 22.6 ppm de P (Bray II). De acuerdo a los resultados de campo, las aplicaciones más aconsejables de los diferentes nutrimentos varían entre 30 y 60 kg/ha de N en combinación con 75-150 kg/ha de P2O5 y 0 a 30 kg/ha de K2O. Lo anterior equivaldría, aproximadamente a grados comerciales 10-30-0, 10-30-5, 10-30-5, 10-25-0, 10-25-5. Las escorias thomas, aplicadas al momento de la siembra fueron una buena fuente de P para la cebada.Cebada-Hordeum vulgar