445 research outputs found

    Topological quantum criticality from multiplicative topological phases

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    Symmetry-protected topological phases (SPTs) characterized by short-range entanglement include many states essential to understanding of topological condensed matter physics, and the extension to gapless SPTs provides essential understanding of their consequences. In this work, we identify a fundamental connection between gapless SPTs and recently-introduced multiplicative topological phases, demonstrating that multiplicative topological phases are an intuitive and general approach to realizing concrete models for gapless SPTs. In particular, they are naturally well-suited to realizing higher-dimensional, stable, and intrinsic gapless SPTs through combination of canonical topological insulator and semimetal models with critical gapless models in symmetry-protected tensor product constructions, opening avenues to far broader and deeper investigation of topology via short-range entanglement

    Respuesta fisiológica y productiva de novillos engordados con un sistema de enfriamiento a espacio abierto en un clima árido y seco

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    Evaluation of the effects of an open space cooling system on weight gain, respiration rate and serum thyroid hormone (T3 and T4) levels in feedlot steers was done using 60 Holstein steers (344 kg) allotted randomly in two treatments: a control with only shade in the corral (n=30), and a cooling with an open space cooling system (n=30). Daily maximum temperature-humidity index (THI) ranged from 82 to 88 during the 12-week study period. The open space cooling system consisted of a fan with 2.4 m diameter blade that displaced 1,416 m3 of air per minute and had a 90º oscillation range, and sprinklers. The fan was installed at 8 m distance on the south side of the shade. Water discharge was 12 L per minute over a 7 h period. Body weight and thyroid hormone levels were measured every two weeks and respiration rate twice a week (1400). Data were analyzed by repeated measures, including initial weight as a covariate. Daily weight gain was different (PCon objeto de evaluar el efecto de un sistema de enfriamiento a espacio abierto sobre la ganancia de peso, frecuencia de respiración y niveles sanguíneos de triiodotironina (T3) y tiroxina (T4) durante el verano, 60 novillos Holstein fueron asignados aleatoriamente a un grupo testigo con únicamente sombra y un segundo grupo con sombra, más enfriamiento. Durante el experimento se registró un Índice de temperatura-humedad máximo que oscilo entre 82 a 88. El sistema de enfriamiento colocado a 8 m a partir de la sombra, consistió de una hélice de 2.4 m de diámetro produciendo 1,416 m3/min de aire con una rotación de 90° y un flujo de agua de 12 L/min. El peso corporal y los niveles de hormonas fueron registrados cada dos semanas, mientras la frecuencia de respiración (1400) en dos ocasiones por semana. Los datos fueron analizados con un diseño de mediciones repetidas, incluyendo el peso inicial como covariable. La ganancia de peso fue mayor (

    Lung Radiology and Pulmonary Function of Children Chronically Exposed to Air Pollution

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    We analyzed the chest radiographs (CXRs) of 249 clinically healthy children, 230 from southwest Mexico City and 19 from Tlaxcala. In contrast to children from Tlaxcala, children from southwest Mexico City were chronically exposed to ozone levels exceeding the U.S. National Ambient Air Quality Standards for an average of 4.7 hr/day and to concentrations of particulate matter (PM) with aerodynamic diameters ≤2.5 μm (PM(2.5)) above the annual standard. CXRs of Mexico City children demonstrated bilateral hyperinflation (151 of 230) and increased linear markings (121 of 230). Hyperinflation and interstitial markings were significantly more common in Mexico City children (p < 0.0002 and 0.00006 respectively). Mexico City boys had a higher probability of developing interstitial markings with age (p = 0.004). Computed tomography (CT) scans were obtained in 25 selected Mexico City children with abnormal CXRs. Mild bronchial wall thickening was seen in 10 of 25, prominent central airways in 4 of 25, air trapping in 8 of 21, and pulmonary nodules in 2 of 21. Only 7.8% of Mexico City children had abnormal lung function tests based on predicted values. These findings are consistent with bronchiolar, peribronchiolar, and/or alveolar duct inflammation, possibly caused by ozone, PM, and lipopolysaccharide exposure. The epidemiologic implications of these findings are important for children residing in polluted environments, because bronchiolar disease could lead to chronic pulmonary disease later in life

    Tratamiento de agua salobre mediante nanofiltración solar a baja presión para irrigación

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    En este trabajo se presenta una solución para tratar agua salobre mediante nanofiltración fotovoltaica a baja presión (NF-FV-BP), orientada a la habilitación de tierras improductivas en términos agrícolas. La zona de estudio fue la región hidrológica RH26 del desierto de Chihuahua (subcuenca Aj Río Verde), la cual se consideró representativa de cuencas con sedimento salino debido a drenaje ineficiente. El agua subterránea disponible presentó un alto contenido de sulfatos (1 863 mg/l) y 2 195 mg/l de sólidos disueltos totales (SDT), lo que compromete su viabilidad para riego. El tratamiento de NF-FV-BP se propuso por ser apto para la remoción de iones divalentes como los sulfatos, para así disminuir la concentración de SDT. El tratamiento se realizó utilizando tanto agua sintética como la disponible en la región de estudio, determinando la eficiencia de remoción de SDT y de sulfatos, energía específica, producción diaria y viabilidad de su operación en campo. En los resultados se observó que la eficiencia de remoción de SDT, energía específica y productividad se relacionan con la irradiación, y se obtuvo una correlación lineal para cada caso. Los sulfatos y los SDT se redujeron en un 98.21 y 75.15%, respectivamente, a una irradiación igual o superior a 750 W/m2 , con una energía específica de 1.94 kWh/m3 . En campo, la productividad de permeado resultó de 3.2 m3 /día, a insolación promedio de 6.3 hora pico/día en el plano de los módulos fotovoltaicos. La operación continua del prototipo durante cuatro meses por parte de usuarios mostró viabilidad de la solución propuesta

    GM and KM immunoglobulin allotypes in the Galician population: new insights into the peopling of the Iberian Peninsula

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    <p>Abstract</p> <p>Background</p> <p>The current genetic structure of Iberian populations has presumably been affected by the complex orography of its territory, the different people and civilizations that settled there, its ancient and complex history, the diverse and persistent sociocultural patterns in its different regions, and also by the effects of the Iberian Peninsula representing a refugium area after the last glacial maximum. This paper presents the first data on <it>GM </it>and <it>KM </it>immunoglobulin allotypes in the Galician population and, thus, provides further insights into the extent of genetic diversity in populations settled in the geographic extremes of the Cantabrian region of northern Spain. Furthermore, the genetic relationships of Galicians with other European populations have been investigated.</p> <p>Results</p> <p>Galician population shows a genetic profile for <it>GM </it>haplotypes that is defined by the high presence of the European Mediterranean <it>GM</it>*<it>3 23 5* </it>haplotype, and the relatively high incidence of the African marker <it>GM*1,17 23' 5*</it>. Data based on comparisons between Galician and other Spanish populations (mainly from the north of the peninsula) reveal a poor correlation between geographic and genetic distances (<it>r </it>= 0.30, <it>P </it>= 0.105), a noticeable but variable genetic distances between Galician and Basque subpopulations, and a rather close genetic affinity between Galicia and Valencia, populations which are geographically separated by a long distance and have quite dissimilar cultures and histories. Interestingly, Galicia occupies a central position in the European genetic map, despite being geographically placed at one extreme of the European continent, while displaying a close genetic proximity to Portugal, a finding that is consistent with their shared histories over centuries.</p> <p>Conclusion</p> <p>These findings suggest that the population of Galicia is the result of a relatively balanced mixture of European populations or of the ancestral populations that gave rise to them. This would support the importance of the migratory movements that have taken place in Europe over the course of recent human history and their effects on the European genetic landscape.</p

    Dermatitis herpetiforme en mujer joven de la Amazonía peruana

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    Dermatitis herpetiforme is an autoimmune disease characterized by the presence of vesicular lesions and itching on the extensor surface of the limbs, buttocks, and lower back. The clinical case of a 21-year-old woman, a native of and from Iquitos, is presented. She presented multiple painful, itchy vesicles with an erythematous and purulent base on both elbows for a month. Subsequently, these lesions spread to both knees, and intense itching was added. The patient experienced alternating periods of remission and exacerbation. The correlation of the clinical picture, serological and biopsy results, along with the therapeutic response to dapsona, confirmed the diagnosis of dermatitis herpetiforme, with a favorable evolution and remission of the disease.La dermatitis herpetiforme es una enfermedad autoinmune que se caracteriza por la presencia de lesiones vesiculares y prurito en la superficie extensora de las extremidades, nalgas y parte baja de la espalda. Se presenta el caso clínico de una mujer de 21 años, natural y procedente de Iquitos, que presentó múltiples vesículas dolorosas, pruriginosas, de base eritematosa y purulentas en ambos codos durante un mes. Posteriormente, estas lesiones se diseminaron a ambas rodillas y se agregó prurito intenso. La paciente experimentó períodos alternantes de remisión y exacerbación. La correlación del cuadro clínico, resultados serológicos y de biopsia, junto con respuesta terapéutica a la dapsona confirmaron el diagnóstico de dermatitis herpetiforme, con una evolución favorable y remisión de la enfermedad

    Charged-to-neutral correlation at forward rapidity in Au+Au collisions at sNN\sqrt{s_{NN}}=200 GeV

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    Event-by-event fluctuations of the ratio of inclusive charged to photon multiplicities at forward rapidity in Au+Au collision at sNN\sqrt{s_{NN}}=200 GeV have been studied. Dominant contribution to such fluctuations is expected to come from correlated production of charged and neutral pions. We search for evidences of dynamical fluctuations of different physical origins. Observables constructed out of moments of multiplicities are used as measures of fluctuations. Mixed events and model calculations are used as baselines. Results are compared to the dynamical net-charge fluctuations measured in the same acceptance. A non-zero statistically significant signal of dynamical fluctuations is observed in excess to the model prediction when charged particles and photons are measured in the same acceptance. We find that, unlike dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated by correlation due to particle decay. Results are compared to the expectations based on the generic production mechanism of pions due to isospin symmetry, for which no significant (<1%) deviation is observed.Comment: 14 pages, 6 figure

    Beam energy dependent two-pion interferometry and the freeze-out eccentricity of pions in heavy ion collisions at STAR

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    We present results of analyses of two-pion interferometry in Au+Au collisions at sNN\sqrt{s_{NN}} = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV measured in the STAR detector as part of the RHIC Beam Energy Scan program. The extracted correlation lengths (HBT radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mTm_{T}) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.Comment: 27 pages; 27 figure
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