106 research outputs found

    Noncommutative vector bundles over fuzzy CP^N and their covariant derivatives

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    We generalise the construction of fuzzy CP^N in a manner that allows us to access all noncommutative equivariant complex vector bundles over this space. We give a simplified construction of polarization tensors on S^2 that generalizes to complex projective space, identify Laplacians and natural noncommutative covariant derivative operators that map between the modules that describe noncommuative sections. In the process we find a natural generalization of the Schwinger-Jordan construction to su(n) and identify composite oscillators that obey a Heisenberg algebra on an appropriate Fock space.Comment: 34 pages, v2 contains minor corrections to the published versio

    The Luminescent Properties and Atomic Structures of As-Grown and Annealed Nanostructured Silicon Rich Oxide Thin Films

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    Not long ago, we developed a theoretical model to describe a set of chemical reactions that can potentially occur during the process of obtaining Silicon Rich Oxide (SRO) films, an off stoichiometry material, notwithstanding the technique used to grow such films. In order to elucidate the physical chemistry properties of such material, we suggested the chemical reactions that occur during the process of growing of SRO films in particular for the case of the Low Pressure Chemical Vapor Deposition (LPCVD) technique in the aforementioned model. The present paper represents a step further with respect to the previous (published) work, since it is dedicated to the calculation by Density Functional Theory (DFT) of the optical and electronic properties of the as-grown and annealed SRO structures theoretically predicted on the basis of the previous work. In this work, we suggest and evaluate either some types of molecules or resulting nanostructures and we predict theoretically, by applying the DFT, the contribution that they may have to the phenomenon of luminescence (PL), which is experimentally measured in SRO films. We evaluated the optical and electronic properties of both the as-grown and the annealed structures

    Perfil de pacientes hematológicos atendidos en un servicio de urgencias hospitalario

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    Poster [PC-355] Introducción: Durante los últimos años existe un aumento progresivo en la demanda de asistencia en los servicios de urgencias hospitalarios (SUH), tanto generales como pediátricos. Los pacientes hematológicos presentan numerosos episodios clínicos que precisan valoración clínica urgente y dada la facilidad de acceso a los SUH emplean este medio. Métodos: Estudio descriptivo observacional de las urgencias en pacientes con patología hematológica atendidas en el Servicio de Urgencias del Hospital Universitario Miguel Servet de Zaragoza (Hospital de tercer nivel). Periodo de estudio (Enero 2017-Diciembre 2017). Criterios de inclusión: Paciente: s con diagnóstico hematológico según la clasificación CIE-9 en el informe de alta de urgencias. Grupo de pacientes adultos (> 14 años): atendidos en el Hospital General, y grupo de pacientes pediátricos (< 14 años): atendidos en el Hospital Infantil. Variables analizadas: edad, sexo, grupo de patología y nivel de triaje. Datos recogidos a través del registro derivado de la Base de Datos generada por el aplicativo informático “Puesto Clínico Hospitalario de Urgencias”, que da soporte a la actividad asistencial de los servicios de urgencias hospitalarios de Aragón. Se obtuvo autorización correspondiente del centro y del SUH para el acceso a los datos informáticos. Resultados: Muestra total de 2193 pacientes: 1928 en el grupo de adultos y 265 en el grupo pediátrico. En el grupo de adultos la edad media de consulta en SUH fue de 71, 4 años (DE: 18.10), siendo el subgrupo de 81-90 años el que más frecuentemente acude (31.74%). En la población infantil la edad media de consulta fue de 6, 39 años (DE: 4.54), siendo entre los 0-2 años la edad que más frecuenta Urgencias (19.62%). Respecto a la distribución según sexo, el 55% de las consultas son realizadas por mujeres y el 45% por hombres. Sin embargo, en la población infantil el 52% de las consultas son realizadas por niños y el 48% por niñas. En el análisis según grupo de enfermedad: el grupo pediátrico consulta más frecuentemente por enfermedades de hemostasia (47.17%), mientras que los adultos consultan más por enfermedades de serie roja (61.28%). En ambos grupos, las consultas realizadas en Urgencias son de gran complejidad con una prioridad elevada de asistencia. El 93% de la patología en adultos y el 71% de la patología infantil hematológica es triada con niveles I-III de urgencia y tiempos asistenciales reducidos. Conclusiones: El comportamiento de las enfermedades hematológicas varía en función de la edad, el sexo y el tipo de enfermedad. La patología hematológica tiene un gran impacto dentro de los servicios de urgencias hospitalarios, dado que estos pacientes presentan un perfil complejo que requerirá diagnóstico y tratamiento rápido por la gravedad del tipo de complicaciones que asocian. En consonancia con la población envejecida, los pacientes que más demandan la atención en Urgencias y de forma repetida, son adultos muy mayores (81-90 años) pudiéndose plantear circuitos de asistencia urgente diferentes para estos pacientes

    Oxidative stress is associated with an increased antioxidant defense in elderly subjects: a multilevel approach

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    Background: Studies of associations between plasma GSH-Px activity and cardiovascular risk factors have been done in humans, and contradictory results have been reported. The aim of our study was to assess the association between the scavenger antioxidant enzyme glutathione peroxidase (GSH-Px) activity in plasma and the presence of novel and classical cardiovascular risk factors in elderly patients. Methods: We performed a cross-sectional study with baseline data from a subsample of the PREDIMED (PREvencio´n con DIeta MEDiterra´nea) study in Spain. Participants were 1,060 asymptomatic subjects at high risk for cardiovascular disease (CVD), aged 55 to 80, selected from 8 primary health care centers (PHCCs). We assessed classical CVD risk factors, plasma oxidized low-density lipoproteins (ox-LDL), and glutathione peroxidase (GSH-Px) using multilevel statistical procedures. Results: Mean GSH-Px value was 612 U/L (SE: 12 U/L), with variation between PHCCs ranging from 549 to 674 U/L (Variance = 1013.5; P,0.001). Between-participants variability within a PHCC accounted for 89% of the total variation. Both glucose and oxidized LDL were positively associated with GSH-Px activity after adjustment for possible confounder variables (P = 0.03 and P = 0.01, respectively). Conclusion: In a population at high cardiovascular risk, a positive linear association was observed between plasma GSH-Px activity and both glucose and ox-LDL levels. The high GSH-Px activity observed when an oxidative stress situation occurred, such as hyperglycemia and lipid oxidative damage, could be interpreted as a healthy defensive response against oxidative injury in our cardiovascular risk population

    Marine Biodiversity in the Caribbean: Regional Estimates and Distribution Patterns

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    This paper provides an analysis of the distribution patterns of marine biodiversity and summarizes the major activities of the Census of Marine Life program in the Caribbean region. The coastal Caribbean region is a large marine ecosystem (LME) characterized by coral reefs, mangroves, and seagrasses, but including other environments, such as sandy beaches and rocky shores. These tropical ecosystems incorporate a high diversity of associated flora and fauna, and the nations that border the Caribbean collectively encompass a major global marine biodiversity hot spot. We analyze the state of knowledge of marine biodiversity based on the geographic distribution of georeferenced species records and regional taxonomic lists. A total of 12,046 marine species are reported in this paper for the Caribbean region. These include representatives from 31 animal phyla, two plant phyla, one group of Chromista, and three groups of Protoctista. Sampling effort has been greatest in shallow, nearshore waters, where there is relatively good coverage of species records; offshore and deep environments have been less studied. Additionally, we found that the currently accepted classification of marine ecoregions of the Caribbean did not apply for the benthic distributions of five relatively well known taxonomic groups. Coastal species richness tends to concentrate along the Antillean arc (Cuba to the southernmost Antilles) and the northern coast of South America (Venezuela – Colombia), while no pattern can be observed in the deep sea with the available data. Several factors make it impossible to determine the extent to which these distribution patterns accurately reflect the true situation for marine biodiversity in general: (1) highly localized concentrations of collecting effort and a lack of collecting in many areas and ecosystems, (2) high variability among collecting methods, (3) limited taxonomic expertise for many groups, and (4) differing levels of activity in the study of different taxa

    Anti-tumour necrosis factor discontinuation in inflammatory bowel disease patients in remission: study protocol of a prospective, multicentre, randomized clinical trial

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    Background: Patients with inflammatory bowel disease who achieve remission with anti-tumour necrosis factor (anti-TNF) drugs may have treatment withdrawn due to safety concerns and cost considerations, but there is a lack of prospective, controlled data investigating this strategy. The primary study aim is to compare the rates of clinical remission at 1?year in patients who discontinue anti-TNF treatment versus those who continue treatment. Methods: This is an ongoing, prospective, double-blind, multicentre, randomized, placebo-controlled study in patients with Crohn?s disease or ulcerative colitis who have achieved clinical remission for ?6?months with an anti-TNF treatment and an immunosuppressant. Patients are being randomized 1:1 to discontinue anti-TNF therapy or continue therapy. Randomization stratifies patients by the type of inflammatory bowel disease and drug (infliximab versus adalimumab) at study inclusion. The primary endpoint of the study is sustained clinical remission at 1?year. Other endpoints include endoscopic and radiological activity, patient-reported outcomes (quality of life, work productivity), safety and predictive factors for relapse. The required sample size is 194 patients. In addition to the main analysis (discontinuation versus continuation), subanalyses will include stratification by type of inflammatory bowel disease, phenotype and previous treatment. Biological samples will be obtained to identify factors predictive of relapse after treatment withdrawal. Results: Enrolment began in 2016, and the study is expected to end in 2020. Conclusions: This study will contribute prospective, controlled data on outcomes and predictors of relapse in patients with inflammatory bowel disease after withdrawal of anti-TNF agents following achievement of clinical remission. Clinical trial reference number: EudraCT 2015-001410-1

    Multimessenger NuEM Alerts with AMON

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    The Astrophysical Multimessenger Observatory Network (AMON), has developed a real-time multi-messenger alert system. The system performs coincidence analyses of datasets from gamma-ray and neutrino detectors, making the Neutrino-Electromagnetic (NuEM) alert channel. For these analyses, AMON takes advantage of sub-threshold events, i.e., events that by themselves are not significant in the individual detectors. The main purpose of this channel is to search for gamma-ray counterparts of neutrino events. We will describe the different analyses that make-up this channel and present a selection of recent results

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
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