7,172 research outputs found

    2GHz MIMO channel model from experimental outdoor data analysis in UMTS

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    The key objective of this work was to obtain a MIMO model for a line of sight (LOS) channel component as well as the covariance matrix for a non-LOS deployment. A maximum likelihood criteria is applied to obtain a LOS spatial signature vector and a NLOS covariance matrix derived from channel measurements taken in the 2 GHz UMTS spectrum for an urban deployment in Bristol (UK). Different user equipment deployments were considered to represent both LOS and NLOS, as well as static and dynamic (motion) situations. The parameters of interest were estimated from these data and the fitness model was satisfactorily evaluated in all cases. Further, the Kronecker product between transmitter and receiver matrices was evaluated in order to simplify the model, for both, LOS and NLOS cases, including polarization diversity cases.The key objective of this work was to obtain a MIMO model for a line of sight (LOS) channel component as well as the covariance matrix for a non-LOS deployment. A maximum likelihood criteria is applied to obtain a LOS spatial signature vector and a NLOS covariance matrix derived from channel measurements taken in the 2 GHz UMTS spectrum for an urban deployment in Bristol (UK). Different user equipment deployments were considered to represent both LOS and NLOS, as well as static and dynamic (motion) situations. The parameters of interest were estimated from these data and the fitness model was satisfactorily evaluated in all cases. Further, the Kronecker product between transmitter and receiver matrices was evaluated in order to simplify the model, for both, LOS and NLOS cases, including polarization diversity cases

    Breaking Tri-bimaximal Mixing and Large θ13\theta_{13}

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    The long baseline neutrino experiment, T2K, and the reactor experiment, Double Chooz will soon present new data. If we expect sinθ13\sin\theta_{13} to be 0.1-0.2, which is close to the present experimental upper bound, we should not persist in the paradigm of the tri-bimaximal mixing. We discuss breaking the tri-bimaximal mixing by adding a simple mass matrix, which could be derived from some non-Abelian discrete symmetries. It is found that sinθ13=0.10.2\sin\theta_{13}=0.1-0.2 is expected in our model independent analysis of the generalized mass matrix for the normal or inverted hierarchical neutrino mass spectrum. On the other hand, sin2θ23\sin^2\theta_{23} and sin2θ12\sin^2\theta_{12} are expected to be not far from 1/2 and 1/3, respectively. As a typical example, we also discuss the A4A_4 flavor model with the 1 and 1' flavons, which break the tri-bimaximal mixing considerably. In this modified version of the Altarelli and Feruglio model, sinθ13\sin\theta_{13} is predicted to be around 0.15 in the case of the normal hierarchical neutrino masses m3m2,m1m_3\gg m_2, m_1, and 0.2 in the case of the inverted hierarchy m3m2,m1m_3\ll m_2, m_1. The form of the neutrino mass matrix looks rather interesting --- it is suggestive of other discrete symmetries as well.Comment: 10 pages, 12 figures, final versio

    Catechol estrogens stimulate insulin secretion in pancreatic β-cells via activation of the transient receptor potential A1 (TRPA1) channel

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    Estrogen hormones play an important role in controlling glucose homeostasis and pancreatic β-cell function. Despite the significance of estrogen hormones for regulation of glucose metabolism, little is known about the roles of endogenous estrogen metabolites in modulating pancreatic β-cell function. In this study, we evaluated the effects of major natural estrogen metabolites, catechol estrogens, on insulin secretion in pancreatic β-cells. We show that catechol estrogens, hydroxylated at positions C2 and C4 of the steroid A ring, rapidly potentiated glucose-induced insulin secretion via a nongenomic mechanism. 2-Hydroxyestrone, the most abundant endogenous estrogen metabolite, was more efficacious in stimulating insulin secretion than any other tested catechol estrogens. In insulin-secreting cells, catechol estrogens produced rapid activation of calcium influx and elevation in cytosolic free calcium. Catechol estrogens also generated sustained elevations in cytosolic free calcium and evoked inward ion current in HEK293 cells expressing the transient receptor potential A1 (TRPA1) cation channel. Calcium influx and insulin secretion stimulated by estrogen metabolites were dependent on the TRPA1 activity and inhibited with the channel-specific pharmacological antagonists or the siRNA. Our results suggest the role of estrogen metabolism in a direct regulation of TRPA1 activity with potential implications for metabolic diseases

    Evaluation of decellularization of porcine pericardium: Decellularization of porcine pericardium

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    The porcine pericardium has been used for its great potential as a biological scaffold, produced from the extracellular matrix (ECM) and used mainly in surgeries reconstructive, tissue repair and surgical procedures for corneal reconstruction. The adequate preservation and biocompatibility of the pericardial ECM structure during the decellularization process is fundamental, the biggest challenge being the total removal of cellular material without damage to the structure. All agents used in decellularization change the composition and cause some damage to the ultrastructure. Sodium Dodecil Sulfate (SDS) is the most effective for removing cell residue from tissue compared to other detergents, which is also the most used for the decellularization process. This work aimed to test 3 different concentrations of SDS, in order to assess the concentration (0.1, 0.5 and 1%) that best preserves the structure of the ECM pericardial. In addition, we listed the type of daily wash to make the process more effective (only distilled water or PBS 1x), in order to assess the concentration capable of decellularizing the tissue and better preserving the pericardial ECM. The concentration of SDS at 1%, when compared to the lowest concentrations of 0.1 and 0.5%, was more effective in the decellularization process, however it did not obtain good results in the preservation of the ECM. Regarding daily washing, there was no difference in the frequency assessed in the experimental groups

    An Agent-Based Decision Support System for Hospitals Emergency Departments

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    AbstractModeling and simulation have been shown to be useful tools in many areas of the Healthcare operational management, field in which there is probably no area more dynamic and complex than hospital emergency departments (ED). This paper presents the results of an ongoing project that is being carried out by the Research Group in Individual Oriented Modeling (IoM) of the University Autonoma of Barcelona (UAB) with the participation of Hospital of Sabadell ED Staff Team. Its general objective is creating a simulator that, used as decision support system (DSS), aids the heads of the ED to make the best informed decisions possible. The defined ED model is a pure Agent-Based Model, formed entirely of the rules governing the behavior of the individual agents which populate the system. Two distinct types of agents have been identified, active and passive. Active agents represent human actors, meanwhile passive agents represent services and other reactive systems. The actions of agents and the communication between them will be represented using Moore state machines extended to include probabilistic transitions. The model also includes the environment in which agents move and interact. With the aim of verifying the proposed model an initial simulation has been created using NetLogo, an agent-based simulation environment well suited for modeling complex systems

    Using an Agent-based Simulation for Predicting the Effects of Patients Derivation Policies in Emergency Departments

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    AbstractThe increasing demand of urgent care, overcrowding of hospital emergency departments (ED) and limited economic resources are phenomena shared by health systems around the world. It is estimated that up to 50% of patients that are attended in ED have non complex conditions that could be resolved in ambulatory care services. The derivation of less complex cases from the ED to other health care devices seems an essential measure to allocate properly the demand of care service between the different care units. This paper presents the results of an experiment carried out with the objective of analyzing the effects on the ED (patients’ Length of Stay, the number of patients attended and the level of activity of ED Staff) of different derivation policies. The experiment has been done with data of the Hospital of Sabadell (a big hospital, one of the most important in Catalonia, Spain), making use of an Agent-Based model and simulation formed entirely of the rules governing the behaviour of the individual agents which populate the ED, and due to the great amount of data that should be computed, using High Performance Computing

    Evaluación del Proyecto Epikouros de Inserción Sociolaboral de Inmigrantes

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    El proyecto Epikouros del Ayuntamiento de Barcelona representa un modelo de servicio específico de orientación para la inserción sociolaboral dirigido a personas procedentes de la inmigración exterior y con situación socioeconómica deficitaria. El proyecto pretendía responder a las necesidad peculiares que estas personas tienen en su proceso de inserción sociolaboral en la ciudad de Barcelona. Su finalidad fue acercar a los colectivos, asociaciones y personas inmigrantes los distintos servicios de inserción sociolaboral normalizados del Ayuntamiento de Barcelona, a la vez que facilitar la coordinación y adaptación de éstos a las necesidades diferenciales que tiene esta población. El proyecto atendió a un total de 235 personas inmigrantes

    Diversidad y Multiculturalidad

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    Esta ponencia se enmarca en la línea de anteriores trabajos nuestros, en los que se ha intentado ofrecer el panorama general de la investigación llevada a cabo en el campo de la diferenciación educativa, y, más en concreto de la educación intercultural. En «Diseños y metodologías de investigación desde la perspectiva de la educación intercultural » (Bartolomé, 1992), tras una breve clarificación de términos asociados a la educación multicultural, analizábamos los principales métodos de investigación y campos de estudio que se habían desarrollado a lo largo de este siglo en el ámbito mundial. En «Modelos de investigación en la intervención educativa diferencial» (Bartolomé, Cabrera, F., Espín, J., Marín, M.A., Del Rincón, D. y Rodríguez, M., 1993) nos centrábamos en un marco más amplio, intentando abordar el estado de la investigación en ese momento en cada una de las áreas temáticas, al tiempo que profundizábamos en los principales problemas metodológicos hallados

    Protocol for studying cough frequency in people with pulmonary tuberculosis.

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    INTRODUCTION: Cough is a key symptom of tuberculosis (TB) as well as the main cause of transmission. However, a recent literature review found that cough frequency (number of coughs per hour) in patients with TB has only been studied once, in 1969. The main aim of this study is to describe cough frequency patterns before and after the start of TB treatment and to determine baseline factors that affect cough frequency in these patients. Secondarily, we will evaluate the correlation between cough frequency and TB microbiological resolution. METHODS: This study will select participants with culture confirmed TB from 2 tertiary hospitals in Lima, Peru. We estimated that a sample size of 107 patients was sufficient to detect clinically significant changes in cough frequency. Participants will initially be evaluated through questionnaires, radiology, microscopic observation drug susceptibility broth TB-culture, auramine smear microscopy and cough recordings. This cohort will be followed for the initial 60 days of anti-TB treatment, and throughout the study several microbiological samples as well as 24 h recordings will be collected. We will describe the variability of cough episodes and determine its association with baseline laboratory parameters of pulmonary TB. In addition, we will analyse the reduction of cough frequency in predicting TB cure, adjusted for potential confounders. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the ethics committees at each participating hospital in Lima, Peru, Asociación Benéfica PRISMA in Lima, Peru, the Universidad Peruana Cayetano Heredia in Lima, Peru and Johns Hopkins University in Baltimore, USA. We aim to publish and disseminate our findings in peer-reviewed journals. We also expect to create and maintain an online repository for TB cough sounds as well as the statistical analysis employed
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