474 research outputs found

    Development of a moisture-in-solid-insulation sensor for power transformers

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    Moisture is an important variable that must be kept under control to guarantee a safe operation of power transformers. Because of the hydrophilic character of cellulose, water mainly remains in the solid insulation, while just a few parts per million are dissolved in oil. The distribution of moisture between paper and oil is not static, but varies depending on the insulation temperature, and thus, water migration processes take place continuously during transformers operation. In this work, a sensor is presented that allows the determination of the moisture content of the transformer solid insulation in the steady state and during the moisture migration processes. The main objective of the design is that the electrodes of the sensor should not obstruct the movement of water from the solid insulation to the oil, so the proposed prototype uses a metallic-mesh electrode to do the measurements. The measurement setup is based on the characterization of the insulation dielectric response by means of the frequency dielectric spectroscopy (FDS) method. The sensitivity of the proposed sensor has been tested on samples with a moisture content within 1% to 5%, demonstrating the good sensitivity and repeatability of the measurements.This work has been supported by the Spanish Government under Contract DPI2012-35819

    On the Fluid Dynamics of the Make-Up Inlet Air and the Prediction of Anomalous Fire Dynamics in a Large-Scale Facility

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    The present paper is focused on the fluid dynamics of the make-up air at the vents in case of an atrium fire, its influence on the fire-induced conditions and the necessity of properly model it to obtain an accurate numerical prediction. For this aim, experimental data from two full-scale atrium fire tests conducted in a 20 m cubic facility, with venting conditions involving mechanical smoke exhaust and make-up air velocities larger than 1 m/s, and with different fire powers, are presented. Subsequent numerical simulations of these tests have been performed with the code Fire Dynamics Simulator v5.5.3. Two different approaches have been followed to simulate the make-up air inlet fluid dynamics, involving one domain which only considers the inside of the building and another which includes part of the outside. In the former simulations, anomalous phenomena around the fire appear, while the inclusion of the exterior domain provides with a completely different fluid dynamics inside the facility which agrees better with the experimental data. A detailed analysis of the fluid mechanics at the air inlet vents is conducted to explain these discrepancies. Finally, further simulations are performed varying the make-up area to assess the appearance of the aforementioned phenomenon.This research was supported by the Spanish MCyT and Junta de Andalucia under Projects # DPI2008-06624-C03-02 and # P07-TEP02693, respectively. CGM wants to acknowledge the research stay grants IAC-2010-3 and A-13-2010 from the Junta de Andalucia and the University of Jaén, respectivel

    Growth hormone biases amygdala network activation after fear learning

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    Prolonged stress exposure is a risk factor for developing posttraumatic stress disorder, a disorder characterized by the ‘over-encoding’ of a traumatic experience. A potential mechanism by which this occurs is through upregulation of growth hormone (GH) in the amygdala. Here we test the hypotheses that GH promotes the over-encoding of fearful memories by increasing the number of neurons activated during memory encoding and biasing the allocation of neuronal activation, one aspect of the process by which neurons compete to encode memories, to favor neurons that have stronger inputs. Viral overexpression of GH in the amygdala increased the number of amygdala cells activated by fear memory formation. GH-overexpressing cells were especially biased to express the immediate early gene c-Fos after fear conditioning, revealing strong autocrine actions of GH in the amygdala. In addition, we observed dramatically enhanced dendritic spine density in GH-overexpressing neurons. These data elucidate a previously unrecognized autocrine role for GH in the regulation of amygdala neuron function and identify specific mechanisms by which chronic stress, by enhancing GH in the amygdala, may predispose an individual to excessive fear memory formation.National Institute of Mental Health (U.S.) (NIMH R01 MH084966)United States. Defense Advanced Research Projects Agency (DARPA grant W911NF-10-1-0059)United States. Army Research Offic

    Propiedades reológicas y termofísicas de pulpa de sanky (Corryocactus brevistylus) y aguaymanto (Physalis peruviana L.)

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    El Perú tiene una amplia gama de frutos andinos, ricos en nutrientes y dan un buen aporte para la salud de los consumidores. No obstante, estos tienen un bajo consumo como producto fresco y/o procesado, incluido el sanky y aguaymanto, lo cual puede ser atribuido a que no se conoce sus características reológicas y propiedades termofísicas. El objetivo de la investigación fue determinar los parámetros reológicos y propiedades termofísicas de pulpa de sanky (Corryocactus brevistylus) y aguaymanto (Physalis peruviana L.) a diferentes concentraciones de sólidos y temperaturas. Las pulpas de frutos andinos (sanky y aguaymanto) fueron concentradas a 25, 45 y 65 °Brix y temperaturas de 25, 40 y 60 °C. Para evaluar el efecto de la concentración y la temperatura sobre las parámetros reológicos (app, n y k) se aplicó un diseño factorial 32, para el efecto de la temperatura sobre los módulos oscilatorios (G`, G”, * y tan δ) y el efecto de la concentración sobre las propiedades termofísicas (, Cp, y ) se aplicó un DCA. Ambas pulpas presentaron un comportamiento pseudoplastico. El análisis de varianza mostró que las variables independientes (°Brix y °C) generaron diferencias significativas (p<0.05) en los parámetros reológicos de las pulpas, se presentó una relación inversa entre ambas variables independientes y los mejores valores, según la gráfica de superficie respuesta, se encontraban a una mayor concentración y menor temperatura. De igual forma, la temperatura generó diferencia significativa (p<0.05) entre los módulos oscilatorios de las muestras, la pulpa de sanky presentó un comportamiento semi-sólido en las tres temperaturas y el aguaymanto un comportamiento semi-liquido en las muestras de 25 y 40 °C y semi-sólido en la muestra a 60 °C. La concentración también generó diferencias significativas (p<0.05) en las propiedades termofísicas de las pulpas, estas propiedades descendieron conforme aumentaba la concentración.TesisLIMAEscuela Profesional de Ingeniería y ArquitecturaProcesamiento, seguridad y gestión en la Industria alimentari

    La arquitectura de software basada en microservicios: Una revisión sistemática de la literatura

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    El estilo de arquitectura de software basado en microservicios se ha ido convirtiendo en un tema de interés debido a los múltiples beneficios que otorga a las organizaciones que lo adoptan para el desarrollo de sus sistemas de software. Este estilo propone desarrollar la aplicación como un conjunto de pequeños servicios, cada uno ejecutándose independientemente y comunicándose entre sí. El presente artículo busca identificar patrones, buenas prácticas y técnicas relacionadas con la arquitectura de software basada en microservicios. Para la identificación de los elementos mencionados se realizó una revisión sistemática de la literatura en las bases de datos reconocidas. De un total de 394 artículos revisados, se identificaron 24 artículos que hacen referencia a la arquitectura basada en microservicios y sus elementos. Luego de realizar una revisión sistemática de la literatura se pudo identificar 8 patrones en los cuales se destaca la contenerización de servicios y la descomposición de monolitos, 1 técnica relacionada a la migración de aplicaciones monolíticas a microservicios y 4 buenas prácticas destacadas las cuales pertenecen a DevOps.Trabajo de investigaciónLIMAEscuela Profesional de Ingeniería de SistemasIngeniería de Softwar

    Glass-Transition Dynamics of Mixtures of Linear Poly(Vinyl Methyl Ether) with Single-Chain Polymer Nanoparticles: Evidence of a New Type of Nanocomposite Materials

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    Single-chain polymer nanoparticles (SCNPs) obtained through chain collapse by intramolecular cross-linking are attracting increasing interest as components of all-polymer nanocomposites, among other applications. We present a dielectric relaxation study on the dynamics of mixtures of poly(vinyl methyl ether) (PVME) and polystyrene (PS)-based SCNPs with various compositions. Analogous dielectric measurements on a miscible blend of PVME with the linear precursor chains of the SCNPs are taken as reference for this study. Both systems present completely different behaviors: While the blend with the linear precursor presents dynamics very similar to that reported for PVME/PS miscible blends, in the PVME/SCNP mixtures there are an appreciable amount of PVME segments that are barely affected by the presence of SCNPs, which nearly vanishes only for mixtures with high SCNP content. Interestingly, in the frame of a simple two-phase system, our findings point towards the existence of a SCNP-rich phase with a constant PVME fraction, regardless of the overall concentration of the mixture. Moreover, the dynamics of the PVME segments in this SCNP-rich phase display an extreme dynamic heterogeneity, a signature of constraint effects.This research was funded by Eusko Jaurlaritza project code: IT-654-13 and the Ministerio de Economia y Competitividad project code: MAT2015-63704-P (MINECO/FEDER, UE)

    Role of the Intracellular pH in the Metabolic Switch between Oxidative Phosphorylation and AerobicGlycolysis - Relevance to Cancer

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    Cellular energy in the form of ATP can be produced through oxidative phosphorylation and through glycolysis. Since oxidative phosphorylation requires oxygen and generates ATP more efficiently than glycolysis, it has been assumed for many years that the presence or absence of oxygen determines that cells generate energy through oxidative phosphorylation or through glycolysis. Although cells must activate glycolysis in the absence of oxygen to produce ATP, it is now accepted that they can activate both glycolysis and oxidative phosphorylation in the presence of oxygen. In fact, normal proliferating cells and tumor cells are known to have a high glycolytic activity in the presence of adequate oxygen levels, a phenomenon known as aerobic glycolysis or the Warburg effect. Recent observations have demonstrated that the activation of aerobic glycolysis plays a major role in carcinogenesis and tumor growth. Understanding the mechanisms involved in the metabolic switch between oxidative phosphorylation and aerobic glycolysis may therefore be important for the development of potential preventive and therapeutic interventions. In this article, we discuss the role of the intracellular pH in the metabolic switch between oxidative phosphorylation and aerobic glycolysis. We propose that, in the presence of adequate oxygen levels, the intracellular pH may play a key role in determining the way cells obtain energy, an alkaline pH driving aerobic glycolysis and an acidic pH driving oxidative phosphorylation

    Effects of transcutaneous electric acupoint stimulation on drug use and responses to cue-induced craving: a pilot study

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    Background: Transcutaneous electric acupoint stimulation (TEAS) avoids the use of needles, and instead delivers a mild electric current at traditional acupoints. This technique has been used for treating heroin addiction, but has not been systematically tested for other drugs of abuse. This study aims to investigate the effects of TEAS on drug addiction. Methods: Volunteers who were either cocaine-dependent (n = 9) or cannabis-dependent (n = 11) but were not seeking treatment for their dependence participated in a within-subject, single-blind study. Treatment consisted of twice daily 30-minute sessions of TEAS or sham stimulation for 3.5 days. The active TEAS levels were individually adjusted to produce a distinct twitching response in the fingers, while the sham stimulation involved 2 minutes of stimulation at threshold levels followed by 28 minutes of stimulation below the detection levels. The participants recorded their drug use and drug cravings daily. At 1 hour after the last morning session of TEAS or sham stimulation, a cue-induced craving EEG evaluation was conducted. Event-related P300 potentials (ERPs) were recorded, sorted, and analyzed for specific image types (neutral objects, non-drug-related arousing images, or drug-related images). Results: TEAS treatment did not significantly reduce the drug use or drug cravings, or significantly alter the ERP peak voltage or latency to peak response. However, the TEAS treatment did significantly modulate several self-reported measures of mood and anxiety. Conclusion: The results of this pilot study with a limited sample size suggest that the acupoint stimulation techniques and protocol used in this trial alone do not significantly reduce cravings for or use of cocaine or cannabis. The findings that TEAS modulates mood and anxiety suggest that TEAS could be used as an adjunct in a multimodal therapy program to treat cocaine and cannabis dependence if confirmed in a full randomized controlled clinical trial

    Dietary exposure to parabens and body mass index in an adolescent Spanish population

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    This work was carried out in line with 'GP/EFSA/ENCO/380 2018/03/G04: OBEMIRISK: Knowledge platform for assessing the risk of Bisphenols on gut microbiota and its role in obesogenic phenotype: looking for biomarkers'. This research was also funded by Plan Estatal de I + D + I 2013-2016 and co-funded by FEDER-ISCIII PI17/01758, FEDER-Consejeria de Salud y Familias, Junta de Andalucia PE-0250-2019, FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades/Proyecto P18-RT-4247. All individuals participating in this research signed an informed consent form and the study protocol was approved by the Ethics Com-mittee of the University of Granada.Parabens are alkyl esters of p-hydroxybenzoic acid which are extensively used in cosmetics, pharmaceuticals and foodstuffs due to their antimicrobial properties. The most commonly used parabens are methyl-(MeP), ethyl- (EtP), propyl-(PrP) and butyl-(BuP) paraben. Most human exposure to parabens is achieved through the consumption of food or pharmaceutical products and the use of personal care products. However, studies on dietary parabens exposure and the associated factors are very scarce. The main aim of the present study was to explore factors associated with dietary exposure to parabens in Spanish adolescents according to gender. Dietary data and anthropometric measures were collected from 585 adolescents (53.4% boys) aged 12–16 years. Parabens exposure through diet was assessed using a food frequency questionnaire with food products providing more than 95% of energy and macronutrient intake being included in analysis. Stepwise regression was used to identify the foods that most contributed to parabens intake. Logistic regression was used to evaluate factors predicting higher dietary exposure to parabens. The main contributors to dietary MeP, EtP, PrP and BuP exposure in adolescent boys were eggs (41.9%), canned tuna (46.4%), bakery and baked goods products (57.3%) and pineapple (61.1%). In adolescent girls, the main contributors were apples and pears (35.3%), canned tuna (42.1%), bakery and baked goods products (55.1%) and olives (62.1%). Overweight/obese girls were more likely to belong to the highest tertile of overall parabens intake (odds ratio [OR]: 3.32; 95% confidence interval [95% CI]: 1.21–9.15) and MeP (OR: 3.05; 95% CI: 1.14–8.12) than those with a body mass index lower than 25 kg/m2. These findings suggest a positive association between dietary exposure to parabens and overweight/obesity in adolescent girls.Plan Estatal de I + D + I 2013-2016FEDER-ISCIII PI17/01758FEDER-Consejeria de Salud y FamiliasJunta de Andalucia PE-0250-2019FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades/Proyecto P18-RT-424
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