1,920 research outputs found

    Characterization of non-intentional emissions from distributed energy resources up to 500 kHz: A case study in Spain

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    Narrow Band Power Line Communications (NB-PLC) systems are currently used for smart metering and power quality monitoring as a part of the Smart Grid (SG) concept. However, non-intentional emissions generated by the devices connected to the grid may sometimes disturb the communications and isolate metering equipment. Though some research works have been recently developed to characterize these emissions, most of them have been limited to frequencies below 150 kHz and they are mainly focused on in-house electronic appliances and lightning devices. As NB-PLC can also be allocated in higher frequencies up to 500 kHz, there is still a lack of analysis in this frequency range, especially for emissions from Distributed Energy Resources (DERs). The identification and characterization of the emissions is essential to develop solutions that avoid a negative impact on the proper performance of NB-PLC. In this work, the non-intentional emissions of different types of DERs composing a representative microgrid have been measured in the 35–500 kHz frequency range and analyzed both in time and frequency domains. Different working conditions and coupling and commutation procedures to mains are considered in the analysis. Results are then compared to the limits recommended by regulatory bodies for spurious emissions from communication systems in this frequency band, as no specific limits for DERs have been established. Field measurements show clear differences in the characteristics of non-intentional emissions for different devices, working conditions and coupling procedures and for frequencies below and above 150 kHz. Results of this study demonstrate that a further characterization of the potential emissions from the different types of DERs connected to the grid is required in order to guarantee current and future applications based on NB-PLC.This work has been financially supported in part by the Basque Government (Elkartek program)

    The impact of geographical factors on churn prediction: an application to an insurance company in Madrid's urban area

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    Geography has previously been noted as a decisive factor in business literature. This paper provides evidence of the significant role geography plays in customer lapse behaviour in an urban environment. This novel approach is based on the idea that the customers who cancel all policies and leave the company are not randomly distributed; rather, a mimetic performance of close individuals is noted. The physical proximity of the customer to the geographical focus (strategical centre, as insurance offices) and the interaction with nearby customer are spatial factors that increase (or decrease) the probability of churning. An empirical analysis using more than 7000 spatially georeferenced offline customers of a Spanish insurance company in the urban area of Madrid (Spain) demonstrated that the customer''s proximity to offices of such insurance company under study decreases the probability of churning, whereas high lapse risk was detected in customers in the surroundings of the company''s competitor branches. In addition, we identified spatial autocorrelation in churn probability, thus demonstrating that the probability of churn of a customer increases if nearby customers churn

    Automated blood culture systems

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    This review compares automated systems of blood culture for the detection of positive bottles, excluding mycobacteria. The performance of different systems is influenced by several key variables, including volume of the blood sample, the use of resins, shaking to increase the recovery of aerobic microorganisms, duration of incubation and final subculture. The Bactec, BacT/Alert, BioArgos and ESP systems require further study and technical improvement. There is no single ideal system of blood culture, and combinations of two or more methods are likely to provide the best results

    Using plant-based preparations to protect common bean against halo blight disease: the potential of nettle to trigger the immune system

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    Halo blight disease of beans (Phaseolus vulgaris L.), caused by the bacterium Pseudomonas syringae pv. phaseolicola (Pph), is responsible for severe losses in crop production worldwide. As the current agronomic techniques used are not effective, it is necessary to search for new ones which may prevent disease in common bean. In this study, we challenged four plant-based preparations (PBPs), with no other agronomic uses, as they come from industrial waste (grapevine pomace (R-G) and hop residue (R-H)) or wild plants (Urtica dioica (U) and Equisetum sp. (E)), to be used as immune defense elicitors against Pph in common bean. After studying their inhibitory effect against Pph growth by bioassays, the two most effective PBPs (R-G and U) were applied in common bean plants. By measuring the total H2O2, lipid peroxidation, and antioxidant enzymatic activities, as well as the expression of six defense-related genes-PR1, WRKY33, MAPKK, RIN4, and PAL1-, it was observed that U-PBP application involved a signaling redox process and the overexpression of all genes, mostly PR1. First infection trials in vitro suggested that the application of U-PBP involved protection against Pph. The elicitation of bean defense with U-PBP involved a decrease in some yield parameters, but without affecting the final production. All these findings suggest a future use of U-PBP to diminish halo blight disease

    Hypocretin/Orexin Neuropeptides: Participation in the Control of Sleep-Wakefulness Cycle and Energy Homeostasis

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    Hypocretins or orexins (Hcrt/Orx) are hypothalamic neuropeptides that are synthesized by neurons located mainly in the perifornical area of the posterolateral hypothalamus. These hypothalamic neurons are the origin of an extensive and divergent projection system innervating numerous structures of the central nervous system. In recent years it has become clear that these neuropeptides are involved in the regulation of many organic functions, such as feeding, thermoregulation and neuroendocrine and cardiovascular control, as well as in the control of the sleep-wakefulness cycle. In this respect, Hcrt/Orx activate two subtypes of G protein-coupled receptors (Hcrt/Orx1R and Hcrt/Orx2R) that show a partly segregated and prominent distribution in neural structures involved in sleep-wakefulness regulation. Wakefulness-enhancing and/or sleep-suppressing actions of Hcrt/Orx have been reported in specific areas of the brainstem. Moreover, presently there are animal models of human narcolepsy consisting in modifications of Hcrt/Orx receptors or absence of these peptides. This strongly suggests that narcolepsy is the direct consequence of a hypofunction of the Hcrt/Orx system, which is most likely due to Hcrt/Orx neurons degeneration

    Few-body decay and recombination in nuclear astrophysics

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    Three-body continuum problems are investigated for light nuclei of astrophysical relevance. We focus on three-body decays of resonances or recombination via resonances or the continuum background. The concepts of widths, decay mechanisms and dynamic evolution are discussed. We also discuss results for the triple α\alpha decay in connection with 2+2^+ resonances and density and temperature dependence rates of recombination into light nuclei from α\alpha-particles and neutrons.Comment: 9 pages, 8 figures. Proceedings of the 21st European Few Body Conference held in Salamanca (Spain) in August-September 201

    Resveratrol augments ER stress and the cytotoxic effects of glycolytic inhibition in neuroblastoma by downregulating Akt in a mechanism independent of SIRT1

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    Cancer cells typically display increased rates of aerobic glycolysis that are correlated with tumor aggressiveness and a poor prognosis. Targeting the glycolytic pathway has emerged as an attractive therapeutic route mainly because it should spare normal cells. Here, we evaluate the effects of combining the inhibition of glycolysis with application of the polyphenolic compound resveratrol (RSV) in neuroblastoma (NB) cancer cell lines. Inhibiting glycolysis with 2-deoxy-D-glucose (2-DG) significantly reduced NB cell viability and was associated with increased endoplasmic reticulum (ER) stress and Akt activity. Administration of 2-DG increased the expression of the ER molecular chaperones GRP78 and GRP94, the prodeath protein C/EBP homology protein (CHOP) and the phosphorylation of Akt at S473, T450 and T308. Combined treatment with both RSV and 2-DG reduced GRP78, GRP94 and Akt phosphorylation but increased CHOP and NB cell death when compared with the administration of 2-DG alone. The selective inhibition of Akt activity also decreased 2-DG-induced GRP78 and GRP94 expression and increased CHOP expression, suggesting that Akt can modulate ER stress. Protein phosphatase 1 alpha (PP1 alpha) was activated by RSV, as indicated by a reduction in PP1 alpha phosphorylation at T320. Pretreatment of cells with tautomycin, a selective PP1 alpha inhibitor, prevented the RSV-mediated decrease in Akt phosphorylation, suggesting that RSV enhances 2-DG-induced cell death by activating PP1 and downregulating Akt. The RSV-mediated inhibition of Akt in the presence of 2-DG was not prevented by the selective inhibition of SIRT1, a known target of RSV, indicating that the effects of RSV on this pathway are independent of SIRT1. We propose that RSV inhibits Akt activity by increasing PP1 alpha activity, thereby potentiating 2-DG-induced ER stress and NB cell death

    Analysis of antenal sensilla patterns of Rhodnius prolixus from Colombia and Venezuela

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    Antennal sensilla patterns were used to analyze population variation of domestic Rhodnius prolixus from six departments and states representing three biogeographical regions of Colombia and Venezuela. Discriminant analysis of the patterns of mechanoreceptors and of three types of chemoreceptors on the pedicel and flagellar segments showed clear differentiation between R. prolixus populations east and west of the Andean Cordillera. The distribution of thick and thin-walled trichoids on the second flagellar segment also showed correlation with latitude, but this was not seen in the patterns of other sensilla. The results of the sensilla patterns appear to be reflecting biogeographic features or population isolation rather than characters associated with different habitats and lend support to the idea that domestic R. prolixus originated in the eastern region of the Andes.Fil: Esteban, Lyda. Universidad Industrial de Santander; ColombiaFil: Angulo, Víctor Manuel. Universidad Industrial de Santander; ColombiaFil: Dora Feliciangeli, M.. Universidad de Carabobo; VenezuelaFil: Catala, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentin

    Optical and tribo-mechanical characterization in metal-ceramic multilayers coatings

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    Laboratory scale studies of tribological properties of nitride coatings are useful in predicting their protective wear behavior in cutting toolsfor industrial-scale applications. The main aim of this research is to determine optical and tribo-mechanical properties in multilayer coatingsof metal-ceramic assigned as coatings A and B. These coatings were deposited by DC magnetron sputtering on carbon steel AISI 1060using buffer adhesion layers of W, Ti/W/WN and TiN/TiN respectively. For to determine molecules, interactions of materials were analyzedthrough of Raman and FTR spectroscopies. The nanohardness, tribological and adhesion behavior were studied by nanoindentation, pinon disk and a tribometer. The hardness and behavior tribological, were obtained by Nano-indentation, pin on disk, and scratch test using atribometer. FTIR and Raman analysis shown the formation of Ti metallic ion and WO3mainly in both coatings. The hardness of coatingsshown a slight improvement compared with the substrate. However, for industrial applications this property should be increase. The behaviorof COF does not present improvement. The mass loss and wear rate were high significantly due to the formation of cracks on surface coatings.Scratch analysis, it found three wear mechanics determined by the presence of irregular borders with sharp shadow, semicircle detachmentin coatings and coatings detachment in the central track as the load increase

    The Emotional Competence Assessment Questionnaire (ECAQ) for Children Aged from 3 to 5 Years : Validity and Reliability Evidence

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    In order to assess emotional competence in children, it is necessary to have psychometrically sound measures. To the best of our knowledge, there is no available tool to assess emotional competence in children from 3 to 5 years old that assesses the five emotional competences of the Bisquerra model and can be easily and quickly answered in the school environment. The objective of this study is to develop a measure, the Emotional Competence Assessment Questionnaire (ECAQ), and to provide evidence of its psychometric quality. Qualitative evidence was obtained from a systematic review, from two expert committees and from five discussion groups. On the other hand, quantitative validity and reliability evidence was obtained from a sample of 1088 students and other smaller subsamples. The results suggest that the ECAQ is a short and easy-to-use tool, easily understood by administrators. The quantitative results confirm a general factor of emotional competence adjusted for three specific factors. This factor has excellent internal consistency and test-retest reliability. The ECAQ has therefore been shown to be a promising tool for assessing emotional competence in children between 3 and 5 years of age
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