788 research outputs found
Volatility transmission along the money market yield curve
In this paper we look to model the volatility of money market interest rates -and the transmission of volatility- along the money market yield curve in four countries: the UK, Germany, France and Spain. We use a conditional variance specification which is based on Nelson's Exponential ARCH. We find a significant volatility transmission effect from overnight to longer term money markets for France, Spain and the UK. We also find that, in our small cross section of countries, those with lower (higher) reserve requirements tend to have higher (lower) interbank interest rate volatility. However, reserve requirements generate a perverse seasonal effect: at the end of the maintenance period, both the level of the overnight interest rate volatility and the magnitude of the transmission effect to the rest of the yield curve are higher. References.(jah)(agh)(frl)(jha
Chemical and structural investigation of the role of both Mn and Mn oxide in the formation of manganese silicate barrier layers on SiO2
In this study, Mn silicate (MnSiO3) barrier layers were formed on thermally grown SiO2 using both
metallic Mn and oxidized Mn films, in order to investigate the role of oxygen in determining the
extent of the interaction between the deposited Mn and the SiO2 substrate. Using x-ray photoelectron
spectroscopy, it has been shown that a metallic Mn film with an approximate thickness of 1 nm
cannot be fully converted to Mn silicate following vacuum annealing to 500 C. Transmission
electron microscopy (TEM) analysis suggests the maximum MnSiO3 layer thickness obtainable using
metallic Mn is 1.7 nm. In contrast, a 1 nm partially oxidized Mn film can be fully converted to
Mn silicate following thermal annealing to 400 C, forming a MnSiO3 layer with a measured
thickness of 2.6 nm. TEM analysis also clearly shows that MnSiO3 growth results in a corresponding
reduction in the SiO2 layer thickness. It has also been shown that a fully oxidized Mn oxide thin film
can be converted to Mn silicate, in the absence of metallic Mn. Based on these results it is suggested
that the presence of Mn oxide species at the Mn/SiO2 interface facilitates the conversion of SiO2 to
MnSiO3, in agreement with previously published studies.Fundación de Ciencias de Irlanda 08/IN.1/I205
Hipertrigliceridemia y preeclampsia: papel fisiopatológico y evidencia actual
ResumenLa preclampsia es una patología con alta incidencia morbimortalidad materno-fetal, especialmente en países en vía de desarrollo. Aunque no se conoce con certeza su etiología, estudios realizados hasta el momento señalan a la disfunción endotelial como factor critico en la génesis, desarrollo y complicaciones de esta enfermedad. Entre los factores más estudiados se encuentran el fenómeno de peroxidación lipídica, que asu vez puede ser consecuencia de un aumento en los lipidos circulares de la gestante, en particular los trialcilgliceroles. El presente articulo hace una descripción del posible papel de los lípidos en la fisiopatología de la preeclampsia y la evidencia actual aserca del fenómeno de hipertrigliceridemia en las mujeres preeclampticas.[Martínez MP, Lozano JG. Hipertrigliceridemia y preeclampsia: papel fisiopatológico y evidencia actual. MedUNAB 2005; 8:118-123].Palabras clave: preeclampsia, disfunción endotelial, peroxidación lipídica, hipertrigliceridemia
Strain Relief Analysis of InN Quantum Dots Grown on GaN
We present a study by transmission electron microscopy (TEM) of the strain state of individual InN quantum dots (QDs) grown on GaN substrates. Moiré fringe and high resolution TEM analyses showed that the QDs are almost fully relaxed due to the generation of a 60° misfit dislocation network at the InN/GaN interface. By applying the Geometric Phase Algorithm to plan-view high-resolution micrographs, we show that this network consists of three essentially non-interacting sets of misfit dislocations lying along the directions. Close to the edge of the QD, the dislocations curve to meet the surface and form a network of threading dislocations surrounding the system
Uso de tecnologías avanzadas de inteligencia artificial en aplicaciones agrícolas y botánicas
Este artículo presenta el uso de tecnologías avanzadas de inteligencia artificial en aplicaciones agrícolas y botánicas, desarrolladas por los semilleros de investigación Lún y MECAUTRONIC del grupo de investigación D+TEC de la Universidad de Ibagué. La aplicación de la inteligencia artificial en la agricultura y el cuidado del medio ambiente tiene un gran campo de acción destacando el uso de técnicas como el procesamiento de imágenes, el aprendizaje de máquinas y la interacción con el entorno
Simulating the Gradually Deteriorating Performance of an RTG
Degra (now in version 3) is a computer program that simulates the performance of a radioisotope thermoelectric generator (RTG) over its lifetime. Degra is provided with a graphical user interface that is used to edit input parameters that describe the initial state of the RTG and the time-varying loads and environment to which it will be exposed. Performance is computed by modeling the flows of heat from the radioactive source and through the thermocouples, also allowing for losses, to determine the temperature drop across the thermocouples. This temperature drop is used to determine the open-circuit voltage, electrical resistance, and thermal conductance of the thermocouples. Output power can then be computed by relating the open-circuit voltage and the electrical resistance of the thermocouples to a specified time-varying load voltage. Degra accounts for the gradual deterioration of performance attributable primarily to decay of the radioactive source and secondarily to gradual deterioration of the thermoelectric material. To provide guidance to an RTG designer, given a minimum of input, Degra computes the dimensions, masses, and thermal conductances of important internal structures as well as the overall external dimensions and total mass
X-ray nanoimaging of Nd3+ optically active ions embedded in Sr0.5Ba0.5Nb2O6 nanocrystals
[EN] The spatial distribution of Sr0.5Ba0.5Nb2O6 nanocrystals is analyzed in a borate-based glass-ceramic by a synchrotron hard X-ray nanoimaging tool. Based on X-ray excited optical luminescence, we examined 2D projections of the Nd3+ optically active ions in the Sr0.5Ba0.5Nb2O6 nanocrystals, as well as in the glassy phase where they are embedded. Our findings reveal areas of agglomerations and/or clusters of nanocrystals ascribed to the diffusion coefficients of their constituent elements. They are characterized by high Nd3+ concentrations that may act as heterogeneous agents for the nucleation and growth of these nanocrystals. (C) 2017 Optical Society of AmericaMINECO, EU-FEDER and CSIC through the projects MAT2013-46649-C4-4-P, MAT201571070-REDC, MAT2016-75586-C4-2-P, MAT2016-75586-C4-4-P, 201550I021 and 201660I001, respectively. JAS acknowledges the Spanish Program Ramón y Cajal for his fellowship. We also thank the ESRF for the beam time allocated and experimental facilities.Martínez-Criado, G.; Alén, B.; Sans-Tresserras, JÁ.; Lozano-Gorrín, A.; Haro-González, P.; Martin, I.; Lavin, V. (2017). X-ray nanoimaging of Nd3+ optically active ions embedded in Sr0.5Ba0.5Nb2O6 nanocrystals. Optical Materials Express. 7(7):2424-2431. https://doi.org/10.1364/OME.7.002424S2424243177Nagata, K., Yamamoto, Y., Igarashi, H., & Okazaki, K. (1981). Properties of the hot-pressed strontium barium niobate ceramics. Ferroelectrics, 38(1), 853-856. doi:10.1080/00150198108209556Imai, T., Yagi, S., Yamazaki, H., & Ono, M. (1999). Effects of Heat Treatment on Photorefractive Sensitivity of Ce- and Eu-Doped Strontium Barium Niobate. Japanese Journal of Applied Physics, 38(Part 1, No. 4A), 1984-1988. doi:10.1143/jjap.38.1984Volk, T., Isakov, D., Salobutin, V., Ivleva, L., Lykov, P., Ramzaev, V., & Wöhlecke, M. (2004). Effects of Ni doping on properties of strontium–barium–niobate crystals. Solid State Communications, 130(3-4), 223-226. doi:10.1016/j.ssc.2004.01.039Romero, J. J., Andreeta, M. R. B., Andreeta, E. R. M., Bausá, L. E., Hernandes, A. C., & García Solé, J. (2004). Growth and characterization of Nd-doped SBN single crystal fibers. Applied Physics A, 78(7), 1037-1042. doi:10.1007/s00339-003-2151-3Chayapiwut, N., Honma, T., Benino, Y., Fujiwara, T., & Komatsu, T. (2005). Synthesis of Sm3+-doped strontium barium niobate crystals in glass by samarium atom heat processing. Journal of Solid State Chemistry, 178(11), 3507-3513. doi:10.1016/j.jssc.2005.09.002Haro-González, P., Martín, I. R., Martín, L. L., León-Luis, S. F., Pérez-Rodríguez, C., & Lavín, V. (2011). Characterization of Er3+ and Nd3+ doped Strontium Barium Niobate glass ceramic as temperature sensors. Optical Materials, 33(5), 742-745. doi:10.1016/j.optmat.2010.11.026Ivleva, L. I., Volk, T. R., Isakov, D. V., Gladkii, V. V., Polozkov, N. M., & Lykov, P. A. (2002). Growth and ferroelectric properties of Nd-doped strontium–barium niobate crystals. Journal of Crystal Growth, 237-239, 700-702. doi:10.1016/s0022-0248(01)01997-2Marcinkevičius, A., Juodkazis, S., Watanabe, M., Miwa, M., Matsuo, S., Misawa, H., & Nishii, J. (2001). Femtosecond laser-assisted three-dimensional microfabrication in silica. Optics Letters, 26(5), 277. doi:10.1364/ol.26.000277Sato, R., Benino, Y., Fujiwara, T., & Komatsu, T. (2001). YAG laser-induced crystalline dot patterning in samarium tellurite glasses. Journal of Non-Crystalline Solids, 289(1-3), 228-232. doi:10.1016/s0022-3093(01)00736-0Haro-González, P., Martín, L. L., González-Pérez, S., & Martín, I. R. (2010). Formation of Nd3+ doped Strontium Barium Niobate nanocrystals by two different methods. Optical Materials, 32(10), 1389-1392. doi:10.1016/j.optmat.2010.03.011Haro-González, P., Martín, I. R., & Creus, A. H. (2010). Nanocrystals distribution inside the writing lines in a glass matrix using Argon laser irradiation. Optics Express, 18(2), 582. doi:10.1364/oe.18.000582Haro-González, P., Martín, I. R., Arbelo-Jorge, E., González-Pérez, S., Cáceres, J. M., & Núñez, P. (2008). Laser irradiation in Nd3+ doped strontium barium niobate glass. Journal of Applied Physics, 104(1), 013112. doi:10.1063/1.2952011Kowalska, D., Haro-González, P., Martín, I. R., & Cáceres, J. M. (2010). Analysis of the optical properties of Er3+-doped strontium barium niobate nanocrystals using time-resolved laser spectroscopy. Applied Physics A, 99(4), 771-776. doi:10.1007/s00339-010-5716-yPellicer-Porres, J., Segura, A., Martínez-Criado, G., Rodríguez-Mendoza, U. R., & Lavín, V. (2012). Formation of nanostructures in Eu3+doped glass–ceramics: an XAS study. Journal of Physics: Condensed Matter, 25(2), 025303. doi:10.1088/0953-8984/25/2/025303Martínez-Criado, G., Alén, B., Sans, J. A., Homs, A., Kieffer, I., Tucoulou, R., … Yi, G. (2012). Spatially resolved X-ray excited optical luminescence. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 284, 36-39. doi:10.1016/j.nimb.2011.08.013Martínez-Criado, G., Sans, J. A., Segura-Ruiz, J., Tucoulou, R., Solé, A. V., Homs, A., … Alén, B. (2011). X-ray excited optical luminescence imaging of InGaN nano-LEDs. physica status solidi (c), 9(3-4), 628-630. doi:10.1002/pssc.201100430Villanova, J., Segura-Ruiz, J., Lafford, T., & Martinez-Criado, G. (2012). Synchrotron microanalysis techniques applied to potential photovoltaic materials. Journal of Synchrotron Radiation, 19(4), 521-524. doi:10.1107/s0909049512021383Smith, J., Akbari-Sharbaf, A., Ward, M. J., Murphy, M. W., Fanchini, G., & Kong Sham, T. (2013). Luminescence properties of defects in nanocrystalline ZnO. Journal of Applied Physics, 113(9), 093104. doi:10.1063/1.4794001Armelao, L., Heigl, F., Jürgensen, A., Blyth, R. I. R., Regier, T., Zhou, X.-T., & Sham, T. K. (2007). X-ray Excited Optical Luminescence Studies of ZnO and Eu-Doped ZnO Nanostructures. The Journal of Physical Chemistry C, 111(28), 10194-10200. doi:10.1021/jp071379fMartínez-Criado, G., Villanova, J., Tucoulou, R., Salomon, D., Suuronen, J.-P., Labouré, S., … Morse, J. (2016). ID16B: a hard X-ray nanoprobe beamline at the ESRF for nano-analysis. Journal of Synchrotron Radiation, 23(1), 344-352. doi:10.1107/s1600577515019839Jamieson, P. B., Abrahams, S. C., & Bernstein, J. L. (1968). Ferroelectric Tungsten Bronze‐Type Crystal Structures. I. Barium Strontium Niobate Ba0.27Sr0.75Nb2O5.78. The Journal of Chemical Physics, 48(11), 5048-5057. doi:10.1063/1.1668176Haro-González, P., Martín, I. R., & Hernández Creus, A. (2011). Nanocrystals formation on Ho3+ doped strontium barium niobate glass. Journal of Luminescence, 131(4), 657-661. doi:10.1016/j.jlumin.2010.11.011Lavı́n, V., Rodrı́guez-Mendoza, U. R., Martı́n, I. R., & Rodrı́guez, V. D. (2003). Optical spectroscopy analysis of the Eu3+ ions local structure in calcium diborate glasses. Journal of Non-Crystalline Solids, 319(1-2), 200-216. doi:10.1016/s0022-3093(02)01914-2Chernaya, T. S., Volk, T. R., Verin, I. A., Ivleva, L. I., & Simonov, V. I. (2002). Atomic structure of (Sr0.50Ba0.50)Nb2O6 single crystals in the series of (SrxBa1 − x )Nb2O6 compounds. Crystallography Reports, 47(2), 213-216. doi:10.1134/1.1466494Erbil, A., Cargill III, G. S., Frahm, R., & Boehme, R. F. (1988). Total-electron-yield current measurements for near-surface extended x-ray-absorption fine structure. Physical Review B, 37(5), 2450-2464. doi:10.1103/physrevb.37.2450Solé, V. A., Papillon, E., Cotte, M., Walter, P., & Susini, J. (2007). A multiplatform code for the analysis of energy-dispersive X-ray fluorescence spectra. Spectrochimica Acta Part B: Atomic Spectroscopy, 62(1), 63-68. doi:10.1016/j.sab.2006.12.002Martínez-Criado, G., Homs, A., Alén, B., Sans, J. A., Segura-Ruiz, J., Molina-Sánchez, A., … Yi, G.-C. (2012). Probing Quantum Confinement within Single Core–Multishell Nanowires. Nano Letters, 12(11), 5829-5834. doi:10.1021/nl303178uMartínez-Criado, G., Segura-Ruiz, J., Alén, B., Eymery, J., Rogalev, A., Tucoulou, R., & Homs, A. (2014). Exploring Single Semiconductor Nanowires with a Multimodal Hard X-ray Nanoprobe. Advanced Materials, 26(46), 7873-7879. doi:10.1002/adma.201304345Shyu, J.-J., & Wang, J.-R. (2000). Crystallization and Dielectric Properties of SrO-BaO-Nb2O5-SiO2Tungsten-Bronze Glass-Ceramics. Journal of the American Ceramic Society, 83(12), 3135-3140. doi:10.1111/j.1151-2916.2000.tb01694.
Metodología para la estandarización del modelo normativo en centrales eléctricas de Norte de Santander – Grupo EPM.
This document defines the methodology for standardizing the normative management model of CENS - Grupo EPM. Todevelop this methodology, a diagnosis of the current model was conducted using a structured questionnaire that determined the extent of thestaff´s knowledge of policy management. Applied normative elements and implemented management systems were also analyzed, identifyingthose requirements that can be fulfilled through regulatory means. Finally, the current regulatory model of CENS was compared with themodel of other electrical companies in Colombia and Mexico, highlighting flaws that require adaptations to the current regulatory model.Those adaptations will contribute to the successful execution of the processes and will help to meet the requirements of the managementsystems, all of which aim to strengthen the rules regarding the four regulatory elements discussed in Bussines Process ManagementEl presente documento define la metodología para la estandarización del modelo normativo de CENS - Grupo EPM, para suconstrucción se realizó un diagnóstico del modelo actual aplicando un cuestionario estructurado que determinó el grado de conocimiento delpersonal sobre la Gestión Normativa, así mismo, se analizaron los elementos normativos aplicados y los sistemas de gestión implementados,identificando requisitos a los que pueda darse cumplimiento a través de elementos normativos, finalmente se comparó el modelo normativoactual de CENS con el modelo de otras empresas del sector eléctrico en Colombia y en México, evidenciando falencias que requerían adecuarel modelo normativo actual a fin que se convierta en un aporte para la operacionalización de los procesos y permita cumplir los requisitosestablecidos en los sistemas de gestión, por lo que se propone consolidar las normas en cuatro elementos normativos con enfoque BussinesProcess Managment
Diagnostic yield of electromagnetic navigation bronchoscopy is highly dependent on the presence of a Bronchus sign on CT imaging: results from a prospective study
Electromagnetic navigation bronchoscopy (ENB) has been developed as a
novel ancillary tool for the bronchoscopic diagnosis of pulmonary nodules.
Despite successful navigation in 90% of patients, ENB diagnostic yield does not
generally exceed 70%. We sought to determine whether the presence of a bronchus
sign on CT imaging conditions diagnostic yield of ENB and might account for the
discrepancy between successful navigation and diagnostic yield. METHODS: We
conducted a prospective, single-center study of ENB in 51 consecutive patients
with pulmonary nodules. ENB was chosen as the least invasive diagnostic technique
in patients with a high surgical risk, suspected metastatic disease, or
advanced-stage disease, or in those who demanded a preoperative diagnosis prior
to undergoing curative resection. We studied patient and technical variables that
might condition diagnostic yield, including size, cause, location, distance to
the pleural surface, and fluorodeoxyglucose uptake of a given nodule; the
presence of a bronchus sign on CT imaging; registration point divergence; and the
minimum distance from the tip of the locatable guide to the nodule measured
during the procedure. RESULTS: The diagnostic yield of ENB was 67% (34/51). The
sensitivity and specificity of ENB for malignancy in this study were 71% and
100%, respectively. ENB was diagnostic in 79% (30/38) patients with a bronchus
sign on CT imaging but only in 4/13 (31%) with no discernible bronchus sign.
Univariate analysis identified the bronchus sign (P = .005) and nodule size (P =
.04) as statistically significant variables conditioning yield, but on
multivariate analysis, only the bronchus sign remained significant (OR, 7.6; 95%
CI, 1.8-31.7). No procedure-related complications were observed. CONCLUSIONS: ENB
diagnostic yield is highly dependent on the presence of a bronchus sign on CT
imaging
Educación y cooperación para el desarrollo mediante estándares universales de accesibilidad
II FORO «IBEROAMÉRICA EN LA ESCENA ECONÓMICA INTERNACIONAL: INVERSIONES Y EDUCACIÓN PARA EL DESARROLLO». UNIVERSIDAD REY JUAN CARLOS, MADRID (ESPAÑA), 14 DE DICIEMBRE DE 200
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