125 research outputs found

    Trace-metaldynamics in response of increase CO<sub>2</sub> and iron availability in a coastal mesocosm experiment

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    A mesocosm experiment was performed in the Raunefjord (Norway) to study changes in dissolved Cu (dCu) and Fe (dFe), and in the elemental composition of particles during an Emiliania huxleyi dominated bloom. The CO2 treatments consisted of present (LC; 390 ppmV) and predicted levels (HC; 900 ppmV) and iron conditions were created with the addition of the siderophore desferoxamine B (DFB). Our results showed the DFB addition enhanced the solubility of Fe in this fjord environment. Initially, dFe was comparable among treatments but after the addition, the HC and/or +DFB treatments presented higher levels and finally, the only ones maintaining high dFe were the +DFB treatments. Unlike dCu presented indistinguishable levels in all mesocosms over time. Particulate metals were normalised to P and Al to evaluate the relative influence of biotic and abiotic sources. The Fe:P ratios decreased with time and compared to published phytoplankton ratios suggest Fe storage. On the other hand, Fe:Al ratios were relatively closer to the crustal ratios suggesting that the abiotic source was more important for this metal. Trends for other metals will be discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    The effects of ocean acidification and siderophore additions on trace-metal dynamics during an Emiliania Huxleyi- dominated bloom in a coastal mesocosm experiment

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    The combined impacts of high CO2 and changes in trace metal availability on plankton remain largely unknown. A 22 days mesocosm experiment was carried out in the Raunefjord, off Bergen, Norway (June 2012) to investigate the interactive effects of increased CO2 and changes in iron availability in the pelagic community. Twelve mesocosms covered by PAR and UVR transparent lids were used. The CO2 treatments consisted of present (LC; 390 ppmV) and predicted levels for year 2100 (HC; 900 ppmV). On day 7, half of the mesocoms were amended with the siderophore desferoxamine B (DFB) at 70 nM (final concentration). We studied changes in dissolved Cu (dCu) and Fe (dFe), and in the elemental composition of particles. Dissolved Fe and dCu were measured by chemiluminescence flow injection analysis, while particulate metals were determined by high-resolution inductively coupled mass spectrometry. The metals were normalised to P and Al to evaluate the relative influence of biotic and abiotic sources. Samples were taken throughout a bloom of the coccolithophore E. huxleyi. Further details will be discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Una experiencia de formación matemática de maestros usando recursos informáticos

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    En este trabajo describimos el diseño e implementación de un módulo de clases prácticas en el aula de informática, que se ha llevado a cabo en el programa de formación inicial de maestros de educación primaria en el área de matemáticas de la Universidad de Granada. Analizamos la organización de las sesiones prácticas y el tipo de activida- des basadas en la exploración y análisis de una colección de “applets” sobre aritmética, geometría, medida y estadística. Presentamos también algunos resultados de la experien- cia y unas primeras conclusiones sobre las cuestiones de investigación que plantea la incorporación de las nuevas tecnologías en los procesos de enseñanza y aprendizaje de las matemáticas cuando se realiza en este tipo de escenarios presenciales

    Robust Ensemble Classification Methodology for I123-Ioflupane SPECT Images and Multiple Heterogeneous Biomarkers in the Diagnosis of Parkinson’s Disease

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    In last years, several approaches to develop an effective Computer-Aided-Diagnosis (CAD) system for Parkinson’s Disease (PD) have been proposed. Most of these methods have focused almost exclusively on brain images through the use of Machine-Learning algorithms suitable to characterize structural or functional patterns. Those patterns provide enough information about the status and/or the progression at intermediate and advanced stages of Parkinson’s Disease. Nevertheless this information could be insufficient at early stages of the pathology. The Parkinson’s ProgressionMarkers Initiative (PPMI) database includes neurological images along with multiple biomedical tests. This information opens up the possibility of comparing different biomarker classification results. As data come from heterogeneous sources, it is expected that we could include some of these biomarkers in order to obtain new information about the pathology. Based on that idea, this work presents an Ensemble Classification model with Performance Weighting. This proposal has been tested comparing Healthy Control subjects (HC) vs. patients with PD (considering both PD and SWEDD labeled subjects as the same class). This model combines several Support-Vector-Machine (SVM) with linear kernel classifiers for different biomedical group of tests—including CerebroSpinal Fluid (CSF), RNA, and Serum tests—and pre-processed neuroimages features (Voxels-As-Features and a list of definedMorphological Features) fromPPMI database subjects. The proposed methodology makes use of all data sources and selects the most discriminant features (mainly from neuroimages). Using this performance-weighted ensemble classification model, classification results up to 96% were obtained.This work was supported by the MINECO/FEDER under the TEC2015-64718-R project and the Ministry of Economy, Innovation, Science and Employment of the Junta de Andalucía under the Excellence Project P11-TIC-7103

    Solubility of CO2 in three cellulose-dissolving ionic liquids

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    The solubility of CO2 in three cellulose-dissolving ionic liquids (1-ethyl-3-methylimidazolium diethylphosphate, [Emim][DEP], 1-allyl-3-methylimidazolium chloride, [Amim][Cl], and 1-butyl-3-methylimidazolium chloride, [Bmim][Cl]) at temperatures within 298 and 356 K and pressures up to 6.5 MPa was determined using a Van Ness-type apparatus (static isochoric). It was demonstrated that this device can work in isothermal and isoplethal modes, being the latter faster and more precise. Moreover, it was possible to determine CO2 solubilities in metastable liquid [Bmim][Cl]. Experimental data were modeled using the Extended Henry's law correlation and the group contribution equation of state. New parameters for the binary interaction of CO2 with ionic liquid groups were calculated.Fil: Pérez, Eduardo. Universidad de Valladolid; EspañaFil: de Pablo, Laura. Universidad de Valladolid; EspañaFil: Segovia, J. Juan. Universidad de Valladolid; EspañaFil: Moreau, Alejandro. Universidad de Valladolid; EspañaFil: Sánchez, Francisco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Pereda, Selva. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Bermejo, María Dolores. Universidad de Valladolid; Españ

    Diffusive and Arrestedlike Dynamics in Currency Exchange Markets

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    This work studies the symmetry between colloidal dynamics and the dynamics of the Euro–U.S. dollar currency exchange market (EURUSD). We consider the EURUSD price in the time range between 2001 and 2015, where we find significant qualitative symmetry between fluctuation distributions from this market and the ones belonging to colloidal particles in supercooled or arrested states. In particular, we find that models used for arrested physical systems are suitable for describing the EURUSD fluctuation distributions. Whereas the corresponding mean-squared price displacement (MSPD) to the EURUSD is diffusive for all years, when focusing in selected time frames within a day, we find a two-step MSPD when the New York Stock Exchange market closes, comparable to the dynamics in supercooled systems. This is corroborated by looking at the price correlation functions and non-Gaussian parameters and can be described by the theoretical model. We discuss the origin and implications of this analogy

    Wear behaviour of WC plasma sprayed coatings wi th micro and nanostructured powders

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    El objetivo de este trabajo es estudiar el comportamiento a desgaste de distintos recubrimientos de WC sobre acero inoxidable mediante proyección por plasma atmosférico. Se proyectan dos tipos de polvos comerciales con base cobalto (12 %) y níquel (10 %), con el objeto de analizar la influencia de la matriz e incluso del espesor del recubrimiento. Los recubrimientos obtenidos se caracterizan microestructuralmente por microscopía electrónica de barrido y difracción de rayos X. La caracterización tribológica de los recubrimientos se realiza mediante ensayos pin-on-disc contra bolas cerámicas de alúmina (2.400 HV) y nitruro de silicio (1.600 HV), sin lubricación, obteniéndose las tasas de desgaste y la evolución del coeficiente de rozamiento. Las pistas de desgaste y los residuos generados se caracterizaron mediante Microscopía Electrónica de Barrido, MEB. Los resultados muestran diferentes mecanismos de desgaste en cada par de material ensayado en función de la matriz y de la naturaleza de la bola empleada en el ensayo, encontrándose mayores tasas de desgaste con bola de nitruro de silicio. En una segunda fase, se obtienen recubrimientos, con dos polvos base cobalto cuyos tamaños de partícula son micrométrico y nanométrico, respectivamente, con el objetivo de estudiar la influencia del tamaño de partícula inicial sobre las propiedades a desgaste del recubrimiento. Los resultados obtenidos ponen de manifiesto una mayor resistencia al desgaste de los recubrimientos obtenidos con polvos nanoestructurados, bajo condiciones de carga elevadas, mientras que para cargas bajas ambos recubrimientos presentan un comportamiento similar a pesar de las diferencias microestructurales apreciadasThe aim of the present work is the study of wear behaviour of different WC coatings deposited on stainless steel substrate by means of atmospheric plasma spraying (APS). Two types of WC commercial powders, with different metal binder (12% Cobalt and 10% Nickel) have been deposited in order to analyse the influence of the metal matrix and thickness of the coating in tribological properties.The microstructure of the depositions was characterized using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). On the other hand, tribology characterization of the coatings was made by pin-on-disk wear tests against alumina (2400HV) and silicon nitride (1600HV) ceramic balls, without lubrication. Wear rates and friction coefficient evolution have been calculated. Finally, wear tracks and wear debris have been analysed with the help of SEM.The results of each pair of tested materials show different mechanisms of wear related to the nature of the ball that has been used, obtaining higher wear rates with silicone nitride ball..In a second phase of the study, in order to examine the influence of the initial particle size on the wear properties of the coatings, cobalt based coatings have been analysed with different initial particle size (micrometric and nanometric particles).Results show that nanostructured coatings have higher wear resistance than microstrutured ones for high loads. However for low loads, behaviour is similar in spite of the microstructural differences appreciate

    Characterization of dengue cases among patients with an acute illness, Central Department, Paraguay

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    Corresponding authors: Alejandra Rojas, [email protected]; Jesse Waggoner, [email protected]. In 2018, Paraguay experienced a large dengue virus (DENV) outbreak. The primary objective of this study was to characterize dengue cases in the Central Department, where the majority of cases occur, and identify factors associated with DENV infection. Methods. Patients were enrolled from January-May 2018 if they presented with a suspected arboviral illness. Acute-phase specimens (≤8 days after symptom onset) were tested using rRT-PCR, a rapid diagnostic test for DENV nonstructural protein 1 (NS1) and anti-DENV IgM and IgG, and ELISA for IgG against NS1 from Zika virus (ZIKV). Results. A total of 231 patients were enrolled (95.2% adults) at two sites: emergency care and an outpatient clinical site. Patients included 119 (51.5%) dengue cases confirmed by rRT-PCR (n = 115, 96.6%) and/or the detection of NS1 and anti-DENV IgM (n = 4, 3.4%). DENV-1 was the predominant serotype (109/115, 94.8%). Epidemiologically, dengue cases and non-dengue cases were similar, though dengue cases were less likely to reside in a house/apartment or report a previous dengue case. Clinical and laboratory findings associated with dengue included red eyes, absence of sore throat, leucopenia and thrombocytopenia. At an emergency care site, 26% of dengue cases (26/100) required hospitalization. In univariate analysis, hospitalization was associated with increased viral load, anti-DENV IgG, and thrombocytopenia. Among dengue cases that tested positive for IgG against ZIKV NS1, the odds of DENV NS1 detection in the acute phase were decreased 10-fold (OR 0.1, 0.0–0.3). Conclusions. Findings from a predominantly adult population demonstrate clinical and laboratory factors associated with DENV infections and the potential severity of dengue in this group. The combination of viral load and specific IgG antibodies warrant further study as a prognostic to identify patients at risk for severe disease.Consejo Nacional de Ciencia y TecnologíaPrograma Paraguayo para el Desarrollo de la Ciencia y Tecnología. Financiamiento para la vinculación de científicos y tecnólogo

    Assisted Diagnosis of Parkinsonism Based on the Striatal Morphology

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    Parkinsonism is a clinical syndrome characterized by the progressive loss of striatal dopamine. Its diagnosis is usually corroborated by neuroimaging data such as DaTSCAN neuroimages that allow visualizing the possible dopamine deficiency. During the last decade, a number of computer systems have been proposed to automatically analyze DaTSCAN neuroimages, eliminating the subjectivity inherent to the visual examination of the data. In this work, we propose a computer system based on machine learning to separate Parkinsonian patients and control subjects using the size and shape of the striatal region, modeled from DaTSCAN data. First, an algorithm based on adaptative thresholding is used to parcel the striatum. This region is then divided into two according to the brain hemisphere division and characterized with 152 measures, extracted from the volume and its three possible 2-dimensional projections. Afterwards, the Bhattacharyya distance is used to discard the least discriminative measures and, finally, the neuroimage category is estimated by means of a Support Vector Machine classifier. This method was evaluated using a dataset with 189 DaTSCAN neuroimages, obtaining an accuracy rate over 94%. This rate outperforms those obtained by previous approaches that use the intensity of each striatal voxel as a feature.This work was supported by the MINECO/ FEDER under the TEC2015-64718-R project, the Ministry of Economy, Innovation, Science and Employment of the Junta de Andaluc´ıa under the P11-TIC-7103 Excellence Project and the Vicerectorate of Research and Knowledge Transfer of the University of Granada

    Clinical picture, management and risk stratification in patients with cardiogenic shock: does gender matter?

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    Background: Early recognition and risk stratification are crucial in cardiogenic shock (CS). A lower adherence to recommendations has been described in women with cardiovascular diseases. Little information exists about disparities in clinical picture, management and performance of risk stratification tools according to gender in patients with CS. Methods: Data from the multicenter Red-Shock registry were used. All consecutive patients with CS were included. Both CardShock and IABP-SHOCK II risk scores were calculated. The primary end-point was in-hospital mortality. The discriminative ability of both scores according to gender was assessed by binary logistic regression, calculating Receiver operating characteristic (ROC) curves and the corresponding area under the curve (AUC). Results: A total of 793 patients were included, of whom 222 (28%) were female. Women were significantly older and had a lower proportion of chronic obstructive pulmonary disease and prior myocardial infarction. CS was less often related to acute coronary syndromes (ACS) in women. The use of vasoactive drugs, renal replacement therapy, invasive ventilation, therapeutic hypothermia and mechanical circulatory support was similar between both groups. In-hospital mortality was 346/793 (43.6%). Mortality was not significantly different according to gender (p = 0.194). Cardshock risk score showed a good ability for predicting in-hospital mortality both in man (AUC 0.69) and women (AUC 0.735). Likewise, the IABP-II successfully predicted in-hospital mortality in both groups (man: AUC 0.693; women: AUC 0.722). Conclusions: No significant differences were observed regarding management and in-hospital mortality according to gender. Both the CardShock and IABP-II risk scores depicted a good ability for predicting mortality also in women with CS
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