1,403 research outputs found

    Reactivity of vinyl and alkynyl zirconium complexes with the di-ansa-[1,1′,2,2′-bis(dimethylsilanediyl) dicyclopentadienyl] ligand

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    Vinylation of the chloro–ethyl and dichloro zirconium complexes [Zr(CpSi2Cp)ClX] (CpSi2Cp=1,1′,2,2′-(SiMe2)2(η5-C5H3)2; X=Et, Cl) with one or two equivalents of Mg(CH=CH2)Cl gave the new zirconacyclopentane [Zr(CpSi2Cp){η2-CH2-(CH2)2-CH2}] and (η4-butadiene)zirconium [Zr(CpSi2Cp){η4-(butadiene)}] complexes, respectively. Addition of a toluene solution of PhC=CPh to the zirconacyclopentane compound afforded the zirconacyclopentadiene derivative [Zr(CpSi2Cp){η2-(CPh=CPh-CPh=CPh)}]. Reaction of the chloro–ethyl zirconium complex with LiC=CPh afforded the alkynyl compound [Zr(CpSi2Cp)Et(C=CPh)] which reacted with CN(2,6-Me2C6H3) to give the insertion product [Zr(CpSi2Cp)(C=CPh){η2-C(Et)=N(2,6-Me2C6H3)}]. Reactions of the chloro–ethyl [Zr(CpSi2Cp)EtCl] and alkynyl-ethyl [Zr(CpSi2Cp)Et(C=CPh)] complexes with the Lewis acid B(C6F5)3 yielding various cationic species have been monitored by 1H-NMR spectroscopy. The new complexes reported and their intermediates have been identified by IR and 1H- and 13C-NMR spectroscopy

    Planteamiento metodológico para lograr la eficiencia hídrica sustentable. Estudio de caso: unidad habitacional Tepic, Nayarit

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    El presente trabajo consiste en un estudio acerca de la problemática que enfrentan los conjuntos habitacionales en Tepic Nayarit, para abastecer la creciente demanda de la población. Se parte de cuatro aspectos fundamentales que un sistema de agua potable debe cumplir, de acuerdo a la Comisión Nacional del Agua. Referido a un estudio de caso, en donde se hizo un análisis del contexto en relación con el suministro y presión del agua, análisis del usuario en relación con el consumo de agua, que incluye un monitoreo de gasto actual y otro con dispositivos ahorradores. Al final se establecen escenarios para mejorar el abastecimiento continuo de agua, y para conocer el efecto que tiene la implementación de dispositivos ahorradores. La eficiencia hídrica promovida en estas viviendas ayudará a garantizar el abastecimiento continuo, promover el uso adecuado y consiente del agua, fomentar hábitos de consumo responsable y ayudar a preservar los mantos acuíferos de la ciudad.ITESO, A.C

    Predictive Model for Preeclampsia Combining sFlt-1, PlGF, NT-proBNP, and Uric Acid as Biomarkers

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    Angiogenic factors; Preeclampsia; Uric acidFactores angiogénicos; Preeclampsia; Ácido úricoFactors angiogènics; Preeclàmpsia; Àcid úricN-terminal pro-brain natriuretic peptide (NT-proBNP) and uric acid are elevated in pregnancies with preeclampsia (PE). Short-term prediction of PE using angiogenic factors has many false-positive results. Our objective was to validate a machine-learning model (MLM) to predict PE in patients with clinical suspicion, and evaluate if the model performed better than the sFlt-1/PlGF ratio alone. A multicentric cohort study of pregnancies with suspected PE between 24+0 and 36+6 weeks was used. The MLM included six predictors: gestational age, chronic hypertension, sFlt-1, PlGF, NT-proBNP, and uric acid. A total of 936 serum samples from 597 women were included. The PPV of the MLM for PE following 6 weeks was 83.1% (95% CI 78.5-88.2) compared to 72.8% (95% CI 67.4-78.4) for the sFlt-1/PlGF ratio. The specificity of the model was better; 94.9% vs. 91%, respectively. The AUC was significantly improved compared to the ratio alone [0.941 (95% CI 0.926-0.956) vs. 0.901 (95% CI 0.880-0.921), p < 0.05]. For prediction of preterm PE within 1 week, the AUC of the MLM was 0.954 (95% CI 0.937-0.968); significantly greater than the ratio alone [0.914 (95% CI 0.890-0.934), p < 0.01]. To conclude, an MLM combining the sFlt-1/PlGF ratio, NT-proBNP, and uric acid performs better to predict preterm PE compared to the sFlt-1/PlGF ratio alone, potentially increasing clinical precision.This work was supported by public funds obtained in competitive calls with peer review (grant PI19/00702), Insituto de Salud Carlos III, Spanish Ministry of Health, by the Maternal and Child Health and Development Network (SAMID, RD16/0022/0015), Instituto de Salud Carlos III, Madrid, Spain, the Spanish Clinical Research and Clinical Trials Platform, SCReN (Spanish Clinical Research Network), funded by the ISCIII-General Subdirectorate for Evaluation and Promotion of Research, through project PT13/0002/0028, integrated in the 2013–2016 R + D + I State Plan and co-financed by and the European Regional Development Fund (FEDER); and by the Primary Care Interventions to Prevent Maternal and Child Chronic Diseases of Perinatal and Developmental Origin Network (RICORS, RD21/0012/0001), Instituto de Salud Carlos III, Madrid, Spain, funded by the Recovery, Transformation and Resilience Plan 2017–2020, ISCIII, and by the European Union-Next Generation EU. Dr Cruz-Lemini is supported by Juan Rodés contract JR19/00047, Instituto de Salud Carlos III-Spanish Ministry of Health. Funding sources were not involved in study design, collection, analysis, and interpretation of data

    Supporting IrO2 and IrRuOx nanoparticles on TiO2 and Nb-doped TiO2 nanotubes as electrocatalysts for the oxygen evolution reaction

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    IrO2 and IrRuOx (Ir:Ru 60:40 at%), supported by 50 wt% onto titania nanotubes (TNTs) and (3 at% Nb) Nb-doped titania nanotubes (Nb-TNTs), as electrocatalysts for the oxygen evolution reaction (OER), were synthesized and characterized by means of structural, surface analytical and electrochemical techniques. Nb doping of titania significantly increased the surface area of the support from 145 (TNTs) to 260 m2 g−1 (Nb-TNTs), which was significantly higher than those of the Nb-doped titania supports previously reported in the literature. The surface analytical techniques showed good dispersion of the catalysts onto the supports. The X-ray photoelectron spectroscopy analyses showed that Nb was mainly in the form of Nb(IV) species, the suitable form to behave as a donor introducing free electrons to the conduction band of titania. The redox transitions of the cyclic voltammograms, in agreement with the XPS results, were found to be reversible. Despite the supported materials presented bigger crystallite sizes than the unsupported ones, the total number of active sites of the former was also higher due to their better catalyst dispersion. Considering the outer and the total charges of the cyclic voltammograms in the range 0.1-1.4 V, stability and electrode potentials at given current densities, the preferred catalyst was IrO2 supported on the Nb-TNTs. The electrode potentials corresponding to given current densities were between the smallest ones given in the literature despite the small oxide loading used in this work and its Nb doping, thus making the Nb-TNTs-supported IrO2 catalyst a promising candidate for the OER. The good dispersion of IrO2, high specific surface area of the Nb-doped supports, accessibility of the electroactive centers, increased stability due to Nb doping and electron donor properties of the Nb(IV) oxide species were considered the main reasons for its good performance

    Impact of ocean-atmosphere coupling on regional climate: the Iberian Peninsula case

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    Regional models used for downscaling the European climate usually include a relatively small area of the Atlantic Ocean and are uncoupled, with the SST used as lower boundary conditions much coarser than the mesh of the regional atmospheric model. Concerns thus arise about the proper representation of the oceanic influence and the role of air-sea coupling in such experiments. A complex orography and the exposure to different air and ocean masses make the Iberian Peninsula (IP) an ideal test case for exploring the impact of including explicitly the North Atlantic in the regional domain and the added value that coupling brings to regional climate modeling. To this end, the regionally-coupled model ROM and its atmospheric component, the regional atmospheric model REMO are used in a set of coupled and uncoupled experiments forced by the ERA-Interim reanalysis and by the global climate model MPI-ESM. The atmospheric domain is the same in all simulations and includes the North Atlantic and the ocean component is global and eddy permitting. Results show that the impact of air-sea coupling on the IP winter biases can be traced back to the features of the simulated North Atlantic Ocean circulation. In summer, it is the air-sea interactions in the Mediterranean that exert the largest influence on the regional biases. Despite improvements introduced by the eddy-permitting ocean, it is suggested that a higher resolution could be needed for a correct simulation of the features of the large-scale atmospheric circulation that impact the climate of the IP

    Insights into the procoagulant profile of patients with systemic lupus erythematosus without antiphospholipid antibodies

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    We aimed to identify the key players in the prothrombotic profile of patients with systemic lupus erythematosus (SLE) not mediated by antiphospholipid antibodies, as well as the potential utility of global coagulation tests to characterize hemostasis in these patients. Patients with SLE without antiphospholipid antibodies and without signs of thrombosis were included. The kinetics of clot formation were determined by ROTEM®. Platelet activation markers were determined by flow cytometry. Thrombin generation associated with Neutrophil Extracellular Traps (NETs) and microparticles (MPs) was measured by calibrated automated thrombogram (CAT). The plasma levels of PAI-1 were also determined. ROTEM® showed a procoagulant profile in SLE patients. SLE patients had activated platelets and more leukocyte/platelet aggregates at basal conditions. The plasma PAI-1 and platelet aggregates correlated with several ROTEM® parameters. The thrombin generation associated withthe tissue factor (TF) content of MPs and with NETs was increased. Our results suggest the utility of global tests for studying hemostasis in SLE patients because they detect their procoagulant profile, despite having had neither antiphospholipid antibodies nor any previous thrombotic event. A global appraisal of hemostasis should, if possible, be incorporated into clinical practice to detect the risk of a thrombotic event in patients with SLE and to consequently act to prevent its occurrenceThis work was supported by grant from the FIS-FONDOS FEDER (PI19/00772, NVB). E.M.M. holds a predoctoral fellowship from Fundación Española de Trombosis y Hemostasia (FETH-SETH

    Efficient PGD-based dynamic calculation of non-linear soil behavior

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    Non-linear behavior of soils during a seismic event has a predominant role in current site response analysis. Soil response analysis consistently indicates that the stress-strain relationship of soils is nonlinear and shows hysteresis. When focusing in forced response simulations, time integrations based on modal analysis are widely considered, however parametric analysis, non-linear behavior and complex damping functions make difficult the online use of standard discretization strategies, e.g. those based on the use of finite element. In this paper we propose a new harmonic analysis formulation, able to address forced response simulation of soils exhibiting their characteristic nonlinear behavior. The solution can be evaluated in real-time from the offline construction of a parametric solution of the associated linearized problem within the Proper Generalized Decomposition framework

    Leucaena leucocephala cv Perú in Association with Graminaceae in Dryland Conditions for Final Bovine Fattening Stage

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    To evaluate the factors that affect efficiency in a Leucaena leucocephala cv Perú association, with pastures for bovine fattening, 22 Zebu fattening cycles were studied on a farm of the Rectangulo Livestock Company, in Camagüey, Cuba, between 2002 and 2012. The local soil is brown without carbonates. The climate is tropical humid, and the annual precipitation average is 1 183mm. The factors evaluated were food balance, duration of the fattening cycle, and quantity of animals/cycle. The daily weight gain and expenses/income per operation were also analyzed. The pasture and Leucaena percentages were determined by plant counts. Food balances were estimated. The final value of the population of Leucaena cv Perú was 93% (P <0.05), with an increase in common Bermuda grass and other pastures. Short duration tests showed much higher gains (P <0.05), with values above 1.0 kg/animal/day. The number of animal/cycle (P <0.05) produced higher gains with fewer animals. Forest-grazing in association with Leucaena leucocephala cv Perú-graminaceae under dryland conditions produced mean daily gains above 0.800 kg/animal/day in the final stage of fattening bulls, based on food balances with adequate biological and economic results. The best behavior was observed in the shortest cycles, where the highest final weight/animal values were achieved, with fewer expenses and higher income

    Bio-economic Impact of Strategic Changes in Murrah River Buffalo Management

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    The aim of this paper was to evaluate the effects of changes in the strategy to manage the bio-economic efficiency of a Murrah Buffalo production system in the province of Camagüey, Cuba, located 21º north and 77º west, 217 meters above sea level. The climate is tropical humid (Aw) of plains. The mean annual precipitations were 1 180 mm (71% between May and October), the temperatures were between 24 and 29 °C. The soil is brown, without carbonates, and brown-red fersiallitic. The system comprises 5 100 ha and has 536 workers/year. A strategy to introduce management changes in agro-technical, food, reproductive, replacement, health, salary policy, and training was implemented as part of an innovation package with a systemic and participatory approach. The evaluation lasted eight years, and it was critical to increase dairy production in more than 200 000 kg/year in 2012, in comparison to 2004, with improvements in natality and reduction of operational expenses of the system. It was concluded that the strategy had a determining effect on the system's indicators

    Neutral Bremsstrahlung Emission in Xenon Unveiled

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    [EN] We present evidence of non-excimer-based secondary scintillation in gaseous xenon, obtained using both the NEXT-White time projection chamber (TPC) and a dedicated setup. Detailed comparison with first-principle calculations allows us to assign this scintillation mechanism to neutral bremsstrahlung (NBrS), a process that is postulated to exist in xenon that has been largely overlooked.The NEXT Collaboration acknowledges support from the following agencies and institutions: the European Research Council (ERC) under Advanced Grant No. 339787-NEXT; the European Unions Framework Program for Research and Innovation Horizon 2020 (20142020) under Grant Agreements No. 674896, No. 690575, and No. 740055; the Ministerio de Economa y Competitividad and the Ministerio de Ciencia, Innovacin y Universidades of Spain under Grants No. FIS2014-53371-C04 and No. RTI2018-095979, the Severo Ochoa Program Grants No. SEV-2014-0398 and No. CEX2018-000867-S, and the Mara de Maeztu Program MDM-2016-0692; the Generalitat Valenciana under Grants No. PROMETEO/2016/120 and No. SEJI/2017/011; the Portuguese FCT under Project No. PTDC/FIS-NUC/3933/2021 and under Project No. UIDP/04559/2020 to fund the activities of LIBPhys-UC; the U.S. Department of Energy under Contracts No. DE-AC02-06CH11357 (Argonne National Laboratory), No. DE-AC02-07CH11359 (Fermi National Accelerator Laboratory), No. DE-FG02-13ER42020 (Texas A&M), and No. DE-SC0019223/DE-SC0019054 (University of Texas at Arlington); and the University of Texas at Arlington (USA). D. G.-D. acknowledges Ramon y Cajal program (Spain) under Contract No. RYC- 2015-18820. J. M.-A. acknowledges support from Fundacin Bancaria la Caixa (ID 100010434), Grant No. LCF/BQ/PI19/11690012. We would like to thank Lorenzo Muniz for insightful discussions on the subtleties of electron transport in gases.Henriques, C.; Amedo, P.; Teixeira, JMR.; González-Díaz, D.; Azevedo, C.; Para, A.; Martín-Albo, J.... (2022). Neutral Bremsstrahlung Emission in Xenon Unveiled. Physical Review X. 12(2):021005-1-021028-23. https://doi.org/10.1103/PhysRevX.12.021005021005-1021028-2312
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