Pressure dependence of the silicon carbide synthesis temperature

The starting temperature for SiC synthesis from elemental silicon, carbon black, and graphite powders was determined for pressures ranging from 0.8 to 11 GPa by in situ X-ray diffraction experiments. The synthesized SiC corresponds to the cubic 3C phase with the presence of stacking faults along the [111] direction. The lowest density of the stacking faults is achieved when black carbon is used instead of graphite. The minimum temperature to start the Si + C → SiC reaction slightly decreases when the pressure is increased up to 6 GPa and the reaction begins before silicon melts. For pressures higher than 8 GPa, the starting temperature increases, and the formation of SiC from the SiII phase requires the complete melting of silicon. Bulk modulus Bo= 236(14) GPa was obtained for the synthesized SiC phase.Fil: Limandri, Silvina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Garbarino, G.. European Synchrotron Radiation; FranciaFil: Sifre, D.. European Synchrotron Radiation; FranciaFil: Mezouar, M.. European Synchrotron Radiation; FranciaFil: Galván Josa, Víctor Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin

Pre-fire aboveground biomass, estimated from LiDAR, spectral and field inventory data, as a major driver of burn severity in maritime pine (Pinus pinaster) ecosystems

100022Background: The characterization of surface and canopy fuel loadings in fire-prone pine ecosystems is critical for understanding fire behavior and anticipating the most harmful ecological effects of fire. Nevertheless, the joint consideration of both overstory and understory strata in burn severity assessments is often dismissed. The aim of this work was to assess the role of total, overstory and understory pre-fire aboveground biomass (AGB), estimated by means of airborne Light Detection and Ranging (LiDAR) and Landsat data, as drivers of burn severity in a megafire occurred in a pine ecosystem dominated by Pinus pinaster Ait. in the western Mediterranean Basin. Results: Total and overstory AGB were more accurately estimated (R2 equal to 0.72 and 0.68, respectively) from LiDAR and spectral data than understory AGB (R2 ¼ 0.26). Density and height percentile LiDAR metrics for several strata were found to be important predictors of AGB. Burn severity responded markedly and non-linearly to total (R2 ¼ 0.60) and overstory (R2 ¼ 0.53) AGB, whereas the relationship with understory AGB was weaker (R2 ¼ 0.21). Nevertheless, the overstory plus understory AGB contribution led to the highest ability to predict burn severity (RMSE ¼ 122.46 in dNBR scale), instead of the joint consideration as total AGB (RMSE ¼ 158.41). Conclusions: This study novelty evaluated the potential of pre-fire AGB, as a vegetation biophysical property derived from LiDAR, spectral and field plot inventory data, for predicting burn severity, separating the contribution of the fuel loads in the understory and overstory strata in Pinus pinaster stands. The evidenced relationships between burn severity and pre-fire AGB distribution in Pinus pinaster stands would allow the implementation of threshold criteria to support decision making in fuel treatments designed to minimize crown fire hazard.S

Obtención y Análisis del Modelo Dinámico del Sistema de Levitación Magnética: Anillo de Thomson

En este trabajo se muestra el desarrollo y análisis del modelo dinámico del Anillo de Thomson, esto se realiza tomando en consideración el impacto del cambio de la posición del anillo en los parámetros eléctricos y magnéticos. Se utiliza el método de elemento finito para determinar el campo magnético y se realiza la estimación algunos parámetros, se simula el sistema de levitación magnética a diferentes niveles deexcitación para analizar el comportamiento de la posición del anillo y se validan losresultados con experimentos, demostrando que se puede modelar el sistema completosin necesidad de hacer las suposiciones clásicas que simplifican el análisis. El objetivode realizar un modelo dinámico relativamente más completo es el de poder diseñarmejores estrategias de control para las diferentes aplicaciones que se le puede dar enlos sistemas que funcionan con levitación magnética

Highly Active and Stable Ni/La-Doped Ceria Material for Catalytic CO2Reduction by Reverse Water-Gas Shift Reaction

[EN] The design of an active, effective, and economically viable catalyst for CO2 conversion into value-added products is crucial in the fight against global warming and energy demand. We have developed very efficient catalysts for reverse water-gas shift (rWGS) reaction. Specific conditions of the synthesis by combustion allow the obtention of macroporous materials based on nanosized Ni particles supported on a mixed oxide of high purity and crystallinity. Here, we show that Ni/La-doped CeO2 catalysts─with the "right"Ni and La proportions─have an unprecedented catalytic performance per unit mass of catalyst for the rWGS reaction as the first step toward CO2 valorization. Correlations between physicochemical properties and catalytic activity, obtained using a combination of different techniques such as X-ray and neutron powder diffraction, Raman spectroscopy, in situ near ambient pressure X-ray photoelectron spectroscopy, electron microscopy, and catalytic testing, point out to optimum values for the Ni loading and the La proportion. Density functional theory calculations of elementary steps of the reaction on model Ni/ceria catalysts aid toward the microscopic understanding of the nature of the active sites. This finding offers a fundamental basis for developing economical catalysts that can be effectively used for CO2 reduction with hydrogen. A catalyst based on Ni0.07/(Ce0.9La0.1Ox)0.93 shows a CO production of 58 × 10-5 molCO·gcat-1·s-1 (700 °C, H2/CO2 = 2; selectivity to CO > 99.5), being stable for 100 h under continuous reaction.We acknowledge the financial support of the Spanish Ministry of Science and Innovation (PID2021-123287OB-I00, PID2021-122477-OB-I00, PID2021-128915NB-I00, and RTI2018-101604-B-I00) and of the CSIC through the i-LINK 2021 program (LINKA20408). Financial support has also been received from AEI-MINECO/FEDER (Nympha Project, PID2019-106315RB-I00), “Comunidad de Madrid” regional government, and the European Structural Funds (FotoArt-CM project, S2018/NMT-4367). Authors also acknowledge financial support from the grant PLEC2021-007906 funded by MCIN/AEI/10.13039/501100011033 and the “European Union NextGenerationEU/PRTR”. We are grateful to ILL (France) for making all facilities available. This project also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 832121. Computer time provided by the RES (Red Española de Supercomputación) resources at the MareNostrum 4 (BSC, Barcelona) node and the DECI resources at the BEM cluster of the WCSS based in Poland with the support from PRACE aislb is acknowledged

Expression of sterol regulatory element-binding proteins in epicardial adipose tissue in patients with coronary artery disease and diabetes mellitus: preliminary study

[Abstract] Objectives: Sterol regulatory element-binding proteins (SREBP) genes are crucial in lipid biosynthesis and cardiovascular homeostasis. Their expression in epicardial adipose tissue (EAT) and their influence in the development of coronary artery disease (CAD) and type-2 diabetes mellitus remain to be determined. The aim of our study was to evaluate the expression of SREBP genes in EAT in patients with CAD according to diabetes status and its association with clinical and biochemical data. Methods: SREBP-1 and SREBP-2 mRNA expression levels were measured in EAT from 49 patients with CAD (26 with diabetes) and 23 controls without CAD or diabetes. Results: Both SREBPs mRNA expression were significantly higher in patients with CAD and diabetes (p<0.001) and were identified as independent cardiovascular risk factor for coronary artery disease in patients with type-2 diabetes (SREBP-1: OR 1.7, 95%CI 1.1-2.5, p=0.02; SREBP-2: OR 1.6, 95%CI 1.2-3, p=0.02) and were independently associated with the presence of multivessel CAD, left main and anterior descending artery stenosis, and higher total and LDL cholesterol levels, and lower HDL cholesterol levels, in patients with CAD and diabetes. Conclusions: SREBP genes are expressed in EAT and were higher in CAD patients with diabetes than those patients without CAD or diabetes. SREBP expression was associated as cardiovascular risk factor for the severity of CAD and the poor lipid control. In this preliminary study we suggest the importance of EAT in the lipid metabolism and cardiovascular homeostasis for coronary atherosclerosis of patients with diabetes and highlight a future novel therapeutic target.Instituto de Salud Carlos III; PI13/02542Instituto de Salud Carlos III; PI11/01661Red de Investigación Cardiovascular; RD12/0042/003

¿Son diferentes los rasgos biológicos de las plantas en relación con la severidad de incendios en pinares propensos al fuego?

Los incendios forestales pueden ejercer una presión selectiva sobre las características biológicas de las especies en ecosistemas propensos al fuego. El objetivo del estudio es determinar si los rasgos biológicos de las especies leñosas del sotobosque son distintos bajo diferentes escenarios de severidad del fuego en pinares de Pinus pinaster y Pinus halepensis. Para abordar este objetivo se seleccionaron dos grandes incendios ocurridos en 2012 (Sierra del Teleno-León y Cortes de Pallás-Valencia). Tres años después del incendio se establecieron parcelas de campo, en las que se midieron los diámetros mínimos remanentes de una especie leñosa representativa de la comunidad para determinar el nivel de severidad (baja, moderada y alta). También se muestrearon las coberturas visuales de las especies leñosas del sotobosque, que se clasificaron en función a sus rasgos biológicos (estrategia de regeneración, presencia de lignotubérculo, dormición y capacidad de dispersión de las semillas). Los resultados mostraron que la alta severidad redujo la cobertura de especies que usan el rebrote para regenerar, independientemente de la presencia de lignotubérculo, e incrementó la cobertura de germinadoras. Las especies germinadoras con dormición física se vieron favorecidas, mientras que la capacidad de dispersión no supuso una ventaja en relación con la severida

Analysis of CpG methylation sites and CGI among human papillomavirus DNA genomes

<p>Abstract</p> <p>Background</p> <p>The Human Papillomavirus (HPV) genome is divided into early and late coding sequences, including 8 open reading frames (ORFs) and a regulatory region (LCR). Viral gene expression may be regulated through epigenetic mechanisms, including cytosine methylation at CpG dinucleotides. We have analyzed the distribution of CpG sites and CpG islands/clusters (CGI) among 92 different HPV genomes grouped in function of their preferential tropism: cutaneous or mucosal. We calculated the proportion of CpG sites (PCS) for each ORF and calculated the expected CpG values for each viral type.</p> <p>Results</p> <p>CpGs are underrepresented in viral genomes. We found a positive correlation between CpG observed and expected values, with mucosal high-risk (HR) virus types showing the smallest O/E ratios. The ranges of the PCS were similar for most genomic regions except <it>E4</it>, where the majority of CpGs are found within islands/clusters. At least one CGI belongs to each <it>E2/E4 </it>region. We found positive correlations between PCS for each viral ORF when compared with the others, except for the LCR against four ORFs and <it>E6 </it>against three other ORFs. The distribution of CpG islands/clusters among HPV groups is heterogeneous and mucosal HR-HPV types exhibit both lower number and shorter island sizes compared to cutaneous and mucosal Low-risk (LR) HPVs (all of them significantly different).</p> <p>Conclusions</p> <p>There is a difference between viral and cellular CpG underrepresentation. There are significant correlations between complete genome PCS and a lack of correlations between several genomic region pairs, especially those involving LCR and <it>E6</it>. <it>L2 </it>and <it>L1 </it>ORF behavior is opposite to that of oncogenes <it>E6 </it>and <it>E7</it>. The first pair possesses relatively low numbers of CpG sites clustered in CGIs while the oncogenes possess a relatively high number of CpG sites not associated to CGIs. In all HPVs, <it>E2/E4 </it>is the only region with at least one CGI and shows a higher content of CpG sites in every HPV type with an identified <it>E4</it>. The mucosal HR-HPVs show either the shortest CGI size, followed by the mucosal LR-HPVs and lastly by the cutaneous viral subgroup, and a trend to the lowest CGI number, followed by the cutaneous viral subgroup and lastly by the mucosal LR-HPVs.</p

Association Patterns in Saproxylic Insect Networks in Three Iberian Mediterranean Woodlands and Their Resistance to Microhabitat Loss

The assessment of the relationship between species diversity, species interactions and environmental characteristics is indispensable for understanding network architecture and ecological distribution in complex networks. Saproxylic insect communities inhabiting tree hollow microhabitats within Mediterranean woodlands are highly dependent on woodland configuration and on microhabitat supply they harbor, so can be studied under the network analysis perspective. We assessed the differences in interacting patterns according to woodland site, and analysed the importance of functional species in modelling network architecture. We then evaluated their implications for saproxylic assemblages’ persistence, through simulations of three possible scenarios of loss of tree hollow microhabitat. Tree hollow-saproxylic insect networks per woodland site presented a significant nested pattern. Those woodlands with higher complexity of tree individuals and tree hollow microhabitats also housed higher species/interactions diversity and complexity of saproxylic networks, and exhibited a higher degree of nestedness, suggesting that a higher woodland complexity positively influences saproxylic diversity and interaction complexity, thus determining higher degree of nestedness. Moreover, the number of insects acting as key interconnectors (nodes falling into the core region, using core/periphery tests) was similar among woodland sites, but the species identity varied on each. Such differences in insect core composition among woodland sites suggest the functional role they depict at woodland scale. Tree hollows acting as core corresponded with large tree hollows near the ground and simultaneously housing various breeding microsites, whereas core insects were species mediating relevant ecological interactions within saproxylic communities, e.g. predation, competitive or facilitation interactions. Differences in network patterns and tree hollow characteristics among woodland sites clearly defined different sensitivity to microhabitat loss, and higher saproxylic diversity and woodland complexity showed positive relation with robustness. These results highlight that woodland complexity goes hand in hand with biotic and ecological complexity of saproxylic networks, and together exhibited positive effects on network robustness.The research Projects I+D CGL2011-23658 y CGL2012-31669 of the Spanish Minister of Science provided economic support

A Comparative Life Cycle Assessment and Costing of Lighting Systems for Environmental Design and Construction of Sustainable Roads

The management of the life cycle of the transport network is one of the main challenges of sustainable mobility. Roads and highways cause significant damage to the ecosystem. Specifically, lighting systems contribute to climate change, energy consumption, and human health effects. In this context, this work proposes the combination of life cycle assessment (LCA) with life cycle costing (LCC) to analyze the eco-efficiency of the life cycle of a road, including evaluation of the relative contribution of the lighting system to the total impact. Four scenarios were included in the model: (S1) high-pressure sodium lamps with ballast powered from the grid; (S2) halogen lamps powered from the grid; (S3) light-emitting diode lamps powered from the grid; and (S4) light-emitting diode lamps powered from a standalone photovoltaic system. The life cycle stages of raw material extraction, construction, use, maintenance, and end of road life were included in the analysis. The results show that scenarios S3 and S1 are the most eco-efficient relative to the less favorable S2 scenario (80% and 74% lower, respectively). Scenarios with the least environmental impact are the most economically viable

Cation distribution and magnetic properties of LiMnZn ferrites

Spinel compounds Li0.5xZn0.6xMn0.4Fe2+0.5xO4 (x = 0.0; 0.1; 0.2; 0.4) were produced by the selfcombustion sol–gel method. The obtained powders were calcined at 1000 C for 2 h in Ar atmosphere . The structural and microstructural characteristics of the resulting samples were studied by magnetization measurements, Mössbauer spectroscopy and X-ray powder diffraction in combination with the Rietveld method. Based on magnetization results, a cation distribution model is proposed which is tested with Rietveld refinements and supported by Mössbauer results. The observed increase in saturation magnetization wit h Li content in the structure is explained by an unusual distribution of Zn2+ ions in octahedral sites.Fil: Arana, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Física "Enrique Gaviola"; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Galván Josa, Víctor Martín. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Física "Enrique Gaviola"; ArgentinaFil: Jacobo, S. E.. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Bercoff, Paula Gabriela. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Física "Enrique Gaviola"; Argentin