237 research outputs found

    Identification of tsunami-induced deposits using numerical modeling and rock magnetism techniques: a study case of the 1755 Lisbon tsunami in Algarve, Portugal

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    Storm- and tsunami-deposits are generated by similar depositional mechanisms making their discrimination hard to establish using classic sedimentologic methods. Here we propose an original approach to identify tsunami-induced deposits by combining numerical simulation and rock magnetism. To test our method, we investigate the tsunami deposit of the Boca do Rio estuary generated by the 1755 earthquake in Lisbon which is well described in the literature. We first test the 1755 tsunami scenario using a numerical inundation model to provide physical parameters for the tsunami wave. Then we use concentration (MS. SIRM) and grain size (chi(ARM), ARM, B1/2, ARM/SIRM) sensitive magnetic proxies coupled with SEM microscopy to unravel the magnetic mineralogy of the tsunami-induced deposit and its associated depositional mechanisms. In order to study the connection between the tsunami deposit and the different sedimentologic units present in the estuary, magnetic data were processed by multivariate statistical analyses. Our numerical simulation show a large inundation of the estuary with flow depths varying from 0.5 to 6 m and run up of similar to 7 m. Magnetic data show a dominance of paramagnetic minerals (quartz) mixed with lesser amount of ferromagnetic minerals, namely titanomagnetite and titanohematite both of a detrital origin and reworked from the underlying units. Multivariate statistical analyses indicate a better connection between the tsunami-induced deposit and a mixture of Units C and D. All these results point to a scenario where the energy released by the tsunami wave was strong enough to overtop and erode important amount of sand from the littoral dune and mixed it with reworked materials from underlying layers at least 1 m in depth. The method tested here represents an original and promising tool to identify tsunami-induced deposits in similar embayed beach environments

    Constraining the Matter Power Spectrum Normalization using the SDSS/RASS and REFLEX Cluster surveys

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    We describe a new approach to constrain the amplitude of the power spectrum of matter perturbations in the Universe, parametrized by sigma_8 as a function of the matter density Omega_0. We compare the galaxy cluster X-ray luminosity function of the REFLEX survey with the theoretical mass function of Jenkins et al. (2001), using the mass-luminosity relationship obtained from weak lensing data for a sample of galaxy clusters identified in Sloan Digital Sky Survey commissioning data and confirmed through cross-correlation with the ROSAT all-sky survey. We find sigma_8 = 0.38 Omega_0^(-0.48+0.27 Omega_ 0), which is significantly different from most previous results derived from comparable calculations that used the X-ray temperature function. We discuss possible sources of systematic error that may cause such a discrepancy, and in the process uncover a possible inconsistency between the REFLEX luminosity function and the relation between cluster X-ray luminosity and mass obtained by Reiprich & Bohringer (2001).Comment: Accepted to ApJ Letters. 4 pages using emulateapj.st

    Usando Redes Aleatorias na Analise de Mobilidade

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    National audienceThe constant advancement of information systems has allowed more data to be generated and stored from the most diverse situations. It is fascinating that, behind these records, we see the reflection of the environment itself, since every record represents a decision made by some entity. In this work, we modeled real-world scenarios of mobility from using temporal complex networks. The analysis assumes that these systems are composed of entities able to interact in a rational manner, reflecting their interests and activity dynamic. In this direction, we propose a technique for analyzing mobility scenarios from random graphs. This technique examines how the real system would evolve if the agents' decisions were random, and from there, you can check, for example, which edges are random and which are derived from social relationships, such as friendship or professional.O avanco constante de sistemas de informacao tempermitido que mais dados sejam gerados e armazenados a partir das mais diversas situacoes. E fascinante que, por tras de cada registro, seja possıvel ver o reflexo do ambiente em si, ou seja, alguma decisao tomada por alguma entidade. Neste trabalho, sao estudados cenarios reais de mobilidade a partir de uma modelagem usando redes complexas temporais. A analise parte do pressuposto que esses sistemas sao compostos de entidades capazes de interagir entre si de uma maneira racional, refletindo seus interesses e dinamica de atividade. Nessa direcao, e proposta uma tecnica para analisar cenarios de mobilidade a partir de grafos aleatorios. Essa tecnica verifica como o sistema real evoluiria caso as decisoes dos seus agentes fossem aleat'orias e, a partir dela, pode-se verificar, por exemplo, quais arestas s˜ao aleat'orias e quais s˜ao provenientes de relac¸ ˜oes sociais, tais como relac¸ ˜oes de amizade ou profissionais

    RECAST: Telling Apart Social and Random Relationships in Dynamic Networks

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    International audienceIn this paper, we argue that the ability to accurately spot random and social relationships in dynamic networks is essential to net- work applications that rely on human routines, such as, e.g., op- portunistic routing. We thus propose a strategy to analyze users' interactions in mobile networks where users act according to their interests and activity dynamics. Our strategy, named Random rElationship ClASsifier sTrategy (RECAST), allows classifying users' wireless interactions, separating random interactions from differ- ent kinds of social ties. To that end, RECAST observes how the real system differs from an equivalent one where entities' decisions are completely random. We evaluate the effectiveness of the RECAST classification on real-world user contact datasets collected in diverse networking contexts. Our analysis unveils significant dif- ferences among the dynamics of users' wireless interactions in the datasets, which we leverage to unveil the impact of social ties on opportunistic routing

    Anticipating Future Risks of Climate-Driven Wildfires in Boreal Forests

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    Extreme forest fires have historically been a significant concern in Canada, the Russian Federation, the USA, and now pose an increasing threat in boreal Europe. This paper deals with application of the wildFire cLimate impacts and Adaptation Model (FLAM) in boreal forests. FLAM operates on a daily time step and utilizes mechanistic algorithms to quantify the impact of climate, human activities, and fuel availability on wildfire probabilities, frequencies, and burned areas. In our paper, we calibrate the model using historical remote sensing data and explore future projections of burned areas under different climate change scenarios. The study consists of the following steps: (i) analysis of the historical burned areas over 2001–2020; (ii) analysis of temperature and precipitation changes in the future projections as compared to the historical period; (iii) analysis of the future burned areas projected by FLAM and driven by climate change scenarios until the year 2100; (iv) simulation of adaptation options under the worst-case scenario. The modeling results show an increase in burned areas under all Representative Concentration Pathway (RCP) scenarios. Maintaining current temperatures (RCP 2.6) will still result in an increase in burned area (total and forest), but in the worst-case scenario (RCP 8.5), projected burned forest area will more than triple by 2100. Based on FLAM calibration, we identify hotspots for wildland fires in the boreal forest and suggest adaptation options such as increasing suppression efficiency at the hotspots. We model two scenarios of improved reaction times—stopping a fire within 4 days and within 24 h—which could reduce average burned forest areas by 48.6% and 79.2%, respectively, compared to projected burned areas without adaptation from 2021–2099

    Detection and Quantitative Analysis of Two Independent Binding Modes of a Small Ligand Responsible for DC-SIGN Clustering

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    DC-SIGN (dendritic cell-specific ICAM-3 grabbing non-integrin) is a C-type lectin receptor (CLRs) present, mainly in dendritic cells (DCs), as one of the major pattern recognition receptors (PRRs). This receptor has a relevant role in viral infection processes. Recent approaches aiming to block DC-SIGN have been presented as attractive anti-HIV strategies. DC-SIGN binds mannose or fucose-containing carbohydrates from viral proteins such as the HIV envelope glycoprotein gp120. We have previously demonstrated that multivalent dendrons bearing multiple copies of glycomimetic ligands were able to inhibit DC-SIGN-dependent HIV infection in cervical explant models. Optimization of glycomimetic ligands requires detailed characterization and analysis of their binding modes because they notably influence binding affinities. In a previous study we characterized the binding mode of DC-SIGN with ligand 1, which shows a single binding mode as demonstrated by NMR and X-ray crystallography. In this work we report the binding studies of DC-SIGN with pseudotrisaccharide 2, which has a larger affinity. Their binding was analysed by TR-NOESY and STD NMR experiments, combined with the CORCEMA-ST protocol and molecular modelling. These studies demonstrate that in solution the complex cannot be explained by a single binding mode. We describe the ensemble of ligand bound modes that best fit the experimental data and explain the higher inhibition values found for ligand

    Bariatric Surgery Impact on Cardiovascular Risk Factors: Is Age a Factor to Consider?

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    Introduction: Despite the abundance of data addressing the influence of patient's age on surgery-related complications, its impact on cardiometabolic outcomes following bariatric surgery has been overlooked. Methods: Retrospective unicentric study of 1,728 obese patients who underwent bariatric surgery between January 2010 and June 2015. Patients were divided in 3 age groups, according to their age at surgery: ?40 (n = 751), 40-59 (n = 879), and 60 years (n = 98). Parameters with cardiometabolic impact, such as body anthropometric measures, lipid profile, and glycemic status, before and 24 months after surgery, were compared between these groups. A multiple linear regression was performed, adjusting differences between groups for sex, surgery type, and body mass index variation. Results: The group ?40 years presented more weight loss (-35.4 ± 9.0 kg, p ? 0.001), greater BMI reduction (-15.8 ± 6.1 kg/m2, p ? 0.001), and larger changes in waist (-34 ± 13.8 cm, p ? 0.001) and hip circumferences (-28.7 ± 11.9 cm, p ? 0.05). The group of 60 years presented the heaviest reduction in fasting glucose (-17.7 ± 32.8 mg/dL, p ? 0.001) and HbA1c (0.7 ± 1.0, p ? 0.001), and also had a tendency to have the biggest changes in systolic blood pressure (-14.7 ± 18.7 mm Hg, p = 0.071). Conclusion: Patients with 60 years benefit the most from bariatric surgery regarding cardiometabolic parameters, presenting heavier reductions in fasting glucose, as well as HbA1c and a tendency towards a higher decrease in systolic blood pressure. No clinically significant differences in lipid profile were observed between groups. (c) 202

    Particleboard Production from Paulownia tomentosa (Thunb.) Steud. Grown in Portugal

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    Paulownia wood has raised high attention due to its rapid growth and fire resistance. The number of plantations in Portugal has been growing, and new exploitation methods are needed. This study intends to determine the properties of particleboards made with very young Paulownia trees from Portuguese plantations. Single layer particleboards were produced with 3-year-old Paulownia trees using different processing parameters and different board composition in order to determine the best properties for use in dry environments. The standard particleboard was produced at 180 °C and a 36.3 kg/cm2 pressure for 6 min using 40 g of raw material with 10% urea-formaldehyde resin. Higher particle size lead to lower-density particleboards, while higher resin contents lead to higher density of the boards. Density has a major effect on board properties with higher densities improving mechanical properties such as bending strength, modulus of elasticity (MOE) and internal bond, lower water absorption but higher thickness swelling and thermal conductivity. Particleboards meeting the requirements for dry environment according to NP EN 312 standard, could be produced with young Paulownia wood with acceptable mechanical and thermal conductivity properties with density around 0.65 g/cm3 and a thermal conductivity of 0.115 W/mK.info:eu-repo/semantics/publishedVersio

    Adequate magnesium level as an associated factor of pre-diabetes and diabetes mellitus remission in patients with obesity submitted to bariatric surgery

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    Bariatric surgery (BS) can lead to remission of type 2 diabetes mellitus (T2DM), however, the evidence on the influence of preoperative serum magnesium levels on this reversal is scarce. To study the influence of preoperative serum magnesium levels on the pre-T2DM and T2DM remission one year after BS. Retrospective study carried out among 1656 patients with obesity who underwent BS in the Centro Hospitalar Universitário São João. T2DM and pre-T2DM remission were defined as being normal glycaemic measures of at least one year's after BS and without pharmacological therapy. To assess the association between preoperative serum magnesium levels and pre- and T2DM remission, logistic regression models, crude and adjusted for sex, age and body mass index were computed. Patients with normoglycaemia presented hypomagnesaemia less often than those patients with pre-T2DM and T2DM (17.0% vs. 21.3% vs. 39.9%) (p < 0.001). One year after BS, 62.9% of patients with pre-T2DM or T2DM before BS showed remission. Adequate magnesium levels were positively associated with T2DM and pre-T2DM remission, one year after BS (OR 1.79; 95% CI 1.34-2.38), independently of sex, age, and body mass index. Adequate preoperative serum magnesium levels showed to be an important clinical parameter for pre-T2DM and T2DM remission.Isabel Maia holds a PhD Grant (ref:SFRH/BD/117371/2016/PT), which is co-funded by the Foundation for Science and Technology (FCT) and the POCH/FSE Program
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