1,580 research outputs found

    Machine-learning blends of geomorphic descriptors: value and limitations for flood hazard assessment across large floodplains

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    Recent literature shows several examples of simplified approaches that perform flood hazard (FH) assessment and mapping across large geographical areas on the basis of fast-computing geomorphic descriptors. These approaches may consider a single index (univariate) or use a set of indices simultaneously (multivariate). What is the potential and accuracy of multivariate approaches relative to univariate ones? Can we effectively use these methods for extrapolation purposes, i.e., FH assessment outside the region used for setting up the model? Our study addresses these open problems by considering two separate issues: (1) mapping flood-prone areas and (2) predicting the expected water depth for a given inundation scenario. We blend seven geomorphic descriptors through decision tree models trained on target FH maps, referring to a large study area (∼ 105 km2). We discuss the potential of multivariate approaches relative to the performance of a selected univariate model and on the basis of multiple extrapolation experiments, where models are tested outside their training region. Our results show that multivariate approaches may (a) significantly enhance flood-prone area delineation (accuracy: 92%) relative to univariate ones (accuracy: 84%), (b) provide accurate predictions of expected inundation depths (determination coefficient ∼0.7), and (c) produce encouraging results in extrapolation

    A single-center experience on below-the-knee endovascular treatment in diabetic patients

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    Diabetic ulceration of the foot is a major global medical, social and economic problem and is the most frequent end-point of diabetic complications. A retrospective analysis from February 2017 to May 2019 of diabetic patients presenting below-the-knee artery disease (PAD) was carried out. Only patients treated with endovascular techniques as first choice treatment were evaluated. Outcome measured was perioperative mortality and morbidity. Freedom from occlusion, secondary patency and amputation rate were all registered. Additional maneuvers including stenting or angioplasty with drug eluting balloon (DEB) were reported. A total of 167 (101 male/66 female) patients with a mean age of 71 years were included in the study. A Rutherford 3, 4, 5 and 6 categories were reported in 5, 7, 110 and 45 patients, respectively. No perioperative mortality was reported. Morbidity occurred in 4 (4.4%) cases and consisted of pseudoaneurysm. Additional stenting during first procedure was required in 7 (4%) patients, drug eluting balloon was needed in 56 (33%) patients. At 1-year follow-up, estimated freedom from occlusion and secondary patency was 70% and 80% respectively. Major amputation rate was 2.4%, minor amputation rate was 41.9%. In our experience, extreme revascularization in search of distal direct flow reduce the rate of amputations with an increase in ulcer healing. New materials and techniques such as drug eluting technology, used properly, can improve outcome

    Synthesis of L-tricholomic acid analogues and pharmacological characterization at ionotropic glutamate receptors

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    The synthesis of analogues of the natural compound ltricholomic acid and of its threo diastereoisomer was accomplished in order to explore their affinity for glutamate ionotropic receptors. In this study, fourteen new unnatural amino acids, characterized by a 3-hydroxy-~2 -isoxazoline or 3- hydroxy-~2 -pyrazoline-skeleton, were obtained exploiting, as key reaction, a 1,3-dipolar cycloaddition or an intramolecular cyclization

    Synthesis of unusual isoxazoline containing β and γ-dipeptides as potential glutamate receptor ligands

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    New unconventional beta and gamma dipeptides, representing conformationally constrained higher homologues of glutamic acid, have been prepared and tested as new pharmacological tools to investigate the iGluR binding domain, in an attempt to identify potential selective antagonists

    Nucleation and Bulk Crystallization in Binary Phase Field Theory

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    We present a phase field theory for binary crystal nucleation. In the one-component limit, quantitative agreement is achieved with computer simulations (Lennard-Jones system) and experiments (ice-water system) using model parameters evaluated from the free energy and thickness of the interface. The critical undercoolings predicted for Cu-Ni alloys accord with the measurements, and indicate homogeneous nucleation. The Kolmogorov exponents deduced for dendritic solidification and for "soft-impingement" of particles via diffusion fields are consistent with experiment.Comment: 4 pages, 4 figures, accepted to PR

    Rethinking the import-productivity nexus for Italian manufacturing

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    We provide evidence on the firm level productivity effects of imports of intermediates. By exploiting a large panel of Italian manufacturing firms, we are able to separately explore the role of importing from high and low income countries. Importing does not permanently affect the firm productivity growth. This finding holds both when we test for the import entry by means of Propensity Score Matching techniques and when we analyse the import intensity within a dynamic panel data model framework. On the contrary, we confirm the existence of self-selection into importing. Also, our evidence supports the learning-by-exporting effects in Italian manufacturing and we prove that this result is robust to the control of firm import activity

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

    Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

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    Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model
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