810 research outputs found

    Long-term follow-up of myopic choroidal neovascularization treated with ranibizumab

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    PURPOSE: To evaluate the long-term safety and efficacy of intravitreal ranibizumab in the treatment of myopic choroidal neovascularization (CNV). METHODS: Three-year retrospective, nonrandomized, interventional case series. Forty eyes of 39 patients with myopic CNV were included; 15 with previous photodynamic therapy, and 25 naïve eyes. Best-corrected visual acuity (BCVA) changes, central foveal thickness (CFT), and number of treatments were assessed, from baseline to month 36. RESULTS: Mean visual acuity improved from 55.4 Early Treatment Diabetic Retinopathy Study (ETDRS) letters at baseline to 59.7 letters at 12 months (p = 0.07), 61.8 letters at 24 months (p = 0.008) and 63.4 letters at 36 months (p = 0.039). Twenty-five percent of the patients gained ≥15 letters (3 lines) at 12 months, 30% at 24 months and 35% at 36 months. There was a mean reduction of 80 μm in CFT (p < 0.001). A mean of 4.1 injections were performed in the first year, 2.4 in the second year and 1.1 in the third year. Fifty-three percent of the eyes had no need for treatment during the third year of follow-up. CONCLUSIONS: Intravitreal ranibizumab seems to be an effective and safe therapeutic procedure to treat CNV in highly myopic eyes, with a high proportion of patients gaining or stabilizing BCVA at a 3-year follow-up.info:eu-repo/semantics/publishedVersio

    Long-term chorioretinal changes after photodynamic therapy for chronic central serous chorioretinopathy

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    PURPOSE: To evaluate morphological and functional chorioretinal changes 5 years after standard photodynamic therapy (PDT) for chronic central serous chorioretinopathy (CSC). METHODS: A retrospective, nonrandomized study, including patients with chronic CSC treated with standard PDT and followed for at least 60 months. All patients underwent a complete ophthalmological examination, and the location and number of treatments were registered. Five or more years after treatment, subfoveal and non-subfoveal treated areas were evaluated with Spectralis optical coherence tomography and microperimetry. RESULTS: Seventeen eyes of 15 patients were included, with mean age of 48.3 ± 8.4 years and a mean follow-up of 80.6 ± 12.4 months (range from 62 to 104 months). All eyes had neurosensory detachment (NSD) at baseline. Treatment was performed under the fovea in 58.8 % and in a non-foveal area in 41.2 % of the eyes. At the final visit all eyes had resolution of the NSD, with a statistical significant reduction in central macular thickness (p = 0.005) and preserved neuroretinal thickness (p = 0.839). There was a statistical difference between initial and final BCVA (p < 0.001) and a mean gain of 8.4 ± 7.8 letters. Subfoveal morphological changes in external limiting membrane (ELM) and in photoreceptor inner and outer segment junction (IS/OS) were correlated with final BCVA (p = 0.015 and p = 0.014 respectively), but not with the variation of BCVA. There was a statistical correlation between morphological changes in IS/OS line and retinal sensitivity in the central 12° and 2° (p = 0.003 and p = 0.002 respectively). The morphological changes in the subfoveal layers were not dependent on treatment location (p = 0.154, p = 0.644, and p = 1.0 for ELM, IS/OS line, and retinal pigment epithelium respectively). Subfoveal final mean choroidal thickness was 295.1 ± 68.7 μm, and showed no statistical difference from the normal population (p = 0.633). CONCLUSIONS: Morphological and functional chorioretinal changes, observed 5 or more years after standard PDT for chronic CSC, were not correlated with the location of treatment, neither with the progression of visual acuity or with the location of treatment, and are more likely to be related to the disease itself than with the treatment provided.info:eu-repo/semantics/publishedVersio

    Biological interactions between nematophagous fungi, Esteya spp., and the pinewood nematode, Bursaphelenchus xylophilus

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    The pinewood nematode (PWN), Bursaphelenchus xylophilus, is a quarantine organism in several countries and the causal agent of pine wilt disease (PWD), a serious threat to pine forests worldwide. PWD results from complex interactions between the nematode, its insect vector, Monochamus spp., and host plants (conifers), being the nematode the common element in this interaction. The PWN is considered the sixth most economically important plant-parasitic nematode. In Europe, this pest was first reported in Portugal in 1999, in maritime pine, Pinus pinaster. Due to its economic importance and worldwide distribution, an enormous amount of effort is devoted to research on B. xylophilus and PWD. Scenarios strongly suggest that climate change is likely going to cause a spread of PWD and outbreaks in areas free of the disease. The urgent need for sustainable management strategies has led to an increasing interest in antagonists capable of suppressing the PWN. Nematophagous fungi belonging to the Esteya genus are reported as natural enemies of the PWN and promising biocontrol agents. There are currently two described species: E. vermicola and E. floridanum, the first of which is capable of mimicking volatile organic compounds produced naturally by Pinus spp. in order to attract PWN. However, few studies have been carried out on the development of Esteya spp. inside pine trees, and none using maritime pine, the main and most affected species in Portuguese forests and its largest carbon reservoir. It is therefore crucial to understand the plant-nematode-fungus interactions between P. pinaster, B. xylophilus and Esteya spp. In this sense, biological interactions between these two antagonists, the PWN and P. pinaster were investigated, namely fungus-fungus, fungus-nematode and fungus-tree, as well as feeding trials and chemotaxis assays, to determine the attractive power of both fungal species. These results will enlighten us on the most promising species for biocontrol and help us devise new ways to manage PWD

    Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

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    The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry

    Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using √s=8 TeV proton-proton collision data

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    A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector

    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

    Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

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    The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV

    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

    Measurement of the charge asymmetry in dileptonic Decays of top quark pairs in pp collisions at √ s = 7 TeV using the ATLAS detector

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    A measurement of the top-antitop (tt) charge asymmetry is presented using data corresponding to an integrated luminosity of 4.6 fb −1 of LHC pp collisions at a centre- of-mass energy of 7 TeV collected by the ATLAS detector. Events with two charged leptons, at least two jets and large missing transverse momentum are selected. Two observables are studied: A tt/C, based on the reconstructed tt final state. The asymmetries are measured to be A ll/C = 0.024 +/- 0.015 (stat.) +/- 0.009 (syst.) Att/C = 0.021 +/- 0.025 (stat.) +/- 0.017 (syst.) The measured values are in agreement with the Standard Model predictions
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