5,106 research outputs found

    Laser treatment in diabetic retinopathy

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    Diabetic retinopathy is a leading cause of visual impairment and blindness in developed countries due to macular edema and proliferative diabetic retinopathy (PDR). For both complications laser treatment may offer proven therapy: the Diabetic Retinopathy Study demonstrated that panretinal scatter photocoagulation reduces the risk of severe visual loss by >= 50% in eyes with high-risk characteristics. Pan-retinal scatter coagulation may also be beneficial in other PDR and severe nonproliferative diabetic retinopathy (NPDR) under certain conditions. For clinically significant macular edema the Early Treatment of Diabetic Retinopathy Study could show that immediate focal laser photocoagulation reduces the risk of moderate visual loss by at least 50%. When and how to perform laser treatment is described in detail, offering a proven treatment for many problems associated with diabetic retinopathy based on a high evidence level. Copyright (c) 2007 S. Karger AG, Basel

    Charmonium suppression from purely geometrical effects

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    The extend to which geometrical effects contribute to the production and suppression of the J/ψJ/\psi and qqˉq\bar{q} minijet pairs in general is investigated for high energy heavy ion collisions at SPS, RHIC and LHC energies. For the energy range under investigation, the geometrical effects referred to are shadowing and anti-shadowing, respectively. Due to those effects, the parton distributions in nuclei deviate from the naive extrapolation from the free nucleon result; fA≠AfNf_{A}\neq A f_{N}. The strength of the shadowing/anti-shadowing effect increases with the mass number. The consequences of gluonic shadowing effects for the xFx_F distribution of J/ψJ/\psi's at s=20\sqrt s =20 GeV, s=200\sqrt s =200 GeV and s=6\sqrt s =6 TeV are calculated for some relevant combinations of nuclei, as well as the pTp_T distribution of minijets at midrapidity for Nf=4N_f=4 in the final state.Comment: corrected some typos, improved shadowing ratio
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