799 research outputs found

    Prognostic factors in node-negative colorectal cancer: a retrospective study from a prospective database

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    PURPOSE: There is a need to identify a subgroup of high-risk patients with node-negative colorectal cancer who have a poor long-term prognosis and may benefit from adjuvant therapies. The aim of this study was to evaluate the prognostic impact of clinical and pathological parameters in a retrospective study from a prospective, continuous database of homogenously treated patients. METHODS: This study included 362 patients operated in a single institution for Dukes A and B (node-negative) colorectal cancer. The median follow-up was 140 months. The prognostic value of 13 clinical and pathological parameters was investigated. RESULTS: Multivariate analysis identified six independent prognostic factors: age at time of diagnosis (hazard ratio (HR) = 1.076), number of lymph nodes removed (HR = 0.948), perineural invasion (HR = 2.173), venous invasion (HR = 1.959), lymphatic vessel invasion (HR = 2.126), and T4 stage (HR = 5.876). CONCLUSION: These parameters could be useful in identifying patients with high-risk node-negative colorectal cancer who should be presented to adjuvant therapy

    Adaptive optics for the LEP 2 synchrotron light monitors

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    The image obtained with the LEP synchrotron radiation telescopes deteriorates, giving multiple and deformed images, when the beam energy goes beyond 80 GeV at beam currents above 2 mA. This problem is due to the deformation of the light extracting beryllium mirror, by as little as 1 mm, and had been predicted at the design stage. To overcome this problem, several changes together with an adaptive optics set-up have been introduced. These essentially consist of a cylindrically deformable mirror to compensate the cylindrical deformation of the beryllium mirror and a movable detector to compensate the spherical deformation. Both components are continuously adjusted as a function of beam current and energy

    The Luminescence Profile Monitor of the CERN SPS

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    The SPS luminescence monitor is the first device of this type to be used in a high energy accelerator, from 14 to 450 GeV, where up till now the light production was considered to be insufficient. It uses Nitrogen at pressures as low as 4 10-6 Pa as the scintillation medium. Light production, spectrum and decay times have been measured and compared with theory and existing low energy data. They are important factors for the design of such monitors for other machines, for example LHC

    The Extended Baryon Oscillation Spectroscopic Survey: Variability Selection and Quasar Luminosity Function

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    The SDSS-IV/eBOSS has an extensive quasar program that combines several selection methods. Among these, the photometric variability technique provides highly uniform samples, unaffected by the redshift bias of traditional optical-color selections, when z=2.73.5z= 2.7 - 3.5 quasars cross the stellar locus or when host galaxy light affects quasar colors at z<0.9z < 0.9. Here, we present the variability selection of quasars in eBOSS, focusing on a specific program that led to a sample of 13,876 quasars to gdered=22.5g_{\rm dered}=22.5 over a 94.5 deg2^2 region in Stripe 82, an areal density 1.5 times higher than over the rest of the eBOSS footprint. We use these variability-selected data to provide a new measurement of the quasar luminosity function (QLF) in the redshift range 0.68<z<4.00.68<z<4.0. Our sample is denser, reaches deeper than those used in previous studies of the QLF, and is among the largest ones. At the faint end, our QLF extends to Mg(z ⁣= ⁣2)=21.80M_g(z\!=\!2)=-21.80 at low redshift and to Mg(z ⁣= ⁣2)=26.20M_g(z\!=\!2)=-26.20 at z4z\sim 4. We fit the QLF using two independent double-power-law models with ten free parameters each. The first model is a pure luminosity-function evolution (PLE) with bright-end and faint-end slopes allowed to be different on either side of z=2.2z=2.2. The other is a simple PLE at z<2.2z<2.2, combined with a model that comprises both luminosity and density evolution (LEDE) at z>2.2z>2.2. Both models are constrained to be continuous at z=2.2z=2.2. They present a flattening of the bright-end slope at large redshift. The LEDE model indicates a reduction of the break density with increasing redshift, but the evolution of the break magnitude depends on the parameterization. The models are in excellent accord, predicting quasar counts that agree within 0.3\% (resp., 1.1\%) to g<22.5g<22.5 (resp., g<23g<23). The models are also in good agreement over the entire redshift range with models from previous studies.Comment: 15 pages, 12 figures, accepted for publication in A&
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