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Visual function assessment in simulated real-life situations in patients with age-related macular degeneration compared to normal subjects

UC San Diego Previously Published Works (2014)

Purpose

To evaluate visual function variations in eyes with age-related macular degeneration (AMD) compared to normal eyes under different light/contrast conditions using a time-dependent visual acuity testing instrument, the Central Vision Analyzer (CVA).

Methods

Overall, 37 AMD eyes and 35 normal eyes were consecutively tested with the CVA after assessing best-corrected visual acuity (BCVA) using ETDRS charts. The CVA established visual thresholds for three mesopic environments (M1 (high contrast), M2 (medium contrast), and M3 (low contrast)) and three backlight-glare environments (G1 (high contrast, equivalent to ETDRS), G2 (medium contrast), and G3 (low contrast)) under timed conditions. Vision drop across environments was calculated, and repeatability of visual scores was determined.

Results

BCVA significantly reduced with decreasing contrast in all eyes. M1 scores for BCVA were greater than M2 and M3 (P<0.001); G1 scores were greater than G2 and G3 (P<0.01). BCVA dropped more in AMD eyes than in normal eyes between M1 and M2 (P=0.002) and between M1 and M3 (P=0.003). In AMD eyes, BCVA was better using ETDRS charts compared to G1 (P<0.001). The drop in visual function between ETDRS and G1 was greater in AMD eyes compared to normal eyes (P=0.004). Standard deviations of test-retest ranged from 0.100 to 0.139 logMAR.

Conclusion

The CVA allowed analysis of the visual complaints that AMD patients experience with different lighting/contrast time-dependent conditions. BCVA changed significantly under different lighting/contrast conditions in all eyes, however, AMD eyes were more affected by contrast reduction than normal eyes. In AMD eyes, timed conditions using the CVA led to worse BCVA compared to non-timed ETDRS charts.

Cover page: Visual function assessment in simulated real-life situations in patients with age-related macular degeneration compared to normal subjects

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Search for neutral MSSM Higgs bosons decaying to τ+τ− pairs in proton–proton collisions at s=7 TeV with the ATLAS detector

UC Irvine Previously Published Works (2011)

A search for neutral Higgs bosons decaying to pairs of τ leptons with the ATLAS detector at the LHC is presented. The analysis is based on proton-proton collisions at a center-of-mass energy of 7 TeV, recorded in 2010 and corresponding to an integrated luminosity of 36 pb-1. After signal selection, 276 events are observed in this data sample. The observed number of events is consistent with the total expected background of 269±36 events. Exclusion limits at the 95% confidence level are derived for the production cross section of a generic Higgs boson φ as a function of the Higgs boson mass and for A/H/h production in the Minimal Supersymmetric Standard Model (MSSM) as a function of the parameters mA and tanβ. © 2011 CERN.

Cover page: Search for neutral MSSM Higgs bosons decaying to τ+τ− pairs in proton–proton collisions at s=7 TeV with the ATLAS detector

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Search for supersymmetry in final states with jets, missing transverse momentum and one isolated lepton in s=7 TeV pp collisions using 1 fb-1 of ATLAS data

UC Irvine Previously Published Works (2012)

We present an update of a search for supersymmetry in final states containing jets, missing transverse momentum, and one isolated electron or muon, using 1.04fb -1 of proton-proton collision data at √s=7TeV recorded by the ATLAS experiment at the LHC in the first half of 2011. The analysis is carried out in four distinct signal regions with either three or four jets and variations on the (missing) transverse momentum cuts, resulting in optimized limits for various supersymmetry models. No excess above the standard model background expectation is observed. Limits are set on the visible cross section of new physics within the kinematic requirements of the search. The results are interpreted as limits on the parameters of the minimal supergravity framework, limits on cross sections of simplified models with specific squark and gluino decay modes, and limits on parameters of a model with bilinear R-parity violation. © 2012 CERN.

Cover page: Search for supersymmetry in final states with jets, missing transverse momentum and one isolated lepton in s=7 TeV pp collisions using 1 fb-1 of ATLAS data

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Searches for supersymmetry with the ATLAS detector using final states with two leptons and missing transverse momentum in s=7 TeV proton–proton collisions

UC Santa Cruz Previously Published Works (2012)

Results of three searches are presented for the production of supersymmetric particles decaying into final states with missing transverse momentum and exactly two isolated leptons, e or μ. The analysis uses a data sample collected during the first half of 2011 that corresponds to a total integrated luminosity of 1fb-1 of s=7TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider. Opposite-sign and same-sign dilepton events are separately studied, with no deviations from the Standard Model expectation observed. Additionally, in opposite-sign events, a search is made for an excess of same-flavour over different-flavour lepton pairs. Effective production cross sections in excess of 9.9 fb for opposite-sign events containing supersymmetric particles with missing transverse momentum greater than 250 GeV are excluded at 95% CL. For same-sign events containing supersymmetric particles with missing transverse momentum greater than 100 GeV, effective production cross sections in excess of 14.8 fb are excluded at 95% CL. The latter limit is interpreted in a simplified electroweak gaugino production model excluding chargino masses up to 200 GeV, under the assumption that slepton decay is dominant. © 2012 CERN.

Cover page: Searches for supersymmetry with the ATLAS detector using final states with two leptons and missing transverse momentum in s=7 TeV proton–proton collisions

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Electron performance measurements with the ATLAS detector using the 2010 LHC proton-proton collision data

UC Irvine Previously Published Works (2012)

Detailed measurements of the electron performance of the ATLAS detector at the LHC are reported, using decays of the Z, W and J/ψ particles. Data collected in 2010 at √s = 7 TeV are used, corresponding to an integrated luminosity of almost 40 pb-1. The inter-alignment of the inner detector and the electromagnetic calorimeter, the determination of the electron energy scale and resolution, and the performance in terms of response uniformity and linearity are discussed. The electron identification, reconstruction and trigger efficiencies, as well as the charge misidentification probability, are also presented. © 2012 CERN for the benefit of the ATLAS collaboration.

Cover page: Electron performance measurements with the ATLAS detector using the 2010 LHC proton-proton collision data

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Performance of the ATLAS Trigger System in 2010

UC Santa Cruz Previously Published Works (2012)

Proton-proton collisions at √S = 7 TeV and heavy ion collisions at √SNN = 2.76 TeV were produced by the LHC and recorded using the ATLAS experiment's trigger system in 2010. The LHC is designed with a maximum bunch crossing rate of 40 MHz and the ATLAS trigger system is designed to record approximately 200 of these per second. The trigger system selects events by rapidly identifying signatures of muon, electron, photon, tau lepton, jet, and B meson candidates, as well as using global event signatures, such as missing transverse energy. An overview of the ATLAS trigger system, the evolution of the system during 2010 and the performance of the trigger system components and selections based on the 2010 collision data are shown. A brief outline of plans for the trigger system in 2011 is presented.

Cover page: Performance of the ATLAS Trigger System in 2010

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Measurement of the W → ℓν and Z/γ* → ℓℓ production cross sections in proton-proton collisions at with the ATLAS detector

UC Davis Previously Published Works (2010)

First measurements of the W → ℓν and Z/γ * → ℓℓ (ℓ = e, μ) production cross sections in proton-proton collisions at √ s = 7TeV are presented using data recorded by the ATLAS experiment at the LHC. The results are based on 2250 W → ℓν and 179 Z/γ* → ℓℓ candidate events selected from a data set corresponding to an integrated luminosity of approximately 320 nb-1. The measured total W and Z/ γ*-boson production cross sections times the respective leptonic branching ratios for the combined electron and muon channels are σtotW · BR(W → ℓν) = 9.96 ± 0.23(stat) ± 0.50(syst) ± 1.10(lumi) nb and σtotZ/γ* · BR(Z/ γ* → ℓℓ) = 0.82 ± 0.06 (stat) ± 0.05 (syst) ± 0.09 (lumi) nb (within the invariant mass window 66 < mℓℓ < 116 GeV). The W/Z cross-section ratio is measured to be 11.7 ± 0.9(stat) ± 0.4(syst). In addition, measurements of the W+ and W- production cross sections and of the lepton charge asymmetry are reported. Theoretical predictions based on NNLO QCD calculations are found to agree with the measurements.

Cover page: Measurement of the W → ℓν and Z/γ* → ℓℓ production cross sections in proton-proton collisions at with the ATLAS detector

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Search for heavy long-lived charged particles with the ATLAS detector in pp collisions at s=7 TeV

UC Santa Cruz Previously Published Works (2011)

A search for long-lived charged particles reaching the muon spectrometer is performed using a data sample of 37 pb-1 from pp collisions at √s=7 TeV collected by the ATLAS detector at the LHC in 2010. No excess is observed above the estimated background. Stable τ̃ sleptons are excluded at 95% CL up to a mass of 136 GeV, in GMSB models with N5=3, mmessenger=250 TeV, sign(μ)=1 and tanβ=5. Electroweak production of sleptons is excluded up to a mass of 110 GeV. Gluino R-hadrons in a generic interaction model are excluded up to masses of 530 GeV to 544 GeV depending on the fraction of R-hadrons produced as g̃-balls. © 2011 CERN.

Cover page: Search for heavy long-lived charged particles with the ATLAS detector in pp collisions at s=7 TeV

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Measurement of the W charge asymmetry in the W→μν decay mode in pp collisions at s=7 TeV with the ATLAS detector

UC Santa Cruz Previously Published Works (2011)

This Letter reports a measurement of the muon charge asymmetry from W bosons produced in proton–proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS experiment at the LHC. The asymmetry is measured in the W→μν decay mode as a function of the muon pseudorapidity using a data sample corresponding to a total integrated luminosity of 31 pb−1. The results are compared to predictions based on next-to-leading order calculations with various parton distribution functions. This measurement provides information on the u and d quark momentum fractions in the proton.

Cover page: Measurement of the W charge asymmetry in the W→μν decay mode in pp collisions at s=7 TeV with the ATLAS detector

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Search for squarks and gluinos using final states with jets and missing transverse momentum with the ATLAS detector in s=7 TeV proton–proton collisions

UC Santa Cruz Previously Published Works (2011)

A search for squarks and gluinos in final states containing jets, missing transverse momentum and no electrons or muons is presented. The data were recorded by the ATLAS experiment in √s=7 TeV proton-proton collisions at the Large Hadron Collider. No excess above the Standard Model background expectation was observed in 35 pb-1 of analysed data. Gluino masses below 500 GeV are excluded at the 95% confidence level in simplified models containing only squarks of the first two generations, a gluino octet and a massless neutralino. The exclusion increases to 870 GeV for equal mass squarks and gluinos. In MSUGRA/CMSSM models with tanβ=3, A0=0 and μ>0, squarks and gluinos of equal mass are excluded below 775 GeV. These are the most stringent limits to date. © 2011 CERN.