Analysing I/O bottlenecks in LHC data analysis on grid storage resources

We describe recent I/O testing frameworks that we have developed and applied within the UK GridPP Collaboration, the ATLAS experiment and the DPM team, for a variety of distinct purposes. These include benchmarking vendor supplied storage products, discovering scaling limits of SRM solutions, tuning of storage systems for experiment data analysis, evaluating file access protocols, and exploring I/O read patterns of experiment software and their underlying event data models. With multiple grid sites now dealing with petabytes of data, such studies are becoming essential. We describe how the tests build, and improve, on previous work and contrast how the use-cases differ. We also detail the results obtained and the implications for storage hardware, middleware and experiment software

Depleted uranium in the air during the cleanup operations at Cape Arza

Cape Arza was contaminated with depleted uranium (DU) in the air strikes of NATO aeroplanes on May 30,1999. The cleanup and decontamination of the site started in 2001. Here the results of air monitoring performed during the cleanup operations in Spring 2002. are presented. The collected air samples were analyzed by high-resolution alpha spectrometry. The obtained concentrations of airborne uranium are about ten times higher than the average value usually reported for air. The ratio of the U-234/U-238 activities indicates the presence of depleted uranium in the air during the cleanup action, due to resuspension and soil disturbance in the contaminated teritory

Increase of ribavirin dose improves sustained virological response in HCV-genotype 1 patients with a partial response to peg-interferon and ribavirin

Background and aim. In patients with chronic hepatitis C receiving Peg interferon/ribavirin (PEG-IFN/RBV) who do not achieve ≥ 2log-reduction in HCV-RNA at week 12 (null responders, NR) and in those with ≥ 2log-decrease but detectable at week 24 (partial responders, PR) the probability to achieve the sustained virological response (SVR) is almost null. The aim of this study was to investigate the efficacy of individualized schedule of progressively increased RBV doses in the setting of PEG-IFN/RBV treatment. Material and methods. PR or NR to PEG-IFN/RBV instead of discontinuing treatment were enrolled to receive increasing doses of RBV until a target theoretical concentration ([tRBV]) of ≥ 15 μmol/L (by pharmacokinetic formula based on glomerular filtration rate). HCV-RNA was assessed every 4 weeks and, if detectable, RBV dose was gradually increased until negativization. Twelve weeks later, patients with detectable HCV-RNA discontinued therapy while those with undetectable HCV-RNA continued for further 48 weeks. Results. Twenty genotype-1 patients (8 NR and 12 PR) were enrolled. After 12 weeks 9 (45%) were still HCV-RNA positive and were discontinued, while remaining 11 had undetectable HCV-RNA. One stopped treatment for side effects. Ten completed treatment. Five (all PR) achieved SVR. Side effects incidence was similar to that observed during PEG-IFN/RBV. Conclusions. In conclusion, RBV high doses, according to individualized schedule, increase SVR in PR on a similar extent to that of triple therapy but without increase of side effects. Such treatment should be considered in PR with no access or intolerant to protease inhibitors (PI)

Utility of neutrophil-to-lymphocyte ratio to identify long-term survivors among HCC patients treated with sorafenib

Sorafenib is the first multikinase inhibitor demonstrating a survival benefit for patients suffering from advanced hepatocellular carcinoma (HCC). However, 1 issue remains open: what is the factor able to predict which patients will be long survivors?In the present study, we harnessed the potential of conditional survival, aiming at estimating the probability that a patient receiving sorafenib survives for more than 3 years.The present multicentric study was conducted on a cohort of 438 HCC patients. The primary end point was conditional overall survival. Kaplan-Meier survival analysis was used to calculate conditional overall survival probabilities at 3 years.The 3-year conditional survival of patients without disease progression highlights that NLR and ECOG are the factors that most accurately predict the probability of long survival. The 3-year conditional survival of patients with disease progression showed a medium effect size for HCV status, alpha-fetoprotein and NLR at all time-points. Macro-vascular portal vein invasion, extra hepatic disease, and BCLC we have a large effect size at 6 months and a medium effect size at 12 and 24 months.Our findings support the use of baseline NLR for the identification of patients with a higher probability of long-survival. NLR should be used as a stratification factor in the forthcoming clinical trials on the drugs for the advanced HCC now in pipeline

Aging Studies for the Large Honeycomb Drift Tube System of the Outer Tracker of HERA-B

The HERA-B Outer Tracker consists of drift tubes folded from polycarbonate foil and is operated with Ar/CF4/CO2 as drift gas. The detector has to stand radiation levels which are similar to LHC conditions. The first prototypes exposed to radiation in HERA-B suffered severe radiation damage due to the development of self-sustaining currents (Malter effect). In a subsequent extended R&D program major changes to the original concept for the drift tubes (surface conductivity, drift gas, production materials) have been developed and validated for use in harsh radiation environments. In the test program various aging effects (like Malter currents, gain loss due to anode aging and etching of the anode gold surface) have been observed and cures by tuning of operation parameters have been developed.Comment: 14 pages, 6 figures, to be published in the Proceedings of the International Workshop On Aging Phenomena In Gaseous Detectors, 2-5 Oct 2001, Hamburg, German

The Outer Tracker Detector of the HERA-B Experiment. Part II: Front-End Electronics

The HERA-B Outer Tracker is a large detector with 112674 drift chamber channels. It is exposed to a particle flux of up to 2x10^5/cm^2/s thus coping with conditions similar to those expected for the LHC experiments. The front-end readout system, based on the ASD-8 chip and a customized TDC chip, is designed to fulfil the requirements on low noise, high sensitivity, rate tolerance, and high integration density. The TDC system is based on an ASIC which digitizes the time in bins of about 0.5 ns within a total of 256 bins. The chip also comprises a pipeline to store data from 128 events which is required for a deadtime-free trigger and data acquisition system. We report on the development, installation, and commissioning of the front-end electronics, including the grounding and noise suppression schemes, and discuss its performance in the HERA-B experiment

Open and Hidden Charm Production in 920 GeV Proton-Nucleus Collisions

The HERA-B collaboration has studied the production of charmonium and open charm states in collisions of 920 GeV protons with wire targets of different materials. The acceptance of the HERA-B spectrometer covers negative values of xF up to xF=-0.3 and a broad range in transverse momentum from 0.0 to 4.8 GeV/c. The studies presented in this paper include J/psi differential distributions and the suppression of J/psi production in nuclear media. Furthermore, production cross sections and cross section ratios for open charm mesons are discussed.Comment: 5 pages, 9 figures, to be published in the proceedings of the 6th International Conference on Hyperons, Charm & Beauty Hadrons (BEACH04), Chicago, IL, June 27 - July 3, 200

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Search for the Flavor-Changing Neutral Current Decay D0→μ+μ−D^0 \to \mu^+\mu^- with the HERA-B Detector

We report on a search for the flavor-changing neutral current decay $D^0 \to \mu^+\mu^-$ using $50 \times 10^6$ events recorded with a dimuon trigger in interactions of 920 GeV protons with nuclei by the HERA-B experiment. We find no evidence for such decays and set a 90% confidence level upper limit on the branching fraction $Br(D^0 \to \mu^+\mu^-) <2.0 \times 10^{-6}$.Comment: 17 pages, 4 figures (of which 1 double), paper to be submitted to Physics Letters