The ALICE EMCal L1 trigger first year of operation experience

The ALICE experiment at the LHC is equipped with an electromagnetic calorimeter (EMCal) designed to enhance its capabilities for jet, photon and electron measurement. In addition, the EMCal enables triggering on jets and photons with a centrality dependent energy threshold. After its commissioning in 2010, the EMCal Level 1 (L1) trigger was officially approved for physics data taking in 2011. After describing the L1 hardware and trigger algorithms, the commissioning and the first year of running experience, both in proton and heavy ion beams, are reviewed. Additionally, the upgrades to the original L1 trigger design are detailed.Comment: Proceedings of TWEPP-12, Oxford. 10 pages, 9 figure

Z0 Boson Measurement with the ALICE Central Barrel in pp collisions at 14 TeV

The possibility to detect the Z0 in the ALICE central barrel is studied via the electronic decay channel Z0->e+e-. The signal and the background are simulated with the leading order event generator PYTHIA 6. The total cross-sections are taken from NLO calculations. Based on test beam data, the electron identification performance of the Transition Radiation Detector is extrapolated to high momenta. The expected yields for minimum-bias pp collisions at 14 TeV are presented. An isolation cut on the single electron, together with a minimum transverse momentum cut, allows to obtain a clear signal. The expected background is of the order of 1 % with the main contribution coming from misidentified pions from jets.Comment: 4 pages, 3 figures, QM2008 proceeding

Direct determination of Al and Pb in waste printed circuit boards (PCB) by laser-induced breakdown spectroscopy (LIBS): Evaluation of calibration strategies and economic - environmental questions

Matrix-matching calibration (MMC), two-point calibration transfer (TP CT), one-point and multi-line calibration (OP MLC), single-sample calibration (SSC) and calibration free (CF) were evaluated in order to overcome matrix effects in laser-induced breakdown spectroscopy (LIBS). These calibration strategies were evaluated for direct determination of Al and Pb in waste printed circuit boards (PCB) using direct solids analysis by LIBS. Each strategy has limitations and advantages of its implementation, for the correction of matrix effects, so that it allows elementary determination with adequate accuracy. The MMC and CF proved to be excellent calibration strategies for the determination of strategic (Al) and toxic (Pb) elements by LIBS, with good recoveries (ranging from 80–120%) and low relative standard deviation (RSD%) values. A detailed discussion of the advantages and limitations of each of these five calibration strategies evaluated for LIBS is presented in this study. Lead concentrations in waste PCB samples are 5–12 times higher than established by Directive 2011/65/EU, and the samples analyzed contain between 3 and 55 g kg-1 Al, being an interesting economic and recycling source for this metal

A systematic review and meta-analysis of the effects of flavanol-containing tea, cocoa and apple products on body composition and blood lipids: exploring the factors responsible for variability in their efficacy

Several randomized controlled trials (RCTs) and meta-analyses support the benefits of flavanols on cardiometabolic health, but the factors affecting variability in the responses to these compounds have not been properly assessed. The objectives of this meta-analysis were to systematically collect the RCTs-based-evidence of the effects of flavanol-containing tea, cocoa and apple products on selected biomarkers of cardiometabolic risk and to explore the influence of various factors on the variability in the responses to the consumption of these products. A total of 120 RCTs were selected. Despite a high heterogeneity, the intake of the flavanol-containing products was associated using a random model with changes (reported as standardized difference in means (SDM)) in body mass index (−0.15, p < 0.001), waist circumference (−0.29, p < 0.001), total-cholesterol (−0.21, p < 0.001), LDL-cholesterol (−0.23, p < 0.001), and triacylglycerides (−0.11, p = 0.027), and with an increase of HDL-cholesterol (0.15, p = 0.005). Through subgroup analyses, we showed the influence of baseline-BMI, sex, source/form of administration, medication and country of investigation on some of the outcome measures and suggest that flavanols may be more effective in specific subgroups such as those with a BMI ≥ 25.0 kg/m2, non-medicated individuals or by specifically using tea products. This meta-analysis provides the first robust evidence of the effects induced by the consumption of flavanol-containing tea, cocoa and apple products on weight and lipid biomarkers and shows the influence of various factors that can affect their bioefficacy in humans. Of note, some of these effects are quantitatively comparable to those produced by drugs, life-style changes or other natural products. Further, RCTs in well-characterized populations are required to fully comprehend the factors affecting inter-individual responses to flavanol and thereby improve flavanols efficacy in the prevention of cardiometabolic disorders

Vector bosons in heavy-ion collisions at the LHC

Vector bosons become accessible experimental probes in heavy-ion collisions at the LHC. The capabilities of the LHC experiments to perform their measurement are outlined. The focus is given to their utility to study the possible formation and properties of the Quark Gluon Plasma (QGP) in the most central heavy-ion collisions. Their own sensitivity (if any) to the QGP is discussed. Their interest as references to observe multiple QGP sensitive probes is justified.Comment: HP2008 proceedings, to appear in Eur.Phys.J.

Direct correlation of crystal structure and optical properties in wurtzite/zinc-blende GaAs nanowire heterostructures

A novel method for the direct correlation at the nanoscale of structural and optical properties of single GaAs nanowires is reported. Nanowires consisting of 100% wurtzite and nanowires presenting zinc-blende/wurtzite polytypism are investigated by photoluminescence spectroscopy and transmission electron microscopy. The photoluminescence of wurtzite GaAs is consistent with a band gap of 1.5 eV. In the polytypic nanowires, it is shown that the regions that are predominantly composed of either zinc-blende or wurtzite phase show photoluminescence emission close to the bulk GaAs band gap, while regions composed of a nonperiodic superlattice of wurtzite and zinc-blende phases exhibit a redshift of the photoluminescence spectra as low as 1.455 eV. The dimensions of the quantum heterostructures are correlated with the light emission, allowing us to determine the band alignment between these two crystalline phases. Our first-principles electronic structure calculations within density functional theory, employing a hybrid-exchange functional, predict band offsets and effective masses in good agreement with experimental results

D meson nuclear modification factors in Pb-Pb collisions at {\surd}sNN = 2.76 TeV, measured with the ALICE detector

The ALICE experiment has measured the D meson production in pp and Pb-Pb collisions at the LHC at {\surd}s = 7 and 2.76 TeV and {\surd}sNN = 2.76 TeV respectively, via the exclusive reconstruction of hadronic decay channels. The analyses of the D0{\to}K-pi+ and D+{\to}K-pi+pi+ channels will be described and the preliminary results for the D0 and D+ nuclear modification factor will be presented.Comment: Proceedings of Quark Matter 2011 conference. 4 pages, 4 figures. The slides of the talk can be found at the link: http://indico.cern.ch/materialDisplay.py?contribId=591&sessionId=53&materialId=slides&confId=3024

Tratamiento de la escoliosis idiopática mediante artrodesis anterior e instrumentación de Zielke

—Hemos revisado 16 pacientes afectos de escoliosis toracolumbar y lumbar tratados mediante artrodesis anterior e instrumentación de Zielke. La corrección de la curva en el plano anteroposterior ha sido del 68%. La escoliosis torácica asociada se ha corregido de forma espontánea un 30%. La lordosis global final ha sido de 40°, sin embargo la instrumentación provoca un aumento de la cifosis regional de 10°. Las complicaciones de la serie han sido 3 roturas de barra, una progresión de la curva torácica y un derrame pleural.The authors showed the clinical outcome of 16 patients with thoracolumbar and lumbar curvatures treated by Zielke instrumentation and anterior fusion. The correction obtained in the primary curvature was 68%. The average correction in the compensatory thoracic curvature was 30%. The average lordosis correction at follow was 40°. However the Zielke's system lead to an increase of 10° of kyphotic at the instrumented levels. Complications included 3 browen rods, a progression of the thoracic curve and one pleural spilling