Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Measurement of the cross-section for b-jets produced in association with a Z boson at root s=7 TeV with the ATLAS detector ATLAS Collaboration

A measurement is presented of the inclusive cross-section for b-jet production in association with a Z boson in pp collisions at a centre-of-mass energy of root s = 7 TeV. The analysis uses the data sample collected by the ATLAS experiment in 2010, corresponding to an integrated luminosity of approximately 36 pb(-1). The event selection requires a Z boson decaying into high P-T electrons or muons, and at least one b-jet, identified by its displaced vertex, with transverse momentum p(T) > 25 GeV and rapidity vertical bar y vertical bar < 2.1. After subtraction of background processes, the yield is extracted from the vertex mass distribution of the candidate b-jets. The ratio of this cross-section to the inclusive Z cross-section (the average number of b-jets per Z event) is also measured. Both results are found to be in good agreement with perturbative QCD predictions at next-to-leading order

Measurement of charged-particle event shape variables in inclusive root(s)=7 TeV proton-proton interactions with the ATLAS detector

The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor, and transverse sphericity, each defined using the final-state charged particles' momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged-particle transverse momentum, charged-particle multiplicity, and summed transverse momentum is presented. Predictions from several Monte Carlo models show significant deviations from data

Perineal Metastatic Crohn's Disease: A Case Report and Review of the Literature

Metastatic Crohn's disease is an uncommon complication of Crohn's disease defined as granulomatous inflammation not contiguous with inflammatory disease in bowel. We report on the presentation and management of a 36-year-old man, who had undergone panproctocolectomy 11 years ago, with complex fistulous disease in his perineum, which demonstrated granulomas histologically after resection. We review six similar case reports. Optimal treatment would appear to be by surgical debridement

A statistical comparison of silver and SYPRO Ruby staining for proteomic analysis.

Silver staining has been the method most commonly employed for high sensitivity staining of proteins following two-dimensional gel electrophoresis. Whilst this method offers detection in the nanogram range it does have major drawbacks including a lack of linearity, nonstoichiometric staining of proteins, a lack of compatibility with the microchemical preparation of proteins for identification by mass spectrometric techniques, and a highly subjective assessment of the staining endpoint. SYPRO Ruby is a relatively new, ruthenium complex-based stain which is reported to offer advantages over silver, particularly in overcoming the limitations cited above. We describe a series of experiments where several protein staining procedures commonly employed are compared. To enable optimization of the in situ digestion procedure, a statistical approach has been undertaken. The effects of a variety of staining, digestion, and analysis protocols on the downstream processing of a test radiolabeled protein were studied. The data confirms that as well as offering sensitivity similar to silver, SYPRO Ruby staining is reproducible, linear, and offers a higher level of compatibility with the identification of proteins by mass spectrometry

Bolt’s Farm Cave System dans le Cradle of Humankind (Afrique du Sud) : un exemple d’approche multidisciplinaire dans l’étude des sites à primates fossiles

Le Cradle of Humankind en Afrique du Sud présente des sites qui sont tous classés au titre de patrimoine mondial de l’humanité par l’UNESCO depuis 1999 (Thackeray, 2016). Ces sites ont livré des restes d’hominidés et/ou de primates non-humains (Cercopithecoidea). Robert Broom est le premier à rechercher des fossiles dans le Bolt’s Farm Cave System (ou BFCS), et ceci dès 1936. Les recherches n’y deviennent régulières que depuis 2006 avec la création du HRU (Hope (Human Origins and Past Environment) Research Unit). BFCS est surtout connu pour avoir livré des restes de grands félins. Pourtant, certains fossiles de Cercopithecoidea découverts à BFCS sont des références en paléoprimatologie comme BF42 (Cercopithecoides williamsi) et BF43 (Parapapio broomi). Waypoint 160 à BFCS a livré les plus anciens restes de primate non-humain du Cradle of Humankind qui sont datés du Pliocène inférieur. Pour obtenir plus d’informations sur le contexte géologique et le paléoenvironnement, des fouilles sont menées depuis 2011 dans certains loci et viennent remplacer les prospections menées par les membres du HRU. L’enjeu est d’obtenir le maximum de données sur la paléodiversité, notamment la microfaune qui doit être extraite des brèches par des techniques de préparation à l’acide, sur les conditions de fossilisation et de préservation des fossiles, ainsi que de pouvoir replacer ces fossiles dans le temps.The Cradle of Humankind in South Africa, recognized as World Heritage by UNESCO since 1999, contains fossil sites which have yielded hominid remains and/or non-human primates (Cercopithecoidea). Robert Broom was the first to prospect for fossils at Bolt's Farm Cave System (or BFCS), and this since 1936. Research only became regular in 2006 with the creation of the HRU (Hope (Human Origins and Past Environment) Research Unit). BFCS is best known for yielding remains of large cats. Yet some fossils of Cercopithecoidea discovered at BFCS are considered to be references in palaeoprimatology: BF42 (Cercopithecoides williamsi) and BF43 (Parapapio broomi). Waypoint 160 at BFCS yielded the oldest remains of nonhuman primates in the Cradle of Humankind which are dated to the Pliocene. For more information about the geological and palaeoenvironmental context, excavations were conducted since 2011 in some loci based on the surveys carried out by members of HRU. The present challenge is to obtain the maximum amount of data concerning palaeobiodiversity, including the microfauna which must be extracted from the breccia by acid preparation techniques, study of the conditions of fossilization and the preservation of fossils, as well as the determination of the ages of the fossils

Evaluation of efficacy- versus affinity-driven agonism with biased GLP-1R ligands P5 and exendin-F1

The glucagon-like peptide-1 receptor (GLP-1R) is an important regulator of glucose homeostasis and has been successfully targeted for the treatment of type 2 diabetes. Recently described biased GLP-1R agonists with selective reductions in β-arrestin versus G protein coupling show improved metabolic actions in vivo. However, two prototypical G protein-favouring GLP-1R agonists, P5 and exendin-F1, are reported to show divergent effects on insulin secretion. In this study we aimed to resolve this discrepancy by performing a side-by-side characterisation of these two ligands across a variety of in vitro and in vivo assays. Exendin-F1 showed reduced acute efficacy versus P5 for several readouts, including recruitment of mini-G proteins, G protein-coupled receptor kinases (GRKs) and β-arrestin-2. Maximal responses were also lower for both GLP-1R internalisation and the presence of active GLP-1R-mini-Gs complexes in early endosomes with exendin-F1 treatment. In contrast, prolonged insulin secretion in vitro and sustained anti-hyperglycaemic efficacy in mice were both greater with exendin-F1 than with P5. We conclude that the particularly low acute efficacy of exendin-F1 and associated reductions in GLP-1R downregulation appear to be more important than preservation of endosomal signalling to allow sustained insulin secretion responses. This has implications for the ongoing development of affinity- versus efficacy-driven biased GLP-1R agonists as treatments for metabolic disease