1,552 research outputs found
Kinase-mediated quasi-dimers of EGFR
No full textLigand-induced dimerization of the epidermal growth factor receptor (ErbB-1/EGFR) involves conformational changes that expose an extracellular dimerization interface. Subsequent alterations within the cytoplasmic kinase domain, which culminate in tyrosine phosphorylation, are less understood. Our study addressed this question by using two strategies: a chimeric receptor approach employed ErbB-3, whose defective kinase domain was replaced by the respective part of EGFR. The implanted full-length kinase, unlike its subdomains, conferred dimerization and catalysis. The data infer that the kinase function of EGFR is restrained by the carboxyl tail; once grafted distally to the ectopic tail of ErbB-3, the kinase domain acquires quasi-dimerization and activation. In an attempt to alternatively refold the cytoplasmic tail, our other approach employed kinase inhibitors. Biophysical measurements and covalent cross-linking analyses showed that inhibitors targeting the active conformation of EGFR, in contrast to a compound recognizing the inactive conformation, induce quasi-dimers in a manner similar to the chimeric ErbB-3 molecule. Collectively, these observations unveil kinase domain-mediated quasi-dimers, which are regulated by an autoinhibitory carboxyl tail. On the basis of these observations, we propose that quasi-dimers precede formation of ligand-induced, fully active dimers, which are stabilized by both extracellular and intracellular receptor-receptor interactions.-Bublil, E. M., Pines, G., Patel, G., Fruhwirth, G., Ng, T., Yosef Yarden. Kinase-mediated quasi-dimers of EGFR. FASEB J. 24, 4744-4755 (2010). www.fasebj.or
Search for neutralino pair production at root s = 189 GeV
No full textA search for pair-production of neutralinos at a LEP centre-of-mass energy of 189 GeV gave no evidence for a signal. This limits the neutralino production cross-section and excludes regions in the parameter space of the Minimal Supersymmetric Standard Model (MSSM). RI Ragazzi, Stefano/D-2463-2009; Gonzalez Caballero, Isidro/E-7354-2010; Krammer, Manfred/A-6508-2010; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; Andreazza, Attilio/E-5642-2011; Marti-Garcia, Salvador/F-3085-2011; Verzi, Valerio/B-1149-2012; branchini, paolo/A-4857-2011; Shellard, Ronald/G-4825-2012; Monge, Maria Roberta/G-9127-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-201
Economic modelling using constraint logic programming
No full textThis paper investigates the use of constraint logic programming (CLP) in economic modelling
through the design and implementation of two economic models. The first model, the Desai-
Henry model contains only linear equations while the second model, constructed by the author,
contains non-linear elements. In order to implement the second model, a non-linear constraint
solver was constructed. This was necessary because, although CLP is a very powerful
programming paradigm, currently available implementations lack any on-linear constraint
solving mechanisms
Dijet Azimuthal Decorrelations in pp Collisions at root s=7 TeV
No full textMeasurements of dijet azimuthal decorrelations in pp collisions at root s = 7 TeV using the CMS detector at the CERN LHC are presented. The analysis is based on an inclusive dijet event sample corresponding to an integrated luminosity of 2: 9 pb(-1). The results are compared to predictions from perturbative QCD calculations and various Monte Carlo event generators. The dijet azimuthal distributions are found to be sensitive to initial-state gluon radiation. RI Tinoco Mendes, Andre David/D-4314-2011; Mignerey, Alice/D-6623-2011; Ganjour, Serguei/D-8853-2011; Ruiz, Alberto/E-4473-2011; Stahl, Achim/E-8846-2011; Mertzimekis, Theodore/A-3287-2008; Hektor, Andi/G-1804-2011; Chen, Mira/F-9676-2010; Wulz, Claudia-Elisabeth/H-5657-2011; Chen, Jie/H-6210-2011; Bolton, Tim/A-7951-2012; Yang, Fan/B-2755-2012; Krammer, Manfred/A-6508-2010; Petrushanko, Sergey/D-6880-2012; Lokhtin, Igor/D-7004-2012; Kodolova, Olga/D-7158-2012; Dudko, Lev/D-7127-2012; Katkov, Igor/E-2627-2012; Boos, Eduard/D-9748-2012; Snigirev, Alexander/D-8912-2012; Servoli, Leonello/E-6766-2012; Tomei, Thiago/E-7091-2012; Novaes, Sergio/D-3532-2012; Padula, Sandra /G-3560-2012; Flix, Josep/G-5414-2012; Fruhwirth, Rudolf/H-2529-2012; Azzi, Patrizia/H-5404-2012; Torassa, Ezio/I-1788-201
Robust circle reconstruction with the Riemann fit
No full textFinding and fitting circles from a set of points is a frequent problem in the data analysis of high-energy physics experiments. In a tracker immersed in a homogeneous magnetic field, tracks are close to perfect circles if projected to the bending plane. In a ring-imaging Cherenkov (RICH) detector, circles of photons around the crossing point of charged particles have to be found and their radii estimated. In both cases, non-negligible background may be present that tends to complicate the pattern recognition and to bias the circle fit. In this contribution we present a robust circle fit based on a modified Riemann fit that removes or significantly reduces the effect of background points. As in the standard Riemann fit, the measured points are projected to the Riemann sphere or paraboloid, and a plane is fitted to the projected points. The fit is made robust by replacing the usual least-squares regression by a least median of squares (LMS) regression. Because of the high breakdown point of the LMS estimator, the fit is insensitive to background points. The LMS plane is used to initialize the weights of an M-estimator that refits the plane in order to suppress eventual remaining outliers and to obtain the final circle parameters. The method is demonstrated on three sets of artificial data: points on a circle plus a comparable number of background points; points on two overlapping circles with additional background; and points obtained by the simulation of tracks in a drift chamber with mirror points and additional background. The results show high circle finding efficiency and small contamination of the final fitted circles.publishedVersionContent from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI
Measurement of the Inclusive Jet Cross Section in pp Collisions at root s=7 TeV
No full textThe inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeV at the Large Hadron Collider using the CMS experiment. The data sample corresponds to an integrated luminosity of 34 pb(-1). The measurement is made for jet transverse momenta in the range 18-1100 GeV and for absolute values of rapidity less than 3. The measured cross section extends to the highest values of jet p(T) ever observed and, within the experimental and theoretical uncertainties, is generally in agreement with next-to-leading-order perturbative QCD predictions. RI Hektor, Andi/G-1804-2011; Wulz, Claudia-Elisabeth/H-5657-2011; Chen, Jie/H-6210-2011; Bolton, Tim/A-7951-2012; Krammer, Manfred/A-6508-2010; Tinoco Mendes, Andre David/D-4314-2011; Petrushanko, Sergey/D-6880-2012; Lokhtin, Igor/D-7004-2012; Kodolova, Olga/D-7158-2012; Dudko, Lev/D-7127-2012; Perfilov, Maxim/E-1064-2012; Belyaev, Andrey/E-1540-2012; Katkov, Igor/E-2627-2012; Boos, Eduard/D-9748-2012; Snigirev, Alexander/D-8912-2012; Tomei, Thiago/E-7091-2012; Focardi, Ettore/E-7376-2012; Raidal, Martti/F-4436-2012; Novaes, Sergio/D-3532-2012; Padula, Sandra /G-3560-2012; Flix, Josep/G-5414-2012; Fruhwirth, Rudolf/H-2529-2012; Torassa, Ezio/I-1788-201
Bayesian mixture models: Theory and methods
No full textThis chapter presents some aspects of Bayesian inference in the context of mixture models. It describes the asymptotic behaviour of the corresponding posterior distributions and explores proposals to construct non-informative or vaguely informative priors in mixture models with a known number of components. The chapter analyses the mixture models can be used for density estimation, for classification or clustering, or for parameter estimation. It also describes the asymptotic behaviour of the posterior distribution in terms of the marginal density of the observations, which is a starting point of most asymptotic analysis. The chapter provides some general results on the concentration of the posterior distribution around the true marginal density of the observations. Then all the usual asymptotic results are valid: namely, the Bernstein–von Mises theorem on the parameters, the Laplace approximation of the marginal density of the observations and 1/n convergence rates of Bayesian estimators such as posterior means.https://www.taylorfrancis.com/books/e/9780429055911/chapters/10.1201/9780429055911-
Search for the standard model Higgs boson in the decay channel H?ZZ?4l in pp collisions at s?=7??TeV
No full textA search for a Higgs boson in the four-lepton decay channel H -> ZZ, with each Z boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range of 110 100 GeV (with 13 below 160 GeV), while 67.1 +/- 6.0 (9.5 +/- 1.3) events are expected from background. The four-lepton mass distribution is consistent with the expectation of standard model background production of ZZ pairs. Upper limits at 95% confidence level exclude the standard model Higgs boson in the ranges of 134-158 GeV, 180-305 GeV, and 340-465 GeV. Small excesses of events are observed around masses of 119, 126, and 320 GeV, making the observed limits weaker than expected in the absence of a signal. RI Savrin, Victor/D-6213-2012; Petrushanko, Sergey/D-6880-2012; Lokhtin, Igor/D-7004-2012; Kodolova, Olga/D-7158-2012; Dudko, Lev/D-7127-2012; Perfilov, Maxim/E-1064-2012; Belyaev, Andrey/E-1540-2012; Katkov, Igor/E-2627-2012; Boos, Eduard/D-9748-2012; Snigirev, Alexander/D-8912-2012; Tomei, Thiago/E-7091-2012; Focardi, Ettore/E-7376-2012; Raidal, Martti/F-4436-2012; Novaes, Sergio/D-3532-2012; Padula, Sandra /G-3560-2012; Lujan Center, LANL/G-4896-2012; Tinoco Mendes, Andre David/D-4314-2011; Flix, Josep/G-5414-2012; Fruhwirth, Rudolf/H-2529-2012; Chen, Jie/H-6210-2011; Torassa, Ezio/I-1788-201
Measurement of the Drell-Yan cross section in pp collisions at s?=7s=7 TeV
No full textThe Drell-Yan differential cross section is measured in pp collisions at root s = 7 TeV, from a data sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 36 pb(-1). The cross section measurement, normalized to the measured cross section in the Z region, is reported for both the dimuon and dielectron channels in the dilepton invariant mass range 15-600 GeV. The normalized cross section values are quoted both in the full phase space and within the detector acceptance. The effect of final state radiation is also identified. The results are found to agree with theoretical predictions. RI Bolton, Tim/A-7951-2012; Stahl, Achim/E-8846-2011; Krammer, Manfred/A-6508-2010; Tinoco Mendes, Andre David/D-4314-2011; Petrushanko, Sergey/D-6880-2012; Lokhtin, Igor/D-7004-2012; Kodolova, Olga/D-7158-2012; Dudko, Lev/D-7127-2012; Perfilov, Maxim/E-1064-2012; Belyaev, Andrey/E-1540-2012; Katkov, Igor/E-2627-2012; Boos, Eduard/D-9748-2012; Snigirev, Alexander/D-8912-2012; Tomei, Thiago/E-7091-2012; Focardi, Ettore/E-7376-2012; Raidal, Martti/F-4436-2012; Novaes, Sergio/D-3532-2012; Padula, Sandra /G-3560-2012; Lujan Center, LANL/G-4896-2012; Flix, Josep/G-5414-2012; Fruhwirth, Rudolf/H-2529-2012; Azzi, Patrizia/H-5404-2012; Torassa, Ezio/I-1788-201
Measurement of A(FB)(b(b)over-bar) in hadronic Z decays using a jet charge technique
No full textThe bb forward-backward asymmetry has been determined from the average charge how measured in a sample of 3,500,000 hadronic Z decays collected with the DELPHI detector in 1992 - 1995. The measurement is performed in an enriched b (b) over bar sample selected using an impact parameter tag and results in the following values for the bl; forward-backward asymmetry: A(FB)(b (b) over bar) (89.55 GeV) = 0.068 +/- 0.016 (stat.) +/- 0.0013(syst.) A(FB)(b (b) over bar)(91.26 GeV) = 0.0982 +/- 0.0047(stat.) +/- 0.0016(syst.) A(FB)(b (b) over bar)(92.94 GeV) = 0.123 +/- 0.016 (stat.) +/- 0.0027(syst.) The b (b) over bar charge separation required for this analysis is directly measured in the b tagged sample, while the other charge separations are obtained from a fragmentation model precisely calibrated to data. The effective weak mixing angle is deduced from the measurement to be: sin(2)theta(eff)1 = 0.23186 +/- 0.00063. RI De Angelis, Alessandro/B-5372-2009; Gonzalez Caballero, Isidro/E-7354-2010; Krammer, Manfred/A-6508-2010; Muresan, Raluca-Anca/C-3725-2011; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; Marti-Garcia, Salvador/F-3085-2011; Verzi, Valerio/B-1149-2012; branchini, paolo/A-4857-2011; Shellard, Ronald/G-4825-2012; Monge, Maria Roberta/G-9127-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-201
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