Andreas Pfeiffer

Bio: Andreas Pfeiffer is an academic researcher from CERN. The author has contributed to research in topics: Large Hadron Collider & Lepton. The author has an hindex of 149, co-authored 1756 publications receiving 131080 citations. Previous affiliations of Andreas Pfeiffer include Heidelberg University & Paul Scherrer Institute.

Performance of the CMS Drift Tube Chambers with Cosmic Rays

Abstract: Studies of the performance of the CMS drift tube barrel muon system are described, with results based on data collected during the CMS Cosmic Run at Four Tesla. For most of these data, the solenoidal magnet was operated with a central field of 3.8 T. The analysis of data from 246 out of a total of 250 chambers indicates a very good muon reconstruction capability, with a coordinate resolution for a single hit of about 260 microns, and a nearly 100% efficiency for the drift tube cells. The resolution of the track direction measured in the bending plane is about 1.8 mrad, and the efficiency to reconstruct a segment in a single chamber is higher than 99%. The CMS simulation of cosmic rays reproduces well the performance of the barrel muon detector.

Opiate suppression of LH secretion involves central receptors different from those mediating opiate effects on prolactin secretion

Abstract: The involvement of mu- and kappa-opiate receptors in the regulation of LH and prolactin secretion was investigated in long-term ovariectomized rats using selective opiate receptor agonists and antagonists The mu-agonists morphine and [D-Ala2,MePhe4,Gly5-ol]-enkephalin (DAGO) suppressed LH levels in a dose-related manner The benzomorphane (-)-5,9-dimethyl-2'-hydroxy-2-(tetrahydrofurfuryl)-6,7-benzomorphan tartrate (MR 2034; a designated kappa-agonist) also suppressed LH levels, whereas another benzomorphane kappa-agonist (-)-5,9-dimethyl-2'-hydroxy-2-(2-methoxy-propyl)-6,7-benzomorphan hydrobromide (MRZ 2549) had no effect on the levels of this hormone Pretreatment with the highly selective mu-antagonist beta-funaltrexamine (beta-FNA), the fumarate methyl ester derivative of naltrexone, blocked the actions of both mu-agonists and MR 2034, indicating that opiate suppression of LH secretion is mediated by mu-receptors This was further confirmed by in-vitro studies: the KCl-induced release of LHRH from perifused hypothalami obtained from ovariectomized rats was significantly reduced by DAGO but not by MRZ 2549 Prolactin secretion was stimulated in a dose-dependent manner by both mu- and kappa-agonists The stimulation caused by morphine and DAGO was antagonized by beta-FNA, whereas that caused by the kappa-agonists MR 2034 and MZR 2549 was resistant to blockade by beta-FNA but not by naloxone (an antagonist which blocks all classes of opiate receptors when given in high doses) Thus prolactin secretion seems to be regulated by both mu- and kappa-opiate receptors, whereas the effects on LH secretion seem to involve mu-receptors only

Measurement of the production cross sections for a Z boson and one or more b jets in pp collisions at s√ = 7 TeV

Abstract: The production of a Z boson, decaying into two leptons and produced in association with one or more b jets, is studied using proton-proton collisions delivered by the LHC at a centre-of-mass energy of 7 TeV. The data were recorded in 2011 with the CMS detector and correspond to an integrated luminosity of 5 fb(−1). The Z(ll) + b-jets cross sections (where ll = μμ or ee) are measured separately for a Z boson produced with exactly one b jet and with at least two b jets. In addition, a cross section ratio is extracted for a Z boson produced with at least one b jet, relative to a Z boson produced with at least one jet. The measured cross sections are compared to various theoretical predictions, and the data favour the predictions in the five-flavour scheme, where b quarks are assumed massless. The kinematic properties of the reconstructed particles are compared with the predictions from the MadGraph event generator using the pythia parton shower simulation.

Measurement of the W-boson helicity in top-quark decays from t(t)over-bar production in lepton plus jets events in pp collisions at root s=7 TeV

Abstract: The W-boson helicity fractions in top-quark decays are measured with tt events in the lepton+jets final state, using proton-proton collisions at a centre-of-mass energy of 7 TeV, collected in 2011 with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 5.0 fb^(−1). The measured fractions of longitudinal, left-, and right-handed helicity are F_0 = 0.682 ± 0.030 (stat.) ± 0.033 (syst.), F_L = 0.310 ± 0.022 (stat.) ± 0.022 (syst.), and F_R = 0.008 ± 0.012 (stat.) ± 0.014 (syst.), consistent with the standard model predictions. The measured fractions are used to probe the existence of anomalous Wtb couplings. Exclusion limits on the real components of the anomalous couplings g_L , g_R are also derived.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Standards of Medical Care in Diabetes

Abstract: XI. STRATEGIES FOR IMPROVING DIABETES CARE D iabetes is a chronic illness that requires continuing medical care and patient self-management education to prevent acute complications and to reduce the risk of long-term complications. Diabetes care is complex and requires that many issues, beyond glycemic control, be addressed. A large body of evidence exists that supports a range of interventions to improve diabetes outcomes. These standards of care are intended to provide clinicians, patients, researchers, payors, and other interested individuals with the components of diabetes care, treatment goals, and tools to evaluate the quality of care. While individual preferences, comorbidities, and other patient factors may require modification of goals, targets that are desirable for most patients with diabetes are provided. These standards are not intended to preclude more extensive evaluation and management of the patient by other specialists as needed. For more detailed information, refer to Bode (Ed.): Medical Management of Type 1 Diabetes (1), Burant (Ed): Medical Management of Type 2 Diabetes (2), and Klingensmith (Ed): Intensive Diabetes Management (3). The recommendations included are diagnostic and therapeutic actions that are known or believed to favorably affect health outcomes of patients with diabetes. A grading system (Table 1), developed by the American Diabetes Association (ADA) and modeled after existing methods, was utilized to clarify and codify the evidence that forms the basis for the recommendations. The level of evidence that supports each recommendation is listed after each recommendation using the letters A, B, C, or E.