| 1. |
- Abelev, Betty, et al.
(författare)
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Long-range angular correlations on the near and away side in p-Pb collisions at root S-NN=5.02 TeV
- 2013
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 719:1-3, s. 29-41
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Tidskriftsartikel (refereegranskat)abstract
- Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.
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| 2. |
- Abelev, Betty, et al.
(författare)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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| 3. |
- Abelev, Betty, et al.
(författare)
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Underlying Event measurements in pp collisions at root s=0.9 and 7 TeV with the ALICE experiment at the LHC
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.
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| 4. |
- Alazar, Abebayehu Seifu, et al.
(författare)
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Development of cutting force measurement system used in gear hobbing
- 2011
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Ingår i: Proceedings Of The ASME International Design Engineering Technical Conferences And Computers And Information In Engineering Conference, 2011, Vol 8. - : ASME Press. - 9780791854853 ; , s. 47-52
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Konferensbidrag (refereegranskat)abstract
- Increasing demands for high quality and high performance gear manufacturing are reflected in a need for a model based investigation of gear hobbing process. This paper presents the development of a system for online measurement of actual cutting force components during gear hobbing. Although there are a large number of well developed cutting force measuring systems for different machining operations available in the market, it is difficult to find a system tailored to the requirements of a gear hobbing process. Hence, a fixture containing piezoelectric dynamometer and telemetry device is developed. The fixture is designed taking the real machining circumstances into consideration. The telemetry system enables wireless measurement of cutting force while machining. Multiphysics finite element analysis and Artificial Neural Network (ANN) are used as tools for modeling, simulation, and calibration of the developed system. Final stage of this work includes conducting hobbing experiments to validate both the model and the force measurement system.
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| 5. |
- Boström, Mathias, et al.
(författare)
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Modifying the Poisson-Boltzmann Approach to Model Specific Ion Effects
- 2010
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Ingår i: Specific Ion Effects. - Singapore : World Scientific Publishing Co. Pte. Ltd.. - 9789814271578 ; , s. 293-309
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Specific ion effects are important in numerous fields of science and technology. They have been discussed for over 100 years, ever since the pioneering work done by Franz Hofmeister and his group in Prague. Over the last decades, hundreds of examples have been published and periodically explanations have been proposed. However, it is only recently that a profound understanding of the basic effects and their reasons could be achieved. Today, we are not far from a general explanation of specific ion effects. This book summarizes the main new ideas that have come up in the last ten years.In this book, the efforts of theoreticians are substantially supported by the experimental results stemming from new and exciting techniques. Both the new theoretical concepts and the experimental landmarks are collected and critically discussed by eminent scientists and well-known specialists in this field. Beyond the rigorous explanations, guidelines are given to non-specialists in order to help them understand the general rules governing specific ion effects in chemistry, biology, physics and engineering.
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| 6. |
- Koellensperger, Martin, et al.
(författare)
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Presentation, Diagnosis, and Management of Multiple System Atrophy in Europe: Final Analysis of the European Multiple System Atrophy Registry
- 2010
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Ingår i: Movement Disorders. - : Wiley. - 0885-3185. ; 25:15, s. 2604-2612
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Tidskriftsartikel (refereegranskat)abstract
- Multiple system atrophy (MSA) is a Parkinson's Disease (PD)-like alpha-synucleinopathy clinically characterized by dysautonomia, parkinsonism, cerebellar ataxia, and pyramidal signs in any combination. We aimed to determine whether the clinical presentation of MSA as well as diagnostic and therapeutic strategies differ across Europe and Israel. In 19 European MSA Study Group centres all consecutive patients with a clinical diagnosis of MSA were recruited from 2001 to 2005. A standardized minimal data set was obtained from all patients. Four-hundred thirty-seven MSA patients from 19 centres in 10 countries were included. Mean age at onset was 57.8 years; mean disease duration at inclusion was 5.8 years. According to the consensus criteria 68% were classified as parkinsonian type (MSA-P) and 32% as cerebellar type (MSA-C) (probable MSA: 72%, possible MSA: 28%). Symptomatic dysautonomia was present in almost all patients, and urinary dysfunction (83%) more common than symptomatic orthostatic hypotension (75%). Cerebellar ataxia was present in 64%, and parkinsonism in 87%, of all cases. No significant differences in the clinical presentation were observed between the participating countries. In contrast, diagnostic work up and therapeutic strategies were heterogeneous. Less than a third of patients with documented orthostatic hypotension or neurogenic bladder disturbance were receiving treatment. This largest clinical series of MSA patients reported so far shows that the disease presents uniformly across Europe. The observed differences in diagnostic and therapeutic management including lack of therapy for dysautonomia emphasize the need for future guidelines in these areas. (C) 2010 Movement Disorder Society
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| 7. |
- Wenning, Gregor K., et al.
(författare)
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The natural history of multiple system atrophy: a prospective European cohort study
- 2013
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Ingår i: Lancet Neurology. - 1474-4465. ; 12:3, s. 264-274
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Tidskriftsartikel (refereegranskat)abstract
- Background Multiple system atrophy (MSA) is a fatal and still poorly understood degenerative movement disorder that is characterised by autonomic failure, cerebellar ataxia, and parkinsonism in various combinations. Here we present the final analysis of a prospective multicentre study by the European MSA Study Group to investigate the natural history of MSA. Methods Patients with a clinical diagnosis of MSA were recruited and followed up clinically for 2 years. Vital status was ascertained 2 years after study completion. Disease progression was assessed using the unified MSA rating scale (UMSARS), a disease-specific questionnaire that enables the semiquantitative rating of autonomic and motor impairment in patients with MSA. Additional rating methods were applied to grade global disease severity, autonomic symptoms, and quality of life. Survival was calculated using a Kaplan-Meier analysis and predictors were identified in a Cox regression model. Group differences were analysed by parametric tests and non-parametric tests as appropriate. Sample size estimates were calculated using a paired two-group t test. Findings 141 patients with moderately severe disease fulfilled the consensus criteria for MSA. Mean age at symptom onset was 56.2 (SD 8.4) years. Median survival from symptom onset as determined by Kaplan-Meier analysis was 9.8 years (95% CI 8.1-11.4). The parkinsonian variant of MSA (hazard ratio [HR] 2.08,95% CI 1.09-3.97; p=0.026) and incomplete bladder emptying (HR 2.10,1.02-4.30; p=0.044) predicted shorter survival. 24-month progression rates of UMSARS activities of daily living, motor examination, and total scores were 49% (9.4 [SD 5.9]), 74% (12.9 [8.5]), and 57% (21.9 [11.9]), respectively, relative to baseline scores. Autonomic symptom scores progressed throughout the follow-up. Shorter symptom duration at baseline (OR 0.68, 0.5-0.9; p=0.006) and absent levodopa response (OR 3.4, 1.1-10.2; p=0.03) predicted rapid UMSARS progression. Sample size estimation showed that an interventional trial with 258 patients (129 per group) would be able to detect a 30% effect size in 1-year UMSARS motor examination decline rates at 80% power. Interpretation Our prospective dataset provides new insights into the evolution of MSA based on a follow-up period that exceeds that of previous studies. It also represents a useful resource for patient counselling and planning of multicentre trials.
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| 8. |
- Werner, Mathias
(författare)
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Theoretical and experimental studies of a single tooth milling process
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The industrial development of metal cutting processes in gear manufacturing aims at continuously increasing productivity, including increased tool reliability. Basically, the parameters that have an influence on the cutting processes should be known and possible to control.Gear manufacturing is highly important for the automotive industry. The prevalent manufacturing method is gear hobbing with hobs consisting of solid Powder Metallurgical High Speed Steel (PM HSS) with Physical Vapor Deposited (PVD) coatings.The hob teeth have to be reconditioned before wear reaches such levels that the gear quality becomes impaired. Such wear often results in a total breakdown of the tool. One crucial reason for this is that hobbing processes for the present often lack reliability; which makes it difficult for the gear manufacturers to predict the tool wear on the hob teeth and decide when the tool should be replaced in order to avoid severe damages. A consequence of catastrophic tool wear is that it leads to an instantaneously changed geometry of the cutting edge, which in turn implies that the machined gears do not comply with the stipulated properties on the machined gear products.A single tooth milling test (STMT) with tools of PM-HSS in a conventional milling machine has been developed in this research project, aiming at characterizing the effect of tool preparation on the type of wear mechanism. The experience and conclusions from these tests may probably be transferred to real PM-HSS hob tooling (HT). The advantages of such a test, compared to a real gear hob test, are primarily the cost reductions and time saving aspects with respect to both the design and the manufacturing of the cutting teethThe research presented in this thesis is based on experimental investigations and theoretical studies of significant parameters, i.e. the surface roughness and edge rounding, contributing to the robust and reliable design of a PM-HSS cutting tool. The research work has in addition to, the development of the milling test method, also comprised development of measuring methods and a simulation model based on the Finite Element Model (FEM).
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| 9. |
- Zeiler, Marlis, et al.
(författare)
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A Protein Epitope Signature Tag (PrEST) Library Allows SILAC-based Absolute Quantification and Multiplexed Determination of Protein Copy Numbers in Cell Lines
- 2012
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Mass spectrometry-based proteomics increasingly relies on relative or absolute quantification. In relative quantification, stable isotope based methods often allow mixing at early stages of sample preparation, whereas for absolute quantification this has generally required recombinant expression of full length, labeled protein standards. Here we make use of a very large library of Protein Epitope Signature Tags (PrESTs) that has been developed in the course of the Human Protein Atlas Project. These PrESTs are expressed recombinantly in E. coli and they consist of a short and unique region of the protein of interest as well as purification and solubility tags. We first quantify a highly purified, stable isotope labeling of amino acids in cell culture (SILAC)-labeled version of the solubility tag and use it determine the precise amount of each PrEST by its SILAC ratios. The PrESTs are then spiked into cell lysates and the SILAC ratios of PrEST peptides to peptides from endogenous target proteins yield their cellular quantities. The procedure can readily be multiplexed, as we demonstrate by simultaneously determining the copy number of 40 proteins in HeLa cells. Among the proteins analyzed, the cytoskeletal protein vimentin was found to be most abundant with 20 million copies per cell, while the transcription factor and oncogene FOS only had 6000 copies. Direct quantification of the absolute amount of single proteins is possible via a SILAC experiment in which labeled cell lysate is mixed both with the heavy labeled solubility tag and with the corresponding PrEST. The SILAC-PrEST combination allows accurate and streamlined quantification of the absolute or relative amount of proteins of interest in a wide variety of applications.
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