| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Aamodt, K., et al.
(författare)
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The ALICE experiment at the CERN LHC
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:S08002
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Forskningsöversikt (refereegranskat)abstract
- ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries, Its overall dimensions are 16 x 16 x 26 m(3) with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
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| 3. |
- Le Gentil, E., et al.
(författare)
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Coincidence measurement of residues and light particles in the reaction Fe-56+p at 1 GeV per nucleon with the spallation reactions setup SPALADIN
- 2008
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 100:2
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Tidskriftsartikel (refereegranskat)abstract
- The spallation of Fe-56 in collisions with hydrogen at 1A GeV has been studied in inverse kinematics with the large-aperture setup SPALADIN at GSI. Coincidences of residues with low-center-of-mass kinetic energy light particles and fragments have been measured allowing the decomposition of the total reaction cross section into the different possible deexcitation channels. Detailed information on the evolution of these deexcitation channels with excitation energy has also been obtained. The comparison of the data with predictions of several deexcitation models coupled to the INCL4 intranuclear cascade model shows that only GEMINI can reasonably account for the bulk of collected results, indicating that in a light system with no compression and little angular momentum, multifragmentation might not be necessary to explain the data.
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| 4. |
- Lukasik, J., et al.
(författare)
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Discriminant analysis and secondary-beam charge recognition
- 2008
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 587:2-3, s. 413-419
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Tidskriftsartikel (refereegranskat)abstract
- The discriminant-analysis method has been applied to optimize the exotic-beam charge recognition in a projectile fragmentation experiment. The experiment was carried out at the GSI using the fragment separator (FRS) to produce and select the relativistic secondary beams, and the ALADIN setup to measure their fragmentation products following collisions with Sn target nuclei. The beams of neutron poor isotopes around La-124 and Sn-107 were selected to study the isospin dependence of the limiting temperature of heavy nuclei by comparing with results for stable Sn-124 projectiles. A dedicated detector to measure the projectile charge upstream of the reaction target was not used, and alternative methods had to be developed. The presented method, based on the multivariate discriminant analysis, allowed to increase the efficacy of charge recognition up to about 90%, which was about 20% more than achieved with the simple scalar methods.
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| 5. |
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| 6. |
- Sollerman, J., et al.
(författare)
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Supernova 2006aj and the associated X-Ray Flash 060218
- 2006
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 454, s. 503-509
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the afterglow of the gamma-ray burst (GRB) of February 18, 2006. This is a nearby long GRB, with a very low peak energy, and is therefore classified as an X-ray Flash (XRF). XRF 060218 is clearly associated with a supernova - dubbed SN 2006aj. We present early spectra for SN 2006aj as well as optical lightcurves reaching out to 50 days past explosion. Our optical lightcurves define the rise times, the lightcurve shapes and the absolute magnitudes in the U, V and R bands, and we compare these data with data for other relevant supernovae. SN 2006aj evolved quite fast, somewhat similarly to SN 2002ap, but not as fast as SN 1994I. Our spectra show the evolution of the supernova over the peak, when the U-band portion of the spectrum rapidly fades due to extensive line blanketing. We compare to similar spectra of very energetic type Ic supernovae. Our first spectra are earlier than spectra for any other GRB-SN. The spectrum taken 12 days after burst in the rest frame is similar to somewhat later spectra of both SN 1998bw and SN 2003dh, implying a rapid early evolution. This is consistent with the fast lightcurve. From the narrow emission lines from the host galaxy we derive a redshift of z=0.0331±0.0007. This makes XRF 060218 the second closest gamma-ray burst detected. The flux of these emission lines indicate a high-excitation state, and a modest metallicity and star formation rate of the host galaxy.
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| 7. |
- Trautmann, W., et al.
(författare)
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Isotopic dependence of the caloric curve
- 2009
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Ingår i: Progress in Particle and Nuclear Physics. - : Elsevier BV. - 0146-6410. ; 62:2, s. 407-412
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Tidskriftsartikel (refereegranskat)abstract
- Isotopic effects in projectile fragmentation at relativistic energies have been studied with the ALADIN forward spectrometer at SIS. Stable and radioactive Sn and La beams with an incident energy of 600 MeV per nucleon have been used in order to explore a wide range of isotopic compositions. Chemical freeze-out temperatures are found to be nearly invariant with respect to the A/Z ratio of the produced spectator sources, consistent with predictions for expanded systems. Consequences for the proposed interpretation of chemical breakup temperatures as representing the limiting temperatures predicted by microscopic models are discussed. (C) 2009 Elsevier B.V. All rights reserved.
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| 8. |
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| 9. |
- Tsuchiya, Takafumi, et al.
(författare)
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Association of the calpain-10 gene with type 2 diabetes in Europeans: Results of pooled and meta-analyses
- 2006
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Ingår i: Molecular Genetics and Metabolism. - : Elsevier BV. - 1096-7192. ; 89:1-2, s. 174-184
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Tidskriftsartikel (refereegranskat)abstract
- We conducted pooled and meta-analyses of the association of the calpain-10 gene (CAPN10) polymorphisms SNP-43, Indel-19 and SNP-63 individually and as haplotypes with type 2 diabetes (T2D) in 3237 patients and 2935 controls of European ancestry. In the pooled analyses, the common SNP-43*G allele was associated with modest but statistically significant increased risk of T2D (odds ratio (OR) = 1.11 (95% confidence interval (0), 1.02-1.20), P = 0.01). Two haplotype combinations were associated with increased risk of T2D) (1-2-1/1-2-1, OR = 1.20 (1.03-1.41), P = 0.02; and 1-1-2/1-2-1, OR = 1.26 (1.01-1.59), P = 0.04) and one with decreased risk (1-1-1/2-2-1, OR = 0.86 (0.75-0.99), P = 0.03). The meta-analysis also showed a significant effect of the 1-2-1/1-2-1 haplogenotype on risk (OR = 1.25 (1.05-1.50), P = 0.01). However, there was evidence for heterogeneity with respect to this effect (P = 0.06). The heterogeneity appeared to be due to data sets in which the cases were selected from samples used in linkage studies of T2D. Using only the population-based case-control samples removed the heterogeneity (P = 0.89) and strengthened the evidence for association with T2D) in both the pooled (SNP-43*G, OR = 1.19 (1.07-1.32), P = 0.001; 1-2-1/1-2-1 haplogenotype, OR = 1.46 (1.19-1.78), P = 0.0003; 1-1-2/1-2-1 haplogenotype, OR = 1.52 (1.12-2.06), P = 0.007; and 1-1-1/2-2-1 haplogenotype, OR = 0.83 (0.70-0.99), P = 0.03) and the meta-analysis (SNP-43*G, OR = 1.18 (1.05-1.32), P = 0.005; 1-2-1/1-2-1 haplogenotype, OR = 1.68 (1.33-2.11), P = 0.00001). The pooled and meta-analyses as well as the linkage disequilibrium and haplotype diversity studies suggest a role for genetic variation in CAPN10 affecting risk of T2D in Europeans. (c) 2006 Elsevier Inc. All rights reserved.
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| 10. |
- Arrighi, Romanico B G, et al.
(författare)
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The immunogenic properties of protozoan glycosylphosphatidylinositols in the mosquito Anopheles gambiae.
- 2009
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Ingår i: Developmental and Comparative Immunology. - : Elsevier BV. - 0145-305X .- 1879-0089. ; 33:2, s. 216-23
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Tidskriftsartikel (refereegranskat)abstract
- In contrast to humans, mosquitoes do not have an adaptive immune response to deal with pathogens, and therefore must rely on their innate immune system to deal with invaders. This facilitates the recognition of different microbes on the basis of surface components or antigens. Such antigens have been identified in various types of microbe such as bacteria and fungi, yet none has been identified in the genus protozoa, which includes pathogens such as the malaria parasite, Plasmodium falciparum and Toxoplasma gondii. This study allowed us to test the antigenic properties of protozoan glycosylphosphatidylinositol (GPI) on the mosquito immune system. We found that both P. falciparum GPI and T. gondii GPI induce the strong expression of several antimicrobial peptides following ingestion, and that as a result of the immune response against the GPIs, the number of eggs produced by the mosquito is reduced dramatically. Such effects have been associated with malaria infected mosquitoes, but never associated with a Plasmodium specific antigen. This study demonstrates that protozoan GPIs can be considered as protozoan specific immune elicitors in mosquitoes, and that P. falciparum GPI plays a critical role in the malaria parasite manipulation of the mosquito vector to facilitate its transmission.
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