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- 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. |
- Boukhvalov, D. W., et al.
(författare)
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Electronic structure of a Mn-12 molecular magnet : Theory and experiment
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:1, s. 014419-
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Tidskriftsartikel (refereegranskat)abstract
- We used site-selective and element-specific resonant inelastic x-ray scattering (RIXS) to study the electronic structure and the electron interaction effects in the molecular magnet [Mn12O12(CH3COO)(16)(H2O)(4)]center dot 2CH(3)COOH center dot 4H(2)O, and compared the experimental data with the results of local spin density approximation +U electron structure calculations which include the on-site Coulomb interactions. We found a good agreement between theory and experiment for the Coulomb repulsion parameter U = 4 eV. In particular, the p-d band separation of 1.8 eV has been found from the RIXS spectra, which is in accordance with the calculations. Similarly, the positions of the peaks in the XPS spectra agree with the calculated densities of p and d states. Using the results of the electronic structure calculations, we determined the intramolecular exchange parameters, and used them for diagonalization of the Mn-12 spin Hamiltonian. The calculated exchanges gave the correct ground state with the total spin S = 10.
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| 4. |
- Romero, Ana, 1975, et al.
(författare)
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Interferon (IFN)-gamma-inducible protein-10: association with histological results, viral kinetics, and outcome during treatment with pegylated IFN-alpha 2a and ribavirin for chronic hepatitis C virus infection
- 2006
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Ingår i: J Infect Dis. - 0022-1899. ; 194:7, s. 895-903
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We investigated associations between interferon (IFN)-gamma-inducible protein (IP)-10 and liver histological results, viral kinetic response, and treatment outcome in patients infected with hepatitis C virus (HCV) genotypes 1-4. METHODS: Plasma IP-10 was monitored before, during, and after treatment with pegylated IFN- alpha 2a and ribavirin in 265 HCV-infected patients. RESULTS: In univariate analyses, a low baseline IP-10 level was significantly associated with low baseline viral load, rapid viral response (RVR), a sustained viral response (SVR), body mass index <25 kg/m2, and less-pronounced fibrosis, inflammation, and steatosis (for HCV genotypes other than 3). When the results of the univariate analyses were included in multivariate analyses, a low plasma IP-10 level, low baseline viral load, and genotype 2 or 3 infection were independent predictors of an RVR and SVR. IP-10 levels decreased 6 weeks into treatment and remained low in patients with an SVR. By contrast, plasma levels of IP-10 rebounded in patients who had detectable HCV RNA after the completion of treatment. Using cutoff IP-10 levels of 150 and 600 pg/mL for predicting an SVR in patients infected with HCV genotype 1 yielded a specificity and sensitivity of 81% and 95%, respectively. CONCLUSION: Baseline IP-10 levels are predictive of the response to HCV treatment.
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| 6. |
- Treebak, Jonas T, et al.
(författare)
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AMPK-mediated AS160 phosphorylation in skeletal muscle is dependent on AMPK catalytic and regulatory subunits.
- 2006
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 55:7, s. 2051-2058
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Tidskriftsartikel (refereegranskat)abstract
- AMP-activated protein kinase (AMPK) is a heterotrimeric protein that regulates glucose transport mediated by cellular stress or pharmacological agonists such as 5-aminoimidazole-4-carboxamide 1 beta-D-ribonucleoside (AICAR). AS160, a Rab GTPase-activating protein, provides a mechanism linking AMPK signaling to glucose uptake. We show that AICAR increases AMPK, acetyl-CoA carboxylase, and AS160 phosphorylation by insulin-independent mechanisms in isolated skeletal muscle. Recombinant AMPK heterotrimeric complexes (alpha 1 beta 1 gamma l and alpha 2 beta 2 gamma 1) phosphorylate AS160 in a cell-free assay. In mice deficient in AMPK signaling (alpha 2 AMPK knockout [KO], alpha 2 AMPK kinase dead [KD], and gamma 3 AMPK KO), AICAR effects on AS160 phosphorylation were severely blunted, highlighting that complexes containing alpha 2 and gamma 3 are necessary for AICAR-stimulated AS160 phosphorylation in intact skeletal muscle. Contraction-mediated AS160 phosphorylation was also impaired in alpha 2 AMPK KO and KD but not gamma 3 AMPK KO mice. Our results implicate AS160 as a downstream target of AMPK.
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