| 1. |
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| 2. |
- Ablikim, M., et al.
(författare)
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Measurements of (XcJ)-> K+K-K+K- decays
- 2006
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
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| 3. |
- Bargholtz, Chr., et al.
(författare)
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The WASA detector facility at CELSIUS
- 2008
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 594:3, s. 339-350
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Tidskriftsartikel (refereegranskat)abstract
- The WASA 4 pi multidetector system, aimed at investigating light meson production in light ion collisions and eta meson rare decays at the CELSIUS storage ring in Uppsala is presented. A unique feature of the system is the use of hydrogen pellets as internal targets for the first time. A detailed description of the design, together with the anticipated and achieved performance parameters are given. (C) 2008 Elsevier B.V. All rights reserved.
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| 4. |
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| 5. |
- Kessler, Richard, et al.
(författare)
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First-Year Sloan Digital Sky Survey-II Supernova Results : Hubble Diagram and Cosmological Parameters
- 2009
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Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 185:1, s. 32-84
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of the Hubble diagram for 103 Type Ia supernovae (SNe) with redshifts 0.04 < z < 0.42, discovered during the first season (Fall 2005) of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. These data fill in the redshift "desert" between low- and high-redshift SN Ia surveys. Within the framework of the MLCS2K2 light-curve fitting method, we use the SDSS-II SN sample to infer the mean reddening parameter for host galaxies, RV = 2.18 ± 0.14stat ± 0.48syst, and find that the intrinsic distribution of host-galaxy extinction is well fitted by an exponential function, P(AV ) = exp(-AV /τV), with τV = 0.334 ± 0.088 mag. We combine the SDSS-II measurements with new distance estimates for published SN data from the ESSENCE survey, the Supernova Legacy Survey (SNLS), the Hubble Space Telescope (HST), and a compilation of Nearby SN Ia measurements. A new feature in our analysis is the use of detailed Monte Carlo simulations of all surveys to account for selection biases, including those from spectroscopic targeting. Combining the SN Hubble diagram with measurements of baryon acoustic oscillations from the SDSS Luminous Red Galaxy sample and with cosmic microwave background temperature anisotropy measurements from the Wilkinson Microwave Anisotropy Probe, we estimate the cosmological parameters w and ΩM, assuming a spatially flat cosmological model (FwCDM) with constant dark energy equation of state parameter, w. We also consider constraints upon ΩM and ΩΛ for a cosmological constant model (ΛCDM) with w = -1 and non-zero spatial curvature. For the FwCDM model and the combined sample of 288 SNe Ia, we find w = -0.76 ± 0.07(stat) ± 0.11(syst), ΩM = 0.307 ± 0.019(stat) ± 0.023(syst) using MLCS2K2 and w = -0.96 ± 0.06(stat) ± 0.12(syst), ΩM = 0.265 ± 0.016(stat) ± 0.025(syst) using the SALT-II fitter. We trace the discrepancy between these results to a difference in the rest-frame UV model combined with a different luminosity correction from color variations; these differences mostly affect the distance estimates for the SNLS and HST SNe. We present detailed discussions of systematic errors for both light-curve methods and find that they both show data-model discrepancies in rest-frame U band. For the SALT-II approach, we also see strong evidence for redshift-dependence of the color-luminosity parameter (β). Restricting the analysis to the 136 SNe Ia in the Nearby+SDSS-II samples, we find much better agreement between the two analysis methods but with larger uncertainties: w = -0.92 ± 0.13(stat)+0.10 -0.33(syst) for MLCS2K2 and w = -0.92 ± 0.11(stat)+0.07 -0.15 (syst) for SALT-II.
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| 6. |
- Hertz, Hans M., et al.
(författare)
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Laboratory x-ray micro imaging : Sources, optics, systems and applications
- 2009
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 186
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Tidskriftsartikel (refereegranskat)abstract
- We summarize the recent progress in laboratory-scale soft and hard x-ray micro imaging in Stockholm. Our soft x-ray work is based on liquid-jet laser-plasma sources which are combined with diffractive and multilayer optics to form laboratory x-ray microscopes. In the hard x-ray regime the imaging is based on a liquid-metal-jet electron-impact source which provides the necessary coherence to allow phase-contrast imaging with high fidelity.
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| 7. |
- Bashkanov, M., et al.
(författare)
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Measurement of the slope parameter for the η → 3π0 decay in the pp → ppη reaction
- 2007
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 76:4, s. 048201-
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Tidskriftsartikel (refereegranskat)abstract
- The CELSIUS-WASA setup is used to measure the 3π0 decay of η mesons produced in pp interactions with beam kinetic energies of 1.36 and 1.45 GeV. The efficiency-corrected Dalitz plot and density distributions for this decay are shown, together with a fit of the quadratic slope parameter α yielding α = −0.026 ± 0.010(stat) ± 0.010(syst). This value is compared to recent experimental results and theoretical predictions.
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| 8. |
- Bertilson, Michael C., et al.
(författare)
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Zone plate efficiency measurements with a laser-plasma source
- 2007
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Ingår i: Advances in X-Ray/EUV Optics and Components II. - : SPIE. - 9780819468536 ; , s. F7050-F7050
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Konferensbidrag (refereegranskat)abstract
- We demonstrate a compact instrument for rapid and accurate measurements of the absolute and local efficiency of soft x-ray zone plates in the water window [M. Bertilson, et al, Rev. Sci. Instrum 78, 026103 (2007)]. The arrangement is based on a new single-line lambda = 2.88 nm liquid-nitrogen-jet laser-plasma source. The versatility of the instrument enables micro and condenser zone plates with focal lengths in the range from similar to 200 mu m to similar to 100 mm to be measured. We demonstrate an accurate local efficiency map of a in-house fabricated micro zone plate. Furthermore, we show how this compact instrument allows rapid feedback to the fabrication process which is important for future improvements.
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| 9. |
- Coletti, C., et al.
(författare)
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Surface studies of hydrogen etched 3C-SiC(001) on Si(001)
- 2007
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 91:6, s. 061914-
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Tidskriftsartikel (refereegranskat)abstract
- Themorphology and structure of 3C-SiC(001) surfaces, grown on Si(001) andprepared via hydrogen etching, are studied using atomic force microscopy(AFM), low-energy electron diffraction (LEED), and Auger electron spectroscopy (AES).On the etched samples, flat surfaces with large terraces andatomic steps are revealed by AFM. In ultrahigh vacuum asharp LEED pattern with an approximate (5×1) periodicity is observed. AES studies reveal a “bulklike” composition up to the nearsurface region and indicate that an overlayer consisting of aweakly bound silicon oxide monolayer is present.
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| 10. |
- Lewin, Erik, et al.
(författare)
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On the origin of a third spectral component of C1s XPS-spectra for nc-TiC/a-C nanocomposite thin films
- 2008
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 202:15, s. 3563-3570
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Tidskriftsartikel (refereegranskat)abstract
- X-ray photoelectron spectroscopy (XPS) spectra of sputter-etched nc-TiC/a-C nanocomposite thin films published in literature show an extra feature of unknown origin in the C1s region. This feature is situated between the contributions of carbide and the carbon matrix. We have used high kinetic energy XPS (HIKE-XPS) on magnetron-sputtered nc-TiC/a-C thin films to show that this feature represents a third chemical environment in the nanocomposites, besides the carbide and the amorphous carbon. Our results show that component is present in as-deposited samples, and that the intensity is strongly enhanced by Ar+-ion etching. This third chemical environment may be due to interface or disorder effects. The implications of these observations on the XPS analysis of nanocomposites are discussed in the light of overlap problems for ternary carbon based systems.
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| 11. |
- Pauly, C., et al.
(författare)
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The pp→ppπππ reaction channels in the threshold region
- 2007
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 649:2-3, s. 122-127
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Tidskriftsartikel (refereegranskat)abstract
- The cross section for direct neutral and charged three pion production in pp interactions was measured at excess energies in the range 160–216 MeV. That comprises the first measurement of the pp→ppπ0π0π0 reaction and the direct comparison with the pp→ppπ+π−π0 process. The experiment was performed above the η meson production threshold and the cross section could be directly normalized to the cross section of the pp→ppη reaction, with the η decaying into 3 pions. Since the same final states are selected, the measurement has a low systematical error. The measured cross section ratio σ(pp→ppπ+π−π0)/σ(pp→ppπ0π0π0) is compared to predictions of dominance of different isobars in the intermediate state.
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| 12. |
- 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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| 13. |
- Vogt, Ulrich, et al.
(författare)
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Towards Soft X-Ray Phase-Sensitive Imaging with Diffractive Optical Elements
- 2006
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Ingår i: Proc. 8th International Conference X-ray Microscopy. ; , s. 91-93
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Konferensbidrag (refereegranskat)abstract
- In this contribution we present the first diffractive optical elements for soft x-ray differential interference contrast microscopy.Due to an improved calculation method the nanofabrication accuracy of these optics is the same as for comparable normal zoneplate optics with the same outermost zone width. Different diffractive optical elements were fabricated with outermost zone widthof 100 nm, different spot separation directions and different phase relations between the two spots. The optics were successfullyused in experiments both at the synchrotron radiation based TWINMIC microscope and at the Stockholm compact liquid-nitrogenlaser-plasma source based microscope.
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| 14. |
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| 15. |
- Hertz, Hans M., et al.
(författare)
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Laboratory X-ray micro- and nano-imaging
- 2009
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Ingår i: Frontiers in Optics (FiO) 2009. - Washington, D.C. : Optical Society of America. - 9781557528780
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Konferensbidrag (refereegranskat)abstract
- We summarize recent progress in laboratory x-ray imaging systems based on compact high-brightness liquid-jet sources, including <25 nm soft x-ray zone-plate microscopy and <10 μm (lens-free) hard x-ray phase-contrast imaging.
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| 16. |
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| 17. |
- Pertl, Leonhard, et al.
(författare)
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Exports and Productivity : Comparable Evidence for 14 Countries
- 2007
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Ingår i: Policy Research Working Papers. - New York : World Bank. - 1813-9450.
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Rapport (refereegranskat)abstract
- The authors use comparable micro level panel data for 14 countries and a set of identically specified empirical models to investigate the relationship between exports and productivity. The overall results are in line with the big picture that is by now familiar from the literature: Exporters are more productive than non-exporters when observed and unobserved heterogeneity are controlled for, and these exporter productivity premia tend to increase with the share of exports in total sales; there is strong evidence in favour of self-selection of more productive firms into export markets, but nearly no evidence in favour of the learning-by-exporting hypothesis. The authors document that the exporter premia differ considerably across countries in identically specified empirical models. In a meta-analysis of their results the authors find that countries that are more open and have more effective government report higher productivity premia. However, the level of development per se does not appear to be an explanation for the observed cross-country differences.
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