| 1. |
- 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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| 2. |
- 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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| 3. |
- Dong, S., et al.
(författare)
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Surface phase separation in nanosized charge-ordered manganites
- 2007
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 90:8, s. 082508-
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Tidskriftsartikel (refereegranskat)abstract
- Recent experiments showed that the robust charge ordering in manganites can be weakened by reducing the grain size down to nanoscale. Weak ferromagnetism was evidenced in both nanoparticles and nanowires of charge-ordered manganites. To explain these observations, a phenomenological model based on surface phase separation is proposed. The relaxation of superexchange interaction on the surface layer allows formation of a ferromagnetic shell, whose thickness increases with decreasing grain size. Possible exchange bias and softening of the ferromagnetic transition in nanosized charge-ordered manganites are predicted. (c) 2007 American Institute of Physics.
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| 4. |
- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 5. |
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| 6. |
- Wang, Z. Q., et al.
(författare)
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Synthesis and magnetic properties of Pr0.57Ca0.43MnO3 nanoparticles
- 2007
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Ingår i: Materials Science & Engineering. - : Elsevier. - 0921-5107 .- 1873-4944. ; 136:1, s. 96-100
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Tidskriftsartikel (refereegranskat)abstract
- Pr0.57Ca0.43MnO3 nanoparticles with an average particle size of similar to 20 nm have been synthesized using hydrothermal method in combination with post-annealing, and characterized using X-ray diffraction, X-ray photoelectron spectrometer, high-resolution transmission electron microscopy and superconducting quantum interference device magnetometery. The results show that the hydrothermal synthesis of Pr1-xCaxMnO3 compound below 240 degrees C is difficult. The Pr0.57Ca0.43MnO3 nanoparticles obtained by annealing the hydrothermal products at 900 degrees C for 2 h present an orthorhombic perovskite structure with the same lattice as bulk Pr0.6Sr0.4MnO3. Magnetic characterization reveals that the low-temperature antiferromagnetic and charge ordering transitions identified in bulk Pr0.57Ca0.43MnO3 are completely suppressed in the nanoparticles, while a ferromagnetic transition occurs at -110 K. The spin-freezing behavior at low temperature for the Pr0.57Ca0.43MnO3 nanoparticles is demonstrated. (c) 2006 Elsevier B.V. All rights reserved.
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| 7. |
- Weijers-Dall, T D M, et al.
(författare)
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Measurements of the stopping forces for heavy ions in Ge, Ag and Au using novel 'polka-dot' detectors
- 2006
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 251:2, s. 352-360
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of the stopping forces for C-14, N-14 and O-16 ions in Ge and Au, for N-14 and F-19 ions in Ag, as well as for F-19 ions in Au have been made, respectively. A novel technique, reported recently, using PIN diodes coated directly with the stopping medium in a polka dot pattern was used. This provided a set of precise, self-consistent measurements on the same stopping medium. Results show small but significant deviations from SRIM stopping predictions and are also compared to a recently-developed empirical stopping force predictor.
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| 8. |
- Wortman, J. R., et al.
(författare)
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The 2008 update of the Aspergillus nidulans genome annotation: A community effort
- 2009
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1096-0937 .- 1087-1845. ; 46, s. S2-S13
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Tidskriftsartikel (refereegranskat)abstract
- The identification and annotation of protein-coding genes is one of the primary goals of whole-genome sequencing projects, and the accuracy of predicting the primary protein products of gene expression is vital to the interpretation of the available data and the design of downstream functional applications. Nevertheless, the comprehensive annotation of eukaryotic genomes remains a considerable challenge. Many genomes submitted to public databases, including those of major model organisms, contain significant numbers of wrong and incomplete gene predictions. We present a community-based reannotation of the Aspergillus nidulans genome with the primary goal of increasing the number and quality of protein functional assignments through the careful review of experts in the field of fungal biology. (C) 2009 Elsevier Inc. All rights reserved.
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| 9. |
- Zhang, Q., et al.
(författare)
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Climate change or variability? The case of Yellow river as indicated by extreme maximum and minimum air temperature during 1960-2004
- 2008
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Ingår i: Journal of Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 93:1-2, s. 35-43
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Tidskriftsartikel (refereegranskat)abstract
- The spatial and temporal variability of winter extreme low-temperature events and summer extreme high-temperature events was investigated using daily air temperature series (1960-2004) from 66 sites in the Yellow River basin, China, with the help of Mann-Kendall trend test method. In this study an extreme temperature event is defined by exceeding or falling below various threshold values of daily maximum and daily minimum air temperature: 90th percentile, 95th percentile for the high-temperature events, 10th percentile and 5th percentile for the low-temperature events. The analysis results indicate that: 1) significant upward trend of frequency and intensity of the high-temperature events is found in the stations in the west and north part of the Yellow River basin, but trends in most stations in the middle and lower Yellow River basin are not significant at > , 95% confidence level, 2) almost the whole Yellow River basin is dominated by the significant downward trend of frequency of the cold events. Stations featured by the increasing winter minimum temperature are also more than those featured by changing summer maximum temperature, and 3) annual warming trend in the Yellow River basin mainly results from the increase in winter minimum temperature. Significant warming in the upper reach of the Yellow River will be likely to threaten the availability of the water resource in the whole basin, which should draw certain concerns from local policy-makers and water resource management agency in the region.
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