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- 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. |
- 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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| 3. |
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| 4. |
- Guo, Songchang, et al.
(författare)
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Origin of mitochondrial DNA diversity of domestic yaks
- 2006
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Background: The domestication of plants and animals was extremely important anthropologically. Previous studies have revealed a general tendency for populations of livestock species to include deeply divergent maternal lineages, indicating that they were domesticated in multiple, independent events from genetically discrete wild populations. However, in water buffalo, there are suggestions that a similar deep maternal bifurcation may have originated from a single population. These hypotheses have rarely been rigorously tested because of a lack of sufficient wild samples. To investigate the origin of the domestic yak (Poephagus grunnies), we analyzed 637 bp of maternal inherited mtDNA from 13 wild yaks (including eight wild yaks from a small population in west Qinghai) and 250 domesticated yaks from major herding regions. Results: The domestic yak populations had two deeply divergent phylogenetic groups with a divergence time of > 100,000 yrs BP. We here show that haplotypes clustering with two deeply divergent maternal lineages in domesticated yaks occur in a single, small, wild population. This finding suggests that all domestic yaks are derived from a single wild gene pool. However, there is no clear correlation of the mtDNA phylogenetic clades and the 10 morphological types of sampled yaks indicating that the latter diversified recently. Relatively high diversity was found in Qinghai and Tibet around the current wild distribution, in accordance with previous suggestions that the earliest domestications occurred in this region. Conventional molecular clock estimation led to an unrealistic early dating of the start of the domestication. However, Bayesian estimation of the coalescence time allowing a relaxation of the mutation rate Conclusion: The information gathered here and the previous studies of other animals show that the demographic histories of domestication of livestock species were highly diverse despite the common general feature of deeply divergent maternal lineages. The results further suggest that domestication of local wild prey ungulate animals was a common occurrence during the development of human civilization following the postglacial colonization in different locations of the world, including the high, arid Qinghai-Tibetan Plateau.
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| 5. |
- Xiao, Huan, et al.
(författare)
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THE STUDY FOR FERROMAGNETIC PROPERTIES AND MICROSTRUCTURE OF Bi(0.9)Ho(0.1)FeO(3)
- 2008
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Ingår i: PROCEEDINGS OF THE 2008 SYMPOSIUM ON PIEZOELECTRICITY, ACOUSTIC WAVES AND DEVICE APPLICATIONS. - : IEEE. - 9781424428915 ; , s. 557-560
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Konferensbidrag (refereegranskat)abstract
- Bi(0.9)Ho(0.1)FeO(3) ceramic is prepared by sol-gel method. We investigated the effect of Ho element doping in the BiFeO(3). We studied the microstructure, morphology and ferromagnetism for Bi(0.9)Ho(0.1)FeO(3) ceramic by XRD, SEM and SQUID. It shows that Bi(0.9)Ho(0.1)FeO(3) ceramic exhibits single phase of perovskite structure. The c/a rate is elevated from 1 to 1.009 with respect to BiFeO(3). The grains of Bi(0.9)Ho(0.1)FeO(3) ceramic shrink sharply compared with the ones of BiFeO(3) ceramic, which is beneficial to the connection between grains and the density. Bi(0.9)Ho(0.1)FeO(3) ceramic exhibits obvious ferromagnetism while BiFeO(3) ceramic does not possess the macroscopic ferromagnetism at the RT. The magnetization sinks in the horizontal direction near the zero magnetic field. It indicates that Bi(0.9)Ho(0.1)FeO(3) ceramics do not only show obvious ferromagnetism, but also could exhibit lower magnetic hysteresis loss.
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