1,035 research outputs found

    Langlands duality for representations of quantum groups

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    We establish a correspondence (or duality) between the characters and the crystal bases of finite-dimensional representations of quantum groups associated to Langlands dual semi-simple Lie algebras. This duality may also be stated purely in terms of semi-simple Lie algebras. To explain this duality, we introduce an "interpolating quantum group" depending on two parameters which interpolates between a quantum group and its Langlands dual. We construct examples of its representations, depending on two parameters, which interpolate between representations of two Langlands dual quantum groups.Comment: 37 pages. References added. Accepted for publication in Mathematische Annale

    Raman-scattering study of the InGaN alloy over the whole composition range

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    We present Raman-scattering measurements on InxGa1−xN over the entire composition range of the alloy. The frequencies of the A1(LO) and E2 modes are reported and show a good agreement with the one-mode behavior dispersion predicted by the modified random-element isodisplacement model. The A1(LO) mode displays a high intensity relative to the E2 mode due to resonant enhancement. For above band-gap excitation, the A1(LO) peak displays frequency shifts as a function of the excitation energy due to selective excitation of regions with different In contents, and strong multiphonon scattering up to 3LO is observed in outgoing resonance conditions

    Structural and optical properties of MOCVD AllnN epilayers

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    7] M.-Y. Ryu, C.Q. Chen, E. Kuokstis, J.W. Yang, G. Simin, M. Asif Khan, Appl. Phys. Lett. 80 (2002) 3730. [8] D. Xu, Y. Wang, H. Yang, L. Zheng, J. Li, L. Duan, R. Wu, Sci. China (a) 42 (1999) 517. [9] H. Hirayama, A. Kinoshita, A. Hirata, Y. Aoyagi, Phys. Stat. Sol. (a) 188 (2001) 83. [10] Y. Chen, T. Takeuchi, H. Amano, I. Akasaki, N. Yamada, Y. Kaneko, S.Y. Wang, Appl. Phys. Lett. 72 (1998) 710. [11] Ig-Hyeon Kim, Hyeong-Soo Park, Yong-Jo Park, Taeil Kim, Appl. Phys. Lett. 73 (1998) 1634. [12] K. Watanabe, J.R. Yang, S.Y. Huang, K. Inoke, J.T. Hsu, R.C. Tu, T. Yamazaki, N. Nakanishi, M. Shiojiri, Appl. Phys. Lett. 82 (2003) 718

    MAF1 is a chronic repressor of RNA polymerase III transcription in the mouse.

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    Maf1 <sup>-/-</sup> mice are lean, obesity-resistant and metabolically inefficient. Their increased energy expenditure is thought to be driven by a futile RNA cycle that reprograms metabolism to meet an increased demand for nucleotides stemming from the deregulation of RNA polymerase (pol) III transcription. Metabolic changes consistent with this model have been reported in both fasted and refed mice, however the impact of the fasting-refeeding-cycle on pol III function has not been examined. Here we show that changes in pol III occupancy in the liver of fasted versus refed wild-type mice are largely confined to low and intermediate occupancy genes; high occupancy genes are unchanged. However, in Maf1 <sup>-/-</sup> mice, pol III occupancy of the vast majority of active loci in liver and the levels of specific precursor tRNAs in this tissue and other organs are higher than wild-type in both fasted and refed conditions. Thus, MAF1 functions as a chronic repressor of active pol III loci and can modulate transcription under different conditions. Our findings support the futile RNA cycle hypothesis, elaborate the mechanism of pol III repression by MAF1 and demonstrate a modest effect of MAF1 on global translation via reduced mRNA levels and translation efficiencies for several ribosomal proteins

    New polymorphic microsatellite markers for California sea lions (Zalophus californianus)

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    Nine microsatellite loci were isolated and characterized from California sea lions (Zalophus californianus). In addition, two of five loci tested from harbour seal (Phoca vitulina) produced a single, clear band in Z. californianus, as did one out of five loci from grey seal (Halichoerus grypus) and one out of two loci from elephant seal (Mirounga sp.). No locus tested from South American fur seal (Arctocephalus australis) amplified in Z. californianus. Locus variability was assessed in California sea lions from Los Islotes rookery, Baja California Sur, Mexico. All loci were variable, with allele numbers ranging from three to 12. © 2005 Blackwell Publishing Ltd.Peer Reviewe

    Cost-effectiveness of percutaneous coronary intervention with cobalt-chromium everolimus eluting stents versus bare metal stents: Results from a patient level meta-analysis of randomized trials

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    Background: Second-generation drug eluting stents (DES) may reduce costs and improve clinical outcomes compared to first-generation DES with improved cost-effectiveness when compared to bare metal stents (BMS). We aimed to conduct an economic evaluation of a cobalt-chromium everolimus eluting stent (Co-Cr EES) compared with BMS in percutaneous coronary intervention (PCI). Objective: To conduct a cost-effectiveness analysis (CEA) of a cobalt-chromium everolimus eluting stent (Co-Cr EES) versus BMS in PCI. Methods: A Markov state transition model with a 2-year time horizon was applied from a US Medicare setting with patients undergoing PCI with Co-Cr EES or BMS. Baseline characteristics, treatment effects, and safety measures were taken from a patient level meta-analysis of 5 RCTs (n=4,896). The base-case analysis evaluated stent-related outcomes; a secondary analysis considered the broader set of outcomes reported in the meta-analysis. Results: The base-case and secondary analyses reported an additional 0.018 and 0.013 quality-adjusted life years (QALYs) and cost savings of 236and236 and 288, respectively with Co-Cr EES versus BMS. Results were robust to sensitivity analyses and were most sensitive to the price of clopidogrel. In the probabilistic sensitivity analysis, Co-Cr EES was associated with a greater than 99% chance of being cost savin

    Loss of the RNA polymerase III repressor MAF1 confers obesity resistance.

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    MAF1 is a global repressor of RNA polymerase III transcription that regulates the expression of highly abundant noncoding RNAs in response to nutrient availability and cellular stress. Thus, MAF1 function is thought to be important for metabolic economy. Here we show that a whole-body knockout of Maf1 in mice confers resistance to diet-induced obesity and nonalcoholic fatty liver disease by reducing food intake and increasing metabolic inefficiency. Energy expenditure in Maf1(-/-) mice is increased by several mechanisms. Precursor tRNA synthesis was increased in multiple tissues without significant effects on mature tRNA levels, implying increased turnover in a futile tRNA cycle. Elevated futile cycling of hepatic lipids was also observed. Metabolite profiling of the liver and skeletal muscle revealed elevated levels of many amino acids and spermidine, which links the induction of autophagy in Maf1(-/-) mice with their extended life span. The increase in spermidine was accompanied by reduced levels of nicotinamide N-methyltransferase, which promotes polyamine synthesis, enables nicotinamide salvage to regenerate NAD(+), and is associated with obesity resistance. Consistent with this, NAD(+) levels were increased in muscle. The importance of MAF1 for metabolic economy reveals the potential for MAF1 modulators to protect against obesity and its harmful consequences

    Study of the D^0 \to pi^-pi^+pi^-pi^+ decay

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    Using data from the FOCUS (E831) experiment at Fermilab, we present new measurements for the Cabibbo-suppressed decay mode D0ππ+ππ+D^0 \to \pi^-\pi^+\pi^-\pi^+. We measure the branching ratio Γ(D0π+ππ+π)/Γ(D0Kπ+ππ+)=0.0914±0.0018±0.0022\Gamma(D^0 \to\pi^+\pi^- \pi^+\pi^-)/\Gamma(D^0 \to K^-\pi^+\pi^-\pi^+) = 0.0914 \pm 0.0018 \pm 0.0022. An amplitude analysis has been performed, a first for this channel, in order to determine the resonant substructure of this decay mode. The dominant component is the decay D0a1(1260)+πD^0 \to a_1(1260)^+ \pi^-, accounting for 60% of the decay rate. The second most dominant contribution comes from the decay D0ρ(770)0ρ(770)0D^0 \to \rho(770)^0\rho(770)^0, with a fraction of 25%. We also study the a1(1260)a_1(1260) line shape and resonant substructure. Using the helicity formalism for the angular distribution of the decay D0ρ(770)0ρ(770)0D^0 \to \rho(770)^0\rho(770)^0, we measure a longitudinal polarization of PL=(71±4±2)P_L = (71 \pm 4\pm 2)%.Comment: 38 pages, 8 figures. accepted for publication in Physical Review

    Search for Λc+pK+π\Lambda_c^+ \to p K^+ \pi^- and Ds+K+K+πD_s^+ \to K^+ K^+ \pi^- Using Genetic Programming Event Selection

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    We apply a genetic programming technique to search for the double Cabibbo suppressed decays Λc+pK+π\Lambda_c^+ \to p K^+ \pi^- and Ds+K+K+πD_s^+ \to K^+ K^+ \pi^-. We normalize these decays to their Cabibbo favored partners and find BR(\text{BR}(\Lambda_c^+ \to p K^+ \pi^-)/BR()/\text{BR}(\Lambda_c^+ \to p K^- \pi^+)=(0.05±0.26±0.02)) = (0.05 \pm 0.26 \pm 0.02)% and BR(\text{BR}(D_s^+ \to K^+ K^+ \pi^-)/BR()/\text{BR}(D_s^+ \to K^+ K^- \pi^+)=(0.52±0.17±0.11)) = (0.52\pm 0.17\pm 0.11)% where the first errors are statistical and the second are systematic. Expressed as 90% confidence levels (CL), we find <0.46< 0.46 % and <0.78 < 0.78% respectively. This is the first successful use of genetic programming in a high energy physics data analysis.Comment: 10 page
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