506 research outputs found

    Functional characterization of telomerase RNA variants found in patients with hematologic disorders

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    Human telomerase uses a specific cellular RNA, called hTERC, as the template to synthesize telomere repeats at chromosome ends. Approximately 10% to 15% of patients with aplastic anemia or other bone marrow failure syndromes are carriers of hTERC sequence variants whose functional significance, in most cases, is unknown. We screened 10 reported and 2 newly discovered hTERC variants from such patients and found that 10 of these negatively affected telomerase enzymatic function when they were used to reconstitute telomerase enzymatic function in human cells. Most functional deficits were due to perturbations of hTERC secondary structure and correlated well with the degrees of telomere shortening and reduced telomerase activity observed in peripheral blood lymphocytes of the representative patients. We also found no evidence of dominant-negative activity in any of the mutants. Therefore, loss of telomerase activity and of telomere maintenance resulting from inherited hTERC mutations may limit marrow stem cell renewal and predispose some patients to bone marrow failure. (Blood. 2005;105: 2332-2339

    An inclusive measurement of the photon energy spectrum in b->s gamma decays

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    We report a fully inclusive measurement of the flavour changing neutral current decay b->s gamma in the energy range 1.8 GeV < E* < 2.8 GeV, covering 95% of the total spectrum. Using 140 fb^-1 we obtain BF(b->s gamma)= 3.55 +/- 0.32 +0.30-0.31 +0.11-0.07, where the errors are statistical, systematic and from theory corrections. We also measure the first and second moments of the photon energy spectrum above 1.8 GeV and obtain = 2.292 +/- 0.026 +/- 0.034 GeV and -^2 = 0.0305 +/- 0.0074 +/- 0.0063 GeV^2, where the errors are statistical and systematic.Comment: RevTex4, 6 pages, Submitted to Phys.Rev.Lett. Replaced: added table of systematic errors. New results take into account radiative J/Psi decay

    Managing taste and odour metabolite production in drinking water reservoirs: The importance of ammonium as a key nutrient trigger

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    Taste and odour (T&O) compounds (most commonly 2-MIB and Geosmin) in drinking water are becoming an increasingly global problem for water management. Here, the trigger(s) for 2-MIB and Geosmin production were investigated in Plas Uchaf reservoir (North Wales, UK) with detailed water sample analysis between 2015 and 2016. Historical abstraction data from this reservoir and 4 reservoirs in Somerset (England, UK) were compared statistically using Self-Organising Map (SOM) analysis. In-reservoir measurements (2015–2016) revealed an 85% reduction in ammonium from the primary external loading source led to lower 2-MIB and Geosmin concentrations, with peak concentrations of 2-MIB declining from 60 to 21  ng l−1 and Geosmin declining from 140 to 18  ng l−1. No other measured water chemistry parameter showed a significant difference between years. The SOM results support the in-reservoir findings, revealing 2-MIB and Geosmin to be associated with high ammonium relative to nitrate for all 5 reservoirs. We conclude that ammonium is key for stimulating cyanobacterial productivity and production of T&O compounds. Whilst it is well understood that adequate availability of phosphorus is required for rapid growth in cyanobacteria, and hence should still be considered in management decisions, we suggest that monitoring sources and concentrations of ammonium is key for managing T&O outbreaks in drinking water reservoirs

    Measurement of K^+K^- production in two-photon collisions in the resonant-mass region

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    K^+K^- production in two-photon collisions has been studied using a large data sample of 67 fb^{-1} accumulated with the Belle detector at the KEKB asymmetric e^+e^- collider. We have measured the cross section for the process gamma gamma -> K^+ K^- for center-of-mass energies between 1.4 and 2.4 GeV, and found three new resonant structures in the energy region between 1.6 and 2.4 GeV. The angular differential cross sections have also been measured.Comment: 24 pages, 8 figures, to appear in Euro. Phys. Jour.

    Study of CP Violating Effects in Time Dependent B0(B0ˉ)D()π±B^0(\bar{B^0}) \to D^{(*)\mp}\pi^{\pm} Decays

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    We report measurements of time dependent decay rates for B0(Bˉ0)D()π±B^0(\bar{B}^0) \to D^{(*)\mp}\pi^{\pm} decays and extraction of CP violation parameters containing ϕ3\phi_3. Using fully reconstructed D()πD^{(*)}\pi events from a 140fb1140 {\rm fb}^{-1} data sample collected at the Υ(4S)\Upsilon(4S) resonance, we obtain the CP violation parameters for DπD^* \pi and DπD \pi decays, 2RD()πsin(2ϕ1+ϕ3±δD()π)2R_{D^{(*)} \pi} \sin (2\phi_1 + \phi_3 \pm \delta_{D^{(*)} \pi}), where RD()πR_{D^{(*)} \pi} is the ratio of the magnitudes of the doubly-Cabibbo-suppressed and Cabibbo-favoured amplitudes, and δD()π\delta_{D^{(*)} \pi} is the strong phase difference between them. Under the assumption of δD()π\delta_{D^{(*)} \pi} being close to either 0 or 180180^{\circ}, we obtain 2RDπsin(2ϕ1+ϕ3)=0.060±0.040(stat)±0.019(sys)|2R_{D^* \pi} \sin (2\phi_1 + \phi_3)| = 0.060 \pm 0.040(\mathrm{stat}) \pm 0.019(\mathrm{sys}) and 2RDπsin(2ϕ1+ϕ3)=0.061±0.037(stat)±0.018(sys)|2R_{D \pi} \sin (2\phi_1 + \phi_3)| = 0.061 \pm 0.037(\mathrm{stat}) \pm 0.018(\mathrm{sys}).Comment: 9 pages, 3 figures, Submitted to Physical Review Letter

    Observation of B+ to Lambda Lambdabar K+

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    We report the first observation of the charmless hyperonic B decay, B^+ --> Lambda Lambdabar K^+, using a 140 fb^-1 data sample recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+e^- collider. The measured branching fraction is B(B^+ --> Lambda Lambdabar K^+) = 2.91 ^{+0.90}_{-0.70} +/- 0.38 *10^-6 . We also perform a search for the related decay mode B^+ --> Lambda Lambdabar pi^+, but do not find a significant signal. We set a 90% confidence-level upper limit of B(B^+ --> Lambda Lambdabar pi^+) < 2.8 * 10^-6.Comment: 9 pages, 3 figures, submitted to Phys. Rev. Let

    Observation of a narrow charmonium-like state in exclusive B+ -> K+ pi+pi- J/psi decays

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    We report the observation of a narrow charmonium-like state produced in the exclusive decay process B+ -> K+ pi+pi- J/psi. This state, which decays into pi+pi- J/psi, has a mass of 3872.0+-0.6(stat)+-0.5(syst) MeV, a value that is very near the M_D + M_D* mass threshold. The results are based on an analysis of 152M B-Bbar events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The statistical significance of the signal is in excess of 10 sigma.Comment: 10 pages 4 figures, submitted to Physical Review Letter

    Evidence of B0 --> rho0 pi0

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    We present the first evidence of the decay B0 --> rho0 pi0, using 140fb^-1 of data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider. We detect a signal with a significance of 3.5 standard deviations, and measure the branching fraction to be Br(B0 ->- rho0 pi0) = (5.1 +/- 1.6(stat) +/- 0.9(syst))*10^-6.Comment: RevTex4, 5 pages, 4 figures, submitted to Phys.Rev.Let

    Measurement of Branching Fraction and CP Asymmetry in B+ ->rho+ pi0

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    We report a measurement of the branching fraction for the decay B+ρ+π0B^+ \to \rho^+\pi^0 based on a 140 fb1{\rm fb}^{-1} data sample collected with the Belle detector at the KEKB asymmetric e+ee^+e^- collider. We measure the branching fraction B(B+ρ+π0)=(13.2±2.3(stat.)1.9+1.4(sys.))×106{\cal B}(B^+ \to \rho^+\pi^0)=(13.2\pm 2.3({\rm stat.})^{+1.4}_{-1.9}({\rm sys.}))\times 10^{-6}, and the CP-violating asymmetry ACP(Bρπ0)=0.06±0.19(stat.)0.06+0.04(sys.){\cal A}_{CP}(B^\mp \to \rho^\mp\pi^0)=0.06\pm0.19({\rm stat.})^{+0.04}_{-0.06}({\rm sys.}).Comment: 5 pages, 3 figures; submitted to Phys. Rev. Let

    Measurements of the DsJD_{sJ} resonance properties

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    We report measurements of the properties of the DsJ+(2317)D_{sJ}^+(2317) and DsJ+(2457)D_{sJ}^+(2457) resonances produced in continuum e+ee^+ e^- annihilation near s=10.6GeV\sqrt{s}=10.6 \mathrm{GeV}. The analysis is based on an 86.9fb186.9 \mathrm{fb^{-1}} data sample collected %at and 60 MeV below the Υ(4S)\Upsilon(4S) resonance with with the Belle detector at KEKB. We determine the masses to be M(DsJ+(2317))=2317.2±0.5(stat)±0.9(syst)MeV/c2M(D_{sJ}^+(2317)) = 2317.2 \pm 0.5(\mathrm{stat}) \pm 0.9(\mathrm{syst}) \mathrm{MeV}/c^2 and M(DsJ+(2457))=2456.5±1.3(stat)±1.3(syst)MeV/c2M(D_{sJ}^+(2457))=2456.5 \pm 1.3(\mathrm{stat}) \pm 1.3(\mathrm{syst}) \mathrm{MeV}/c^2. We observe the radiative decay mode DsJ+(2457)Ds+γD_{sJ}^+(2457) \to D_s^+ \gamma and the dipion decay mode DsJ+(2457)Ds+π+πD_{sJ}^+(2457) \to D_s^+ \pi^+ \pi^-, and determine their branching fractions. No corresponding decays are observed for the DsJ(2317)D_{sJ}(2317) state. These results are consistent with the spin-parity assignments of 0+0^+ for the DsJ(2317)D_{sJ}(2317) and 1+1^+ for the DsJ(2457)D_{sJ}(2457).Comment: 5 pages, 6 figures; Added content, updated and paper submitted to PR
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