1,302 research outputs found

    Influence of the atrio-ventricular delay optimization on the intra left ventricular delay in cardiac resynchronization therapy

    Get PDF
    BACKGROUND: Cardiac Resynchronization Therapy (CRT) leads to a reduction of left-ventricular dyssynchrony and an acute and sustained hemodynamic improvement in patients with chronic heart failure. Furthermore, an optimized AV-delay leads to an improved myocardial performance in pacemaker patients. The focus of this study is to investigate the acute effect of an optimized AV-delay on parameters of dyssynchrony in CRT patients. METHOD: 11 chronic heart failure patients with CRT who were on stable medication were included in this study. The optimal AV-delay was defined according to the method of Ismer (mitral inflow and trans-oesophageal lead). Dyssynchrony was assessed echocardiographically at three different settings: AVD(OPT); AVD(OPT)-50 ms and AVD(OPT)+50 ms. Echocardiographic assessment included 2D- and M-mode echo for the assessment of volumes and hemodynamic parameters (CI, SV) and LVEF and tissue Doppler echo (strain, strain rate, Tissue Synchronisation Imaging (TSI) and myocardial velocities in the basal segments) RESULTS: The AVD(OPT )in the VDD mode (atrially triggered) was 105.5 ± 38.1 ms and the AVD(OPT )in the DDD mode (atrially paced) was 186.9 ± 52.9 ms. Intra-individually, the highest LVEF was measured at AVD(OPT). The LVEF at AVD(OPT )was significantly higher than in the AVD(OPT-50)setting (p = 0.03). However, none of the parameters of dyssynchrony changed significantly in the three settings. CONCLUSION: An optimized AV delay in CRT patients acutely leads to an improved systolic left ventricular ejection fraction without improving dyssynchrony

    A search for the decay modes B+/- to h+/- tau l

    Get PDF
    We present a search for the lepton flavor violating decay modes B+/- to h+/- tau l (h= K,pi; l= e,mu) using the BaBar data sample, which corresponds to 472 million BBbar pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and l candidates, we are able to fully determine the tau four-momentum. The resulting tau candidate mass is our main discriminant against combinatorial background. We see no evidence for B+/- to h+/- tau l decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10^-5.Comment: 15 pages, 7 figures, submitted to Phys. Rev.

    Evidence for an excess of B -> D(*) Tau Nu decays

    Get PDF
    Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) = 0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0 sigma and 2.7 sigma, respectively. Taken together, our results disagree with these expectations at the 3.4 sigma level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. We also report the observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the format of Figure 2 and included the effect of the change of the Tau polarization due to the charged Higg

    Search for the decay modes D^0 → e^+e^-, D^0 → ÎŒ^+ÎŒ^-, and D^0 → e^±Ό∓

    Get PDF
    We present searches for the rare decay modes D^0→e^+e^-, D^0→Ό^+ÎŒ^-, and D^0→e^±Ό^∓ in continuum e^+e^-→cc events recorded by the BABAR detector in a data sample that corresponds to an integrated luminosity of 468  fb^(-1). These decays are highly Glashow–Iliopoulos–Maiani suppressed but may be enhanced in several extensions of the standard model. Our observed event yields are consistent with the expected backgrounds. An excess is seen in the D^0→Ό^+ÎŒ^- channel, although the observed yield is consistent with an upward background fluctuation at the 5% level. Using the Feldman–Cousins method, we set the following 90% confidence level intervals on the branching fractions: B(D^0→e^+e^-)<1.7×10^(-7), B(D^0→Ό^+ÎŒ^-) within [0.6,8.1]×10^(-7), and B(D^0→e^±Ό^∓)<3.3×10^(-7)

    Pregnancy in the mature adult mouse does not alter the proportion of mammary epithelial stem/progenitor cells

    Get PDF
    Introduction In humans, an early full-term pregnancy reduces lifetime breast cancer risk by up to 50% whereas a later pregnancy (>35 years old) can increase lifetime risk. Several mechanisms have been suggested, including changes in levels of circulating hormones, changes in the way the breast responds to these hormones, changes in gene expression programmes which may alter susceptibility to transformation and changes to mammary stem cell numbers or behaviour. Previous studies have shown that the mammary tissue isolated from both virgin and parous mice has the ability to repopulate a cleared mammary fat pad in transplant experiments. Limited dilution transplant assays have demonstrated that early pregnancy (at 5 weeks of age) reduces stem/progenitor cell numbers in the mouse mammary epithelium by twofold. However, the effects on stem/progenitor cell numbers in the mammary epithelium of a pregnancy in older animals have not yet been tested. Methods Mice were put through a full-term pregnancy at 9 weeks of age, when the mammary epithelium is mature. The total mammary epithelium was purified from parous 7-week post-lactation and age-matched virgin mice and analysed by flow cytometry and limiting dilution cleared fat pad transplants. Results There were no significant differences in the proportions of different mammary epithelial cell populations or numbers of CD24+/Low Sca-1- CD49fHigh cells (stem cell enriched basal mammary epithelial compartment). There was no significant difference in stem/progenitor cell frequency based on limiting dilution transplants between the parous and age-matched virgin epithelium. Conclusions Although differences between parous and virgin mammary epithelium at later time points post lactation or following multiple pregnancies cannot be ruled out, there are no differences in stem/progenitor cell numbers between mammary epithelium isolated from parous animals which were mated at 9 weeks old and virgin animals. However, a recent report has suggested that animals that were mated at 5 weeks old have a twofold reduction in stem/progenitor cell numbers. This is of interest given the association between early, but not late, pregnancy and breast cancer risk reduction in humans. However, a mechanistic connection between stem cell numbers and breast cancer risk remains to be established

    Study of the reaction e^{+}e^{-} -->J/psi\pi^{+}\pi^{-} via initial-state radiation at BaBar

    Get PDF
    We study the process e+e−→J/ψπ+π−e^+e^-\to J/\psi\pi^{+}\pi^{-} with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BaBar detector at center-of-mass energies 10.58 and 10.54 GeV, and correspond to an integrated luminosity of 454 fb−1\mathrm{fb^{-1}}. We investigate the J/ψπ+π−J/\psi \pi^{+}\pi^{-} mass distribution in the region from 3.5 to 5.5 GeV/c2\mathrm{GeV/c^{2}}. Below 3.7 GeV/c2\mathrm{GeV/c^{2}} the ψ(2S)\psi(2S) signal dominates, and above 4 GeV/c2\mathrm{GeV/c^{2}} there is a significant peak due to the Y(4260). A fit to the data in the range 3.74 -- 5.50 GeV/c2\mathrm{GeV/c^{2}} yields a mass value 4244±54244 \pm 5 (stat) ±4 \pm 4 (syst)MeV/c2\mathrm{MeV/c^{2}} and a width value 114−15+16114 ^{+16}_{-15} (stat)±7 \pm 7(syst)MeV\mathrm{MeV} for this state. We do not confirm the report from the Belle collaboration of a broad structure at 4.01 GeV/c2\mathrm{GeV/c^{2}}. In addition, we investigate the π+π−\pi^{+}\pi^{-} system which results from Y(4260) decay

    Observation and study of baryonic B decays: B -> D(*) p pbar, D(*) p pbar pi, and D(*) p pbar pi pi

    Get PDF
    We present a study of ten B-meson decays to a D(*), a proton-antiproton pair, and a system of up to two pions using BaBar's data set of 455x10^6 BBbar pairs. Four of the modes (B0bar -> D0 p anti-p, B0bar -> D*0 p anti-p, B0bar -> D+ p anti-p pi-, B0bar -> D*+ p anti-p pi-) are studied with improved statistics compared to previous measurements; six of the modes (B- -> D0 p anti-p pi-, B- -> D*0 p anti-p pi-, B0bar -> D0 p anti-p pi- pi+, B0bar -> D*0 p anti-p pi- pi+, B- -> D+ p anti-p pi- pi-, B- -> D*+ p anti-p pi- pi-) are first observations. The branching fractions for 3- and 5-body decays are suppressed compared to 4-body decays. Kinematic distributions for 3-body decays show non-overlapping threshold enhancements in m(p anti-p) and m(D(*)0 p) in the Dalitz plots. For 4-body decays, m(p pi-) mass projections show a narrow peak with mass and full width of (1497.4 +- 3.0 +- 0.9) MeV/c2, and (47 +- 12 +- 4) MeV/c2, respectively, where the first (second) errors are statistical (systematic). For 5-body decays, mass projections are similar to phase space expectations. All results are preliminary.Comment: 28 pages, 90 postscript figures, submitted to LP0

    Search for rare quark-annihilation decays, B --> Ds(*) Phi

    Full text link
    We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

    Get PDF
    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  Όb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∌0) correlation that grows rapidly with increasing ÎŁETPb. A long-range “away-side” (Δϕ∌π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ÎŁETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁥2Δϕ modulation for all ÎŁETPb ranges and particle pT
    • 

    corecore