1,399 research outputs found

    Interrelationships Within the Bacterial Flora of the Female Genital Tract

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    Analysis of 240 consecutive vaginal swabs using the compatibility profile technique revealed that only 2 bacteria have the ability to be a sole isolate and as such a candidate to be a major aerobic regulator of the bacterial flora of the female genital tract (BFFGT). Compatibility profiles of Lactobacillus and Gardnerella vaginalis have shown that these organisms shared compatibility profiling for the majority of the normal bacterial constituents of the female genital tract. Dominance disruption appears to come from the addition of compatible co-isolates and presumed loss of numerical superiority. These phenomena appear to be the keys to reregulation of BFFGT. Lactobacillus appears to be the major regulator of both G. vaginalis and anaerobic bacteria. When additional organisms are added to the bacterial flora, they may add to or partially negate the inhibitory influence of Lactobacillus on the BFFGT. Inhibitor interrelationships appear to exist between coagulase-negative staphylococci and Staphylococcus aureus and the group B streptococci (GBS) and other beta hemolytic streptococci. Facilitating interrelationships appear to exist between S. aureus and the GBS and selected Enterobacteriaceae

    A Pediatric Diabetic Ketoacidosis Patient with Multisystem Complications and a Prolonged Course

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    The prevalence of diabetic ketoacidosis (DKA) in children with type 1 diabetes mellitus (T1DM) is 30% at the time of diagnosis.1 Cerebral edema is a rare, but life-threatening complication of DKA, occurring in only 0.3 - 1% of cases.2 Deep vein thrombosis and acute pancreatitis are other rare complications of DKA. Supraventricular tachycardia (SVT) as a complication of pediatric DKA has been reported.3 A unique case of a pediatric patient who had multiple rare complications of DKA including cerebral edema, venous thrombosis, and hypertriglyceridemia associated acute pancreatitis is presented.The SVT episode encountered during the admission was due to complications arising from a procedure and not due to DKA itself

    The debris disk host star HD 61005: a member of the Argus Association?

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    HD 61005 is a nearby young solar type star that shows a large infrared excess due to a debris disk. The disk has been recently imaged from ground and space, with indications of several components. Some characteristics of the disk suggest the presence of planetary companions around the star, that remain undetected in deep adaptive optics imaging. For a better understanding of the system we aim to refine the determination of the stellar parameters, with emphasis on the stellar age and system orientation. We used ASAS and Hipparcos photometry and FEROS spectra to determine the rotation period, radial and rotational velocity, chromospheric emission, effective temperature, and chemical composition. We find no indication of any misalignment between the star rotation axis and the disk. The standard age calibrations applied to several indicators yield an age close to that of the Pleiades (120 Myr); however the kinematic properties strongly support its membership in the younger (40 Myr) Argus association, which also includes the IC 2391 open cluster. Detailed comparison of the properties of HD 61005 and IC 2391 members shows that the characteristics of HD 61005 are compatible with membership to the Argus association, once its rather slow rotation is taken into account, because lithium and other age indicators are somewhat correlated with stellar rotation at a fixed age. We also identify systematic differences between the field and cluster population of the Argus association, which are probably selection effects, so we suggest that additional members with slower rotation and lower activity level are waiting to be identified.Comment: A&A, in press, 13 pages, 11 figure

    Observation of two new Ξb\Xi_b^- baryon resonances

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    Two structures are observed close to the kinematic threshold in the Ξb0π\Xi_b^0 \pi^- mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb1^{-1} recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content bdsbds are expected in this mass region: the spin-parity JP=12+J^P = \frac{1}{2}^+ and JP=32+J^P=\frac{3}{2}^+ states, denoted Ξb\Xi_b^{\prime -} and Ξb\Xi_b^{*-}. Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be m(Ξb)m(Ξb0)m(π)=3.653±0.018±0.006m(\Xi_b^{\prime -}) - m(\Xi_b^0) - m(\pi^{-}) = 3.653 \pm 0.018 \pm 0.006 MeV/c2/c^2, m(Ξb)m(Ξb0)m(π)=23.96±0.12±0.06m(\Xi_b^{*-}) - m(\Xi_b^0) - m(\pi^{-}) = 23.96 \pm 0.12 \pm 0.06 MeV/c2/c^2, Γ(Ξb)=1.65±0.31±0.10\Gamma(\Xi_b^{*-}) = 1.65 \pm 0.31 \pm 0.10 MeV, where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of Γ(Ξb)<0.08\Gamma(\Xi_b^{\prime -}) < 0.08 MeV at 95% confidence level. Relative production rates of these states are also reported.Comment: 17 pages, 2 figure

    Observation of J/ψpJ/\psi p resonances consistent with pentaquark states in Λb0J/ψKp{\Lambda_b^0\to J/\psi K^-p} decays

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    Observations of exotic structures in the J/ψpJ/\psi p channel, that we refer to as pentaquark-charmonium states, in Λb0J/ψKp\Lambda_b^0\to J/\psi K^- p decays are presented. The data sample corresponds to an integrated luminosity of 3/fb acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude analysis is performed on the three-body final-state that reproduces the two-body mass and angular distributions. To obtain a satisfactory fit of the structures seen in the J/ψpJ/\psi p mass spectrum, it is necessary to include two Breit-Wigner amplitudes that each describe a resonant state. The significance of each of these resonances is more than 9 standard deviations. One has a mass of 4380±8±294380\pm 8\pm 29 MeV and a width of 205±18±86205\pm 18\pm 86 MeV, while the second is narrower, with a mass of 4449.8±1.7±2.54449.8\pm 1.7\pm 2.5 MeV and a width of 39±5±1939\pm 5\pm 19 MeV. The preferred JPJ^P assignments are of opposite parity, with one state having spin 3/2 and the other 5/2.Comment: 48 pages, 18 figures including the supplementary material, v2 after referee's comments, now 19 figure

    Study of BDKπ+πB^{-}\to DK^-\pi^+\pi^- and BDππ+πB^-\to D\pi^-\pi^+\pi^- decays and determination of the CKM angle γ\gamma

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    We report a study of the suppressed BDKπ+πB^-\to DK^-\pi^+\pi^- and favored BDππ+πB^-\to D\pi^-\pi^+\pi^- decays, where the neutral DD meson is detected through its decays to the Kπ±K^{\mp}\pi^{\pm} and CP-even K+KK^+K^- and π+π\pi^+\pi^- final states. The measurement is carried out using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0~fb1^{-1}. We observe the first significant signals in the CP-even final states of the DD meson for both the suppressed BDKπ+πB^-\to DK^-\pi^+\pi^- and favored BDππ+πB^-\to D\pi^-\pi^+\pi^- modes, as well as in the doubly Cabibbo-suppressed DK+πD\to K^+\pi^- final state of the BDππ+πB^-\to D\pi^-\pi^+\pi^- decay. Evidence for the ADS suppressed decay BDKπ+πB^{-}\to DK^-\pi^+\pi^-, with DK+πD\to K^+\pi^-, is also presented. From the observed yields in the BDKπ+πB^-\to DK^-\pi^+\pi^-, BDππ+πB^-\to D\pi^-\pi^+\pi^- and their charge conjugate decay modes, we measure the value of the weak phase to be γ=(7419+20)o\gamma=(74^{+20}_{-19})^{\rm o}. This is one of the most precise single-measurement determinations of γ\gamma to date.Comment: 22 pages, 9 figures; All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-020.htm

    Measurement of the Bs0J/ψηB_{s}^{0} \rightarrow J/\psi \eta lifetime

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    Using a data set corresponding to an integrated luminosity of 3fb13 fb^{-1}, collected by the LHCb experiment in pppp collisions at centre-of-mass energies of 7 and 8 TeV, the effective lifetime in the Bs0J/ψηB^0_s \rightarrow J/\psi \eta decay mode, τeff\tau_{\textrm{eff}}, is measured to be τeff=1.479±0.034 (stat)±0.011 (syst)\tau_{\textrm{eff}} = 1.479 \pm 0.034~\textrm{(stat)} \pm 0.011 ~\textrm{(syst)} ps. Assuming CPCP conservation, τeff\tau_{\textrm{eff}} corresponds to the lifetime of the light Bs0B_s^0 mass eigenstate. This is the first measurement of the effective lifetime in this decay mode.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-017.htm

    Study of WW boson production in association with beauty and charm

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    The associated production of a WW boson with a jet originating from either a light parton or heavy-flavor quark is studied in the forward region using proton-proton collisions. The analysis uses data corresponding to integrated luminosities of 1.0 and 2.0fb12.0\,{\rm fb}^{-1} collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, respectively. The WW bosons are reconstructed using the WμνW\to\mu\nu decay and muons with a transverse momentum, pTp_{\rm T}, larger than 20 GeV in the pseudorapidity range 2.0202.0 20 GeV and 2.2<η<4.22.2 < \eta < 4.2. The sum of the muon and jet momenta must satisfy pT>20p_{\rm T} > 20 GeV. The fraction of W+W+jet events that originate from beauty and charm quarks is measured, along with the charge asymmetries of the W ⁣+ ⁣bW\!+\!b and W ⁣+ ⁣cW\!+\!c production cross-sections. The ratio of the W+W+jet to Z+Z+jet production cross-sections is also measured using the ZμμZ\to\mu\mu decay. All results are in agreement with Standard Model predictions

    Measurement of the mass and lifetime of the Ωb\Omega_b^- baryon

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    A proton-proton collision data sample, corresponding to an integrated luminosity of 3 fb1^{-1} collected by LHCb at s=7\sqrt{s}=7 and 8 TeV, is used to reconstruct 63±963\pm9 ΩbΩc0π\Omega_b^-\to\Omega_c^0\pi^-, Ωc0pKKπ+\Omega_c^0\to pK^-K^-\pi^+ decays. Using the ΞbΞc0π\Xi_b^-\to\Xi_c^0\pi^-, Ξc0pKKπ+\Xi_c^0\to pK^-K^-\pi^+ decay mode for calibration, the lifetime ratio and absolute lifetime of the Ωb\Omega_b^- baryon are measured to be \begin{align*} \frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\ \tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the uncertainties are statistical, systematic and from the calibration mode (for τΩb\tau_{\Omega_b^-} only). A measurement is also made of the mass difference, mΩbmΞbm_{\Omega_b^-}-m_{\Xi_b^-}, and the corresponding Ωb\Omega_b^- mass, which yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2. \end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm
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