146 research outputs found
Hardening mechanism of commercially pure Mg processed by high pressure torsion at room temperature
Coarse-grained Mg in the as-cast condition and fine-grained Mg in the extruded condition were processed by high pressure torsion (HPT) at room temperature for up to 16 turns. Microstructure observation and texture analysis indicate that to fulfil the Von Mises criterion, the non-basal slip is activated in the as-cast Mg and tension twinning is activated in the as-extruded Mg. Although the deformation mechanism is different in the as-cast Mg and the as-extruded Mg during HPT, their hardening evolutions are similar, i.e. after 1/8 turn of HPT, microhardness of the as-cast Mg and the extruded Mg both show a significant increase and further HPT processing does not significantly further increase the microhardness. Texture strengthening can explain the rapid hardening. Hardness anisotropy and texture data results suggest that texture strengthening plays an important role for both types of samples. Texture strengthening weakens with decreasing grain size
Non-tuberculous mycobacteria disease pre-lung transplantation:A systematic review of the treatment regimens and duration pre- and post-transplant
Background: There is lack of consensus on non-tuberculous mycobacteria pulmonary disease (NTM-PD) treatment regimen and duration in patient listed for lung transplantation (LTx). We conducted a systematic review on treatment regimen and duration pre- and directly post-LTx, for patients with known NTM-PD pre-LTx. Additionally, we searched for risk factors for NTM disease development post-LTx and for mortality.Methods: Literature was reviewed on PubMed, Embase and the Cochrane Library, for articles published from inception to January 2022. Individual patient data were sought.Results: Sixteen studies were included reporting 92 patients. Most frequent used agents were aminoglycosides and macrolides for Mycobacterium abscessus (M. abscessus) and macrolides and tuberculostatic agents for Mycobacterium avium complex (M. avium complex). The median treatment duration pre-LTx was 10 months (IQR 6–17) and 2 months (IQR 2–8) directly post-LTx. Longer treatment duration pre-LTx was observed in children and in patients with M. abscessus. 46% of the patients with NTM-PD pre-LTx developed NTM disease post-LTx, related mortality rate was 10%. Longer treatment duration pre-LTx (p < 0.001) and sputum non-conversion pre-LTx (p = 0.003) were significantly associated with development of NTM-disease post-LTx. Longer treatment duration pre-LTx (p = 0.004), younger age (p < 0.001) and sputum non-conversion (p = 0.044) were risk factors for NTM related death.Conclusions: The median treatment duration pre-LTx was 10 months (IQR 6–17) and 2 months (IQR 2–8) directly post-LTx. Patients with longer treatment duration for NTM-PD pre-LTx and with sputum non-conversion are at risk for NTM disease post-LTx and for NTM-related death. Children were particularly at risk for NTM related death
Non-Markovian dynamics in a spin star system: The failure of thermalization
In most cases, a small system weakly interacting with a thermal bath will
finally reach the thermal state with the temperature of the bath. We show that
this intuitive picture is not always true by a spin star model where non-Markov
effect predominates in the whole dynamical process. The spin star system
consists a central spin homogeneously interacting with an ensemble of identical
noninteracting spins. We find that the correlation time of the bath is
infinite, which implies that the bath has a perfect memory, and that the
dynamical evolution of the central spin must be non- Markovian. A direct
consequence is that the final state of the central spin is not the thermal
state equilibrium with the bath, but a steady state which depends on its
initial state.Comment: 8 page
Precise predictions for the Higgs production in association with a W-boson pair at ILC
The Higgs-boson production in association with a W-boson pair at
linear colliders is one of the important processes in probing the coupling
between Higgs-boson and vector gauge bosons and discovering the signature of
new physics. We describe the impact of the complete electroweak(EW) radiative
corrections of to this process in the standard
model(SM) at the International Linear Collider(ILC), and investigate the
dependence of the lowest-order(LO) and EW next-to-leading order(NLO) corrected
cross sections on colliding energy and Higg-boson mass. The LO and
NLO EW corrected distributions of the invariant mass of W-boson pair and the
transverse momenta of final - and Higgs-boson are presented. Our numerical
results show that the relative EW radiative correction() varies
from -19.4% to 0.2% when and goes up from to
.Comment: 18 pages, 7 figure
Observation of a Narrow Resonance of Mass 2.46 GeV/c^2 Decaying to D_s^*+ pi^0 and Confirmation of the D_sJ^* (2317) State
Using 13.5 inverse fb of e+e- annihilation data collected with the CLEO II
detector we have observed a narrow resonance in the Ds*+pi0 final state, with a
mass near 2.46 GeV. The search for such a state was motivated by the recent
discovery by the BaBar Collaboration of a narrow state at 2.32 GeV, the
DsJ*(2317)+ that decays to Ds+pi0. Reconstructing the Ds+pi0 and Ds*+pi0 final
states in CLEO data, we observe peaks in both of the corresponding
reconstructed mass difference distributions, dM(Dspi0)=M(Dspi0)-M(Ds) and
dM(Ds*pi0)=M(Ds*pi0)-M(Ds*), both of them at values near 350 MeV. We interpret
these peaks as signatures of two distinct states, the DsJ*(2317)+ plus a new
state, designated as the DsJ(2463)+. Because of the similar dM values, each of
these states represents a source of background for the other if photons are
lost, ignored or added. A quantitative accounting of these reflections confirms
that both states exist. We have measured the mean mass differences
= 350.0 +/- 1.2 [stat] +/- 1.0 [syst] MeV for the DsJ*(2317) state, and
= 351.2 +/- 1.7 [stat] +/- 1.0 [syst] MeV for the new DsJ(2463)+
state. We have also searched, but find no evidence, for decays of the two
states via the channels Ds*+gamma, Ds+gamma, and Ds+pi+pi-. The observations of
the two states at 2.32 and 2.46 GeV, in the Ds+pi0 and Ds*+pi0 decay channels
respectively, are consistent with their interpretations as (c anti-strange)
mesons with orbital angular momentum L=1, and spin-parities of 0+ and 1+.Comment: 16 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, version to be published in Physical
Review D; minor modifications and fixes to typographical errors, plus an
added section on production properties. The main results are unchanged; they
supersede those reported in hep-ex/030501
Measurement of the Charge Asymmetry in
We report on a search for a CP-violating asymmetry in the charmless hadronic
decay B -> K*(892)+- pi-+, using 9.12 fb^-1 of integrated luminosity produced
at \sqrt{s}=10.58 GeV and collected with the CLEO detector. We find A_{CP}(B ->
K*(892)+- pi-+) = 0.26+0.33-0.34(stat.)+0.10-0.08(syst.), giving an allowed
interval of [-0.31,0.78] at the 90% confidence level.Comment: 7 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to PR
Study of the q^2-Dependence of B --> pi ell nu and B --> rho(omega)ell nu Decay and Extraction of |V_ub|
We report on determinations of |Vub| resulting from studies of the branching
fraction and q^2 distributions in exclusive semileptonic B decays that proceed
via the b->u transition. Our data set consists of the 9.7x10^6 BBbar meson
pairs collected at the Y(4S) resonance with the CLEO II detector. We measure
B(B0 -> pi- l+ nu) = (1.33 +- 0.18 +- 0.11 +- 0.01 +- 0.07)x10^{-4} and B(B0 ->
rho- l+ nu) = (2.17 +- 0.34 +0.47/-0.54 +- 0.41 +- 0.01)x10^{-4}, where the
errors are statistical, experimental systematic, systematic due to residual
form-factor uncertainties in the signal, and systematic due to residual
form-factor uncertainties in the cross-feed modes, respectively. We also find
B(B+ -> eta l+ nu) = (0.84 +- 0.31 +- 0.16 +- 0.09)x10^{-4}, consistent with
what is expected from the B -> pi l nu mode and quark model symmetries. We
extract |Vub| using Light-Cone Sum Rules (LCSR) for 0<= q^2<16 GeV^2 and
Lattice QCD (LQCD) for 16 GeV^2 <= q^2 < q^2_max. Combining both intervals
yields |Vub| = (3.24 +- 0.22 +- 0.13 +0.55/-0.39 +- 0.09)x10^{-3}$ for pi l nu,
and |Vub| = (3.00 +- 0.21 +0.29/-0.35 +0.49/-0.38 +-0.28)x10^{-3} for rho l nu,
where the errors are statistical, experimental systematic, theoretical, and
signal form-factor shape, respectively. Our combined value from both decay
modes is |Vub| = (3.17 +- 0.17 +0.16/-0.17 +0.53/-0.39 +-0.03)x10^{-3}.Comment: 45 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to PR
Search for CP Violation in D^0--> K_S^0 pi^+pi^-
We report on a search for CP violation in the decay of D0 and D0B to Kshort
pi+pi-. The data come from an integrated luminosity of 9.0 1/fb of e+e-
collisions at sqrt(s) ~ 10 GeV recorded with the CLEO II.V detector. The
resonance substructure of this decay is well described by ten quasi-two-body
decay channels (K*-pi+, K*0(1430)-pi+, K*2(1430)-pi+, K*(1680)-pi+, Kshort rho,
Kshort omega, Kshort f0(980), Kshort f2(1270), Kshort f0(1370), and the ``wrong
sign'' K*+ pi-) plus a small non-resonant component. We observe no evidence for
CP violation in the amplitudes and phases that describe the decay D0 to K_S^0
pi+pi-.Comment: 10 pages, 3 figures, also available at
http://w4.lns.cornell.edu/public/CLNS/, submitted to PR
Measurement of Lepton Momentum Moments in the Decay bar{B} \to X \ell \bar{\nu} and Determination of Heavy Quark Expansion Parameters and |V_cb|
We measure the primary lepton momentum spectrum in B-bar to X l nu decays,
for p_l > 1.5 GeV/c in the B rest frame. From this, we calculate various
moments of the spectrum. In particular, we find R_0 = [int(E_l>1.7)
(dGam/dE_sl)*dE_l] / [int(E_l>1.5) (dGam/dE_sl)*dE_l] = 0.6187 +/- 0.0014_stat
+/- 0.0016_sys and R_1 = [int(E_l>1.5) E_l(dGam/dE_sl)*dE_l] / [int(E_l>1.5)
(dGam/dE_sl)*dE_l] = (1.7810 +/- 0.0007_stat +/- 0.0009_sys) GeV. We use these
moments to determine non-perturbative parameters governing the semileptonic
width. In particular, we extract the Heavy Quark Expansion parameters
Lambda-bar = (0.39 +/- 0.03_stat +/- 0.06_sys +/- 0.12_th) GeV and lambda_1 =
(-0.25 +/- 0.02_stat +/- 0.05_sys +/- 0.14_th) GeV^2. The theoretical
constraints used are evaluated through order 1/M_B^3 in the non-perturbative
expansion and beta_0*alpha__s^2 in the perturbative expansion. We use these
parameters to extract |V_cb| from the world average of the semileptonic width
and find |V_cb| = (40.8 +/- 0.5_Gam-sl +/- 0.4_(lambda_1,Lambda-bar)-exp +/-
0.9_th) x 10^-3. In addition, we extract the short range b-quark mass m_b^1S =
(4.82 +/- 0.07_exp +/- 0.11_th) GeV/c^2. Finally, we discuss the implications
of our measurements for the theoretical understanding of inclusive semileptonic
processes.Comment: 21 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to PR
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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