6,286 research outputs found
Texture, twinning and metastable "tetragonal" phase in ultrathin films of HfO<sub>2</sub> on a Si substrate
Thin HfO<sub>2</sub> films grown on the lightly oxidised surface of (100) Si wafers have been examined using dark-field transmission electron microscopy and selected area electron diffraction in plan view. The polycrystalline film has a grain size of the order of 100 nm and many of the grains show evidence of twinning on (110) and (001) planes. Diffraction studies showed that the film had a strong [110] out-of-plane texture, and that a tiny volume fraction of a metastable (possibly tetragonal) phase was retained. The reasons for the texture, twinning and the retention of the metastable phase are discussed
Decoherence suppression via environment preparation
To protect a quantum system from decoherence due to interaction with its
environment, we investigate the existence of initial states of the environment
allowing for decoherence-free evolution of the system. For models in which a
two-state system interacts with a dynamical environment, we prove that such
states exist if and only if the interaction and self-evolution Hamiltonians
share an eigenstate. If decoherence by state preparation is not possible, we
show that initial states minimizing decoherence result from a delicate
compromise between the environment and interaction dynamics.Comment: 4 pages, 2 figure
More about orbitally excited hadrons from lattice QCD
This is a second paper describing the calculation of spectroscopy for
orbitally excited states from lattice simulations of Quantum Chromodynamics.
New features include higher statistics for P-wave systems and first results for
the spectroscopy of D-wave mesons and baryons, for relatively heavy quark
masses. We parameterize the Coulomb gauge wave functions for P-wave and D-wave
systems and compare them to those of their corresponding S-wave states.Comment: 21 pages plus 14 figs, 3 include
Probing the AGN Unification Model at redshift z 3 with MUSE observations of giant Ly nebulae
A prediction of the classic active galactic nuclei (AGN) unification model is
the presence of ionisation cones with different orientations depending on the
AGN type. Confirmations of this model exist for present times, but it is less
clear in the early Universe. Here, we use the morphology of giant Ly
nebulae around AGNs at redshift z3 to probe AGN emission and therefore
the validity of the AGN unification model at this redshift. We compare the
spatial morphology of 19 nebulae previously found around type I AGNs with a new
sample of 4 Ly nebulae detected around type II AGNs. Using two
independent techniques, we find that nebulae around type II AGNs are more
asymmetric than around type I, at least at radial distances ~physical kpc
(pkpc) from the ionizing source. We conclude that the type I and type II AGNs
in our sample show evidence of different surrounding ionising geometries. This
suggests that the classical AGN unification model is also valid for
high-redshift sources. Finally, we discuss how the lack of asymmetry in the
inner parts (r30 pkpc) and the associated high values of the HeII to
Ly ratios in these regions could indicate additional sources of (hard)
ionizing radiation originating within or in proximity of the AGN host galaxies.
This work demonstrates that the morphologies of giant Ly nebulae can be
used to understand and study the geometry of high redshift AGNs on
circum-nuclear scales and it lays the foundation for future studies using much
larger statistical samples.Comment: 15 pages, 13 figures, accepted for publication in MNRA
Hadronic Annihilation Decay Rates of P-wave Heavy Quarkonia with Both Relativistic and QCD Radiative Corrections
Hadronic annihilation decay rates of P-wave heavy quarkonia are given to
next-to-leading order in both and . They include ten
nonperturbative parameters, which can be rigorously defined as the matrix
elements of color-singlet and color-octet operators in NRQCD. We expect these
papameters will be determined from lattice calculations in future.Comment: 5 Pages RevTex. The paper is withdraw
Binding characteristics of a panel of monoclonal antibodies against the ligand binding domain of the human LDLr
To obtain a panel of monoclonal antibodies (MAbs) to study the folding and conformation of the low density lipoprotein receptor (LDLr), we have generated hybridomas from LDLr-deficient mice that had been immunized with the extracellular domain of the human LDLr. The 12 MAbs were specific for the ligand binding domain of the LDLr, with individual MAbs recognizing epitopes in ligand binding repeats 1, 2, 3, 5, and 7. A subset of the MAbs failed to react with the LDLr when disulfide bonds were reduced, and one MAb, specific for an epitope that spans ligand binding repeats 1 and 2, recognized two conformational forms of the LDLr with different affinities. Antibodies specific for ligand binding repeats 3, 5, and 7 completely blocked the binding of LDL particles to the LDLr on cultured human fibroblasts, whereas MAbs with epitopes in ligand binding repeats 1 and 2 partially blocked the binding of LDL to the LDLr. These anti-LDLr MAbs will serve as useful probes for further analysis of LDLr conformation and LDLr-mediated lipoprotein binding
Anisotropic Energy Gaps of Iron-based Superconductivity from Intra-band Quasiparticle Interference in LiFeAs
If strong electron-electron interactions between neighboring Fe atoms mediate
the Cooper pairing in iron-pnictide superconductors, then specific and distinct
anisotropic superconducting energy gaps \Delta_i(k) should appear on the
different electronic bands i. Here we introduce intra-band Bogoliubov
quasiparticle scattering interference (QPI) techniques for determination of
\Delta_i(k) in such materials, focusing on LiFeAs. We identify the three
hole-like bands assigned previously as \gamma, \alpha_2 and \alpha_1, and we
determine the anisotropy, magnitude and relative orientations of their
\Delta_i(k). These measurements will advance quantitative theoretical analysis
of the mechanism of Cooper pairing in iron-based superconductivity
Gluonic and leptonic decays of heavy quarkonia and the determination of and
QCD running coupling constant and are
determined from heavy quarkonia and decays. The
decay rates of and for and
are estimated by taking into account both relativistic and QCD
radiative corrections. The decay amplitudes are derived in the Bethe-Salpeter
formalism, and the decay rates are estimated by using the meson wavefunctions
which are obtained with a QCD-inspired inter-quark potential. For the
decay we find the relativistic correction to be very large
and to severely suppress the decay rate. Using the experimental values of ratio
R_g\equiv \frac {\Gamma (V\longrightarrow 3g)}% {\Gamma (V\longrightarrow
e^{+}e^{-})}\approx 10,~32 for respectively, and the
calculated widths , we find and
. These values for the QCD running coupling
constant are substantially enhanced, as compared with the ones obtained without
relativistic corrections, and are consistent with the QCD scale parameter
. We also find that these
results are mainly due to kinematic corrections and not sensitive to the
dynamical models.Comment: 15 pages in Late
Initial cardiovascular treatment patterns during the first 90 days following an incident cardiovascular event
Aims:
The aim of this study was to investigate the initial cardiovascular prescription patterns in patients after their first cardiovascular events, and to identify factors associated with cardiovascular polypharmacy.
Methods:
This was a crossâsectional study including patients aged â„ 45 years with the first record of coronary heart disease (CHD) or stroke between 2007 and 2016 using The Health Improvement Network database. This study investigated the patterns of cardiovascular drugs prescribed during the first 90 days after the first cardiovascular events. Logistic regression was used to examine the association between patients' baseline characteristics and cardiovascular polypharmacy (â„5 cardiovascular drugs).
Results:
A total of 121,600 (59,843 CHD and 61,757 stroke) patients were included in the study. The mean age was 69.5 ± 11.9 years. The proportion of patients who were prescribed 0â1, 2â3, 4â5 drugs and â„6 drugs were 11.0%, 29.8%, 38.6% and 20.5%, respectively. Factors associated with cardiovascular polypharmacy were sex (female: OR 0.74, 95% CI 0.72â0.76 vs male), age (75â84 years old: OR 0.50, 0.47â0.53 vs 45â54 years old), smoking status (current smoking: OR 1.29, 1.15â1.24 vs never), body mass index (obesity: OR 1.38, 1.34â1.43 vs normal), deprivation status (most deprived: OR 1.09, 1.04â1.14 vs least deprived) and Charlson comorbidity index (index â„5: OR 1.25, 1.16â1.35 vs index 0).
Conclusion:
Multiple cardiovascular drugs treatment was common in patients with CVD in the UK. Highârisk factors of CVD were also associated with cardiovascular polypharmacy. Further studies are warranted to assess the impact of cardiovascular polypharmacy and its interaction on CVD recurrence and mortality
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