1,243 research outputs found
Time invariance violating nuclear electric octupole moments
The existence of a nuclear electric octupole moment (EOM) requires both
parity and time invariance violation. The EOMs of odd nuclei that are
induced by a particular T- and P-odd interaction are calculated. We compare
such octupole moments with the collective EOMs that can occur in nuclei having
a static octupole deformation. A nuclear EOM can induce a parity and time
invariance violating atomic electric dipole moment, and the magnitude of this
effect is calculated. The contribution of a nuclear EOM to such a dipole moment
is found, in most cases, to be smaller than that of other mechanisms of atomic
electric dipole moment production.Comment: Uses RevTex, 25 page
Stability, resolution, and ultra-low wear amplitude modulation atomic force microscopy of DNA: Small amplitude small set-point imaging
A way to operate fundamental mode amplitude modulation atomic force microscopy is introduced which optimizes stability and resolution for a given tip size and shows negligible tip wear over extended time periods (∼24 h). In small amplitude small set-point (SASS) imaging, the cantilever oscillates with sub-nanometer amplitudes in the proximity of the sample, without the requirement of using large drive forces, as the dynamics smoothly lead the tip to the surface through the water layer. SASS is demonstrated on single molecules of double-stranded DNA in ambient conditions where sharp silicon tips (R ∼ 2-5 nm) can resolve the right-handed double helix
Time-reversal violating rotation of polarization plane of light in gas placed in electric field
Rotation of polarization plane of light in gas placed in electric field is
considered. Different factors causing this phenomenon are investigated. Angle
of polarization plane rotation for transition 6S_{1/2} - 7S_{1/2} in cesium
(lambda=539 nm) is estimated. The possibility to observe this effect
experimentally is discussed.Comment: 10 pages, Late
Direct CP, T and/or CPT violations in the K^0-\bar{K^0} system - Implications of the recent KTeV results on decays -
The recent results on the CP violating parameters Re(e'/e) and \Delta\phi =
\phi_{00}-\phi_{+-} reported by the KTeV Collaboration are analyzed with a view
to constrain CP, T and CPT violations in a decay process. Combining with some
relevant data compiled by the Particle Data Group, we find Re(e_2-e_0) = (0.85
+- 3.11)*10^{-4} and Im(e_2-e_0) = (3.2 +- 0.7)*10^{-4}, where Re(e_I) and
Im(e_I) represent respectively CP/CPT and CP/T violations in decay of K^0 and
\bar{K^0} into a 2\pi state with isospin I.Comment: 7 pages, No figure
Testing of CP, CPT and causality violation with the light propagation in vacuum in presence of the uniform electric and magnetic fields
We have considered the structure of the fundamental symmetry violating part
of the photon refractive index in vacuum in the presence of constant electric
and magnetic fields. This part of the refractive index can, in principle,
contain CPT symmetry breaking terms. Some of the terms violate Lorentz
invariance, whereas the others violate locality and causality. Estimates of
these effects, using laser experiments are considered.Comment: 12 page
Analogue Models for T and CPT Violation in Neutral-Meson Oscillations
Analogue models for CP violation in neutral-meson systems are studied in a
general framework. No-go results are obtained for models in classical mechanics
that are nondissipative or that involve one-dimensional oscillators. A complete
emulation is shown to be possible for a two-dimensional oscillator with
rheonomic constraints, and an explicit example with spontaneous T and CPT
violation is presented. The results have implications for analogue models with
electrical circuits.Comment: 9 page
The sputum transcriptome better predicts COPD exacerbations after the withdrawal of inhaled corticosteroids than sputum eosinophils.
Introduction: Continuing inhaled corticosteroid (ICS) use does not benefit all patients with COPD, yet it is difficult to determine which patients may safely sustain ICS withdrawal. Although eosinophil levels can facilitate this decision, better biomarkers could improve personalised treatment decisions. Methods: We performed transcriptional profiling of sputum to explore the molecular biology and compared the predictive value of an unbiased gene signature versus sputum eosinophils for exacerbations after ICS withdrawal in COPD patients. RNA-sequencing data of induced sputum samples from 43 COPD patients were associated with the time to exacerbation after ICS withdrawal. Expression profiles of differentially expressed genes were summarised to create gene signatures. In addition, we built a Bayesian network model to determine coregulatory networks related to the onset of COPD exacerbations after ICS withdrawal. Results: In multivariate analyses, we identified a gene signature (LGALS12, ALOX15, CLC, IL1RL1, CD24, EMR4P) associated with the time to first exacerbation after ICS withdrawal. The addition of this gene signature to a multiple Cox regression model explained more variance of time to exacerbations compared to a model using sputum eosinophils. The gene signature correlated with sputum eosinophil as well as macrophage cell counts. The Bayesian network model identified three coregulatory gene networks as well as sex to be related to an early versus late/nonexacerbation phenotype. Conclusion: We identified a sputum gene expression signature that exhibited a higher predictive value for predicting COPD exacerbations after ICS withdrawal than sputum eosinophilia. Future studies should investigate the utility of this signature, which might enhance personalised ICS treatment in COPD patients
Order-disorder criticality, wetting, and morphological phase transitions in the irreversible growth of far-from-equilibrium magnetic films
An exhaustive numerical investigation of the growth of magnetic films in
confined -dimensional stripped geometries () is carried out by
means of extensive Monte Carlo simulations. Thin films in contact with a
thermal bath are grown by adding spins with two possible orientations and
considering ferromagnetic (nearest-neighbor) interactions. At low temperatures,
it is observed that the films exhibit ``spontaneous magnetization reversals''
during the growth process. Furthermore, it is found that for the system
is non-critical, while a continuous order-disorder phase transition at finite
temperature takes place in the case. Using standard finite-size scaling
procedures, the critical temperature and some relevant critical exponents are
determined. Finally, the growth of magnetic films in dimensions with
competing short-range magnetic fields acting along the confinement walls is
studied. Due to the antisymmetric condition considered, an interface between
domains with spins having opposite orientation develops along the growing
direction. Such an interface undergoes a localization-delocalization transition
that is the precursor of a wetting transition in the thermodynamic limit.
Furthermore, the growing interface also undergoes morphological transitions in
the growth mode. A comparison between the well-studied equilibrium Ising model
and the studied irreversible magnetic growth model is performed throughout.
Although valuable analogies are encountered, it is found that the
nonequilibrium nature of the latter introduces new and rich physical features
of interest.Comment: 23 pages, 10 figure
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