22 research outputs found
Study of the Coleman - de Luccia instanton of the second order
We study the second order Coleman - de Luccia instanton which appears as the
curvature of the effective potential reaches a sufficiently large value. We
show how one can find the approximative formula for this instanton by
perturbative expansion in the case when the second derivative of the effective
potential divided by the Hubble parameter squared is close to -10, and we
perform a numerical study of this instanton in the case of quasi-exponential
potential.Comment: three pages, one figur
Commutator Anomaly in Noncommutative Quantum Mechanics
In this letter, firstly, the Schrdinger equation on noncommutative
phase space is given by using a generalized Bopp's shift. Then the anomaly term
of commutator of arbitrary physical observable operators on noncommutative
phase space is obtained. Finally, the basic uncertainty relations for
space-space and space-momentum as well as momentum-momentum operators in
noncommutative quantum mechanics (NCQM), and uncertainty relation for arbitrary
physical observable operators in NCQM are discussed.Comment: 7 page
Coleman - de Luccia instanton of the second order in a brane world
The second order Coleman - de Luccia instanton and its action in the Randall
- Sundrum type II model are investigated and the comparison with the results in
Einstein's general relativity is done in the present paper.Comment: 4 pages, accepted in IJT
Bound state energies and phase shifts of a non-commutative well
Non-commutative quantum mechanics can be viewed as a quantum system
represented in the space of Hilbert-Schmidt operators acting on non-commutative
configuration space. Within this framework an unambiguous definition can be
given for the non-commutative well. Using this approach we compute the bound
state energies, phase shifts and scattering cross sections of the non-
commutative well. As expected the results are very close to the commutative
results when the well is large or the non-commutative parameter is small.
However, the convergence is not uniform and phase shifts at certain energies
exhibit a much stronger then expected dependence on the non-commutative
parameter even at small values.Comment: 12 pages, 8 figure
False vacuum decay in a brane world cosmological model
The false vacuum decay in a brane world model is studied in this work. We
investigate the vacuum decay via the Coleman-de Luccia instanton, derive
explicit approximative expressions for the Coleman-de Luccia instanton which is
close to a Hawking-Moss instanton and compare the results with those already
obtained within Einstein's theory of relativity.Comment: minor changes done, references added, version to appear in GR
The HMW effect in Noncommutative Quantum Mechanics
The HMW effect in non-commutative quantum mechanics is studied. By solving
the Dirac equations on non-commutative (NC) space and non-commutative phase
space, we obtain topological HMW phase on NC space and NC phase space
respectively, where the additional terms related to the space-space and
momentum-momentum non-commutativity are given explicitly.Comment: 8 Latex page
Weyl-Wigner Formulation of Noncommutative Quantum Mechanics
We address the phase space formulation of a noncommutative extension of
quantum mechanics in arbitrary dimension, displaying both spatial and momentum
noncommutativity. By resorting to a covariant generalization of the Weyl-Wigner
transform and to the Seiberg-Witten map we construct an isomorphism between the
operator and the phase space representations of the extended Heisenberg
algebra. This map provides a systematic approach to derive the entire structure
of noncommutative quantum mechanics in phase space. We construct the extended
starproduct, Moyal bracket and propose a general definition of noncommutative
states. We study the dynamical and eigenvalue equations of the theory and prove
that the entire formalism is independent of the particular choice of
Seiberg-Witten map. Our approach unifies and generalizes all the previous
proposals for the phase space formulation of noncommutative quantum mechanics.
For concreteness we rederive these proposals by restricting our formalism to
some 2-dimensional spaces.Comment: Revtex4, 3 diagrams, 32 page
False vacuum decay with gravity in a critical case
The vacuum decay in a de Sitter universe is studied within semiclassical
approximation for the class of effective inflaton potentials whose curvature at
the top is close to a critical value. By comparing the actions of the Hawking -
Moss instanton and the Coleman - de Luccia instanton(s) the mode of vacuum
decay is determined. The case when the fourth derivative of the effective
potential at its top is less than a critical value is discussed.Comment: 10 pages, 8 figures, minor changes don
Noncommutative quantum mechanics and Bohm's ontological interpretation
We carry out an investigation into the possibility of developing a Bohmian
interpretation based on the continuous motion of point particles for
noncommutative quantum mechanics. The conditions for such an interpretation to
be consistent are determined, and the implications of its adoption for
noncommutativity are discussed. A Bohmian analysis of the noncommutative
harmonic oscillator is carried out in detail. By studying the particle motion
in the oscillator orbits, we show that small-scale physics can have influence
at large scales, something similar to the IR-UV mixing
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Impact of Intermediate Hyperglycemia and Diabetes on Immune Dysfunction in Tuberculosis
Supplementary Data:
Supplementary materials are available at Clinical Infectious Diseases online at https://academic.oup.com/cid/article/72/1/69/5857148#274319223 . Consisting of data provided by the authors to benefit the reader, the posted materials are not copyedited and are the sole responsibility of the authors, so questions or comments should be addressed to the corresponding author.Copyright © The Author(s) 2020. Background:
People with diabetes have an increased risk of developing active tuberculosis (TB) and are more likely to have poor TB-treatment outcomes, which may impact on control of TB as the prevalence of diabetes is increasing worldwide. Blood transcriptomes are altered in patients with active TB relative to healthy individuals. The effects of diabetes and intermediate hyperglycemia (IH) on this transcriptomic signature were investigated to enhance understanding of immunological susceptibility in diabetes-TB comorbidity.
Methods:
Whole blood samples were collected from active TB patients with diabetes (glycated hemoglobin [HbA1c] ≥6.5%) or IH (HbA1c = 5.7% to <6.5%), TB-only patients, and healthy controls in 4 countries: South Africa, Romania, Indonesia, and Peru. Differential blood gene expression was determined by RNA-seq (n = 249).
Results:
Diabetes increased the magnitude of gene expression change in the host transcriptome in TB, notably showing an increase in genes associated with innate inflammatory and decrease in adaptive immune responses. Strikingly, patients with IH and TB exhibited blood transcriptomes much more similar to patients with diabetes-TB than to patients with only TB. Both diabetes-TB and IH-TB patients had a decreased type I interferon response relative to TB-only patients.
Conclusions:
Comorbidity in individuals with both TB and diabetes is associated with altered transcriptomes, with an expected enhanced inflammation in the presence of both conditions, but also reduced type I interferon responses in comorbid patients, suggesting an unexpected uncoupling of the TB transcriptome phenotype. These immunological dysfunctions are also present in individuals with IH, showing that altered immunity to TB may also be present in this group. The TB disease outcomes in individuals with IH diagnosed with TB should be investigated further.European Union’s Seventh Framework Programme (FP7 2007-2013 - Health) under grant agreement No 305279