3,074 research outputs found
Skyrmion Generation by Current
Skyrmions, once a hypothesized field-theoretical object believed to describe
the nature of elementary particles, became common sightings in recent years
among several non-centrosymmetric metallic ferromagnets. For more practical
applications of Skyrmionic matter as carriers of information, thus realizing
the prospect of "Skyrmionics", it is necessary to have the means to create and
manipulate Skyrmions individually. We show through extensive simulation of the
Landau-Lifshitz-Gilbert equation that a circulating current imparted to the
metallic chiral ferromagnetic system can create isolated Skyrmionic spin
texture without the aid of external magnetic field.Comment: 8 pages, 5 figures, submitted to PR
Gauge symmetry enhancement in Hamiltonian formalism
We study the Hamiltonian structure of the gauge symmetry enhancement in the
enlarged CP(N) model coupled with U(2) Chern-Simons term, which contains a free
parameter governing explicit symmetry breaking and symmetry enhancement. After
giving a general discussion of the geometry of constrained phase space suitable
for the symmetry enhancement, we explicitly perform the Dirac analysis of our
model and compute the Dirac brackets for the symmetry enhanced and broken
cases. We also discuss some related issues.Comment: 8 pages, typos correcte
17β-Estradiol dysregulates innate immune responses to Pseudomonas aeruginosa respiratory infection and is modulated by estrogen receptor antagonism
ABSTRACT
Females have a more severe clinical course than males in terms of several inflammatory lung conditions. Notably, females with cystic fibrosis (CF) suffer worse outcomes, particularly in the setting of
Pseudomonas aeruginosa
infection. Sex hormones have been implicated in experimental and clinical studies; however, immune mechanisms responsible for this sex-based disparity are unknown and the specific sex hormone target for therapeutic manipulation has not been identified. The objective of this study was to assess mechanisms behind the impact of female sex hormones on host immune responses to
P. aeruginosa
. We used wild-type and CF mice, which we hormone manipulated, inoculated with
P. aeruginosa
, and then examined for outcomes and inflammatory responses. Neutrophils isolated from mice and human subjects were tested for responses to
P. aeruginosa
. We found that female mice inoculated with
P. aeruginosa
died earlier and showed slower bacterial clearance than males (
P
< 0.0001). Ovariectomized females supplemented with 17β-estradiol succumbed to
P. aeruginosa
challenge earlier than progesterone- or vehicle-supplemented mice (
P
= 0.0003). 17β-Estradiol-treated ovariectomized female mice demonstrated increased lung levels of inflammatory cytokines, and when rendered neutropenic the mortality difference was abrogated. Neutrophils treated with 17β-estradiol demonstrated an enhanced oxidative burst but decreased
P. aeruginosa
killing and earlier cell necrosis. The estrogen receptor (ER) antagonist ICI 182,780 improved survival in female mice infected with
P. aeruginosa
and restored neutrophil function. We concluded that ER antagonism rescues estrogen-mediated neutrophil dysfunction and improves survival in response to
P. aeruginosa
. ER-mediated processes may explain the sex-based mortality gap in CF and other inflammatory lung illnesses, and the ER blockade represents a rational therapeutic strategy.
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Anisotropic Dirac electronic structures of AMnBi2 (A = Sr, Ca)
Low-energy electronic structures in AMnBi(2) (A=alkaline earths) are investigated using a first-principles calculation and a tight binding method. An anisotropic Dirac dispersion is induced by the checkerboard arrangement of A atoms above and below the Bi square net in AMnBi(2 center dot) SrMnBi2 and CaMnBi2 have a different kind of Dirac dispersion due to the different stacking of nearby A layers, where each Sr (Ca) of one side appears at the coincident (staggered) xy position of the same element at the other side. Using the tight binding analysis, we reveal the chirality of the anisotropic Dirac electrons as well as the sizable spin-orbit coupling effect in the Bi square net. We suggest that the Bi square net provides a platform for the interplay between anisotropic Dirac electrons and the neighboring environment such as magnetism and structural changes.open6
Asexuality: Classification and characterization
This is a post-print version of the article. The official published version can be obtaineed at the link below.The term “asexual” has been defined in many different ways and asexuality has received very little research attention. In a small qualitative study (N = 4), individuals who self-identified as asexual were interviewed to help formulate hypotheses for a larger study. The second larger study was an online survey drawn from a convenience sample designed to better characterize asexuality and to test predictors of asexual identity. A convenience sample of 1,146 individuals (N = 41 self-identified asexual) completed online questionnaires assessing sexual history, sexual inhibition and excitation, sexual desire, and an open-response questionnaire concerning asexual identity. Asexuals reported significantly less desire for sex with a partner, lower sexual arousability, and lower sexual excitation but did not differ consistently from non-asexuals in their sexual inhibition scores or their desire to masturbate. Content analyses supported the idea that low sexual desire is the primary feature predicting asexual identity
A complete solution of a Constrained System: SUSY Monopole Quantum Mechanics
We solve the quantum mechanical problem of a charged particle on S^2 in the
background of a magnetic monopole for both bosonic and supersymmetric cases by
constructing Hilbert space and realizing the fundamental operators obeying
complicated Dirac bracket relations in terms of differential operators. We find
the complete energy eigenfunctions. Using the lowest energy eigenstates we
count the number of degeneracies and examine the supersymmetric structure of
the ground states in detail.Comment: 20 pages including the title, prepared in JHEP forma
Maxwell Chern-Simons Solitons from Type IIB String Theory
We study various three-dimensional supersymmetric Maxwell Chern-Simons
solitons by using type IIB brane configurations. We give a systematic
classification of soliton spectra such as topological BPS vortices and
nontopological vortices in supersymmetric Maxwell
Chern-Simons system via the branes of type IIB string theory. We identify the
brane configurations with the soliton spectra of the field theory and obtain a
nice agreement with field theory aspects. We also discuss possible brane
constructions for BPS domain wall solutions.Comment: 23 pages, Latex, 4 figures; (q_1,q_2)-string convention changed,
minor correction
Couplings of the Rho Meson in a Holographic dual of QCD with Regge Trajectories
The couplings of the meson with any hadron H are
calculated in a holographic dual of QCD where the Regge trajectories for mesons
are manifest. The resulting couplings grow linearly with the exciting number of
H, thus are far from universal. A simple argument has been given for this
behavior based on quasi-classical picture of excited hadrons. It seems that in
holographic duals with exact Regge trajectories the universality
should be violated. The -dominance for the electromagnetic form factors
of H are also strongly violated, except for the lowest state, the pion. Quite
unexpected, the form factor of the pion is completely saturated by the
contribution of the . The asymptotic behavior of the form factors are
also calculated, and are found to be perfectly accordant with the prediction of
conformal symmetry and pertubative QCD.Comment: 9 page
Fluctuations around the Tachyon Vacuum in Open String Field Theory
We consider quadratic fluctuations around the tachyon vacuum numerically in
open string field theory. We work on a space spanned
by basis string states used in the Schnabl's vacuum solution. We show that the
truncated form of the Schnabl's vacuum solution on is
well-behaved in numerical work. The orthogonal basis for the new BRST operator
on and the quadratic forms of potentials
for independent fields around the vacuum are obtained. Our numerical results
support that the Schnabl's vacuum solution represents the minimum energy
solution for arbitrary fluctuations also in open string field theory.Comment: 16 pages, 2 figures, some comments and one table added, version to
appear in JHE
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