1,942 research outputs found
Light axigluon and single top production at the LHC
The light axigluon model can explain the Tevatron
forward-backward asymmetry and at the same time satisfy the constraints from
the electroweak precision measurement and the and data, which
induces the flavor changing () couplings of axigluon with the and new
quarks. We investigate the effects of these couplings on the s- and
t-channel single top productions at the and the decays , and . Our numerical
results show that the light axigluon can give significantly contributions to
single top production and the rare top decays and .Comment: 22 pages, 8 figures; references added, contributions of new quarks to
rare decay processes adde
Bottom partner B' and Zb production at the LHC
Some new physics models, such as "beautiful mirrors" scenario, predict the
existence of the bottom partner . Considering the constraints from the data
for the branching ratio and the asymmetry
on the relevant free parameters, we calculate the contributions of
to the cross section and the polarization asymmetry
for production at the . We find that the bottom partner
can generate significant corrections to and , which might
be detected in near future.Comment: 15 pages, 5 figures. Version published in Phys. Lett.
Universal scheme to generate metal-insulator transition in disordered systems
We propose a scheme to generate metal-insulator transition in random binary
layer (RBL) model, which is constructed by randomly assigning two types of
layers. Based on a tight-binding Hamiltonian, the localization length is
calculated for a variety of RBLs with different cross section geometries by
using the transfer-matrix method. Both analytical and numerical results show
that a band of extended states could appear in the RBLs and the systems behave
as metals by properly tuning the model parameters, due to the existence of a
completely ordered subband, leading to a metal-insulator transition in
parameter space. Furthermore, the extended states are irrespective of the
diagonal and off-diagonal disorder strengths. Our results can be generalized to
two- and three-dimensional disordered systems with arbitrary layer structures,
and may be realized in Bose-Einstein condensates.Comment: 5 ages, 4 figure
Remote information concentration and multipartite entanglement in multilevel systems
Remote information concentration (RIC) in -level systems (qudits) is
studied. It is shown that the quantum information initially distributed in
three spatially separated qudits can be remotely and deterministically
concentrated to a single qudit via an entangled channel without performing any
global operations. The entangled channel can be different types of genuine
multipartite pure entangled states which are inequivalent under local
operations and classical communication. The entangled channel can also be a
mixed entangled state, even a bound entangled state which has a similar form to
the Smolin state, but has different features from the Smolin state. A common
feature of all these pure and mixed entangled states is found, i.e., they have
common commuting stabilizers. The differences of qudit-RIC and qubit-RIC
() are also analyzed.Comment: 10 pages, 3 figure
Expression of hypoxia inducible factor-1α and vascular endothelial growth factor-C in human chronic periodontitis
AbstractBackground/purposeEvidence shows that there is a relationship between hypoxia and inflammatory response in periodontitis. Hypoxia-inducible factor (HIF)-1α is a major regulator of energy homeostasis and cellular adaptation to low oxygen stress. Although experimental results demonstrate an association between HIF-1α and vascular endothelial growth factor (VEGF)-C in tumor angiogenesis, the role of HIF-1α and VEGF-C in the pathogenesis of periodontitis is still ambiguous. So far, limited attention has been given to the role of hypoxia and VEGF-C in periodontitis. The present study aimed to investigate the expression and distribution of HIF-1α and VEGF-C in gingival tissue samples from patients with different stages of chronic periodontitis and healthy individuals.Materials and methodsA total of 56 samples were involved in this study, including moderate chronic periodontitis (n = 20), advanced chronic periodontitis (n = 20), and healthy control tissues (n = 16). The gingival specimens were stained with hematoxylin and eosin for histopathology. The expression of HIF-1α and VEGF-C in gingival tissues was detected by immunohistochemical staining.ResultsHIF-1α and VEGF-C were found in gingival tissues from patients with different stages of chronic periodontitis as well as healthy control tissues. HIF-1α protein was expressed mainly in the epithelial layer of gingival tissues, and VEGF-C protein was mostly located in the connective tissue papilla of gingival tissues. Compared with healthy controls, the expression of HIF-1α and VEGF-C in chronic periodontitis groups was significantly higher (P < 0.01), and the density of HIF-1α and VEGF-C in advanced chronic periodontitis group was even significantly higher than that in the moderate chronic periodontitis group (P < 0.01).ConclusionOur results suggest that the expression of HIF-1α and VEGF-C increased with severity of periodontitis. So, we conclude that HIF-1α may play an important role in the pathophysiology of human periodontitis and may be related to the function of VEGF-C during periodontitis
ON THE EXISTENCE AND UNIQUENESS OF A LIMIT CYCLE FOR A LIENARD SYSTEM WITH A DISCONTINUITY LINE
In this paper, we investigate the existence and uniqueness of crossing limit cycle for a planar nonlinear Lienard system which is discontinuous along a straight line (called a discontinuity line). By using the Poincare mapping method and some analysis techniques, a criterion for the existence, uniqueness and stability of a crossing limit cycle in the discontinuous differential system is established. An application to Schnakenberg model of an autocatalytic chemical reaction is given to illustrate the effectiveness of our result. We also consider a class of discontinuous piecewise linear differential systems and give a necessary condition of the existence of crossing limit cycle, which can be used to prove the non-existence of crossing limit cycle
Hexa-μ2-acetato-κ12 O:O′-(azido-κN)bisÂ(methanol-κO)-μ3-oxido-trichromium(III) methanol monosolvate
In the crystal structure of the title complex, [Cr3(CH3CO2)6(N3)O(CH3OH)2]·CH3OH, the trinuclear core has a central O atom; two methanol molÂecules and an azide ion are coordinated to the CrIII atoms in the core. The three CrIII atoms form vertices of a nearly equilateral triangle. Each of the six acetate carboxylÂate groups bridges a Cr—O—Cr fragment. In the crystal, the molecules interÂact with methanol solvent molÂecules through O—H⋯O and O—H⋯N hydrogen bonds, forming a two-dimensional hydrogen-bonded network parallel to (100)
- …