4,807 research outputs found
Resonant Leptogenesis with nonholomorphic R-Parity violation and LHC Phenomenology
In R-parity violating supersymmetric models both leptogenesis and the correct
neutrino masses are hard to achieve together. The presence of certain soft
nonholomorphic R-parity violating terms helps to resolve this problem. We
consider a scenario where the lightest and the second-lightest neutralino are
nearly degenerate in mass and enough CP-asymmetry can be produced through
resonant leptogenesis. In this model, the lighter chargino and the lightest
neutralino are highly degenerate. We have relatively lighter gauginos which can
be produced at the LHC leading to heavily ionizing charged tracks. At the same
time this model can also generate the correct neutrino mass scale. Thus our
scenario is phenomenologically rich and testable at colliders.Comment: 17 pages, 7 figures, Numerical results are improved and new plots are
added, Journal version. arXiv admin note: text overlap with
arXiv:hep-ph/0006173 by other author
Keypad mobile phones are associated with a significant increased risk of microbial contamination compared to touch screen phones
The use of mobile phones in the clinical environment by healthcare workers has become widespread. Despite evidence that these devices can harbour pathogenic micro-organisms there is little guidance on how to reduce contamination. Recently touchscreen phones with a single flat surface have been introduced. We hypothesise that bacterial contamination of phones used in hospitals will be lower on touchscreen devices compared to keypad devices. Sixty seven mobile phones belonging to health care workers were sampled. The median colony count for touchscreen phones and keypad devices was 0·09 colony forming units (cfu)/cm2 (interquartile range (IQR) 0.05–0·14) and 0·77 cfu/cm2 (IQR range 0·45–3.52) respectively. Colony counts were significantly higher on the keypad phones (Fisher’s exact test p<0.001). Multivariate analysis showed the type of phone (keypad vs. touch screen) was associated with increased colony counts (F-statistic 14.13: p<0.001). Overall, nine (13%) phones grew either meticillin resistant Staphylococcus aureus or vancomycin resistant enterococci. Eight (24%) keypad phones were contaminated with these organisms compared with one touch screen phone (3%). Our data indicate that touchscreen mobile phones are less contaminated than their keypad counterparts, and they are less likely to harbour pathogenic bacteria in the clinical setting
LRH-1 mitigates intestinal inflammatory disease by maintaining epithelial homeostasis and cell survival.
Epithelial dysfunction and crypt destruction are defining features of inflammatory bowel disease (IBD). However, current IBD therapies targeting epithelial dysfunction are lacking. The nuclear receptor LRH-1 (NR5A2) is expressed in intestinal epithelium and thought to contribute to epithelial renewal. Here we show that LRH-1 maintains intestinal epithelial health and protects against inflammatory damage. Knocking out LRH-1 in murine intestinal organoids reduces Notch signaling, increases crypt cell death, distorts the cellular composition of the epithelium, and weakens the epithelial barrier. Human LRH-1 (hLRH-1) rescues epithelial integrity and when overexpressed, mitigates inflammatory damage in murine and human intestinal organoids, including those derived from IBD patients. Finally, hLRH-1 greatly reduces disease severity in T-cell-mediated murine colitis. Together with the failure of a ligand-incompetent hLRH-1 mutant to protect against TNFα-damage, these findings provide compelling evidence that hLRH-1 mediates epithelial homeostasis and is an attractive target for intestinal disease
A Mixed Integer Efficient Global Optimization Algorithm for the Simultaneous Aircraft Allocation-Mission-Design Problem
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143026/1/6.2017-1305.pd
Non-integer flux quanta for a spherical superconductor
A thin film superconductor shaped into a spherical shell at whose center lies
the end of long thin solenoid in which there is an integer flux has
been previously extensively studied numerically as a model of a two-dimensional
superconductor. The emergent flux from the solenoid produces a radial B-field
at the superconducting shell and vortices in the superconducting film. We
study here the effects of including a second solenoid (carrying a flux )
which is inserted inside the first solenoid but passing right across the
sphere. This Aharonov-Bohm (AB) flux does not have to be quantized to make the
order parameter single valued. The Ginzburg-Landau (GL) free energy is
minimized at fixed as a function of and it is found that the minimum is
usually achieved when the AB flux is half a flux quantum, but depending on
the minimum may be at or values which are not obvious rational
fractions.Comment: 6 pages, RevTeX, 5 figures include
Fractional Quantum Hall Effect via Holography: Chern-Simons, Edge States, and Hierarchy
We present three holographic constructions of fractional quantum Hall effect
(FQHE) via string theory. The first model studies edge states in FQHE using
supersymmetric domain walls in N=6 Chern-Simons theory. We show that D4-branes
wrapped on CP^1 or D8-branes wrapped on CP^3 create edge states that shift the
rank or the level of the gauge group, respectively. These holographic edge
states correctly reproduce the Hall conductivity. The second model presents a
holographic dual to the pure U(N)_k (Yang-Mills-)Chern-Simons theory based on a
D3-D7 system. Its holography is equivalent to the level-rank duality, which
enables us to compute the Hall conductivity and the topological entanglement
entropy. The third model introduces the first string theory embedding of
hierarchical FQHEs, using IIA string on C^2/Z_n.Comment: 36 pages, 6 figures; v2: with an improved derivation of Hall
conductivity in section 3.2, typo corrections, and additional references; v3:
explanations and comments adde
Spectrum of the Vortex Bound States of the Dirac and Schrodinger Hamiltonian in the presence of Superconducting Gaps
We investigate the vortex bound states both Schrodinger and Dirac Hamiltonian
with the s-wave superconducting pairing gap by solving the mean-field
Bogoliubov-de-Gennes equations. The exact vortex bound states spectrum is
numerically determined by the integration method, and also accompanied by the
quasi-classical analysis. It is found that the bound state energies is
proportional to the vortex angular momentum when the chemical potential is
large enough. By applying the external magnetic field, the vortex bound state
energies of the Dirac Hamiltonian are almost unchanged; whereas the energy
shift of the Schrodinger Hamiltonian is proportional to the magnetic field.
These qualitative differences may serve as an indirect evidence of the
existence of Majorana fermions in which the zero mode exists in the case of the
Dirac Hamiltonian only.Comment: 8 pages, 9 figure
Photons from Jet - Plasma Interaction in collisional energy loss scenario
We calculate photons from jet plasma interaction in a collisional energy loss
scenario. It is shown that the PHENIX photon data is well reproduced when
photons from initial hard collisions are taken into account.Comment: 4 pages, 2 figures, the poster presentation prepared for Quark Matter
2008: 20th International Conference on Ultra - Relativistic Nucleus Nucleus
collisions (QM 2008), Jaipur, India, 4-10th Feb 200
Large, high quality single-crystals of the new Topological Kondo Insulator, SmB6
SmB6 has recently been predicted to be a Topological Kondo Insulator, the first strongly correlated heavy fermion material to exhibit topological surface states. High quality crystals are necessary to investigate the topological properties of this material. Single crystal growth of the rare earth hexaboride, SmB6, has been carried out by the floating zone technique using a high power xenon arc lamp image furnace. Large, high quality single-crystals are obtained by this technique. The crystals produced by the floating zone technique are free of contamination from flux materials and have been characterised by resistivity and magnetisation measurements. These crystals are ideally suited for the investigation of both the surface and bulk properties of SmB6
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