Narrow-band photodetection based on M-plane GaN films

Rapid identification of a range of hazardous airborne biological and chemical agents requires simultaneous detection at several specific wavelengths, and consequently a set of photodetectors with very narrow-band spectral responsivity. We demonstrate two ultraviolet photodetection configurations based on strained M-plane GaN films on LiAlO2(100) substrates grown by molecular-beam epitaxy with a detection bandwidth below 8 nm. The optical band gap of the film depends on the orientation of the linear polarization of the incident light relative to the c-axis of GaN, which lies in the film plane. The first configuration consists of a polarizationsensitive planar Schottky photodetector and a filter. An orthogonal alignment of the c-axis of the photodetector and the filter produces a detection system with a peak responsivity at 360 nm and a bandwidth of 6 nm. The second one consists of two planar Schottky photodetectors with their c-axes oriented perpendicular to each other. The difference signal between the two photodetectors produces a peak responsivity at 358 nm and a bandwidth of 7.3 nm

Phase transitions in the spinless Falicov-Kimball model with correlated hopping

The canonical Monte-Carlo is used to study the phase transitions from the low-temperature ordered phase to the high-temperature disordered phase in the two-dimensional Falicov-Kimball model with correlated hopping. As the low-temperature ordered phase we consider the chessboard phase, the axial striped phase and the segregated phase. It is shown that all three phases persist also at finite temperatures (up to the critical temperature $\tau_c$) and that the phase transition at the critical point is of the first order for the chessboard and axial striped phase and of the second order for the segregated phase. In addition, it is found that the critical temperature is reduced with the increasing amplitude of correlated hopping $t'$ in the chessboard phase and it is strongly enhanced by $t'$ in the axial striped and segregated phase.Comment: 17 pages, 6 figure

Asymptotic Conformal Invariance in a Non-Abelian Chern-Simons-Matter Model

One shows here the existence of solutions to the Callan-Symanzik equation for the non-Abelian SU(2) Chern-Simons-matter model which exhibits asymptotic conformal invariance to every order in perturbative theory. The conformal symmetry in the classical domain is shown to hold by means of a local criteria based on the trace of the energy-momentum tensor. By using the recently exhibited regimes for the dependence between the several couplings in which the set of $\beta$-functions vanish, the asymptotic conformal invariance of the model appears to be valid in the quantum domain. By considering the SU(n) case the possible non validity of the proof for a particular n would be merely accidental.Comment: Latex2e 8 page

Central exclusive production of longlived gluinos at the LHC

We examine the possibility of producing gluino pairs at the LHC via the exclusive reaction pp -> p+gluino+gluino+p in the case where the gluinos are long lived. Such long lived gluinos are possible if the scalar super-partners have large enough masses. We show that it may be possible to observe the gluinos via their conversion to R-hadron jets and measure their mass to better than 1% accuracy for masses below 350 GeV with 300/fb of data.Comment: 13 pages, 9 figures. Minor corrections to version

The symmetry of the superconducting order parameter in PuCoGa5_5

The symmetry of the superconducting order parameter in single-crystalline PuCoGa$_5$ ($T_{\rm c} = 18.5$ K) is investigated via zero- and transverse- field muon spin relaxation ($\mu$SR) measurements, probing the possible existence of orbital and/or spin moments (time reversal-symmetry violation TRV) associated with the superconducting phase and the in-plane magnetic-field penetration depth $\lambda(T)$ in the mixed state, respectively. We find no evidence for TRV, and show that the superfluid density, or alternatively, $\Delta\lambda(T) = \lambda(T) - \lambda(0)$, are $\propto T$ for $T/T_{\rm c} \leq 0.5$. Taken together these measurements are consistent with an even-parity (pseudo-spin singlet), d-wave pairing state.Comment: 4 pages, 5 figure

t→bWt \to b W in NonCommutative Standard Model

We study the top quark decay to b quark and W boson in the NonCommutative Standard Model (NCSM). The lowest contribution to the decay comes from the terms quadratic in the matrix describing the noncommutative (NC) effects while the linear term is seen to identically vanish because of symmetry. The NC effects are found to be significant only for low values of the NC characteristic scale.Comment: 11 page Latex file containing 2 eps figures (redrawn). More discussion included. To appear in PR

A dual point description of mesoscopic superconductors

We present an analysis of the magnetic response of a mesoscopic superconductor, i.e. a system of sizes comparable to the coherence length and to the London penetration depth. Our approach is based on special properties of the two dimensional Ginzburg-Landau equations, satisfied at the dual point $(\kappa = \frac{1}{\sqrt{2}}).$ Closed expressions for the free energy and the magnetization of the superconductor are derived. A perturbative analysis in the vicinity of the dual point allows us to take into account vortex interactions, using a new scaling result for the free energy. In order to characterize the vortex/current interactions, we study vortex configurations that are out of thermodynamical equilibrium. Our predictions agree with the results of recent experiments performed on mesoscopic aluminium disks.Comment: revtex, 20 pages, 9 figure

Transcriptomics and proteomics reveal a cooperation between interferon and T-helper 17 cells in neuromyelitis optica

Type I interferon (IFN-I) and T helper 17 (TH17) drive pathology in neuromyelitis optica spectrum disorder (NMOSD) and in TH17-induced experimental autoimmune encephalomyelitis (TH17-EAE). This is paradoxical because the prevalent theory is that IFN-I inhibits TH17 function. Here we report that a cascade involving IFN-I, IL-6 and B cells promotes TH17-mediated neuro-autoimmunity. In NMOSD, elevated IFN-I signatures, IL-6 and IL-17 are associated with severe disability. Furthermore, IL-6 and IL-17 levels are lower in patients on anti-CD20 therapy. In mice, IFN-I elevates IL-6 and exacerbates TH17-EAE. Strikingly, IL-6 blockade attenuates disease only in mice treated with IFN-I. By contrast, B-cell-deficiency attenuates TH17-EAE in the presence or absence of IFN-I treatment. Finally, IFN-I stimulates B cells to produce IL-6 to drive pathogenic TH17 differentiation in vitro. Our data thus provide an explanation for the paradox surrounding IFN-I and TH17 in neuro-autoimmunity, and may have utility in predicting therapeutic response in NMOSD

Intragenic haplotypes at the bovine CSN1S1 locus

A new alternative genotyping method based on PCR-SSCP was developed for direct differentiation of the CSN1S1 alleles B and C in the coding region. In addition a PCR-RFLP test based on a MaeIII restriction site in the promoter region of CSN1S1, reported in the literature as an alternative test for the differentiation of CSN1S1*B and C was used and the alleles named b and c. Genotyping of 649 animals belonging to 17 European and Turkish cattle breeds showed differences in occurrence and frequency of the alleles. CSN1S1*B occurred in all breeds with frequencies varying from 0.50 in Anatolian Blackup to 1.0 in e.g. Ayrshire. CSN1S1*b on the other hand varied from 0.63 in Jersey, 0.97 in Ayrshire to 1.0 in e.g. Angler. Comparison of the results from both typing methods and positions in the gene showed that both mutations do not always occur together. From the resulting four intragenic haplotypes (B-b, B-c, C-c and C-b) B-b is predominant in all breeds with frequencies varying from 0.3450 in Anatolian Black to 1.0 in Angler and Scottish Highland. The number of haplotypes varied from only one in Angler and Scottish Highland, two in Ayrshire, three in Asturian Valley and Turkish Grey Steppe to all four in the other 12 breeds. Correlation between allele frequencies and the geographic origin of the breeds was significant for the MaeIII promoter polymorphism.O. Jann, E.-M. Prinzenberg, H. Brandt, J. L. Williams, P. Ajmone-Marsan, P. Zaragoza, C. Özbeyaz, and G. Erhard

Flux-lattice melting in two-dimensional disordered superconductors

The flux line lattice melting transition in two-dimensional pure and disordered superconductors is studied by a Monte Carlo simulation using the lowest Landau level approximation and quasi-periodic boundary condition on a plane. The position of the melting line was determined from the diffraction pattern of the superconducting order parameter. In the clean case we confirmed the results from earlier studies which show the existence of a quasi-long range ordered vortex lattice at low temperatures. Adding frozen disorder to the system the melting transition line is shifted to slightly lower fields. The correlations of the order parameter for translational long range order of the vortex positions seem to decay slightly faster than a power law (in agreement with the theory of Carpentier and Le Doussal) although a simple power law decay cannot be excluded. The corresponding positional glass correlation function decays as a power law establishing the existence of a quasi-long range ordered positional glass formed by the vortices. The correlation function characterizing a phase coherent vortex glass decays however exponentially ruling out the possible existence of a phase coherent vortex glass phase.Comment: 12 pages, 21 figures, final version to appear in Phys. Rev.