BTZ Black Hole Entropy from a Chern-Simons Matrix Model

We examine a Chern-Simons matrix model which we propose as a toy model for studying the quantum nature of black holes in 2+1 gravity. Its dynamics is described by two $N\times N$ matrices, representing the two spatial coordinates. The model possesses an internal SU(N) gauge symmetry, as well as an external rotation symmetry. The latter corresponds to the rotational isometry of the BTZ solution, and does not decouple from SU(N) gauge transformations. The system contains an invariant which is quadratic in the spatial coordinates. We obtain its spectrum and degeneracy, and find that the degeneracy grows exponentially in the large $N$ limit. The usual BTZ black hole entropy formula is recovered upon identifying the quadratic invariant with the square of the black hole horizon radius. The quantum system behaves collectively as an integer (half-integer) spin particle for even (odd) $N$ under $2\pi$-rotations.Comment: 17 page

Nomenclatural changes for selected Mordellidae (Coleoptera) in North America

New nomenclatural changes are presented for selected North American mordellid beetles (Coleoptera: Mordellidae). The following five genera are newly recorded fi.·om the United States: Mordellaria Ermisch 1950, Falsomordellistena Ermisch 1941, Mordellina Schilsky 1908, Mordellochroa Emery 1876, and Pseudotolida Ermisch 1950. The following species are transferred from Tomoxia and represent new combinations: Mordellaria borealis (LeConte 1862), Mordellaria fascifera (LeConte 1878), Mordellaria latipalpis (Ray 1946), Mordellaria serval (Say 1835), and Mordellaria undulata (Melsheimer 1845). The following species are transferred fi.·om Mordellistena and represent new combinations: Falsomordellistena hebraica (LeConte 1862) and Falsomordellistena pubescens (Fabricius 1798); Mordellina blatchleyi (Liljeblad 1945), Mordellina pilosella (Ray 1947), Mordellina pustulata (Melsheimer 1845), Mordellina ustulata (LeConte 1862), and Mordellina wichhami (Liljeblad 1945); Mordellochroa scapularis (Say 1824); Pseudotolida arida (LeConte 1862), Pseudotolida hnausi (Liljeblad 1945), and Pseudotolida lutea (Melsheimer 1845). Mordellina ustulata (LeConte 1862) represents a return to species rank after being treated as a subspecies of Mordellistena andreae LeConte 1862. There are a total of 17 genera of Mordellidae in America north of Mexico

Synergistic Effect of Carbon Nanotubes and Decabromodiphenyl Oxide/Sb\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e in Improving the Flame Retardancy of Polystyrene

Brominated flame retardant polystyrene composites were prepared by melt blending polystyrene, decabromodiphenyl oxide, antimony oxide, multi-wall carbon nanotubes and montmorillonite clay. Synergy between carbon nanotubes and clay and the brominated fire retardant was studied by thermogravimetric analysis, microscale combustion calorimetry and cone calorimetry. Nanotubes are more efficient than clay in improving the flame retardancy of the materials and promoting carbonization in the polystyrene matrix. Comparison of the results from the microscale combustion calorimeter and the cone calorimeter indicate that the rate of change of the peak heat release rate reduction in the microscale combustion calorimeter was slower than that in the cone. Both heat release capacity and reduction in the peak heat release rate in the microscale combustion calorimeter are important for screening the flame retardant materials; they show good correlations with the cone parameters, peak heat release rate and total heat released

Scaling of Yukawa Couplings and Quark Flavor Mixings in the UED Model

The evolution properties of Yukawa couplings and quark mixings are performed for the one-loop renormalization group equations in the Universal Extra Dimension (UED) model. It is found that the UED model has a substantial effect on the scaling of the fermion masses, including both quark and lepton sectors, whilst the radiative effects on the unitarity triangle is not a sensitive test in this model. Also, for this model, the renormalization invariants $R_{13}$ and $R_{23}$ describe the correlation between the mixing angles and mass ratios to a good approximation, with a variation of the order of $\lambda^4$ and $\lambda^5$ under energy scaling respectively.Comment: 5 pages, 10 figures, Talk presented at the Workshop on Discovery Physics at the LHC -Kruger 2010, December 05-10, 2010. To appear in the PoS workshop proceeding

A process yields large quantities of pure ribosome subunits

Development of process for in-vitro protein synthesis from living cells followed by dissociation of ribosomes into subunits is discussed. Process depends on dialysis or use of chelating agents. Operation of process and advantages over previous methods are outlined

Coupled thermo-mechanical damage modelling for structural steel in fire conditions

This paper aims at developing a coupled thermo-mechanical damage model for structural 6 steel at elevated temperatures. The need for adequate modelling of steel deterioration behaviour 7 remains a challenging task in structural fire engineering because of the complexity inherent in 8 the damage states of steel under combined actions of mechanical and fire loading. A fully three9 dimensional damage-coupled constitutive model is developed in this work based on the hypothesis 10 of effective stress space and isotropic damage theory. The new coupling model, adapted from 11 an enhanced Lemaitre’s ductile damage equation and taking into account temperature-dependent 12 thermal degradation, is a phenomenological approach where the underlying mechanisms that govern 13 the damage processes have been retained. The proposed damage model comprises a limited number 14 of parameters that could be identified using unloading slopes of stress-strain relationships through 15 tensile coupon tests. The proposed damage model is successfully implemented in the finite element 16 software ABAQUS and validated against a comprehensive range of experimental results. The 17 damage-affected structural response is accurately reproduced under various loading conditions and 18 a wide temperature range, demonstrating that the proposed damage model is a useful tool in giving a 19 realistic representation of steel deterioration behaviour for structural fire engineering applications

Effects of the third-order dispersion on continuous waves in complex potentials

A class of constant-amplitude (CA) solutions of the nonlinear Schrodinger equation with the third-order spatial dispersion (TOD) and complex potentials are considered. The system can be implemented in specially designed planar nonlinear optical waveguides carrying a distribution of local gain and loss elements, in a combination with a photonic-crystal structure. The complex potential is built as a solution of the inverse problem, which predicts the potential supporting a required phase-gradient structure of the CA state. It is shown that the diffraction of truncated CA states with a correct phase structure can be strongly suppressed. The main subject of the analysis is the modulational instability (MI) of the CA states. The results show that the TOD term tends to attenuate the MI. In particular, simulations demonstrate a phenomenon of weak stability, which occurs when the linear-stability analysis predicts small values of the MI growth rate. The stability of the zero state, which is a nontrivial issue in the framework of the present model, is studied tooComment: 8 pages, 8 figures, Eur. Phys. J. D, in pres