Extended D = 3 Bargmann supergravity from a Lie algebra expansion

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New Supersymmetric Solutions in N=2 Matter Coupled AdS_3 Supergravities

We construct new 1/2 supersymmetric solutions in D=3, N=2, matter coupled, U(1) gauged supergravities and study some of their properties. We do this by employing a quite general supersymmetry breaking condition, from which we also redrive some of the already known solutions. Among the new solutions, we have an explicit non-topological soliton for the non-compact sigma model, a locally flat solution for the compact sigma model and a string-like solution for both types of sigma models. The last one is smooth for the compact scalar manifold.Comment: 1+21 pages, 2 figures, LaTeX2e, JHEP style; v2: added one reference + made minor changes and added a few comments to clarify the presentatio

Kink fluctuation asymptotics and zero modes

In this paper we propose a refinement of the heat kernel/zeta function treatment of kink quantum fluctuations in scalar field theory, further analyzing the existence and implications of a zero energy fluctuation mode. Improved understanding of the interplay between zero modes and the kink heat kernel expansion delivers asymptotic estimations of one-loop kink mass shifts with remarkably higher precision than previously obtained by means of the standard Gilkey-DeWitt heat kernel expansion.Comment: 21 pages, 8 figures, to be published in The European Physical Journal

Analizando el reconocimiento de grafos a través del modelo de Van Hiele

En este trabajo, estudiamos la evolución del proceso de reconocimiento en el campo de la Teoría de Grafos desde la perspectiva del modelo de van Hiele. Así como Gutiérrez y Jaime (1998) plantean dos niveles para este proceso en el área de Geometría (primero visual, y después a través de propiedades), nosotros proponemos además un tercer nivel donde los estudiantes reconocen relaciones entre propiedades y las posibles traslaciones entre modos de representación de grafos. Además, otra diferencia importante con respecto al caso geométrico es que los estudiantes en el primer nivel pueden reconocer toda una serie de propiedades globales de los grafos, pues para figuras geométricas éstas son básicamente el número de vértices y de lados

Experimental validation of a rans-vof numerical model of the wave generation and propagation in a 2d wave flume

This paper focus on the study of free surface variation in a Numerical Wave Flume (NWF) due to a paddle movement. The NWF is the numerical representation of a 12.5 meters long Experimental Wave Flume (EWF) of the laboratory of the University of the Basque Country. The experiments and the numerical simulations are performed in several depths (0.3, 0.4 and 0.5 meters). Besides different velocities for the paddle movement are induced between 0.064 and 0.1 m/s. The numerical simulations are based on an Eulerian Multiphase of two fluids, air and water, more concretely the Volume of Fluid model. The surface variation in two points (6.0 and 6.3 meters from the wave flume start) is studied in both numerical and experimental wave flumes and compared its variation through the experiment time. Besides, the experiments will be analyzed in the wave maker theory. The results show the models quality in the first moments of the experiments, where the reflection does not appear, in which the results from both experimental and numerical simulations are pretty similar

M-Theory Giant Gravitons with C field

We find giant graviton configurations of an M5-brane probe in the D=11 supergravity background generated by a stack of non-threshold (M2,M5) bound states. The M5-brane probe shares three directions with the background and wraps a two-sphere transverse to the bound states. For a particular value of the worldvolume gauge field of the PST formalism, there exist solutions of the equations of motion for which the M5-brane probe behaves as a wave propagating in the (M2,M5) background. We have checked that the probe breaks the supersymmetry of the background exactly as a massless particle moving along the trajectory of its center of mass.Comment: 11 pages, LaTeX; v2: references adde

A comparative study of the electrochemical properties of vitamin B-6 related compounds at physiological pH

A comparative study of vitamin B6 group and related compounds in buffered solutions using electrochemical techniques has been performed at neutral pH. Irreversible bi- or tetra-electronic processes are observed for these substances, and the electron transfer coefficient (αn) calculated. It was concluded that either the first or second electron transfer were the rate determining step of the electrode process. The diffusion coefficient of these substances was calculated and the values given follow an inverse tendency to the molecular size. For aldehydes the values obtained were corrected of the hydration reaction. It is important to remark that catalytic waves were reported for the first time for these compounds. Using a model involving the nitrogen of the basic structure the kinetic constants were calculated for most of them

Dyonic Membranes

We present dyonic multi-membrane solutions of the N=2 D=8 supergravity theory that serves as the effective field theory of the $T^2$-compactified type II superstring theory. The `electric' charge is fractional for generic asymptotic values of an axion field, as for D=4 dyons. These membrane solutions are supersymmetric, saturate a Bogomolnyi bound, fill out orbits of an $Sl(2;\Z)$ subgroup of the type II D=8 T-duality group, and are non-singular when considered as solutions of $T^3$-compactified D=11 supergravity. On $K_3$ compactification to D=4, the conjectured type II/heterotic equivalence allows the $Sl(2;\Z)$ group to be reinterpreted as the S-duality group of the toroidally compactified heterotic string and the dyonic membranes wrapped around homology two-cycles of $K_3$ as S-duals of perturbative heterotic string states.Comment: Phyzzx. 27 pp. Additional para. added to introductio