Beak deformation in an Antarctic Cormorant Phalacrocorax [atriceps] bransfieldensis chick

Fil: Casaux, Ricardo Jorge. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Universidad Nacional de la Patagonia; Argentin

Chern-Simons Supergravities with Off-Shell Local Superalgebras

A new family of supergravity theories in odd dimensions is presented. The Lagrangian densities are Chern-Simons forms for the connection of a supersymmetric extension of the anti-de Sitter algebra. The superalgebras are the supersymmetric extensions of the AdS algebra for each dimension, thus completing the analysis of van Holten and Van Proeyen, which was valid for N=1 and for D=2,3,4,mod 8. The Chern-Simons form of the Lagrangian ensures invariance under the gauge supergroup by construction and, in particular, under local supersymmetry. Thus, unlike standard supergravity, the local supersymmetry algebra closes off-shell and without requiring auxiliary fields. The Lagrangian is explicitly given for D=5, 7 and 11. In all cases the dynamical field content includes the vielbein, the spin connection, N gravitini, and some extra bosonic ``matter'' fields which vary from one dimension to another. The superalgebras fall into three families: osp(m|N) for D=2,3,4, mod 8, osp(N|m) for D=6,7,8, mod 8, and su(m-2,2|N) for D=5 mod 4, with m=2^{[D/2]}. The possible connection between the D=11 case and M-Theory is also discussed.Comment: 13pages, RevTeX, no figures, two column

Free Surface RANSE Analisys Around Fixed Fully Appended

This paper presents results of Free Surface RANSE (Reynolds Average Navier Stokes Equations) simulations of the flow around a MedCup TP52. Appendages forces calculations are important to know their hydrodynamic characteristics when they work jointly. In the ETSIN towing tank, some tests had begun to measure hydrodynamics forces in each appendage that allowed evaluate the forces distribution in different conditions. StarCCM+ has been used to compute drag, lift and wave elevation. It is shown how the CFD analysis has been prepared and the results obtained in these simulations comparing experimental with numerical results and the grid influence on it. Finally, it is observed that with limited resources, reasonable good results could be obtained

Canonical sectors of five-dimensional Chern-Simons theories

The dynamics of five-dimensional Chern-Simons theories is analyzed. These theories are characterized by intricate self couplings which give rise to dynamical features not present in standard theories. As a consequence, Dirac's canonical formalism cannot be directly applied due to the presence of degeneracies of the symplectic form and irregularities of the constraints on some surfaces of phase space, obscuring the dynamical content of these theories. Here we identify conditions that define sectors where the canonical formalism can be applied for a class of non-Abelian Chern-Simons theories, including supergravity. A family of solutions satisfying the canonical requirements is explicitly found. The splitting between first and second class constraints is performed around these backgrounds, allowing the construction of the charge algebra, including its central extension.Comment: 12 pages, no figure

Dynamical content of Chern-Simons Supergravity

The dynamical content of local AdS supergravity in five dimensions is discussed. The bosonic sector of the theory contains the vielbein ($e^{a}$), the spin connection ($\omega ^{ab}$) and internal SU(N) and U(1) gauge fields. The fermionic fields are complex Dirac spinors ($\psi ^{i}$) in a vector representation of SU(N). All fields together form a connection 1-form in the superalgebra SU(2,2|N). For N=4, the symplectic matrix has maximal rank in a locally AdS background in which the dynamical degrees of freedom can be identified. The resulting efective theory have different numbers of bosonic and fermionic degrees of freedom.Comment: 15pages, RevTeX, no figures, one column. Talk given at the Second Meeting on Trends in Theoretical Physics, Buenos Aires, November 30-December 4, 199

Higher dimensional Chern-Simons supergravity

A Chern-Simons action for supergravity in odd-dimensional spacetimes is proposed. For all odd dimensions, the local symmetry group is a non trivial supersymmetric extension of the Poincar\'e group. In $2+1$ dimensions the gauge group reduces to super-Poincar\'e, while for $D=5$ it is super-Poincar\'e with a central charge. In general, the extension is obtained by the addition of a 1-form field which transforms as an antisymmetric fifth-rank tensor under Lorentz rotations. Since the Lagrangian is a Chern-Simons density for the supergroup, the supersymmetry algebra closes off shell without the need of auxiliary fields.Comment: Revtex, 8 pages (two column format