Kalb-Ramond excitations in a thick-brane scenario with dilaton

We compute the full spectrum and eigenstates of the Kalb-Ramond field in a warped non-compact Randall-Sundrum -type five-dimensional spacetime in which the ordinary four-dimensional braneworld is represented by a sine-Gordon soliton. This 3-brane solution is fully consistent with both the warped gravitational field and bulk dilaton configurations. In such a background we embed a bulk antisymmetric tensor field and obtain, after reduction, an infinite tower of normalizable Kaluza-Klein massive components along with a zero-mode. The low lying mass eigenstates of the Kalb-Ramond field may be related to the axion pseudoscalar. This yields phenomenological implications on the space of parameters, particularly on the dilaton coupling constant. Both analytical and numerical results are given.Comment: 10 pages, 13 figures, and 2 tables. Final version to appear in The European Physical Journal

Renormalization of the commutative scalar theory with harmonic term to all orders

The noncommutative scalar theory with harmonic term (on the Moyal space) has a vanishing beta function. In this paper, we prove the renormalizability of the commutative scalar field theory with harmonic term to all orders by using multiscale analysis in the momentum space. Then, we consider and compute its one-loop beta function, as well as the one on the degenerate Moyal space. We can finally compare both to the vanishing beta function of the theory with harmonic term on the Moyal space.Comment: 16 page

Inter-annual variability on the influence of equatorial upwelling on biological productivity along 10oW in the Eastern Equatorial Atlantic (EEA)

Of the 3 boreal summers covered by the EGEE oceanographic cruises between 2005 and 2007, equatorial upwelling was strongest along 10oW in June 2005 and weakest in June 2006. In response to the shoaling pycnocline, cold nutrient-rich waters upwelled to the euphotic layer and significantly influenced the biological productivity of the region in June 2005. Using profiles for temperature, salinity and dissolved oxygen (at the latitude of Equatorial Under-Current (EUC) velocity core) and chlorophyll fluorescence profile (at the latitude of maximum occurrences within the EUC latitude bands), the hypothesis of the EUC contributing to the equatorial fertility process along 10oW was captured. While nitrate was limiting to phytoplankton growth in June 2006 and June 2007, phosphate stress was observed in June 2005

On the nutrient distribution and phytoplankton biomass in the Gulf of Guinea equatorial band as inferred from in-situ measurements

Oceanographic in situ data collected in the Gulf of Guinea during six cruises carried out between 2005 and 2007 were analysed to study the influence of equatorial upwelling on the productivity of the region. At 10°W, observations during boreal summer and autumn cruises captured seasonal upwelling influences. In response to the shoaling pycnocline in June 2005, higher concentrations of nitrate and chlorophyll fluorescence were recorded at the ocean surface in June than in September. Our findings challenge the paradigm that westward advection from the nutrient-rich African coast is responsible for equatorial enrichment in the Gulf of Guinea. Vertical sections of the parameters under study in the summer of 2005 showed no westward advection from 3°E to 10°W within the equatorial band. This emphasizes the important role of vertical processes in equatorial enrichment at 10°W. An additional aspect of our study provides evidence of the impact on nutrient and chlorophyll distribution of offequatorial westward recirculation of equatorial undercurrent waters (observed between 2°and 3°S)

Classes of f-Deformed Landau Operators: Nonlinear Noncommutative Coordinates from Algebraic Representations

We consider, in a superspace, new operator dependent noncommutative (NC) geometries of the nonlinear quantum Hall limit related to classes of f-deformed Landau operators in the spherical harmonic well. Different NC coordinate algebras are determined using unitary representation spaces of Fock-Heisenberg tensored algebras and of the Schwinger-Fock realisation of the su(1,1) Lie algebra. A reduced model allowing an underlying N=2 superalgebra is also discussed. Comment: Contribution to the Proceedings of the Fifth International Workshop on Contemporary Problems in Mathematical Physics, October 27 - November 2, 2007, Cotonou (Republic of Benin), 6 page