Exclusive production of ω\omega meson in proton-proton collisions at high energies

First we calculate cross section for the $\gamma p \to \omega p$ reaction from the threshold to very large energies. At low energies the pion exchange is the dominant mechanism. At large energies the experimental cross section can be well described within the $k_{t}$-factorization approach by adjusting light-quark constituent mass. Next we calculate differential distributions for the $p p \to p p \omega$ reaction at RHIC, Tevatron and LHC energies for the first time in the literature. We consider photon-pomeron (pomeron-photon), photon-pion (pion-photon) as well as diffractive hadronic bremsstrahlung mechanisms. The latter are included in the meson/reggeon exchange picture with parameters fixed from the known phenomenology. Interesting rapidity distributions are predicted. The hadronic bremsstrahlung contributions dominate at large (forward, backward) rapidities. At small energies the photon-pomeron contribution is negligible compared to the bremsstrahlung contributions. It could be, however, easily identified at large energies at midrapidities. Absorptions effects are included and discussed. Our predictions are ready for verification at RHIC and LHC.Comment: 21 pages, 14 figure

Fronts and mesoscale variability in the southern Indian Ocean as inferred from the TOPEX/POSEIDON and ERS-2 altimetry data

Charts of sea level anomalies (SLA) based on the combined altimetry data from the TOPEX/POSEIDON and ERS-2 satellites, as well as the corresponding charts of the sea surface dynamic heights (constructed by the superposition of SLA distributions over the climatic dynamic topography) and the temperature gradients at the ocean surface on the basis of the satellite Multi-Channel Sea Surface Temperature (MCSST) data, were used to study the mesoscale variability related to the fronts in the Southern Indian Ocean (30degrees-60degrees S, 20degrees-150degrees E). An analysis of these three types of satellite information for the central weeks of each month during the period from 1997 to 1999 allowed us to distinguish zones of enhanced meandering (eddy formation) within the basin under study, as well as the contributions of individual fronts and their interaction to the regional mesoscale variability. The problems of the correlation between the intensity of mesoscale variability and peculiarities of the local bottom topography and seasonal/interannual variability of mesoscale dynamics are addressed.Belcant

Anticyclonic eddies in the deep eastern Black Sea in summer-autumn 1999 (satellite and ship-borne observations

peer reviewe

Fronts in the Southern Indian Ocean as inferred from satellite sea surface temperature data

Sea surface temperature (SST) derived from the weekly measurements made by the Advanced Very High Resolution Radiometers (AVHRR) of NOAA satellites was used to investigate the structure and space-time variability of large-scale fronts in the Southern Indian Ocean (30-60degreesS and 20-150degreesE) during the period of 1997-1999. Monthly SST gradient maps provided an overall view of five basic fronts: the North and South Subtropical fronts (NSTF and SSTF, respectively), the Agulhas Front (AF), the Subantarctic Front (SAF), and the Polar Front (PF). Mean location of the fronts and associated SST and SST gradients with corresponding standard deviations were calculated at each 10degrees-spaced longitude. A double structure of the NSTF, SAF, and PF was demonstrated as well as the meandering of all fronts with amplitudes of 2-5degrees in latitude and wavelength of several degrees in longitude. Convergence and transient interaction between neighboring fronts appear to occur not only in the Crozet and Kerguelen regions, but in other regions as well. The mean locations and SST range of every front are in good agreement with previous work based on hydrographic surveys [J. Geophys. Res. 101 (1996) 3675], although some details are different (in particular, the larger zonal extent of the NSTF and the wider frontal SST ranges than previously observed). A good correspondence of the measurements made during two hydrographic surveys in the Kerguelen region (22 January-3 February 1999) and in the Tasmania region (3-22 March 1998) with satellite SST and SST gradient maps was found. (C) 2003 Elsevier B.V. All rights reserved.BELCANT

Práticas educativas: perspectivas que se abrem para a Educação Especial Educative practices: perspectives that open to the especial education

O objetivo desse texto é registrar reflexões que permitam uma maior compreensão do conceito de simbolização para introduzir a questão da constituição do sujeito simbólico, comprometido pela deficiência mental. As reflexões passam por encontros com diferentes autores, de áreas diversas do conhecimento, com a intenção de marcar a escolha da perspectiva histórico-cultural como a que melhor responde às interrogações sobre o ser humano capaz de dar significado ao mundo, mesmo quando impedido por problemas orgânicos. São fundamentais as contribuições de Vigotski e Bakhtin que concebem o homem como ser que significa e se constitui nas relações concretas de vida.<br>This text objective is to register reflections that permits a major understanding of the symbolization concept to introduce the issue of the symbolic subject constitution, implicated by mental deficiency. The reflections pass by meetings with different authors, from different areas of knowledge having the intention of making the choice of the historical-cultural perspectives with the one that best answers to the interrogations about the human being capable of giving meaning to the world, even being stopped by organic problems. The Vigotski and Bakhtin's contributions are fundamental. They conceive man as a being that signifies and constitutes himself in the concrete relations of life