Reflexos do Mercosul na indústria publicitária brasileira

O presente artigo procede aum balanço geral dosmercados publicitários dospaíses membros do Mercosule examina a presença dasagências de propaganda eempresas de comunicaçãobrasileiras no quarto maiorbloco econômico do planeta.P a l a v r a s - c h a v e s :Mercosul, publicidade, mídi

Role of haemoglobin in the protection of cultured lymphocytes against diepoxybutane (DEB), assessed by in vitro induced chromosome breakage.

Mutat Res. 2003 Apr 20;536(1-2):61-7. Role of haemoglobin in the protection of cultured lymphocytes against diepoxybutane (DEB), assessed by in vitro induced chromosome breakage. Porto B, Chiecchio L, Gaspar J, Faber A, Pinho L, Rueff J, Malheiro I. Laboratory of Cytogenetics, Instituto Ciências Biomédicas Abel Salazar (ICBAS), Largo do Prof. Abel Salazar, No. 2, 4099-003, Porto, Portugal. Abstract Diepoxybutane (DEB) is an alkylating agent that can be used to assess chromosome instability in repair-deficient subjects. Previous authors investigated the role of red blood cells (RBC) in determining individual susceptibility to DEB in normal healthy donors, and demonstrated that a polymorphic enzyme in RBC, Glutathione S-transferase T1 (GSTT1), is involved in DEB detoxification. In the present work we studied the influence of individual GSTM1 and GSTT1 genotypes and the presence of RBC on the frequency of DEB-induced chromosome breakage in lymphocyte cultures from normal individuals and, in particular, the influence of isolated components of RBC: RBC membranes, RBC lysate, and haemoglobin. Our results confirm that individual GSTT1 genotypes modulate the level of genetic lesions induced by DEB; however, this effect was not sufficient to explain the highly significant variation in chromosome breakage between whole blood and RBC-depleted cultures. We showed that RBC can protect cultured lymphocytes against chromosome breakage induced by DEB and we demonstrated the particular role of haemoglobin in the protective effect. PMID: 12694746 [PubMed - indexed for MEDLINE

Monitoring the salt marsh vegetation and flora of the Baixo Vouga Lagunar (Ria of Aveiro, Portugal)

El carácter transicional de la Ría de Aveiro le confiere una riqueza florística singular, integrando comunidades vegetales típicas de las regiones Eurosiberiana y Mediterránea. La implantación del Proyecto Desenvolvimento Agrícola do Vouga (PDAV) va a provocar una modificación de las tasas de encharcamiento y una reducción gradual de la salinidad, factores ecológicos determinantes para muchas de las comunidades halófilas y helofíticas. El presente trabajo pretende contribuir a un mejor conocimiento de la tipología de la vegetación local, que sirva como base para desarrollar un programa de monitorización adecuado que detecte las alteraciones en los patrones espacio- temporales de la vegetación de los sistemas húmedos. Teniendo como objetivo seleccionar los puntos de muestreo donde instalar las parcelas permanentes de monitorización, se realizó una caracterización de la flora y la vegetación a través de trece transectos utilizando una aproximación simplificada al método de Braun- Blanquet. Una vez identificados los tipos de vegetación - en función de su composición florística, corología y ecología - fueron seleccionados al azar inventarios representativos de cada tipo, en los que han sido instaladas dichas parcelas.The transitional biogeographic character of the Ria de Aveiro lagoon area confers it a singular floristic richness, integrating plant communities typical for the Eurosiberian as well as Mediterranean Region. The implementation of the Agricultural Development Plan of the Lower Vouga area (PDAV) in the near future is expected to result in noticeable changes in the tidal submersion regime and a gradual reduction of salinity levels, which are determining ecological factors for many of the halophytic and helophytic plant communities. The present work pretends to contribute to a better knowledge of the local vegetation types and, thereby, to the implementation of an adequate monitoring programme for detecting changes in the spatio-temporal vegetation patterns of the wetlands. With the objective to select the locations for the installation of permanent quadrats, the vegetation of the wetlands was described along 13 transects using a simplified Braun-Blanquet approach. A total of 24 local vegetation types were recognised, 23 of which were selected for the current monitoring programme

Universal Critical Behavior of Aperiodic Ferromagnetic Models

We investigate the effects of geometric fluctuations, associated with aperiodic exchange interactions, on the critical behavior of $q$-state ferromagnetic Potts models on generalized diamond hierarchical lattices. For layered exchange interactions according to some two-letter substitutional sequences, and irrelevant geometric fluctuations, the exact recursion relations in parameter space display a non-trivial diagonal fixed point that governs the universal critical behavior. For relevant fluctuations, this fixed point becomes fully unstable, and we show the apperance of a two-cycle which is associated with a novel critical behavior. We use scaling arguments to calculate the critical exponent $\alpha$ of the specific heat, which turns out to be different from the value for the uniform case. We check the scaling predictions by a direct numerical analysis of the singularity of the thermodynamic free-energy. The agreement between scaling and direct calculations is excellent for stronger singularities (large values of $q$). The critical exponents do not depend on the strengths of the exchange interactions.Comment: 4 pages, 1 figure (included), RevTeX, submitted to Phys. Rev. E as a Rapid Communicatio

From Bloch Oscillations to a Steady-State Current in Strongly Biased Mesoscopic Devices

It has long been known that quantum particles in a periodic lattice exhibit an oscillatory motion that is solely driven by a constant and uniform force field. In a strongly biased mesoscopic device, this would appear as an ongoing time-dependent current oscillation (a Bloch oscillation) but, even when electrons can move coherently and without scattering, a steady-state regime of charge transport (a Landauer current) have been seen to quickly emerge. Here, we theoretically investigate the non-equilibrium current dynamics of a strongly biased two-terminal mesoscopic device, in order to show that such a system can exhibit Bloch oscillations as a transient regime that relaxes into a Landauer steady-state from charge being drained into the leads. Analytical results from the one-dimensional Wannier-Stark ladder problem are combined with numerical quantum time-evolution of a tight-binding toy model with finite leads to characterize the decay times of transient Bloch oscillations and establish the conditions under which they can occur.Comment: Preliminary Version (13 pages + 12 Figures). Comments and Suggestions are Welcome

Ground-motion networks in the Groningen field: usability and consistency of surface recordings

Several strong-motion networks have been installed in the Groningen gas field in the Netherlands to record ground motions associated with induced earthquakes. There are now more than 450 permanent surface accelerographs plus a mobile array of 450 instruments, which, in addition to many instrumented boreholes, yield a wealth of data. The database of recordings has been of fundamental importance to the development of ground-motion models that form a key element of the seismic hazard and risk estimations for the field. In order to maximise the benefit that can be derived from these recordings, this study evaluates the usability of the recordings from the different networks, in general terms and specifically with regards to the frequency ranges with acceptable signal-to-noise ratios. The study also explores the consistency among the recordings from the different networks, highlighting in particular how a configuration error was identified and resolved. The largest accelerograph network consists of instruments housed in buildings around the field, frequently installed on the lower parts of walls rather than on the floor. A series of experiments were conducted, using additional instruments installed adjacent to these buildings and replicating the installation configuration in full-scale shake table tests, to identify the degree to which structural response contaminated the recordings. The general finding of these efforts was that for PGV and oscillator periods above 0.1 s, the response spectral ordinates from these recordings can be used with confidence