Vertical crustal motion along the Mediterranean and Black Sea coast derived from ocean altimetry and tide gauge data

Tide gauge (TG) data along the northern Mediterranean and Black Sea coasts are compared to the sea-surface height (SSH) anomaly obtained from ocean altimetry (TOPEX/Poseidon and ERS-1/2) for a period of nine years (1993–2001). The TG measures the SSH relative to the ground whereas the altimetry does so with respect to the geocentric reference frame; therefore their difference would be in principle a vertical ground motion of the TG sites, though there are different error sources for this estimate as is discussed in the paper. In this study we estimate such vertical ground motion, for each TG site, from the slope of the SSH time series of the (non-seasonal) difference between the TG record and the altimetry measurement at a point closest to the TG. Where possible, these estimates are further compared with those derived from nearby continuous Global Positioning System (GPS) data series. These results on vertical ground motion along the Mediterranean and Black Sea coasts provide useful source data for studying, contrasting, and constraining tectonic models of the region. For example, in the eastern coast of the Adriatic Sea and in the western coast of Greece, a general subsidence is observed which may be related to the Adriatic lithosphere subducting beneath the Eurasian plate along the Dinarides fault.

The imprint of the crustal magnetic field on the thermal spectra and pulse profiles of isolated neutron stars

Isolated neutron stars (NSs) show a bewildering variety of astrophysical manifestations, presumably shaped by the magnetic field strength and topology at birth. Here, using state-of-the-art calculations of the coupled magnetic and thermal evolution of NSs, we compute the thermal spectra and pulse profiles expected for a variety of initial magnetic field configurations. In particular, we contrast models with purely poloidal magnetic fields to models dominated by a strong internal toroidal component. We find that, while the former displays double-peaked profiles and very low pulsed fractions, in the latter, the anisotropy in the surface temperature produced by the toroidal field often results in a single pulse profile, with pulsed fractions that can exceed the 50–60 per cent level even for perfectly isotropic local emission. We further use our theoretical results to generate simulated ‘observed’ spectra, and show that blackbody (BB) fits result in inferred radii that can be significantly smaller than the actual NS radius, even as low as ∼1–2 km for old NSs with strong internal toroidal fields and a high absorption column density along their line of sight. We compute the size of the inferred BB radius for a few representative magnetic field configurations, NS ages and magnitudes of the column density. Our theoretical results are of direct relevance to the interpretation of X-ray observations of isolated NSs, as well as to the constraints on the equation of state of dense matter through radius measurements.

O patrimônio invisível: arquitetura popular urbana de municípios do período colonial brasileiro

No Brasil, ações institucionais de preservação de bens imóveis tem foco principal na arquitetura erudita, colocando em segundo plano de importância a arquitetura produzida por indivíduos com formação escassa e empírica. Este trabalho contribui para o reconhecimento da arquitetura popular (vernácula) como patrimônio cultural. Trabalha-se na criação de acervo fotográfico de edificações e equipamentos urbanos produzidos durante o período colonial, nos municípios de Tiradentes, Mariana, Ouro Preto e Diamantina (Minas Gerais). São realizadas visitas in loco para reconhecimento e seleção de objetos a serem fotografados. O registro fotográfico é realizado com câmera digital reflex de objetiva simples, privilegiando-se objetos cuja deterioração permite a observação de materiais e técnicas construtivas. Como resultado parcial da pesquisa, foram produzidas 4.522 imagens, documentando o abandono de edificações residenciais e chafarizes setecentistas e oitocentistas, bem como a descaracterização de exemplares de edificações coloniais populares habitadas, cujas paredes de adobe e pau-a-pique são substituídas por alvenaria de tijolos pelos moradores. Tornam-se necessárias ações para o reconhecimento – no âmbito do Poder Público e das comunidades locais – da relevância histórica da arquitetura popular, entendida como produto articulado e coerente de contribuições das culturas distintas que formaram essa região do Brasil.