Detrital zircon from a late Paleozoic accretionary complex of SW Iberia (Variscan Belt): History of crustal growth and recycling at the Rheic convergent margin

In this study we present new U-Pb ages of detrital zircons from greywackes and quartzites of the Pulo do Lobo Anticline (PLA) that have been interpreted to represent a Late Paleozoic accretionary complex in SW Iberia. The PLA separates the Ossa Morena Zone, which has a North- Gondwana affinity throughout Late Ediacaran and Early Paleozoic times, from the South Portuguese Zone, which is considered to be underlain by Laurussia basement. The PLA stratigraphy most likely represents a synorogenic basin that records the closure of the Late Paleozoic Rheic Ocean and the amalgamation of Pangaea. The youngest formations of the PLA contain upper Devonian microfossils.The results obtained indicate that the detrital zircons from the PLA represent a wide range of Precambrian and Paleozoic crystallization ages. Recycling of older sedimentary units of the Late Ediacaran active margin (Cadomian/Pan-African orogenies) as well as of the Early Paleozoic rifting and passive margin (Rheic Ocean) stages, accounts for the older populations with North-Gondwana affinity (Cambrian, Neoproterozoic, Paleoproterozoic and Archean, with a gap of Mesoproterozoic-age). However, the Mesoproterozoic detrital zircon ages found in the greywackes of the Pulo do Lobo Formation (< 7%) that do not correspond to any substantial source within North-Gondwana, could come from recycled sedimentary deposits or from denudation of Grenville-age basement (Laurussia?). The more recent formations present in the northern limb (Ferreira-Ficalho Group) of the PLA show a significant age cluster in the upper Devonian (c. 378 Ma), whereas on the southern limb (Chança Group), samples have from base to top of the stratigraphic sequence: a minor age cluster in the middle Devonian (c. 390 Ma), a significant age cluster in upper Devonian (c. 380 Ma) and very significant age cluster in the upper Devonian (c. 372 Ma). The presence of middle-upper Devonian detrital zircons in combination with very low abundances of Mesoproterozoic detrital zircon suggests that the PLA sedimentary rocks were not derived from exotic sources but rather have a North-Gondwanan origin. The zircon population in the interval c. 390-380 Ma has no identified corresponding magmatic or stratigraphic source in SW Iberia. Considering that, during the development of the upper Devonian basins of SW Iberia, Laurussia basement was not exposed and that there was no magmatic arc on the North-Gondwana margin, we suggest that the c. 390- 380 Ma detrital zircons are most probably derived from denudation of a (intra-oceanic) magmatic arc related to the closure of the Rheic Ocean

Heaven on Earth. On systematicity and aesthetic pleasure

In addition to its intense and innovative cosmological dialogue with predecessors, Kant’s Theory of the Heavens (1755) and its systematising goal tell us something more about the young Kant’s thoughts concerning humanity and the world. We intend 1) to show how Kant’s approach to the question of the order of the universe fi nds a middle path between the extremes of theology and naturalism; b) to show how purposiveness [Zweckmäβigkeit] exemplifies this middle path, and how this progressive resistance is a theoretical device to which Kant would frequently resort; c) to examine the extent to which the discernment of purposiveness and its theoretical order are felt by us as a singular aesthetic pleasure

Micro-EDXRF, SEM-EDS and OM characterisation of tin soldering found in handle attachments of Roman situlae from Conimbriga (Portugal)

Tin (Sn) or a Sn-rich solder applied to copper-based artefacts has been frequently used at least, since the Ancient Greece, although scarce studies have been published concerning the technology of this metallurgical joining technique. Several filler remnants were reported to be found in a Roman collection of handle attachments of situlae or cauldrons (2nd century BCE–5th century CE) from the archaeological site of Conimbriga, a Roman city from the Lusitania Province (Portugal). All these artefacts were cast in high leaded coppers and bronzes. The present study aims to contribute to the knowledge of Sn-rich soldering, an ancientmetallurgical joining technique, by the characterisation of the fusible metallic alloy present in 10 Roman artefacts by means of micro-energy dispersive X-ray fluorescence spectrometry (micro-EDXRF), scanning electron microscopy with energy dispersive X-ray (SEM-EDS) microanalysis and optical microscope (OM) observations. Results of studied solders show the presence of Cu-Sn alloys, with Sn contents ranging from δ to η phase composition (30–60wt% Sn). As the attachments were made in leaded copper alloys, it was also observed, in some cases, the melting of the interdendritic Pb-rich chains with long-range diffusion of the solder alloy into the substrate. The fillers compositions suggest that the handle attachments have been joined to a situla body by the soldering metallurgical process with Sn or a Sn-rich alloy. The studied leaded Cu-Sn attachments, probably formulated by local craftsman, were joined into the body of a situla or cauldron with a soft solder (soldering), a common metallurgical joint from Antiquity, although no relation was found between composition or typology and the Sn or Sn-rich solder

Teaching materials in the 21st century

We live in an era of continuous change. In the branch of engineering, beyond the usual and pressing objectives of functionality, safety and integrity, computers are now used pervasively, new economic pressures and concern for the environment are looming, and the availability of energy resources and proper functioning of materials supply chains are ever more important. Students need an education that allows them to understand and deal with these changes, in a time when growth in the number of students, expectations and pressure on teaching resources is a challenge for professors, particularly for younger academics. Engineers create things out of materials. What do engineering students need to know to select and use materials that perform as expected, are safe, economically efficient and have the least environmental impact? This question leads to the introduction of the design approach. Knowledge, data and tools are necessary for students to make decisions that meet complex design requirements. This means that science is introduced in a way that facilitates understanding how to meet design requirements and select materials and processes. This paper also introduces briefly some of the new aspects of the 2012 CES EduPack. This tool developed by Granta Design, supports professors and helps students of both introductory and advanced courses in branches such as engineering, design and science in the study of materials. CES EduPack is used in more than 850 universities and institutes around the world and is continually evolving to offer a new version each January. Changes and new features are focused on two pathways, one active (eg development of Eco Selector and Eco-audit tool) and another in response to feedback from users. The latter has made the software more intuitive and easy to use.Peer Reviewe

Marine Cyanophytes from the Western Cape, South Africa: Chroococcales

Forty taxa of marine Chroococcales (Cyanophyceae) belonging to six families (Microcystaceae, Chroococcaceae, Chamaesiphonaceae, Dermocarpellaceae, Xenococcaceae and Hydrococcaceae) and 18 genera (Aphanocapsa, Aphanothece, Chamaecalyx, Chroococcidiopsis, Chroococcus, Cyanocystis, Cyanosarcina, Gloeocapsa, Hydrococcus, Hyella, Merismopedia, Microcrocis, Myxosarcina, Pleurocapsa, Stanieria, Stichosiphon, Synechococcus and Synechocystis) have been recorded for the Western Cape, South Africa, Twenty taxa are new records for South Africa; five at the generic level. (Cyanocystis, Synechococcus, Microcrocis, Synechocystis and Stichosiphon), fourteen at the specific level (Aphanothece stagnina, Aphanocapsa sesciacensis, Merismopedia affixa, M. litorale, Gloeocapsa crepidinium, G. cf, gelatinosa, Cyanosarcina cf. chroococcoides, Stanieria sphaerica, Chamaecalyx cf. fucicola, C. cf. suffultus, C cf. swirenkoi, Pleurocapsa crepidinium, P. cf minor and P. cf. minuta) and one at the varietal level (Chroococcus turgidus var. maximus). Morphological and size variability have been recorded and discussed

Time-space distribution of silicic plutonism in a gneiss dome of the Iberian Variscan Belt: The Évora Massif (Ossa-Morena Zone, Portugal)

In the Iberian Variscan Belt, polyphasic deformation has been recognized as comprising an early phase of crustal thickening, followed by an intermediate phase of crustal extension and doming, and a later phase of shortening. The Évora Massif is a gneiss dome of the westernmost domains of the Ossa-Morena Zone (SW Iberia), which provides a remarkable insight into the late Paleozoic deep crustal structure of the Variscan continental crust of northern Gondwana. In this study, we bring new structural and geochronological U-Pb data for the northern hanging-wall of the Évora Massif. We describe the existence of low-dipping D2 extensional shear zones associated with Buchan-type metamorphism (M2); this enables three tectono-metamorphic units to be distinguished: the Lower Gneiss Unit, the Intermediate Schist Unit, and the Upper Slate Unit. D2-M2 structures experienced sub- horizontal shortening (D3) and were transposed by low-plunging folding, thrusting and strike-slip faulting. Zircon grains extracted from Pavia quartz-feldspathic gneiss of the Lower Gneiss Unit yielded a crystallization age of ca. 521 Ma (Cambrian Stage 2–3), which establishes a correlation with tectono-metamorphic units of the footwall and southern hanging-wall of the Évora Massif. U-Pb zircon dating of Divôr foliated quartz-diorite (339 ± 7 Ma), Malarranha weakly foliated biotite-rich granite (322 ± 3 Ma), and undeformed porphyritic granite of the Pavia pluton (314 ± 4 Ma) constrain the timing of emplacement of granitic magmas synchro- nously with doming. Carboniferous magmatism initiated with doming (ME1 - ca. 343–335 Ma), continued through D2-M2 (ME2 - ca. 328–319 Ma), and lasted until the waning stage of crustal extension (ME3 - ca. 317–313 Ma). The Évora Massif gneiss dome probably formed as result of the combined effect of gravitational collapse of the thickened crust and buoyancy-driven gravitational instability developed in the partially molten continental crust influenced by the transfer of heat from rising mantle-derived (i.e. dioritic-gabbroic) magmas rocks found in the footwall of the Évora Massif

Age of the basement beneath the Mesozoic Lusitanian Basin revealed by granitic xenoliths from the Papôa volcanic breccia (West Iberia)

The dyke of the Papôa volcanic breccia cross-cutting the Lower Jurassic sequence of the Lusitanian Basin (West Iberia) contains granitic xenoliths. In this study, for the first time, U-Th-Pb zircon analysis of two xenoliths yielded 298 ± 4 Ma for biotite granite and of 292 ± 2 Ma for two-mica granite, indicating that the pre-Mesozoic basement of the Lusitanian Basin includes Permian intrusions. These ages are close within the margin of error of the age of the Late Carboniferous granites of the Berlengas isle that with the Late Devonian high-grade metamorphic rocks of the Farilhões isles, located northwest of the study area, which form the pre-Mesozoic basement of the Lusitanian Basin. These new geochronological findings enable it to be established that Permo-Carboniferous magmatism lasted at least 13 Ma, in this region of the Appalachian-Variscan belt. Furthermore, a comparison with available data from Paleozoic tectonic units of the Appalachian-Variscan belt located both in the Iberian Massif and outside it enables the suggestion to be made that the Lusitanian Basin (Peniche) most probably rests on the South Portuguese Zone, which may also be correlated with the Rhenohercynian Zone present in southwest England, and the Meguma terrane of Nova Scotia

Age of the basement beneath the Mesozoic Lusitanian Basin revealed by granitic xenoliths from the Papôa volcanic breccia (West Iberia)

The dyke of the Papôa volcanic breccia cross-cutting the Lower Jurassic sequence of the Lusitanian Basin (West Iberia) contains granitic xenoliths. In this study, for the first time, U-Th-Pb zircon analysis of two xenoliths yielded 298±4Ma for biotite granite and of 292±2Ma for two-mica granite, indicating that the pre-Mesozoic basement of the Lusitanian Basin includes Permian intrusions. These ages are close within the margin of error of the age of the Late Carboniferous granites of the Berlengas isle that with the Late Devonian high-grade metamorphic rocks of the Farilhões isles, located northwest of the study area, which form the pre-Mesozoic basement of the Lusitanian Basin. These new geochronological findings enable it to be established that Permo-Carboniferous magmatism lasted at least 13Ma, in this region of the Appalachian-Variscan belt. Furthermore, a comparison with available data from Paleozoic tectonic units of the Appalachian-Variscan belt located both in the Iberian Massif and outside it enables the suggestion to be made that the Lusitanian Basin (Peniche) most probably rests on the South Portuguese Zone, which may also be correlated with the Rhenohercynian Zone present in southwest England, and the Meguma terrane of Nova Scotia

Reducing social inequalities in the oral health of an adult population

The objective of this study was to evaluate the association between social inequality indicators and oral health conditions in an adult population. This prospective cohort study assessed a probabilistic sampling of adults (aged 20-64 years) living in Piracicaba, São Paulo, Brazil. Oral examinations were performed in 2011 and 2015, conducted at home, and used the decay-missing-filled (DMFT) index of permanent teeth, the Community Periodontal Index (CPI), and the visible biofilm criterion. A questionnaire was administered to determine demographic and socioeconomic aspects and dental services used, and collect oral health-related quality of life (OHRQoL) data. Social inequality indicators were evaluated according to social class (high, middle or low) and type of dental service used (public, health insurance or private), and compared with oral health conditions (visible biofilm, DMFT and incidence of tooth loss, periodontal pockets and bleeding, and OHRQoL), evaluated between 2011 and 2015. Analysis using chi-squared or Fisher tests (p < 0.05) and Cochran's Q test was conducted separately for each category analyzed between 2011 and 2015 (p < 0.05). A total of 143 adults who participated in an earlier study were examined after four years of follow-up. Although the occurrence of oral disease did not decrease over the study period (4 years), there was a reduction in inequality among lower social classes in regard to presence of tooth decay and oral health impact on self-perceived quality of life between 2011 and 2015 (p < 0.05). These results suggest that the Brazilian National Oral Health Policy has achieved its principles, especially that of greater equity33COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2014/15184-22009/16560-0; 2011/00545-