Browsing by Issue Date, starting with "2008-07"
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- Genetic differentiation and secondary contact zone in the seagrass Cymodocea nodosa across the Mediterranean-Atlantic transition regionPublication . Alberto, F.; Massa, S. I.; Manent, P.; Diaz-Almela, E.; ARNAUD-HAOND, Sophie; Duarte, C. M.; Serrão, EsterAim A central question in evolutionary ecology is the nature of environmental barriers that can limit gene flow and induce population genetic divergence, a first step towards speciation. Here we study the geographical barrier constituted by the transition zone between the Atlantic Ocean and the Mediterranean Sea, using as our model Cymodocea nodosa, a seagrass distributed throughout the Mediterranean and in the Atlantic, from central Portugal to Mauritania. We also test predictions about the genetic footprints of Pleistocene glaciations. Location The Atlantic–Mediterranean transition region and adjacent areas in the Atlantic (Mauritania to south-west Portugal) and the Mediterranean. Methods We used eight microsatellite markers to compare 20 seagrass meadows in the Atlantic and 27 meadows in the Mediterranean, focusing on the transition between these basins. Results Populations from these two regions form coherent groups containing several unique, high-frequency alleles for the Atlantic and for the Mediterranean, with some admixture west of the Almeria–Oran Front (Portugal, south-west Spain and Morocco). These are populations where only one or a few genotypes were found, for all but Cadiz, but remarkably still show the footprint of a contact zone. This extremely low genotypic richness at the Atlantic northern edge contrasts with the high values (low clonality) at the Atlantic southern edge and in most of the Mediterranean. The most divergent populations are those at the higher temperature range limits: the southernmost Atlantic populations and the easternmost Mediterranean, both potential footprints of vicariance. Main conclusions A biogeographical transition region occurs close to the Almeria–Oran front. A secondary contact zone in Atlantic Iberia and Morocco results from two distinct dispersal sources: the Mediterranean and southernmost Atlantic populations, possibly during warmer interglacial or post-glacial periods. The presence of high-frequency diagnostic alleles in present-day disjunct populations from the southernmost Atlantic region indicates that their separation from all remaining populations is ancient, and suggests an old, stable rear edge.
- Feasibility of confined masonry design in AzoresPublication . Braga, Alfredo Manuel Gonçalves Silva; Estêvão, João Manuel CarvalhoIn the recent years, small size buildings built with resistant confined masonry demonstrated an acceptable behaviour due to earthquakes actions. On the other hand, many experimental studies have been corroborating these findings. As proved in recent work, and according to the Eurocodes, the security can not be accomplished when using confined masonry made with Portuguese traditional clay units. In this context, the aim of the present work was to determine the feasibility of construction using confined masonry, in small buildings, made with hollow aggregate concrete units and designed according to Eurocodes 6 and 8. These results can be relevant for the Azores because this type of construction is still being used in the region. The structural evaluation of the dwellings is supported on tests made at the laboratories of Civil Engineering Department of University of Algarve, mainly to characterize the shear strength of masonry. The contribution of cement render to the shear resistance of confined masonry was also verified.
- Effect of simulated purse seine fishing on acclimated sardines and post-fishing interactions with predatorsPublication . Marçalo, A.; Araújo, J.; Pousão-Ferreira, P.; Erzini, Karim; Stratoudakis, Y.The fate of fish deliberately released (slipped) during purse seining is poorly studied and estimating unaccounted mortality rates in pelagic fisheries has been difficult and imprecise.
- Caracterizaçao da pesca recreativa de costa sul e sudoeste de PortugalPublication . Erzini, KarimTrammel net fisheries were studied in four areas: the Cantabrian Sea (Basque Country, Spain), the Algarve (Southern Portugal), the Gulf of Cádiz (Spain) and the Cyclades Islands (Greece). Surveys were carried out in order to identify trammel net métiers and to characterise the gear used. Trammel nets were among the most important gears used in the small-scale fisheries, with up to 9 different métiers identified in each area. The most important métiers in the Algarve and the Gulf of Cádiz were those for cuttlefish (Sepia officinalis) and soles (Solea senegalensis, Microchirus azevia, Synaptura lusitanica). In the Cantabrian Sea, sole (Solea vulgaris), shellfish (several species) and scorpion fish (Scorpaena spp.) métiers dominated while a variety of species where targeted in the multi-species trammel net fishery in the Cyclades. In each area, experimental trammel nets of six different types (combinations of 2 large mesh outer panel sizes and 3 small mesh outer panels) corresponding to the most common métier, were constructed and fishing trials carried out on a seasonal basis (4 seasons in the Cantabrian Sea, Algarve and Cyclades and 2 in the Gulf of Cádiz) using chartered commercial fishing vessels. Overall, 271, 360, 185 and 185 km of trammel nets were fished in the experimental fishing trials in the Cantabrian Sea, Algarve, Gulf of Cádiz and Cyclades Islands respectively.
- The quality of the training experience: predictor variables of career explorationPublication . Gamboa, Vitor; Paixão, Maria Paula; Jesus, SaúlMany young people attending secondary education will do an apprenticeship by the end of their training, which will come as a new context of learning. The quality of this new context can have differentiated impacts on student’s lives and on their vocational development. For many students, it can be their first formal and structured contact with the workplace – experiencing a reality that, until then, has always been mediated by other sources and agents of information. Authors like Ducat (1980), Brooks et al. (1995) and Super (1963) evoke the value of work experience as the most realistic way of vocational exploration. However, the efficiency of work experiences is extremely variable (Ainley, P., 1990; Smith & Harris, 2000) and seems to depend significantly on factors like supervision, feedback, autonomy, learning opportunities and peer support. Several studies suggest that the quality of the work experience and the exploratory behavior associated to this have a considerable influence on the vocational development (e.g. Brooks et al.,1995; Carless & Prodan, 2003; Loughlin & Barling, 1998; Mortimer, 2003; Vondracek, 1997). The present study seeks to highlight which qualities of the apprenticeship are predictors of career exploration in a group of students attending the 12th grade.