Browsing by Issue Date, starting with "2009-05"
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- Desenvolvimento regional e investimento rodoviário em Portugal: o caso das auto-estradas SCUTPublication . Pereira, Alfredo; Andraz, Jorge MiguelEste livro corresponde ao primeiro de uma série de três obras e responde a uma proposta da Associação Portuguesa para o Desenvolvimento Regional junto dos seus associados para a realização de três estudos sobre temas importantes para o desenvolvimento regional em Portugal: um primeiro sobre os problemas emergentes para o desenvolvimento regional, outro sobre casos de desenvolvimento regional e um terceiro sobre modelos operacionais de desenvolvimento regional. O objectivo desta primeira obra é responder a questões emergentes para a problemática do desenvolvimento regional em Portugal nomeadamente as que se relacionam com os impactos territoriais que resultam de alterações profundas no movimento de pessoas, de capital, de energia e de mercadorias estimuladas por fenómenos globais.
- Multi-node processing for asymmetrical communications in underwater acoustic networksPublication . Silva, A.; Huillery, J.; Jesus, S. M.Underwater acoustic communication networks have attracted attention for its applications in many areas such as mine warfare, rapid environmental assessment or search and rescue, where there is the need for conserted action of a group of observers/actuators. A common requirement in most of these applications is the need to make accessible to the global (terrestrial/aerial) user network large amounts of critical underwater collected data. This paper addresses this requirement by using multichannel nodes providing an asymmetrical point-topoint (P2P) connection where the upload link has a much higher data rate than the download link. The emphasis of this work is not so much on the final channel throughput but on establishing the optimal processing of spatially distributed multichannel nodes that serve as interface between the underwater nodes and the global/user network. The adopted strategy relies on passive time-reversal which can be viewed as a spatial pre-equalizer for each multichannel node. Then an intersymbol interference optimal combination of various nodes is divised for balancing poor communications of one or more nodes in the network. The method and techniques are theoretically derived and applied to real data acquired with a network of 2 surface buoys over an environmentally challenging area off the coast of Portugal in July 2007.
- Embeddings of variable Hajlasz-Sobolev spaces into holder spaces of variable orderPublication . Almeida, Alexandre; Samko, StefanPointwise estimates in variable exponent Sobolev spaces on quasi-metric measure spaces are investigated. Based on such estimates, Sobolev embeddings into Holder spaces with variable order are obtained. This extends some known results to the variable exponent setting. (C) 2008 Elsevier Inc. All rights reserved.
- Frayed at the edges: selective pressure and adaptive response to abiotic stressors are mismatched in low diversity edge populationsPublication . Pearson, Gareth; Lago-Lestón, Asunción; Mota, CatarinaTheory predicts that population structure and dynamics affect a population's capacity for adaptation to environmental change. For isolated, small and fragmented populations at the trailing edge of species distributions, loss of genetic diversity through random genetic drift may reduce adaptive potential and fitness levels for complex traits. This has important consequences for understanding population responses to, for example changing climate, but has rarely been tested in natural populations. We measured the intertidal thermal environment and tidal exposure (emersion) times for natural populations of the intertidal seaweed Fucus serratus at the centre (southwest UK) and southern edge (northern Portugal) of its range in the Eastern Atlantic, and for a congener, F. vesiculosus, whose range extends further south to Morocco. Fitness-related traits of individuals at each location were measured in common garden experiments: physiological resilience to desiccation and heat shock (PSII quantum yield), and the molecular phenotype of the heat shock response (quantitative PCR of heat shock protein gene transcripts). The realized thermal environment experienced by F. serratus was similar at the centre and southern edge of its distribution because the maximum shore height (and emersion period) was reduced in southern populations. For F. vesiculosus, thermal maxima were higher and occurred more frequently in the south, although maximum vertical height (emersion time) remained similar to central populations. Edge populations of F. serratus were less resilient to desiccation and heat shock than central populations, and expression of heat shock genes was higher at the same temperature, suggesting greater cellular stress. In contrast, there was no evidence for physiological divergence in heat shock response in F. vesiculosus, and little variation in gene expression. Synthesis. We provide evidence that compared with range-centre populations upper intertidal limits of F. serratus at the southern edge are 'pruned back' by abiotic stressors. Rather than being locally adapted, these small populations are less resilient to abiotic stresses and experience greater cellular stress during heat shock. These results suggest that ongoing climate forcing factors may threaten small, fragmented rear edge populations because of inherently reduced fitness and lower adaptive capacity relative to larger central populations.
- Contributos do director de turma para a relação escola-famíliaPublication . Alho, Susana; Nunes, CristinaO presente artigo pretende divulgar os resultados de uma investigação desenvolvida numa escola básica em que se construíram e aplicaram instrumentos; questionários, entrevistas e análise de alguns documentos produzidos pela escola que permitissem perceber que iniciativas toma o director de turma para conhecer as famílias dos alunos. De uma maneira geral, todos os actores educativos consideraram que o director de turma pode contribuir para que a escola conheça melhor as famílias dos alunos. Como estratégias propiciadoras de resultados positivos os directores de turma referiram: os atendimentos individuais, as reuniões de encarregados de educação e os inquéritos realizados aos alunos.
- A new method for the study of essential fatty acid requirements in fish larvaePublication . Morais, Sofia; Conceicao, LuisThis study describes a methodology with potential application in the estimation of essential fatty acid (EFA) requirements of fish larvae. Senegalese sole (Solea senegalensis) larvae were fed, from 16 days after hatching (DAH), on Artemia enriched with different oils, inducing graded dietary concentrations of DHA: (1) soyabean oil, containing no measurable amounts of DHA (NDHA); (2) fish oil, inducing a medium DHA level (MDHA, 3 g DHA/100 g fatty acids); and (3) a mixture of Easy DHA Selco and Microfeed, resulting in high DHA content (HDHA, 8 g/100 g). At 28 DAH a metabolic trial was conducted where larvae were tube fed [1-(14) C]DHA, in order to determine its absorption, retention in the gut and body tissues, as well as its oxidation. At 23 DAH the HDHA treatment induced a significantly higher larval growth, while at 32 DAH significant differences were only found between the NDHA and HDHA treatments. The absorption of tube-fed [1-(14) C]DHA was extremely high (94-95%) and independent of feeding regime. However, in larvae fed NDHA Artemia, a significantly higher amount of label was retained in the gut compartment and a concurrently lower retention was measured in the body. A significantly higher proportion of the absorbed DHA label was oxidized in larvae fed HDHA, compared to NDHA. Based on these results, we suggest that increasing dietary supply of DHA above the larval requirement level results in its increased oxidation for energy purposes and we propose potential applications of the tube feeding methodology using radiolabelled EFA in conjunction with dose-response studies.
- Ontogeny of critical swimming speed of wild-caught and laboratory-reared red drum Sciaenops ocellatus larvaePublication . Faria, Ana M.; Ojanguren, Alfredo F.; Fuiman, Lee A.; Gonçalves, Emanuel J.Critical swimming speed (U,,it) provides a useful estimate of maximum swimming performance for fish larvae that can be used to assess transport and migratory potential. We measured U,it of red drum Sciaenops ocellatus larvae through its ontogeny and compared the swimming performance of laboratory-reared larvae to that of wild-caught individuals. U-crit increased with ontogeny (size), even though variability in U-crit at any ontogenetic state was large. U-crit for wild-caught larvae increased from 9.7 to 22.2 cm s(-1) over the range of 8.3 to 16.3 mm TL and from 1.1 to 20.5 cm s(-1) over the range of 3.0 to 19.1 mm TL for reared larvae. The ontogenetic increase in critical swimming speed occurred in 2 phases-an early phase of rapid improvement, and a later phase of slower improvement. This sharp change in the trajectory of swimming performance coincided with important changes in ecology, morphology, and hydrodynamics. During the early phase, larvae were pelagic, their growth was highly allometric, especially in the caudal region, and they swam in the inertial hydrodynamic regime. The onset of the later phase coincided with settlement into seagrass beds, isometric growth, and inertial effects on locomotion. Wild larvae generally exhibited greater values of U,it than reared larvae of a comparable size, but the difference was not statistically significant. The results of this comparison imply that research on reared larvae may provide naturalistic results for swimming performance and that hatchery-produced larvae may perform certain behaviours well when released into the wild.
- Diversity of bacteria in the marine sponge Aplysina fulva in Brazilian coastal watersPublication . Hardoim, C. C. P.; Costa, R.; Araujo, F. V.; Hajdu, E.; Peixoto, R.; Lins, U.; Rosado, A. S.; van Elsas, J. D.Microorganisms can account for up to 60% of the fresh weight of marine sponges. Marine sponges have been hypothesized to serve as accumulation spots of particular microbial communities, but it is unknown to what extent these communities are directed by the organism or the site or occur randomly. To address this question, we assessed the composition of specific bacterial communities associated with Aplysina fulva, one of the prevalent sponge species inhabiting Brazilian waters. Specimens of A. fulva and surrounding seawater were collected in triplicate in shallow water at two sites, Caboclo Island and Tartaruga beach, Buzios, Brazil. Total community DNA was extracted from the samples using "direct" and "indirect" approaches. 16S rRNA-based PCR-denaturing gradient gel electrophoresis (PCR-DGGE) analyses of the total bacterial community and of specific bacterial groups-Pseudomonas and Actinobacteria-revealed that the structure of these assemblages in A. fulva differed drastically from that observed in seawater. The DNA extraction methodology and sampling site were determinative for the composition of actinobacterial communities in A. fulva. However, no such effects could be gleaned from total bacterial and Pseudomonas PCR-DGGE profiles. Bacterial 16S rRNA gene clone libraries constructed from directly and indirectly extracted DNA did not differ significantly with respect to diversity and composition. Altogether, the libraries encompassed 15 bacterial phyla and the candidate division TM7. Clone sequences affiliated with the Cyanobacteria, Chloroflexi, Gamma-and Alphaproteobacteria, Actinobacteria, Bacteroidetes, and Acidobacteria were, in this order, most abundant. The bacterial communities associated with the A. fulva specimens were distinct and differed from those described in studies of sponge-associated microbiota performed with other sponge species.
- Public Libraries: techno trends and collective memoryPublication . Mariano, Alexandra de Brito; Dias, MiguelBy public library I mean here a library providing some kind of universal access to its assets, one whose readership isn’t exclusively tied and restricted to a particular organization – including the generally called public libraries, but also many specialized libraries, such as the academic of the open kind. Despite all efforts, public libraries continue to face strong barriers to their participation in the information society. Participants of the World Meeting on the Future of the ISIS Software recognized that “the ISIS Software Family has a unique technological concept and developmental mission to cope with Information Storage and Retrieval Systems (ISRS), particularly for developing countries where the technology is widely known and used; that the ISIS Software Family has now fully embraced the Free and Open Source Software approach and the support of UNICODE structures to be fully open and multilingual” (Rio Declaration 2008), restating thus the persistent relevance of this software family. OSS (Coar 2006) is defined as software whose source code is freely available, therefore allowing for free inspection and/or utilization, i.e., it is available for study and use by everyone without any payment or any other barrier to access. the lack of technical skill in libraries, a situation that libraries share with much of the public and cultural sectors. The study of OSS ILS, and of the their adaptation to the needs of specific public libraries may be the solution to this. Library Management Systems) that enhances digital archive interoperability between a diverse range of libraries.