Distribution of copper, zinc and cadmium in the southern ocean south of South Africa

Bibliography: leaf 78-83.Analysis and interpretation was carried out on trace metal samples (Cu,Zn,Cd) collected in the Southern Ocean south of South Africa. The results tentatively show that there is a significant copper flux from interstitial waters of the Weddell - Enderby basins. There is little evidence that these trace metals follow the systematics of nutrients throughout the water column; advection appears to play an important role in determining the vertical distribution of these chemical components

Catches in ghost-fishing octopus and fish traps in the northeastern Atlantic Ocean (Algarve, Portugal)

Ghost fishing is the term used to describe the continued capture of fish and other living organisms after a fisherman has lost all control over the gear. Traps may be lost for a variety of reasons including theft, vandalism, abandonment, interactions with other gear, fouling on the bottom (i.e., traps and ropes are caught on rocky substrate), bad weather, and human error (Laist, 1995). Annual trap loss can be as high as 20% to 50% of fished traps in some fisheries (Al-Masroori et al., 2004). Because lost traps can continue to fish for long periods, albeit with decreasing efficiency over time (e.g., Smolowitz, 1978; Breen, 1987, 1990; Guillory, 1993), ghost fishing is a concern in fisheries worldwide

Ant colony optimization routing mechanisms with bandwidth sensing

The study and understanding of the social behavior of insects has contributed to the definition of some algorithms that are capable of solving several types of optimization problems. In 1997 Di Caro and Dorigo developed the first routing algorithm for wired networks, called AntNet, using an approach which was inspired in the behavior of ant colonies. At each node, AntNet, similar to others Ant Colony Optimization (ACO) based algorithms, forward ants based in the amount of pheromones present in the links and in response to the node's queue lengths. In this paper, an adaptation of the e-DANTE algorithm for discrete problems, as an IP based routing mechanism, was implemented. We also propose the inclusion of a new parameter for the computation of paths for both the AntNet and the newly proposed algorithm: the available bandwith. Those methods were tested in ns-2 using two dense network architectures and their efficiency is compared with the original AntNet and a Link-State routing algorithm, when considering the transmission of competing traffic flows between distinct nodes. © 2011 IEEE

Convergence insufficiency and accommodative insufficiency in children

Purpose: Convergence and accommodative insufficiency represent the main cause of complaints during close visual work and can reduce visual performance and comfort. Knowing their prevalence among schoolchildren is fundamental to define strategies for action. The purpose of this study was to estimate the frequency of these conditions in children in 5th and 6th school years in inland Portugal and to assess the impact that each visual condition has on their quality of life, based on the level of visual symptoms. Methods: a cross-sectional study was carried out with children enrolled in the 5th and 6th school years. 372 children (192 girls) were assessed, with average ages of 10.9 ± 0.9 years. Refractive error and binocular vision assessment, integrating accommodative parameters, were used to analyse the visual condition. Symptoms were quantified using the Portuguese version of the CISS (Convergence Insufficiency Symptom Survey). Results: The prevalence of definite Convergence Insufficiency (CI) in the children assessed was 2%. A prevalence of 6,8% could be considered if clinically significant CI (high suspect and definite categories) cases are accounted. In relation to Accommodative Insufficiency (AI), a frequency rate of 10% was recorded, with 3% of the evaluated children presenting AI and CI simultaneously. The symptoms score was higher in AI than in CI. Conclusions: A frequency of approximately 10% was found for each one of the visual syndromes, and it was verified that visual discomfort is common among teenagers who carry these conditions. In cases of asthenopia, such as headaches and loss of concentration, associated with near vision activities, there is a requirement to evaluate the quality of binocular vision.info:eu-repo/semantics/publishedVersio

A distributed load scheduling mechanism for micro grids

Several protocols have recently been defined for smart grids that enable the communication between electric devices and energy management systems. While these protocols and architectures can already be applied in different fields of micro grids, it is still not clear how the distributed resources and constraints of such electrical grids can be managed in an optimum way. In order to achieve a reduction in electricity costs and maximizing investments made in renewable sources, an optimization mechanism should be used to perform load scheduling, considering different variables such as forecasted power generation curve from renewable sources, different tariffs' rates, electric circuit constraints, user restrictions and correspondent comfort levels. Given these considerations, this work defines and evaluates a distributed micro grid resource management architecture and protocol which is able to optimize load scheduling while considering all the mentioned restrictions and parameters. The proposed architecture was implemented on a multi-agent simulator and the performed tests show that significant reductions in electricity cost can be achieved using this methodology. © 2014 IEEE

Sintra vegetation and landscape

The field trip to Sintra region, as part of the 48th IAVS Symposium, aims to illustrate well-preserved and representative plant communities of Sintra municipality. It consists of two short field stops and a 3 km wal

Macrofauna assemblages in a XVIIth century shipwreck: comparison with those on natural reefs and sandy bottoms

The macrofauna assemblages of a XVIIth century shipwreck off southern Portugal were studied and compared with those of nearby natural reefs and sandy bottoms, by underwater visual census. A total of 11 173 specimens of 224 different fauna taxa and 12 phyla were recorded. Natural reefs had the highest density of specimens (35 122 / 1000 m2) followed by the shipwreck (21 392 / 1000 m2) and the sandy bottoms (3771 / 1000 m2). Three biodiversity indices were estimated (Margalef, Shannon- Wiener and Pielou), with the natural reefs showing the highest values. However, the shipwreck presented values relatively similar to those of the natural reefs for the Shannon-Wiener and Pielou indices. The three habitats were clearly distinguishable by multivariate statistical analysis, with the average dissimilarity between sand and shipwreck, and between sand and natural reefs being much higher than that between the shipwreck and the natural reefs. The shipwreck had higher abundances of some commercially important species, such as the pouting Trisopterus luscus, European conger Conger conger, and common spider crab Maja squinado, as well as some vulnerable and threatened species such as the pink seafan Eunicella verrucosa. The results presented emphasize the importance of this habitat on the southern Portuguese coast.info:eu-repo/semantics/publishedVersio

Ichthyofauna assemblages from two unexplored Atlantic seamounts: Northwest Bank and João Valente Bank (Cape Verde archipelago)

Underwater censuses by divers were used to study the fish assemblages from two unexplored Atlantic seamounts in the Cape Verde archipelago. Fifty three species of 27 families were recorded: 27 in Northwest Bank and 46 in João Valente Bank. Northwest Bank had dense schools, while João Valente Bank had higher species richness and smaller schools. Both seamounts were dominated mainly by coastal species directly depending on seabed habitat (Demersal or benthopelagic). Of the 53 fish species recorded, 22.6% were of continental African origin, while 9.4% and 5.7% were endemic of the Cape Verde Islands and of the Macaronesia province, respectively. Most species (64.2%) had a very wide biogeographic distribution: cosmopolitan (22.6%), amphi-Atlantic (28.3%) and Atlantic-Mediterranean (13.2%). Northwest Bank and João Valente Bank may have a permanent fish community supported by various oceanographic-topographic interactions. João Valente Bank seems more diverse, which is probably associated with algae cover and with a larger area providing additional suitable and more varied habitats. The geographic proximity to the coast and the presence of oceanic and/or oceanodromous species suggests that the upper part of these seamounts may act both as attraction points and as “stepping-stones” for the dispersal of coastal species.info:eu-repo/semantics/publishedVersio