Browsing by Author "Silva, C."
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- Cellular location of Prune dwarf virus in almond sections by in situ reverse transcription-polymerase chain reactionPublication . Silva, C.; Tereso, S.; Nolasco, Gustavo; Oliveira, M. M.In situ reverse transcription-polymerase chain reaction (RT-PCR) was used in young leaves (from trees and in vitro shoots) and flower buds of almond (Prunus dulcis), a stone fruit, for cellular location of Prune dwarf virus (PDV, a member of the genus Ilarvirus). Sections obtained from samples fixed in formaldehyde and embedded in paraffin were refixed in formaldehyde to increase tissue preservation in the RT-PCR steps. The coat protein gene of PDV was used as the target to produce a cDNA copy that was amplified by PCR and visualized using a direct detection method with digoxigenin-labeled nucleotides. Protein digestion, PCR, and detection strategies were optimized for increased tissue preservation and signal intensity. PDV was found in infected samples within the vascular tissue of young leaves and flower buds as well as in the mesophyll in developing floral organs and in the generative and vegetative cells of pollen grains. PDV signals were observed in a ring surrounding the nucleus and spread in the cytoplasm. The results obtained are discussed in terms of the technique optimization and PDV distribution in tissues and transmission through pollen. The optimized protocol of in situ RT-PCR is a powerful technique to reveal low-abundant RNA species. Therefore, it is appropriate to study cell and subcellular distribution of RNA viruses in woody species.
- Development of a responsive fisheries management system for the Portuguese crustacean bottom trawl fishery: Lessons learntPublication . Silva, C.; Mendes, H.; Rangel, Mafalda; Wise, L.; Erzini, Karim; Borges, M. D.; Ballesteros, M.; Santiago, Jose Luis; Campos, Aida; Vioarsson, J.; Nielsen, K. NA prototype for a Responsive Fisheries Management System (RFMS) was developed in the context of the European FP7 project EcoFishMan and tested on the Portuguese crustacean trawl fishery. Building on Results Based Management principles, RFMS involves the definition of specific and measurable objectives for a fishery by the relevant authorities but allows resource users the freedom to find ways to achieve the objectives and to provide adequate documentation. Taking into account the main goals of the new Common Fisheries Policy, such as sustainable utilization of the resources, end of discards and unwanted catches, a management plan for the Portuguese crustacean trawl fishery was developed in cooperation with the fishing industry, following the process and design laid out in the RFMS concept. The plan considers biological, social and economic goals and assigns a responsibility for increased data collection to the resource users. The performance of the plan with regard to selected indicators was evaluated through simulations. In this paper the process towards a RFMS is described and the lessons learnt from the interaction with stakeholders in the development of an alternative management plan are discussed. (C) 2014 Elsevier Ltd. All rights reserved.
- Ecological quality assessment of transitional waters based on fish assemblages in Portuguese estuaries: The Estuarine Fish Assessment Index (EFAI)Publication . Cabral, H. N.; Fonseca, V. F.; Gamito, R.; Gonçalves, C. I.; Costa, J. L.; Erzini, Karim; Gonçalves, Jorge Manuel Santos; Martins, J.; Leite, L.; Andrade, José Pedro; Ramos, S.; Bordalo, A.; Amorim, E.; Neto, J. M.; Marques, J. C.; Rebelo, J. E.; Silva, C.; Castro, N.; Almeida, P. R.; Domingos, I.; Gordo, L. S.; Costa, M. JThe assessment of water quality has changed markedly worldwide over the last years, especially in Europe due to the implementation of the Water Framework Directive. Fish was considered a key-element in this context and several fish-based multi-metric indices have been proposed. In this study, we propose a multi-metric index, the Estuarine Fish Assessment Index (EFAI), developed for Portuguese estuaries, designed for the overall assessment of transitional waters, which could also be applied at the water body level within an estuary. The EFAI integrates seven metrics: species richness, percentage of marine migrants, number of species and abundance of estuarine resident species, number of species and abundance of piscivorous species, status of diadromous species, status of introduced species and status of disturbance sensitive species. Fish sampling surveys were conducted in 2006, 2009 and 2010, using beam trawl, in 13 estuarine systems along the Portuguese coast. Most of the metrics presented a high variability among the transitional systems surveyed. According to the EFAI values, Portuguese estuaries presented a "Good" water quality status (except the Douro in a particular year). The assessments in different years were generally concordant, with a few exceptions. The relationship between the EFAI and the Anthropogenic Pressure Index (API) was not significant, but a negative and significant correlation was registered between the EFAI and the expert judgement pressure index, at both estuary and water body level. The ordination analysis performed to evaluate similarities among North-East Atlantic Geographical Intercalibration Group (NEAGIG) fish-based indices put in evidence four main groups: the French index, since it is substantially different from all the other indices (uses only four metrics based on densities); indices from Ireland, United Kingdom and Spain (Asturias and Cantabria); the Dutch and German indices; and the indices of Belgium. Portugal and Spain (Basque country). The need for detailed studies, including comparative approaches, on several aspects of these assessment tools, especially in what regards their response to anthropogenic pressures was stressed. (C) 2011 Elsevier Ltd. All rights reserved.
- Ecological quality assessment of transitional waters based on fish assemblages in Portuguese estuaries: the Estuarine Fish Assessment Index (EFAI)Publication . Cabral, H. N.; Fonseca, V. F.; Gamito, R.; Gonçalves, C. I.; Costa, J. L.; Erzini, Karim; Gonçalves, J. M. S.; Martins, J.; Leite, L.; Andrade, José Pedro; Ramos, S.; Bordalo, A.; Amorim, E.; Neto, J. M.; Marques, J. C.; Rebelo, J. E.; Silva, C.; Castro, N.; Almeida, P. R.; Domingos, I.; Gordo, L. S.; Costa, M. J.The assessment of water quality has changed markedly worldwide over the last years, especially in Europe due to the implementation of the Water Framework Directive. Fish was considered a key-element in this context and several fish-based multi-metric indices have been proposed. In this study, we propose a multimetric index, the Estuarine Fish Assessment Index (EFAI), developed for Portuguese estuaries, designed for the overall assessment of transitional waters, which could also be applied at the water body level within an estuary. The EFAI integrates seven metrics: species richness, percentage of marine migrants, number of species and abundance of estuarine resident species, number of species and abundance of piscivorous species, status of diadromous species, status of introduced species and status of disturbance sensitive species. Fish sampling surveys were conducted in 2006, 2009 and 2010, using beam trawl, in 13 estuarine systems along the Portuguese coast. Most of the metrics presented a high variability among the transitional systems surveyed. According to the EFAI values, Portuguese estuaries presented a “Good” water quality status (except the Douro in a particular year). The assessments in different years were generally concordant, with a few exceptions. The relationship between the EFAI and the Anthropogenic Pressure Index (API) was not significant, but a negative and significant correlation was registered between the EFAI and the expert judgement pressure index, at both estuary and water body level. The ordination analysis performed to evaluate similarities among North-East Atlantic Geographical Intercalibration Group (NEAGIG) fish-based indices put in evidence four main groups: the French index, since it is substantially different from all the other indices (uses only four metrics based on densities); indices from Ireland, United Kingdom and Spain (Astúrias and Cantábria); the Dutch and German indices; and the indices of Belgium, Portugal and Spain (Basque country). The need for detailed studies, including comparative approaches, on several aspects of these assessment tools, especially in what regards their response to anthropogenic pressures was stressed.
- First representation of the trophic structure and functioning of the Portuguese continental shelf ecosystem: insights into the role of sardinePublication . Veiga-Malta, T.; Szalaj, D.; Angelico, M. M.; Azevedo, M.; Farias, I; Garrido, S.; Lourenco, S.; Marçalo, Ana; Marques, V; Moreno, A.; Oliveira, P. B.; Paiva, V. H.; Prista, N.; Silva, C.; Sobrinho-Goncalves, L.; Vingada, J.; Silva, A.In this study, we analysed the structure and functioning of the Portuguese continental shelf ecosystem and investigated the role of sardine Sardina pilchardus using the Ecopath massbalance approach. An Ecopath model was configured to represent the continental shelf waters in the period 2006-2009. The model showed that biomass was concentrated in low and intermediate trophic levels as in other upwelling areas. Several low- and medium-trophic-level groups were identified as dominant groups in the ecosystem (e.g. zooplankton, macrozoobenthos, sardine, chub mackerel Scomber colias, and demersal and benthopelagic invertivorous fish). Furthermore, lowtrophic-level groups were responsible for the main energy flows, and overall higher impact on the ecosystem, emphasizing the importance of bottom-up control of the ecosystem structure. Our results are relevant to understand structure and functioning of this ecosystem and constitute an important step towards an ecosystem approach to fisheries management in the study area.
- The influence of age, strength and stiffness on proprioception in knee osteoarthritisPublication . Espanha, M. M.; Pais, S.; Teles, J.; Silva, C.
- The influence of pain obesity and quadriceps strength on the gait of osteoarthritis patientsPublication . Pais, Sandra; Espanha, M.; Silva, C.Walking is a fundamental basic daily activity. Patients with osteoarthritis (OA) are known to have an altered walking pattern. Our goal was to contribute to the understanding of the influence of pain quadriceps strength and obesity on this gait pattern
- A WWW-based learning environment to complement a university course on neural networksPublication . Martins, L.; Silva, C.; Rodrigues, C.; Ruano, AntonioWeb Based Learning is increasingly attracting the interest of several teaching Institutions. It provides mechanisms for improving the conventional learning process, and also allows the opportunity for reaching new students, throughout the world, by just using an Internet connection. This paper describes a tool that is being built in the University of Algarve, to complement an optional course on Neural Networks. This tool incorporates multimedia material to explain visually important concepts, integrates Matlab, and will allow self-assessment and automatic student marking.