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Science and, Ireland

Adjei-Boateng D.,Kwame Nkrumah University Of Science And Technology | Wilson J.G.,TCD
Estuarine, Coastal and Shelf Science | Year: 2013

The reproductive cycle of Galatea paradoxa which is the basis for an artisanal fishery in the Volta River estuary, Ghana, was studied using condition indices and histological methods from March 2008 to July 2009. The cycle is annual with a single spawning event between June and October. Gametogenesis starts in November progressing steadily to a peak in June-July when spawning begins until October when the animal is spent. The condition indices (shell-free wet weight/total wet weight, ash-free dry weight/shell weight and gonad wet weight/shell weight) showed a clear relationship with the gametogenic stage rising from a minimum at stage (I) start of gametogenesis, to their highest values at stages (IIIA) ripe and (IIIB) start of spawning before declining significantly to stage (IV) spent.It is suggested that condition index may prove a valuable technique in fishery management to recognise the reproductive stages of G.paradoxa as it is less expensive and time consuming than histological techniques in addition to being easier to teach to non-specialists. The data presented in this study provide information on the timing of spawning events for G.paradoxa, which is necessary for developing sustainable management strategies and selection of broodstock for aquaculture. © 2011 Elsevier Ltd. Source


Ruffini M.,TCD | Wosinska L.,Heading the Optical Networks Laboratory | Achouche M.,Opto Electronic Integrated Circuits OEIC | Chen J.,Optical Networks Laboratory at KTH | And 7 more authors.
IEEE Communications Magazine | Year: 2014

Fiber to the premises has promised to increase the capacity in telecommunications access networks for well over 30 years. While it is widely recognized that optical-fiber-based access networks will be a necessity in the shortto medium-term future, its large upfront cost and regulatory issues are pushing many operators to further postpone its deployment, while installing intermediate unambitious solutions such as fiber to the cabinet. Such high investment cost of both network access and core capacity upgrade often derives from poor planning strategies that do not consider the necessity to adequately modify the network architecture to fully exploit the cost benefit that a fiber-centric solution can bring. DISCUS is a European Framework 7 Integrated Project that, building on optical-centric solutions such as long-reach passive optical access and flat optical core, aims to deliver a cost-effective architecture for ubiquitous broadband services. DISCUS analyzes, designs, and demonstrates end-to-end architectures and technologies capable of saving cost and energy by reducing the number of electronic terminations in the network and sharing the deployment costs among a larger number of users compared to current fiber access systems. This article describes the network architecture and the supporting technologies behind DISCUS, giving an overview of the concepts and methodologies that will be used to deliver our end-to-end network solution. © 2013 IEEE. Source


Brennan R.,Trinity College Dublin | Feeney K.,Trinity College Dublin | Song Y.,KDEG | O'Sullivan D.,TCD
IEEE Communications Magazine | Year: 2013

Federated services are commonplace. Federated monitoring suffers from the classic development lag of being seen as a non-functional requirement. This has led to the development of monitoring federation techniques that focus on federation as a technical integration point rather than a dynamic business-to-business mediation function. This article presents a novel decentralized secure approach to creating and managing heterogeneous monitoring federations. This new approach relies on explicit management of the federal relationships rather than just the shared or exported services. Federal relationship management is achieved through the creation of trusted communication paths between federation members and the maintenance of semantic capability models for the shared monitoring services or resources. Monitoring capability heterogeneity and interoperability are addressed through the deployment of a managed semantic interoperability process between federated domains. Finally, a monitoring data annotation service, called semantic uplift, is used to ensure that sufficient context is provided with monitoring data to support its consumption by non-expert users in other domains. This novel approach gives the flexibility to deal with the dynamism and diversity of realistic multi-domain monitoring deployments. © 2013 IEEE. Source


Wilson J.G.,TCD | Galaktionov K.V.,Zoological Institute | Sukhotin A.A.,Zoological Institute | Skirnisson K.,University of Iceland | And 5 more authors.
Estuarine, Coastal and Shelf Science | Year: 2013

The level and incidence of infection of blue mussels (Mytilus spp) by the trematode parasites Himasthla, Renicola and Gymnophallus were studied at 22 sites from north Atlantic waters (Ireland, Iceland, Norway) and across the Arctic Ocean to the Sea of Ohktosk in the north Pacific. Only at one site (Pechora Sea) were no parasites at all recorded. Infestation levels ranged up to 100% of individuals sampled.Data were analysed with the PRIMER-E package BEST routine. The analysis indicated a considerable influence of geographic location, with closely-connected sites also grouped together on the basis of their parasite communities. The BEST routine suggested that the major influence on infestation was bird (final host) numbers, but that exposure was also a strong factor. The implications of these findings in relation to human exploitation of mussels, to bird conservation, and to the provision of ecosystem goods and services in general is discussed. © 2011 Elsevier Ltd. Source


Adjei-Boateng D.,Kwame Nkrumah University Of Science And Technology | Wilson J.G.,TCD
Knowledge and Management of Aquatic Ecosystems | Year: 2012

Population parameters such as asymptotic (L∞), growth coefficient (K), mortality rates (Z, F and M), exploitation level (E) and recruitment pattern of the freshwater clam Galatea paradoxa were estimated using lengthfrequency data from the Volta River estuary, Ghana. The L ∞ for G. paradoxa at the Volta estuary was 105.7 mm, the growth coefficient (K) and the growth performance index (Ǿ) ranged between 0.14-0.18 year-1 and 3.108-3.192, respectively. Total mortality (Z) was 0.65-0.82 year-1, while natural mortality (M) and fishing mortality (F) were 0.35-0.44 year-1 and 0.21-0.47 year-1, respectively, with an exploitation level of 0.32-0.57. The recruitment pattern suggested that G. paradoxa has year-round recruitment with a single pulse over an extended period (October-March) in the Volta River. The Volta River stock of G. paradoxa is overfished and requires immediate action to conserve it. This can be achieved by implementing a minimum landing size restriction and intensifying the culture of smaller clams which is a traditional activity at the estuary. © 2012 ONEMA. Source

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