4,458 research outputs found

    Short term effects of irradiance on the growth of Pterocladiella capillacea (Gelidiales, Rhodophyta)

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    Pterocladiella capillacea has been economically exploited for agar extraction in the Azores for many years. Harvesting dropped to a full stop in the early 1990s due to a population collapse, but restarted in 2013. Since then it has been intensively harvested and overexploitation must be prevented, with both sustainable harvesting and effective cultivation practices. This study represents the first attempt to determine optimal conditions for P. capillacea production in the Azores, and evaluates its vegetative growth in two experiments using von Stosch’s medium designed to test entire thallus and tips portions response to different irradiances (30, 70 and 150 μmol photons m¯² s¯¹). The best relative growth rate (RGR) was recorded at 150 μmol photons m¯² s¯¹ for the entire thalli and tips after two-weeks and three-weeks, respectively, indicating that an acclimation period is necessary to assure the growth of this alga under experimental conditions. Higher RGR was obtained at higher irradiance (3.98 ± 2.10% fm day¯¹), but overall, growth rates were low or negative. Epiphytes were a serious problem towards the end of the entire thallus experiments, where Feldmannia irregularis proliferate at all irradiances. Future cultivation approaches complemented with other relevant environmental factors (e.g. pH, photoperiod, salinity), are recommended.FCT – Fundação para a Ciência e Tecnologia projects UID/BIA/00329/2013, 2015 - 2018 and UID/BIA/00329/2019, CIRN (Centro de Investigação de Recursos Naturais, University of the Azores), and CIIMAR (Interdisciplinary Centre of Marine and Environmental Research, Porto, Portugal). RFP was supported by a doctoral grant M3.1.2/F/024/2011, Fundo Regional para a Ciência e Tecnologia.info:eu-repo/semantics/publishedVersio

    Opportunities for Seaweed Aquaculture Development in the Azores

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    Jornadas "Ciência nos Açores – que futuro? Tema Ciências Naturais e Ambiente", Ponta Delgada, 7-8 de Junho de 2013.As macroalgas marinhas têm sido largamente usadas para diversos fins. Nos Açores, várias espécies têm sido usadas tradicionalmente na alimentação humana (e.g. Fucus spiralis, Porphyra spp., Laurencia spp. e Osmundea spp.) e para extracção de compostos com interesse na indústria dos ficocolóides (Pterocladiella capilacea e Gelidium spp.). As exigências no controlo da qualidade e as práticas actuais de colheita de macroalgas marinhas selvagens na Europa levantam preocupações ambientais sérias que tornam premente a necessidade se implementarem métodos de produção de biomassa controlados, como é o caso da aquacultura de macroalgas marinhas. Apesar da importância da exploração sustentável dos recursos marinhos existentes nos Açores, não existe informação sobre a viabilidade do cultivo de macroalgas marinhas no Arquipélago. O conhecimento sobre os requisitos básicos para o cultivo em grande escala das espécies nativas seleccionadas e os locais mais apropriados para a sua implementação está em falta. O objectivo principal do presente projecto é avaliar o potencial de cultivo de espécies de macroalgas marinhas seleccionadas, bem como identificar os métodos de cultivo mais adequados. Os resultados do programa de doutoramento serão de extrema importância quer em termos científicos quer em termos empresariais. Permitirão a transferência de tecnologia para o tecido empresarial regional e para a implementação de empresas de base tecnológica indo ao encontro das futuras políticas de financiamento europeias no âmbito do Programa Europeu Horizonte 2020.ABSTRACT: Seaweeds have a wide range of applications. In the Azores, several species of seaweeds were traditionally used either as food (e.g. Fucus spiralis, Porphyra spp., Laurencia spp. and Osmundea spp.) or for extraction of chemical products (Pterocladiella capilacea e Gelidium spp.). The product quality control requirements and concerns regarding the environmental sustainability of current wild seaweed biomass harvesting practices in Europe demand for controlled seaweed aquaculture. Despite the interest in exploiting Azorean seaweed resources, there is no information on the feasibility of cultivating seaweed in the Azores. Basic knowledge on large scale cultivation requirements of the selected native species is missing. The present project it’s aimed at evaluating the culture potential of selected Azorean species. The resulting outputs will be extremely important for both academic and economic purposes, bringing together the research and the market. Innovative enterprise will benefit from this project and develop technological breakthroughs into viable products with real commercial potential. This main objective is in according with the principal strategy of the Horizon 2020 that will tackle societal challenges after the end of FP7.Fundação para a Ciência e Tecnologi

    Understanding the Random Displacement Model: From Ground-State Properties to Localization

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    We give a detailed survey of results obtained in the most recent half decade which led to a deeper understanding of the random displacement model, a model of a random Schr\"odinger operator which describes the quantum mechanics of an electron in a structurally disordered medium. These results started by identifying configurations which characterize minimal energy, then led to Lifshitz tail bounds on the integrated density of states as well as a Wegner estimate near the spectral minimum, which ultimately resulted in a proof of spectral and dynamical localization at low energy for the multi-dimensional random displacement model.Comment: 31 pages, 7 figures, final version, to appear in Proceedings of "Spectral Days 2010", Santiago, Chile, September 20-24, 201

    A Catalog of Architectural Tactics for Cyber-Foraging

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    Mobile devices have become for many the preferred way of interacting with the Internet, social media and the enterprise. However, mobile devices still do not have the computing power or battery life that will allow them to perform effectively over long periods of time or for executing applications that require extensive communication or computation, or low latency. Cyber-foraging is a technique enabling mobile devices to extend their computing power and storage by offloading computation or data to more powerful servers located in the cloud or in single-hop proximity. This paper presents a catalog of architectural tactics for cyber-foraging that was derived from the results of a systematic literature review on architectures for cyber-foraging systems. Elements of the architectures identified in the primary studies were codified in the form of Architectural Tactics for Cyber-Foraging. These tactics will help architects extend their design reasoning towards cyber-foraging as a way to support the mobile applications of the present and the future

    Step-wise development of resilient ambient campus scenarios

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    This paper puts forward a new approach to developing resilient ambient applications. In its core is a novel rigorous development method supported by a formal theory that enables us to produce a well-structured step-wise design and to ensure disciplined integration of error recovery measures into the resulting implementation. The development method, called AgentB, uses the idea of modelling database to support a coherent development of and reasoning about several model views, including the variable, event, role, agent and protocol views. This helps system developers in separating various modelling concerns and makes it easier for future tool developers to design a toolset supporting this development. Fault tolerance is systematically introduced during the development of various model views. The approach is demonstrated through the development of several application scenarios within an ambient campus case study conducted at Newcastle University (UK) as part of the FP6 RODIN project. © 2009 Springer Berlin Heidelberg

    Model-based tool support for Tactical Data Links: an experience report from the defence domain

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    The Tactical Data Link (TDL) allows the exchange of information between cooperating platforms as part of an integrated command and control (C2) system. Information exchange is facilitated by adherence to a complex, message-based protocol defined by document-centric standards. In this paper, we report on a recent body of work investigating migration from a document-centric to a model-centric approach within the context of the TDL domain, motivated by a desire to achieve a positive return on investment. The model-centric approach makes use of the Epsilon technology stack and provides a significant improvement to both the level of abstraction and rigour of the network design. It is checkable by a machine and, by virtue of an MDA-like approach to the separation of domains and model transformation between domains, is open to integration with other models to support more complex workflows, such as by providing the results of interoperability analyses in human-readable domain-specific reports conforming to an accepted standard

    A Process Framework for Designing Software Reference Architectures for Providing Tools as a Service

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    Product-Focused Software Process ImprovementSoftware Reference Architecture (SRA), which is a generic architecture solution for a specific type of software systems, provides foundation for the design of concrete architectures in terms of architecture design guidelines and architecture elements. The complexity and size of certain types of software systems need customized and systematic SRA design and evaluation methods. In this paper, we present a software Reference Architecture Design process Framework (RADeF) that can be used for analysis, design and evaluation of the SRA for provisioning of Tools as a Service as part of a cloud-enabled workSPACE (TSPACE). The framework is based on the state of the art results from literature and our experiences with designing software architectures for cloud-based systems. We have applied RADeF SRA design two types of TSPACE: software architecting TSPACE and software implementation TSPACE. The presented framework emphasizes on keeping the conceptual meta-model of the domain under investigation at the core of SRA design strategy and use it as a guiding tool for design, evaluation, implementation and evolution of the SRA. The framework also emphasizes to consider the nature of the tools to be provisioned and underlying cloud platforms to be used while designing SRA. The framework recommends adoption of the multi-faceted approach for evaluation of SRA and quantifiable measurement scheme to evaluate quality of the SRA. We foresee that RADeF can facilitate software architects and researchers during design, application and evaluation of a SRA and its instantiations into concrete software systems.Muhammad Aufeef Chauhan, Muhammad Ali Babar, and Christian W. Probs

    Growth responses of Macrocystis pyrifera (Laminariales), Southern Chile, juvenile sporophytes to nutrient limitation

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    1st Mares Conference on Marine Ecosystems Health and Conservation. Olhão, Portugal 17-21 November 2014.Kelp forests represent some of the most conspicuous coastal habitats and today we recognize only one giant kelp species (Macrocystis pyrifera) distributed globally [1, 2]. M. pyrifera is recognized as a perennial kelp species with a low capacity of energy storage, whereas its high productivity is associated the availability of nitrogen from the water column [3]. The relation between M. pyrifera growth and biomass production results from a plastic response of the sporophytes to temporal and spatial variability in nitrogen availability [4, 5]. However, the low storage capacity of giant kelp [6, 7] is clearly disadvantageous during periods of suboptimal environmental conditions; as those that occur seasonally in California and the inland waters of southern Chile. Due to an increased demand for kelp biomass in Chile for the world alginate industry and abalone farming in Chile [8, 9] there is an increased demand of raw material and interest for developing kelp aquaculture technologies [10]. The present study evaluates the effect of different nitrogen availability on the growth and regeneration of juvenile fronds of M. pyrifera sporophytes from southern Chile and explore its consequences for the development of seeding strategies of kelp farming in southern Chile

    Measurement of the W-pair Production Cross-section and W Branching Ratios at s\sqrt{s}=205 and 207 GeV

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    The cross-section for the process e+e-->W+W- was measured with the data sample collected by DELPHI at centre-of-mass energies up to 209 GeV and corresponding to a total integrated luminosity of about 209 pb^-1. The branching ratios of the W decay were also measured; from them the value of |Vcs| was extracted. The results are compared with the most recent calculations in the frame of the Standard Model
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