196 research outputs found

    Laser driven launch vehicles for continuous access to space

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    The availability of megawatt laser systems in the next century will make laser launch systems from ground to orbit feasible and useful. Systems studies indicate launch capabilities of 1 ton payload per gigawatt laser power. Recent research in ground to orbit laser propulsion has emphasized laser supported detonation wave thrusters driven by repetitively pulsed infrared lasers. In this propulsion concept each laser repetition cycle consists of two pulses. A lower energy first pulse is used to vaporize a small amount of solid propellant and then after a brief expansion period, a second and higher energy laser pulse is used to drive a detonation wave through the expanded vapor. The results are reported of numerical studies comparing the detonation wave properties of various candidate propellants, and the simulation of thruster performance under realistic conditions. Experimental measurements designed to test the theoretical predictions are also presented. Measurements are discussed of radiance and opacity in absorption waves, and mass loss and momentum transfer. These data are interpreted in terms of specific impulse and energy conversion efficiency

    Marine algal (seaweed) flora of Terceira Island, Azores

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    BACKGROUND: As for many other Azorean Islands, the macroalgal flora of Terceira (belonging to the central group of the archipelago) is poorly known, the published information reflecting occasional collections of sporadic visitors to the island. In order to overcome this and contribute to improve the knowledge of Azorean macroalgal flora at both local and regional scales, a thorough investigation was conducted. Both collections and presence data recordings were undertaken at the littoral and sublittoral levels down to approximately 40 m around the island, covering a total area of approximately 49 km2. This paper lists the taxonomic records and provides information on each species’ ecology and occurrence on the Island’s littoral. NEW INFORMATION: A total of 418 specimens (including taxa identified only to genus level) belonging to 147 taxa of macroalgae, comprising 95 Rhodophyta, 33 Chlorophyta and 19 Ochrophyta (Phaeophyceae) are registered. Of these, 113 were identified to species level (73 Rhodophyta, 24 Chlorophyta and 16 Ochrophyta), encompassing 35 new records for the Island (27 Rhodophyta, 6 Chlorophyta and 2 Ochrophyta). Most species are native, including the Macaronesian endemisms Codium elisabethiae O.C.Schmidt, Millerella tinerfensis (Seoane-Camba) S.M.Boo & J.M.Rico and Phyllophora gelidioides P.Crouan & H.Crouan ex Karsakoff. Eight species are introduced and 15 have uncertain origin.This research was supported by the project “CAMAG/TER - Caracterização das massas de água costeira da Ilha Terceira”, funded by the Azores Regional Government and lately by the project “ACORES-01-0145-FEDER-000072” funded the Operational Programme Azores 2020 (85% ERDF and 15% regional funds). Afonso Prestes was supported by a PhD grant (M3.1.a/F/083/2015) awarded by Fundo Regional da Ciência e Tecnologia (FRCT).info:eu-repo/semantics/publishedVersio

    The Suitability for Organic Cattle Beef Production of Mixed Farming Systems in the Highlands of North East Portugal

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    The EC Reg. 1804/99 takes account of animal production in organic farming. However, these specifications may limit implementation and expansion of organic animal production, due to environmental and system constraints. Mixed farming, as defined by Spedding (1988) and Grigg (1996), is commonly practiced in the NE highlands of Portugal. Two farms were studied in this region in order to evaluate their suitability for organic cattle beef production, taking account of the technical specifications of the EC regulation

    Marine algal flora of Formigas Islets, Azores

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    BACKGROUND: The oldest reference to marine life in Formigas Islets (oriental group of the Azores archipelago) goes back to the 16th century. Nevertheless, their macroalgal flora is poorly known, the published information mainly resulting from occasional collections of sporadic visitors. To overcome this and contribute to the knowledge of Azorean macroalgal flora at both local and regional scales, a thorough investigation was conducted in 1990 and 1991 under two expeditions promoted by the Marine Biology Research Group of the Department of Biology, University of the Azores. Collections and presence data recordings were undertaken at the littoral and sublittoral levels down to approximately 40 m, in an area of approximately 0.04 km2. This paper lists the taxonomic records and provides information regarding each species’ ecology and occurrence on the Islets’ littoral. NEW INFORMATION: A total of 320 specimens are registered (including taxa identified only at generic level) belonging to 90 taxa of macroalgae, from which 70 were diagnosed at species level. The confirmed species comprise 39 Rhodophyta, 12 Chlorophyta and 19 Ochrophyta (Phaeophyceae), distributed in 22 orders (13 Rhodophyta, 3 Chlorophyta and 6 Ochrophyta) and 37 families (24 Rhodophyta, 6 Chlorophyta and 7 Ochrophyta). Sixty-one species represent new records for the Islets, from which Botryocladia macaronesica Afonso-Carrillo, Sobrino, Tittley & Neto and Laurencia viridis Gil-Rodriguez & Haroun are Macaronesian endemisms. Most species are native to the Azores, but six have an uncertain origin and four are introduced (the Rhodophyta Asparagopsis armata Harvey; Laurencia dendroidea J.Agardh; Neoizziella divaricata (C.K.Tseng) S.-M.Lin, S.-Y.Yang & Huisman and the Ochrophyta Hydroclathrus tilesii (Endlicher) Santiañez & M.J.Wynne).This research was mainly supported by the projects Expeditions “SANTA MARIA and FORMIGAS/90” and “FORMIGAS/91” and lately by the project “ACORES-01-0145-FEDER-000072” funded the Operational Programme Azores 2020 (85% ERDF and 15% regional funds). Afonso Prestes was supported by a PhD grant (M3.1.a/F/083/2015) awarded by Fundo Regional da Ciência e Tecnologia (FRCT).info:eu-repo/semantics/publishedVersio

    Marine algal flora of Pico Island, Azores

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    BACKGROUND: The seaweed flora of Pico Island (central group of the Azores archipelago) has attracted interest of researchers on past occasions. Despite this, the macroalgal flora of the island cannot be considered well-known as published information reflects only occasional collections. To overcome this, a thorough investigation encompassing collections and presence data recording was undertaken. Research under the Campaigns "AÇORES/89", "PICO/91", "PICOBEL/2007" and "LAUMACAT/2011" covered a relatively large area (approximately 39 km2) around the island, encompassing the littoral and sublittoral levels down to about 40 m around the Island.This paper improves the knowledge of the Azorean macroalgal flora at local and regional scales by listing taxonomic records and providing information on the ecology and occurrence of each species present on the Island's littoral. NEW INFORMATION: A total of 4043 specimens (including taxa identified only to genus level) belonging to 303 taxa of macroalgae are registered, comprising 197 Rhodophyta, 53 Chlorophyta and 53 Ochrophyta (Phaeophyceae). From these, 225 were identified to species level (142 Rhodophyta, 41 Chlorophyta and 42 Ochrophyta), encompassing 110 new records for the island (69 Rhodophyta, 20 Chlorophyta and 21 Ochrophyta), three Macaronesian endemisms (Botryocladia macaronesica Afonso-Carillo, Sobrino, Tittley & Neto; Laurencia viridis Gil-Rodríguez & Haroun; Codium elisabethiae O. C. Schmidt), 14 introduced and 25 species with an uncertain status.This research was supported by the project “PICOBEL: Coastal benthic communities of Pico Island: characterization and monitoring”, funded by the Azores Regional Government and lately by the project “ACORES-01-0145-FEDER-000072” funded the Operational Programme Azores 2020 (85% ERDF and 15% regional funds). Afonso Prestes was supported by a PhD grant (M3.1.a/F/083/2015) awarded by Fundo Regional da Ciência e Tecnologia (FRCT).info:eu-repo/semantics/publishedVersio

    Nitrous Oxide Enhances Na ϩ /Ca ϩϩ Exchange in the Neuroblastoma Cell Line SK-N-SH 1

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    ABSTRACT Changes in the concentration of cytosolic free calcium ([Ca ϩ

    Marine algal flora of Graciosa Island, Azores

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    BACKGROUND: The macroalgal flora of Graciosa (central group of Azores archipelago) is poorly known, with only 116 species recorded so far (authors personal data). The published information reflects occasional collections from sporadic field visits to the Island. To overcome this, a thorough investigation under the Expedition “GRACIOSA/2004”, the Campaigns “PADEL/2006”, “MACROBIOLMOL/2014” and “PIMA-BALA/2017” involving sample collecting and presence data recording, was undertaken over an area of 19 km2 encompassing littoral and sublittoral levels down to about 40 m around the Island. This paper lists the taxonomic records and provides information on species ecology and occurrence around the Island improving the knowledge of the Azorean macroalgal flora at both local and regional scales. NEW INFORMATION: A total of 1692 specimens belonging to 250 taxa of macroalgae (and including 55 taxa identified only at the genus level) are registered, comprising 166 Rhodophyta, 36 Chlorophyta and 48 Ochrophyta (Phaeophyceae). From these, 195 are identified to the species level (126 Rhodophyta, 31 Chlorophyta and 38 Ochrophyta) and comprise 156 native, 20 of uncertain origin and 14 introductions to the Island. Predaea feldmannii subsp. azorica Gabriel is an Azorean endemic, whereas Codium elisabethiae O.C. Schmidt, Botryocladia macaronesica Afonso-Carrillo, Sobrino, Tittley & Neto, Phyllophora gelidioides P.Crouan & H.Crouan ex Karsakoff and Laurencia viridis Gil-Rodríguez & Haroun represent Macaronesian endemics. Seventy-nine species are newly recorded to the algal flora of the Island.This research was supported by the projects “PADEL: Património natural e desenvolvimento sustentável do litoral dos Açores: a Ilha Graciosa como caso de estudo”, “MACROBIOMOL: Macroalgal biodiversity under molecular lens - towards a better understanding of North Atlantic biogeography”, “PIMA: Elaboração do programa de implementação da Diretiva-Quadro Estratégia Marinha - Programa invasoras marinhas nos Açores”, “BALA: Elaboração do programa de implementação da diretiva-quadro estratégia marinha - biodiversidade dos ambientes litorais dos Açores” and, most recently, by the project “ACORES-01-0145-FEDER-000072”, funded by the Operational Programme Azores 2020 (85% ERDF and 15% regional funds). Afonso Prestes was supported by a PhD grant (M3.1.a/F/083/2015) awarded by Fundo Regional da Ciência e Tecnologia (FRCT).info:eu-repo/semantics/publishedVersio

    The Prostate Care Questionnaire for Carers (PCQ-C): reliability, validity and acceptability

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    <p>Abstract</p> <p>Background</p> <p>Patient experience is commonly monitored in evaluating and improving health care, but the experience of carers (partners/relatives/friends) is rarely monitored even though the role of carers can often be substantial. For carers to fulfil their role it is necessary to address their needs. This paper describes an evaluation of the reliability, validity and acceptability of the PCQ-C, a newly developed instrument designed to measure the experiences of carers of men with prostate cancer.</p> <p>Methods</p> <p>The reliability, acceptability and validity of the PCQ-C were tested through a postal survey and interviews with carers. The PCQ-C was posted to 1087 prostate cancer patients and patients were asked to pass the questionnaire on to their carer. Non-responders received one reminder. To assess test-retest reliability, 210 carers who had responded to the questionnaire were resent it a second time three weeks later. A subsample of nine carers from patients attending one hospital took part in qualitative interviews to assess validity and acceptability of the PCQ-C. Acceptability to service providers was evaluated based on four hospitals' experiences of running a survey using the PCQ-C.</p> <p>Results</p> <p>Questionnaires were returned by 514 carers (47.3%), and the majority of questions showed less than 10% missing data. Across the sections of the questionnaire internal consistency was high (Cronbach's alpha ranging from 0.80 to 0.89), and test-retest stability showed moderate to high stability (intraclass correlation coefficients ranging from 0.52 to 0.83). Interviews of carers indicated that the PCQ-C was valid and acceptable. Feedback from hospitals indicated that they found the questionnaire useful, and highlighted important considerations for its future use as part of quality improvement initiatives.</p> <p>Conclusions</p> <p>The PCQ-C has been found to be acceptable to carers and service providers having been used successfully in hospitals in England. It is ready for use to measure the aspects of care that need to be addressed to improve the quality of prostate cancer care, and for research.</p
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