1,692 research outputs found

    On the Sensitivity of Massive Star Nucleosynthesis and Evolution to Solar Abundances and to Uncertainties in Helium Burning Reaction Rates

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    We explore the dependence of pre-supernova evolution and supernova nucleosynthesis yields on the uncertainties in helium burning reaction rates. Using the revised solar abundances of Lodders (2003) for the initial stellar composition, instead of those of Anders & Grevesse (1989), changes the supernova yields and limits the constraints that those yields place on the 12C(a,g)16O reaction rate. The production factors of medium-weight elements (A = 16-40) were found to be in reasonable agreement with observed solar ratios within the current experimental uncertainties in the triple alpha reaction rate. Simultaneous variations by the same amount in both reaction rates or in either of them separately, however, can induce significant changes in the central 12C abundance at core carbon ignition and in the mass of the supernova remnant. It therefore remains important to have experimental determinations of the helium burning rates so that their ratio and absolute values are known with an accuracy of 10% or better.Comment: Accepted for publication by the Astrophysical Journa

    Analysis of Participation in Multifunctional Agriculture: U.S. Rice Farms

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    Multifunctional agriculture is particularly fundamental to some working lands conservation policies and programs, such as the Environmental Quality Incentive Program (EQIP), Conservation Security Program (CSP) and Wildlife Habitat Incentive Program (WHIP). Farmers can also be engaged in providing recreational and agri-tourism services such as hunting, fishing, bird-watching, farm tours, petting zoos and hospitality services. Using the Agricultural Resource Management Survey (ARMS) we analyze factors associated with participation in conservation, recreation and agri-tourism activities as a function of farm structure, farm financial measures, production practices, and socio-demographic characteristics of the farm operator. To estimate the functional relationships we estimate a binary logistic model where the dependent variable takes a value equal to one if the farm operator reports in the ARMS survey participation in conservation programs, recreation or agritourism. Results show that the level of farm operator education and cultural practices that use conservation technical assistance are significant at the 0.01 and 0.10 levels, respectively, in explaining participation. Farm financial characteristics were not significant. Location (state where operator is located) is also not significant.multifunctional agriculture, agri-environmental policy, rice, logistic model, Agricultural and Food Policy, Land Economics/Use, Q18, Q26, Q28,

    Analysis of Participation in Multifunctional Agriculture: U.S. Rice Farms

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    Multifunctional agriculture is particularly fundamental to some working lands conservation policies and programs, such as the Environmental Quality Incentive Program (EQIP), Conservation Security Program (CSP) and Wildlife Habitat Incentive Program (WHIP). Farmers can also be engaged in providing recreational and agri-tourism services such as hunting, fishing, bird-watching, farm tours, petting zoos and hospitality services. Using the Agricultural Resource Management Survey (ARMS) we analyze factors associated with participation in conservation, recreation and agri-tourism activities as a function of farm structure, farm financial measures, production practices, and socio-demographic characteristics of the farm operator. To estimate the functional relationships we estimate a binary logistic model where the dependent variable takes a value equal to one if the farm operator reports in the ARMS survey participation in conservation programs, recreation or agritourism. Results show that the level of farm operator education and cultural practices that use conservation technical assistance are significant at the 0.01 and 0.10 levels, respectively, in explaining participation. Farm financial characteristics were not significant. Location (state where operator is located) is also not significant.multifunctional agriculture, agri-environmental policy, rice, logistic model, Agricultural and Food Policy, Community/Rural/Urban Development, Crop Production/Industries, Environmental Economics and Policy, Land Economics/Use, Q18, Q26, Q28,

    The development of the reflective practitioner through digital storytelling

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    This paper presents a multiple case study on the use of digital storytelling to support the development of reflection and digital skills in professional education. Students from two universities, one group studying health and social care, the other training to be teachers, were asked to produce two artefacts, at the beginning and end of their respective modules, in which they reflected on the aspects of professional and personal learning. The artefacts, some of which were produced in groups, others by individual students, were analysed for recurring themes, levels of reflection and digital competence, particularly in the use of open educational resources. Findings from the analysis support the use of digital storytelling methods to develop a range of key skills pertinent to professional education in general but concluded that the deeper levels of reflection may be most evident in individual artefacts produced in the later stages of professional education. The study provides some important insights for teaching and learning in professional education as it suggests that digital storytelling provides a highly engaging way of introducing both reflective and open educational practices

    Sertaconazole antifungal profile determined by a microdilution method versus nine topical substances against dermatophyte fungi

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    Antifungal activity and in vitro inhibition time for sertaconazole (STZ) and 9 other topical drugs, namely amorolfine, bifonazole, clotrimazole, econazole, ketoconazole, miconazole, oxiconazole, terbinafine, and tioconazole were determined against 124 clinical isolates of dermatophyte (12 species) fungi by the microdilution method in a liquid medium and the measurement of optical density. STZ's antifungal activity was not always affected by the tested dermatophyte genus, as was the case with the remaining antifungals. In vitro antifungal activity was at the same level for all the studied azole derivatives, but, in terms of partial inhibitory concentrations, STZ starts its in vitro inhibitory activity in a shorter time than the other tested substances, particularly in those incubation periods when the growth of the dermatophyte fungi was more developed.Fil: Carrillo Muñoz, A. J.. No especifíca;Fil: Tur Tur, C.. No especifíca;Fil: Cárdenes, D.. No especifíca;Fil: Rojas, Florencia Dinorah. Universidad Nacional del Nordeste. Instituto de Medicina Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Giusiano, Gustavo Emilio. Universidad Nacional del Nordeste. Instituto de Medicina Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentin

    Els cnidaris bentònics

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    En aquest treball es presenten 85 espècies de cnidaris bentònics trobats als fons que envolten l'Arxipèlag de Cabrera. També es fa esment de la distribució bionòmica de les espècies més representatives i es compara la fauna trobada amb la de la immediata costa de Mallorca, la costa catalana, i, en general, les del litoral de la Mediterrània central i occidental.A check-list of the benthic Cnidaria inhabiting the Archipelago of Cabrera is presented, with comments on the bionomic distribution of the most representative species. The faunistic composition and the species distribution is very similar to the other Balearic islands and the species pool is representative of the coastal Mediterranean Cnidarian fauna
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