928 resultados para Power Reactor Development Co.
CO Oxidation and the CO/NO Reaction on Pd(110) Studied Using "Fast" XPS and a Molecular Beam Reactor
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The Organisation for Economic Co-operation and Development (OECD) Terrestrial plant test is often used for the ecological risk assessment of contaminated land. However, its origins in plant protection product testing mean that the species recommended in the OECD guidelines are unlikely to occur on contaminated land. Six alternative species were tested on contaminated soils from a former Zn smelter and a metal fragmentizer with elevated concentrations of Cd, Cu, Pb, and Zn. The response of the alternative species was compared to two species recommended by the OECD; Lolium perenne (perennial ryegrass) and Trifolium pratense (red clover). Urtica dioica (stinging nettle) and Poa annua (annual meadow-grass) had low emergence rates in the control soil so may be considered unsuitable. Festuca rubra (chewings fescue), Holcus lanatus (Yorkshire fog), Senecio vulgaris (common groundsel), and Verbascum thapsus (great mullein) offer good alternatives to the OECD species. In particular, H. lanatus and S. vulgaris were more sensitive to the soils with moderate concentrations of Cd, Cu, Pb, and Zn than the OECD species.
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We reported previously that bone morphogenetic proteins (BMPs) potently suppress CYP17 expression and androgen production by bovine theca interna cells (TC) in vitro. In this study, real-time PCR was used to analyse gene expression in TC and granulosa cell (GC) layers from developing bovine antral follicles (1-18 mm). Abundance of mRNA transcripts for four BMPs (BMP2, BMP4, BMP6, and BMP7) and associated type I (BMPR1A, BMPR1B, ACVR1 and ACVR1B) and type II (BMPR2, ACVR2A and ACVR2B) receptors showed relatively modest, though significant, changes during follicle development. BMP2 was selectively expressed in GC, while BMP6, BMP7 and betaglycan (TGFBR3) were more abundant in TC. Abundance of betaglycan mRNA (inhibin co-receptor) in TC increased progressively (fivefold; P<0.001) as follicles grew from 1-2 to 9-10 mm. This suggests a shift in thecal responsiveness to GC-derived inhibin, produced in increasing amounts as follicles achieve dominance. This prompted us to investigate whether inhibin can function as a physiological antagonist of BMP action on bovine TC in vitro, in a manner comparable to that for activin signalling. BMP4, BMP6 and BMP7 abolished LH-induced androstenedione secretion and suppressed CYP17 mRNA >200-fold (P<0.001), while co-treatment with inhibin-A reversed the suppressive action of BMP in each case (P<0.001). Results support a physiological role for granulosa-derived inhibin as an antagonist of BMP action on thecal androgen synthesis. A shift in intrafollicular balance between thecal BMP signalling (inhibitory for androgen synthesis) and betaglycan-dependent inhibin signalling (stimulatory for androgen synthesis) accords with the physiological requirement to deliver an adequate supply of aromatase substrate to GC of developing follicles.
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Current approaches for the reduction of carbon emissions in buildings are often predicated on the integration of renewable technologies into building projects. Building integrated photovoltaics (BIPV) is one of these technologies and brings its own set of challenges and problems with a resulting mutual articulation of this technology and the building. A Social Construction of Technology (SCOT) approach explores how negotiations between informal groups of project actors with shared interests shape the ongoing specification of both BIPV and the building. Six main groups with different interests were found to be involved in the introduction of BIPV (Cost Watchers, Design Aesthetes, Green Guardians, Design Optimizers, Generation Maximizers and Users). Their involvement around three sets of issues (design changes from lack of familiarity with the technology, misunderstandings from unfamiliar interdependencies of trades and the effects of standard firm procedure) is followed. Findings underline how BIPV requires a level of integration that typically spans different work packages and how standard contractual structures inhibit the smooth incorporation of BIPV. Successful implementation is marked by ongoing (re-)design of both the building and the technology as informal fluid groups of project actors with shared interests address the succession of problems which arise in the process of implementation.
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The growth of mining activities in Africa in the last decade has coincided with increased attention on the fate of the continent’s forests, specifically in the contexts of livelihoods and climate change. Although mining has serious environmental impacts, scant attention has been paid to the processes which shape decision-making in contexts where minerals and forests overlap. Focussing on the illustrative case of Ghana, this paper articulates the dynamics of power, authority and legitimacy of private companies, traditional authorities and key state institutions in governing mining activities in forests. The analysis highlights how mining companies and donors promote a neoliberal model of resource management which entrenches their ability to benefit from mineral exploitation and marginalises the role of state institutions and traditional authorities in decision-making. This subsequently erodes state authority and legitimacy and compounds the contested nature of traditional authorities’ legitimacy. A more nuanced examination of foundational governance questions concerning the relative role of the state, traditional authorities and private interests is needed.
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This paper describes a new mechanical samples positioning system that allows the safe placement and removal of biological samples for prolonged irradiation, in a nuclear reactor during full-power continuous operation. Also presented herein the materials of construction and operating principles. Additionally, this sample positioning system is compared with an existing pneumatic and automated transfer system, already available at the research reactors. The system consists of a mechanical arm with a claw, which can deliver the samples for irradiations without reactor shutdown. It was installed in the lEA-R1 research reactor at Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, Brazil, and for the past 5 years, the system has successfully operated and allowed the conducting of important experiments. As a result of its introduction, the facility has been in a position to positively respond to the increased demand in studies of biology, medicine, physics, engineering, detector/dosimeter calibrations, etc. It is one example of the appropriated technologies that save energy and resources. (C) 2010 Elsevier Ltd. All rights reserved.
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The conventional Newton's method has been considered inadequate to obtain the maximum loading point (MLP) of power systems. It is due to the Jacobian matrix singularity at this point. However, the MLP can be efficiently computed through parameterization techniques of continuation methods. This paper presents and tests new parameterization schemes, namely the total power losses (real and reactive), the power at the slack bus (real or reactive), the reactive power at generation buses, the reactive power at shunts (capacitor or reactor), the transmission lines power losses (real and reactive), and transmission lines power (real and reactive). Besides their clear physical meaning, which makes easier the development and application of continuation methods for power systems analysis, the main advantage of some of the proposed parameters is that its not necessary to change the parameter in the vicinity of the MLP. Studies on the new parameterization schemes performed on the IEEE 118 buses system show that the ill-conditioning problems at and near the MLP are eliminated. So, the characteristics of the conventional Newton's method are not only preserved but also improved. (C) 2003 Elsevier B.V. B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Includes bibliography
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Discurso pronunciado por el Director para las Relaciones con América Latina, en representación de la Comisión de las Comunidades Europeas, el 11 de mayo.
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Includes bibliography