342 research outputs found

    Point-Focus Concentration Compact Telescoping Array: EESP Option 1 Phase Final Report for Public Release

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    Orbital ATK, in partnership with Mark ONeill LLC (MOLLC) and SolAero Technologies Corp., has developed a novel solar array platform, PFC-CTA, which provides a significant advance in performance and cost reduction compared to all currently available space solar systems. PFC refers to the Point Focus Concentration of light provided by MOLLCs thin, flat Fresnel optics. These lenses focus light to a point of approximately 100 times the intensity of the ambient light, onto a solar cell of approximately 1/25th the size of the lens. CTA stands for Compact Telescoping Array1, which is the solar array blanket structural platform originally devised by NASA and currently being advanced by Orbital ATK and partners under NASA and AFRL funding to a projected TRL 5+ by late-2018. The NASA Game Changing Development Extreme Environment Solar Power (EESP) Option 1 Phase study has enabled Orbital ATK to generate and refine component designs, perform component level and system performance analyses, and test prototype hardware of the key elements of PFC-CTA, and increased the TRL of PFC-specific technology elements to TRL ~5. Key performance metrics currently projected are as follows: Scalability from 300 kW per wing (AM0); Specific Power > 250 W/kg (BoL, AM0); Stowage Efficiency > 60 kW/m3; 5:1 margin on pointing tolerance vs. capability; >50% launched cost savings; Wide range of operability between Venus and Saturn by active and/or passive thermal management

    EXPANDINDO HORIZONTES NA HISTÓRIA DO ESPORTE: FILMES, FOTOGRAFIAS E MONUMENTOS

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    Resumo: Historiadores do esporte, em geral, seguem práticas de trabalho historiográfico padronizadas ao buscarem narrar o passado no presente, focando seus interesses em material escrito. Esse artigo argumenta que, por mais importantes que as fontes escritas sejam para o trabalho do historiador, a história do esporte teria a ganhar se considerasse representações do passado que incluam cultura visual e material. Mais especificamente, este trabalho investiga filmes, fotografias e monumentos, e tenta responder duas questões-chave. Como os historiadores do esporte têm se relacionado com estas formas de cultura visual e material? Em segundo lugar, como poderiam os historiadores do esporte, baseado em práticas desenvolvidas em outros campos, ampliar o uso de filmes, fotografias e monumentos em seu trabalho? Argumentamos que os historiadores do esporte estão em uma posição que permite articular as complexas relações entre o passado esportivo e o presente usando diferentes formas de cultura visual e material.Palavras-Chave: filme, fotografia, metodologia, monumento BROADENING HORIZONS IN SPORT HISTORY: FILMS, PHOTOGRAPHS, AND MONUMENTSAbstract: Sport historians, in the main, follow standard historical practice by focusing their interests on written material in their quests to relate the past in the present. This paper argues that as important as written sources are to the historical process, sport history could benefit by considering representations of the past that include visual and material culture. More specifically, this paper investigates film, photographs, and monuments and attempts to answer two key questions. How have sport historians related to these forms of visual and material culture? Secondly, how could sport historians, based on the practices developed in other fields, extend the use of films, photographs, and monuments in their work? We contend that sport historians are in a position to articulate the complex relationships between the sporting past in the present by embracing different forms of visual and material culture.Keywords: film, fotografia, methodology, monument

    Interaction between a galactic disk and a live dark halo with an anisotropic velocity distribution

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    We have extended previous analytical studies of the interaction of dark halos with galactic disks by introducing for the halo particles anisotropic distribution functions in phase space. For this purpose we have employed the shearing sheet model of a patch of a galactic disk embedded in a homogeneous halo. We find that velocity anisotropy increases considerably the maximum growth factor of perturbations in the disk.Comment: 5 pages, 1 figure, accepted by Astronomy & Astrophysic

    Subgroup characteristics of marine methane-oxidizing ANME-2 archaea and their syntrophic partners revealed by integrated multimodal analytical microscopy

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    Phylogenetically diverse environmental ANME archaea and sulfate-reducing bacteria cooperatively catalyze the anaerobic oxidation of methane oxidation (AOM) in multicelled consortia within methane seep environments. To better understand these cells and their symbiotic associations, we applied a suite of electron microscopy approaches, including correlative fluorescence in situ hybridization-electron microscopy (FISH-EM), transmission electron microscopy (TEM), and serial block face scanning electron microscopy (SBEM) three-dimensional (3D) reconstructions. FISH-EM of methane seep-derived consortia revealed phylogenetic variability in terms of cell morphology, ultrastructure, and storage granules. Representatives of the ANME-2b clade, but not other ANME-2 groups, contained polyphosphate-like granules, while some bacteria associated with ANME-2a/2c contained two distinct phases of iron mineral chains resembling magnetosomes. 3D segmentation of two ANME-2 consortium types revealed cellular volumes of ANME and their symbiotic partners that were larger than previous estimates based on light microscopy. Polyphosphate-like granule-containing ANME (tentatively termed ANME-2b) were larger than both ANME with no granules and partner bacteria. This cell type was observed with up to 4 granules per cell, and the volume of the cell was larger in proportion to the number of granules inside it, but the percentage of the cell occupied by these granules did not vary with granule number. These results illuminate distinctions between ANME-2 archaeal lineages and partnering bacterial populations that are apparently unified in their ability to perform anaerobic methane oxidation

    Surface flattening of the human left atrium and proof-of-concept clinical applications

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    Surface flattening in medical imaging has seen widespread use in neurology and more recently in cardiology to describe the left ventricle using the bull's-eye plot. The method is particularly useful to standardize the display of functional information derived from medical imaging and catheter-based measurements. We hypothesized that a similar approach could be possible for the more complex shape of the left atrium (LA) and that the surface flattening could be useful for the management of patients with atrial fibrillation (AF). We implemented an existing surface mesh parameterization approach to flatten and unfold 3D LA models. Mapping errors going from 2D to 3D and the inverse were investigated both qualitatively and quantitatively using synthetic data of regular shapes and computer tomography scans of an anthropomorphic phantom. Testing of the approach was carried out using data from 14 patients undergoing ablation treatment for AF. 3D LA meshes were obtained from magnetic resonance imaging and electroanatomical mapping systems. These were unfolded using the developed approach and used to demonstrate proof-of-concept applications, such as the display of scar information, electrical information and catheter position. The work carried out shows that the unfolding of complex cardiac structures, such as the LA, is feasible and has several potential clinical uses for the management of patients with AF.</p

    The Sigma Class glutathione transferase from the liver fluke Fasciola hepatica

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    BACKGROUND: Liver fluke infection of livestock causes economic losses of over US$ 3 billion worldwide per annum. The disease is increasing in livestock worldwide and is a re-emerging human disease. There are currently no commercial vaccines, and only one drug with significant efficacy against adult worms and juveniles. A liver fluke vaccine is deemed essential as short-lived chemotherapy, which is prone to resistance, is an unsustainable option in both developed and developing countries. Protein superfamilies have provided a number of leading liver fluke vaccine candidates. A new form of glutathione transferase (GST) family, Sigma class GST, closely related to a leading Schistosome vaccine candidate (Sm28), has previously been revealed by proteomics in the liver fluke but not functionally characterised. METHODOLOGY/PRINCIPAL FINDINGS: In this manuscript we show that a purified recombinant form of the F. hepatica Sigma class GST possesses prostaglandin synthase activity and influences activity of host immune cells. Immunocytochemistry and western blotting have shown the protein is present near the surface of the fluke and expressed in eggs and newly excysted juveniles, and present in the excretory/secretory fraction of adults. We have assessed the potential to use F. hepatica Sigma class GST as a vaccine in a goat-based vaccine trial. No significant reduction of worm burden was found but we show significant reduction in the pathology normally associated with liver fluke infection. CONCLUSIONS/SIGNIFICANCE: We have shown that F. hepatica Sigma class GST has likely multi-functional roles in the host-parasite interaction from general detoxification and bile acid sequestration to PGD synthase activity
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