1,081 research outputs found

    Evaluation of ERBE scanner pointing accuracy based upon a coastline detection algorithm

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    Measurements from the Earth Radiation Budget Experiment (ERBE) scanning radiometers must be accurately located at the top of the Earth's atmosphere for proper interpretation of derived longwave and shortwave components of the Earth radiation field. The accuracy of the location calculations is affected by the orbit characteristics and attitude control systems of the three spacecraft, ERBS, NOAA-9, and NOAA-10. A technique was developed which makes use of the longwave scanner measurements to detect the thermal gradients at the boundaries of ocean and land masses. By analyzing many such coastline boundaries, estimates of the overall accuracy of the scanner measurement location calculations have been derived for the three satellites. The resulting measurement location errors are found to be smaller than the resolution of the radiometers, and this accuracy is well within the required location knowledge for useful science analysis of the ERBE scanner data

    In vivo clonal expansion and phenotypes of hypocretin-specific CD4(+) T cells in narcolepsy patients and controls

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    Individuals with narcolepsy suffer from abnormal sleep patterns due to loss of neurons that uniquely supply hypocretin (HCRT). Previous studies found associations of narcolepsy with the human leukocyte antigen (HLA)-DQ6 allele and T-cell receptor alpha (TRA) J24 gene segment and also suggested that in vitro-stimulated T cells can target HCRT. Here, we present evidence of in vivo expansion of DQ6-HCRT tetramer(+)/TRAJ24(+)/CD4(+) T cells in DQ6(+) individuals with and without narcolepsy. We identify related TRAJ24(+) TCRalphabeta clonotypes encoded by identical alpha/beta gene regions from two patients and two controls. TRAJ24-G allele(+) clonotypes only expand in the two patients, whereas a TRAJ24-C allele(+) clonotype expands in a control. A representative tetramer(+)/G-allele(+) TCR shows signaling reactivity to the epitope HCRT87-97. Clonally expanded G-allele(+) T cells exhibit an unconventional effector phenotype. Our analysis of in vivo expansion of HCRT-reactive TRAJ24(+) cells opens an avenue for further investigation of the autoimmune contribution to narcolepsy development

    Handling qualities of a wide-body transport airplane utilizing Pitch Active Control Systems (PACS) for relaxed static stability application

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    Piloted simulation studies have been conducted to evaluate the effectiveness of two pitch active control systems (PACS) on the flying qualities of a wide-body transport airplane when operating at negative static margins. These two pitch active control systems consisted of a simple 'near-term' PACS and a more complex 'advanced' PACS. Eight different flight conditions, representing the entire flight envelope, were evaluated with emphasis on the cruise flight conditions. These studies were made utilizing the Langley Visual/Motion Simulator (VMS) which has six degrees of freedom. The simulation tests indicated that (1) the flying qualities of the baseline aircraft (PACS off) for the cruise and other high-speed flight conditions were unacceptable at center-of-gravity positions aft of the neutral static stability point; (2) within the linear static stability flight envelope, the near-term PACS provided acceptable flying qualities for static stabilty margins to -3 percent; and (3) with the advanced PACS operative, the flying qualities were demonstrated to be good (satisfactory to very acceptable) for static stabilty margins to -20 percent

    Inactivating mutations and X-ray crystal structure of the tumor suppressor OPCML reveal cancer-associated functions

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    OPCML, a tumor suppressor gene, is frequently silenced epigenetically in ovarian and other cancers. Here we report, by analysis of databases of tumor sequences, the observation of OPCML somatic missense mutations from various tumor types and the impact of these mutations on OPCML function, by solving the X-ray crystal structure of this glycoprotein to 2.65 A resolution. OPCML consists of an extended arrangement of three immunoglobulin-like domains and homodimerizes via a network of contacts between membrane-distal domains. We report the generation of a panel of OPCML variants with representative clinical mutations and demonstrate clear phenotypic effects in vitro and in vivo including changes to anchorage-independent growth, interaction with activated cognate receptor tyrosine kinases, cellular migration, invasion in vitro and tumor growth in vivo. Our results suggest that clinically occurring somatic missense mutations in OPCML have the potential to contribute to tumorigenesis in a variety of cancers

    The BeppoSAX X-ray view of reflection-dominated Seyfert Galaxies

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    We present new results from BeppoSAX observations of reflection-dominated Seyfert galaxies, and namely: 1) the Compton-thick Seyfert 2s NGC1068 and Circinus Galaxy; 2) the Seyfert 1 NGC4051, whose nucleus was observed on May 1998 to have switched off, leaving only a residual reflection component as an echo of its past activity. Our main focus in this paper is on the soft X-ray continuum properties and on the X-ray line spectroscopy.Comment: 6 Latex pages, 5 figures, Accepted for publication in Advances in Space Research, Proceedings of 32nd Sci. Ass. of COSPA

    Efficiency of operation of interurban test-car

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    Thesis (B.S.)--University of Illinois, 1906.Typescript.Leaf 28 contains a folded chart

    Model for Cameron band emission in comets: A case for EPOXI mission target comet 103P/Hartley 2

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    The CO2 production rate has been derived in comets using the Cameron band (a3Pi - X1Sigma) emission of CO molecule assuming that photodissociative excitation of CO2 is the main production mechanism of CO in a3Pi metastable state. We have devoloped a model for the production and loss of CO(a3Pi) which has been applied to comet 103P/Hartley 2: the target of EPOXI mission. Our model calculations show that photoelectron impact excitation of CO and dissociative excitation of CO2 can together contribute about 60-90% to the Cameron band emission. The modeled brightness of (0-0) Cameron band emission on comet Hartley 2 is consistent with Hubble Space Telescope observations for 3-5% CO2 (depending on model input solar flux) and 0.5% CO relative to water, where photoelectron impact contribution is about 50-75%. We suggest that estimation of CO2 abundances on comets using Cameron band emission may be reconsidered. We predict the height integrated column brightness of Cameron band of ~1300 R during EPOXI mission encounter period.Comment: 3 figure

    The CASPiE Experience: Undergraduate Research in the 1st Year Chemistry Laboratory

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    With 40 separate programs represented amongst the students enrolled in 1st year chemistry at The University of Queensland (UQ), an integrative teaching and learning framework has evolved which incorporates inductive approaches to increase the relevance of chemistry in multidisciplinary contexts. With increasing evidence of poor engagement in the practical component of the course an intervention was planned through the introduction of an undergraduate research experience based on current innovative practice in chemical education (Weaver, Russell & Wink, 2008). The solar cell laboratory research module developed in the Centre for Authentic Practice in Science Education at Purdue University was translated to the UQ context. From a cohort of 1000 students, 26 students self-selected to participate in the pilot module which replaced three conventional ‘cook-book’ laboratory exercises. The adaptation of the module retained the skill-building and inquiry phases of the authentic CASPiE experience. Peer-assisted study sessions replaced the peer-led team learning component of the module and students were asked to prepare an abstract instead of a practical report to maintain the weighting in assessment compared to the majority of the course cohort. A mixed methods approach was adopted for the evaluation of the learning experience including pre- and post-tests, a ‘nature of science’ questionnaire and interviews. Data has been evaluated through quantitative and qualitative analysis (SPSS and NVivo). Students demonstrated increased engagement in the CASPiE module and greater gains in learning from this experience than in a conventional 1st year chemistry laboratory exercise. They exhibited greater engagement through the intellectual responsibility of completing their own experiments even when they failed to get the results they expected. The outcomes of this case study are presented including discussion of the implementation and factors that emerged reflecting the success of the translation of this pedagogical strategy from the US to Australian contexts. The outcomes of the pilot study are informing the scale-up of the implementation in 1st year chemistry and the development of a UQ research based module for implementation in 2nd level chemistry in 2009
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