323 research outputs found

    A statistical study of the magnetic signatures of FTEs near the dayside magnetopause

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    During magnetopause crossings, the AMPTE CCE satellite frequently observed flux transfer events (FTEs) characterized by fluctuations in the magnetic field strength (B) and bipolar signatures in the field component (BN) normal to the nominal magnetopause. In this study, we survey 110 events observed from October to December 1984 and during January 1986. Nearly all events exhibited increases in B, and although the majority of events exhibited a symmetric bipolar signature in BN, a significant number (31 of 110) had asymmetric bipolar signatures in which the trailing pulse was dominant. Most of the asymmetric events were observed near the magnetic equator. This is consistent with an explanation in which FTEs form via merging along a single subsolar X line with strongly asymmetric signatures but that these signatures evolve into the familiar symmetric bipolar form with distance from the merging line

    HgCdTe Avalanche Photodiode Array Detectors with Single Photon Sensitivity and Integrated Detector Cooler Assemblies for Space Lidar Applications

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    A HgCdTe avalanche photodiode (APD) focal plane array assembly with linear mode photon-counting capability has been developed for space lidar applications. An integrated detector cooler assembly (IDCA) has been built using a miniature Stirling cooler. A microlens array has been included to improve the fill factor. The HgCdTe APD has a spectral response from 0.9- to 4.3-m wavelengths, a photon detection efficiency as high as 70%, and a dark count rate of <250 kHz at 110 K. The mass of the IDCA is 0.8 kg and the total electrical power consumption is about 7 W. The HgCdTe APD arrays have been characterized at NASA Goddard Space Flight Center. A series of environmental tests have been conducted for the IDCAs, including vibration, thermal cycling, and thermal vacuum tests. A description of the device and the test results at NASA are given in this paper

    Identification of the ancestral killer immunoglobulin-like receptor gene in primates

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    BACKGROUND: Killer Immunoglobulin-like Receptors (KIR) are essential immuno-surveillance molecules. They are expressed on natural killer and T cells, and interact with human leukocyte antigens. KIR genes are highly polymorphic and contribute vital variability to our immune system. Numerous KIR genes, belonging to five distinct lineages, have been identified in all primates examined thus far and shown to be rapidly evolving. Since few KIR remain orthologous between species, with only one of them, KIR2DL4, shown to be common to human, apes and monkeys, the evolution of the KIR gene family in primates remains unclear. RESULTS: Using comparative analyses, we have identified the ancestral KIR lineage (provisionally named KIR3DL0) in primates. We show KIR3DL0 to be highly conserved with the identification of orthologues in human (Homo sapiens), common chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla), rhesus monkey (Macaca mulatta) and common marmoset (Callithrix jacchus). We predict KIR3DL0 to encode a functional molecule in all primates by demonstrating expression in human, chimpanzee and rhesus monkey. Using the rhesus monkey as a model, we further show the expression profile to be typical of KIR by quantitative measurement of KIR3DL0 from an enriched population of natural killer cells. CONCLUSION: One reason why KIR3DL0 may have escaped discovery for so long is that, in human, it maps in between two related leukocyte immunoglobulin-like receptor clusters outside the known KIR gene cluster on Chromosome 19. Based on genomic, cDNA, expression and phylogenetic data, we report a novel lineage of immunoglobulin receptors belonging to the KIR family, which is highly conserved throughout 50 million years of primate evolution

    UV Absorption Lines from High-Velocity Gas in the Vela Supernova Remnant: New insights from STIS Echelle Observations of HD72089

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    The star HD72089 is located behind the Vela supernova remnant and shows a complex array of high and low velocity interstellar absorption features arising from shocked clouds. A spectrum of this star was recorded over the wavelength range 1196.4 to 1397.2 Angstroms at a resolving power lambda/Delta lambda = 110,000 and signal-to-noise ratio of 32 by STIS on the Hubble Space Telescope. We have identified 7 narrow components of C I and have measured their relative populations in excited fine-structure levels. Broader features at heliocentric velocities ranging from -70 to +130 km/s are seen in C II, N I, O I, Si II, S II and Ni II. In the high-velocity components, the unusually low abundances of N I and O I, relative to S II and Si II, suggest that these elements may be preferentially ionized to higher stages by radiation from hot gas immediately behind the shock fronts.Comment: 11 pages, 2 figures, Latex. Submitted for the special HST ERO issue of the Astrophysical Journal Letter

    Observational Study Design in Veterinary Pathology, Part 1: Study Design

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    Observational studies are the basis for much of our knowledge of veterinary pathology and are highly relevant to the daily practice of pathology. However, recommendations for conducting pathology-based observational studies are not readily available. In part 1 of this series, we offer advice on planning and conducting an observational study with examples from the veterinary pathology literature. Investigators should recognize the importance of creativity, insight, and innovation in devising studies that solve problems and fill important gaps in knowledge. Studies should focus on specific and testable hypotheses, questions, or objectives. The methodology is developed to support these goals. We consider the merits and limitations of different types of analytic and descriptive studies, as well as of prospective vs retrospective enrollment. Investigators should define clear inclusion and exclusion criteria and select adequate numbers of study subjects, including careful selection of the most appropriate controls. Studies of causality must consider the temporal relationships between variables and the advantages of measuring incident cases rather than prevalent cases. Investigators must consider unique aspects of studies based on archived laboratory case material and take particular care to consider and mitigate the potential for selection bias and information bias. We close by discussing approaches to adding value and impact to observational studies. Part 2 of the series focuses on methodology and validation of methods

    Annual cycle observations of aerosols capable of ice formation in central Arctic clouds

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    The Arctic is warming faster than anywhere else on Earth, prompting glacial melt, permafrost thaw, and sea ice decline. These severe consequences induce feedbacks that contribute to amplified warming, affecting weather and climate globally. Aerosols and clouds play a critical role in regulating radiation reaching the Arctic surface. However, the magnitude of their effects is not adequately quantified, especially in the central Arctic where they impact the energy balance over the sea ice. Specifically, aerosols called ice nucleating particles (INPs) remain understudied yet are necessary for cloud ice production and subsequent changes in cloud lifetime, radiative effects, and precipitation. Here, we report observations of INPs in the central Arctic over a full year, spanning the entire sea ice growth and decline cycle. Further, these observations are size-resolved, affording valuable information on INP sources. Our results reveal a strong seasonality of INPs, with lower concentrations in the winter and spring controlled by transport from lower latitudes, to enhanced concentrations of INPs during the summer melt, likely from marine biological production in local open waters. This comprehensive characterization of INPs will ultimately help inform cloud parameterizations in models of all scales

    Pipeline for Large-Scale Microdroplet Bisulfite PCR-Based Sequencing Allows the Tracking of Hepitype Evolution in Tumors

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    Cytosine methylation provides an epigenetic level of cellular plasticity that is important for development, differentiation and cancerogenesis. We adopted microdroplet PCR to bisulfite treated target DNA in combination with second generation sequencing to simultaneously assess DNA sequence and methylation. We show measurement of methylation status in a wide range of target sequences (total 34 kb) with an average coverage of 95% (median 100%) and good correlation to the opposite strand (rho = 0.96) and to pyrosequencing (rho = 0.87). Data from lymphoma and colorectal cancer samples for SNRPN (imprinted gene), FGF6 (demethylated in the cancer samples) and HS3ST2 (methylated in the cancer samples) serve as a proof of principle showing the integration of SNP data and phased DNA-methylation information into “hepitypes” and thus the analysis of DNA methylation phylogeny in the somatic evolution of cancer

    The emergence of synaesthesia in a Neuronal Network Model via changes in perceptual sensitivity and plasticity

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    Synaesthesia is an unusual perceptual experience in which an inducer stimulus triggers a percept in a different domain in addition to its own. To explore the conditions under which synaesthesia evolves, we studied a neuronal network model that represents two recurrently connected neural systems. The interactions in the network evolve according to learning rules that optimize sensory sensitivity. We demonstrate several scenarios, such as sensory deprivation or heightened plasticity, under which synaesthesia can evolve even though the inputs to the two systems are statistically independent and the initial cross-talk interactions are zero. Sensory deprivation is the known causal mechanism for acquired synaesthesia and increased plasticity is implicated in developmental synaesthesia. The model unifies different causes of synaesthesia within a single theoretical framework and repositions synaesthesia not as some quirk of aberrant connectivity, but rather as a functional brain state that can emerge as a consequence of optimising sensory information processing

    SAD phasing using iodide ions in a high-throughput structural genomics environment

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    The Seattle Structural Genomics Center for Infectious Disease (SSGCID) focuses on the structure elucidation of potential drug targets from class A, B, and C infectious disease organisms. Many SSGCID targets are selected because they have homologs in other organisms that are validated drug targets with known structures. Thus, many SSGCID targets are expected to be solved by molecular replacement (MR), and reflective of this, all proteins are expressed in native form. However, many community request targets do not have homologs with known structures and not all internally selected targets readily solve by MR, necessitating experimental phase determination. We have adopted the use of iodide ion soaks and single wavelength anomalous dispersion (SAD) experiments as our primary method for de novo phasing. This method uses existing native crystals and in house data collection, resulting in rapid, low cost structure determination. Iodide ions are non-toxic and soluble at molar concentrations, facilitating binding at numerous hydrophobic or positively charged sites. We have used this technique across a wide range of crystallization conditions with successful structure determination in 16 of 17 cases within the first year of use (94% success rate). Here we present a general overview of this method as well as several examples including SAD phasing of proteins with novel folds and the combined use of SAD and MR for targets with weak MR solutions. These cases highlight the straightforward and powerful method of iodide ion SAD phasing in a high-throughput structural genomics environment

    Crop Updates 2005 - Farming Systems

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    This session covers forty four papers from different authors: PLENARY 1. 2005 Outlook, David Stephens and Nicola Telcik, Department of Agriculture FERTILITY AND NUTRITION 2. The effect of higher nitrogen fertiliser prices on rotation and fertiliser strategies in cropping systems, Ross Kingwell, Department of Agriculture and University of Western Australia 3. Stubble management: The short and long term implications for crop nutrition and soil fertility, Wayne Pluske, Nutrient Management Systems and Bill Bowden, Department of Agriculture 4. Stubble management: The pros and cons of different methods, Bill Bowden, Department of Agriculture, Western Australia and Mike Collins, WANTFA 5. Effect of stubble burning and seasonality on microbial processes and nutrient recycling, Frances Hoyle, The University of Western Australia 6. Soil biology and crop production in Western Australian farming systems, D.V. Murphy, N. Milton, M. Osman, F.C. Hoyle, L.K Abbott, W.R. Cookson and S. Darmawanto, The University of Western Australia 7. Urea is as effective as CAN when no rain for 10 days, Bill Crabtree, Crabtree Agricultural Consulting 8. Fertiliser (N,P,S,K) and lime requirements for wheat production in the Merredin district, Geoff Anderson, Department of Agriculture and Darren Kidson, Summit Fertilizers 9. Trace element applications: Up-front verses foliar? Bill Bowden and Ross Brennan, Department of Agriculture 10. Fertcare®, Environmental Product Stewardship and Advisor Standards for thee Fertiliser Industry, Nick Drew, Fertilizer Industry Federation of Australia (FIFA) SOIL AND LAND MANAGEMENT 11. Species response to row spacing, density and nutrition, Bill Bowden, Craig Scanlan, Lisa Sherriff, Bob French and Reg Lunt, Department of Agriculture 12. Investigation into the influence of row orientation in lupin crops, Jeff Russell, Department of Agriculture and Angie Roe, Farm Focus Consultants 13. Deriving variable rate management zones for crops, Ian Maling, Silverfox Solutions and Matthew Adams, DLI 14. In a world of Precision Agriculture, weigh trailers are not passé, Jeff Russell, Department of Agriculture 15. Cover crop management to combat ryegrass resistance and improve yields, Jeff Russell, Department of Agriculture and Angie Roe, Farm Focus Consultants 16. ARGT home page, the place to find information on annual ryegrass toxicity on the web, Dr George Yan, BART Pty Ltd 17. Shallow leading tine (SLT) ripper significantly reduces draft force, improves soil tilth and allows even distribution of subsoil ameliorants, Mohammad Hamza, Glen Riethmuller and Wal Anderson, Department of Agriculture PASTURE ANS SUMMER CROP SYSTEMS 18. New annual pasture legumes for Mediteranean farming systems, Angelo Loi, Phil Nichols, Clinton Revell and David Ferris, Department of Agriculture 19. How sustainable are phase rotations with Lucerne? Phil Ward, CSIRO Plant Industry 20. Management practicalities of summer cropping, Andrea Hills and Sally-Anne Penny, Department of Agriculture 21. Rainfall zone determines the effect of summer crops on winter yields, Andrea Hills, Sally-Anne Penny and David Hall, Department of Agriculture 22. Summer crops and water use, Andrea Hills, Sally-Anne Penny and David Hall, Department of Agriculture, and Michael Robertson and Don Gaydon, CSIRO Brisbane 23. Risk analysis of sorgum cropping, Andrea Hills and Sally-Anne Penny, Department of Agriculture, and Dr Michael Robertson and Don Gaydon, CSIRO Brisbane FARMER DECISION SUPPORT AND ADOPTION 24. Variety release and End Point Royalties – a new system? Tress Walmsley, Department of Agriculture 25. Farming system analaysis using the STEP Tool, Caroline Peek and Megan Abrahams, Department of Agriculture 26. The Leakage Calculator: A simple tool for groundwater recharge assessment, Paul Raper, Department of Agriculture 27. The cost of Salinity Calculator – your tool to assessing the profitability of salinity management options, Richard O’Donnell and Trevor Lacey, Department of Agriculture 28. Climate decision support tools, Meredith Fairbanks and David Tennant, Department of Agriculture 29. Horses for courses – using the best tools to manage climate risk, Cameron Weeks, Mingenew-Irwin Group/Planfarm and Richard Quinlan, Planfarm Agronomy 30. Use of seasonal outlook for making N decisions in Merredin, Meredith Fairbanks and Alexandra Edward, Department of Agriculture 31. Forecasts and profits, Benefits or bulldust? Chris Carter and Doug Hamilton, Department of Agriculture 32. A tool to estimate fixed and variable header and tractor depreciation costs, Peter Tozer, Department of Agriculture 33. Partners in grain: ‘Putting new faces in new places’, Renaye Horne, Department of Agriculture 34. Results from the Grower group Alliance, Tracey Gianatti, Grower Group Alliance 35. Local Farmer Group Network – farming systems research opportunities through local groups, Paul Carmody, Local Farmer Group Network GREENHOUSE GAS AND CLIMATE CHANGE 36. Changing rainfall patterns in the grainbelt, Ian Foster, Department of Agriculture 37. Vulnerability of broadscale agriculture to the impacts of climate change, Michele John, CSIRO (formerly Department of Agriculture) and Ross George, Department of Agriculture 38. Impacts of climate change on wheat yield at Merredin, Imma Farré and Ian Foster, Department of Agriculture 39. Climate change, land use suitability and water security, Ian Kininmonth, Dennis van Gool and Neil Coles, Department of Agriculture 40. Nitrous oxide emissions from cropping systems, Bill Porter, Department of Agriculture, Louise Barton, University of Western Australia 41. The potential of greenhouse sinks to underwrite improved land management in Western Australia, Richard Harper and Peter Ritson, CRC for Greenhouse Accounting and Forest Products Commission, Tony Beck, Tony Beck Consulting Services, Chris Mitchell and Michael Hill, CRC for Greenhouse Accounting 42. Removing uncertainty from greenhouse emissions, Fiona Barker-Reid, Will Gates, Ken Wilson and Rob Baigent, Department of Primary Industries - Victoria and CRC for Greenhouse Accounting (CRCGA), and Ian Galbally, Mick Meyer and Ian Weeks, CSIRO Atmospheric Research and CRCGA 43. Greenhouse in Agriculture Program (GIA), Traci Griffin, CRC for Greenhouse Accounting 44. Grains Greenhouse Accounting framework, D. Rodriguez, M. Probust, M. Meyers, D. Chen, A. Bennett, W. Strong, R. Nussey, I. Galbally and M. Howden CONTACT DETAILS FOR PRINCIPAL AUTHOR
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