33 research outputs found

    Understanding space weather to shield society: A global road map for 2015-2025 commissioned by COSPAR and ILWS

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    There is a growing appreciation that the environmental conditions that we call space weather impact the technological infrastructure that powers the coupled economies around the world. With that comes the need to better shield society against space weather by improving forecasts, environmental specifications, and infrastructure design. [...] advanced understanding of space weather requires a coordinated international approach to effectively provide awareness of the processes within the Sun-Earth system through observation-driven models. This roadmap prioritizes the scientific focus areas and research infrastructure that are needed to significantly advance our understanding of space weather of all intensities and of its implications for society. Advancement of the existing system observatory through the addition of small to moderate state-of-the-art capabilities designed to fill observational gaps will enable significant advances. Such a strategy requires urgent action: key instrumentation needs to be sustained, and action needs to be taken before core capabilities are lost in the aging ensemble. We recommend advances through priority focus (1) on observation-based modeling throughout the Sun-Earth system, (2) on forecasts more than 12 hrs ahead of the magnetic structure of incoming coronal mass ejections, (3) on understanding the geospace response to variable solar-wind stresses that lead to intense geomagnetically-induced currents and ionospheric and radiation storms, and (4) on developing a comprehensive specification of space climate, including the characterization of extreme space storms to guide resilient and robust engineering of technological infrastructures. The roadmap clusters its implementation recommendations by formulating three action pathways, and outlines needed instrumentation and research programs and infrastructure for each of these. [...]Comment: In press for Advances of Space Research: an international roadmap on the science of space weather, commissioned by COSPAR and ILWS (63 pages and 4 figures

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Remarkable transition from rocksalt/perovskite layered structure to fluorite/rocksalt layered structure in rapidly cooled Ln2CuO4

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    This work was supported by EPSRCLanthanide cuprates of formula Ln2CuO4 exist in two principal forms, T and T′ which are renowned for their exhibition at low temperatures of hole and electronic types of superconductivity, respectively. These structures differ primarily in the arrangement of oxygen between the perovskite layers and also in nature of the copper oxygen planes. The Cu-O distance in the T structure (~1.90 Å) is much shorter than the T′ (1.97Å), reflecting a transition between partial Cu+ and partial Cu3+ character. In seeking to find compositions that bridge these two structure/electron carrier types, we observed the transition from a T structure to a T′ type structure, resulting in the metastable form T″ with slightly larger volume but similar character to T′. This transition from T to T″ is associated with 5% increase in a and a 5% decrease in c parameters of the tetragonal unit cells, which results in disintegration of ceramic bodies.Publisher PDFPeer reviewe
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