2,491 research outputs found

    Probing the interiors of the ice giants: Shock compression of water to 700 GPa and 3.8 g/ccm

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    Recently there has been tremendous increase in the number of identified extra-solar planetary systems. Our understanding of their formation is tied to exoplanet internal structure models, which rely upon equations of state of light elements and compounds like water. Here we present shock compression data for water with unprecedented accuracy that shows water equations of state commonly used in planetary modeling significantly overestimate the compressibility at conditions relevant to planetary interiors. Furthermore, we show its behavior at these conditions, including reflectivity and isentropic response, is well described by a recent first-principles based equation of state. These findings advocate this water model be used as the standard for modeling Neptune, Uranus, and "hot Neptune" exoplanets, and should improve our understanding of these types of planets.Comment: Accepted to Phys. Rev. Lett.; supplementary material attached including 2 figures and 2 tables; to view attachments, please download and extract the gzipped tar source file listed under "Other formats

    QUALITATIVE BIOMECHANICS FOR COACHING

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    Session Information: Coaches must apply principles of biomechanics in their qualitative judgments of the technique used by athletes. These judgments can have a major influence on performance and injury risk. This session will focus on the most effective use of qualitative biomechanical analyses and video replay software. Several scholars who have experience teaching qualitative biomechanical analysis to future coaches will present, followed by a question and answer session. Schedule of Presentations: Dr. Knudson will introduce the session and provide a brief overview of qualitative biomechanical analysis. 11:00 – 11:15 Dr. Alderson will present sport injury models as they apply to assessment, intervention and rehabilitation of common injuries in cricket, tennis and running. Relevant qualitative and quantitative 2D features of SiliconCoach that can be utilised by a coach to potentially reduce injury incidence will be presented. 11:15 – 11:45 Dr. Bahamonde will present how qualitative analysis can be used to teach biomechanics concepts to physical education and coaching students. Movement examples from tennis, soccer and track field and meaningful features of Hu-m-an software will be illustrated. Hu-m-an is unique in that it was developed with a specific teaching-learning focus. 11:45 – 12:15 Dr. Bird will present biomechanical core concepts as a “common language” to evaluate and improve all human movements. The core concepts are visually observable, but meaningful features of Dartfish will be illustrated to enhance what is seen by both the coach and the mover. Movement examples from golf, resistance training, basketball, and other sports will be presented. 12:15 – 12:45 Discussion: 12:45 – 13:00 This will provide an opportunity for delegates to ask specific questions relating to any of the presenters

    Performance of Large-Volume Mean-Timed Neutron Detectors

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    Supported by the National Science Foundation and Indiana Universit

    Differential cross sections for pion charge exchange on the proton at 27.5 MeV

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    We have measured pion single charge exchange differential cross sections on the proton at 27.5 MeV incident π\pi^- kinetic energy in the center of momentum angular range between 00^\circ and 5555^\circ. The extracted cross sections are compared with predictions of the standard pion-nucleon partial wave analysis and found to be in excellent agreement.Comment: ReVTeX v3.0 with aps.sty, 23 pages in e-print format, 7 PostScript Figures and 4 Tables, also available via anonymous ftp at ftp://helena.phys.virginia.edu/pub/preprints/scx.p

    High-Spin States in Nuclei Excited Via the (p,n) Reactions

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    Supported by the National Science Foundation and Indiana Universit

    Accumulation of driver and passenger mutations during tumor progression

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    Major efforts to sequence cancer genomes are now occurring throughout the world. Though the emerging data from these studies are illuminating, their reconciliation with epidemiologic and clinical observations poses a major challenge. In the current study, we provide a novel mathematical model that begins to address this challenge. We model tumors as a discrete time branching process that starts with a single driver mutation and proceeds as each new driver mutation leads to a slightly increased rate of clonal expansion. Using the model, we observe tremendous variation in the rate of tumor development - providing an understanding of the heterogeneity in tumor sizes and development times that have been observed by epidemiologists and clinicians. Furthermore, the model provides a simple formula for the number of driver mutations as a function of the total number of mutations in the tumor. Finally, when applied to recent experimental data, the model allows us to calculate, for the first time, the actual selective advantage provided by typical somatic mutations in human tumors in situ. This selective advantage is surprisingly small, 0.005 +- 0.0005, and has major implications for experimental cancer research
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