807 research outputs found

    POEMMA: Probe Of Extreme Multi-Messenger Astrophysics

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    The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) mission is being designed to establish charged-particle astronomy with ultra-high energy cosmic rays (UHECRs) and to observe cosmogenic tau neutrinos (CTNs). The study of UHECRs and CTNs from space will yield orders-of-magnitude increase in statistics of observed UHECRs at the highest energies, and the observation of the cosmogenic flux of neutrinos for a range of UHECR models. These observations should solve the long-standing puzzle of the origin of the highest energy particles ever observed, providing a new window onto the most energetic environments and events in the Universe, while studying particle interactions well beyond accelerator energies. The discovery of CTNs will help solve the puzzle of the origin of UHECRs and begin a new field of Astroparticle Physics with the study of neutrino properties at ultra-high energies.Comment: 8 pages, in the Proceedings of the 35th International Cosmic Ray Conference, ICRC217, Busan, Kore

    The POEMMA (Probe of Extreme Multi-Messenger Astrophysics) mission

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    The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is designed to observe cosmic neutrinos (CNs) above 20 PeV and ultra-high energy cosmic rays (UHECRs) above 20 EeV over the full sky. The POEMMA mission calls for two identical satellites flying in loose formation, each comprised of a 4-meter wide field-of-view (45 degrees) Schmidt photometer. The hybrid focal surface includes a fast (1 μ{\mu}s) ultraviolet camera for fluorescence observations and an ultrafast (10 ns) optical camera for Cherenkov observations. POEMMA will provide new multi-messenger windows onto the most energetic events in the universe, enabling the study of new astrophysics and particle physics at these otherwise inaccessible energies.Comment: 8 pages, 6 figures, presented in 36th International Cosmic Ray Conference (Madison). arXiv admin note: substantial text overlap with arXiv:1907.0621

    Low back pain in 17 year olds has substantial impact and represents an important public health disorder: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Prevalence of low back pain (LBP) rises rapidly during adolescence, reaching adult levels by the age of 18. It has been suggested that adolescent LBP is benign with minimal impact, despite limited evidence.</p> <p>Methods</p> <p>The aim of this study was to investigate the impact of LBP and the influence of chronicity, gender and presence of other spinal pain comorbidities at age 17. Subjects (n = 1283) were categorised according to experiencing current and chronic LBP, gender and presence of other areas of spinal pain. LBP impact was ascertained via questions regarding seeking professional assistance, using medication, missing school/work, limited normal or recreational physical activity and health related quality of life (HRQOL).</p> <p>Results</p> <p>12.3% of participants reported current but not chronic LBP, while 19.9% reported current chronic LBP. LBP was more commonly reported by females than males. Other spinal pain comorbidities were common in the LBP groups. Impact was greater in subjects with chronic LBP, in females and in those with other spinal pain comorbidities.</p> <p>Conclusion</p> <p>LBP, and particularly chronic LBP, has a significant negative impact at 17 years. It is commonly associated with care seeking, medication use, school absenteeism, and reduced HRQOL. These findings support that adolescent LBP is an important public health issue that requires attention.</p

    The Roadmap to the POEMMA mission

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    The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is designed to observe ultrahigh-energy cosmic rays (UHECRs) and cosmic neutrinos from space with sensitivity over the full celestial sky. Developed as a NASA Astrophysics Probe-class mission, POEMMA consists of two identical telescopes orbiting the Earth in a loose formation designed to observe extensive air showers (EAS) via air fluorescence and Cherenkov emissions. UHECRs and UHE neutrinos above 20 EeV are observed with the stereo fluorescence technique, while tau neutrinos above 20 PeV are observed via the optical Cherenkov signals produced by up-going EAS generated by the decay of Earth-emerging tau-leptons. The POEMMA satellites are designed to quickly re-orientate to follow up transient cosmic neutrino candidate sources and obtain unparalleled neutrino flux sensitivity. Both observation techniques and the instrument design are being validated by current and upcoming missions, such as Mini-EUSO and EUSO-SPB as part of the JEM-EUSO program, and the Terzina instrument onboard the NUSES SmallSat mission. We discuss the POEMMA science performance and the current roadmap to the POEMMA mission

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    Protein/DNA interactions in complex DNA topologies: expect the unexpected

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    DNA supercoiling results in compacted DNA structures that can bring distal sites into close proximity. It also changes the local structure of the DNA, which can in turn influence the way it is recognised by drugs, other nucleic acids and proteins. Here, we discuss how DNA supercoiling and the formation of complex DNA topologies can affect the thermodynamics of DNA recognition. We then speculate on the implications for transcriptional control and the three-dimensional organisation of the genetic material, using examples from our own simulations and from the literature. We introduce and discuss the concept of coupling between the multiple length-scales associated with hierarchical nuclear structural organisation through DNA supercoiling and topology
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