7,562 research outputs found

    Capabilities of a lobster eye telescope in the outer solar system

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    Current lobster eye telescopes demonstrate that itā€™s possible to produce light-weight, large field of view instruments for observing X-rays for both planetary science and astronomy. Jupiter is the most powerful particle accelerator in the solar system and the other outer planets have intricate and complicated magnetospheres which their moons often orbit within. Particle bombardment of the surfaces of their moons induces the emission of characteristic X-rays which enables their composition to be studied. An orbiting X-ray instrument would transform our understanding of the moonsā€™ composition, as well as the aurorae, atmosphere, plasma tori of outer planet systems and could also enable direct imaging of the entire radiation belt. Lobster eye telescopes are perfect for this application due to their light weight and wide field of view. This paper begins to identify a lobster eye telescope design to fulfil these science goals

    On a conjecture about Dirac's delta representation using q-exponentials

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    A new representation of Dirac's delta-distribution, based on the so-called q-exponentials, has been recently conjectured. We prove here that this conjecture is indeed valid

    NuSTAR detection of X-ray heating events in the quiet Sun

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    The explanation of the coronal heating problem potentially lies in the existence of nanoflares, numerous small-scale heating events occurring across the whole solar disk. In this Letter, we present the first imaging spectroscopy X-ray observations of three quiet Sun flares during the Nuclear Spectroscopic Telescope ARray (NuSTAR) solar campaigns on 2016 July 26 and 2017 March 21, concurrent with the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) observations. Two of the three events showed time lags of a few minutes between peak X-ray and extreme ultraviolet emissions. Isothermal fits with rather low temperatures in the range 3.2ā€“4.1 MK and emission measures of (0.6ā€“15) Ɨ 1044 cmāˆ’3 describe their spectra well, resulting in thermal energies in the range (2ā€“6) Ɨ 1026 erg. NuSTAR spectra did not show any signs of a nonthermal or higher temperature component. However, as the estimated upper limits of (hidden) nonthermal energy are comparable to the thermal energy estimates, the lack of a nonthermal component in the observed spectra is not a constraining result. The estimated Geostationary Operational Environmental Satellite (GOES) classes from the fitted values of temperature and emission measure fall between 1/1000 and 1/100 A class level, making them eight orders of magnitude fainter in soft X-ray flux than the largest solar flares

    Fit for work? Health, employability and challenges for the UK welfare reform agenda

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    This article introduces a special issue of Policy Studies entitled ā€œFit for work? Health, employability and challenges for the UK welfare reform agendaā€. Growing from a shared concern over the need to expand the evidence base around the processes that led to large numbers of people claiming disability benefits in the UK, it brings together contributions from leading labour market and social policy researchers providing evidence and commentary on major reforms to Incapacity Benefit (IB) in the UK. This special issue address three key questions: what are the main causes of the long-term rise in the number of people claiming IBs; what will reduce the number of claimants; and what is likely to deliver policy effectively and efficiently? This introduction first explains and examines the challenges to reforms to IB in the UK, and then, in conclusion, highlights the answers to the previous three questions ā€“ first, labour market restructuring and marginalisation have driven the rise in numbers claiming IBs. Second, economic regeneration in the Britainā€™s less prosperous areas coupled with intensive and sustained supply-side support measures will bring numbers down. Third, delivery need to be flexible and tailored to individual needs and needs to be able to access local and expert knowledge in a range of organisations, including Job Centre Plus, the NHS as well as the private and voluntary sectors
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