977 research outputs found

    New Nomenclature Rules for Meteor Showers Adopted

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    The Shower Database (SD) of the Meteor Data Center (MDC) had been operating on the basis of stream-naming rules which were too complex and insufficiently precise for 15 years. With a gradual increase in the number of discovered meteor showers, the procedure for submitting new showers to the database and naming them lead to situations that were inconsistent with the fundamental role of the SD - the disambiguation of stream names in the scientific literature. Our aim is to simplify the meteor shower nomenclature rules. We propose a much simpler set of meteor shower nomenclature rules, based on a two-stage approach, similar to those used in the case of asteroids. The first stage applies to a new shower just after its discovery. The second stage concerns the repeatedly observed shower, the existence of which no longer raises any doubts. Our proposed new procedure was approved by a vote of the commission F1 of the IAU in July 2022.Comment: Submitted to: New Astronomy Review

    Modification of the Shower Database of the IAU Meteor Data Center

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    The Shower Database (SD) of the Meteor Data Center (MDC) has been operating for 15 years and is used by the entire community of meteor astronomers. It contains meteor showers categorised in individual lists on the basis of their status. Since the inception of the SD, no objective rules for moving showers between individual lists have been established. The content of the SD has not yet been checked for the correctness of the meteor data contained therein. Our aims are (1) to formulate criteria for nominating meteor showers for established status, (2) to improve the rules for the removal of showers, (3) to verify and enhance the content of the SD, and (4) to improve the user area of the MDC SD. The criteria for moving showers from the Working list to the Lists of established or removed Showers were generated using an empirical evaluation of their impact on the registered showers. The correctness of the parameters of each stream included in the SD was checked by comparing them with the values given in the source publications. We developed a set of criteria for nominating showers to be established. We objectified rules for the temporary and permanent removal of meteor showers from the Working list. Both of our proposed new procedures were approved by a vote of the commission F1 of the IAU in July 2022. We verified more than 13501350 data records of the MDC SD and introduced \sim1700 corrections. We included new parameters for shower characterisation. As a result of our verification procedure, 117 showers have been moved to the List of removed showers. As of October 2022, the SD contains 923 showers, 110 of which are in the List of established Showers and 813 are in the Working list. We also improved the user area of the SD and added a simple tool to allow a quick check of the similarity of a new shower to those in the database

    TOPORS (topoisomerase I binding, arginine/serine-rich)

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    Review on TOPORS (topoisomerase I binding, arginine/serine-rich), with data on DNA, on the protein encoded, and where the gene is implicated

    Deformation and cyclic strength characteristics of loose and medium-dense clean sand under sloping ground conditions: insights from cyclic undrained torsional shear tests with static shear

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    The effects of liquefaction on sloping ground often include the development of extremely large deformation. Although such phenomenon has been repeatedly observed following major earthquakes, the triggering conditions are not fully understood yet. To provide new insights into this issue, in this paper, results of two series of large-strain undrained cyclic torsional shear tests with initial static shear conducted on loose and medium-dense Toyoura sand specimens (relative density of 25-30% and 44-48%) are presented and analyzed. The post-liquefaction response of Toyoura sand is assessed in terms of failure modes and cyclic resistance up to 50% single amplitude shear strain. It is shown that, depending on the combined magnitude of static and cyclic shear stresses, a sand in sloping ground will likely experience a sudden development of large shear deformation (flow deformation) if initial liquefaction takes place, or a more progressive accumulation of large residual deformation, which yet may bring sand to failure, when the onset of initial liquefaction is not achieved

    Development and operational experience of magnetic horn system for T2K experiment

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    A magnetic horn system to be operated at a pulsed current of 320 kA and to survive high-power proton beam operation at 750 kW was developed for the T2K experiment. The first set of T2K magnetic horns was operated for over 12 million pulses during the four years of operation from 2010 to 2013, under a maximum beam power of 230 kW, and 6.63×10206.63\times10^{20} protons were exposed to the production target. No significant damage was observed throughout this period. This successful operation of the T2K magnetic horns led to the discovery of the νμνe\nu_{\mu}\rightarrow\nu_e oscillation phenomenon in 2013 by the T2K experiment. In this paper, details of the design, construction, and operation experience of the T2K magnetic horns are described.Comment: 22 pages, 40 figures, also submitted to Nuclear Instrument and Methods in Physics Research,
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