894 research outputs found

    High-Energy Neutrino Astronomy

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    Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the observational fact that Nature accelerates protons and photons to energies in excess of 102010^{20} and 101310^{13} eV, respectively. The cosmic ray connection sets the scale of cosmic neutrino fluxes. In this context, we discuss the first results of the completed AMANDA detector and the reach of its extension, IceCube. Similar experiments are under construction in the Mediterranean. Neutrino astronomy is also expanding in new directions with efforts to detect air showers, acoustic and radio signals initiated by super-EeV neutrinos.Comment: 9 pages, Latex2e, uses ws-procs975x65standard.sty (included), 4 postscript figures. To appear in Proceedings of Thinking, Observing, and Mining the Universe, Sorrento, Italy, September 200

    Nonthermal X-radiation of SNR RX J1713.7-3946: The Relations to a Nearby Molecular Cloud

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    The recent X-ray and CO observations of RX J1713.7-3946 show that a significant fraction of the nonthermal X-ray emission of this unique supernova remnant associates, in one way or another, with a molecular cloud interacting with the west part of the shell. This adds a new puzzle in the origin of X-ray emission which cannot be easily explained within the standard model in accordance of which X-rays are result of synchrotron radiation of multi-TeV electrons accelerated by supernova shock waves. We explore an alternative origin of the X-ray emission assuming that it is produced by secondary electrons resulting from high energy hadronic interactions in the molecular gas. Such a scenario could explain in a quite natural way the apparent correlation between the X-ray and CO morphologies. However, the TeV gamma-ray emission recently reported by H.E.S.S. significantly constrains the parameter space of this model. Namely, this mechanism cannot reproduce the bulk of the observed X-ray flux unless one postulates existence of a PeV cosmic-ray component penetrating with an unusually hard spectrum into the dense cloud.Comment: 6 pages, 3 figures, to appear in Proc. of Int. Symp. on High Energy Gamma-ray Astronomy, Heidelberg (July 2004

    Computationally designed libraries of fluorescent proteins evaluated by preservation and diversity of function

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    To determine which of seven library design algorithms best introduces new protein function without destroying it altogether, seven combinatorial libraries of green fluorescent protein variants were designed and synthesized. Each was evaluated by distributions of emission intensity and color compiled from measurements made in vivo. Additional comparisons were made with a library constructed by error-prone PCR. Among the designed libraries, fluorescent function was preserved for the greatest fraction of samples in a library designed by using a structure-based computational method developed and described here. A trend was observed toward greater diversity of color in designed libraries that better preserved fluorescence. Contrary to trends observed among libraries constructed by error-prone PCR, preservation of function was observed to increase with a library's average mutation level among the four libraries designed with structure-based computational methods

    Suzaku X-Ray Imaging and Spectroscopy of Cassiopeia A

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    Suzaku X-ray observations of a young supernova remnant, Cassiopeia A, were carried out. K-shell transition lines from highly ionized ions of various elements were detected, including Chromium (Cr-Kalpha at 5.61 keV). The X-ray continuum spectra were modeled in the 3.4--40 keV band, summed over the entire remnant, and were fitted with a simplest combination of the thermal bremsstrahlung and the non-thermal cut-off power-law models. The spectral fits with this assumption indicate that the continuum emission is likely to be dominated by the non-thermal emission with a cut-off energy at > 1 keV. The thermal-to-nonthermal fraction of the continuum flux in the 4-10 keV band is best estimated as ~0.1. Non-thermal-dominated continuum images in the 4--14 keV band were made. The peak of the non-thermal X-rays appears at the western part. The peak position of the TeV gamma-rays measured with HEGRA and MAGIC is also shifted at the western part with the 1-sigma confidence. Since the location of the X-ray continuum emission was known to be presumably identified with the reverse shock region, the possible keV-TeV correlations give a hint that the accelerated multi-TeV hadrons in Cassiopeia A are dominated by heavy elements in the reverse shock region.Comment: Publ. Astron. Soc. Japan 61, pp.1217-1228 (2009

    The RIF1-Long splice variant promotes G1 phase 53BP1 nuclear bodies to protect against replication stress

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    Acknowledgements Thanks to members of the Aberdeen Chromosome Biology Group for helpful comments, and Ronan Broderick and Wojciech Niedzwiedz for advice on mitotic bridge analysis. We thank Raif Yuecel and his team at the Iain Fraser Cytometry Centre for assistance, and Kevin Mackenzie and his team at the Microscopy and Histology Core Facility. Work was supported by Cancer Research UK Studentship Award C1445/A20596 and CRUK Programme Award C1445/A19059; by JSPS KAKENHI Grants Numbers 17K15068, 18H02170 and 18H04719; by research grants from the Daiichi Sankyo’s Foundation of Life Science and the Takeda Science Foundation; and by the UK Medical Research Council (MC_UU_00007/13). Collaboration was supported by a 2017 JSPS Summer Programme Fellowship. Funding Cancer Research UK (C1445/A20596) Anne D Donaldson Cancer Research UK (C1445/A19059) Anne D Donaldson Japan Society for the Promotion of Science (17K15068) Masato T Kanemaki Japan Society for the Promotion of Science (18H02170) Masato T Kanemaki Japan Society for the Promotion of Science (18H04719) Masato T Kanemaki Medical Research Council (MC_UU_00007/13) Nick GilbertPeer reviewedPublisher PD
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