53 research outputs found

    128Xe and 130Xe: Testing He-shell burning in AGB stars

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    The s-process branching at 128I has been investigated on the basis of new, precise experimental (n,g) cross sections for the s-only isotopes 128Xe and 130Xe. This branching is unique, since it is essentially determined by the temperature- and density-sensitive stellar decay rates of 128I and only marginally affected by the specific stellar neutron flux. For this reason it represents an important test for He-shell burning in AGB stars. The description of the branching by means of the complex stellar scenario reveals a significant sensitivity to the time scales for convection during He shell flashes, thus providing constraints for this phenomenon. The s-process ratio 128Xe/130Xe deduced from stellar models allows for a (9+-3)% p-process contribution to solar 128Xe, in agreement with the Xe-S component found in meteoritic presolar SiC grains.Comment: 24 pages, 9 figures, accepted for publication in Astophysical Journa

    Recognition of the Phanerozoic “Young Granite Gneiss” in the central Yeongnam Massif

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    Up to now, all the high-grade gneisses of the Korean peninsula have been regarded as Precambrian basement rocks and presence of the Phanerozoic high-grade metamorphic rocks have remained unknown. However, such granite gneiss is discovered through this study from the central Yeongnam massif near Gimcheon. SHRIMP zircon U-Pb age determinations on the granite gneiss, having well-developed gneissic foliations and migmatitic textures, reveal concordant age of ca. 250 Ma indicating the Early Triassic emplacement of this pluton, which is in contradict to the previous belief that it is a Precambrian product. Even though the granite gneiss reveals well-developed gneissic foliations and some zircons show rather low Th/U ratios, the metamorphic age has not been determined successfully. However, the age of metamorphism can be constrained as middle Triassic considering the absence of any evidences of metamorphism from the nearby granitic plutons having emplacement ages of ca. 225 Ma. Early Triassic emplacement and subsequent Middle Triassic metamorphism of the granite gneiss from the Yeongnam massif bear a remarkable resemblance to the case of South China block. We suggest the possibility that Early to Middle Triassic metamorphism of the Korean peninsula might be products of the intracontinental collisional events not directly related with the Early Triassic continental collision event

    Long-term monitoring of the ANTARES optical module efficiencies using K-40 decays in sea water

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    [EN] Cherenkov light induced by radioactive decay products is one of the major sources of background light for deep-sea neutrino telescopes such as ANTARES. These decays are at the same time a powerful calibration source. Using data collected by the ANTARES neutrino telescope from mid 2008 to 2017, the time evolution of the photon detection ef¿ciency of optical modules is studied. A modest loss of only 20% in 9 years is observed. The relative time calibration between adjacent modules is derived as well.Albert, A.; Andre, M.; Anghinolfi, M.; Anton, G.; Ardid Ramírez, M.; Aubert, J.; Aublin, J.... (2018). Long-term monitoring of the ANTARES optical module efficiencies using K-40 decays in sea water. The European Physical Journal C. 78(8):1-8. https://doi.org/10.1140/epjc/s10052-018-6132-2S18788M. Ageron et al., ANTARES: The first undersea neutrino telescope. Nuclear Instruments and Methods in Physics Research A 656, 11–38 (2011)A. Albert et al., First all-flavor neutrino pointlike source search with the ANTARES neutrino telescope. Physical Review D 96, 082001 (2017)A. Albert et al., All-flavor Search for a Diffuse Flux of Cosmic Neutrinos with Nine Years of ANTARES Data. The Astrophysical Journal Letters 853, L7 (2018)B.P. Abbott et al., Multi-messenger Observations of a Binary Neutron Star Merger. The Astrophysical Journal Letters 848, L12 (2017)S. Adrián-Martínez et al., Measurement of atmospheric neutrino oscillations with the ANTARES neutrino telescope. Physics Letters B 714, 224–230 (2012)A. Albert et al., Search for relativistic magnetic monopoles with five years of the ANTARES detector data. Journal of High Energy Physics 7, 54 (2017)S. Adrián-Martínez et al., Limits on dark matter annihilation in the sun using the ANTARES neutrino telescope. Physics Letters B 759, 69–74 (2016)A. Albert et al., Results from the search for dark matter in the Milky Way with 9 years of data of the ANTARES neutrino telescope. Physics Letters B 769, 249–254 (2017)M.G. Aartsen et al., The IceCube Neutrino Observatory: instrumentation and online systems. Journal of Instrumentation 12, P03012 (2017)K. Abe et al., Calibration of the Super-Kamiokande detector. Nuclear Instruments and Methods in Physics Research A 737, 253–272 (2014)P. Amram et al., The ANTARES optical module. Nuclear Instruments and Methods in Physics Research A 484, 369–383 (2002)S. Adrián-Martínez et al., The positioning system of the ANTARES Neutrino Telescope. Journal of Instrumentation 7, T08002 (2012)J.A. Aguilar et al., Performance of the front-end electronics of the ANTARES neutrino telescope. Nuclear Instruments and Methods in Physics Research A 622, 59–73 (2010)J.A. Aguilar et al., The data acquisition system for the ANTARES neutrino telescope. Nuclear Instruments and Methods in Physics Research A 570, 107–116 (2007)J.A. Aguilar et al., Measurement of the atmospheric muon flux with a 4 GeV threshold in the ANTARES neutrino telescope. Astroparticle Physics 33, 86–90 (2010)J.A. Aguilar et al., Transmission of light in deep sea water at the site of the ANTARES neutrino telescope. Astroparticle Physics 23, 131–155 (2005)S. Kim et al., PubChem Substance and Compound databases. Nucleic Acids Research 44, 1202–13 (2016)G. Audi et al., The NUBASE evaluation of nuclear and decay properties. Nuclear Physics A 729, 3–128 (2003)J. Floor Anthoni. The chemical composition of seawater. http://www.seafriends.org.nz/oceano/seawater.htmJ.R. De Laeter et al., Atomic Weights of the Elements: Review 2000 (IUPAC Technical Report). Pure Applied Chemistry 75, 683–800 (2003)P. Amram et al., Background light in potential sites for the ANTARES undersea neutrino telescope. Astroparticle Physics 13, 127–136 (2000)C. Tamburini et al., Deep-sea bioluminescence blooms after dense water formation at the ocean surface. PLOS ONE, 8(7), (2013)J.A. Aguilar et al., Time calibration of the ANTARES neutrino telescope. Astroparticle Physics 34, 539–549 (2011)M. Ageron et al., The ANTARES optical beacon system. Nuclear Instruments and Methods in Physics Research A 578, 498–509 (2007)S. Adrián-Martínez et al., Time calibration with atmospheric muon tracks in the ANTARES neutrino telescope. Astroparticle Physics 78, 43–51 (2016)S. Adrián-Martínez et al., Letter of Intent for KM3NeT 2.0. Journal of Physics G. Nuclear Physics 43(8), 084001 (2016

    Assessing human diet and movement in the Tongan maritime chiefdom using isotopic analyses.

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    The rise of stratified societies fundamentally influences the interactions between status, movement, and food. Using isotopic analyses, we assess differences in diet and mobility of individuals excavated from two burial mounds located at the `Atele burial site on Tongatapu, the main island of the Kingdom of Tonga (c. 500 - 150 BP). The first burial mound (To-At-1) was classified by some archaeologists as a commoner's mound while the second burial mound (To-At-2) was possibly used for interment of the chiefly class. In this study, stable isotope analyses of diet (δ13C, δ15N, and δ34S; n = 41) are used to asses paleodiet and 87Sr/86Sr ratios (n = 30) are analyzed to investigate individual mobility to test whether sex and social status affected these aspects of life. Our results show significant differences in diet between burial mounds and sexes. Those interred in To-At-2 displayed lower δ13C values, indicating they ate relatively more terrestrial plants (likely starchy vegetable staples) compared with To-At-1 individuals. Females displayed significantly lower δ15N values compared with males within the entire assemblage. No differences in δ34S values were observed between sexes or burial mound but it is possible that sea spray or volcanism may have affected these values. One individual displayed the strontium isotopic composition representative of a nonlocal immigrant (outside 2SD of the mean). This suggests the hegemonic control over interisland travel, may have prevented long-term access to the island by non-Tongans exemplifying the political and spiritual importance of the island of Tongatapu in the maritime chiefdom

    Prediction of product ion isotope ratios in the tandem electrospray ionization mass spectra from the second isotope of tryptic peptides: identification of the variant β131 Gln→Glu, hemoglobin camden

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    Many human hemoglobin variants occur in heterozygotes; that is, the variant and normal hemoglobins are present in the same sample. In a procedure for rapidly identifying such variants by mass spectrometry, mutations that increase the mass by I Da require a special approach. One of the steps in this procedure involves digesting the denatured hemoglobin with trypsin and analyzing the resulting peptide mixture by mass spectrometry to identify the mutant peptide. Generally the mutant peptide ion can then be selected as the precursor and sequenced by tandem mass spectrometry to identify or confirm the mutation. However, with heterozygotes in which the mass of the variant is 1 Da higher than normal, the first isotope of the mutant peptide occurs at essentially the same mass as the second isotope of the normal peptide, precluding analysis of the mutant peptide on its own. Product ions from the second isotope of a peptide are doublets, I Da apart. The way in which the relative abundance of the components in these doublets varies with the elemental composition of the product ions was predicted from the isotopic abundance of the elements and agreed well with experimental data. These results were applied to the identification of a variant that increases the mass by 1 Da in a heterozygote-that is, beta 131 Gln -> Glu, hemoglobin Camden
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