3,286 research outputs found

    Regularities with random interactions in energy centroids defined by group symmetries

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    Regular structures generated by random interactions in energy centroids defined over irreducible representations (irreps) of some of the group symmetries of the interacting boson models sdsdIBM, sdgsdgIBM, sdsdIBM-TT and sdsdIBM-STST are studied by deriving trace propagations equations for the centroids. It is found that, with random interactions, the lowest and highest group irreps in general carry most of the probability for the corresponding centroids to be lowest in energy. This generalizes the result known earlier, via numerical diagonalization, for the more complicated fixed spin (JJ) centroids where simple trace propagation is not possible.Comment: 18 pages, 3 figure

    High-j single-particle neutron states outside the N=82 core

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    The behaviour of the i13/2 and h9/2 single-neutron strength was studied with the (4He,3He) reaction on 138Ba, 140Ce, 142Nd and 144Sm targets at a beam energy of 51 MeV. The separation between the single-neutron states i13/2 and h9/2 was measured in N =83 nuclei with changing proton number. To this end spectroscopic factors for states populated in high-l transfer were extracted from the data. Some mixing of l=5 and 6 strength was observed with states that are formed by coupling the f7/2 state to the 2+ and 3- vibrational states and the mixing matrix elements were found to be remarkably constant. The centroids of the strength indicate a systematic change in the energies of the i13/2 and h9/2 single-neutron states with increasing proton number that is in quantitative agreement with the effects expected from the tensor interaction.Comment: 12 pages of text, 3 diagram

    Frailty, Psychoactive Medications, and Cognitive Dysfunction Are Associated With Poor Patient‐Reported Outcomes in Cirrhosis

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148384/1/hep30336-sup-0001-Supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148384/2/hep30336_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148384/3/hep30336.pd

    Interval gangrene complicating superficial femoral artery stent placement

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    Interval gangrene—necrosis of tissue proximal to a successful distal revascularization procedure—is an exceeding rare complication. To date, only nine cases have been reported in the literature, and all were secondary to traditional open bypass procedures. We report the first case, to our knowledge, of interval gangrene after endovascular stent placement in the superficial femoral artery. We believe that with the increasing utilization of endovascular techniques to treat limb ischemia, the serious complication of interval gangrene must be revisited. Assessment of collateral circulation, precise stent placement, and the appropriate choice of stents and stent grafts will become increasing important as more and more of these lesions are treated with endovascular techniques

    Thermonuclear Ti-42(p, gamma)V-43 rate in type-I x-ray bursts

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    The thermonuclear rate of the Ti-42(p, gamma)V-43 reaction has been reevaluated based on a recent precise proton separation energy measurement of S-p(V-43) = 83 +/- 43 keV. The astrophysical impact of our new rates has been investigated through one-zone postprocessing type-I x-ray burst calculations. It shows that the new experimental value of S-p significantly affects the yields of species for A approximate to 40-45. As well, the precision of the recent experimental S-p value constrains these yields to better than a factor of 3.Peer reviewedFinal Accepted Versio

    Double Charge Exchange And Configuration Mixing

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    The energy dependence of forward pion double charge exchange reactions on light nuclei is studied for both the Ground State transition and the Double-Isobaric-Analog-State transitions. A common characteristic of these double reactions is a resonance-like peak around 50 MeV pion lab energy. This peak arises naturally in a two-step process in the conventional pion-nucleon system with proper handling of nuclear structure and pion distortion. A comparison among the results of different nuclear structure models demonstrates the effects of configuration mixing. The angular distribution is used to fix the single particle wave function.Comment: Added 1 figure (now 8) corrected references and various other change

    Unexpected late-time temperature increase observed in two neutron star crust cooling sources -- XTE~J1701-462 and EXO~0748-676

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    Transient LMXBs that host neutron stars (NSs) provide excellent laboratories for probing the dense matter physics present in NS crusts. During accretion outbursts in LMXBs, exothermic reactions may heat the NS crust, disrupting the crust-core equilibrium. When the outburst ceases, the crust cools to restore thermal equilibrium with the core. Monitoring this evolution allows us to probe the dense matter physics in the crust. Properties of the deeper crustal layers can be probed at later times after the end of the outburst. We report on the unexpected late-time temperature evolution (>2000 days after the end of their outbursts) of two NSs in LMXBs, XTE J1701-462 and EXO 0748-676. Although both these sources exhibited very different outbursts (in terms of duration and the average accretion rate), they exhibit an unusually steep decay of ~7 eV in the observed effective temperature (occurring in a time span of ~700 days) around ~2000 days after the end of their outbursts. Furthermore, they both showed an even more unexpected rise of ~3 eV in temperature (over a time period of ~500-2000 days) after this steep decay. This rise was significant at the 2.4{\sigma} and 8.5{\sigma} level for XTE J1701-462 and EXO 0748-676, respectively. The physical explanation for such behaviour is unknown and cannot be straightforwardly be explained within the cooling hypothesis. In addition, this observed evolution cannot be well explained by low-level accretion either without invoking many assumptions. We investigate the potential pathways in the theoretical heating and cooling models that could reproduce this unusual behaviour, which so far has been observed in two crust-cooling sources. Such a temperature increase has not been observed in the other NS crust-cooling sources at similarly late times, although it cannot be excluded that this might be a result of the inadequate sampling obtained at such late times.Comment: accepted for publication by A&A letter
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