184 research outputs found

    Vibrations and Berry Phases of Charged Buckminsterfullerene

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    A simple model of electron-vibron interactions in buckminsterfullerene ions is solved semiclassically. Electronic degeneracies of C60_{60}n^{n-} induce dynamical Jahn-Teller distortions, which are unimodal for n ⁣ ⁣3n\!\ne\!3 and bimodal for n ⁣= ⁣3n\!=\!3. The quantization of motion along the Jahn-Teller manifold leads to a symmetric-top rotator Hamiltonian. I find Molecular Aharonov-Bohm effects where electronic Berry phases determine the vibrational spectra, zero point fluctuations, and electrons' pair binding energies. The latter are relevant to superconductivity in alkali-fullerenes.Comment: Latex 11 pages. IIT-00

    Genetic variation at MECOM, TERT, JAK2 and HBS1L-MYB predisposes to myeloproliferative neoplasms

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    Clonal proliferation in myeloproliferative neoplasms (MPN) is driven by somatic mutations in JAK2, CALR or MPL, but the contribution of inherited factors is poorly characterized. Using a three-stage genome-wide association study of 3,437 MPN cases and 10,083 controls, we identify two SNPs with genome-wide significance in JAK2V617F-negative MPN: rs12339666 (JAK2; meta-analysis P=1.27 × 10−10) and rs2201862 (MECOM; meta-analysis P=1.96 × 10−9). Two additional SNPs, rs2736100 (TERT) and rs9376092 (HBS1L/MYB), achieve genome-wide significance when including JAK2V617F-positive cases. rs9376092 has a stronger effect in JAK2V617F-negative cases with CALR and/or MPL mutations (Breslow–Day P=4.5 × 10−7), whereas in JAK2V617F-positive cases rs9376092 associates with essential thrombocythemia (ET) rather than polycythemia vera (allelic χ2 P=7.3 × 10−7). Reduced MYB expression, previously linked to development of an ET-like disease in model systems, associates with rs9376092 in normal myeloid cells. These findings demonstrate that multiple germline variants predispose to MPN and link constitutional differences in MYB expression to disease phenotype

    Political Radicalization as a Communication Process

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    Based on data taken from 412 adult education students in Montreal, Quebec, Canada, this research attempts to show that attitudes toward French Canadian Separatism by the sample members can be accounted for by differentiaf communication processes. Results show that attitudes held by sample members are well explained (R2 = .64) by a weighted average of the information they received from interpersonal and media sources. The resultant attitude shows substantial effects on behaviors related to separatism for the same respondents.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67215/2/10.1177_009365027400100301.pd

    Search for the doubly heavy baryon Ξbc+\it{\Xi}_{bc}^{+} decaying to J/ψΞc+J/\it{\psi} \it{\Xi}_{c}^{+}

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    A first search for the Ξbc+J/ψΞc+\it{\Xi}_{bc}^{+}\to J/\it{\psi}\it{\Xi}_{c}^{+} decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9fb19\,\mathrm{fb}^{-1} recorded at centre-of-mass energies of 7, 8, and 13TeV13\mathrm{\,Te\kern -0.1em V}. Two peaking structures are seen with a local (global) significance of 4.3(2.8)4.3\,(2.8) and 4.1(2.4)4.1\,(2.4) standard deviations at masses of 6571MeV ⁣/c26571\,\mathrm{Me\kern -0.1em V\!/}c^2 and 6694MeV ⁣/c26694\,\mathrm{Me\kern -0.1em V\!/}c^2, respectively. Upper limits are set on the Ξbc+\it{\Xi}_{bc}^{+} baryon production cross-section times the branching fraction relative to that of the Bc+J/ψDs+B_{c}^{+}\to J/\it{\psi} D_{s}^{+} decay at centre-of-mass energies of 8 and 13TeV13\mathrm{\,Te\kern -0.1em V}, in the Ξbc+\it{\Xi}_{bc}^{+} and in the Bc+B_{c}^{+} rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to 20GeV ⁣/c20\,\mathrm{Ge\kern -0.1em V\!/}c, respectively. Upper limits are presented as a function of the Ξbc+\it{\Xi}_{bc}^{+} mass and lifetime.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-005.html (LHCb public pages
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