1,490 research outputs found

    Widespread occurrence of Mycobacterium tuberculosis DNA from 18th-19th century Hungarians

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    A large number (265) of burials from 1731-1838 were discovered in sealed crypts of the Dominican Church, Vac, Hungary in 1994. Many bodies were naturally mummified, so that both soft tissues and bones were available. Contemporary archives enabled the determination of age at death, and the identification of family groups. In some cases, symptoms before death were described and, occasionally, occupation. Initial radiological examination of a small number of individuals had indicated calcified lung lesions and demonstrable acid-fast bacteria suggestive of tuberculosis infection. Tuberculosis was endemic in 18th-19th century Europe, so human remains should contain detectable Mycobacterium tuberculosis complex (MTB) DNA, enabling comparisons with modern isolates. Therefore, a comprehensive examination of 168 individuals for the presence of MTB DNA was undertaken. Specific DNA amplification methods for MTB showed that 55% of individuals were positive and that the incidence varied according to age at death and sampling site in the body. Radiographs were obtained from 27 individuals and revealed an association between gross pathology and the presence of MTB DNA. There was an inverse relationship between PCR positivity and MTB target sequence size. In some cases, the preservation of MTB DNA was excellent, and several target gene sequences could be detected from the same sample. This information, combined with MTB DNA sequencing data and molecular typing techniques, will enable us to study the past epidemiology of TB infection, and extends the timeframe for studying changes in molecular fingerprints. Am J Phys Anthropol 120:144-152, 2003. (C) 2003 Wiley-Liss, Inc

    Constraints on the variability of quark masses from nuclear binding

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    Based on recent work on nuclear binding, we update and extend the anthropic constraints on the light quark masses, with results that are more tightly constrained than previously obtained. We find that heavy nuclei would fall apart (because the attractive nuclear central potential becomes too weak) if the sum of the light quark masses m_u+m_d would exceed their physical values by 64% (at 95% confidence level). We summarize the anthropic constraints that follow from requiring the existence both of heavy atoms and of hydrogen. With the additional assumption that the quark Yukawa couplings do not vary, these constraints provide a remarkably tight anthropic window for the Higgs vacuum expectation value: 0.39 < v/v_physical < 1.64.Comment: 21 pages, 7 figure

    Lifetime Differences in Heavy Mesons With Time Independent Measurements

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    Heavy meson pairs produced in the decays of heavy quarkonium resonances at e+ e- machines (beauty and tau-charm factories) have the useful property that the two mesons are in the CP-correlated states. By tagging one of the mesons as a CP eigenstate, a lifetime difference of heavy neutral meson mass eigenstates width difference may be determined by measuring the leptonic branching ratio of the other meson. We discuss the use of this and related methods both in the case where time dependent mixing is small and when it is significant. We consider the impact of possible CP-violating effects and present the complete results for CP-entangled decay rates with CP-violation taken into account.Comment: 14 pages, 0 figures; 2 references added, results unchange

    Quantum power correction to the Newton law

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    We have found the graviton contribution to the one-loop quantum correction to the Newton law. This correction results in interaction decreasing with distance as 1/r^3 and is dominated numerically by the graviton contribution. The previous calculations of this contribution to the discussed effect are demonstrated to be incorrect.Comment: 10 pages, 5 figures; numerical error corrected, few references adde

    On the Ultraviolet Behaviour of Newton's constant

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    We clarify a point concerning the ultraviolet behaviour of the Quantum Field Theory of gravity, under the assumption of the existence of an ultraviolet Fixed Point. We explain why Newton's constant should to scale like the inverse of the square of the cutoff, even though it is technically inessential. As a consequence of this behaviour, the existence of an UV Fixed Point would seem to imply that gravity has a built-in UV cutoff when described in Planck units, but not necessarily in other units.Comment: 8 pages; CQG class; minor changes and rearrangement

    Can one see the number of colors in eta, eta-prime --> pi^+ pi^- gamma?

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    We investigate the decays eta, eta-prime --> pi^+ pi^- gamma up to next-to-leading order in the framework of the combined 1/N_c and chiral expansions. Counter terms of unnatural parity at next-to-leading order with unknown couplings are important to acommodate the results both to the experimental decay width and the photon spectrum. The presence of these coefficients does not allow for a determination of the number of colors from these decays.Comment: 8 pages, 2 figure

    Detection and characterization of Mycobacterium tuberculosis DNA in 18th Century Hungarians with pulmonary and extra-pulmonary tuberculosis

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    Skeletal and naturally mummified tissues from a previously archived group of 18th century Hungarian remains were examined for the presence of Mycobacterium tuberculosis complex (MTB) DNA, using specific nested PCR for the IS6110 locus. Paleopathological changes in bones and from radiographs were noted in a minority of cases. Overall, specimens from 157/232 (67.7 %) of individuals proved positive, ranging from 20/43 (46.5 %) in children, 26/29 in middle-age (89.7 %) and 32/46 individuals aged 65-95 years (69.6 %). Single samples gave a positive result in 67/120 of cases (55.8 %). Most were ribs where the surface adjacent to lungs and pleura was sampled. When multiple sites were examined, 73/93 (78.5 %) individuals were positive; most of these had MTB only in the pulmonary region but 26 had disseminated disease (35.6 %) and 12 (16.4 %) had extra-pulmonary disease only. To distinguish M. tuberculosis from Mycobacterium bovis, well-preserved positive samples were examined for several additional genetic loci including the TbD1 deletion – characteristic of modern European strains of M. tuberculosis, and spoligotyped. No evidence other than of human M. tuberculosis was found, but different strains were detected. Tuberculosis was widespread in this community and whilst some individuals succumbed early in life, the majority co-existed with the infection. Therefore, this study may lead to the identification of host alleles and MTB strains associated with active and latent disease

    CP Violation in D0−D0‾D^0-\overline{D^0}Mixing

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    The existence of D0−D0‾D^0-\overline{D^0} mixing at a detectable level requires new physics, which effectively yields a Δc=2\Delta c = 2 superweak interaction. In general this interaction may involve significant CP violation. For small values of the mixing it may be much easier to detect the CP-violating part of the mixing than the CP-conserving part.Comment: 3 pages, latex, no figure
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