32 research outputs found

    Universal light quark mass dependence and heavy-light meson spectroscopy

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    Clean predictions are presented for all the spin-averaged heavy-light meson spectroscopies. A new symmetry is identified wherein the energy eigenstates have a universal dependence on both the light and heavy quark masses. This universality is used in an efficient analysis of these mesons within the QCD string/flux tube picture. Unique predictions for all the D, D_s, B, and B_s type mesons in terms of just four measured quantities.Comment: REVTeX4, 6 pages, 9 eps figure

    Reduction of the QCD string to a time component vector potential

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    We demonstrate the equivalence of the relativistic flux tube model of mesons to a simple potential model in the regime of large radial excitation. We make no restriction on the quark masses; either quark may have a zero or finite mass. Our primary result shows that for fixed angular momentum and large radial excitation, the flux tube/QCD string meson with a short-range Coulomb interaction is described by a spinless Salpeter equation with a time component vector potential V(r) = ar - k/r.Comment: RevTeX4, 10 pages, 3 eps figure

    A major locus confers triclabendazole resistance in Fasciola hepatica and shows dominant inheritance

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    Fasciola hepatica infection is responsible for substantial economic losses in livestock worldwide and poses a threat to human health in endemic areas. The mainstay of control in livestock and the only drug licenced for use in humans is triclabendazole (TCBZ). TCBZ resistance has been reported on every continent and threatens effective control of fasciolosis in many parts of the world. To date, understanding the genetic mechanisms underlying TCBZ resistance has been limited to studies of candidate genes, based on assumptions of their role in drug action. Taking an alternative approach, we combined a genetic cross with whole-genome sequencing to localise a ~3.2Mbp locus within the 1.2Gbp F. hepatica genome that confers TCBZ resistance. We validated this locus independently using bulk segregant analysis of F. hepatica populations and showed that it is the target of drug selection in the field. We genotyped individual parasites and tracked segregation and reassortment of SNPs to show that TCBZ resistance exhibits Mendelian inheritance and is conferred by a dominant allele. We defined gene content within this locus to pinpoint genes involved in membrane transport, (e.g. ATP-binding cassette family B, ABCB1), transmembrane signalling and signal transduction (e.g. GTP-Ras-adenylyl cyclase and EGF-like protein), DNA/RNA binding and transcriptional regulation (e.g. SANT/Myb-like DNA-binding domain protein) and drug storage and sequestration (e.g. fatty acid binding protein, FABP) as prime candidates for conferring TCBZ resistance. This study constitutes the first experimental cross and genome-wide approach for any heritable trait in F. hepatica and is key to understanding the evolution of drug resistance in Fasciola spp. to inform deployment of efficacious anthelmintic treatments in the field

    Hadronic Regge Trajectories: Problems and Approaches

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    We scrutinized hadronic Regge trajectories in a framework of two different models --- string and potential. Our results are compared with broad spectrum of existing theoretical quark models and all experimental data from PDG98. It was recognized that Regge trajectories for mesons and baryons are not straight and parallel lines in general in the current resonance region both experimentally and theoretically, but very often have appreciable curvature, which is flavor-dependent. For a set of baryon Regge trajectories this fact is well described in the considered potential model. The standard string models predict linear trajectories at high angular momenta J with some form of nonlinearity at low J.Comment: 15 pages, 9 figures, LaTe

    A major locus confers triclabendazole resistance in Fasciola hepatica and shows dominant inheritance

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    From PLOS via Jisc Publications RouterHistory: received 2022-10-02, accepted 2022-12-22, collection 2023-01, epub 2023-01-26Acknowledgements: We are grateful for the advice and sequencing services provided by staff within the Centre for Genomic Research, University of Liverpool. A list of ABC transporter genes was provided courtesy of Professor Aaron Maule, Dr Erin McCammick and Dr Nathan Clarke, Queen’s University Belfast. We would like to acknowledge the support of the Animal and Plant Health Agency, APHA. We would like to extend our gratitude to the farmers who provided faecal samples from sheep, and the veterinarians in private practice who collected these for us. We would like to acknowledge the help of Ms Alice Balard, Mrs Catherine Hartley, Mr Nigel Jones, Mrs Helen Smith, and Professor Rob Smith for their assistance with maintenance of snail colonies, animal care and sample collection within the Institute of Infection, Veterinary and Ecological Sciences at the University of Liverpool.Publication status: PublishedFunder: Biotechnology and Biological Sciences Research Council; funder-id: http://dx.doi.org/10.13039/501100000268; Grant(s): BB/1002480/1Funder: Biotechnology and Biological Sciences Research Council; funder-id: http://dx.doi.org/10.13039/501100000268; Grant(s): BB/P001912/1Fasciola hepatica infection is responsible for substantial economic losses in livestock worldwide and poses a threat to human health in endemic areas. The mainstay of control in livestock and the only drug licenced for use in humans is triclabendazole (TCBZ). TCBZ resistance has been reported on every continent and threatens effective control of fasciolosis in many parts of the world. To date, understanding the genetic mechanisms underlying TCBZ resistance has been limited to studies of candidate genes, based on assumptions of their role in drug action. Taking an alternative approach, we combined a genetic cross with whole-genome sequencing to localise a ~3.2Mbp locus within the 1.2Gbp F. hepatica genome that confers TCBZ resistance. We validated this locus independently using bulk segregant analysis of F. hepatica populations and showed that it is the target of drug selection in the field. We genotyped individual parasites and tracked segregation and reassortment of SNPs to show that TCBZ resistance exhibits Mendelian inheritance and is conferred by a dominant allele. We defined gene content within this locus to pinpoint genes involved in membrane transport, (e.g. ATP-binding cassette family B, ABCB1), transmembrane signalling and signal transduction (e.g. GTP-Ras-adenylyl cyclase and EGF-like protein), DNA/RNA binding and transcriptional regulation (e.g. SANT/Myb-like DNA-binding domain protein) and drug storage and sequestration (e.g. fatty acid binding protein, FABP) as prime candidates for conferring TCBZ resistance. This study constitutes the first experimental cross and genome-wide approach for any heritable trait in F. hepatica and is key to understanding the evolution of drug resistance in Fasciola spp. to inform deployment of efficacious anthelmintic treatments in the field

    Glueball spectrum and the Pomeron in the Wilson loop approach

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    Using a nonperturbative method based on asymptotic behaviour of Wilson loops we calculate masses of glueballs and corresponding Regge-trajectories. The only input is string tension fixed by meson Regge slope, while perturbative contributions to spin splittings are defined by standard alpha_s values. The masses of lowest glueball states are in a perfect agreement with lattice results. The leading glueball trajectory which is associated with Pomeron is discussed in details and its mixing with f and f' trajectories is taken into account.Comment: LaTeX2e, 49 pages, 2 figure

    QCD string in light-light and heavy-light mesons

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    The spectra of light-light and heavy-light mesons are calculated within the framework of the QCD string model, which is derived from QCD in the Wilson loop approach. Special attention is payed to the proper string dynamics that allows us to reproduce the straight-line Regge trajectories with the inverse slope being 2\pi\sigma for light-light and twice as small for heavy-light mesons. We use the model of the rotating QCD string with quarks at the ends to calculate the masses of several light-light mesons lying on the lowest Regge trajectories and compare them with the experimental data as well as with the predictions of other models. The masses of several low-lying orbitally and radially excited heavy--light states in the D, D_s, B, and B_s meson spectra are calculated in the einbein (auxiliary) field approach, which has proven to be rather accurate in various calculations for relativistic systems. The results for the spectra are compared with the experimental and recent lattice data. It is demonstrated that an account of the proper string dynamics encoded in the so-called string correction to the interquark interaction leads to an extra negative contribution to the masses of orbitally excited states that resolves the problem of the identification of the D(2637) state recently claimed by the DELPHI Collaboration. For the heavy-light system we extract the constants \bar\Lambda, \lambda_1, and \lambda_2 used in Heavy Quark Effective Theory (HQET) and find good agreement with the results of other approaches.Comment: RevTeX, 42 pages, 7 tables, 7 EPS figures, uses epsfig.sty, typos corrected, to appear in Phys.Rev.

    Heavy Quarkonia: Wilson Area Law, Stochastic Vacuum Model and Dual QCD

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    The QQˉQ \bar{Q} semirelativistic interaction in QCD can be simply expressed in terms of the Wilson loop and its functional derivatives. In this approach we present the QQˉQ \bar{Q} potential up to order 1/m21/m^2 using the expressions for the Wilson loop given by the Wilson Minimal Area Law (MAL), the Stochastic Vacuum Model (SVM) and Dual QCD (DQCD). We confirm the original results given in the different frameworks and obtain new contributions. In particular we calculate up to order 1/m21/m^2 the complete velocity dependent potential in the SVM. This allows us to show that the MAL model is entirely contained in the SVM. We compare and discuss also the SVM and the DQCD potentials. It turns out that in these two very different models the spin-orbit potentials show up the same leading non-perturbative contributions and 1/r corrections in the long-range limit.Comment: 29 pages, revtex, 1 figure(fig1.ps); replaced with the last version that will appear in Phys. Rev. D (1March 1997); few misprints correcte

    The physics of non-crystalline solids

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