9,390 research outputs found
Bethe-Salpeter equations: mesons beyond the rainbow-ladder truncation
We investigate masses of light mesons from a coupled system of
Dyson--Schwinger (DSE) and Bethe--Salpeter equations (BSE), taking into account
dominant non-Abelian, sub-leading Abelian, and dominant pion cloud
contributions to the dressed quark-gluon vertex. The axial-vector
Ward-Takahashi identity preserving Bethe-Salpeter kernel is constructed and the
spectrum of light mesons calculated. Our model goes significantly beyond the
rainbow-ladder. We find that sub-leading Abelian corrections are further
dynamically suppressed, and that our results supersede early qualitative
predictions from simple truncation schemes.Comment: 4 pages, 3 figures, 1 table. Talk given at the 5-th Int. Conf. on
Quarks and Nuclear Physics, Beijing, September 21-26,200
Enriched Lawvere Theories for Operational Semantics
Enriched Lawvere theories are a generalization of Lawvere theories that allow
us to describe the operational semantics of formal systems. For example, a
graph enriched Lawvere theory describes structures that have a graph of
operations of each arity, where the vertices are operations and the edges are
rewrites between operations. Enriched theories can be used to equip systems
with operational semantics, and maps between enriching categories can serve to
translate between different forms of operational and denotational semantics.
The Grothendieck construction lets us study all models of all enriched theories
in all contexts in a single category. We illustrate these ideas with the
SKI-combinator calculus, a variable-free version of the lambda calculus.Comment: In Proceedings ACT 2019, arXiv:2009.0633
Examination of Methylation Sites for Forensic Age Determination from Semen
Methylation Sensitive High-Resolution Melt (MS-HRM) is based on quantitating the melt curve from an experimental sample against a standard of known methylation levels. Whereas most applications of age prediction using methylation markers are based upon pyrosequencing or SNaPshot technologies, these analysis methods are both cost and instrumentation prohibitive. This study sought to use to the varied methylation status of the ELOVL2 and FHL2 alleles, both having known correlation with age (Hamano et. al.), in a labor and time efficient manner to develop an age prediction model. A non-linear regression and standard curve was compiled from the methylation status in a sample (n=7) of extracted semen samples and compared to chronological age. The methylation status of ELVOL2 and FHL2 from each sample was obtained, with the conclusion that no correlation in methylation percentage and biological age existed for this sample of individuals aged 20-33. The principal objective of this study, to expand the application of MS-HRM age prediction from blood to other body fluids, will need further testing using larger sample sizes and broader age ranges prior to application in forensic casework.https://scholarscompass.vcu.edu/uresposters/1281/thumbnail.jp
Alterations in histamine responses between juvenile and adult urinary bladder urothelium, lamina propria and detrusor tissues
The five primary prostaglandins stimulate contractions and phasic activity of the urinary bladder urothelium, lamina propria and detrusor
Mass spectra and Regge trajectories of light mesons in the Bethe-Salpeter approach
We extend the calculation of relativistic bound-states of a fermion
anti-fermion pair in the Bethe-Salpeter formalism to the case of total angular
momentum . Together with results for this allows for the
investigation of Regge trajectories in this approach. We exemplify such a study
for ground and excited states of light unflavored mesons as well as strange
mesons within the rainbow-ladder approximation. For the - and
-meson we find a linear Regge trajectory within numerical accuracy.
Discrepancies with experiment in other channels highlight the need to go beyond
rainbow-ladder and to consider effects such as state mixing and more
sophisticated quark-antiquark interaction kernels.Comment: 11 pages, 8 figures, 2 tables. Minor typos corrected; accepted in
EPJ
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