The Goldberger-Treiman Discrepancy

The Golberger- Treiman discrepancy is related to the asymptotic behaviour of the pionic form factor of the nucleon obtained from baryonic QCD sum rules. The result is .015<=Delta_{GT}<=.022Comment: References updated and minor correction

Up and down quark masses from Finite Energy QCD sum rules to five loops

The up and down quark masses are determined from an optimized QCD Finite Energy Sum Rule (FESR) involving the correlator of axial-vector divergences, to five loop order in Perturbative QCD (PQCD), and including leading non-perturbative QCD and higher order quark mass corrections. This FESR is designed to reduce considerably the systematic uncertainties arising from the (unmeasured) hadronic resonance sector, which in this framework contributes less than 3-4% to the quark mass. This is achieved by introducing an integration kernel in the form of a second degree polynomial, restricted to vanish at the peak of the two lowest lying resonances. The driving hadronic contribution is then the pion pole, with parameters well known from experiment. The determination is done in the framework of Contour Improved Perturbation Theory (CIPT), which exhibits a very good convergence, leading to a remarkably stable result in the unusually wide window $s_0 = 1.0 - 4.0 {GeV}^2$, where $s_0$ is the radius of the integration contour in the complex energy (squared) plane. The results are: $m_u(Q= 2 {GeV}) = 2.9 \pm 0.2$ MeV, $m_d(Q= 2 {GeV}) = 5.3 \pm 0.4$ MeV, and $(m_u + m_d)/2 = 4.1 \pm 0.2$ Mev (at a scale Q=2 GeV).Comment: Additional references to lattice QCD results have been adde

The impact of conventional and nonconventional inhalants on children and adolescents

AimInhalant abuse in the adolescent population is a growing concern for care givers, communities, physicians, and medical providers. The aim of this article is to provide a review of the literature about this new challenge. In addition, it raises awareness about recent health policy rulings.MethodsReview of the literature was done.ResultsIn this review article, the prevalence of different modes of inhalant use and abuse in children and young adults and their potential health implications will be examined: Cigarettes, ENDS (E Cigarettes), Hookah, Marijuana, and Huffing. Additionally, marketing and advertising tactics will be reviewed to understand how they target this population. A review of current health policy recommendations from the FDA, American Thoracic Society, and the American Academy of Pediatrics will also be discussed.ConclusionThe rapid rise in e‐cigarette and hookah use in school aged children should trigger a call to action in the medical and public health communities. Health policy recommendations need to be made to reduce the level of adolescent substance abuse.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142898/1/ppul23836_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142898/2/ppul23836.pd

Discriminating quantum gravity models by gravitational decoherence

Several phenomenological approaches to quantum gravity assume the existence of a minimal measurable length and/or a maximum measurable momentum near the Planck scale. When embedded into the framework of quantum mechanics, such constraints induce a modification of the canonical commutation relations and thus a generalization of the Heisenberg uncertainty relations, commonly referred to as generalized uncertainty principle (GUP). Different models of quantum gravity imply different forms of the GUP. For instance, in the framework of string theory the GUP is quadratic in the momentum operator, while in the context of doubly special relativity it includes an additional linear dependence. Among the possible physical consequences, it was recently shown that the quadratic GUP induces a universal decoherence mechanism, provided one assumes a foamy structure of quantum spacetime close to the Planck length. Along this line, in the present work we investigate the gravitational decoherence associated to the linear-quadratic GUP and we compare it with the one associated to the quadratic GUP. We find that, despite their similarities, the two generalizations of the Heisenberg uncertainty principle yield decoherence times that are completely uncorrelated and significantly distinct. Motivated by this result, we introduce a theoretical and experimental scheme based on cavity optomechanics to measure the different time evolution of nonlocal quantum correlations corresponding to the two aforementioned decoherence mechanisms. We find that the deviation between the two predictions occurs on time scales that are macroscopic and thus potentially amenable to experimental verification. This scenario provides a possible setting to discriminate between different forms of the GUP and therefore different models of quantum gravity.Comment: v1: 11 pages, 2 figures; v2: 11 pages, 2 figures, title, abstract and references slightly edited and updated for better clarity; no change in the physics; v3: 14 pages, 3 figures, title changed, new section and clarifications adde

Symmetry of standing waves generated by a point defect in epitaxial graphene

Using scanning tunneling microscopy (STM) and Fourier Transform STM (FT-STM), we have studied a point defect in an epitaxial graphene sample grown on silicon carbide substrate. This analysis allows us to extract the quasiparticle energy dispersion, and to give a first experimental proof of the validity of Fermi liquid theory in graphene for a wide range of energies from -800 meV to +800 meV. We also find evidence of a strong threefold anisotropy in the standing waves generated by the defect. We discuss possible relations between this anisotropy, the chirality of the electrons, and the asymmetry between graphene's two sublattices. All experimental measurements are compared and related to theoretical T-matrix calculations.Comment: 4 pages, 4 figure

Optical Properties of Wide Band Gap Indium Sulphide Thin Films Obtained by Physical Vapor Deposition

Thin films of indium sulphide containing oxygen have been synthesized following a dry physical process. The constituents are deposited by thermal evaporation on glass substrates and then annealed under argon flow. Polycrystalline β-In2S3 containing oxygen thin films are obtained as soon as the temperature of annealing is between 623 and 723 K. In this paper, these β-In2S3 thin films have optically been studied. The optical band gap is direct. Its value is not dependent on the temperature of annealing. It is about 2.8 eV, which is higher than that of β-In2S3 single crystal. This high value is related to the presence of oxygen in the films. The extinction coefficient k and the refractive index n of the films have also been found independent of the annealing temperature. These optical properties make the films studied good candidates to be substituted to CdS in Cu(In,Ga)Se2 based solar cells

Down-Regulation of Platelet Imidazoline-1-Binding Sites after Bupropion Treatment

An elevation of I1 (imidazoline-1)-binding sites on platelets may be a state marker for depression. Herein, platelet I1 sites were compared in two groups of unipolar depressed patients given different regimens of bupropion treatment : Regimen 1 (n=13 titrated up to 300 mg}d by week 4 and held constant until week 6) ; Regimen 2 (n=15 titrated up to 300 mg}d by week 2, to 450 mg}d by week 6, and held constant until week 8). Platelet I1 sites were quantified by p-[125I]iodoclonidine binding (0.5–15 nm) and displaced by moxonidine under a saturating concentration of norepinephrine to mask α2-adrenoceptors. I1 Bmax values were confirmed to be high at pretreatment in depressed patients (n=28) compared to healthy control subjects (n=18 ; p=0.02). Highest Bmax values at pretreatment were found in patients who responded worst to treatment. More than two-thirds of patients recovered from depression (69 and 80% in Regimens 1 and 2, respectively) after treatment. Dose and/or time of exposure to bupropion were relevant variables since (1) only Regimen 2 led to platelet I1 down-regulation and (2) the extent of down-regulation correlated with plasma concentrations of bupropion. The data suggest a dissociation exists between I1 down-regulation and therapeutic response, or else platelet I1 down-regulation lags behind clinical antidepressant response before becoming measurable