85 research outputs found

    Improving market outcomes: A qualitative assessment of the Greek dairy supply chain

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    ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗThis study provides a qualitatative assessment of the overall outcomes of the dairy supply chain in Greece. Based on the framework of the Taskforce for Agricultural Markets, a questionnaire survey with in-depth interviews was conducted to farmers, industries and supermarkets in Greece in order to gain knowledge about trading practices, market transparency, risk management, contracts, access to finance and the role of Producer Organizations. The analysis did not reveal significant unfair trading practices and showed positive prospects for the overall supply chain

    The ratio m_c/m_s with Wilson fermions

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    We determine the quark mass ratio m_c/m_s on the lattice, using Wilson-type fermions. Configurations with N_f=2 dynamical clover-improved fermions by the QCDSF collaboration are used, which were made available through the ILDG. In the valence sector we use a sophisticated, mass-independently O(a)-improved Wilson-type action with small cut-off effects even in the charm mass region. After an extrapolation to the physical pion mass, to zero lattice spacing and to infinite box volume, we find m_c/m_s=11.27(30)(26).Comment: 7 pages, 1 figure; v2: more statistics, improved analysis and presentation, 1 reference adde

    Delta-baryon electromagnetic form factors in lattice QCD

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    We develop techniques to calculate the four Delta electromagnetic form factors using lattice QCD, with particular emphasis on the sub-dominant electric quadrupole form factor that probes deformation of the Delta. Results are presented for pion masses down to approximately 350 MeV for three cases: quenched QCD, two flavors of dynamical Wilson quarks, and three flavors of quarks described by a mixed action combining domain wall valence quarks and dynamical staggered sea quarks. The magnetic moment of the Delta is chirally extrapolated to the physical point and the Delta charge density distributions are discussed.Comment: 4 pages, 5 figure

    Quark flavor decomposition of the nucleon axial form factors

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    We present results on the isoscalar form factors including the disconnected contributions, as well as on the strange and charm quark form factors. Using previous results on the isovector form factors, we determine the flavor decomposition of the nucleon axial form factors. These are computed using an ensemble of Nf=2+1+1N_f=2+1+1 twisted mass fermions simulated with physical values of quark masses. We investigate the SU(3) flavor symmetry and show that there is up to 10\% breaking for the axial and up to 50\% for the induced pseudoscalar form factors. By fitting the Q2Q^2-dependence, we determined the corresponding root mean square radii. The pseudoscalar coupling of the η\eta meson and the nucleon is found to be gηNN=3.7(1.0)(0.7)g_{\eta NN}=3.7(1.0)(0.7), and the Goldberger-Treiman discrepancy for the octet combination about 50\%

    Complete flavor decomposition of the spin and momentum fraction of the proton using lattice QCD simulations at physical pion mass

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    We evaluate the gluon and quark contributions to the spin of the proton using an ensemble of gauge configuration generated at physical pion mass. We compute all valence and sea quark contributions to high accuracy. We perform a non-perturbative renormalization for both quark and gluon matrix elements. We find that the contribution of the up, down, strange and charm quarks to the proton intrinsic spin is 12q=u,d,s,cΔΣq+=0.191(15)\frac{1}{2}\sum_{q=u,d,s,c}\Delta\Sigma^{q^+}=0.191(15) and to the total spin q=u,d,s,cJq+=0.285(45)\sum_{q=u,d,s,c}J^{q^+}=0.285(45). The gluon contribution to the spin is Jg=0.187(46)J^g=0.187(46) yielding J=Jq+Jg=0.473(71)J=J^q+J^g=0.473(71) confirming the spin sum. The momentum fraction carried by quarks in the proton is found to be 0.618(60)0.618(60) and by gluons 0.427(92)0.427(92), the sum of which gives 1.045(118)1.045(118) confirming the momentum sum rule. All scale and scheme dependent quantities are given in the MS\mathrm{ \overline{MS}} scheme at 2 GeV

    The nucleon to Delta electromagnetic transition form factors in lattice QCD

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    The electromagnetic nucleon to Delta transition form factors are evaluated using two degenerate flavors of dynamical Wilson fermions and using dynamical sea staggered fermions with domain wall valence quarks. The two subdominant quadrupole form factors are evaluated for the first time in full QCD to sufficient accuracy to exclude a zero value, which is taken as a signal for deformation in the nucleon-Delta system. For the Coulomb quadrupole form factor the unquenched results show deviations from the quenched results at low q^2 bringing dynamical lattice results closer to experiment, thereby confirming the importance of pion cloud contributions on this quantity.Comment: 15 pages, 8 Figure

    Nucleon axial, tensor and scalar charges and σ\sigma-terms in lattice QCD

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    We determine the nucleon axial, scalar and tensor charges within lattice Quantum Chromodynamics including all contributions from valence and sea quarks. We analyze three gauge ensembles simulated within the twisted mass formulation at approximately physical value of the pion mass. Two of these ensembles are simulated with two dynamical light quarks and lattice spacing a=0.094a=0.094~fm and the third with a=0.08a=0.08~fm includes in addition the strange and charm quarks in the sea. After comparing the results among these three ensembles, we quote as final values our most accurate analysis using the latter ensemble. For the nucleon isovector axial charge we find 1.286(23)1.286(23) in agreement with the experimental value. We provide the flavor decomposition of the intrinsic spin 12ΔΣq\frac{1}{2}\Delta\Sigma^q carried by quarks in the nucleon obtaining for the up, down, strange and charm quarks 12ΔΣu=0.431(8)\frac{1}{2}\Delta\Sigma^{u}=0.431(8), 12ΔΣd=0.212(8)\frac{1}{2}\Delta\Sigma^{d}=-0.212(8), 12ΔΣs=0.023(4)\frac{1}{2}\Delta\Sigma^{s}=-0.023(4) and 12ΔΣc=0.005(2)\frac{1}{2}\Delta\Sigma^{c}=-0.005(2), respectively. The corresponding values of the tensor and scalar charges for each quark flavor are also evaluated providing valuable input for experimental searches for beyond the standard model physics. In addition, we extract the nucleon σ\sigma-terms and find for the light quark content σπN=41.6(3.8)\sigma_{\pi N}=41.6(3.8)~MeV and for the strange σs=45.6(6.2)\sigma_{s}=45.6(6.2)~MeV. The y-parameter that is used in phenomenological studies we find y=0.078(7)y=0.078(7).Comment: Expanded version as accepted in Phys. Rev. D.20 pages and 20 figure

    Hepatic steatosis in patients with acromegaly

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    Objective Comorbid NAFLD is increasingly being diagnosed in patients with diabetes and nondiabetic endocrinopathies. The aim of this study was to assess hepatic steatosis noninvasively by transient elastography in patients with acromegaly. Design A cross‐sectional study including 22 patients with acromegaly. Methods Hepatic steatosis was quantified using controlled attenuation parameter (CAP) during elastography. Anthropometric measurements were obtained, serum liver function tests and lipid and hormone profiles were measured, and prosteatogenic gene variants were genotyped using standard assays. Results In total, 41% of patients were women (mean age 60 ± 14.7 years, mean BMI 31.2 ± 4.6 kg/m2). Hepatic steatosis, as defined by CAP > 248 dB/m, was present in 66% of patients. Five (45%) of the patients with hepatic steatosis also had fibrosis, and one presented with cirrhosis. Nine patients were carriers of the PNPLA3 p.I148M prosteatogenic [M] risk allele, eight of whom were heterozygotes. CAP values were significantly (P = .045) higher in these patients and corresponded to advanced steatosis, as compared to patients with the wild‐type genotype, who demonstrated CAP values consistent with mild steatosis (311 ± 33 dB/m. vs 254 ± 62 dB/m). CAP values did not differ significantly in carriers of distinct TM6SF2 and MBOAT7 genotypes; however, carriers of the risk alleles displayed higher CAP as compared to wild‐type patients. Conclusions This study shows that in patients with acromegaly, carriers of the PNPLA3 susceptibility allele are at risk of developing hepatic steatosis, as assessed by CAP. Comorbid NAFLD might compound prognosis in such patients; thus, further research into the pathomechanisms and treatment of NAFLD in acromegaly is warranted
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