Calculation of the Hadronic Vacuum Polarization Contribution to the Muon Anomalous Magnetic Moment.

We present a first-principles lattice QCD+QED calculation at physical pion mass of the leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment. The total contribution of up, down, strange, and charm quarks including QED and strong isospin breaking effects is a_{µ}^{HVP LO}=715.4(18.7)×10^{-10}. By supplementing lattice data for very short and long distances with R-ratio data, we significantly improve the precision to a_{µ}^{HVP LO}=692.5(2.7)×10^{-10}. This is the currently most precise determination of a_{µ}^{HVP LO}.

Up and Down Quark Masses and Corrections to Dashen's Theorem from Lattice QCD and Quenched QED.

In a previous Letter [Borsanyi et al., Phys. Rev. Lett. 111, 252001 (2013)] we determined the isospin mass splittings of the baryon octet from a lattice calculation based on N_{f}=2+1 QCD simulations to which QED effects have been added in a partially quenched setup. Using the same data we determine here the corrections to Dashen's theorem and the individual up and down quark masses. Our ensembles include 5 lattice spacings down to 0.054 fm, lattice sizes up to 6 fm, and average up-down quark masses all the way down to their physical value. For the parameter which quantifies violations to Dashen's theorem, we obtain ϵ=0.73(2)(5)(17), where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light quark masses we obtain, m_{u}=2.27(6)(5)(4) and m_{d}=4.67(6)(5)(4) MeV in the modified minimal subtraction scheme at 2 GeV and the isospin breaking ratios m_{u}/m_{d}=0.485(11)(8)(14), R=38.2(1.1)(0.8)(1.4), and Q=23.4(0.4)(0.3)(0.4). Our results exclude the m_{u}=0 solution to the strong CP problem by more than 24 standard deviations.

Calculation of the Hadronic Vacuum Polarization Disconnected Contribution to the Muon Anomalous Magnetic Moment.

We report the first lattice QCD calculation of the hadronic vacuum polarization (HVP) disconnected contribution to the muon anomalous magnetic moment at physical pion mass. The calculation uses a refined noise-reduction technique that enables the control of statistical uncertainties at the desired level with modest computational effort. Measurements were performed on the 48^{3}×96 physical-pion-mass lattice generated by the RBC and UKQCD Collaborations. We find the leading-order hadronic vacuum polarization a_{µ}^{HVP(LO)disc}=-9.6(3.3)(2.3)×10^{-10}, where the first error is statistical and the second systematic.

Lattice Computation of the Nucleon Scalar Quark Contents at the Physical Point.

We present a QCD calculation of the u, d, and s scalar quark contents of nucleons based on 47 lattice ensembles with N_{f}=2+1 dynamical sea quarks, 5 lattice spacings down to 0.054 fm, lattice sizes up to 6 fm, and pion masses down to 120 MeV. Using the Feynman-Hellmann theorem, we obtain f_{ud}^{N}=0.0405(40)(35) and f_{s}^{N}=0.113(45)(40), which translates into σ_{πN}=38(3)(3) MeV, σ_{sN}=105(41)(37) MeV, and y_{N}=0.20(8)(8) for the sigma terms and the related ratio, where the first errors are statistical and the second errors are systematic. Using isospin relations, we also compute the individual up and down quark contents of the proton and neutron (results in the main text).

Ab initio calculation of the neutron-proton mass difference.

The existence and stability of atoms rely on the fact that neutrons are more massive than protons. The measured mass difference is only 0.14% of the average of the two masses. A slightly smaller or larger value would have led to a dramatically different universe. Here, we show that this difference results from the competition between electromagnetic and mass isospin breaking effects. We performed lattice quantum-chromodynamics and quantum-electrodynamics computations with four nondegenerate Wilson fermion flavors and computed the neutron-proton mass-splitting with an accuracy of 300 kilo-electron volts, which is greater than 0 by 5 standard deviations. We also determine the splittings in the Σ, Ξ, D, and Ξcc isospin multiplets, exceeding in some cases the precision of experimental measurements.

Isospin splittings in the light-baryon octet from lattice QCD and QED.

While electromagnetic and up-down quark mass difference effects on octet baryon masses are very small, they have important consequences. The stability of the hydrogen atom against beta decay is a prominent example. Here, we include these effects by adding them to valence quarks in a lattice QCD calculation based on Nf=2+1 simulations with five lattice spacings down to 0.054 fm, lattice sizes up to 6 fm, and average up-down quark masses all the way down to their physical value. This allows us to gain control over all systematic errors, except for the one associated with neglecting electromagnetism in the sea. We compute the octet baryon isomultiplet mass splittings, as well as the individual contributions from electromagnetism and the up-down quark mass difference. Our results for the total splittings are in good agreement with experiment.

Kawasaki disease presenting as hepatitis.

Kawasaki disease (KD) presenting with an acute hepatitic picture is exceedingly rare. A 3.5-year-old girl presented with acute hepatitis and went on to satisfy the criteria for the diagnosis of KD for which she was treated. There were no cardiac abnormalities or sequelae.

Hospital laundry workers--an at-risk group for hepatitis A?

Twenty-two laundry personnel at St. Luke's Hospital, Malta, were tested for seropositivity to hepatitis A together with 37 nursing aides working in paediatric and infectious disease wards, matched for age, who were used as controls. IgG antibodies were found in 54.5% of laundry workers and 13.5% of nursing aides [odds ratio (OR) = 7.68; 95% confidence interval (CI) = 1.87-33.83]. Furthermore, laundry personnel consistently handling dirty linen prior to washing showed an OR of 16.50 (CI = 1.19-825.57) as compared with colleagues handling only clean items. These results would suggest that the increased exposure of hospital laundry workers to potentially infected linen can constitute a risk of occupational hepatitis A for this group of employees.

The distribution of codons by classes of triplets in the sequence of genes.

According to a criterion of symmetry-asymmetry, the triplets of the genetic code can be divided into four classes. In the genes of viruses and human mitochondria, the frequency by which a codon is followed by a codon of the same class is higher than that theoretically estimated. This is the consequence of the fact that in an initial stage of evolution many codons were duplicated.

Symmetrical-asymmetrical codons and hydrophobic-hydrophilic amino acids.

The symmetrical codons present in the first and third positions two purine (P) or two pyrimidine (p) bases (e.g. PNP or pNp), while the asymmetrical codons present in the first and third positions a purine and a pyrimidine base (e.g. PNp or pNP). The percentages of symmetrical and asymmetrical codons specifying hydrophobic and hydrophilic amino acids are similar in the genes of viruses and vertebrates, which utilise the "universal" genetic code, but they are different for the genes of human mitochondria and yeast mitochondria, which utilize two specific genetic codes.

The symmetries of the genetic code of mammalian mitochondria.

The genetic code of mammalian mitochondria presents some symmetric in the sequences of certain codons and in the relationships existing between the codons and aminoacids. These symmetries suggest the classification of codons in four classes and indicate that the evolution of the genetic code developed in four stages.