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).

Canine rabies in Australia: a review of preparedness and research needs

Australia is unique as a populated continent in that canine rabies is exotic, with only one likely incursion in 1867. This is despite the presence of a widespread free-ranging dog population, which includes the naturalized dingo, feral domestic dogs and dingo-dog cross-breeds. To Australia's immediate north, rabies has recently spread within the Indonesian archipelago, with outbreaks occurring in historically free islands to the east including Bali, Flores, Ambon and the Tanimbar Islands. Australia depends on strict quarantine protocols to prevent importation of a rabid animal, but the risk of illegal animal movements by fishing and recreational vessels circumventing quarantine remains. Predicting where rabies will enter Australia is important, but understanding dog population dynamics and interactions, including contact rates in and around human populations, is essential for rabies preparedness. The interactions among and between Australia's large populations of wild, free-roaming and restrained domestic dogs require quantification for rabies incursions to be detected and controlled. The imminent risk of rabies breaching Australian borders makes the development of disease spread models that will assist in the deployment of cost-effective surveillance, improve preventive strategies and guide disease management protocols vitally important. Here, we critically review Australia's preparedness for rabies, discuss prevailing assumptions and models, identify knowledge deficits in free-roaming dog ecology relating to rabies maintenance and speculate on the likely consequences of endemic rabies for Australia.

Combination therapy with zidovudine prevents selection of human immunodeficiency virus type 1 variants expressing high-level resistance to L-697,661, a nonnucleoside reverse transcriptase inhibitor

L-697,661 is a human immunodeficiency virus type 1 (HIV-1)-specific nonnucleoside reverse transcriptase (RT) inhibitor. Its tolerability and activity in combination with zidovudine were evaluated in a 48-week double-blind study. One hundred nineteen zidovudine-naive HIV-1-infected patients with CD4 cell counts of 200-500/mm3 received either combination therapy, L-697,661 alone, or zidovudine alone. Activity was assessed by CD4 cell count changes. Selection for L-697,661-resistant virus was monitored by susceptibility testing of RT expressed by circulating viral RNA. Therapy was generally well tolerated. All groups receiving zidovudine exhibited transient increases in CD4 cell counts, while the L-697,661 monotherapy group showed a significant decline and yielded RT > 100-fold resistant to L-697,661 and associated with substitutions at RT residue 181. The RT from patients receiving combination therapy was maximally 15-fold less susceptible to L-697,661. Hence, cotreatment with zidovudine prevents selection of HIV-1 variants that are highly resistant to L-697,661 in patients naive to both compounds.