28 research outputs found
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 simulations with 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. 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.Comment: 5 pages, 3 figures. Version accepted for publication by Phys. Rev.
Let
Design and methods for a cluster randomized trial of the Sunless Study: A skin cancer prevention intervention promoting sunless tanning among beach visitors
<p>Abstract</p> <p>Background</p> <p>Skin cancer is the most prevalent yet most preventable cancer in the US. While protecting oneself from ultraviolet radiation (UVR) can largely reduce risk, rates of unprotected sun exposure remain high. Because the desire to be tan often outweighs health concerns among sunbathers, very few interventions have been successful at reducing sunbathing behavior. Sunless tanning (self-tanners and spray tans), a method of achieving the suntanned look without UVR exposure, might be an effective supplement to prevention interventions.</p> <p>Methods and Design</p> <p>This cluster randomized trial will examine whether a beach-based intervention that promotes sunless tanning as a substitute for sunbathing and includes sun damage imaging and sun safety recommendations is superior to a questionnaire only control group in reducing sunbathing frequency. Female beach visitors (N = 250) will be recruited from 2 public beaches in eastern Massachusetts. Beach site will be the unit of randomization. Follow-up assessment will occur at the end of the summer (1-month following intervention) and 1 year later. The primary outcome is average sunbathing time per week. The study was designed to provide 90% power for detecting a difference of .70 hours between conditions (standard deviation of 2.0) at 1-year with an intra-cluster correlation coefficient of 0.01 and assuming a 25% rate of loss to follow-up. Secondary outcomes include frequency of sunburns, use of sunless tanning products, and sun protection behavior.</p> <p>Discussion</p> <p>Interventions might be improved by promoting behavioral substitutes for sun exposure, such as sunless tanners, that create a tanned look without exposure to UVR.</p> <p>Trial registration</p> <p>NCT00403377</p
Cryptic subarctic diversity: a new bumblebee species from the Yukon and Alaska (Hymenoptera: Apidae)
Spectroscopic Identification of Cyclic Imide b(2)-Ions from Peptides Containing Gln and Asn Residues
Contains fulltext :
117239pos.pdf (postprint version ) (Open Access