Comment on "Nucleon spin-averaged forward virtual Compton tensor at large Q^2"

In recent work, Hill and Paz apply the operator product expansion to forward doubly virtual Compton scattering. The resulting large-$Q^2$ form of the amplitude $W_1(0,Q^2)$ is compatible with the one we obtain by extrapolation of low-$Q^2$ results from a chiral effective field theory, providing support for our approach. That paper also presents a result for the two-photon contribution to the Lamb shift in muonic hydrogen that has a much larger uncertainty than in previous work. We show that this an overestimate arising from the inclusion of the proton pole term in the subtracted dispersion relation for $W_1$.Comment: 3 pages; version accepted for publicatio

A renormalisation-group treatment of two-body scattering

Nonrelativistic two-body scattering by a short-ranged potential is studied using the renormalisation group. Two fixed points are identified: a trivial one and one describing systems with a bound state at zero energy. The eigenvalues of the linearised renormalisation group are used to assign a systematic power-counting to terms in the potential near each of these fixed points. The expansion around the nontrivial fixed point is shown to be equivalent to the effective-range expansion.Comment: 6 pages (RevTeX), 1 figure (epsf); picture of RG flow and more discussion of momentum dependence adde

U(1) Axial Symmetry and Correlation Functions in the High Temperature Phase of QCD

Simple group-theoretical arguments are used to demonstrated that in the high temperature (chirally restored) phase of QCD with N massless flavours, all n-point correlation functions of quark bilinears are invariant under U(1) axial transformations provided n < N. In particular this implies that the two-point correlation function in the eta' channel is identical to that in the pion channel for N > 2. Unlike previous work, this result does not depend on the topological properties of QCD and can be formulated without explicit reference to functional integrals.Comment: 3 pages, RevTe

Jimmy Carter Bangor Visit_ Interview

Recording of interview with an unnamed individual regarding the visit to Bangor, Maine of U.S. President Jimmy Carter. The interview was conducted by University of Maine student Michael K. McGovern for a 1978 class project, as part of history course for Professor David Smith at the University of Maine. The tape of the recording is incorrectly labeled as being an interview with David Smith

Spin polarisabilities of the nucleon at NLO in the chiral expansion

We present a calculation of the fourth-order (NLO) contribution to spin-dependent Compton scattering in heavy-baryon chiral perturbation theory, and we give results for the four spin polarisabilities. No low-energy constants, except for the anomalous magnetic moments of the nucleon, enter at this order. For forward scattering the fourth-order piece of the spin polarisability of the proton turns out to be almost twice the size of the leading piece, with the opposite sign. This leads to the conclusion that no prediction can currently be made for this quantity. For backward scattering the fourth-order contribution is much smaller than the third-order piece which is dominated by the anomalous scattering, and so cannot explain the discrepancy between the CPT result and the current best experimental determination.Comment: 8 pages, 2 figures, revtex. Minor typos corrected and reference adde

Off-shell effects and consistency of many-body treatments of dense matter

Effective field theory requires all observables to be independent of the representation used for the quantum field operators. It means that off-shell properties of the interactions should not lead to any observable effects. We analyse this issue in the context of many-body approaches to nuclear matter, where it should be possible to shift the contributions of lowest order in purely off-shell two-body interactions into three-body forces. We show that none of the commonly used truncations of the two-body scattering amplitude such as the ladder, Brueckner-Hartree-Fock or parquet approximations respect this requirement.Comment: 5 pages, RevTeX, 6 figure

Ageism in Consent? In a decision-making capable geriatric orthopaedic trauma patient population, does increased age impact who physicians consent for surgical fixation?

Introduction: Persistent misconceptions of frailty and dementia in geriatric patients impact physician-patient communication and leave patients vulnerable to disempowerment. Our study examines the consenting process in an orthogeriatric trauma patient population to determine if there is a relationship between increased age at presentation and utilization of health care proxies (HCPs) for surgical procedure consent. Methods: We retrospectively reviewed medical records of patients aged 65 and older admitted for an operative fracture between 2013 and 2016. Patients were considered decision-making capable if there was absence of history of cognitive impairment prior to surgical consent and if the patients screened negative in a pre-surgical Confusion Assessment Method (CAM) and Mini-Cog Assessment. Data was analyzed via chi-squared and t-test analysis in SPSS. Results: 510 patients were included, and 276 (54.1%) patients were deemed capable of consent. 27 (9.8%) decision-making capable patients had HCPs consent for surgery. 20 of the 27 (74.1%) were 80 years of age or older and 7 patients between 70 and 79 had HCP consent. (p=0.07). HCP consent was significant for age (p\u3c0.001), income level (p=0.03), and HCP physically present at consult (p\u3c0.001). Additionally, language other than English was found to be a significant predictor of HCP consent (p=0.035). Conclusion: It is concerning that cognitively intact geriatric orthopaedic trauma patients are not always consented for their own surgical procedures. Factors including age, income, and language contribute to increased risk of HCP consent. Increased physician vigilance and adoption of institutional consenting guidelines can reinforce appropriate respect of geriatric patients’ consenting capacity

Jimmy Carter Bangor Visit_Constantine (Nick) Albuns Interview

Recording of interview with school teacher Constantine (Nick) Albuns regarding the visit to Bangor, Maine of U.S. President Jimmy Carter. The interview was conducted by University of Maine student Michael K. McGovern for a 1978 class project, as part of history course for Professor David Smith at the University of Maine