Model-dependence of the γZ\gamma Z dispersion correction to the parity-violating asymmetry in elastic epep scattering

We analyze the dispersion correction to elastic parity violating electron-proton scattering due to $\gamma Z$ exchange. In particular, we explore the theoretical uncertainties associated with modeling contributions of hadronic intermediate states. Taking into account constraints from low- and high-energy, parity-conserving electroproduction measurements, choosing different models for contributions from the non-resonant processes, and performing the corresponding flavor rotations to obtain the electroweak amplitude, we arrive at an estimate of the uncertainty in the total contribution to the parity-violating asymmetry. At the kinematics of the Q-Weak experiment, we obtain a correction to the asymmetry equivalent to a shift in the proton weak charge of $(0.0054\pm0.0020)$. This should be compared to the value of the proton's weak charge of \qwp=0.0713\pm0.0008 that includes SM contributions at tree level and one-loop radiative corrections. Therefore, we obtain a new Standard Model prediction for the parity-violating asymmetry in the kinematics of the Q-Weak experiment of $(0.0767\pm0.0008\pm0.0020_{\gamma Z})$. The latter error leads to a relative uncertainty of 2.8% in the determination of the proton's weak charge, and is dominated by the uncertainty in the isospin structure of the inclusive cross section. We argue that future parity-violating inelastic $ep$ asymmetry measurements at low-to-moderate $Q^2$ and $W^2$ could be exploited to reduce the uncertainty associated with the dispersion correction. Because the corresponding shift and error bar decrease monotonically with decreasing beam energy, a determination of the proton's weak charge with a lower-energy experiment or measurements of "isotope ratios" in atomic parity-violation could provide a useful cross check on any implications for physics beyond the Standard Model derived from the Q-Weak measurement.Comment: 25 pages, 17 figures, 4 tables; revised version accepted for publication in PR

Numerical Study of Cosmic Censorship in String Theory

Recently Hertog, Horowitz, and Maeda have argued that cosmic censorship can be generically violated in string theory in anti-de Sitter spacetime by considering a collapsing bubble of a scalar field whose mass saturates the Breitenlohner-Freedman bound. We study this system numerically and find that for various choices of initial data black holes form rather than naked singularities, implying that in these cases cosmic censorship is upheld.Comment: 16 pages, latex, 10 figures, uses JHEP.cls, v2: minor changes, version to be published in JHE

Skeletal muscle ferritin abundance is tightly related to plasma ferritin concentration in adults with obesity

Obesity is associated with complex perturbations to whole- body and tissue iron homeostasis. Recent evidence suggests a potentially important influence of iron storage in skeletal muscle on whole- body iron homeostasis, but this association is not clearly resolved. The primary aim of this study was to assess the relationship between whole- body and skeletal muscle iron stores by measuring the abundance of the key iron storage (ferritin) and import (transferrin receptor) proteins in skeletal muscle, as well as markers of whole- body iron homeostasis in men (n = 19) and women (n = 43) with obesity. Plasma ferritin concentration (a marker of whole- body iron stores) was highly correlated with muscle ferritin abundance (r = 0.77, P = 2 à  10- 13) and negatively associated with muscle transferrin receptor abundance (r = - 0.76, P = 1 à  10- 12). These relationships persisted when accounting for sex, age, BMI and plasma C- reactive protein concentration. In parallel with higher whole- body iron stores in our male versus female participants, men had 2.2- fold higher muscle ferritin abundance (P = 1 à  10- 4) compared with women. In accordance with lower muscle iron storage, women had 2.7- fold higher transferrin receptor abundance (P = 7 à  10- 10) compared with men. We conclude that muscle iron storage and import proteins are tightly and independently related to plasma ferritin concentration in adults with obesity, suggesting that skeletal muscle may be an underappreciated iron store.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163407/2/eph12853_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163407/1/eph12853.pd

Testing Effective String Models of Black Holes with Fixed Scalars

We solve the problem of mixing between the fixed scalar and metric fluctuations. First, we derive the decoupled fixed scalar equation for the four-dimensional black hole with two different charges. We proceed to the five-dimensional black hole with different electric (1-brane) and magnetic (5-brane) charges, and derive two decoupled equations satisfied by appropriate mixtures of the original fixed scalar fields. The resulting greybody factors are proportional to those that follow from coupling to dimension (2,2) operators on the effective string. In general, however, the string action also contains couplings to chiral operators of dimension (1,3) and (3,1), which cause disagreements with the semiclassical absorption cross-sections. Implications of this for the effective string models are discussed.Comment: 13 pages, harvmac; minor typos correcte

Benign perimesencephalic hemorrhage occurring after previous aneurysmal subarachnoid hemorrhage: a case report

<p>Abstract</p> <p>Introduction</p> <p>Both aneurysmal subarachnoid hemorrhage and benign perimesencephalic hemorrhage are well-described causes of spontaneous subarachnoid hemorrhage that arise as a result of different pathologic processes. To the best of the authors' knowledge, there have been no reports of both vascular pathologies occurring in the same individual.</p> <p>Case presentation</p> <p>A 51-year-old Caucasian woman with a history of aneurysmal subarachnoid hemorrhage presented five years after her initial treatment with ictal headache, meningismus, nausea and emesis similar to her previous bleeding event. Computed tomographic imaging revealed perimesencephalic bleeding remote from her previously coiled anterior communicating artery aneurysm. Both immediate and delayed diagnostic angiography revealed no residual filling of the previously coiled aneurysm and no other vascular anomalies, consistent with benign perimesencephalic hemorrhage. The patient had an uneventful hospital course and was discharged to home in good condition.</p> <p>Conclusions</p> <p>This report for the first time identifies benign perimesencephalic hemorrhage occurring in the setting of previous aneurysmal subarachnoid hemorrhage. The presence of a previously treated aneurysm can complicate the process of diagnosing benign perimesencephalic hemorrhage. Fortunately, in this case, the previously treated anterior communicating artery aneurysm was remote from the perimesencephalic hemorrhage and could be ruled out as a source. The patient's prior aneurysmal subarachnoid hemorrhage did not worsen the anticipated good outcome associated with benign perimesencephalic hemorrhage.</p

Nernst branes in gauged supergravity

We study static black brane solutions in the context of N = 2 U(1) gauged supergravity in four dimensions. Using the formalism of first-order flow equations, we construct novel extremal black brane solutions including examples of Nernst branes, i.e. extremal black brane solutions with vanishing entropy density. We also discuss a class of non-extremal generalizations which is captured by the first-order formalism.Comment: 44 pages, 3 figures, v2: added appendix B and references, minor typographic changes, v3: added some clarifying remarks, version published in JHE

Physics at a Fermilab Proton Driver

This report documents the physics case for building a 2 MW, 8 GeV superconducting linac proton driver at Fermilab.Comment: 52 pages, 15 figure

10 simple rules to create a serious game, illustrated with examples from structural biology

Serious scientific games are games whose purpose is not only fun. In the field of science, the serious goals include crucial activities for scientists: outreach, teaching and research. The number of serious games is increasing rapidly, in particular citizen science games, games that allow people to produce and/or analyze scientific data. Interestingly, it is possible to build a set of rules providing a guideline to create or improve serious games. We present arguments gathered from our own experience ( Phylo , DocMolecules , HiRE-RNA contest and Pangu) as well as examples from the growing literature on scientific serious games