First Measurement Using Elliptically Polarized Photons of the Double-Polarization Observable E for γp→pπ^{0} and γp→nπ^{+}.

We report the measurement of the helicity asymmetry E for the pπ^{0} and nπ^{+} final states using, for the first time, an elliptically polarized photon beam in combination with a longitudinally polarized target at the Crystal Ball experiment at MAMI. The results agree very well with data that were taken with a circularly polarized photon beam, showing that it is possible to simultaneously measure polarization observables that require linearly (e.g.

Measurement of Compton Scattering at MAMI for the Extraction of the Electric and Magnetic Polarizabilities of the Proton.

A precise measurement of the differential cross sections dσ/dΩ and the linearly polarized photon beam asymmetry Σ_{3} for Compton scattering on the proton below pion threshold has been performed with a tagged photon beam and almost 4π detector at the Mainz Microtron. The incident photons were produced by the recently upgraded Glasgow-Mainz photon tagging facility and impinged on a cryogenic liquid hydrogen target, with the scattered photons detected in the Crystal Ball/TAPS setup. Using the highest statistics Compton scattering data ever measured on the proton along with two effective field theories (both covariant baryon and heavy-baryon) and one fixed-t dispersion relation model, constraining the fits with the Baldin sum rule, we have obtained the proton electric and magnetic polarizabilities with unprecedented precision: α_{E1}=10.

Single production off neutrons bound in deuteron with linearly polarized photons.

The quasifree photon beam asymmetry, , has been measured at photon energies, , from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time.

Helicity-Dependent Cross Sections for the Photoproduction of π^{0} Pairs from Nucleons.

The double-polarization observable E and helicity-dependent cross sections σ_{1/2}, σ_{3/2} have been measured for the photoproduction of π^{0} pairs off quasifree protons and neutrons at the Mainz MAMI accelerator with the Crystal Ball/TAPS setup. A circularly polarized photon beam was produced by bremsstrahlung from longitudinally polarized electrons and impinged on a longitudinally polarized deuterated butanol target. The reaction products were detected with an almost 4π covering calorimeter.

Signatures of the d^{*}(2380) Hexaquark in d(γ,pn[over →]).

We report a measurement of the spin polarization of the recoiling neutron in deuterium photodisintegration, utilizing a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300-700 MeV provides the first measurement of recoil neutron polarization at photon energies where the quark substructure of the deuteron plays a role, thereby providing important new constraints on photodisintegration mechanisms. A very high neutron polarization in a narrow structure centered around E_{γ}∼570  MeV is observed, which is inconsistent with current theoretical predictions employing nucleon resonance degrees of freedom.

Study of η and η' Photoproduction at MAMI.

The reactions γp→ηp and γp→η^{'}p are measured from their thresholds up to the center-of-mass energy W=1.96  GeV with the tagged-photon facilities at the Mainz Microtron, MAMI. Differential cross sections are obtained with unprecedented statistical accuracy, providing fine energy binning and full production-angle coverage.

Measurements of double-polarized compton scattering asymmetries and extraction of the proton spin polarizabilities.

The spin polarizabilities of the nucleon describe how the spin of the nucleon responds to an incident polarized photon. The most model-independent way to extract the nucleon spin polarizabilities is through polarized Compton scattering. Double-polarized Compton scattering asymmetries on the proton were measured in the Δ(1232) region using circularly polarized incident photons and a transversely polarized proton target at the Mainz Microtron.

Measurement of the transverse target and beam-target asymmetries in η meson photoproduction at MAMI.

We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the γ[over →]p[over →]→ηp reaction up to a center-of-mass energy of W=1.9  GeV. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI.

What do children with cancer know about their medications?

Objective: To explore the health literacy of children diagnosed with Acute Lymphoblastic Leukemia (ALL) through their knowledge of their medications.

Methods: Within the Basic Interpretive approach to qualitative research, semi-structured interviews were conducted with children from ages 6 to18 years (n=16) between May and September 2009 to determine their knowledge of medication properties, medication habits and medication teaching. REB approval was obtained.

The Development of Gaze Following in a Third-Party Context.

Infants follow the gaze of an individual with whom they are directly interacting by the end of the first year. By 18 months infants are capable of learning novel words in observational (or third-party) contexts (Floor & Akhtar, 2006). To examine third-party gaze following in 12- and 18-month-olds, the parent and experimenter engaged in a conversation while the infant was present.

Preoperative cardiovascular risk factor control in elective coronary artery bypass graft patients: a failure of present management.

Background: After coronary artery bypass graft (CABG) patients are at high risk for disease progression and future cardiac events. Risk factor control can reduce subsequent clinical events and mortality. The appropriateness of cardiovascular risk factor management in CABG patients is largely unknown.