The Role of Final State Interactions in Quasielastic 56^{56}Fe(e,e′)(e,e') Reactions at large ∣q⃗∣|\vec q|

A relativistic finite nucleus calculation using a Dirac optical potential is used to investigate the importance of final state interactions [FSI] at large momentum transfers in inclusive quasielastic electronuclear reactions. The optical potential is derived from first-order multiple scattering theory and then is used to calculate the FSI in a nonspectral Green's function doorway approach. At intermediate momentum transfers excellent predictions of the quasielastic $^{56}$Fe$(e,e')$ experimental data for the longitudinal response function are obtained. In comparisons with recent measurements at $|{\vec q|}=1.14$~GeV/c the theoretical calculations of $R_L$ give good agreement for the quasielastic peak shape and amplitude, but place the position of the peak at an energy transfer of about $40$~MeV higher than the data.Comment: 13 pages typeset using revtex 3.0 with 6 postscript figures in accompanying uuencoded file; submitted to Phys. Rev.

Deconstructing the co-production ideal: Dilemmas of knowledge and representation in a co-design project with people with intellectual disabilities

Background: The co-production concept holds out the promise of forging new relationships between professionals and service users with intellectual disabilities. However, little empirical research explores the embodied practices of these projects occasion. We identify two key tensions intrinsic to such projects; the tension between expert/professional knowledge and lay/ experiential knowledge, and between co-producers as different from or typical of the public they are representing. Methods: We explored how these tensions were manifested and responded to in ongoing interactions by analysing video recordings of co-design groups where people with intellectual disabilities engaged in the production of Easy Read materials. Results: We noticed the instability of participants’ claims to expert/professional knowledge and the challenges of attending to and mobilising participants’ experiential knowledge within the constraints of the group task. Conclusions: Interactional dynamics were managed to preserve consensus and homogeneity within the groups, with the potential for reinforcing a limited identity associated with “intellectual disability.

A single-photon sampling architecture for solid-state imaging

Advances in solid-state technology have enabled the development of silicon photomultiplier sensor arrays capable of sensing individual photons. Combined with high-frequency time-to-digital converters (TDCs), this technology opens up the prospect of sensors capable of recording with high accuracy both the time and location of each detected photon. Such a capability could lead to significant improvements in imaging accuracy, especially for applications operating with low photon fluxes such as LiDAR and positron emission tomography. The demands placed on on-chip readout circuitry imposes stringent trade-offs between fill factor and spatio-temporal resolution, causing many contemporary designs to severely underutilize the technology's full potential. Concentrating on the low photon flux setting, this paper leverages results from group testing and proposes an architecture for a highly efficient readout of pixels using only a small number of TDCs, thereby also reducing both cost and power consumption. The design relies on a multiplexing technique based on binary interconnection matrices. We provide optimized instances of these matrices for various sensor parameters and give explicit upper and lower bounds on the number of TDCs required to uniquely decode a given maximum number of simultaneous photon arrivals. To illustrate the strength of the proposed architecture, we note a typical digitization result of a 120x120 photodiode sensor on a 30um x 30um pitch with a 40ps time resolution and an estimated fill factor of approximately 70%, using only 161 TDCs. The design guarantees registration and unique recovery of up to 4 simultaneous photon arrivals using a fast decoding algorithm. In a series of realistic simulations of scintillation events in clinical positron emission tomography the design was able to recover the spatio-temporal location of 98.6% of all photons that caused pixel firings.Comment: 24 pages, 3 figures, 5 table

Relativistic Coulomb Sum Rules for (e,e′)(e,e^\prime)

A Coulomb sum rule is derived for the response of nuclei to $(e,e^\prime)$ scattering with large three-momentum transfers. Unlike the nonrelativistic formulation, the relativistic Coulomb sum is restricted to spacelike four-momenta for the most direct connection with experiments; an immediate consequence is that excitations involving antinucleons, e.g., $N{\bar N}$ pair production, are approximately eliminated from the sum rule. Relativistic recoil and Fermi motion of target nucleons are correctly incorporated. The sum rule decomposes into one- and two-body parts, with correlation information in the second. The one-body part requires information on the nucleon momentum distribution function, which is incorporated by a moment expansion method. The sum rule given through the second moment (RCSR-II) is tested in the Fermi gas model, and is shown to be sufficiently accurate for applications to data.Comment: 32 pages (LaTeX), 4 postscript figures available from the author

Full-Folding Optical Potentials for Elastic Nucleon-Nucleus Scattering based on Realistic Densities

Optical model potentials for elastic nucleon nucleus scattering are calculated for a number of target nuclides from a full-folding integral of two different realistic target density matrices together with full off-shell nucleon-nucleon t-matrices derived from two different Bonn meson exchange models. Elastic proton and neutron scattering observables calculated from these full-folding optical potentials are compared to those obtained from `optimum factorized' approximations in the energy regime between 65 and 400 MeV projectile energy. The optimum factorized form is found to provide a good approximation to elastic scattering observables obtained from the full-folding optical potentials, although the potentials differ somewhat in the structure of their nonlocality.Comment: 21 pages, LaTeX, 17 postscript figure

ANKLE TAPING ALTERS SHANK-REARFOOT JOINT COUPLING DURING WALKING IN PATIENTS WITH CHRONIC ANKLE INSTABILITY AND HEALTHY CONTROLS

The purpose of this study was to analyze the shank-rearfoot joint coupling with and without ankle taping in patients with and without chronic ankle instability (CAI) during walking gait. Twenty-three patients (CAI,n=12, healthy,n=11) participated. Three-dimensional kinematics were collected using a 12 camera motion capture. Fifteen strides were collected while subjects walked. A vector coding analysis was performed to assess the magnitude, direction (?) and variability (VCV) in the coupling between the shank transverse plane and rearfoot frontal plane motion. Both groups had lower magnitude of coupled motion around initial contact while taped. VCV was significantly lower throughout the gait cycle in both groups while taped. Ankle taping appears to create a rigid coupling pattern in both healthy and CAI patients and may explain its role in prophylactically prevention of lateral ankle sprains

Differential susceptibility to insecticides by Leptinotarsa decemlineata [Coleoptera: Chrysomelidae] populations from western Canada

La sensibilité du doryphore de la pomme de terre (Leptinotarsa decemlineata) de trois provinces de l’Ouest canadien a été mesurée par bioessai sur papier filtre pour corroborer les comptes rendus faisant état de doryphores résistants aux insecticides au Manitoba, et pour comparer la situation au Manitoba à celles de la Saskatchewan et de l’Alberta. La sensibilité des doryphores a été mesurée pour cinq insecticides : les organophosphates azinphos-méthyl (Guthion) et méthamidophos (Monitor), le pyréthroïde perméthrine (Ambush), l’organochloré endosulfan (Endosulfan) et le carbamate carbaryl (Sevin). Les 12 populations du Manitoba examinées démontraient de la résistance à au moins un des insecticides. Toutes les populations ont été classées comme étant résistantes ou moyennement résistantes à la perméthrine; deux des populations ont été classées comme résistantes à l’azinphos-méthyl et trois au méthamidophos. Deux des quatre populations de la Saskatchewan ont été classées comme étant moyennement résistantes à l’azinphos-méthyl et au méthamidophos. Une résistance intermédiaire à la perméthrine a été trouvée dans 12 des 13 populations de l’Alberta, alors qu’une seule était très sensible. Deux populations se sont montrées moyennement résistantes à l’azinphos-méthyl et trois au méthamidophos. Dans les trois provinces, le taux de survie de diverses masses d’oeufs provenant de populations sensibles variait de 0 à 100 %, ce qui montre que des individus résistants, moyennement résistants et très sensibles coexistent dans ces populations. Avec l’expansion de la culture de la pomme de terre dans l’Ouest canadien et la détection d’une résistance aux insecticides dans les populations du doryphore de la pomme de terre, un programme de gestion de la résistance doit être mis en place pour éviter la sélection rapide de populations résistantes.The susceptibility of Colorado potato beetles (Leptinotarsa decemlineata) (CPB) from three provinces in western Canada was measured using a filter paper bioassay to substantiate the reported insecticide resistance by the beetle in Manitoba, and to compare the situation there to beetle populations from Saskatchewan and Alberta. Susceptibility of beetles was measured against five insecticides: the organophosphates, azinphos-methyl (Guthion), and methamidophos (Monitor); the pyrethroid, permethrin (Ambush); the organochlorine, endosulfan (Endosulfan); and the carbamate, carbaryl (Sevin). All 12 populations tested from Manitoba were found to have resistance to one or more of the insecticides. All populations were classified as either having resistance or intermediate resistance to permethrin; two of the populations were classified as having resistance to azinphos-methyl and three to methamidophos. Two of four populations from Saskatchewan were classified as having intermediate resistance to azinphos-methyl and methamidophos. Intermediate resistance to permethrin was recorded in 12 of the 13 populations from Alberta, with only one being highly susceptible. Two populations showed evidence of intermediate resistance to azinphos-methyl and three to methamidophos. In all three provinces, survival rate from different egg masses within the susceptible populations ranged from 0-100%, indicating the presence of individuals with either resistance, intermediate or high susceptibility within these populations. With the expanding potato acreage in western Canada and the detection of the CPB populations with resistance to insecticides, a resistance management program must be implemented to prevent the rapid selection of resistant populations

Total Cross Sections for Neutron Scattering

Measurements of neutron total cross-sections are both extensive and extremely accurate. Although they place a strong constraint on theoretically constructed models, there are relatively few comparisons of predictions with experiment. The total cross-sections for neutron scattering from $^{16}$O and $^{40}$Ca are calculated as a function of energy from $50-700$~MeV laboratory energy with a microscopic first order optical potential derived within the framework of the Watson expansion. Although these results are already in qualitative agreement with the data, the inclusion of medium corrections to the propagator is essential to correctly predict the energy dependence given by the experiment.Comment: 10 pages (Revtex 3.0), 6 fig