Energy Dependence of Cu L2,3 Satellites using Synchrotron Excited X-ray Emission Spectroscopy

The L2,3 X-ray emission of Cu metal has been measured using monochromatic synchrotron radiation. The self-absorption effect in the spectra is shown to be very small in our experimental geometry. From the quantitative analysis of spectra recorded at different excitation energies, the L3/L2 emission intensity ratio and the partial Auger-width are extracted. High-energy satellite features on the L3 emission line are separated by a subtraction procedure. The satellite intensity is found to be slowly increasing for excitation energies between the L3, L2 and L1 core-level thresholds due to shake-up and shake-off transitions. As the excitation energy passes the L2 threshold, a step of rapidly increasing satellite intensity of the L3 emission is found due to additional Coster-Kronig processes.Comment: 8 pages, 3 figures, http://link.aps.org/doi/10.1103/PhysRevB.56.1223

Topographical Choroidal Thickness Change Following PDT for CSC: An OCT Case Report

Purpose. To describe topographical changes in choroidal thickness as measured by optical coherence tomography following photodynamic therapy (PDT) for central serous chorioretinopathy (CSC). Methods. Case report. Results. By 1 month following PDT, mean (SD) choroidal thickness decreased from 562 microns (24) to 424 microns (27) (P < 0.01) at 3 mm temporal to fovea, 483 microns (9) to 341 microns (21) (P < 0.01) at 1.5 mm temporal to fovea, 576 microns (52) to 370 microns (81) (P < 0.01) under the fovea, 442 microns (30) to 331 microns (54) (P < 0.04) at 1.5 mm nasal to fovea, and 274 microns (39) to 171 microns (17) (P < 0.01) at 3 mm nasal to fovea. The Location of greatest choroidal thickness (648 microns) prior to treatment was at point of leakage on fluorescein angiogram (FA). This region decreased to 504 microns following treatment. Conclusion. A decrease in choroidal thickness can be seen following PDT for CSC as far as 3 mm temporal and 3 mm nasal to fovea. The Location of greatest choroidal thickness may be at point of leakage on FA

Norden, reframed

This paper calls for Norden to be understood as a metaframe. Related formulations like “Nordic art” or “Nordic welfare” function as mesoframes. These trigger multiple framing devices. A cache of related framing devices constitutes a framing archive. Framing devices work best when operating unobtrusively such that inclusions, exclusions and inconsistencies are condoned or naturalised. Their artifice, however, becomes apparent whenever a frame is questioned. Questioning or criticising a frame gives rise to a framing dispute. The theoretical justification for these typologies is provided at the outset. This schema is then applied to a select range of empirical examples drawn largely from the disciplinary frames (Ernst 1996) of art history and museum studies. Despite this specificity it is envisaged that the general principles set out below can and will be used to address a variety of devices, disputes and archives in Norden and beyond

Electronic structure investigation of CeB6 by means of soft X-ray scattering

The electronic structure of the heavy fermion compound CeB6 is probed by resonant inelastic soft X-ray scattering using photon energies across the Ce 3d and 4d absorption edges. The hybridization between the localized 4f orbitals and the delocalized valence-band states is studied by identifying the different spectral contributions from inelastic Raman scattering and normal fluorescence. Pronounced energy-loss structures are observed below the elastic peak at both the 3d and 4d thresholds. The origin and character of the inelastic scattering structures are discussed in terms of charge-transfer excitations in connection to the dipole allowed transitions with 4f character. Calculations within the single impurity Anderson model with full multiplet effects are found to yield consistent spectral functions to the experimental data.Comment: 9 pages, 4 figures, 1 table, http://link.aps.org/doi/10.1103/PhysRevB.63.07510

Intramolecular vibronic dynamics in molecular solids: C60

Vibronic coupling in solid C60 has been investigated with a combination of resonant photoemission spectroscopy (RPES) and resonant inelastic x-ray scattering (RIXS). Excitation as a function of energy within the lowest unoccupied molecular orbital resonance yielded strong oscillations in intensity and dispersion in RPES, and a strong inelastic component in RIXS. Reconciling these two observations establishes that vibronic coupling in this core hole excitation leads to predominantly inelastic scattering and localization of the excited vibrations on the molecule on a femtosecond time scale. The coupling extends throughout the widths of the frontier valence bands.

Resonant inelastic soft-x-ray scattering spectra at the N1s and C1s edges of poly(pyridine-2,5-diyl)

Resonant inelastic scattering measurements of poly(pyridine-2,5-diyl) have been performed at the N1s and C1s edges using synchrotron radiation. For comparison, molecular orbital calculations of the spectra have been carried out with the repeat unit as a model molecule of the polymer chain. The resonant emission spectra show depletion of the p electron bands which is consistent with symmetry selection and momentum conservation rules. The depletion is most obvious in the resonant inelastic scattering spectra of carbon while the nitrogen spectra are dominated by lone pair n orbital emission of s symmetry and are less excitation energy dependent. By comparing the measurements to calculations an isomeric dependence of the resonant spectra is found giving preference to two of the four possible isomers in the polymer.Comment: 6 pages, 3 figures, http://www.sciencedirect.com/science/article/pii/S036820489800354

Social feedback enhances learning in Williams syndrome

Williams syndrome (WS) is a rare genetic condition characterized by high social interest and approach motivation as well as intellectual disability and anxiety. Despite the fact that social stimuli are believed to have an increased intrinsic reward value in WS, it is not known whether this translates to learning and decision making. Genes homozygously deleted in WS are linked to sociability in the general population, making it a potential model condition for understanding the social brain. Probabilistic reinforcement learning was studied with either social or non-social rewards for correct choices. Social feedback improved learning in individuals with Williams syndrome but not in typically developing controls or individuals with other intellectual disabilities. Computational modeling indicated that these effects on social feedback were mediated by a shift towards higher weight given to rewards relative to punishments and increased choice consistency. We conclude that reward learning in WS is characterized by high volatility and a tendency to learn how to avoid punishment rather than how to gain rewards. Social feedback can partly normalize this pattern and promote adaptive reward learning

Resonant soft X-ray Raman scattering of NiO

Resonant soft X-ray Raman scattering measurements on NiO have been made at photon energies across the Ni 2p absorption edges. The details of the spectral features are identified as Raman scattering due to d-d and charge-transfer excitations. The spectra are interpreted within the single impurity Anderson model, including multiplets, crystal-field and charge-transfer effects. At threshold excitation, the spectral features consists of triplet-triplet and triplet-singlet transitions of the 3d8 configuration. For excitation energies corresponding to the charge-transfer region in the Ni 2p X-ray absorption spectrum of NiO, the emission spectra are instead dominated by charge-transfer transitions to the 3d9L-1 final state. Comparisons of the final states with other spectroscopical techniques are also made.Comment: 9 pages, 2 figures, 2 tables, http://iopscience.iop.org/0953-8984/14/13/32