Individual differences in visual acuity and face matching ability

The visual acuity of the eyes varies outside the range of normal vision, requiring corrective lenses, but also within the normal range. This study investigated whether both types of variation relate to individual differences in face‐identity matching, considering this applied task requires perception of detail. Across two experiments, face‐matching accuracy correlated with variation in acuity when this fell outside the normal range of vision and was uncorrected with glasses or contact lenses. In contrast, variation in visual acuity within the normal range did not affect face‐matching accuracy, whereas matching accuracy at a given level of acuity could vary substantially. These results indicate that visual acuity is only a problem for occupations performing face‐identity matching when below‐normal acuity is not diagnosed or adequately corrected. In turn, these findings suggest that variation in acuity within the normal range is not a contributing factor to individual differences in face matching accuracy

5d-5f Electric-multipole Transitions in Uranium Dioxide Probed by Non-resonant Inelastic X-ray Scattering

Non-resonant inelastic x ray scattering (NIXS) experiments have been performed to probe the 5d-5f electronic transitions at the uranium O(4,5) absorption edges in uranium dioxide. For small values of the scattering vector q, the spectra are dominated by dipole-allowed transitions encapsulated within the giant resonance, whereas for higher values of q the multipolar transitions of rank 3 and 5 give rise to strong and well-defined multiplet structure in the pre-edge region. The origin of the observed non-dipole multiplet structures is explained on the basis of many-electron atomic spectral calculations. The results obtained demonstrate the high potential of NIXS as a bulk-sensitive technique for the characterization of the electronic properties of actinide materials.Comment: Submitted to Physical Review Letters on 31 December 200

Temperature-dependent Hall scattering factor and drift mobility in remotely doped Si:B/SiGe/Si heterostructures

Hall-and-Strip measurements on modulation-doped SiGe heterostructures and combined Hall and capacitance–voltage measurements on metal-oxide-semiconductor (MOS)-gated enhancement mode structures have been used to deduce Hall scattering factors, rH, in the Si1 – xGex two-dimensional hole gas. At 300 K, rH was found to be equal to 0.4 for x = 0.2 and x = 0.3. Knowing rH, it is possible to calculate the 300 K drift mobilities in the modulation-doped structures which are found to be 400 cm2 V – 1 s – 1 at a carrier density of 3.3 × 1011 cm – 2 for x = 0.2 and 300 cm2 V – 1 s – 1 at 6.3 × 1011 cm – 2 for x = 0.3, factors of between 1.5 and 2.0 greater than a Si pMOS control

Tagged particle in a sheared suspension: effective temperature determines density distribution in a slowly varying external potential beyond linear response

We consider a sheared colloidal suspension under the influence of an external potential that varies slowly in space in the plane perpendicular to the flow and acts on one selected (tagged) particle of the suspension. Using a Chapman-Enskog type expansion we derive a steady state equation for the tagged particle density distribution. We show that for potentials varying along one direction only, the tagged particle distribution is the same as the equilibrium distribution with the temperature equal to the effective temperature obtained from the violation of the Einstein relation between the self-diffusion and tagged particle mobility coefficients. We thus prove the usefulness of this effective temperature for the description of the tagged particle behavior beyond the realm of linear response. We illustrate our theoretical predictions with Brownian dynamics computer simulations.Comment: Accepted for publication in Europhys. Let

Understanding the complex phase diagram of uranium: the role of electron-phonon coupling

We report an experimental determination of the dispersion of the soft phonon mode along [1,0,0] in uranium as a function of pressure. The energies of these phonons increase rapidly, with conventional behavior found by 20 GPa, as predicted by recent theory. New calculations demonstrate the strong pressure (and momentum) dependence of the electron-phonon coupling, whereas the Fermi-surface nesting is surprisingly independent of pressure. This allows a full understanding of the complex phase diagram of uranium, and the interplay between the charge-density wave and superconductivity

Associations of the objective built environment along the route to school with children's modes of commuting: A multilevel modelling analysis (the SLIC study).

As active commuting levels continue to decline among primary schoolchildren, evidence about which built environmental characteristics influence walking or cycling to school remains inconclusive and is strongly context-dependent. This study aimed to identify the objective built environmental drivers of, and barriers to, active commuting to school for a multi-ethnic sample of 1,889 healthy primary schoolchildren (aged 5-11) in London, UK. Using cross-sectional multilevel ordered logistic regression modelling, supported by the spatial exploration of built environmental characteristics through cartography, the objective built environment was shown to be strongly implicated in children's commuting behaviour. In line with earlier research, proximity to school emerged as the prime variable associated with the choice for active commuting. However, other elements of the urban form were also significantly associated with children's use of active or passive modes of transport. High levels of accidents, crime and air pollution along the route to school were independently correlated with a lower likelihood of children walking or cycling to school. Higher average and minimum walkability and higher average densities of convenience stores along the way were independently linked to higher odds of active commuting. The significance of the relations for crime, air pollution and walkability disappeared in the fully-adjusted model including all built environmental variables. In contrast, relationships with proximity, traffic danger and the food environment were maintained in this comprehensive model. Black children, pupils with obesity, younger participants and those from high socioeconomic families were less likely to actively commute to school. There is thus a particular need to ensure that roads with high volumes of actively commuting children are kept safe and clean, and children's exposure to unhealthy food options along the way is limited. Moreover, as short commuting distances are strongly correlated with walking or cycling, providing high-quality education near residential areas might incite active transport to school