Early Air Force Flight Test Center (AFFTC) experience with Peripheral Vision Horizon Displays (PVHD)

Three separate Air Force Flight Test Center (AFFTC) tests were conducted in 1980 and 1981 on two models of the peripheral vision horizon displays (PVHD) (Malcolm Horizon). A fixed base simulator test was conducted with twenty test pilot subjects using the Flight Simulator Demonstration Model which incorporated a Helium Neon laser as the light bar medium. Two separate flight tests were conducted by the Test Pilot School classes 80A and 80B in a Twin Otter commuter aircraft using the Stage A Model PVHD. The Xenon lighted A Model was tested in its original configuration by class 80A. Class 80B used a modified configuration which incorporated an AFFTC designed and manufactured hood. With the hood, the PVHD projected a thinner, distinct light bar. Only a few general remarks concerning the tests and unrestricted, overall conclusions reached by the author are presented. The conclusions of all three AFFTC evaluations of the PVHD concept were that it has not yet been adequately evaluated. There seems to be a significant learning curve associated with the PVHD and the project pilots for Test Pilot School Class 80B only got a good start on the learning curve. A lengthy learning curve for the PVHD should be anticipated in view of the training period required for the attitude display indicator (ADI). This does seem to point out that the PVHD, in its present form, is simply not as compelling as the natural horizon. It can also be concluded that any attempt at a valid evaluation of the PVHD concept can be done only under instrument meteorological conditions (IMC) or validly simulated IMC conditions. The knee in the learning curve, however, may be reached without full IMC, although it may take much longer to reach

The assessment of pain in older people

Pain is under-recognised and under-treated in older people. It is a subjective, personal experience, only known to the person who suffers. The assessment of pain is particularly challenging in the presence of severe cognitive impairment, communication difficulties or language and cultural barriers. These guidelines set out the key components of assessing pain in older people, together with a variety of practical scales that may be used with different groups, including those with varying levels of cognitive or communication impairment. The purpose is to provide professionals with a set of practical skills to assess pain as the first step towards its effective management. The guidance has implications for all healthcare and social care staff and can be applied in all settings, including the older person’s own home, in care homes, and in hospital

Transport anomalies in a simplified model for a heavy electron quantum critical point

We discuss the transport anomalies associated with the development of heavy electrons out of a neutral spin fluid using the large-N treatment of the Kondo-Heisenberg lattice model. At the phase transition in this model the spin excitations suddenly acquire charge. The Higgs process by which this takes place causes the constraint gauge field to loosely ``lock'' together with the external, electromagnetic gauge field. From this perspective, the heavy fermion phase is a Meissner phase in which the field representing the difference between the electromagnetic and constraint gauge field, is excluded from the material. We show that at the transition into the heavy fermion phase, both the linear and the Hall conductivity jump together. However, the Drude weight of the heavy electron fluid does not jump at the quantum critical point, but instead grows linearly with the distance from the quantum critical point, forming a kind of ``gossamer'' Fermi-liquid.Comment: 15 pages, 3 figures. Small change in references in v

Discontinuous Molecular Dynamics for Rigid Bodies: Applications

Event-driven molecular dynamics simulations are carried out on two rigid body systems which differ in the symmetry of their molecular mass distributions. First, simulations of methane in which the molecules interact via discontinuous potentials are compared with simulations in which the molecules interact through standard continuous Lennard-Jones potentials. It is shown that under similar conditions of temperature and pressure, the rigid discontinuous molecular dynamics method reproduces the essential dynamical and structural features found in continuous-potential simulations at both gas and liquid densities. Moreover, the discontinuous molecular dynamics approach is demonstrated to be between 2 to 100 times more efficient than the standard molecular dynamics method depending on the specific conditions of the simulation. The rigid discontinuous molecular dynamics method is also applied to a discontinuous-potential model of a liquid composed of rigid benzene molecules, and equilibrium and dynamical properties are shown to be in qualitative agreement with more detailed continuous-potential models of benzene. Qualitative differences in the dynamics of the two models are related to the relatively crude treatment of variations in the repulsive interactions as one benzene molecule rotates by another.Comment: 14 pages, double column revte

Interaction Correction of Conductivity Near a Ferromagnetic Quantum Critical Point

We calculate the temperature dependence of conductivity due to interaction correction for a disordered itinerant electron system close to a ferromagnetic quantum critical point which occurs due to a spin density wave instability. In the quantum critical regime, the crossover between diffusive and ballistic transport occurs at a temperature $T^{\ast}=1/[\tau \gamma (E_{F}\tau)^{2}]$, where $\gamma$ is the parameter associated with the Landau damping of the spin fluctuations, $\tau$ is the impurity scattering time, and $E_{F}$ is the Fermi energy. For a generic choice of parameters, $T^{\ast}$ is few orders of magnitude smaller than the usual crossover scale $1/\tau$. In the ballistic quantum critical regime, the conductivity has a $T^{(d-1)/3}$ temperature dependence, where $d$ is the dimensionality of the system. In the diffusive quantum critical regime we get $T^{1/4}$ dependence in three dimensions, and $\ln^2 T$ dependence in two dimensions. Away from the quantum critical regime we recover the standard results for a good metal.Comment: 15 pages, 8 figure

Quantum Cluster Variables via Serre Polynomials

For skew-symmetric acyclic quantum cluster algebras, we express the quantum $F$-polynomials and the quantum cluster monomials in terms of Serre polynomials of quiver Grassmannians of rigid modules. As byproducts, we obtain the existence of counting polynomials for these varieties and the positivity conjecture with respect to acyclic seeds. These results complete previous work by Caldero and Reineke and confirm a recent conjecture by Rupel.Comment: minor corrections, reference added, example 4.3 added, 38 page

The Oxidation State of Iron in Silicate Minerals from the Matrices of CO Carbonaceous Chondrites

No abstract available