Racing away? Income inequality and the evolution of high incomes

This Briefing Note provides an analysis of the characteristics of high-income individuals and how their incomes have evolved over time. We begin by setting out recent trends in overall income inequality and why these lead us to focus on the pattern of income growth at the very top of the income distribution. We then present some basic facts about high-income individuals and how they compare with the rest of society (for example, what is their average before-tax income, what is their average tax rate, how much of total personal income do they receive, in what industries do they tend to work?). We then discuss recent trends in their incomes over time and how this pattern compares with that for the rest of the income distribution. We then briefly summarise some recent research on longer-term trends in high incomes. Appendix A will undertake a brief comparison with other sources of information - compensation of executives and measures of personal wealth

Intensity-Correlation Spectroscopy

A survey is given of techniques for spectroscopic analysis using intensity fluctuations. Particular attention is given to counting times, the role of macroscopic sources and detectors, and the electronic constraints placed on the observations

VIP: A knowledge-based design aid for the engineering of space systems

The Vehicles Implementation Project (VIP), a knowledge-based design aid for the engineering of space systems is described. VIP combines qualitative knowledge in the form of rules, quantitative knowledge in the form of equations, and other mathematical modeling tools. The system allows users rapidly to develop and experiment with models of spacecraft system designs. As information becomes available to the system, appropriate equations are solved symbolically and the results are displayed. Users may browse through the system, observing dependencies and the effects of altering specific parameters. The system can also suggest approaches to the derivation of specific parameter values. In addition to providing a tool for the development of specific designs, VIP aims at increasing the user's understanding of the design process. Users may rapidly examine the sensitivity of a given parameter to others in the system and perform tradeoffs or optimizations of specific parameters. A second major goal of VIP is to integrate the existing corporate knowledge base of models and rules into a central, symbolic form

630-mV open circuit voltage, 12% efficient n-Si liquid junction

We report the first experimental observation of a semiconductor/liquid junction whose open circuit voltage Voc is controlled by bulk diffusion/recombination processes. Variation in temperature, minority-carrier diffusion length, and/or in majority-carrier concentration produces changes in the Voc of the n-Si/CH3OH interface in accord with bulk recombination/diffusion theory. Under AM2 irradiation conditions, the extrapolated intercept at 0 K of Voc vs T plots yields activation energies for the dominant recombination process of 1.1–1.2 eV, in accord with the 1.12-eV band gap of Si. A crucial factor in achieving optimum performance of the n-Si/CH3OH interface is assigned to photoelectrochemical oxide formation, which passivates surface recombination sites at the n-Si/CH3OH interface and minimizes deleterious effects of pinning of the Fermi level at the Si/CH3OH junction. Controlled Si oxide growth, combined with optimization of bulk crystal parameters in accord with diffusion theory, is found to yield improved photoelectrode output parameters, with 12.0±1.5% AM2 efficiencies and AM1 Voc values of 632–640 mV for 0.2-Ω cm Si materials

Dynamical matrix of two-dimensional electron crystals

In a quantizing magnetic field, the two-dimensional electron (2DEG) gas has a rich phase diagram with broken translational symmetry phases such as Wigner, bubble, and stripe crystals. In this paper, we derive a method to get the dynamical matrix of these crystals from a calculation of the density response function performed in the Generalized Random Phase Approximation (GRPA). We discuss the validity of our method by comparing the dynamical matrix calculated from the GRPA with that obtained from standard elasticity theory with the elastic coefficients obtained from a calculation of the deformation energy of the crystal.Comment: Revised version published in Phys. Rev. B. 12 pages with 11 postscripts figure

Investigating the Martian atmosphere using the ExoMars 2016 lander

Accurate modelling of the Martian atmosphere is essential both for planning and completing future missions to the Martian surface, and for accurate analysis and interpretation of the data that they return. Large dust storms and local wind patterns can affect spacecraft landing profiles, and the level of dust present in the atmosphere may impact lander performance. The ExoMars 2016 Mission will carry an Entry, Descent and Landing Demonstrator Module (EDM), primarily designed to test the ability of ESA’s lander technology to carry a science package to the surface [1]. The Atmospheric Mars Entry and Landing Investigations and Analysis (AMELIA) team [2] will use the module’s entry and descent trajectory to characterise the structure of the atmosphere along the travelled landing profile, and to determine properties of the atmosphere, such as density and wind speed, over a wide altitude range from the upper atmosphere to the surface. Aerosol abundances, including atmospheric dust, will also be characterised. These combined datasets will enable more accurate predictions of the atmospheric environment that future landers will encounter. EDM’s surface science package, DREAMS (Dust characterisation, Risk assessment, and Environment Analyser on the Martian Surface), includes sensors to measure wind speed and direction, surface temperature, pressure, and the amount of atmospheric dust present near the surface [3]. We will use the descent and surface profile data collected by EDM to verify and improve current Martian atmospheric modelling completed at The Open University, using both the global circulation and mesoscale models. [1] Forget et al. (2011) Fourth International Workshop on the Mars Atmosphere: Modeling and Observations, Paris. [2] Ferri et al. (2012) 9th International Planetary Probe Workshop (IPPW9), Toulouse. [3] Esposito et al. (2013) EPSC Abstracts Vol. 8, EPSC2013-815

Ion-ion dynamic structure factor, acoustic modes and equation of state of two-temperature warm dense aluminum

The ion-ion dynamical structure factor and the equation of state of warm dense aluminum in a two-temperature quasi-equilibrium state, with the electron temperature higher than the ion temperature, are investigated using molecular-dynamics simulations based on ion-ion pair potentials constructed from a neutral pseudoatom model. Such pair potentials based on density functional theory are parameter-free and depend directly on the electron temperature and indirectly on the ion temperature, enabling efficient computation of two-temperature properties. Comparison with ab initio simulations and with other average-atom calculations for equilibrium aluminum shows good agreement, justifying a study of quasi-equilibrium situations. Analyzing the van Hove function, we find that ion-ion correlations vanish in a time significantly smaller than the electron-ion relaxation time so that dynamical properties have a physical meaning for the quasi-equilibrium state. A significant increase in the speed of sound is predicted from the modification of the dispersion relation of the ion acoustic mode as the electron temperature is increased. The two-temperature equation of state including the free energy, internal energy and pressure is also presented