Stellar Forensics II: Millisecond Pulsar Binaries

We use the grid of models described in paper~I to analyse those millisecond pulsar binaries whose secondaries have been studied optically. In particular, we find cooling ages for these binary systems that range from $< 1 \rm Gyr$ to $\sim \rm 15 Gyr$. Comparison of cooling ages and characteristic spin down ages allows us to constrain the initial spin periods and spin-up histories for individual systems, showing that at least some millisecond pulsars had sub-Eddington accretion rates and long magnetic field decay times.Comment: Latex, 14 pages, and 15 postscript figures. Accepted by Monthly Notice

The Pulsar Kick Velocity Distribution

We analyse the sample of pulsar proper motions, taking detailed account of the selection effects of the original surveys. We treat censored data using survival statistics. From a comparison of our results with Monte Carlo simulations, we find that the mean birth speed of a pulsar is 250-300 km/s, rather than the 450 km/s foundby Lyne & Lorimer (1994). The resultant distribution is consistent with a maxwellian with dispersion $\sigma_v = 190 km/s$. Despite the large birth velocities, we find that the pulsars with long characteristic ages show the asymmetric drift, indicating that they are dynamically old. These pulsars may result from the low velocity tail of the younger population, although modified by their origin in binaries and by evolution in the galactic potential.Comment: Latex, 10 pages, and 11 postscript figures. Accepted by Monthly Notice

Proxying for Expected Returns with Price Earnings Ratios

Long-run regression models using the trailing earnings over price ratio to predict future returns suggested by Campbell and Shiller (1988, 2001) work quite well. However, in this note we show that this variable might result in a downward biased proxy for expected future returns. Instead we suggest using a moving average of the log of 1 plus the earnings price ratio when forecasting long-run returns. The empirical results for the S&P 500 show the superiority of our approach to existing ones.Earnings yield, Stock Return, Forecasting

Long-Run Regressions: Theory and Application to US Asset Markets

The question of long-run predictability in the aggregate US stock market is still unsettled. This is due to the lack of a robust method to judge the statistical significance of long-run regressions under the maintained hypothesis. By developing a spectral theory of long-run regressions with both long-run dependent and independent variables, we demonstrate a version of Engle's (1974) conjecture that asymptotically correct standard errors can be computed by multiplying the ordinary least squares standard errors by the square root of 2/3 times the length of the forecast horizon. We generalize Stambaugh's (1999) bias formula to the long-run regression model proposed in this paper. In addition, we find, that for persistent predictive variables, the OLS estimator in our regression model is more efficient than the estimator in the predictive regressions suggested by Campbell and Shiller (1988) and Hodrick (1992). Application of our method shows thatthe long-run earnings yield significantly predicts up to 69% of the variation in the 10-year S&P 500 real return, and up to 49% of long-run bond returns.Forecasting, stock returns, spectral analysis, Hansen-Hodrick standard errors

Towards the development of ethics guidelines for visual psychology: a review of relevant visual research ethics guidelines

Visual research methods are increasingly popular within psychology and the social sciences. However, psychology has yet to develop its own specific ethics guidelines for visual research methods. Currently, psychologists undertaking visual and arts-based research draw on ethics guidelines developed by and for allied disciplines that have a more established tradition of visual research, such as visual anthropology and visual sociology. While many of the principles of existing ethics guidelines from allied disciplines are applicable to psychological projects, psychological research has a distinct focus and potential applications, which would benefit from the generation of a set of bespoke guidelines. These should reflect our discipline’s long standing commitment to ethical research practice, and critical stance towards the limitations of inflexible formalistic principles. This article reviews existing guidelines for visual research and provides recommendations for visual research ethics guidelines for psychology, including the importance of ‘staged’ consent, anonymity vs. identification, and an expanded field of consideration which may include participants as image producers and owners; the individuals captured in the images taken by participants or researchers; and the impact of the research on the eventual audiences for these images

Scattering by randomly oriented ellipsoids: Application to aerosol and cloud problems

A program was developed for computing the scattering and absorption by arbitrarily oriented and randomly oriented prolate and oblate spheroids. This permits examination of the effect of particle shape for cases ranging from needles through spheres to platelets. Applications of this capability to aerosol and cloud problems are discussed. Initial results suggest that the effect of nonspherical particle shape on transfer of radiation through aerosol layers and cirrus clouds, as required for many climate studies, can be readily accounted for by defining an appropriate effective spherical particle radius

Grain boundary melting in ice

We describe an optical scattering study of grain boundary premelting in water ice. Ubiquitous long ranged attractive polarization forces act to suppress grain boundary melting whereas repulsive forces originating in screened Coulomb interactions and classical colligative effects enhance it. The liquid enhancing effects can be manipulated by adding dopant ions to the system. For all measured grain boundaries this leads to increasing premelted film thickness with increasing electrolyte concentration. Although we understand that the interfacial surface charge densities $q_s$ and solute concentrations can potentially dominate the film thickness, we can not directly measure them within a given grain boundary. Therefore, as a framework for interpreting the data we consider two appropriate $q_s$ dependent limits; one is dominated by the colligative effect and one is dominated by electrostatic interactions.Comment: 6 pages, 5 figure

Quantitative modeling of spin relaxation in quantum dots

We use numerically exact diagonalization to calculate the spin-orbit and phonon-induced triplet-singlet relaxation rate in a two-electron quantum dot exposed to a tilted magnetic field. Our scheme includes a three-dimensional description of the quantum dot, the Rashba and the linear and cubic Dresselhaus spin-orbit coupling, the ellipticity of the quantum dot, and the full angular description of the magnetic field. We are able to find reasonable agreement with the experimental results of Meunier et al. [Phys. Rev. Lett. 98, 126601 (2007)] in terms of the singlet-triplet energy splitting and the spin relaxation rate, respectively. We analyze in detail the effects of the spin-orbit factors, magnetic-field angles, and the dimensionality, and discuss the origins of the remaining deviations from the experimental data