Extraction of black hole coalescence waveforms from noisy data

We describe an independent analysis of LIGO data for black hole coalescence events. Gravitational wave strain waveforms are extracted directly from the data using a filtering method that exploits the observed or expected time-dependent frequency content. Statistical analysis of residual noise, after filtering out spectral peaks (and considering finite bandwidth), shows no evidence of non-Gaussian behaviour. There is also no evidence of anomalous causal correlation between noise signals at the Hanford and Livingston sites. The extracted waveforms are consistent with black hole coalescence template waveforms provided by LIGO. Simulated events, with known signals injected into real noise, are used to determine uncertainties due to residual noise and demonstrate that our results are unbiased. Conceptual and numerical differences between our RMS signal-to-noise ratios (SNRs) and the published matched-filter detection SNRs are discussed.Comment: 15 pages, 11 figures. Version accepted for publicatio

Two-dimensional GaAs/AlGaAs superlattice structures for solar cell applications: ultimate efficiency estimation

We calculate the band structure of a two-dimensional GaAs/AlGaAs superlattice and estimate the ultimate efficiency of solar cells using this type of structure for solar energy conversion. The superlattice under consideration consists of gallium arsenide rods forming a square lattice and embedded in aluminium gallium arsenide. The ultimate efficiency is determined versus structural parameters including the filling fraction, the superlattice constant, the rod geometry and the concentration of Al in the matrix material. The calculated efficiency of the superlattice proves to exceed the efficiency of each component material in the monolithic state in a wide range of parameter values.Comment: 11 pages, 7 figure

Chromatographic separation and identification of some peptides in partial hydroylsates of gelatin

Recently we have been engaged in a study of the chemical structure of collagen and gelatin with the object of determining the sequence of the amino acid residues in the polypeptide chains of these proteins. In the course of this study we have made considerable progress in the chromatographic analysis of complex mixtures of peptides and we have isolated and identified several simple peptides which occur in partial hydrolysates of gelatin. The initial separation of the mixture into zones of one or more peptides has been made on a column of ion exchange resin; further separation of the peptides in each zone has been achieved by chromatographing in the form of dinitrophenyl (DNP) peptides on columns of silicic acid-Celite. It is to be hoped that the particular combination of chromatographic methods which has been successfully used in the present study will be helpful in the resolution of the complex mixtures which result from the partial hydrolysis of other proteins

Literacy, Numeracy and Labour Market Outcomes in Canada

Most research on the contribution of human capital to economic growth and its role in the distribution of income uses indirect measures of human capital such as educational attainment and work experience. Such measures are arguably inputs into the production of human capital in the form of skills, competencies and knowledge. This study uses Canadian data from the international Adult Literacy Survey to analyse the role of directly observed skills -- specifically, prose, document and quantitative literacy -- on individual labour market earnings. The contributions of unobserved skills are taken into account using input measures (education and experience). We find that literacy skills have a large and statistically significant causal effect on earnings. As much as one-third of the return to education may be due to the combined effects of education on literacy and of literacy skills on earnings. In contrast, very little of the return to labour market experience is associated with the combined effects of experience on literacy and literacy skills on earnings.

Radio Images of 3C 58: Expansion and Motion of its Wisp

New 1.4 GHz VLA observations of the pulsar-powered supernova remnant 3C 58 have resulted in the highest-quality radio images of this object to date. The images show filamentary structure over the body of the nebula. The present observations were combined with earlier ones from 1984 and 1991 to investigate the variability of the radio emission on a variety of time-scales. No significant changes are seen over a 110 day interval. In particular, the upper limit on the apparent projected velocity of the wisp is 0.05c. The expansion rate of the radio nebula was determined between 1984 and 2004, and is 0.014+/-0.003%/year, corresponding to a velocity of 630+/-70 km/s along the major axis. If 3C 58 is the remnant of SN 1181, it must have been strongly decelerated, which is unlikely given the absence of emission from the supernova shell. Alternatively, the low expansion speed and a number of other arguments suggest that 3C 58 may be several thousand years old and not be the remnant of SN 1181.Comment: 12 pages; accepted for publication in the Astrophysical Journa

Bond disproportionation and dynamical charge fluctuations in the perovskite rare earth nickelates

We present a theory describing the local electronic properties of the perovskite rare earth nickelates--materials which have negative charge transfer energies, strong O $2p$ -- Ni $3d$ covalence, and breathing mode lattice distortions at the origin of highly studied metal-insulator and antiferromagnetic ordering transitions. Utilizing a full orbital, full correlation double cluster approach, we find strong charge fluctuations in agreement with a bond disproportionation interpretation. The unique double cluster formulation permits the inclusion of necessary orbital degeneracies and Coulomb interactions to calculate resonant x-ray spectral responses, with which we find excellent agreement with well-established experimental results. This previously absent, crucial link between theory and experiment provides validation of the recently proposed bond disproportionation theory, and provides an analysis methodology for spectroscopic studies of engineered phases of nickelates and other high valence transition metal compounds

Relativistic effects and angular dependence in the reaction antiproton-proton -> pi^- pi^+

We present a new fit to the LEAR data on antiproton-proton -> pi^- pi^+ differential cross sections and analyzing powers motivated by relativistic considerations. Within a quark model describing this annihilation we argue, since the pions are highly energetic, that relativistic effects cannot be neglected. The intrinsic pion wave functions are Lorentz transformed to the center of mass frame. This change in quark geometry gives rise to additional angular dependence in the transition operators and results in a relative enhancement of higher J \ge 2 partial wave amplitudes. The fit to the data is improved significantly.Comment: Revtex 4, 7 pages, 5 figures. Continuation and results of a previous paper: nucl-th/040305

Variational calculations for K-few-nucleon systems

Deeply bound KNN, KNNN and KNNNN states are discussed. The effective force exerted by the K meson on the nucleons is calculated with static nucleons. Next the binding energies are obtained by solving the Schrodinger equation or by variational calculations. The dominant attraction comes from the S-wave Lambda(1405) and an additional contribution is due to Sigma(1385). The latter state is formed at the nuclear peripheries and absorbs a sizable piece of the binding energy. It also generates new branches of quasi-bound states. The lowest binding energies based on a phenomenological KN input fall into the 40-80 MeV range for KNN, 90-150 MeV for KNNN and 120-220 MeV for K-alpha systems. The uncertainties are due to unknown KN interactions in the distant subthreshold energy region.Comment: 19 pages, 1 figur