Diffraction Analysis of 2-D Pupil Mapping for High-Contrast Imaging

Pupil-mapping is a technique whereby a uniformly-illuminated input pupil, such as from starlight, can be mapped into a non-uniformly illuminated exit pupil, such that the image formed from this pupil will have suppressed sidelobes, many orders of magnitude weaker than classical Airy ring intensities. Pupil mapping is therefore a candidate technique for coronagraphic imaging of extrasolar planets around nearby stars. Unlike most other high-contrast imaging techniques, pupil mapping is lossless and preserves the full angular resolution of the collecting telescope. So, it could possibly give the highest signal-to-noise ratio of any proposed single-telescope system for detecting extrasolar planets. Prior analyses based on pupil-to-pupil ray-tracing indicate that a planet fainter than 10^{-10} times its parent star, and as close as about 2 lambda/D, should be detectable. In this paper, we describe the results of careful diffraction analysis of pupil mapping systems. These results reveal a serious unresolved issue. Namely, high-contrast pupil mappings distribute light from very near the edge of the first pupil to a broad area of the second pupil and this dramatically amplifies diffraction-based edge effects resulting in a limiting attainable contrast of about 10^{-5}. We hope that by identifying this problem others will provide a solution.Comment: 23 pages, 13 figures, also posted to http://www.orfe.princeton.edu/~rvdb/tex/piaaFresnel/ms.pd

The Essential Aldo Leopold: Quotations and Commentaries

Review of: The Essential Aldo Leopold: Quotations and Commentaries. Leopold, Aldo

The Essential Aldo Leopold: Quotations and Commentaries

Review of: The Essential Aldo Leopold: Quotations and Commentaries. Leopold, Aldo

An evolutionarily conserved intronic region controls the spatiotemporal expression of the transcription factor Sox10

<p>Abstract</p> <p>Background</p> <p>A major challenge lies in understanding the complexities of gene regulation. Mutation of the transcription factor SOX10 is associated with several human diseases. The disease phenotypes reflect the function of SOX10 in diverse tissues including the neural crest, central nervous system and otic vesicle. As expected, the SOX10 expression pattern is complex and highly dynamic, but little is known of the underlying mechanisms regulating its spatiotemporal pattern. <it>SOX10 </it>expression is highly conserved between all vertebrates characterised.</p> <p>Results</p> <p>We have combined in vivo testing of DNA fragments in zebrafish and computational comparative genomics to identify the first regulatory regions of the zebrafish <it>sox10 </it>gene. Both approaches converged on the 3' end of the conserved 1^stintron as being critical for spatial patterning of <it>sox10 </it>in the embryo. Importantly, we have defined a minimal region crucial for this function. We show that this region contains numerous binding sites for transcription factors known to be essential in early neural crest induction, including Tcf/Lef, Sox and FoxD3. We show that the identity and relative position of these binding sites are conserved between zebrafish and mammals. A further region, partially required for oligodendrocyte expression, lies in the 5' region of the same intron and contains a putative CSL binding site, consistent with a role for Notch signalling in <it>sox10 </it>regulation. Furthermore, we show that β-catenin, Notch signalling and Sox9 can induce ectopic <it>sox10 </it>expression in early embryos, consistent with regulatory roles predicted from our transgenic and computational results.</p> <p>Conclusion</p> <p>We have thus identified two major sites of <it>sox10 </it>regulation in vertebrates and provided evidence supporting a role for at least three factors in driving <it>sox10 </it>expression in neural crest, otic epithelium and oligodendrocyte domains.</p

Determining Socio-Economic Impacts of New Gaming Venues in Four Lower Mainland Communities: Socio-Economic Issues and Impacts: First Impact Measures Report

Permission granted by the British Columbia Intellectual Property Program to reproduce this publication.The purpose of the study is to learn what, if any, economic and social costs and benefits emerge over time from the creation and operation of these four new venues. Its intent is to inform planning processes by the provincial government and other stakeholders. The study is being done in three waves: Baseline (2004) First Impact Measures (2005) Final Report with Second Impact Measures (2006) This document constitutes the first impact report. It compares present (2005) data with baseline social and economic data gathered prior to and during the opening of three of the four gaming venues (2004). The impact analysis in this report is limited because it is based on data collected shortly after the Casino opening dates. These delays were not anticipated at the start of the project, however the final report due in 2007 will have sufficient data to support impact analysis. The report is divided into two sections, Social Impacts and Economic Impacts.Ye

A Keck/HIRES Doppler Search for Planets Orbiting Metal-Poor Dwarfs. I. Testing Giant Planet Formation and Migration Scenarios

We describe a high-precision Doppler search for giant planets orbiting a well-defined sample of metal-poor dwarfs in the field. This experiment constitutes a fundamental test of theoretical predictions which will help discriminate between proposed giant planet formation and migration models. We present here details on the survey as well as an overall assessment of the quality of our measurements, making use of the results for the stars that show no significant velocity variation.Comment: 25 pages, 7 figures, accepted for publication in the Astrophysical Journa

Patterns of basal signaling heterogeneity can distinguish cellular populations with different drug sensitivities

Non small cell lung cancer H460 clones exhibit a high degree of heterogeneity in signaling states.Clones with similar patterns of basal signaling heterogeneity have similar paclitaxel sensitivities.Models of signaling heterogeneity among the clones can be used to classify sensitivity to paclitaxel for other cancer populations

Teologija na tržištu

One task intended to measure sensitivity to temporal fine structure (TFS) involves the discrimination of a harmonic complex tone from a tone in which all harmonics are shifted upwards by the same amount in hertz. Both tones are passed through a fixed bandpass filter centered on the high harmonics to reduce the availability of excitation-pattern cues and a background noise is used to mask combination tones. The role of frequency selectivity in this "TFS1" task was investigated by varying level. Experiment 1 showed that listeners performed more poorly at a high level than at a low level. Experiment 2 included intermediate levels and showed that performance deteriorated for levels above about 57 dB sound pressure level. Experiment 3 estimated the magnitude of excitation-pattern cues from the variation in forward masking of a pure tone as a function of frequency shift in the complex tones. There was negligible variation, except for the lowest level used. The results indicate that the changes in excitation level at threshold for the TFS1 task would be too small to be usable. The results are consistent with the TFS1 task being performed using TFS cues, and with frequency selectivity having an indirect effect on performance via its influence on TFS cues. (C) 2015 Acoustical Society of America

Line Broadening in Field Metal-poor Red Giant and Red Horizontal Branch Stars

We report 349 radial velocities for 45 metal-poor field red giant and red horizontal branch stars. We have have identified one new spectroscopic binary, HD 4306, and one possible such system, HD 184711. We also report 57 radial velocities for 11 of the 91 stars reported on previously by Carney et al. (2003). As was found in the previous study, radial velocity "jitter" is present in many of the most luminous stars. Excluding stars showing spectroscopic binary orbital motion, all 7 of the red giants with M(V) <= -2.0 display jitter, as well as 3 of the 14 stars with -2.0 <= M(V) <= -1.4. We have also measured line broadening in all of the new spectra, using synthetic spectra as templates. The most luminous red giants show significant line broadening, as do many of the red horizontal branch stars, and we discuss briefly possible causes.Comment: To appear in the Astronomical Journa