Cable arrangement for rigid tethering Patent

Force separation rigid tethering device using cable

Combined optical attitude and altitude indicating instrument Patent

Combined optical attitude and altitude indicating instrument for use in aircraft or spacecraf

Sound-Level Measurements of a Light Airplane Modified to Reduce Noise Reaching the Ground

An Army liaison-type airplane, representative of personal airplanes in the 150 to 200 horsepower class, has been modified to reduce propeller and engine noise according to known principles of airplane-noise reduction. Noise-level measurements demonstrate that, with reference to an observer on the ground, a noisy airplane of this class can be made quiet -- perhaps more quiet than necessary. In order to avoid extreme and unnecessary modifications, acceptable noise levels must be determined

Source Matching in the SDSS and RASS: Which Galaxies are Really X-ray Sources?

The current view of galaxy formation holds that all massive galaxies harbor a massive black hole at their center, but that these black holes are not always in an actively accreting phase. X-ray emission is often used to identify accreting sources, but for galaxies that are not harboring quasars (low-luminosity active galaxies), the X-ray flux may be weak, or obscured by dust. To aid in the understanding of weakly accreting black holes in the local universe, a large sample of galaxies with X-ray detections is needed. We cross-match the ROSAT All Sky Survey (RASS) with galaxies from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) to create such a sample. Because of the high SDSS source density and large RASS positional errors, the cross-matched catalog is highly contaminated by random associations. We investigate the overlap of these surveys and provide a statistical test of the validity of RASS-SDSS galaxy cross-matches. SDSS quasars provide a test of our cross-match validation scheme, as they have a very high fraction of true RASS matches. We find that the number of true matches between the SDSS main galaxy sample and the RASS is highly dependent on the optical spectral classification of the galaxy; essentially no star-forming galaxies are detected, while more than 0.6% of narrow-line Seyferts are detected in the RASS. Also, galaxies with ambiguous optical classification have a surprisingly high RASS detection fraction. This allows us to further constrain the SEDs of low-luminosity active galaxies. Our technique is quite general, and can be applied to any cross-matching between surveys with well-understood positional errors.Comment: 10 pages, 10 figures, submitted to The Astronomical Journal on 19 June 200

Spring School on Language, Music, and Cognition: Organizing Events in Time

The interdisciplinary spring school “Language, music, and cognition: Organizing events in time” was held from February 26 to March 2, 2018 at the Institute of Musicology of the University of Cologne. Language, speech, and music as events in time were explored from different perspectives including evolutionary biology, social cognition, developmental psychology, cognitive neuroscience of speech, language, and communication, as well as computational and biological approaches to language and music. There were 10 lectures, 4 workshops, and 1 student poster session. Overall, the spring school investigated language and music as neurocognitive systems and focused on a mechanistic approach exploring the neural substrates underlying musical, linguistic, social, and emotional processes and behaviors. In particular, researchers approached questions concerning cognitive processes, computational procedures, and neural mechanisms underlying the temporal organization of language and music, mainly from two perspectives: one was concerned with syntax or structural representations of language and music as neurocognitive systems (i.e., an intrapersonal perspective), while the other emphasized social interaction and emotions in their communicative function (i.e., an interpersonal perspective). The spring school not only acted as a platform for knowledge transfer and exchange but also generated a number of important research questions as challenges for future investigations

Topology of structure in the Sloan Digital Sky Survey: model testing

We measure the three-dimensional topology of large-scale structure in the Sloan Digital Sky Survey (SDSS). This allows the genus statistic to be measured with unprecedented statistical accuracy. The sample size is now sufficiently large to allow the topology to be an important tool for testing galaxy formation models. For comparison, we make mock SDSS samples using several state-of-the-art N-body simulations: the Millennium run of Springel et al. (2005)(10 billion particles), Kim & Park (2006) CDM models (1.1 billion particles), and Cen & Ostriker (2006) hydrodynamic code models (8.6 billion cell hydro mesh). Each of these simulations uses a different method for modeling galaxy formation. The SDSS data show a genus curve that is broadly characteristic of that produced by Gaussian random phase initial conditions. Thus the data strongly support the standard model of inflation where Gaussian random phase initial conditions are produced by random quantum fluctuations in the early universe. But on top of this general shape there are measurable differences produced by non-linear gravitational effects (cf. Matsubara 1994), and biasing connected with galaxy formation. The N-body simulations have been tuned to reproduce the power spectrum and multiplicity function but not topology, so topology is an acid test for these models. The data show a ``meatball'' shift (only partly due to the Sloan Great Wall of Galaxies; this shift also appears in a sub-sample not containing the Wall) which differs at the 2.5\sigma level from the results of the Millennium run and the Kim & Park dark halo models, even including the effects of cosmic variance.Comment: 13 Apj pages, 7 figures High-resolution stereo graphic available at http://www.astro.princeton.edu/~dclayh/stereo50.ep

The Galaxy Luminosity Function and Luminosity Density at Redshift z=0.1

Using a catalog of 147,986 galaxy redshifts and fluxes from the Sloan Digital Sky Survey (SDSS), we measure the galaxy luminosity density at z = 0.1 in five optical bandpasses corresponding to the SDSS bandpasses shifted to match their rest-frame shape at z = 0.1. We denote the bands (0.1)u, (0.1)g, (0.1)r, (0.1)i, (0.1)z with lambda(eff) = (3216; 4240; 5595; 6792; 8111 Angstrom), respectively. To estimate the luminosity function, we use a maximum likelihood method that allows for a general form for the shape of the luminosity function,fits for simple luminosity and number evolution, incorporates the flux uncertainties, and accounts for the flux limits of the survey. We find luminosity densities at z = 0.1 expressed in absolute AB magnitudes in a Mpc(3) to be (-14.10 +/- 0.15, -15.18 +/- 0.03, - 15.90 +/- 0.03, -16.24 +/- 0.03, -16.56 +/- 0.02) in ((0.1)u, (0.1)g, (0.1)r, (0.1)i, (0.1)z), respectively, for a cosmological model with Omega(0) = 0.3, Omega(Lambda) = 0.7, and h = 1 and using SDSS Petrosian magnitudes. Similar results are obtained using Sersic model magnitudes, suggesting that flux from outside the Petrosian apertures is not a major correction. In the (0.1)r band, the best-fit Schechter function to our results has phi* = (1.49 +/- 0.04) x 10(-2) h(3) Mpc(-3), M-* - 5 log(10) h = - 20.44 +/- 0.01, and alpha = - 1.05 +/- 0.01. In solar luminosities, the luminosity density in (0.1)r is (1.84 +/- 0.04) x 10(8) h L-0.1r,L-. Mpc(-3). Our results in the (0.1)g band are consistent with other estimates of the luminosity density, from the Two-Degree Field Galaxy Redshift Survey and the Millennium Galaxy Catalog. They represent a substantial change ( similar to 0.5 mag) from earlier SDSS luminosity density results based on commissioning data, almost entirely because of the inclusion of evolution in the luminosity function model