On the Search for Quasar Light Echoes

The UV radiation from a quasar leaves a characteristic pattern in the distribution of ionized hydrogen throughout the surrounding space. This pattern or light echo propagates through the intergalactic medium at the speed of light, and can be observed by its imprint on the Ly-alpha forest spectra of background sources. As the echo persists after the quasar has switched off, it offers the possibility of searching for dead quasars, and constraining their luminosities and lifetimes. We outline a technique to search for and characterize these light echoes. To test the method, we create artificial Ly-alpha forest spectra from cosmological simulations at z=3, apply light echoes and search for them. We show how the simulations can also be used to quantify the significance level of any detection. We find that light echoes from the brightest quasars could be found in observational data. With absorption line spectra of 100 redshift z~3-3.5 quasars or galaxies in a 1 square degree area, we expect that ~10 echoes from quasars with B band luminosities L_B=3x10^45 ergs/s exist that could be found at 95% confidence, assuming a quasar lifetime of ~10^7 yr. Even a null result from such a search would have interesting implications for our understanding of quasar luminosities and lifetimes.Comment: 9 pages, 7 figures, ApJ in pres

Environmental control study of space vehicles. Part III - Thermal control techniques and systems

General analysis for space vehicle thermal control systems and technique

Neurophysiological Effects of Harmonisation: The Effect of Harmonisation on Heart Rate Variability, Respiratory Rate and Electroencephalograph

 Harmonisation is a practice whereby the harmoniser, who is centered in silent prayer, opens and nourishes the subject's chakras, using touch. This technique has been widely used since 1933, with substantial anecdotal evidence about its benefits, but no published, peer-reviewed data. This preliminary study aimed to discover if standard physiological measuring techniques can detect any significant changes in the central and autonomic nervous systems and the cardiopulmonary system during harmonisation. A simple, comparative design was used, with one experimental group of 20 self-selecting, healthy women, naive to harmonisation. The results were compared with reference data, matched for age and gender, from non-intervention control studies conducted by the same experimenters in the same neurophysiological laboratory. An 3D-minute recording session determined baseline, intervention and stabilization measurements of electroencephalographic, electrocardiographic, and respiratory data. A significant lowering of brain activity was found during the opening phase of harmonisation, implying a state of increased mental focus coupled with a sense of calmness and relaxation, while significant changes to heart beatlrespiration ratios were observed during the nourishing phase. This suggests that different physiological processes affecting the central and autonomic nervous systems and the cardiopulmonary system may occur during different phases of harmonisation

Probing Dark Energy with Baryonic Acoustic Oscillations from Future Large Galaxy Redshift Surveys

We show that the measurement of the baryonic acoustic oscillations in large high redshift galaxy surveys offers a precision route to the measurement of dark energy. The cosmic microwave background provides the scale of the oscillations as a standard ruler that can be measured in the clustering of galaxies, thereby yielding the Hubble parameter and angular diameter distance as a function of redshift. This, in turn, enables one to probe dark energy. We use a Fisher matrix formalism to study the statistical errors for redshift surveys up to z=3 and report errors on cosmography while marginalizing over a large number of cosmological parameters including a time-dependent equation of state. With redshifts surveys combined with cosmic microwave background satellite data, we achieve errors of 0.037 on Omega_x, 0.10 on w(z=0.8), and 0.28 on dw(z)/dz for cosmological constant model. Models with less negative w(z) permit tighter constraints. We test and discuss the dependence of performance on redshift, survey conditions, and fiducial model. We find results that are competitive with the performance of future supernovae Ia surveys. We conclude that redshift surveys offer a promising independent route to the measurement of dark energy.Comment: submitted to ApJ, 24 pages, LaTe

Neurophysiological Effects of Harmonisation: The Effect of Harmonisation on Heart Rate Variability, Respiratory Rate and Electroencephalograph

 Harmonisation is a practice whereby the harmoniser, who is centered in silent prayer, opens and nourishes the subject's chakras, using touch. This technique has been widely used since 1933, with substantial anecdotal evidence about its benefits, but no published, peer-reviewed data. This preliminary study aimed to discover if standard physiological measuring techniques can detect any significant changes in the central and autonomic nervous systems and the cardiopulmonary system during harmonisation. A simple, comparative design was used, with one experimental group of 20 self-selecting, healthy women, naive to harmonisation. The results were compared with reference data, matched for age and gender, from non-intervention control studies conducted by the same experimenters in the same neurophysiological laboratory. An 3D-minute recording session determined baseline, intervention and stabilization measurements of electroencephalographic, electrocardiographic, and respiratory data. A significant lowering of brain activity was found during the opening phase of harmonisation, implying a state of increased mental focus coupled with a sense of calmness and relaxation, while significant changes to heart beatlrespiration ratios were observed during the nourishing phase. This suggests that different physiological processes affecting the central and autonomic nervous systems and the cardiopulmonary system may occur during different phases of harmonisation

The Correlation Function in Redshift Space: General Formula with Wide-angle Effects and Cosmological Distortions

A general formula for the correlation function in redshift space is derived in linear theory. The formula simultaneously includes wide-angle effects and cosmological distortions. The formula is applicable to any pair with arbitrary angle $\theta$ between lines of sight, and arbitrary redshifts, $z_1$, $z_2$, which are not necessarily small. The effects of the spatial curvature both on geometry and on fluctuation spectrum are properly taken into account, and thus our formula holds in a Friedman-Lema\^{\i}tre universe with arbitrary cosmological parameters $\Omega_0$ and $\lambda_0$. We illustrate the pattern of the resulting correlation function with several models, and also show that validity region of the conventional distant observer approximation is $\theta \le 10^\circ$.Comment: 45 pages including 9 figures, To Appear in Astrophys. J. 535 (2000

Radial Redshift Space Distortions

The radial component of the peculiar velocities of galaxies cause displacements in their positions in redshift space. We study the effect of the peculiar velocities on the linear redshift space two point correlation function. Our analysis takes into account the radial nature of the redshift space distortions and it highlights the limitations of the plane parallel approximation. We consider the problem of determining the value of \beta and the real space two point correlation function from the linear redshift space two point correlation function. The inversion method proposed here takes into account the radial nature of the redshift space distortions and can be applied to magnitude limited redshift surveys that have only partial sky coverage.Comment: 26 pages including 11 figures, to appear in Ap

Exploring Large-scale Structure with Billions of Galaxies

We consider cosmological applications of galaxy number density correlations to be inferred from future deep and wide multi-band optical surveys. We mostly focus on very large scales as a probe of possible features in the primordial power spectrum. We find the proposed survey of the Large Synoptic Survey Telescope may be competitive with future all-sky CMB experiments over a broad range of scales. On very large scales the inferred power spectrum is robust to photometric redshift errors, and, given a sufficient number density of galaxies, to angular variations in dust extinction and photometric calibration errors. We also consider other applications, such as constraining dark energy with the two CMB-calibrated standard rulers in the matter power spectrum, and controlling the effect of photometric redshift errors to facilitate the interpretation of cosmic shear data. We find that deep photometric surveys over wide area can provide constraints that are competitive with spectroscopic surveys in small volumes.Comment: 11 pages, 7 figures, ApJ accepted, references added, expanded discussion in Sec. 3.

The construction of identities in narratives about serious leisure occupations

Engagement in occupation contributes to the shaping of identity throughout the human life. The act of telling about such engagement involves interaction based on symbolic meaning; the speaker constructing an identity by conveying how the occupation is personally meaningful. This study explored meaning in narratives told by people who engage in serious leisure occupations. A total of 78 narratives were extracted from interviews with 17 people who invest considerable time and other resources into their leisure. Analysis focused on the content, structure and performance of each narrative in order to explore meaning. The meanings were organised into a framework based around three dimensions: the located self, the active self and the changing self. Each dimension has facets that the individual might emphasise, constructing a unique identity. The framework offers a structured basis for conceptualising how occupation contributes to the shaping of the internalised self and the socially situated identity

Ursinus College Alumni Journal, Fall 1948

Alumni register is in press • Students for tomorrow • Hail and farewell • International relations courses • President\u27s page • Seventy-eighth annual commencement activities • Alumni Day • Women\u27s Club takes inventory! • Have a look on the inside! • Alumni Executive Committee meeting • Locals • Addition and subtraction • Thus spake the registrar • 1948 summer session • Bunny Harshaw Vosters runner-up for tennis championship • News about town • Fetterolf House • Shifting scene • Activities of the Bears : Football; Soccer; Baseball; Track • Ursinus athlete wins Maxwell Award • Bears\u27 teams now have skilled trainerhttps://digitalcommons.ursinus.edu/alumnijournal/1033/thumbnail.jp