16,694 research outputs found
A Deep Survey of HI-Selected Galaxies: The Sample and the Data
In a 21 cm neutral hydrogen survey of approximately 55 sq deg out to a
redshift of cz=8340 km/s, we have identified 75 extragalactic HI sources. These
objects comprise a well-defined sample of extragalactic sources chosen by means
that are independent of optical surface brightness selection effects. In this
paper we describe the Arecibo survey procedures and HI data, follow-up VLA HI
observations made of several unusual sources, and Kitt Peak B-, R-, and I-band
photometry for nearly all of the galaxies. We have also gathered information
for some of the optically detected galaxies within the same search volume. We
examine how samples generated by different types of search techniques overlap
with selection by HI flux. Only the least massive HI object, which is among the
lowest mass HI sources previously found, does not have a clear optical
counterpart, but a nearby bright star may hide low surface brightness emission.
However the newly-detected systems do have unusual optical properties. Most of
the 40 galaxies that were not previously identified in magnitude-limited
catalogs appear to be gas-dominated systems, and several of these systems have
HI mass-to-light ratios among the largest values ever previously found. These
gas-dominated objects also tend to have very blue colors, low surface
brightnesses, and no central bulges, which correlate strongly with their
relative star-to-gas content.Comment: 48 pages, 10 figures, Figure 3 included as 3 separate JPG images. To
appear in Ap J Supplement
Depression and Anxiety in Roman Catholic Secular Clergy
A nationally selected random sample of Roman Catholic secular priests was investigated using the Center for Epidemiological Studies-Depression scale and the State-Trait Anxiety Inventory Form Y. Additionally, a Self-Report Inventory requested information regarding participants\u27 demographics as well as four categories of predictor variables (i.e., Vocational Satisfaction, Social Support, Spiritual Activities, Physical Environment) potentially associated with depression and anxiety. The study yielded a return rate of 64%. Secular clergy reported significantly greater depression and anxiety (both state and trait) than are reported in the general population. Low Vocational Satisfaction was found to be predictive of depression as well as both state and trait anxiety. Additionally, low Social Support was found to be predictive of state and trait anxiety. When the significant predictor variables were conceptually collapsed, it appeared that both people and place were significantly related to Roman Catholic secular priests\u27 experience of depression and anxiety
INTEGRATED ASSESSMENT OF ENVIRONMENTAL EFFECTS FROM AGRICULTURAL PRODUCTION
Agriculture's impact on the environment is a complex research problem. A challenge to future economic research is to account for the interrelationship between agricultural production activities, soil productivity, erosion, and water quality. It will become increasingly important to determine not only the economic consequences, but also the environmental effectiveness of alternative policies aimed at improving resource use and quality. The application of biophysical simulation models to environmental quality problems provides a means to better understand the complex interaction between agricultural production and environmental quality.Environmental Economics and Policy,
Explicit finite-volume time-marching calculations of total temperature distributions in turbulent flow
A method was developed which calculates two-dimensional, transonic, viscous flow in ducts. The finite volume, time-marching formulation is used to obtain steady flow solutions of the Reynolds-averaged form of the Navier-Stokes equations. The entire calculation is performed in the physical domain. This paper investigates the introduction of a new formulation of the energy equation which gives improved transient behavior as the calculation converges. The effect of variable Prandtl number on the temperature distribution through the boundary layer is also investigated. A turbulent boundary layer in an adverse pressure gradient (M = 0.55) is used to demonstrate the improved transient temperature distribution obtained when the new formulation of the energy equation is used. A flat plate turbulent boundary layer with a supersonic free-stream Mach number of 2.8 is used to investigate the effect of Prandtl number on the distribution of properties through the boundary layer. The computed total temperature distribution and recovery factor agree well with the measurements when a variable Prandtl number is used through the boundary layer
An explicit finite-volume time-marching procedure for turbulent flow calculations
A method was developed which calculates two-dimensional, transonic, viscous flow in ducts. The finite-volume, time-marching formulation is used to obtain steady flow solutions of the Reynolds-averaged form of the Navier-Stokes equations. The entire calculation is performed in the physical domain. Control volumes are chosen so that smoothing of flow properties, typically required for stability, is not required. Different time steps are used in the different governing equations. A new pressure interpolation scheme is introduced which improves the shock capturing ability of the method. A multi-volume method for pressure changes in the boundary layer allows calculations which use very long and thin control volumes (length/height - 1000). The method is compared with two test cases. Essentially incompressible turbulent boundary layer flow in an adverse pressure gradient is calculated and the computed distributions of mean velocity and shear are in good agreement with the measurements. Transonic viscous flow in a converging diverging nozzle is calculated; the Mach number upstream of the shock is approximately 1.25. The agreement between the calculated and measured shock strength and total pressure losses is good
Thermodynamic evaluation of transonic compressor rotors using the finite volume approach
The development of a computational capability to handle viscous flow with an explicit time-marching method based on the finite volume approach is summarized. Emphasis is placed on the extensions to the computational procedure which allow the handling of shock induced separation and large regions of strong backflow. Appendices contain abstracts of papers and whole reports generated during the contract period
Depression and Contributors to Vocational Satisfaction in Roman Catholic Secular Clergy
A nationally selected, random sample of Roman Catholic secular (i.e., diocesan) priests was examined using the Center for Epidemiological Studies-Depression scale and an instrument developed for this study to assess contributors to priestsâ vocational satisfaction. In addition, a self-report inventory gathered information regarding participantsâ demographics as well as four categories of predictor variables (i.e., overall level of vocational satisfaction, social support, spiritual activities, physical environment). The study yielded a response rate of 45%. Secular clergy reported rates of depression approximately seven times greater than are found in the general population, and also indicated that the recent sexual abuse scandal in the Roman Catholic church had negatively affected their mood. Priestsâ engagement in sacramental activities contributed greatly to their vocational satisfaction, and low levels of vocational satisfaction were found to be most predictive of depression. Factors comprising priestsâ vocational satisfaction were External Manifestations (e.g., preaching, teaching), Internal Manifestations (e.g., prayer life, afïŹrmation of Godâs call), and Social Manifestations (e.g., relationships with parishioners, appreciation from others)
Spiral diffusion of rotating self-propellers with stochastic perturbation
Translationally diffusive behavior arising from the combination of
orientational diffusion and powered motion at microscopic scales is a known
phenomenon, but the peculiarities of the evolution of expected position
conditioned on initial position and orientation have been neglected. A theory
is given of the spiral motion of the mean trajectory depending upon propulsion
speed, angular velocity, orientational diffusion and rate of random chirality
reversal. We demonstrate the experimental accessibility of this effect using
both tadpole-like and Janus sphere dimer rotating motors. Sensitivity of the
mean trajectory to the kinematic parameters suggest that it may be a useful way
to determine those parameters
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