Black-white wage inequality in the 1990s: a decade of progress

Using Current Population Survey data, we find that the gap between wages by black and white males declined during the 1990s at a rate of 0.59 percentage point per year. The reduction in occupational crowding appears to be most important in explaining this trend. Recent wage convergence was most rapid among younger workers with less than 10 years experience; for this group the black-white wage gap declined by 1.40 percentage points per year. Among younger workers greater occupational diversity and a reduction in unexplained or residual differences are important in explaining this trend. For both younger and older workers, general wage inequality tempered the rate of wage convergence between blacks and whites during the 1990s.Income distribution ; Wages

Multidimensional Simulations of Rotating Pair Instability Supernovae

We study the effects of rotation on the dynamics, energetics and Ni-56 production of Pair Instability Supernova explosions by performing rotating two-dimensional ("2.5-D") hydrodynamics simulations. We calculate the evolution of eight low metallicity (Z = 10^-3, 10^-4 Zsun) massive (135-245 Msun) PISN progenitors with initial surface rotational velocities 50% that of the critical Keplerian value using the stellar evolution code MESA. We allow for both the inclusion and the omission of the effects of magnetic fields in the angular momentum transport and in chemical mixing, resulting in slowly-rotating and rapidly-rotating final carbon-oxygen cores, respectively. Increased rotation for carbon-oxygen cores of the same mass and chemical stratification leads to less energetic PISN explosions that produce smaller amounts of Ni-56 due to the effect of the angular momentum barrier that develops and slows the dynamical collapse. We find a non-monotonic dependence of Ni-56 production on rotational velocity in situations when smoother composition gradients form at the outer edge of the rotating cores. In these cases, the PISN energetics are determined by the competition of two factors: the extent of chemical mixing in the outer layers of the core due to the effects of rotation in the progenitor evolution and the development of angular momentum support against collapse. Our 2.5-D PISN simulations with rotation are the first presented in the literature. They reveal hydrodynamic instabilities in several regions of the exploding star and increased explosion asymmetries with higher core rotational velocity.Comment: 31 pages, 23 figures, accepted for publication in the Ap

Phase modulating with odd and even finite power series of a modulating signal

Method and apparatus is presented for producing a phase-modulated waveform having a high degree of linearity between the modulating signal and the phase of the modulated carrier signal. Two signals representing finite odd and even power series transformations of the modulating signal are produced and multiplied with two quadrature components of the input carrier signal, respectively. One of the multiplied signals is subtracted from the other and the resulting signal is hard-limited to produce a phase-modulated output signal. The means for producing the two signals representing the odd and even power series of the modulating signal includes means for varying the coefficients of the two power series. By means of an existing computer program, the coefficients of the two power series are selected such that there is an extremely high degree of linearity between the modulating signal and the phase of the modulated carrier signal

Wide deviation phase modulator

Modulator produces phase-modulated waveform having high modulating linearity. Technique is inherently wideband with respect to carrier frequency and can operate over decade carrier frequency range without adjustments. Circuit performance is both mathematically predictable and highly reproducible

Core-Collapse Supernova Simulations including Neutrino Interactions from the Virial EOS

Core-collapse supernova explosions are driven by a central engine that converts a small fraction of the gravitational binding energy released during core collapse to outgoing kinetic energy. The suspected mode for this energy conversion is the neutrino mechanism, where a fraction of the neutrinos emitted from the newly formed protoneutron star are absorbed by and heat the matter behind the supernova shock. Accurate neutrino-matter interaction terms are crucial for simulating these explosions. In this proceedings for IAUS 331, SN 1987A, 30 years later, we explore several corrections to the neutrino-nucleon scattering opacity and demonstrate the effect on the dynamics of the core-collapse supernova central engine via two dimensional neutrino-radiation-hydrodynamics simulations. Our results reveal that the explosion properties are sensitive to corrections to the neutral-current scattering cross section at the 10-20% level, but only for densities at or above $\sim 10^{12}$ g cm$^{-3}$Comment: 6 pages, 3 figures, appears in Proc. IAU Symposium 331, SN 1987A, 30 years later - Cosmic Rays and Nuclei from Supernovae and Their Aftermath

Effect of blockage ratio on drag and pressure distributions for bodies of revolution at transonic speeds

Experimental data were obtained in two wind tunnels for 13 models over a Mach number range from 0.70 to 1.02. Effects of increasing test-section blockage ratio in the transonic region near a Mach number of 1.0 included change in the shape of the drag curves, premature drag creep, delayed drag divergence, and a positive increment of pressures on the model afterbodies. Effects of wall interference were apparent in the data even for a change in blockage ratio from a very low 0.000343 to an even lower 0.000170. Therefore, models having values of blockage ratio of 0.0003 - an order of magnitude below the previously considered safe value of 0.0050 - had significant errors in the drag-coefficient values obtained at speeds near a Mach number of 1.0. Furthermore, the flow relief afforded by slots or perforations in test-section walls - designed according to previously accepted criteria for interference-free subsonic flow - does not appear to be sufficient to avoid significant interference of the walls with the model flow field for Mach numbers very close to 1.0

Visualizing the Social Links of Election Monitors with ArcGIS

Spatial analysis of the network of personnel in election monitoring and democratization missions allows users to visualize the impact and interactions these individuals and mission teams have had. This project focuses on the integration of the ArcGIS geographic information system and a private Access database to allow the user to input, edit, and visualize spatial and temporal data during the research of election monitoring networks. These data include the individuals, the missions, the positions held, and the dates of each activity. As these missions and individuals interact through space and time, network analysis will yield nodes of importance. This analysis will assist anthropologists in their study of the spread of democracy and in their study of the individuals supporting election assistance

Discovery of a Large-scale Wall in the Direction of Abell 22

We report on the discovery of a large-scale wall in the direction of Abell 22. Using photometric and spectroscopic data from the Las Campanas Observatory and Anglo-Australian Telescope Rich Cluster Survey, Abell 22 is found to exhibit a highly unusual and striking redshift distribution. We show that Abell 22 exhibits a foreground wall-like structure by examining the galaxy distributions in both redshift space and on the colour-magnitude plane. A search for other galaxies and clusters in the nearby region using the 2dF Galaxy Redshift Survey database suggests that the wall-like structure is a significant large-scale, non-virialized filament which runs between two other Abell clusters either side of Abell 22. The filament stretches over at least >40 Mpc in length and 10 Mpc in width at the redshift of Abell 22.Comment: 6 pages, 4 figures, accepted for publication in MNRAS letter

The Financial Health of Hospitals: Critical Access and Rural Hospitals in West Virginia

Critical Access Hospitals and rural hospitals are the safety net community health providers across the United States and especially is rural, sparsely populated states like West Virginia. While many larger hospitals across the country are merging of forming other combinations, there has been a significant increase in the number of small hospital closures or transformation of their services. This study looks specifically at hospitals of 100 beds or less in West Virginia to determine if there are looming threats for these hospitals that may not only affect their ability to operate but which might also have significant impact on the availability and accessibility of many of West Virginia’s rural residents to timely, quality emergency, acute, primary and preventative health care

A Measurement of Total Quality Management in Selected North Carolina Community Colleges

Many of the colleges in the North Carolina Community College System have embarked on a quality journey to continuously improve the educational programs and services that they provide to their communities. The primary focus of this study was to determine the level of Total Quality Management (TQM) principles implemented in selected North Carolina community colleges and to determine if there was a difference in the perception of its implementation between administrators and faculty. Additionally, this study examined the influence of the following variables on the implementation of TQM in selected North Carolina community colleges: personal factors (age, gender, ethnicity, and length of employment) and organizational factors (length of institutional involvement in TQM, institutional service area, institutional size, and institutional participation in the Carolina Quality Consortium). Furthermore, the study also gathered data about the positive and negative outcomes as a result of TQM/quality. Data for this study were obtained from a survey instrument that was based on the Malcolm Baldridge National Quality Award. The survey instrument was mailed to eight full-time administrators and eight full-time faculty members from 29 North Carolina community colleges. Twenty of the institutions belonged to the Carolina Quality Consortium. The remaining institutions represented a convenient sample of the 36 North Carolina community colleges that were not members of the Carolina Quality Consortium. Four hundred sixty-four surveys were mailed and 368 were returned. The overall percentage of survey return was 79.3. The Statistical Package for the Social Sciences (SPSS) was used for the analysis of data. An alpha level of.05 was used for all statistical tests. The major conclusions were: (1) there are different levels of TQM implementation among! the community colleges identified in this study, (2) there is a difference between the perception of TQM between administrators and faculty members, (3) the length of employment at the institution is a factor in the perception of the implementation of TQM, (4) age, gender, and ethnicity are not factors on the perceptions of the implementation of TQM, (5) the length of involvement in TQM, the service area, the size of the institution, and participation in the Carolina Quality Consortium are not factors on the overall quality ratings, (6) the positive outcomes perceived as having resulted from TQM/quality initiatives included improved communication, improved support systems, customer service, and increased involvement in planning and decision-making, and (7) the negative outcomes perceived as having resulted from TQM/quality were incongruence in philosophy and practice, too much time wasted, work overloads, and endless paperwork