Does Inequality in Skills Explain Inequality of Earnings Across Advanced Countries?

The distribution of earnings and the distribution of skills vary widely among advanced countries, with the major English-speaking countries, the US, UK, and Canada, having much greater inequality in both earnings and skills than continental European Union countries. This raises the possibility that cross-country differences in the distribution of skills determine cross-country differences in earnings inequality. Using the International Adult Literacy Survey, we find that skill inequality explains only about 7% of the cross-country difference in inequality. Most striking, the dispersion of earnings in the US is larger in narrowly defined skill groups than is the dispersion of earnings for European workers overall. The bulk of cross-country differences in earnings inequality occur within skill groups, not between themWage inequality, distribution of skills, skills and education

Grand challenges in mass storage: A system integrator's perspective

The grand challenges are the following: to develop more innovation in approach; to expand the I/O barrier; to achieve increased volumetric efficiency and incremental cost improvements; to reinforce the 'weakest link' software; to implement improved architectures; and to minimize the impact of self-destructing technologies. Mass storage is defined as any type of storage system exceeding 100 GBytes in total size, under the control of a centralized file management scheme. The topics covered are presented in viewgraph form

Why Are Stocks So Risky?

With the decline in privately and publicly guaranteed benefits for pensions and health care, people increasingly must finance a greater share of their retirement expenses through their own savings. The relatively high long-term return on equity makes investments in stocks seem both an attractive and suitable means of accumulating the substantial wealth that savers will require. Yet, the 50 percent drop in the Standard & Poor’s 500 Index from May 2008 to March 2009 is only the latest reminder that stocks pose considerable risk for investors. In the past, equity returns over periods as long as 10 or 20 years have diverged substantially from their long-term averages, tarnishing the appeal of stocks even as investments for the long run...

Kelvin-Helmholtz Instability of Counter-Rotating Discs

Observations of galaxies and models of accreting systems point to the occurrence of counter-rotating discs where the inner part of the disc ($r<r_0$) is co-rotating and the outer part is counter-rotating. This work analyzes the linear stability of radially separated co- and counter-rotating thin discs. The strong instability found is the supersonic Kelvin-Helmholtz instability. The growth rates are of the order of or larger than the angular rotation rate at the interface. The instability is absent if there is no vertical dependence of the perturbation. That is, the instability is essentially three-dimensional. The nonlinear evolution of the instability is predicted to lead to a mixing of the two components, strong heating of the mixed gas, and vertical expansion of the gas, and annihilation of the angular momenta of the two components. As a result the heated gas will free-fall towards the disc's center over the surface of the inner disc

The Impact of Late-Career Health and Employment Shocks on Social Security and Other Wealth

About one-quarter of workers age 51 to 55 in 1992 developed health-related work limitations and about one-fifth were laid off from their jobs before age 62. Although late-career health and employment shocks often derail retirement savings plans, Social Security's disability insurance, spouse and survivor benefits, and progressive benefit formula provide important protections. In fact, health shocks increase Social Security's lifetime value, primarily because the system's disability insurance allows some disabled workers to collect benefits before age 62. However, if the system's disability insurance program did not exist, the onset of health-related work limitations would substantially reduce Social Security wealth

Clustering of Time Series Cytotoxicity Data

To study the effect of various toxicants on cells’ growth, the Alberta Centre for Toxicology did several in-vitro experiments, and concentration response curves (TCRCs) were generated. Each TCRC represents a time series that gives the temporal evolution of the number of cells, after exposure to a chemical with a certain concentration. Here we use the wavelet transform to extract important features from the original TCRC data, and we apply self organizing maps to classify the toxicants according to their adverse biological response. Presented in absentia on April 27, 2020 at Student Research Day held at MacEwan University in Edmonton, Alberta. (Conference cancelled.) Also presented on June 19-22, 2019 at the Classification Society meeting held at MacEwan University in Edmonton, Alberta. Faculty Mentor: Cristina Anton Department: Statistic

The Structure of 401(k) Fees

Increasingly, people are depending on 401(k) and similar defined contribution plans sponsored by their employers for their retirement income. As a result, participants in these plans also are paying more of their plans’ costs, ranging from administration and sales expenses to the cost of managing investments. These costs can take a substantial toll on retirement savings. Over a 30-year career, for example, paying an annual fee of 50 basis points can reduce the purchasing power of savings at the time of retirement by one-eighth. Employers who sponsor 401(k) plans have a fiduciary responsibility to ensure their plans’ fees are reasonable and communicated to participants. Recently, the Government Accountability Office reported that participants need more information and sponsors need to disclose this information more effectively to fulfill this responsibility. The Department of Labor is revising regulations to require sponsors to report the fees of their plans more clearly to their employees. Congress also has been holding hearings, inquiring if greater disclosure would help reduce costs within 401(k) plans...

A Pilot Survey for CIII] Emission in the Reionization Era: Gravitationally-Lensed z∼7−8\sim7-8 Galaxies in the Frontier Fields Cluster Abell 2744

We report results of a search for CIII] $\lambda \lambda$1907,1909 {\AA} emission using Keck's MOSFIRE spectrograph in a sample of 7 $z_{phot}\sim7-8$ candidates ($H\sim27$) lensed by the Hubble Frontier Field cluster Abell 2744. Earlier work has suggested the promise of using the CIII] doublet for redshift confirmation of galaxies in the reionization era given $Ly\alpha$ ($\lambda$1216 {\AA}) is likely attenuated by the neutral intergalactic medium. The primary challenge of this approach is the feasibility of locating CIII] emission without advanced knowledge of the spectroscopic redshift. With an integration time of 5 hours in the H-band, we reach a $5\sigma$ median flux limit (in between the skylines) of $1.5\times10^{-18}$ ergs cm$^{-2}$ sec$^{-1}$ but no convincing CIII] emission was found. We also incorporate preliminary measurements from two other CLASH/HFF clusters in which, similarly, no line was detected, but these were observed to lesser depth. Using the known distribution of OH emission and the photometric redshift likelihood distribution of each lensed candidate, we present statistical upper limits on the mean total CIII] rest-frame equivalent width for our $z\simeq7-8$ sample. For a signal/noise ratio of 5, we estimate the typical CIII] doublet rest-frame equivalent width is, with 95\% confidence, $<26\pm5$ {\AA}. Although consistent with the strength of earlier detections in brighter objects at $z\simeq6-7$, our study illustrates the necessity of studying more luminous or strongly-lensed examples prior to the launch of the James Webb Space Telescope.Comment: 7 pages, 4 figures, 1 table; accepted for publication in ApJ Letter