Less than perfect quantum wavefunctions in momentum-space: How phi(p) senses disturbances in the force

We develop a systematic approach to determine the large |p| behavior of the momentum-space wavefunction, phi(p), of a one-dimensional quantum system for wich the position-space wavefunction, psi(x), has a discontinuous derivative at any order. We find that if the k-th derivative of the potential energy function has a discontinuity, there is a corresponding discontinuity in psi^{(k+2)}(x) at the same point. This discontinuity leads directly to a power-law tail in the momentum-space wavefunction proportional to 1/p^{k+3}. A number of familiar pedagogical examples are examined in this context, leading to a general derivation of the result.Comment: 22 pages, 2 figures. To appear in Am. J. Phy

The Challenge of Leadership in an Increasingly Diverse Society

Commencement address given by Louis W. Sullivan, President Emeritus, Morehouse School of Medicine and U. S. Secretary of Health and Human Services, to the Autumn 2002 graduating class of The Ohio State University, St. John Arena, Columbus, Ohio, December 13, 2002

Missing Persons: Minorities in the Health Professions, A Report of the Sullivan Commission on Diversity in the Healthcare Workforce

There is an imbalance in the makeup of the nation’s physicians, dentists, and nurses. This imbalance contributes to the gap in health status and the impaired access to health care experienced by a significant portion of our population. The Sullivan Commission on Diversity in the Healthcare Workforce finds that African Americans, Hispanics, American Indians, and certain segments of the nation’s Asian/Pacific Islander population are not present in significant numbers. Rather, they are missing! While some outstanding physicians, dentists, and nurses are minorities, access to a health professions career remains largely separate and unequal. This report, Missing Persons: Minorities in the Health Professions, examines the root causes of this challenge and provides detailed recommendations on how to increase the representation of minorities in the nation’s medical, dental, and nursing workforce.https://www.aacnnursing.org

Should we teach old dogs new tricks? the impact of community college retraining on older displaced workers

This paper estimates the returns to retraining for older displaced workers--those 35 or older--by estimating the impact that community college schooling has on their subsequent earnings. Our analysis relies on longitudinal administrative data covering workers who were displaced from jobs in Washington State during the first half of the 1990s and who subsequently remained attached to the state’s work force. Our database contains displaced workers' quarterly earnings records covering 14 years matched to the records of 25 of the state's community colleges. We find that older displaced workers participate in community college schooling at significantly lower rates than younger displaced workers. However, among those who participate in retraining, the per-period impact for older and younger displaced workers is similar. ; We estimate that one academic year of such schooling increases the long- term earnings by about 8 percent for older males and by about 10 percent for older females. These per-period impacts are in line with those reported in the schooling literature. These percentages do not necessarily imply that retraining older workers is a sound social investment. We find that the social internal rates of return from investments in older displaced workers' retraining are less than for younger displaced workers and likely less than those reported for schooling of children. However, our internal rate of return estimates are very sensitive to how we measure the opportunity cost of retraining. If we assume that these opportunity costs are zero, the internal rate of return from retraining older displaced workers is about 11 percent. By contrast, if we rely on our estimates of the opportunity cost of retraining, the internal rate of return may be less than 2 percent for older men and as low as 4 percent for older women.Displaced workers ; Education

Earnings Losses of Displaced Workers

The 1990-1991 recession has intensified concerns about the consequences of workers' job losses. To estimate the magnitude and temporal pattern of displaced workers' earnings losses, we exploit an unusual administrative data set that includes both employees' quarterly earnings histories and information about their firms. We find that when high-tenure workers separate from distressed firms their long-term losses average 25 percent per year. Further, their losses mount even prior to separation, are not limited to workers in a few industrial sectors, and are substantial even for those who find new jobs in similar firms. This evidence suggests that displaced workers' earnings losses result largely from the loss of some unidentified attribute of the employment relationship.earnings, wages, losses, displaced, dislocated, workers, Jacobson, LaLonde, Sullivan

Long-term earnings losses of high-seniority displaced workers

Displaced workers

Rings

https://digitalcommons.library.umaine.edu/mmb-vp/6113/thumbnail.jp

Porous Media Approach for Modeling Closed Cell Foam

In order to minimize boil off of the liquid oxygen and liquid hydrogen and to prevent the formation of ice on its exterior surface, the Space Shuttle External Tank (ET) is insulated using various low-density, closed-cell polymeric foams. Improved analysis methods for these foam materials are needed to predict the foam structural response and to help identify the foam fracture behavior in order to help minimize foam shedding occurrences. This presentation describes a continuum based approach to modeling the foam thermo-mechanical behavior that accounts for the cellular nature of the material and explicitly addresses the effect of the internal cell gas pressure. A porous media approach is implemented in a finite element frame work to model the mechanical behavior of the closed cell foam. The ABAQUS general purpose finite element program is used to simulate the continuum behavior of the foam. The soil mechanics element is implemented to account for the cell internal pressure and its effect on the stress and strain fields. The pressure variation inside the closed cells is calculated using the ideal gas laws. The soil mechanics element is compatible with an orthotropic materials model to capture the different behavior between the rise and in-plane directions of the foam. The porous media approach is applied to model the foam thermal strain and calculate the foam effective coefficient of thermal expansion. The calculated foam coefficients of thermal expansion were able to simulate the measured thermal strain during heat up from cryogenic temperature to room temperature in vacuum. The porous media approach was applied to an insulated substrate with one inch foam and compared to a simple elastic solution without pore pressure. The porous media approach is also applied to model the foam mechanical behavior during subscale laboratory experiments. In this test, a foam layer sprayed on a metal substrate is subjected to a temperature variation while the metal substrate is stretched to simulate the structural response of the tank during operation. The thermal expansion mismatch between the foam and the metal substrate and the thermal gradient in the foam layer causes high tensile stresses near the metal/foam interface that can lead to delamination