A New Generalized Harmonic Evolution System

A new representation of the Einstein evolution equations is presented that is first order, linearly degenerate, and symmetric hyperbolic. This new system uses the generalized harmonic method to specify the coordinates, and exponentially suppresses all small short-wavelength constraint violations. Physical and constraint-preserving boundary conditions are derived for this system, and numerical tests that demonstrate the effectiveness of the constraint suppression properties and the constraint-preserving boundary conditions are presented.Comment: Updated to agree with published versio

Permutation Tests for Random Effects in Linear Mixed Models

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92041/1/j.1541-0420.2011.01675.x.pd

Solving Einstein's Equations With Dual Coordinate Frames

A method is introduced for solving Einstein's equations using two distinct coordinate systems. The coordinate basis vectors associated with one system are used to project out components of the metric and other fields, in analogy with the way fields are projected onto an orthonormal tetrad basis. These field components are then determined as functions of a second independent coordinate system. The transformation to the second coordinate system can be thought of as a mapping from the original ``inertial'' coordinate system to the computational domain. This dual-coordinate method is used to perform stable numerical evolutions of a black-hole spacetime using the generalized harmonic form of Einstein's equations in coordinates that rotate with respect to the inertial frame at infinity; such evolutions are found to be generically unstable using a single rotating coordinate frame. The dual-coordinate method is also used here to evolve binary black-hole spacetimes for several orbits. The great flexibility of this method allows comoving coordinates to be adjusted with a feedback control system that keeps the excision boundaries of the holes within their respective apparent horizons.Comment: Updated to agree with published versio

The economic impact of the 1964 Fair Employment Practices Act and subsequent executive orders on Black Americans

The economic status of the Black Americans has lagged far behind that of non-Black Americans in the last four centuries. The major reasons are manifested in (1) discrimination in employment practices by: employers, public and private employment agencies, labor organizations, and apprenticeship agencies; and (2) discrimination in distribution of factor inputs. To bring about economic equality the Presidents of the United States have issued various Executive Orders. Eight years ago the United States Congress enacted the Civil Rights Act of 1964 (Title VII of this Act is known as the Equal Employment Opportunity Title) and made it unlawful to discriminate in employment because of race, color, religion, sex, or national origin. The objective of this study is to examine the effects of the Civil Rights Act of 1964 and other Presidential Executive Orders on the related economic status of Black Americans. To examine this question, an economic model was developed. In this model, employers are assumed to have a "taste for discrimination," which causes them to have two different market demand curves for Blacks and non-Blacks. In hiring Black workers, employers feel that they incur a cost in addition to the market wage. Therefore Black workers are paid lower wages than non-Black workers in order for employers to compensate their "psychic cost." In this imperfect market Black workers are not perfect substitutes for non-Black workers. The enactment of the Fair Employment Practices laws (FEP) was, presumably, designed to encourage employers to regard Black workers as perfect substitutes for non-Black workers. Through causing employers "taste for discrimination" to disappear, it is expected that the demand curve for Black workers will shift to the right. The increase in demand would effect an increase in employment and wages for the Black Americans. On the other hand, negative effects could cause an increase in the wage rate and an increase in the unemployment rate. It is argued that the non-Black wage would remain the same, but, in the absence of eliminating the "taste for discrimination" the laws could result in an increase in the unemployment rate of the non-Blacks. The quantitative analysis was made by use of the census data in examining variables selected to measure economic status: viz., income, unemployment rates, and occupation distribution. In order to isolate the effects of the FEP laws on these variables, other variables were included, such as growth rate of Gross National Product and a dummy variable to test the impact of the war. Three statistical techniques were employed to evaluate the general overall economic progress of Blacks and the impact of the FEP laws. The statistical techniques are: least square regression analysis, analysis of variance, and information theory analysis technique. The regression results of many coefficients were not statistically significant at the five percent level of significance. In one instance the FEP laws effect variable was significant at the ten percent level of significance, suggesting that there may exist a relationship between that variable and unemployment rates. The statistical tests do not persuade one to conclude that the FEP laws have had significant impacts on the improvement of the economic status of the Black Americans. However, finding an expected sign on the estimated coefficients the FEP law effect variable suggests that the FEP laws, if more fully implemented, might lead to a reduction in unemployment and an increase in wage rate for Black Americans as a result of a shift in the demand curve for Black labor. The analysis of variance, revealed race itself to be dominantly significant as the cause of economic inequality of the two races. The racial entropy index distribution shows that the Blacks have made some progress in some occupations and have moved to better paying jobs. The descriptive analysis of the charges filed over the four year fiscal period, indicate that over 50 percent of the charges were directed to employers; and that the factor of race was very frequently given as the basis of the discrimination

Effect of progressive mandibular advancement on pharyngeal airway size in anesthetized adults.

BACKGROUND: General anesthesia in adult humans is associated with narrowing or complete closure of the pharyngeal airway. The purpose of this study was to determine the effect of progressive mandibular advancement on pharyngeal airway size in normal adults during intravenous infusion of propofol for anesthesia. METHODS: Magnetic resonance imaging was performed in nine normal adults during wakefulness and during propofol anesthesia. A commercially available intraoral appliance was used to manually advance the mandible. Images were obtained during wakefulness without the appliance and during anesthesia with the participants wearing the appliance under three conditions: without mandibular advancement, advancement to 50% maximum voluntary advancement, and maximum advancement. Using computer software, airway area and maximum anteroposterior and lateral airway diameters were measured on the axial images at the level of the soft palate, uvula, tip of the epiglottis, and base of the epiglottis. RESULTS: Airway area across all four airway levels decreased during anesthesia without mandibular advancement compared with airway area during wakefulness (P \u3c 0.007). Across all levels, airway area at 50% advancement during anesthesia was less than that at centric occlusion during wakefulness (P = 0.06), but airway area with maximum advancement during anesthesia was similar to that during wakefulness (P = 0.64). In general, anteroposterior and lateral airway diameters during anesthesia without mandibular advancement were decreased compared with wakefulness and were restored to their wakefulness values with 50% and/or maximal advancement. CONCLUSIONS: Maximum mandibular advancement during propofol anesthesia is required to restore the pharyngeal airway to its size during wakefulness in normal adults

A hypoenergetic diet with decreased protein intake does not reduce lean body mass in trained females

Purpose Increasing protein intake during energy restriction (ER) attenuates lean body mass (LBM) loss in trained males. However, whether this relationship exists in trained females is unknown. This study examined the impact of higher compared to lower protein intakes (35% versus 15% of energy intake) on body composition in trained females during 2 weeks of severe ER. Methods Eighteen well-trained females completed a 1-week energy balanced diet (HD100), followed by a 2-week hypoenergetic (40% ER) diet (HD60). During HD60, participants consumed either a high protein (HP; 35% protein, 15% fat) or lower protein (CON; 15% protein, 35% fat) diet. Body composition, peak power, leg strength, sprint time, and anaerobic endurance were assessed at baseline, pre-HD60, and post-HD60. Results Absolute protein intake was reduced during HD60 in the CON group (from 1.6 to 0.9 g·d·kgBM−1) and maintained in the HP group (~ 1.7 g·d·kgBM−1). CON and HP groups decreased body mass equally during HD60 (− 1.0 ± 1.1 kg; p = 0.026 and − 1.1 ± 0.7 kg; p = 0.002, respectively) and maintained LBM. There were no interactions between time point and dietary condition on exercise performance. Conclusion The preservation of LBM during HD60, irrespective of whether absolute protein intake is maintained or reduced, contrasts with findings in trained males. In trained females, the relationship between absolute protein intake and LBM change during ER warrants further investigation. Future recommendations for protein intake during ER should be expressed relative to body mass, not total energy intake, in trained females

End-of-life care of people with long-term neurological conditions

Guidance and protocols of end-of-life care have been directed towards the care of patients with cancer. It is possible to extrapolate some of these to people with long-term neurological conditions, but there are obvious differences. Neurological conditions have widely different time courses of progression, making the timing of these discussions challenging. The common issues around end-of-life care include knowing when to start discussions, approaching advance planning, managing common symptoms, diagnosing the dying phase, withdrawing life-sustaining treatments, providing support for family and carers and judging how to involve specialist palliative care teams. End-of-life care needs close collaboration between neurology, specialist palliative care and general practice