Recent Astrophysics Results from ORELA and Possible Future Experiments at ORELA and SNS

I present some recent results from experiments at the Oak Ridge Electron Linear Accelerator (ORELA) and discuss their impact in nuclear astrophysics. I then describe some possible future nuclear astrophysics experiments at ORELA and at the Spallation Neutron Source (SNS) being built in Oak Ridge. The SNS and ORELA are complementary, world-class facilities and both will be needed for important future experiments in nuclear astrophysics.Comment: 10 pages, 1 figure, 1 table. To be published in the proceedings of the Workshop on Astrophysics, Symmetries, and Applied Physics at Spallation Neutron Sources, Oak Ridge National Laboratory, March 200

Reduced neutron widths in the nuclear data ensemble: Experiment and theory do not agree

I have analyzed reduced neutron widths ({\Gamma}_{n}^0) for the subset of 1245 resonances in the nuclear data ensemble (NDE) for which they have been reported. Random matrix theory (RMT) predicts for the Gaussian orthogonal ensemble (GOE) that these widths should follow a \c{hi}^2 distribution having one degree of freedom ({\nu}=1) - the Porter Thomas distribution (PTD). Careful analysis of the {\Gamma}_{n}^2 values in the NDE rejects the validity of the PTD with a statistical significance of at least 99.97% ({\nu}=0.801\pm0.052). This striking disagreement with the RMT prediction is most likely due to the inclusion of significant p-wave contamination to the supposedly pure s-wave NDE. When an energy dependent threshold is used to remove the p-wave contamination, the PTD is still rejected with a statistical significance of at least 98.17% ({\nu}=1.217\pm0.092). Furthermore, examination of the primary references for the NDE reveals that many resonances in most of the individual data sets were selected using methods derived from RMT. Therefore, using the full NDE data set to test RMT predictions seems highly questionable. These results cast very serious doubt on claims that the NDE represents a striking confirmation of RMT.Comment: Accepted for publication in Phys. Rev.

A flight test method for pilot/aircraft analysis

In high precision flight maneuvres a pilot is a part of a closed loop pilot/aircraft system. The assessment of the flying qualities is highly dependent on the closed loop characteristics related to precision maneuvres like approach, landing, air-to-air tracking, air-to-ground tracking, close formation flying and air-to air refueling of the receiver. The object of a research program at DFVLR is the final flight phase of an air to ground mission. In this flight phase the pilot has to align the aircraft with the target, correct small deviations from the target direction and keep the target in his sights for a specific time period. To investigate the dynamic behavior of the pilot-aircraft system a special ground attack flight test technique with a prolonged tracking maneuvres was developed. By changing the targets during the attack the pilot is forced to react continously on aiming errors in his sights. Thus the closed loop pilot/aircraft system is excited over a wide frequency range of interest, the pilot gets more information about mission oriented aircraft dynamics and suitable flight test data for a pilot/aircraft analysis can be generated

True airspeed measured by airborne laser Doppler velocimeter

Velocimeter utilizing carbon dioxide laser measures true airspeed of aircraft. Results of flight tests indicate that clear-weather airspeeds can be measured with accuracy better than 0.1% at altitudes up to 3000 meters; measurements can be made at much greater altitudes in cloudy or turbid air

The Great Reconciliation

The Great Reconciliation is truly the core and center of the entire system of Christian doctrine. All other teachings of the Bible either lead up thereto, or they proceed therefrom. Thus the doctrine of the Law and of sin shows us the need of a reconciliation. The doctrine of grace and of the redemption through Christ shows us how this reconciliation was effected. The doctrine of the means of grace and of faith teaches us how this reconciliation is made known and offered to sinners and how the individual personally apprehends the same. The doctrine of the Church shows that all those who through faith have accepted this reconciliation constitute one large body in this world, the family of God\u27s children among men. The doctrine of sanctification shows us that all those who by faith are personally reconciled to God will gratefully consecrate their lives to His service. The doctrine of the last things, finally, tells us that all who have remained faithful unto the end will enter into the full communion with their heavenly Father

Value implications in inexpensive literature for young children

It was the purpose of this study to establish a list of wholesome personal and social values and to identify the types of values brought forth in inexpensive children\u27s literature

Analyzing epsilon'/epsilon in the 1/N_c Expansion

We present a recent analysis of epsilon'/epsilon in the 1/N_c expansion. We show that the 1/N_c corrections to the matrix element of Q_6 are large and positive, indicating a Delta I=1/2 enhancement similar to the one of Q_1 and Q_2 which dominate the CP conserving amplitude. This enhances the CP ratio and can bring the standard model prediction close to the measured value for central values of the parameters.Comment: One reference corrected. 5 pages, talk presented by P.H. Soldan at the 3. International Conference on B Physics and CP Violation, Taipei, Taiwan, December 3 - 7, 1999. Slightly expanded version of the article submitted to the proceeding

Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures

Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this reservoir may have fluctuated significantly over the course of Earth's history with particularly low levels in the Neoarchean - presumably as a result of biological activity. We used a biogeochemical box model to test which conditions are necessary to cause large swings in atmospheric N2 pressure. Parameters for our model are constrained by observations of modern Earth and reconstructions of biomass burial and oxidative weathering in deep time. A 1-D climate model was used to model potential effects on atmospheric climate. In a second set of tests, we perturbed our box model to investigate which parameters have the greatest impact on the evolution of atmospheric pN2 and consider possible implications for nitrogen cycling on other planets. Our results suggest that (a) a high rate of biomass burial would have been needed in the Archean to draw down atmospheric pN2 to less than half modern levels, (b) the resulting effect on temperature could probably have been compensated by increasing solar luminosity and a mild increase in pCO2, and (c) atmospheric oxygenation could have initiated a stepwise pN2 rebound through oxidative weathering. In general, life appears to be necessary for significant atmospheric pN2 swings on Earth-like planets. Our results further support the idea that an exoplanetary atmosphere rich in both N2 and O2 is a signature of an oxygen-producing biosphere.Comment: 33 pages, 11 figures, 2 tables (includes appendix), published in Astrobiolog