An analysis of pilot error-related aircraft accidents

A multidisciplinary team approach to pilot error-related U.S. air carrier jet aircraft accident investigation records successfully reclaimed hidden human error information not shown in statistical studies. New analytic techniques were developed and applied to the data to discover and identify multiple elements of commonality and shared characteristics within this group of accidents. Three techniques of analysis were used: Critical element analysis, which demonstrated the importance of a subjective qualitative approach to raw accident data and surfaced information heretofore unavailable. Cluster analysis, which was an exploratory research tool that will lead to increased understanding and improved organization of facts, the discovery of new meaning in large data sets, and the generation of explanatory hypotheses. Pattern recognition, by which accidents can be categorized by pattern conformity after critical element identification by cluster analysis

Breakdown of Angular Momentum Selection Rules in High Pressure Optical Pumping Experiments

We present measurements, using two complementary methods, of the breakdown of atomic angular momentum selection rules in He-broadened Rb vapor. Atomic dark states are rendered weakly absorbing due to fine-structure mixing during Rb-He collisions. The effect substantially increases the photon demand for optical pumping of dense vapors

Astrometric-spectroscopic determination of the absolute masses of the HgMn binary star Phi Herculis

The Mercury-Manganese star Phi Her is a well known spectroscopic binary that has been the subject of a recent study by Zavala et al. (2006), in which they resolved the companion using long-baseline interferometry. The total mass of the binary is now fairly well established, but the combination of the spectroscopy with the astrometry has not resulted in individual masses consistent with the spectral types of the components. The motion of the center of light of Phi Her was clearly detected by the Hipparcos satellite. Here we make use of the Hipparcos intermediate data (`abscissa residuals') and show that by combining them in an optimal fashion with the interferometry the individual masses can be obtained reliably using only astrometry. We re-examine and then incorporate existing radial-velocity measurements into the orbital solution, obtaining improved masses of 3.05 +/- 0.24 M_Sun and 1.614 +/- 0.066 M_Sun that are consistent with the theoretical mass-luminosity relation from recent stellar evolution models. These mass determinations provide important information for the understanding of the nature of this peculiar class of stars.Comment: Total of 18 pages including figures and tables, in emulateapj format. To appear in The Astronomical Journal, June 2007 issu

Evidence of clonal budding in a radial cluster of Paraconularia crustula (White) (Pennsylvanian: ?Cnidaria)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73153/1/j.1502-3931.1992.tb01645.x.pd

Buffalo National River Ecosystems - Part II

The priorities were established for the Buffalo National River Ecosystem Studies through meetings and correspondence with Mr. Roland Wauer and other personnel of the Office of Natural Sciences, Southwest Region of the National Park Service. These priorities were set forth in the appendix of contract no. CX 700050443 dated May 21, 1975

Pattern selection as a nonlinear eigenvalue problem

A unique pattern selection in the absolutely unstable regime of driven, nonlinear, open-flow systems is reviewed. It has recently been found in numerical simulations of propagating vortex structures occuring in Taylor-Couette and Rayleigh-Benard systems subject to an externally imposed through-flow. Unlike the stationary patterns in systems without through-flow the spatiotemporal structures of propagating vortices are independent of parameter history, initial conditions, and system length. They do, however, depend on the boundary conditions in addition to the driving rate and the through-flow rate. Our analysis of the Ginzburg-Landau amplitude equation elucidates how the pattern selection can be described by a nonlinear eigenvalue problem with the frequency being the eigenvalue. Approaching the border between absolute and convective instability the eigenvalue problem becomes effectively linear and the selection mechanism approaches that of linear front propagation. PACS: 47.54.+r,47.20.Ky,47.32.-y,47.20.FtComment: 18 pages in Postsript format including 5 figures, to appear in: Lecture Notes in Physics, "Nonlinear Physics of Complex Sytems -- Current Status and Future Trends", Eds. J. Parisi, S. C. Mueller, and W. Zimmermann (Springer, Berlin, 1996

Charon's radius and density from the combined data sets of the 2005 July 11 occultation

The 2005 July 11 C313.2 stellar occultation by Charon was observed by three separate research groups, including our own, at observatories throughout South America. Here, the published timings from the three data sets have been combined to more accurately determine the mean radius of Charon: 606.0 +/- 1.5 km. Our analysis indicates that a slight oblateness in the body (0.006 +/- 0.003) best matches the data, with a confidence level of 86%. The oblateness has a pole position angle of 71.4 deg +/- 10.4 deg and is consistent with Charon's pole position angle of 67 deg. Charon's mean radius corresponds to a bulk density of 1.63 +/- 0.07 g/cm3, which is significantly less than Pluto's (1.92 +/- 0.12 g/cm3). This density differential favors an impact formation scenario for the system in which at least one of the impactors was differentiated. Finally, unexplained differences between chord timings measured at Cerro Pachon and the rest of the data set could be indicative of a depression as deep as 7 km on Charon's limb.Comment: 25 pages including 4 tables and 2 figures. Submitted to the Astronomical Journal on 2006 Feb 0

Inelastic Proton‐Proton Scattering at Very High Energy

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87855/2/99_1.pd

Final Report: Buffalo National River Ecosystems

The objective of this study was to sample the Buffalo River on a seasonal basis for a year, in order to determine whether any potential water quality problems existed