Experimental Investigation of Radar Cross Section Spatial Correlation Properties for a Point Scattering Target

This research investigates the spatial correlation of RCS. In pulsed radar systems, probability of detection for partially correlated signals depends on the autocovariance of the target\u27s RCS. The RCS changes pulse to pulse due to spatial and time fluctuations. Spatial fluctuation are due to the motion of all scatterers relative to the radar (i.e. changing aspect angle). Time fluctuations are due to relative motion of scatterers to each other (i.e. wings flexing, engines spinning). Theory developed at AFIT [9] can generate autocovariance estimates from a distribution of scatterers. Theory based autocovariance estimates are compared to static measurement based autocovariance estimates in order to validate this theory. Interaction among scatterers is the most significant source of deviation between theory and measurement based autocovariance estimates

For good work do they wish to kill him?: narrative critique of the Acts of Pilte

Includes bibliographical references.Thesis (M.A.) University of Missouri-Columbia 2006.Title from title screen of research.pdf file (viewed on August 28, 2007)The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Dissertations, Academic -- University of Missouri--Columbia -- Religious studies.The Acts of Pilate, preserved today in two Greek versions, a Latin version, a Coptic, an Armenian, and an Old Slavic version, is regarded as one of the most popular and widely circulated apocrypha from late antiquity and medieval literature. Previous generations of scholars have believed this narrative to be a product of the literary trend from early Christian writings vilifying ethnic Jews for the trial and death of Jesus. However, this text is more complex and more nuanced than previously recognized by scholars. Although this text is suggestive of a literary trend popular among Christian writers slandering Jews for the crucifixion of Jesus, it is distinctive in this tradition because this narrative offers the high priests, the antagonist held accountable for the death of Jesus in other literary sources, as the narrative's main characters. Furthermore, the narrative's plot is to convince this protagonist of the miracles and ascension of Jesus, and the narrative's conflict is the high priests' resistance and inability to refute these testimonials. This evidence is offered by characters of indisputable integrity, which are also Jewish. Through actors such as Nicodemus, three teachers from the Galilee, a council member named Levi, and even the miracle of Joseph's disappearance from his imprisonment, the narrative's protagonists remain unmoved regardless of the seemingly undeniable evidence. Finally, the choice of these figures as the narrative's obstinate protagonist in light of testimonials from Jewish characters suggests a possible social situation related to the composition of this form of the text and offers an insight into a possible date for the origin of this text

Quenching of dynamic nuclear polarization by spin-orbit coupling in GaAs quantum dots

The central-spin problem, in which an electron spin interacts with a nuclear spin bath, is a widely studied model of quantum decoherence. Dynamic nuclear polarization (DNP) occurs in central spin systems when electronic angular momentum is transferred to nuclear spins and is exploited in spin-based quantum information processing for coherent electron and nuclear spin control. However, the mechanisms limiting DNP remain only partially understood. Here, we show that spin-orbit coupling quenches DNP in a GaAs double quantum dot, even though spin-orbit coupling in GaAs is weak. Using Landau-Zener sweeps, we measure the dependence of the electron spin-flip probability on the strength and direction of in-plane magnetic field, allowing us to distinguish effects of the spin-orbit and hyperfine interactions. To confirm our interpretation, we measure high-bandwidth correlations in the electron spin-flip probability and attain results consistent with a significant spin-orbit contribution. We observe that DNP is quenched when the spin-orbit component exceeds the hyperfine, in agreement with a theoretical model. Our results shed new light on the surprising competition between the spin-orbit and hyperfine interactions in central-spin systems.Comment: 5+12 pages, 9 figure

Automated real time constant-specificity surveillance for disease outbreaks

<p>Abstract</p> <p>Background</p> <p>For real time surveillance, detection of abnormal disease patterns is based on a difference between patterns observed, and those predicted by models of historical data. The usefulness of outbreak detection strategies depends on their specificity; the false alarm rate affects the interpretation of alarms.</p> <p>Results</p> <p>We evaluate the specificity of five traditional models: autoregressive, Serfling, trimmed seasonal, wavelet-based, and generalized linear. We apply each to 12 years of emergency department visits for respiratory infection syndromes at a pediatric hospital, finding that the specificity of the five models was almost always a non-constant function of the day of the week, month, and year of the study (<it>p </it>< 0.05). We develop an outbreak detection method, called the expectation-variance model, based on generalized additive modeling to achieve a constant specificity by accounting for not only the expected number of visits, but also the variance of the number of visits. The expectation-variance model achieves constant specificity on all three time scales, as well as earlier detection and improved sensitivity compared to traditional methods in most circumstances.</p> <p>Conclusion</p> <p>Modeling the variance of visit patterns enables real-time detection with known, constant specificity at all times. With constant specificity, public health practitioners can better interpret the alarms and better evaluate the cost-effectiveness of surveillance systems.</p

Maximum Entropy Reconstruction of the Interstellar Medium: I. Theory

We have developed a technique to map the three-dimensional structure of the local interstellar medium using a maximum entropy reconstruction technique. A set of column densities N to stars of known distance can in principle be used to recover a three-dimensional density field n, since the two quantities are related by simple geometry through the equation N = C n, where C is a matrix characterizing the stellar spatial distribution. In practice, however, there is an infinte number of solutions to this equation. We use a maximum entropy reconstruction algorithm to find the density field containing the least information which is consistent with the observations. The solution obtained with this technique is, in some sense, the model containing the minimum structure. We apply the algorithm to several simulated data sets to demonstrate its feasibility and success at recovering ``real'' density contrasts. This technique can be applied to any set of column densities whose end points are specified. In a subsequent paper we shall describe the application of this method to a set of stellar color excesses to derive a map of the dust distribution, and to soft X-ray absorption columns to hot stars to derive a map of the total density of the interstellar medium.Comment: 23 pages, 7 fig.; accepted for publication in the Ap.

Recovery of the Decorin-Enriched Fraction, Extract (D), From Human Skin: An Accelerated Protocol

The original extraction procedure of Engel and Catchpole [1] has often been used to recover decorin-enriched material from the skin. This material has a strong inhibitory effect on fibroblast proliferation, and clearly suppresses it in skin except after the first 5–6 days of wounding when new scaffold material is required. The aim of our present study has been to find and evaluate the product of a faster recovery method, and to check its consistency as a more reliable means of regularly obtaining sufficient material for topical application in wounds that might become hypertrophic. Modifications of the original Toole and Lowther [2] extraction procedure have been carefully evaluated in an attempt to cut preparation time without compromising biological activity of the inhibitory extract. We have devised a faster recovery procedure without compromising biological activity, even if initial recovery has been somewhat reduced. The latter problem could be offset by repeated cycles of the final extraction step. The main inhibitory activity is shown to be within the decorin-enriched “extract D,” as the core protein and DSPG II. Adjustment of the extract towards neutrality after dialysis against water keeps most of the extracted protein in solution and yielded a decorin-enriched preparation that had a specific activity equivalent to that of the old method. It also yielded a fraction that was readily lyophilised to give a small amount of material that could be stored indefinitely without loss of activity and readily redissolved in aqueous solution. A reliable and relatively quick method is presented for the production, from human skin, of a decorin-enriched preparation that has strong fibroblast inhibitory action. The value of the procedure is that it is inexpensive and can produce the quantities that might be used topically in reducing hypertrophic scarring of wounds