Studies of Ground Conductivity in the Territory of Alaska

The effective ground conductivity of Alaska has been determined by a comparison of experimental and theoretical field strengths. The experimental field strengths have been obtained by use of an airborne receiver, flown along radial paths from a large number of CAA radio ranges and beacons. The surface wave attenuation factor was computed for both a plane and a curved, homogeneous earth by methods presented by Norton. The experimentally determined relative field strengths were plotted as a function of distance and were compared with a family of curves for assumed values of conductivity and dielectric constant. From this comparison, that value of conductivity that best fits the experimental data is taken as the effective conductivity over the path. An investigation of the effect at dielectric constant on the transmitted signal shows that, within the frequency range used, a change of dielectric constant from 1 to 20 has but little effect on the attenuation of the transmitted signal for values of conductivity between 1 and 5 mmho/m. The experimental results indicate that for most sections of Alaska, the effective conductivity falls within this range. In some cases the earth was not homogeneous over the entire flight path as evidenced by changes in the slope of the field strength vs distance curves. In such cases, the data were replotted with an initial point at the discontinuity and new theoretical curves were drawn for each section of the field strength vs distance curves. Investigation of the variation of effective conductivity with change of frequency and at different seasons was made. In addition, wave tilt methods of determining the conductivity were used. A 'Ground Constants Measuring Set' was obtained from the Signal Corps and measurements were made in selected areas in Alaska. Attempts were made to use 1height-gain' and 'mutual coupling of loops' techniques but these were not successful. An investigation of anomolous propagation in the vicinity of Point Barrow was made. It was determined that this anomolous propagation appears to be the result of a layered earth. In addition to the anomolous propagation in the vicinity of Point Barrow, there appears to be similar anomolies in the vicinity of Kotzebue, Galena, Bethel and Port Heiden. From the above investigations a map showing the effective conductivity of Alaska as determined by the attenuation method is presented.Navy Department Bureau of Ships NObsr 72528 NE 120308 Subtask No. 6ABSTRACT -- PART I A. Purpose -- B. General Factual Data -- C. Detail Factual Data -- PART II -- A, Conclusions -- APPENDIX IYe

Magnetic microspherules associated with the K/T and upper Eocene extinction events

Magnetic microspherules were identified in over 20 K/T boundary sites, and in numerous Deep Sea Drilling Project (DSDP) cores from the Caribbean and Pacific, synchronous with the extinction of several radiolarian species near the end of the Eocene. The K/T magnetic spherules are of particular interest as carriers of Ir and other siderophiles generally found in abundance in K/T boundary clay. Furthermore the textures and unusual chemistry of their component magnetic phases indicate an origin at high temperature, possibly related to (an) unusual event(s) marking the end of the Cretaceous and Eocene periods. Their origin, along with the non-magnetic (sanidine) spheules, is generally ascribed directly to megaimpact events hypothesized to have periodically disrupted life on Earth. A survey of microspherical forms associated with known meteorite and impact derived materials reveals fundamental differences from the extinction related spherules. Low temperature magnetic experiments on the K/T and Upper Eocene spheroids indicate that, unlike tektites, extremely small superparamagnetic carriers are not present in abundance. The extensive subaerial exposure of Cretaceous combustible black shale during sea level regression in the latest Cretaceous represents a potential source for the magnetic spheroids found in certain K/T boundary clays. The recent discovery of high Ir abundances distributed above and below the K/T boundary within shallow water sediments in Israel, which also contain the most extensive known zones of combustion metamorphism, the so called Mottled Zone, adds a further dramatic footnote to the proposed association between the magnetic spheroids and combustion of organic shales. Interestingly, the Mottled Zone also contains the rare mineral magnesioferrite, which was identified both within the K/T magnetic spheroids and as discrete crystals in boundary clay from marine and continental sites

SCAN DATA RESEARCH: THE STATUS

Research Methods/ Statistical Methods,

Method for analyzing radiation sensitivity of integrated circuits

A method for analyzing the radiation sensitivity of an integrated circuit is described to determine the components. The application of a narrow radiation beam to portions of the circuit is considered. The circuit is operated under normal bias conditions during the application of radiation in a dosage that is likely to cause malfunction of at least some transistors, while the circuit is monitored for failure of the irradiated transistor. When a radiation sensitive transistor is found, then the radiation beam is further narrowed and, using a fresh integrated circuit, a very narrow beam is applied to different parts of the transistor, such as its junctions, to locate the points of greatest sensitivity

A Consistent Histogram Estimator for Exchangeable Graph Models

Exchangeable graph models (ExGM) subsume a number of popular network models. The mathematical object that characterizes an ExGM is termed a graphon. Finding scalable estimators of graphons, provably consistent, remains an open issue. In this paper, we propose a histogram estimator of a graphon that is provably consistent and numerically efficient. The proposed estimator is based on a sorting-and-smoothing (SAS) algorithm, which first sorts the empirical degree of a graph, then smooths the sorted graph using total variation minimization. The consistency of the SAS algorithm is proved by leveraging sparsity concepts from compressed sensing.Comment: 28 pages, 5 figure

The propagator for the step potential using the path decomposition expansion

We present a direct path integral derivation of the propagator in the presence of a step potential. The derivation makes use of the Path Decomposition Expansion (PDX), and also of the definition of the propagator as a limit of lattice paths.Comment: To appear in DICE 2008 conference proceeding

Germinal Epithelium Cytology during Spermatogenesis in the Alligator Snapping Turtle, Macrochelys temminckii (Reptilia: Chelydridae)

We investigated the cytology of the seminiferous epithelia of the Alligator Snapping Turtle (Macrochelys temminckii). Spermatogenic and regressed testes were assessed from 2 adult individuals collected in Arkansas in May and September of 1993. Specifically, we focused on the cellular phases of germ cell development and maturation. The germ cell morphology and developmental strategy within the germinal epithelium of M. temminckii appear similar to that of other genera of turtles previously studied. Interestingly, mitotic, meiotic, and spermiogeneic cells are nearly identical to that of other turtles studied based on light microscopy. There are also 6 recognizable steps to spermiogenesis, which is slightly different than the 7 steps of most turtles (step 7 absent). Though this study only uses 2 individuals (because of its endangered status), M. temminckii appears to start spermatogenesis in the spring, and the climax of spermiogenesis occurs in the fall similar to that of other temperate turtles studied to date based on light microscopy. Peculiar to both turtles in this study were the regular appearance of very large germ cells in the basal compartment of the germinal epithelium. Based on previous research and our histological analysis these enlarged spermatogonia exhibit hypertrophic characteristics typical of cells undergoing apoptosis

A program downloader and other utility software for the DATAC bus monitor unit

A set or programs designed to facilitate software testing on the DATAC Bus Monitor is described. By providing a means to simplify program loading, firmware generation, and subsequent testing of programs, the overhead involved in software evaluation is reduced and that time is used more productively in performance, analysis and improvement of current software

Evidence of improved inventory control

Inventory data applied to a standard partial stock-adjustment model demonstrate that inventory control, defined by desired marginal inventory-sales ratios and speeds of adjustment, improved in the last decade or so, particularly in the manufacturing sector. In addition, the evidence suggests that, contrary to popular wisdom, the net effect of these changes in inventory control has been to increase the volatility of inventory investment in both the manufacturing and trade sectors.Inventories

Returns, Lags, and Complementarities in Brand and Generic Advertising: The Demand for Peanut Butter

This paper estimates the impact of generic and brand advertising on the demand for peanut butter in the U.S. An error correction model is estimated with quarterly data from 1985 to 2004 to study both the short- and long-run adjustments. The results indicate that brand advertising has a significant but short-lived effect on aggregate consumption while generic advertising has little short-run but significant long-run effects.Demand and Price Analysis, Marketing,