Overview of Geotechnical Issues Involved in the Olmsted Locks and Dam Project

The Olmsted Locks and Dam project consists of new twin 1200-foot locks and dam located on the Ohio River near its confluence with the Mississippi River. The site of the locks and dam presents some unique geotechnical challenges. A major landslide on the Illinois bank, artesian groundwater conditions, significant seismic considerations, and the design of the pile foundation and the construction cofferdams presented major challenges to the design engineers. The geotechnical investigations and the design considerations involved in this project are discussed

Vol. 1 Ch. 8 A Small Deposit of Copper Artifacts at Seip

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Background Principles, Takings, and Libertarian Property: A Reply to Professor Huffman

One of the principal, if unexpected, results of the Supreme Court\u27s 1992 decision in Lucas v. South Carolina Coastal Commission is the rise of background principles of property and nuisance law as a categorical defense to takings claims. Our writings on the background principles defense have provoked Professor Huffman, a devoted advocate for an expanded use of regulatory takings to protect landowner development rights, to mistakenly charge us with arguing for the use of common law principles to circumvent the rule of law, Supreme Court intent, and the takings clause. Actually, ours was not a normative brief at all, but instead a positivistic explanation of takings cases in the lower courts since Lucas, which include judicial recognition of statutory background principles. In this article, we respond to Huffman, examining the continuing importance of the background principles defense and explaining the trouble with his vision of libertarian property and his peculiar notion of the rule of law. We focus especially on wetlands regulation, which Huffman thinks is a recent development when in fact its origins date to medieval England, and therefore is particularly suited to the background principles defense. We conclude that background principles, as the logically antecedent inquiry into the nature of a claimant\u27s property interest, are now a permanent feature of the takings landscape

Focusing of Intense Subpicosecond Laser Pulses in Wedge Targets

Two dimensional particle-in-cell simulations characterizing the interaction of ultraintense short pulse lasers in the range 10^{18} \leq I \leq 10^{20} W/cm^{2} with converging target geometries are presented. Seeking to examine intensity amplification in high-power laser systems, where focal spots are typically non-diffraction limited, we describe key dynamical features as the injected laser intensity and convergence angle of the target are systematically varied. We find that laser pulses are focused down to a wavelength with the peak intensity amplified by an order of magnitude beyond its vacuum value, and develop a simple model for how the peak location moves back towards the injection plane over time. This performance is sustained over hundreds of femtoseconds and scales to laser intensities beyond 10^{20} W/cm^{2} at 1 \mu m wavelength.Comment: 5 pages, 6 figures, accepted for publication in Physics of Plasma

Missing links in the study of solute and particle exchange between the sea floor and water column

Exchanges of solutes and solids between the sea floor and water column are a vital component of ecosystem functioning in marine habitats around the globe. This review explores particle and solute exchange processes, the different mechanisms through which they interact at the ecosystem level, as well as their interdependencies. Solute and particle exchange processes are highly dependent on the characteristics of the environment within which they takes place. Exchange is driven directly by a number of factors, such as currents, granulometry, nutrient, and matter inputs, as well as living organisms. In turn, the occurrence of exchanges can influence adjacent environments and organisms. Major gaps in the present knowledge include the temporal and spatial variation in many of the processes driving benthic/pelagic exchange processes and the variability in the relative importance of individual processes caused by this variation. Furthermore, the accurate assessment of some anthropogenic impacts is deemed questionable due to a lack of baseline data and long-term effects of anthropogenic actions are often unknown. It is suggested that future research should be transdisciplinary and at ecosystem level wherever possible and that baseline surveys should be implemented and long-term observatories established to fill the current knowledge gaps

Impact of reionization on CMB polarization tests of slow-roll inflation

Estimates of inflationary parameters from the CMB B-mode polarization spectrum on the largest scales depend on knowledge of the reionization history, especially at low tensor-to-scalar ratio. Assuming an incorrect reionization history in the analysis of such polarization data can strongly bias the inflationary parameters. One consequence is that the single-field slow-roll consistency relation between the tensor-to-scalar ratio and tensor tilt might be excluded with high significance even if this relation holds in reality. We explain the origin of the bias and present case studies with various tensor amplitudes and noise characteristics. A more model-independent approach can account for uncertainties about reionization, and we show that parametrizing the reionization history by a set of its principal components with respect to E-mode polarization removes the bias in inflationary parameter measurement with little degradation in precision.Comment: 9 pages, 6 figures; submitted to Phys. Rev.