Transmission Lines and Meta-Materials based on Quantum Hall Plasmonics

The characteristic impedance of a microwave transmission line is typically constrained to a value $Z_0$ = 50 $\Omega$, in-part because of the low impedance of free space and the limited range of permittivity and permeability realizable with conventional materials. Here we suggest the possibility of constructing high-impedance transmission lines by exploiting the plasmonic response of edge states associated with the quantum Hall effect in gated devices. We analyze various implementations of quantum Hall transmission lines based on distributed networks and lumped-element circuits, including a detailed account of parasitic capacitance and Coulomb drag effects, which can modify device performance. We additionally conceive of a meta-material structure comprising arrays of quantum Hall droplets and analyze its unusual properties. The realization of such structures holds promise for efficiently wiring-up quantum circuits on chip, as well as engineering strong coupling between semiconductor qubits and microwave photons

Morals From Rationality Alone? Some Doubts

Contractarians aim to derive moral principles from the dictates of instrumental rationality alone. But it is well-known that contractarian moral theories struggle to identify normative principles that are both uniquely rational and morally compelling. Michael Moehler's recent book, *Minimal Morality* seeks to avoid these difficulties by developing a novel "two-level" social contract theory, which restricts the scope of contractarian morality to cases of deep and persistent moral disagreement. Yet Moehler remains ambitious, arguing that a restricted version of Kant's categorical imperative is a uniquely rational principle of conflict resolution. We develop a formal model of Moehler's informal game-theoretic argument, which reconstructs a valid argument for Moehler's conclusion. This model, in turn, enables us to expose how a successful argument for Moehler's contractarian principle rests on assumptions that can only be justified by subtle yet significant departures from the standard conception of rationality. We thus extend our understanding of familiar contractarian difficulties by showing how they arise even if we restrict the scope of contractarian morality to a domain where its application seems both promising and necessary. We show that the problem lies not in contractarians' immodest ambitions but in the modest resources rationality can offer to satisfy them

The Impact of Contaminated RR Lyrae/Globular Cluster Photometry on the Distance Scale

RR Lyrae variables and the stellar constituents of globular clusters are employed to establish the cosmic distance scale and age of the universe. However, photometry for RR Lyrae variables in the globular clusters M3, M15, M54, M92, NGC2419, and NGC6441 exhibit a dependence on the clustercentric distance. For example, variables and stars positioned near the crowded high-surface brightness cores of the clusters may suffer from photometric contamination, which invariably affects a suite of inferred parameters (e.g., distance, color excess, absolute magnitude, etc.). The impetus for this study is to mitigate the propagation of systematic uncertainties by increasing awareness of the pernicious impact of contaminated and radial-dependent photometry.Comment: To appear in ApJ

Children at risk : their phonemic awareness development in holistic instruction

Includes bibliographical references (p. 17-19

Estimating Percent Residue Cover Using the Line-Transect Method

Leaving crop residue on the soil surface is one of the easiest and most cost-effective methods of reducing soil erosion. Research in Nebraska and other midwestern states has shown that leaving as little as 20 percent of the soil surface covered with crop residue can reduce soil erosion by one-half of what it would be from residue-free conditions. Greater amounts of residue cover will further reduce erosion. Many Conservation Plans specify crop residue management or residue left on the soil surface as the primary erosion control method. Generally, the amount of cover required after planting ranges from 30 percent to as much as 85 percent. Thus, it is important to accurately determine percent residue cover to verify effective erosion control and compliance with a Conservation Plan. Residue cover cannot be estimated merely by looking across a field. Such estimates, often attempted from the road or edge of the field, grossly overestimate the actual amount of cover. Accurate estimates of residue cover can only be obtained from measurements taken within the field, while looking straight down at the soil and residue. Crop residue management, or leaving residue on the soil surface, is the most cost-effective method of reducing soil erosion available to Nebraska farmers. Accurate measurements of percent residue cover are needed to determine if enough cover is present to adequately reduce erosion and to comply with a Conservation Plan. The line-transect method is one of the easiest and most accurate methods of determining percent residue cover

The Effects of Surface Disturbances on the Leaching of Heavy Metals

The harmful effects of heavy metal contamination of surface waters impacted by gold mining activity are well documented. An examination was conducted on the effects of surface disturbances in Wade Creek on the concentrations of heavy metals in solution, and whether Thiobacillus ferrooxidans, a bacteria found in heavy metal contaminated drainages from placer mines, is found in the drainage. Thiobacillus ferrooxidans was not detected in this particular setting. The effects of mining activity and relandscaping of stockpiled tailings showed in a short distance, a net increase of dissolved arsenic, copper, zinc, and iron. However, the long distance impact of dissolved metals was minimal. Generally, it seems that the dampening of the total suspended solids had a direct effect on the removal of metals dissolved in solution.The research on which the report is based was financed in part by the United States Department of the Interior, Geological Survey, through grant number 14-08-0001-61313 to the Water Research Center

Intake Ground Vortex Prediction Methods

For an aircraft turbofan engine in ground operations or during the take-off run a ground vortex can occur which is ingested and could potentially adversely affect the engine performance and operation. The vortex characteristics depend on the ground clearance, intake flow capture ratio and the relative wind vector. It is a complex flow for which there is currently very little appropriate quantitative preliminary design information. These aspects are addressed in this work where a range of models are developed to provide a method for estimating the key metrics such as the formation boundary and the ground vortex size and strength. Three techniques are presented which utilize empirical, analytical and semi-empirical approaches. The empirical methods are primarily based on a large dataset of model-scale experiments which quantitatively measured the ground vortex characteristics for a wide range of configurations. These include the effects of intake ground clearance, approaching boundary layer thickness, intake Mach number and capture velocity ratio. Overall the models are able to predict some of the key measured behaviours such as the velocity ratio for maximum vortex strength. With increasing empiricism for key sub-elements of the model construction, an increasing level of agreement is found with the experimental results. Overall the three techniques provide a relatively quick and easy method in establishing the important vortex characteristics for a given headwind configuration which is of significant use from a practical engineering perspective

Coupled ocean–atmosphere interactions between the Madden–Julian oscillation and synoptic-scale variability over the warm pool

A principal component analysis of the combined fields of sea surface temperature (SST) and surface zonal and meridional wind reveals the dominant mode of intraseasonal (30-70-day) co-variability during northern winter in the tropical Eastern Hemisphere is that of the Madden-Julian Oscillation (MJO). Regression calculations show that the submonthly (30-day high-pass filtered) surface wind variability is significantly modulated during the MJO. Regions of increased (decreased) submonthly surface wind variability propagate eastward, approximately in phase with the intraseasonal surface westerly (easterly) anomalies of the MJO. Due to the dependence of the surface latent heat flux on the magnitude of the total wind speed, this systematic modulation of the submonthly surface wind variability produces a significant component in the intraseasonal latent heat flux anomalies, which partially cancels the latent heat flux anomalies due to the slowly varying intraseasonal wind anomalies, particularly south of 10S. A method is derived that demodulates the submonthly surface wind variability from the slowly varying intraseasonal wind anomalies. This method is applied to the wind forcing fields of a one-dimensional ocean model. The model response to this modified forcing produces larger intraseasonal SST anomalies than when the model is forced with the observed forcing over large areas of the southwest Pacific Ocean and southeast Indian Ocean during both phases of the MJO. This result has implications for accurate coupled modeling of the MJO. A similar calculation is applied to the surface shortwave flux, but intraseasonal modulation of submonthly surface shortwave flux variability does not appear to be important to the dynamics of the MJO