Sea Surface Salinity Retrievals from Aquarius Using Neural Networks

Even though the Sea Surface Salinity (SSS) retrieved from Aquarius are generally very close to in-situ measurements, the level of similarity varies with the region and with the circumstances of the observations (wind speed, sea surface temperature, etc.). SSS is currently retrieved from the brightness temperatures measured by Aquarius and applying the current theoretical model for the propagation and emission of the natural thermal radiation. In this contribution we consider an alternative retrieval approach based on a Neural Network (NN) with the goal of improving the subsets of Aquarius SSS data that are in poorer agreement within-situ measurements. The subset considered here are the SSS retrieved at latitudes higher than 30 . The output of the NN approach are compared against in-situ measurements using four statistical metrics (correlation coefficient, bias, RMSD and 5% trimmed range). The output of the NN and the nominal Aquarius SSS are compared against SSS values from in-situ measurements and from ocean models. From these comparisons it appears that the output of the NN matches the in-situ measurements better than the nominal Aquarius SSS

Markers typed in genome-wide analysis identify regions showing deviation from Hardy-Weinberg equilibrium

<p>Abstract</p> <p>Background</p> <p>Deviations from Hardy-Weinberg equilibrium (HWE) are commonly thought of as indicating genotyping errors, population stratification or some other artefact. However they could also arise through important biological mechanisms. In particular, genetic variants having a recessive effect on the successful fertilisation and/or development of an embryo might be manifest through such deviations in an unselected sample of "control" subjects.</p> <p>Findings</p> <p>We investigated genotypes from 463842 autosomal markers from 1504 British subjects. We identified regions in which several neighbouring markers exhibited deviation from HWE in the same direction by considering "heterozygosity scores" in windows of 10 markers. The heterozygosity score for each marker was defined as -log(p) or log(p) according to whether the marker demonstrated increased heterozygosity or homozygosity. In each window the marker with the highest absolute score was ignored and the positive and negative scores were summed for the other nine markers. Windows were selected on the basis of this sum exceeding a given threshold, for which we used values of 50 or 15.</p> <p>For the threshold of 50, we identified 7 regions with increased heterozygosity and for the threshold of 15 we identified 22 regions with increased heterozygosity, 23 with increased homozygosity and 2 containing both kinds of window. The most impressive of these results came from a group of 6 markers at 17q21, each of which showed increased heterozygosity significant at p < 10^-190.</p> <p>Conclusion</p> <p>The human genome contains regions which deviate markedly from HWE and these might harbour genes influencing embryonic survival.</p

Racial and Ethnic Studies, Political Science and Mid-Wifery

One of the major fallacies of Western civilization, according to Alfred North Whitehead,\u27 was the propensity of Western thinkers to assume that ideas generated within their intellectual landscape were indicative of reality itself. Although some phases of Western science, notably physics and philosophy, have transcended their parochial origins, aspects of the old medieval synthesis still remain in the Western worldview. The gradual fragmentation of the old categories of natural history and theology into the isolated sciences and disciplines of today has produced a myriad of separate bodies of knowledge complete with their professional priesthoods and has allowed considerable slippage in the ability of the Western scientific paradigm to generate adequate explanations for the multitude of problems we face as a society

Tribes, Treaties, and Constitutional Tribulations

Federal Indian law... is a loosely related collection of past and present acts of Congress, treaties and agreements, executive orders, administrative rulings, and judicial opinions, connected only by the fact that law in some form has been applied haphazardly to American Indians over the course of several centuries.... Indians in their tribal relation and Indian tribes in their relation to the federal government hang suspended in a legal wonderland. In this book, two prominent scholars of American Indian law and politics undertake a full historical examination of the relationship between Indians and the United States Constitution that explains the present state of confusion and inconsistent application in U.S. Indian law. The authors examine all sections of the Constitution that explicitly and implicitly apply to Indians and discuss how they have been interpreted and applied from the early republic up to the present. They convincingly argue that the Constitution does not provide any legal rights for American Indians and that the treaty-making process should govern relations between Indian nations and the federal government.https://scholarship.richmond.edu/bookshelf/1331/thumbnail.jp

[Introduction to] The Legal Universe: Observations on the Foundations of American Law

According to Deloria and Wilkins, Whenever American minorities have raised voices of protest, they have been admonished to work within the legal system that seek its abolition. This essential work examines the historical evolution of the legal rights of various minority groups and the relationship between these rights and the philosophical intent of the American founders.https://scholarship.richmond.edu/bookshelf/1336/thumbnail.jp

Measuring Johnson resistor noise in non-equilibrium conditions

In 1916, Einstein postulated the existence of gravitational waves in his General Theory of Relativity. Gravitational waves are described as ripples in the curvature of spacetime detected using laser interferometers to measure the quadrupole stretching and squeezing of space caused by these waves. Current detectors are limited by thermal noise which is calculated using the Fluctuation Dissipation Theory (FDT). A number of future detectors are planned to operate at cryogenic temperatures to reduce this thermal noise but it introduces some issues to address. The FDT relies on the system it is describing being in thermal equilibrium. For room temperature detectors, any thermal gradient present is significantly smaller than the absolute temperature and so thermal equilibrium can be assumed. In cryogenic detectors there will be substantial thermal gradients due to heat being removed through the suspension fibres and the system can no longer be seen to be in equilibrium. The experiment described in this thesis investigates the validity of the FDT when a system is in non-equilibrium. By measuring Johnson noise in a thin film platinum resistor while under the effect of a thermal gradient, the thermal noise that is predicted by the FDT can be compared with the measured thermal noise of the resistor, to look for any deviation from the theoretical values. The experiment showed a nul result where no excess noise was seen at an absolute temperature of 110k with a temperature difference of 6k across the resistor. This provides a limiting factor for the thermal gradient that will not produce excess noise above the theoretically calculated value, and giving a limit to the thermal gradient where the FDT is still valid

Pump-probe differencing technique for cavity-enhanced, noise-canceling saturation laser spectroscopy

We present an experimental technique enabling mechanical-noise free, cavity-enhanced frequency measurements of an atomic transition and its hyperfine structure. We employ the 532nm frequency doubled output from a Nd:YAG laser and an iodine vapour cell. The cell is placed in a traveling-wave Fabry-Perot interferometer (FPI) with counter-propagating pump and probe beams. The FPI is locked using the Pound-Drever-Hall (PDH) technique. Mechanical noise is rejected by differencing pump and probe signals. In addition, this differenced error signal gives a sensitive measure of differential non-linearity within the FPI.Comment: 3 pages, 5 figures, submitted to Optics Letter