Teaching A Pronunciation Problem

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98361/1/j.1467-1770.1962.tb01252.x.pd

Optimal time decay of the non cut-off Boltzmann equation in the whole space

In this paper we study the large-time behavior of perturbative classical solutions to the hard and soft potential Boltzmann equation without the angular cut-off assumption in the whole space \threed_x with \DgE. We use the existence theory of global in time nearby Maxwellian solutions from \cite{gsNonCutA,gsNonCut0}. It has been a longstanding open problem to determine the large time decay rates for the soft potential Boltzmann equation in the whole space, with or without the angular cut-off assumption \cite{MR677262,MR2847536}. For perturbative initial data, we prove that solutions converge to the global Maxwellian with the optimal large-time decay rate of O(t^{-\frac{\Ndim}{2}+\frac{\Ndim}{2r}}) in the L^2_\vel(L^r_x)-norm for any $2\leq r\leq \infty$.Comment: 31 pages, final version to appear in KR

Perceptions of Technology Use and Its Effects on Student Writing

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Electroreduction and photometric detection of low-level uranium in aqueous Purex solutions. Consolidated Fuel-Reprocessing Program

During proper operation of the Purex process for the recovery of uranium and plutonium from spent reactor fuel, there are only trace levels of uranium in the aqueous waste. In the event of an upset in the extraction columns the aqueous waste stream would give the first indication of breakthrough. From the standpoint of process control it would be desirable to have an in-line, real-time sensor for uranium in the aqueous waste stream. It was toward this end that this investigation was undertaken. The measurement technique that seems to provide the most sensitive method without addition of reagents appears to be the electrochemical reduction of UO{sub 2}{sup 2+} to U(IV) followed by spectral measurement. The electrochemical reduction to U(IV) increases the sensitivity by a factor of three to five and shifts the measurement wavelength to a spectral area (647 nm and 1075 nm) unaffected by fission products. Using the proposed analysis sequence it is possible to determine uranium at a level of 0.2 g/L in the presence of relatively high spectral background. This report details the electrochemical reduction of U(VI) in nitric acid solutions (0.5 M to 2.0 M) with platinum-vitreous carbon electrodes and examines the spectral behavior of U(IV) as a function of nitric acid concentration

Control sideband generation for dual-recycled laser interferometric gravitational wave detectors

We present a discussion of the problems associated with generation of multiple control sidebands for length sensing and control of dual-recycled, cavity-enhanced Michelson interferometers and the motivation behind more complicated sideband generation methods. We focus on the Mach–Zehnder interferometer as a topological solution to the problem and present results from tests carried out at the Caltech 40 m prototype gravitational wave detector. The consequences for sensing and control for advanced interferometry are discussed, as are the implications for future interferometers such as Advanced LIGO

TreeToReads - a pipeline for simulating raw reads from phylogenies.

BackgroundUsing phylogenomic analysis tools for tracking pathogens has become standard practice in academia, public health agencies, and large industries. Using the same raw read genomic data as input, there are several different approaches being used to infer phylogenetic tree. These include many different SNP pipelines, wgMLST approaches, k-mer algorithms, whole genome alignment and others; each of these has advantages and disadvantages, some have been extensively validated, some are faster, some have higher resolution. A few of these analysis approaches are well-integrated into the regulatory process of US Federal agencies (e.g. the FDA's SNP pipeline for tracking foodborne pathogens). However, despite extensive validation on benchmark datasets and comparison with other pipelines, we lack methods for fully exploring the effects of multiple parameter values in each pipeline that can potentially have an effect on whether the correct phylogenetic tree is recovered.ResultsTo resolve this problem, we offer a program, TreeToReads, which can generate raw read data from mutated genomes simulated under a known phylogeny. This simulation pipeline allows direct comparisons of simulated and observed data in a controlled environment. At each step of these simulations, researchers can vary parameters of interest (e.g., input tree topology, amount of sequence divergence, rate of indels, read coverage, distance of reference genome, etc) to assess the effects of various parameter values on correctly calling SNPs and reconstructing an accurate tree.ConclusionsSuch critical assessments of the accuracy and robustness of analytical pipelines are essential to progress in both research and applied settings