Compressive and Noncompressive Power Spectral Density Estimation from Periodic Nonuniform Samples

This paper presents a novel power spectral density estimation technique for band-limited, wide-sense stationary signals from sub-Nyquist sampled data. The technique employs multi-coset sampling and incorporates the advantages of compressed sensing (CS) when the power spectrum is sparse, but applies to sparse and nonsparse power spectra alike. The estimates are consistent piecewise constant approximations whose resolutions (width of the piecewise constant segments) are controlled by the periodicity of the multi-coset sampling. We show that compressive estimates exhibit better tradeoffs among the estimator's resolution, system complexity, and average sampling rate compared to their noncompressive counterparts. For suitable sampling patterns, noncompressive estimates are obtained as least squares solutions. Because of the non-negativity of power spectra, compressive estimates can be computed by seeking non-negative least squares solutions (provided appropriate sampling patterns exist) instead of using standard CS recovery algorithms. This flexibility suggests a reduction in computational overhead for systems estimating both sparse and nonsparse power spectra because one algorithm can be used to compute both compressive and noncompressive estimates.Comment: 26 pages, single spaced, 9 figure

A Multiscale Investigation of Habitat Use and Within-river Distribution of Sympatric Sand Darter Species

The western sand darter Ammocrypta clara, and eastern sand darter Ammocrypta pellucida are sand-dwelling fishes of conservation concern. Past research has emphasized the importance of studying individual populations of conservation concern, while recent research has revealed the importance of incorporating landscape scale processes that structure habitat mosaics and local populations. We examined habitat use and distributions of western and eastern sand darters in the lower Elk River of West Virginia. At the sandbar habitat use scale, western sand darters were detected in sandbars with greater area, higher proportions of coarse grain sand and faster bottom current velocity, while the eastern sand darter used a wider range of sandbar habitats. The landscape scale analysis revealed that contributing drainage area was an important predictor for both species, while sinuosity, which presumably represents valley type also contributed to the western sand darter’s habitat suitability. Sandbar quality (area, grain size, and velocity) and fluvial geomorphic variables (drainage area and valley type) are likely key driving factors structuring sand darter distributions in the Elk River. This multiscale study of within-river species distribution and habitat use is unique, given that only a few sympatric populations are known of western and eastern sand darters

Considering Overhead Costs in Road and Landing Spacing Models

Existing road and landing spacing models assume that spacing affects only the costs of road construction and skidding. However, costs that are independent of production and fixed on the basis of time will vary with spacing when specified on a "per-unit-volume produced" basis and therefore should be considered in the model. Costs of this nature are labeled overhead, and considering these costs in the model will lower total costs. The relationship of overhead costs to spacing follows the same pattern as the skidding costs and can be added to the cost of owning and operating the skidder in the model. Overhead costs were considered in models pertaining to three unique sets of conditions: skidding to roadside with a single road standard; skidding to roadside with two road standards; and skidding to a landing. In all cases, considering overhead in the model lowered total cost and reduced road spacing. Actual cost savings will depend on harvest conditions but can be significant

Lectin based glycoprotein analysis

Many of the biopharmaceutical therapeutics entering the market and currently in clinical trails are recombinant glycoprotein molecules, the glycan moieties of which have a significant impact on efficacy and immunogenicity. The cell culture techniques required to produce these glycoproteins often result in products that are heterogeneous with respect to glycan content. This inconsistency ultimately leads to increased production costs and restricts patient accessibility to these therapeutics. To overcome these difficulties novel analytical platforms facilitating rapid in-process monitoring and product quality control are essential. Work undertaken within the Centre for Bioanalytical Sciences (CBAS) seeks to exploit the microbial world as a source of novel biorecognition elements to produce such platforms

Production of lectin-affinity matrices for process-scale glycoprotein purification

A selection of prokaryotic lectins with a variety of glycan specificities and affinities have been identified, cloned, expressed in Eschericia coli and characterised. The aims of this project are to: - express the lectins at 1L scale to produce sufficient quantities for immobilisation studies (~100 mg) - immobilisethelectinsonSepharose - evaluate lectin performance on column by monitoring their ability toreproducibly capture and elute glycoprotein glycoforms

Exploiting prokaryotic chitin-binding proteins for glycan recognition

• The cloning, expression and characterisation of prokaryotic chitin-binding proteins from Serratia marcescens, Pseudomonas aeruginosa, Photorhabdus luminescens Microfluidics and Photorhabdus asymbiotica • Development of an assay to assess the activity of chitin-binding proteins • Mutagenesis of chitin-binding proteins to alter glycan recognition pattern

"Precious Metals-Exchange Rate Volatility Transmissions and Hedging Strategies"

This study examines the conditional volatility and correlation dependency and interdependency for the four major precious metals (that is, gold, silver, platinum and palladium), while accounting for geopolitics within a multivariate system. The implications of the estimated results for portfolio designs and hedging strategies are also analyzed. The results for the four metals system show significant short-run and long-run dependencies and interdependencies to news and past volatility. These results have become more pervasive when the exchange rate and FFR are included. Monetary policy also has a differential impact on the precious metals and the exchange rate volatilities. Finally, the applications of the results show the optimal weights in a two-asset portfolio and the hedging ratios for long positions.