BAYESIAN MCMC ANALYSES FOR REGULATORY ASSESSMENTS OF FOOD COMPOSITION

In order to gain regulatory approval to market a new seed product derived with biotechnology, grain and forage composition data must be collected from field trials, and summaries must be reported to various government agencies. Currently, both tests of differences in composition between a genetically modified organism (GMO) and its control and tests of equivalence of the GMO to conventional genotypes are required by regulatory agencies. Bayesian analyses offer an attractive option for regulatory assessments by expressing results that can be interpreted more easily by a wide audience and by providing more ways to examine various hypotheses of interest. In order to extend Bayesian methodology for application to different compositional analytes, and to take advantage of the information obtained in previous experiments, the use of informative prior distributions for composition studies is proposed. Methods for determining suitable informative prior distributions analytically are shown in four situations: (1) eliciting opinions from an expert, (2) finding the best fit from an overdetermined set of summary statistics from one previous study, (3) performing a meta-analysis of summary statistics from previous studies with an assumed common prior distribution, and (4) performing a different meta-analysis with the prior distribution determined by a mixture of different assumed prior distributions from previous studies. Examples from soybean composition studies are used to illustrate these techniques

Report on the State of Available Data for the Study of International Trade and Foreign Direct Investment

This report, prepared for the Committee on Economic Statistics of the American Economic Association, examines the state of available data for the study of international trade and foreign direct investment. Data on values of imports and exports of goods are of high quality and coverage, but price data suffer from insufficient detail. It would be desirable to have more data measuring value-added in trade as well as prices of comparable domestic and imported inputs. Value data for imports and exports of services are too aggregated and valuations are questionable, while price data for service exports and imports are almost non-existent. Foreign direct investment data are of high quality but quality has suffered from budget cuts. Data on trade in intellectual property are fragmentary. The intangibility of the trade makes measurement difficult, but budget cuts have added to the difficulties. Modest funding increases would result in data more useful for research and policy analysis.

Future hot-spots for hydro-hazards in Great Britain: a probabilistic assessment

In an increasing hydro-climatic risk context as a result of climate change, this work aims to identify future hydro-hazard hot-spots as a result of climate change across Great Britain. First, flood and drought hazards were defined and selected in a consistent and parallel approach with a threshold method. Then, a nation-wide systematic and robust statistical framework was developed to quantify changes in frequency, magnitude, and duration, and assess time of year for both droughts and floods, and the uncertainty associated with climate model projections. This approach was applied to a spatially coherent statistical database of daily river flows (Future Flows Hydrology) across Great Britain to assess changes between the baseline (1961–1990) and the 2080s (2069–2098). The results showed that hydro-hazard hot-spots are likely to develop along the western coast of England and Wales and across north-eastern Scotland, mainly during the winter (floods) and autumn (droughts) seasons, with a higher increase in drought hazard in terms of magnitude and duration. These results suggest a need for adapting water management policies in light of climate change impact, not only on the magnitude, but also on the timing of hydro-hazard events, and future policy should account for both extremes together, alongside their potential future evolution.</p

“Dynamic Range” of Inferred Phenotypic HIV Drug Resistance Values in Clinical Practice

Background: ‘Virtual ’ or inferred phenotypes (vPhenotypes) are commonly used to assess resistance to antiretroviral agents in patients failing therapy. In this study, we provide a clinical context for understanding vPhenotype values. Methods: All HIV-infected persons enrolled in the British Columbia Drug Treatment Program with a baseline plasma viral load (pVL) and follow-up genotypic resistance and pVL results were included up to October 29, 2008 (N = 5,277). Change from baseline pVL was determined as a function of Virco vPhenotype, and the ‘‘dynamic range’ ’ (defined here by the 10th and 90th percentiles for fold-change in IC50 amongst all patients) was estimated from the distribution of vPhenotye foldchanges across the cohort. Results: The distribution of vPhenotypes from a large cohort of HIV patients who have failed therapy are presented for all available antiretroviral agents. A maximum change in IC50 of at least 13-fold was observed for all drugs. The dideoxy drugs, tenofovir and most PIs exhibited small ‘‘dynamic ranges’ ’ with values of,4-fold change observed in.99 % of samples. In contrast, zidovudine, lamivudine, emtricitabine and the non-nucleoside reverse transcriptase inihibitors (excluding etravirine) had large dynamic ranges. Conclusion: We describe the populational distribution of vPhenotypes such that vPhenotype results can be interprete

Natural Products Chemistry and Taxonomy of the Marine Cyanobacterium Blennothrix cantharidosmum

A Papua New Guinea field collection of the marine cyanobacterium Blennothrix cantharidosmum was investigated for its cytotoxic constituents. Bioassay-guided isolation defined the cytotoxic components as the known compounds lyngbyastatins 1 and 3. However, six new acyl proline derivatives, tumonoic acids D−I, plus the known tumonoic acid A were also isolated. Their planar structures were defined from NMR and MS data, while their stereostructures followed from a series of chiral chromatographies, degradation sequences, and synthetic approaches. The new compounds were tested in an array of assays, but showed only modest antimalarial and inhibition of quorum sensing activities. Nevertheless, these are the first natural products to be reported from this genus, and this inspired a detailed morphologic and 16S rDNA-based phylogenetic analysis of the producing organism

Predicting Bone Mechanical Properties of Cancellous Bone from DXA, MRI, and Fractal Dimensional Measurements

This project was aimed at making predictions of bone mechanical properties from non-invasive DXA and MRI measurements. Given the bone mechanical properties, stress calculations can be made to compare normal bone stresses to the stresses developed in exercise countermeasures against bone loss during space flight. These calculations in turn will be used to assess whether mechanical factors can explain bone loss in space. In this study we assessed the use of T2(sup *) MRI imaging, DXA, and fractal dimensional analysis to predict strength and stiffness in cancellous bone

Longitudinal community plasma HIV-1 RNA concentrations and incidence of HIV-1 among injecting drug users: prospective cohort study

Objective To examine the relation between plasma HIV-1 RNA concentrations in the community and HIV incidence among injecting drug users

Einstein, incompleteness, and the epistemic view of quantum states

Does the quantum state represent reality or our knowledge of reality? In making this distinction precise, we are led to a novel classification of hidden variable models of quantum theory. Indeed, representatives of each class can be found among existing constructions for two-dimensional Hilbert spaces. Our approach also provides a fruitful new perspective on arguments for the nonlocality and incompleteness of quantum theory. Specifically, we show that for models wherein the quantum state has the status of something real, the failure of locality can be established through an argument considerably more straightforward than Bell's theorem. The historical significance of this result becomes evident when one recognizes that the same reasoning is present in Einstein's preferred argument for incompleteness, which dates back to 1935. This fact suggests that Einstein was seeking not just any completion of quantum theory, but one wherein quantum states are solely representative of our knowledge. Our hypothesis is supported by an analysis of Einstein's attempts to clarify his views on quantum theory and the circumstance of his otherwise puzzling abandonment of an even simpler argument for incompleteness from 1927.Comment: 18 pages, 8 figures, 1 recipe for cupcakes; comments welcom