Functional differential equations arising in cell-growth

Non-local differential equations are notoriously difficult to solve. Cell-growth models for population growth of a cohort structured by size, simultaneously growing and dividing, give rise to a class of non-local eigenvalue problems, whose “principal” eigenvalue is the time-constant for growth/decay. These and other novel non-local problems are described and solved in special cases in this paper

<i>Saccharomyces cerevisiae</i> in the production of whisk(e)y

Whisk(e)y is a major global distilled spirit beverage. Whiskies are produced from cereal starches that are saccharified, fermented and distilled prior to spirit maturation. The strain of Saccharomyces cerevisiae employed in whisky fermentations is crucially important not only in terms of ethanol yields, but also for production of minor yeast metabolites which collectively contribute to development of spirit flavour and aroma characteristics. Distillers must therefore pay very careful attention to the strain of yeast exploited to ensure consistency of fermentation performance and spirit congener profiles. In the Scotch whisky industry, initiatives to address sustainability issues facing the industry (for example, reduced energy and water usage) have resulted in a growing awareness regarding criteria for selecting new distilling yeasts with improved efficiency. For example, there is now a desire for Scotch whisky distilling yeasts to perform under more challenging conditions such as high gravity wort fermentations. This article highlights the important roles of S. cerevisiae strains in whisky production (with particular emphasis on Scotch) and describes key fermentation performance attributes sought in distiller’s yeast, such as high alcohol yields, stress tolerance and desirable congener profiles. We hope that the information herein will be useful for whisky producers and yeast suppliers in selecting new distilling strains of S. cerevisiae, and for the scientific community to stimulate further research in this area

The Unusual Spectrum of Comet 96P/Machholz

We report spectra from 3000-5900 A for comet 96P/Machholz, obtained on 2007 Apr 27 UT with the 3-m Shane telescope at Lick Observatory. The spectra are extremely carbon poor, and show a prominent NH_2 series, but no CN emission. NH, NH_2, and C_2 gas production rates are (8.36 +/- 2.18)x10^25, (29.88 +/- 3.66)x10^25, and (4.52 +/- 0.61)x10^23 molecules sec^-1, respectively, as determined from Haser model fits to the data. Upper limits to the gas production rates for CN and C_3 are 7.5x10^22 and 2.0x10^23, respectively. Though 96P is depleted in C_2 and C_3 relative to NH, it is even more depleted in CN than other so-called "carbon-chain depleted" comets.Comment: 14 pages, 4 tables, 2 figures, accepted for publication in ApJ

Linear and nonlinear aspects of the tropical 30-60 day oscillation: A modeling study

The scientific problem focused on study of the tropical 30-60 day oscillation and explanation for this phenomenon is discussed. The following subject areas are covered: the scientific problem (the importance of low frequency oscillations; suggested mechanisms for developing the tropical 30-60 day oscillation); proposed research and its objective; basic approach to research; and results (satellite data analysis and retrieval development; thermodynamic model of the oscillation; the 5-level GCM)

Non-compliance with randomised allocation and missing outcome data in randomised controlled trials evaluating surgical interventions : a systematic review

Acknowledgements JAC held MRC training (reference number: G0601938) and methodology (reference number: G1002292) fellowships while this research was undertaken. The Health Services Research Unit is core funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates. The authors accept full responsibility for this manuscript.Peer reviewedPublisher PD

PREDICTING OUTPUT FROM SEEMINGLY UNRELATED AREA AND YIELD EQUATIONS

Crop output can be defined as the product of area sown and yield. Given the existence of separate equations for explaining and predicting area sown and yield, in this paper we suggest predictors for output and derive expressions for the standard errors of the predictors. The methodology is applied to wheat production in the Corrigin Shire of Western Australia.Predicting a product, standard error of prediction, Crop Production/Industries,

The pharmacology and function of receptors for short-chain fatty acids

Despite some blockbuster G protein–coupled receptor (GPCR) drugs, only a small fraction (∼15%) of the more than 390 nonodorant GPCRs have been successfully targeted by the pharmaceutical industry. One way that this issue might be addressed is via translation of recent deorphanization programs that have opened the prospect of extending the reach of new medicine design to novel receptor types with potential therapeutic value. Prominent among these receptors are those that respond to short-chain free fatty acids of carbon chain length 2–6. These receptors, FFA2 (GPR43) and FFA3 (GPR41), are each predominantly activated by the short-chain fatty acids acetate, propionate, and butyrate, ligands that originate largely as fermentation by-products of anaerobic bacteria in the gut. However, the presence of FFA2 and FFA3 on pancreatic β-cells, FFA3 on neurons, and FFA2 on leukocytes and adipocytes means that the biologic role of these receptors likely extends beyond the widely accepted role of regulating peptide hormone release from enteroendocrine cells in the gut. Here, we review the physiologic roles of FFA2 and FFA3, the recent development and use of receptor-selective pharmacological tool compounds and genetic models available to study these receptors, and present evidence of the potential therapeutic value of targeting this emerging receptor pair