Alexander G. de G. Matthews

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Gaussian process classification is a popular method with a number of appealing properties. We show how to scale the model within a variational inducing point framework, out-performing the state of the art on benchmark datasets. Importantly, the variational formulation can be exploited to allow classification in problems with millions of data points, as we(More)
Gaussian process (GP) models form a core part of probabilistic machine learning. Considerable research effort has been made into attacking three issues with GP models: how to compute efficiently when the number of data is large; how to approximate the posterior when the likelihood is not Gaussian and how to estimate covariance function parameter posteriors.(More)
Mercury and methyl mercury concentrations were determined in the muscle of 12 of the most important commercial fish species found in Seychelles waters. The concentration of mercury in a few of the larger specimens of Kingfish (Acanthocybium solandri), Becune (Sphyraena forsteri), Carangue balo (Caranx gymnostethus), and Bonito (Euthynnus affinis) exceeded(More)
[1] Measurements have been made of the effect of compaction on water retention, saturated hydraulic conductivity, and porosity of two English soils: North Wyke (NW) grassland clay topsoil and Broadbalk silty topsoil, fertilized inorganically (PKMg) or with farmyard manure (FYM). As expected, the FYM topsoil had greater porosity and greater water retention(More)
In ruminants, pancreatic alpha-amylase is the primary enzyme responsible for the initial hydrolysis of alpha-linked glucose in the small intestinal lumen. The objective of this experiment was to examine the effects of altered dietary starch and energy supply on the expression of pancreatic alpha-amylase mRNA, protein and activity in lambs. Wether lambs (n =(More)
Glutamate metabolism is essential to support many facets of metabolism. The objective of this study was to determine the tissue distribution of glutamate transporters known to support the tissue metabolism of glutamate. The expression of proteins capable of high-affinity glutamate transport (system X-(AG)) by epithelia isolated from the rumen, omasum,(More)
The variational framework for learning inducing variables (Titsias, 2009a) has had a large impact on the Gaussian process literature. The framework may be interpreted as minimizing a rigorously defined Kullback-Leibler divergence between the approximating and posterior processes. To our knowledge this connection has thus far gone unre-marked in the(More)
Glutamate is a central metabolite for whole-animal energy and N metabolism. This study tested the hypothesis that ileal epithelium, liver, and kidney content of system X-(AG) glutamate transporters EAAC1 and GLT-1 would be up-regulated to support growth of wethers (30 +/- 1.2 kg) fed a forage-based diet for at least 14 d to gain (2.0 x NEm; n = 9) vs.(More)
1. The main carotenoids in wild Penaeus monodon exoskeleton were astaxanthin di- and mono-esters, astaxanthin, and beta-carotene. 2. Wild P. monodon exoskeleton contained on average 26.3 ppm total carotenoid; normally pigmented farmed shrimp had a similar concentration (25.3 ppm). 3. Exoskeletons of farmed "blue" P. monodon (i.e. blue-coloured, as opposed(More)