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Operating at the extreme: Estimating the upper yield boundary of winter wheat production in commercial practice (2020)
Journal Article
Mitchell, E. G., Crout, N. M., Wilson, P., Wood, A. T., & Stupfler, G. (2020). Operating at the extreme: Estimating the upper yield boundary of winter wheat production in commercial practice. Royal Society Open Science, 7(4), https://doi.org/10.1098/rsos.191919

© 2020 The Authors. Wheat farming provides 28.5% of global cereal production. After steady growth in average crop yield from 1950 to 1990, wheat yields have generally stagnated, which prompts the question of whether further improvements are possible.... Read More about Operating at the extreme: Estimating the upper yield boundary of winter wheat production in commercial practice.

Regression modelling for size-and-shape data based on a Gaussian model for landmarks (2020)
Journal Article
Dryden, I. L., Kume, A., Paine, P. J., & Wood, A. T. A. (2021). Regression modelling for size-and-shape data based on a Gaussian model for landmarks. Journal of the American Statistical Association, 116(534), 1011-1022. https://doi.org/10.1080/01621459.2020.1724115

In this paper we propose a regression model for size-and-shape response data. So far as we are aware, few such models have been explored in the literature to date. We assume a Gaussian model for labelled landmarks; these landmarks are used to represe... Read More about Regression modelling for size-and-shape data based on a Gaussian model for landmarks.

Limiting saddlepoint relative errors in large deviation regions under purely Tauberian conditions (2019)
Journal Article
Butler, R., & Wood, A. (2019). Limiting saddlepoint relative errors in large deviation regions under purely Tauberian conditions. Bernoulli, 25(4B), 3379-3399. https://doi.org/10.3150/18-BEJ1093

Most theoretical results on the relative errors of saddlepoint approximations in the extreme tails have involved placing conditions on the density/mass function. Checking the validity of such conditions is problematic when density/mass functions are... Read More about Limiting saddlepoint relative errors in large deviation regions under purely Tauberian conditions.

Spherical regression models with general covariates and anisotropic errors (2019)
Journal Article
Paine, P. J., Preston, S. P., Tsagris, M., & Wood, A. T. A. (2020). Spherical regression models with general covariates and anisotropic errors. Statistics and Computing, 30(1), 153–165. https://doi.org/10.1007/s11222-019-09872-2

Existing parametric regression models in the literature for response data on the unit sphere assume that the covariates have particularly simple structure, for example that they are either scalar or are themselves on the unit sphere, and/or that the... Read More about Spherical regression models with general covariates and anisotropic errors.

Scaled von Mises-Fisher distributions and regression models for paleomagnetic directional data (2019)
Journal Article
Scealy, J. L., & Wood, A. T. A. (2019). Scaled von Mises-Fisher distributions and regression models for paleomagnetic directional data. Journal of the American Statistical Association, 114(528), 1547-1560. https://doi.org/10.1080/01621459.2019.1585249

We propose a new distribution for analysing paleomagnetic directional data that is a novel transformation of the von Mises-Fisher distribution. The new distribution has ellipse-like symmetry, as does the Kent distribution; however, unlike the Kent di... Read More about Scaled von Mises-Fisher distributions and regression models for paleomagnetic directional data.

Linear discriminant analysis reveals differences in root architecture in wheat seedlings related to nitrogen uptake efficiency (2017)
Journal Article
Kenobi, K., Atkinson, J. A., Wells, D. M., Gaju, O., deSilva, J. G., Foulkes, M. J., …Bennett, M. J. (2017). Linear discriminant analysis reveals differences in root architecture in wheat seedlings related to nitrogen uptake efficiency. Journal of Experimental Botany, 68(17), 4969-4981. https://doi.org/10.1093/jxb/erx300

© The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. Root architecture impacts water and nutrient uptake efficiency. Identifying exactly which root architectural properties influence these agronom... Read More about Linear discriminant analysis reveals differences in root architecture in wheat seedlings related to nitrogen uptake efficiency.

Nonparametric hypothesis testing for equality of means on the simplex (2016)
Journal Article
Tsagris, M., Preston, S. P., & Wood, A. T. (in press). Nonparametric hypothesis testing for equality of means on the simplex. Journal of Statistical Computation and Simulation, 87(2), https://doi.org/10.1080/00949655.2016.1216554

In the context of data that lie on the simplex, we investigate use of empirical and exponential empirical likelihood, and Hotelling and James statistics, to test the null hypothesis of equal population means based on two independent samples. We perfo... Read More about Nonparametric hypothesis testing for equality of means on the simplex.

Nonparametric Statistical Methods on Manifolds (2016)
Book Chapter
Dryden, I. L., Le, H., Preston, S. P., & Wood, A. T. A. (2016). Nonparametric Statistical Methods on Manifolds. In M. Denker, & E. C. Waymire (Eds.), Rabi N. Bhattacharya: Selected Papers (587-597). Springer. https://doi.org/10.1007/978-3-319-30190-7_17

One of the many fundamental contributions that Rabi Bhattacharya, together with his coauthors, has made is the development of a general nonparametric theory of statistical inference on manifolds, in particular related to both intrinsic and extrinsic... Read More about Nonparametric Statistical Methods on Manifolds.

Promotion of testa rupture during garden cress germination involves seed compartment-specific expression and activity of pectin methylesterases (2015)
Journal Article
Scheler, C., Weitbrecht, K., Pearce, S. P., Hampstead, A., Büttner-Mainik, A., Lee, K. J., …Leubner-Metzger, G. (2015). Promotion of testa rupture during garden cress germination involves seed compartment-specific expression and activity of pectin methylesterases. Plant Physiology, 167(1),

Pectin methylesterase (PME) controls the methylesterification status of pectins and thereby determines the biophysical properties of plant cell walls, which are important for tissue growth and weakening processes. We demonstrate here that tissue-spec... Read More about Promotion of testa rupture during garden cress germination involves seed compartment-specific expression and activity of pectin methylesterases.

Laplace approximation of Lauricella functions F A and F D (2014)
Journal Article
Butler, R., & Wood, A. T. (2015). Laplace approximation of Lauricella functions F A and F D. Advances in Computational Mathematics, 41(6), https://doi.org/10.1007/s10444-014-9397-5

The Lauricella functions, which are generalizations of the Gauss hypergeometric function 2 F 1, arise naturally in many areas of mathematics and statistics. So far as we are aware, there is little or nothing in the literature on how to calculate nume... Read More about Laplace approximation of Lauricella functions F A and F D.

An objective approach to model reduction: Application to the Sirius wheat model (2014)
Journal Article
Craigon, J., Cox, G., Crout, N., Jao, Y., Tarsitano, D., Wood, A., & Semenov, M. (2014). An objective approach to model reduction: Application to the Sirius wheat model. Agricultural and Forest Meteorology, 189-190(100), 211-219. https://doi.org/10.1016/j.agrformet.2014.01.010

An existing simulation model of wheat growth and development, Sirius, was evaluated through a systematic model reduction procedure. The model was automatically manipulated under software control to replace variables within the model structure with co... Read More about An objective approach to model reduction: Application to the Sirius wheat model.

Saddlepoint approximations for the normalizing constant of Fisher–Bingham distributions on products of spheres and Stiefel manifolds (2013)
Journal Article
Kume, A., Preston, S., & Wood, A. T. (2013). Saddlepoint approximations for the normalizing constant of Fisher–Bingham distributions on products of spheres and Stiefel manifolds. Biometrika, 100(4), https://doi.org/10.1093/biomet/ast021

In an earlier paper Kume & Wood (2005) showed how the normalizing constant of the Fisher– Bingham distribution on a sphere can be approximated with high accuracy using a univariate saddlepoint density approximation. In this sequel, we extend the ap... Read More about Saddlepoint approximations for the normalizing constant of Fisher–Bingham distributions on products of spheres and Stiefel manifolds.