Charlie Laughton (School of Pharmacy) presented at our May meeting. He discussed Molecular Dynamics simulations, with the title:
`How long is a piece of string?'
`How long is a piece of string?'
Monday, 23 June 2014
April Meeting
Kim Kenobi presented at our April group meeting.
Wheat roots - shape and nutrient uptake efficiency
Kim Kenobi
As part of the ERC FutureRoots project, a large CT scanning facility, the Hounsfield Facility, has been built on the Sutton Bonington campus to look at root system architecture of wheat plants in the context of nitrogen and water uptake efficiency. The 3D CT scans will be starting to become available in the next month or so. In this talk, I will present a statistical analysis of a preliminary 2D wheat root data set. The wheat plants in the data set come from 9 lines, all of which have been assessed for nitrogen uptake efficiency in independent field trials. The wheat plants have been grown under low and high nitrate conditions and the roots have been imaged. A piece of software called RootNav has been used to extract various quantitative measurements from the root systems, including total length of root, area of convex hull, maximum width and depth, and numbers of primary and lateral roots. In addition to these traits the software returns the coordinates of points on spline curves fitted to both the primary and lateral roots. I have used the information from these spline curves to define a distance measure between two roots and used multidimensional scaling to obtain shape variables. In the talk I show how linear discriminant analysis reveals that there are substantive differences in the root system architecture of low and high nitrogen uptake efficiency wheat plants, and less emphatically between the different nitrate growth conditions. Also, the shape variables derived from the spline coordinates emerge as playing an important role in discriminating between the groups. This evidence is encouraging in the light of the aims of the FutureRoots project to identify 3D root system architectural traits that correspond to improved nutrient uptake efficiency.
Wheat roots - shape and nutrient uptake efficiency
Kim Kenobi
As part of the ERC FutureRoots project, a large CT scanning facility, the Hounsfield Facility, has been built on the Sutton Bonington campus to look at root system architecture of wheat plants in the context of nitrogen and water uptake efficiency. The 3D CT scans will be starting to become available in the next month or so. In this talk, I will present a statistical analysis of a preliminary 2D wheat root data set. The wheat plants in the data set come from 9 lines, all of which have been assessed for nitrogen uptake efficiency in independent field trials. The wheat plants have been grown under low and high nitrate conditions and the roots have been imaged. A piece of software called RootNav has been used to extract various quantitative measurements from the root systems, including total length of root, area of convex hull, maximum width and depth, and numbers of primary and lateral roots. In addition to these traits the software returns the coordinates of points on spline curves fitted to both the primary and lateral roots. I have used the information from these spline curves to define a distance measure between two roots and used multidimensional scaling to obtain shape variables. In the talk I show how linear discriminant analysis reveals that there are substantive differences in the root system architecture of low and high nitrogen uptake efficiency wheat plants, and less emphatically between the different nitrate growth conditions. Also, the shape variables derived from the spline coordinates emerge as playing an important role in discriminating between the groups. This evidence is encouraging in the light of the aims of the FutureRoots project to identify 3D root system architectural traits that correspond to improved nutrient uptake efficiency.
March Meeting
Karthik Bharath (Ohio State University) gave a talk on `Inference for large trees' on March 26, 2014.
[OSU Statistics]
[OSU Statistics]
Saturday, 1 March 2014
February Meeting: Andy Wood's talk
Andy gave us a talk on Wednesday February 26 based on his
presentation at the Leeds LASR workshop last year
Fisher-Bingham and Kent distributions on Stiefel Manifolds: see
http://www1.maths.leeds.ac.uk/statistics/workshop/lasr2013/
presentation at the Leeds LASR workshop last year
Fisher-Bingham and Kent distributions on Stiefel Manifolds: see
http://www1.maths.leeds.ac.uk/statistics/workshop/lasr2013/
Wednesday, 26 February 2014
Tuesday, 18 February 2014
Visit from Stephan Huckemann
Last month we we were very pleased to host Stephan Huckemann for the week January 19-24 who gave us an excellent talk on circular scale space methods for mode estimation with applications to stem cells.
Tuesday, 10 December 2013
Welcome!
This blog is about the EPSRC funded project on the Statistical Analysis of Manifold-Valued Data.
The project is being carried out by the Shape and Object Data Analysis (SODA) group at the University of Nottingham.
Our aim is to develop new regression models where the response (Y) and covariates (X values) lie on non-linear manifolds.
The PI of the project is Andy Wood, with Co-I's Ian Dryden, Huiling Le and Simon Preston.
The postdocs on the project are Kwang-Rae Kim and Michail Tsagris. Michail and Ray gave talks at our first group meeting on Compositional Data Analysis and Torsion Estimation respectively.
We'll let you know about progress on our project on these pages!
Our second group meeting will be held tomorrow when Ian will talk about carotid artery shape analysis and Professor Kewei Zhang will speak to us about his work in applications of Analysis to images.
The project is being carried out by the Shape and Object Data Analysis (SODA) group at the University of Nottingham.
 |
| Torsion differences in carotid arteries |
Our aim is to develop new regression models where the response (Y) and covariates (X values) lie on non-linear manifolds.
The PI of the project is Andy Wood, with Co-I's Ian Dryden, Huiling Le and Simon Preston.
The postdocs on the project are Kwang-Rae Kim and Michail Tsagris. Michail and Ray gave talks at our first group meeting on Compositional Data Analysis and Torsion Estimation respectively.
We'll let you know about progress on our project on these pages!
Our second group meeting will be held tomorrow when Ian will talk about carotid artery shape analysis and Professor Kewei Zhang will speak to us about his work in applications of Analysis to images.
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