## Archive of Previous Seminars

### 2015–2016

- Modelling Volunteer Behaviour in Large-Scale Online Crowd-Sourcing Projects
- Thursday 25th February 2016
- Robert Whittaker (UEA Mathematics)
- Various online projects (e.g. Wikipedia, OpenStreetMap and DMOZ) solicit many small individual information contributions from large numbers of volunteers. I will discuss some ideas for modelling these contributions and how they are distributed by in time and amongst the population of contributors.
- Graph Grief and other Discrete Discombobulations
- Thursday 11th February 2016
- Robert Penfold (Institute of Food Research)
I would like to consider two quite distinct problems:

- Imagine simulating the dynamics of a more-or-less complicated molecule: a system of topologically connected particles. How many interactions are possible and which particles are involved in each? (Penfold & Wilde; 2015)
- What is a "discriminant variety"? Can the answer be exploited to analyse explicit equations (arising in fluid mechanics, say) involving many parameters, where at least some appear algebraically? (Liang & Zhang; 1999)

### 2013–2014

- The Mathematics of Competition in Food Webs
- Wednesday 5th March, 4pm
- Axel G. Rossberg (Cefas)
When done properly, theoretical ecology gives rise to many interesting mathematical problems. I will discuss two examples, both of which relate to competition. The first is that of properly defining a resource competition matrix and then of computing it. This is simple if the set of consumer species competing with each other is distinct from the set of resource species they compete for, but non-trivial in natural food webs, which, in principle, have arbitrary topology. My definition leads to a matrix equation related to the non-symmetric Algebraic Riccati Equation, which I cannot solve even numerically in all cases of interest (help!). The second problem concerns the spectra of random competition matrices. Under what conditions on food-web topology will these matrices be ill conditioned, and so the resulting communities structurally unstable? Numerics suggest these conditions determine the distribution of species over trophic levels, but an analytic theory describing the phenomenon is missing (help!).

- Developments in Wave Energy Devices
- Wednesday 20th November, 4pm, S1.20
- Dr Lawrence Coates (UEA Engineering)
A brief history of wave energy devices leading to a short review of those currently being tested will lead into a discussion of the physical constraints that make such devices difficult to develop. The audience will be invited to follow the logic of the constraints to suggest possible new devices. This will be followed by a description of a possible device that needs critical analysis and testing to see if it is viable.

### 2012–2013

- Modelling bacterial growth at population and single cell levels
- Wednesday 1st May
- József Baranyi (Insitute of Food Research)
The growth of an isogenic bacterial population in a constant environment is traditionally divided into lag, exponential and stationary phases represented by a sigmoid curve on the 'Log cell conc. v. time' scale. If the natural logarithm is used, then the maximum slope of the ‘Ln counts v. time’ curve is called the specific growth rate. It can be interpreted as the increase of the population in a unit time per the number of cells producing that increase. We point out that classical autonomous sigmoid functions (Logistic, Gompertz etc) are not suitable to model these growth curves, primarily because of the rigid and scale-dependent definition of the lag phase. We introduce a non-autonomous model that is also able to accommodate the observation that the history of the cells affects their lag phase. The resultant class of differential equations was then considered as the expected value of a stochastic birth process and the relationship between the stochastic and the deterministic models will be also discussed in this talk. Conclusions will be drawn regarding the link between the lag time of single cells and that of the population.

- Can We Model Small Bowel Peristalsis?
- Wednesday 20th March
- Prof Glyn Johnson (Norwich Medical School)
Contractions of the small and large intestine are responsible for mixing ingested food with digestive secretions, facilitating contact between intestinal contents and intestinal mucosa to allow optimal absorption of nutrients, water and electrolytes and net propulsion of contents through the gut. Proper function is essential for good nutrition and, possibly more interestingly, for effective absorption of oral medication. However, methods for assessing motility are either crude and non-quantitative (auscultation, barium x-rays) or difficult and invasive (pressure measurement). Recently Andoni Toms used rapid MRI scanning at NNUH to monitor gut motility. However, limited coverage and temporal resolution, and the complexity of gut motility limit analysis to global measurements of overall signal change which are difficult to interpret. Can modelling gut motility help interpretation of these data and, ultimately, be used to predict transport of drugs into the blood stream?

- Logic as a Modelling Tool
- Wednesday 27th February, 4pm S1.20
- Prof Mirna Džamonja (UEA School of Mathematics)
Logic was invented as a science exploring the human thought and has since been used as a tool to model the way we think and behave in various contexts. This includes mathematics, computer sciences, decision making and the theory of knowledge. We shall discuss some of these contexts and finish by describing a modelling situation in social sciences on which we have started to work.

### 2011–2012

- Drug Delivery to the Eye
- Wednesday 16th November, 4pm, SCI 3.05
- Dr Susan Barker (UEA School of Pharmacy)
Conventional eye drops are not ideal as the blink reflex means that a lot of the applied drop is blinked away. This, coupled with tear fluid movement, means that the ocular bioavailability is extremely low. We have been working with a company looking at an alternative approach, i.e. spraying a fine mist of droplets onto the surface of the eye, so as not to trigger the blink reflex and hopefully improve retention on the ocular surface.

We have looked at the potential surface damage caused to the eye by this approach, using pig eyes from the abattoir, and spraying different volumes at different rates from different heights, taking high speed video images. From the videos, it is apparent that the spray is not necessarily homogeneous and that there is some rebound splashing from the surface of the eye. Mathematically, what would be interesting is to look at the flow patterns and assess whether there is an optimum flow pattern to maximise surface coverage and minimise surface damage.

- Emergency Landing of Aircraft on Water (FP7 project SMAES)
- Wednesday 12th October, 4pm, SCI 1.20
- A. Iafrati (INSEAN — The Italian Ship Model Basin) & Alan Tassin (UEA School of Mathematics)
Ditching analysis is requested for large transport aircraft by EASA. The respective requirements are primarily devoted to a minimisation of risks for immediate injuries and the provision of fair chances for an evacuation. A significant part of average air travel is over water and historically a planned or unplanned water-landing event occurs grossly speaking every 5 years. The primary outcome of the SMAES project will be advanced methodologies and simulation tools to support aircraft development from pre-project phase to certification.

These will enhance future innovation in aircraft design through ensuring that innovative designs are compliant with safety requirements. The key developments addressed in the work programme are:

- Improved models for the calculation of ditching loads including both analytical and detailed fluid dynamics models. Inclusion of the effects of the complex flow physics in ditching is critical to prediction of ditching loads.
- Reliable and predictive aircraft models for structural behaviour under dynamic fluid loads.
- Demonstration of the methods on representative future aircraft design concepts.

The consortium brings together aircraft manufacturers, analysis software developers, research organisations and universities. INSEAN is involved in the development of a testing facility at high horizontal speed which will make it possible to test fuselage panels under hydrodynamic loads. UEA is involved in the development of a semi-analytical tool for the calculation of hydrodynamic loads during ditching taking into account structure deformations and complex flow phenomena (suction forces, ventilation, cavitation).

- Study Group Preview
- Friday 13th April, 2:30pm, S1.20
- This will provide an opportunity for UEA people to have an initial think about some of the study group problems that will be presented at the upcoming ESGI 85.

### 2010–2011

- TinyLVR and Uncertainties in Regression Coefficients
- Wednesday 23rd March, 4pm, SCI 3.05
- Dr Henri Tapp (Institute of Food Research)
- I shall describe TinyLVR, which is a method of representing any multivariate model for a single dependant variable in terms of a two-factor latent vector model. This allows it to be viewed using 2-D plots. The remainder of the talk will consider the calculation of realistic estimates of the uncertainties in regression coefficients derived from a latent vector method, and the associated significance levels of the coefficients.
- Getting the Perfect Cleavage — Subcellular Filaments and Developmental Processes
- Wednesday 30th March, 4pm, SCI 3.05
- Dr Scott Grandison (UEA School of Computing Sciences)
- Microtubules are subcellular filaments that are associated with many functions including cell division, nuclear positioning and growth. They interact with each other in simple ways, yet from those simple interactions they are able to form complex structures. It's this combination of complex behaviour arising from simple interactions that makes them an attractive system for theoretical study. In this talk I'll present some of our recent modelling work and speculate how further progress might be made by leveraging some mathematics instrumental to the design of model televisions.
- Modelling Symbiotic Calcium Oscillations
- Wednesday 11th May, 4pm, SCI 3.05
- Dr Richard Morris (John Innes Centre)
*Biological Background*: Plant growth is frequently limited by the essential nutrients nitrogen and phosphorus. Several plant species have established symbiotic relationships with microorganisms to overcome such limitations. In addition to the symbiotic relationship with arbuscular mycorrhizal fungi that many plants enter into to secure their phosphorus uptake, legumes establish interactions with rhizobial bacteria that results in fixed atmospheric nitrogen being transferred to the plant. These very different developmental programmes that legumes undergo employ the same signaling pathway with many components being common to both symbioses. In particular, both the mychorrizal and rhizobial interactions share characteristic perinuclear calcium oscillations that are thought to be a potential source of specificity for downstream events. It is thus important to understand the generation of the calcium oscillations, their specificity and how they are robustly decoded.*Methods*: I will present our work on the non-linear time series analysis of symbiotic calcium oscillations and introduce Bayesian techniques we developed for extracting frequencies. I will introduce methods we explored for automatically deriving models from time course data and discuss their pros and cons. Finally, I will present our current model of calcium oscillations that is able to reproduce a number of experimental observations and make some key predictions regarding the nature of the unknown molecular components. I will end with an outlook of the spatial work we are currently undertaking and how this may couple to decoding mechanisms.- Dissecting a Subcellular Concentration Gradient in Fission Yeast
- Wednesday 25th May, 3pm, SCI 3.05
- Prof Martin Howard (John Innes Centre)
- The topic concerns a chemical gradient inside a single yeast cell that regulates cell division positioning, cell polarity, and cell length. We recently discovered that the intrinsic dynamics of the gradient were substantially more complex than previously realised. In particular the protein that makes the gradient appears to form transient clusters. We modelled this mathematically using a simplified set of reaction-diffusion equations, but a more precise description would be desirable, involving a more sophisticated aggregation-fragmentation model.

### 2009–2010

- Microscale DNA tightropes created using fluid flow as a platform for direct imaging of enzyme search mechanisms during DNA repair
- 2009-12-02
- Dr Neil Kad (Biological Sciences, University of Essex)
- Stochastic Resonance in Extended Systems: The Nonequilibrium Potential Approach
- 2009-11-11
- Prof Horacio S. Wio (Instituto de Física de Cantabria, Universidad de Cantabria & CSIC, Spain)
- A numerical method for three-dimensional water impact problems based on the Wagner theory and the boundary element method
- 2009-10-14
- Alan Tassin (ENSIETA, Brest, France and DCNS Group)

### 2008–2009

- Prediction of Spectroscopic properties of complex molecular systems prior to actual Experiment
- 2008-12-03
- Vasily Oganesyan (CAP)
- A Turing-like mechanism for the initation of root-hair growth
- 2008-11-17
- Alan Champneys (Bristol)
- Global seismic imaging: probing the Earth's deep interior using seismic waves
- 2008-11-12
- Ana Ferreira (ENV)
- Interdisciplinary research: Our answer to the Marine Industry
- 2008-10-08
- Hannes Bogaert (MARIN - MAritime Research Institute Netherlands)

### 2007–2008

- Freak Waves: Facts and Theories
- 28.05.2008
- Efim Pelinovsky (Leverhulme Professor, Loughborough University)
- Non-linear free-surface flows in ship hydrodynamics
- 14.05.2008
- Alessandro Iafrati (INSEAN, Italian Ship Model Basin)
- Do Somos Sequences appear in nature?
- 05.03.2008
- Prof Graham Everest (MTH)
- Mathematics of Mass Spectrometry
- 30.01.2008
- Dr Andrew Watson (IFR)
- It's tough at the tip: Modelling polar growth
- 12.12.2007
- Dr Scott Grandison (JIC)
- A gravity instrument mounting problem
- 10.10.2007
- Dominic Hopkins (Bell Geospace/ formerly UEA MTH student)

### 2006–2007

- Three problems: asymmetries in shaped charges, oil well perforation and minimisation of heat loss.
- 23.05.2007
- Dr John Curtis (QinetiQ)
- Phut. Whee. Splat. The life of an inkjet drop.
- 28.02.2007
- Dr Andrew Clarke (Kodak)
- Cox regression and geographically weighted regression
- 24.01.2007
- Alejandro de las Heras (ENV)
- Models of the digestive process
- 17.01.2007
- Dr Martin Wickham (IFR)
- The effects of climate change on one species of grasshopper in temperate, heterogenous habitats
- 29.11.2006
- Tom Waite (ENV)
- Modelling interaction between ice shelves and oceans
- 15.11.2006
- Dr Paul Holland (British Antarctic Survey
- Dispersal, Sources and Sinks in cooperation and conservation
- 13.11.2006
- Dr Douglas Yu (BIO)
- Mystery Talk
- 11.10.2006
- Paul Archer-Simms (Aquabarrier Ltd.)

### 2005–2006

- Transcriptome-based prediction of hybrid vigour and other complex traits in Arabidopsis
- 07.06.2006
- Dr Ian Bancroft (JIC)
- Deterministic and stochastic models of bacterial growth - from population to single cell level kinetics
- 22.03.2006
- Dr József Baranyi (IFR)
- Effectiveness and cost effectiveness of early and late prevention of HIV/AIDS progression with antiretrovirals or antibiotics in southern African adults
- 15.02.2006
- Prof Max Bachmann (MED)
- Attractors of a dynamical system corresponding to a minimization problem
- 08.02.2006
- Zoltan Kutalik (CMP)
- Predicting the probability of parasitaemic peaks and perturbations.
- 06.02.2006
- Dr Kevin Tyler (MED)
- Mathematical techniques for predicting protein function from structure
- 07.12.2005
- Dr Richard Morris (JIC)
- The Origins of Tsunamis
- 30.11.2005
- Dr Donard de Cogan (CMP)

### 2004–2005

- Some novel concepts in heat-flow modelling
- 20.04.2005
- Dr Donard de Cogan (CMP)
- Three dimensional imaging using photo thermal spectroscopy
- 09.03.2005
- Prof Mike Reading (CAP)
- Mathematical modelling of bird feeding behaviour
- 29.09.2004
- Dr Paul Hammerton and Dr Mark Blyth (MTH)
- Unsteady selective withdrawal - recent advances
- 29.09.2004
- Dr Graeme Hocking (Math and Statistics, Murdoch University)

### 2003–2004

- Chocolate: An inverse problem?
- 10.12.2003
- Dr Robert Penfold (IFR)
- Volcanic activity triggered by intense rainfall
- 03.12.2003
- Dr Adrian Matthews (MTH/ENV)

### 2002–2003

- A one dimensional model for ultrasound propagation in dense colloidal materials
- 20.08.2003
- Dr Paul Hammerton (MTH)
- Ultrasound propagation in dense colloidal materials.
- 24.06.2003
- CIMR Workshop.
- Inflation of a pressure-limited cuff inside a model trachea
- 19.02.2003
- Dr P. Young (Consultant anaesthetist, King's Lynn) and Prof W. H. Young (formerly of UEA physics)
- A stochastic model of gene order evolution
- 27.11.2002
- George Savva (JIC)
- A review of ultrasound interaction with colloidal dispersive media
- 20.11.2002
- Dr Mark Cooker (MTH)
- The effect of vorticity on nonlinear free-surface flows
- 06.11.2002
- Prof Jean-Marc Vanden-Broeck (MTH)
- Electrostatic models of protein aggregation
- 16.10.2002
- Dr Scott Grandison (MTH)

### 2001–2002

- Phase behaviour of a quasi one-dimensional model lipid monolayer
- 30.01.2002
- Dr Moises Silbert (CHE)
- Aerodynamics of sport
- 05.12.2001
- Dr Paul Hammerton (MTH)
- Numerical modelling of the Doppler effect
- 07.11.2001
- Dr Donard de Cogan (CMP)
- Reaction-diffusion equations in chemical systems
- 04.10.2001
- Dr Nigel Scott (MTH)

### 2000–2001

- Granular flows
- 27.06.2001
- Gary Barker (IFR)
- Measuring the origin and authenticity of food
- 20.06.2001
- Peter Belton (IFR)
- Cryptography and integer sequences
- 13.06.2001
- Graham Everest (MTH)
- Categorical time series
- 30.05.2001
- Gareth Janacek (MTH)
- Graphs and images: from photos to art
- 25.04.2001
- Richard Harvey (SYS)
- Some mathematics for violent pipe flows
- 21.03.2001
- Mark Cooker (MTH)
- Applications of the contraction mapping principle
- 28.02.2001
- Danilo Mandic (SYS)
- Does sampling a complex process mean anything?
- 14.02.2001
- Tom Ward (MTH)
- Eat drink and be numerate
- 31.01.2001
- Afternoon of talks at IFR
- Some amenable problems in biosensor protein engineering and food structure/rheology relationships
- 15.11.2000
- Rob Penfold (IFR)
- Introduction to CIMR and free-surface flows with surface tension
- 01.11.2000
- J-M. Vanden-Broeck (MTH)