Past Industrial and Interdisciplinary Workshops

26 February 2010
10:00
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11:15
Jorn Dunkel
Abstract
Micron-sized bacteria or algae operate at very small Reynolds numbers. In this regime, inertial effects are negligible and, hence, efficient swimming strategies have to be different from those employed by fish or bigger animals. Mathematically, this means that, in order to achieve locomotion, the swimming stroke of a microorganism must break the time-reversal symmetry of the Stokes equations. Large ensembles of bacteria or algae can exhibit rich collective dynamics (e.g., complex turbulent patterns, such as vortices or spirals), resulting from a combination of physical and chemical interactions. The spatial extent of these structures typically exceeds the size of a single organism by several orders of magnitude. One of our current projects in the Soft and Biological Matter Group aims at understanding how the collective macroscopic behavior of swimming microorganisms is related to their microscopic properties. I am going to outline theoretical and computational approaches, and would like to discuss technical challenges that arise when one tries to derive continuum equations for these systems from microscopic or mesoscopic models.
  • Industrial and Interdisciplinary Workshops
19 February 2010
10:00
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11:15
Abstract
I have reconstructed multiple palaeoecological records from sites across the British Isles; this work has resulted in detailed time series that demonstrate changes in vegetation, herbivore density, nitrogen cycling, fire levels and air temperature across an 8,000 year time span covering the end of the last glacial period. The aim of my research is to use statistics to infer the relationships between vegetation changes and changes in the abiotic and biotic environment in which they occurred. This aim is achieved by using a model-fitting and model-selection method whereby sets of ordinary differential equations (ODE) are ‘fitted’ to the time series data via maximum likelihood estimation in order to find the model(s) that provide the closest match to the data. Many of the differential equation models that I have used in this study are well established in the theoretical ecology literature (i.e. plant – resource dynamics and plant – herbivore dynamics); however, there are no existing ODE models of fire or temperature dynamics that were appropriate for my data. For this workshop, I will present the palaeoecological data that I collected along with the models that I have chosen to work with (including my first attempt at models for fire and temperature dynamics) and I hope to get your feedback on these models and suggestions for other useful modelling methods that could be used to represent these dynamics.
  • Industrial and Interdisciplinary Workshops
12 February 2010
10:00
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11:15
Abstract
The significance of the effects of non-healing wounds has been the topic of many research papers and lectures during the last 25 years. Efforts have been made to understand the effects of long-standing venous hypertension, diabetes, the prevalence of wounds in such conditions with as well as the difficulties faced in managing such wounds with some success. Successful efforts to define standard care regimes have also been made. However, attempts to introduce innovative therapy have been much less successful. Is this merely because we have not understood the intricacies of the problem? And would system based modelling be an untried technique? Venous ulcers are the majority of lower extremity wounds, and a clinical challenge. A previously developed model of venous ulcers permits some understanding of why compression bandaging is successful but fails to accommodate complications such as exudate and infection. Could this experimental model be improved by system based modelling? Chronic wounds need to be modelled however the needs for such models should be examined in order that the outcome permits advances in our thinking as well in clinical management.
  • Industrial and Interdisciplinary Workshops
5 February 2010
10:00
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11:15
Trevor Wishart
Abstract
Trevor Wishart writes "I realise 'irrational' means something very specific to a mathematician, and I'm not using the word in that sense." Abstract: Trevor Wishart will discuss the use of Digital Signal Processing as a tool in musical composition, ranging from the application of standard analysis procedures (e.g. windowed Fourier Transforms), and common time-domain methods (Brassage), to more unconventional approaches (e.g. waveset distortion, spectral tracing, iterative-extension). He will discuss the algorithms involved and illustrate his talk with musical examples taken from his own work. This workshop is linked to a musical performance of "Two Women" and "Globalalia" by Trevor Wishart in the Jacqueline du Pre concert hall that evening (5th Feb) at 8pm as part of the Music Department's "New Music Forum". Tickets are £12 (or £8 concession) but if you are interested please let me know (Rebecca Gower, gower@maths.ox.ac.uk or 152312) as we may be able to negotiate a much lower price for members of the Mathematical Institute in a group associated with his workshop. Trevor will also be giving two lectures in the Denis Arnold Hall, Faculty of Music on the 3rd and 4th Feb which are open to the public and admission is free.
  • Industrial and Interdisciplinary Workshops
29 January 2010
10:00
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11:15
Abstract
When the human eye looks at a distant object, the lens is held in a state of tension by a set of fibres (known as zonules) that connect the lens to the ciliary body. To view a nearby object, the ciliary muscle (which is part of the ciliary body) contracts. This reduces the tension in the zonules, the lens assumes a thicker and more rounded shape and the optical power of the eye increases. This process is known as accommodation. With increased age, however, the accommodation mechanism becomes increasingly ineffective so that, from an age of about 50 years onwards, it effectively ceases to function. This condition is known as presbyopia. There is considerable interest in the ophthalmic community on developing a better understanding of the ageing processes that cause presbyopia. As well as being an interesting scientific question in its own right, it is hoped that this improved understanding will lead to improved surgical procedures (e.g. to re-start the accommodation process in elderly cataract patients).
  • Industrial and Interdisciplinary Workshops

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