News

Congratulations to Philip Candelas on his FRS.

Further information is available on the Royal Society pages.

Observations of circular human sperm swimming and trapping in a very viscous fluid.

Mathematical modelling predictions for circular sperm swimming and trapping in a very viscous fluid.

Ever wondered how sperm know where they're going? Every one of us is the consequence of a sperm cell winning the epic race through the female tract to reach the egg, covering the equivalent distance of climbing Mount Everest. A ‘virtual sperm’ can be developed and explored, based on computational simulations of a biologically inspired mathematical model. In particular, such models highlight that changes in the surrounding fluids may cause sperm to switch from straight-swimming to going round in circles, effectively trapping them, due to a buckling-effect on the whip-like motions of the sperm tail. Characteristic features of this mechanics have also been observed in the laboratory, while understanding these mechanisms and more generally how sperm may become trapped is potentially important in developing future simple treatments and diagnoses for human subfertility and animal conservation. These results featured as a ScienceShot in Science-Now, the popular arm of the prestigious journal Science, after a recent publication in The Journal of The Royal Society Interface. The latter was authored by Hermes Gadelha and Eamonn Gaffney of The Mathematical Institute with collaborators from the Centre for Human Reproductive Science, Birmingham Women’s NHS Foundation Trust.

The university has produced a press release on Mason's Porter's work on network communities. Below is a copy of the press release:

A new way of finding community structure within networks – anything from social networks such as Facebook, to power grids, political voting networks, and protein interaction networks in biology – could help us understand how people are connected and how connections change over time. The new technique, developed by a team from the University of North Carolina, University of Oxford, and Harvard University, aims to be more realistic than conventional approaches, which only capture one type of connection or a network at only one moment in time.

The new approach captures the totality of connections within a network and could be used to examine the different ways communities form; for example, analysing relationships between University students and staff across many different connections such as Facebook friendship, College affiliation, and subject studied. Alternatively, it could be used to track how one type of connection – such as Facebook friendship – changes over time.

The technique is not limited to social networks as community detection has the potential to find important groups in many other applications, such as protein-protein interaction networks, transportation networks, and political voting networks.

A report of the team’s work, advancing the theory of community detection, will be published in this week’s Science.

‘Capturing the complexity of people's relationships through networks such as Facebook and how these relationships change over time is a huge challenge,’ said Dr Mason Porter of Oxford University's Mathematical Institute, an author of the report. ‘Our new approach, which can be applied to any type of network, is potentially much better than existing methods at identifying what makes a 'community' within a network and at tracking how such groupings evolve over time.’

Until now, it was only possible to detect communities using computer algorithms in very special cases – in particular, only in networks that are treated as if they don't change over time and as if they have only one type of connection.

The new computational method can be used with what researchers call ‘multislice’ networks, in which each ‘slice’ might represent a social network at one snapshot in time or a different set of connections between the same set of individuals. These ‘slices’ are combined into a larger mathematical object, which can contain a potentially huge amount of data and is difficult to analyse. Previous community-finding methods could only deal with each slice separately, and it was necessary to compare the results obtained from different slices using ad hoc tools (if it was possible at all) and the new method overcomes this key challenge.

‘It's very easy to use ‘ad hoc’ methods and miss something that is potentially interesting or important in such complex networks,’ said Dr Porter. ‘Whilst our new approach doesn't dictate what you will find, it does potentially give you a much better chance of finding interesting connections if they're there.’

• A report of the research, entitled ‘Community Structure in Time-Dependent, Multiscale, and Multiplex Networks’, is published in Science on 14 May, embargoed until 19:00 BST/14:00 EST (US) 13 May 2010.

As advertised on Departamental pages, we remind you about the following seminar:

“On Mean Field Games”

Professor Pierre-Louis Lions
Wednesday 5th May
At 5pm at OMI, Eagle House

Wine reception at 6.00pm to follow 
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Colin Macdonald has been awarded the 2010 SIAM Richard C. DiPrima Prize, making him the 11th recepient of the award.

Jon Chapman, currently the Professor of Mathematics and its Applications and Director of the departmental research group OCIAM, is a former winner, being awarded the DiPrima prize in 1994.

The SIAM Richard C. DiPrima Prize is awarded every other year to a junior scientist for outstanding research in applied mathematics based on the doctoral dissertation.

Oxford DPhil student Muhammad Imran Qureshi received one of 4 prizes "for best talks given by students" at the Maths 2010 meeting (combined BMC/BAMC), held 6-9 April 2010 in Edinburgh. There was a total of 90 talks given by students at the meeting. Mr Qureshi is a student of Balazs Szendroi; his talk was entitled Some new families of Calabi-Yau 3-folds in weighted flag varieties.

Dr David Acheson has been elected President of the Mathematical Association for 2010-11.

We are currently recruiting a Departmental Lecturer in Mathematical Finance.

This year's Nomura Lecture will be given by John Campbell, Harvard College Professor, Harvard University, on Thursday 20th May, 2010. The lecture will begin at 5pm (with refreshments before hand at 4.30pm) and the venue is The Nelson Mandela Lecture Theatre, Said Business School.
All are welcome.

Title: The Changing Risks of Government Bonds

Abstract: The covariance between nominal bonds and stocks has varied considerably over recent decades and has even switched sign. It has been predominantly positive in periods such as the late 1970s and early 1980s when the economy has experienced supply shocks and the central bank has lacked credibility. It has been predominantly negative in periods such as the 2000s when investors have feared weak aggregate demand and deflation. This lecture discusses the implications of changing bond risk for the shape of the yield curve, the risk premia on bonds, and the relative pricing of nominal and inflation-indexed bonds.

On Thursday, March 11, 2010, two physicists-GP-B Principal Investigator, Francis Everitt, from Stanford and Sir Roger Penrose from Oxford-will jointly be awarded the ninth annual Trotter Prize at Texas A&M University. The annual Trotter event includes both a cash prize to the recipient(s) and an endowed public lecture series.

The Trotter Prize in Information, Complexity and Inference is awarded annually for pioneering contributions to the understanding of the role of information, complexity and inference in illuminating the mechanisms and wonder of nature.

The Trotter Lecture seeks to reveal connections between science and religion, often viewed in academia as non-overlapping, if not rival, worldviews. For this year's Trotter Lecture, both Everitt and Penrose will speak on this topic. Everitt's talk, entitled "Mystery in Science, Reason is Religion," will explore how mystery and moral discipline permeate both science and religion and how reason affects each in the context of Christian faith. Penrose's talk, entitled " Did the Universe Have a Beginning?" will explore the philosophical implications of conformal cyclic cosmology (CCC), which Penrose offers as an alternative scheme to the prevailing Big Bang theory.