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Dr Rowan Williams, the former Archbishop of Canterbury, is among this term's Humanitas Visiting Professors at Oxford University.

Dr Williams will be giving two lectures in his capacity as Humanitas Visiting Professor in Interfaith Studies, as well as taking part in an 'in-conversation' event with Jon Snow.

Acknowledged internationally as an outstanding theological writer, scholar and teacher, Dr Williams has been involved in many theological, ecumenical and educational commissions. He has written extensively across a wide range of related fields of professional study, including philosophy, theology (especially early and patristic Christianity), spirituality and religious aesthetics. He has also written throughout his career on moral, ethical and social topics and, after becoming archbishop, turned his attention increasingly on contemporary cultural and interfaith issues.

Dr Williams' programme begins on 24 January with his first lecture ('Faith, Force and Authority: does religious belief change our understanding of how power works in society?') followed by the in-conversation event. He will then give his second lecture ('Faith and Human Flourishing: religious belief and ideals of maturity') on 29 January.

Also visiting Oxford this term is General Michael Hayden, as Humanitas Visiting Professor in Intelligence Studies.

General Hayden is the former director of the National Security Agency and Central Intelligence Agency (CIA). As director of the CIA, General Hayden was responsible for overseeing the collection of information concerning the plans, intentions and capabilities of America's adversaries; producing timely analysis for decision makers; and conducting covert operations to thwart terrorists and other enemies of the United States.

Before becoming director of the CIA, General Hayden served as the country's first Principal Deputy Director of National Intelligence and was the highest-ranking intelligence officer in the armed forces. He currently serves as a principal at the Chertoff Group, a security and risk management advisory firm, and as a Distinguished Visiting Professor at George Mason University.

General Hayden will be lecturing on 10 and 12 February with talks titled 'My Government, My Security and Me' and 'Terrorism and Islam's Civil War: Whither the Threat?' respectively.

Humanitas is a series of Visiting Professorships at the Universities of Oxford and Cambridge intended to bring leading practitioners and scholars to both universities to address major themes in the arts, social sciences and humanities.

Created by Lord Weidenfeld, the programme is managed and funded by the Institute for Strategic Dialogue with the support of a series of generous benefactors and administered by the Oxford Research Centre in the Humanities (TORCH).

What's behind the engines that keep planes in the air?

In a new animation launched today, Oxford University engineers take viewers on a tour around the modern jet engine, exploring the qualities that enable fast and efficient air travel.

The animation, 'Jet Plight', is the latest in a series of videos from Oxford Sparks, a web portal giving people access to some of the exciting science happening at Oxford University.

It follows the adventures of Ossie, a friendly green popsicle who has previously been on a spin around the brain, met a rogue planet and negotiated a volcano's plumbing system, as well as investigating heart attacks, the coldest things in the universe, and the Large Hadron Collider.

I caught up the project's scientific adviser, Professor Peter Ireland of Oxford University's Department of Engineering, to find out more about the science behind the animation.

OxSciBlog: What makes jet engines such a fascinating area of research?
Peter Ireland: Many things - for example, the way in which engines are designed to deal with extremes of pressure, temperature and rotational speeds. The gas flow inside the turbine needs to be precisely controlled and this means we need to understand the way it behaves.  We use sophisticated computer models to predict these flows and experiments to understand the flow physics.
 
OSB: What made you decide to get involved with Oxford Sparks?
PI: I want people to see that engineering is an exciting, important subject and to encourage more schoolchildren to consider it as a career. There’s a real shortage of women going into engineering, so if this animation causes even one girl to consider a career in engineering then I’d consider it a success. There are fantastic opportunities for young people in this country, with a great demand for engineering graduates. Aerospace manufacturers are always looking to recruit new engineers to fulfil their ever-growing order books.

OSB: Why is it so important to make blades from a single crystal of metal?
PI: If you steadily try to stretch most metals, over time they extend slowly - or creep. Creep gets much easier at high temperatures, and the way a blacksmith works high temperature steel is a good example of how metal deformation gets easier with heating. Most metals are made of tiny individual crystals, and creep often occurs at the boundaries between crystals. Creep is reduced if the metal part is made of a single crystal.
 
OSB: What makes Oxford's turbine test facilities so special?
PI: Our research has focussed on understanding the way in which engine parts perform - especially the turbine. Over the last 40 years, we have perfected computer methods and experiments to understand and predict the performance of this amazing part of the engine. Our facilities allow us to study the heat transfer in great detail and to simulate real conditions using scale models. There are special equations in what we call ‘dimensionless groups', where certain parameters behave the same at all scales. For example, you could put an Airfix-size Concorde in a Mach 2 wind tunnel and see the same patterns of pressure and shock structures that you would see in the real thing – although you might need to strengthen the model if it’s made from thin plastic!
 
OSB: What impact might your group's work have on making 'greener' engines?
PI: We have helped to make the engine more fuel-efficient by reducing inefficiencies caused by aerodynamic losses and cooling air. The ultimate aim of most of our research is to reduce CO2 emissions from jet engines.

OSB: Do you expect to see any major changes in jet engines over the next few decades?
PI: Yes. The engine architecture used for passenger Civil Aircraft, such as the Boeing 787 and Airbus 380, has been stable for many years. I think engine configuration will change significantly for future generations of aircraft. We can make engines more efficient by increasing the proportion of air passing through the propellers outside of the core jet intake, called the ‘bypass ratio’. However, these efficiency gains are reduced as we need to build ever-larger casings, called ‘nacelles’, around the propellers that add weight and drag. A new generation of engines called ‘open rotor’ are designed to work without needing nacelles, offering greatly improved efficiencies. I look forward to seeing these technologies develop in years to come.

Reviving a gene which is 'turned down' after birth could be the key to treating Duchenne muscular dystrophy (DMD), an incurable muscle-wasting condition that affects one in every 3,500 boys.

Boys with DMD have difficulty walking between the ages of one and three and are likely to be in a wheelchair by age 12. Sadly, they rarely live past their twenties or thirties.

For the past 17 years, Professor Dame Kay Davies and Professor Steve Davies at Oxford University have been working on treatments for the condition, which is caused by a lack of the muscle protein, dystrophin.

In recent months they have found a number of new groups of molecules which can increase the levels of utrophin, a protein related to dystrophin. Greater levels of utrophin can make up for the lack of dystrophin to restore muscle function. They have worked with Isis Innovation, Oxford’s technology transfer arm, to strike a deal with Summit, a drug development company with a focus on DMD.

'Duchenne muscular dystrophy is a devastating muscle wasting disease for which there is no known cure,' said Professor Kay Davies. 'These boys all still have the utrophin gene – and that’s what we’re taking advantage of. In adult muscle, utrophin is present in very low amounts, and we aim to increase the amount to levels which will help protect the muscle in these boys.

'If this approach, called utrophin modulation, really works as we hope, we could treat these boys very early on, increase their quality of life and length of life. They would walk for longer.

'This is a disease that really needs effective treatment – it takes many families by surprise because of the high new mutation rate which occurs in dystrophin protein such that boys with no family history of the disease can be affected.'

The Oxford team have been working with Summit, an Oxford spin-out company, to develop their first drug for Duchenne Muscular Dystrophy, SMT C1100. In 2012, SMT C1100 successfully completed a Phase 1 trial which showed the drug could safely circulate through the bloodstreams of healthy volunteers. It is now about to enter clinical trials in people with DMD.

Professor Kay Davies said: 'In our ideal world the first molecule we developed with Summit plc, SMT C1100, will have a beneficial effect in these patients. But although SMT C1100 looks promising, we asked ourselves - can we find other drugs that might do even better?'

The new deal will see a research collaboration formed between the University of Oxford and Summit to further the development of the new set of molecules.

Professor Steve Davies said: 'We want to ensure that this utrophin modulation therapeutic approach has the best chance of success in the shortest time for treating Duchenne Muscular Dystrophy. We are delighted to join forces with Summit plc in developing, alongside first in class SMT C1100, these back-up and potentially best in class candidates.'

Tom Hockaday, Managing Director of Isis Innovation, said: 'Isis is delighted to support Professors Kay Davies and Steve Davies in this vital work. Having a number of potential drug candidates in development greatly increases the chances of reaching the ultimate goal, which is to successfully treat this incurable disease.'

Glyn Edwards, Chief Executive Officer at Summit, said: 'The alliance provides access to differentiated classes of utrophin modulators, potentially with new mechanisms, to complement our clinical candidate SMT C1100 while also establishing a strong drug pipeline for the future. Importantly, the alliance cements our long-term relationship with two scientific leaders at the University of Oxford.'

Michael Faraday or Michael Flatley? Science or dance? The latest Science video competition shows that the two go hand in hand...

A creative video on sperm competition [watch the video], which sees swimming cap-clad sperm chasing a water-borne egg through a lake, scooped top prize in Science magazine's 2013 Dance your PhD contest.

The film was created by Dr Cedric Tan from Oxford University's Department of Zoology, who has previously won the 2012 NESCent Evolution Video Contest and the Biology category of Science's 2011 Dance your PhD contest.

I caught up with Cedric to find out how he took his ideas from the lab to the lake...

OxSciBlog: Could you tell us a little more about the concepts shown in the film?
Cedric Tan: There were two main ideas in this film. First, a male invests more sperm in the females that have mated with his brother. This was an interesting finding in the red jungle fowl where females mate with multiple males, creating episodes of competition between sperm of different males. Second, the female ejects a higher proportion of sperm from the brother of the first male mate and favours the sperm of the non-brother, facilitating a higher fertility by the non-brother's sperm.

OSB: Why are non-brother sperm more successful, and are there evolutionary reasons for this?
CT: The non-brother sperm is probably more successful as a result of female preference and ejection of a larger proportion of sperm from any of the brothers. We are not sure why females behave as such but a probable reason is that the females are mating with the male that is different from the brothers in order to increase the genetic diversity of the offspring.

OSB: What challenges did you face trying to explain these concepts through dance?
CT: A major challenge is definitely the fact that dance is a non-spoken art and we had to use our bodies to convey the scientific idea. However, through movements inspired by chickens and sperm, we were able to illustrate sexual behaviour of the chicken and some interesting characteristics of sperm biology.

OSB: Could you tell us a bit about the accompanying music?
CT: The two original music and lyrics pieces were written by Dr Stuart Wigby, my former supervisor. The first piece 'Animal Love' is about the variety of sexual behaviour across different animal species. The second piece 'Scenester' is a piece about a girl who keeps changing her ways and males trying to keep up with her, which is especially apt for illustrating sperm competition.

OSB: How long did it take to plan, choreograph, shoot and edit?
CT: This idea was conceived last summer after I finished the previous video on 'Less Attractive Friends'. However I only started in June 2013 to plan, with the help of my Producer Sozos Michaelides and co-producer Kiyono Sekii. Choreography and training of the dancers was done with my co-choreographer Hannah Moore and lasted 4 weeks. Choreography came along quite readily as I was working simultaneously on my field experiments, in which I was deriving inspiration from the chickens and the sperm under the microscope. Hannah also worked very closely with me on synthesising sperm and chicken movements with sports actions.

After the intense training and for the following three weeks, the Director of Photography, Xinyang Hong, shot the dancing at various places, from Port Meadows to Hinksey Lake. I took about 3 weeks to edit the videos and that was a pain but looking at the outcome, I must say it was all worth it!

OSB: Do you have any plans for another video next year?
CT: Yes of course! It will sexier, stickier and sizeably bigger, and in the style of a musical. But the idea is a secret... I am already excited about creating this new piece!

OSB: Finally, how did you convince so many people to dress up as sperm and jump into a freezing lake?
CT: It took lots of bribing with food. Kiyono also religiously brought flasks of hot drinks for the dancers every time we had pool/lake filming. As for the costume, many of the sperm complained a lot, I just had to buy more food.

The video was funded by Green Templeton College, Oxford, The Edward Grey Institute of Field Ornithology and the European Society for Evolutionary Biology.

Over the last four years, solar cells made from materials called perovskites have reached efficiencies that other technologies took decades to achieve, but until recently no-one quite knew why.

Since perovskite was first used in 2009 to produce 3% efficient photovoltaic (PV) cells, scientists have rapidly developed the technology to achieve efficiencies of over 15%, overtaking other emerging solar technologies which have yet to break the 14% barrier.

Scientists at Oxford University, reporting in Science, have revealed that the secret to perovskites' success lies in a property known as the diffusion length, and worked out a way to make it ten times better.

'The diffusion length gives us an indication of how thick the photovoltaic (PV) film can be,' explains Sam Stranks, who led the discovery in Henry Snaith's group at Oxford University's Department of Physics. 'If the diffusion length is too low, you can only use thin films so the cell can't absorb much sunlight.'

So why is the diffusion length so important?

PV cells are made from two types of material, called p-type and n-type semiconductors. P-type materials mainly contain positively-charged 'holes' and n-type materials mainly contain negatively-charged electrons. They meet at a 'p–n junction', where the difference in charge creates an electric field.

The cells generate electricity when light particles (photons) collide with electrons, creating 'excited' electrons and holes. The electric field of the p–n junction guides excited electrons towards the n-side and holes towards the p-side. They are picked up by metal contacts, electrodes, which enable them to flow around the circuit to create an electric current.

'The diffusion length tells you the average distance that charge-carriers (electrons and holes) can travel before they recombine,' explains Sam. 'Recombination happens when excited electrons and holes meet, leaving behind a low-energy electron which has lost the energy it gained from the sunlight.

'If the diffusion length is less than the thickness of the material, most charge-carriers will recombine before they reach the electrodes so you only get low currents. You want a diffusion length that is two to three times as long as the thickness to collect almost all of the charges.'

The thickness of a solar cell is always a compromise – if they're too thin they won't absorb much light, but if they're too thick the charge carriers inside won't be able to travel through. Longer diffusion lengths allow for more efficient cells overall, as they can be made thicker without losing as many charge carriers. Scientists can get around this by arranging cells into complex structures called 'mesostructures', but this is a time-consuming and complicated process which has yet to be proven commercially.

Previously, researchers were able to get mesostructured perovskite cells to 15% efficiency, using a perovskite compound with a diffusion length of around 100 nanometres (nm). But by adding chloride ions to the mix, Henry's group achieved diffusion lengths over 1000nm. These improved cells can reach 15% efficiency without the need for complex structures, making them cheaper and easier to produce.

'Being able to make 15% efficient cells in simple, flat structures makes a huge difference. We've made hundreds just for research purposes, it's such an easy process. I expect we'll be seeing perovskite cells in commercial use within the next few years. They're incredibly cheap to make, have proven high efficiencies and are also semi-transparent. We can tune the colour too, so you could install them in aesthetically-pleasing ways in office windows.'

That perovskite cells are showing commercial potential after such a short time is a testament to their fantastic properties. We could well be seeing perovskite cells with efficiencies of 20-30% within the next few years, offering the same power as standard silicon-based cells at a fraction of the cost.

'Now is a truly exciting time to be working in the field,' says Sam. 'It's such a rapidly-emerging field, I expect to see it evolve even further over the next couple of years. What's incredible is that all of these advances have been made in academic environments so far, but it won't be long before industrial manufacturers start looking at perovskite cells as serious contenders.'