Header Image - Science City

Lookahead maths predicts credit risk

It usually appears in the small print: “The company will contact credit rating agencies in its consideration of your application.” For older products it is easy for lenders to compare your profile against historical data to rate your suitability. Mathematicians have now devised a credit scoring technique for newly launched products where little data is available for analysis.

“There are basically two classes of customer,” notes Professor David Hand from the Department of Mathematics at Imperial College, London. “There are the ‘bads’ – those that default in some way before the end of the loan term – and the ‘goods’ who keep up their payments. Once you have accumulated a body of data for a loan product, you can build some sort of model that uses application form data and credit bureau ratings to classify applicants as good or bad.”

But for new products no data are available. Worse still, you normally have to wait until the end of the loan term before you know that a customer really is ‘good’. Professor Hand has applied a branch of statistics called survival analysis to borrowers’ records that should help banks score applicants more accurately.

“Survival analysis takes into account customers who are likely to default before the end of the loan term,” Professor Hand explains, “not just the customers who have actually defaulted at by the time of the calculation. When we used our survival analysis for lookahead scoring far fewer accepted customers turned bad.”

Professor Hand hopes to further refine his methods. For instance, he wants to allow for the low probability of borrowers going ‘bad’ when reaching the end of the loan term. “Already we have shown that survival analysis, using just a small body of data, is a powerful technique to improve applicant credit scoring for new loan products. It should help lenders accept few ‘bad’ customers and develop more comprehensive predictive models faster.”

Lining up to detect text reuse

People say that being copied is one of the greatest honours, but in the world of journalism it is hard to spot. Researchers say they can now identify which articles are really just rewritten press releases and wire reports. Using a combination of genetic and linguistic analysis, computer-based comparisons will identify plagiarists, and help press agencies track how much their services are used.

“In an age where text is passed around freely, it is important to track originality,” states Dr Rob Gaizauskas from the University of Sheffield. “Examiners and teachers like to know if their students have lifted essays from textbooks; disappointed authors would welcome the chance to prove that the scripts of films are actually taken from the ones they had sent in years before.”

In the context of press journalism, agencies like the Press Association (PA) supply thousands of stories a week to publishers as sources for stories. “Press agencies have a very strong commercial interest in knowing whether or not any given story X that appears in a newspaper is derived directly from a story Y that they put out,” Dr Gaizauskas explains. “If an agency could know this they would be able to plan and charge for their services in a more rational way. They could also focus their journalists’ efforts to cover what the papers are likely to use.”

Leading a team from the Department of Computer Science, Dr Gaizauskas has employed a variety of techniques to compare newspaper articles with PA wire stories. In one approach, the researchers take ’tiles’ – sequences of words cut from one text – and overlay them onto matching sequences in the comparison text. The amount of unmatched text and the average size of the tiles give clues as to the likelihood of derivation.

Another technique involves ‘lining up’ the two texts using a method originally intended to align words in translated passages with those in the source language copy. The number of aligned sentences and the degree of overlap between aligned sentences again indicates potential reuse.

Analysing newspaper stories, Dr Gaizauskas distinguishes which stories are wholly derived, partially derived or not at all derived from PA material. Best results to date show wholly or partially derived stories can be distinguished from non-derived texts with greater than 90% accuracy; the three way classification is more than 70% accurate.

“To improve these results we will require more sophisticated modelling of journalists’ rewriting techniques,” says Dr Gaizauskas. “For example, we need to take into consideration the use of newspaper house style and vocabulary, and allow more for distractors such as quoted speech, which may occur identically in independently written texts.

“Our work will have commercial significance for our collaborator, the PA, and help it to monitor the penetration of its stories in the press. In the long term, however, this could be developed by publishers to spot plagiarism. With a bit more understanding, the same techniques may even help newspapers write their stories. It could show how original materials could be automatically rewritten to fit house styles and other criteria.” Perhaps journalists will leave the rewrites to computers while they go out and find a scoop.

Computer experts open the way to using the web for confidential patient records

Computer experts at Salford University have successfully demonstrated that existing security software can be integrated into systems to enable the Internet to be used to transfer highly confidential patient records between hospitals and GPs’ surgeries in a user-friendly way. The system allows GPs to use standard web browsers to access the data while maintaining the degree of security required for such sensitive information. The researchers are also developing new ways to use such information to help GPs to give their patients a better understanding of their medical condition.

‘Hospitals maintain databases of information on patients with chronic conditions such as diabetes or heart disease, but GPs generally do not have very ready access to this data,’ says Dr Andrew Young, one of the researchers on the project, which is being funded by the Engineering and Physical Sciences Research Council.

Periodically hospitals may print out these records and send them to the family doctor, but GPs are keen to have better access. Furthermore, if GPs want to add something to the records they must send the information by letter to the hospital where it gets typed in, which is not ideal.

While it would be possible to create a direct computer link between the GP and the hospital this is expensive, and for such a system to be universally applicable the same equipment of the same specification would be needed in every hospital.

The advantage of using the Internet is that the infrastructure already exists. However, the big challenge is to make certain that confidential information transferred over the internet remains secure.

The Salford team has successfully launched a pilot scheme with the Hope hospital in Eccles and ten local GPs. A web server has been set up in the hospital, linked to the hospital’s database of patients’ records. A ‘firewall’ has been installed – a dedicated computer that stands between the hospital’s network and the internet. Software in this computer vets everything coming in and out of the system to ensure that any information requested is coming from an authorised source.

‘The software installed across the system gives strong authentication and encryption,’ says Dr Young. ‘The data that flows between the surgery and the hospital is encrypted, so that the fact that the Internet is an untrusted network will not compromise the security of the data. We have had to provide mechanisms to allow the hospital to be 100 per cent certain that requests for information are from valid GPs and that the GPs themselves have access only to the records of patients under their care.’

The researchers are also keen to enable doctors to use the information contained in patients’ records to help patients themselves better understand their condition.

‘One of the things the project wanted to study was the ‘human factors’ of making medical data available to patients – how to give them the information they need in a form they can understand,’ says Dr Young. ‘Initially, we wanted patients to access the information themselves but it seemed few patients wanted to do that. So we have ended up with a three-way consultation with a GP, patient and computer. The GP uses the computer but the user-interface is aimed at the patient. What we want to find out is that if doctors give health-related information to a patient based on the patient’s own medical condition, then this will have more impact on the patient than simple general advice; and will this in turn help the patient make worthwhile changes to their lifestyle?’.

A lot of work has been done by the project team to design a variety of user interfaces and test the way that patients respond to them. ‘Graphs are fine for t

Carbon makes electricity from the sun

Carbon makes electricity from the sun

The sun is our ultimate source of energy, but capturing its rays using solar cells is unsatisfactory. First solar cells are expensive, and even when the sun shines brightly, the amount of electricity produced is small. Research now suggests that carbon, the main constituent of all organic compounds on the earth, at last makes the sun an economical electrical powerhouse.

Solar cells produce electricity when the sun’s energy is absorbed to move electrons into higher energy states. In these excited states, the electrons move through the cell material towards an electrode, generating an electric current.

Today’s commercial solar cells are made from inorganic semiconductor materials, where there is a good match between the energy in sunlight and the energy which can be absorbed by electrons. Recently, though, scientists have discovered that some plastic-like organic materials can also be used to absorb solar light and convert into electricity.

In these organic polymers the absorbed light is converted to an excited, negatively charged electron bound to a positive ‘hole’. This bound electron-hole pair is termed a ‘exciton’.

“In normal solar cells the electron and the hole are not bound as an exciton, and can drift apart to opposite electrodes to develop a voltage. This is the origin of the classical photovoltaic effect exploited in solar cells,” explains Professor Gehan Amaratunga, who leads a research team in Cambridge University. “Therefore, to have a polymer solar cell it is essential that the exciton is split or disassociated so that electron and hole can drift apart to form the negative and positive terminals of the cell. Exciton dissociation takes place best at the junction between the polymer and a metal which accepts the electrons.”

Professor Amaratunga’s group in the Department of Engineering thought that carbon could make a good electron acceptor in the polymer. “We introduced carbon into the body of the polymer in the form of tiny channels which could accept the electrons and allow them to travel to the electrode. It is as if there were electron acceptor sites throughout the entire polymer, and not just at its surface. We used a form of carbon called single wall nanotubes, where carbon atoms arranged in a flat sheet are rolled up to form a tube.”

The researchers sandwiched the polymer-carbon nanotube blend between a layer of aluminium on one side and indium-tin oxide on the other to act as the electrodes.

They found that when illuminated, the cells produced an electric current around two orders of magnitude larger than for a more typical cell made with only the polymer. “These results are very exciting,” says Professor Amaratunga. “It appears that the nanotubes improve the transport of free electrons to the electrodes, opening the way for a new class of photocell with improved performance. You get more electricity for the size of your cell, and being much cheaper, they make solar power more of an economical option.”

These organic solar cells have an energy payback time of as little as three months. In other words, in three months they convert the same amount of energy that is needed for their manufacture. Even though their energy efficiency is only 2-3%, the best solar cells have an energy payback time of five to six years and are far more expensive.

“These new organic cells could be especially important in less developed countries where the initial investment available for developing an electric power infrastructure is limited,” notes Professor Amaratunga.

Perhaps carbon, all too condemned for its polluting effects in soot and greenhouse gases, could contribute to renewable energy production too.

Protecting the brain from stroke

It only takes one small clot to cause a stroke. Blocking a blood vessel in the brain, a clot starves cells of oxygen and thus triggers their untimely death. Now a new drug under investigation appears to protect nerves from damage and increase the chance of a recovery.

“When blood flow to the brain is blocked there is an increase in highly reactive, charged molecules called free radicals,” says Jonathan Marshall from the Comparative Cognition Team in Cambridge University’s Department of Clinical Veterinary Medicine. “These are highly dangerous and can cause nerve cells to prematurely die, so we have been working on a compound that mops up the free radicals and therefore save cells from death.”

Working with drug firm AstraZeneca, Dr Marshall has tested the effects of the drug, NXY-059, in monkeys that have undergone a moderate stroke. The researchers monitored the animals’ ability to perform several tasks that required them to reach for food before and after the stroke. They later took samples from these animals to quantify the extent of brain damage.

“Our experiments show that NXY-059 has substantial protective effects,” says Dr Marshall, “not only at reducing the amount of brain damage we observed in samples, but more importantly, at reducing the functional disability that follows a stroke.”

Dr Marshall adds that the most impressive effect of NXY-059 was to reduce the impairment that monkeys sustained in their arms. “Stroke victims often lose motor function on the opposite side to where the brain damage occurs. The monkeys that received NXY-059 readily used their affected arm at near normal levels 10 weeks after the stroke and were more likely to uses their disabled limb. They did not neglect one side of space as is frequently the case in stroke patients.

NXY-059 did not just enhance the natural rate of recovery but also reduced the long-term disability in these monkeys. This is important; large strokes are associated with permanent disability and poor recovery in humans.”

Dr Marshall is continuing his work looking at treatments for stroke. Recently his research team conducted safety testing for NXY-059 in clinical trials; the compound did not cause any adverse side effects. It is now hoped that large scale clinical trials will begin soon to assess the drug’s efficacy in stroke patients.

“The drug may have valuable applications in a wide range of brain damage,” concludes Dr Marshall, “including head injury and birth complications, and reduce long term disability following stroke. It could really help patients regain their lives and provide substantial cost savings to Health and Social Services.”

Stereotypes that contradict health advice are rare

When it comes to promoting healthier lifestyles, getting past the stereotypes is often a major challenge. Every time you say “Don’t smoke” someone will point to ‘Uncle Norman’, a familiar male figure who ignores medical advice and lives to tell the tale. Suggesting regular exercise provokes a debate on ‘the Last Person’ (you’d expect), who dies at a young age from a heart attack despite taking medical advice and living an exemplary lifestyle.

Researchers from the Medical Research Council Social and Public Health Sciences Unit at the University of Glasgow have now shown that these two stereotypes do exist, but are few and far between.

In a survey of 6000 Scottish men who were first studied in the 1970s and followed up for more than 25 years, they identified a group of 193 overweight, heavy smokers normally considered at high risk from a heart attack. Only half of these survived to the age of 70; around a quarter still died of a heart attack before that age.

Among the ‘low risk’ group of 337 men who had never smoked and who were the correct weight, the mortality rate was very low. Only 12 people, or one in 25, died of heart disease before the age of 70.

The majority of these ‘Last Person’ deaths were associated with other less obvious risks for heart disease, such as poor lung function, diabetes, previous heart disease and poorer social circumstances. Similarly, three quarters of the surviving ‘Uncle Normans’ had protective factors such as being taller and having lower cholesterol levels.

“Our assessment shows that the ‘Last Person’ is indeed a rare occurrence but looms large in public consciousness because such deaths are dramatic, unexpected and premature,” notes Dr Kate Hunt, one of the study’s senior researchers. “In addition to the trauma to immediate families and friends, such deaths often make a large impact locally and nationally through media coverage.”

Dr Carol Emslie, another investigator, adds, “‘Uncle Norman’ is not as common as people think, but it is true that there is a very small group of men who appear relatively immune to coronary disease risks. It is important for health promotion to acknowledge the existence of ‘Uncle Norman’ while emphasising that general healthy living advice is relevant to the vast majority of us.”

‘The Last Person’ and ‘Uncle Norman’ are both real people, but they are both rare. What is more important is the huge difference in coronary mortality between men at high and low risk. Using ‘Uncle Norman’ or ‘the Last Person’ to defend a poor lifestyle is dangerous – they are both outsiders. You should not bet against the established risk factors for heart disease.

Scottish universities give software longer and healthier lives

Sustained funding by the Engineering and Physical Sciences Research Council has assisted researchers at St Andrews and Glasgow Universities to create a new way of building and enhancing computer programs. This can improve efficiency and quality throughout the software industry, including the latest developments on the Internet.

Teams led by Professor Malcolm Atkinson of Glasgow’s Computing Science Department and Professor Ronald Morrison at St Andrews’ School of Mathematical and Computational Sciences have been collaborating for over 15 years to improve the design, construction, maintenance and operation of what they call Persistent Application Systems (PASs). These use software that must evolve over long periods to sustain the applications they support.

‘Most major businesses and public services now depend on their computer software. It is therefore vital that these systems are able to adapt to changing requirements, while continuing to operate reliably and efficiently,’ says Professor Atkinson.

Professor Morrison adds: ‘Developing a major software system is intrinsically complex because it has to control a multitude of tasks in minute detail. This has been made even more difficult by fundamental inconsistencies in the methods used for different aspects, such as programming and database management.’

The Glasgow and St Andrews teams have engineered techniques for a streamlined PAS development environment that overcomes many of these inconsistencies. A key feature of this is known as ‘orthogonality’, a set of design principles which allow programs to handle any type of data, irrespective of how long it has to persist.

An important new long-term EPSRC research project involves the Glasgow team and Sun Microsystems Laboratories in the USA working together to bring orthogonal persistence to Java, Sun’s popular Internet programming system. As part of this project, Cambridge-based Laser-Scan Ltd will examine the value of applying these persistent Java capabilities to its geographical information systems software

EPSRC funding is also enabling Professor Morrison’s group to investigate the use of orthogonal persistence on the World Wide Web. This builds on Napier 88, their pioneering PAS environment, and is exploring the novel concept of ‘hyper- programming’, which facilitates linking new programs to existing data.

The first commercial product based on persistent programming, IT vendor ICL’s ProcessWise Integrator process manager, employs a re-engineered version of the universities’ PS-algol environment, one of their earliest PAS innovations. Professors Atkinson and Morrision have also played prominent roles in projects sponsored by the EU that have greatly assisted their research into orthogonal persistence.

Fat tally at supermarket checkout

They say you are what you eat, but at least only you know how much you ate this Christmas. However, a team of scientists now say that the secret’s out. Just by looking at your supermarket till receipts, they can estimate your consumption of fat and energy intake.

“Over 90% of our food is bought from supermarkets,” says Joan Ransley, Director of the Public Health Nutrition Unit at Leeds University. “We thought that till receipts would tell us lots of information about the nutrition of households.”

The research team studied the four weeks’ worth of receipts from 284 shoppers who said they spent at least 60% of their food bill at Tesco and at other supermarkets. Each member of the household also kept a four-day food diary. All the food eaten at home was weighed and meals eaten elsewhere were recorded and used in the analysis.

The analysis showed that the on average around 36% of a household’s energy intake comes from fat – 3% above the recommended levels set by the Department of Health.

“This pilot study shows a strong relationship between the amount of energy and fat purchased from supermarkets and the amount consumed,” says Dr Ransley. “Assessment of individual food consumption is prone to under reporting and inaccuracies. Therefore, the use of till receipts could be a novel, inexpensive and effective way of evaluating household food consumption.”

Wider studies could assess the nutritional intake of individuals and specific groups in society and examine diet-disease relationships between different geographical regions and countries.

“Supermarkets could play a role in helping us reduce the amount of fat in our diets,” suggests Dr Ransley. “Advances in scanning technology could lead to the development of a ‘fat tally’ of the foods in our trolleys and this could be shown on a graph on the receipt, plotted against the UK recommended levels of energy from fat.” It might be just enough to encourage you to put the triple choc, sticky toffee doughnuts back on the shelf.

Proteins put up a radical defence against ageing

When cells use oxygen to release energy from food, they produce a by-product called superoxide. A highly reactive free radical, superoxide can set off a chain of reactions that damage the structure of the cell and its genes, and can lead to degenerative diseases, ageing, and eventually death. Scientists have now shown that certain proteins can move the harmful superoxide from where it is made to other areas of the cell where it is destroyed safely.

These uncoupling proteins could be important in the natural antioxidant system in cells that guards against damage caused by free radicals and other oxidants. Antioxidants protect cells by eliminating reactive oxygen molecules like superoxide. Other known antioxidants are vitamins E and C. Diets high in fruit and vegetables have strong health benefits partly due to the antioxidant properties of these vitamins.

Oxidative damage has been linked with many ailments such as cardiovascular disease, strokes, autoimmune diseases like arthritis and diabetes, cancer and Alzheimer’s disease. By understanding the role of uncoupling proteins in cells, new treatments for these conditions could be developed.

Commenting on his findings, Dr Martin Brand of the MRC Dunn Human Nutrition, says that the role of uncoupling proteins could be fundamental to protecting against degenerative disease and ageing. “We hope that by understanding their role, we can find potential new ways to prevent or treat free radical linked diseases. For example, we might be able to decrease cellular ageing by using chemicals that switch these proteins on. However, we need to do more research to find practical or medical applications of these exciting new findings.”

The right height for your hips

The right height for your hips

If you want life to begin around 40 then you have to invest during childhood. Many medical conditions that appear in adult life find their beginnings in infancy. A team of scientists from the Medical Research Council’s Environmental Epidemiology Unit has now discovered that people who had poor height gain in childhood are more likely to fracture a hip during adulthood.

Led by Professor Cyrus Cooper of Southampton University, the research analysed over 7,000 medical records of people born between 1924 and 1933 in Helsinki, Finland. The documents recorded their size at birth, growth and living conditions in childhood and their hospital admissions in adulthood.

Statistical analysis showed that the slowest growing children were more likely to suffer a hip fracture. “This is the first time that researchers have had hard evidence that low childhood growth rates are linked to hip fractures in adult life,” comments Professor Cooper. “It seems likely that environmental influences which modify childhood growth are responsible.

“Such influences could include a mother who smoked in pregnancy or who had a poor diet, exposure to infections during infancy and early childhood or low calcium intake and lack of physical activity in later childhood.”

A separate analysis revealed that people who had a mother taller that 1.6 metres were also at increased risk of hip fracture. The researchers finding suggests that fractures might arise from a conflict between the genetic drive for bone growth and the environmental influences which affect the mineralisation of bones during childhood.

Both studies show the importance of a healthy diet in childhood. Just as a wall is more likely to collapse if a builder skimps on cement powder in his mortar, newly formed bone is structurally weak when children do not receive sufficient nutrients to match growth.

As the body of evidence into the childhood causes of adult medical conditions grows, governments and health institutions should begin to see the economic benefits of investing in childhood nutrition as a means of medical prevention for later in life.