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Women areIssue... from Mars, Men are from Venus Inside this Quantum History Why we should all come back to Earth...
A State of Collapse 5
Quantum Medicine Medicine Nature
History Features Features Space
Nature Technology Technology
Space
A State of 17Collapse
5 World It’s a Small
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It’s a Small World Hereditary Yet Infectious Hereditary Yet Infectious Age Before Beauty Age Before Beauty
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9
21 25
Copy and Paste
25
Out of This World
7 A Lost Legacy 7
21
Copy and Paste
16 World Out of This
A Lost Legacy
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2 Editorial 2 Editorial
Wizard of the West
3 News
27 Wizard of the West 27
Imaging in a Flash
3 News 19 Literary Matter 19 Literary Matter
Micromachines
Imaging10 in a Flash
15 Micromachines
10 For Your Eyes Only
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6 For Your Eyes Only 6 Nature’s Palette 20 Men Are From Mars, Women AreFrom FromMars, Venus 11 Men Are Women Are From Venus 11 Going Up in Smoke 25 Going Up in Smoke 25
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Nature’s Palette 20 Whipping Up a Storm 26 Whipping Up a Storm 26
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Bang! Talks to... Simon Singh Bang! Talks to... Simon Singh
28 Riddler’s Digest 13
28 Riddler’s Digest
13 Oxford: CityOxford: of Science City of Science
A Sweet Combination 4 A Sweet Combination 4
Director Director –– Nicola Nicola Davis Davis Editors – Leila Battison Director Nicola Davis and Editors –– Leila Battison and Nicola Nicola Davis Davis Creative Directors – Samuel Pilgrim and Editors Leila Battison and Nicola Davis Creative– Directors – Samuel Pilgrim and Emma Emma Wilkins Wilkins Layout Editor – James Harding Creative Directors – Samuel Pilgrim and Emma Wilkins Layout Editor – James Harding Editorial Team Philip Layout Editor Harding Editorial Team–––James Philip Bennett, Bennett, Jack Jack Binysh, Binysh, Will Will Brandler, Brandler, Jai Juneja, Akshat Rathi, Alisa Selimovic Editorial Team – Philip Jack Binysh, Will Brandler, Jai Juneja, Akshat Rathi,Bennett, Alisa Selimovic Creative Team –– Maria Elizaveta Jai Juneja, Akshat Rathi,Demidova, Alisa Selimovic Creative Team Maria Demidova, Elizaveta Gelfreykh, Gelfreykh, Inez Januszczak, Matthew Jones, Rebekah Kate Pocklington Creative Team – Maria Demidova, ElizavetaPawley, Gelfreykh, Inez Januszczak, Matthew Jones, Rebekah Pawley, Web Editor – Lauren Heathcote Inez Jones, Rebekah Pawley, Kate Pocklington KateJanuszczak, Pocklington, Matthew Sam Roots Blog Editor Jai Juneja Web Editor Lauren Business – ––Celia Bell,Heathcote Philip Bennett, Maria Demidova Business – Celia Bell, Philip–Bennett, Maria Demidova Blog Editor – Jai Juneja Publicity and Distribution Eddie Jacobs, Kate Pocklington Publicity and Distribution – Eddie Jacobs, Pocklington Business – Celia Bell, Philip Bennett, Maria Kate Demidova Publicity and Distribution – Eddie Jacobs, Kate Pocklington i
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Editorial F
rom newspapers to the TV, radio to the internet, science is coming to you. Bursting out across the airwaves are the latest discoveries in outer space, the newest alternatives to fossil fuels and up-to-the-minute reports on the future of electronic gadgets. The spotlight has been turned on science. With this new wave of interest in the world around us, the press has a tricky job reporting the outcome of complex studies. So often the newspaper headlines read ‘Scientists say…’, a turn of phrase certain to annoy chemists and physicists alike. The perception that scientists are scientists whatever their discipline abounds in the media and is usually seen as an unnecessary oversimplification by those working in a lab, who wear the label of biologist or geologist with pride. However, in a sense, the tabloids and TV do have it right. Almost every significant step forward in medicine and technology has been the result of intense collaboration between researchers from a huge range of academic backgrounds. Indeed, although chemists may focus on synthesising one particular drug, they have to use biological knowledge to design it to enter cells and act in the desired manner. Moreover, it is seldom that a researcher will spend his or her whole career in one field—it is more common to move between interests, gaining a wide range of skills and ideas. In this issue of Bang! we have been exploring the connections between disciplines. From using microorganisms in novel building materials, to employing the latest computer science to predict the weather, we bring you the brightest and best from all areas of science. The links between topics can be surprising: who would have thought that X-rays, a radiation source we all learnt about in physics, could be developed to monitor rapid and delicate biological pathways? All branches of science evolve over time, carving unexpected pathways between first theories and latest concepts, winding through many disciplines along the way. Take a peek at our centre page spread to see how Oxford has been involved in some of the most fascinating scientific developments and controversies over the years. It is by linking ideas that science continues to grow and flourish, and we hope that in this issue of Bang! you will share the excitement of making new connections. Nicola Davis & Leila Battison Editors
Art by Samuel Pilgrim. 2
News Brave New Worlds
Making Light Work
Spoonful of Sugar
2011
is the International Year of Chemistry. Celebrating the amazing advances and discoveries made by researchers within the discipline, the high profile journal Nature has showcased groundbreaking work by Oxford chemists led by Professors John Simons and Ben Davis. Using an ultraviolet laser from the Engineering and Physical Sciences Research Council’s (EPSRC) Laser Loan Pool, together with some clever computational work, the interaction of individual sugar units with short protein chains has been investigated in an environment free from solvent molecules. Sugars can exist in two forms— however one is favoured over the other. The origins of this preference (termed the ‘anomeric effect’) are of great interest, because the two different forms interact differently with biological molecules such as proteins. Looking at these interactions in the absence of solvent removes external influences, so that the effect may be probed more thoroughly. What’s more, by understanding the physical mechanisms behind the anomeric effect, and their impact on interactions with other biological molecules, it may be possible for sugar molecules to be tailored for more effective use in drug development and delivery. Nicola Davis
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hysicists working with the University of Oxford’s spin-out company ‘Oxford Photovoltaics’ have developed an innovative new approach to solar cells. These thin film devices are made by screen printing light absorbing dyes onto surfaces such as glass, to which a layer of metal oxides has been added, to harness the sun’s energy. Dr Henry Snaith, whose research group developed the technology, said “One of the great advantages is that we can process it over large areas very easily”.
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These new solar cells are brightly coloured and non-toxic.
Current devices are expensive and often compromised by the scarcity of the materials used; the new technology gets around these problems by utilising cheap, readily available materials and removing the need for a liquid component to the cell. It is thought that the manufacturing costs of these devices could be up to 50% lower than the most up to date alternatives—an encouraging step in the hunt for viable green energy. These new solar cells are brightly coloured, non-toxic, and show promising conversion efficiencies—a measure of how well the device turns solar energy into electricity. As a result they may be used in the future as glazing materials for modern housing. Kevin Arthur, who heads up Oxford Photovoltaics, said “This technology is a breakthrough in this area. We’re working closely with major companies in the sector to demonstrate that we can achieve their expectations on economic and product lifetime criteria”.
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ASA scientists have recently reported the discovery of over 1200 exoplanets—planets orbiting other stars—including 54 which may be suitable for life. The Kepler mission launched in March 2009, with the main task of searching for alien worlds. After just a few months of observation, the project yielded breathtaking results. Hundreds of planets were detected by the space telescope, including 68 that are the same size as the Earth. The detection process is simple: the telescope is pointed at a star, and the intensity of light coming from it is measured over a period of time. Any planets that are orbiting will cause a minor eclipse as they pass between the star and the telescope (known as a transit), in turn causing a drop in light intensity. The magnitude of the drop will correspond to the size of the planet, and the duration of the eclipse will be proportional to the orbit period and the distance from the star. These results would not have been possible without the collaboration of Oxford scientists at the Department of Physics. Researchers there have developed planethunters.org, which allows ‘online stargazers’ to identify these alien eclipses,. So far, fascinated members of the public have helped to identify over 90 orbiting exoplanets from the Kepler light curves, highlighting the overwhelming power of such citizen science projects. The achievements of the mission continue to grow, and these exciting preliminary results are just a hint of the many thousands of worlds in our galaxy that are yet to be discovered. Who knows, maybe some of them are looking back Leila Battison
Nicola Davis Art by Leila Battison. 3
A Sweet Combination
How the humble honey bee is creating a buzz in the world of genetics
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umans have used bees for millennia. So precious to the ancient Egyptians was honey that they entombed it in the pyramids, a gift to their revered dead. However, until recently attempts at understanding honeybee genetics had been fairly modest. Even the ‘Father of Genetics’, Gregor Mendel, only got as far as creating some very bad tempered hybrids before concluding that pea plants were much more suitable subjects for his studies. Now though, as the ‘Genomics Revolution’ continues to take hold, the biology of the honeybee is being probed in more
detail than ever before by researchers from a wide range of fields, from molecular biology to anthropology. In 2006 the first completed draft of the genome—the entire genetic information—of Apis mellifera, the western honeybee, was released, creating a huge buzz in the research community—and for good reason. As the main pollinator of insect-pollinated crops, the honeybee has immense economic importance, and without them our diets would be very much sparser. We have more reasons to be interested in bees though. Whilst we humans flatter ourselves that we are by far the most advanced creatures on the planet, other life forms display impressive sophistication, with bees coming very high up the list. As the only non-primates to use a symbolic language to communicate, they live in breathtakingly complex ‘eusocial’ colonies. These communities have striking similarities with the social groups of numerous primate species, including our own. The hive works communally to care for offspring and defend the colony. Even sourcing sustainance is a team effortwith bees indicating the direction of food
to each other by the affectionately termed “waggle dance”. Honeybees therefore act as model systems for our own communities and interactions and are hence ideal for helping us answer questions about sociality. How did it arise? At the genetic level, what makes social life forms special? Do honeybees share specific genetic features with other eusocial animal groups? The genome sequence has provided a firm foundation for studies which aim to provide answers to these questions. Developmental biology is another field which will benefit from the publication of the bee genome. Already, data from the genome has been used to answer a mystery which has long puzzled beekeepers and scientists alike—the way in which royal jelly, when fed to larvae, causes them to become long-lived, large, reproductive queens rather than short-lived, small, sterile ‘default’ workers. Royal jelly, the study reveals, causes changes to DNA itself. Although the units which make up the DNA remain the same, the addition or removal of methyl groups (CH3) to the DNA can affect the extent to which genes are switched on or ‘expressed’. Moreover, this ‘epigenetic’ modification of DNA can be inherited through cell divisions, and is now recognised as an immensely important factor in development. In
the two castes. Further analysis of these genes will no doubt lead to more detailed understanding of their roles in creating and maintaining the differences between queens and workers. In addition, this work has also revealed that methylation can modulate not only how active a gene is but even the form or type of protein encoded, a mode of regulation hitherto completely unknown in any organism.
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As the only nonprimates to use a symbolic language to communicate, they live in breathtakingly complex ‘eusocial’ colonies.
Another fascinating insight into bee biology from the genome sequence is the accompanying data on gene expression. It has been known for decades that the tasks performed by bees vary according to age; young bees tend to stay in the hive and care for the developing larvae while their older nestmates fulfil the colony’s foraging needs. Only now can we see that these different tasks are mirrored at a genetic level by changing the activities of various genes. Genes, it would seem, are central to the dayto-day behaviour of bees. The publication of the honeybee genome was just the start of a flood of information about this enthralling creature and the results of new studies are rapidly springing forth. There is no doubt that the bee genome has many more secrets to give up; it is clear there is much more to bees than honey!
queens, it seems, the distribution of methyl groups is very different to that in workers, with over 500 genes being differentially methylated between 4
Charles Brabin is a 4th year D.Phil. student, studying the molecular genetics of cell proliferation and differentiation in the nematode C. elegans (roundworms). Art by Elizaveta Gelfreykh.
It’s a Small World
Taking a quantum leap in modern computing
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he advent of modern computing came startling quickly, but had been in gestation for over a hundred years. In the early 19th century, Charles Babbage designed the first ‘programmable’ computers based on thousands of hand cranked gears, yet by the start of the 20th Century, analogue electronics were achieving increasingly sophisticated calculations. During the mid to late 20th Century, semiconductor transistors went from laboratory oddities to ubiquitous commodities, revolutionising the modern world in the process. Now they appear in everything from washing machines to university supercomputers. In 1965, Intel co-founder Gordon E. Moore published a paper modelling the rate of development of computer hardware, which stated that the number of transistors that could be placed on an integrated circuit had doubled approximately every two years. Somewhat surprisingly, this observation continued to hold for the following years, and soon the fulfilment of ‘Moore’s Law’, as it came to be known, was used as a measure for the success of computer manufacture. To keep the pace set by Moore’s Law, improvements to traditional computers are continually proposed. Optical fibres, in which light is used to transmit data, have increased broadband internet speeds across the country, replacing electrical wires. Graphene, a chicken wire of carbon, one atom thick, has unique material properties that are only just being explored, and could revolutionise microchip design. However, all of these technologies are based on the classical design of a computer. To increase the power of such electronic devices, the circuits are getting smaller, down to atomic scales. Unfortunately, this is where classical physics begins to break down, and so traditional chip design becomes inadequate. At the atomic level we rely on quantum mechanics instead to describe the behaviour of
atoms, explaining the uncertainties and non-ideal performance of devices on the quantum scale. But can we use quantum mechanics to our advantage? Is there a more fundamental improvement we could make? Computing relies on processing digital units of information known as bits (represented mathematically by 0’s or 1’s). In its simplest form these bits could be represented as a particle being in one position or another, or as a light switch being on or off. Quantum mechanics permits a strange property called superposition which allows the particle to be in both positions at the same time, as long as it’s not observed—as if the switch is both on or off simultaneously. If we now use this quantum particle as our unit of information, it can be both 0 and 1 at the same time and is known as a quantum bit or ‘qubit’.
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Moore’s Law may not hold for much longer for semiconductor based computers, but the quantum revolution could supersede it.
In computing, 8 regular bits can represent any whole number 0 to 255, whereas 8 qubits in superposition can represent all 256 numbers simultaneously. If we intended to perform a calculation on each number, classically we would need to perform 256 different calculations (one per number). But since the qubits represent all the numbers at the same time we can effectively perform the calculation on every number at once. Unlike the current computers, which are based on electrons in silicon transistors, no standard method for constructing a quantum computer currently exists. Experiments have been performed demonstrating that these theoretical 5
musings can be physically realised, but the form in which they should be implemented has yet to be decided. And if the quantum computer is to become an everyday reality it has major hurdles to overcome. So far prototypes can only perform simple calculations, and they are susceptible to decoherence, a problem in which the fragile superposition of the qubits is destroyed due to interactions with the environment (see ‘A State of Collapse on p 20). Furthermore, a standard microchip stores billions of bits at any one time. In comparison, cutting edge quantum experiments have only managed to control 12-qubits. Clearly there is still a long way to go. Quantum computing could improve on its classical analogue to advance technology to unimaginable regimes of speed, power and versatility. Moore’s Law may not hold for much longer for semiconductor based computers, but the quantum revolution could supersede it. The battle of human ingenuity against the physical limitation of computation started slowly and has exponentially increased for over half a century. Can we keep up the pace? Philip Sibson is a 3rd year undergraduate in Engineering at Exeter College. Art by Sam Roots.
For Your Eyes Only
Revealing the latest gadgets for enhancing vision
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he World Health Organisation defines blindness as having visual acuity of less than 20/400. This means that objects visible to the average person from 400 feet are only seen from 20 feet, if at all. Over forty million people worldwide are affected by blindness according to this definition. However, a team led by Dr Eberhart Zrenner, working at the University of Tübingen in Germany, have recently developed a prosthetic chip which could dramatically reduce the numbers of blind sufferers.
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After the implantation of a 3x3 mm array of 1500 microphotodiodes into three trial patients, all regained some sight.
Retinitis Pigmentosa and Age Related Macular Degeneration are two of the leading causes of impaired vision. Both of these diseases act by damaging photoreceptor cells on the retina of the eye, preventing the conversion of light into a nervous signal. To compensate for the loss of photoreceptors, synthetic microphotodiodes are implanted into a patient’s retinal photoreceptor layer. In these microphotodiodes, light knocks electrons out of their atomic orbit, generating ‘free electrons’ that can flow, thereby creating a current. By converting light into electric signals, microphotodiodes stimulate bipolar cells (sensory nerve cells) directly, rather than by chemical transmission which our natural photoreceptors use. This allows the signal to be propagated to the visual centres in the brain via the optic nerve. After the implantation of a 3x3 mm array of 1500 microphotodiodes into three trial patients, all regained some sight; they could recognise simple objects such as cutlery and a mug, as well as basic shapes roughly ten centimetres high.
they require the other structures involved in vision, such as the optic nerve, to be functional. Further, while they have much greater acuity than many other visual prosthetics, they still only confer 38x40 pixels of resolution. The resolution of two fully functioning eyes is measured in megapixels. In order to work around other causes of blindness, different visual prostheses have been proposed, showing amazing variety in their design. Perhaps the most intuitive are a system of cameras with wires that project to artificial electrodes planted on the visual cortex of the brain, directly stimulating the region and producing images. Other prostheses, working by sensory substitution, include a microelectrode array that stimulates the tongue to give an impression of the shape of objects in the visual field. Another technology is the vOICe system, which translates images from a camera on sunglasses into sound that is played into the ear. The visual surroundings are mapped so that the greater the height of an object, the higher the pitch heard and the brighter the object, the louder the sound. After practice, this can give the equivalent of 60x60 pixels of vision. What is perhaps most interesting about these kinds of
Microphotodiodes, while offering simple solutions to blindness, still have some limitations. Primarily 6
prosthetics is how their function improves with use, due to neural plasticity—the ability of structure and function of brain regions to change with experience and use. fMRI scans from a study by Dr Amir Amedi and others at the Hebrew University of Jerusalem have shown that the area of the brain that usually responds to vision and touch, is activated in vOICe users’ brains while ‘looking’ at recognisable objects by receiving auditory cues. Neural prosthetics are still in their infancy, but we should remain optimistic that visual prostheses will soon obtain the acuity of a working visual system. Moreover, future interactions between technology and the nervous system may help to restore function to sufferers of a variety of other disabilities. Robert Hickman, 1st year undergrad uate reading Physiological Sciences, at St Hugh’s College. Art by Emma Wilkins.
Women are from A Lost Mars, Legacy Men are from Venus Why we shouldfoundations all come back to Earth... Exposing the Islamic of modern science
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he 9th century philosopher, Al- astronomers were able to make Euclid and Ptolemy believed that the Kindi captured the Islamic quest observations that refuted the earlier eye emitted rays of light to illuminate for knowledge perfectly when he said, Greek theories on planetary motion. objects allowing us to see; whilst “It is fitting for us not to be ashamed of Although they did not make the leap Aristotle was a proponent of the idea acknowledging truth and to assimilate to a model of the solar system with that objects had a physical form that it from whatever source it comes to the Sun as the central body, Islamic entered the eye. Using a pin-hole us. There is nothing of higher value scholars disproved many Ptolemaic camera, Ibn al-Haytham than truth itself. It never cheapens ideas such as the idea that was able to or abases he who planetary show that seeks. After the motion was images are fall of the Roman Islamic astronomers perfectly formed from Empire, Europe brought an circular. the light was thrown into accuracy and precision reflected the Dark Ages. to the field that is Algebra and by objects. Meanwhile, in impressive even by algorithm are Importantly, the Islamic world, today’s standards. both Arabic he noticed science and words that are that this technology were derived from picture was thriving. This was the Islamic Golden al-Khwarismi’s work (algorithm inverted, Age, which extended from the 7th to stemming from the Latinisation of his thus the 13th century and paved the way name). A 9th century Islamic scholar, indicating that light for the Western enlightenment. he devised algebra by fusing the travels in straight lines, and the Greek and Indian numerical systems observation that it changed according There are certain aspects of Islam and presented his ideas in ‘Kitab al- to changes in the outside world that require precise astronomical Jabrwa-l-Muqabala‘ (al-Jabrwa being confirmed that the image was indeed knowledge. For instance, morning the origin of the word algebra). At a projection of the outside world. By and evening prayers take place at the time, Greek mathematics dealt making parallels between this camera dawn and dusk; precisely defined mainly with geometry (shapes and their and the human eye, he correctly as the times when the Sun is 18° properties theorised that the below the horizon. As a result, Islamic such as pupil was acting astronomers brought an accuracy and volume and Ibn Sina’s as the aperture, precision to the field that is impressive area), whilst revolutionary ideas with the image even by today’s standards. Al-Battani in India the included the use of projected onto the was one such scholar, calculating the ten-symbol clinical, randomised back of the eye for length of the solar year to obtain a time decimal trials for drug testing and processing by the within two minutes of modern values. system had evidence-based medicine. brain. developed, Using the astrolabe to calculate making Ibn Sina was an latitude and triangulate position, and calculations much simpler. 11th century polymath an armillary sphere to model the orbits Al-Khwarismi’s algebra who wrote groundof celestial bodies, introduced the concept of breaking treatises on Islamic treating numbers as objects. medicine such as ‘The By disregarding the actual Book of Healing’ and numerical value of these ‘The Canon of Medicine’. objects and replacing them The latter was used in with symbols, general European universities equations could be used well into the 17th century. to perform a function on any Its revolutionary ideas numerical system. included the use of clinical, randomised trials Ibn al-Haytham, born in 965 AD, for drug testing and evidencewas motivated by the Islamic notion of based medicine. He brought shukuk (doubt)—the underlying driving together the world’s knowledge on force behind the scientific method. healthcare and contributed significantly In his ‘Book of Optics’ he was able to the creation of medicine as a subject to combine the two predominating of study. One may wonder why the theories on the workings of the eye. Islamic world today is not at the
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1241 AD First European pharmacy in Trier, Germany.
1088 AD First European university opened in Bologna.
850 AD
Establishment of the first university, with an undergraduate and graduate system that influences modern universities today.
763 AD First hospital was opened by order of the reigning Abbasid caliphs.
754 AD First drug store and pharmacy opened in Baghdad.
forefront of science and why many modern scientific theories are not as widely accepted there. From the mid13th century the Islamic Empire began to decline and ensuing wars resulted in the destruction of important texts. Moreover, with the discovery of the New World in 1492, the flow of money and gold went west through Spain and Italy.
and prosperity in the Islamic parts of the world meant that scientific progress was arrested. Today there is some reluctance to accept certain ideas that are seen as “Western philosophy� rather than true science.
Subsequently, science thrived in those parts of the world. The development of modern science in the West was organic and the incremental changes in ideas were slowly assimilated and accepted. In contrast the lack of peace
In recent years, Muslim scientists have once again begun making significant contributions to modern science; a notable example being the physics Nobel Laureate Mohammad Abdus Salam with his work on unifying 8
the weak and electromagnetic forces. With such a rich history, it can only be hoped that the scientific legacy of Islam continues to grow.
Abubakar Abioye is a 3rd year medical student at Balliol College. Art by Emma Wilkins.
Hereditary Yet Infectious Canniblism, Incurable Insomnia, Mad Cows... and the Prion
A
t first sight, it would appear that the cannibalistic Fore Tribe of Eastern Papua New Guinea has little in common with a family from the outskirts of Venice. For the most part, this is indeed true, but curiously, both have fallen victim to deadly neurological diseases that have been traced to the same culprit. Until the 1970s, the Fore suffered from devastating epidemics of Kuru, a disease that causes the victim to shake and laugh spontaneously until death. In parallel, in the early 1970s, members of a Venetian family found that by middle age, they were unable to sleep, and died within a few months of exhaustion and dementia from what came to be known as fatal familial insomnia. Although the symptoms are different, both diseases are caused by the same rogue agent, an infectious protein called the prion. Prions create small holes in the brain, giving it a spongy appearance and thus earning them the name Transmissible Spongiform Encephalopathies (TSEs). TSEs caught the attention of Stanley Prusiner, a young American scientist who began researching scrapie—a form of TSE found in sheep—in 1972. It was first thought that TSEs were caused by a slow-acting virus, however Prusiner could not detect the presence of nucleic acids, the building blocks of viruses, in his scrapie preparations. Instead he found amino acids, the components of proteins.
Prusiner became convinced that TSEs were in fact caused by a protein, which he named the prion, and published his findings in 1982. This caused a furore in the scientific community, sometimes attracting vicious attacks. The concept of an infectious protein was seen as scientific heresy at the time. In the following years, with no viral cause to be found, and an accumulation of research findings supporting the concept of an infectious prion protein, the scientific community slowly began to accept prions as the cause of TSEs. Prusiner’s research would prove to be particularly relevant in light of the bovine spongiform encephalitis (BSE, or more commonly, mad-cow disease) epidemic of the late 1980s and 1990s. In 1997, Prusiner was awarded the Nobel Prize in Physiology or Medicine for his discovery. Surprisingly prion diseases, unlike bacteria or viruses, can be both contracted bby infection and inherited. It is understood that Kuru must have originated spontaneously from one individual around the 1800s, whose infectious brain was eaten upon his death during cannibalistic funeral rites. When the mode of transmission was uncovered, cannibal practices were halted, and Kuru is now almost non-existent. Fatal familial insomnia, on the other hand, is a rare yet dominant inherited genetic disease that first emerged in the Venetian family, whose members, unfortunately, still suffer from it. Like all prion diseases, Kuru and fatal familial insomnia are incurable. 9
Another surprising feature of the prion protein is that it is found in healthy individuals at the surface of certain types of cells. The healthy, non-infectious form of the protein is easily soluble, can be digested by enzymes, and is folded into coiled ribbon-shaped structures named alpha helices. Its normal function is yet to be determined, though research suggests it may have a function in long-term memory. In its abnormal and infectious form, the protein has the same composition, yet is insoluble, resistant to enzyme digestion, and is folded into pleated structures called beta sheets. When the infectious prion protein comes into contact with the normal form, it causes it to misfold into beta sheets, thereby converting it into the infectious form. The abnormal form is also heritable, originating from a mutated gene, and which can be passed from generation to generation.
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Despite Prusiner’s Nobel Prize, many still doubted the existence of an infectious protein.
Despite Prusiner’s Nobel Prize, many still doubted the existence of an infectious protein. Sceptics argued that unless infectious material could be generated in-vitro (that is, in the laboratory, outside of the human body) from defined components, the prion hypothesis would remain unconvincing. Over the last three years, this has finally been achieved, demonstrating that the prion is indeed the active component of TSEs. However, many questions remain unanswered; the underlying mechanism of brain degeneration isn’t understood, and it is not possible to rule out the presence of other components involved in prion disease. It would seem that there is much more to learn about these perplexing proteins. Celia Bell is a Masters student in the Zoology Department. Art by Kate Pocklington.
Imaging in a Flash
Shining light on the new applications of X-ray photography
E
ver since Wilhelm Röntgen photographed the inside of his wife’s hand in 1896, the imaging power of X-rays has been providing us with sights hidden from the naked eye. Their penetrating power allows us to peer deep inside all manner of objects, with X-ray scanners now appearing in places as varied as airports, hospitals, and art galleries. However, the nanometre (one billionth of a metre) wavelength of X-rays also allows scientists to look at objects far too small to be seen with conventional microscopes. Through the development of X-ray crystallography in the early twentieth century, the atomic structure of crystals was revealed. As the technique matured, it allowed for the imaging of far more complicated structures such as DNA.
As the name suggests, crystallography requires crystals, where the repetition of atoms is key to the entire process. These atoms in a crystal scatter X-rays, which then form characteristic ‘diffraction patterns’. The regular lattice of the crystal reinforces the diffracted X-rays, strengthening the pattern, the details of which encode information about the structure and chemical composition of the crystal. To date, crystallography has imaged tens of thousands of crystalline protein structures, including important molecules such as insulin. Knowing the atomic arrangement of these tiny objects is crucial to understanding how they function, which is essential for developing new drugs and treatments.
Sadly not everything can be made into crystals, meaning that the exact form of many important biological entities remains elusive. Furthermore, the process of crystallisation can damage biological matter, in which case the images obtained are inaccurate representations of the molecules themselves. Now scientists are finding ways around these limitations using ultra-short bursts of X-rays to record diffraction patterns from single molecules. These techniques capture complete structures instantly without the need for crystals. However, without a crystalline structure, we no longer have a regular lattice to reinforce the diffraction. As a result, to image an individual molecule cleanly and with enough detail, an extremely high dose of X-rays is required. This dose is so high, in fact, that it quickly destroys the object under scrutiny. But, if the X-ray pulse is short enough, it can pass through before the molecule has time to explode, producing a clear diffraction pattern. Biological bodies explode within tens of femtoseconds (ten million billionths of a second). While short pulse X-ray sources have been around for some time, it was only at the beginning of this century that short enough pulses with sufficient intensity became available, with the advent of the X-ray free-electron laser. These enormous machines use large arrays of powerful magnets called undulators to wiggle pulses of electrons side-toside very rapidly. These oscillations cause the electrons to emit radiation with exceedingly high intensities in femtosecond bursts. The first realisation of ‘diffraction before destruction’ came in 2006, when images were recovered from a single 25-femtosecond freeelectron laser shot. The object—a nanometre-sized etching on a silicon nitride membrane—was placed into the X-ray beam, which passed through it so quickly that the image obtained showed no distortion 10
at all, even though the object was completely destroyed by the process. This remarkable achievement was followed a year later by snapshots (with femtosecond exposure times) of nanometre-scale silicon spheres exploding. In this experiment, X-rays pass through the sphere, initiating an explosion, and are reflected back by a mirror through the bursting ball, capturing its instantaneous structure. Between exposures, the reflecting mirror is moved by a tiny amount. Subsequently, the pulse takes longer to return to the sphere, which has now expanded a little more, allowing another step in the explosion to be recorded. The whole process is repeated many times, creating a series of images charting the detailed destruction of the ball.
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Biological bodies explode within tens of femtoseconds.
With these preliminary ‘proof-ofprinciple’ experiments complete, the stage is set for further exciting investigations into many biological and chemical substances, previously inaccessible using other imaging methods. Last ast year, the Chapman group from the University of Hamburg presented work which used this technique to image Photosystem I, an important protein for photosynthesis, in full 3D. These ‘snapshot’ techniques will monitor fundamental processes—such as protein folding—as they happen, producing high-resolution images on the timescale of biological activity. As these technologies become more sophisticated, the possibilities for understanding the microscopic world are growing larger than ever before. Nicky Dean has just completed a DPhil in Physics, using ultrashort laser sources to study electronic and structural dynamics in different materials. Art by Inez Januszczak.
Women Men are are from from Mars, Mars, Women Men are from Venus Why Why wewe should should all come all come back back down to Earth... to Earth...
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he idea that “Men are from Mars, Women are from Venus” is the premise of endless jokes and media articles. Most people are happy to accept that boys instinctively prefer cars and machinery while girls are attracted to prettier things. Men are comfortable with the idea that women are no good at parking and map reading, while women are equally convinced of their superior multitasking ability and emotional intelligence. Men and women are different, undoubtedly, and nobody disputes that gender specific brain circuitry exists to control our reproductive behaviours. To assume that anatomical differences between the brains of males and females also underlie differences in cognitive ability is, therefore, an easy step to make, and one that has enjoyed huge attention in the scientific literature throughout recent decades.
Some, including psychologist Dr Cordelia Fine and socio-medical scientist Professor Rebecca Jordon Young, have argued that studies to this end simply add a veneer of scientific
credibility to the essentially Victorian idea that the differing accomplishments of men and women are innate and hard wired. Such a view has since been dubbed “neurosexism.” While this may appear to be a feminist exaggeration, recent work suggests that structural differences between male and female brains may not be significant enough to back up popular convictions about ‘unalterable’ differences in their capabilities. It is likely that nurture wins out over nature when it comes to personality differences between males and females; that these are cultural dichotomies rather than neural dichotomies.
been challenged. In 2003, Dr John S. Allen of the University of Iowa published a paper in the journal NeuroImage which stated that the differences between the sexes is in fact much lower for the corpus callosum than for other parts of the brain.
What exactly are the differences between the male and female brain that have caused such controversy? Allowing for overall differences in body size, men have been shown to have bigger brains than women by about five percent. This is because the male brain contains a greater amount of white matter projecting from more numerous and densely packed neurons (nerve cells). Women on the other hand seem to have a more highly developed neuropil—the space between cell bodies that allows for communication among neurons. As a result, it has been assumed that the female brain is comparatively better at ‘interhemispheric’ or ‘long range’ communication. The female brain has also been reported to contain a proportionally larger corpus callosum—a bundle of neurons that serves as a communication link between the left and right sides of our brains, although this finding has
Two areas in the frontal and temporal lobes related to language have been demonstrated to be larger in women than in men, providing some biological evidence for their apparent linguistic superiority. The IPL (Inferior Parietal Lobe) is significantly larger in men than in women, particularly on the left side of the brain. This area is associated with mathematical ability, and was especially well developed in the brain of Albert Einstein. Women meanwhile possess a significantly larger OAR (Orbitofrontal to Amygdale Ratio). Put simply, this implies that women are more capable of controlling their emotional reactions. In addition, women may also have a larger limbic system, also known as the ‘emotional brain’ than men, putting them, to use a hackneyed expression, ‘more in touch with their emotions.’
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In speakers of Mandarin Chinese, both sides of the brain are used in language processing, regardless of gender.
Why might these differences exist? Some, for example Professor David Geary at the University of Missouri, have attributed them to evolution, invoking a standard caveman argument. Apparently a man’s superior map reading ability may be down to the fact that this was required for him to become a better hunter, while the women stayed at home working on their linguistic prowess—
switching on ‘the allure’ was more users of an ideographic or pictographic wired’ than ‘hard wired’, and highly of a priority as far as they were written language. Professor Sophie susceptible to cultural moulding. As a concerned. Others argue that Why Scott weand should colleagues all come at the back Wellcome to Earth... result of this plasticity, or changeable hormones may be a more important Trust carried out research in 2003 function, Fine argues that it is wrong factor. During development in the demonstrating that this was the case in to interpret any differences between womb, hormones and other chemical speakers of Mandarin Chinese. Both the sexes found in brain imaging substances can enter a foetus via the sides of the brain are used in language as evidence of an innate disparity. mother. Increased exposure processing, regardless Furthermore, many studies of this kind to male hormones may of gender. While base their conclusions on woefully lead to the formation no assumptions small sample sizes, a common flaw in of a ‘male’ brain. are made that much of the empirical research. Parietal Lobe Support for the contrast Frontal this hypothesis, is the result Professor Robert Winston has agreed Lobe however, is of a racial with the hypothesis that females varied, with foetal difference, it who share a uterus with males (nonOccipital at least serves testosterone identical twins) may be significantly Lobe being linked to to show that masculinised as a result of exposure Temporal Lobe some, but not all, isolated to testosterone. Anybody who knows Cerebellum aspects of cognition research of any female with a male twin is likely and behaviour. projects to regard them as sufficiently feminine are not universally as to rubbish such an idea outright. Gina Rippon, professor of cognitive applicable in the great gender Yet gender differences in the behaviour neuroimaging at Aston University, debate. of small children have nevertheless argued last year on the BBC’s Today been highlighted to emphasize that programme that research into neural Simon Baron Cohen, professor of males and females are born differently, sex differences has often been developmental neuropathology independent of any culturally enforced misleading, and she’s not alone in at Cambridge University, is often changes. However, the fact that her opinion. A spate of books and targeted as a sexist children show Left Hemisphere these gender Right Hemisphere articles now provide a much needed proponent of the critique of the empirical evidence for idea that men and differences the existence of hard wired differences women are wired is somewhat between the brains of men and women, up differently. He inevitable. debunking the ‘pseudo science of suggests that From the neurosexism'. Professor Rippon males are more outset it emphasises that the similarities likely to have is virtually between male and female brains an ‘S type’ or impossible to are far more overwhelming than their systemising type raise a child in differences. Rippon and her team brain, while women a gender neutral are experts in using state of the art are more likely to be environment— techniques to produce illuminated great empathisers with take the use of cross sections of the brain, allowing ‘E type’ brains. His belief blue and pink them to analyse realtime responses to that “essential” differences exist Corpus Callosum blankets as an various environmental stimuli. By such between the brains of men and example. Furthermore, methods, she and her team declare women has been challenged by Dr discrepancies in the mechanical and that they have found no significant Cordeila Fine, author of Delusions spatial abilities of boys and girls can be differences between male and of Gender, who has raised questions almost completely erased by practicing female cognition. Consequently, she about his methodology. Baron mechanical tasks, supporting Fine's questions the functional significance Cohen’s finding that newborn boys views. of anatomical differences between prefer to look at pictures of mobile male and female brains. phones, while newborn girls prefer It seems that the idea that the brains to look at pictures of faces may of men and women have been Females who share have been skewed by failings in his constructed differently by hormones a uterus with males methodology to erase inadvertent cues and evolution is becoming old (non-identical twins) given to the subjects by experimenters. fashioned, and the view that our plastic may be significantly brains are moulded more by societal masculinised. Dr Fine argues that neurological forces is gaining momentum. Perhaps differences between men and we're all from the same planet after all. Interestingly, the fact than men process women are not only minimal, but language with only the left side of their also changeable. This opinion is well Eleanor Dennis is a third year Biology brain, rather than with both sides as founded—one of the defining features undergraduate at Wadham College. women do, has been found not to of the human brain is its plasticity. Art by Matthew Jones. be the case in oriental populations— Our brains are likely to be more ‘soft
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Westgate Centre In the thirteenth century, the site of the Westgate Centre was occupied by a Franciscan friary. One of the friars, Roger Bacon, was a philosopher who also carried out investigations into optics, alchemy and astronomy. His many accomplishments, including the invention of the magnifying glass and the definitions of reflection and refraction, earned him the name ‘Doctor Mirabilis’ or the wonderful doctor.
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Oxford: City
hroughout history, Oxford has been at the heart of sc city itself has many historic sites that bear witness t guided tour through the ages where the buildings co
Christ Church College Christ Church College was the host of the first Anatomy School of Oxford University. Now known as the ‘Lee Building’, and part of the Christ Church SCR, the school was built in 1766-7 on the money provided by Dr Matthew Lee’s will. Matthew Lee himself studied at Christ Church and went on to carve a career as a royal physician. The Anatomy School or ‘Skeleton Corner’ of the College had a lecture room with a gallery, as well as a basement used for dissections.
Museum of the History of Science The Museum, also known as the ‘Old Ashmolean’, was completed in 1683 and was the world’s first purpose-built public museum. It was originally used to house the collections of Elias Ashmole as well as serving for the pursuit of ‘natural knowledge’. The newly established School of Natural History lectures took place on the ground floor of the museum and the basement was used as an alchemical laboratory.
University College On the wall of University College is a plaque marking the site of the former laboratory of Robert Boyle and his assistant Robert Hooke. Here, between 1655 and 1668, their work led to the formulation of Boyle’s Law and the design of an air pump for studies of vacuum, respiration and combustion. Robert Hooke was a chorister at Christ Church and is remembered for his definition of Hooke’s Law and the publication of ‘Micrographia’, detailing his use of a microscope to first recognise and describe cells. Botanic Gardens
The University Botanic Garden is the oldest in Britain! Founded on the donations of Sir Henry Danvers in 1621, it was created to grow medicinal plants for “the glorification of God and for the furtherance of learning”. The oldest tree is a yew planted by the Garden’s first Curator, Jacob Bobart, in 1650. It is very fitting that today yew trees are used as a source of taxotere, a well-established drug in cancer treatment. Maria Demidova is a 4th year DPhil student in the Departm in cell division. Art by Maria Demidova. 13
y of Science
Wadham College
The Royal Society, England’s leading scientific institution, has its roots firmly intertwined with Wadham College. cholarship and at the forefront of scientific discovery. The When appointed Warden of Wadham in 1648, John Willis’ interest to the blossoming of modern science. Take this magical in ‘experimental philosophy’ had drawn many of Oxford’s great ome alive to tell us fascinating stories from the past! minds, including Robert Hooke, Christopher Wren, Seth Ward and Robert Wood, into ‘The Oxford Experimental Philosophy Club’ which played a key role in the foundations of the Royal Society in 1660. The Wadham garden bore witness to a range of mechanical devices and scientific instruments as well as a ‘talking statue’!
ment of Biochemistry studying chromosome segregation
Natural History Museum Construction of the museum was initiated in 1855 by Regius Professor of Medicine, Sir Henry Acland to unite the teaching and research facilities of natural sciences. The Museum is home to many natural history collections including those from the Old Ashmolean Museum, and geologist William Buckland. In June 1860, the newly opened Museum hosted the famous, furious debate between Thomas Huxley (Darwin’s ‘bull-dog’) and the Bishop of Oxford, Samuel Wilberforce, over Darwin’s theory of evolution by natural selection. Modern Science Area In World War II, science departments made major contributions to Allied technologies. When not busy ‘Digging for Victory’ or creating air raid shelters, a major research direction was finding antidotes to mustard gas and lewisite, a compound used in chemical weapons. Investigations by Rudolf Peters, Robert Thomas and Lloyd Stocken led to the discovery of British Anti-Lewisite (BAL). Today BAL is used to treat heavy metal poisoning and other medical conditions. Dunn School of Pathology The face of medicine was changed completely with the advent of antibiotics, which were initially developed in Oxford. In the footsteps of Alexander Fleming’s finding that a Penicillium mould kills bacteria, Howard Florey, Ernst Chain and Norman Heatley lead a team to purify and test penicillin in the 1930’s. The mould was initially grown in hospital bedpans borrowed from the Radcliffe Infirmary and trialled on a local policeman! Florey, Chain and Fleming were awarded the 1945 Nobel Prize for Physiology or Medicine. Radcliffe Observatory The strikingly beautiful Radcliffe Observatory forms the centrepiece of Green Templeton College. Thomas Hornsby, the Savilian Professor of Astronomy, suggested the Observatory after watching the transit of Venus in 1769 in the nearby Radcliffe Infirmary. The Observatory building was equipped with the finest scientific instruments for astronomical and meteorological observations from 1773 until 1934.
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Micromachines
How future technology may be built on microbes
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olluted water, damaged buildings and a dependency on fossil fuels are all big problems which are encountered by mankind daily. However, three unique solutions that use some of the smallest organisms on the planet showcase the remarkable power of microbial biotechnology. Bacterial Bacterial builders Builders Buildings are one step closer to being alive, thanks to a research team led by Dr Henk Jonkers at Delft University of Technology in the Netherlands. The team has created “bioconcrete”—a special mixture of concrete that contains dormant bacteria and their food source, which contains urea. When cracks appear in the concrete and water seeps in, the bacteria ‘wake up’ and metabolise the urea. Carbonate ions are formed as a waste product, which react with calcium ions already present in the concrete. The resulting calcium carbonate then fills in the cracks, allowing the buildings to effectively repair themselves. This process is made possible by carefully selected bacteria. These bacteria live in soda lakes—among the only natural environments that have the same alkalinity as concrete. Moreover, the bacteria may remain dormant for up to 200 years, so the healing properties of the concrete will be present throughout a building’s lifetime.
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Bacteria may remain dormant for up to 200 years.
Although bio-concrete is more expensive than traditional concrete, there will still be vast economic savings. Concrete is the most widely used construction material on earth and repairing it can be extremely costly, especially in hard to reach areas such as underwater tunnels.
From Pollutants to Protozoa
Algae Power
At Woods Hole Oceanographic Institute, Massachusetts, marine biologist Dr Scott Gallager has developed an ingenious method of detecting toxicants in drinking water by analysing how protozoa swim. Protozoa are organisms made up of just a single cell. This cell is covered in tiny hair-like protrusions, called cilia, which act like oars to enable the cell to move. Toxicants including pesticides and biological warfare agents affect the protozoa’s metabolism and cilia, which in turn alters their swimming.
The hunt for fuel usually begins with behemothic oil rigs tearing into the earth’s crust, but future fuels could come from humble microscopic algae. Companies such as Sapphire Energy in the USA, are preparing to scale up production of ‘Green Crude Oil’. They have managed to create strains of algae that produce oil molecularly similar to thin crude oil. This green oil can be immediately refined into alternatives to conventional petroleum-based transport fuels. Since the algae metabolise carbon dioxide from the atmosphere to produce the fuel in the first place, there are far less overall carbon dioxide emissions, but the advantages don’t stop there.
To detect toxic components, rotozoa are placed in a sample of water, and observed using a digital camera and specially designed software. The protozoans’ swimming motion is compared to that in an uncontaminated sample. The apparatus is selfcontained in a device called a Swimming Behavioural Spectrophotometer (SBS). From a single test, it’s possible to determine whether or not water is safe to drink. The biologically based SBS can substantially save both time and money. Traditional chemical methods can take between 1 and 3 days to return results and cost up to $250. The SBS device provides almost instantaneous results for as little as $1 a test. Furthermore, the protozoans only need replacing every two months. The project has received crucial commercial support from Petrel Biosensors who are helping to streamline the SBS so that it can be used as a handheld unit. United Nations statistics state there are currently 880 million people worldwide without access to clean water, meaning the impact of the device could be tremendous. 15
Ethanol is currently the bio-fuel of choice, but this is obtained by harvesting and fermenting maize, increasing the price of this food crop on the global market, making it unaffordable to those who need it most. Using algae instead allows the demand for fuel to be met without adversely affecting food security. The production plants would not even need to be on agricultural land—all that is needed is sunlight and carbon dioxide. The algae are grown in tanks that could be placed in relatively barren land, such as deserts. Scaling up these technologies is looking increasingly promising. In September 2010, a crucial bill was passed in America that gives much needed financial incentives to algaebased renewable fuel. With this support, global adoption of algal biofuels is looking to be more and more hopeful. Ian Polding is a 2nd year undergraduate in Biology at Somerville college.. Art by Samuel Pilgrim.
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Out of This World
Delving into the depths of the cosmos, and finding more than we expected
We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time.” — T. S. Eliot
of known exoplanets to over 500, what makes this particular discovery so special? Well, this is the first exoplanet discovered which is believed to have originated outside of our own galaxy, the Milky Way.
n the mind of the great Greek philosopher Ptolemy, the world was ordered and simple: a series of concentric circles representing the paths of the celestial objects known at the time, with a clear distinction between the ‘here’ (humankind on Earth at the centre of it all) and the ‘there’ (the starry skies outwards).
The planet was found in the Helmi stream, a large collection of stars that stretch across the Milky Way. Research led by Dr Amina Helmi, also at the Max Planck Institute, that was published in the journal Nature in 1999, concluded that the Helmi stream, was once part of a dwarf galaxy, and was consumed by the much larger Milky Way some six to nine billion years ago, giving HIP 13044b an extragalactic origin.
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But in the early 1600’s, Galileo, using the newly invented telescope, observed Saturn, the moons of Jupiter and the phases of Venus. This provided empirical evidence for Copernicus’ then controversial heliocentric (suncentred) model of the Solar System. Since then, leaps in technology have led to the detection of previously unknown and unimagined cosmic bodies such as black holes and pulsars, with new discoveries continuing to be made even now. On the 18th November 2010, a group led by Dr Johny Setiawan, from the Max Planck Institute in Germany, announced the discovery of a new exoplanet—a planet outside our Solar System. The planet is a gas giant and is known as HIP 13044b. It is thought to have about 1.25 times the mass of Jupiter and orbits its host star (HIP 13044) 2000 light years away from Earth. Astronomers detected the planet by looking out for periodic ‘wobbles’ of the host star that are caused by the gravitational effect of a massive planet orbiting close by. With HIP 13044b bringing the number
re-examine the current models, and to consider alternative ways in which planets may be created. Additionally, the star has aged past the red giant stage and the planet is orbiting extremely close to it, indicating that it may have been pulled inwards from a wider orbit as the star evolved. HIP 13044b is doomed to be swallowed up when the star swells again in the next phase of its evolution.
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Astronomers detected the planet by looking out for periodic ‘wobbles’ of the host star.
As well as taking research beyond the boundaries of our galaxy, the finding could be useful in analysing the future of our own planetary system, and in understanding what could happen when the Sun develops into a red giant in about 5 billion years.
That’s not the only peculiar thing. A star’s chemical composition is thought to be a major indicator of its probability for hosting a planet. Most known exoplanets orbit stars that are rich in heavy elements and that are at least as metallic as our Sun. This is because the currently accepted theory of planetary formation predicts that a higher metal content leads to faster formation of planetesimals, fragments of matter that come together under the force of gravity to create new planets. However, HIP 13044 has only about one percent the metallicity of the Sun, making it the most metal-deficient star known to have an orbiting planet. These new findings are puzzling scientists who have been forced to 16
As the first evidence of an extragalactic planet, this discovery increases the probability that planets are as prevalent outside of the Milky Way as within it, which inevitably raises the question of how many of these planets might harbour life (see ‘Bang!’ Trinity 2010: ‘Intelligent Life: Apply Elsewhere’). The search for new exoplanets has come a long way since their first discovery in 1995. Since 2007 the number of known exoplanets has more than doubled, providing us with new data and developing our understanding of our place in the cosmos. Certainly this is one of the most exciting fields of research in astronomy at the moment and with humans delving deeper into the cosmic unknown, who knows what undiscovered worlds await us? Sara Lukic is a 1st year undergraduate at St Catherine’s College reading Physics. Art by Kate Pocklington.
Women are from A State Mars, of Collapse Men are from Venus Teasing apart Why the we knotty should problem all come ofback quantum to Earth... measurements
Q
uantum mechanics is a branch of physics which describes the behaviour of matter at the atomic and sub-atomic level. In the quantum world, matter behaves in a completely differently manner to the objects we see around us. A striking feature is that quantum systems can exist in more than one state simultaneously; in the macroscopic world, this is like saying a radio can be on and off at the same time.. This contradicts our everyday experiences, leading to some very interesting consequences which cannot be fully explained by our current quantum theories.
Two famous experiments illustrate some of the unusual characteristics of the quantum world. The first is the double slit experiment, originally performed by Thomas Young in the early 19th century. It demonstrates the dual nature of matter—the fact that matter sometimes behaves like a collection of particles, and sometimes behaves as a wave. The experiment involves firing a single beam of electrons at two slits with a photographic plate beyond. Electrons have mass and momentum, which are properties of particles, so we might expect them to exhibit particlelike behaviour by producing a fairly even pattern over the whole of the photographic plate: imagine throwing tennis balls at a wall through two holes. But instead we observe a series of light and dark bands, much like the pattern seen when two pebbles are dropped into a pool of water and the resulting waves interact. This suggests the electrons are behaving like waves; each slit acts as a single wave source, and the wave’s peaks and troughs interfere constructively (combine) or destructively (cancel out) to produce a series of light and dark fringes. Mathematically, these waves are treated as combinations of various different possible states of the electrons, each characterised by a construction called a ‘wave function’. To describe the nature of matter fully all of these wave functions must be gathered together, undergoing what is called ‘superposition’. It’s this process
of combining wave functions which allows interference to occur. So far, quantum theory can cope. But there’s more. Our second experiment is affectionately entitled Schrödinger’s Cat. It should be stressed at this point that this is a thought experiment, and no cats have actually been mistreated by quantum physicists! It involves a cat, sealed in a box, with only a Geiger counter, a bottle of cyanide and an atom of a radioactive material for company. The half-life of the radioactive material is sixty minutes, which means that after one hour there is a fifty-fifty chance that the atom has radioactively decayed. The system is rigged so that if the Geiger counter detects the atom decaying, the cyanide bottle is smashed and the cat dies. So after one hour, what has happened to the cat? The mathematics of quantum mechanics would have it that the poor animal is in a superposition of states— it is in some way both dead and alive as both outcomes are equally likely. But this just doesn’t make sense. After all, when we open up the box to check, we will definitely see either a living cat, or a dead cat—a single result. It seems that at some stage, the superposition of states must be reduced to a single state which decides the fate of the cat a process referred to as the collapse of the wave function. Various ways of understanding the collapse have been proposed and some of these hypotheses throw up more questions than answers.
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Decoherence An important result of quantum mechanics is decoherence theory. This reminds us that when we carry out a measurement on a system which is in a superposition of states, the system is not isolated: the states all interact separately with the environment, so that the environment itself becomes part of the superposition. Imagine you are looking at a rainbow— you will see the end of the rainbow hovering over a particular spot. However your friend on the other side of town will see the end of the same rainbow above a different location. In other words, where you stand dramatically affects what you see. Since we, as observers, are now included in the system, our experiments will give determinate results as if the wave function has collapsed to a single state i.e. the end of the rainbow appears to be in one place as a direct result of our observation although there are many spots it could be in. However, decoherence only produces the appearance of wave function collapse, not a real collapse- there are still many possible ends to the rainbow, we just don’t have any way to observe this superposition. Thus decoherence helps with the mathematics, but as an interpretation of what is really going on it remains incomplete.
Copenhagen Interpretation
Many-Worlds Interpretation
Consciousness
The oldest way of understanding quantum mechanics is called the ‘Copenhagen Interpretation’, This approach, developed in part by Danish physicist Niels Bohr in the early history of quantum mechanics, involves using the theory to make predictions, but reserving judgement as to the deeper meaning of the mathematics. That means ignoring the idea of Schrödinger’s cat being dead or not, and satisfy ourselves that there are two possible outcomes to the experiment with certain probabilities.
Despite the name, this interpretation doesn’t really postulate distinct worlds separate from ours in space and time. In fact, this is perhaps the simplest interpretation: it merely claims that there is no wavefunction collapse at all. When a measurement is made, rather than multiple states collapsing to one, the observer comes to exist in multiple states. This is not obvious to us as we are only ever aware of being in one of these states, but simultaneously, other versions of us are in other states and are aware of those states instead. Schrödinger’s poor cat is indeed both alive and dead—the reason we only ever observe it one way or the other is that one version of us observes the living cat while a different version of us observes the dead one.
One suggestion is that the wave function collapse is caused by consciousness: macroscopic systems can indeed be in several states at once, but as soon as a conscious observer makes a measurement of the system, the wave function collapses as part of this interaction. This theory would claim that Schrödinger’s cat can indeed be both dead and alive, but only until we open the box. Once we check to see the state of the cat, the wave function collapses, and the cat is once again in a single determinate state.
Though it’s easy to dismiss this as an attempt to sidestep the really hard questions in quantum mechanics, proponents of the Copenhagen Interpretation have sound philosophical reasons for their position. After all, we cannot be sure that there is any deeper reality underlying quantum mechanics—and even if we could, we would have no real reason to think that it resembles our everyday experience to such a degree that it is necessary for us to have any conceptual grasp of it. The likelihood of deciding conclusively on a correct interpretation of quantum mechanics any time soon appears small. Many scientists are content to use the theory as a predictive tool
without trying to understand what it really means, but for those who dislike this approach, there are a multitude of theories aiming to account for the strange behaviour of quantum physics. Physics alone cannot decide between the interpretations: ultimately this is an area where individuals must come to their own conclusion, guided as much by philosophical principles as by physical facts.
This hypothesis seems rather implausible. It is hard to believe that there are multiple versions of the same person existing and having different experiences in different branches of the world. It is nonetheless gaining popularity, mainly because it doesn’t require us to postulate wave-function collapse as an additional feature of the theory. However, all the other methods of introducing the collapse appear rather artificial, which gives us reason to think that perhaps no such thing really occurs.
The main problem with this view is that there is little evidence to suggest that consciousness plays any special role in quantum theory. Rather, it shows that there’s something distinctive about the measurement process—we have no reason to think that it is specifically consciousness that plays the pivotal role.
Emily Adlam is a second year student reading physics and philosophy. Art by Maria Demidova. 18
Literary Matter
Bedside reading for the intellectually curious. Why does E=mc2? (And why should we care?), Brian Cox and Jeff Forshaw
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hanks to the recent success of his BBC television series, ‘Wonders of the Solar System’, Professor Brian Cox is well on his way to becoming a household name. With his ‘rock-star’ past (literally) and vibrant enthusiasm on-screen, the young physicist (well, he’s 42) has become the new face of popular science, proof that not all scientists are bearded old men with a penchant for
The Earth After Us, Dr Jan Zalasiewicz
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ne hundred million years from now, aliens arrive on Earth. There will be no greeting for them though; humans have long been extinct. Instead, the alien race is at liberty to explore our planet, and especially its geological record, to discover its 4.7 billion year history.
So begins ‘The Earth After Us’, by Dr Jan Zalasiewicz. In this fascinating book, Zalasiewicz, Lecturer in Geology at the University of Leicester, takes the reader far into the future to look at the geological record of plate tectonics, climate change, mass extinctions and, critically, traces left by the human race. Cities, cars, tunnels, iron and plastic, all will be condensed into a thin layer of rock, which will also show signs of dramatic climate change and strange movement of wildlife around the planet.
tweed and chalk dust. It was with high expectations then, that I picked up ‘Why does E=mc2? (And why should we care?)’. A joint effort between Cox and fellow Manchester University professor, Jeff Forshaw, the book aims to explain how Einstein’s infamous equation comes about and what significance it has.
not to compare popular science like this to the thick reference tomes academic physicists are accustomed to. Textbooks are an efficient but brutal means of imparting knowledge, whereas books like this one serve to make science accessible to the masses—a purpose that ‘Why does E=mc2?’ manages to fulfil, eventually.
Unfortunately although the authors do achieve this, whilst keeping their promise to use mathematics no more complex than Pythagoras’ theorem, their methods of simplification sometimes backfire. They often labour the point, and technical concepts can become hidden in a tangle of digressions instead of being explained clearly. A determined reader with a sharp machete will make it through to the crux of a mathematical argument, but a casual one is likely to quickly find themselves lost in a quagmire of metaphors. Of course, it is important
Communicating scientific ideas to a non-technical audience is not an easy task, but when they are not stumbling through the derivation of Einstein’s equation, Cox and Forshaw manage to do a fine job of it, weaving neatly in and out of relativity, particle physics and astrophysics. All in all, as an attempt to answer the question in its title, it is messy, to say the least. But as an attempt to communicate the awe and fascination with which the authors view the universe, it is a success.
explore how geologists and palaeontologists reconstruct the past history of our world, offering an accessible and interesting insight into how the planet has evolved over time. The rapid changes to the climate and environment, instigated by comparatively short lived civilisations of humans, are in stark contrast to the planetary norm. Thus the book contains a moral warning as well as scientific information: that our activities have already left an irreversible footprint on our world, and it is not a particularly good one.
Samuel Pilgrim is a second year Physics undergraduate at Wadham College. Art by Inez Januszczak. Zalasiewicz writes entertainingly and simply, without being patronising. The topics covered in the book give an excellent summary of the geological scientific process, as well as leaving the reader with considerable food for thought.
Leila Battison is a 3rd year DPhil student in Palaeontology and Astrobiology at Worcester College.
Win a copy of The Earth After Us! All you need to do is excavate your imagination, and create for us an amazing work of art on the theme: ‘The Earth After Us’. Your artwork can be drawn or painted, on paper or on screen and the winning artwork will be featured in the next issue of Bang!. Send your entries to bangscience@googlemail.com by Friday 8th week for your chance to win. Good luck!
This relatively short book uses the perspective of the alien visitor to 19
Nature’s Palette
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Harnessing the colours of creation for a brighter future
A red sun rises. Blood has been spilt this night
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he ominous words of the elf Legolas in Tolkien’s ‘The Two Towers’ conjures up a vivid scene in the mind, one which would lose much of its evocative nature if our blood was actually green, or yellow, or baby blue. Likewise a faint mauve environment would no doubt have provoked quite different poetical musings from the likes of Cowper and Keats, than the verdant one in which we live. The palette with which nature was painted is a clever chemical one. Plants are able to convert carbon dioxide and water to sugars during photosynthesis at an unimaginable rate because they contain the green dye chlorophyll. What’s more, haem—part of the molecule haemoglobin—has a structure which is perfectly designed to transport oxygen in the body to where it is needed most. It is this haem unit which is responsible for the redness of blood. White light, emitted by the sun, is made up of many colours (as you can see if you allow light to pass through a prism, or indeed raindrops to create rainbows). Pigments and dyes are coloured because they absorb some of this light, but not all of it. The rest is reflected as the colour we see. Haem and chlorophyll are close cousins based on a family of ring shaped molecules called porphyrins. Indeed the word porphyrin comes from the Greek word ‘porphyra’ meaning purple pigment. Porphyrins are brightly coloured compounds made up of carbon and nitrogen
atoms arranged in a fairly rigid ring, often with a metal ion bound in the hole in the middle (such as iron in the case of haem). Lots of electrons whizz around the ring like cars on
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The palette with which nature was painted is a clever chemical one.
a Scalextric track. These electrons interact with light to gain energy, absorbing only the colours of light which match to the energy they need. Many subtle factors may affect the exact colours absorbed, for example the binding of oxygen to haem turns the molecule bright red, as you can see if you compare the colour of blood in your veins (scarlet) to that of your arteries (dark red-brown). Faulty production of haemoglobin causes the disorder porphyria which can cause horrific symptoms including sensitivity to sunlight, skin darkening and even increased hair growthleading many to believe that porphyria is behind ancient tales of vampires and werewolves. Nature has chosen her dyes well and this is something mankind is keen to exploit. Porphyrins can be synthesised in the lab and hence harnessed as potential candidates for artificial light harvesting compounds. Just as plants use chlorophyll to fix the sun’s energy as the chemical fuel glucose, so chemists are developing similar compounds to turn the sun’s rays into electrical energy. In this new solar technology, a porphyrin is attached to a surface and exposed to light. This molecule absorbs the light and, in doing so, throws one of its electrons out from its 20
ring. The electron enters the surface material and flows through a circuit before eventually recombining with the porphyrin, generating an electrical current in the process. These new devices are called dye sensitised solar cells (DSSC). By chemically altering the outside of the porphyrin ring, this process can be made more efficient, offering cheap, accessible alternatives to the expensive solar cells currently in use. The properties of porphyrins have also been exploited medically, and are being used in cancer therapy trials as part of ‘photodynamic therapy’- using light to heal the body. A big problem in cancer therapy is how to specifically target and kill cancer cells without harming healthy tissue. Porphyrins can achieve this by passing the energy they gained from absorbing light to oxygen. Oxygen is very good at accepting this energy, and in doing
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Porphyria may be behind ancient tales of vampires and werewolves.
so, the oxygen becomes toxic to cells. Modification of the porphyrin molecule, by attaching water soluble regions, may allow it to be introduced into the body and taken up by cells. Specific cells may be killed by shining light through the skin onto the target area to generate the toxic oxygen. The areas left dark are not harmed because the porphyrin dye itself is not toxic. Porphyrins are not just bright and beautiful, but are prime examples of how nature, with its love of method and efficiency, has given us inspirational tools towards forging a cleaner, healthier future for ourselves. Nicola Davis is a 3rd year DPhil in Chemistry working on the synthesis and properties of porphyrin systems at Worcester College. Art by Kate Pocklington.
Women are from Age Before Mars, Men Beauty are from Venus Why we Can should we really all come live to back 1000? to Earth...
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t is said that there are only two things in life that are certain: taxes and death. With the recent increase in VAT it is difficult to dispute the former, but what are the prospects of putting off death? Ageing is the greatest cause of morbidity (illness) and mortality (death) in the world, so why isn’t more being done to combat it? Surely, the deaths of 100,000 people a day—equivalent to two-thirds of the population of Oxford—are worth paying attention to.
a leading biomedical gerontologist Human Aging, in Annals of the New (aging specialist), has received public York Academy of Sciences, de Grey attention as well as widespread elaborates on his contentious claim. criticism from the scientific community SENS— Strategies for Engineered for his declaration that “the first person Negligible Senescence—are “an to live to the age of 1000 is alive integrated set of medical techniques today”. Although designed to his optimism has restore youthful elicited scepticism There are 150,000 molecular and and controversy, it deaths a day globally. cellular structure has also fuelled 100,000 of these to aged tissues academic interest are age related. and organs”. This in the field of ‘maintenance The prevailing opinion is that ageing is biogerontology strategy’ differs inevitable and unavoidable; however, (the study of the ageing process).. from current methods, as it aims to there are a growing number of reverse the damage that occurs due academics who are challenging this In his 2002 paper Time to Talk to metabolism rather than prevent it uninviting fate. Dr Aubrey de Grey, SENS: Critiquing the Immutability of (gerontology) or prevent the process by which the damage leads to pathology or cell death (geriatrics). On the SENS website (www.sens.org), The Seven Reasons for Aging de Grey cites many papers that are Age Related Treatment believed to demonstrate the building Damage blocks of this anti-ageing procedure. 1. Cell loss/Atrophy Stem cells, exercise and growth factors Indeed one such paper by L. Regan 2. Senescent/toxic Ablate cells that are unwanted and co-workers in Proceedings of the cells National Academy of Science of the USA (PNAS) in 2000 explores the 3. Nuclear mutations/ Prevent lengthening of telomeres application of molecules which can epimutations (that break cross-links between cells to cause cancer) reduce the stiffness of heart tissue— 4. Mitochondrial Allotopic expression (expression of so-called AGE-breaking molecules. mutations
mitochondreal gene products from the nuclear genome) of 13 proteins
5. Extracellular cross-links
AGE-breaking molecules*
6. Extracellular aggreagates
Immune-mediated phagocytosis
7. Lysosomal aggregates
Transgenic microbial hydrolases
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A healthier, more able, older generation that would not retire at 65 and be bed-bound 5 years later.
De Grey believes he has identified seven all-encompassing biological causes of ageing (senescence), which have been put together to structure SENS (see table). SENS not only focuses on longevity—keeping the Grim Reaper at bay—but also provides a framework for eliminating many of the common afflictions that plague the population as they age. The proposition that you and I might live to the ripe old age of 1000 is explained by a concept termed by de Grey as ‘Longevity Escape Velocity’ (LEV). LEV suggests that in
*Advanced glycation end‐products ‐ molecules resulting from a non‐enzymatic reaction between proteins and sugar residues (Maillard reaction).
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Age related deaths make up 90% of the deaths in the USA. the next 30 years or so, the progress in regenerative medicine will allow us to live for another 30 years, and in those intervening years technology will gradually progress so that we can live for a further 30 years, and so on. The technology necessary to begin this chain reaction is available, but more active research into the subject is essential and, accordingly, more funding is needed to support progress in this field. The ageing population is currently seen as a burden on society and something to be feared. In general the view is that the longer a person is able to live, the longer they spend in retirement, and the more dependent they become on the younger working population for support. What de Grey predicts is a
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The prospect of significantly extending life is tantalising and seems to be within the realms of possibility...
healthier, more able, older generation that would not retire at 65 and be bedbound 5 years later. To cope with the changing dependency ratio, it is likely that the retirement age will increase.
The prospect of significantly extending life is tantalising and seems to be within the realms of possibility during our lifetimes. The MIT Technology Review offered a prize of $20,000 to anyone who was able to prove that SENS was “so wrong that it was unworthy of learned debate”. There were no successful entrants, though the main criticism of SENS was the lack of technology currently capable of accomplishing its end goals. So watch this space—SENS could yet pave the way to a utopian, long lived, illness free, future! Abubakar Abioye is a third year medical student at Balliol currently doing an FHS in neuroscience. Art by Emma Wilkins and Elizaveta Gelfrekh. 22
Bang! talks to . . . Simon Singh Science, media and monkeys
On Thursday 21st January 2011, the team at Bang! spoke to Simon Singh, PhD in Physics, science writer, and famous proponent for Libel Law reform at the British Association SciBar meeting at the Port Mahon pub. Philip: Simon Singh, welcome to Oxford’s British Science Association SciBar meeting and thank you for talking to us at Bang! Magazine. You’ve dedicated much of your career to talking about science and mathematics in an accessible manner. Why do you think this is important? Simon: Science has always been important, but we live
in an age where we have cloning, stem cell research, climate change and much more. Almost every area of our lives is affected by science and technology. I also think it’s part of our culture. If we look at cosmology and mathematics, subjects that I often write about, the research may have nothing to do with the practical side of our lives. We are curious, and understanding science is part of the joy of being human. And then thirdly, for me it’s just fun. I like science, I studied science and I wish I could have been a scientist, but the next best thing about being a scientist for me was to write about science. Nicola: So, how important do you think it is for the average person to understand the scientific method itself? S: When people leave school, I think they’re left with the view that science is cut and dried. So I think it’s important for people to learn that if you go to a scientific conference, it’s full of arguments and heated debates. If more people are aware of that part of science, then they would bear it in mind when science is in the news—is this discovery really important, is it certain, is it still disputed, is likely to be plain wrong? P: How do you see the role of social media in science journalism? S: There are many people who use Facebook, but not me. And I don’t even have a blog. I do twitter, but I’m a generation behind the people who really know how the new social media works and in that respect I’m a little bit nervous of it! I’m sure there’s huge potential out there. One of my favourite 23
stories recently concerned a chap called Rhys Morgan. He’s 15 years old and from Wales. He became aware of a treatment called ‘Miracle Mineral
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The discussion of ideas and activism in science is incredible.
Solution’, which has been used by patients with Crohn’s disease, which Rhys himself has. And he began to question this on bulletin boards and discussion boards and forums and so on, but he got rather a rough ride from those who read his thoughts. But because he was on the internet, because he could write blogs, he could tap into the resources of other people and they could support him and provide extra information. He could access databases, access articles in America, he could start really understanding what the problem was with ‘Miracle Mineral Solution’; it’s basically just bleach. Other people came to his support, and because of his blogging, trading standards have stepped in. Even as far
as Kenya, this stuff has been used to treat malaria and now the Kenyan government has stepped in. So the power of the internet, and blogging, in terms of the public understanding of science, the discussion of ideas and activism in science is incredible. N: Looking at the mainstream media— newspapers, TV and things, do you feel that scientific research is covered adequately?
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The job of newspapers is to sell newspapers, and the way they do that is by scaremongering.
S: The trouble is that there is just a huge spectrum of science coverage, and it is a very complicated picture. When I was your age, in addition to Horizon, there was Tomorrows World, Antenna, QED and more. And now on BBC1 there’s Bang Goes the Theory, and on BBC2 we still have Horizon, It appears to be a disappointing selection, but if you look at BBC4 just before Christmas, you have the Royal Institute Lectures, you have the Beauty of Diagrams, the Joy of Stats. Today we have a massive outpouring of science, but it’s on BBC4 so it’s quite tucked away. The landscape has changed so it’s hard to say it has been dumbed down, or to say it’s gone more highbrow. It’s just a much more complicated picture. Similarly, 20 years ago there was just BBC1 and BBC2, now there is National Geographic, the Discovery channel and more. There are fantastic resources on the internet, with people making brilliant YouTube science videos. So in one way you could say there is more wonderful science out there than ever before. However, I am worried that most people get their scientific news from the newspapers, and the job of newspapers is not to communicate science. The job of newspapers is to sell newspapers, and the way they do that is by scaremongering and sensationalising occasionally. We’ve seen the MMR scare, which I think was largely drummed up by the media on
the basis of a flimsy research paper. If the media had taken their role more responsibly, then I don’t think we’d have got into the mess we’ve got into, namely plummeting vaccination rates, which are only now recovering. P: You are about to start a tour with some fellow scientists called ‘Uncaged Monkeys’. Could you tell us a bit about the project? S: It’s fantastically exciting. It is the most extraordinarily exciting thing N: That’s imaginable, because when I was brilliant! Do your age this didn’t exist. There’s a you have any chap called Robin Ince, a well known wise words of performer, comedian and writer. His wisdom for any background is not really in science, but would-be science he has a love of science, a passion communicators? for science and in the last three of four years he’s been getting people S: I think, it’s tough. (scientists like There are lots of courses myself , Ben in science Goldacre and and the Brian Cox) and media, but saying: come there aren’t out of your comfort that many jobs. zone, step up on a So my advice stage, and explain would be: do whatever your science to the it is you would do otherwise. audience. Not just explain So if you want to do a postdoc it, but make it entertaining, or a PhD, then just carry on interesting and hopefully doing it. And if writing is your inspiring. So we’ve been thing, you can always do it in doing this in pubs, in small parallel. You can be a young theatres, in slightly bigger researcher and submit articles theatres, and now we are on the to New Scientist, submit articles verge of a national tour. I think we’re to the national newspapers, submit doing 14 cities in 2 weeks. Literally, articles to your local specialised one night we’re in Aberdeen, the next press, or student science magazine night we’re in Cardiff. I think every like ‘Bang!’. That’s the great thing, venue is over 1000 seats. One of the you don’t have to abandon a research venues, the Hammersmith Apollo is career or a career in industry. You can 3000 seats, and it’s just extraordinary do the two in parallel. . So that’s my that you can take advice, maybe not to Ben Goldacre, see it as an eitherBrian Cox, Come out of your or, but to maybe myself, Robin comfort zone, step do in parallel with Ince, we’ll have up on a stage, and what you’re already some guests as explain your science doing. Which is not well, and stick us to the audience. what I did, but that’s on a stage. It is another story! overtly scientific and geeky, but there are fantastic numbers of people out there who love Nicola Davis is a 3rd year DPhil science. In fact, we will be kicking off student in Chemistry at Worcester the tour at the New Theatre in Oxford College. Philip Bennett is a 2nd on May 1st. I think half the tickets are year DPhil student in Chemistry sold already and we’re still two months at Magdalen College. Art by Sam away from the first show! Roots and Samuel Pilgrim.
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Copy and Paste
Are you as quick as your own enzymes?
D
id you know that your body is able to replicate all of the DNA in a cell within an hour and only make three mistakes? Imagine having to copy out all 40 million words of the Encyclopedia Britannica twenty five times over, and making only one error. Even the most astute Oxford student wouldn’t manage such an incredible feat!
Bases are the chemical building blocks that make up DNA. Their order on the DNA strand codes the information
needed to make everything in your body. Using the template at the end of the article, try to determine the sequence on the new strand of DNA, given that Adenine (A) pairs with Thymine (T) and Cytosine (C) binds with Guanine (G). It should be fairly simple, but can you do it in 200 milliseconds (1/5th of a second)? Your body can. Yet, even at this impressive speed the replication process would still take about 700 days to copy all three billion bases of the DNA in once cell Instead, your body achieves it in just one hour by initiating replication at multiple sites across the DNA, using biochemical machines called enzymes to carry out specific reactions. DNA polymerases are a group of enzymes that form the new strand by moving along the template strand, adding the complementary bases and, if an
error occurs, removing any incorrect bases. As DNA is double-stranded, the strands must first be separated before its bases can be ‘read’. Thus, DNA helicase (another enzyme) unwinds the
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DNA helicase unwinds the strands at the speed of a jet engine.
strands at the speed of a jet engine, allowing enzymes to bind onto them. Enzymes are indeed the biological superheroes that live within us all. A T G C A T G A C C .…..…….….….….….….…................... Jessica Beeson is a 1st year undergraduate Biochemist studying at Lady Margaret Hall. Art by Samuel Pilgrim.
Going Up in Smoke Psychological Effects of Lighting Up
F
rom bleak adverts on the TV to black edged notices on cigarette packets, it is well known that smoking kills. However, little attention has been paid to its effects on mental health. General opinion has been that the mentally ill turn to smoking to alleviate short-term symptoms of anxiety and depression, but a more causal link has been investigated, based upon a study on teenage smokers by Dr Naomi Breslau at the Henry Ford Hospital, Detroit.
The study analysed 1000 teenagers who had a history of daily smoking before the study began. Over a five-year period, the risk of these individuals developing severe depression approximately doubled, suggesting that smoking could predate mental illness. In a later study, Breslau found that
smokers are three times more likely to develop long-term panic disorders than non-smokers. This link was confirmed by large-scale studies (controlling for socio-demographic factors) showing that people who are anxious or depressed were twice as likely to smoke, and up to 80% of those with psychotic disorders (e.g. schizophrenia) are smokers. A possible causal mechanism explaining this relationship between smoking and panic was suggested by Breslau’s co-worker Dr Donald Klein. He proposed that impaired lung function, inducing a feeling of suffocation, is caused by cigarette smoking, and triggers panic attacks. This “false suffocation” theory is principally psychological—a more physiological cause of mental illness may lie in the nicotine induced stimulation of two chemicals in the 25
brain which cause an increase in heart rate and blood pressure, and at higher concentrations can set off panic attacks. It is probable that nicotine’s stimulant effect, combined with the carbon monoxide in smoke work together to cause the symptoms of psychological illness. It is still a major concern that little is being done to help mentally ill smokers to quit, despite the fact around 50% of smokers in mental institutions wish to do so. The health profession must be made aware that nicotine dependence is potentially the most common, most deadly, most expensive, and yet most treatable cause of psychiatric disorders. Isobel Steer is a 1st year Biology undergraduate at St. Hilda’s college. Art by Rebekah Pawley.
Whipping up a Storm
The thundery task of predicting the weather. Why is it so hard?
I
magine placing a ball on top of Mount Everest, and giving it a nudge. An enormous range of landing places may be achieved by only a tiny difference in the initial direction of the push. This behaviour is known as sensitive dependence—two initially almost identical trajectories will lead to completely different results. It is fiendishly difficult for scientists to model and predict, but an understanding of Chaos—as this behaviour is known—is essential to the study of many physical systems. It is chaos that makes predicting the weather so hard. As a weather obsessed country, we know that two sunny mornings in a row doesn’t always mean two sunny afternoons, no matter how similar the skies look at 11 am each day. The weather displays sensitive dependence, and in order to predict it, so must our best weather models.
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Chaotic systems such as the weather are temperamental.
Remember Everest? Well our ball only had one initial condition determining its future (the direction of the push), the weather has many more. Indeed, our best models have over ten million conditions factored in, and even so, they are still not perfect. It is tempting to suggest that we can build a model from scratch simply using the laws of physics. This is unfortunately not the case—in fact some argue that chaos has forced us to re-evaluate whether it is ever really possible to have a truly successful physical model of any complex system. There are approximately 1045 molecules in the atmosphere: precise movements of each may determine the course of the weather. It is hard not to be pessimistic about the possibilities of modelling on this level! The British public still expect a forecast. Yet we are faced with model inadequacy and measurement inaccuracy. What can we do about it?
To refine the model, forecasters use ‘shadows’. A shadow is a prediction that our model has generated from given data. By using data from the past we can compare the shadow prediction to what the weather actually did. Ideally, we would like our shadow to closely follow these observations— then we can be reasonably confident that our model is a good one for predicting future weather. Early in the development of weather prediction, forecasters would run their best model once a day, get a shadow, and then call that the forecast. As computers became more powerful, the models became more complex, and the predictions became better, but fundamentally the same problems remained. Chaotic systems such as the weather are temperamental. In some situations, an error in the initial measurements may not completely derail the predictions, but in others the system is so sensitive that even the smallest errors will render a forecast useless. In the past, forecasters only had one shadow to use, and the inevitable chaotic behaviour of nature meant that, even with the best possible shadow, it would sometimes do something completely unexpected. So, instead of running a complicated model once, and programming in only one weather report, current forecasters run a simpler (to save on computational time), and thus inherently less accurate model many times, each time starting the system off in a slightly different initial state. This is known as ensemble forecasting. Ensemble forecasts allow us to see possible behaviours we may have missed if we only had one shadow and, more importantly, they allow us to quantify the reliability of our forecast. If all of our shadows cluster together, it seems to suggest that our forecast is a reliable 26
one, whereas if each sped off on a completely different course, it would be hard to put out any forecast with confidence. We might further improve our ensemble forecasts, and use several different mathematical models, each with its own forecast ensemble, and compare them all. If all our models gave similar shadows, we might hope our predictions really were close to the truth. Unfortunately, in practice we find that, although our models each individually give ensemble forecasts grouped together, the prediction the shadows group around differs from model to model. All these models suffer some form of inadequacy. Weather prediction is an immensely difficult science, and these are just a fraction of the problems that forecasters have to deal with. So next time you end up in a thunderstorm in shorts, perhaps you will have some small sympathy for the weatherman. Jack Binysh is a 2nd year undergraduate Physicist at Lincoln College. Art by Rebekah Pawley.
Women are Wizard from Mars, of the Men West are from Venus
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“Nature and Nature’s laws lay hid in night. God said, ‘Let Tesla Be’, and all was light.”
W
ith these words, Dr Bernard Behrend honoured his friend Nikola Tesla at the 1917 presentation of the American Institute of Engineers’ Edison medal. The honour is welldeserved given that Tesla’s numerous revolutionary inventions include both the modern electric motor and a highly efficient method of transmitting electricity. Yet Tesla died alone in a New York hotel room, with significant debts and a tarnished reputation. How did he come to such an ignominious end? The story begins with the arrival of 28-year-old Nikola Tesla in New York with just four cents and some calculations for a flying machine in his pocket. An eager inventor from a young age, he developed his passion for engineering at the Austrian Polytechnic in Grazt. He never completed his studies, instead taking up a post as the chief electrical engineer at the Continental Edison Company in France. His work developing engines earned him a letter of introduction to Thomas Edison himself, in which Edison’s colleague Charles Bachelor stated: “I know two great men, and you are one of them: the other is this young man.”
WhyThe we should bizarreall lifecome of Nikola backTesla to Earth... to DC, electrons in an AC system periodically reverse direction. In a coil of wire, a current of changing direction can induce a changing magnetic field, and vice versa. Therefore, if two coils are in close proximity, AC flowing in the first coil will induce a magnetic field in that coil, which will in turn induce an alternating current in the second coil. If the second coil has fewer turns than the first, the voltage across the second coil will be lower than that across the first. This is the basic operation of a transformer which allows the conversion of high voltages into lower voltages for domestic use. Tesla quickly completed his work on AC generators, but upon asking for the $50,000 he had been promised, a guffawing Edison dismissed him, saying “Tesla, you don’t understand our American humour”. Tesla resigned immediately, and worked feverishly on a new invention: the first ACpowered motor (at the time electric motors could only run on DC), which he demonstrated in 1887. This was the key to establishing the applicability of AC as a source of electricity for American homes and businesses. On hearing of this great new invention, industrialist George Westinghouse employed Tesla to convert his powerplants to AC. Fearful of losing his
monopoly, Edison began lobbying legislators to ban AC, and later resorted to organising public lectures on ‘the dangers of AC’. At the height of what became known as ‘The War of Currents’, Edison approved a demonstration of these dangers in which AC was used to kill a circus elephant. Despite this negative publicity (and needless animal cruelty) Tesla’s system triumphed.
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He was a dreamer with strange, futuristic ideas, who gave lectures in the spectacular style of a magician.
However, this victory did not secure Tesla’s place in American hearts. He was a dreamer with strange, futuristic ideas, who gave lectures in the spectacular style of a magician, earning him the title ‘Wizard of the West’. Distaste for such showmanship grew, and Tesla became reclusive, remained unmarried, and lived only in hotels. This combination of strange habits and unconventional science turned him into an ‘evil genius’ in the eyes of the public, which led to his immortalisation in popular culture as the first mad scientist villain fought by Max Fleischer’s Superman. And so it was—alone in the Hotel New Yorker—that Tesla died. In more recent years, he has been better appreciated—Tesla’s name graces a planet, a prestigious scientific award, a much loved school laboratory toy, and the standard unit for measuring the strength of a magnetic field. There is even a rock band called Tesla—fitting tributes to a great inventor, and the man who powered our world.
With this recommendation, Tesla met Edison and was promptly assigned the task of redesigning the system of direct current (DC) generators at The Edison Machine Works. In a DC system, the flow of electrons is unidirectional, and continuous. Transmitting DC over long distances requires a high voltage, which, at its destination, is difficult to convert to a lower, safer level. Edison therefore transmitted lower voltages over shorter distances, requiring an expensive network of power stations near to the communities they served. Tesla’s revolutionary idea was to use an alternating current (AC). In contrast
Alisa Selimovic is a 2nd year DPhil student at the Institute of Biomedical Engineering, modelling growth of cerebral aneurysms. Art by Leila Battison.
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Women Riddler’s areDigest from Mars, Men are from Venus Cerebral amusement for the modern Whyscientist we should all come back to Earth...
Across 1. An enzyme perhaps, for the icon missing hearts (7) 4. Headcase puts first of Northern Ireland and last of Peru in pack (7) 8. Before guard, style or boat (4) 9. North or South in Interpol exist the same (4) 10. Twice headless young reverted to a beast (3) 13. Unlikely to conceive upon a tablet (2,3,4) 14. Sound bouncing around nymphs (6) 16. Scientist in rates law (5) 18. Sounds like hello to each but overexcited (5) 22. Religious education leads a spiritual faction in surgery (6) 23. Conducting helices confuses oldies son (9) 24. Storing energy initially as the power (3) 26. Half a horse consumed logic or garden for example (4) 27. In Paisleys small land (4) 28. Strangely ignored the gradually reducing material (7) 29. Celestial bodies have vegetation around the East (7)
Down 1. Closed figure sounds like dead parrot (7) 2. None left before workshops smells (9) 3. Move pronto and get your prime traitor in order without river—this turns not quite right (8,8) 5. Whenever he let it in without one about has to dream it up again (8,3,5) 6. Cold stuff like Swiss trains (3) 7. Just a minute before culls shifted—spineless! (7) 11. Greeting to Vera is as soothing balm (4) 12. State of matter or moon—perhaps about without public relations (5) 15. Have a quick word concerning a drug (5) 17. Not yours between clues about to glow (9) 19. Smoothing metal (4) 20. Brother at lowest before drug. It’s elemental! (7) 21. I require help about French sea taking different forms (7) 25. The earth flusters the I (3)
Puzzle devised by Hannah Hogben, a 3rd year DPhil student in Physical and Theoretical Chemistry at Oriel College.
28 Untitled-1 1
04/02/2011
w w w . b a n g s c i e n c e . o r g