SATNAV Issue 12

Science And Technology News And Views Magazine

We interview Nobel Laureate in Chemistry Sir Fraser Stoddart plus much more in our SCIENCE OF THE EVERYDAY issue

What is SATNAV? SATNAV is the student-led bi-annual science magazine at the University of Birmingham.

If you have an interest in scientific writing then this is a great opportunity to get some experience and practice. We cater to a wide range of scientific tastes from Psychology to Quantum Physics!

The committee provide editors and feedback aiming to create an informative, factual and interesting magazine, with an issue published at the end of the Autumn and Spring Terms.

At SATNAV, we encourage creativity in expressing our interests in science.

As well as accepting written submissions to the magazine, we also accept artwork submissions!

How can I get involved?

Enjoy writing about your favourite science topics? Want to give it a go? We want to hear from you!

Get in touch with us at satnav@guild.bham.ac.uk or alternatively, any of the committee members.

Join our society at guildofstudents.com Join our Facebook group and like our page: S.A.T.N.A.V Magazine Follow us on twitter: @Satnavmag See our previous issues: issuu.com/satnavmag Read our website: tiny.cc/satnav

Issue 12

Chair Sara Jebril SMJ472@student.bham.ac.uk

Burner Phones Justin Holloway takes a look at the infamously incendiary Galaxy Note 7

Vice Chair Marion Cromb MXC414@student.bham.ac.uk

From Snorlax to Science Hope Steadman asks what's next for AR

Treasurer Mel Jack MXJ505@student.bham.ac.uk Secretary Daniel Thomas DXT439@student.bham.ac.uk Layout Editors Marion Cromb MXC414@student.bham.ac.uk Federico Abatecola FXA551@student.bham.ac.uk Life Sciences Editor Joanna Chustecki JMC430@student.bham.ac.uk Physical Sciences Editor Kitty Morelli-Batters KIM481@student.bham.ac.uk Technology and Review Editor Philippa Jefferies PAJ390@student.bham.ac.uk Copy Editor Isabelle Hayden ILH600@student.bham.ac.uk Publicity Editor Amy Cunningham AXC527@student.bham.ac.uk Website Manager Matt Scourfield MRS493@student.bham.ac.uk

The Father of Molecular Machines Joanna Chustecki and Mel Jack interview Professor Sir J. Fraser Stoddart Radar Revolution Patrick McCarthy reveals how UoB's wartime research made it into your microwave Coffee Chemistry John Dunsmuir breaks down the effects of caffeine on the body Fancy Flows Marion Cromb and Daniel Thomas expose the invisible beauty of fluid dynamics Reliance on Relativity Philippa Jefferies on the science behind GPS Parasitic Pets Cat Collins wonders if our feline friends might actually make us crazy Stunning Sunflowers Chyi Chung on how mathematical patterns dictate natural beauty DNA Hard Drives Zidan Yang unlocks the memories of cells

Distance A poem by Jade Sadler

FRONT COVER BASED ON ORIGINAL PHOTO BY JOHN JAMES

December 2016 | SATNAV | 3

Ode to the Short-Lived, Bright-Burning Samsung Galaxy Note 7 Justin Holloway mourns the missed opportunity to have your own personal, portable haystack.

W

hilst relocating to Old Blighty from Down Under, I was warned by Sharon, the air hostess, ‘oi mate, you better not be carrying a Galaxy with ya’.

Fortunately, I was equipped with an iPhone and could use the 24+ hour flight to catch up on podcasts.

Since then further aircraft carriers in Australia, Asia, Europe and America have banned the Samsung Galaxy Note 7 from being carried on or packed in luggage. Samsung has also taken the phone off the s has issued a tphones in of the lures in tech tion about? one so

A couple of months ago the Galaxy Note 7 was released. It was billed as one of the best phones of 2016, however soon dangerous problems started to arise when, like a haystack, the phone would spontaneously combust.

According to the US Consumer Product Safety Commission, in these first few months ‘Samsung received 96 reports of batteries overheating including 13 reports of burns and 47 reports of property damage associated with Note 7 phones.’

Initially Samsung announced a broad recall. This involved issuing customers with new replacement Note 7 phones with particular insignia to suggest they were safe.

"One of the most costly product safety failures in tech history."

However even replacement Galaxy Note 7 phones exhibited the same problem.

Michael Klering, from Kentucky in the US told WKYT, a local news station, that he awoke early morning and realised his new phone had spontaneously combusted, filling his entire room with smoke. He was admitted to hospital for smoke induced acute bronchitis. He said “My phone was supposed to be the replacement, so you would have thought it would be safe. It wasn’t plugged in. It wasn’t anything, it was just sitting there.”

Eventually the company stopped production and issued the following statement: “We are working with relevant regulatory bodies to investigate the recently reported cases involving the Galaxy Note 7. Because consumers’ safety remains our top priority, Samsung will ask all carrier and retail partners globally to stop sales and

Issue 12

exchanges of the Galaxy Note 7 while the investigation is taking place.

We remain committed to working diligently with appropriate regulatory authorities to take all necessary steps to resolve the situation. Consumers with either an original Galaxy Note 7 or replacement Galaxy Note 7 device should power down and stop using the device and take advantage of the remedies available.”

Some sources, including the NY Times, have suggested that Samsung does not fully understand what is causing the phones to catch alight and that production of the Note 7 was rushed.

Furthermore, the phone was not fully tested by their engineers prior to release.

So why are they overheating? The Samsung Note 7 uses a lithium ion battery for power, which is a type of rechargeable battery in which lithium ions move from the negative

From Snorlax to Science

electrode (anode) to the positive electrode (cathode) during discharge and the reverse when charging. The electrodes are divided by a porous separator, containing a liquid electrolyte, which allows ionic movement but prevents contact between the two electrodes.

If the electrodes were to come into contact, a short circuit would occur. As the lithium ion battery uses a highly flammable electrolyte, this causes ignition and heating. At 100°C the materials begin to break down causing further heating until the battery ultimately catches fire.

Some reported scenarios which could

cause the electrodes to come in contact include: • Manufacturing defects • Damage • Scrap metal left in the battery during manufacturing.

• Lithium plate concentration in recharging causing shorting and combustion.

Perhaps we are coming to the limits of the lithium battery systems. There are many others with good characteristics which do not use a highly flammable electrolyte. Nickel metal hydride battery systems, for example, are selected in vehicular applications because they are safer and more tolerant of damage.

The marketing team at Samsung did not include in their dossier of features that the phone, like a personal and portable haystack, would undergo spontaneous combustion. Let’s hope it’s the last device that has this capability.

or development...now, businesses can physically see how schools, hospitals or roads will lie on the land. It can be utilised in everything from navigation to interior design.

But most important is its impact on the world around us. The increased connectivity and interactivity with the natural and physical environment is a step that can lead to more environmental and social responsibility. Applications in disciplines such as environmental science and engineering will shape and reshape our environment.

So whether it’s catching Pikachu, Charizard or Bulbasaur, AR will continue to occupy and influence everyday science.

Hope Steadman

ARTWORK: MOHAMMED HUSSAIN

Augmented reality is fast becoming a technology of the everyday for millions around the world. Pokémon Go may have seemed like a simple mobile game, yet it signalled the arrival of AR into mainstream public consciousness. The ability to conjure and overlay virtual objects onto the real world is not just a defining advancement in the gaming industry, but also in how we live and operate on a day to day basis.

Our tablets and phones can act as interfaces to visualise a different reality, opening up endless possibilities not just for the individual. Forget pages of blueprints needed for construction

"Samsung did not include in their dossier of features that the phone, like a personal and portable haystack, would undergo spontaneous combustion."

December 2016 | SATNAV | 5

PHOTOS: JOHN JAMES

The Father of Molecular Machinery: An Evening with Professor Sir J. Fraser Stoddart Interview and article by Joanna Chustecki and Mel Jack With thanks to the EPS Community and Alumni Relations Office

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cold autumnal night on campus and somet hing incredible is happening in t he Hawort h building. Hundreds of students, postgrads, old friends, colleagues and members of t he public have flocked to t his well-established house of chemistry to hear one of t he greatest chemists of our time talk.

Professor Sir J. Fraser Stoddart to be exact. Wit hin t his huge crowd bust ling to access t he main lecture t heatre stands a man who has published over 1,000 scientific papers, is one of t he most cited chemists in t he world, and has, on t he 5 of October 2016, been awarded t he Nobel Prize in Chemistry ‘for t he design and synt hesis of molecular machines’.

SATNAV are extremely excited to be able to share wit h you our interview wit h Sir Fraser, where we learnt about his work wit h molecular machines and heard his side of t his incredible story.

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Jo: So you're back in Birmingham, in the very building you spent time in as Head of the School of Chemistry in the ‘90’s. What moments do you particularly remember about your time at the University?

“I have very happy recollections of being here. This was when a lot of the very important breakthrough work was done. The attitude, commitment and excitement in the group was at its height. We had been provided with a set of newly refurbished laboratories, on the 7th floor of the Haworth Building. The only thing that didn't get refurbished was the toilet. Once the Duke of Kent visited and they had to replace the chain on the toilet with a gold chain – I always remember that incident. Although there were many funny incidents like this one. But I have very pleasant recollections of my time at Birmingham, and surely we would have stayed if my wife's physical

condition hadn't begun to deteriorate, but we thought we would get better care for her by going to UCLA. So, there were many factors, but that's what life does to you.”

J: Yes, absolutely. How do you think your time at Birmingham has gone on to influence the rest of your career?

“It has all happened in an incremental kind of way. We had started to make some significant breakthroughs as I left Sheffield, the move to Birmingham acted as a foot up to take us to the next level. Entering a new academic system at age 55 in the United States, I had to learn a lot of new ropes. For Norma and I, since she was still fit during that early period, it really was a steep learning curve. But because of the great deal of accomplishment and self-confidence gained at Birmingham, the learning curve could be surmounted.”

Issue 12

J: In an earlier conversation, you were speaking about the benefits of travel as a research scientist. Do you think your move from Birmingham to the United States had an impact in shaking up your ideas?

“Oh, yes. But 'chemistry' seems to be different in every different department of every different university I've gone to. And so you meet new people with new takes on what they do in research.

At UCLA I met Jim Heath who took me into Molecular Electronics, and I met Jeff Zink who worked on drug delivery systems together with me. I'm a great advocate of change – there might be another change in me yet. I've been at Northwestern for 10 years. One time we counted that the average time taken for me to move is 7 years. I also like looking at different parts of the world, and cultures. I wish I had the gall to move to somewhere like China or Japan, for that would be an even bigger challenge.”

Mel: With a scientific career spanning over 50 years, what within your work and your academic career did you find most challenging?

“The most challenging were the early years. I met a hierarchical system

in Sheffield that held me back in my development, I feel. I've no grudges and I don't bear any malice on anyone, it was just a matter of that's the way it was. But the good thing about it was that it left me absolutely determined that I would support young people, through thick and thin, for the rest of my career. I would not model myself on the people who had supposedly been my mentors in the past.”

M: What do you think has been key to your development as one of the world's leading scientists in the field of molecular nanotechnology?

“Many many things. I think it started with me being an only child on a mixed-arable farm in Scotland 12 miles south of the capital. Tucked away, we didn't have electricity until I was 17 years of age, so we had to make do, as you might imagine. And then I was mixing at school in Edinburgh with boys and girls that had all these mod cons. I also saw a revolution in farming that left an impression on me that you must keep moving on. I've therefore taken that over into my life as a researcher: you can't stay still. You've got to be moving on. Every day. Every week. Every year. That's what we do.”

J: The Nobel Prize has been awarded to you, Ben Feringa and Jean-Pierre Sauvage for the fundamental discoveries of mechanical bonds being wielded to make molecular machines.

What was it that drew you to this area of study? Were the consequences of this technology to the world known to you when you started out?

“I had no image of technological applications when I started out. The driving force was simply to find out if we could do something no one had ever done before. I was never a happy passenger in undergraduate teaching labs, because I knew that these experiments had been carried out for years with hundreds of students each year, so at best you were being trained in techniques. The reason for doing it was not firing me up. It was when I was given the opportunity to look at something for the first time that nobody had done that I really got fired up about research.

"You can't stay still, you've got to be moving on, every day, every week, every month. That's what we do."

December 2016 | SATNAV | 7

"The driving force was simply to find out if we could do something that nobody had ever done before."

The progression to molecular machines was slow, of course, over decades. I wasn't thinking about molecular machines in the ‘70s back in Sheffield, or at ICI (Imperial Chemical Industries). I wasn't even thinking of them through the ‘80s until we published the molecular shuttle in the Journal of the American Chemical Society. And that's when my mind flipped and I could see that we had the basis at least for a switch. I had to fight to keep that statement in the paper at the very end. I think the difficulty in being a creative person is that you've got to take a lot of criticism and a lot of disbelief on the part of your colleagues. They would say "ultimately it's nice but it's exotic, what is it good for?" Well I think, finally, Stockholm have answered that question. It must be good for something, or they would not have recognised itt.”

M: I guess you particularly enjoy the creativity that comes with chemistry, although some would think of it as a rather strict discipline.

“They're wrong – it's a highly creative discipline and this was pointed out by Marcellin Berthelot in 1860 when he said “chemistry creates its own object, which distinguishes it from the natural and the physical sciences”. Now, one doesn't want to say that other scientists don't make things either – they do.

But in chemistry the core for me is synthesis. So I go on and say making is very very important, followed by measuring, followed by modelling. Three 'M's. You can liken this activity to people who paint, sculpt, or write. It's the same kind of challenge. That is unique to chemistry as a science, I think.

I've been likened to J.K. Rowling, for example, and I'm a bit overawed by that comparison. I'm certainly not as rich as J.K! Rowling. But nonetheless, I think therein there is a good reason for a comparison. Do something that you enjoy doing, and one day it will capture the imaginations of many people.”

PHOTOS: JOHN JAMES

J: For our current issue, SATNAV are focusing on 'The Science of the Everyday'. Do you believe that eventually this technology will be developed for use in our everyday lives?

“Yes. I was answering a question along those lines after my lecture and I put it in the context of flight. I think it was somewhere around 1927 when things were going very badly wrong. Of course, a few people made it across the Pond – and there were a few successes but there were also a few disasters, sadly. So I think we're going through this phase – not in terms of human suffering, but of getting the science to create good technology. How many years or decades it will take, I don't know, but it's absolutely mind-boggling how being able

to control matter down at the sub-nanometre level with the exquisiteness that we know we can is bound to have huge repercussions on developments in information technology and medicine.”

Alumni Relations: With your award and the two in physics this year, that brings the list of Birmingham's Nobel Prize winners up to 11. Why do you think the University has had so many?

“I think the UK in general gets so many because there's something about an island culture that encourages creativity.

I think as a nation, we get quite a lot of people thinking out of the box. People who are prepared to take risks. Maybe Japan shares that with us, because of the fact that it's an island culture – and they can be creative while staying isolated from the rest of the world. People leave the UK very simply because there's a common language across the Pond.

One level of creativity, is expressed in playfulness and fun; the tendency to even want to break rules, and be a bit awkward at times. I think that surfaces in this British culture extremely well.”

AR: As you mentioned in your lecture, the work that you do still gets you up in the morning and gives you that drive and ambition. What would you still like to achieve?

“I think it's more down to people. From the perspective of Northwestern University who are knocking at the door of having the best chemistry department in the world, a test of their success would be to have our students and postdocs being appointed as Professors in the top schools in America.

I’m talking about seeing my students going to Harvard, MIT, Yale, Princeton, Caltech, Stanford, or Berkeley. I want to train as many people as possible, to get them into the most privileged of environments where they have high chances of succeeding to the level of or beyond the level that I have achieved. It makes a difference, being alongside some of the brightest people in the world. I think because I'm more invested in people than in the research as such, I’d like to help people be able to achieve their full potential. But that means staying at the cutting edge of research.”

And continuing t he development of some of t he chemistry’s most exciting work, staying at t he cutting edge of research will be exact ly what Sir Fraser, his many students and colleagues will be doing for years to come.

We hope t hat our readers have enjoyed t his interview as we have hearing Sir Fraser talk about his work. Through his lecture and subsequent interview, we were fortunate enough to able to gain and share an insight into t he life of one of t he worlds’ leading scientific minds.

Birmingham and the RADAR Revolution Patrick McCarthy uncovers the link beween your microwave, your uni and World War Two.

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ow does a microwave oven work? Finely tuned electromagnetic (EM) waves form standing nodes inside the oven’s chamber, exciting the bonds in water, causing them to heat up as the contents spin on the plate. The source of these microwaves, the cavity magnetron, has a history directly linked to the University of Birmingham.

In 1939, the term RADAR (Radio Detection And Ranging) was coined.

Systems had been developed over many years whereby objects could be detected with several-meter resolution from large distances. Originally intended to help prevent the collision of ships in fog, RADAR works by sending out short, regular radio wave pulses and measuring the reflections observed on an oscilloscope. By timing the pulses’ returns, the range of the object they reflect off can be determined.

However, for RADAR to work it needs a ‘coherent’ wave source - one which consistently produces radio waves of similar wavelength. This proved to become more difficult as the radio waves climbed to higher energies.

However, higher energy waves correspond to shorter wavelength radiation, which means better ‘resolution’- the smallest object the antenna can detect. This meant that, early in the Second World War, it was possible to detect objects such as approaching planes; but being able to resolve how many planes incoming proved to be difficult.

A major breakthrough came from Birmingham in 1940, in the form of the cavity magnetron. This device uses several specially shaped cavities inside a vacuum tube, and passing a magnetic field through the length of the tube allows electrons emitted from a cathode in the centre to spiral around the cavities. This resonates and, as described by Maxwell’s laws, the moving charge creates electromagnetic waves corresponding to the frequencyin this case, radio.

John Randall and Harry Boot are credited with its creation, though it was not the first. A multi-cavity magnetron had already been patented in Berlin five years prior, however it suffered

from ‘frequency drift’, where the radiated wavelength would change as the magnetron warmed up. This made it unreliable for radar, but Randall and Boot solved this problem by liquid cooling the chamber and increasing the magnetic field. This design could produce 1000 times the power of other devices at the time, and resolve objects with metre widths.

"Randall and Boot’s design was deployed across Britain in radio stations, helping win the Battle of Britain and arguably the war."

It has been argued that this breakthrough in coherent EM technology was a ‘simultaneous discovery’, invented across several countries (such as Germany, the US, Japan and the Netherlands) in the space of over a year. However, Randall and Boot’s chambered design proved to be readily manufacturable, and as such it was easily deployed across most of Britain in radio stations, helping win the Battle of Britain and arguably the war.

Today, there are more sophisticated devices such as ray tubes being used as sources, and the cavity magnetron has dwindled in military use. However, you can still find them today in most conventional microwave ovens and older radio devices.

TOP LEFT: REPLICA OF THE ORIGINAL CAVITY MAGNETRON INVENTED AT UOB. TOP RIGHT: REPLICA OF THE BOTTOM LEFT: ANODE BLOCKS PHOTOS: © THE UNIVERSITY OF BIRMINGHAM RESEARCH AND CULTURAL COLLECTIONS, COLLECTION OF HISTORIC PHYSICS INSTRUMENTS (BIRMINGHAM.AC.UK/FACILITIES/RCC/)

ELECTROMAGNET FOR THE ORIGINAL CAVITY MAGNETRON.

Issue 12

What Is Caffeine?

John Dunsmuir takes us on the journey coffee makes through our body.

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hree hundred tonnes of caffeine are consumed globally each year, making it the world’s most popular psychoactive drug. But what makes this insecticide so popular?

The first credible source of coffee drinking comes from Fifteenth Century Sufi monasteries in modern day Yemen. It quickly spread via trade throughout the Mediterranean Basin, entering Europe via Italy.

consumption, the number of adenosine receptors increase so larger doses are required over time. However, being awake isn’t the only consequence of caffeine consumption.

To understand further effects requires a look at the breakdown products of caffeine: paraxanthine, theobromine, and theophylline. Each are produ

"Caffeine closely resembles the structure of a naturall occuring chemical in the brain known as Adenosin However, to understand caffein requires a detailed look at the chemistry of the compound. Caffei closely resembles the structure of a naturally occurring chemical in the brain known as Adenosine (which it is produced from the breakdown of A in the body). Adenosine receptors in the brain bind adenosine; this is believed to play a key role in regulating circadian rhythms (or sleep cycles). However, due to caffeine's similar structure, it also bonds to these receptors and blocks adenosine from binding. By doing this, caffeine wards off drowsiness by inhibiting the build-up of adenosine in the brain, thereby disrupting the body’s natural circadian rhythm. For a healthy adult, caffeine is metabolised quickly, with a metabolic half-life of 5.7. After which the adenosine again bonds, causing a caffeine crash.

Additionally, with regular caffeine

mole nown as a methyl group). This means each compound has the same number and type of atoms, but different structures causing different effects on the body.

Beginning with the most common breakdown product at 84%: paraxanthine. Paraxanthine increases fat breakdown; fuelling muscle activity and increasing athletic performance. It is this chemical, over the other two breakdown products, which makes caffeine a popular ingredient in sports drinks.

Secondly at 12% of breakdown products: theobromine, which causes an increased flow of oxygen and nutrients to the brain. This benefits memory retention and cognitive functions, beneficial for completing complex tasks.

Finally, accounting for only 4% of breakdown products: theophylline, which increases heart rate and concentration. This product makes caffeinated drinks dangerous for those ith heart problems whilst ultaneously benefitting tired dents. ong-term caffeine consumption lso interferes with the production f dopamine, serotonin, and in oses exceeding 500 mg a day, orepinephrine (known as the appy Chemicals), which can lead anxiety and depression if over sumed. It is for this reason that mg of caffeine a day (or three to r cups of coffee) is considered the afe limit for consumption. However, this shouldn’t dismay coffee-lovers, as at around 200 mg per day (approximately 2 cups of coffee) any risks are negligible but the benefits to concentration, memory retention, and cognitive functions (such as problemsolving skills) make this a recommended daily amount by some doctors.

Regardless, when used in moderation, caffeine has significant cognitive benefits, and with 5000 coffee shops nationwide, this craze appears to be here to stay.

December 2016 | SATNAV | 11

12 | SATNAV | December 201

PHOTOS: MARION CROMB & DANIEL THOMAS

What a Load of Hot Air! Marion Cromb and Daniel Thomas reveal the invisible beauty of the world around us with schlieren imaging.

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ook here, there's something cool happening! No, not just on the page, but in the air in front of it! There are many interesting phenomena taking place all the time in the air surrounding us, but their transparency normally makes them difficult to admire. However, certain techniques are able to pick up on slight changes in the way materials bend light, allowing us to see the otherwise hidden beauty of air flow and much much more.

It all relies on a fundamental property of light. The speed of light is inversely proportional to the refractive index of the medium it is travelling through. Slight variations in the refractive index of a medium are often caused by variations in density. In air, cold regions will be denser, and light is bent towards those regions due to their higher refractive index. When light passes through a boundary between two materials of quite different refractivity, such as from water to air, the bending of light is obvious – objects are noticeably distorted. But subtler refractive index changes, such as those due to the heating of air, are too hard to observe with the naked eye unless something amplifies the deflection effect.

A simple way to amplify this effect is the shadowgraph method. This simply involves shining light through a

transparent medium with varying refractive index, and observing the shadows. Light is bent away from less dense regions, and these areas will refract light outwards to form a bright fringe around an inner darker zone.

This change in illumination is strongest at the boundaries of these areas. Shadowgrams occur frequently in everyday life, such as the dancing shadows cast by the air above a hot toaster or a candle flame, or the intricate shadows formed by light passing through a wine glass. Some ocean predators even use the shadowgrams cast onto the seafloor by transparent prey to identify their next meal!

Schlieren imaging is a more sensitive method which uses a boundary edge to view variations in refractive index (‘schlieren’). The boundary shows up ray refractions perpendicular to its edge. The simplest variation is ‘background distortion’, where light-dark boundaries are distorted by schlieren in front of them.

This is often seen in the ‘wobbly air’ above hot roads. However, this method is only sensitive along the boundaries.

A more reliable schlieren method requires lenses or a mirror to focus the schlieren image. Light passing through a schlieren source is focused to a point and a boundary is placed at this point.

Light deflected by the schlieren misses

the original focus point and moves across the boundary. Small differences in light direction are therefore translated into light amplitude or colour differences in the schlieren image. This process was used to produce the images on this page. By using a variety of cut-off filters, a huge range of different lighting effects can be achieved.

"Shadowgrams occur frequently in everyday life, such as the dancing shadows cast by the air above a hot toaster" Different fluid flow phenomena are observed with these techniques. The mushroom-shaped plumes are examples of Rayleigh-Taylor instabilities which occur when a denser fluid sits above a less dense fluid. The mass of air heated by the lighter flame is buoyant and so moves upwards. Friction from the surrounding cold air slows the outer hot air relative to the air in the centre. This pulls the outer air around and down to create the mushroom shaped plume.

The faster inner air drags in the outer air in its wake, creating a vortex ring that travels upwards. Rayleigh-Taylor instabilities often lead to KelvinHelmholtz instabilities: waveforms associated with boundaries between fluids moving at different velocities.

These occur on the edges of the candle plume; as the buoyant air gains speed, the instabilities become larger and the plume turns turbulent.

December 2016 | SATNAV | 13

Einstein's Relativity and How Not to Get Lost Philippa Jefferies looks at how Einstein's theories affect us every day through our GPS devices.

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e’ve all heard of Einstein’s theories of Relativity, even if only by name. They’re often associated with black holes and other immense objects in space and they dictate the movement of objects from our own planet to vast galaxies.

However, the consequences of Special and General Relativity affect us more personally every day. A good example is the GPS on your phone!

GPS, the Global Positioning System, is now available on every modern phone and SATNAV. GPS can be an extremely accurate way of determining your location, however without taking into account relativistic effects your high-tech phone would give you a location a few miles from where you are actually stood - which would be rather inconvenient if you were in a hurry to get somewhere!

Einstein’s theory of Special Relativity describes how observers moving at different speeds view each other, and can be summarised as: 1. The laws of physics are the same for

14 | SATNAV | December 2016

everyone (in all frames of reference) 2. The speed of light is always the same.

Even if a person is travelling much faster than someone else, they both see light travelling at the same speed, resulting in them experiencing time differently.

"Clocks in a higher orbit tick faster than those on Earth" General Relativity also affects the way you experience time. One of the main ideas of the theory is that unless you have an outside reference, you cannot tell if you are stationary or accelerating in any direction. This means if you are in a gravitational field, you can also be seen as accelerating which affects the rate of time. For this reason, clocks in a higher orbit tick faster than those on Earth.

These effects need to be taken into account by any GPS system. GPS utilises satellites orbiting the Earth, which emit signals with information about their position and the time the signal was sent. Your device receives these signals

and by using the differences in the times taken for the signals to reach it, your position can be determined using a method called trilateration. This involves using the distances from at least three satellites to the device and determining at what point all these match.

To give your position to within a few meters, the timings have to be extremely accurate (about 20 nanoseconds) [1]. Relativistic effects mean that the clocks on the satellites tick faster than those on Earth by about 38 microseconds per day [2]. When you’re trying to get to the precision needed for accurate GPS location this is a significant difference, about 1000 times the accuracy needed. Very quickly the whole system would be completely useless.

Luckily scientists have been able to calculate the relativistic effects and correct for this, allowing you to still find your way. This is only one manner in which Einstein’s theories of Special and General Relativity affect us and it shows just how important it is to have a full understanding of their effects.

Clearly, it’s not all about black holes!

[1] Ashby, Neil, Relativity and the Global Positioning System, Physics Today, 41 [2] Will, Clifford M, Einstein’s Relativity and Everyday Life, APS Physics

Issue 12

Is ‘Crazy Cat Lady’ A Realistic Fear?

Cat Collins ponders how suicidal attraction theory in rats and cats may lead to schizophrenia, personality changes and car accidents.

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obody likes to feel like a puppet. The idea of freewill is something that is inherently connected to human nature, so the conflicting suggestion that human behaviour may be due to a number of parasites controlling your brain may disturb some. A rather extreme example of this in the animal world exists through the Lancet liver fluke, a parasite so desperate to access cattle liver it enslaves an ant, forcing it to climb blades of grass and be eaten.

Many would like to believe that this is different for humans – human brains are incredibly complicated and could resist the mechanisms of a lowly parasite. Or can they?

Domestic cats are widespread across the UK, residing in 18% of our households. It is difficult to escape them, even if you yourself are not partial to these furry felines. These cats can commonly carry Toxoplasma gondii, a parasite that functions best in the cat's’ intestine. However, if T gondii wants to spread and infect as many cats as possible, it must leave it’s comfy home in the cat and exit via the faeces to the outside world. It is exposed; it cannot reproduce; it is desperate.

"Toxoplasma gondii can cause a rat to become sexually attracted to cat urine" that happens to encounter it – take, for example, a rat. Okay, so it’s not perfect – it cannot complete its sexual life cycle – but it can take a spot in the driver’s seat at the rat’s brain.

At this point, the parasite may be defeated, although cats predate rats, their odour acts as a natural deterrent.

Yet T. gondii overcomes this, changing this innate aversion and manipulating the rat to actually become attracted to cat odour. In fact, some studies suggest that T. gondii can cause the rat to become sexually attracted to cat urine; innate fear replaced with the innate urge to mate. However, instead of the rat finding a new mate, the cat spots it...game over. Just like that, T. gondii is back in its comfortable cat home.

But what if T. gondii does not infect r nd infects an animal not likely to e eaten by a cat – say, a human? here is no evidence suggesting at T. gondii knows it’s not in the ight host and so it adopts the same mechanisms – but the human brain, complicated as it is, behaves differently. Toxoplasmosis is a buzzword for pregnant woman as infection could cause serious complications to the baby. It also can be prominent in immunocompromised individuals. However, in a regular person the infection means nothing – it seems relatively asymptomatic.

Czech scientist Jaroslav Flegr first investigated T. gondii human manipulation after becoming

convinced his personality was affected by the two cats living with his family.

Eccentric as this may seem, he produced studies that showed infected men to be more reckless and rule-breaking. He even suggested that this parasite may be leading to an increase in car accidents.

Perhaps more believable, infection with Toxoplasma gondii has found a striking

Sunflowers: Spiralling in Control What maths defines natural beauty? Chyi Chung dives into the spirals of sunflowers to find out.

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unflowers - no strangers to being muses in art - also fascinate the minds of mathematicians.

Behold, heads of tightly-packed seeds, each framed by a mane of bright yellow petals. Look again, look closer and descend into their spiralling beauty.

Alan Turing, better known for codebreaking during World War II and being subject to unjust homophobic prosecution, studied the frequent phenomenon that phyllotaxis – the geometric arrangement of seeds, leaves and petals of a plant – follows the Fibonacci series. He was not the only one. Previous attempts were made by Leonardo da Vinci and J C Schoute, a Dutch contemporary of Turing who counted the spirals of 319 sunflower heads. However, Turing’s premature death by suicide from cyanide poisoning prevented him from concluding his work.

The Fibonacci series defines each subsequent term as the sum of the two preceding it, with 0 and 1 taken as the first terms. Hence, it goes: 0, 1, 1, 2, 3, 5, 8, 13… As the series progresses, the fractions of consecutive Fibonacci numbers (2/1, 3/2, 5/3, 8/5, 13/8…) tend towards the Golden Ratio, a proportion favoured by aesthetics. Spiral phyllotaxis is easily observed in nature; a common example being sunflower heads (the looser arrangement of petals makes it more of a challenge), where seeds lie in the form of spirals, going either clockwise or anti-clockwise. The number of spirals headed in each direction is known as the parastichy number. Each sunflower head has two of these, which are often found to be adjacent Fibonacci numbers. This is where mathematics unmasks the science of the everyday.

An explanation of Fibonacci phyllotaxis stems from the biochemistry of the plant itself. In 1868, the study of meristems – plant ‘stem cells’ found at its growing tips – was conducted by German botanist Wilhelm Hofmeister, whose postulations have since been validated by electron microscopic images. Auxin, the growth hormone in plants, is quickly used up at the meristem. Hence, a primordium – newly specialised cell – that forms at the meristem tends to move outward, towards higher concentrations of auxin. Primordia also repel one another, with the greatest repulsion felt between consecutive primordia. This natural phenomenon was simulated by French physicists,

Douady and Couder, in 1992. They modelled primordia as a ferrofluid dropped into a dish of silicon oil, magnetised at its perimeter. Each new drop was observed to move from its predecessor relative to the Golden Ratio, inevitably forming Fibonacci spirals. In other words, Fibonacci spirals are the most natural form of phyllotaxis.

"80% of sunflower heads demonstrate Fibonacci phyllotaxis" In 2012, the centenary of Turing’s birth, a group of mathematicians and scientists at Manchester University launched the ‘Turing Sunflower Project’. In a bid to continue his work, it encouraged members of the public (dubbed ‘citizen scientists’) to grow sunflowers and submit sets of parastichy numbers. It took 4 years, and 3000 sunflowers, to compile the largest dataset of its kind to date: results from this summer showed that 80% of sunflower heads demonstrate Fibonacci phyllotaxis. Interestingly, some followed other geometric progressions, like the Lucas series (which has the same definition for subsequent terms but different initial terms), and some are yet to be classified. Professor Jonathan Swinton, one of the leading researchers, believes that future study lies in “creating models that take into account the full range of patterns, including the non-Fibonacci patterns”.

Such models will undoubtedly shed more light on the everyday science of sunflowers..

ARTWORK: CHYI CHUNG

Analogue Memory Recording: Turn Your DNA Into a Hard Drive Zidan Yang uses the latest advances in genome editing to unlock the secret memories of our cells.

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emory formation and storage, a notorious conundrum that human beings have been striving to understand for hundreds of years and still there is no definition universally accepted. Yet modern scientists embark on analysing memory at a digital and quantitative level. In the summer of 2016, biological engineers from MIT successfully devised an analogue memory storage machinery, which to some extent can shed new light on the interpretation of memory. This machinery is the first system that can be used to record both the duration and the intensity of events in human cells in real time. This remarkable innovation was inspired by none other than the famous genome editing system CRISPR, which consists of a DNA-cutting enzyme called Cas9 and a short guide RNA strand that directs the enzyme to a specific position of the genome to proceed i

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recognize and combat these invading viral genes when exposed to the same virus. Scientists, on the other hand, wish to adapt this system to record biological processes inside human cells.

Adroitly, instead of targeting invading genes, they manipulated the guide RNA to recognize the DNA that encodes the exact same guide RNA as itself, a so-called “self-targeting guide strand”. Directed by this self-targeting

"Scientists wish to adapt this system to record biological processes inside human cells." guide RNA, Cas9 cuts the specific DNA and generates a mutation which becomes a permanent record of this event.

More importantly, once this DNA is mutated, it will produce a new guide to the deletion of that RNA wh NA. ng as the self-targetxpressed and Cas9 is ystem could keep tation records in ore, once an exposatory process) is rememory can be generation in the y simply sequensts can determine mutations there ubsequent acbe conducted ng these ompts. This would be a po-

tent tool that enables us to monitor disease progression and developmental process from embryos to adults. In addition, just as advanced CRISPR systems do, the researchers’ engineer cells to record multiple inputs by producing different self-targeting RNA guide strands in the same cell. Ideally, each guide RNA is specifically activated when its input presents.

Rather than regarding each individual cell as a digital storage machine, scientists perceive the entire population of cells as an analogue ‘hard drive’, which massively expands the available storage of information.

“With this technology you could have different memory registers that are recording exposures to different signals, and you could see that each of those signals was received by the cell for this duration of time or at that intensity.” — Samuel Perli SM, one of the leader authors of this new study.

However, we still have no idea about what will the future hold. Any off-target effects of the DNA manipulation should be taken into consideration. Any social or ethical arguments could also affect the overall development of this technology. Are we able to record the process of memory storage and retrieval procedure in our brain using this kind of digital device? What subsequent events would this mutative accumulation result in, within our neural circuit’s plasticity? Is it possible for the National Health Service to take this technology into public health index records? All these concerns mentioned are only a starting line of the long and winding road ahead.