Synapse Science Magazine #8

SYNAPSE THE SCIENCE MAGAZINE WRITTEN BY STUDENTS FOR STUDENTS

ISSUE 8 - July 2014 - FREE

Deadly Hawaii Photographic Memory Top Ten

Frog Facts

EDITORIAL

The Synapse Team Felicity Russell Editor in Chief

Louisa Cockbill Vice President

Tom Stubbs

Secretary and Media Director

Oliver Ford

Senior Editor and Treasurer

Nick Henden

Chief Graphic Designer

Daniel Ward

Graphic Designer

Katherine MacInnes Senior Editor & Publicity Officer

Molly Hawes

Managing Editor

Toby Benham Senior Editor

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SYNA PSE Science Magazine

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elcome to the eighth issue of Synapse Science Magazine, the University of Bristol’s student science magazine. In this issue we explore predator mimicry, explain photographic memory, assess dinosaur feeding abilities and list some fun frog facts. We are a magazine written by students for students and if you would like to get involved as a writer, editor, photographer or graphic designer please join us as a member via the UBU site.

Felicity Russell Editor In Chief

Editors

Jade Low Andy Jones Rosie Hayward Eleanor Mortensson Isa Viegelmann Akifah Mia Georgina Winney Jessica Towne Lewis Le Fevre Rachel Greenwood Lexy Miles-Hobbs Rachel Burgess Lucy Haras-Gummer Hayley Ellis Daisy Dunne Daniel Stubbs Amy Newman

Deadly Hawaii

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The Mission to Reduce Emission

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A Wolf in Sheep’s Clothing

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Photographic Memory

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Solving the Challenge of Green Flying Predator Mimicry in Cats

Developing Our Understanding

What is Synthetic Biology?

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Brainwashed by Tesco

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Scandals in Nature

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CONTENTS Discover ten fascinating facts about frogs, including carnivorous tadpoles, parachuting frogs and the Wolverinelike “horror frog”.

14 Top Ten Frog Facts “...the only survivor was a hog they had kept for dinner.”

Find out why Hawaii and its volcanoes are not as gentle as we think!

16 Ornithomimid Dinosaurs Carnivores? Herbivores? Or Filter-feeders?

18 The Cost of the AntiVaccine Movement

20 Science Misconceptions 22 The Mpemba Effect

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ARTICLES

Keri McNamara

“ Look around.

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There’s no place on earth like Hawaii.

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amed for its surfing, hiking and sunshine, it’s no surprise that little elaboration was needed in this promotional statement from the Hawaiian tourist board.

The ‘island of discovery’ boasts breathtaking natural beauty and tranquil waters. Photos exist of tourists serenely sailing metres away from lava flows while the island offers volcano tours delivering tourists right into the hearts of its many volcanoes. Our trust in the chain of volcanic islands is absolute. But Kilauea, the volcano which makes up the southern most island, has deceived us - it is not as gentle as we think.

In 1790 the volcano got angry. An army was camped by Kilauea, fleeing from a recent defeat. A nearby missionary described what he saw: “in the night a terrific explosion took place throwing out flame, cinders and even heavy stones to a great distance and accompanied from above with intense lightning and heavy thunder”.

He writes that the soldiers closest to the volcano were burnt to death, and those who escaped experienced, ‘a suffocation

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sensation on their lungs’. When those who had fled returned, they found everyone dead; the only survivor was a hog they had kept for dinner.

The description is a far cry from the volcano we know today. So what happened?

Scientists have examined ash from past eruptions and the most likely scenario is a little surprising. It seems that this eruption may have been the result of a lake which formed in the crater at the top of the volcano. When the immense heat from an eruption interacts with such a lake, the water is vaporised. With so much hot steam in the system, pressure builds up which, upon release, can generate a very powerful explosion. It is thought that ground water began to seep into the superheated interior following a crater collapse from a previous eruption which lowered the volcano below the water table.

There is no evidence of a lake forming currently, and so the eight million tourists who visit the island each year are probably safe. However, the concept is still valid. No matter how much confidence we may have in the behaviour of volcanoes, they are in essence unpredictable and unstoppable forces.

The Mission to Reduce Emission Oliver Ford Solving the Challenge of Green Flying

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very year millions of us enjoy flying off on holiday, whether it is a short city break courtesy of the infamous “low-cost” carriers or something more exotic. Planes do, however, cause air pollution and are notable contributors towards greenhouse gas emissions. Some statistics argue that aviation is only responsible for 1% of world carbon dioxide emissions while research is on-going into the effects of creating this pollution high in the stratosphere (where it is claimed it does much more damage than sea-level emissions).

Alternatives to flying do exist for some cases. European travel in particular will be affected by the continual growth of highspeed train services (for example Eurostar vastly reduced demand for London-Paris flights). Trains can even save time as they can deliver passengers right to the heart of cities (saving transfers) and have far fewer “journey hassles” such as check-in and baggage-claim. Unfortunately these services in the UK are little developed beyond London and hence travel by train to the continent still takes over 6 hours.

Scientific research shows that this is beyond a “psychological” threshold at which the time convenience of flying becomes much more appealing.

Finally, technological improvements to aircraft are aiming at reducing emissions.

Much effort over the past thirty years has been spent on refining Jet engine consumption. Alternative fuels or electric propulsion could be a step forward here, however Jet fuel is exceedingly hard to beat in terms of energy density (low weight is critical in aerospace). Other approaches such as re-shaping the aircraft for more efficient aerodynamics or improving air traffic control efficiency (reducing holding times) offer uncertain savings and are complex to implement correctly.

As more people want to fly, solving the scientific problem of emissions requires more than a technical solution; a multi-faceted approach involving new technologies, tighter integration with other transport modes and promotion of alternatives to flying is needed.

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ARTICLES

A Wolf in Sheep’s Clothing Predator Mimicry in Cats

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e are all familiar with the tale of little red riding hood: a naïve girl deceived by a cunning wolf disguised in her grandmother’s clothing. Although a wolf masquerading as a frail grandmother is a hunting strategy unlikely to appear outside the realm of fairy tales, it is not as far from reality as you might think. Certain predator species have evolved the ability to mimic the calls of their prey and although this does not stretch as far as a wolf imitating a human, it has been observed in margays - a neotropical wild cat located in the northern regions of South America. The term given to this type of hunting strategy is aggressive mimicry and is defined as predators that share signals with harmless animals. Upon hearing the signal, the prey is drawn towards the predator as it interprets the sound as food, a potential mate, or even a cry for help.

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This behaviour was recently discovered by biologists from Wildlife Conservation Society Brazil, conducting research on a group of pied tamarins (a primate species).

It was during this research that they noticed a margay producing high pitched squeals nearby. These squeals bizarrely resembled the calls also made by young pied tamarins.

When the group perceived the calls, they appeared confused and eventually moved in the direction of what they anticipated to be an infant in distress. This placed them within close proximity to the margay, making a successful catch for the awaiting cat considerably more likely. This surprising discovery was, in fact, the first (and so far the only) scientifically documented account of a cat using vocal mimicry as a hunting technique.

However, tales from indigenous Amazonian tribes do contain examples of jaguars, pumas

and margays using vocal mimicry to attract prey. This suggests that the phenomenon of mimicry is more prevalent than we know as many cat species in the Amazon may also possess the ability to mimic juvenile animals as part of their hunting strategies.

Interestingly, domestic cats also display similar behaviours; a study conducted by the University of Sussex revealed that parallels exist between the frequency ranges in cat vocalisations and the cries of human babies. When owners hear these calls, they are likely to try to appease their cat by feeding or giving them attention. This suggests that cat species have evolved behaviourisms which exploit other animals’ innate need to care for their young. Although you might suddenly feel less affectionate towards your cat, you can’t help but marvel at the incredibly manipulative and advanced predatory behaviour that has evolved in these cunning felines. It also raises the question as to whether other cat species such as African or Asian varieties also possess abilities of mimicry, as seen in their South American and domestic counterparts. Further research in this field is needed in order to shed light on whether mimicry is a common occurrence in margays, how this behaviour initially developed and why it seems to be particularly prevalent in cat species- so watch this space!

Although a wolf masquerading as a frail grandmother is a hunting strategy unlikely to appear outside the realm of fairy tales, it is not as far from reality as you might think.

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Bethany Rielly

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ARTICLES

Photographic Memory Developing Our Understanding

Connor O’Malley

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hen exam season rears its ugly head we all wish we had that gift: the ability to reach into the deepest, darkest parts of our minds and pull out the desired chunk of information, to traverse our neurons and scrutinise each of our memories. Photographic – or as it’s also known eidetic – memory seems simply too good to be true. It seems astonishing then that we’re constantly hearing of people who seem to have this innate gift.

Could it really be that some people can remember everything they see?

Not according to cognitive scientist Marvin Minsky, who claims “...we often hear

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about people with ‘photographic memories’ that enable them to quickly memorize all the fine details of a complicated picture or a page of text in a few seconds. So far as I can tell, all of these tales are unfounded myths, and only professional magicians or charlatans can produce such demonstrations.”

Damning words indeed, but Minsky’s is not the only dissenting voice. As far back as 1964, Ralph and Ruth Haber, in their paper testing elementary school children for ‘eidetic imagery’ wrote “No serious doubts were raised about the validity of eidetic imagery as a phenomenon, even though the methodology

of assessment has been both poorly described and poorly executed, eidetic imagery just ceased to excite scientists.” So why exactly has research into eidetic memory been left behind?

To answer this, first we must understand exactly how eidetic memory differs from normal memory. If it were just a simple ‘upgrade’, eidetic memory would be a much more easily-defined concept. As it stands however, we view eidetic memory as being completely separate from normal memory.

The method by which we conventionally store information – the basis of our memory – is a process called ‘long-term potentiation’ or LTP. This involves the strengthening of two neurons when they are, over a period of time, active together. Activity in one neuron will tend to induce activity in another neuron, forming our current picture of long-term memory.

The problem regarding eidetic memory is that LTP requires repeated usage in order to strengthen these synaptic activities, involving many rounds of stimulation before actively remembering something in the conventional manner. The ability to look at something once and then retain a picture-perfect memory cannot be based in LTP. Supporting the theory of eidetic memory being separate from normal memory are studies of children capable of recalling images at the eidetic level. In the previously mentioned experiment by Haber and Haber, “the prevalence of eidetic imagery... was quite low - about 8%. However, the 12 [subjects] who were classified as eidetic were not merely the end of a continuous distribution, but rather were children who showed qualitatively different behaviour on this simple perceptual task. Therefore, eidetic imagery does exist as a verifiable, identifiable characteristic in children.” Although 8% seems small, compare this with the incredible rarity of the phenomenon in adults. Not only does eidetic

memory differ fundamentally from normal memory, some of us also lose the ability as we move into adulthood.

One understanding of this is by thinking of short-term sensory memory, as opposed to long-term verbal memory, being the precursor to eidetic memory. Being unable to express their thoughts in a discernible manner, children rely on sensory memory to understand the world around them – it’s therefore unsurprising that they possess an ability to recall all that their senses tell them about an object or image. As they grow up and begin verbal communication, a new form of long-term memory emerges based on the repeated usage of certain words, phrases and ideas. Long-term potentiation is developed and the ability for total recall after one stimulus is somehow lost.

Does this mean that eidetic memory in adults does not exist? Certainly not.

There have been examples of people with extraordinary feats of memory occurring all over the world – to simply dismiss these would be folly. It’s clear that in certain people memories are collected and stored in a completely novel way to the conventional means – whether it be a case of nature or nurture, an actual neurological phenomenon or a unique environment, there’s more to a good memory than meets the eye.

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ARTICLES

E T SYN H TIC BIOLOGY

Rachel Argo

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ynthetic biology is a young and exciting field of science encompassing the work of researchers from a variety of disciplines including engineering, computer science, biology and chemistry. ­Essentially, synthetic biology aims to investigate and manipulate biological systems to perform new functions such as producing fuels or vaccines.

The possible outcomes of research in this field are therefore diverse and could include new approaches to medicines and power.

The UK government has identified synthetic biology as one of the ‘eight great technologies’ which will propel the UK to future growth and help it stay ahead in the global race, due to its potential to deliver new applications and economic benefit to society.

Therefore funding and research initiatives in this area of science are growing.

The University of Bristol has recently announced an award totaling £13.6 million from the Biotechnology and Biological Sciences Research Council (BBSRC) and the Engineering and Physical Sciences Research Council (EPSRC) to form a research

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centre in synthetic biology. The new centre ‘BrisSynBio’ will bring together scientists from the faculties of Science, Medical and Veterinary Sciences and Engineering. This grant follows the announcement of the establishment of the Centre for Doctoral Training in Synthetic Biology; a collaboration between Bristol, Warwick and Oxford which offers a 4 year PhD programme for training in this field. Bristol is also part of SynbiCITE, an Innovation and Knowledge Centre led by Imperial College London, which aims to collaborate synthetic biology research between industry and academia.

The new centre’s aims include developing novel antibiotics, building cells from scratch and re-engineering of bacteria to perform tasks such as breaking down plastics and pollutants – exciting times for BrisSynBio.

A synthetic genome was transplanted into this bacterium such that it produces a blue compound.

Image: Science/AAAS

BRAINWASHED By

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TESCO

ver come home from the supermarket with a lot more than you intended to buy? Like most students I am a sucker for a deal and often get persuaded to spend a lot more than necessary when that bright yellow “REDUCED” sticker stares at me from the shelves.

Researchers at Bangor University are currently using functional brain imaging techniques to investigate how shoppers respond to special offers and what triggers their p ­ urchasing decisions. Volunteers will perform a virtual grocery shopping task whilst having their brains scanned to monitor changes in blood flow within the brain.

Previous research has demonstrated that the blood oxygen level dependent (BOLD) signal, an indirect measure of activity, is increased in different areas of the brain during different stages of the shopping task. When desirable items were viewed, heightened activity was evident in the nucleus accumbens – a structure associated with reward-seeking and addiction. When an item was priced lower than expected medial prefrontal cortex activity – often assigned to attention - was elevated whereas item rejection increased activity in the insula which is an area related to pain.

Psychologists in Bangor hypothesise that after 23 minutes of shopping, logical decision-making will gradually cease and rash choices will be made due to a transition

of dominating brain activity from logical processing regions to emotional centres.

The results of these studies may lead to a better understanding of the brain activity necessary for decision-making and no doubt retailers will benefit by altering marketing strategies to increase profit.

But is this research really worth the price?

MRI scanners cost over a million pounds but when used for life-saving diagnosis or treatment, such as in stroke patients, this expense is more than justifiable. Can the same be said for exploring shopping habits?

It is a nasty thought that NHS patients requiring an MRI scan for medical purposes can be on waiting lists for months when this valuable clinical tool is easily accessible for research which will inevitably be exploited to manipulate customers into making unnecessary purchases.

Don’t supermarkets control enough without adding our minds to the list?

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ARTICLES

Scandals in nature

Katherine MacInnes

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he most cited and, arguably, most famous scientific journal is the giant that is Nature. Its origins lie in London and the words of William Wordsworth: “To the solid ground of nature, trusts the mind that builds for aye.” It was first published in 1869 with editor Norman Lockyer, an Imperial College professor. Since then Nature has become ‘sexy science’ and you must have a reputation to get there, often making many people in the scientific world feel that you need to know the right people.

Exclusivity in ­Nature is nothing new: the original writers tended to be from the ‘X club’, which makes me think of Victorian scientists sitting about taking snuff and discussing science whilst slightly tipsy or, alternatively, a rather silly-looking group of superheroes with tweedy Victorian capes and monocles. Actually, they were a dining club of scientists, two of which, Hooker and Huxley, co-founded Nature.

The Nature Publishing Group is expanding and now encompasses many off-shoot journals, including Nature Nanotechnology, as well as more accessible news, comments

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and podcasts. Part of the original Nature objective was “to place before the general public the grand results of scientific work and scientific discovery; and to urge the claims of science to move to a more general recognition in education and in daily life.”

By publishing these more accessible articles Nature attempts to achieve this aim, but it remains likely that the majority of the readership are scientists. In addition, like many journals, Nature has not escaped criticism on its selection and publishing practices.

Uniquely for a scientific journal, Nature has endorsed American presidential candidates, with Barack Obama being the first it supported back in 2008. Again in 2012 an editorial showed Nature’s support for the Democrats: ”The past positions of the candidates and the records of their own political parties make it clear that Obama and the Democrats offer important advantages for science over Romney and the Republicans.” Many people perhaps feel that science should not get involved with politics, but its involvement is inevitable. Scientists also have to weather the unstable financial climate, so funding for research is difficult to find and many

feel that money is not being well spent on research that could potentially prove invaluable for health and technological advances long-term. During the last presidential race Romney stated: “I’m not in this race to slow the rise of the oceans or to heal the planet”, which makes it unsurprising that Nature would unashamedly side with his opponents.

Is [the research] “good, or merely

assumed to be good because of the prolific name preceding it?

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Nature has not escaped the furore over falsified data, most notably in the case of Jan Hendrik Schön, who appeared to make several breakthroughs in his work with semiconductors until he was accused of fraud. Another scientist in the field had spotted identical noise in separate graphs, leading to allegations of using mathematical functions to generate the data. This turned out to be true and Schön’s doctorate was later revoked. This scandal led to discussion of whether or not the peer review system used by most journals should be stricter. In most cases, papers are peer-reviewed by academics in the same field, meaning that it is not uncommon for academics to know the authors whose papers they are reviewing. This obviously opens up the review system to criticism due to bias, however it is difficult to improve the system when reviewers must have expert knowledge on the topic. Famously, Watson and Crick’s

landmark 1953 Nature paper outlining their findings on the structure of DNA was not sent out for peer review at all. The editor at the time, John Maddox, later said: “the Crick and Watson paper could not have been refereed: its correctness is self-evident”, despite Watson expressing concerns about their model before and after publication.

The relationship between publication and science is a difficult one. The necessity of publication pressures scientists and can result in cutting corners. The journal must verify the validity of the data because they are ultimately seen to endorse the science that they publish, but unfortunately many review systems are flawed. These systems are especially critical for a big journal such as Nature: science published here reaches the media quickest of all and its size and fame catches the attention of the public and politicians alike.

It is admirable that Nature attempts to bridge the gap between scientists and nonscientists but it can feel like bigger journals do not make an attempt to dampen the sense of elitism in a community that should be founded exclusively on good science.

Articles published in Nature are retracted just as often as in lesser journals and cannot be counted as perfect science purely due to reputation. The question that is inextricably linked to high impact factor journals, such as Nature, is whether the research in them is good, or merely assumed to be good because of the prolific name preceding it.

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ARTICLES To find the world’s largest frog, look to Africa to see the goliath frog (Canraua goliath). This beastly amphibian can weigh up to 3.8 kg and reach a body size of 40cm from its snout to its vent. This frog mostly feeds on worms and large insects, such as dragonflies, but has been known to be capable of taking out small snakes and even baby crocodiles!

In contrast, you can find the world’s tiniest frogs in New Guinea.

The Paedophryne dekot and Paedophryne verrucosa were only discovered in 2011 and are both a mere 8-9 mm long. To put that into perspective, a pair of them could sit on the head of a drawing pin!

The tiny Paedophryne dekot magnified 60 times.

9 mm Lots of frogs display very strange and often completely unique behaviours when attempting to attract a mate. The red-eyed tree frog (Agalychnis callidryas) of the Central American rainforests is the first treeliving animal known to use vibrations as a form of communication. The frog will call to attract females but warn off rival males by vibrating the branch they are on. A pseudo ‘wrestling match’ ensues, the male that vibrates most vigorously and for the longest tends to win.

Ever thought a frog could resemble your favourite super hero?

Cameroon’s screeching frogs (Family: Arthroleptidae), have modified hands that can be likened to the comicbook character Wolverine. Sharp, clawlike bones burst through the skin of their fingertips when they feel threatened. The claws are also useful for finding grip when scrambling through slippery surfaces.

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Despite the seemingly innocuous small size of most frogs, they can be seriously loud! The Puerto Rican male common coquí frog (Eleutherodactylus coqui) is a nocturnal singer that can blast out 100 decibels from half a metre away, making it one of the world’s loudest amphibians. If one male invades another’s

The Trichobatrachus robustus or “horror frog” has retractable ‘claws’.

territory, the two males engage in a ‘singing duel’. The two frogs will spar until one gives up and accepts defeat.

The vast individuality of frog species observed on our planet is made possible by their ingenious ability to adapt to extreme environments.

In Australia, the green tree frog (Litoria caerulea) comes out at night to sit in temperatures so cold they can barely move. The reason for this is to obtain water when rainfall hits rock bottom. The chilly frogs hop back into their warm dens in tree hollows and condensation forms all over their skin.

Resourcefully, the frogs absorb the water through their skin to quench their thirst.

Frogs can be great escape artists.

The horned frog (Ceratophrys ornata) of Argentina deploys a unique tactic to avoid tadpole cannibalism. Tadpoles of the species are ferociously carnivorous and will eat the tadpoles of other species. To prevent tadpoles of the same species eating each other, the tadpoles will let out a loud metallic scream underwater to let others know they are being attacked by their own species.

An impressive feature common to all frogs is their gigantic fast-working tongue. On average, a frog’s tongue is about a third of the frog’s body length and can shoot out to catch prey at fifteenhundredths of a second. The tongue works like a catapult. When ­resting, the muscles lie flaccid but when prey is spotted fibres that run down the tongue stiffen, allowing the tongue to become rigid. Muscles at the base of tongue rapidly contract, propelling it around and then out the mouth.

The tongue strikes the prey and then other muscles pull the prey into the mouth – all within a fraction of a second!

To add to their attributes, frogs are impossibly impressive jumpers. The distance covered by a frog’s leap, up to 5 times its body length, is theoretically impossible as it requires more power than its muscles should have. The frog overcomes this by becoming a living catapult. The frog’s leg muscles contract long before the frog leaps, which loads energy into its ankle tendons. This pent up energy is released when the frog makes a leap, allowing it to reach otherwise unmanageable distances. A superior jumper is the Australian rocket frog (Litoria nasuta), which can make leaps of up to 2 metres! by

Daisy Dunne

The Malabar flying frog can make gliding jumps of 9–12 metres. That’s almost 115 times its length!

Finally, it should be known that some frogs can fly! Wallace’s flying frog (Rhacophorus nigropalmatus) utilises its webbed toes to glide from tree to tree. The webbing between its toes stretches out and to act as miniature parachutes to allow safe airborne travel.

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ARTICLES

ORN ITHOMIMID DI NOSAURS

CARNIVORES? HERBIVORES? OR FILTER-FEEDERS? Sebastian Sonesten

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he bird-mimic dinosaurs Ornithomimids are a peculiar group of light, fast dinosaurs, with long arms and large eyes. Deeply nested within the carnivore group, the theropods, one would expect the ornithomimids to be keen predators, but several characteristics suggest they would not have been very good hunters after all.

Living in the Cretaceous period, they were close relatives of Tyrannosaurus rex and the smaller, yet perhaps even more deadly dromaeosaurids, the sickle-clawed dinosaurs, such as Velociraptor and Deinonychus.

Perhaps the most distinguishing feature of the Ornithomimidae is a toothless beak, similar to that of birds. What puzzles scientists is that a toothless beak is a typical trait of herbivores or omnivores. Many herbivorous dinosaurs evolved a toothless beak to scoop plant material into their mouths.

However, what is even more peculiar is that some ornithomimids lost all their teeth. An example is the familiar Gallimimus. But why did the ornithomimids do it?

A clue came up when scientists discovered stones swallowed on purpose to help grind food in the stomach, known as gastroliths. Gastroliths are typical tools used by herbivorous dinosaurs to process tough, fibrous plant parts. Maybe the ornithomimids were herbivores with

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no need for meat cutting teeth?

This could also help explain why their long arms were slender and weak, probably not useful for holding struggling prey, but maybe for pulling down tree branches. Their huge eyes suggested excellent eyesight, but the eye sockets were facing outwards, so they lacked the ability to judge distances, which is important for an effective predator.

Instead, they would have had a broad field of view better suited for keeping eyes out for predators. Predators tend to have a good sense of smell for detecting prey however brain scans show that ornithomimids likely had a poor sense of smell similar to a planteater.

However, there was something that did not make sense. The ornithomimid skull was lightly built, probably equipped with weak jaw muscles, and akinetic – the jaws could not move from side to side like that of herbivores. Although this was first taken as a sign of them being poor killers, it does not make them good herbivores either.

Coupled with the fact that most of them had no teeth, the Fig 1: An artist’s impression of Ornithomimus, the type genus of Ornithomimidae. Image copyright © 2014 rareresource.com

Fig 2: The toothless skull of Gallimimus.

Image copyright © P. Makovicky et al. 2004.

ornithomimids would have had to rely on their gastroliths, a small stomach and intestines alone to digest plant food.

An alternative idea was that they may have fed on smaller animals, such as lizards, amphibians, gastropods (snails, slugs), and insects. However, their poor depth perception would have made it difficult to catch small, typically fast-moving prey.

Perplexed, it seems scientists have now settled for ‘omnivore’. It is a tempting thought, not only because it is a convenient compromise, but because it seems the ornithomimids may have been able to feed on both plants and tiny animals, though not well enough on either to be exclusive.

However, an intriguing suggestion remains, one that it seems

has not gained much attention – which is surprising, as it is quite radical! The idea is that the ornithomimids may have been filter-feeders, feeding on small food particles suspended in water.

Not many land-based vertebrates filter feed, but the ornithomimids are mostly found near lakes or rivers, suggesting a connection.

Moreover, it may be that one ornithomimid, Pelecanimimus, had miniature teeth concentrated in the front of its mouth which may have been used as a primitive filter apparatus. Gallimimus may also have had hair-like fibres along the edge of its toothless beak to filter small particles.

Filter-feeding does not require toothed jaws capable of transverse motion. Smell is neither particularly useful for filter-feeders.

The broad field of vision would have kept it alert from danger while sinking its beak into the water. The weak arms might have been used to stir up sediment from the bottom to be filtered for food. However if they were filter feeders they would not need gastroliths so even this theory does not answer everything.

The precise diet of ornithomimids remains a mystery, and the apparent variety within the group even suggests that different species may have eaten different things.

Fig 3: A model of the skull of Pelecanimimus, with hundreds of miniature teeth concentrated toward the front of the mouth, possibly functioning as a rudimentary filtering device.

Image copyright © 2012 www.eofauna.com

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ARTICLES

Rob Cooper

D

uring the 20th century an estimated 300-500 million people died from Smallpox. From 1967, 2 million people died each year. That’s 5479 a day, 228 an hour, 3 people every minute.

Today smallpox is the only disease that has been successfully eradicated by modern medicine thanks to a vaccination developed in December 1979. Since then there have been no deaths from smallpox and it no longer exists in the wild. At the rate it was killing, that is 68 million lives that have been saved by this one vaccine.

So why was the smallpox vaccine so successful? The answer lies in the term ‘herd immunity’.

Herd immunity relies on a large enough proportion of a population being immune to a disease so that it is unable to spread to those that have not yet developed immunity. This is because the disease moves through the population by travelling between hosts and if it cannot infect those who are immune it cannot spread and will eventually die out. This strategy means that as long as the majority of the population are vaccinated (varying from 83% for smallpox up to 94% for mea-

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sles) then those who cannot be vaccinated, such as the very young, those allergic to the vaccine or those with compromising conditions such as AIDS, are safe from these diseases. Clearly a significant proportion of the world population was vaccinated against smallpox, but why are other easily curable diseases still causing deaths globally?

In 1998 Andrew Wakefield published a paper claiming to have identified a link between the MMR vaccine and autism in children. No scientist could match his findings and he was later found to have been paid over £400,000 by lawyers to undermine the vaccine. His data was found to be fabricated and his medical licence was justifiably revoked but despite the complete rejection of his findings by the scientific community his toxic legacy lives on.

The CDC (Centres for Disease Control and Prevention) estimates that globally 164,000 people will die from measles and 195,000 from whooping cough per year.

Most of these deaths are in impoverished regions where vaccines are hard to come by but recently several states in the USA have reported a drastic increase in whooping cough.

In the UK whooping cough cases have increased from 494 in 2008 to 740 in 2011

and 8059 in 2012. To put it simply, outbreaks of measles, mumps, rubella, whooping cough or polio should not be occurring in the UK or US at all, and certainly not in the numbers they are. Is the anti-vaccination movement the only problem? No, poor hygiene and other factors play a part but the role of the movement is undeniable.

If children are not vaccinated then the chances of them contracting whooping cough is 23 times greater and measles 35 times greater. However, if this threat to your children is not enough motivation, it also endangers anyone who is unable to have the vaccination through choice or due to medical conditions. Herd immunity means that individuals with allergies to the vaccine, young children who cannot be vaccinated yet and those with immunological conditions such as AIDS are at risk from potentially lethal diseases if you choose not to be vaccinated.

But what about the potential side effects of vaccines? The vast majority of side effects have no long term impact and those that do are rare. For example, the side effects of the MMR vaccine include fever in 1/6 people, a rash in 1/20 people, seizure in 1/3000 (staring or jerking, no long term effects) and severe allergic reaction in 1/1,000,000 people. In fact 0.6-1% of people have a peanut allergy, this means you are 6000-10,000 times more likely to be allergic to peanuts than the MMR vaccine. Furthermore there has never been

a definitive link between the MMR vaccine and death.

Compare this to alcohol and tobacco which rack up 40,000 and 114,000 deaths per year respectively and the vaccine looks harmless. Undoubtedly some would point to infants with autism and claim that the MMR vaccine is responsible. This claim is outdated, unsupported by any evidence and it is now clear that the vaccine is not to blame Since 2007 there have been 127,447 cases of preventable diseases in the USA and 1324 deaths. By not vaccinating your children you are contributing to this ever growing body count. Current figures suggest that as time passes the situation is getting worse. Vaccines are one of the greatest achievements in modern science and it is due time that people were reminded just how critical they are.

A white blood cell (yellow), engulfing anthrax bacteria (orange).

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ARTICLES

Alcoholic beverages warm you up.

Alcohol can cause dilation of blood vessels at the surface of the skin creating a warm sensation, however, this can also often leave you with a lower core body temperature as a result.

Alcohol kills brain cells.

Alcohol does not directly kill brain cells but this can be an indirect effect of long term heavy alcohol consumption.

Mis Scie con nce cept ions

Fish have a 3 second memory.

Actually fish can remember for a few months.

Plymouth researchers have even shown that fish can be trained to push a lever at a certain time during the day to retrieve food.

The most venomous spider in the world is the Daddy longlegs but they cannot bite.

The main confusion here is due to multiple creatures being referred to as daddy longlegs.

Opilionids such as harvestmen are often referred to as daddy longlegs, they have eight legs but are not spiders. Most do not have venom glands or fangs. Crane flys are also often mistaken for daddy longlegs spiders but are insects. However daddy longleg spiders which are Pholcids do have venom and fangs but rarely bite humans. They also contain such a small concentration of venom that when they do bite this has been reported to feel like a small burning sensation.

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Fel icit yR uss

ell

If you cut an earthworm in half it will form two worms.

Actually only the section with the head will survive depending on where the worm is dissected.

You only use 10% of your brain.

Although all brain neurons do not concurrently fire, over the course of a day the majority of neurons are active and we use almost 100%. This may have emerged from the psychologist William James in the early 20th Century who often referred to humans using only a small percent of their potential which over the years has been altered to brain percentage.

Left brain vs Right brain dominant.

It is a common theory that methodical and analytical thinkers are right brain dominant whereas artistic people tend to be left brain dominant. Although certain brain hemispheres are more important for speech and language there is no strong evidence that people preferentially use their left or right brain.

Sunflowers track the sun.

Numerous people believe that the heads of Sunflowers (Helianthus annuus) can track the sun across the sky. Actually most sunflowers stay in a fixed position usually facing east, although the very immature buds do occasionally track the sun before they flower.

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ARTICLES

The

Mpemba Effect

L

ast year, Nikola Bregovic of Croatia won a competition created by the Royal Society of Chemistry to provide the best explanation to date for the Mpemba effect: why hot water freezes faster than cold water. The discovery was first made by Erasto Mpemba of Tanzania, a student at the time, when freezing ice cream. It was at the end of a guest lecture by British physicist Denis Osborne that Mpemba asked, “if you take two similar containers with equal volumes of water, one at 35 °C and the other at 100 °C, and put them into a freezer, the one that started at 100°C freezes first. Why?” Osborne then experimented himself and confirmed the findings. Although Mpemba was not taken seriously at first, together with Osborne they wrote a paper on the effect that was published in 1969.

Bregovic is a PhD student at the University of Zagreb, studying supramolecular chemistry, who was notified of the competition by a friend. He supported a previous statement by J.D. Brownridge, “hot water will freeze before cooler water only when the cooler water supercools, and then, only if the nucleation temperature of the cooler water is several degrees lower than that of the hot water. Heating water may lower, raise or not change the spontaneous freezing temperature”. Bregovic then added, “the effect of convection, which enhances the probability of warmer water freezing first should be emphasized in order to express a more complete explanation of the effect”.

A similar effect had already been noted down in history by famous academics ­including Aristotle, Descartes and Francis

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­ acon. Although the effect appears contrary B to what thermodynamics permits, possible reasons had included evaporation, convection, frost, supercooling, solutes, thermal conductivity and latent heat of condensation. No single effect is conclusive and it may depend on the experimental set up.

New Scientist recommends starting the experiment with containers at 35°C and 5°C to maximize the effect. This is not the only strange property of water, for example the Leidenfrost effect observes that lower temperature boilers can sometimes vaporise water faster than higher temperature boilers.

Water also has a higher entropy of vaporisation than most liquids due to the low entropy associated with liquid water, resulting from hydrogen bonding. Another unexpected property is that water is most dense at 4 °C. For intuitive reasons, warmer water is less dense, but below this temperature the density decreases due to the arrangement of the molecules in the frozen state – once again the result of hydrogen bonding.

What we can take from all this is that water is a truly special molecule – one that we need and one that we should appreciate.

If it weren’t for these peculiar properties, then we would not be able to live. Although the exact reason for the Mpemba effect is still unknown and will probably remain unknown, it is satisfying to have some further clarity.

Toby Benham

‘The School of Biochemistry at Bristol celebrates its 50th anniversary in 2014. Biochemistry is a scientific discipline that seeks to explain and understand life at the molecular level. It is a field that has grown enormously over the past half century and is now integral to virtually all biological and medical research. Over the past fifty years Bristol Biochemistry has played a central role in understanding key life processes such as how cells are powered, why diabetes develops and how information in DNA is translated into life itself.

Explaining the complexities of living molecular systems is frequently challenging but core to our teaching programmes. Bristol Biochemistry applauds the success of Bristol students in producing informative and insightful publications such as Synapse. We are very pleased to have the opportunity to sponsor this volume as part of our 50th anniversary celebrations.’

Prof. Leo Brady, Head of School

The central nervous system of a grasshopper embryo.

Original image by BSCB competition winner Dr. Anna Franz from Bristol’s School of Biochemistry.

The protein structures of most of the key glycolytic enzymes structures fundamental to understanding organic energy derivation - were measured in Bristol, including human muscle aldolase (top) and glucose-6-phosphate isomerase (bottom).

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