Bang! Hilary 2017

Bang!

Hilary 2017

Marcus du Sautoy Brain imaging Cell communication The digital world

The Communication Issue

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CONTENTS

THE Bang! TEAM Editors in Chief Josephine Pepper Kirstin Latimer

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Editorial

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News

6

The Paris Climate Agreement

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What’s on in Oxford

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Small talk

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CLARITY

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The future through fibre

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OMGs and emojis

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Interview with Professor Marcus du Sautoy

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RNAgents

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Monkey see, monkey do

Deputy Editors Ellen Pasternack (Print) Mantas Krisciunas (News and Web) Ray Williams (Media and Broadcasting) Creative Director Edward Huang

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Interview with Sally Le Page

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A bit of a fix

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Secret supersocieties

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It’s a small world

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The cocktail party problem

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Book reviews

Sub-editorial Team Thomas Player Claire Ramsey Rachel Kealy Jiaxen Lau Brianna Stewart Calum Stephenson Elena Zanchini di Castiglionchio Rosemary Chamberlain Artists Martha Glover Kailin Sun Chloë Jacklin Sophia Malandraki-Miller Lucy Allison Denise Lai Gulnar Mimaroglu Asiyla Radwan Business Team Malak Khahil Bethan Broad

ERRATA

OSPL staff Chairman Daniel Kodsi Managing Director Rebecca Iles Company Secretary Tom Hall

Finance Director Katie Birnie Business Manager Rebecca Iles Directors Sophie Aldred, Mack Grenfell, Tom Metcalf, Steven Spisto

Hannah Cornwall wrote ‘Spotlight on Zika’ Zoe Catchpole wrote ‘Calling time on the obesity epidemic’ Elena Zanchini di Castiglioncho wrote ‘PharMANcology’

Cover art by Edward Huang

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MEANWHILE, AT EDITORIAL HQ...

Communication issues are a fact of life, but in a world where soundbites and tweets speak louder than fact, transparent communication has never been more important. The interface between the real and the digital is blurring and it’s impossible to ignore the influence this has on politics (page 6), language (‘OMGs and EDITORIAL emojis’, page 12) and scientific developments (‘A bit of a fix’, page 23).

From the fundamental signalling mechanisms of bacteria (page 8), through insect supersocieties (page 24), to our close primate relatives (page 18) and our own social networks (page 26), this edition of Bang! explores the full spectrum of biological complexity. It has been fantastic to be able to present a more diverse representation of the science subjects in this issue, with articles covering genetics, neuroscience, and physics.

into the public domain was a standout highlight in the production of this issue. We even strayed into the realm of the philosophical: perhaps there are truths that science will never be able to uncover.

In the meantime, ever wondered why you share mutual friends with every Oxford student? Or how you can tune in to one juicy story above the background chatter of a formal hall? Look no further!

Enjoy this Hilary Term issue of Bang!.

Editors-in-Chief Josephine Pepper & Kirstin Latimer

We also hear from the communicators themselves. Speaking to Marcus du Sautoy (page 14) about the universal language of maths and how he is bringing the excitement of science

Art by Edward Huang

News in focus: A global effort to understand mysterious space blasts For the first time, we have been able to uncover the home of an elusive cosmic signal known as a fast radio burst (FRB).

These bursts, lasting only thousandths of a second, have been notoriously difficult to pin down, but a source that emits FRBs repeatedly has finally been found, giving scientists a chance to study these signals in more detail.

A dwarf galaxy was found at the location of their source, described by Shriharsh Tendulkar, an astronomer at McGill University, as “puny”. Although his team has pinpointed the source of these emissions, questions remain as to what exactly it is in the dwarf galaxy that is causing them. Some had previously proposed that FRBs come from cataclysmic stellar events that destroy the source of the radio burst. The fact that this signal, known as FRB 121102, repeats itself would suggest that this is not the case, but it is possible that FRB 121102 is not typical—after all, no other FRBs have been observed to repeat. “What we learn from these papers may not be applicable to FRBs more broadly,” argues Peter Williams of the Harvard-Smithsonian Center for Astrophysics.

First spotted in 2007 by the Parkes Observatory in New South Wales, Australia, FRBs have been problematic for physicists because of their infrequent and erratic appearances in telescope data. To date, only 18 distinct FRBs have been seen, but the first six of these were seen only by the Parkes radio telescope, leading some scientists to suggest these signals were nothing more than artefacts of the telescope itself. This changed in 2012 with the first observation of FRB 121102 at the Arecibo Observatory in Puerto Rico. Since then, researchers have also uncovered bursts in old data from other telescopes.

FRB 121102’s repeating radio signal was uncovered by PhD student Paul Scholz at McGill University, who was working through the Arecibo data. His team found ten blasts that seemed to have

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the same characteristics as the lone FRB 121102 signal. However, these blasts were not enough to associate the location of the source with anything in particular, such as a specific galaxy. To do this, the team employed a collection of radio telescopes situated all over the world.

Shami Chatterjee at Cornell University spearheaded a campaign using the Karl G Jansky Very Large Array (VLA) to gather data they could compare with measurements from Arecibo. Meanwhile, Benito Marcote of the Joint Institute for VLBI ERIC led the search for FRBs using the European VLBI Network (EVN).

Over the course of several months the joint team set their network of telescopes on the right area of the sky and looked for the distinctive signals. The Arecibo and EVN observations simultaneously detected four bursts from FRB121102 and in just over 83 hours of VLA observations nine bursts were counted, one of which was also found by Arecibo.

This allowed the scientists to locate the source of the signals a thousand times more precisely than they could with the single dish at the Arecibo Observatory.

Now the remaining challenge was to use data from other telescopes to study the source. A persistent radio signal was also coming from the same location as FRB 121102 which prompted them to look at it in other wavelengths.

It was data from the Keck telescope taken in 2014 that turned up trumps: a bright spot in exactly the same position.

Dr Tendulkar then led a set of observations using the Gemini North telescope at Mauna Kea in Hawaii to investigate this further. The additional data allowed them to pin down and study the dwarf galaxy that was found to be shooting

these bursts and to investigate their enigmatic source.

Two hypotheses have emerged so far.

The source of the bursts could be an active galactic nucleus—a supermassive black hole surrounded by a huge disk of gas that spits out energy and radio waves as it is drawn in. Or it may be a supernova—a cloud of searing hot gas and dust being energized by a young neutron star, dating the source of FRB 121102 to between 100 and 1000 years old.

Although evidence is mounting, the source still remains a mystery and Dr Chatterjee is adamant that their job is not over yet. “Our highest priority for the future is to find one more FRB that repeats,” he says. “Right now we are arguing from a sample of one, which is always a dangerous argument to be making.” A strong hope for the future comes from the long-awaited CHIME radio telescope array, which may have the potential to find thousands of FRBs, giving scientists a chance to better understand these elusive blasts from space.

Written by Kathryn Boast Art by Edward Huang

News in brief: Big data for New quantum digital diagnosis computer

A titanic crack

iCarbonX, a Hong Kong startup founded in 2015 by Jun Wang, recently announced detailed plans to use artificial intelligence (AI) to develop a healthcare app that would crunch unheard-of quantities of data on every one of its users and deliver predictions for developing various diseases. Allied with a host of other companies that are manufacturing various technologies to easily monitor traces of various particles in human blood and other tissue, iCarbonX plans to use cutting edge AI algorithms to process this information and provide quick diagnostics. The app, called Meum, will also use extraneous factors like air pollution, diet, and fitness levels of its users in its predictive algorithm.

D-Wave, the Canadian company known as the first in the world to commercialise quantum computing, has recently released its latest model, the 2000Q. 2000Q is named after the approximate number of qubits, units of quantum information, on which it operates. With double the qubits of its predecessor, the machine is still controversial as scientists have yet to reach a unanimous decision on whether D-Wave’s framework will ever be able to surpass the speed of classical computers. Currently the 2000Q is able to perform well on solving optimization problems, but not much else. Perhaps surprisingly, therefore, one 2000Q is already being employed to fight cybercrime by Temporal Defense Systems, a US-based cybersecurity firm.

A crack in the Larsen C ice shelf, a massive formation on the northermost part of the Antarctic mainland, is set to create an iceberg the size of Norfolk by the end of March. Scientists have been monitoring the formation of the crack since it first started developing two years ago, but this summer the process considerably sped up and shows no signs of stopping, stoking fears that the complete breakup of the ice shelf is in sight. Researchers who have in the past camped on Larsen C in order to carry out seismology experiments have not done so this season due to fears that the ice could crack at any moment.

Countdown to catastrophe

The Falcon has landed

Synthetic bacterial DNA

The Doomsday Clock, a symbolic gauge created in 1947 by the members of The Bulletin of the Atomic Scientists, inched half a minute forward during the first week of Donald Trump’s presidency and now sits at two and a half minutes to midnight. First designed to reflect the looming threat of nuclear war during the Cold War, the clock represents the likelihood of global catastrophe at any given time and, since 2007, it has taken the danger of accelerating global warming into account as well. This is the closest the clock has ever come to midnight since 1953, when the successive tests of thermonuclear weapons by the United States and the Soviet Union prompted its minute hand to hang only two ticks to 12.

After seeing their Falcon 9 rocket explode during an engine test last September, engineers at SpaceX were relieved after the same model managed to successfully place ten communications satellites into orbit and return safely down to Earth in January. The failed September test had not only resulted in the destruction of the rocket itself, but also consumed the communications device the rocket was carrying, which was supposed to contribute to Facebook’s Internet.org project, improving internet access in less developed countries. Since a reliance on disposable rockets is currently the biggest bottleneck in making space travel more affordable, the continued success of SpaceX could open up a whole new era of cheaper spaceflight.

Scientists from the Scripps Research Institute in La Jolla, California have incorporated an additional base pair into the DNA of bacteria. This is the first time that the modified bacteria survived and kept reproducing with the additional nucleotides fixed in their DNA. Even though the cells were still unable to produce the nucleotides themselves, having to be fed a constant supply by the researchers, this represents a big step towards making completely novel forms of life.

Written by Mantas Krisciunas Art by Edward Huang

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The Paris Climate Agreement How it works and why it matters

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016 saw a landmark in humanity’s attempt to tackle climate change as 195 countries came together to sign the Paris Climate Agreement. For the first time, the global community agreed to work together to “hold the increase in the global average temperature to well below 2 °C (3.6 °F) above pre-industrial levels”.

2 °C doesn’t sound like a significant rise in temperature. If your room warmed by 2 °C you would barely feel the change.

However, global warming on this scale greatly increases the risk of extreme weather such as droughts, floods, and storms. This might sound like something out of a Hollywood disaster movie, but in 2016 the world was between 1.3 and 1.5 °C above pre-industrial levels and the effects are beginning to show.

Warming temperatures destroy fragile ecosystems and acidify oceans, while changing weather patterns put a strain on crops. Sea level rise could put the very land that people live on at risk: low lying island nations such as the Bahamas or Fiji are at risk of being swallowed up by the oceans. By limiting—and eventually eliminating—greenhouse gas emissions across the globe, the Paris agreement aims to stop the temperature rise before it reaches this crucial threshold.

Climate change is a global phenomenon.

Atmospheric gases do not respect borders and emissions from one country can affect countries on the other side of the world. For this reason an effective plan to tackle climate change requires global cooperation.

The

agreement requires developed nations to cut more emissions than developing countries which do not yet have the means to transition to cleaner energy sources.

Each country has set a target that it must try to meet. The USA, for example, has pledged to cut emissions by 28 percent of the 2005 level by 2025. Every five years, the countries meet to reassess their objectives, factoring in the latest scientific information. This is also an opportunity to report to the public how successful their strategies to cut emissions have been.

It is heartening that so many countries are taking part in the agreement, but the onus should be on developed countries to tackle climate change as they produce far higher levels of greenhouse gas emissions than developing countries. Just five countries (China, USA, Russia, India and Japan) are responsible for over 50 percent of the total reduction of gases covered in the agreement. All except Russia have formally committed to a reduction by ratifying the agreement.

The Paris agreement is not without its critics. According to the United Nations Environmental Program (UNEP) and a key study in Nature, even if all countries meet their current targets, warming will still be way above 2 °C, and likely closer to 3 °C. This is an agreement that must be updated and strengthened over time if it is to have the desired effect.

Complicating matters further, Donald Trump’s shock election win in the USA could throw a major spanner in the works.

Trump has called global warming a “hoax” and many members of his new cabinet do not believe in anthropogenic climate change, despite overwhelming scientific consensus to the contrary.

During his campaign, Trump called for more oil drilling and greater use of coal, two fossil fuels which contribute to greenhouse gas emissions. With the election won, Trump has become more equivocal about the issue but he remains extremely unpredictable. It is unclear whether Trump will back out of the Paris agreement—the process could take the USA four years. A more radical move would be leaving the UNFCCC, the UN framework that tackles climate change.

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Donald Trump’s shock election win could throw a major spanner in the works”

Trump could choose to simply ignore the aims set out in the Paris agreement, which is not legally binding. If the USA doesn’t meet its target, it would lead to a 20 percent smaller cut in total emissions. A lack of commitment by the USA could also discourage other countries from reducing emissions themselves. However, given how high the stakes are for the planet, the USA not participating is unlikely to negate the Paris agreement totally.

Regardless of whether or not the Paris agreement is realistic, or even achievable, it represents an important first step, paving the way for a reversal of climate change and its effects on our world.

Written by Daniel de Wijze Art by Lucy Allison

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What’s on in Oxford Oxford is home to a wonderful array of science institutions and there are always plenty of exhibitions, talks, and other events in which to get involved. Here are Bang!’s picks of the best events this term.

ON NOW

Back from the Dead: Demystifying Antibiotics Last year marked the 75th anniversary since the first human trials of penicillin, the first antibiotic drug to be discovered.

This special exhibition at the Museum of the History of Science on Broad Street charts the drug’s miraculous and precarious history, from its development at the Sir William Dunn School of Pathology in Oxford during World War Two, through the 20th century ‘golden age’ of antibiotics, to the increasingly relevant threat of antibiotic-resistant bacteria.

Back from the Dead is free to visit and runs until 21st May 2017. Curator-led tours are being regularly run while the exhibition is open—see the museum’s website for more information.

16th FEBRUARY

Super Quiz Show: Pandas Like Porn… And Other Dating Tips Where better to take your Valentine’s date than a fun and interactive comedy quiz show on the science of attraction in the animal kingdom, held at the Story Museum? Over 18s only, tickets £10/£6 concessions. Book to avoid disappointment.

1st MARCH

Who wants to live forever? The biology of ageing Skeptics in the Pub run a series of monthly talks in the top room of St Aldates Tavern. These events are entertaining, informal, and fun to attend either socially or on your own. There is a bar in the room where the talks are held, and entrance is free, although donations to cover speaker expenses are invited.

This month, Professor Alison Woollard from the biochemistry will be discussing the science of ageing. Prof Woollard has performed at a variety of science engagement events, and this evening promises to be a popular one—arrive early to get a seat!

8th MARCH

Famelab UK regional finals Famelab is an international contest run by Cheltenham Science Festival in which STEM students and professionals compete to deliver the best and most innovative three-minute explanation of a scientific concept of their choice. The Oxford regional finals will be held in The Bullingdon bar on Cowley Road, where audience members will be entertained by the best science performances Oxford has to offer, as well as an interval entertainment by last year’s national Famelab winner, maths teacher and folk singer Kyle Evans. Entrance £3, book online to be sure of a place.

At time of going to press, Famelab UK was still open to contestants aged 21 or over- see online for more information.

15th MARCH

The Shaking Palsy: Past, Present and Future of Parkinson’s Disease Oxford neuroscientist Professor Paul Bolam reflects on the history of Parkinson’s disease as well as the directions of future research and therapies in this free lecture at the Natural History Museum. Prior online booking is required.

17th MARCH

Cheats and Deceits Ecologist and renowned science author Dr Martin Stevens comes to The Oxford Playhouse on the 17th March to talk about the incredible and ruthless world of mimicry in nature. Tickets £7, purchase via the theatre’s website.

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rtt

Small talk The world of bacteria is noisier than you might think enough bacteria present (meeting quorum), the autoinducer signal is ‘loud’ enough that they begin a cooperative response. Often, part of the response includes increased production of the autoinducer itself, so that once quorum is reached the response increases even more. Scientists have found many different bacterial species that carry out quorum sensing. The exact details and chemicals involved vary, but they all work on the principle that bacteria will only do something beneficial to the community if enough bacteria are present to make it worthwhile.

So how does this system work in practice? A beautiful example of quorum sensing is found in Vibrio fischeri, a bacterial species that luminesces once the community grows to a sufficient size. The bacteria have a symbiotic relationship with a species of squid which projects the light downward to ‘cancel out’ its shadow and stay hidden from predators.

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ave you ever thought about how you would communicate if you were less than a micrometre long?

Welcome to the noisy world of bacterial communication, where the words are chemicals and the receivers are proteins. This micro-chatter is essential in biofilms, the slimy communities that form when bacteria grow on a surface. Since these bacterial communities can have impacts both on industry and health, scientists are keen to interpret, disrupt, and exploit bacterial communication for our own benefit.

A key question is why bacteria bother to communicate in the first place. Just like many animals, including ourselves, bacteria tend to live together in communities, particularly when they settle on a surface and clump together to form biofilms. This includes biological surfaces, such as the gut lining or teeth. The members of these thriving

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biofilm communities work together, producing shared public goods, like enzymes and other proteins, which promote growth and survival. Just as with animals, in order for bacterial communities to interact and cooperate for the common good, they need some form of communication.

The best studied bacterial communication system is quorum sensing. The name comes from the minimum number of members of a club or society required to be present for a meeting to take place: the quorum. The bacterial version is less bureaucratic, but still relies on a minimum number of bacteria being present.

Quorum sensing begins with bacteria producing a chemical called an autoinducer, which acts as an “I’m here!” signal to other bacteria. The bacteria are all listening out for each other, and with

Luminescence requires a lot of energy and is not much use if only a few bacteria are around, since they won’t be able to produce an appreciable amount of light. To work out when the community has become big enough to make luminescence worthwhile, the bacteria need to communicate their presence to each other.

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To cooperate, bacteria need to communicate”

This is where quorum sensing comes in. Luminescence in V. fisheri is regulated by two proteins, LuxI and LuxR. The LuxI protein controls production of the autoinducer, which moves out of the cell into other neighbouring bacteria, telling them “I’m here, and ready to luminesce”. Meanwhile, the LuxR protein ‘listens’ out for autoinducer. As more and more bacteria produce the autoinducer, the concentration of au-

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toinducer within each individual increases. Once the concentration of autoinducer inside the bacteria reaches a critical concentration, it binds with LuxR. This is the signal that quorum has been met, triggering LuxR to activate genes involved in luminescence.

It’s a simple and elegant communication system to coordinate a group behaviour.

“

It’s a simple and elegant communication system to coordinate a group behaviour”

However, just like us, bacteria are able to tell lies and cheat the system.

Such ‘lies’ have been recorded in Pseudomonas aeruginosa, a pathogen that is particularly problematic for people suffering from cystic fibrosis.

The production of protease enzymes

by P. aeruginosa can be considered a public good that helps the whole community gain nutrients, and is under the control of quorum sensing. But some bacteria are sneaky. They produce the autoinducer saying “I’m here, and ready to produce proteases!” but, unlike their cooperative neighbours, they fail to produce any protease of their own. Having contributed to the total autoinducer concentration, triggering community protease productions, these cheaters then freeload off of their neighbours.

As if liars within the group weren’t bad enough, bacteria also have to deal with hackers and radio jammers from outside their own community. Bacterial communities don’t live in isolation, but are in competition for space and resources from other bacteria. Since quorum sensing regulates survival and growth, disrupting the communication systems of another bacterial community, known as quorum quenching, is an effective way to outcompete them.

This hostile quorum quenching can be as simple as inhibiting another com-

munity’s autoinducer as seen in the soil bacterium Bacillus spp. Alternatively, hostile bacteria might mimic their target’s autoinducer in order to bind with the target’s protein receptor, but instead of activating genes involved in the group behaviour, the mimic inhibits or degrades the target’s receptor and prevents a cooperative response from occurring. This tactic is favoured by Staphylococcus aureus, a bacterium that can sometimes cause disease in humans; different strains of S. aureus produce different autoinducers, which promote their own quorum sensing receptors, but specifically inhibit the receptors of other strains.

It’s not just other bacteria that quorum sensing communities have to look out for, but also the plant and animal hosts that they infect. Quorum sensing is often important for establishing an infection and causing disease, yet there is evidence in seaweeds and legumes— as well as mice and humans—that hosts are able to defend themselves from infection using similar quorum sensing disruption mechanisms to those described in bacteria. These natural mechanisms for jamming bacterial communication present exciting possibilities for artificially disrupting quorum sensing which may lead to new therapies against disease and biofilm prevention strategies.

Researchers at Princeton University, led by Professor Bonnie Bassler, are at the frontier of such therapies. They have been investigating quorum sensing in P. aeruginosa as well as Vibrio cholerae, the bacterium responsible for serious global outbreaks of cholera. What they’ve found is that quorum sensing is an important regulator of harmful virulence factors, which enable these bacteria to cause disease. By identifying the key molecules involved in quorum sensing, they have been able to hijack the communication system and prevent the bacteria from producing virulence factors. Already they have had some success demonstrating that this strategy can prevent disease in animal models. With the rising threat of antibiotic resistance, innovative new therapies like this are much needed.

Similar strategies could also be used

to prevent industrial and hospital biofilm formation. The ability of bacteria to communicate and form biofilms allows them to grow almost anywhere, including industrial pipes and machinery, where they can cause a lot of damage.

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Just like us, bacteria are able to tell lies and cheat the system”

More threateningly, biofilms that grow on showerheads and medical equipment in hospitals are a nasty source of infection. One of the public goods produced by bacteria in biofilms, probably under the control of quorum sensing, is a slimy coating, which protects the bacteria from antibiotics, cleaning reagents, and other environmental factors.

This protective coating makes biofilms very difficult to remove, which is what makes them such a menace. Bassler’s team and others have shown that disrupting P. aeruginosa quorum sensing can prevent these biofilms from forming. At the very least, although these strategies may not always destroy biofilms, they may make them more sensitive to traditional cleaning processes.

Research such as Bassler’s is very promising, yet it remains to be seen whether quorum sensing manipulation therapies will move beyond lab models and have a substantial impact in practice. A key hurdle will be finding a way to generally target quorum sensing, as it’s clear that a wide variety of chemicals are used by the numerous bacterial species with which we share our planet. These so-called ‘simple’ bacteria continue to surprise us with their complex mechanisms for survival, and it seems we still have much to learn as we listen in on their fascinating microscopic conversations.

Written by Marianne Clemence Art by Kai Lin Sun

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CLARITY

A new imaging technique allows us to see the brain more clearly than ever before workings of the brain can therefore be constructed.

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LARITY, a brain imaging technique seemingly straight out of a science fiction novel, aims to bring coherence to our understanding of the brain. By making the brain transparent to light whilst maintaining its molecular structure, this futuristic method will help us to see further into the brain than ever before.

The brain is a brilliantly complex organic computer through which our thoughts, feelings, and actions manifest. Somewhere inside that mass of nerve cells and biomolecules are hidden your primary school memories, hatred or love of marmite, and entire vocabulary. Yet we know relatively little about the brain.

One of the reasons for this is that it has been difficult to image in its entirety. The lipid (fat) matter of the brain is opaque and scatters light so that microscopy can only see to a depth of about 1 mm.

Therefore, we normally cut the brain into extremely thin slices that are then imaged and matched up to reconstruct a picture of the whole organ. This is an arduous, time-consuming process and the slicing of the tissue often leads to marring or complete destruction of the delicate cellular arrangement, meaning cellular projections and pathways are frequently lost or mismatched.

Kwanghun Chung and colleagues at Stanford University set upon the task of developing a brain imaging technique fit for the 21st century. The beautiful acro-

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nym, CLARITY, hides a horrifically clunky scientific name: Clear Lipid-exchanged Acrylamide-hybridised Anatomically Rigid Imaging/Immunostaining/In situ hybridisation-compatible Tissue hYdrogel. It has had success in imaging postmortem mouse and human brains and the researchers claim that it can be used to investigate the structure and components of other organs as well.

The process has three mains steps. First the brain is infused with a hydrogel—a tissue-like gel made mostly of water— and heated to form a mesh which keeps the molecular components in place. An electrical voltage is then applied across the tissue to pull out the opaque lipid molecules in a process called electrophoresis. In the second step, the newly transparent brain is subjected to fluorescent marking. Free of that pesky lipid matter, the brain is permeable to large molecules like GFP (Green Fluorescent Protein). GFP can be used to stain important brain components including genetic material, specific genes, antibodies, proteins, and neurotransmitters.

Finally, light microscopy is used to ‘light up’ the fluorescent brain.

One of the most notable aspects of these CLARITY-prepared brains is that they can withstand multiple rounds of staining without tissue degeneration, allowing different molecules to be fluorescently marked with a different colour.

Stunning multicolour images of the inner

According to Professor Kristine Krug, a researcher at Oxford University who has attempted the process, “CLARITY provides a tremendous opportunity to visualize, instead of reconstructing, the actual 3D structure of the brain from mice to humans.” In this intact model of the brain, projections of neurons, nerve cells, can be visualised by using fluorescently-marked antibodies, which recognise particular chemical structures.

This allows them to distinguish one cell type from another so a single neuron can be traced through a maze of other cells. CLARITY technology will allow us unprecedented intimate access to the intricate neural circuitry of the brain.

Although the technique is still in its nascence, being able to study brain structures and their molecular composition simultaneously may help scientists un-

“

This may help scientists uncover links between the brain, behaviour, and disease”

cover links between the brain, disease, and behaviour. CLARITY images of the brain of a deceased autistic child uncovered the presence of ladder-like patterns of neurons connecting back on themselves, a feature also found in mice with autism-like behaviour. CLARITY has also been used in studies on Alzheimer’s disease in human brains and other neurological diseases in animal models.

Like any pioneering technique, CLARITY isn’t perfect: the process is difficult, timeconsuming, and often goes wrong. However, it is early days, and this emerging approach looks set to revolutionise the way we image the brain and may herald an exciting new era of neuroscience.

Written by Anna Bythell Art by Chloë Jacklin

The future through fibre

A new plan to roll out ultra-fast fibre optics

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evolutions in telecommunications over the last half century have created an age of immediacy. We now expect quick access to information and a slow internet connection will leave us feeling frustrated: it is said that millennials are the ‘impatient generation’. Our need for speed has not gone unnoticed by companies offering broadband connection and we are bombarded with adverts featuring a bewildering array of statistics and superlatives to extol just how fast a certain product is.

But it is not just that our impatience is increasing. We live in a world where we need to be able to access more data more quickly. In business, Skype calls are increasingly replacing conventional meetings and the use of cloud storage is ubiquitous. Some studies predict that by 2022 we will require bandwidths in excess of 350 megabits per second (Mbit/s). At this speed it would take less than 2 minutes to download all of the last series of the BBC’s Sherlock in HD. These studies claim such speeds will be needed to keep up with the development of future technologies and an increase in multiple device ownership. Not having sufficient nationwide infrastructure to respond to these future demands could leave us as a country trailing behind the rest of the world in many respects.

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This ultra-fast technology aims to give the UK a future-proof infrastructure”

Indeed, the fear of being left behind by the rest of the world is a concern to the UK government. Rankings for the fastest average internet connection by country puts the UK in 23rd position, far below countries such as Singapore, the country with the fastest peak average internet connection at 98.5Mbit/s, which has invested heavily in a nationwide project to

provide full fibre optic broadband to 90 percent of its population. To address this ‘fibre gap’, the UK is contemplating its strategy for fibre optic infrastructure.

In November 2016, the Chancellor announced that a new Digital Infrastructure Fund of £400 million would be invested in building an ‘ultra-fast’ fibre optic technology capable of delivering 100Mbit/s bandwidth. This ‘ultra-fast’ technology would replace existing hybrid fibre optic and copper cable systems to give the UK a supposedly future-proof infrastructure.

Optical fibres are fine strands of very pure and defect free glass—or in some cases a polymer—about the thickness of a human hair. Data is transmitted as pulses of light, which are reflected off the walls of the fibre such that they zigzag along its length in a process known as total internal reflection. The major benefit of optical fibres over copper cables is that they give a greater bandwidth— more data can be transferred in a given time—even though their cross section is much smaller. Moreover, as they do not use electricity, they are unaffected by electromagnetic fields and they are more secure. There is also the advantage that a signal can be transmitted for many tens of miles before needing to be amplified, reducing the cost of the expensive electronics involved in amplification.

This has made fibre optics a clear choice for long distance telecommunications, where a reliable and high bandwidth medium is needed to transmit lots of data.

However, only two percent of properties in the UK have a true fibre optic connection. This is because optical fibres are predominantly used over long distances to carry data between the local exchange—which acts as a sort of bridge for telecommunications between the local area and the rest of the world—and a street side cabinet—those metal boxes you see on pavements—from which

copper cables are then used between the cabinet and houses nearby. This type of connection is called fibre to the cabinet (FTTC) and is the basis of ‘super-fast’ broadband services which offer over 24Mbit/s bandwidth.

A previous government initiative called Broadband Delivery UK aims for 95 percent of homes to have access to ‘superfast’ broadband by the end of 2017. A true fibre-optic connection, where an optical fibre goes from the local exchange to a ‘splitter’ from which many optical fibres go directly into people’s homes, is required to give ‘ultra-fast’ broadband. This is called fibre to the premises (FTTP). As there is an optical fibre all the way into the home, there are no copper cables at any point to slow things down, which is why FTTP technologies are so much faster.

Building a fully fibre optic network that can meet our needs in the foreseeable future is most likely going to cost more than is provisioned for in the new Digital Infrastructure Fund, even with private investment. Yet the cost of not investing in the technology, and hence ensuring that the whole nation has access to sufficient internet connection, could be even greater given the predicted future of bandwidth demand.

Written by Rachel Kealy Art by Denise Lai

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OMGs and Emojis The internet is changing the way we communicate. Must this be a bad thing?

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he advent of the internet and social media has radically changed the way we communicate. We all know that it is now faster and easier than ever before to get in touch with friends from all around the globe, but few have considered the consequences of this change for the use of language itself. Are we restricted from expressing such subtleties as sarcasm, mood, and seriousness because written communication is now so prevalent?

Does the globalisation of English on the internet threaten the existence of other languages? Is it even possible to achieve an eloquence online that is fully equivalent to spoken language?

The new layer that the internet has added to our communication bears many similarities to traditional spoken language.

The language of the internet generation is so different from that of older generations that the two sometimes have problems communicating. Trying to explain what a meme is, or when it is appropriate to use the winking smiley face, will leave most millennials out of their depth and frustrated.

The fact that the unwritten rules of internet language use come so naturally to younger generations and yet are so difficult to explain is typical of language in general. We are all familiar with the social rules of our native spoken languages—you do not talk in the same way to a waiter as you would to your mother— and we all have intuitions about what is grammatically correct and what is not.

The fact that our language faculty can transpose these abilities onto internet language is particularly impressive.

A simple Google search of how the internet has changed our speach will yield a multitude of articles on internet slang, describing how Facebook and Twitter are transforming the English language for better or for worse. This is unsurprising, as a new communication medium— along with the fact that English is now shared amongst many more people— will inevitably change the repertoire of words available to us.

Perhaps more remarkable is how the in-

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ternet has changed what we understand about the nature of language itself. For example, the use of emoticons and emojis, which have been in popular use for more than 20 years now, complements—and in some cases replaces— the use of words to such an extent that it worries more conservative academics.

They fear for the future of the subtleties, skills, and eloquence of writers, poets, and journalists.

Others linguists think that the use of emojis and animated GIFs show that human linguistic creativity cannot be stopped and will create new channels, as well as making use of those already available. History shows us that linguistic change in a more general sense is inevitable, and that it is almost always initi-

ated by young people. The same is true of the 'invention' of internet language.

Mere written words were not sufficient to accommodate our communicative needs on the internet, so we reinvented pictographs. The first smile emoticon, ‘:-)’, was invented by computer scientist Scott Fahlman in 1982 because there was a need to signal when messages were not to be taken seriously. Similarly, but much more prolifically, we can use modern emoticons to express very complex emotions such as sarcasm, irony, flirtation, and despair.

More recently, animated GIFs have been incorporated into popular messaging platforms, and this development makes it possible for both individuals and corporations to express new and very spe-

cific emotions and reactions. Where emojis are often too general and open to misinterpretation—what do I mean to say if I send you a whale emoji?—GIFs are very particular and even draw on pop-cultural references from TV shows such as Parks and Recreation or The IT Crowd.

“

A new communication medium will inevitably change our repertoire”

It may seem like we are reverting to a time before writing, where drawings on cave walls were the closest we got to written communication. However, in my

opinion this is not a correct interpretation. Throughout history, older generations have always scorned the younger’s disregard for the proper use of language and traditional grammar. There is truth in the idea that the internet language does present novel phenomena, but rather than threatening written language, emojis enrich our written ability, allowing expression of complex emotions on the internet where communication has to be brief and precise. Where previously we were limited to simple punctuation, language has developed so that we can now express complex emotions with one click using just the right GIF. The trend of the global language community converging on a simplified version of English with the aid of pictographs recalls the old utopian ideal of a universal language that could take us back to the pre-Babel era. Linguist Ben Zimmer claims that this may be what we are witnessing. The globalisation of English, the way humour has become

more accessible and easily shared, and the way we can express ourselves with emojis and GIFs knit us together as a global community.

Language is not impoverished by this trend. Rather, it is vitalised. Users of the internet constantly invent new ways of expressing ourselves and there are definite linguistic tendencies in the use of pictorial expressions online, as people switch sociolinguistic code from community to community online as well as in real life.

If we have clear intuitions about which emoticons and emojis are appropriate in which contexts, we are ‘fluent’ in their use. Regardless of what conservative academics may claim, linguistic creativity will expand its boundaries as we become fluent in internet language as well as our own native languages.

Written by Johanne Nedergård Art by Gulnar Mimaroglu

Join the Bang! Team We are seeking talented applicants for our Editing, Creative, Writing, Web, Publicity, and Business teams

To get involved, visit www.bangscience.org/get-involved or email editor@bangscience.org

*Overlays of world at night (white), commercial flight paths (purple) and Facebook friend pairs (blue)

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Bang! talks to...

Marcus du Sautoy is a renowned theoretical mathematician who has recently superseded Richard Dawkins to the role of Simonyi Professor of the Public Understanding of Science at Oxford University. His inventive strategies for integrating science and maths into the public domain include performances at the Royal Opera House, and he has found a way to integrate his love of theatre with love of maths in plays such as X+Y, exploring multiple dimensions and mathematical concepts on the stage. He talked to Bang! about his visions for such communication, All Souls College, his new book, and the limits of scientific endeavour.

How did you first become interested in theoretical mathematics?

I wasn’t very excited by maths at school—I didn’t ‘get it’ immediately— and it wasn’t until I was about twelve or thirteen when the maths teacher at my comprehensive school, in the middle of a lesson, said, “du Sautoy I want to see you after the class.” I thought I was in trouble but he told me he thought I should find out what maths was really about, that it wasn’t really what we were doing in the classroom but something more exciting, something with great stories in. So he recommended a few books to me, and those books opened my eyes. When I saw the really big stories I fell in love with maths. That’s the trouble: education gives us all the grammar and vocabulary, without the stories. And unfortunately the teachers don’t necessarily know the stories themselves, [but] Mr Bailson, with whom I’m still in contact, said “I could see you responding to abstract thinking and I knew the world of mathematics is where you would love to be.” I owe him so much.

I was also very lucky to go to the Royal Institution’s first mathematical Christmas Lectures—it took until 1978 for Christopher Zeeman to find a way to talk to non-experts about maths. That’s who I wanted to be when I grew up, so it was

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Marcus du Sautoy

lovely when I was invited to do the Lectures in 2006.

“

He told me maths was something exciting, with great stories in”

Now you work with symmetry and hyperspace…

I have fallen in love with the power of symmetry. It’s all over the place as a language: in science, nature, art, music... I am trying to understand what symmetries are out there, not just in our three dimensional universe but also in hyperspace, in many dimensions. This becomes relevant for things like telecommunications because a lot of the codes used to encode digital data will use symmetrical objects to preserve its integrity.

But that’s not my drive. Mathematics isn’t about utility, it’s about truth and beauty. I’m very concerned that the government is channelling funds only into short term goals. If they don’t allow scientists to think just for the sake of it we are going to miss many innovations that come out of having that freedom of thought.

“

The government is channelling funds only into short term goals”

So you’re an advocate of blue sky thinking?

I am. I’m not saying everything should be but if you cut that out you lose a lot, which will affect your economy. It’s

in everyone’s interest, I think, to have a balance of targeted research goals and allowing broader thinking.

You’re a mathematician, and have been appointed as the Simonyi Professor of Public Understanding of Science. How do you see the relationship between maths & science?

Mathematics is slightly different from science, because we can prove things with one hundred percent certainty [in mathemtics]. We “stand on the shoulders of giants”—the proofs of the Ancient Greeks are just as true today. But science works on a more evolutionary model, knocking down your predecessor’s theory as you develop new insights. However, I think I fit this position because mathematics really is the language of science and nature.

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Progress will be made by sharing ideas across boundaries”

It has given me a wonderful platform to go beyond my comfort zone of mathematics. I’ve allowed myself to explore, but in all of the expeditions I’ve made into other subjects, there has been mathematics hiding in there. That’s what’s exciting, the interconnections.

For a programme I made on consciousness the most exciting piece of research was by Giulio Tononi, who has a very mathematical approach to explaining the threshold at which the brain might change behaviour to gain a sense of itself. He even has a ‘coefficient of consciousness’.

We compartmentalise subjects too much. I think new progress will be made by sharing ideas across boundaries.

So you see maths as a language?

Yes, I do, and in fact the most significant book that my early teacher recommend-

can bring my own way of thinking, which can be helpful to them. Horizon purposefully chose me as an outsider to neuroscience, but someone who understood science enough to communicate it.

Gove has been attacking experts [“People in this country have had enough of experts”]; in a review of my book someone was saying that [actually] what we need is the ‘right sort of expert’ who has a sympathy with an uninformed audience. Science communication is learning how to have dialogue, how to engage rather than just to explain.

And you are not just preaching to the converted, you’re trying to reach out to non-scientists. I love, for example, the idea of engaging via Mozart at the Royal Opera House. How did these ideas arise?

It’s important to preach to the converted because you have a good audience there, so I’m quite up for contributing to the Cheltenham Science Festival. But the real challenge is accessing people who don’t think of science as being something that’s part of their lives. So that’s why I use the arts, be it music or theatre.

“ ed to me was called The Language of Mathematics. At the time I had wanted to become a linguist because I wanted to join the foreign office and become a spy, but I found I craved something which had an internal logic.

Although mathematics has lots of twists and turns and surprises, everything has a logic to it. That was important to me.

And I realised that maths is the language of nature, the universal language. So mathematics is a good choice for this Chair because I can find connections, while another subject might find it quite hard to range over all the sciences.

Do your programmes on other subjects take you outside your comfort zone?

Scientists in different disciplines have very different ways of thinking. I deal in very precise logical argument, while a biologist may have to relinquish that to navigate the complexity of life—maths is simple compared to biology. It’s about choosing the right language.

Often I have to spend time in that world to appreciate the way [different scientists are] thinking. On the other hand I

The real challenge is accessing people who don’t think science is something that’s part of their lives”

I‘ve done Glastonbury Festival and radio programmes, but one of my proudest projects was with the Royal Opera House where we explained the maths hiding in The Magic Flute, with people coming up and doing experiments to demonstrate chaos theory. For me, this opera is all about the chaos in the music, contrasted with moments of order. Half the audience were opera regulars who’d never seen maths like this before, the other were my followers experiencing

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opera for the first time. It’s a powerful way to hit new audiences and find different ways to tell these stories.

All Souls [where du Sautoy was once a fellow] is something of a mystery to Oxford undergraduates. What’s it like?

All Souls was actually one of the reasons that I branched out beyond classical academia. As a place without undergraduates, [All Souls] is also a place where everyone can just be excited by their research. Although it seems rather insular and secret, it is in fact a very outward looking college with a lot of connections to professions outside of academia, and young Prize Fellows go on to many different things.

I loved going to dinner because you’d have the most extraordinary conversations. One evening I sat next to the features editor of The Times who invited me to write him an article, but I felt I couldn’t.

However, there’s that old Oxford adage, ‘The fellows change but the guests remain the same’, and sure enough, three years later at another grand dinner, that features editor was there again. He exclaimed that I had never written him the article, so I agreed and wrote my first piece in The Times. My experience there was instrumental in my realising we should be sharing our stories beyond departmental seminars.

From your journalism have presumably come your books. Your latest, What We Cannot Know, seems to centre on the limits of scientific knowledge. Will we, or can we, ever ‘know it all’?

Writing these books has been one of my biggest challenges. It’s like running a marathon, or writing a proof. This one sort of grew out of my [Simonyi professorship]: journalists thought I ‘knew it all’, contacting me and asking random questions about science. I started thinking about whether science will ever know it all, or whether certain questions are unanswerable by their nature. We are in an exciting scientific age and this builds a certain expectation about doing, knowing and predicting everything. But are there unknowable things, questions that cannot be answered?

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In mathematics, Gödel’s Incompleteness Theorem says there are true statements about numbers which can never be proven true. It articulates these limitations mathematically, so I wanted to apply this to other sciences. Despite amazing new neuroscientific insights, maybe the meaning of consciousness is unattainable because it is so subjective.

Information cannot travel faster than the speed of light, therefore there is a cosmic horizon beyond which we can get no information. So if the universe is infinite, we will never get the information to know it.

It was a fascinating book to write because it took me into quantum physics, cosmology, neuroscience, biology. Actually the book is as much about what we think and do know, how we know it and the way that we know things has changed. That’s important.

And perhaps it’s amazing that we know any of it.

Yes, that’s something I talk about. How can we know anything? How much of what we think we know is actually true?

There’s a whole theory in philosophy over epistemology that challenges science and the way we do it. New ideas like string theory are real issues for testable theory, but are there layers of the universe that we can never access?

Do you think that our brains’ ability to understand may limit our understanding of, for example, quantum physics – we may not have evolved to understand at this level?

Yes I tackle this kind of issue: what are the challenges that we as humans may not be able to know, and also what might be the nature of the question not the questioner. I agree, the universe is not set up for us as an exercise in the philosophy of science. It would be antiCopernican to think we could know it all.

I don’t expect my cat to be able to understand quantum physics, so presumably there will be other things which are always beyond us humans.

Mathematics is infinite in its nature: we’ve got infinite statements about numbers which will be true, proofs are therefore of larger and larger length,

so there will be some proofs out there that the human brain will not be able to conceive of, limited by time or number of neurons. And how do we navigate the world? Through our senses and the way that we measure things, using our analytic tools to investigate what our own senses cannot. Could an organism that had no light-detecting cells ever come up with the theory of electromagnetism?

Are there layers of the universe that we can never get access to?

“

There will be some proofs out there that the human brain will not be able to conceive”

Do you find the idea of unknown unknowns scary or comforting?

Humans have an ambiguous relationship with ‘the unknown’. On one hand, it’s what drives and excites us, but the inherently unknowable is frightening.

This is why the idea of God comes into the book: we sometimes try to choose answers to fill those gaps. Will some always be unfillable? Nothing is clear. It’s very difficult to say that we will never know something—that’s like a red rag to a scientist!

What’s next in your role in science communication?

I like to have multiple projects on the go! I’m working with the Royal Court Theatre looking to explore a viral outbreak through an audience experience, working with Nick Payne, a fantastic playwright. I’m working towards a new music exhibition which will have a performance element to it, showing there’s symmetry in sound. And I’ve an idea for a new book which is still a secret at the moment.

Interview by Josephine Pepper

RNAgents Manipulating the cellular process of protein manufacture

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esides some chemical differences, ribonucleic acid is a molecule similar to its more famous cousin, deoxyribonucleic acid. Both this RNA and DNA are composed of a backbone of sugar attached to molecules called bases.

The particular sequence of these bases along the backbone is what comprises the genetic code. RNA is a topic at the forefront of modern biological research, but it is only within the past couple of decades that we have even begun to appreciate just how many cellular roles the molecule plays.

“

RNA’s functional diversity is much broader than we could ever have imagined”

Previously, RNA’s place in biology textbooks was largely limited to its role in protein synthesis. The sequence of DNA that makes up a gene is duplicated as an RNA version, termed a messenger RNA (mRNA) since it serves as an intermediate between DNA and protein. The mRNA carries this genetic information to the ribosomes, the protein-making machinery of the cell. There, the sequence of bases is read as three-letter ‘words’ and translated into the string of amino acids that forms a protein. This fundamental concept—gene into mRNA into protein—forms the ‘central dogma’ of biology.

However, this is by no means RNA’s only role. An ongoing explosion of research has revealed that its functional diversity is

much broader than we could ever have imagined. Particularly, it seems RNA is able to switch on or off gene expression in a variety of fascinating ways. For example, some long RNA molecules can bind to a particular section of a chromosome, physically preventing the proteins that switch on genes from accessing the DNA in that region. This is the basis of ‘X-inactivation’ whereby one of the two X-chromosomes in each cell of a mammalian female is switched off to prevent females from producing twice the amount X-chromosome-encoded proteins as males do.

This requires a long RNA called Xist which wraps around one of the X-chromosomes and prevents its genes from being expressed.

Another quite different method of RNAdriven gene regulation is the RNA interference (RNAi) pathway. This is thought to have first evolved as a defence against viruses, since the pathway begins with the recognition of double-stranded RNA, something that is uniquely formed during viral replication. This double-stranded RNA is processed by special proteins into smaller RNA molecules. One short strand of the RNA becomes part of a protein machine called the RNA-Induced Silencing Complex (RISC). The RNA will bind to mRNA of a specific sequence, which allows RISC to block its translation into a protein, thereby preventing the expression of the gene that the mRNA came from.

Many practical uses have accompanied the discovery of RNAi. Scientists have utilised this natural pathway in experiments to switch off genes of interest, while plant breeders have exploited it to create virus-resistant papayas.

However, it seems that its relevance could stretch beyond this. It appears we are by no means the only species hijacking others’ RNAi pathways for our own ends. There is amassing evidence

of small RNAs produced by one organism moving into another and modifying its gene expression, particularly in parasite-host interactions.

An example is the fungus Botrytis cinerea, the cause of grey mould disease in over two hundred plant species. The fungus produces double-stranded RNA molecules that enter the host plant’s cells.

There they are processed by the plant’s RNAi machinery and target genes involved in immunity, thus inhibiting the normal defensive response raised against the fungus. A key point emerging from the lengthening list of similar examples is that this phenomenon has been found in all kinds of organisms, from bacteria manipulating insect hosts to plants controlling viruses, suggesting that cross-species RNAi is a widely-used mechanism.

Research into this topic is in its infancy, with many of the far-reaching questions that will come to define the field still unanswered. How do these interactions evolve? What is the mechanism of RNA transfer between organisms? Does this translate to an ecological or evolutionary scale? Whatever the answers, these discoveries add to the ever-increasing list of biology lying beyond the bounds of the central dogma.

Written by Claire Ramsay Art by Martha Glover

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Monkey say, monkey do New research has challenged our previously held beliefs on primate communication

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lthough we share many similarities with our primate cousins, one thing that sets humans apart is our use of language. Language is a form of communication that uses unique sounds strung together to convey meaning and to express complex and abstract ideas.

It is the primary mode of communication among humans and has become essential is our everyday lives, but our primate relatives have not developed this ability.

While other primates do communicate with sounds, these are nowhere near as developed or complex as human language. Non-human primates have been observed using tools, playing games, and communicating needs nonverbally, as well as taught more specialised skills such as using money, but they have never been taught to speak the word ‘hello’.

There have been numerous studies showing that captive and wild primates exhibit many similar behaviours to humans and are able to communicate and socialise without speech. The use of tools is one example. Various species of monkeys and apes have been observed using rocks as tools to crack open nuts, dig for roots, and open shellfish. Sticks are used to fish food out of crevices and extract grubs and termites. Non-human primates have also been taught to use

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money, in the form of flat metal discs, in exchange for food. Researchers at Yale taught capuchin monkeys to not only use this money, but to understand budgeting and the economics of price inflation, showing that capuchins have the capacity to understand the basic principles of using money in exchange for wants and needs, as well as other economic principles. Our estimation of primate cognition has massively increased over the decades, and these are just a few examples demonstrating the astonishingly wide range of primate cognitive ability.

If primates can learn to use money and tools, concepts previously thought to be unique to human understanding, then could they perhaps be taught to speak?

Our understanding of the answer has changed over time, with one recent study—discussed later in this article— overturning the long-held view that the structure of their vocal cords prevents this.

No other species’ communication approaches human language in terms of its richness, complexity, and flexibility.

While other species are restricted to communicating relatively simple ideas, humans can use language to express

complex, abstract concepts like scientific or political theories. The ability to talk relies on both the anatomy of the vocal tract and proper brain wiring to control it, among many other highly specialised adaptations. Previously it was thought that non-human primates did not possess the vocal tract necessary for speech, but recent research shows that they do: it’s not anatomy that’s holding them back.

The debate over why non-human primates do not produce speech sounds dates back to the time of Darwin, when it was accepted that primates lacked the brain mechanisms needed to control their vocal cords and produce words. In 1969 Philip Lieberman and colleagues proposed a new hypothesis suggesting that the anatomy of the vocal tract inhibited speech in non-human primates. A plaster cast of the oral cavity of a rhesus macaque cadaver mid-bark was used to study the anatomy of the vocal tract. The cast was used by a computer program that tested the range of the rhesus monkey’s vocal tract by altering the shape of the vocal tract, tongue placement, lip rounding, and jaw angles. In addition, the computer model explored vocal tract configurations that may be unrealistic for the macaques to produce. They concluded that the possibility of acoustic vowel space was more restricted in monkeys than humans, indicating that it would be difficult for them to produce vowel sounds. Thus it was concluded that the rhesus monkey, and potentially other nonhuman primates, are prevented from producing the same range of vowel sounds as humans by the anatomy of their vocal tracts.

This work, along with others, meant that anatomical differences were accepted as one reason for differences in communication between humans and other primates- suggesting that human vocal tracts, as well as our cognition, had adapted to the use of language. However, a 2016 study by Fitch et al. has used X-ray video imaging of live monkeys to challenge this previously accepted hypothesis. Fitch and colleagues point out that the 1969 study’s reliance on a cast from a cadaver would not have given an accurate representation of the vocal tract’s full range. For this reason they decided to study multiple live macaques in action, rather than a single cast from a dead one.

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Non-human primates have been taught to use money in exchange for food”

Just like the 1969 study, this study used a computer model of a vocal tract, but this one was based on the X-ray videos of live macaques. They chose five vowel sounds and synthesized them using other monkey noises, grunts and barks, later playing these noises to humans to see if they could discriminate between the vowels. The human subjects were able to discern five different vowels, indicating that monkeys could hypothetically use the full range of their vocal tracts to produce a diverse range of sounds, enough to be used for speech.

Monkey vocal tract configurations were compared to those of female humans, and for most vowels they were similar in shape. They even produced representations, in the form of spectrograms of speech—visual representations of frequencies in a sound—of simple phrases such as “Will you marry me?” to show the lack of restriction on the monkey vocal tract. The computer-generated audio version of this was clearly understandable, further indicating that macaques have the capability to produce enough

sounds to form words and challenging the previously accepted anatomy hypothesis. This does not mean that macaque speech, if they spoke, would sound like human speech, but merely shows the anatomy of their vocal tract would not impede their ability to produce speech sounds.

If macaque vocal tracts are not all that different to our own, this suggests that features of our neurology and cognition are especially important as adaptations for language. For instance, we know that the laryngeal motor cortex (LMC), which controls the movements of our vocal tracts, is needed for speech in humans because damage to this area results in a loss of speech. Researchers showed that rhesus monkeys and humans have homologous LMC structures. However, humans have seven-fold stronger connectivity between the LMC and other cortices of the brain, suggesting that our well-developed LMCs are an adaptation for the fine motor control of the larynx that is involved in speech. Although macaque vocal tracts are flexible enough in theory, they cannot be finely controlled to produce speech sounds like those of humans.

of consonant sounds. They showed that macaques have a vocal tract capable of producing vowel sounds, but speech is not just a bunch of vowels strung together. Vowels are more difficult sounds to make, but consonants are equally as important in speech. For now, we have shown that if they had the proper brain wiring, these macaques would be ready for vowels, not full speech sounds.

However, language is not just about making the correct speech sounds, but being able to use those sounds to form meaningful words and sentences to represent thoughts, something that requires far more than just the correct vocal tract anatomy and brain wiring. This study does not show that macaques are literary geniuses in waiting. Rather, it can help reveal the evolutionary path that took humans to where we are today.

Written by Brianna Steiert Art by Asiyla Radwan

Before textbooks are rewritten, more research needs to be done to further investigate Fitch et al.’s findings, as well as additional research on the production

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Bang! talks to...

Sally Le Page is a DPhil student in the Zoology department at Oxford.

She has a very popular science channel on YouTube called Shed Science and has been widely involved science communication in the ‘real’ world. Her work has been featured in The Guardian, Fortune, and The Wall Street Journal. Bang! gets to know her.

What first inspired you to make videos on YouTube?

I’d always wanted to go into natural history presenting. I love David Attenborough and for a long time my dream was to work for the BBC’s Natural History Unit. However, this is a really competitive area to get into and, aside from the degree I was doing in biology, I didn’t have any relevant experience. Making videos seemed like a good way to bolster my CV alongside studying.

How do you decide which topics to cover? Do you ever find it difficult to know what sort of tone to set it?

I usually have loads of video ideas floating around the back of my mind and then when I have a good idea for how to communicate one of them, that’s the one I’ll do. For instance, one of my friends keeps bees and we’d always wanted to make a video together, so we did one using her hives as a prop to discuss bees.

“

My aim with this channel is to make people realise that science doesn’t have to be dry and boring”

As for the tone, I assume that my viewers don’t have much specific knowledge but that they’ll be quick to pick up new ide-

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Sally Le Page

as. Some of the viewers are studying science at school or university, but it seems like most of them just watch for personal interest. Sometimes people will comment saying they never found science interesting at school but they love my videos. That makes me really happy because my aim with this channel is to make people realise that science doesn’t have to be dry and boring, it’s something you can learn about as a hobby even if you’re not an expert. I’m not a professional musician, but that doesn’t mean I can’t enjoy music.

Your YouTube channel currently has forty thousand subscribers. How did you go about attracting an audience for your videos? Did you spend a while ‘yelling into the void’?

I started out in the ‘golden days’ of YouTube vlogging when there were fewer vloggers out there so it was much easier for individual channels to get noticed.

Back when I first started I’d get in touch with other science vloggers and they’d give me ‘shout outs’ on their channel, so I built up a few thousand subscribers that way. My follower count rocketed in 2016 when I started working with Rooster Teeth [a YouTube media empire with which Sally has a show, called Let Me Clarify].

Do you do all the editing yourself?

Yes. Is it hard?

Kind of, but it’s YouTube so technical standards are low. If your video is poorly edited, but what you’re saying is good, people have a lot of tolerance for that.

So I was fine starting out with really simple stuff and as I got the hang of it I began to use more challenging techniques.

Many people find it strange to listen to their voice on recordings. Do you?

Everyone’s voice sounds different on recordings than it does to them in real life because, when you listen to yourself speaking, you’re listening to reverberations inside your skull that other people

don’t get to hear. Personally, I view them as separate voices—there’s my normal, everyday voice and my ‘video voice’, which is tinny and high pitched by comparison. I’ve spent long enough editing videos that I’ve got used to it though.

As well as your YouTube channel, you’ve done some incredibly cool stuff in the ‘real world’, including interviewing Bill Nye and Neil de Grasse Tyson and speaking in the Royal Institution’s prestigious Faraday Lecture Theatre. How did you go from making videos for your own channel to being employed by others to do all this?

It’s simpler than you might think: I make YouTube videos and people offer me jobs. I’ve never actually directly applied to a science communication job. Each job can give rise to further opportunities.

For instance, in summer 2014 I gave a talk at the Green Man Festival and somebody backstage asked if I’d be interested in speaking at the RI. It’s not just science that you’ve discussed on your channel, you’ve also made a video talking about imposter syndrome and a coming out video.

What was your motivation for those?

The imposter syndrome video was inspired by a talk I saw by Jocelyn Bell Burnell at the Winchester Science Festival.

Bell Burnell is a physicist who was the first to observe radio pulsars but missed out on the Nobel Prize awarded for that discovery. She spoke about what it was like to be one of just three female physics students in her year and how the intimidating behaviour of the others made her feel like she didn’t belong there.

Imposter syndrome [the feeling some people experience that they are not as competent or talented as others believe them to be, accompanied by a fear of being exposed as a fraud] isn’t that big of a problem for me, but I know it’s extremely common in academia. There are people for whom this is much more of an issue, some of whom don’t realise it’s a well-described phenomenon and think it’s just them. When I experienced imposter syndrome, it was a relief to know others felt the same way, and that’s why

I wanted to talk about it in a video.

As for the coming out video, when my channel began to grow in popularity I started to get people speculating about my sexuality because, apparently, short hair makes you gay. I don’t really like talking about my personal life on my channel—why should all these strangers care who I fancy? However, I dislike my personal life being the subject of gossip even more so I decided to make a video about it. It wasn’t just about me though, I used it as an opportunity to draw attention to issues surrounding coming out more generally and the visibility of LGBT people in science, which I think is important. This has completely quashed the gossip, because now if someone in the comments asks “OMG is she gay???” someone else will just answer “Uh, yes.”

“

Female YouTubers have to deal with a lot on a daily basis”

On a related note, has your experience of being a YouTube presenter been affected by being a woman?

Yes, one hundred percent. You have to deal with a lot on a daily basis: com-

ments about your looks, sexual teasing, worrying about your safety, and knowing that, for instance, what you wear in your videos will be picked up on by commenters more than if you were a man. Almost all my subscribers are male, an issue almost all science channels have on YouTube, and we unfortunately haven’t been able to figure out how to attract more female subscribers.

But on the plus side, it does come with job opportunities. For example, General Electric [a US based company that employed Sally to make science videos] were clear that they wanted a female presenter, and the fact that there aren’t many of us around on YouTube meant it was easier for me to be picked.

What’s been the most rewarding thing about your science communication work?

Definitely the friends I’ve been able to make. Thanks to my YouTube channel I’ve had opportunities to talk to other science YouTubers from around the world.

They’re people I get on so well with and wouldn’t have met otherwise.

What’s the most challenging aspect?

I would say it’s having to get used to thousands of people commenting on my personal life. That’s a weird feeling but

it’s pretty unavoidable if you do what I’m doing. Another challenging thing is fitting this work around my PhD. I’m going to have to spend less time on YouTube this year so I can get my project finished in time.

“

Thanks to my YouTube channel I’ve had opportunities to talk to other science YouTubers from around the world”

What’s the silliest thing you’ve ever done for a YouTube video?

The McFly parody song about starfish was pretty silly.

Interview by Ellen Pasternack

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Life-Changing Careers at Oxford BioMedica Oxford BioMedica is a pioneer of gene and cell therapy, with a leading position in lentiviral vector therapy research, development and manufacture. We were founded in 1995 as a spin-out from the University of Oxford’s Department of Biochemistry.

Our world-class lentiviral vector research and development, analytics and cGMP manufacture is helping deliver the future of medicine Our mission is to build a leading, profitable biopharmaceutical company founded on the successful development and commercialisation of breakthrough gene and cell-based medicines.

Through our in-house research and product development programmes, and collaborations with leading academics and industry partners, our goal is to improve the lives of patients all over the world with debilitating and life-threatening diseases whilst creating shareholder value.

We were the first in the world to administer a lentiviral vector gene therapy product directly to patients We are headquartered in Oxford, UK where we operate multiple manufacturing facilities.

At our new head office, Windrush Court – we have just completed extensive refurbishment including the creation of world class laboratories.

We have cGMP approved manufacturing facilities, with process development, industrialisation and analytical capabilities

Join Us… If you want a career in life-changing, cutting edge science; working for a company that puts people at the heart of everything we do, get in touch: hr@oxfordbiomedica.co.uk

www.oxfordbiomedica.co.uk Our partners include Novartis, Sanofi, GlaxoSmithKline and Pfizer, as well as charitable organisations, such as the Foundation for Fighting Blindness, Cure Parkinson’s Trust and the UK Motor Neurone Disease Association

A bit of a fix

How your data corrects itself A STRING

1101

1

1 1

B

1 0

C

1

1 1

0 0

SEND

1010101

0

PARITIES

Now if an error crops up in the string, one or more of the parity bits won’t match up.

Hamming’s clever construction in fact means we know exactly which is wrong and can correct it. The diagram below shows a scenario where our string is sent and an error appears in the first data bit, resulting in the parity bits A and C being wrong. Equally, if the central bit is switched, all three parity bits read false, or, if one of the parity bits itself were in error, it alone would be wrong.

W

hy does that Now! 48 CD you found in the dog basket still work? And why did all 65 texts you sent your ex have to arrive so painfully unscrambled? The world today is full of digital noise, from the phone mast dealing with your complicated relationship to the ‘smart’ fridge crying out to reorder ice cream, our daily lives are played out in millions of 1s and 0s. So how do we stop errors slipping in, or deal with those that do? With just a few simple tricks these strings of bits and bytes can themselves detect and correct errors so that, however scratched that CD, S Club 7 will still sound like S Club 7.

Whilst computer technology has moved on unrecognizably from its roots in the 1940s, every digital communication is still eventually translated into ‘machine code’, a long, long, string of 1 (‘on’) and 0 (‘off’) commands, and sent as pulses of energy. Outside interference can sometimes flip a 1 to a 0, or a 0 to a 1, and change what message is conveyed. Fortunately, by supplying a few additional 1s and 0s, the recipient can detect when an error has occurred and ask the sender to try again, or even correct it automatically.

One solution could be to triplicate every digit in the string, so 010 becomes 000111000, and rely on the idea that whilst one or two digits might be flipped in error, we should still get blocks of roughly 111 and 000 and distinguish what was intended. If we receive a block that looks like 100, 010 or 001, we know

there’s been an error, but it’s still close enough to 000 that we could tentatively correct it.

But if there were two errors and we saw 110, 101 or 011, we’d apply the same logic to conclude that the sender had tried to write 111, and end up with the wrong message. So while we’ve made some progress, we’re adding a lot of extra baggage without gaining much in certainty. IBM reports that over 2.5 billion gigabytes of data were created every day even back in 2012, so tripling this figure would be a slow and costly price to pay.

Thanks to the work of one mathematician, however, there is a better way.

We begin with something called a ‘parity bit’: an extra digit added onto our data which tells us about the total number of 1s in that string. If the number of 1s is even, our parity bit is 0, and if the number is odd it’s 1. So for the strings 010 and 111 we’d add a 1, or for 101 we’d add 0.

Richard Hamming devised a way to use three such digits added to each string of four bits in such a way that if any of the digits are flipped—including the parity bits themselves—the error is spotted and can be corrected. We can visualise this using a sort of Venn diagram: we place our data bits into the intersections of three circles A, B, and C, calculate the matching parity bits for each circle’s contents, and send the whole group of seven.

1 0

RECIEVE

1000101 ERROR

1 1 0

0

1

0

0 CHECK

1 1 0

0 0

DECODE

1101 CORRECT

1010101

In this way, we can accurately pick out any error in a four-bit string using only three additional digits. To do this with our triplicate method we’d need a bulky 12. In fact, by adding one more check digit it’s possible to not only correct a single-bit error, but also detect a two-bit error and avoid false corrections. Hamming showed that this method is in fact a ‘perfect code’—the theoretical minimum number of extra digits we must add to identify such errors. Computer scientists have been working to find similar codes for longer strings ever since.

The theory and practise of error-correcting codes has matured from Hamming’s work in the ‘50s to a hugely important field today as demands for speed and accuracy grow. Surprisingly, Hamming codes in their original form are still used today in computer RAM modules and internal memory, but variations for other applications abound. For instance, the system used on CDs, known as a ReedSoloman code, is so effective that even with a deep scratch, a disc can be read flawlessly. The disc jumping and ruining McFly’s overdue comeback is usually a fault of the laser reader instead. Perhaps there is only so much mathematicians can do.

Written by Ben Lavelle Art by Sophia Malandraki-Miller

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Secret supersocieties Social insects pull off astonishing organisational feats with the help of alien communication systems

E

xisting all around us, but disregarded by most, are the greatest societies the world has ever known. Dating back over 100 million years, they have influenced our climate and drastically engineered the environments within which we live. No, these are not some lasershooting invaders from space hell but the humblest of conquerors, content with going about their day to day lives in the shadows. These are the social insects: ants, termites, and bees, unique in their ability to form colonies numbering millions of individuals. Through pooling their resources and their collective intelligence in very alien modes of communication, the social insects show that relatively simple organisms are capable of feats of ingenuity and invention arguably comparable to our own accomplishments.

Though genetically diverse, the social insects are grouped together through their similar societal structures, centring around a single reproductive ‘queen’ whose only functioning role is to produce young. In most cases, all other individuals in a colony are the queen’s offspring: the ‘workers’. If the queen is the reproductive organ, the workers are the colony’s figurative arms and legs.

They raise the brood, forage for food

and act as the colony’s defence force.

In some species the workers are divided into different role-based ‘castes’ and have specialised traits according to the roles that they fulfil. They range from large ‘soldiers’, acting as the first line of defence with their powerful mandibles, to the tiny ‘minims’ that carefully tend to the young. Such specialised division of labour allows optimisation of both colony resources and time.

Many aspects of insect sensory systems bear functional similarities to our own. They have compound eyes which provide them with vision, as well as antennae which allow them to touch, taste, and smell their way through their habitat. In social animals, the importance of an organism’s senses lie in the fact that they enable communication. This is especially clear in the social insects who must communicate effectively across colonies that can number well into the millions of individuals. The solution to this problem varies between species but some key examples stand out. Here, the insects’ ability to communicate leads to highly complex collective behaviour.

Dancing Bees Bees, like us, are primarily visual creatures. Their compound eyes are sophisticated enough to sense coloured light.

In fact, the bee’s colour vision—along with that of pollinating insects as a whole—is responsible for the diversity of patterns in insect-pollinated flowers, as they compete for the bee’s attention. But once a bee has found a suitable food source, how does it alert its colony-mates back at the hive? It does so through a unique language of dance.

When a honeybee arrives back at the colony after discovering a food source, it will perform a routine known as the waggle dance, with the movements precisely adapted to communicate both the distance and the direction of the flowers.

The bees will dance in a figure of eight, and as it crosses over from one side to the other it will ‘waggle’ its abdomen, releasing various pheromones according to the type of food to be found. The di-

24

rection of the food source from the hive is conveyed by the direction in which the bee is waggling. The dance is also able to express the distance of the food through the exact duration of the waggle portion.

Such modes of communication are sufficient when the hive is composed of perhaps only a few hundred individuals, but in some insect societies the population can exceed that of humanity’s greatest cities. Insects have solved this problem with perhaps the most effective means of communication in the animal kingdom: pheromones.

“

The dance’s movements are precisely adapted to communicate the direction and distance to the food source”

Fungal Farmers While closely related to bees and wasps, the ants have truly taken sociality to the next level. This success is partly due to their use of chemical secretions, termed pheromones, as their primary method of communication. These allow messages to be transferred across millions of individuals within minutes.

One of the most highly developed social systems on earth belongs to the leafcutter ants. Readers may be familiar with the image of leafcutters marching in a line, carrying leaves many times their body weight in their mandibles. It is a common misunderstanding that the ants are carrying the leaves to eat themselves. Instead, the leaves are cut for a far more interesting purpose: ants have invented agriculture, and did so 50 million years before our ancestors were planting their first seeds. These ants are

not growing wheat, rice, or maize, but a type of fungus. Leafcutters are farmers, tending their crop by chewing up leaves to act as fertiliser and tenderly preening the fungus to remove any infection or unwanted invaders. In return the fungus produces ‘gonglydia’, growths containing all the nutrients required by the ants to survive.

Pheromones are extremely diverse in the messages they can transmit, from provoking alarm to advertising sexual availability. In the social insects, especially ants and termites, trail pheromones are key. Everywhere an ant goes it will lay down a chemical trail that serves as its ‘trail of crumbs’ back home. Should it find a food source, it will collect some and retrace its steps, laying down a different signal trail that can be recognised and followed by others, leading to even more pheromone being laid down and strengthening the signal. This process allows ants to navigate impressive distances, quickly discovering the most optimal route.

Termite Towers Distantly related to the ants and bees are the other great social insects, the termites. Descended from social caveliving cockroaches, termites live in the

dark and so are unable to use sight. Like the ants, they are heavily reliant upon pheromones for the transfer of information across the colony.

“

Termites are the greatest architects on the planet”

Termites set themselves apart with their unique success in architecture. Across vast swathes of the Australian and African savannah stand imposing mounds up to 7 m tall and 30 m wide. If the average length of a termite was 1 cm, and we take the average human height to be 1.65 m, this would be equivalent to humans building structures well over a kilometre high.

Writing off these chimneys as mounds of dirt would be a terribly naïve error.

Termites’ towers are meticulously constructed ventilation systems designed to keep the actual colony conditions, located deep underground, at a perfect temperature and humidity for termite life. Termites are the greatest architects on the planet, but success on this scale

could never be achieved without their ability to communicate and co-operate.

The social insects have been working together for over one hundred million years, while our meagre civilizations can be measured in the thousands. It is easy to be unsettled by the mindless efficiency of these insect super-societies in which each individual is willing to sacrifice its reproduction, independence, and even its life to preserve the colony as a whole, without a hope of recognition. Is our society heading in a similar direction, prioritising efficiency over individuality? Are we doomed to eventually living in Aldous Huxley’s Brave New World, where factory-made humans are pre-programmed for their role in society and each individual’s destiny is decided long before its birth in a toast to efficiency? Our never-ending scramble towards greater productivity, from intensive agricultural techniques to increasingly rapid mass communication, means that with each passing year we may ever more aptly be described as a super-society.

Written by Calum Stephenson Art by Chloë Jacklin

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It’s a small world The way our social contacts interconnect shares surprising similarities with many natural phenomena

‘I

t’s a small world’—a phrase you’ve no doubt found yourself saying at least once, especially in the Oxford bubble. In the case of Oxford, this is partly the result of social background and class dynamics—especially when every other person seems to be from North London, or to have imported friendships and social connections directly from their time at public school— but these ‘no way!’ moments are not necessarily limited to the people you might expect.

This phenomenon turns out to be explained by the properties of our social networks. In 1998, Duncan Watts and Steven Henry Strogatz published a landmark paper that described how networks possess a structure that makes these events less surprising.

Not only social networks, but also those of transport, metabolic, neuronal, economic, and internet systems follow this pattern. They showed how these ‘small world networks’ are midway between a random network and an ordered regular one.

Random networks—where each point, or ‘node’, is connected randomly to others— have a high degree of connectedness. However, this model fails to fully capture the structure of real communities, where people within one friendship group are more likely to know another in the same friendship group than someone the other side of

the planet. On the other hand, structured networks capture the reality of social clustering but cannot explain the frequency of surprising connections in social networks.

Watts and Strogatz’s breakthrough was to explore the properties of networks that showed elements of both random and structured networks. They found that, by adding a small percentage of random connections to a structured network, the average distance between nodes is massively reduced, resulting in a high degree of connectedness. These networks capture the reality of social groups—both their clusters and their unexpected connections. Using data from many other sources, including power grids, gene interactions in the worm Caenorhabditis elegans, and the connections between actors, they found that all these networks possessed features of this intermediate state between structured and random networks.

Since Watts and Strogatz’s groundbreaking model, understanding has progressed to realise how differences in strength of interactions within a network, the structure of the links, and also the history of a network can affect the ways that networks respond to change. Some small world networks possess an ‘egalitarian’ structure where every node possesses a similar number of connections, while others have a more uneven ‘aristocratic’ nature, in which a few nodes have considerably more connections than others.

Neuronal connections in the brain of C. elegans show the former, while sexual contact networks in humans show the latter, with a few individuals having more sexual encounters than most others.

The structure of a network has strong implications for how it will respond to attack or fragmentation. Networks with an aristocratic structure fare much better under random attacks as it is

26

unlikely that the key nodes will be lost.

Conversely, egalitarian structures are more vulnerable as it is more likely that the absence of any one node will have a significant effect on the network’s connectivity. Under targeted attacks the reverse is seen. If hubs in the aristocratic network are targeted, its functionality quickly crumbles, whereas, for an egalitarian network, concentrated attacks have little effect. This difference in responses has implications for the prevention of different attacks.

There remain many issues in the study of networks meriting further exploration, such as how to quantify where networks fall on the spectrum of random to structured, the importance of hubs in networks, and how complex networks react to perturbations. However, perhaps the biggest challenge remains in applying this to the many real small networks at all scales of life. For instance, since the Human Genome Project’s completion in 2003 we have a comprehensive list of our genetic sequence, but understanding how our genes interact with each other, as well as with the proteins they encode and the environment around them, remains an enormous challenge.

While science is often accused of reductionism, the study of networks offers a more holistic approach. This gives profound insights and practical implications for the world in which we live, for the social as well as natural sciences. The impact of climate change on ecosystems, the emergence of antibiotic resistance, and rising economic inequality are just three examples of problems that network analysis can play a major role in tackling.

So the discovery that your GP is best friends with your friend’s mum isn’t really so surprising after all. What is more surprising is the scope of possibilities which greater understanding of these small world networks and their properties may have for the future.

Written by Ruby O’Grady Art by Edward Huang

The cocktail party problem Alhough we take it for granted, hearing requires complex unconscious skills

A

s I write this article, I’m sitting in Geneva airport awaiting information about my delayed flight. The myriad noises surrounding me make it a very appropriate location: conversations of people nearby, a baby crying, announcements over the intercom... It’s fascinating that, although all these sounds merge to enter my ears as a single, complex sound wave, my brain is easily able to distinguish which sounds come from which sources.

The process of untangling all these noises is known as auditory scene analysis (ASA), but we still don’t understand how the brain pulls it off. This puzzle is known as the cocktail party problem—how can you discern an individual voice above the background din of chattering voices at a cocktail party?

“

How can you discern an individual voice above a background of chatter?”

A complex sound wave entering the ear contains all the information available to the brain about the direction, distance, frequency composition, and amplitude of many combined sound waves produced by things in the environment. ASA involves segregating these properties and grouping them according to their source in order to build a full picture of the auditory scene. This involves both the grouping of the many properties of a single sound and the grouping of successive chunks of an ongoing sound.

While scientists have identified many cues which can be used for ASA, it’s not well understood how the brain makes use of these cues to contribute to our perceptual experience.

One cue that is used for ASA is the spatial location of the sound. An experiment

in 1999 played two sets of audio instructions to volunteers over headphones.

The words spoken were identical apart from one point when one track said “bird” while the other said “dog”, making it difficult to understand. Because they played the sounds over headphones, the researchers were able to vary the delay of the sound between the two ears by a few milliseconds. Time delays like this are a way that we can distinguish between different sources of sound since when a sound originates closer to one ear than the other, that ear will detect the sound a fraction of a second earlier.

Artificially differentiating the ‘location’ of the two audio streams in this experiment reduced the participants’ confusion.

This experiment show how directional cues can be very useful at distinguishing between different auditory objects.

In fact, in a cocktail party situation it’s quite common for a listener to tilt their head so one ear is closer to the speaker.

This means that the sound will be louder and arrive a few milliseconds earlier in the ear that is closest, maximising the usefulness of the spatial location cue.

Interestingly though, spatial cues are not the most important in ASA, as can

be seen in experiments where they are manipulated artificially. Vowel sounds are composed of combinations of different sound frequencies and if one frequency is changed or removed then it sounds like a different vowel— for example, “ee” to “eh”. If the vowel sounds are presented over headphones, the perceived location of one frequency from the vowel can be changed by creating a delay between the two ears, as described above. If spatial cues contributed heavily to ASA, we’d expect this to be equivalent to removing this frequency and hence change the perceived vowel.

However, there is basically no effect, which suggests that other cues are more important.

One such cue is common onset. This is the seemingly obvious idea that features which start at the same time are likely to come from the same sound. If two frequencies are detected that start within 15 to 30 milliseconds of each other then it’s very likely they are part of the same sound. Conceptually, this is quite simple to understand. The background hum of a TV contains a certain range of frequencies, while the person laughing next to you has a different range of frequencies that start all at the same time. It is easy to separate the ongoing sound from the one just starting. However, it turns out to be quite complicated to investigate this

27

phenomenon experimentally and even harder to explain how the brain can calculate it.

Pitch and timbre are two other features used to distinguish between different voices in a noisy environment. The set of frequencies in speech that determine the perceived pitch tend to be lower for males than females, but also have individual variation. Additionally, voices have different ‘timbre’, the general quality of a voice such as the level of huskiness. If the timbre of a voice is suddenly changed midway through a sentence, it sounds as if the voice has been replaced by a second speaker. Pitch and timbre generally stay the same even when other sound properties are changing over time. An example is a revving car that

is zooming along the street. Although both the volume and spatial location are changing, the pitch and timbre identify the object as a car and you recognise it as one sound.

and the brain produces the best compromise. Neuroscientists are only just beginning to explore the ways in which visual input can influence the auditory system.

The discussion so far has focussed on the auditory system in isolation, but in fact this only occurs very rarely. A great example of the extent to which the visual system influences auditory perception is called the McGurk effect. If you watch a video of a person mouthing the word “far” but the overlaying audio track is saying “bar”, the resulting perceptual experience is something like “var”. You can check out videos online to see this for yourself. This effect occurs because the visual input of mouth position partially overrides the auditory information

It is clear that there are a multitude of factors that influence auditory scene analysis. This makes it especially challenging to improve technology such as hearing aids and cochlear implants, where users often find it difficult to segregate sounds.

It will be interesting to follow future advances as we develop our understanding of how the brain copes with this fascinating problem.

Written by Emily Gowers Art by Sophia Malandraki-Miller

Bang! reviews...

Herding Hemingway’s Cats Kat Arney, Bloomsbury Sigma (2016)

I

first picked up a copy of Herding Hemingway’s Cats by Kat Arney at an event at Blackwell’s, enticed by the billboard showing a cartoon of DNA with cat ears. At this event the author explained that her inspiration for writing the book, as well as the reason behind the name, was the writer Ernest Hemingway’s six-toed cats. The abnormal appendages of these cats were the result of a mutation that indirectly affects proteins involved in body plan determination, with the mutation lying in a regulatory region far away from the gene itself. Arney, who has a PhD in genetics, explained that she was dissatisfied by the over-simplification of genetic concepts in the media and textbooks, so decided to write a book documenting her search for a “genuine understanding of what are genes are and what they do” in the 21st century.

In person, Arney is down to earth, witty, and above all an excellent communicator, explaining complex concepts of gene regulation to a non-specialist audience in just a few words through clever analogies. Refreshingly, she writes in the same informal, jargon-free manner. Her book is just as insightful as any of the most comprehensive genetics textbook, showing that entertaining science writing need not compromise on information.

Herding Hemingway’s Cats is loosely structured around interviews with scientists in different fields, each of whom presents unique perspectives on different aspects of gene regulation. Each meeting is written as a short story, and Arney always begins by describing the idiosyncrasies in the personalities—and offices—of the scientists she meets, reminding us that science is a human endeavour.

Overturning the static view that reduces genes to blueprints for proteins, we discover just a few of the many mechanisms that act cooperatively to control the expression of genes in cells at the right time and in the right place, driving development and evolution. We are also shown examples of genes behaving oddly in phenomena such as RNA editing, transposition, and pseudogenes.

Arney is careful to state that “all metaphors for genetics are flawed at best”. With this caveat in mind, however, her use of funny and intuitive metaphors remains an excellent and entertaining way of making complex ideas easy to understand.

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Reviewed by Zoe Catchpole

Bang! reviews...

Headstrong

52 Women who Changed Science—and the World

Rachel Swaby, Broadway Books (2016)

P

ractically everyone has heard of Marie Curie. She’s “the token woman in a deck of cards featuring famous scientists,” writes Swaby, “the one most likely to crop up in casual conversation, and the scientist to whom all other women in science are compared.” But how many know that her daughter, Irène, was also a very eminent physicist, even becomming the second woman to receive a Nobel Prize in chemistry, 24 years after her mother? In Headstrong, Swaby introduces us to others like Irène Joliot-Curie—female scientists whose contributions have been overlooked by history. The women in these pages discovered stars and moons, treatments for deadly diseases, the molecular workings of our cells, the processes of insect metamorphosis and of continental drift, the list goes on and on. All too often their names are forgotten. Before reading Headstrong I’d only heard of 12 of these amazing scientists, but they all overcame adversity and deliberate obstruction to make significant contributions to their fields, and every one of them deserves greater recognition.

Headstrong tells the stories of 52 female scientists, with the suggestion that you read one every week for a year, but it’s equally suited to reading in just a couple of sittings, or simply dipping into as you please. Each biography is just a couple of pages long and uses clear, engaging explanations that are easily digestible by scientists and non-scientists alike. I think this book would make a particularly fantastic gift for any school-aged girl. Who knows, perhaps she’ll be inspired to become the next Irène Joliot-Curie.

Reviewed by Ellen Pasternack

In his own words...

Oxford science historian Dr Allan Chapman discusses his new book,

Physicians, Plagues and Progress:

A History of Western Medicine from Antiquity to Antibiotics.

Lion Books (2017)

P

hysicians, Plagues and Progress is, I hope, far from being a conventional history of medicine. For one thing, it shows that medieval science and medicine were in no way the ‘Dark Ages’ of popular mythology. From the 12th century onwards, Europe’s great universities, including Oxford, were pioneering medical teaching. In the noble tradition of Greek medicine, corpses were dissected and medieval surgery was performed by intelligent, educated men who practised sophisticated, humane techniques.

My book revises popular myths about early psychiatric medicine. Indeed, since Hippocrates in 430 BC certain mental diseases had been ascribed to physical causes, while medieval and later physicians and clergy—for many doctors were also Priests— advocated and practised a humane and understanding approach to the mentally ill.

Physicians, too, reminds readers of the hugely important role which Oxford played in the advancement of medicine, from Thomas Willis’s pioneering neurological researches in the 1660s, through to the Dunn School of Pathology, antibiotics, and the ‘Oxford knee’ in modern-day orthopaedics.

And as a lover of anecdotes and good stories, I have included plenty in Physicians.

One such is the account of Anne Green, an Oxfordshire girl hanged in 1650 whom Thomas Willis and his colleagues revived using a novel respiratory technique, bringing lustre to the Medical Faculty. For Physicians is not just medical history, so much as medicine in history.

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