Sights and sounds of seabed cities

Posted on behalf of Kerri Smith

HERACG001_A3

Stele of Thonis-Heracleion found in Abu Qir Bay, Egypt.{credit}©Franck Goddio / Hilti Foundation. Photo: Christoph Gerigk {/credit}

In his tome Histories, written around 440 BC, the Greek chronicler Herodotus relates the juicy tale of Helen of Troy escaping with her lover Paris (also known as Alexandrus) to a city on the Egyptian coast.

“Now there was (and still is) on the coast a temple of Heracles…” Herodotus wrote of the spot. The city is referenced in a handful of subsequent texts as Heracleion, after the temple. But modern historians and archaeologists searched in vain for traces of Heracleion. It seemed to have vanished.

Enter French archaeologist Franck Goddio, who looked where others had not: under the sea. In the early 1990s he began an intricate survey of the seabed a few kilometres off the north coast of Egypt, in the bay of Abu Qir. In 2000, he and his team found the remains of a city, and reasoned it must be Heracleion. When they found a large inscribed stone referring to a town called Thonis, they realised this must be a city with both Egyptian and Greek names, and christened it Thonis-Heracleion. (Learn more in this Nature Podcast and video.)

Raising the stele of Thonis-Heracleion from the seabed.

Raising the stele of Thonis-Heracleion from the seabed.{credit}©Franck Goddio / Hilti Foundation. Photo: Christoph Gerigk{/credit}

A new exhibition at the British Museum, Sunken Cities, brings some of the most impressive artefacts from Thonis-Heracleion and nearby Canopus to London, de-salinated, de-barnacled and standing tall (see Andrew Robinson’s review here), revealing the cities as melting pots of Greek and Egyptian culture.

Kerri Smith is Nature’s podcast editor. She tweets at @minikerri. Hear from Goddio in this interview for the Nature Podcast, and see more in this video about Sunken Cities at the British Museum, Great Russell Street, London WC1B 3DG. The exhibition runs through 27 November.

 

For Nature’s full coverage of science in culture, visit www.nature.com/news/booksandarts.

The equations of love

Posted on behalf of Marten Scheffer

Gustav Klimt, The Kiss, 1907-8

The Kiss (Lovers) by Gustav Klimt, 1908.{credit}Österreichische Galerie Belvedere/Google Cultural Institute{/credit}.

Few topics are as disparate as mathematics and love — or are they? Modeling Love Dynamics (World Scientific, 2016) by systems theorist Sergio Rinaldi and others playfully, but convincingly, makes the point that even amorous relationships cannot escape the fundamental laws of dynamical systems.

The argument propounded by Rinaldi and colleagues builds on the classical framework of coupled differential equations, which have proven so powerful in describing the essence of relationships in nature such as competition, cooperation and predation. The book’s cover illustration hints at the road ahead: it shows Gustav Klimt’s 1908 painting The Kiss (Lovers). A glance inside reveals that art is an essential part of the analysis of the drama of passion — a drama resulting in large part from the interplay of two strong forces, attraction and repulsion. Simple equations illustrated with elegant diagrams show how, depending on personalities, those forces can result in a transient affair, long-lasting stable equilibrium, or everlasting cycles of attraction and repulsion.

Portrait of Francesco Petrarca (Petrarch).

Portrait of Petrarch, whose Canzoniere can be linked to the  limit cycle.{credit}Via Wikimedia Commons{/credit}

Miniature of Laure de Novis, Petrarch's platonic love, 1463.

Miniature of Laure de Noves, who may have been Petrarch’s ‘Laura’.{credit}Laurentian Library, Florence, 1463{/credit}

The tales and poems chosen masterfully illustrate a range of mathematical features. The limit cycle, known for driving the oscillating dynamics of many economic or biological systems, is linked, for instance, to one of the greatest love stories in Western culture. That is, the cyclical 21-year platonic relationship between fourteenth-century Italian humanist and poet Francesco Petrarca (Petrarch) and the married Laura (possibly the Provençal noblewoman Laure de Noves), charted in Petrarch’s celebrated collection Il Canzoniere.

If three variables are mixed in the differential equations of passion, chaotic dynamics can arise. This is illustrated vividly in Henry-Pierre Roché’s semi-autobiographical 1953 novel Jules et Jim (which inspired François Truffaut’s 1962 film of the same name). Roché documents the love triangle between himself, the brilliant and charming journalist Helen Grund and her shy husband Franz Hessel, his best friend. As with the weather, the course of these dynamics is fundamentally unpredictable in the long run, as the smallest event can put things on a different trajectory. This phenomenon is also known as ‘the butterfly effect’, hinging on the idea that the flap of a butterfly’s wing may eventually lead to a hurricane in a distant place.

Other aspects of relationship dynamics generated by the models are illustrated by a range of classics. The complex tides of emotion between Rhett, Scarlett, Ashley and Melanie in Margaret Mitchell’s 1936 blockbuster Gone with the Wind (and the 1939 film directed by Victor Fleming) are tied to the mathematics of alternative basins of attraction. Gabrielle-Suzanne Barbot de Villeneuve’s eighteenth-century fairytale La Belle et La Bête (Beauty and the Beast) exemplifies a saddle-node bifurcation (often referred to as a tipping point) in Beauty’s slow, barely perceptible progress towards the transition from repulsion to attraction — a pattern also seen in the evolving relationship of Elizabeth Bennett and Darcy in Jane Austen’s 1813 novel Pride and Prejudice. The love triangles in Edmond Rostand’s 1897 play Cyrano de Bergerac meanwhile illustrate how temporary bluffing of one partner can sometimes make the difference needed to move the dynamical system from indifference to attraction for a stable love relationship.

When it comes to making mathematics easy, the book saves the best for last. The 40-page appendix is a complete primer on dynamical systems and their bifurcations. Starting with an example of a love model, a simple, lucid text illustrated by elegant drawings explains everything you always wanted to know but never dared to ask about attractors, repellors, saddles, torusses, strange attractors, tipping points and more.

Scientists and artists alike try to capture the essence of things, whether that is atomic structure, the psychological depths of a fictional character or the crystallization of emotion in music. Perhaps this is why the swirling dance between these two seemingly opposite endeavours works out surprisingly well in Modelling Love Dynamics. Clearly, the arts are superior when it comes to capturing the depths of love. Yet disarmingly easy maths powerfully captures the underlying drivers of stable alliances and transient dalliances. What topic is better suited to seduce a broad audience to play with equations?

Marten Scheffer​’s research focuses on complex systems and their adaptability. He is an ecologist and mathematical biologist at Wageningen University and Research Centre and is founder-director of the Synergy Program for Analysing Resilience and Critical Transitions (SparcS). His latest book is Critical Transitions in Nature and Society (Princeton University Press, 2009.)  He is also a multi-instrumentalist and composer.
Marten.Scheffer@wur.nl

 

For Nature’s full coverage of science in culture, visit www.nature.com/news/booksandarts.

Crowdfunding an online tree of life

3Q: James Rosindell and Yan Wong

A branch on the OneZoom online tree of life.

OneZoom lets people sponsor animals and plants on an online tree of life.{credit}OneZoom{/credit}

Putting all living things, from kingdom to species level, onto a single, easy-to-explore ‘tree of life’ is an ambitious project. But a newly formed charity has just gone a long way towards that by releasing the website www.onezoom.org. To crowdfund the new ‘OneZoom’ tree, biodiversity theorist James Rosindell and evolutionary biologist Yan Wong are asking the public to sponsor their favourite animals and plants. Here Rosindell and Wong talk about OneZoom, and why graphics from it have made their way into a fully revised edition of The Ancestor’s Tale – the 2004 classic Wong co-authored with Richard Dawkins.

What is OneZoom?

The fully revised, reissued edition of the 2004 classic by Richard Dawkins and Yan Wong.

The fully revised, reissued edition of the 2004 classic by Richard Dawkins and Yan Wong.

JR: It’s a way of visualizing large evolutionary trees as a branching fractal. Mindboggling quantities of data can be accessed easily and intuitively by panning and zooming in. With this technology we’re aiming to do for the living world what online mapping software like Google Earth has done for the physical world. Just as you might zoom from a map of the globe into a town, you could navigate into vertebrates and then, say, bats on the tree of life. Think of it as a digital natural history museum, aquarium, zoo and botanical gardens rolled into one.

YW: When James first mentioned OneZoom to me, I was in the middle of revising The Ancestor’s Tale. It became clear that the visual attractiveness and potential coverage of the entire tree of life meant OneZoom trees would be a great addition to the book, which attempts to distil the evolution of all life on earth. I looked in detail at around 100 phylogenetic studies that concern the lineage leading from humans back to the origin of life. Synthesising these studies into a single tree was necessary to give rigour to the ‘pilgrimage to the dawn of life’ that we undergo in The Ancestor’s Tale, and formed the backbone for the tree currently used in OneZoom.

What are you hoping to do now with crowdfunding?

Both: thanks largely to projects like the Open Tree of Life, we’ve now got the entire tree of life with over 2.1 million species — practically all known complex lifeforms — in our database. We’ve also developed visualization methods that allow seamless navigation. What we don’t have yet is a software engine capable of dealing with all those species on a normal PC, let alone a mobile phone. So our website currently only reveals a fraction of what is on our database. Our priority is improving the software core that runs behind the tree view so that we can handle all 2.1 million species.

JR: We chose a crowdfunding model where visitors to the site can feel a sense of ownership of the OneZoom tree of life by stamping their name on a leaf of the tree. The species you choose to sponsor is quite personal and that enhances the community feeling without detracting from the underlying scientific core of the project. Some leaves are sponsored by visitors to the website, others have been engraved as gifts from users to people they know, but there are also many wonderful species still available to choose from.

How will your tree stay up-to-date with shifts in the science?

Simiiformes on OneZoom.

A branch on this section is our own family line.{credit}OneZoom{/credit}

JR: The disadvantage of human-drawn illustrations is that they can only be made for small trees and everything needs redrawing when the science is updated. Software that’s built to visualize trees tends to produce outputs more like graphs: simple to update, but lacking in visual design and only comfortable to read for an expert. The OneZoom viewer is unique because although it is easy to explore and visually appealing, it is also automatically generated.

YW: As for the topology of the tree — the order of branching and so forth — we have semi-automated pipelines in place to keep our tree up to date. They tie together several pre-existing, constantly maintained resources. For example, the Open Tree of Life release 5 came out on 7 April, and our pipeline was able to incorporate it and produce a new tree in time for our release less than a month later. However, some important areas of the tree still require hand curation: the main backbone of the tree and popular chunks. This is done as new studies are released. Another automated feature of the tree is our ‘popularity’ measure, based on visits and edits to Wikipedia pages. If there is a sustained increase in interest about a particular taxa on Wikipedia, this influences the prominence (and sponsorship price) of that leaf in the crowdfunding part of OneZoom.

Interview by Daniel Cressey, a reporter for Nature in London. He tweets at @DPCressey.

The fully revised edition of The Ancestor’s Tale was published on 28 April 2016. For further information about it, see www.ancestorstale.net. For more on OneZoom, see www.onezoom.org.

 

For Nature’s full coverage of science in culture, visit www.nature.com/news/booksandarts.

A requiem for recollection

Posted on behalf of Kerri Smith

Elegy-logo-and-title-treatment-NEW2The best science fiction can predict the science of tomorrow and colour the preoccupations of today. It’s too early to tell whether Nick Payne’s new play, Elegy, will do the former, but it certainly takes a powerful swing at the latter.

Payne’s short three-hander, currently at the Donmar Warehouse in London, evokes the challenge of coping with a relative with worsening dementia, a dilemma well-known to many families. The sci-fi twist comes in the form of a new therapy that carries a heavy cost.

We meet a couple in their sixties. Lorna (Zoë Wanamaker) has an unnamed disease, which has taken its toll on her mood and memory. She and partner Carrie (Barbara Flynn) have to decide whether to embark on a radical new treatment, or let her condition continue its march.

In Payne’s world, doctors can map the brain’s tangle of neurons and have learned how to replace some ailing circuits with prosthetic versions. Normal functions such as walking can be preserved or restored. But, the couple is told, the treatment will not be able to reinstate memories from a large chunk of the patient’s adult life: the period during which the couple met and married. Lorna will have to sacrifice a life’s worth of memories with Carrie for a healthy post-op life.

Some of the science fiction has a basis in today’s fact. Neuroscientists are working on the brain’s ‘connectome’ — a map of all the brain’s neural projections. But they are nowhere close to having a complete atlas, let alone a definitive guide of what functions and memories lie where. It’s also unlikely that Lorna’s  surgery would selectively remove memories depending on their age, although one 2009 study suggested that different brain regions help recall memories of different ages.

Patients today have dire choices similar to this. People with Parkinson’s, for instance, might have to choose between a drug with severe side effects, a major operation or a worsening of the movement disorder. But in Elegy, Payne presents a different type of Hobson’s-choice: would you change your ‘self’ to save your life? As Lorna asks, “What life, if it isn’t this life?”

Nina Sosanya and Zoe Wanamaker in Elegy by Nick Payne.

Nina Sosanya and Zoë Wanamaker in Elegy by Nick Payne.{credit}Johan Persson{/credit}

One speech mars the flow. The doctor, Miriam (Nina Sosanya), gives the couple a primer on axons and glutamate that seems lifted from a neuroscience textbook. There are, rightfully, no more such explications. But there are inconsistencies in how we are told the treatment works and what neuroscientists know about how the brain makes memories and stores motor programmes. A more profound integration of neuroscience into the plot might have helped that.

For instance, the therapy Miriam offers — which excises memories that cannot be replaced — is problematic. Memories do not exist in one neural area; they are stored more widely. Likewise, many motor procedures are essentially glorified memories: riding a bike is a classic example. It’s not clear that these would live somewhere entirely and conveniently different from Lorna’s recollections of events in her life.

But the premise needn’t make neuroscientific sense for the plot to touch us. And it does, in part because the characters are so well-portrayed. Wanamaker shows us Lorna’s deterioration viscerally — walking across the stage and wheeling around angrily when she forgets what she wanted there — as well as her struggle to adjust to healthy life after the procedure. Sosanya brings a humanity to Miriam, despite the scientific soliloquies. She also gets to crack a science joke, raising a laugh from the audience when she tells the couple that the treatment works in mice, rats…and zebrafish.

Zoe Wanamaker in Elegy.

Zoë Wanamaker in Elegy.{credit}Johan Persson{/credit}

The play’s structure and dialogue also reflect the fragmentation of Lorna’s memory and the couple’s life together. We start at the end of the story, when Lorna has already undergone treatment, and look back at the beginning of their relationship, their appointments with the doctor and struggle to cope with Lorna’s dementia. The splicing and disjointedness force you to work to figure out where each scene fits and what has come before, evoking the confusion of the condition.

The dialogue is wonderfully natural, yet also crafted to add to the sense of fragmentation. Barely any character finishes a sentence and many important words are missed out, just as people talking about difficult subjects will tail off and let the listener fill in the blanks. “I worry we’re in danger of reducing an extremely complex…” says Miriam, leaving the thought hanging under a barrage of questions from the couple.

In the middle of the stage, a tall tree trunk with a deep split along its length stands in a glass box. When Lorna’s memory clouds, the box fills with smoke. Like the sparse stage and the half-sentences, it is beautiful, disturbing — and memorable.

Kerri Smith is Nature’s podcast editor. She tweets at @minikerri.

Elegy runs at the Donmar Warehouse, 41 Earlham Street, London, through 18 June.

 

For Nature’s full coverage of science in culture, visit www.nature.com/news/booksandarts.