L3

DNA computing is emerging as a versatile technology that promises a vast range of applications, including biosensing, drug delivery and synthetic biology. DNA logic circuits can be achieved in solution using strand displacement reactions, or by decision-making molecular robots-so called 'walkers'-that traverse tracks placed on DNA 'origami' tiles.

 Similarly to conventional silicon technologies, ensuring fault-free DNA circuit designs is challenging, with the difficulty compounded by the inherent unreliability of the DNA technology and lack of scientific understanding. This lecture will give an overview of computational models that capture DNA walker computation and demonstrate the role of quantitative verification and synthesis in ensuring the reliability of such systems. Future research challenges will also be discussed.

Classical work of Jeffery from 1922 established how at low Reynolds number, ellipsoids in steady shear flow undergo periodic motion with non-uniform rotation rate, termed 'Jeffery orbits'.  I will present two problems where Jeffery orbits play a critical role in understanding the transport and aggregation of rod-shaped organisms.  I will discuss the trapping of motile chemotactic bacteria in high shear, and the sedimentation rate of negatively buoyant plankton. 

Part of the series 'What do historians of mathematics do?'

Both as a canonical mathematical text and as a representative of ancient thought, Euclid's Elements of Geometry has been a subject of study since its creation c. 300 BCE. It has been read as a practical and a theoretical text; it has been studied for its philosophical ramifications and for its perceived potential to inculcate logical thought. For the historian, it is where the history of mathematics meets the history of ideas; where the history of the book meets the history of practice. The study of the Elements enjoyed a particular resurgence during the Early Modern period, when around 200 editions of the text appeared between 1482 and 1700.  Depending on their theoretical and practical functions, they ranged between elaborate folios and pocket-size compendia, and were widely studied by scholars, natural philosophers, mathematical practitioners, and schoolchildren alike.

In this talk, I will present some of the preliminary results of the research we have been conducting for the AHRC-funded project based at the History Faculty 'Reading Euclid: Euclid's Elements of Geometry in Early Modern Britain', paying particular attention to how the books were printed, collected, and annotated. I will concentrate on our methodologies and introduce the database we have been building of all the early modern copies of the text in the British Isles, as well as the 'catalogue of book catalogues'.

Part of the series 'What do historians of mathematics do?'

In 1873 the Personal Recollections from Early Life to Old Age of Mary Somerville were published, containing detailed descriptions of her life as a 19th century philosopher, mathematician and advocate of women's rights. In an early draft of this work, Somerville reiterated the widely held view that a fundamental difference between men and women was the latter's lack of originality, or 'genius'.

In my talk I will examine how Somerville's view was influenced by the historic treatment of women, both within scientific research, scientific institutions and wider society. By building on my doctoral research I will also suggest an alternative viewpoint in which her work in the differential calculus can be seen as original, with a focus on her 1834 treatise On the Theory of Differences.

Part of the series 'What do historians of mathematics do?'

In this talk, we will survey the movement of mathematical ideas in the 17th century. We will explore, in particular, the mathematical cultures of Paris, Amsterdam, Rome, Cape Town, Goa, Kyoto, Beijing, and London, as well as the journey of mathematical knowledge on a global scale. As it will be an ambitious task to complete a round-the-world history tour in an hour, the focus will be on East Asia. By employing the digital humanities technique, this presentation will use digital media to effectively show historical sources and help the audience imagine the world as a “round” entity when we discuss a global history of mathematics.

Abstract:
Highlights:

•We increasingly live in a digital world and commercial companies are not the only beneficiaries. The public sector can also use data to tackle pressing issues.
•Machine learning is starting to make an impact on the tools regulators use, for spotting the bad guys, for estimating demand, and for tackling many other problems.
•The speech uses an array of examples to argue that much regulation is ultimately about recognising patterns in data. Machine learning helps us find those patterns.
 
Just as moving from paper maps to smartphone apps can make us better navigators, Stefan’s speech explains how the move from using traditional analysis to using machine learning can make us better regulators.
 
Mini Biography:
 
Stefan Hunt is the founder and Head of the Behavioural Economics and Data Science Unit. He has led the FCA’s use of these two fields and designed several pioneering economic analyses. He is an Honorary Professor at the University of Nottingham and has a PhD in economics from Harvard University.
 

I will explain a new proof of the non-linear stability of the Minkowski spacetime as a solution of the Einstein vacuum equation. The proof relies on an iteration scheme at each step of which one solves a linear wave-type equation globally. The analysis takes place on a suitable compactification of $\mathbb{R}^4$ to a manifold with corners whose boundary hypersurfaces correspond to spacelike, null, and timelike infinity; I will describe how the asymptotic behavior of the metric can be deduced from the structure of simple model operators at these boundaries. This talk is based on joint work with András Vasy.

In this talk we will discuss non-Abelian T-duality as a solution generating technique in type II Supergravity, briefly reviewing its potential to motivate, probe or challenge classifications of supersymmetric solutions, and focusing on the open problem of providing the newly generated AdS brackgrounds with consistent dual superconformal field theories. These can be seen as renormalization fixed points of linear quivers of increasing rank. As illustrative examples, we consider the non-Abelian T-duals of AdS5xS5, the Klebanov-Witten background, and the IIA reduction of AdS4xS7, whose proposed quivers are, respectively, the four dimensional N=2 Gaiotto-Maldacena theories describing the worldvolume dynamics of D4-NS5 brane intersections, its N=1 mass deformations realized as D4-NS5-NS5’, and the three dimensional N=4 Gaiotto-Witten theories, corresponding to D3-D5-NS5. Based on 1705.09661 and 1609.09061.

The horizon conjecture, proved in a case by case basis, states that every supersymmetric smooth horizon admits an sl(2, R) symmetry algebra. However it is unclear how string corrections modify the statement. In this talk I will present the analysis of supersymmetric near-horizon geometries in heterotic supergravity up to two loop order in sigma model perturbation theory, and show the conditions for the horizon to admit an sl(2, R) symmetry algebra. In the second part of the talk, I shall consider the inverse problem of determining all extreme black hole solutions associated to a prescribed near-horizon geometry. I will expand the horizon fields in the radial co-ordinate, the so-called moduli, and show that the moduli must satisfy a system of elliptic PDEs, which implies that the moduli space is finite dimensional.

The talk is based on arXiv:1605.05635 [hep-th] and arXiv:1610.09949 [hep-th].

I will start with briefly describing the HISH ( Holography Inspired Hadronic String) model and reviewing the fits of the spectra of mesons, baryons, glue-balls and exotic hadrons. 

I will present the determination of the hadron strong decay widths. The main decay mechanism is that of a string splitting into two strings. The corresponding total decay width behaves as $\Gamma =\frac{\pi}{2}A T L $ where T and L are the tension and length of the string and A is a dimensionless universal constant. The partial width of a given decay mode is given by $\Gamma_i/\Gamma = \Phi_i \exp(-2\pi C m_\text{sep}^2/T$ where $\Phi_i$ is a phase space factor, $m_\text{sep}$ is the mass of the "quark" and "antiquark" created at the splitting point, and C is adimensionless coefficient close to unity. I will show the fits of the theoretical results to experimental data for mesons and baryons. I will examine both the linearity in L and the exponential suppression factor. The linearity was found to agree with the data well for mesons but less for baryons. The extracted coefficient for mesons $A = 0.095\pm  0.01$  is indeed quite universal. The exponential suppression was applied to both strong and radiative decays. I will discuss the relation with string fragmentation and jet formation. I will extract the quark-diquark structure of baryons from their decays. A stringy mechanism for Zweig suppressed decays of quarkonia will be proposed and will be shown to reproduce the decay width of  states. The dependence of the width on spin and symmetry will be discussed. I will further apply this model to the decays of glueballs and exotic hadrons.