Hydrogen peroxide thermochemical oscillator as driver for primordial RNA replication

This paper presents and tests a previously unrecognised mechanism for driving a replicating molecular system on the prebiotic earth. It is proposed that cell-free RNA replication in the primordial soup may have been driven by self-sustained oscillatory thermochemical reactions. To test this hypothesis a well-characterised hydrogen peroxide oscillator was chosen as the driver and complementary RNA strands with known association and melting kinetics were used as the substrate. An open flow system model for the self-consistent, coupled evolution of the temperature and concentrations in a simple autocatalytic scheme is solved numerically, and it is shown that thermochemical cycling drives replication of the RNA strands. For the (justifiably realistic) values of parameters chosen for the simulated example system, the mean amount of replicant produced at steady state is 6.56 times the input amount, given a constant supply of substrate species. The spontaneous onset of sustained thermochemical oscillations via slowly drifting parameters is demonstrated, and a scheme is given for prebiotic production of complementary RNA strands on rock surfaces.Comment: Submitted 14 Nov 2013 to J. Roy. Soc. Interface, accepted in final form 25 Feb 2014. An article on this paper appears on https://theconversation.com/au. A new recipe for primordial soup on the pre-biotic earth may help answer questions about the origin of life, and explain why new life does not emerge from non-living precursors on the modern eart

Representing the riots: the (mis)use of statistics to sustain ideological explanation

This paper analyses the way that figures were used to support two kinds of accounts of the riots of August 2011 prevalent in media coverage and in pronouncements by government ministers. The first of these accounts suggested that the rioters were typically characterised by uncivilized predispositions. The second kind of account suggested that damage to property was typically irrational or indiscriminate. These accounts echo discredited ‘convergence’ and ‘submergence’ explanations in early crowd psychology. We show that the ‘convergence’ explanation – that the rioters were typically ‘career criminals’ or gang-members – was based on arrest figures, treating as unproblematic the circular way that such data was produced (with those already known to the police most likely to be identified and arrested). The ‘submergence account – the suggestion that violence was typically indiscriminate or irrational – was based in part on grouping together attacks on properties in different districts; those areas where 'anyone and anything' was attacked were affluent districts where the target was the rich district itself. Like their academic counterparts, the two types of accounts of the riots of August 2011 are profoundly ideological, for they serve to render the riots marginal and meaningless rather than indicative of wider problems in society

The Influence of Host Condition on Post First Instar Development of the Bronze Birch Borer, \u3ci\u3eAgrilus Anxius\u3c/i\u3e (Coleoptera: Buprestidae)

The bronze birch borer is a contributing factor in birch dieback. It is believed that host condition has a major influence on the development of the borer. We found that the host tree\u27s apparent condition does not appear to influence post first instar development

Detection of Bronze Birch Borer Larvae and Pupae by Radiographs (Coleoptera: Buprestidae)

Bronze birch borer larvae and pupae were detected in small branches through the use of a portable X-ray unit. The optimum exposure time was 40 sec at 55 kV

Partial regularity and smooth topology-preserving approximations of rough domains

For a bounded domain $\Omega\subset\mathbb{R}^m, m\geq 2,$ of class $C^0$, the properties are studied of fields of `good directions', that is the directions with respect to which $\partial\Omega$ can be locally represented as the graph of a continuous function. For any such domain there is a canonical smooth field of good directions defined in a suitable neighbourhood of $\partial\Omega$, in terms of which a corresponding flow can be defined. Using this flow it is shown that $\Omega$ can be approximated from the inside and the outside by diffeomorphic domains of class $C^\infty$. Whether or not the image of a general continuous field of good directions (pseudonormals) defined on $\partial\Omega$ is the whole of $\mathbb{S}^{m-1}$ is shown to depend on the topology of $\Omega$. These considerations are used to prove that if $m=2,3$, or if $\Omega$ has nonzero Euler characteristic, there is a point $P\in\partial\Omega$ in the neighbourhood of which $\partial\Omega$ is Lipschitz. The results provide new information even for more regular domains, with Lipschitz or smooth boundaries.Comment: Final version appeared in Calc. Var PDE 56, Issue 1, 201

Quasistatic nonlinear viscoelasticity and gradient flows

We consider the equation of motion for one-dimensional nonlinear viscoelasticity of strain-rate type under the assumption that the stored-energy function is $\lambda$-convex, which allows for solid phase transformations. We formulate this problem as a gradient flow, leading to existence and uniqueness of solutions. By approximating general initial data by those in which the deformation gradient takes only finitely many values, we show that under suitable hypotheses on the stored-energy function the deformation gradient is instantaneously bounded and bounded away from zero. Finally, we discuss the open problem of showing that every solution converges to an equilibrium state as time $t \to \infty$ and prove convergence to equilibrium under a nondegeneracy condition. We show that this condition is satisfied in particular for any real analytic cubic-like stress-strain function.Comment: 40 pages, 1 figur

Thermodynamics of the deposition of complex waxes and asphaltenes in crude oil

Peer reviewedPublisher PD

Geometry of polycrystals and microstructure

We investigate the geometry of polycrystals, showing that for polycrystals formed of convex grains the interior grains are polyhedral, while for polycrystals with general grain geometry the set of triple points is small. Then we investigate possible martensitic morphologies resulting from intergrain contact. For cubic-to-tetragonal transformations we show that homogeneous zero-energy microstructures matching a pure dilatation on a grain boundary necessarily involve more than four deformation gradients. We discuss the relevance of this result for observations of microstructures involving second and third-order laminates in various materials. Finally we consider the more specialized situation of bicrystals formed from materials having two martensitic energy wells (such as for orthorhombic to monoclinic transformations), but without any restrictions on the possible microstructure, showing how a generalization of the Hadamard jump condition can be applied at the intergrain boundary to show that a pure phase in either grain is impossible at minimum energy.Comment: ESOMAT 2015 Proceedings, to appea