A simple model of unbounded evolutionary versatility as a largest-scale trend in organismal evolution

The idea that there are any large-scale trends in the evolution of biological organisms is highly controversial. It is commonly believed, for example, that there is a large-scale trend in evolution towards increasing complexity, but empirical and theoretical arguments undermine this belief. Natural selection results in organisms that are well adapted to their local environments, but it is not clear how local adaptation can produce a global trend. In this paper, I present a simple computational model, in which local adaptation to a randomly changing environment results in a global trend towards increasing evolutionary versatility. In this model, for evolutionary versatility to increase without bound, the environment must be highly dynamic. The model also shows that unbounded evolutionary versatility implies an accelerating evolutionary pace. I believe that unbounded increase in evolutionary versatility is a large-scale trend in evolution. I discuss some of the testable predictions about organismal evolution that are suggested by the model

Excursion to Strood and Halling

n/

Decarbonisation at home: The contingent politics of experimental domestic energy technologies

This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this recordPolicy efforts to reduce the carbon intensity of domestic energy consumption have, over the last three decades, been dominated by an almost dichotomous reading of the relationship between technology and social change. On the one hand, there is a conception of personal responsibility that constructs domestic energy users as key actors in the adoption and (appropriate) use of low carbon energy technologies; from this perspective, environmental change becomes a matter of mobilising personal capacities such that individuals make better choices. On the other hand, decarbonising homes is conceived to be an outcome of top-down infrastructural interventions, with householders (or end users) positioned as relatively passive agents who will respond to engineered efficiency in linear and predictable ways. In practice, both positions have been found wanting in terms of accounting for how (and why) change happens and in turn delivering on ambitious policy goals. The argument we develop in this article goes beyond critiquing these problematic framings of technology and the locus of agency. Drawing on three contrasting low carbon energy technology projects in the UK, we present an alternative perspective which foregrounds a more experimental, ad hoc and ultimately provisional mode of governing with domestic energy technologies. We reflect on the meaning and political implications of this experimental turn in transforming (and decarbonising) domestic energy practices.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The research on which this paper is based was funded by a grant from EON/EPSRC (EP/G000395/1)

Metallic phase of the quantum Hall effect in four-dimensional space

We study the phase diagram of the quantum Hall effect in four-dimensional (4D) space. Unlike in 2D, in 4D there exists a metallic as well as an insulating phase, depending on the disorder strength. The critical exponent $\nu\approx 1.2$ of the diverging localization length at the quantum Hall insulator-to-metal transition differs from the semiclassical value $\nu=1$ of 4D Anderson transitions in the presence of time-reversal symmetry. Our numerical analysis is based on a mapping of the 4D Hamiltonian onto a 1D dynamical system, providing a route towards the experimental realization of the 4D quantum Hall effect.Comment: 4+epsilon pages, 3 figure

Computational models for the nonlinear analysis of reinforced concrete plates

A finite element computational model for the nonlinear analysis of reinforced concrete solid, stiffened and cellular plates is briefly outlined. Typically, Mindlin elements are used to model the plates whereas eccentric Timoshenko elements are adopted to represent the beams. The layering technique, common in the analysis of reinforced concrete flexural systems, is incorporated in the model. The proposed model provides an inexpensive and reasonably accurate approach which can be extended for use with voided plates

Novel self-assembled morphologies from isotropic interactions

We present results from particle simulations with isotropic medium range interactions in two dimensions. At low temperature novel types of aggregated structures appear. We show that these structures can be explained by spontaneous symmetry breaking in analytic solutions to an adaptation of the spherical spin model. We predict the critical particle number where the symmetry breaking occurs and show that the resulting phase diagram agrees well with results from particle simulations.Comment: 4 pages, 4 figure

Pose-Normalized Image Generation for Person Re-identification

Person Re-identification (re-id) faces two major challenges: the lack of cross-view paired training data and learning discriminative identity-sensitive and view-invariant features in the presence of large pose variations. In this work, we address both problems by proposing a novel deep person image generation model for synthesizing realistic person images conditional on the pose. The model is based on a generative adversarial network (GAN) designed specifically for pose normalization in re-id, thus termed pose-normalization GAN (PN-GAN). With the synthesized images, we can learn a new type of deep re-id feature free of the influence of pose variations. We show that this feature is strong on its own and complementary to features learned with the original images. Importantly, under the transfer learning setting, we show that our model generalizes well to any new re-id dataset without the need for collecting any training data for model fine-tuning. The model thus has the potential to make re-id model truly scalable.Comment: 10 pages, 5 figure