The SiRi Particle-Telescope System

A silicon particle-telescope system for light-ion nuclear reactions is described. In particular, the system is designed to be optimized for level density and gamma-ray strength function measurements with the so-called Oslo method. Eight trapezoidal modules are mounted at 5 cm distance from the target, covering 8 forward angles between theta = 40 and 54 degrees. The thin front dE detectors (130 micrometer) are segmented into eight pads, determining the reaction angle for the outgoing charged ejectile. Guard rings on the thick back E detectors (1550 micrometer) guarantee low leakage current at high depletion voltage.Comment: 6 pages, 8 figure

Policy Recommendations for Renewable Heating and Cooling in the United Kingdom

A Working Document prepared as part of the IEE project "Policy development for improving RES-H/C penetration in European Member States (RES-H Policy)"The RES-H Policy project: The project "Policy development for improving RES-H/C penetration in European Member States (RES-H Policy)" aims at assisting Member State governments in preparing for the implementation of the forthcoming Directive on Renewables as far as aspects related to renewable heating and cooling (RES-H/C) are concerned. Member States are supported in setting up national sector specific 2020/2030 RES-H/C targets. Moreover the project initiates participatory National Policy Processes in which selected policy options to support RES-H/C are qualitatively and quantitatively assessed. Based on this assessment the project develops tailor made policy options and recommendations as to how to best design a support framework for increased RES-H/C penetration in national heating and cooling markets. The target countries/regions of the project comprise Austria, Greece, Lithuania, The Netherlands, Poland and UK – countries that represent a variety in regard of the framework conditions for RES-H/C. On the European level the projects assesses options for coordinating and harmonising national policy approaches. This results in common design criteria for a general EU framework for RES-H/C policies and an overview of costs and benefits of different harmonised strategies.This Working Document summarises policy recommendations to improve the policy framework for RES-H/C in the United Kingdom. A policy set has been proposed based on the different elements of the policy analysis that has been conducted throughout this project. The document describes the proposed policy instruments and a strategy how to best implement it in the light of the specific national context. It analysis the interaction of the proposed policy set with the existing policy framework (e.g. for the building sector) and provides a proposal for monitoring and evaluating the policy impact on the development of RES-H/C. The report represents a key output of the RES-H Policy project, an EU FP7 funded research project aiming to assist EU Member States in selecting support options for increased renewable heat. It draws on modelling carried out by the Vienna University of Technology and The Dutch Energy Research Centre (ECN) as well as qualitative assessment by the authors. The body of literature in this field is very narrow, particularly given the much less advanced state of renewable heat policy and the significance of heat in developed countries, where it accounts for 40-50% of national energy use.European Commission through the IEE programm

Temporal and dimensional effects in evolutionary graph theory

The spread in time of a mutation through a population is studied analytically and computationally in fully-connected networks and on spatial lattices. The time, t_*, for a favourable mutation to dominate scales with population size N as N^{(D+1)/D} in D-dimensional hypercubic lattices and as N ln N in fully-connected graphs. It is shown that the surface of the interface between mutants and non-mutants is crucial in predicting the dynamics of the system. Network topology has a significant effect on the equilibrium fitness of a simple population model incorporating multiple mutations and sexual reproduction. Includes supplementary information.Comment: 6 pages, 4 figures Replaced after final round of peer revie

Observation of large scissors resonance strength in actinides

The orbital M1-scissors resonance (SR) has been measured for the first time in the quasi-continuum of actinides. Particle-gamma coincidences are recorded with deuteron and 3He induced reactions on 232Th. The residual nuclei 231,232,233Th and 232,233Pa show an unexpectedly strong integrated strength of $B_{M1} = 11-15 \mu_{n}^{2}$ in the Egamma=1.0 - 3.5 MeV region. The increased gamma-decay probability in actinides due to the SR is important for cross-section calculations for future fuel cycles of fast nuclear reactors and may also have impact on stellar nucleosynthesis.Comment: 5 pages and 4 figure

Light-cone distribution amplitudes of octet baryons from lattice QCD

We present lattice QCD results for the wave function normalization constants and the first moments of the distribution amplitudes for the lowest-lying baryon octet. The analysis is based on a large number of $N_f=2+1$ ensembles comprising multiple trajectories in the quark mass plane including physical pion (and kaon) masses, large volumes, and, most importantly, five different lattice spacings down to $a=0.039\,\mathrm{fm}$. This allows us to perform a controlled extrapolation to the continuum and infinite volume limits by a simultaneous fit to all available data. We demonstrate that the formerly observed violation of flavor symmetry breaking constraints can, indeed, be attributed to discretization effects that vanish in the continuum limit

The statistical mechanics of a polygenic characterunder stabilizing selection, mutation and drift

By exploiting an analogy between population genetics and statistical mechanics, we study the evolution of a polygenic trait under stabilizing selection, mutation, and genetic drift. This requires us to track only four macroscopic variables, instead of the distribution of all the allele frequencies that influence the trait. These macroscopic variables are the expectations of: the trait mean and its square, the genetic variance, and of a measure of heterozygosity, and are derived from a generating function that is in turn derived by maximizing an entropy measure. These four macroscopics are enough to accurately describe the dynamics of the trait mean and of its genetic variance (and in principle of any other quantity). Unlike previous approaches that were based on an infinite series of moments or cumulants, which had to be truncated arbitrarily, our calculations provide a well-defined approximation procedure. We apply the framework to abrupt and gradual changes in the optimum, as well as to changes in the strength of stabilizing selection. Our approximations are surprisingly accurate, even for systems with as few as 5 loci. We find that when the effects of drift are included, the expected genetic variance is hardly altered by directional selection, even though it fluctuates in any particular instance. We also find hysteresis, showing that even after averaging over the microscopic variables, the macroscopic trajectories retain a memory of the underlying genetic states.Comment: 35 pages, 8 figure

Survival-extinction phase transition in a bit-string population with mutation

A bit-string model for the evolution of a population of haploid organisms, subject to competition, reproduction with mutation and selection is studied, using mean field theory and Monte Carlo simulations. We show that, depending on environmental flexibility and genetic variability, the model exhibits a phase transtion between extinction and survival. The mean-field theory describes the infinite-size limit, while simulations are used to study quasi-stationary properties.Comment: 11 pages, 5 figure