Evidence-based policing: from effectiveness to cost-effectiveness

Recent years have seen the development of quantitative studies into policing effectiveness, in particular, the ‘evidence based policing’ movement which has encouraged the use of randomized control trials in the UK and the USA. Despite their significance, such studies remain narrowly based in terms of their take-up by academic institutions and police forces. This article charts the rise of evidence-based policing and considers whether it could be taken a step further, by developing consideration of police effectiveness into that of cost-effectiveness. The use of ‘Quality Adjusted Life Years’ (QALY) methodology in the UK in the arena of drugs approval for use by the National Health Service, is considered as a model which might be transferable to policing. It is concluded that there are substantial similarities. Providing that the improvements sought are realistic, there is real potential for the cost-effectiveness of policing methods to be assessed

Simulated LM static reflectivity data, for site P-2-6

Simulated lunar module static reflectivity data for site P-2-

Operational risk, omissions and liability in policing

Recent decades have seen the sensitisation of UK society towards harm and policing ‘failures’ become increasingly significant. This paper is intended to stimulate thought and debate by analysing some consequences of these developments. It reviews literature in relation to risk-taking in UK operational policing, identifying increased criminal and disciplinary liability, particularly in respect of alleged omissions. Hindsight is found to be a potentially powerful influence. The article concludes that it is unlikely that public culture will be changed readily. However, police and other bodies should be able to reach a common approach towards operational risk, omissions and hindsight

A Parameterized Centrality Metric for Network Analysis

A variety of metrics have been proposed to measure the relative importance of nodes in a network. One of these, alpha-centrality [Bonacich, 2001], measures the number of attenuated paths that exist between nodes. We introduce a normalized version of this metric and use it to study network structure, specifically, to rank nodes and find community structure of the network. Specifically, we extend the modularity-maximization method [Newman and Girvan, 2004] for community detection to use this metric as the measure of node connectivity. Normalized alpha-centrality is a powerful tool for network analysis, since it contains a tunable parameter that sets the length scale of interactions. By studying how rankings and discovered communities change when this parameter is varied allows us to identify locally and globally important nodes and structures. We apply the proposed method to several benchmark networks and show that it leads to better insight into network structure than alternative methods.Comment: 11 pages, submitted to Physical Review

Heterotic Vortex Strings

We determine the low-energy N=(0,2) worldsheet dynamics of vortex strings in a large class of non-Abelian N=1 supersymmetric gauge theories.Comment: 44 pages, 3 figures. v2: typos corrected, reference adde

Structure and substrate selectivity of the 750-kDa α6β6 holoenzyme of geranyl-CoA carboxylase.

Geranyl-CoA carboxylase (GCC) is essential for the growth of Pseudomonas organisms with geranic acid as the sole carbon source. GCC has the same domain organization and shares strong sequence conservation with the related biotin-dependent carboxylases 3-methylcrotonyl-CoA carboxylase (MCC) and propionyl-CoA carboxylase (PCC). Here we report the crystal structure of the 750-kDa α6β6 holoenzyme of GCC, which is similar to MCC but strikingly different from PCC. The structures provide evidence in support of two distinct lineages of biotin-dependent acyl-CoA carboxylases, one carboxylating the α carbon of a saturated organic acid and the other carboxylating the γ carbon of an α-β unsaturated acid. Structural differences in the active site region of GCC and MCC explain their distinct substrate preferences. Especially, a glycine residue in GCC is replaced by phenylalanine in MCC, which blocks access by the larger geranyl-CoA substrate. Mutation of this residue in the two enzymes can change their substrate preferences

Zero-temperature criticality in the two-dimensional gauge glass model

The zero-temperature critical state of the two-dimensional gauge glass model is investigated. It is found that low-energy vortex configurations afford a simple description in terms of gapless, weakly interacting vortex-antivortex pair excitations. A linear dielectric screening calculation is presented in a renormalization group setting that yields a power-law decay of spin-wave stiffness with distance. These properties are in agreement with low-temperature specific heat and spin-glass susceptibility data obtained in large-scale multi-canonical Monte Carlo simulations.Comment: 4 pages, 4 figure

Electron Transfer in Donor-Acceptor Systems: Many-Particle Effects and Influence of Electronic Correlations

We investigate electron transfer processes in donor-acceptor systems with a coupling of the electronic degrees of freedom to a common bosonic bath. The model allows to study many-particle effects and the influence of the local Coulomb interaction U between electrons on donor and acceptor sites. Using the non-perturbative numerical renormalization group approach we find distinct differences between the electron transfer characteristics in the single- and two-particle subspaces. We calculate the critical electron-boson coupling alpha_c as a function of $U$ and show results for density-density correlation functions in the whole parameter space. The possibility of many-particle (bipolaronic) and Coulomb-assisted transfer is discussed.Comment: 4 pages, 4 figure