Nonlinear interaction between electromagnetic fields at high temperature

The electron-positron `box' diagram produces an effective action which is fourth order in the electromagnetic field. We examine the behaviour of this effective action at high-temperature (in analytically continued imaginary-time thermal perturbation theory). We argue that there is a finite, nonzero limit as $T\rightarrow \infty$ (where $T$ is the temperature). We calculate this limit in the nonrelativistic static case, and in the long-wavelength limit. We also briefly discuss the self-energy in 2-dimensional QED, which is similar in some respects.Comment: 13 pages, DAMTP 94/3

Automated multi-day tracking of marked mice for the analysis of social behaviour

A quantitative description of animal social behaviour is informative for behavioural biologists and clinicians developing drugs to treat social disorders. Social interaction in a group of animals has been difficult to measure because behaviour develops over long periods of time and requires tedious manual scoring, which is subjective and often non-reproducible. Computer-vision systems with the ability to measure complex social behaviour automatically would have a transformative impact on biology. Here, we present a method for tracking group-housed mice individually as they freely interact over multiple days. Each mouse is bleach-marked with a unique fur pattern. The patterns are automatically learned by the tracking software and used to infer identities. Trajectories are analysed to measure behaviour as it develops over days, beyond the range of acute experiments. We demonstrate how our system may be used to study the development of place preferences, associations and social relationships by tracking four mice continuously for five days. Our system enables accurate and reproducible characterisation of wild-type mouse social behaviour and paves the way for high-throughput long-term observation of the effects of genetic, pharmacological and environmental manipulations

Integrability and Conformal Symmetry in the BCS model

The exactly solvable BCS Hamiltonian of superconductivity is considered from several viewpoints: Richardson's ansatz, conformal field theory, integrable inhomogenous vertex models and Chern-Simons theory.Comment: Latex with macros included, 12 pages, Proceedings of the NATO Advanced Research Workshop on Statistical Field Theories, Como 18-23 June 2001. Editors: Andrea Cappelli and Giuseppe Mussardo. to be published by Kluwer, Academic Publishers. Corrected some typos and further acknowledgment

Combined Superbase Ionic Liquid Approach to Separate CO2 from Flue Gas

[Image: see text] Superbase ionic liquids (ILs) with a trihexyltetradecylphosphonium cation and a benzimidazolide ([P(66614)][Benzim]) or tetrazolide ([P(66614)][Tetz]) anion were investigated in a dual-IL system allowing the selective capture and separation of CO(2) and SO(2), respectively, under realistic gas concentrations. The results show that [P(66614)][Tetz] is capable of efficiently capturing SO(2) in preference to CO(2) and thus, in a stepwise separation process, protects [P(66614)][Benzim] from the negative effects of the highly acidic contaminant. This results in [P(66614)][Benzim] maintaining >53% of its original CO(2) uptake capacity after 30 absorption/desorption cycles in comparison to the 89% decrease observed after 11 cycles when [P(66614)][Tetz] was not present. Characterization of the ILs post exposure revealed that small amounts of SO(2) were irreversibly absorbed to the [Benzim](−) anion responsible for the decrease in CO(2) capacity. While optimization of this dual-IL system is required, this feasibility study demonstrates that [P(66614)][Tetz] is a suitable sorbent for reversibly capturing SO(2) and significantly extending the lifetime of [P(66614)][Benzim] for CO(2) uptake

Precise Temperature Compensation of Phase in a Rhythmic Motor Pattern

Computational modeling and experimentation in a model system for network dynamics reveal how network phase relationships are temperature-compensated in terms of their underlying synaptic and intrinsic membrane currents

In the shadow of fortress Europe? Impacts of European migration governance on Slovenia, Croatia and Macedonia

This article analyses European integration's effects on migration and border security governance in Slovenia, Croatia and Macedonia in the context of ‘governed interdependence’. We show how transgovernmental networks comprising national and EU actors, plus a range of other participants, blur the distinction between the domestic and international to enable interactions between domestic and international policy elites that transmit EU priorities into national policy. Governments are shown to be ‘willing pupils’ and ‘policy takers’, adapting to EU policy as a pre-condition for membership. This strengthened rather than weakened central state actors, particularly interior ministries. Thus, in a quintessentially ‘national’ policy area, there has been a re-scaling and re-constitution of migration and border security policy. To support this analysis, social network analysis is used to outline the composition of governance networks and analyse interactions and power relations therein

Benefit-Cost Analysis of FEMA Hazard Mitigation Grants

Mitigation ameliorates the impact of natural hazards on communities by reducing loss of life and injury, property and environmental damage, and social and economic disruption. The potential to reduce these losses brings many benefits, but every mitigation activity has a cost that must be considered in our world of limited resources. In principle benefit-cost analysis (BCA) can be used to assess a mitigation activity’s expected net benefits (discounted future benefits less discounted costs), but in practice this often proves difficult. This paper reports on a study that refined BCA methodologies and applied them to a national statistical sample of FEMA mitigation activities over a ten-year period for earthquake, flood, and wind hazards. The results indicate that the overall benefit-cost ratio for FEMA mitigation grants is about 4 to 1, though the ratio varies according to hazard and mitigation type.

Mouse tissue harvest-induced hypoxia rapidly alters the in vivo metabolome, between-genotype metabolite level differences, and 13C-tracing enrichments

OBJECTIVE: Metabolomics as an approach to solve biological problems is exponentially increasing in use. Thus, this a pivotal time for the adoption of best practices. It is well known that disrupted tissue oxygen supply rapidly alters cellular energy charge. However, the speed and extent to which delayed mouse tissue freezing after dissection alters the broad metabolome is not well described. Furthermore, how tissue genotype may modulate such metabolomic drift and the degree to which traced METHODS: By combined liquid chromatography (LC)- and gas chromatography (GC)-mass spectrometry (MS), we measured how levels of 255 mouse liver metabolites changed following 30-second, 1-minute, 3-minute, and 10-minute freezing delays. We then performed test-of-concept delay-to-freeze experiments evaluating broad metabolomic drift in mouse heart and skeletal muscle, differential metabolomic change between wildtype (WT) and mitochondrial pyruvate carrier (MPC) knockout mouse livers, and shifts in RESULTS: Our data demonstrate that delayed mouse tissue freezing after dissection leads to rapid hypoxia-driven remodeling of the broad metabolome, induction of both false-negative and false-positive between-genotype differences, and restructuring of CONCLUSIONS: Our findings provide a previously absent, systematic illustration of the extensive, multi-domain metabolomic changes occurring within the early minutes of delayed tissue freezing. They also provide a novel, detailed resource of mouse liver ex vivo, hypoxic metabolomic remodeling