Hamiltonian mappings and circle packing phase spaces

We introduce three area preserving maps with phase space structures which resemble circle packings. Each mapping is derived from a kicked Hamiltonian system with one of three different phase space geometries (planar, hyperbolic or spherical) and exhibits an infinite number of coexisting stable periodic orbits which appear to `pack' the phase space with circular resonances.Comment: 23 pages including 12 figures, REVTEX

Magnitude and variability of land evaporation and its components at the global scale

A process-based methodology is applied to estimate land-surface evaporation from multi-satellite information. GLEAM (Global Land-surface Evaporation: the Amsterdam Methodology) combines a wide range of remotely-sensed observations to derive daily actual evaporation and its different components. Soil water stress conditions are defined from a root-zone profile of soil moisture and used to estimate transpiration based on a Priestley and Taylor equation. The methodology also derives evaporationfrom bare soil and snow sublimation. Tall vegetation rainfall interception is independently estimated by means of the Gash analytical model. Here, GLEAM is applied daily, at global scale and a quarter degree resolution. Triple collocation is used to calculate the error structure of the evaporation estimates and test the relative merits of two different precipitation inputs. The spatial distribution of evaporation – and its different components – is analysed to understand the relative importance of each component over different ecosystems. Annual land evaporation is estimated as 67.9 × 10<sup>3</sup> km<sup>3</sup>, 80% corresponding to transpiration, 11% to interception loss, 7% to bare soil evaporation and 2% snow sublimation. Results show that rainfall interception plays an important role in the partition of precipitation into evaporation and water available for runoff at a continental scale. This study gives insights into the relative importance of precipitation and net radiation in driving evaporation, and how the seasonal influence of these controls varies over different regions. Precipitation is recognised as an important factor driving evaporation, not only in areas that have limited soil water availability, but also in areas of high rainfall interception and low available energy

Global land-surface evaporation estimated from satellite-based observations

This paper outlines a new strategy to derive evaporation from satellite observations. The approach uses a variety of satellite-sensor products to estimate daily evaporation at a global scale and 0.25 degree spatial resolution. Central to this methodology is the use of the Priestley and Taylor (PT) evaporation model. The minimalistic PT equation combines a small number of inputs, the majority of which can be detected from space. This reduces the number of variables that need to be modelled. Key distinguishing features of the approach are the use of microwave-derived soil moisture, land surface temperature and vegetation density, as well as the detailed estimation of rainfall interception loss. The modelled evaporation is validated against one year of eddy covariance measurements from 43 stations. The estimated annual totals correlate well with the stations' annual cumulative evaporation (<i>R</i>=0.80, <i>N</i>=43) and present a low average bias (−5%). The validation of the daily time series at each individual station shows good model performance in all vegetation types and climate conditions with an average correlation coefficient of <i><span style="text-decoration: overline">R</span></i>=0.83, still lower than the <i><span style="text-decoration: overline">R</span></i>=0.90 found in the validation of the monthly time series. The first global map of annual evaporation developed through this methodology is also presented

Economic crisis and the construction of a neo-liberal regulatory regime in Korea

A consistent theme of the literature on the ontology of the 1997 South Korean crisis is the key role played by regulatory failures and the growing weakness of the state. This paper seeks to briefly highlight both the insights and the limitations of this approach to understanding the crisis. Having done so, we shall set out the argument that the crisis created an opportunity for reformist Korean élites to advance their longstanding, but previously frustrated, project to create a comprehensive unambiguously neo-liberal regulatory regime. This paper will also seek to highlight the implications of our reading of the development of the Korean political economy for broader debates on economic liberalisation, crisis and the future of the developmental state

The molecular epidemiology of human immunodeficiency virus type 1 in six cities in Britain and Ireland

The authors sequenced the p17 coding regions of the gag gene from 211 patients infected either through injecting drug use (IDU) or by sexual intercourse between men from six cities in Scotland, N. England, N. Ireland, and the Republic of Ireland. All sequences were of subtype 5. Phylogenetic analysis revealed substantial heterogeneity in the sequences from homosexual men. In contrast, sequence from over 80% of IDUs formed a relatively tight cluster, distinct both from those of published isolates and of the gay men. There was no large-scale clustering of sequences by city in either risk group, although a number of close associations between pairs of individuals were observed. From the known date of the HIV-1 epidemic among IDUs in Edinburgh, the rate of sequence divergence at synonymous sites is estimated to be about 0.8%. On this basis it has been estimated that the date of divergence of the sequences among homosexual men to be about 1975, which may correspond to the origin of the B subtype epidemic

Seizure first aid training for people with Epilepsy (SAFE) frequently attending emergency departments and their significant others : results of a UK multi-centre randomised controlled pilot trial

Objective To determine the feasibility and optimal design of a randomised controlled trial (RCT) of Seizure First Aid Training For Epilepsy (SAFE). Design Pilot RCT with embedded microcosting. Setting Three English hospital emergency departments (EDs). Participants Patients aged ≥16 with established epilepsy reporting ≥2 ED visits in the prior 12 months and their significant others (SOs). Interventions Patients (and their SOs) were randomly allocated (1:1) to SAFE plus treatment-as-usual (TAU) or TAU alone. SAFE is a 4-hour group course. Main outcome measures Two criteria evaluated a definitive RCT’s feasibility: (1) ≥20% of eligible patients needed to be consented into the pilot trial; (2) routine data on use of ED over the 12 months postrandomisation needed securing for ≥75%. Other measures included eligibility, ease of obtaining routine data, availability of self-report ED data and comparability, SAFE’s effect and intervention cost. Results Of ED attendees with a suspected seizure, 424 (10.6%) patients were eligible; 53 (12.5%) patients and 38 SOs consented. Fifty-one patients (and 37 SOs) were randomised. Routine data on ED use at 12 months were secured for 94.1% patients. Self-report ED data were available for 66.7% patients. Patients reported more visits compared with routine data. Most (76.9%) patients randomised to SAFE received it and no related serious adverse events occurred. ED use at 12 months was lower in the SAFE+TAU arm compared with TAU alone, but not significantly (rate ratio=0.62, 95% CI 0.33 to 1.17). A definitive trial would need ~674 patient participants and ~39 recruitment sites. Obtaining routine data was challenging, taking ~8.5 months. Conclusions In satisfying only one predetermined ‘stop/go’ criterion, a definitive RCT is not feasible. The low consent rate in the pilot trial raises concerns about a definitive trial’s finding’s external validity and means it would be expensive to conduct. Research is required into how to optimise recruitment from the target population

Analysis of a spatial Lotka-Volterra model with a finite range predator-prey interaction

We perform an analysis of a recent spatial version of the classical Lotka-Volterra model, where a finite scale controls individuals' interaction. We study the behavior of the predator-prey dynamics in physical spaces higher than one, showing how spatial patterns can emerge for some values of the interaction range and of the diffusion parameter.Comment: 7 pages, 7 figure

Opto-mechanical measurement of micro-trap via nonlinear cavity enhanced Raman scattering spectrum

High-gain resonant nonlinear Raman scattering on trapped cold atoms within a high-fineness ring optical cavity is simply explained under a nonlinear opto-mechanical mechanism, and a proposal using it to detect frequency of micro-trap on atom chip is presented. The enhancement of scattering spectrum is due to a coherent Raman conversion between two different cavity modes mediated by collective vibrations of atoms through nonlinear opto-mechanical couplings. The physical conditions of this technique are roughly estimated on Rubidium atoms, and a simple quantum analysis as well as a multi-body semiclassical simulation on this nonlinear Raman process is conducted.Comment: 7 pages, 2 figure