Research into practice : collaboration for leadership in applied health research and care (CLAHRC) for Nottinghamshire, Derbyshire, Lincolnshire (NDL)

To address the problem of translation from research-based evidence to routine healthcare practice, the Collaboration for Leadership in Applied Health Research and Care for Nottinghamshire, Derbyshire, and Lincolnshire (CLAHRC-NDL) was funded by the National Institute for Health Research as one of nine CLAHRCs across England. This paper outlines the underlying theory and its application that CLAHRC-NDL has adopted, as a case example that might be generalised to practice outside the CLAHRC, in comparison to alternative models of implementation

Lyapunov Exponent Pairing for a Thermostatted Hard-Sphere Gas under Shear in the Thermodynamic Limit

We demonstrate why for a sheared gas of hard spheres, described by the SLLOD equations with an iso-kinetic Gaussian thermostat in between collisions, deviations of the conjugate pairing rule for the Lyapunov spectrum are to be expected, employing a previous result that for a large number of particles $N$, the iso-kinetic Gaussian thermostat is equivalent to a constant friction thermostat, up to $1/\sqrt{N}$ fluctuations. We also show that these deviations are at most of the order of the fourth power in the shear rate.Comment: 4 pages, to appear in Rapid Comm., Phys. Rev.

Time-oscillating Lyapunov modes and auto-correlation functions for quasi-one-dimensional systems

The time-dependent structure of the Lyapunov vectors corresponding to the steps of Lyapunov spectra and their basis set representation are discussed for a quasi-one-dimensional many-hard-disk systems. Time-oscillating behavior is observed in two types of Lyapunov modes, one associated with the time translational invariance and another with the spatial translational invariance, and their phase relation is specified. It is shown that the longest period of the Lyapunov modes is twice as long as the period of the longitudinal momentum auto-correlation function. A simple explanation for this relation is proposed. This result gives the first quantitative connection between the Lyapunov modes and an experimentally accessible quantity.Comment: 4 pages, 3 figure

Time-dependent mode structure for Lyapunov vectors as a collective movement in quasi-one-dimensional systems

Time dependent mode structure for the Lyapunov vectors associated with the stepwise structure of the Lyapunov spectra and its relation to the momentum auto-correlation function are discussed in quasi-one-dimensional many-hard-disk systems. We demonstrate mode structures (Lyapunov modes) for all components of the Lyapunov vectors, which include the longitudinal and transverse components of their spatial and momentum parts, and their phase relations are specified. These mode structures are suggested from the form of the Lyapunov vectors corresponding to the zero-Lyapunov exponents. Spatial node structures of these modes are explained by the reflection properties of the hard-walls used in the models. Our main interest is the time-oscillating behavior of Lyapunov modes. It is shown that the largest time-oscillating period of the Lyapunov modes is twice as long as the time-oscillating period of the longitudinal momentum auto-correlation function. This relation is satisfied irrespective of the particle number and boundary conditions. A simple explanation for this relation is given based on the form of the Lyapunov vector.Comment: 39 pages, 21 figures, Manuscript including the figures of better quality is available from http://www.phys.unsw.edu.au/~gary/Research.htm

Hopping dynamics for localized Lyapunov vectors in many-hard-disk systems

The dynamics of the localized region of the Lyapunov vector for the largest Lyapunov exponent is discussed in quasi-one-dimensional hard-disk systems at low density. We introduce a hopping rate to quantitatively describe the movement of the localized region of this Lyapunov vector, and show that it is a decreasing function of hopping distance, implying spatial correlation of the localized regions. This behavior is explained quantitatively by a brick accumulation model derived from hard-disk dynamics in the low density limit, in which hopping of the localized Lyapunov vector is represented as the movement of the highest brick position. We also give an analytical expression for the hopping rate, which is obtained us a sum of probability distributions for brick height configurations between two separated highest brick sites. The results of these simple models are in good agreement with the simulation results for hard-disk systems.Comment: 28 pages, 13 figure

From Lyapunov modes to the exponents for hard disk systems

We demonstrate the preservation of the Lyapunov modes by the underlying tangent space dynamics of hard disks. This result is exact for the zero modes and correct to order $\epsilon$ for the transverse and LP modes where $\epsilon$ is linear in the mode number. For sufficiently large mode numbers the dynamics no longer preserves the mode structure. We propose a Gram-Schmidt procedure based on orthogonality with respect to the centre space that determines the values of the Lyapunov exponents for the modes. This assumes a detailed knowledge of the modes, but from that predicts the values of the exponents from the modes. Thus the modes and the exponents contain the same information

Microscopic expressions for the thermodynamic temperature

We show that arbitrary phase space vector fields can be used to generate phase functions whose ensemble averages give the thermodynamic temperature. We describe conditions for the validity of these functions in periodic boundary systems and the Molecular Dynamics (MD) ensemble, and test them with a short-ranged potential MD simulation.Comment: 21 pages, 2 figures, Revtex. Submitted to Phys. Rev.

What do I do now? Intolerance of uncertainty is associated with discrete patterns of anticipatory physiological responding to different contexts

Heightened physiological responses to uncertainty are a common hallmark of anxiety disorders. Many separate studies have examined the relationship between individual differences in intolerance of uncertainty (IU) and physiological responses to uncertainty during different contexts. Despite this there is a scarcity of research examining the extent to which individual differences in IU are related to shared or discrete patterns of anticipatory physiological responding across different contexts. Anticipatory physiological responses to uncertainty were assessed in three different contexts (associative threat learning and extinction, threat uncertainty, decision-making) within the same sample (n = 45). During these tasks, behavioural responses (i.e. reaction times, choices), skin conductance and corrugator supercilli activity were recorded. In addition, self-reported IU and trait anxiety were measured. IU was related to both skin conductance and corrugator supercilii activity for the associative threat learning and extinction context, and decision-making context. However, trait anxiety was related to corrugator supercilii activity during the threat uncertainty context. Ultimately, this research helps us further tease apart the role of IU on different aspects of anticipation (i.e. valence and arousal) across contexts, which will be relevant for future IU-related models of psychopathology

Stability ordering of cycle expansions

We propose that cycle expansions be ordered with respect to stability rather than orbit length for many chaotic systems, particularly those exhibiting crises. This is illustrated with the strong field Lorentz gas, where we obtain significant improvements over traditional approaches.Comment: Revtex, 5 incorporated figures, total size 200

A Ten-Year Record of Supraglacial Lake Evolution and Rapid Drainage in West Greenland Using an Automated Processing Algorithm for Multispectral Imagery

The rapid drainage of supraglacial lakes introduces large pulses of meltwater to the subglacial environment and creates moulins, surface-to-bed conduits for future melt. Introduction of water to the subglacial system has been shown to affect ice flow, and modeling suggests that variability in water supply and delivery to the subsurface play an important role in the development of the subglacial hydrologic system and its ability to enhance or mitigate ice flow. We developed a fully automated method for tracking meltwater and rapid drainages in large (\u3e 0.125 km2) perennial lakes and applied it to a 10 yr time series of ETM+ and MODIS imagery of an outlet glacier flow band in West Greenland. Results indicate interannual variability in maximum coverage and spatial evolution of total lake area. We identify 238 rapid drainage events, occurring most often at low (\u3c 900 m) and middle (900–1200 m) elevations during periods of net filling or peak lake coverage. We observe a general progression of both lake filling and draining from lower to higher elevations but note that the timing of filling onset, peak coverage, and dissipation are also variable. Lake coverage is sensitive to air temperature, and warm years exhibit greater variability in both coverage evolution and rapid drainage. Mid-elevation drainages in 2011 coincide with large surface velocity increases at nearby GPS sites, though the relationships between ice-shed-scale dynamics and meltwater input are still unclear