2,160 research outputs found

    Building Global Citizenship through Network Leadership

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    This article is based upon a paper delivered by Anne Beales about the Interrelate group to the International Initiative for Mental Health Leadership, IIMHL, Conference in Killarney, Ireland, May 2010, and developed by the Interrelate group: Daniel Fisher, US, Shaun McNeil, Scotland, Jenny Speed, Australia, Paddy MacGowan, Ireland, Gary Platz, New Zealand, and Joan Edwards-Karmazyn, Canada

    Anaerobic Cultures from Preserved Tissues of Baby Mammoth

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    Microbiological analysis of several cold-preserved tissue samples from the Siberian baby mammoth known as Lyuba revealed a number of culturable bacterial strains that were grown on anaerobic media at 4 C. Lactic acid produced by LAB (lactic acid bacteria) group, usually by members of the genera Carnobacterium and Lactosphera, appears to be a wonderful preservative that prevents other bacteria from over-dominating a system. Permafrost and lactic acid preserved the body of this one-month old baby mammoth and kept it in exceptionally good condition, resulting in this mammoth being the most complete such specimen ever recovered. The diversity of novel anaerobic isolates was expressed on morphological, physiological and phylogenetic levels. Here we discuss the specifics of the isolation of new strains, differentiation from trivial contamination, and preliminary results for the characterization of cultures

    Nonequilibrium dynamics of random field Ising spin chains: exact results via real space RG

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    Non-equilibrium dynamics of classical random Ising spin chains are studied using asymptotically exact real space renormalization group. Specifically the random field Ising model with and without an applied field (and the Ising spin glass (SG) in a field), in the universal regime of a large Imry Ma length so that coarsening of domains after a quench occurs over large scales. Two types of domain walls diffuse in opposite Sinai random potentials and mutually annihilate. The domain walls converge rapidly to a set of system-specific time-dependent positions {\it independent of the initial conditions}. We obtain the time dependent energy, magnetization and domain size distribution (statistically independent). The equilibrium limits agree with known exact results. We obtain exact scaling forms for two-point equal time correlation and two-time autocorrelations. We also compute the persistence properties of a single spin, of local magnetization, and of domains. The analogous quantities for the spin glass are obtained. We compute the two-point two-time correlation which can be measured by experiments on spin-glass like systems. Thermal fluctuations are found to be dominated by rare events; all moments of truncated correlations are computed. The response to a small field applied after waiting time twt_w, as measured in aging experiments, and the fluctuation-dissipation ratio X(t,tw)X(t,t_w) are computed. For (t−tw)∼twα^(t-t_w) \sim t_w^{\hat{\alpha}}, α^<1\hat{\alpha} <1, it equals its equilibrium value X=1, though time translational invariance fails. It exhibits for t−tw∼twt-t_w \sim t_w aging regime with non-trivial X=X(t/tw)≠1X=X(t/t_w) \neq 1, different from mean field.Comment: 55 pages, 9 figures, revte

    Depinning with dynamic stress overshoots: A hybrid of critical and pseudohysteretic behavior

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    A model of an elastic manifold driven through a random medium by an applied force F is studied focussing on the effects of inertia and elastic waves, in particular {\it stress overshoots} in which motion of one segment of the manifold causes a temporary stress on its neighboring segments in addition to the static stress. Such stress overshoots decrease the critical force for depinning and make the depinning transition hysteretic. We find that the steady state velocity of the moving phase is nevertheless history independent and the critical behavior as the force is decreased is in the same universality class as in the absence of stress overshoots: the dissipative limit which has been studied analytically. To reach this conclusion, finite-size scaling analyses of a variety of quantities have been supplemented by heuristic arguments. If the force is increased slowly from zero, the spectrum of avalanche sizes that occurs appears to be quite different from the dissipative limit. After stopping from the moving phase, the restarting involves both fractal and bubble-like nucleation. Hysteresis loops can be understood in terms of a depletion layer caused by the stress overshoots, but surprisingly, in the limit of very large samples the hysteresis loops vanish. We argue that, although there can be striking differences over a wide range of length scales, the universality class governing this pseudohysteresis is again that of the dissipative limit. Consequences of this picture for the statistics and dynamics of earthquakes on geological faults are briefly discussed.Comment: 43 pages, 57 figures (yes, that's a five followed by a seven), revte

    From Relief to Recovery: Peer Support by Consumers Relieves the Traumas of Disasters and Facilitates Recovery from Mental Illness

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    This paper is about the expertise those with a lived experience of recovery from personal trauma can bring to disaster relief efforts in the form of peer support

    Absence of Two-Dimensional Bragg Glasses

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    The stability to dislocations of the elastic phase, or ``Bragg glass'', of a randomly pinned elastic medium in two dimensions is studied using the minimum-cost-flow algorithm for a disordered fully-packed loop model. The elastic phase is found to be unstable to dislocations due to the quenched disorder. The energetics of dislocations are discussed within the framework of renormalization group predictions as well as in terms of a domain wall picture.Comment: 5 pages, REVTEX, 3 figures included. Further information can be obtained from [email protected]

    Spatial distribution of shore-based fishers in the greater Perth Metropolitan area over summer 2010/2011

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    Aerial surveys are a useful technique for estimating numbers of recreational fishers. Following the success of a pilot study to examine the spatial patterns of recreational shore-based fishing activity in the Perth Metropolitan area from April – June 2010, another survey was conducted from December 2010 – February 2011 between Lancelin – Bunbury. More than 7,000 shorebased fishers were counted during 36 aerial flights, with significantly more recorded on morning and afternoon flights, when compared to those conducted at midday. Flights on weekends/public holidays also recorded more fishers than weekdays. The spatial distribution of fishers was variable along the coast, with sandy beaches at the northern and southern sections of the study area having high counts of fishers, along with groynes in the central section. Comparisons with the previous (autumn) study revealed that the northern beaches generally had higher numbers of shore-based fishers in summer, while those in the south had more during autumn. Data from this study assists with understanding the patterns of shore-based recreational fishing occurring along the greater Perth Metropolitan coast. Such information can be used to assist in the design of future on-ground surveys, compliance and education activities

    Thermodynamic Casimir effects involving interacting field theories with zero modes

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    Systems with an O(n) symmetrical Hamiltonian are considered in a dd-dimensional slab geometry of macroscopic lateral extension and finite thickness LL that undergo a continuous bulk phase transition in the limit L→∞L\to\infty. The effective forces induced by thermal fluctuations at and above the bulk critical temperature Tc,∞T_{c,\infty} (thermodynamic Casimir effect) are investigated below the upper critical dimension d∗=4d^*=4 by means of field-theoretic renormalization group methods for the case of periodic and special-special boundary conditions, where the latter correspond to the critical enhancement of the surface interactions on both boundary planes. As shown previously [\textit{Europhys. Lett.} \textbf{75}, 241 (2006)], the zero modes that are present in Landau theory at Tc,∞T_{c,\infty} make conventional RG-improved perturbation theory in 4−ϵ4-\epsilon dimensions ill-defined. The revised expansion introduced there is utilized to compute the scaling functions of the excess free energy and the Casimir force for temperatures T\geqT_{c,\infty} as functions of L≡L/ξ∞\mathsf{L}\equiv L/\xi_\infty, where ξ∞\xi_\infty is the bulk correlation length. Scaling functions of the LL-dependent residual free energy per area are obtained whose L→0\mathsf{L}\to0 limits are in conformity with previous results for the Casimir amplitudes ΔC\Delta_C to O(ϵ3/2)O(\epsilon^{3/2}) and display a more reasonable small-L\mathsf{L} behavior inasmuch as they approach the critical value ΔC\Delta_C monotonically as L→0\mathsf{L}\to 0.Comment: 23 pages, 10 figure

    Bounding biomass in the Fisher equation

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    The FKPP equation with a variable growth rate and advection by an incompressible velocity field is considered as a model for plankton dispersed by ocean currents. If the average growth rate is negative then the model has a survival-extinction transition; the location of this transition in the parameter space is constrained using variational arguments and delimited by simulations. The statistical steady state reached when the system is in the survival region of parameter space is characterized by integral constraints and upper and lower bounds on the biomass and productivity that follow from variational arguments and direct inequalities. In the limit of zero-decorrelation time the velocity field is shown to act as Fickian diffusion with an eddy diffusivity much larger than the molecular diffusivity and this allows a one-dimensional model to predict the biomass, productivity and extinction transitions. All results are illustrated with a simple growth and stirring model.Comment: 32 Pages, 13 Figure
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