161 research outputs found

    Building resilience through supportive school environments: the Health Promoting Schools Framework as a model for promoting resilience in culturally diverse students

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    Recent World Health Reports note that five of the ten leading causes of disability worldwide relate to mental health problems. These reports refer specifically to the importance of strengthening protective factors as the foundation for positive mental health, namely, fostering resilience. Scant research has addressed determinants of resilience from an organisational or systemic perspective, particularly in settings such as schools or with vulnerable populations such as migrants and refugees. Contemporary interventions predominantly focus on risk factors, both as outcomes and evaluation indicators, rather than shifting to a strengths-based model. Increasing epidemiological evidence confirms that young people who are socially integrated and connected to school, and rate highly on measures of resilience, experience better socioeconomic, educational and health outcomes. This paper reviews key findings from several research projects conducted in Queensland during the past five years. Multilevel models are being used to investigate personal and systemic determinants of human and social capital related to resilience in children and young people within the school setting, including an investigation of protective factors from a cross-cultural perspective. Our research identifies those characteristics of the Health Promoting School that build supportive structures to foster children’s resilience. The empirical results of these key studies will be outlined. A salutogenic model of the pathways by which schools can build their capacity to enhance children’s resilience, through fostering human, cultural and social capital as the foundation for a supportive organisational environment, is presented, including discussion of emerging issues within transcultural mental health promotion

    The depinning transition of a driven interface in the random-field Ising model around the upper critical dimension

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    We investigate the depinning transition for driven interfaces in the random-field Ising model for various dimensions. We consider the order parameter as a function of the control parameter (driving field) and examine the effect of thermal fluctuations. Although thermal fluctuations drive the system away from criticality the order parameter obeys a certain scaling law for sufficiently low temperatures and the corresponding exponents are determined. Our results suggest that the so-called upper critical dimension of the depinning transition is five and that the systems belongs to the universality class of the quenched Edward-Wilkinson equation.Comment: accepted for publication in Phys. Rev.

    Stable ultrahigh-density magneto-optical recordings using introduced linear defects

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    The stability of data bits in magnetic recording media at ultrahigh densities is compromised by thermal `flips' -- magnetic spin reversals -- of nano-sized spin domains, which erase the stored information. Media that are magnetized perpendicular to the plane of the film, such as ultrathin cobalt films or multilayered structures, are more stable against thermal self-erasure than conventional memory devices. In this context, magneto-optical memories seem particularly promising for ultrahigh-density recording on portable disks, and bit densities of \sim100 Gbit inch2^{-2} have been demonstrated using recent advances in the bit writing and reading techniques. But the roughness and mobility of the magnetic domain walls prevents closer packing of the magnetic bits, and therefore presents a challenge to reaching even higher bit densities. Here we report that the strain imposed by a linear defect in a magnetic thin film can smooth rough domain walls over regions hundreds of micrometers in size, and halt their motion. A scaling analysis of this process, based on the generic physics of disorder-controlled elastic lines, points to a simple way by which magnetic media might be prepared that can store data at densities in excess of 1 Tbit inch2^{-2}.Comment: 5 pages, 4 figures, see also an article in TRN News at http://www.trnmag.com/Stories/041801/Defects_boost_disc_capacity_041801.htm

    Depinning transition and thermal fluctuations in the random-field Ising model

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    We analyze the depinning transition of a driven interface in the 3d random-field Ising model (RFIM) with quenched disorder by means of Monte Carlo simulations. The interface initially built into the system is perpendicular to the [111]-direction of a simple cubic lattice. We introduce an algorithm which is capable of simulating such an interface independent of the considered dimension and time scale. This algorithm is applied to the 3d-RFIM to study both the depinning transition and the influence of thermal fluctuations on this transition. It turns out that in the RFIM characteristics of the depinning transition depend crucially on the existence of overhangs. Our analysis yields critical exponents of the interface velocity, the correlation length, and the thermal rounding of the transition. We find numerical evidence for a scaling relation for these exponents and the dimension d of the system.Comment: 6 pages, including 9 figures, submitted for publicatio

    Roughening Transition of Interfaces in Disordered Systems

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    The behavior of interfaces in the presence of both lattice pinning and random field (RF) or random bond (RB) disorder is studied using scaling arguments and functional renormalization techniques. For the first time we show that there is a continuous disorder driven roughening transition from a flat to a rough state for internal interface dimensions 2<D<4. The critical exponents are calculated in an \epsilon-expansion. At the transition the interface shows a superuniversal logarithmic roughness for both RF and RB systems. A transition does not exist at the upper critical dimension D_c=4. The transition is expected to be observable in systems with dipolar interactions by tuning the temperature.Comment: 4 pages, RevTeX, 1 postscript figur

    Width distribution of contact lines on a disordered substrate

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    We have studied the roughness of a contact line of a liquid meniscus on a disordered substrate by measuring its width distribution. The comparison between the measured width distribution and the width distribution calculated in previous works, extended here to the case of open boundary conditions, confirms that the Joanny-de Gennes model is not sufficient to describe the dynamics of contact lines at the depinning threshold. This conclusion is in agreement with recent measurements which determine the roughness exponent by extrapolation to large system sizes.Comment: 4 pages, 3 figure

    Theory of plastic vortex creep

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    We develop a theory for plastic flux creep in a topologically disordered vortex solid phase in type-II superconductors. We propose a detailed description of the plastic vortex creep of the dislocated, amorphous vortex glass in terms of motion of dislocations driven by a transport current jj. The {\em plastic barriers} Upl(j)jμU_{pl}(j)\propto j^{-\mu} show power-law divergence at small drives with exponents μ=1\mu=1 for single dislocation creep and μ=2/5\mu = 2/5 for creep of dislocation bundles. The suppression of the creep rate is a hallmark of the transition from the topologically ordered vortex lattice to an amorphous vortex glass, reflecting a jump in μ\mu from μ=2/11\mu = 2/11, characterizing creep in the topologically ordered vortex lattice near the transition, to its plastic values. The lower creep rates explain the observed increase in apparent critical currents in the dislocated vortex glass.Comment: 4 pages, 1 figur

    Functional Renormalization Group and the Field Theory of Disordered Elastic Systems

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    We study elastic systems such as interfaces or lattices, pinned by quenched disorder. To escape triviality as a result of ``dimensional reduction'', we use the functional renormalization group. Difficulties arise in the calculation of the renormalization group functions beyond 1-loop order. Even worse, observables such as the 2-point correlation function exhibit the same problem already at 1-loop order. These difficulties are due to the non-analyticity of the renormalized disorder correlator at zero temperature, which is inherent to the physics beyond the Larkin length, characterized by many metastable states. As a result, 2-loop diagrams, which involve derivatives of the disorder correlator at the non-analytic point, are naively "ambiguous''. We examine several routes out of this dilemma, which lead to a unique renormalizable field-theory at 2-loop order. It is also the only theory consistent with the potentiality of the problem. The beta-function differs from previous work and the one at depinning by novel "anomalous terms''. For interfaces and random bond disorder we find a roughness exponent zeta = 0.20829804 epsilon + 0.006858 epsilon^2, epsilon = 4-d. For random field disorder we find zeta = epsilon/3 and compute universal amplitudes to order epsilon^2. For periodic systems we evaluate the universal amplitude of the 2-point function. We also clarify the dependence of universal amplitudes on the boundary conditions at large scale. All predictions are in good agreement with numerical and exact results, and an improvement over one loop. Finally we calculate higher correlation functions, which turn out to be equivalent to those at depinning to leading order in epsilon.Comment: 42 pages, 41 figure
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