Improving quality and equity in schools in socially disadvantaged areas

Background: Recent effectiveness studies have investigated the relationship between two dimensions of effectiveness - namely, quality and equity. Specifically, the question of whether effective schools can also reduce the initial differences in student outcomes attributed to student background factors has been examined. In this context, the Dynamic Approach to School Improvement (DASI) makes use of theory and the research findings of effectiveness studies to try to improve school effectiveness in terms of quality and equity. Purpose: This study aimed to examine whether the implementation of DASI in primary schools in socially disadvantaged areas in four European countries (Cyprus, England, Greece and Ireland) was able to promote student learning outcomes in mathematics and to reduce the impact of student background factors on student achievement in mathematics. Design and methods: A sample of 72 primary schools across the four countries was randomly split into experimental and control groups. At the beginning and at the end of the school year, mathematics tests were administered to all students of Grades 4-6 (n = 5560; student ages 9-12 years). The experimental group made use of DASI. Within-country multilevel regression analyses were conducted to evaluate the impact of the intervention and search for interaction effects between the use of DASI and student background factors on final achievement. Results: In each country, the experimental group achieved better results in mathematics than the control group. At the beginning of the intervention, the achievement gap based on socio-economic status (SES) was equally large in the experimental and the control groups. Only in the experimental group did the achievement gap based on SES become smaller. However, DASI was not found to have an effect on equity when the equity dimension was examined by focusing on the achievement gap based on either gender or ethnicity. Conclusions: Implications of findings are drawn and the importance of measuring equity in terms of student achievement gaps based on different background factors, rather than only on SES, is emphasised. We propose the evaluation of the impact of interventions on promoting equity by the use of various criteria

Is there a vortex-glass transition in high-temperature superconductors?

We show that DC voltage versus current measurements of a YBCO micro-bridge in a magnetic field can be collapsed onto scaling functions proposed by Fisher, Fisher, and Huse, as is widely reported in the literature. We find, however, that good data collapse is achieved for a wide range of critical exponents and temperatures. These results strongly suggest that agreement with scaling alone does not prove the existence of a phase transition. We propose a criterion to determine if the data collapse is valid, and thus if a phase transition occurs. To our knowledge, none of the data reported in the literature meet our criterion.Comment: 4 pages, 4 figure

Empirical estimation of resource constraints for use in model-based economic evaluation: an example of TB services in South Africa.

BACKGROUND: Evidence on the relative costs and effects of interventions that do not consider 'real-world' constraints on implementation may be misleading. However, in many low- and middle-income countries, time and data scarcity mean that incorporating health system constraints in priority setting can be challenging. METHODS: We developed a 'proof of concept' method to empirically estimate health system constraints for inclusion in model-based economic evaluations, using intensified case-finding strategies (ICF) for tuberculosis (TB) in South Africa as an example. As part of a strategic planning process, we quantified the resources (fiscal and human) needed to scale up different ICF strategies (cough triage and WHO symptom screening). We identified and characterised three constraints through discussions with local stakeholders: (1) financial constraint: potential maximum increase in public TB financing available for new TB interventions; (2) human resource constraint: maximum current and future capacity among public sector nurses that could be dedicated to TB services; and (3) diagnostic supplies constraint: maximum ratio of Xpert MTB/RIF tests to TB notifications. We assessed the impact of these constraints on the costs of different ICF strategies. RESULTS: It would not be possible to reach the target coverage of ICF (as defined by policy makers) without addressing financial, human resource and diagnostic supplies constraints. The costs of addressing human resource constraints is substantial, increasing total TB programme costs during the period 2016-2035 by between 7% and 37% compared to assuming the expansion of ICF is unconstrained, depending on the ICF strategy chosen. CONCLUSIONS: Failure to include the costs of relaxing constraints may provide misleading estimates of costs, and therefore cost-effectiveness. In turn, these could impact the local relevance and credibility of analyses, thereby increasing the risk of sub-optimal investments

Hysteretic behavior of the vortex lattice at the onset of the second peak for HgBa2_2CuO4+δ_{4+\delta} superconductor

By means of local Hall probe ac and dc permeability measurements we investigated the phase diagram of vortex matter for the HgBa$_2$CuO$_{4+\delta }$ superconductor in the regime near the critical temperature. The second peak line, $H_{\rm sp}$, in contrast to what is usually assumed, doesn't terminate at the critical temperature. Our local ac permeability measurements revealed pronounced hysteretic behavior and thermomagnetic history effects near the onset of the second peak, giving evidence for a phase transition of vortex matter from an ordered qausilattice state to a disordered glass

Phase diagrams of flux lattices with disorder

We review the prediction, made in a previous work [Phys. Rev. B 52 (1995)], that the phase diagram of type II superconductors consists of a topologically ordered Bragg glass phase at low fields undergoing a transition at higher fields into a vortex glass or a liquid. We estimate the position of the phase boundary using a Lindemann criterion. We find that the proposed phenomenology is compatible with recent experiments on superconductors.Comment: 7 pages 2 figures, uses epsfi

Kinetic Theory of Flux Line Hydrodynamics:LIQUID Phase with Disorder

We study the Langevin dynamics of flux lines of high--T$_c$ superconductors in the presence of random quenched pinning. The hydrodynamic theory for the densities is derived by starting with the microscopic model for the flux-line liquid. The dynamic functional is expressed as an expansion in the dynamic order parameter and the corresponding response field. We treat the model within the Gaussian approximation and calculate the dynamic structure function in the presence of pinning disorder. The disorder leads to an additive static peak proportional to the disorder strength. On length scales larger than the line static transverse wandering length and at long times, we recover the hydrodynamic results of simple frictional diffusion, with interactions additively renormalizing the relaxational rate. On shorter length and time scales line internal degrees of freedom significantly modify the dynamics by generating wavevector-dependent corrections to the density relaxation rate.Comment: 61 pages and 6 figures available upon request, plain TEX using Harvard macro

First order phase transition of the vortex lattice in twinned YBa2Cu3O7 single crystals in tilted magnetic fields

We present an exhaustive analysis of transport measurements performed in twinned YBa2Cu3O7 single crystals which stablishes that the vortex solid-liquid transition is first order when the magnetic field H is applied at an angle theta away from the direction of the twin planes. We show that the resistive transitions are hysteretic and the V-I curves are non-linear, displaying a characteristic s-shape at the melting line Hm(T), which scales as epsilon(theta)Hm(T,theta). These features are gradually lost when the critical point H*(theta) is approached. Above H*(theta) the V-I characteristics show a linear response in the experimentally accessible V-I window, and the transition becomes reversible. Finally we show that the first order phase transition takes place between a highly correlated vortex liquid in the field direction and a solid state of unknown symmetry. As a consequence, the available data support the scenario for a vortex-line melting rather than a vortex sublimation as recently suggested [T.Sasagawa et al. PRL 80, 4297 (1998)].Comment: 10 pages, 8 figures, submitted to PR

Elastic theory of flux lattices in presence of weak disorder

The effect of disorder on flux lattices at equilibrium is studied quantitatively in the absence of free dislocations using both the Gaussian variational method and the renormalization group. Our results for the mean square relative displacements clarify the nature of the crossovers with distance. We find three regimes: (i) a short distance regime (``Larkin regime'') where elasticity holds (ii) an intermediate regime (``Random Manifold'') where vortices are pinned independently (iii) a large distance, quasi-ordered regime where the periodicity of the lattice becomes important and there is universal logarithmic growth of displacements for $2<d<4$ and persistence of algebraic quasi-long range translational order. The functional renormalization group to $O(\epsilon=4-d)$ and the variational method, agree within $10\%$ on the value of the exponent. In $d=3$ we compute the crossover function between the three regimes. We discuss the observable signature of this crossover in decoration experiments and in neutron diffraction experiments on flux lattices. Qualitative arguments are given suggesting the existence for weak disorder in $d=3$ of a `` Bragg glass '' phase without free dislocations and with algebraically divergent Bragg peaks. In $d=1+1$ both the variational method and the Cardy-Ostlund renormalization group predict a glassy state below the same transition temperature $T=T_c$, but with different behaviors. Applications to $d=2+0$ systems and experiments on magnetic bubbles are discussed.Comment: 59 pages; RevTeX 3.0; 5 postscript figures uuencode

Antiepileptic drugs’ tolerability and safety – a systematic review and meta-analysis of adverse effects in dogs

<p>Various anti-epileptic drugs (AEDs) are used for the management of idiopathic epilepsy (IE) in dogs. Their safety profile is an important consideration for regulatory bodies, owners and prescribing clinicians. However, information on their adverse effects still remains limited with most of it derived from non-blinded non-randomized uncontrolled trials and case reports.</p><p><span>This poster won third place, which was presented at the Veterinary Evidence Today conference, Edinburgh November 1-3, 2016. </span></p><br /> <img src="https://www.veterinaryevidence.org/rcvskmod/icons/oa-icon.jpg" alt="Open Access" /