Effect of spin-orbit interaction on a magnetic impurity in the vicinity of a surface

We propose a new mechanism for surface-induced magnetic anisotropy to explain the thickness-dependence of the Kondo resistivity of thin films of dilute magnetic alloys. The surface anisotropy energy, generated by spin-orbit coupling on the magnetic impurity itself, is an oscillating function of the distance d from the surface and decays as 1/d^2. Numerical estimates based on simple models suggest that this mechanism, unlike its alternatives, gives rise to an effect of the desired order of magnitude.Comment: 4 pages, 4 figure

Unfolding Rates for the Diffusion-Collision Model

In the diffusion-collision model, the unfolding rates are given by the likelihood of secondary structural cluster dissociation. In this work, we introduce an unfolding rate calculation for proteins whose secondary structural elements are $\alpha$-helices, modeled from thermal escape over a barrier which arises from the free energy in buried hydrophobic residues. Our results are in good agreement with currently accepted values for the attempt rate.Comment: Shorter version of cond-mat/0011024 accepted for publication in PR

Inspection Across the UK: how the four nations intend to contribute to school improvement

Exploring and comparing the inspection regimes in the four nations of the UK is timely because whilst each country has its own system, new inspection frameworks have been recently introduced in England and will shortly be implemented in other nations such as Wales. Hence, this study critically examines how and under what conditions longstanding and new inspection regimes intend to lead to school improvement. The research questions that guided the study included: 1. What is the theory of change of each of the four inspectorates of education in the four nations of the UK (England, Scotland, Wales, and Northern Ireland (NI))? 2. What are stakeholders’ views of, and experiences with, inspections? The methodology comprised of three phases. Phase 1 reconstructed the programme theory of the inspection framework of each inspectorate of education (Ofsted in England, The Education Training Inspectorate (ETI) in Northern Ireland, Education Scotland (ES) in Scotland and Estyn in Wales) through the analysis of 60 policy documents. Phase 2 validated Phase 1 through engagement with 12 experts. Phase 3 explored the views of, and experiences with, inspections through fieldwork (24 survey and 7 semi-structured interviews) with 31 stakeholders (headteachers, governors, local authority school improvement staff and teachers).The findings capture the similarities and differences across the four inspection frameworks in the UK. The analysis of the four programme theories revealed substantive differences between school inspection regimes across the UK. This study found some convergence in the UK inspectorates’ intended mechanisms or engines through which inspections are supposed to contribute to school improvement, but mostly divergences not only in the mechanisms, but also intended effects (or desired aims) at both the school and system levels. Regarding the system level intended effects, while England promotes social mobility and allows young people to reach their potential, the other regimes put explicit emphasis on all learners or equity: NI fosters an inclusive learning environment where all learners have access to high quality provision; Scotland’s inspection framework aims to promote the highest standards of learning leading to better outcomes for all learners; and Wales aims to create the conditions to support all learners to achieve high standards and strong levels of wellbeing. When school-level intended effects are considered, each inspectorate has a different combination of quality indicators leading to the ‘good’ or above judgement of schools in their nations. The key similarities were that all inspectorates judge school performance focusing on the quality of education/provision/teaching and learning, as well as leadership and management, however with varied emphasis such as Scotland’s ‘leadership of change’. The key difference is the extent to which other indicators are considered (beyond academic performance and leadership) by inspectorates when judging school performance. For example: Scotland’s ‘success and achievement’ considers the progress in raising attainment and achievement by ensuring at the same time wellbeing, equality, and inclusion. Wales focuses explicitly on wellbeing. Wales and NI put a special emphasis on care and support. England addresses ‘personal development’, ‘behaviour and attitudes,’ and is the only inspectorate that explicitly aims to reduce the unintended consequences of inspections, such as gaming and off-rolling. Although every nation wants to strike the right balance between external evaluation and self-evaluation to ultimately enhance school improvement through inspection, there are also clear differences in the intended mechanisms (or how) to improve schools across the UK. We found that the main similarities to support school improvement were: Giving feedback through inspection in England, Wales, and NI Promoting school self-evaluation in Scotland, Wales, and NI Enhancing professional dialogue/in-depth professional discussions/school self-reflection culture in Scotland and NI The main differences in how inspectorates are expected to support school improvement were: Preventing bad practice from becoming entrenched in England Promoting openness and transparency about the processes and instruments in NI Focusing on the mechanisms (or engines) that the inspectorates implement in order to improve the system level, the main similarities were: Providing system level feedback to inform national policy planning in the four nations Delivering public accountability/assurance and report to different stakeholders (i.e. parents) in the four nations Building capacity by including practitioners in inspection teams in England, Scotland and Wales Enhancing system-wide learning from good practice in England and Wales The main differences in how inspectorates expect to support system level improvement were: Promoting collective engagement, learning and collaboration in Scotland Reducing regulatory burdens in England The main findings from the fieldwork conducted with 31 stakeholders (headteachers, governors, LA, school improvement staff and teachers) showed: More compliance than innovation: Stakeholders in the four nations recognised that inspections encouraged more compliance than innovation. They believed that going beyond inspection frameworks held little value, especially when doing so risked taking away time from the quality of education provision/teaching and learning. They prioritised their resources and actions according to the hierarchy communicated through the frameworks, so the main sections were interpreted as areas of policy enforcement, whereas statements (communicated for example in bullet points), were interpreted as less relevant. Pervasive inspection readiness: The four UK inspection frameworks were effectively enacted by stakeholders to such an extent that they were pervasive in the sense that they constrained pedagogical and curriculum innovations beyond the framework. Examples of ‘inspection readiness’ abounded. A two-way ‘contract’ Stakeholders interpreted inspection frameworks as a two-way ‘contract,’ in the sense that they guided the micropolitics of schools, but also applied them to evaluate inspectorates, inspectors, and inspections. Negative experiences tended to be associated with inspectors departing from the inspection framework to follow their own agenda, and vice versa. A gap remains between how inspectorates intend to improve schools, and the way stakeholders interpret frameworks and experience inspections

Dynamics of active membranes with internal noise

We study the time-dependent height fluctuations of an active membrane containing energy-dissipating pumps that drive the membrane out of equilibrium. Unlike previous investigations based on models that neglect either curvature couplings or random fluctuations in pump activities, our formulation explores two new models that take both of these effects into account. In the first model, the magnitude of the nonequilibrium forces generated by the pumps is allowed to fluctuate temporally. In the second model, the pumps are allowed to switch between "on" and "off" states. We compute the mean squared displacement of a membrane point for both models, and show that they exhibit distinct dynamical behaviors from previous models, and in particular, a superdiffusive regime specifically arising from the shot noise.Comment: 7 pages, 4 figure

Metallicity inhomogeneities in local star-forming galaxies as sign of recent metal-poor gas accretion

We measure the oxygen metallicity of the ionized gas along the major axis of seven dwarf star-forming galaxies. Two of them, SDSSJ1647+21 and SDSSJ2238+14, show 0.5 dex metallicity decrements in inner regions with enhanced star-formation activity. This behavior is similar to the metallicity drop observed in a number of local tadpole galaxies by Sanchez Almeida et al. (2013) and interpreted as showing early stages of assembling in disk galaxies, with the star formation sustained by external metal-poor gas accretion. The agreement with tadpoles has several implications: (1) it proves that galaxies other than the local tadpoles present the same unusual metallicity pattern. (2) Our metallicity inhomogeneities were inferred using the direct method, thus discarding systematic errors usually attributed to other methods. (3) Taken together with the tadpole data, our findings suggest a threshold around one tenth the solar value for the metallicity drops to show up. Although galaxies with clear metallicity drops are rare, the physical mechanism responsible for them may sustain a significant part of the star-formation activity in the local Universe. We argue that the star-formation dependence of the mass-metallicity relationship, as well as other general properties followed by most local disk galaxies, are naturally interpreted as side effects of pristine gas infall. Alternatives to the metal poor gas accretion are examined too.Comment: Accepted for publication in ApJ. 10 pages. 5 Fig