789 research outputs found

    Home-Grown Cell Implicated in Plot

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    Many of the early details of the alleged terror plot that unraveled in London Thursday echoed warnings that terrorism experts have repeated for the last five years: Al Qaeda and like-minded groups remain dangerous, are determined to exceed the devastation wrought in the Sept. 11 attacks and retain a near-obsession on using airplanes, one way or another, as weapons. All of those predictions appeared to have been borne out by Thursday's events, with one significant exception. The fact that such a massive, seemingly sophisticated terror scheme was apparently laid by a homegrown group of British citizens traveling on legal passports rather than by hard-core foreign jihadists infilrating Western countries

    Collective Charge Fluctuations in Single-Electron Processes on Nano-Networks

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    Using numerical modeling we study emergence of structure and structure-related nonlinear conduction properties in the self-assembled nanoparticle films. Particularly, we show how different nanoparticle networks emerge within assembly processes with molecular bio-recognition binding. We then simulate the charge transport under voltage bias via single-electron tunnelings through the junctions between nanoparticles on such type of networks. We show how the regular nanoparticle array and topologically inhomogeneous nanonetworks affect the charge transport. We find long-range correlations in the time series of charge fluctuation at individual nanoparticles and of flow along the junctions within the network. These correlations explain the occurrence of a large nonlinearity in the simulated and experimentally measured current-voltage characteristics and non-Gaussian fluctuations of the current at the electrode.Comment: 10 pages, 7 figure

    Modelling the evaporation of thin films of colloidal suspensions using Dynamical Density Functional Theory

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    Recent experiments have shown that various structures may be formed during the evaporative dewetting of thin films of colloidal suspensions. Nano-particle deposits of strongly branched `flower-like', labyrinthine and network structures are observed. They are caused by the different transport processes and the rich phase behaviour of the system. We develop a model for the system, based on a dynamical density functional theory, which reproduces these structures. The model is employed to determine the influences of the solvent evaporation and of the diffusion of the colloidal particles and of the liquid over the surface. Finally, we investigate the conditions needed for `liquid-particle' phase separation to occur and discuss its effect on the self-organised nano-structures

    Nonequilibrium dynamics of fully frustrated Ising models at T=0

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    We consider two fully frustrated Ising models: the antiferromagnetic triangular model in a field of strength, h=HTkBh=H T k_B, as well as the Villain model on the square lattice. After a quench from a disordered initial state to T=0 we study the nonequilibrium dynamics of both models by Monte Carlo simulations. In a finite system of linear size, LL, we define and measure sample dependent "first passage time", trt_r, which is the number of Monte Carlo steps until the energy is relaxed to the ground-state value. The distribution of trt_r, in particular its mean value, , is shown to obey the scaling relation, L2ln(L/L0) \sim L^2 \ln(L/L_0), for both models. Scaling of the autocorrelation function of the antiferromagnetic triangular model is shown to involve logarithmic corrections, both at H=0 and at the field-induced Kosterlitz-Thouless transition, however the autocorrelation exponent is found to be HH dependent.Comment: 7 pages, 8 figure

    Please mind the gap: students’ perspectives of the transition in academic skills between A-level and degree level geography

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    This paper explores first-year undergraduates’ perceptions of the transition from studying geography at pre-university level to studying for a degree. This move is the largest step students make in their education, and the debate about it in the UK has been reignited due to the government’s planned changes to A-level geography. However, missing from most of this debate is an appreciation of the way in which geography students themselves perceive their transition to university. This paper begins to rectify this absence. Using student insights, we show that their main concern is acquiring the higher level skills required for university learning

    The politics of the teaching of reading

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    Historically, political debates have broken out over how to teach reading in primary schools and infant classrooms. These debates and “reading wars” have often resulted from public concerns and media reportage of a fall in reading standards. They also reflect the importance placed on learning to read by parents, teachers, employers, and politicians. Public and media-driven controversies over the teaching of reading have resulted in intense public and professional debates over which specific methods and materials to use with beginning readers and with children who have reading difficulties. Recently, such debates have led to a renewed emphasis on reading proficiency and “standardized” approaches to teaching reading and engaging with literacy. The universal acceptance of the importance of learning to read has also led to vested interests in specific methods, reading programmes, and early literacy assessments amongst professional, business, commercial, and parental lobbying groups. This article traces these debates and the resulting growing support for a quantitative reductionist approach to early-reading programmes
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