7,688 research outputs found

    Building Firm Foundations Sure Start Mellow Valley Evaluation Report 2005/ 2006

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    This report forms the Year 3 annual report. Alongside documenting findings from Year 2 evaluation activities, this report also brings together findings from previous evaluation activities and gives wider consideration to the overall progress and outcomes of the programme so far. Section two explains the evaluation approach that has been adopted and details the activities that have been conducted and the methods used. Section 3 highlights the key themes and findings to emerge from the workshops undertaken with the Sure Start teams and provides a summary of the indepth evaluation conducted of the Family Support Team. Section 4 is entitled ‘Pulling it all together’ and considers the work and achievements of Sure Start Mellow Valley with particular regard to the five outcomes of Every Child Matters. A conclusion and brief summary of findings is found in Section 5 followed by a range of further information within the Section 6 Appendices

    SAR antenna calibration techniques

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    Calibration of SAR antennas requires a measurement of gain, elevation and azimuth pattern shape, boresight error, cross-polarization levels, and phase vs. angle and frequency. For spaceborne SAR antennas of SEASAT size operating at C-band or higher, some of these measurements can become extremely difficult using conventional far-field antenna test ranges. Near-field scanning techniques offer an alternative approach and for C-band or X-band SARs, give much improved accuracy and precision as compared to that obtainable with a far-field approach

    A weak turbulence theory for incompressible magnetohydrodynamics

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    We derive a weak turbulence formalism for incompressible magnetohydrodynamics. Three-wave interactions lead to a system of kinetic equations for the spectral densities of energy and helicity. The kinetic equations conserve energy in all wavevector planes normal to the applied magnetic field B0ê[parallel R: parallel]. Numerically and analytically, we find energy spectra E± [similar] kn±[bot bottom], such that n+ + n− = −4, where E± are the spectra of the Elsässer variables z± = v ± b in the two-dimensional case (k[parallel R: parallel] = 0). The constants of the spectra are computed exactly and found to depend on the amount of correlation between the velocity and the magnetic field. Comparison with several numerical simulations and models is also made

    Norman Julius Zabusky OBITUARY

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    Norman Julius Zabusky, who laid the foundations for several critical advancements in nonlinear science and experimental mathematics, died of idiopathic pulmonary fibrosis on 5 February 2018 in Beersheba, Israel. He also made fundamental contributions to computational fluid dynamics and advocated the importance of visualization in science.Published versio

    Systematic derivation of a rotationally covariant extension of the 2-dimensional Newell-Whitehead-Segel equation

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    An extension of the Newell-Whitehead-Segel amplitude equation covariant under abritrary rotations is derived systematically by the renormalization group method.Comment: 8 pages, to appear in Phys. Rev. Letters, March 18, 199

    Balancing Cost and Emissions Certainty: An Allowance Reserve for Cap-and-Trade

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    On efficiency grounds, the economics community has to date tended to emphasize price-based policies to address climate change -- such as taxes or a “safety-valve” price ceiling for cap-and-trade -— while environmental advocates have sought a more clear quantitative limit on emissions. This paper presents a simple modification to the idea of a safety valve -- a quantitative limit that we call the allowance reserve. Importantly, this idea may bridge the gap between competing interests and potentially improve efficiency relative to tax or other price-based policies. The last point highlights the deficiencies in several previous studies of price and quantity controls for climate change that do not adequately capture the dynamic opportunities within a cap-and-trade system for allowance banking, borrowing, and intertemporal arbitrage in response to unfolding information.climate change, regulation, uncertainty, welfare, prices, quantities

    Finite time collapse of N classical fields described by coupled nonlinear Schrodinger equations

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    We prove the finite-time collapse of a system of N classical fields, which are described by N coupled nonlinear Schrodinger equations. We derive the conditions under which all of the fields experiences this finite-time collapse. Finally, for two-dimensional systems, we derive constraints on the number of particles associated with each field that are necessary to prevent collapse.Comment: v2: corrected typo on equation

    Square Patterns and Quasi-patterns in Weakly Damped Faraday Waves

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    Pattern formation in parametric surface waves is studied in the limit of weak viscous dissipation. A set of quasi-potential equations (QPEs) is introduced that admits a closed representation in terms of surface variables alone. A multiscale expansion of the QPEs reveals the importance of triad resonant interactions, and the saturating effect of the driving force leading to a gradient amplitude equation. Minimization of the associated Lyapunov function yields standing wave patterns of square symmetry for capillary waves, and hexagonal patterns and a sequence of quasi-patterns for mixed capillary-gravity waves. Numerical integration of the QPEs reveals a quasi-pattern of eight-fold symmetry in the range of parameters predicted by the multiscale expansion.Comment: RevTeX, 11 pages, 8 figure
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