Achieving Results Through Community School Partnerships

Outlines the importance of and strategies for building and maintaining successful partnerships for community schools that integrate academics, youth development, family support, health and social services, and community development. Makes recommendations

Renormalization in theories with modified dispersion relations: weak gravitational fields

We consider a free quantum scalar field satisfying modified dispersion relations in curved spacetimes, within the framework of Einstein-Aether theory. Using a power counting analysis, we study the divergences in the adiabatic expansion of and , working in the weak field approximation. We show that for dispersion relations containing up to $2s$ powers of the spatial momentum, the subtraction necessary to renormalize these two quantities on general backgrounds depends on $s$ in a qualitatively different way: while becomes convergent for a sufficiently large value of $s$, the number of divergent terms in the adiabatic expansion of increases with $s$. This property was not apparent in previous results for spatially homogeneous backgrounds.Comment: 12 pages, no figure

Renewable build-up pathways for the US: Generation costs are not system costs

The transition to a future electricity system based primarily on wind and solar PV is examined for all regions in the contiguous US. We present optimized pathways for the build-up of wind and solar power for least backup energy needs as well as for least cost obtained with a simplified, lightweight model based on long-term high resolution weather-determined generation data. In the absence of storage, the pathway which achieves the best match of generation and load, thus resulting in the least backup energy requirements, generally favors a combination of both technologies, with a wind/solar PV energy mix of about 80/20 in a fully renewable scenario. The least cost development is seen to start with 100% of the technology with the lowest average generation costs first, but with increasing renewable installations, economically unfavorable excess generation pushes it toward the minimal backup pathway. Surplus generation and the entailed costs can be reduced significantly by combining wind and solar power, and/or absorbing excess generation, for example with storage or transmission, or by coupling the electricity system to other energy sectors.Comment: 11 pages, 6 figure

Cosmological Particle Creation in the Presence of Lorentz Violation

In recent years, the effects of Lorentz symmetry breaking in cosmology has attracted considerable amount of attention. In cosmological context several topics can be affected by Lorentz violation,e.g., inflationary scenario, CMB, dark energy problem and barryogenesis. In this paper we consider the cosmological particle creation due to Lorentz violation (LV). We consider an exactly solvable model for finding the spectral properties of particle creation in an expanding space-time exhibiting Lorentz violation. In this model we calculate the spectrum and its variations with respect to the rate and the amount of space-time expansion.Comment: 6 pages, 6 figures, To appear in Physics Letters

Trans-Planckian Dark Energy?

It has recently been proposed by Mersini et al. 01, Bastero-Gil and Mersini 02 that the dark energy could be attributed to the cosmological properties of a scalar field with a non-standard dispersion relation that decreases exponentially at wave-numbers larger than Planck scale (k_phys > M_Planck). In this scenario, the energy density stored in the modes of trans-Planckian wave-numbers but sub-Hubble frequencies produced by amplification of the vacuum quantum fluctuations would account naturally for the dark energy. The present article examines this model in detail and shows step by step that it does not work. In particular, we show that this model cannot make definite predictions since there is no well-defined vacuum state in the region of wave-numbers considered, hence the initial data cannot be specified unambiguously. We also show that for most choices of initial data this scenario implies the production of a large amount of energy density (of order M_Planck^4) for modes with momenta of order M_Planck, far in excess of the background energy density. We evaluate the amount of fine-tuning in the initial data necessary to avoid this back-reaction problem and find it is of order H/M_Planck. We also argue that the equation of state of the trans-Planckian modes is not vacuum-like. Therefore this model does not provide a suitable explanation for the dark energy.Comment: RevTeX - 15 pages, 7 figures: final version to appear in PRD, minor changes, 1 figure adde

Dynamics of Chaotic Inflation with Variable Space Dimension

Within the framework of a model Universe with variable space dimension, we study chaotic inflation with the potential $m^2\phi^2/2$, and calculate the dynamical solutions of the inflaton field, variable space dimension, scale factor, and their interdependence during the inflationary epoch. We show that the characteristic of the variability of the space dimension causes the inflationary epoch in the variable space dimension to last longer than the inflationary epoch in the constant space dimension.Comment: 16 pages, accepted in Phys. Lett.

Taxing food: implications for public health nutrition

AIM: To set out a policy analysis of food taxes as a way of influencing food consumption and behaviour. DESIGN: The study draws on examples of food taxes from the developed world imposed at national and local levels. Studies were identified from a systemised search in six databases with criteria designed to identity articles of policy relevance. RESULTS: The dominant approach identified from the literature was the imposition of food taxes on food to raise general revenue, such as Value Added Tax in the European Union. Food taxes can be applied in various ways, ranging from attempts to directly influence behaviour to those which collect taxes for identified campaigns on healthy eating through to those applied within closed settings such as schools. There is a case for combining taxes of unhealthy foods with subsidies of healthy foods. The evidence from the literature concerning the use and impact of food taxes on food behaviour is not clear and those cases identified are mainly retrospective descriptions of the process. Many food taxes have been withdrawn after short periods of time due to industry lobbying. CONCLUSIONS FOR POLICY: Small taxes with the clear purpose of promoting the health of key groups, e.g. children, are more likely to receive public support. The focus of many tax initiatives is unclear; although they are generally aimed at consumers, another focus could be food manufacturers, using taxes and subsidies to encourage the production of healthier foods, which could have an effect at a population level. Further consideration needs to be given to this aspect of food taxes. Taxing food (and subsidies) can influence food behaviour within closed systems such as schools and the workplace

The History of Lincoln High School

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Quantum metric fluctuations and Hawking radiation

In this Letter we study the gravitational interactions between outgoing configurations giving rise to Hawking radiation and in-falling configurations. When the latter are in their ground state, the near horizon interactions lead to collective effects which express themselves as metric fluctuations and which induce dissipation, as in Brownian motion. This dissipation prevents the appearance of trans-Planckian frequencies and leads to a description of Hawking radiation which is very similar to that obtained from sound propagation in condensed matter models.Comment: 4 pages, revte