Edible High Town: Assessing the value of urban community gardens.

This report is the joint product of evaluation by a London South Bank University academic (Dr Barbara Czarnecka) and Edible High Town coordinator (Konni Deppe). This report presents an evaluation of an urban community gardening initiative, Edible High Town. Community gardens, including urban community gardens such as Edible High Town, involve: “the communal cultivation of plants, varying in form according to local contexts and the needs and desires of gardening spaces and local residents. It includes collective gardening undertaken for community development, food production, health promotion, horticultural therapy, collective action, and environmental and permaculture education.” In the past, urban community gardens have been identified as providing a model for promoting sustainable urban living. At present, community gardens, especially those located in deprived urban areas such as High Town in Luton, have been used as a public health tool to foster particular health outcomes related to healthy eating, mental health and physical exercise. Moreover, such gardens are also seen as initiatives that contribute to community cohesion by cultivating connections between neighbours and contributing to the regeneration of deprived areas and hence improving the well-being of residents. Hence, this evaluation focuses on assessing the social, health, economic, and environmental benefits of Edible High Town initiative. The report is divided into the following sections: 1) What is Edible High Town? 2) How did we evaluate Edible High Town? Evaluation framework and evaluation methodology; 3) Evaluation results; and 4) Recommendations and conclusion

Quantum dot photonic crystal lasers

Coupled cavity designs on two-dimensional square lattice photonic crystal slabs were used to demonstrate optically pumped indium arsenide quantum dot photonic crystal lasers at room temperature. Threshold pump powers of 120 and 370 μW were observed for coupled cavities including two and four defect cavities defined in optimised photonic crystals

Critical Collapse in Einstein-Gauss-Bonnet Gravity in Five and Six Dimensions

Einstein-Gauss-Bonnet gravity (EGB) provides a natural higher dimensional and higher order curvature generalization of Einstein gravity. It contains a new, presumably microscopic, length scale that should affect short distance properties of the dynamics, such as Choptuik scaling. We present the results of a numerical analysis in generalized flat slice co-ordinates of self-gravitating massless scalar spherical collapse in five and six dimensional EGB gravity near the threshold of black hole formation. Remarkably, the behaviour is universal (i.e. independent of initial data) but qualitatively different in five and six dimensions. In five dimensions there is a minimum horizon radius, suggestive of a first order transition between black hole and dispersive initial data. In six dimensions no radius gap is evident. Instead, below the GB scale there is a change in the critical exponent and echoing period.Comment: 21 pages, 39 figures, a couple of references and two new figures adde

Scanning a photonic crystal slab nanocavity by condensation of xenon

Allowing xenon or nitrogen gas to condense onto a photonic crystal slab nanocavity maintained at 10–20 K results in shifts of the nanocavity mode wavelength by as much as 5 nm (~=4 meV). This occurs in spite of the fact that the mode defect is achieved by omitting three holes to form the spacer. This technique should be useful in changing the detuning between a single quantum dot transition and the nanocavity mode for cavity quantum electrodynamics experiments, such as mapping out a strong coupling anticrossing curve. Compared with temperature scanning, it has a much larger scan range and avoids phonon broadening

High spontaneous emission coupling factor in photonic crystal nanolasers

We have demonstrated high spontaneous emission coupling factor ~ 0.1 from photonic crystal nanolasers with quantum dots. This high coupling resulted from narrow homogenous broadening of the quantum dots and the small number of resonances

Design and characterization of quantum dot photonic crystal lasers

Quantum dot photonic crystal lasers are demonstrated at room temperature by optical pulse pumping. Coupled cavities were designed based on square lattice PC slabs. Optimized two-dimensional photonic crystal cavities were defined in 200nm slabs with five-stacked InAS QDs layers. The two- and four-coupled cavities showed as incident pump power threshold as 120μW and 370μW, respectively, both from QD ground state emission range. Both clear threshold in pump power-output resonance power and resonance line width narrowing were observed from our membrane samples. The measured wavelengths matched very well with wavelengths predicted by 3D-Finite Difference Time Domain modelling