GEOGRAPHIC INFORMATION SYSTEMS AND APPLIED ECONOMICS: AN INITIAL DISCUSSION OF POTENTIAL APPLICATIONS AND CONTRIBUTIONS

Geographic Information Systems (GIS) are becoming increasingly important to virtually all of the natural and social sciences. Applied economists will find that GIS can make valuable contributions to many of the problems with which they are concerned. Moreover, a great deal of the science behind GIS technology would benefit from the contributions of applied economists. This paper presents some initial suggestions for the ways in which GIS may be important to economics and the GIS related issues concerning which applied economists could provide useful insights.Research and Development/Tech Change/Emerging Technologies,

Photon Pair Production from a Hot Atomic Ensemble in the Diamond Configuration

This thesis discusses four-wave mixing (4WM) in a warm ensemble of rubidium using the diamond configuration level structure. Both classical 4WM and non- classical photon-pair production are investigated. Quantum information science has spawned a great amount of experimental work on the interaction of light with collective modes of excitation in atomic ensem- bles. Plans to build quantum networks and quantum repeaters with atom ensembles take advantage of nonlinear interactions to produce and store non-classical states of light. These technologies will require photon sources that not only generate non- classical light, but also resonant, narrow band light. Here we investigate a system which could be used as such a source. We take advantage of the 4WM interaction in a warm ensemble of Rubidium atoms. Our scheme utilizes the diamond energy level configuration which, in ru- bidium, allows for correlated pairs at telecommunications wavelengths. We start by examining the properties of classical 4WM in the system. We measure the reso- nance structure and see that it can be understood in terms of velocity class selective resonant enhancement and power splitting effects. The efficiency of the process is low and limited by linear absorption of the pumps. Our observations agree with a semi-classical Maxwell-Bloch theoretical treatment. Next we observe pair generation by spontaneous 4WM from the warm ensem- ble. The temporal profile of the cross-correlation function (CCF) for the photons depends on pump-laser power and detuning. This allows us to produce biphotons with controllable spectra. A simple quantum optical theoretical treatment based on linear filtering gives qualitative agreement with the data. We show that the photon pairs are polarization entangled, clearly violating Bell's Inequality. A perturbative quantum optical treatment predicts the polariza- tion state of the pairs and agrees with our measurements. We analyze the photon statistics of the source and find the largest violation of the two beam Cauchy-Schwarz inequality from a warm atomic source yet. We cast the system as a heralded sin- gle photon source at telecommunications wavelengths and see that it is competitive with other systems in terms of spectral brightness

Peltier Controlled Growth of Thin Ice Films in the Laboratory and Advancing the Methodology of Cavity Enhanced Laser Induced Fluorescence

Cavity enhanced laser induced fluorescence (CELIF) is the first technique to combine cavity ring-down (CRDS) and laser induced fluorescence (LIF) spectroscopies in a single beam experiment. It has been shown previously to extend the dynamic range of CRDS to cover six orders of magnitude in total when observing BPEB concentrations seeded in a pulsed molecular beam. This study has extended CELIF to the most general application where a fluorescer or scatterer fills the length of a pulsed CRD experiment. Under these conditions CELIF is found to produce consistently smaller errors than CRD and is competitive with it but does not extend the dynamic range. Observing acetone fluorescence and nitrogen Rayleigh scattering it has been shown how the CRD signal normalises the LIF signal generated and that the normalisation remains linear during changes to the input powers, pressures and detector gains. Furthermore it has been shown it can be used to measure absolute quantum yields of fluorescence using acetone as an example. A peltier based set-up for cooling the upper surface of a prism for the growth of thin ice films at temperatures of the troposphere and stratosphere has been constructed. A full temperature range of 225-303K was displayed. Testing showed the optimal conditions of ice growth to be a rapid expansion directed at the surface. Ice films 2.5-11.8um thick have been successfully grown at 225.2+-0.2K covering, at maximum, 96% of a 1cm by 3cm stainless steel prism surface. During growth a strong migration over time to an area 0.028+-0.002cm^2 was seen caused by a temperature gradient on the surface, dT~5K from the centre to the outside of the surface along its short side. To monitor this and ice growth, two methods have been successfully installed and tested. A morphological analysis combined with video monitoring can accurately determine areas within 5% and a HeNe laser reflected from the ice is able to monitor surface thicknesses from interference patterns. Together these offer a complete method to characterise an ice film over the duration of an experiment

Measuring unmet need for social care among older people

Recent spending cuts in the area of adult social care raise policy concerns about the proportion of older people whose need for social care is not met. Such concerns are emphasised in the context of population ageing and other demographic changes. This briefing summarises research published in Population Trends no. 145 which explores the concept of ‘unmet need’ for Activities of Daily Living (ADLs) and Instrumental Activities of Daily Living (IADLs), using data on the receipt of support (informal, state or privately paid for). The results show that each of the three different support sectors tend to provide help for different kinds of need, and that worryingly, there is a significant level of ‘unmet need’ for certain activities

Lattice thermal expansion and anisotropic displacements in urea, bromomalonic aldehyde, pentachloropyridine and naphthalene

Anisotropic displacement parameters (ADPs) are commonly used in crystallography, chemistry and related fields to describe and quantify thermal motion of atoms. Within the very recent years, these ADPs have become predictable by lattice dynamics in combination with first-principles theory. Here, we study four very different molecular crystals, namely urea, bromomalonic aldehyde, pentachloropyridine, and naphthalene, by first-principles theory to assess the quality of ADPs calculated in the quasi-harmonic approximation. In addition, we predict both thermal expansion and thermal motion within the quasi-harmonic approximation and compare the predictions with experimental data. Very reliable ADPs are calculated within the quasi-harmonic approximation for all four cases up to at least 200 K, and they turn out to be in better agreement with experiment than the harmonic ones. In one particular case, ADPs can even reliably be predicted up to room temperature. Our results also hint at the importance of normal-mode anharmonicity in the calculation of ADPs

Application of Computational Fluid Dynamics (CFD) through project-based learning

This case study has been developed as part of the Engineering Subject Centre Teaching Awards 2010, from data gathered through observations of the teaching component; interviews with the tutor and a student focus group. A Computational Fluid Dynamics (CFD) module was started in the 1990s when many colleagues perceived CFD as too ‘dangerous’ to be taught at undergraduate level. It was usually reserved for postgraduate level study. The tutor, Henk Versteeg, and the department could see the commercial applications of the codes and wanted to introduce the students to some of the software that was being developed. Henk approached the software vendors directly and negotiated educational discounts for the licences