Towards the Sustainable University.

noAll universities have the capacity to embrace, embed or ignore sustainable development. Looking across the sector and reflecting on the past seven years and my own institutional experiences, the key finding is that change for campus and curriculum-based sustainability is clearly possible but unpredictable. For many years my own institution (University of Bradford) struggled to make progress in a number of key aspects of `campus greening¿ including recycling, green build, energy management, green travel, fair trade etc. It employed its first environmental manager as recently as 2003. Up until 2007, education for sustainable development (ESD) was largely found in one small academic department. Now, as this paper describes, it is a central feature of the learning and teaching strategy for the university and an overall institutional objective

Evaluation of an equilibrium phase free-breathing dynamic contrast-enhanced MRI prototype sequence compared to traditional breath-held MRI acquisition in liver oncology patients

Introduction: Magnetic Resonance Imaging (MRI) is a commonly used for diagnosing metastatic liver disease. When patients are unable to achieve the necessary arrested respiration required during image acquisition, image artefacts occur that affect image quality and diagnostic value. The main contribution of this study is the evaluation of a novel prototype technique that allows a specific sub-group of patients to breathe freely throughout the acquisition of dynamic contrast enhanced equilibrium phase MRI of the liver. Methods: The study compared a traditional single phase of arrested respiration T1-weighted (T1W) fat saturated (FatSat) volumetric interpolated breath-hold sequence (VIBE) with a novel free-breathing T1W 3D Radial VIBE prototype sequence. A cohort of patients (n=30) with known hepatic metastases who demonstrated difficulty in complying with the instructions for arrested inspiration were scanned. Both sets of data were compared for diagnostic quality using a Likert scale questionnaire by specialist Oncology Radiologists (n=2). Results: Higher scores for all image quality criteria, including the presence of artefact (2.6 + 0.57; p <0.001), lesion conspicuity (2.9 + 0.35; p <0.001) and visibility of intra-hepatic vessels (2.8 + 0.37; p <0.001) were found using the free-breathing sequence (13.5 + 1.94; p <0.001 t=13.31; df 29; p <0.001) than the breath hold phase (8.1 + 2.06), confirmed with kappa (k-0.023; p-0.050). Conclusions: The results demonstrated a 39.5% improvement in overall image quality using the T1W 3D Radial VIBE prototype sequence, and has the potential to improve patient experience and reduce image artefacts during MRI imaging of this sub-group of patients

New Approaches to Traffic Management Solution – With Reference to Sowerby Bridge

BACKGROUND This study was commissioned by the Civic Trust to identify new approaches to traffic management solutions for Sowerby Bridge. The objective of the overall study was to identify low cost, innovative solutions to problems created by high volumes of traffic using the A58. This road is the main shopping street in Sowerby Bridge. In our brief it was stressed that any new road construction, such as a by-pass, was not a feasible or acceptable solution due to the severe vertical gradients surrounding Sowerby Bridge. The town is on the brink of a major programme of regeneration. A nationally important canoe slalom course has been created, the riverside mill area fronting onto the River Calder is being developed for commercial and leisure use, and there is a proposal to reopen the Rochdale Canal. In view of this it is essential to ensure that traffic on the A58 is managed so as to minimise its effect on the environment and trade, without adversely affecting local access. In writing our report we have separated the problem and solution identification stages. The solution identification stage is reported in Working Paper 263 (Hopkinson et al 1988b). The final stage of our study, which involves presenting our final solutions back to the users of Sowerby Bridge for comment, is to be reported in a forthcoming report, WP 265 (Hopkinson et al, 1988c)

Modelling Gaia CCD pixels with Silvaco 3D engineering software

Gaia will only achieve its unprecedented measurement accuracy requirements with detailed calibration and correction for radiation damage. We present our Silvaco 3D engineering software model of the Gaia CCD pixel and two of its applications for Gaia: (1) physically interpreting supplementary buried channel (SBC) capacity measurements (pocket-pumping and first pixel response) in terms of e2v manufacturing doping alignment tolerances; and (2) deriving electron densities within a charge packet as a function of the number of constituent electrons and 3D position within the charge packet as input to microscopic models being developed to simulate radiation damage.Comment: 4 pages, 3 figures, contributed poster, appearing in proceedings of the ELSA conference: Gaia, at the frontiers of astrometry, 7-11 June 2010, S\`evres, Pari

Excess noise characteristics of Al0.8Ga0.2As avalanche photodiodes

The avalanche noise characteristics of Al0.8Ga0.2 As have been measured in a range of p-i-n and n-i-p diodes with i-region widths ω varying from 1.02 to 0.02 μm. While thick bulk diodes exhibit low excess noise from electron initiated multiplication, owing to the large α/β ratio (1/k), the excess noise of diodes with ω < 0.31 μm were found to be greatly reduced by the effects of dead space. The thinnest diodes exhibit very low excess noise, corresponding to k = 0.08, up to a multiplication value of 90. In contrast to most III-V materials, it was found that both thick and thin Al0.8Ga0.2As multiplication layers can give very low excess noise and that electrons must initiate multiplication to minimize excess noise, even in thin structure

Digging supplementary buried channels: investigating the notch architecture within the CCD pixels on ESA's Gaia satellite

The European Space Agency (ESA) Gaia satellite has 106 CCD image sensors which will suffer from increased charge transfer inefficiency (CTI) as a result of radiation damage. To aid the mitigation at low signal levels, the CCD design includes Supplementary Buried Channels (SBCs, otherwise known as `notches') within each CCD column. We present the largest published sample of Gaia CCD SBC Full Well Capacity (FWC) laboratory measurements and simulations based on 13 devices. We find that Gaia CCDs manufactured post-2004 have SBCs with FWCs in the upper half of each CCD that are systematically smaller by two orders of magnitude (<50 electrons) compared to those manufactured pre-2004 (thousands of electrons). Gaia's faint star (13 < G < 20 mag) astrometric performance predictions by Prod'homme et al. and Holl et al. use pre-2004 SBC FWCs as inputs to their simulations. However, all the CCDs already integrated onto the satellite for the 2013 launch are post-2004. SBC FWC measurements are not available for one of our five post-2004 CCDs but the fact it meets Gaia's image location requirements suggests it has SBC FWCs similar to pre-2004. It is too late to measure the SBC FWCs onboard the satellite and it is not possible to theoretically predict them. Gaia's faint star astrometric performance predictions depend on knowledge of the onboard SBC FWCs but as these are currently unavailable, it is not known how representative of the whole focal plane the current predictions are. Therefore, we suggest Gaia's initial in-orbit calibrations should include measurement of the onboard SBC FWCs. We present a potential method to do this. Faint star astrometric performance predictions based on onboard SBC FWCs at the start of the mission would allow satellite operating conditions or CTI software mitigation to be further optimised to improve the scientific return of Gaia.Comment: Accepted for publication in MNRAS, 16 pages, 19 figure

Simulating CCDs for the Chandra Advanced CCD Imaging Spectrometer

We have implemented a Monte Carlo algorithm to model and predict the response of various kinds of CCDs to X-ray photons and minimally-ionizing particles and have applied this model to the CCDs in the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer. This algorithm draws on empirical results and predicts the response of all basic types of X-ray CCD devices. It relies on new solutions of the diffusion equation, including recombination, to predict the radial charge cloud distribution in field-free regions of CCDs. By adjusting the size of the charge clouds, we can reproduce the event grade distribution seen in calibration data. Using a model of the channel stops developed here and an insightful treatment of the insulating layer under the gate structure developed at MIT, we are able to reproduce all notable features in ACIS calibration spectra. The simulator is used to reproduce ground and flight calibration data from ACIS, thus confirming its fidelity. It can then be used for a variety of calibration tasks, such as generating spectral response matrices for spectral fitting of astrophysical sources, quantum efficiency estimation, and modeling of photon pile-up.Comment: 42 pages, 22 figures; accepted for publication in Nuclear Instruments and Methods in Physics Research, Section A; paper with high-quality figures can be found at ftp://ftp.astro.psu.edu/pub/townsley/simulator.p

Fuels treatment and wildfire effects on runoff from Sierra Nevada mixed-conifer forests

We applied an eco-hydrologic model (Regional Hydro-Ecologic Simulation System [RHESSys]), constrained with spatially distributed field measurements, to assess the impacts of forest-fuel treatments and wildfire on hydrologic fluxes in two Sierra Nevada firesheds. Strategically placed fuels treatments were implemented during 2011–2012 in the upper American River in the central Sierra Nevada (43 km2) and in the upper Fresno River in the southern Sierra Nevada (24 km2). This study used the measured vegetation changes from mechanical treatments and modelled vegetation change from wildfire to determine impacts on the water balance. The well-constrained headwater model was transferred to larger catchments based on geologic and hydrologic similarities. Fuels treatments covered 18% of the American and 29% of the Lewis catchment. Averaged over the entire catchment, treatments in the wetter central Sierra Nevada resulted in a relatively light vegetation decrease (8%), leading to a 12% runoff increase, averaged over wet and dry years. Wildfire with and without forest treatments reduced vegetation by 38% and 50% and increased runoff by 55% and 67%, respectively. Treatments in the drier southern Sierra Nevada also reduced the spatially averaged vegetation by 8%, but the runoff response was limited to an increase of less than 3% compared with no treatment. Wildfire following treatments reduced vegetation by 40%, increasing runoff by 13%. Changes to catchment-scale water-balance simulations were more sensitive to canopy cover than to leaf area index, indicating that the pattern as well as amount of vegetation treatment is important to hydrologic response