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Artificial neural networks for mapping regional-scale upland vegetation from high spatial resolution imagery
No full textUpland vegetation represents an important resource that requires frequent monitoring. However, the heterogeneous nature of upland vegetation and lack of ground data require classification techniques that have a high degree of generalization ability. This study investigates the use of artificial neural networks as a means of mapping upland vegetation from remotely sensed data. First, the optimum size of support to map upland vegetation was estimated as being less than 4m, which suggested that soft classification techniques and high spatial resolution IKONOS imagery were required. The use of high spatial resolution imagery for regional-scale areas has introduced new challenges to the remote sensing community, such as using limited ground data and mapping land-cover dynamics and variation over large areas. This work then investigated the utility of artificial neural networks ( ANN) for regional-scale upland vegetation from IKONOS imagery using limited ground data and to map unseen data from remote geographical locations. A Multiple Layer Perceptron was trained with pixels from an IKONOS image using early stopping; however, despite high classification accuracies when calculated for pixels from an area where training pixels were extracted, the networks did not produce high accuracies when applied to unseen data from a remote area
Probing localized states distributions in semiconductors by Laplace transform transient photocurrent spectroscopy
No full textWe report on the effectiveness of two methods for recovering the density of electronic states from transient photocurrent data, one employing an exact solution of the Laplace transformed multiple-trapping rate equations and one a Tikhonov regularization technique. In order to evaluate these methods for recovery of energetically broad and narrower distributions of states we have applied each to data obtained from plasma-enhanced chemical vapor deposition (PECVD) a-Si:H films subjected to progressive light soaking and also to a single crystal sample of tin-doped crystalline CdTe. Both methods are found to perform equally well in terms of accuracy and resolution but the exact method is more sensitive to noise on the input data. A featureless increase in defect density in the PECVD a-Si:H film of a factor of 5–10 is observed on light soaking. Preliminary analysis of the CdTe:Sn data indicates the presence of two narrow bands of states, approximately 0.15 and 0.36 eV below the conduction band edge
Defining the Energy Efficiency Design Envelope for Regional Scottish Passivhaus Dwellings
No full textThe aim of this research is to achieve regional solutions to Passivhaus (PH) in Scotland by quantifying the effects of varying key architectural parameters on the energy performance of three prototype house typologies across the different climate data regions. It uses PHPP to generate weather optimisation graphs for glazing area, but expands the variables to include; orientation, typology and roof form. It investigates; detached, semi-detached and mid-terrace housing typologies, altering a number of architectural variables in each case. A four bedroom prototype house design is used based on passive solar principles and specified to comply with a space heating energy demand of under 15 kWh/(m²a) in four Scottish climates and a heating load of under 10 W/m² in two further climate regions. The study investigates the effects on the Specific Space Heat Demand of the prototype design when changing key variables: orientation, area of north and south facing glazing, roof pitch and building form. The results showed marked differences in the thermal performance of the prototype across the seven different climate data regions reflecting the range of climate extremes and their impact on the architectural design. It begins to develop an understanding of the extent to which the different architectural criteria modelled impact on the energy efficiency of the house and the degree to which these can be varied whilst still meeting Passivhaus compliance benchmarks. The study illustrates the need for more nuanced regional solutions to ultra low energy housing in Scotland that better reflects the large regional climatic differences across the country
OPEC Production Management Practices under WTO Law and the Antitrust Law of Non-OPEC Countries
No full textThe petroleum production management practices of OPEC member states have always been controversial particularly among the major petroleum-consuming nations of the developed world. While this controversy has traditionally been kept within the realm of politics, it is increasingly taking a legal form. A number of suits have been brought against OPEC, OPEC member states as well as their national oil companies or subsidiaries, often for alleged breach of national competition regulation. There have also been several attempts to use the WTO dispute settlement system to challenge OPEC member states that are also members of the WTO. This article attempts to answer the question of whether the petroleum production management practices of OPEC member states are subject to any external legal controls in the form of international economic law and the competition or antitrust laws of non-OPEC countries
Smoke and Mirrors:construction, trickery and surface in my work from a historical perspective
No full textAn article which assesses the role of materiality in Colvin's work, and particularly it’s significance in relation to the visual, literary and scientific themes explored within these works, seen in relation to the three-dimensional explorations of my recent ‘Natural Magic’ exhibition. The article was developed from an invited paper given at the SSHoP conference Photography in Scotland: 'then, now and beyond our time' at the Hawthornden Lecture Theatre, National Gallery, Edinburgh 27-28th March 2009.The article explores ideas of surface texture in the photographic image as a conceptual element, a theme which has become apparent through recent bodies of work in conjunction with technological developments in photography. A range of work is discussed in relation to methods of print production utilized for each project. Through this narrative Colvin discusses ideas inherent in the projects, and present an alternative reading of the works. This ‘exploration’ of surface image is presented predominantly through trompe l'oeil works, creating the impression of a surface that has a different three-dimensional structure to the painting. Initially Colvin turned the trompe l'oeil issue on its head - making the solid look flat. Colvin painted over three-dimensional structures and alignment was maintained because the final scene was photographed from the only point where this was possible. When viewing these photographs, the solid scene is initially overlooked and pictorial flatness dominates perception. With more protracted viewing, the objects in the scene emerge and a strange tension is introduced between the solid and the flat, between the scene and the seen. Objects in three dimensions are intentionally merged in the picture plane - and their identity is perceived after the flatness is transcended. The works in the ‘Natural Magic’ series represent a further development, and their conceptual and visual significance is discussed here
Transitions to Higher Education:a case study of students in Initial Teacher Education (ITE)
No full textThe aim of this case study is to explore issues relating to Transition into Higher Education for Undergraduate students. The support available to students during this time in their education will also be considered.The study reports on the process of transition for a year group of BEd (Hons) Primary Students. The transitional period in question will take into account the time before the students arrive at the University (applicant status), the time set aside for the induction of students and the time following this allotted transition period, the first four weeks of the semester. Throughout this time, the University as a whole and more specifically, the BEd Programme provide supportive mechanisms for the students. These resources include visit days, an online introduction to the course through the use of the Virtual Learning Environment and an induction programme tailored to the needs of the students.The discussion will take into account the changes for the students during this transitional period. This will focus mainly on the changes to the academic expectations and support of the students.Results have indicated that although the transition has worked well, the students have felt disadvantages in respect of support in academic preparedness and peer/social connections and support. The lack of support through ICT has also been apparent and this appears to be as a consequence of lack of engagement. The impact and implications for use of effective transitional models in Higher Education (HE) will be discussed and explored<br/
In vitro study of a multi-layer piezoelectric crystal attic hearing implant
No full textWe have developed a prototype middle-ear hearing implant which uses a multilayer piezoelectric actuator. Tn this series of experiments the actuator was attached to the medial wall of the attic so that it makes contact with the body of the incus. Initial in vitro evaluation has been carried out using a laser vibrometer (Polytec CLV) to measure stapes velocity. Stapes displacement is calculated by mathematical integration. The device used in this way is particularly effective at transmitting high frequency sound to the stapes. When switched off the actuator impairs the transmission of sound to the ossicular chain at low frequencies, but this effect is only 7 dB at most. The stapes displacements resulting from the action of the implant have a linear relationship with the voltages used to drive the system. The high capacitance of the present actuator means that its power requirements are higher than that of other comparable devices. An optimal method of coupling the device to the incus has yet to be identified.</p
An ultra-compact micro-valve for low pressure gas flow control
No full textWe describe the fabrication and performance characterisation of a ~0.1cm3 micro-valve, designed to regulate a compressed gas supply at pressures <1bar. The electro-active components were fabricated by ultra-precision grinding in combination with standard micro-fabrication techniques. The structural components were made from a photo-etchable glass-ceramic. Steady jets with velocities greater than 200m/s were measured using supply pressures = 60kPa and static actuation voltages = 40V. The gauge jet pressure ratio was linearly related to the static actuation voltage below 60kPa. The exceptional light weight of the valves and their simple construction could open up new possibilities for active aerodynamic flow-control systems, for medical diagnostics and for personalised healthcare systems, amongst other applications
Particle manipulation in a microfluidic channel with an electronically controlled linear piezoelectric array
Full text linkUltrasonic standing wave manipulation has been proved to be a simple, robust technology to be integrated in microfluidic systems for a range of applications such as particle filtration and concentration, particle trapping and washing, and sensor enhancement. Here we report recent progress in the design, fabrication and experimental demonstration of an electronically controlled ultrasonic array device used for 1-D manipulation of particles along a microfluidic channel. In a previous paper [1], the particle manipulation feasibility has been demonstrated by a 12 element, 500 µm pitch array device. In this paper, an improved 30-element, 200 µm pitch array device made from PZ26 piezoelectric composite has been fabricated and connected to control electronics. The control system comprises a Xilinx Spartan 3a FPGA development board and bespoke analogue driving circuitry, designed for signal multiplexing for array element excitation. A rectangular capillary forming a half wavelength resonance microfluidic chamber was coupled to the array to make a multilayer planar resonator. Manipulation under electronic control was demonstrated with 10 µm fluorescent microspheres suspended in water
The Gasotransmitter Hydrogen Sulfide Induces Nrf2-Target Genes by Inactivating the Keap1 Ubiquitin Ligase Substrate Adaptor Through Formation of a Disulfide Bond Between Cys-226 and Cys-613.
No full textAbstract Aims: The signaling molecule hydrogen sulfide (H2S) protects cells against oxidative stress and activates NF-E2 p45-related factor 2 (Nrf2), a transcription factor that regulates antioxidant genes. We sought to establish whether H2S requires Nrf2 to protect against oxidative stress, and whether activation of Nrf2 by H2S involves antagonism of Kelch-like ECH-associated protein-1 (Keap1), a redox-sensitive ubiquitin ligase substrate adaptor that represses Nrf2 under normal homeostatic conditions. Results: H2S stabilizes Nrf2 protein and induces Nrf2-target genes via an antioxidant-/electrophile-response element. In mouse embryonic fibroblasts, the ability of H2S to protect against cell death caused by the redox-cycling agent menadione is dependent on Nrf2. Moreover, Nrf2 regulates murine genes involved in the production of H2S (Cystathionine-beta-synthase [Cbs] and Cystathionine-gamma-lyase [Cse]) and the degradation of H2S (Sulfide:quinone reductase-like [yeast] [Sqrdl]). We found that H2S stabilizes Nrf2 through inhibition of Keap1, an event that requires covalent modification of amino acids C226 and C613 in the substrate adaptor. Upregulation of Nrf2 by H2S partially involves the production of H2O2, which inhibits Keap1 by stimulating the formation of an intramolecular disulfide bond between C226 and C613. The Keap1 C226 and C613 residues are also S-sulfhydrated by H2S, and this may entail reduction of the C226-C613 disulfide bridge formed by H2O2. Innovation: Upregulation of Nrf2 by H2S and H2O2 involves inactivation of Keap1 through modification of C226 and C613. Conclusion: Inhibition of Keap1 by H2S leads to Nrf2-mediated induction of cytoprotective genes. Nrf2 controls Cbs, Cse, and Sqrdl, suggesting that a feedback loop exists between Nrf2 and H2S. Antioxid. Redox Signal. 00, 000-000
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