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University of Leeds

Country: United Kingdom

University of Leeds

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4,274 Projects, page 1 of 855
  • Funder: UKRI Project Code: NE/D008263/1
    Funder Contribution: 43,104 GBP

    This project is concerned with dating the metamorphic history of once deeply-buried crust and relating these dates directly to the deformation structures that formed while these rocks returned towards the Earth's surface. These materials (so-called high pressure (HP) metamorphic rocks / eclogites and blueschists) and their equivalents (greenschists, recrystallised under lower pressure conditions) are important recorders of the vertical movements in plate boundary zones and thus underpin many tests of geodynamic models. Important questions include: Are HP conditions experienced at distinct times to lower P (greenschist) conditions? Do different parts of an HP terrain exhume at different times, creating an amalgam of HP fragments? What are the rates of exhumation? Answers to these questions impact directly on a vigorous debate concerning subduction zone processes. Do these zones experience distinct periods of local tectonic divergence within otherwise convergent plate boundary zones with lithosphere-wide necking and exhumation of HP rocks punctuated by periods of renewed burial? Or, is material continuously cycled down and up subduction zones as detached 'pips'. To address the questions it is necessary to date the mineral fabrics that link to deformation and metamorphic conditions. We will use the rubidium-strontium method to date phengite mica growth and recystallisation, a method proven by us in deformation age dating of rocks sheared under greenschist facies conditions in the Alps. It is now timely to extend the approach to track rocks explicitly through decompression / from blueschist into greenschist facies. We will focus on the spectacular blueschists of the Attic-Cyclades belt exposed on the island of Syros. These are highly suitable not only because the tectono-metamorphic history is much more tractable on the outcrop scale than in the Alps but also because peak temperatures did not exceed 500C, the closure temperature for the Rb-Sr system in phengite. Existing models imply punctuated exhumation of the Syros blueschists rocks to greenschist facies conditions (from 20 kbar, ~70km depth to c. 6 kbar, ~20km). However, the models rely on isotopic ages for peak pressure metamorphic minerals (e.g. U-Pb ages on the mineral zircon) and cooling ages (Ar ages on micas, apparently dating the last experience of ~350C for the rocks). Neither approach can readily be related to specific deformation fabrics. The Rb-Sr method can. Consequently our research will establish, for the first time, the rates of decompression and related deformation over a wide range of exhumation conditions charted by single outcrops. Advances in micro-sampling and mass spectrometry now allow the detailed work necessary to date fabrics within specimens that show repeated mineral growth and structural overprint. We will build on the regional expertise and sample collections held in Edinburgh to focus on well-characterised structures. These researches show the Syros blueschists to be ideal for our purpose: the mica chemistries and relationships to metamorphic assemblages are very well characterised showing a wide range of pressure conditions with phengite growth and recrystallisation during deformation and decompression. The chemical composition of phengite is sensitive to the pressure conditions during mineral growth. And phengite commonly defines the deformation fabric in the rocks. By contrasting the dated decompression history of the HP rocks on Syros we will establish whether their exhumation was a pulsed, punctuated process or was continuous, and whether different parts of the HP terrain exhumed at different times and different rates. Not only will these results help to understand the geological evolution of the HP rocks on Syros, they will provide direct tests of the competing models for the exhumation of HP rocks, and provide fundamental data on the rates and dynamics of subduction zone processes.

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  • Funder: UKRI Project Code: 2745608

    This project will look at some aspect of medical diagnosis through the application of Artificial Intelligence which will be determined in more detail by the end of year one

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  • Funder: UKRI Project Code: BB/W017644/1
    Funder Contribution: 501,634 GBP

    Hepatitis B Virus is the major cause of liver cancer worldwide. Despite the availability of an effective, safe and cheap vaccine roughly a million people are newly infected each year. They join a cohort of about 240 million patients who suffer from chronic HBV infection after failing to fully clear an initial exposure to the virus. The current outlook for these people is poor since the major clinical anti-viral drugs, directed at the reverse transcriptase active site of the viral polymerase, do not eradicate virus, and therefore imply lifelong treatment. Sadly, death from HBV induced liver cancer is lowered only by a maximum of 4-fold after decades of this treatment. Over 700,000 people die roughly every year as a result of infection which causes liver failure, cirrhosis and liver cancer. The WHO have issued a Global Challenge to make HBV infection a treatable disease by 2030. A major barrier to meeting this challenge is the difficulty in studying the viral polymerase in its native environment - a virally-induced protein container composed of virally-encoded core protein, in which the viral nucleic acid is converted from a single-stranded RNA form to a nicked double-stranded DNA version, the source of continued infection in the liver. This difficulty is principally due to the polymerase, which is only poorly soluble in most conditions. We have developed a unique system that can be studied safely in the bacterium E.coli, in which the polymerase is stabilised by binding to its native RNA target, the epsilon stem-loop, within a native-like viral protein shell. We will use this system to investigate how the enzyme achieves these potentially lethal nucleic acid transformations within this specialised protein container using spectroscopic techniques to assay the enzymatic reactions. These will be coupled with state-of-the-art structural studies in our world-class electron microscopy laboratory, and a specialised technique we have developed for studying the structures of nucleic acids within viruses. These will allow us to explore the mechanisms of action of leading novel anti-viral drug candidates, and make this system widely available for rapid therapeutic exploitation.

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  • Funder: EC Project Code: 743642
    Overall Budget: 183,455 EURFunder Contribution: 183,455 EUR

    This goal of this project is to obtain a deeper, molecular level understanding of chemical reactions important to atmospheric and planetary chemistry, specifically reactions involved in the oxidation of organic sulfur molecules. A common theme to experimentally determining chemical reaction rates is to monitor the disappearance of a reactant, perhaps even under pseudo-first order conditions. An ideal experiment, however, would monitor the loss of each reactant and the appearance of each product, under known temperature and pressure conditions, in order to gain a more complete picture of the reaction. This project is a significant step towards the ideal kinetic experiment. Here, mid-infrared cavity-enhanced direct frequency comb spectroscopy (CE-DFCS), a technology used almost exclusively in the physics community, will be used as a tool in the chemistry community to spectroscopically identify reactants, transient species, and products based on their vibrational absorption spectra. This is a rapid, sensitive, broadband, and high-resolution technique, which enables reaction rates to be derived based on the simultaneous measurement of both the reactant disappearance and product appearance. Moreover, CE-DFCS will be coupled to a pulsed Laval supersonic expansion, an essentially wall-less reactor with well-characterized pressure and temperature conditions. Temperature dependent rate constants will be measured over a wide temperature range, relevant to Earth’s atmosphere or even parts of the interstellar medium. This project has a strong interdisciplinary component, combining optical physics, fundamental physical chemistry, and atmospheric chemistry. This attribute arises from the significant two-way transfer of knowledge between the researcher and the Atmospheric and Planetary Chemistry group at the University of Leeds. In addition, the fellow will receive training during the tenure of the fellowship to enable her to become a successful independent scientist.

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  • Funder: UKRI Project Code: 2443517

    This project is concerned with the grey area between extremism and terrorism in the United Kingdom's (UK) Prevent Strategy (HM Government, 2011). It is the result of, inter alia, a conceptual quagmire which has tended to obscure the boundaries between "acceptable" non-violent extremism and "unacceptable" not (yet) violent extremism (Lowe, 2017), with the latter justifiably requiring Prevent involvement for it being a conduit to terrorism. Yet, while academic debate has highlighted a large grey area between the two, chiefly focussing on the need for clearer distinctions between them, there has been a lack of focus on how Prevent practitioners in the local authority and police deal with the dilemma of identifying those who subscribe to the notion of not (yet) violent extremism (Schmid, 2014). This proposed study will fill this gap, narrowing the focus down to empirically explore how Prevent officers in these respective organisations judge an expression as passing the violent threshold needed to reconcile an expression with terrorism and constitute counter-terrorism involvement. This focus will be enabled through the application of the following research questions: 1. How do counter-terrorism practitioners respond to incidents occupying a grey area between extremism and terrorism? 2. In responding to those who may be on the cusp of terrorist engagement, what can be deemed as being 'good practice'? 3. What are the implications of responding to non-violent extremism through counter-terrorism instruments?

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