UCL University College London Eprints
UCL Eprints collects the work of UCL researchers and makes it freely available over the web, helping the worldwide scholarly community to discover UCL research. Institutional repositories like UCL Eprints complement the traditional academic publishing and scholarly communications processes. They raise the visibility of research and help to maximise its impact. UCL researchers are encouraged to deposit a copy of each journal article, conference paper, working paper, and any other research output, in the UCL Eprints at the earliest opportunity, ensuring that their research reaches as wide an audience as possible.
Prevalence of Haemoproteus sp. in Galapagos blue-footed boobies: effects on health and reproduction - Cunningham, AA; Lee-Cruz, L; Martinez, P; Cruz, M; Goodman, SJ; Hamer, KC
Populations of blue-footed boobies in the Galápagos Islands have declined by at least 50% compared to numbers recorded during the 1960s. Recently, concern has been expressed about potential adverse effects of introduced blood parasites; in particular, malarial parasites (i.e. Plasmodium sp.), which are frequently pathogenic and can cause mortality and morbidity in birds, and blood parasites of the genus Haemoproteus, which can reduce fitness. We screened blue-footed boobies at six breeding colonies within Galápagos for both genera of parasite. At two sites, we also investigated whether there was any relationship between infection status and physiological condition or breeding success. We...
Gradient-based quantitative image reconstruction in ultrasound-modulated optical tomography: first harmonic measurement type in a linearised diffusion formulation - Powell, S; Arridge, SR; Leung, TS
Ultrasound-modulated optical tomography is an emerging biomedical imaging modality which uses the spatially localised acoustically-driven modulation of coherent light as a probe of the structure and optical properties of biological tissues. In this work we begin by providing an overview of forward modelling methods, before deriving a linearised diffusion-style model which calculates the first-harmonic modulated flux measured on the boundary of a given domain. We derive and examine the correlation measurement density functions of the model which describe the sensitivity of the modality to perturbations in the optical parameters of interest. Finally, we employ said functions in the development of...
The Association between Contact and Intellectual Disability Literacy, Causal Attributions and Stigma - Blundell, R; Scior, K
Background: Contact is seen as a key route to tackling stigma and discrimination. Contact theory states that the quality and type of contact, as well as circumstance of the contact experience, influence the effect of contact on prejudice. The majority of research in intellectual disabilities though has focused on contact as present or absent only. Method: 1264 adult members of the UK general population completed measures of symptom recognition, social distance (as measure of external stigma) and causal beliefs in response to a diagnostically unlabelled vignette, depicting someone with intellectual disabilities. Results: A nuanced contact variable, including frequency of contact...
Absolute Differential Positronium-Formation Cross Sections. - Shipman, M; Armitage, S; Beale, J; Brawley, SJ; Fayer, SE; Garner, AJ; Leslie, DE; Van Reeth, P; Laricchia, G
The first absolute experimental determinations of the differential cross sections for the formation of ground-state positronium are presented for He, Ar, H2, and CO2 near 0°. Results are compared with available theories. The ratio of the differential and integrated cross sections for the targets exposes the higher propensity for forward emission of positronium formed from He and H2.
Simulated field maps for susceptibility artefact correction in interventional MRI - Kochan, M; Daga, P; Burgos, N; White, M; Cardoso, MJ; Mancini, L; Winston, GP; McEvoy, AW; Thornton, J; Yousry, T; Duncan, JS; Stoyanov, D; Ourselin, S
PURPOSE: Intraoperative MRI (iMRI) is a powerful modality for acquiring images of the brain to facilitate precise image-guided neurosurgery. Diffusion-weighted MRI (DW-MRI) provides critical information about location, orientation and structure of nerve fibre tracts, but suffers from the "susceptibility artefact" stemming from magnetic field perturbations due to the step change in magnetic susceptibility at air-tissue boundaries in the head. An existing approach to correcting the artefact is to acquire a field map by means of an additional MRI scan. However, to recover true field maps from the acquired field maps near air-tissue boundaries is challenging, and acquired field maps are...
Technical study of a rare Venetian turquoise glass goblet from the Waddesdon Bequest - Thornton, D; Freestone, I; Meek, A; Gudenrath, W; Ling, D; Bertini, M
A Venetian enamelled and gilded goblet (WB.55) is part of the collection bequeathed to the British Museum by Baron Ferdinand Rothschild in 1898. Conservation treatment in 1994 provided the opportunity to remove a small sample containing some opaque white as well as rare turquoise glass. These fragments were analysed using scanning electron microscopy with energy dispersive X-ray spectrometry and by laser ablation inductively coupled plasma mass spectrometry. Further analyses were carried out on the enamels and blue glass knop of the goblet using surface X-ray fluorescence. This contribution locates the object in the context of Venetian glass of the Renaissance...
Hippocampal circuit dysfunction in the Tc1 mouse model of Down syndrome. - Witton, J; Padmashri, R; Zinyuk, LE; Popov, VI; Kraev, I; Line, SJ; Jensen, TP; Tedoldi, A; Cummings, DM; Tybulewicz, VL; Fisher, EM; Bannerman, DM; Randall, AD; Brown, JT; Edwards, FA; Rusakov, DA; Stewart, MG; Jones, MW
Hippocampal pathology is likely to contribute to cognitive disability in Down syndrome, yet the neural network basis of this pathology and its contributions to different facets of cognitive impairment remain unclear. Here we report dysfunctional connectivity between dentate gyrus and CA3 networks in the transchromosomic Tc1 mouse model of Down syndrome, demonstrating that ultrastructural abnormalities and impaired short-term plasticity at dentate gyrus-CA3 excitatory synapses culminate in impaired coding of new spatial information in CA3 and CA1 and disrupted behavior in vivo. These results highlight the vulnerability of dentate gyrus-CA3 networks to aberrant human chromosome 21 gene expression and delineate hippocampal...
Continuous Heterogeneously Catalyzed Oxidation of Benzyl Alcohol Using a Tube-in-Tube Membrane Microreactor - Wu, G; Constantinou, A; Cao, E; Kuhn, S; Morad, M; Sankar, M; Bethell, D; Hutchings, GJ; Gavriilidis, A
A Teflon AF-2400 tube-in-tube microreactor is investigated for the continuous, solvent-free, catalytic oxidation of benzyl alcohol with oxygen. The semipermeable Teflon AF-2400 tube acts as the interface between the gaseous oxidant and the liquid substrate. Because of the inherent safety of this contacting method, the use of pure oxygen is possible. The semipermeable tube was packed with 1 wt % Au–Pd/TiO2 catalyst particles and placed inside a PTFE tube to provide an annular region which was pressurized with pure oxygen. This design allowed continuous penetration of oxygen through the inner tube during the reaction, resulting in higher oxygen concentration in...
An evaluation of the implementation and impact of England's mandated school-based mental health initiative - Wolpert, M; Humphrey, N; Deighton, J; Patalay, P; Fugard, AJB; Fonagy, P; Belsky, J; Vostanis, P
We report on a large, randomized controlled trial of a nationally-mandated, school-based mental health program in England: Targeted Mental Health in Schools (TaMHS). TaMHS aimed to improve mental health for students with, or at risk of, behavioral and emotional difficulties, by provision of evidence-informed interventions relating to closer working between health and education services. Our study involved 8,480 children (aged 8-9 years) from 266 elementary schools. Students in intervention schools with, or at risk of, behavioral difficulties reported significant reductions in behavioral difficulties compared to control school students, but no such difference was found for students with, or at risk...
The loss of the healthy child: Exploring the relationship between mothers' early attachment relationships and their reaction to their child's learning disability. - Fletcher, H.
The distress experienced by parents, on learning that their child has a diagnosis of a learning disability, has been well documented. Goldberg, Magrill, Hale et al. (1995) proposed that parents go through a process of grieving the loss of the healthy or perfect child to whom they expected to give birth. Some parents appear able to resolve loss and trauma surrounding their child's condition fairly quickly, whilst others continue to experience difficulty for many years. This study explored the relationship between mothers' states of mind with respect to early attachment relationships and their reaction to discovering their child has a...
Functional neuroimaging studies of long term memory in humans. - Fletcher, P.C.
This thesis explores contributions of prefrontal cortex (PFC) to memory using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). I begin by considering the cognitive neuroscience of memory processes and the impact that functional neuroimaging may have upon this. I then describe a series of PET and fMRI experiments concerned, primarily, with dissociating frontal contributions to encoding and retrieval processes. These initial studies show that left PFC activation predominates at encoding and right PFC activation at retrieval. Four further studies of left prefrontal activation at encoding are presented. Together, they show that left PFC is sensitive to tasks...
The role of ephrinB2 in blood vessel development. - Foo, S.S.C.
The development of the vascular network is a complex process that is controlled by precisely balanced angiogenic and anti-angiogenic factors. Several studies have established that ephrinB2 and its receptor EphB4 are important regulators of angiogenic remodelling in the embryonic vasculature. The ablation of either gene in mice leads to fatal cardiovascular defects and early lethality. As ephrinB2 is expressed in different cell types within blood vessels, specifically in arterial endothelial cells, pericytes and vascular smooth muscle cells, the function of the molecule in each cell population has remained unclear. To determine the role of ephrinB2 expression in the luminal endothelial...
Inferential knowledge, externalism and self-knowledge. - Ford, R.G.
Privileged self-knowledge says, roughly, that we have non-empirical knowledge of our own thoughts. Externalism about mental content says, roughly, that our mental states are determined at least in part by our environment. It has been alleged that jointly assuming externalism about mental content and privileged self-knowledge are true has the consequence that any subject can have non-empirical knowledge of her own environment and this is intuitively absurd. The thesis investigates in various ways the problem arises and focuses on the following principle: Knowledge Transmission Principle: For any subject S and any proposition P and any proposition Q: if S has...
Role of cyclophilins and heat shock proteins in myocardial ischaemia/reperfusion injury. - Folarin, N'deen
Restoration of blood flow after myocardial infarction (MI), surgery or fibrinolytic therapy is necessary, but can lead to cardiomyocyte dysfunction within a generalised condition commonly known as "reperfusion injury". The role of cyclophilins, heat shock proteins (HSP), and the mitochondrial chaperone complex (MCC), was studied in this pathological condition. In vitro and in vivo models were used to replicate conditions of ischaemia/reperfusion (IR) injury. H9c2 and COS-7 cell lines were employed in nitric oxide (NO) donor and transfection applications. Experimental protocols were used to determine mitochondrial membrane potential (MMP), mitochondrial morphology, protein expression, enzyme activity and cell damage in these...
Essays on education and work choices in developing and developed economies. - Fitzsimons, E.O.A.
This thesis focuses on education and work choices of individuals in both developing and developed economies. Such economic settings are distinguishable partly in terms of the features and constraints underlying individual decision-making, which impact on the disparity in education levels between low- and high-income economies. In particular, low-income settings are characterised by a large degree of poverty, risk and uncertainty in daily life, the effects of which are often exacerbated by a lack of risk diversification mechanisms due to thin insurance markets and high borrowing constraints. These features have important implications for investment in education. The higher levels of investment...
Mathematical models of the impact of rabbit calicivirus disease (RCD) on the European rabbit, Oryctolagus cuniculus, in Australia. - Fiorentino, F.
This thesis relates to the work of building a mathematical model of the impact of Rabbit Calicivirus Disease (RCD) on the European Rabbit, Oryctolagus cuniculus, in Australia. After introducing the general biology of rabbits and the immunology of RCD, we build a time-dependent single site model. We construct a single-site population dynamic model with age structure, seasonal birth rate, density dependent regulation of the population size and climatic variability for various regions of Australia. After investigating suitable parameter ranges, we incorporate the disease dynamics through an indirect transmission model based on two different hypotheses which we call the Strong Juvenile...
Variation within households in consent to link survey data to administrative records: evidence from the UK Millennium Cohort Study - Mostafa, T
This study expands our knowledge of consent in linking survey and administrative data by studying respondents’ behaviour when consenting to link their own records and when consenting to link those of their children. It develops and tests a number of hypothesised mechanisms of consent, some of which were not explored in the past. The hypotheses cover: parental pride, privacy concerns, loyalty to the survey, pre-existing relations with the agency holding the data, and interviewer effects. The study uses data from the longitudinal Millennium Cohort Study to analyse the correlates of consent in multiple domains (i.e. linkage of education, health and...