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UCL University College London Eprints (356,300 recursos)
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.

Mostrando recursos 181 - 200 de 355,838

181. Calculating the curvature shape characteristics of the human body from 3D scanner data. - Douros, I.
In the recent years, there have been significant advances in the development and manufacturing of 3D scanners capable of capturing detailed (external) images of whole human bodies. Such hardware offers the opportunity to collect information that could be used to describe, interpret and analyse the shape of the human body for a variety of applications where shape information plays a vital role (e.g. apparel sizing and customisation; medical research in fields such as nutrition, obesity/anorexia and perceptive psychology; ergonomics for vehicle and furniture design). However, the representations delivered by such hardware typically consist of unstructured or partially structured point clouds,...

182. Rasch analysis and item reduction of the Chinese version of the 20-item Toronto Alexithymia Scale (TAS-20-C) for adolescents - Tam, KHB; Wong, WS
Introduction: The TAS-20 is a psychometrically validated instrument for assessing alexithymia in adult populations. However, the instrument is not well-established in adolescents. Objective and aims: The objective of this study was to validate the Chinese version of the TAS-20 (TAS-20-C). Two studies aimed to produce a short form of the TAS-20-C and evaluate its subsequent factor structure in a sample of Chinese adolescents across different grade levels using confirmatory factor analysis (CFA). Methods: The Mandarin version of the TAS-20-C was modified with respect to the local colloquial and was tested in two separate samples of Chinese adolescents. In Study 1...

183. Sharing a Context with Other Rewarding Events Increases the Probability that Neutral Events will be Recollected. - Loh, E; Deacon, M; de Boer, L; Dolan, RJ; Duzel, E
Although reward is known to enhance memory for reward-predicting events, the extent to which such memory effects spread to associated (neutral) events is unclear. Using a between-subject design, we examined how sharing a background context with rewarding events influenced memory for motivationally neutral events (tested after a 5 days delay). We found that sharing a visually rich context with rewarding objects during encoding increased the probability that neutral objects would be successfully recollected during memory test, as opposed to merely being recognized without any recall of associative detail. In contrast, such an effect was not seen when the context was...

184. Context-specific activation of hippocampus and SN/VTA by reward is related to enhanced long-term memory for embedded objects - Loh, E; Kumaran, D; Koster, R; Berron, D; Dolan, R; Duzel, E
Animal studies indicate that hippocampal representations of environmental context modulate reward-related processing in the substantia nigra and ventral tegmental area (SN/VTA), a major origin of dopamine in the brain. Using functional magnetic resonance imaging (fMRI) in humans, we investigated the neural specificity of context-reward associations under conditions where the presence of perceptually similar neutral contexts imposed high demands on a putative hippocampal function, pattern separation. The design also allowed us to investigate how contextual reward enhances long-term memory for embedded neutral objects. SN/VTA activity underpinned specific context-reward associations in the face of perceptual similarity. A reward-related enhancement of long-term memory...

185. The use of internet-mediated cross-sectional studies in mental health research - Pitman, A; Osborn, DPJ; King, MB
This article summarises internet-mediated approaches to conducting quantitative and qualitative cross-sectional mental health research, and describes aspects of research design to consider for optimising scientific rigour and validity as well as response. Rapid adoption of internet-mediated approaches risks compromising the quality of the methods used. Not only can it cause distress to participants, but methodological problems may lead to inappropriate inferences being made from research findings. In this article the advantages of using internet communication for research purposes are balanced against the disadvantages, using examples of recent internet-mediated research (IMR) studies to illustrate good practice. LEARNING OBJECTIVES: • Appreciate the...

186. 10-y Risks of Death and Emergency Re-admission in Adolescents Hospitalised with Violent, Drug- or Alcohol-Related, or Self-Inflicted Injury: A Population-Based Cohort Study. - Herbert, A; Gilbert, R; González-Izquierdo, A; Pitman, A; Li, L
BACKGROUND: Hospitalisation for adversity-related injury (violent, drug/alcohol-related, or self-inflicted injury) has been described as a "teachable moment", when intervention may reduce risks of further harm. Which adolescents are likely to benefit most from intervention strongly depends on their long-term risks of harm. We compared 10-y risks of mortality and re-admission after adversity-related injury with risks after accident-related injury. METHODS AND FINDINGS: We analysed National Health Service admissions data for England (1 April 1997-31 March 2012) for 10-19 y olds with emergency admissions for adversity-related injury (violent, drug/alcohol-related, or self-inflicted injury; n = 333,009) or for accident-related injury (n = 649,818)....

187. The social cognition of medical knowledge: with special reference to childhood epilepsy - MacDonald, MN; Badger, R; O'Regan, J
This article arose out of an engagement in medical communication courses at a Gulf university. It deploys a theoretical framework derived from a (critical) sociocognitive approach to discourse analysis in order to investigate three aspects of medical discourse relating to childhood epilepsy: the cognitive processes that are entailed in relating different types of medical knowledge to their communicative context; the types of medical knowledge that are constituted in the three different text types analyzed; and the relationship between these different types of medical knowledge and the discursive features of each text type. The article argues that there is a cognitive...

188. The text as a critical object: on theorising exegetic procedure in classroom-based critical discourse analysis - O'Regan, JP
One of the reasons why critical discourse analysis (CDA) calls itself critical is because its perspectives of discourse and society are derived largely from critical social theory. Transferring these perspectives to educational contexts requires that teachers develop workable pedagogic frameworks and procedures which apply CDA principles and practices to the reading and discussion of texts in the classroom. If these are to be considered ‘critical’, it seems useful that these are also derived from critical social theory. This type of critical theorisation seems to be underdeveloped in a CDA which relies principally on systemic functional linguistics for its procedural attitude...

189. Subaltern geographies: Geographical knowledge and postcolonial strategy - Jazeel, T
In recent years a small but rich geographical literature has engaged with Subaltern Studies to explore the geographical and geopolitical imaginations of subaltern subjects and groups. Such writings have deployed subalternity to designate a substantive subject or group marginalized in the face of power. Departing from this, the paper instead treats subalternity more figuratively, as a word able to evoke spatialities occluded by the Euro-American power that haunts disciplinary geography. The paper argues that using subalternity like this holds the potential to pluralize geographical interventions, particularly in the light of the discipline's materialist turns since the late 1990s. To make...

190. Micro-anatomical and functional assessment of ciliated epithelium in mouse trachea using optical coherence phase microscopy - Ansari, R; Buj, C; Pieper, M; König, P; Schweikard, A; Hüttmann, G
Motile cilia perform a range of important mechanosensory and chemosensory functions, along with expulsion of mucus and inhaled pathogens from the lungs. Here we demonstrate that spectral domain optical coherence phase microscopy (SD-OCPM), which combines the principles of optical coherence tomography (OCT) and confocal microscopy, is particularly well-suited for characterization of both morphology and the ciliary dynamics of mouse trachea. We present micro-anatomical images of mouse trachea, where different cell types can be clearly visualized. The phase contrast, which measures the sub-nanometer changes in axial optical pathlength is used to determine the frequency and direction of cilia beatings.

191. Ultrahigh-resolution, high-speed spectral domain optical coherence phase microscopy - Ansari, R; Myrtus, C; Aherrahrou, R; Erdmann, J; Schweikard, A; Hüttmann, G
We present an ultrahigh-resolution, high-speed spectral domain optical coherence phase microscopy (SD-OCPM) system that combines submicrometer transverse spatial resolution and subnanometer optical path length sensitivity, with an acquisition speed of over 217,000  voxels/s. The proposed SD-OCPM system overcomes two significant drawbacks of traditional common-path interferometers—limited transverse spatial resolution and suboptimal detection sensitivity—while maintaining phase stability that is comparable with common-path interferometer setups. The transverse and axial spatial resolution of the setup is measured to be 0.6 and 1.9 μm, respectively, with a phase sensitivity of 0.0027 rad (corresponds to optical path length sensitivity of 110 pm). High-speed acquisition allows for phase-sensitive...

192. Dating Iron Age goldwork: First direct AMS 14C results from Northwestern Iberia - Armada, XL; García-Vuelta, O
This article presents the first direct radiocarbon dates for NW Iberian “Castro culture” goldwork. Three samples were taken from a melting mass and a plano-convex ingot from the so-called Recouso (Oroso, A Coruña) and Calvos de Randín (Ourense) “hoards”. The study includes pXRF analysis of the pieces from both assemblages. Identifi- cation of charcoal samples allowed us to better evaluate the results. The dates point to a period late in the Second Iron Age for both assemblages. They are the first direct chronological references for this rich goldworking tradition after more than a hundred years of investigation and they open up a line of research that offers...

193. Which dogs with appendicular osteosarcoma benefit most from chemotherapy after surgery? Results from an individual patient data meta-analysis - Schmidt, AF; Groenwold, RHH; Amsellem, P; Bacon, N; Klungel, OH; Hoes, AW; de Boer, A; Kow, K; Maritato, K; Kirpensteijn, J; Nielen, M
© 2015 Elsevier B.V. Osteosarcoma (OS) is a malignant tumor of mesenchymal origin that produces osteoid. Given that the prognosis can vary considerably between dogs, we aimed to explore whether treatment could be tailored towards patient subgroups, characterized by their predicted risk of mortality. For the current study, a subset of five nonrandomized studies (400 subjects of whom 88 were dead at 5 months follow-up) was used from a previously published 20 study individual patient data meta-analysis. Missing data was dependent on observed variables and was imputed to correct for this dependency. Based on a previously published multivariable prognostic model,...

194. Moving to metrics: Opportunities and challenges of performance-based sustainability standards - Veale, M; Seixas, R
The rise of global sustainability standards has led to an energetic discussion about their consequences and outcomes. Almost all standards today are built around ‘technology-based’ indicators, which prescribe certain practices assumed to lead to sustainable outcomes. However we are now seeing the emergence of the first ‘performance-based’ metric sustainability indicators, directly measuring outcomes without prescribing particular methods to reach them. This paper presents the example of the Bonsucro Production Standard, a sustainability standard for the sugarcane sector, and identifies five relevant areas opened up by performance-based metrics. These are flexibility in application, provision of information, the creation of dynamic standards,...

195. Accuracy of van der Waals inclusive DFT functionals for ice at ambient and high pressures - Santra, B; Klimes, J; Tkatchenko, A; Alfe, D; Slater, B; Michaelides, A; Car, R; Scheffler, M
Density-functional theory (DFT) has been widely used to study water and ice for at least 20 years. However, the reliability of different DFT exchange-correlation (xc) functionals for water remains a matter of considerable debate. This is particularly true in light of the recent development of DFT based methods that account for van der Waals (vdW) dispersion forces. Here, we report a detailed study with several xc functionals (semi-local, hybrid, and vdW inclusive approaches) on ice Ih and six proton ordered phases of ice. At higher pressure, the contribution to the lattice energy from vdW increases and that from hydrogen bonding...

196. Origin of Oxygenic Photosynthesis from Anoxygenic Type I and Type II Reaction Centers - Allen, J
All anoxygenic photosynthetic bacteria currently known have photosynthetic reaction centres of only one type, either Type I or II. In contrast, all oxygenic photosynthetic systems – of plants, algae and cyanobacteria – have both Type I and Type II reaction centres. Molecular oxygen is the oxidation product of water in a Type II reaction centre that is connected, in series, with a Type I reaction centre. Around 2.4 billion years ago, the evolutionary origin of this series connection initiated biological water oxidation and began to transform our planet irrevocably. Here I consider the question of how separate Type I and...

197. Mitochondrial genome function and maternal inheritance - Allen, JF; de Paula, WBM
The persistence of mtDNA to encode a small subset of mitochondrial proteins reflects the selective advantage of co-location of key respiratory chain subunit genes with their gene products. The disadvantage of this co-location is exposure of mtDNA to mutagenic ROS (reactive oxygen species), which are by-products of aerobic respiration. The resulting ‘vicious circle’ of mitochondrial mutation has been proposed to underlie aging and its associated degenerative diseases. Recent evidence is consistent with the hypothesis that oocyte mitochondria escape the aging process by acting as quiescent genetic templates, transcriptionally and bioenergetically repressed. Transmission of unexpressed mtDNA in the female germline is...

198. Why chloroplasts and mitochondria retain their own genomes and genetic systems: Colocation for redox regulation of gene expression - Allen, JF
Chloroplasts and mitochondria are subcellular bioenergetic organelles with their own genomes and genetic systems. DNA replication and transmission to daughter organelles produces cytoplasmic inheritance of characters associated with primary events in photosynthesis and respiration. The prokaryotic ancestors of chloroplasts and mitochondria were endosymbionts whose genes became copied to the genomes of their cellular hosts. These copies gave rise to nuclear chromosomal genes that encode cytosolic proteins and precursor proteins that are synthesized in the cytosol for import into the organelle into which the endosymbiont evolved. What accounts for the retention of genes for the complete synthesis within chloroplasts and mitochondria...

199. A two-component regulatory system in transcriptional control of photosystem stoichiometry: redox-dependent and sodium ion-dependent phosphoryl transfer from cyanobacterial histidine kinase Hik2 to response regulators Rre1 and RppA - Allen, JF; Ibrahim, IM; Puthiyaveetil, S
We report on regulation and interactions of a unique histidine sensor kinase, Hik2. Hik2 is found in all known cyanobacteria, but has no previously identified functional response regulator. Here we show that it transfers phosphate rapidly, in vitro, to two response regulators, termed Rre1 and RppA. Hik2 is of special importance in being indispensable to cyanobacteria, and in being the closest cyanobacterial homologue of the uniquely conserved Chloroplast Sensor Kinase (CSK), which couples photosynthetic electron transport to gene transcription. Hik2 function is so important that it has survived the transition from cyanobacterium to eukaryotic sub-cellular organelle. Hik2 is likely to...

200. Social networks and regional economic development: The Los Angeles and Bay Area metropolitan regions, 1980–2010 - Makarem, NP
Social capital is widely recognized as an important aspect of regional economies, and social networks in particular have recently been the focus of research in economic sociology and economic geography. Building on this body of work, this research explores the role of social networks in the divergent economic fortunes of two highly advance Californian metropolitan regions over the past three decades, Los Angeles and the Bay Area. Proxies for the two regions’ industrial social structures are constructed and analysed at three cross sections over the divergence period: 1982, 1995 and 2010. Network analysis shows that the Bay Area’s industrial social...

 

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