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UCL University College London Eprints (400.673 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 81 - 100 de 6.590

  1. Saving the gene pool for the future: Seed banks as archives

    Peres, S
    Ensuring the salvage of future sources is a challenge for plant geneticists and breeders, as well as historians and archivists. Here, this suggestion is illustrated with an account of the emergence, in the mid-20th century, of seed banks. These repositories are intended to enable the conservation of the world's crop genetic diversity against the ‘genetic erosion’ of crops, an unintended consequence of the global uptake of new high-yielding Green Revolution agricultural varieties. Plant breeders and scientists advocated a strategy of freezing and long-term storage of seed which enabled the salvage of genetic diversity for future users without requiring the continual...

  2. Mild hyponatremia, hypernatremia and incident cardiovascular disease and mortality in older men: A population-based cohort study

    Wannamethee, SG; Shaper, AG; Lennon, L; Papacosta, O; Whincup, P
    AIM: To examine the association between serum sodium concentration and incident major cardiovascular disease (CVD) outcomes and total mortality in older men. METHODS AND RESULTS: A prospective study of 3099 men aged 60-79 years without a history of cardiovascular disease followed up for an average 11 years during which there were 528 major CVD events (fatal coronary heart disease [CHD] and non-fatal MI, stroke and CVD death) and 873 total deaths. A U shaped relationship was seen between serum sodium concentration and major CVD events and mortality. Hyponatremia (<136 mEq/L) and low sodium within the normal range (136-138 mEq/L) showed significantly increased...

  3. Effectiveness of legislative changes obligating notification of prolonged sickness absence and assessment of remaining work ability on return to work and work participation: a natural experiment in Finland

    Halonen, JI; Solovieva, S; Pentti, J; Kivimäki, M; Vahtera, J; Viikari-Juntura, E
    OBJECTIVES: Policies have been introduced to reduce sickness absence, but their effectiveness is largely unknown. In a natural experiment, we examined effects of legislative changes on return to work and work participation. METHODS: The source population consisted of up to 72 164 Finnish public sector employees with a permanent job contract in 2008-2011 (before) and in 2013-2014 (after). We used employees with a continuous sickness absence of at least 30 calendar-days (n=5708-6393), 60 compensated days (n=1481-1655) and 90 compensated days (n=766-932). We examined sustainable return to work (a minimum of 28 consecutive working days) with survival analysis as well as monthly...

  4. Flexible integration of visual cues in adolescents with autism spectrum disorder

    Bedford, R; Pellicano, E; Mareschal, D; Nardini, M
    Although children with autism spectrum disorder (ASD) show atypical sensory processing, evidence for impaired integration of multisensory information has been mixed. In this study, we took a Bayesian model-based approach to assess within-modality integration of congruent and incongruent texture and disparity cues to judge slant in typical and autistic adolescents. Human adults optimally combine multiple sources of sensory information to reduce perceptual variance but in typical development this ability to integrate cues does not develop until late childhood. While adults cannot help but integrate cues, even when they are incongruent, young children's ability to keep cues separate gives them an...

  5. Hepatitis C virus seroprevalence in pregnant women delivering live-born infants in North Thames, England in 2012

    Cortina-Borja, M; Williams, D; Peckham, CS; Bailey, H; Thorne, C
    To estimate HCV seroprevalence in subpopulations of women delivering live-born infants in the North Thames region in England in 2012, an unlinked anonymous (UA) cross-sectional survey of neonatal dried blood spot samples was conducted. Data were available from 31467 samples from live-born infants received by the North Thames screening laboratory. Thirty neonatal samples had HCV antibodies, corresponding to a maternal seroprevalence of 0·095% (95% confidence interval 0·067-0·136). Estimated HCV seroprevalences in women born in Eastern Europe, Southern Asia and the UK were 0·366%, 0·162% and 0·019%, respectively. For women born in Eastern Europe seroprevalence was highest in those aged around...

  6. Pre-referral general practitioner consultations and subsequent experience of cancer care: evidence from the English Cancer Patient Experience Survey

    Mendonca, SC; Abel, GA; Saunders, CL; Wardle, J; Lyratzopoulos, G
    Prolonged diagnostic intervals may negatively affect the patient experience of subsequent cancer care, but evidence about this assertion is sparse. We analysed data from 73 462 respondents to two English Cancer Patient Experience Surveys to examine whether patients with three or more (3+) pre-referral consultations were more likely to report negative experiences of subsequent care compared with patients with one or two consultations in respect of 12 a priori selected survey questions. For each of 12 experience items, logistic regression models were used, adjusting for prior consultation category, cancer site, socio-demographic case-mix and response tendency (to capture potential variation in critical...

  7. Scenes, Spaces, and Memory Traces: What Does the Hippocampus Do?

    Maguire, EA; Intraub, H; Mullally, SL
    The hippocampus is one of the most closely scrutinized brain structures in neuroscience. While traditionally associated with memory and spatial cognition, in more recent years it has also been linked with other functions, including aspects of perception and imagining fictitious and future scenes. Efforts continue apace to understand how the hippocampus plays such an apparently wide-ranging role. Here we consider recent developments in the field and in particular studies of patients with bilateral hippocampal damage. We outline some key findings, how they have subsequently been challenged, and consider how to reconcile the disparities that are at the heart of current...

  8. Sarcopenic obesity and risk of new onset depressive symptoms in older adults: English Longitudinal Study of Ageing

    Hamer, M; Batty, GD; Kivimaki, M
    We examined the role of sarcopenic obesity as a risk factor for new-onset depressive symptoms over 6-year follow-up in a large sample of older adults.

  9. Interactions between dorsal and ventral streams for controlling skilled grasp

    van Polanen, V; Davare, M
    The two visual systems hypothesis suggests processing of visual information into two distinct routes in the brain: a dorsal stream for the control of actions and a ventral stream for the identification of objects. Recently, increasing evidence has shown that the dorsal and ventral streams are not strictly independent, but do interact with each other. In this paper, we argue that the interactions between dorsal and ventral streams are important for controlling complex object-oriented hand movements, especially skilled grasp. Anatomical studies have reported the existence of direct connections between dorsal and ventral stream areas. These physiological interconnections appear to be...

  10. Is waveform worth it? A comparison of LiDAR approaches for vegetation and landscape characterisation

    Disney, MI; Anderson, K; Hancock, S; Gaston, KJ
    Light Detection And Ranging (LiDAR) systems are frequently used in ecological studies to measure vegetation canopy structure. Waveform LiDAR systems offer new capabilities for vegetation modelling by measuring the time-varying signal of the laser pulse as it illuminates different elements of the canopy, providing an opportunity to describe the 3D structure of vegetation canopies more fully. This paper provides a comparison between waveform airborne laser scanning (ALS) data and discrete return ALS data using terrestrial laser scanning (TLS) data as an independent validation. With reference to two urban landscape typologies we demonstrate that discrete return ALS data provided more biased...

  11. Negotiating failure: Understanding the geopolitics of climate change

    Byrne, A; Maslin, M

  12. Locally rigid, vessel-based registration for laparoscopic liver surgery

    Song, Y; Totz, J; Thompson, S; Johnsen, S; Barratt, D; Schneider, C; Gurusamy, K; Davidson, B; Ourselin, S; Hawkes, D; Clarkson, MJ
    Purpose: Laparoscopic liver resection has significant advantages over open surgery due to less patient trauma and faster recovery times, yet is difficult for most lesions due to the restricted field of view and lack of haptic feedback. Image guidance provides a potential solution but is challenging in a soft deforming organ such as the liver. In this paper, we therefore propose a laparoscopic ultrasound (LUS) image guidance system and study the feasibility of a locally rigid registration for laparoscopic liver surgery. Methods: We developed a real-time segmentation method to extract vessel centre points from calibrated, freehand, electromagnetically tracked, 2D LUS images....

  13. Unguided Species Delimitation Using DNA Sequence Data from Multiple Loci

    Yang, Z; Rannala, B
    A method was developed for simultaneous Bayesian inference of species delimitation and species phylogeny using the multispecies coalescent model. The method eliminates the need for a user-specified guide tree in species delimitation and incorporates phylogenetic uncertainty in a Bayesian framework. The nearest-neighbor interchange algorithm was adapted to propose changes to the species tree, with the gene trees for multiple loci altered in the proposal to avoid conflicts with the newly proposed species tree. We also modify our previous scheme for specifying priors for species delimitation models to construct joint priors for models of species delimitation and species phylogeny. As in...

  14. The Holocene environmental history of a small coastal lake on the north-eastern Kamchatka Peninsula

    Solovieva, N; Klimaschewski, A; Self, AE; Jones, VJ; Andren, E; Andreev, AA; Hammarlund, D; Lepskaya, EV; Nazarova, L
    A radiocarbon and tephra-dated sediment core from Lifebuoy Lake, located on the north-east coast of Kamchatka Peninsula, was analysed for pollen, spores, diatoms, chironomids and tephra in order to uncover regional environmental history. The 6500-year environmental history of Lifebuoy Lake correlates with the broad regional patterns of vegetation development and climate dynamics with both diatoms and chironomids showing near- synchronous changes. Between c. 6300 and 3900 cal yr BP, the lake ecosystem was naturally enriched, with several Stephanodiscus species dominating the diatom plankton. This natural eutrophication state is likely to be due to a combination of the base-rich catchment geology,...

  15. What are the true clusters?

    Hennig, CM
    Constructivist philosophy and Hasok Chang's active scientific realism are used to argue that the idea of ``truth'' in cluster analysis depends on the context and the clustering aims. Different characteristics of clusterings are required in different situations. Researchers should be explicit about on what requirements and what idea of ``true clusters'' their research is based, because clustering becomes scientific not through uniqueness but through transparent and open communication. The idea of ``natural kinds'' is a human construct, but it highlights the human experience that the reality outside the observer's control seems to make certain distinctions between categories inevitable. Various desirable...

  16. Understanding “influence”: An empirical test of the Data-Frame theory of Sensemaking

    Pontis, S; Blandford, AE
    This paper reports findings from a study designed to gain broader understanding of sensemaking activities using the Data/Frame Theory (Klein et al., 2007) as the analytical framework. Although this theory is one of the dominant models of sensemaking, it has not been extensively tested with a range of sensemaking tasks. The tasks discussed here focused on making sense of structures rather than processes or narratives. Eleven researchers were asked to construct understanding of how a scientific community in a particular domain is organized (e.g. people, relationships, contributions, factors) by exploring the concept of “influence” in academia. This topic was chosen...

  17. Cultural factors that affected the spatial and temporal epidemiology of kuru

    Whitfield, JT; Pako, WH; Collinge, J; Alpers, MP
    Kuru is a prion disease which became epidemic among the Fore and surrounding linguistic groups in Papua New Guinea, peaking in the late 1950s. It was transmitted during the transumption (endocannibalism) of dead family members at mortuary feasts. In this study, we aimed to explain the historical spread and the changing epidemiological patterns of kuru by analysing factors that affected its transmission. We also examined what cultural group principally determined a family's behaviour during mortuary rituals. Our investigations showed that differences in mortuary practices were responsible for the initial pattern of the spread of kuru and the ultimate shape of...

  18. What we have changed our minds about: Part 2. Borderline personality disorder, epistemic trust and the developmental significance of social communication

    Fonagy, P; Luyten, P; Allison, E; Campbell, C
    In Part 1 of this paper, we discussed emerging evidence suggesting that a general psychopathology or ‘p’ factor underlying the various forms of psychopathology should be conceptualized in terms of the absence of resilience, that is, the absence of positive reappraisal mechanisms when faced with adversity. These impairments in the capacity for positive reappraisal seem to provide a comprehensive explanation for the association between the p factor and comorbidity, future caseness, and the ‘hard-to-reach’ character of many patients with severe personality pathology, most notably borderline personality disorder (BPD). In this, the second part of the paper, we trace the development...

  19. What we have changed our minds about: Part 1. Borderline personality disorder as a limitation of resilience

    Fonagy, P; Luyten, P; Allison, E; Campbell, C
    This paper sets out a recent transition in our thinking in relation to psychopathology associated with personality disorder, in an approach that integrates our thinking about attachment, mentalizing (understanding ourselves and others in terms of intentional mental states) and epistemic trust (openness to the reception of social communication that is personally relevant and of generalizable significance) with recent findings on the structure of both adult and child psychopathology and resilience. In this paper – the first of two parts – we review evidence suggesting that a general psychopathology or p factor underlies vulnerability for psychopathology. We link this p factor...

  20. Lung, gastric and colorectal cancer mortality by occupation and industry among working-aged men in Japan.

    Eguchi, H; Wada, K; Prieto-Merino, D; Smith, DR
    We examined occupational and industrial differences in lung, gastric, and colorectal cancer risk among Japanese men of working age (25-64 years) using the 2010 Japanese national survey data for occupation and industry-specific death rates. Poisson regression models were used to estimate the age-adjusted incident rate ratios by lung, gastric, and colorectal cancers, with manufacturing used as the referent occupation or industry. Unemployed Japanese men and those in manufacturing had an 8-11-fold increased risk of lung, gastric and colorectal cancer. The highest mortality rates for lung and colorectal cancer by occupation were "administrative and managerial" (by occupation) and "mining" (by industry)....

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