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UCL University College London Eprints (393.499 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 61 - 80 de 392.498

  1. HELP: Star formation as a function of galaxy environment with Herschel

    Duivenvoorden, S; Oliver, S; Buat, V; Darvish, B; Efstathiou, A; Farrah, D; Griffin, M; Hurley, PD; Ibar, E; Jarvis, M; Papadopoulos, A; Sargent, MT; Scott, D; Scudder, JM; Symeonidis, M; Vaccari, M; Viero, MP; Wang, L
    The Herschel Extragalactic Legacy Project (HELP) brings together a vast range of data frommany astronomical observatories. Its main focus is on the Herschel data, which maps dustobscured star formation over 1300 deg2. With this unprecedented combination of data sets, it is possible to investigate how the star formation versus stellar mass relation (main sequence)of star-forming galaxies depends on environment. In this pilot study, we explore this question within 0.1

  2. Common olfactory ensheathing glial markers in the developing human olfactory system

    Oprych, K; Cotfas, D; Choi, D
    The in situ immunocytochemical properties of olfactory ensheathing cells (OECs) have been well studied in several small to medium sized animal models including rats, mice, guinea pigs, cats and canines. However, we know very little about the antigenic characteristics of OECs in situ within the adult and developing human olfactory bulb and nerve roots. To address this gap in knowledge we undertook an immunocytochemical analysis of the 11-19 pcw human foetal olfactory system. Human foetal OECs in situ possessed important differences compared to rodents in the expression of key surface markers. P75(NTR) was not observed in OECs but was strongly expressed...

  3. Flows, system boundaries and the politics of urban metabolism: waste management in Mexico City and Santiago de Chile

    Guibrunet, L; Sanzana Calvet, M; Castan Broto, V
    In this paper we examine two central concepts of urban metabolism (‘system boundaries’ and ‘flows’), and explore how to approach them as a means to politicise urban metabolism research. We present empirical findings from two case studies of waste management, in Mexico City and Santiago de Chile, looking at: the materiality of waste flows, the actors involved in them, and how waste flows relate to issues of environmental justice. We argue that urban metabolism, as a methodology to understand urban sustainability, has the potential to produce knowledge to trigger urban transformations, and to analyse the social, political and environmental aspects...

  4. The Institutionalisation of 'TongNian' and 'childhood' in China and Britain: Exploring Cautious Comparisons

    Ribbens McCarthy, J; Guo, Y; Phoenix, A; Xu, X; Knight, A
    This article engages with the question of how theorisation of the social construction of childhood can be applied across cultural contexts, taking China and Britain as examples. The paper draws on collaborative dialogue between scholars from the People's Republic of China and Britain, and literatures from both Anglophone and Mandarin sources. It takes forward emergent work on theorising childhood from diverse global perspectives by focusing on the institutionalisation of childhood in these countries, with particular reference to language, conceptualisation and legal frameworks relating to chronological age.

  5. Dental Composites with Calcium / Strontium Phosphates and Polylysine

    Panpisut, P; Liaqat, S; Zacharaki, E; Xia, W; Petridis, H; Young, AM
    PURPOSE: This study developed light cured dental composites with added monocalcium phosphate monohydrate (MCPM), tristrontium phosphate (TSrP) and antimicrobial polylysine (PLS). The aim was to produce composites that have enhanced water sorption induced expansion, can promote apatite precipitation and release polylysine. MATERIALS AND METHODS: Experimental composite formulations consisted of light activated dimethacrylate monomers combined with 80 wt% powder. The powder phase contained a dental glass with and without PLS (2.5 wt%) and/or reactive phosphate fillers (15 wt% TSrP and 10 wt% MCPM). The commercial composite, Z250, was used as a control. Monomer conversion and calculated polymerization shrinkage were assessed using FTIR....

  6. Multichannel cross-layer routing for sensor networks

    Nordin, N; Clegg, RG; Rio, M
    This paper proposes a new decentralised multi-channel tree building protocol with a centralised controller for the Internet of Things. The protocol alleviates the effect of interference which results in improved network efficiency and stability, and link reliability. The proposal takes into account all available channels to utilise the spectrum and aims to use the spectrum efficiently by transmitting on several channels. The protocol detects which channels suffer interference and changes away from those channels. The algorithm for channel selection is a two-hop colouring protocol that reduces the chances of nearby nodes to transmit on the same channel. All nodes are...

  7. Analytical Investigations on Carrier Phase Recovery in Dispersion-Unmanaged n-PSK Coherent Optical Communication Systems

    Xu, T; Jacobsen, G; Popov, S; Li, J; Liu, T; Zhang, Y; Bayvel, P
    Using coherent optical detection and digital signal processing, laser phase noise and equalization enhanced phase noise can be effectively mitigated using the feed-forward and feed-back carrier phase recovery approaches. In this paper, theoretical analyses of feed-back and feed-forward carrier phase recovery methods have been carried out in the long-haul high-speed n-level phase shift keying (n-PSK) optical fiber communication systems, involving a one-tap normalized least-mean-square (LMS) algorithm, a block-wise average algorithm, and a Viterbi-Viterbi algorithm. The analytical expressions for evaluating the estimated carrier phase and for predicting the bit-error-rate (BER) performance (such as the BER floors) have been presented and discussed...

  8. The NOURISHED randomised controlled trial comparing mentalization based treatment for eating disorder (MBT-ED) with specialist supportive clinical management (SSCM-ED) for patients with eating disorders and symptoms of Borderline Personality Disorder (BPD)

    Robinson, P; Hellier, J; Barrett, B; Barzdaitiene, D; Bateman, A; Bogaardt, A; Clare, A; Somers, N; O'Callaghan, A; Goldsmith, K; Kern, N; Schmidt, U; Morando, S; Ouellet-Courtois, C; Roberts, A; Skårderud, F; Fonagy, P
    BACKGROUND: In this multi-centre RCT we compared modified Mentalization Based Therapy (MBT-ED) to Specialist Supportive Clinical Management (SSCM-ED) in patients with Eating disorders (ED) and Borderline Personality Disorder symptoms (BPD). This group of patients presents complex challenges to clinical services and a treatment which addresses their multiple problems has the potential to improve outcome. MBT has been shown to be effective in improving outcome in patients with BPD, but its use has not been reported in ED. METHODS: 68 eligible participants were randomised to MBT-ED or SSCM-ED. The primary outcome measure was the Global Score on the Eating Disorders Examination....

  9. A Survey on the Current Status and Future Challenges Towards Objective Skills Assessment in Endovascular Surgery

    Mazomenos, EB; Chang, P-L; Rolls, A; Hawkes, DJ; Bicknell, CD; Poorten, EV; Riga, CV; Desjardins, A; Stoyanov, D
    Minimally-invasive endovascular interventions have evolved rapidly over the past decade, facilitated by breakthroughs in medical imaging and sensing, instrumentation and most recently robotics. Catheter based operations are potentially safer and applicable to a wider patient population due to the reduced comorbidity. As a result endovascular surgery has become the preferred treatment option for conditions previously treated with open surgery and as such the number of patients undergoing endovascular interventions is increasing every year. This fact coupled with a proclivity for reduced working hours, results in a requirement for efficient training and assessment of new surgeons, that deviates from the “see one, do one, teach one”...

  10. Cultural ecosystem services in protected areas: understanding bundles, trade-offs and synergies

    Ament, JM; Moore, CA; Herbst, M; Cumming, GS
    The concept of ecosystem services (ES) provides a potentially useful tool for decision-making in natural area management. Provisioning and regulating ES often occur in “bundles” that are cohesive because of coprovisioning or codependence. We asked whether individual preferences for cultural benefits also define service bundles. Data from a large survey of visitor preferences (n = 3,131 respondents) from all 19 South African National Parks indicated five bundles of cultural ecosystem services: (1) “natural history,” (2) “recreation,” (3) “sense of place,” (4) “safari experiences,” and (5) “outdoor lifestyle.” Trade-offs and synergies between bundles of services depended on the ecosystem providing them...

  11. Letter to the Editor: A reply – acknowledged reasonable limitations in a secondary analysis but key conclusions remain in ‘The neural basis of flashback formation: the impact of viewing trauma’

    Clark, IA; MacKay, CE; Holmes, EA; Bourne, C

  12. A Systematic Review of Predictions of Survival in Palliative Care: How Accurate Are Clinicians and Who Are the Experts?

    White, N; Reid, F; Harris, A; Harries, P; Stone, P
    BACKGROUND: Prognostic accuracy in palliative care is valued by patients, carers, and healthcare professionals. Previous reviews suggest clinicians are inaccurate at survival estimates, but have only reported the accuracy of estimates on patients with a cancer diagnosis. OBJECTIVES: To examine the accuracy of clinicians' estimates of survival and to determine if any clinical profession is better at doing so than another. DATA SOURCES: MEDLINE, Embase, CINAHL, and the Cochrane Database of Systematic Reviews and Trials. All databases were searched from the start of the database up to June 2015. Reference lists of eligible articles were also checked. ELIGIBILITY CRITERIA: INCLUSION...

  13. Close-form expression of one-tap normalized LMS carrier phase recovery in optical communication systems

    Xu, T; Jacobsen, G; Popov, S; Li, J; Liu, T; Zhang, Y
    The performance of long-haul high speed coherent optical fiber communication systems is significantly degraded by the laser phase noise and the equalization enhanced phase noise (EEPN). In this paper, the analysis of the one-tap normalized least-mean-square (LMS) carrier phase recovery (CPR) is carried out and the close-form expression is investigated for quadrature phase shift keying (QPSK) coherent optical fiber communication systems, in compensating both laser phase noise and equalization enhanced phase noise. Numerical simulations have also been implemented to verify the theoretical analysis. It is found that the one-tap normalized least-mean-square algorithm gives the same analytical expression for predicting CPR...

  14. Digital adaptive carrier phase estimation in multi-level phase shift keying coherent optical communication systems

    Xu, T; Liu, T; Zhang, Y; Jacobsen, G; Li, J; Popov, S
    The analysis of adaptive carrier phase estimation is investigated in long-haul high speed n-level phase shift keying (n-PSK) optical fiber communication systems based on the one-tap normalized least-mean-square (LMS) algorithm. The close-form expressions for the estimated carrier phase and the bit-error-rate floor have been derived in the n-PSK coherent optical transmission systems. The results show that the one-tap normalized LMS algorithm performs pretty well in the carrier phase estimation, but will be less effective with the increment of modulation levels, in the compensation of both intrinsic laser phase noise and equalization enhanced phase noise.

  15. On the adoption of privacy-enhancing technologies

    Caulfield, T; Ioannidis, C; Pym, D
    We propose a model, based on the work of Brock and Durlauf, which looks at how agents make choices between competing technologies, as a framework for exploring aspects of the economics of the adoption of privacy-enhancing technologies. In order to formulate a model of decision-making among choices of technologies by these agents, we consider the following: context, the setting in which and the purpose for which a given technology is used; requirement, the level of privacy that the technology must provide for an agent to be willing to use the technology in a given context; belief, an agent’s perception of...

  16. A logic for the compliance budget

    Anderson, G; McCusker, G; Pym, D
    Security breaches often arise as a result of users’ failure to comply with security policies. Such failures to comply may simply be innocent mistakes. However, there is evidence that, in some circumstances, users choose not to comply because they perceive that the security benefit of compliance is outweighed by the cost that is the impact of compliance on their abilities to complete their operational tasks. That is, they perceive security compliance as hindering their work. The ‘compliance budget’ is a concept in information security that describes how the users of an organization’s systems determine the extent to which they comply...

  17. Effect of diurnal variation, CYP2B6 genotype and age on the pharmacokinetics of nevirapine in African children

    Bienczak, A; Cook, A; Wiesner, L; Mulenga, V; Kityo, C; Kekitiinwa, A; Walker, AS; Owen, A; Gibb, DM; Burger, D; McIlleron, H; Denti, P
    OBJECTIVES: To characterize the effects of CYP2B6 polymorphisms, diurnal variation and demographic factors on nevirapine pharmacokinetics in African children. METHODS: Non-linear mixed-effects modelling conducted in NONMEM 7.3 described nevirapine plasma concentration-time data from 414 children aged 0.3-15 years. RESULTS: Nevirapine pharmacokinetics was best described using a one-compartment disposition model with elimination through a well-stirred liver model accounting for a first-pass effect and transit-compartment absorption. Intrinsic clearance was affected by diurnal variation (characterized using a cosine function with peak amplitude 29% at 12 noon) and CYP2B6 metabolizer status [extensive metabolizer (EM) 516GG|983TT, reference; intermediate metabolizer (IM) 516GT|983TT or 516GG|983TC, 17% lower;...

  18. A randomised controlled trial of mentalization-based treatment versus structured clinical management for patients with comorbid borderline personality disorder and antisocial personality disorder.

    Bateman, A; O'Connell, J; Lorenzini, N; Gardner, T; Fonagy, P
    BACKGROUND: Antisocial personality disorder (ASPD) is an under-researched mental disorder. Systematic reviews and policy documents identify ASPD as a priority area for further treatment research because of the scarcity of available evidence to guide clinicians and policymakers; no intervention has been established as the treatment of choice for this disorder. Mentalization-based treatment (MBT) is a psychotherapeutic treatment which specifically targets the ability to recognise and understand the mental states of oneself and others, an ability shown to be compromised in people with ASPD. The aim of the study discussed in this paper is to investigate whether MBT can be an...

  19. A Simultaneous Equation Approach to Estimating HIV Prevalence with Non-Ignorable Missing Responses

    Marra, G; Radice, R; Barnighausen, T; Wood, SN; McGovern, ME
    Estimates of HIV prevalence are important for policy in order to establish the health status of a country's population and to evaluate the effectiveness of population-based interventions and campaigns. However, participation rates in testing for surveillance conducted as part of household surveys, on which many of these estimates are based, can be low. HIV positive individuals may be less likely to participate because they fear disclosure, in which case estimates obtained using conventional approaches to deal with missing data, such as imputation-based methods, will be biased. We develop a Heckman-type simultaneous equation approach which accounts for non-ignorable selection, but unlike...

  20. A synthetic biology standard for Chinese Hamster Ovary cell genome monitoring and contaminant detection by polymerase chain reaction.

    Templar, A; Marsh, D; Nesbeth, DN
    BACKGROUND: Chinese Hamster Ovary (CHO) cells are the current industry standard for production of therapeutic monoclonal antibodies at commercial scales. Production optimisation in CHO cells hinges on analytical technologies such as the use of the polymerase chain reaction (PCR) to quantify genetic factors within the CHO genome and to detect the presence of contaminant organisms. PCR-based assays, whilst sensitive and accurate, are limited by (i) requiring lengthy sample preparation and (ii) a lack of standardisation. RESULTS: In this study we directly assess for the first time the effect of CHO cellular material on quantitative PCR (qPCR) and end-point PCR (e-pPCR)...

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