Sites In Central London Research Articles

Back-analysis of an embedded retaining wall in stiff clay

The performance of embedded retaining walls during and after excavation is commonly predicted using numerical techniques and assessed by field monitoring. However, subsequent back-analyses of post-construction monitoring data are rarely undertaken. The purpose of this paper is two-fold: (a) to provide a comprehensive post-construction review of site information and monitoring data from a construction site in central London and (b) to detail results from a parametric study undertaken as part of the back-analyses of five key embedded retaining wall sections. The importance of accounting for the effects of non-linear soil stiffness when predicting wall deflection profiles is highlighted by the parametric study. Good agreement between the numerical model and field monitoring data was achieved through the back-analysis exercise. Differences in the predicted class C wall deflection profiles are attributed to varying temporary support systems and complex three-dimensional site geometry. Best practice recommendations relating to field monitoring and a new streamlined methodology for performing similar back-analyses are proposed.

Measurement report: MAX-DOAS measurements characterise Central London ozone pollution episodes during 2022 heatwaves

Abstract. Heatwaves are a substantial health threat in the UK, exacerbated by co-occurrence of ozone pollution episodes. Here we report on the first use of retrieved vertical profiles of nitrogen dioxide (NO2) and formaldehyde (HCHO) over Central London from a newly installed multi-axis differential optical absorption spectroscopy (MAX-DOAS) instrument coincident with two of three heatwaves for the hottest summer on record. We evaluate space-based sensor observations routinely used to quantify temporal changes in air pollution and precursor emissions over London. Collocated daily mean tropospheric column densities from the high-spatial-resolution space-based TROPOspheric Monitoring Instrument (TROPOMI) and MAX-DOAS, after accounting for differences in vertical sensitivities, are temporally consistent for NO2 and HCHO (both R = 0.71). TROPOMI NO2 is 27 %–31 % less than MAX-DOAS NO2, as expected from horizontal dilution of NO2 by TROPOMI pixels in polluted cities. TROPOMI HCHO is 20 % more than MAX-DOAS HCHO, greater than differences in past validation studies but within the range of systematic errors in the MAX-DOAS retrieval. The MAX-DOAS near-surface (0–110 m) retrievals have similar day-to-day and hourly variability to the surface sites for comparison of NO2 (R ≥ 0.7) and for MAX-DOAS HCHO versus surface site isoprene (R ≥ 0.7) that oxidises to HCHO in prompt and high yields. Daytime ozone production, diagnosed with MAX-DOAS HCHO-to-NO2 tropospheric vertical column ratios, is mostly limited by availability of volatile organic compounds (VOCs), except on heatwave days. Temperature-dependent biogenic VOC emissions of isoprene increase exponentially, resulting in ozone concentrations that exceed the regulatory standard for ozone and cause non-compliance at urban background sites in Central London. Locations in Central London heavily influenced by traffic remain in compliance, but this is likely to change with stricter controls on vehicle emissions of NOx and higher likelihood of heatwave frequency, severity, and persistence due to anthropogenic climate change.

Composition and emission factors of traffic- emitted intermediate volatility and semi-volatile hydrocarbons (C10–C36) at a street canyon and urban background sites in central London, UK

Abstract Hydrocarbons in both gas and particle phases from C10 to C36 (I/SVOCs) were analysed at sites in central London. Samples were collected from a street canyon, Marylebone Road (MR), a rooftop site (WM) above MR, and a site in the adjacent Regent's Park (RU), north of MR to evaluate the change in composition of I/SVOCs during advection from the traffic to the cleaner atmosphere of the urban background. Groups of compounds identified and quantified in gas and particle phases include C13–C36 n-alkanes and branched alkanes, C12–C25 monocyclic alkanes, C13–C27 bicyclic alkanes and C10–C24 monocyclic aromatics. The similarities found in the aliphatic and aromatic region above C12 in urban air and diesel exhaust demonstrate the impact of diesel-powered vehicles on urban air quality. Diesel exhaust is suggested to be the dominant emission source, while small differences between sites indicate the possibility of other sources which are also discussed. The ambient concentrations of I/SVOCs in the street canyon at MR were highest when the southerly winds brought the traffic emitted pollutants to the sampler. Emission factors (EFs) for all compound groups were estimated from the concentrations at the MR site. Particle-phase n-alkane EFs are broadly similar to those measured elsewhere in the world, despite differences in traffic fleet composition. A comparison between n-alkane EFs estimated from field measurements and those measured from diesel engines in the laboratory suggests a large contribution from vehicles with higher emissions than recent passenger cars to London air.

Spatial estimation of outdoor NO2 levels in Central London using deep neural networks and a wavelet decomposition technique

Outdoor air pollution remains a major environmental threat to the public, especially those who reside in highly urbanised areas. Recent studies have revealed the effectiveness of early-warning mechanisms that enable the public reduce their exposure to air pollutants. This highlights the need for accurate air quality forecasts. However, air quality in many developing and highly urbanised countries remains unmonitored. Hence, a novel spatiotemporal interpolation modelling approach based on a deep learning and wavelet pre-processing technique was proposed in this paper. In more detail, Long Short-term Memory (LSTM) neural networks and Discrete Wavelet Transformation (DWT) were utilised to model the spatial variability of hourly NO2 levels at six urban sites in Central London, the United Kingdom. The models were trained using only the NO2 concentration data from the neighbouring sites. Benchmark models such as plain LSTM and Multilayer Perceptron (MLP) models were also developed to validate the effectiveness of the proposed models. The proposed wavelet-based spatiotemporal models were found to provide superior forecasting results, explaining 77% to 93% of the variability of the actual NO2 concentration levels at most sites. The overall results reveal the very promising potential of the proposed models for the spatiotemporal characterisation of outdoor air pollution.

Short- and long-term forecasting of ambient air pollution levels using wavelet-based non-linear autoregressive artificial neural networks with exogenous inputs

Roadside air pollution is a major issue due to its adverse effects on human health and the environment. This highlights the need for parsimonious and robust forecasting tools that help vulnerable members of the public reduce their exposure to harmful air pollutants. Recent results in air pollution forecasting applications include the use of hybrid models based on non-linear autoregressive artificial neural networks (ANN) with exogenous multi-variable inputs (NARX) and wavelet decomposition techniques. However, attempts employing both methods into one hybrid modelling system have not been widely made. Hence, this work further investigates the utilisation of wavelet-based NARX-ANN models in the shortand long-term prediction of hourly NO2 concentration levels. The models were trained using emissions and meteorological data collected from a busy roadside site in Central London, United Kingdom from January to December 2015. A discrete wavelet transformation technique was then implemented to address the highly variable characteristic of the collected NO2 concentration data. Overall results exhibit the superiority of the wavelet-based NARX-ANN models improving the accuracy of the benchmark NARX-ANN model results by up to 6% in terms of explained variance. The proposed models also provide fairly accurate long-term forecasts, explaining 68–76% of the variance of actual NO2 data. In conclusion, the findings of this study demonstrate the high potential of wavelet-based NARX-ANN models as alternative tools in short- and long-term forecasting of air pollutants in urban environments.

Observed aerosol characteristics to improve forward-modelled attenuated backscatter in urban areas

Numerical weather prediction (NWP) models often parameterise aerosols to reduce computational needs, while aiming to accurately capture their impact adequately. Increasingly, aerosols are monitored in-situ directly and/or indirectly (e.g. by automatic lidars and ceilometers, ALC). ALC measure the aerosol optical characteristic of attenuated backscatter. This can also be estimated using forward models that combine forecast aerosol and relative humidity to parameterise aerosol physical and optical characteristics. The aerFO is one such forward model, designed to use Met Office NWP model output and parameterisations from the MURK visibility scheme. Given the aerFO-MURK scheme link, assessing the aerFO output could help inform future MURK scheme developments. To identify which parameterised physical and optical aerosol characteristics in the scheme are the most critical in urban settings, aerFO is driven with different in-situ aerosol observations at a background site in central London. Estimated attenuated backscatter is assessed against ALC observations. It is shown that the original MURK scheme parameterisation underestimates the variance of both dry mean volume radius and total number concentration. Representing both the accumulation and coarse mode aerosols in the aerFO reduces the median bias error of estimated attenuated backscatter by 69.1%. Providing more realistic temporal (monthly to hourly) variability of relative mass for different species leads to little improvement, compared to using monthly climatological means. Numerical experiments show that having more realistic estimates of number concentration is more important than providing more accurate values of the dry mean volume radius for the accumulation mode. Hence, improving the parameterisations for number concentration should be a main focus for further development of the MURK scheme. To estimate aerosol attenuated backscatter, the aerFO requires an extinction to backscatter ratio (i.e. the lidar ratio). In addition to forward modelling, the lidar ratio can also be used with ALC attenuated backscatter to calculate aerosol properties estimated in aerosol forecasts. Here, a model is developed that estimates the ratio using in-situ observations of the number size distribution and speciated aerosol masses. The values of lidar ratio derived at the London background site (14–80 sr across selected common lidar wavelengths) compare well to the literature. However, the modelled lidar ratio is unexpectedly correlated to relative humidity. Further, a stronger dependence exists at shorter wavelengths (355 and 532 nm) compared to longer wavelengths (905 and 1064 nm), and is due to the critical relation of lidar wavelength to aerosol size.

Proximal Humerus Fractures in Children: Experience from a Central London Paediatric Orthopaedic Service

Objective: Proximal humeral fractures are commonly observed in children who sustain falls whilst running, or from heights. Appropriate and correct treatment is key in order to avoid limb length discrepancy and functional deficiencies. Current treatment methods include non-operative management such as collar and cuff immobilisation, and operative methods such as elastic stable intramedullary nails or Kirschner wires. This paper aims to present the demographics of this patient population and our experience in managing patients with proximal humerus fractures in an urban tertiary referral centre. Method: We assessed 41 cases across two sites in central London, identified via hospital electronic notes and our radiology digital system. We analysed patient demographics, mechanism of injury, time to discharge from orthopaedic services taking into account radiological and clinical union, and the treatment methods utilised. Results: The mean age of the cohort was 8.6 years old. 70% of the injuries were due to falls and 85% of cases were treated without an operation. The mean time to discharge from our service following radiological and clinical union was 46 days (9 – 161 days). Mean radiological and clinical union were 21.8 and 36.2 days respectively. Conclusion: These results support a non-operative approach, especially in cases with patients under 10 years of age. Surgery should only be undertaken in patients who have severe displacement and who have failed attempts at closed reduction. We would advocate a similar approach in institutions dealing with a comparable population of patients, as long as there are provisions for referral of more complex cases that require surgical stabilisation.

Publics and their Problems: Notes on the Remaking of the South Bank, London

AbstractCities are full of disputes about organizing public life. These disputes are important for deciding how spaces get used, and they are integral to how publics form and develop. In all sorts of ways they define the potentialities of urban public life. This article tells the story of the Southbank Centre's plans to redevelop their central London site, and Long Live Southbank's protest of these plans to save their skateable space. Through this detailed case study the article develops a distinctive conceptual apparatus for making sense of public disputes. Drawing links between Deweyan pragmatism and assemblage theory, the article explores how publics were drawn together as assemblages of humans and non‐humans with the capacity to act and argue. It follows the arguments that each side made—and the justifications underpinning them—to explore the different ideas of public‐ness that were at stake in the disagreement. This also helps highlight the space for cooperation that existed. The article emphasizes the part affect played in shaping the dispute; recognizing its role in public reasoning, and in how people get pulled into different publics. This is a story not only of disputation, but of how a corner of London expanded its public‐ness.

Shedding light on ancient secrets [cryptology of ancient documents

Many ancient texts have kept their secrets for centuries. But a host of low-tech and high-tech tools are helping cryptologists to reveal the past.WHEN ALAN TURING developed the machine that helped to crack the Enigma code, his aim was to understand messages that the Nazis wanted to keep secret. When ancient writing expert Roger Tomlin came across wooden tablets found recently at an excavation site in central London, he knew the words - now mere scratches on wood but originally marked in beeswax with a metal stylus almost 2,000 years ago - were not meant to be a secret. However, it took him a year to decipher them. The tablets are the oldest handwritten documents found in the UK, detailing financial transactions and events in early London, starting a few years after the Roman invasion of Britain; they even mention events related to the revolt of Queen Boudica of the Celtic Iceni tribe in what is now East Anglia, who stood up against the occupying forces of the Roman Empire.

Model simulations of cooking organic aerosol (COA) over the UK using estimates of emissions based on measurements at two sites in London

Abstract. Cooking organic aerosol (COA) is currently not included in European emission inventories. However, recent positive matrix factorization (PMF) analyses of aerosol mass spectrometer (AMS) measurements have suggested important contributions of COA in several European cities. In this study, emissions of COA were estimated for the UK, based on hourly AMS measurements of COA made at two sites in London (a kerbside site in central London and an urban background site in a residential area close to central London) for the full calendar year of 2012 during the Clean Air for London (ClearfLo) campaign. Iteration of COA emissions estimates and subsequent evaluation and sensitivity experiments were conducted with the EMEP4UK atmospheric chemistry transport modelling system with a horizontal resolution of 5 km × 5 km. The spatial distribution of these emissions was based on workday population density derived from the 2011 census data. The estimated UK annual COA emission was 7.4 Gg per year, which is an almost 10 % addition to the officially reported UK national total anthropogenic emissions of PM2.5 (82 Gg in 2012), corresponding to 320 mg person−1 day−1 on average. Weekday and weekend diurnal variation in COA emissions were also based on the AMS measurements. Modelled concentrations of COA were then independently evaluated against AMS-derived COA measurements from another city and time period (Manchester, January–February 2007), as well as with COA estimated by a chemical mass balance model of measurements for a 2-week period at the Harwell rural site (∼ 80 km west of central London). The modelled annual average contribution of COA to ambient particulate matter (PM) in central London was between 1 and 2 µg m−3 (∼ 20 % of total measured OA1) and between 0.5 and 0.7 µg m−3 in other major cities in England (Manchester, Birmingham, Leeds). It was also shown that cities smaller than London can have a central hotspot of population density of smaller area than the computational grid cell, in which case higher localized COA concentrations than modelled here may be expected. Modelled COA concentrations dropped rapidly outside of major urban areas (annual average of 0.12 µg m−3 for the Harwell location), indicating that although COA can be a notable component in urban air, it does not have a significant effect on PM concentrations on rural areas. The possibility that the AMS-PMF apportionment measurements overestimate COA concentrations by up to a factor of 2 is discussed. Since COA is a primary emission, any downward adjustments in COA emissions would lead to a proportional linear downward scaling in the absolute magnitudes of COA concentrations simulated in the model.

Conversion of simulated radioactive pollutant gas concentrations for a complex building array into radiation dose

Methods used to convert wind tunnel and ADMS concentration field data for a complex building array into effective radiation dose were developed based on simulations of a site in central London. Pollutant source terms were from positron emitting gases released from a cyclotron and clinical PET radiotracer facility. Five years of meteorological data were analysed to determine the probability distribution of wind direction and speed. A hemispherical plume cloud model (both static and moving) was developed which enabled an expression of gamma-ray dose, taking into account build-up factors in air, in terms of analytic functions in this geometry. The standard building wake model is presented, but this is extended and developed in a new model to cover the concentration field in the vicinity of a roof top structure recirculation zone, which is then related to the concentration in the main building wake zone. For all models presented the effective dose was determined from inhalation, positron cloud immersion and gamma ray plume contributions. Results of applying these models for determination of radiation dose for a particular site are presented elsewhere.

Dispersion of positron emitting radioactive gases in a complex urban building array: a comparison of dose modelling approaches

A radiological assessment was carried out on the release of positron-emitting radioactive gases from a roof-level stack at a central London site. Different modelling approaches were performed to investigate the range of radiation doses to representative persons. Contributions from plume inhalation, gamma shine and immersion to effective dose were taken into account. Dry and wet surface deposition on the roof, and exposure from contamination on the skin of roof-workers, added only a mean 4.7% to effective dose and were neglected. A 1:200 scale model, consisting of the stack and surrounding buildings, was tested in a wind tunnel to simulate pollutant dispersion in the near-field region i.e. rooftop. Concentration field measurements in the wind tunnel were converted into effective dose, including for roof-workers installing glass cladding to the stack building. Changes in the building shape, from addition of the cladding layer, were investigated in terms of the near-field flow pattern and significant differences found between the two cases. Pollutant concentrations were also modelled using Air Dispersion Modelling System (ADMS) and the results used to calculate the effective dose using the same meteorological data set and source release terms. Sector averaged wind tunnel dose estimates were greater than the ADMS figure by approximately a factor of two to three. Different stack release heights were investigated in the wind tunnel and ADMS simulations in order to determine the best height for the replacement flue stack for the building. Other techniques were investigated: building wake models, modified Gaussian plume methods and uniform dilution into a hemispherical volume to show the wide variation in predicted dose possible with different approaches. Large differences found between simpler analytic approaches indicated that more robust radiological assessments, based on more complex modelling approaches, were required to achieve satisfactory estimates of radiation dose to representative groups in adjacent buildings and on the building rooftop.

Seasonal and diurnal trends in concentrations and fluxes of volatile organic compounds in central London

Abstract. Concentrations and fluxes of seven volatile organic compounds (VOCs) were measured between August and December 2012 at a rooftop site in central London as part of the ClearfLo project (Clean Air for London). VOC concentrations were quantified using a proton transfer reaction mass spectrometer (PTR-MS) and fluxes were calculated using a virtual disjunct eddy covariance technique. The median VOC fluxes, including aromatics, oxygenated compounds and isoprene, ranged from 0.07 to 0.33 mg m−2 h−1. Median mixing ratios were 7.3 ppb for methanol and < 1 ppb for the other compounds. Strong relationships were observed between the fluxes and concentrations of some VOCs with traffic density and between the fluxes and concentrations of isoprene and oxygenated compounds with photosynthetically active radiation (PAR) and temperature. An estimated 50–90 % of the fluxes of aromatic VOCs were attributable to traffic activity, which showed little seasonal variation, suggesting that boundary layer effects or possibly advected pollution may be the primary causes of increased concentrations of aromatics in winter. Isoprene, methanol and acetaldehyde fluxes and concentrations in August and September showed high correlations with PAR and temperature, when fluxes and concentrations were largest suggesting that biogenic sources contributed to their fluxes. Modelled biogenic isoprene fluxes from urban vegetation using the Guenther et al. (1995) algorithm agreed well with measured fluxes in August and September. Comparisons of estimated annual benzene emissions from both the London and the National Atmospheric Emissions Inventories agreed well with measured benzene fluxes. Flux footprint analysis indicated emission sources were localised and that boundary layer dynamics and source strengths were responsible for temporal and spatial VOC flux and concentration variability during the measurement period.

P121 A review of the telephone advice service for central and north west london integrated sexual health services

Background/introduction Although not advertised patients can phone our integrated sexual health services for advice and receive a call-back within 24 h. This service takes up significant resources without being funded. Aim(s)/objectives Review the reasons for advice calls and establish their outcomes. Methods A notes review was conducted of 50 calls received at each of the 3 main clinical sites in Central London over a 2 week period in July 2014. Data was collected regarding the reason for the phone call, call outcome and attendance within 6 weeks following the call. Results The majority 129/150(86%) of calls were from existing patients. The majority of phone advice was related to contraception n = 44/160(28%), advice on sexually transmitted infections n = 22/160(14%) and patients with symptoms n = 31/160(19%). 24/44(66%) of the contraception calls were for intrauterine device (IUD) advice (pre-and post-insertion). 50/150(33%) patients were advised to attend the clinic of whom 39/50(78%) did attend. 66/150(44%) patients were given reassurance of whom 12/66(18%) attended anyway related to their call. Discussion The phone advice service was largely used by existing users and almost 40% attended the service after the phone call. To make more effective use of resources we have designed frequently answered questions (FAQ) page on our website to address the most commonly asked questions. Phone advice is now only available to patients on post-exposure prophylaxis (PEP) and post-procedure eg. IUD insertion.

Concentrations of selected volatile organic compounds at kerbside and background sites in central London

Ground-level concentrations of nine volatile organic compounds (VOCs) were measured using a proton transfer reaction-mass spectrometer (PTR-MS) in central London at an urban background (North Kensington, NK, during 16th–25th Jan 2012) and a kerbside site (Marylebone Rd, MRd, during 25th Jan–7th Feb 2012) as part of the winter intensive observation period of the ClearfLo project. Site comparisons indicated that VOC concentrations at the urban background site were significantly lower than at the kerbside site (ratio MRd/NK of 2.3). At the kerbside site PTR-MS measurements of aromatics (benzene, toluene, C2- and C3-benzenes) were compared with the gas chromatography – flame ionization detector data from the UK Government's Automatic Hydrocarbon Network. Very good qualitative agreement was observed between the two methods (r = 0.90–0.91, p < 0.001, N = 260), although there was a significant offset between the instruments. This was partly due to issues with humidity dependent background measurements, but possibly also from isobaric interference of other compounds and their fragments, giving a positive bias to the PTR-MS data. Most compounds showed strong indications of traffic-related sources with double rush hour peaks in diurnal profiles and high correlations with known traffic-related compounds (r = 0.68–0.97 at NK, 0.48–0.87 at MRd, p < 0.001, NNK = 2202–2227, NMRd = 2705–2720) and CO (r = 0.80–0.96 at NK, 0.65–0.84 at MRd, p < 0.001, NNK = 223, NMRd = 256–274). Polar plots agreed with statistical analysis of wind direction dependency and identification of potential emission sources was attempted.

FRII-06 FROM LISTER TO LAPAROSCOPY: 100 YEARS OF UROLOGY IN SOUTH EAST LONDON

You have accessJournal of UrologyHistory of Urology II (Moderated Poster)1 Apr 2014FRII-06 FROM LISTER TO LAPAROSCOPY: 100 YEARS OF UROLOGY IN SOUTH EAST LONDON jonathan Makanjuola, Ian Dickinson, Andrew Yates-Bell, John Philpott-Howard, and Peter Thompson jonathan Makanjuolajonathan Makanjuola More articles by this author , Ian DickinsonIan Dickinson More articles by this author , Andrew Yates-BellAndrew Yates-Bell More articles by this author , John Philpott-HowardJohn Philpott-Howard More articles by this author , and Peter ThompsonPeter Thompson More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1744AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail Introduction and Objectives In 1909 Edward the Seventh laid the foundation stone of the third King’s College Hospital and it opened in 1913 in Camberwell in south east London in the UK. It had moved from its site in central London as the population around the hospital was declining. The history of 100 years of urology at King’s uniquely captures the time and the evolution of the speciality Methods Primary and secondary sources were studied from documents, archives and interviews relating to the history of the urology department at King’s College Hospital. The results are presented. Results Lord Lister was appointed to King’s in 1877. It was his understanding and introduction of antisepsis that revolutionised surgical practice. This was continued at King’s by his disciples led famously by Sir William Watson Cheyne. The urology department was established by Sir John Thomson-Walker the most respected urologist of the day. He was an advocate for Sir Peter Freyer and further refined the transvesical prostatectomy. He also wrote the classic urological textbook of the day. John Everidge and Geoffrey Yates-Bell were junior colleagues and later went on to be instrumental in the establishment of the British Urological Association from the Royal Society of Medicine. Geoffrey Yates-Bell led in the introduction of the Millin’s prostatectomy and travelled to the west coast of America to demonstrate the procedure. He was succeeded by his son Andrew Yates-Bell, who was able to continue the links with the Royal Society of Medicine and tradition in teaching and training. The appointment of John Pryor led to the establishment of Andrology both at King’s and the Institute of Urology. Links were established with Professor Giles Brindley from the Department of Neurosciences which resulted in a number of new and novel treatments for erectile dysfunction.In 1994 the late Malcolm Coptcoat performed the first laparoscopic nephrectomy in Europe at King’s College Hospital. This has led to the establishment of a training programme in minimally invasive surgery, which still continues today. Conclusions This paper chronicles the history of the department of urology at King’s College Hospital, London in the UK and highlights the events and the surgeons who have helped develop urology into the speciality that we recognise today. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e629 Advertisement Copyright & Permissions© 2014MetricsAuthor Information jonathan Makanjuola More articles by this author Ian Dickinson More articles by this author Andrew Yates-Bell More articles by this author John Philpott-Howard More articles by this author Peter Thompson More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...

Height Aiding, C/N0 Weighting and Consistency Checking for GNSS NLOS and Multipath Mitigation in Urban Areas

Multiple global navigation satellite system (GNSS) constellations can dramatically improve the signal availability in dense urban environments. However, accuracy remains a challenge because buildings block, reflect and diffract the signals. This paper investigates three different techniques for mitigating the impact of non-line-of-sight (NLOS) reception and multipath interference on position accuracy without using additional hardware, testing them using data collected at multiple sites in central London. Aiding the position solution using a terrain height database was found to have the biggest impact, improving the horizontal accuracy by 35% and the vertical accuracy by a factor of 4. An 8% improvement in horizontal accuracy was also obtained from weighting the GNSS measurements in the position solution according to the carrier-power-to-noise-density ratio (C/N0). Consistency checking using a conventional sequential elimination technique was found to degrade horizontal positioning performance by 60% because it often eliminated the wrong measurements in cases when multiple signals were affected by NLOS reception or strong multipath interference. A new consistency checking method that compares subsets of measurements performed better, but was still equally likely to improve or degrade the accuracy. This was partly because removing a poor measurement can result in adverse signal geometry, degrading the position accuracy. Based on this, several ways of improving the reliability of consistency checking are proposed.

Identification of Micro-scale Anthropogenic CO2, heat and moisture sources – Processing eddy covariance fluxes for a dense urban environment

Anthropogenic emissions of heat and exhaust gases play an important role in the atmospheric boundary layer, altering air quality, greenhouse gas concentrations and the transport of heat and moisture at various scales. This is particularly evident in urban areas where emission sources are integrated in the highly heterogeneous urban canopy layer and directly linked to human activities which exhibit significant temporal variability. It is common practice to use eddy covariance observations to estimate turbulent surface fluxes of latent heat, sensible heat and carbon dioxide, which can be attributed to a local scale source area. This study provides a method to assess the influence of micro-scale anthropogenic emissions on heat, moisture and carbon dioxide exchange in a highly urbanized environment for two sites in central London, UK. A new algorithm for the Identification of Micro-scale Anthropogenic Sources (IMAS) is presented, with two aims. Firstly, IMAS filters out the influence of micro-scale emissions and allows for the analysis of the turbulent fluxes representative of the local scale source area. Secondly, it is used to give a first order estimate of anthropogenic heat flux and carbon dioxide flux representative of the building scale. The algorithm is evaluated using directional and temporal analysis. The algorithm is then used at a second site which was not incorporated in its development. The spatial and temporal local scale patterns, as well as micro-scale fluxes, appear physically reasonable and can be incorporated in the analysis of long-term eddy covariance measurements at the sites in central London. In addition to the new IMAS-technique, further steps in quality control and quality assurance used for the flux processing are presented. The methods and results have implications for urban flux measurements in dense urbanised settings with significant sources of heat and greenhouse gases.

Escherichia coli contamination of the river Thames in different seasons and weather conditions

AbstractContamination of public water ways with sewage represents a serious environmental and health risk. We monitored pollution of the river Thames by enumerating the indicator organism Escherichia coli. Samples were taken from a site in central London near Waterloo Bridge in different seasons. E. coli were quantified using a membrane filtration method, and correlated with the tidal variations of the river and meteorological data on rainfall and temperature. More frequent and severe incidents of pollution occurred in the autumn. Heavy rainfall resulted in sharp peaks of E. coli contamination that implies a potential increase of numbers of pathogenic micro‐organisms. Sixty percent of all samples were found to be in excess of the accepted upper limit of pollution set by European Union (EU) legislation for bathing water. This study demonstrated that frequent sewage pollution of the Thames results in high numbers of E. coli and incidents of detectable levels of pathogenic bacteria demonstrating the need for regular monitoring of bacterial pollution.

Music for the multitude: accounts of brass bands entering Enderby Jackson's Crystal Palace contests in the 1860s

Jackson, one of the most talented musical entrepreneurs of the mid-Victorian period, claimed to have invented the brass band contest. One of his major achievements was the establishment of contests held at the Crystal Palace in Sydenham, on the outskirts of London, between 1860 and 1863. They brought mass audiences to the edifice, which had been moved from its original site in central London. One of the main purposes of the event was to contribute to the establishment of the new venue as a center for entertainment at a national rather than a merely local level. Jackson was a brilliant commercial strategist who based his organizational method on meticulous planning. Each band wishing to enter the contest was required to complete a form that detailed critical information about its musical and social identity. Seventy-five of these forms survive in the care of the Edinburgh University Collection of Historic Musical Instruments, and they provide a rich and intimate source of information on the instrumentation, repertoire, and social framework of bands of the period. Taken with information about the reception of the events, the sources cast an important light on the nature of one of the most widespread and popular forms of public musical entertainment of the period, and about the entrepreneurial techniques that were employed to make it successful.