4,156 research outputs found
The multiplicity of value in the front-end of projects: The case of London transportation infrastructure
There is growing interest in the ways that value is understood in the context of projects and within project-based settings. Recent studies emphasise the multiplicity of project value in various project settings as perceived by different project actors. Drawing on previous work on project value and project front-end, this study expands on the idea of multiplicity of project value in the early project definition phase. To this end, the study draws from empirical data on infrastructure projects provision, including semi-structured interviews with a set of highly experienced and senior level informants with extensive knowledge and familiarity of infrastructure project planning and front-end decision making. The study is bounded with a focus on London, UK as an example of a complex, highly established global city with a great reliance on its infrastructure and a well-established projects ecology. Through inductive qualitative data analysis the study explores the role of infrastructure projects as solutions to policy problems, the multiple and complex nature of value in project definition and identifies three value levels, which are instrumental for project definition: local value, sector value and user value. The multi-level value framework in the project front-end extends and complements early decision making in planning and setting up of infrastructure projects
Machine learning model for event-based prognostics in gas circulator condition monitoring
Gas circulator (GC) units are an important rotating asset used in the Advanced Gas-cooled Reactor (AGR) design, facilitating the flow of CO2 gas through the reactor core. The ongoing maintenance and examination of these machines is important for operators in order to maintain safe and economic generation. GCs experience a dynamic duty cycle with periods of non-steady state behavior at regular refuelling intervals, posing a unique analysis problem for reliability engineers. In line with the increased data volumes and sophistication of available the technologies, the investigation of predictive and prognostic measurements has become a central interest in rotating asset condition monitoring. However, many of the state-of-the-art approaches finding success deal with the extrapolation of stationary time series feeds, with little to no consideration of more-complex but expected events in the data. In this paper we demonstrate a novel modelling approach for examining refuelling behaviors in GCs, with a focus on estimating their health state from vibration data. A machine learning model was constructed using the operational history of a unit experiencing an eventual inspection-based failure. This new approach to examining GC condition is shown to correspond well with explicit remaining useful life (RUL) measurements of the case study, improving on the existing rudimentary extrapolation methods often employed in rotating machinery health monitoring
Exploiting formyl peptide receptor 2 to promote microglial resolution: a new approach to Alzheimer's disease treatment.
Alzheimer’s disease and dementia are among the most significant current healthcare challenges given the rapidly growing elderly population, and the almost total lack of effective therapeutic interventions. Alzheimer’s disease pathology has long been considered in terms of accumulation of amyloid beta and hyperphosphorylated tau, but the importance of neuroinflammation in driving disease has taken greater precedence over the last 15–20 years. Inflammatory activation of the primary brain immune cells, the microglia, has been implicated in Alzheimer’s pathogenesis through genetic, preclinical, imaging and postmortem human studies, and strategies to regulate microglial activity may hold great promise for disease modification. Neuroinflammation is necessary for defence of the brain against pathogen invasion or damage but is normally self-limiting due to the engagement of endogenous pro-resolving circuitry that terminates inflammatory activity, a process that appears to fail in Alzheimer’s disease. Here, we discuss the potential for a major regulator and promoter of resolution, the receptor FPR2, to restrain pro-inflammatory microglial activity, and propose that it may serve as a valuable target for therapeutic investigation in Alzheimer’s disease
Aquatic Insects of Upper Three Runs Creek, Savannah River Plant, South Carolina. Part IV: Caddisflies (Trichoptera) of the Lower Reaches
Ninety-three species of caddisflies, representing 14 families, were identified from collections obtained from two localities on Upper Three Runs Creek, Savannah River Site, Aiken County, South Carolina. Collections of adult caddisflies were made biweekly over a 1-yr period with ultraviolet light traps. The similarity index, Jaccard\u27s Coefficient of Communities, showed that the two sites were over 78% similar with 73 species in common. Three species, Oxyethira setosa Denning, Triaenodes smithi Ross, and Nyctiophylax serratus Lago & Harris, are new distributional records for South Carolina. Two species of Triaenodes are new to science. Other species, which were considered to be endemic to the Upper Three Runs Creek drainage, rare outside of the drainage, or of limited distribution, included Cheumatopsyche richardsoni Gordon, Oxyethira dunbartonensis Kelley, Protoptila morettii Morse, Hydrophysche elissoma Ross, Triaenodes ochraceus (Betten and Mosely), Neotrichia falca Ross, Oecetis morsei Bueno-Soria, and Pycnopsyche virginica (Banks)
Geochemical constraints on the origin of enigmatic cemented chalks, Norfolk, UK
Very hard cemented chalk stacks and crusts found locally in the upper part of the Cretaceous Chalk of north Norfolk, UK, are related to solution features. The solution features, mainly pipes and caves, formed after deposition of the overlying Middle Pleistocene Wroxham Crag, probably by routing of sub-glacial, or glacial, melt-waters derived from late Pleistocene glaciers. New geochemical (particularly stable isotope) data shows that cementation of the chalks, although related spatially to the solution features, was not caused by glacier-derived waters. The carbon isotope composition of the chalk cements is typically around -9.5‰, indicative of biologically active soils. Moreover, the oxygen isotope compositions of the cements, around -5‰, are incompatible with water d18O values much below -9 to -10‰ (which probably precludes isotopically negative glacier-derived water), as resulting palaeo-temperatures are below zero. Taken together, the isotope data suggest chalk cementation occurred under interglacial conditions similar to the present. Dissolved calcium carbonate for cementation came from dissolution of reworked chalk in overlying MIS 12 glacial tills
Variation in syn-subduction sedimentation patterns from inner to outer portions of deep-water fold and thrust belts: examples from the Hikurangi subduction margin of New Zealand
The structure and distribution of accommodation in fold and thrust belts vary both laterally and longitudinally. Here we integrate gravity, bathymetry and 2D seismic datasets to investigate the structural and stratigraphic variation in the southern part of the Hikurangi subduction wedge, onshore and offshore North Island, New Zealand. Three morphostructural portions are recognized:
The inner portion demonstrates reactivation of inherited structures, producing thick-skinned deformation. Pre-subduction rocks are represented by kilometres of acoustically chaotic seismofacies. Thick-skinned deformation and readily deformable substrate lead to the development of wide trench-slope sub-basins, infilled with >5 km of syn-subduction sediments.
The mid portion typically demonstrates thrust faults with connections to deeper structures, leading to the development of an imbricate system with asymmetrical sub-basins typically <5 km thick developed on the back-limb of thrust related folds.
An antiformal stack marks the transition from the thick-skinned interior of the basin to the thin-skinned accretionary prism. Beyond this, the relatively non-deformed outer portion demonstrates frontal folds, propagating thrusts and up to 3 km thickness of syn-subduction strata.
Structural variation across the subduction wedge controls the generation of accommodation with implications for sediment distribution within fold and thrust belts and for petroleum system development
Human Research Ethics Committee Experiences and Views About Children's Participation in Research: Results From the MESSI Study.
As part of a larger study, Australian Human Research Ethics Committee (HREC) members and managers were surveyed about their decision-making and views about social research studies with child participants. Responses of 229 HREC members and 42 HREC managers are reported. While most HREC members had received ethical training, HREC training and guidelines specific to research involving children were rare. Most applications involving children had to go through a full ethical review, but few adverse events were reported to HRECs regarding the conduct of the studies. Revisions to study proposals requested by HRECs were mostly related to consent processes and age-appropriate language. One-third of HREC members said that they would approve research on any topic. Most were also concerned that the methodology was appropriate, and the risks and benefits were clearly articulated. Specific training and guidance are needed to increase HREC members' confidence to judge ethical research with children
Ectoplasm & Superspace Integration Measure for 2D Supergravity with Four Spinorial Supercurrents
Building on a previous derivation of the local chiral projector for a two
dimensional superspace with eight real supercharges, we provide the complete
density projection formula required for locally supersymmetrical theories in
this context. The derivation of this result is shown to be very efficient using
techniques based on the Ectoplasmic construction of local measures in
superspace.Comment: 18 pages, LaTeX; V2: minor changes, typos corrected, references
added; V3: version to appear in J. Phys. A: Math. Theor., some comments and
references added to address a referee reques
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A New Calibration Of Galactic Cepheid Period-Luminosity Relations From B To K Bands, And A Comparison To LMC Relations
Context. The universality of the Cepheid period-luminosity (PL) relations has been under discussion since metallicity effects were assumed to play a role in the value of the intercept and, more recently, of the slope of these relations. Aims. The goal of the present study is to calibrate the Galactic PL relations in various photometric bands (from B to K) and to compare the results to the well-established PL relations in the LMC. Methods. We use a set of 59 calibrating stars, the distances of which are measured using five different distance indicators: Hubble Space Telescope and revised Hipparcos parallaxes, infrared surface brightness and interferometric Baade-Wesselink parallaxes, and classical Zero-Age-Main-Sequence-fitting parallaxes for Cepheids belonging to open clusters or OB stars associations. A detailed discussion of absorption corrections and projection factor to be used is given. Results. We find no significant difference in the slopes of the PL relations between LMC and our Galaxy. Conclusions. We conclude that the Cepheid PL relations have universal slopes in all photometric bands, not depending on the galaxy under study (at least for LMC and Milky Way). The possible zero-point variation with metal content is not discussed in the present work, but an upper limit of 18.50 for the LMC distance modulus can be deduced from our data.McDonald Observator
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