10,881 research outputs found

    Determination of tungsten resonance absorption integrals by activation

    Get PDF
    Determination of tungsten resonance absorption integrals by activatio

    Examining the importance of Aberdeenshire (UK) coastal waters for North Sea bottlenose dolphins (Tursiops truncates)

    Get PDF
    Using land- and vessel-based surveys, data on the relative abundance, distribution and habitat use of bottlenose dolphins (Tursiops truncatus) in Aberdeenshire waters were collected between 1999 and 2001. Bottlenose dolphins were present throughout the year, with peak abundance during the months of March to May. The occurrence of calves was seasonal, With the proportion of calves highest during the spring months. Foraging behaviour was recorded mainly in the vicinity of Aberdeen harbour. Dolphins photographed in Aberdeenshire waters were successfully matched and confirmed as Moray Firth animals. The results of the present study suggest that Moray Firth bottlenose dolphins utilize Aberdeenshire waters more frequently than previously reported. Aberdeen harbour is apparently an important feeding area, and Aberdeenshire waters are regularly used by another-calf pairs. This has important management implications since this area of coastline does not currently form part of the designated Special Area of Conservation (SAC) for this population

    Conceptual modelling: Towards detecting modelling errors in engineering applications

    Get PDF
    Rapid advancements of modern technologies put high demands on mathematical modelling of engineering systems. Typically, systems are no longer “simple” objects, but rather coupled systems involving multiphysics phenomena, the modelling of which involves coupling of models that describe different phenomena. After constructing a mathematical model, it is essential to analyse the correctness of the coupled models and to detect modelling errors compromising the final modelling result. Broadly, there are two classes of modelling errors: (a) errors related to abstract modelling, eg, conceptual errors concerning the coherence of a model as a whole and (b) errors related to concrete modelling or instance modelling, eg, questions of approximation quality and implementation. Instance modelling errors, on the one hand, are relatively well understood. Abstract modelling errors, on the other, are not appropriately addressed by modern modelling methodologies. The aim of this paper is to initiate a discussion on abstract approaches and their usability for mathematical modelling of engineering systems with the goal of making it possible to catch conceptual modelling errors early and automatically by computer assistant tools. To that end, we argue that it is necessary to identify and employ suitable mathematical abstractions to capture an accurate conceptual description of the process of modelling engineering systems

    The importance of clean dwellings

    Get PDF
    n/

    The Baryon Fractions and Mass-to-Light Ratios of Early-Type Galaxies

    Full text link
    We jointly model 22 early-type gravitational lens galaxies with stellar dynamical measurements using standard CDM halo models. The sample is inhomogeneous in both its mass distributions and the evolution of its stellar populations unless the true uncertainties are significantly larger than the reported measurement errors. In general, the individual systems cannot constrain halo models, in the sense that the data poorly constrains the stellar mass fraction of the halo. The ensemble of systems, however, strongly constrains the average stellar mass represented by the visible galaxies to 0.026±0.0060.026\pm0.006 of the halo mass if we neglect adiabatic compression, rising to 0.056±0.0110.056\pm0.011 of the halo mass if we include adiabatic compression. Both estimates are significantly smaller than the global baryon fraction, corresponding to a star formation efficiency for early-type galaxies of 1010%-30%. In the adiabatically compressed models, we find an average local B-band stellar mass-to-light ratio of (M/L)_0 = (7.2\pm0.5)(M_{\sun}/L_{\sun}) that evolves by dlog(M/L)/dz=0.72±0.08d\log(M/L)/dz = -0.72\pm0.08 per unit redshift. Adjusting the isotropy of the stellar orbits has little effect on the results. The adiabatically compressed models are strongly favored if we impose either local estimates of the mass-to-light ratios of early-type galaxies or the weak lensing measurements for the lens galaxies on 100 kpc scales as model constraints.Comment: 9 figure

    Novel algorithms for 3D surface point cloud boundary detection and edge reconstruction

    Get PDF
    Tessellated surfaces generated from point clouds typically show inaccurate and jagged boundaries. This can lead to tolerance errors and problems such as machine judder if the model is used for ongoing manufacturing applications. This paper introduces a novel boundary point detection algorithm and spatial FFT-based filtering approach, which together allow for direct generation of low noise tessellated surfaces from point cloud data, which are not based on pre-defined threshold values. Existing detection techniques are optimized to detect points belonging to sharp edges and creases. The new algorithm is targeted at the detection of boundary points and it is able to do this better than the existing methods. The FFT-based edge reconstruction eliminates the problem of defining a specific polynomial function order for optimum polynomial curve fitting. The algorithms were tested to analyse the results and measure the execution time for point clouds generated from laser scanned measurements on a turbofan engine turbine blade with varying numbers of member points. The reconstructed edges fit the boundary points with an improvement factor of 4.7 over a standard polynomial fitting approach. Furthermore, through adding artificial noise it has been demonstrated that the detection algorithm is very robust for out-of-plane noise lower than 25% of the cloud resolution and it can produce satisfactory results when the noise is lower than 75%

    Spin Current and Shot Noise in Single-Molecule Quantum Dots with a Phonon Mode

    Full text link
    In this paper we investigate the spin-current and its shot-noise spectrum in a single-molecule quantum dot coupled with a local phonon mode. We pay special attention on the effect of phonon on the quantum transport property. The spin-polarization dependent current is generated by a rotating magnetic filed applied in the quantum dot. Our results show the remarkable influence of phonon mode on the zero-frequency shot noise. The electron-phonon interaction leads to sideband peaks which are located exactly on the integer number of the phonon frequency and moreover the peak-height is sensitive to the electron-phonon coupling.Comment: 17 pages,5 figure

    Barriers and facilitators to healthy eating for nurses in the workplace: an integrative review

    Full text link
    © 2016 John Wiley & Sons Ltd Aim: The aim was to conduct an integrative systematic review to identify barriers and facilitators to healthy eating for working nurses. Background: There is growing recognition of the influence of the workplace environment on the eating habits of the workforce, which in turn may contribute to increased overweight and obesity. Overweight and obesity exact enormous costs in terms of reduced well-being, worker productivity and increased risk of non-communicable diseases. The workplace is an ideal place to intervene and support healthy behaviours. This review aimed to identify barriers and facilitators to nurses’ healthy eating in the workplace. Design: Integrative mixed method review. Data sources: Five electronic databases were searched: CINAHL, MEDLINE, PROQUEST Health and Medicine, ScienceDirect and PsycINFO. Reference lists were searched. Included papers were published in English between 2000–2016. Of 26 included papers, 21 were qualitative and five quantitative. Review methods: An integrative literature review was undertaken. Quality appraisal of included studies used standardized checklists. A social-ecological framework was used to examine workplace facilitators and constraints to healthy eating, derived from the literature. Emergent themes were identified by thematic analysis. Results: Review participants were Registered, Enrolled and/or Nurse Assistants primarily working in hospitals in middle or high income countries. The majority of studies reported barriers to healthy eating related to adverse work schedules, individual barriers, aspects of the physical workplace environment and social eating practices at work. Few facilitators were reported. Overall, studies found the workplace exerts a considerable negative influence on nurses’ dietary intake. Conclusion: Reorientation of the workplace to promote healthy eating among nurses is required

    Improperly-zoned, spatially-marginalized, andpoorly-served? An analysis of mobile home parks in Los Angeles County

    Get PDF
    More than 6% of Americans live in mobile homes, and yet there has been limited scholarly attention to mobile home location or quality of life compared to conditions in other housing types. There has not been a single comprehensive study to date that assesses where mobile home parks (MHPs) are located within metropolitan areas, that explores why some neighborhoods have a greater concentration of MHPs than others, or examines what environmental or basic service conditions are like in those neighborhoods. In California, more than 1 million residents live in mobile homes, with the vast majority (75%) of these living in MHPs rather than standalone units. We answer two questions in this study. First, are MHPs in “worse” neighborhoods in terms of socioeconomic status, zoning, local land uses, accessibility to jobs, and environmental quality? Second, which neighborhood factors are most strongly correlated with MHP locations and concentrations? We answer these questions using data for all mobile home parks in Los Angeles County, California. We find that MHPs are more likely to be located in lower density neighborhoods and at the urban fringe. More than 41% of MHPs are in areas zoned for commercial or industrial purposes rather than residential uses. Not surprisingly then, we find that MHPs are located in areas with more environmental hazards. A multivariate analysis of neighborhood factors confirms our hypotheses. Moreover, we find that MHPs’ access to public services is worse than the average neighborhood in the county. We recommend that policymakers engage in targeted efforts to address disparities in service access and mitigate environmental hazards
    corecore