441 research outputs found
An in situ assessment of seabed stability in Baynes Sound, British Columbia, Canada
No full textSutherland, T.F. and Amos, C.L., 2020. An in situ assessment of seabed stability in Baynes Sound, British Columbia, Canada. Journal of Coastal Research, 36(3), 472-486. Coconut Creek (Florida), ISSN 0749-0208. The Sea Carousel, an annular flume, was deployed to examine (in situ) fundamental parameters of seabed stability in Baynes Sound, British Columbia, Canada. Sediment grain size, water and organic contents, and chlorophyll and phaeopigment concentrations were collected to establish a hierarchy of factors associated with seabed stability. Sediment stability increased toward the Sound entrance in concert with decreases in water, organic, and silt-clay contents and a transition from cohesive to noncohesive properties. Bed-stress estimates, based on the quadratic stress law and turbulent kinetic energy (TKE) methods, showed a decrease in the drag coefficient from the inner (0.04) to the outer (0.0015) Sound. Surface erosion thresholds ranged between 0.04 to 0.28 Pa, whereas the friction coefficients (e.g., the failure envelop) were on average 12°, representing normally consolidated sediments. Type I (floc) erosion occurred at low shear stresses, whereas type II (mass) erosion happened at higher values. Erosion rates (E, for type I erosion) fitted a power function of excess shear stress (E
m = τ0 - τcrit,z)m with zero offset, where 0.81 < m < 2.32. The lowest and highest values for a given excess-shear stress occurred in the inner Sound and outer Sound, respectively. Settling of (resuspended) sediment after an exponential decay law [d(SSC)/dt] = SSC0 (expkt), where k fell within that of published values (3 < k < 539). Higher values of k (fastest settling) were observed in the inner Sound relative to the outer Sound. The sedimentation diameter (ds) fell in a coarse-silt to fine-sand range and was larger in the outer Sound, reflecting a coarsening of bed sediments.
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Hydrodynamic controls on the particle size of resuspended sediment from sandy and muddy substrates in British Columbia, Canada
No full textA benthic annular flume, Sea Carousel, was deployed at both sand-dominated (Baynes Sound) and mud-dominated (Carrie Bay) stations in British Columbia, Canada, to examine the character of near-bed flow over these contrasting bottom types and its control on particle size of resuspended sediment. An assessment has also been made of the turbidity-induced drag reduction due to suspension of bottom sediments. The median sizes of suspended material from the sandy sites have been compared with the well-known Rouse theory, whereas the aggregates resuspended from muddy stations were scaled with the energy dissipation rate (ϵ) determined from high-frequency three-dimensional flow measures in the flume. There was no evidence in the turbulence spectra in the Sea Carousel of energy inputs in the paddle and lid rotational frequencies, and a f-5/3 slope for f > 2 Hz in turbulent transitional flows was evident. The bed roughness length of sandy sites was Reynolds-number dependent but was asymptotic to a constant value of 2 mm at high flows. This equated to a dimensionless drag coefficient at 1 m above bed of a constant, 3 × 10-3 (also at high Reynolds numbers), which agrees well with values reported in the literature. The median size of suspended sand (from the sandy sites) and equivalent still water settling rate (ws) scaled with the friction velocity (u*) in the form ws/u* = D*/8. The median size of resuspended aggregates (df) scaled inversely with dissipation (ϵ) in the form df = 5 × 10-6ϵ-0.24m, which is close to the relationship found in the literature.</p
Underemployment : a skills utilisation perspective
No full textMore than half of all employees believe that the skills they possess are higher than those required to do their present jobs. This is one of several findings reported in a research paper on "under-employment" in the current edition of the University of Strathclyde's Fraser of Allander Review published today. According to the author of the paper, John Sutherland of the Scottish Centre for Employment Research at the university, this provides further evidence that "under-employment" is as important a policy problem as "unemployment"
Seabed attributes and meiofaunal abundance associated with a hydrodynamic gradient in Baynes Sound, British Columbia, Canada
No full textSutherland, T.F.; Garcia-Hoyos, L.M.; Poon, P.; Krassovski, M.V.; Foreman, M.G.G.; Martin, A.J., and Amos, C.L., 2018. Seabed attributes and meiofaunal abundance associated with a hydrodynamic gradient in Baynes Sound, British Columbia, Canada. The distribution of seabed geotechnical, biochemical, and meiofauna attributes was examined in Baynes Sound, British Columbia, between 2009 and 2014. Among attributes measured were sediment porosity, organic carbon and nitrogen, and trace element concentrations (e.g., zinc, copper), which increased with increasing sediment fines content toward the head of the Sound. A ternary plot (sand-silt-clay percentages) revealed a constant clay/silt ratio across a range of sand proportions with textures ranging from well-sorted sand at the high-energy SE entrance to silt-dominated mud in the depositional basin. These sediment textures were related to modeled maximum velocity values within 5 m of the seabed (Umax,5), with highest values (restricted entrance) and lowest values (deep basin) representing sand depositional and mud depositional facies. Sediment porewater sulfide fell into an oxic category (0-700 μM), exhibiting a lack of variation and organic enrichment within the Sound. The first principal component analysis (PCA) factor described the alignment between fine sediments, organics, Cu and Zn, and meiofauna attributes and accounted for 49% of the total variance. The second PCA factor (19% of total variance) described the relationship between Umax,5 and sediment grain size fractions >0.5 mm and an indirect association with water depth and fine sand (0.105-0.250 mm). Meiofauna were associated with a medium sand fraction (0.25 mm) characterized by low-porosity and low-organic sand loam textures. Although the range in abundance was relatively greater for nematodes, harpacticoid copepods revealed a stronger response to changes in sediment geotechnical and organic attributes, suggesting these taxa may be used to describe seabed variations or potential perturbations.</p
PT deformation of Calogero-Sutherland models
No full textCalogero-Sutherland models of N identical particles on a circle are deformed away from hermiticity but retaining a PT symmetry. The interaction potential gets completely regularized, which adds to the energy spectrum an infinite tower of previously non-normalizable states. For integral values of the coupling, extra degeneracy occurs and a nonlinear conserved supersymmetry charge enlarges the ring of Liouville charges. The integrability structure is maintained. We discuss the AN −1-type models in general and work out details for the cases of A2 and G2. © 2019, The Author(s)
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The data-index: an author-level metric that values impactful data and incentivises data sharing
No full textAbstract Author-level metrics are a widely used measure of scientific success. The h-index, and its variants, measure publication output (number of publications) and impact (number of citations), and these are often used to allocate funding or jobs. Here we argue that the emphasis on publication output and impact hinders progress in the fields of ecology and evolution as it disincentivises two fundamental practices: generating long-term datasets and sharing data. We describe a new author-level metric, the data-index, which values dataset output and impact and promotes generating and sharing data as a result. It is designed to complement other metrics of scientific success, as scientific contributions are diverse and our value system should reflect that. Future work should focus on designing alternative metrics that value our wider merits, such as communicating our research, informing policy, mentoring other scientists, and providing open-access code and tools
Visualisation, imagery, and the development of geometrical reasoning
No full textThis report focuses on some aspects of the nature and role of visualisation and imagery in the teaching and learning of mathematics, particularly as a component in the development of geometrical reasoning. Issues briefly addressed include the relationship between imagery and perception, imagery and memory, the nature of dynamic images, and the interaction between imagery and concept development. The report concludes with a series of questions that may provide a suitable programme for research and lays the foundation for further work of the BSRLM geometry working group
Problems with competence assessment as it applies to student nurses
No full textNursing has enthusiastically embraced the concept of continuing competence as the key means of reassuring the public of the overall quality of the profession. There are many definitions of competence and a number of nursing regulatory bodies have put into operation, a definition which is reductionist rather then holistic in nature. Not surprisingly, and as a consequence many nurses, including nurse educators, think competence comprises a number of key competencies which can be isolated, accumulated and tallied. It is clear that both philosophically and practically these notions of competence have influenced the way that student nurses are currently educated. More specifically it is in preparation for their initial entry to practice that the approach to competence assessment of student nurses becomes problematic. In this paper it will be argued that the principles of continuing competence assessment, associated with the on going competence of experienced registered nurses, do not readily translate to students who are still in the process of learning. We suggest that solutions to this problem are three-fold and can be found by replicating for the student the conditions that apply to the assessment of continuing competence for registered nurses
Training and employee use of skills in Scotland : some evidence
No full textIncreasing labour productivity is considered to be the most important means by which the Scottish Government will achieve its principal economic objective of increasing sustainable economic growth (Scottish Government, 2007a, p.1); and the policy assumption is that labour productivity will increase, directly and indirectly, as a consequence of increasing workforce skills levels (Leitch Review of Skills, 2007: Scottish Government, 2007b, p6). However, increases in human capital investments, especially over the last two decades, have not been translated into improvements in labour productivity. As the Scottish Government (2007a) itself acknowledges: “… strong performance on skills and qualifications does not feed through effectively enough to productivity” (p14)
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