488 research outputs found

    Temporal and spatial patterning of sea surface temperature in the northern Benguela upwelling system: Possible environmental indicators of clupeoid production

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    The physical dynamics of the northern Benguela upwelling system between July 1981 and August 1987 were investigated by applying standardized Principal Components Analysis to a time-series of 235 mean, weekly sea surface temperature satellite images of the region. The first three principal components accounted for 87% of the total variance in the standardized input images and were the only components retained for interpretation. Principal Component I (PC I) represents the mean spatial structure of the system in terms of relative SST gradients, PC II represents the balance in dominance between inshore-offshore v. longshore SST gradients and PC III highlights patterns associated with the warming of the central Namibian region (19–23°S) in conjunction with the maintenance of cooler conditions to the north and/or south. These results are interpreted within the context of previous findings on the behaviour of the system, and their relevance toclupeoid recruitment is discussed. Strong negative loadings on PC II indicated conditions which would promote the longshore “retention” of clupeoid eggs and larvae and “concentration” of planktonic food acrossthermoclines and thermal fronts, whereas strong positive loadings on PC III indicated conditions which would promote onshore retention and concentration. Conditions promoting onshore retention would, onoccasion, have also been reflected by positive loadings on PC II whenever there was a uniform contraction of the offshore upwelling front, as a result of reduced, but similar, levels of upwelling along the entire coast

    Uncertainty in the availability of natural resources: Fossil fuels, critical metals and biomass

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    Energy policies are strongly influenced by resource availability and recoverability estimates. Yet these estimates are often highly uncertain, frequently incommensurable, and regularly contested. This paper explores how the uncertainties surrounding estimates of the availability of fossil fuels, biomass and critical metals are conceptualised and communicated. The contention is that a better understanding of the uncertainties surrounding resource estimates for both conventional and renewable energy resources can contribute to more effective policy decision making in the long term. Two complementary approaches for framing uncertainty are considered in detail: a descriptive typology of uncertainties and a framework that conceptualises uncertainty as alternative states of incomplete knowledge. Both have the potential to be useful analytical and communication tools. For the three resource types considered here we find that data limitations, inconsistent definitions and the use of incommensurable methodologies present a pervasive problem that impedes comparison. Many aspects of resource uncertainty are also not commonly captured in the conventional resource classification schemes. This highlights the need for considerable care when developing and comparing aggregate resource estimates and when using these to inform strategic energy policy decisions

    Content and discontent: a qualitative exploration of obstacles to elearning engagement in medical students

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    BACKGROUND: Elearning is ubiquitous in healthcare professions education. Its equivalence to ‘traditional’ educational delivery methods is well established. There is a research imperative to clarify when and how to use elearning most effectively to mitigate the potential of it becoming merely a ‘disruptive technology.’ Research has begun to broadly identify challenges encountered by elearning users. In this study, we explore in depth the perceived obstacles to elearning engagement amongst medical students. Sensitising concepts of achievement emotions and the cognitive demands of multi-tasking highlight why students’ deeply emotional responses to elearning may be so important in their learning. METHODS: This study used focus groups as a data collection tool. A purposeful sample of 31 participated. Iterative data gathering and analysis phases employed a constant comparative approach to generate themes firmly grounded in participant experience. RESULTS: Key themes that emerged from the data included a sense of injustice, passivity and a feeling of being ‘lost at sea’. The actual content of the elearning resource provided important context. CONCLUSIONS: The identified themes have strong emotional foundations. These responses, interpreted through the lens of achievement emotions, have not previously been described. Appreciation of their importance is of benefit to educators involved in curriculum development or delivery. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12909-016-0710-5) contains supplementary material, which is available to authorized users

    Slow equivariant lump dynamics on the two sphere

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    The low-energy, rotationally equivariant dynamics of n CP^1 lumps on S^2 is studied within the approximation of geodesic motion in the moduli space of static solutions. The volume and curvature properties of this moduli space are computed. By lifting the geodesic flow to the completion of an n-fold cover of the moduli space, a good understanding of nearly singular lump dynamics within this approximation is obtained.Comment: 12 pages, 3 figure

    Making in landscape. Time, geometry, observation and transitory objects. From methods of inquiry to instruments for design.

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    This project is concerned with using the introduction of geometric structures into landscape to explore the interaction between natural ephemera, geometry and the observer. It has implications for sculpture, architecture and landscape. This Masters by project, also traces the background ideas and work that led to the particular approach to these elements

    The epiphenominal in architecture and a creative sequence

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    This PhD by dissertation and project is an exploration of whether the epiphenomena that occurs when the ephemera of nature and the building align can be the basis for architectural design. This can produce transient events that enhance our secular being. Also another premise of this PhD is whether, as a fine artist, my aesthetic propensities can be modulated onto architectural practice

    Magnetic bubble refraction and quasibreathers in inhomogeneous antiferromagnets

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    The dynamics of magnetic bubble solitons in a two-dimensional isotropic antiferromagnetic spin lattice is studied, in the case where the exchange integral J(x,y) is position dependent. In the near continuum regime, this system is described by the relativistic O(3) sigma model on a spacetime with a spatially inhomogeneous metric, determined by J. The geodesic approximation is used to describe low energy soliton dynamics in this system: n-soliton motion is approximated by geodesic motion in the moduli space of static n-solitons, equipped with the L^2 metric. Explicit formulae for this metric for various natural choices of J(x,y) are obtained. From these it is shown that single soliton trajectories experience refraction, with 1/J analogous to the refractive index, and that this refraction effect allows the construction of simple bubble lenses and bubble guides. The case where J has a disk inhomogeneity (taking the value J_1 outside a disk, and J_2<J_1 inside) is considered in detail. It is argued that, for sufficiently large J_1/J_2 this type of antiferromagnet supports approximate quasibreathers: two or more coincident bubbles confined within the disk which spin internally while their shape undergoes periodic oscillations with a generically incommensurate period.Comment: Conference proceedings paper for talk given at Nonlinear Physics Theory and Experiment IV, Gallipoli, Italy, June 200

    Farmer Led Regenerative Agriculture for Africa

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    Divestment prevails over the green paradox when anticipating strong future climate policies

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    Fossil fuel market dynamics will have a significant impact on the effectiveness of climate policies1. Both fossil fuel owners and investors in fossil fuel infrastructure are sensitive to climate policies that threaten their natural resource endowments and production capacities2,3,4, which will consequently affect their near-term behaviour. Although weak in near-term policy commitments5,6, the Paris Agreement on climate7 signalled strong ambitions in climate change stabilization. Many studies emphasize that the 2 °C target can still be achieved even if strong climate policies are delayed until 20308,9,10. However, sudden implementation will have severe consequences for fossil fuel markets and beyond and these studies ignore the anticipation effects of owners and investors. Here we use two energy–economy models to study the collective influence of the two central but opposing anticipation arguments, the green paradox11 and the divestment effect12, which have, to date, been discussed only separately. For a wide range of future climate policies, we find that anticipation effects, on balance, reduce CO2 emissions during the implementation lag. This is because of strong divestment in coal power plants starting ten years ahead of policy implementation. The green paradox effect is identified, but is small under reasonable assumptions

    The potential of low-cost 3D imaging technologies for forestry applications: Setting a research agenda for low-cost remote sensing inventory tasks

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    Limitations with benchmark light detection and ranging (LiDAR) technologies in forestry have prompted the exploration of handheld or wearable low-cost 3D sensors (<2000 USD). These sensors are now being integrated into consumer devices, such as the Apple iPad Pro 2020. This study was aimed at determining future research recommendations to promote the adoption of terrestrial low-cost technologies within forest measurement tasks. We reviewed the current literature surrounding the application of low-cost 3D remote sensing (RS) technologies. We also surveyed forestry professionals to determine what inventory metrics were considered important and/or difficult to capture using conventional methods. The current research focus regarding inventory metrics captured by low-cost sensors aligns with the metrics identified as important by survey respondents. Based on the literature review and survey, a suite of research directions are proposed to democratise the access to and development of low-cost 3D for forestry: (1) the development of methods for integrating standalone colour and depth (RGB-D) sensors into handheld or wearable devices; (2) the development of a sensor-agnostic method for determining the optimal capture procedures with low-cost RS technologies in forestry settings; (3) the development of simultaneous localisation and mapping (SLAM) algorithms designed for forestry environments; and (4) the exploration of plot-scale forestry captures that utilise low-cost devices at both terrestrial and airborne scales
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