Heterotopia in Networked Learning: Beyond the Shadow Side of Participation in Learning Communities

As it has evolved, networked learning (NL) has come to emphasise the importance of the collaborative learning aspects and possibilities of online learning. The importance assumed for 'collaboration based' forms of participation within NL has almost become ubiquitous and is frequently seen as an unquestionable good aspect - a utopian view of participation which does not acknowledge the 'shadow side' of participation in learning. In the paper we examine some of the darker sides of collaborative participation which in its extreme manifestations can be experienced as normative and, we suggest, a form of tyranny of the dominant and which instead of having a liberating effect, reinforces a form of oppression and control. We argue this is most likely to be the case in the absence of reflexivity and understanding of different ways and approaches to participation. We go on to suggest an alternative and potentially more productive perspective which, after Foucault, is a heterotopian one. A perspective that acknowledges and assumes disruption and which disturbs our customary notion of ourselves. Participation in heterotopian spaces is disturbing and ambiguous, but it offers a space in which to imagine, to desire and act differently

Evidence of late Quaternary environmental change in a continental east Antarctic lake from lacustrine sedimentary pigment distributions

A sediment core from Progress Lake, one of the oldest lacustrine sequences in East Antarctica, contains distinct zones dating from a previous interglacial (most likely Marine Isotope Stage 5e, c. 125-115 kyr BP) and the present interglacial (Marine Isotope Stage 1), separated by a transition zone representing when the lake became sub-glacial. Profiles of fossil pigments, determined using high performance liquid chromatography and liquid chromatography-tandem mass spectrometry, show distinct differences in the photoautotrophic community during these two interglacial periods. The first was dominated by algae and purple phototrophic bacteria, with periods of photic zone euxinia indicated by pigments from anoxygenic phototrophic bacteria. Specific chlorophyll a derivatives reveal periods when grazing pressure impacted significantly on the phytoplankton community. The virtual absence of pigments in the transition zone reflects severe restriction of photoautotrophic activity, consistent with the take having become sub-glacial. Retreat of snow and ice in the late Holocene (3345 C-14 yr Bp) allowed establishment of a less diverse primary producer community, restricted to algae and cyanobacteria. Grazers were severely restricted and oxidative transformation was more important than during the previous interglacial. The pigment data provide a unique and detailed insight in to the evolution of the lake ecology over an interglacial-glacial-interglacial transition and strong evidence that the Marine Isotope Stage 5e interglacial in this region of coastal East Antarctica was several degrees warmer than at present

Electron localisation in static and time-dependent one-dimensional model systems

Electron localization is the tendency of an electron in a many-body system to exclude other electrons from its vicinity. Using a new natural measure of localization based on the exact manyelectron wavefunction, we find that localization can vary considerably between different ground-state systems, and can also be strongly disrupted, as a function of time, when a system is driven by an applied electric field. We use our new measure to assess the well-known electron localization function (ELF), both in its approximate single-particle form (often applied within density-functional theory) and its full many-particle form. The full ELF always gives an excellent description of localization, but the approximate ELF fails in time-dependent situations, even when the exact Kohn-Sham orbitals are employed.Comment: 7 pages, 4 figure

The speed of range shifts in fragmented landscapes

Peer reviewedPublisher PD

Veering triangulations admit strict angle structures

Agol recently introduced the concept of a veering taut triangulation, which is a taut triangulation with some extra combinatorial structure. We define the weaker notion of a "veering triangulation" and use it to show that all veering triangulations admit strict angle structures. We also answer a question of Agol, giving an example of a veering taut triangulation that is not layered.Comment: 15 pages, 9 figure

Large NcN_c QCD at non-zero chemical potential

The general issue of large $N_c$ QCD at nonzero chemical potential is considered with a focus on understanding the difference between large $N_c$ QCD with an isospin chemical potential and large $N_c$ QCD with a baryon chemical potential. A simple diagrammatic analysis analogous to `t Hooft's analysis at $\mu=0$ implies that the free energy with a given baryon chemical potential is equal to the free energy with an isospin chemical potential of the same value plus $1/N_c$ corrections. Phenomenologically, these two systems behave quite differently. A scenario to explain this difference in light of the diagrammatic analysis is explored. This scenario is based on a phase transition associated with pion condensation when the isospin chemical potential exceeds $m_\pi/2$; associated with this transition there is breakdown of the $1/N_c$ expansion--in the pion condensed phase there is a distinct $1/N_c$ expansion including a larger set of diagrams. While this scenario is natural, there are a number of theoretical issues which at least superficially challenge it. Most of these can be accommodated. However, the behavior of quenched QCD which raises a number of apparently analogous issues cannot be easily understood completely in terms of an analogous scenario. Thus, the overall issue remains open

Effect of Aging in Tillers of \u3ci\u3ePanicum maximum\u3c/i\u3e on Leaf Elongation Rate

Two cultivars of Guinea grass (P. maximum, Jacq.), Mombaça and Tanzânia, were cultivated in five litre pots, as single plants, in a green house. Plants were subjected to three defoliation levels (100, 200 and 400 mm height) for five successive monthly harvests. The experimental design was a 3x2 randomised block with five replicates. Three types of tiller (main, primary and secondary) were selected, at random, on each plant and leaf elongation rate (LER) above cutting height was measured, weekly, between harvests. There were significant differences (P \u3c 0.05) in LER between tiller types in cv. Mombaça in all periods, but only in period two in cv. Tanzânia. In the last period tillers were classified, at random, as old (over four months age) mature (between two and four months) and young (between one and two months). Old tillers had a lower (P \u3c 0.05) LER than the other two categories in both cultivars and lower (P \u3c 0.05) SLA (specific leaf area) in Mombaça