Critical O(d)O(d)-equivariant biharmonic maps

We study $O(d)$-equivariant biharmonic maps in the critical dimension. A major consequence of our study concerns the corresponding heat flow. More precisely, we prove that blowup occurs in the biharmonic map heat flow from $B^4(0, 1)$ into $S^4$. To our knowledge, this was the first example of blowup for the biharmonic map heat flow. Such results have been hard to prove, due to the inapplicability of the maximum principle in the biharmonic case. Furthermore, we classify the possible $O(4)$-equivariant biharmonic maps from $\mathbf{R}^4$ into $S^4$, and we show that there exists, in contrast to the harmonic map analogue, equivariant biharmonic maps from $B^4(0,1)$ into $S^4$ that wind around $S^4$ as many times as we wish. We believe that the ideas developed herein could be useful in the study of other higher-order parabolic equations.Comment: 24 pages, 1 figure. Published online in Calculus of Variations and Partial Differential Equations, 201

Sarah Turner - eco-artist and designer through craft-based upcycling

Sarah Turner is an eco-artist and designer who practices craft-based upcycling with waste plastic bottles and cans to create lighting, sculpture and decorative home interior products. Since 1998, her enthusiasm, creativity and good will have allowed her to gain several high-profile client commissions and to win awards from design, innovation and business competitions. The aim of this portrait is to introduce Sarah’s work and shed light on the resources, knowledge and skills involved in her practice and on the barriers to and drivers for her craft-based upcycling. We consider that Sarah’s work could be one of the stepping stones for a shift towards more sustainable craft practice, both in the United Kingdom and beyond. By exploring the right ingredients for craft-based upcycling, barriers liable to be faced and key drivers that stimulate motivation, we hope that this portrait will inspire and attract more designers and makers to embed upcycling in their future practice

Universal scaling and ferroelectric hysteresis regimes in the giant squid axon propagating action potential: a Phase Space Approach

The experimental data for the giant squid axon propagated action potential is examined in phase space. Plots of capacitive and ionic currents vs. potential exhibit linear portions providing temperature dependent time rates and maximum conductance constants for sodium and Potassium channels. First order phase transitions of ionic channels are identified. Incorporation of time rates into Avrami equations for fractions of open channels yields for each channel a temperature independent dimensionless constant that is close in value to the fine structure constant. It also reveals temperature independent scaling exponents. Evidence is presented that the action potential traverses a ferroelectric hysteresis loop. This results in a second order phase transition polarization flip at the peak of the action potential, followed by closing of sodium and opening of potassium channels, and finally closing the loop by reversing the polarization flip as the resting potential is reached. The existence of this hysteresis loop for the giant squid action potential suggests the possibility of neurons with two stable states, the basis for memory storage and retrieval.Comment: 19 pages, 6 figure

Observation of narrow-band noise accompanying the breakdown of insulating states in high Landau levels

Recent magnetotransport experiments on high mobility two-dimensional electron systems have revealed many-body electron states unique to high Landau levels. Among these are re-entrant integer quantum Hall states which undergo sharp transitions to conduction above some threshold field. Here we report that these transitions are often accompanied by narrow- and broad-band noise with frequencies which are strongly dependent on the magnitude of the applied dc current.Comment: 4 pages, 3 figure

Regional geochemical and geophysical surveys in the Berwyn Dome and adjacent areas, north Wales

This report describes stream sediment and gravity surveys carried out across the Berwyn Dome and adjacent areas. The gravity survey confirmed the presence of a broad regional Bouguer anomaly low in the central part of the Dome, on which is superimposed several smaller irregular highs and lows. Some of these local anomalies possibly reflect small igneous bodies but more detailed gravity surveys would be needed to determine their form. Near Corwen the Bryneglwys Fault coincides with a 4.5 mGa1 anomaly but southwards the two features diverge, suggesting that the density interface is related either to a splay fault or to the eastern margin of the Lower Palaeozoic Montgomery trough. Some other structural trends are weakly reflected on the Bouguer anomaly and aeromagnetic maps, but there is no clear correlation with known base metal mineralisation. The Bouguer anomalies cannot be attributed to particular structures with any certainty but are probably due to a number of factors, including variation in the Precambrian basement and changes in the lithology and thickness of Lower Palaeozoic sedimentary rocks. There is no evidence for a large granitic body in Lower Palaeozoic rocks underlying the mineralisation at Llangynog. The aeromagnetic map suggests the presence of a magnetic basement at a depth of 3-4 km centred beneath the northwestern margin of the Dome. The stream sediment survey involved the collection of a - 100 mesh stream sediment, panned concentrate and water sample from each of the 399 sites sampled. The sample density was 1 site per 1.5 km*. Cu, Pb, Zn, Ba, Fe, Mn, Co, V, Cr, Ni, Zr, MO and Sn were determined in the stream sediments, Cu, Pb, Zn, Ba, Fe, Mn, Ce, Sn, Sb, Ti, Ni and As in the panned concentrates and Cu, Pb and Zn in stream waters. Major variations in the results are related to (i) hydrous oxide precipitation processes, (ii) contamination from human activities, (iii) base metal and baryte mineralisation, (iv) monazite concentrations in panned concentrates, (v) hitherto unrecorded gold mineralisation and (vi) lithological variations. The latter were related principally to shale-sandstone variation, but groups of elements attributable to the presence of basic intrusions, phosphatic rocks, coal measures, sandstones, limestones and volcanics were also discerned. Threshold levels were established from cumulative frequency curve analysis, and some anomalous sites were examined in the field. Anomalies did not form prominent coherent groups and were generally weak and scattered, with a wide variety of element groupings reflecting a range of causes. Many anomalous panned concentrates were examined mineralogically to try to . determine whether anomalies were related to chemically extreme background lithologies, contamination, or mineralisation. All the anomalies were related to one or more of the major causes of variation, although because of the very limited amount of follow-up work carried out the precise cause of many anomalies remains uncertain. No anomaly is considered to represent a strong prospect but several deserve further limited investigation, notably those associated with (i) gold mineralisation in the northwest of the area, (ii) baryte, perhaps accompanied by base metal ’ mineralisation, associated with Caradocian volcanics and phosphatic rocks at several localities, (iii) mineralisation associated with Llandeilian limestones and volcanic rocks north of Llanrhaeadr, and (iv) copper mineralisation associated with intrusives near the eastern margin of the Dome, where survey data is most incomplete

Antenna and radome loss measurements for MFMR and PMIS with appendix on MFMR/PMIS computer programs

The NMSU/PSL radiometer antenna calibration facility is described, and the antenna and radome loss measurements made on the passive microwave imaging system and the multifrequency microwave radiometer are summarized. Antenna/radome data reduction techniques, estimation of sky brightness temperatures, and bucket performance tests are presented along with radiometer computer programs

Cultures within a culture: the role of nationality and religion for environmentally significant behaviour in students living in university accommodation

Reducing global warming cannot be achieved through technological interventions alone; it requires a change in human behaviour. Households are a major contributor to carbon emissions, and thus play an integral part in strategies aiming at a more sustainable living. Behaviour changes in the household can make a significant contribution towards reducing CO2 emissions. However, people vary strongly in their household practices; differences in behaviour account for a substantial amount of variance in heat, electricity, and water consumption (Gill et al., 2010). What causes these differences? In addition to age and education, nationality and religion play a role: They impact on physical aspects of well-being and on environmental attitudes (e.g., Isaacs et al., 2010; Guth et al., 1995). The physical aspect such as perception of warmth is of importance insofar as that comfort practices could influence on environmentally significant behaviour. The Eurobarometer 295 (2008), a study on the attitudes of European citizens towards the environment, also revealed differences in attitudes and behaviour of Europeans towards the environment. Therefore, steps to promote more sustainable living have to be adapted to different cultures. Rising globalization brings about more heterogeneous populations, meaning that there will be increasingly "cultures within a culture." An important question is what happens to cultural differences in environmentally significant behaviour in such a setting. It could be that differences are diluted by a largely shared environment, or that they continue to persist, thanks to being deeply rooted in one’s origin and to the non-shared part of the environment. Our study: The aim of this study was to examine the variation in pro-environmental attitudes, behaviour, and values in members of a community now living in a very similar setting but coming from diverse backgrounds. If personal background accounts for differences in the variables at stake, then this has important implications, e.g. for all national interventions launched to change behaviour. Data was collected through a web-based survey. The survey was sent out to first-year students living in university accommodation at the University of Greenwich. Religion, strength of religion, nationality, years living in the UK, program studied, gender and age were recorded and the impact of these variables on a variety of measures such as pro- environmental attitudes, values, and actual behaviour was assessed. Results are currently being analysed but preliminary data suggest that sub-culture does play a role and thus needs to be considered when developing carbon reduction interventions. The implications of these findings for the University and national policies are discussed

Coupled Ferromagnetic and Nematic Ordering of Fermions in an Optical Flux Lattice

Ultracold atoms in Raman-dressed optical lattices allow for effective momentum-dependent interactions among single-species fermions originating from short-range s-wave interactions. These dressed-state interactions combined with very flat bands encountered in the recently introduced optical flux lattices push the Stoner instability towards weaker repulsive interactions, making it accessible with current experiments. As a consequence of the coupling between spin and orbital degrees of freedom, the magnetic phase features Ising nematic order.Comment: 5 pages, 4 figures (published version