Structural compliance, misfit strain and stripe nanostructures in cuprate superconductors

Structural compliance is the ability of a crystal structure to accommodate variations in local atomic bond-lengths without incurring large strain energies. We show that the structural compliance of cuprates is relatively small, so that short, highly doped, Cu-O-Cu bonds in stripes are subject to a tensile misfit strain. We develop a model to describe the effect of misfit strain on charge ordering in the copper oxygen planes of oxide materials and illustrate some of the low energy stripe nanostructures that can result.Comment: 4 pages 5 figure

Failure Probabilities and Tough-Brittle Crossover of Heterogeneous Materials with Continuous Disorder

The failure probabilities or the strength distributions of heterogeneous 1D systems with continuous local strength distribution and local load sharing have been studied using a simple, exact, recursive method. The fracture behavior depends on the local bond-strength distribution, the system size, and the applied stress, and crossovers occur as system size or stress changes. In the brittle region, systems with continuous disorders have a failure probability of the modified-Gumbel form, similar to that for systems with percolation disorder. The modified-Gumbel form is of special significance in weak-stress situations. This new recursive method has also been generalized to calculate exactly the failure probabilities under various boundary conditions, thereby illustrating the important effect of surfaces in the fracture process.Comment: 9 pages, revtex, 7 figure

Sex-Specific Responses of Life Span and Fitness to Variation in Developmental Versus Adult Diets in Drosophila melanogaster

Nutritional variation across the lifetime can have significant and sex-specific impacts on fitness. Using Drosophila melanogaster, we measured these impacts by testing the effects on life span and reproductive success of high or low yeast content in developmental versus adult diets, separately for each sex. We tested two hypotheses: that dietary mismatches between development and adulthood are costly and that any such costs are sex-specific. Overall, the results revealed the rich and complex responses of each sex to dietary variation across the lifetime. Contrary to the first hypothesis, dietary mismatches between developmental and adult life stages were not universally costly. Where costs of nutritional variation across the life course did occur, they were sex-, context-, and trait-specific, consistent with hypothesis 2. We found effects of mismatches between developmental and adult diets on reproductive success in females but not males. Adult diet was the main determinant of survival, and life span was significantly longer on high yeast adult food, in comparison to low, in both sexes. Developing on a high yeast diet also benefited adult female life span and reproductive success, regardless of adult diet. In contrast, a high yeast developmental diet was only beneficial for male life span when it was followed by low yeast adult food. Adult diet affected mating frequency in opposing directions, with males having higher mating frequency on high and females on low, with no interaction with developmental diet for either sex. The results emphasize the importance of sex differences and of the directionality of dietary mismatches in the responses to nutritional variation

Internalised Space

 "Duxbury was invited to participate in the two-person exhibition, Internalised Space as part of 2007 Christchurch International Arts Festival to, ""consider aspects of internal and external phenomena and space"", (Press Release) through printmedia works. 'Tomorrow' builds on the history of predicting and recording the weather, initially through diaries and journals (before weather forecasting) and later through weather bulletins and reports. In this work Duxbury recontextualises these as a kind of poetry and adds to her oeuvre that references the annotations of the 19th century English artist John Constable. <br />Terms that relate to the weather share commonalities with expressions of mood and subjective feelings and Duxbury utilises these in this work, 'Through a combination of construction and poetry [that] invokes the rational side of the mind to let go' (Ric Spencer, The West Review, 08/04/06). Through a sequence of eight panels - relief and silkscreen prints - that allude to the passing of time and the changing of weather conditions from fair to foul, Duxbury 'uses well this nexus point of focussed light studies and casual notes on the weather to give the viewer's mind enough room never quite to solidify the sublime'. In this work Duxbury extends her research into the sky and its atmosphere as both internal and external forces in the way of artists such as the Australian Howard Taylor, as well as Roni Horn and Hamish Fulton.&quot

Exposed to the elements: representations of atmospheric phenomena and the construction of a cultural psyche

By referencing images and texts of selected nineteenth century artists and writers, I will elucidate the ways in which experiences and representations of atmospheric phenomena have permeated the English cultural psyche and become a significant element in the definition of Englishness. The inherent properties of printmaking, such as sameness and difference and repetition and reproduction will be investigated, properties that underpin our readings of atmospheric phenomena. The main emphases of this research are the elemental forces of the weather, the transitory effects of light and atmosphere and their influence on the psyche. I will employ a diversity of media to investigate the potential for Printmaking to enhance representations of atmospheric phenomena. This will include traditional printmaking techniques such as relief printing alongside more contemporary means of reproduction and replication such as digital imaging and photography. I will encompass a wide range of formal vocabularies from minimalism to text-based conceptualism in the production of the work. The key questions of this research project are: • What significant changes occurred in the culture of early nineteenth century England that inspired artists and writers to place such particular significance on the representation of atmospheric phenomena? • In what ways have atmospheric phenomena and daily experiences of the weather entered the English cultural psyche? • In what ways can print media be utilised to interpret nineteenth century images and texts and give them significance in contemporary art practice? The project will culminate in a body of print media based work and an exegesis that will contextualise the visual research

Double Moonbow 2

"This 7-panel, framed relief print with a single word silk-screened on each panel relates to one of the necessary conditions to produce the phenomenon of a moonbow. The top of each frame is painted with one of the colours of the rainbow. This produces subtle colour reflections on the wall. Rather than being obvious, a faint, subdued reflection is revealed on the wall above the work, and is not necessarily seen by each viewer.<br /><br />As part of Duxbury's ongoing explorations of representations of atmospheric phenomena, especially the more evanescent and ethereal aspects, and the perception and interaction of the viewer, Double Moonbow 2 investigates a seldom seen phenomenon, the moonbow, painted by artists such as JMW Turner, sometimes photographed but not represented in printmaking. Moonbows are the rarely-seen night rainbows, which require very particular atmospheric conditions to become visible. The intention was to represent this rare event through media that requires the viewer to sahre the experience of an elusive phenomenon. <br /><br />Double Moonbow 2 was acquired by the NGV from In a Different Light, Galerie Düsseldorf, Perth 06 and selected by the curator Kirsty Grant for Proof at the NGV, a national exhibition that represented ""the vibrancy and diversity of contemporary Australian printmaking"". In this exhibition it was shown alongside artists David Noonan, Aleks Danko and Mike Parr.<br /><br />This work was chosen for its innovative use of the print medium and its interactive intentions. 'The modest scale - demands close proximity and the use of text requires the viewer to move past each work in order to read it. While Duxbury has produced room- and wall-scaled installations, her extension of the printed image beyond the confines of the frame is, in this example, very subtle.. ..referred to as sublime work - all the ruthless research that goes into making a sublime moment.' (Grant, catalogue p3). Reviews: R Spencer, West Australian, 2006; D Hansen, The Age 22/12/06."<br /&gt

Self-Attracting Walk on Lattices

We have studied a model of self-attracting walk proposed by Sapozhnikov using Monte Carlo method. The mean square displacement $\sim t^{2\nu}$ and the mean number of visited sites $\sim t^{k}$ are calculated for one-, two- and three-dimensional lattice. In one dimension, the walk shows diffusive behaviour with $\nu=k=1/2$. However, in two and three dimension, we observed a non-universal behaviour, i.e., the exponent $\nu$ varies continuously with the strength of the attracting interaction.Comment: 6 pages, latex, 6 postscript figures, Submitted J.Phys.

Reply to the comment by Jacobs and Thorpe

Reply to a comment on "Infinite-Cluster geometry in central-force networks", PRL 78 (1997), 1480. A discussion about the order of the rigidity percolation transition.Comment: 1 page revTe

Strength Reduction in Electrical and Elastic Networks

Particular aspects of problems ranging from dielectric breakdown to metal insu- lator transition can be studied using electrical o elastic networks. We present an expression for the mean breakdown strength of such networks.First, we intro- duce a method to evaluate the redistribution of current due to the removal of a finite number of elements from a hyper-cubic network of conducatances.It is used to determine the reduction of breakdown strength due to a fracture of size $\kappa$.Numerical analysis is used to show that the analogous reduction due to random removal of elements from electrical and elastic networks follow a similar form.One possible application, namely the use of bone density as a diagnostic tools for osteorosporosis,is discussed.Comment: one compressed file includes: 9 PostScrpt figures and a text fil