Further advances in orchid mycorrhizal research

Orchid mycorrhizas are mutualistic interactions between fungi and members of the Orchidaceae, the world’s largest plant family. The majority of the world’s orchids are photosynthetic, a small number of species are myco-heterotrophic throughout their lifetime, and recent research indicates a third mode (mixotrophy) whereby green orchids supplement their photosynthetically fixed carbon with carbon derived from their mycorrhizal fungus. Molecular identification studies of orchid-associated fungi indicate a wide range of fungi might be orchid mycobionts, show common fungal taxa across the globe and support the view that some orchids have specific fungal interactions. Confirmation of mycorrhizal status requires isolation of the fungi and restoration of functional mycorrhizas. New methods may now be used to store orchid-associated fungi and store and germinate seed, leading to more efficient culture of orchid species. However, many orchid mycorrhizas must be synthesised before conservation of these associations can be attempted in the field. Further gene expression studies of orchid mycorrhizas are needed to better understand the establishment and maintenance of the interaction. These data will add to efforts to conserve this diverse and valuable association

Resistive switching in nanogap systems on SiO2 substrates

Voltage-controlled resistive switching is demonstrated in various gap systems on SiO2 substrate. The nanosized gaps are made by different means using different materials including metal, semiconductor, and metallic nonmetal. The switching site is further reduced by using multi-walled carbon nanotubes and single-walled carbon nanotubes. The switching in all the gap systems shares the same characteristics. This independence of switching on the material compositions of the electrodes, accompanied by observable damage to the SiO2 substrate at the gap region, bespeaks the intrinsic switching from post-breakdown SiO2. It calls for caution when studying resistive switching in nanosystems on oxide substrates, since oxide breakdown extrinsic to the nanosystem can mimic resistive switching. Meanwhile, the high ON/OFF ratio (10E5), fast switching time (2 us, test limit), durable cycles demonstrated show promising memory properties. The intermediate states observed reveal the filamentary conduction nature.Comment: 7 pages, 7 figure

Wadawurrung ethnobotany as synthesised from the research of Louis Lane

This research looks at how plants were used by Wadawurrung People prior to colonisation in a region classified as a biodiverse hotspot. This thesis provides a unique and valuable opportunity for modern society to learn about the Wadawurrung People’s comprehensive relationship with plants and their way of life

Stabilizing the forming process in unipolar resistance switching using an improved compliance current limiter

The high reset current IR in unipolar resistance switching now poses major obstacles to practical applications in memory devices. In particular, the first IR-value after the forming process is so high that the capacitors sometimes do not exhibit reliable unipolar resistance switching. We found that the compliance current Icomp is a critical parameter for reducing IR-values. We therefore introduced an improved, simple, easy to use Icomp-limiter that stabilizes the forming process by drastically decreasing current overflow, in order to precisely control the Icomp- and subsequent IR-values.Comment: 15 pages, 4 figure

Nitrogen transport in the orchid mycorrhizal symbiosis - further evidence for a mutualistic association.

Mycorrhizas are symbioses integral to the health of plant-based ecosystems (Smith & Read, 2008). In a typical mycorrhizal association, fungi in, or on, plant roots pass soil-acquired inorganic nutrients and water to the plant host. In return, the host transfers excess photosynthate to the fungus

New Russulaceae species in south-east Queensland

Russula species are ectomycorrhizal basidiomycetes common throughout Australian woodlands. Molecular and morphological examination of Russula specimens from various sites in South-east Queensland has uncovered a number of phylogenetically diverse and potentially undescribed specimens. At this stage, most of these remain as individual specimens. However, several specimens have been grouped into project species. In this presentation, two potentially new species of Russula will be described. Both species are widespread on red to black clay soils in the Toowoomba region and appear to be phylogenetically related to each other. Project species 1 has a white stipe which developed a pink flush after collection and red to pink centrally depressed cap with white gills. The spores of this species were subglobose, white and ornamented with amyloid warts connected in short chains. The second species, project species 3, is macroscopically similar, differing with its larger size, purple-pink cap colour, and rougher cap texture. Its spores are globose to subglobose, white and ornamented with small amyloid warts connected in short chains. Continued molecular and morphological studies of the Russula species of South-east Queensland may uncover more novel Australian species

A trigger study of CP-violation and lifetimes in Bs → J/ψφ decays in ATLAS

The CP-violating phase φ_s is measured in B_s → J/ψφ decays, using data from the 2010 to 2012 run periods of the ATLAS detector at the LHC at CERN. This measurement potentially provides a means to falsifying the standard model, known to provide insufficient levels of CP-violation to account for the observable universe. This thesis focuses on the trigger selections used in the analysis of the ATLAS data and includes material produced for public papers and ATLAS CONF notes. These include a study of a shift in the reconstructed mass of J/ψ candidates, an optimisation of trigger selections and cuts applied to 2011 data, and a full description of a correction for application to a trigger bias present in the early 2012 data. The measurements presented in this thesis complement and are competitive with measurements made at other experiments around the world. Results were obtained from the final 2012 fit of combined corrected L2StarA and unbiased L2StarB data and the main parameters extracted, where Γ_s is the lifetime, ∆Γ is the width difference, and φ_s is the weak phase, and the errors shown are statistical and systematic respectively: Γ_s = 0.6706±0.0024±0.0022 ∆Γ = 0.0816±0.0086±0.0031 φ_s = -0.2340±0.0718±0.019