Can digital discussion support tools provide cost-effective options for agricultural extension services?

Agricultural extension that delivers timely, targeted, and cost-effective support to farmers will help ensure the sustainability and adaptive capacity of agriculture, enhancing both food security and environmental security. Leveraging advances in agriclimate science and adult education, innovative digital technologies offer significant new opportunities to engage with farmers and to support decision making. In this study, animated video clips (machinimas), developed using the Second LifeTM virtual world gaming platform, model conversations around climate risk and critical on-farm decisions in the Australian sugarcane farming industry. Early evaluation indicates that this is an engaging format that promotes discussion by leveraging farmers’ natural modes of information gathering and social learning. Comparison with conventional extension practices indicates that these discussion support tools may be a cost effective addition to existing approaches. The format’s flexibility means machinimas are readily updated with new information and customized to meet the needs of different farmer groups. Rapid growth in digital access globally and the scalability of such approaches promise greater equity of access to high-value information, critical to better risk management decision making, at minimal cost, for millions of farmers

Observing the temperature dependent transition of the GP2 peptide using terahertz spectroscopy

The GP2 peptide is derived from the Human Epidermal growth factor Receptor 2 (HER2/nue), a marker protein for breast cancer present in saliva. In this paper we study the temperature dependent behavior of hydrated GP2 at terahertz frequencies and find that the peptide undergoes a dynamic transition between 200 and 220 K. By fitting suitable molecular models to the frequency response we determine the molecular processes involved above and below the transition temperature (TD). In particular, we show that below TD the dynamic transition is dominated by a simple harmonic vibration with a slow and temperature dependent relaxation time constant and that above TD, the dynamic behavior is governed by two oscillators, one of which has a fast and temperature independent relaxation time constant and the other of which is a heavily damped oscillator with a slow and temperature dependent time constant. Furthermore a red shifting of the characteristic frequency of the damped oscillator was observed, confirming the presence of a non-harmonic vibration potential. Our measurements and modeling of GP2 highlight the unique capabilities of THz spectroscopy for protein characterization.Yiwen Sun, Zexuan Zhu, Siping Chen, Jega Balakrishnan, Derek Abbott, Anil T. Ahuja and Emma Pickwell-MacPherso

A Computational Exploration of the Color Gamut of Nanoscale Hollow Scalene Ellipsoids of Ag and Au

Hollow, nanoscale, scalene ellipsoids of Ag or Au provide an exceedingly tunable localized surfaceplasmon resonance. Here, we use numerical simulations to determine the limits of the color space that would be possible from colloidal suspensions of these particles and show that their color gamut will exceed that possible with nanorods, nanoshells, or nanorice. The important parametersare composition, thickness of the shell, and shape of the particle, in that order. The sensitivity of colors to geometry is optimized for an aspect ratio of between 0.3 and 0.5 and was reduced for thinner shells. Shells of Ag will have much wider and more vibrant gamut than those of Au. These findings indicate that hollow scalene ellipsoids could be used as versatile pigments in materials or display systemsthat exploit plasmon resonance to produce color

Sensors based on monochromatic interrogation of a localised surface plasmonresonance

The localised surface plasmon resonance in gold nanoparticles can be used as the basis of a refractometric sensor. Usually, this is accomplished by monitoring a shift in wavelength of the resonance peak, a task which requires measurements over a range of wavelengths. Here we investigate a different scheme, in which interrogation of the sensor is carried out at a single wavelength. We have used numerical simulations to estimate the effect that the shape of gold nanoparticles would have on the performance on such sensors. A variety of geometries of gold nanoparticles were investigated, including nano-spheres, nano-rods, nano-triangles, and nano-bowties. The performance of a sensor that operates at a single wavelength is controlled by dT/dn, the change in transmittance T with refractive index n, determined at the interrogation wavelength. In turn, dT/dn depends upon the extinction cross-section of the nanoparticles at the chosen wavelength, and on the density of the nanoparticles in the light path. Contributions to the sensor efficiency also include the shift in wavelength of the plasmon resonance and, importantly, the peak sharpness. Of the particles examined, gold nano-rods will provide the most sensitive sensors by a large margin

Martensite destabilization in Au7Cu5Al4 shape-memory alloy

Aging-induced changes in the austenite peak (AP) temperature of Au7Cu5Al4 shape-memory alloy are investigated. Whereas heat treating the parent phase at temperatures >140 degrees C or aging the martensite for long times at room temperature both stabilized the AP to approximately 80 degrees C, low-temperature excursions into the parent phase caused the subsequent AP to drop to approximately 60 degrees C and the transformation hysteresis to decrease. The evidence indicates that this destabilization of the martensite is caused by time-dependent relaxation of elastic constraint due to parent-phase lath migration during the preceding low-temperature austenitizing treatment. This mechanism of aging is different from that of the better-known symmetry-conforming short-range order phenomenon

A South Australian registry of biphasic cardioversions of atrial arrhythmias: efficacy and predictors of success

Abstract not foundMelanie R. Wittwer, Sharmalar Rajendran, Jill Kealley, Margaret A. Arstal

Erratum: The versatile colour gamut of coatings of plasmonic metal nanoparticles (Physical Chemistry Chemical Physics (2009) 11 (5897-5902) DOI: 10.1039/b903318a)

We have investigated the colour gamut of coatings produced by the growth of plasmonically-active coatings of cap-shaped Au or Ag nanoparticles on a transparent substrate. The control of colour and spectral selectivity that can be obtained by the manipulation of the rates of nucleation and growth were explored using a combination of experiment and calculation. In our experimental work the Au nanoparticles were grown in situ using a wet chemical electroless plating technique while the Ag nanoparticles were produced by physical vapour deposition. The optical properties were numerically simulated using the discrete dipole approximation. The resulting measured or calculated transmission spectra were mapped to the CIE L-a*-b* colour space. The aspect ratio of the nanoparticles was the primary factor in determining the colours in both cases. However, increasing the nucleation rate of the particles resulted in them becoming more closely packed, which also red-shifted the optical extinction peak of the structure due to interactions of their near-fields. This caused an enhancement in the blue component of the transmitted light. Coatings of Ag particles had a significantly wider and brighter colour gamut than those of Au. © the Owner Societies