Multi-sensor and data fusion approach for determining yield limiting factors and for in-situ measurement of yellow rust and fusarium head blight in cereals

The world’s population is increasing and along with it, the demand for food. A novel parametric model (Volterra Non-linear Regressive with eXogenous inputs (VNRX)) is introduced for quantifying influences of individual and multiple soil properties on crop yield and normalised difference vegetation Index. The performance was compared to a random forest method over two consecutive years, with the best results of 55.6% and 52%, respectively. The VNRX was then implemented using high sampling resolution soil data collected with an on-line visible and near infrared (vis-NIR) spectroscopy sensor predicting yield variation of 23.21%. A hyperspectral imager coupled with partial least squares regression was successfully applied in the detection of fusarium head blight and yellow rust infection in winter wheat and barley canopies, under laboratory and on-line measurement conditions. Maps of the two diseases were developed for four fields. Spectral indices of the standard deviation between 500 to 650 nm, and the squared difference between 650 and 700 nm, were found to be useful in differentiating between the two diseases, in the two crops, under variable water stress. The optimisation of the hyperspectral imager for field measurement was based on signal-to-noise ratio, and considered; camera angle and distance, integration time, and light source angle and distance from the crop canopy. The study summarises in the proposal of a new method of disease management through suggested selective harvest and fungicide applications, for winter wheat and barley which theoretically reduced fungicide rate by an average of 24% and offers a combined saving of the two methods of £83 per hectare

Novel imprinted polymers as artificial enzymes

Derivatives of L-histidine were investigated as suitable models for the Asp-His couple found in the catalytic triad of serine proteases. A combination of molecular dynamics and IH NMR spectroscopy suggested that the most populous conformations of N-acetyl-L-histidine and the N-acetyl-L-histidine anion were predominated by those in which the carboxylate group was gauche to the imidazole ring overcoming steric and electrostatic repulsion, suggesting there is an interaction between the carboxylate group and the imidazole ring. Kinetic studies, using imidazole, N-acetyl-L-histidine and the N-acetyl-L-histidine anion showed that in a DMSO/H20 9: 1 v/v solution, the N-acetyl-L-histidine anion catalysed the hydrolysis of p-nitrophenyl acetate at a greater rate than using either imidazole or N-acetyl-L-histidine as catalyst. This indicates that the carboxylate group affects the nucleophilicity of the unprotonated imidazole ring. 31P MAS NMR spectroscopy was investigated as a new technique for the study of the template molecule environment within the polymer networks. It was found that it was possible to distinguish between template associated with the polymer and that which was precipitated onto the surface, though it was not possible to distinguish between polymer within imprinted cavities and that which was not. Attempts to study the effect of the carboxylate group/imidazole ring interaction in the imprinted cavity of a molecularly imprinted polymer network were hindered by the method used to follow the reaction. It was found though that in a pH 8.0 buffered solution the presence of imprinted cavities increased the rate of reaction for those polymers derived from L-histidine. Some preliminary investigations into the design and synthesis of an MIP which would catalyse the oxy-Cope rearrangement were carried out but the results were inconclusive

Density Functional Theory Calculations Complement Mass Spectrometry Experiments in the Investigation of Biomass Fast Pyrolysis and Ion-Molecule Reaction Mechanisms

Biomass fast-pyrolysis, or the rapid heating in the absence of oxygen, is a promising method for biomass conversion necessary for a renewable energy economy. Although kinetic models of cellulose pyrolysis have existed since the 1970s, current models and hypothesized reaction networks fail to explain the product distribution even for a simple model compound, the cellulose dimer, cellobiose. A novel approach of using mass spectrometry to instantly characterize fast pyrolysis vapors allows for identification of initial products to help delineate the reaction pathways that dictate the final product distribution of fast pyrolysis of biomass and model compounds. The use of this set-up to study fast pyrolysis of glucosaccharide-based compounds, such as cellobiose, 13C-labeled cellobiose, cellohexaose, cellotriosan, and cellulose has revealed that the reaction pathway of unraveling the reducing end of the polysaccharide by multiple losses of glycolaldehyde (or isomer) is competitive with the well-established mechanism of levoglucosan production via nucleophilic attack of the hydroxymethylene group at the anomeric carbon concerted with glycosidic bond cleavage. Computational investigation on the reaction barriers of this reducing end unraveling mechanism in tandem wit

Optimising configuration of a hyperspectral imager for on-line field measurement of wheat canopy

There is a lack of information on optimal measurement configuration of hyperspectral imagers for on-line measurement of a wheat canopy. This paper aims at identifying this configuration using a passive sensor (400–750 nm). The individual and interaction effects of camera height and angle, sensor integration time and light source distance and height on the spectra's signal-to-noise ratio (SNR) were evaluated under laboratory scanning conditions, from which an optimal configuration was defined and tested under on-line field measurement conditions. The influences of soil total nitrogen (TN) and moisture content (MC) measured with an on-line visible and near infrared (vis-NIR) spectroscopy sensor on SNR were also studied. Analysis of variance and principal component analysis (PCA) were applied to understand the effects of the laboratory considered factors and to identify the most influencing components on SNR. Results showed that integration time and camera height and angle are highly influential factors affecting SNR. Among integration times of 10, 20 and 50 ms, the highest SNR was obtained with 1.2 m, 1.2 m and 10° values of light height, light distance and camera angle, respectively. The optimum integration time for on-line field measurement was 50 ms, obtained at an optimal camera height of 0.3 m. On-line measured soil TN and MC were found to have significant effects on the SNR with Kappa values of 0.56 and 0.75, respectively. In conclusion, an optimal configuration for a tractor mounted hyperspectral imager was established for the best quality of on-line spectra collected for wheat canopy

Service providers’ experience of methamphetamine and the portrayal of the ‘ice epidemic’ in remote Australia

Objective: To contrast service providers’ perceptions about crystalline methamphetamine (henceforth, ice) use and harm with information communicated in media reports and politicians’ statements. Design: In-depth semi structured interviews with service providers about the nature and extent of ice use in the local community and its impact on individual services, clients and town life. Interviews were transcribed verbatim, manually analysed and coded around key themes, interpreted and independently cross-checked for context and accuracy. Setting: Two remote towns located in different states and territories operating as service hubs to very remote communities. Participants: Twenty-seven key service providers representing local organisations that engage with ice users and/or their families. Results: First, compared with alcohol, ice use and ice-related harm were insignificant at the two sites. Ice users were primarily high-earning and -functioning non-Australian Aboriginal tradesmen, and to a lesser extent, professionals and secondary school students. There were few Australian Aboriginal users. Ice was used to ‘party’, keep alert, and escape psychological distress. Second, the ‘Ice Destroys Lives’ campaign and references to an ‘ice epidemic’ amplified public anxiety about ice and ice-related harm in the surveyed communities. Third, the attention on ice distracted from the more extensive harm arising from alcohol use in their communities. Conclusion: The respondents questioned the notion of an ‘ice epidemic’ and the use of federal funding for ice-related initiatives in remote communities, especially while general alcohol and other drug services were under-resourced