Effects of mechanically separated dairy cow slurry on grazing performance

No abstract available

The nitrogen supplying power of alfalfa in irrigated crop rotations

Non-Peer Reviewe

How Old is My Bronze Cannon? A laboratory exercise linking analytical chemistry, spectroscopy and metallurgy

Details are provided of a simple, quick, and safe laboratory exercise to analyze the tin content of a bronze sample. The experiment is set in the context of analyzing filings from a bronze artefact (“cannon”) of unknown origin. Students work in teams to complete separate parts of the experiment and to produce replicate sets of results. The procedure is designed in such a way as to demonstrate the basic principles of oxidation and reduction, spectroscopy and analytical chemistry at a level suitable for upper secondary school students. It also provides an opportunity to introduce students to advanced analytical instrumentation that is not generally available in secondary schools. The experiment was developed to be completed in a single 50 minute session and has been successfully conducted with over 200 middle- to upper-level secondary school students

The effect of anhydrous ammonia on Saskatchewan soils

Non-Peer Reviewe

Investigation of mono-, bis- and tris-glycinatochromium(III): Comparisons of computational and experimental results

The synthesis and characterization of mono-, bis- and tris-glycinatochromium(III) complexes by elemental analysis, UV–Vis, electron paramagnetic resonance (EPR), ATR-FTIR and Raman spectroscopy has been performed in this work. IR stretching bands obtained from DFT calculations of the mono-, bis- and tris-glycinatochromium(III) complexes are in good agreement with experimental data. Different mechanistic pathways were explored for the water exchange reactions of [Cr(+NH3CH2COO−)(H2O)5]3+ and its conjugate base species including, associative interchange (Ia), and dissociative (D) mechanisms. The lowest activation enthalpies for the mono- and bis-complexes are obtained for the Ia pathways with explicit outer sphere solvation (88 and 76 kJ mol−1), which are in good agreement with the experimental values (87 and 75 kJ mol−1). In comparison, tris-glycinatochromium(III) undergoes aquation via the dissociative (D) mechanism. Investigation of these systems in the pH range ∼3.0 to ∼8.5 by UV–Vis monitoring, helps identify the speciation of these complexes in physiological environments

Mechanistic investigation of halopentaaquachromium(III) complexes: Comparison of computational and experimental results

The mechanism for the substitution reactions of halopentaaquachromium(III) complexes in the series, [CrX(H2O)5]2+, where X = F−, Cl−, Br−, or I− have been investigated using density functional theory. Several different mechanistic pathways were explored including associative interchange (Ia), dissociative (D) and the associatively activated dissociation mechanisms (Da). The lowest overall activation enthalpy (ΔH‡) obtained for the fluoride system is for the Ia pathway, with immediate proton abstraction leading to the formation of HF and the conjugate base. For the chloride, bromide and iodide systems the Da pathway has the lowest ΔH‡ values. Activation enthalpies determined at the PBE0/cc-pVDZ level, in aqueous solution (PCM), are in excellent agreement with the experimental results (MAD is 1.0 kJ mol−1). Reaction profiles were analyzed in terms of activation volumes to explain the observed trends

Bonding in doped gallium nanoclusters: Insights from regional DFT

The molecular nature (Ga2)n of gallium makes this an interesting metal to investigate for the development of novel nano-materials. However, establishment of a targeted approach to manipulating the properties of gallium clusters requires a detailed understanding of how doping affects the bonding in these species. In this study, the bonding of gallium nanoclusters has been investigated using electron deformation densities and Regional Density Functional Theory (RDFT). Bonding throughout Ga12X clusters is generally intermediate between covalent and metallic. However, the presence of Ga2 subunits is clearly identified in clusters with endohedral dopants (Ga12X, X = Al, Si, P, Ga, Ge, As). Although there is evidence of Ga2 subunits in exohedral doped clusters, localised bonding to the dopant generally leads to significant disruption to the cluster framework. Maps of electronic chemical potential provide understanding for the observed differences in regioselectivity for hydrogen adsorption

Organic carbon compounds associated with deep soil carbon stores

Aims Organic carbon has been reported in deep regolithic profiles to depths of tens of metres, but the composition of the carbon compounds is unknown. Methods Residual carbon in the form of non-volatile low molecular weight compounds (LMWC) was characterised in three deep soil profiles to a depth of 19 m under farmland in south-western Australia following extraction with ethyl acetate and analysis by GC/MS. Pyrolysis and off-line thermochemolysis were used to characterise macromolecular organic carbon (MOC) to a depth of 29 m at a fourth site. Results Three compound classes occurred across the three different field locations: (1) terpenes, (2) fatty acids, amides and alcohols, and (3) plant steroids; indicating the influence of input of the past and present vegetation. Compounds related to fatty acids were the predominant residual carbon species in deep soils, and may be derived from plants and microorganisms. Biomarkers such as lignin, polysaccharides, proteins and terpenes at 0–0.1 m implied influences of vegetation, fire events and microorganisms. Pyrolysis found that polysaccharides were distributed mainly from 0 to 0.1 m, while aromatic compounds were consistently detected down to 29 m. Conclusions Carbon was stabilised in the form of aromatic compounds in deep soil, whereas other carbon sources such as cellulose, chitin, and N-containing compounds were confined to the surface soil. LMWC (Z)-docos-13-enamide and bis(6-methylheptyl) phthalate, were the main components throughout the soil profiles representing 53–81% of the LMWC, and were a greater proportion of the organic matter at depths of 18–19 m

Animal thermoregulation: a review of insulation, physiology and behaviour relevant to temperature control in buildings

Birds and mammals have evolved many thermal adaptations that are relevant to the bioinspired design of temperature control systems and energy management in buildings. Similar to many buildings, endothermic animals generate internal metabolic heat, are well insulated, regulate their temperature within set limits, modify microclimate and adjust thermal exchange with their environment. We review the major components of animal thermoregulation in endothermic birds and mammals that are pertinent to building engineering, in a world where climate is changing and reduction in energy use is needed. In animals, adjustment of insulation together with physiological and behavioural responses to changing environmental conditions fine-tune spatial and temporal regulation of body temperature, while also minimizing energy expenditure. These biological adaptations are characteristically flexible, allowing animals to alter their body temperatures to hourly, daily, or annual demands for energy. They exemplify how buildings could become more thermally reactive to meteorological fluctuations, capitalising on dynamic thermal materials and system properties. Based on this synthesis, we suggest that heat transfer modelling could be used to simulate these flexible biomimetic features and assess their success in reducing energy costs while maintaining thermal comfort for given building types

On the control of psychological networks

The combination of network theory and network psychometric methods has opened up a variety of new ways to conceptualize and study psychological disorders. The idea of psychological disorders as dynamic systems has sparked interest in developing interventions based on results of network analytic tools. However, simply estimating a network model is not sufficient for determining which symptoms might be most effective to intervene upon, nor is it sufficient for determining the potential efficacy of any given intervention. In this paper, we attempt to remedy this gap by introducing fundamental concepts of control theory to both psychometricians and applied psychologists. We introduce two controllability statistics to the psychometric literature, average and modal controllability, to facilitate selecting the best set of intervention targets. Following this introduction, we show how intervention scientists can probe the effects of both theoretical and empirical interventions on networks derived from real data and demonstrate how simulations can account for intervention cost and the desire to reduce specific symptoms. Every step is based on rich clinical EMA data from a sample of subjects undergoing treatment for complicated grief, with a focus on the outcome suicidal ideation. All methods are implemented in an open-source R package netcontrol, and complete code for replicating the analyses in this manuscript are available online.Stress and Psychopatholog