Training for an agricultural discrimination task

Skeleton weed, centaurea juncea, is a declared weed in Western Australia because it competes with grain crops for nutrients and moisture. When it is found during harvesting, mechanised teams search and eradicate it. In an earlier report of field trials (Hartley et al, 1989) it was reported that search teams' detection rate was poor and since search teams had usually never seen skeleton weeds, visual discrimination learning was to be expected and observed during searches. The present study investigated the nature of this discrimination learning in a laboratory by developing a training programme of colour photographic slides of weeds in stubble. Subjects receiving specific training with feedback on their performance compared with those receiving pseudo-training showed a significant improvement in detections. Subsequently the benefit of the programme was validated in a field trial.     

The 9-hexadecenoic and 11-octadecenoic acid content of natural fats and oils

The monoenoic methyl esters from numerous fats and oils which contained appreciablecis-9-hexadecenoic acid (cis-9-16∶1) were isolated by liquid-solid chromatography on silver nitrate-silica gel. Analysis of the monoenes by packed and capillary column gas-liquid chromatography showed that significant amounts ofcis-11-octadecenoic acid (cis-11-18∶1) were present in all samples. The amount ofcis-11-18∶1 found in the monoenoic methyl esters increased proportionally to logarithmic increases in thecis-9-16∶1 level. Most analyses reported in the literature also show this proportionality. This mathematical relationship suggests that chain elongation ofcis-9-16∶1 tocis-11-18∶1 is a biosynthetic pathway operative in a wide variety of species.     

Kinetics of hydration properties of meat emulsions containing various fillers during smokehouse cooking

The cooking kinetics of meat emulsions containing various fillers was determined by monitoring changes in hydration properties such as cooking loss and water-holding capacity during smokehouse cooking. Press juice, consumer cook test and emulsion stability of cooked product were also determined. The fillers used were buttermilk powder, corn starch, microcrystalline cellulose, modified corn starch, modified wheat flour, soy-protein concentrate and whey-protein concentrate. The cooking process was modelled using reaction kinetics and Eyring's absolute reaction rate theory. Enthalpy and entropy changes of activation were calculated for various properties and fillers.     

Multiple field of view lidar returns from atmospheric aerosols

As a laser pulse propagates into the atmosphere, it becomes broader in the lateral direction as a result of scattering by aerosols. The laser pulse may be described as the superposition of a central, unscattered component of reduced intensity and a surrounding scattered component. A multiple field of view lidar has been developed that makes simultaneous measurements of the backscattered power from the central pulse and multiply scattered power arising from the scattered component. Measurements from various types of atmospheric aerosols and precipitation are presented and compared with simulated returns. The results show how the multiply scattered signals are influenced by the distribution of the aerosols along the lidar path, the characteristic size of the aerosols, and the optical depth. It is shown that the multiple field of view lidar can provide meaningful, additional information about the aerosols that is not available from a conventional single field of view lidar.     

Multiple-scattering lidar equation

A multiple-scattering lidar equation is derived from a phenomenological representation of the scattering processes. The contributions are separated into the unscattered, singly scattered, and multiply scattered illumination of the scattering volume, a single backscattering reflection from that volume, and the unscattered and multiply scattered propagation back to the receiver. The equation is obtained in the form of analytic expressions that explicitly show the signal dependence on the extinction coefficient, the effective particle size, the range, and the receiver field of view. Consistent agreement is found with Monte Carlo calculations and published laboratory measurements. Numerical simulations demonstrate that measurements made at three or more fields of view can be inverted to solve for the extinction coefficient and the effective particle radius. The multiple scatterings taken into account in the proposed equation are the small-angle diffraction scatterings; the wide-angle scatterings caused by refraction and reflection are considered lost, except for one backscattering at an angle close to 180°. Consequently, the equation is applicable to cases in which the projection of the lidar receiver field of view on the cloud is of the order of the angular width of the diffraction peak of the phase function times the penetration depth into the cloud.     

Development and applications of surface-activated chemical ionization

This review regards the recently developed ionization source named surface-activated chemical ionization (SACI) that employs an interaction with a surface placed at low voltage for the activation of the ionization of sample molecules to increase the sensitivity in the analysis of various compounds of biological and clinical interest. These results are due to the strong chemical noise decrease and the increase of ionization efficiency. This ionization source has been employed for the analysis of various compounds of different molecular mass and polarity (addicted and pharmaceutical drugs, amino acids, steroids, peptides, and proteins). The SACI development theoretical mechanism, benefits, disadvantages, applications, and future developments are reported and discussed.