Integrating advanced technologies for optimization of aerial herbicide applications

Aerial application of herbicides continues to be a dominant method of vegetation control in Canadian forest management. In this paper, we describe a suite of relatively modern technologies and emphasize their potential for integrated use in optimization of aerial herbicide treatments. The potential is illustrated using several case studies involving fixed-wing applications of glyphosate-based herbicide in the boreal forest region of Ontario, Canada. Results indicate that integration of geographic information systems, differential global positioning, electronic-guidance, on-site meteorological monitoring and remote sensing can be used to effectively plan, enhance application control and provide detailed post-treatment assessment and archival data for herbicide spray programs. SprayAdvisor, a GIS-based decision support system with the capacity to directly integrate all of these elements is briefly described.     

Immune responses to non-structural protein 3 (NS3) of bovine viral diarrhoea virus (BVDV) in NS3 DNA vaccinated and naturally infected cattle

Immune responses to non-structural protein 3 (NS3) of bovine viral diarrhoea virus (BVDV) were investigated. cDNA encoding NS3 from type 1a BVDV was used to vaccinate five calves, another five calves remained unvaccinated. Three weeks after final vaccination animals were challenged intranasally with heterologous type 1a BVDV. Anti-NS3 antibodies were detected in only one animal post-vaccination. Partial protection from virus challenge was observed in the vaccinates. Virus was not isolated from nasal mucosa of two vaccinates, and virus clearance from nasal mucosa was faster in the vaccinates compared to the controls. While elevated rectal temperatures were evident in both groups 7 days post-challenge, the mean increase in the controls was twice that observed in the vaccinates. In conclusion, NS3 DNA vaccination induced humoral immunity in one calf, and prevented fever and virus establishment in the nasal mucosa in 2/5 calves, demonstrating the efficacy of NS3 vaccination, which may benefit future development of pestivirus and flavivirus vaccines.     

Use of surface plasmon resonance (SPR) to study the dissociation and polysaccharide binding of casein micelles and caseins

Tests were made to determine whether surface plasmon resonance (SPR) could be used as a technique to study the dissociation properties of bovine casein micelles or of sodium caseinate and the interactions between these protein particles and different polysaccharides. Surfaces of bound micelles or caseinate were made, and the changes in refractive index of these layers were used to define changes in the structures of the chemisorbed material. The technique appears to have some potential for studying details of the dissociation of casein micelles and of the binding of different polysaccharides to caseins.     

Possible pseudogout in two dogs

Pseudogout, the acute form of calcium pyrophosphate deposition disease, is a common condition in elderly human beings and is characterised by the sudden onset of intense joint pain and synovitis. It is rarely identified in animals but was diagnosed in two dogs that presented with acute lameness and pyrexia. Cytology of the synovial fluid showed a mildly elevated cell count with both non-degenerate neutrophils and mononuclear cells present. Many of the mononuclear cells and occasional neutrophils contained square or rhomboid-shaped crystals that were variable in shape and size and weakly birefringent on examination under polarised light. Clinical signs resolved following treatment with prednisolone.     

Paleontological Evidence of Varitions in Length of Synodic Month since Late Cambrian

The values of length of synodic month, obtained from tidally controlled periodical growth patterns in mollusks and stromatolites for several geologic periods, indicate that the deceleration rate of the earth's rotation has not been constant. Two breaks in slope, in the Pennsylvanian and Cretaceous, may be related to changes in distribution of continents, oceans, and adjacent shallow seas.     

Intake and discharge nutrient loads at three intensive shrimp farms

This study was conducted to help provide a framework for Australian regulation of shrimp farm siting and discharges. Monitoring of farm water usage, and intake and discharge water quality was conducted at three commercial intensive shrimp farms, chosen to represent different operating environments, latitudes, cultured species and management styles. Weekly samples were taken over 3 years, for 3–12 months at each farm, to investigate intake and discharge concentrations and loads of total suspended solids (TSS), total nitrogen (TN) and total phosphorus (TP). Mean water exchange was 1.4 ML ha^?1 day^?1 (about 10% day^?1) at the first farm studied and 0.5 ML ha^?1 day^?1 (about 3.6% day^?1) at the others. Farm mean discharge concentration varied as follows: TSS, from 36.9 to 119 mg L^?1; TN, from 2.1 to 3.1 mg L^?1 and TP, from 0.22 to 0.28 mg L^?1. Farm mean intake concentrations were from 11% to 91% of equivalent mean discharge concentration (for TN at Farm B and TSS at Farm C respectively). Mean net discharge loads, related to area of production ponds at each farm, varied as follows: TSS, from 4.8 to 85.7 kg ha^?1 day^?1; TN, from 1 to 1.8 kg ha^?1 day^?1 and TP, from 0.11 to 0.22 kg ha^?1 day^?1. The highest net loads of TSS, TN and TP were all from the farm with the highest water exchange rate, located on a coastal river, and studied during a year of high rainfall with associated poor water quality. These results can be used to help predict likely discharge characteristics for new shrimp farms, and provide a benchmark against which to evaluate future improvements in shrimp farm environmental management.     

Opto-electronic counters for postlarvae and juveniles of Machrobrachium rosenbergii (de Man); design and tests of Type A counter

Postlarvae or juveniles of Macrobrachium rosenbergii produced in Mauritius are sold at unit price to prawn farmers and are counted individually by hand. This process is time consuming, labour intensive, subject to error and may stress the juveniles; safe rapid electronic counting would be highly advantageous.The design of the hydraulic component of a successful counter prototype, Type A, is described. The counter has 10 parallel channels through which juveniles are carried in a water current. The detection of juveniles passing through these channels can be done photo-electrically. The counter accepts juveniles up to 15 mm in length (eye orbit to tip telson) and has the significant advantage that it can be constructed using only simple hand tools.Survival and growth rate tests, and microscopic examination for damage to appendages of juveniles were done on machine counted and hand counted juveniles. There was no reduction of growth or survival caused by passage through the counter by comparison with the hand counting method, and it is concluded that the counter is not detrimental to juvenile prawns.About 70% of all juveniles tested showed highly variable amounts of damage. The great majority of this damage appears to originate in the hatchery tanks, prior to the experimental treatments. Only in the case of antennules could the use of the counter be shown to increase damage significantly, i.e. from 25% to 38%, but this has no detectable effect on subsequent survival or growth.This appears to be the first counter made specifically for counting macroscopic crustacean juveniles, and via suitable scaling, adaptation to counting other species of crustaceans, fish larvae, etc., should be possible.     

Triple-cross hybrid kale

A triple-cross method is described as an alternative to the double-cross method for the production in kale of 100 per cent hybrid seed. This new method would reduce the labour involved and improve yields in the early stages of seed multiplication. These advantages would justify slightly lower yields of forage from triple-cross hybrids than from double-crosses.