Outline of an environmental information system.

The development of an environmental information system necessitates a phased implementation approach. Phase 1 includes the elements that are traditionally viewed as comprising monitoring and assessment activities. Analysis tools for interpretive work are identified including statistics, modelling, and GIS. Phase 2 follows the information flow beyond project reporting to examine the process of decision making. The inclusion of other forms of knowledge beyond the strictly scientific is necessary where the development of multi-sectoral decisions must be made. Phase 3 extends the decision-making process to the policy development and implementation field. This is accomplished by the inclusion of expert systems as advanced decision support systems which enable the manager to test various hypotheses and policy options prior to commitment. In addressing water resource issues, the importance of setting achievable and enforceable sectoral criteria and standards for industrial, agricultural, and drinking water supplies is discussed with reference to both usage and effluent criteria. Quality assurance and control is an area which must be critically addressed in any water resource project. The implementation of quality control programs must extend from the field sampling procedures and laboratory standard methods to both inter- and intra-laboratory tests and the development and maintenance of databases.

Evaluation of the effects of acid precipitation in eastern Canada using the raison system.

Evaluations have been made of the key chemical factors in the aquatic effects upon surface waters due to acidic precipitation in eastern Canada. The region of Canada east of the Manitoba/Ontario border was divided into 22 aggregates and assessments of inorganic and organic ion chemistry appraised relative to sulphate deposition rates and distributions. Aquatic sensitivity is largely dominated by the concentration, distribution and magnitude of SO inf4 (sup2-) (sulphate) deposition and by the prevalent geology and derived soils found in each aggregate. The RAISON system provided an adaptable and highly flexible platform to evaluate interactively, multiple data sets of divergent characteristics. Attributes usually associated with geographical information systems are significantly augmented by quantitative numerical and stochastic capabilities that were used extensively in this study.

Depth perception and subjective contours.

A distinction can be made between subjective lines and edges, and subjective lines of the Kennedy-type which suppress (are epistatic to) illusory depth defined by differences of shade.

Ehrenstein variations.

Radial lines pointing towards a central circular region induce an illusory positive brightness contrast. Shift in line orientation from radial to tangential can result in negative brightness contrast and line enhancement.

A sensitive manual enzyme immunoassay for thyroxine.

We describe an immunoassay for thyroxine in serum. In the assay specific antibody covalently bonded to latex particles is used, along with horseradish peroxidase as the label, and o-phenylenediamine as the chromogen. The flexible protocol is designed for manual execution. Performance is similar to that of the highest-sensitivity thyroxine radioimmunoassays. Results correlate well with radioimmunoassay (r = 0.99, slope = 0.93, y-intercept = 2.4 microgram/liter for 201 samples) and an automated enzyme immunoassay (r = 0.97, slope = 0.99, y-intercept = 4.7 coefficients of variation are less than 7.2% over the entire useful range of the assay (20--240 microgram/liter). The limit of detection is less than 94 pg/tube at 20 microgram/liter. Only D-thyroxine is known to interfere with serum assays. This assay has no discernible protein effect from 40 to 80 g of protein per liter, unlike many thyroxine radioimmunoassays. Serum preservatives known to be peroxidase inhibitors do not adversely affect assay performance because of the 56-fold dilution in the final assay mixture. Hemolyzed serum and EDTA-treated plasmas are unsuitable for this assay.

Solid-phase enzyme immunoassay for herpes simplex virus.

An enzyme immunoassay was used for the rapid detection of herpes simplex virus type 1 (HSV-1). The test utilized specific antibodies to HSV-1 attached to a solid phase. A laboratory preparation of HSV-1 was detectable in amounts of greater than or equal to 50 50% tissue culture-infective doses by this method. Tests performed with clinical samples indicated a specificity of 95%. The sensitivity appeared to depend on the length of time the samples were stored. When samples were stored frozen for three to six months, the sensitivity was 46% of that of tissue culture isolations performed when the samples were first collected. The sensitivity was 89% in comparison with attempts at tissue culture reisolation with the same samples at the time of enzyme immunoassay. The immunoassay also detected HSV in seven of 10 positive samples that were stored frozen for no more than two weeks before testing.