A&L Canada Laboratories (Canada)

Harmful algal blooms (HABs) in coastal British Columbia (BC), Canada, negatively impact the salmon aquaculture industry. One disease of interest to salmon aquaculture is Net Pen Liver Disease (NPLD), which induces severe liver damage and is believed to be caused by the exposure to microcystins (MCs). To address the lack of information about algal toxins in BC marine environments and the risk they pose, this study investigated the presence of MCs and other toxins at aquaculture sites. Sampling was carried out using discrete water samples and Solid Phase Adsorption Toxin Tracking (SPATT) samplers from 2017-2019. All 283 SPATT samples and all 81 water samples tested positive for MCs. Testing for okadaic acid (OA) and domoic acid (DA) occurred in 66 and 43 samples, respectively, and all samples were positive for the toxin tested. Testing for dinophysistoxin-1 (DTX-1) (20 samples), pectenotoxin-2 (PTX-2) (20 samples), and yessotoxin (YTX) (17 samples) revealed that all samples were positive for the tested toxins. This study revealed the presence of multiple co-occurring toxins in BC's coastal waters and the levels detected in this study were below the regulatory limits for health and recreational use. This study expands our limited knowledge of algal toxins in coastal BC and shows that further studies are needed to understand the risks they pose to marine fisheries and ecosystems.

Unmanned aircraft systems (UAS) have been proven cost- and time-effective remote-sensing platforms for precision agriculture applications. This study presents a method for automatic delineation of field areas and boundaries that uses UAS multispectral orthomosaics acquired over 7 vegetated fields having a variety of crops in Prince Edward Island (PEI). This information is needed by crop insurance agencies and growers for an accurate determination of crop insurance premiums. The field areas and boundaries were delineated by applying both a pixel-based and an object-based supervised random forest (RF) classifier applied to reflectance and vegetation index images, followed by a vectorization pipeline. Both methodologies performed exceptionally well, resulting in a mean area goodness of fit (AGoF) for the field areas greater than 98% and a mean boundary mean positional error (BMPE) lower than 0.8 m for the seven surveyed fields.

In this paper we examine the creation of Whitenoise super keys. A Whitenoise key is an exponential length key that can be used as a one-time-pad and that can in turn create an unlimited number of unique keys. Because its structure is more akin to the mechanical Enigma it is not vulnerable to arithmetic attacks. Because they are random they are resistant to brute force and quantum computing attacks.

A simplified approach in the use of focused microwave systems for the investigation of radially varying plasmas is assessed by comparison to electrostatic probes on a dc arc argon jet. The approach consists in the mathematical inversion into a radial electron density distribution, of a fit to the phase shift profile obtained by scanning a focused interferometer across a cylindrical plasma. A close fit given by Bockasten's coefficient method, and a loose fit utilizing a modified Gaussian, are considered. The assessment covers a wide range of radial refractive index gradients (as large as 0.4/cm) with electron density up to critical on axis. The modified Gaussian fit approach shows a maximum disagreement of 25% relative to the probe results for an impact parameter smaller than 0.5 and of 350% across the plasma jet. A simple modification to the method would apparently permit the reduction of the overall discrepancy to less than 30%. The close fit is found to yield discrepancies which are worse by a factor of 2–3.