Spatiotemporal Mapping of Electrochemical Diffusion Layers

Although pure electrochemical techniques can provide substantial knowledge about electrochemical reaction mechanisms, they lack the ability to provide direct molecular structure information about the species involved. This inability to extract molecular information can result in mechanistic ambiguity with respect to the identity of the reaction intermediates. This information can be obtained by coupling in situ spectroscopic methodologies with electrochemical techniques. This is known as spectroelectrochemistry. A particularly problematic area of study with spectroelectrochemical techniques is the analysis of the mass transport of species within the diffusion layer of the electrode. The visualization of the diffusion layer surrounding electrodes allows for the unambiguous determination of electrode processes. However, a high degree of spatial and temporal resolution is needed as the diffusion layer in a typical electrochemical reaction extends to a thickness of hundreds of microns in tens of seconds. While traditional infrared spectroelectrochemical techniques have been valuable for the study of electrochemical processes, they do not provide the spatial and/or the temporal resolution that is needed to examine the diffusion layers produced at electrodes. This thesis focuses on the development of an IR technique that couples synchrotron based IR radiation (SIR) with electrochemistry, allowing for the concentrations of species present within the diffusion layer of an electrode to be mapped during an electrochemical reaction. The reduction of ferricyanide and oxidation of hydroquinone (HQ) are used as test redox systems to study the ability of SIR to map electrochemical diffusion layers. The resulting diffusion coefficients of ferricyanide, ferrocyanide, hydroquinone and benzoquinone are extracted using the IR method developed here and compared to those determined independently by hydrodynamic linear sweep voltammetry (HLSV). The diffusion coefficients of all species as determined by SIR diffusion layer mapping will be shown to be consistent with the diffusion coefficients determined by HLSV. This validates the ability of SIR diffusion layer mapping to monitor electrochemically generated diffusion layers

Nutrient export in run-off from an in-field cattle overwintering site in east-central Saskatchewan

Non-Peer Reviewe

Evaluating Airsoft Electric Guns for Control of Invasive Brown Treesnakes

Firearms are often used in lethal control of invasive vertebrates, but safety and regulatory aspects limit the circumstances under which they can be used. During August 2016 at the Brown Treesnake Project laboratory on Guam, we evaluated hobby‐grade Airsoft Electric Guns (AEGs; a lower powered, less‐hazardous, and less‐regulated alternative to firearms) for capture and control of small animals, with specific emphasis on invasive brown treesnakes (Boiga irregularis). Tests of AEGs differing in power with ammunition (plastic pellets) masses ranging from 0.20 to 0.39 g, fired at gelatin blocks from distances of 4, 8, and 12 m, showed that heavy ammunition is of overriding importance for maximizing lethality: 0.39‐g pellets penetrated more deeply at 12 m than did 0.20‐g pellets at 4 m. Inspection of tissue damage in brown treesnake carcasses subjected to fire with the 0.39‐g ammunition from the same distances suggested that injuries sustained by a direct hit from 12 m would often be lethal, and snakes would be unlikely to survive multiple hits from automatic fire discharged at approximately 17/s. Limited trials with live snakes helped us to understand behavioral responses in a snake hit by ≥1 pellets, including distance traveled over time. Based on these factors, we assessed the risk that a snake injured by pellet fire might evade subsequent capture by rapid responders in the proximity. We also discuss ethical considerations and regulatory advantages of using AEGs

Forage yield and quality, cattle grazing capacity, cost of production and soil carbon in an annual polycrop mixture versus barley swath grazing

Non-Peer ReviewedThe extensive swath grazing systems of barley (Hordeum vulgare) and an annual polycrop mixture were evaluated for forage yield, forage quality, cattle grazing capacity, and cost of production in 2017 and 2018. A 13.2 ha site located at Livestock and Forage Centre of Excellence Termuende Research Ranch was seeded in June and grazing commenced in November of each year. The annual polycrop mixture was Union Forage Ultimate Annual Blend with the addition of 40-10 forage peas (Pisum sativa). The Ultimate Annual Blend included the following species: hairy vetch (Vicia villosa), crimson clover (Trifolium incarnatum), Italian ryegrass (Lolium multiflorum), sorghum (Sorghum bicolor), Winfred forage brassica (Brassica napus ssp. biennis), Hunter Brassica (Brassica rapa syn.B campestris), and Graza Forage Brassica forage brassica (Raphanus sativa ssp. maritimus). The barley cultivar was CDC Maverick barley

Evaluation of nutritional status among school-aged children in rural Kwahu-eastern region, Ghana; anthropometric measures and environmental influences

School-age children in developing countries are particularly vulnerable to undernutrition as the priority of nutritional interventions focus on fetal development and the first years of life. This study examines anthropometric indices of school-age children in five communities located in rural Kwahu-Eastern Region, Ghana, West Africa and discusses environmental influences that contribute to their nutritional and growth status. Anthropometric indices of heights and weights were obtained from 411 school- aged children, (5-12 years old) in 5 villages (Asakraka, Awiseasu, Miaso, Oframase and Oworobong) during June 2012. Anthropometric parameters and influences that contributed to nutritional status (environmental, health facilities, availability of markets and gender) were assessed. Factorial ANOVAs were conducted with age, gender and village as factors for the z-score for ‘BMI-for-age’ and the z-score for ‘height-for-age’. The z-score of ‘BMI-for-age’ showed a significant two-way interaction effect between ‘Age’ and ‘Village’, F (4, 391) = 6.06, p-value < 0.001, η2 = 0.06. The mean z-score for ‘BMI- for-age’ was significantly lower for older children in Oframase. The z-score of ‘Height-for-age’ showed a small but significant three-way interaction effect among ‘Age’, ‘Gender’, and ‘Village’, F (4, 391) = 3.79, p-value = 0.005, η2 = 0.04. The mean z-score for ‘Height-for-age’ was significantly lower in older children (ages 10-12 years) in all villages except Asakraka. Lower mean z-score for ‘Height-for-age’ in older children (ages 10-12 years) remains to be significant in boys in villages of Awiseasu and Oworobong and in girls in villages of Awiseasu, Miaso and Oframase. Children in isolated communities are at increased risk for lower z-scores in ‘Height-for-age’ and ‘BMI-for-age’. Communities with a clinic, paved road and established infrastructure did not demonstrate evidence of chronic malnutrition. Acute malnutrition in the form of lower z-scores was demonstrated in older children in Oframase. Gender disparities are present and increased awareness of the nutritional status of girls needs to be addressed.Keywords: Nutrition, School children, Ghana, Environmen

Legume based pasture rejuvenation for greenhouse gas outcomes

Non-Peer ReviewedIncorporating legumes into a grass based pasture system has multiple benefits. A grass/legume blend increases the dietary protein of foraging cattle over grass alone. Furthermore, symbiotic biological nitrogen fixation introduces additional nitrogen to the pasture system thereby potentially lessening the need for synthetic fertilizers. However, over time, pastures initially seeded with a blend of grasses and legumes will tend towards increasing grass dominance such that the presence and benefits of legumes diminishes. Reestablishing legumes on a mature pasture can restore these important functions. By improving ruminant diet and therefore feed conversion ratios as well as decreasing nitrogen fertilizer applications, pasture rejuvenation, through the introduction of legumes, is expected to lower the greenhouse gas cost of grazing livestock on a per output basis. However, disturbance of soils, which can be part of various rejuvenation techniques, can result in losses of soil carbon thereby offsetting potential at least some of the greenhouse gas benefits. Sod-seeding may be an effective strategy to establish legumes in a mature pasture thereby incurring benefits without heavily disrupting soils and incurring soil carbon loss. To test this, a multiyear experiment, including cattle, vegetation (specifically the incorporation of non-bloat legumes: cicer milkvetch and sainfoin), soils and microbiota, was established near Lanigan, SK to examine the impact of sod-seeded legume pasture rejuvenation on greenhouse gases

Prehistory of Transit Searches

Nowadays the more powerful method to detect extrasolar planets is the transit method. We review the planet transits which were anticipated, searched, and the first ones which were observed all through history. Indeed transits of planets in front of their star were first investigated and studied in the solar system. The first observations of sunspots were sometimes mistaken for transits of unknown planets. The first scientific observation and study of a transit in the solar system was the observation of Mercury transit by Pierre Gassendi in 1631. Because observations of Venus transits could give a way to determine the distance Sun-Earth, transits of Venus were overwhelmingly observed. Some objects which actually do not exist were searched by their hypothetical transits on the Sun, as some examples a Venus satellite and an infra-mercurial planet. We evoke the possibly first use of the hypothesis of an exoplanet transit to explain some periodic variations of the luminosity of a star, namely the star Algol, during the eighteen century. Then we review the predictions of detection of exoplanets by their transits, those predictions being sometimes ancient, and made by astronomers as well as popular science writers. However, these very interesting predictions were never published in peer-reviewed journals specialized in astronomical discoveries and results. A possible transit of the planet beta Pic b was observed in 1981. Shall we see another transit expected for the same planet during 2018? Today, some studies of transits which are connected to hypothetical extraterrestrial civilisations are published in astronomical refereed journals. Some studies which would be classified not long ago as science fiction are now considered as scientific ones.Comment: Submiited to Handbook of Exoplanets (Springer

Anti-invasive and anti-adhesive activities of a recombinant disintegrin, r-viridistatin 2, derived from the Prairie rattlesnake (Crotalus viridis viridis)

Snake venom disintegrins inhibit platelet aggregation and have anti-cancer activities. In this study, we report the cloning, expression, and functional activities of a recombinant disintegrin, r-viridistatin 2 (GenBank ID: JQ071899), from the Prairie rattlesnake. r-Viridistatin 2 was tested for anti-invasive and anti-adhesive activities against six different cancer cell lines (human urinary bladder carcinoma (T24), human fibrosarcoma (HT-1080), human skin melanoma (SK-Mel-28), human colorectal adenocarcinoma (CaCo-2), human breast adenocarcinoma (MDA-MB-231) and murine skin melanoma (B16F10)). r-Viridistatin 2 shares 96% and 64% amino acid identity with two other Prairie rattlesnake medium-sized disintegrins, viridin and viridistatin, respectively. r-Viridistatin 2 was able to inhibit adhesion of T24, SK-MEL-28, HT-1080, CaCo-2 and MDA-MB-231 to various extracellular matrix proteins with different affinities. r-Viridistatin 2 decreased the ability of T24 and SK-MEL-28 cells to migrate by 62 and 96% respectively, after 24 h of incubation and the invasion of T24, SK-MEL-28, HT-1080 and MDA-MB-231 cells were inhibited by 80, 85, 65 and 64% respectively, through a reconstituted basement membrane using a modified Boyden chamber. Finally, r-viridistatin 2 effectively inhibited lung colonization of murine melanoma cells in BALB/c mice by 71%, suggesting that r-viridistatin 2 could be a potent anti-cancer agent in vivo