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Distribution of suspected microplastics within surface waters of two New Brunswick rivers
Get PDFMicroplastics (MPs) are pervasive contaminants in aquatic environments; however, little is known about their distribution and impacts in freshwaters. This study examines the distribution and abundance of suspected microplastics in surface water samples from two rivers in rural watersheds of New Brunswick, Canada. Both rivers are subject to point sources of microplastic input from wastewater treatment plants (WWTPs), as well as diffuse inputs from the atmosphere, surface-water runoff, and human activities. The Kennebecasis is more developed than the Nashwaak, with a greater number of WWTPs and increased human activities. Surface water samples from the rivers were collected at sites upstream and downstream of WWTP effluent discharge points and at intermediate sites spaced evenly along the river stretches sampled. Suspected MPs were present at all sites and 72% were blue-coloured fibres. Surface water samples from the Kennebecasis contained a greater abundance of suspected MPs compared to those from the Nashwaak (p = 0.03). Suspected MP abundance was significantly higher downstream of four WWTPs compared to upstream (p = 0.03) and intermediate sites (p = 0.02). Results help understand the input, transport, and fate of MPs in rivers from watersheds with low population density. These findings are an important first step in establishing the scope of MP contamination within freshwaters from Atlantic Canada
Examining the role of negative pre- and post-goal emotions on susceptibility to misinformation for central and peripheral details
Get PDFThe current study examined how the narrowing of cognitive scope due to negative pregoal emotions and the broadening of cognitive scope due to negative post-goal emotions influences susceptibility to misinformation. The pre-goal emotion studied was threat, and the post-goal emotion studied was sadness. Participants included 91 young adults (M = 19.01 years, SD = 2.09 years) who viewed threatening, sad, and neutral images, then were exposed to misinformation on a memory test. Participants veridical memory and acceptance of misinformation was assessed through a second memory test. A significant misinformation effect was found across conditions. However, there were no differences between threat and sadness images for peripheral misinformation acceptance. As well, across the threat, sadness, and neutral images there were no differences in veridical memory, implying that no narrowing or broadening of cognitive scope occurred. From this, it was concluded that pre- and post-goal negative emotions may not have the expected narrowing and broadening effect on cognitive scope
Mature versus traditional students : Does manipulating self-efficacy influence performance?
Get PDFA debate exists in the literature as to whether mature students fare better than traditional students in university. Research suggests an advantage for mature students, but the reason for this finding remains uncertain. Emotional regulation has been shown to increase with age. High self-efficacy is one of the strongest predictors of academic success and has been successfully manipulated in previous research. This study hypothesized that mature students would display higher emotional regulation and self-efficacy compared to traditional students and that higher emotional regulation would shield against attempts to
lower self-efficacy. Twenty-four participants from a small Canadian university completed both an online survey and an experimental manipulation of self-efficacy. Half of the participants received false negative feedback and the other half received false neutral feedback. The experiment failed to manipulate self-efficacy and no significant differences were found between mature and traditional students; thus, all hypotheses were refuted. Suggestions for future research are discussed including limitations and procedure changes
Molecular testing of Lyme disease
Get PDFLyme disease is a tick-vectored multisystemic illness caused by the bacteria Borrelia burgdorferi sensu lato contracted throughout North America and Eurasia. Although Lyme disease is the most common tick vectored illness in North America, many questions about the disease such as pathophysiology and organ involvement remained unresolved. Additionally, persistence of the Borrelia bacteria after antibiotic treatment is controversial and the role of antibiotic tolerant bacteria in causing chronic Lyme disease symptoms is even less well understood. The reliance on serological testing in Lyme disease leaves many questions unanswered and accurate diagnosis of Lyme disease in certain situations is challenging. To address some of these outstanding questions, direct detection of Borrelia from biopsy and autopsy tissue and culturing of Borrelia from patients showing persistent Lyme disease symptoms can be valuable. In this study, I investigated autopsy tissues using the DNA-based detection methods of nested PCR and Fluorescent in situ hybridization (FISH) and the protein-based technique of immunohistology from seropositive, seronegative, and serologically untested individuals. This study showed that Borrelia was widely distributed in different organs in both seropositive and seronegative participants. These techniques were then extended to biopsy tissue samples. My findings showed that B. burgdorferi is pleiomorphic, with FISH and immunohistology showing predominantly round body and biofilm forms with fewer in the spirochetal form. Finally, I showed that culture of viable Borrelia is possible from different body fluids from participants with persistent Lyme disease symptoms. This finding strengthens the evidence that chronic Lyme disease is associated with an active and long-standing Borrelia infection. Findings from this study could be extended to investigation of other tick-vectored diseases and reinforce the potential for the use of direct molecular methods in disease diagnosis
How do floral changes affect the pollination ecology of Halenia deflexa
Get PDFSpurred gentian (Halenia deflexa) is named after the nectar spurs (i.e. nectar-storing appendages) that adorn its flowers. Nectar spurs generally affect the mechanical fit between
plants and their pollinators because they restrict nectar access to animals with long-tongues or strong mouth parts. Nectar spurs are therefore an important floral trait that can shape species’ pollination ecology. Halenia deflexa’s pollination ecology, however, has not been documented and it is unclear whether the species has any insect pollinators at all. I aimed to determine the principal pollinators of H. deflexa. During summer 2019, I observed patches of H. deflexa for ~40 hours total to document visitation by pollinators. I found the species to be visited almost exclusively by bumblebees (Bombus sp.), including the endangered B. terricola (yellow banded bumblebee). The likelihood of visitation by Bombus sp. decreased every day before coming to a complete stop after August 7. I found that the total amount of time that a Bombus visitor spent foraging from a single plant, per patch, increased with the number of open flowers on a plant. Throughout the summer, I also noticed that spur length of H. deflexa decreased from the first and last flowers on a plant and I quantified this change in 16 marked individuals. Last, I found that reductions in spur length coincided with reductions in visitation by bumblebees. This work does
not determine whether changes in pollinator behavior are influenced by spur length. It does, however, feature some novel observations of H. deflexa and demonstrate the importance of flower shape in a plant–pollinator system
Charged and neutral Au nanoparticles interact differently with Langmuir film-based synthetic membranes: Implications for nanoparticle uptake and membrane protein activity.
Get PDFA Langmuir-film based synthetic membrane system containing an active transmembrane protein, glucose- 6-phosphatase (G6Pase) was employed to investigate the effects nanoparticle exposure as a function of membrane surface pressure. The activity of G6Pase after exposure to 5 nm gold nanoparticles functionalized with anionic, cationic, and neutral ligand coatings was found to increase by as much as 300% for both anionic and neutral particles at surface pressures less than 30 mN/m, indicating significant nanoparticle-protein interactions. Atomic force microscopy imaging was used to track the distribution of nanoparticles and G6Pase within the membranes and correlate changes in activity to the distribution of G6Pase in the membrane. Conditions which enabled the redistribution of protein in the form of solubilization or aggregation within the membrane were identified for each class of nanoparticles. This investigation demonstrates the importance of the phospholipid environment surrounding membrane proteins during exposure to nanoparticles which can impact the nanoparticle fate in terms of uptake as well as potential effects on membrane protein activity.This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Nano Materials, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsanm.0c0190
Operant wheel running by rats on fixed ratio schedules of sucrose reinforcement
Get PDFPrior studies have shown that operant wheel running in rats is reinforced by sucrose on fixed ratio (FR) schedules, but wheel running also occurs at a high frequency without experimentally-arranged consequences. Findings that scheduled reinforcement exerts only limited control on operant wheel running served as the basis for the current study. Eight female Long-Evans rats were exposed to a series of FR schedules (FR 5, 15, 40, and 80) for 0.1 ml of 20% sucrose solution and again with 0% sucrose (water). Wheel revolutions at each ratio size produced outcomes (sucrose or water), and wheel running rates were assessed for each scheduled reinforcement rate (FR size). Results showed significantly higher wheel-running rates for sucrose reinforcement than water; however, the difference in rates by outcome was modest and independent of the control exerted by FR size alone. For both outcomes, wheel-running rates decreased, and latency to initiate running increased as FR size increased and the reinforcement rate decreased. The lack of variation in the reinforcing effect of sucrose as the FR size varied differs from findings with operant behaviours such as key pecking and lever pressing. This finding suggests that automatic reinforcement and constraint on the opportunity to run might help explain these differences, but further research is required to substantiate these findings
Synthesis and characterization of heteroleptic redox active bismuth dithiolene and dithiolate complexes
Get PDFThe “twelve principles of Green Chemistry” marked an important transition in the chemical industry’s view on waste - moving away from a waste management approach, and towards a waste reduction and prevention approach. The use of catalytic reagents in place of traditional stoichiometric ones is an important aspect of reducing the amount of waste generated during reactions. Transition metal complexes frequently used in redox catalysis, however, feature toxic metal centers which can be harmful to both human health and the environment. Bismuth has recently been the subject of interest as an alternative to toxic transition metal catalysts as redox non-innocent ligands can be used to make the otherwise redox inactive metal, redox active. The current study focuses on the use of dithiolenes and dithiolates as redox non-innocent ligands to impart redox activity on a heteroleptic bismuth complex. Two bismuth complexes, (Mes2Bi)2(tdt) and BiCl(tdt)-Py2, were synthesized and characterized by 1H and 13C{1H} NMR spectroscopy and X-ray crystallography
The geography of public space in Sackville
Get PDFSackville is in a unique position in that much of the town relies on Mount Allison University, which is located in the centre of town. Because of the location of the university, much of the central area of town acts as an extension of the campus for students. However, this relationship often seems to be one-way. Residents of town who are not employed by the university do not seem to make use of the campus in the same way students make use of town. Similarly, there are many public spaces in Sackville that residents frequent but students rarely go to. This research will look at a number of public spaces in Sackville, as well as a few buildings on the Mount Allison University that are open to the public and are sometimes treated as public spaces. Discussion will focus on concerns over accessibility as well as the development of space that can better serve the diverse needs of the community of Sackville, residents and students
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Impacts of legacy contaminants from historic gold mining on lakes in Dartmouth, Nova Scotia
Get PDFHistoric gold mining activities in Nova Scotia (Canada) occurred prior to modern waste
management practices and contaminants were released into the environment. One notable
example is the Montague Gold Mine which operated from 1863–1940. Although environmental
monitoring data are sparse, nearby freshwaters likely received contaminants from past mining
activities through inputs from surface waters and the atmosphere. To investigate the long-term
effects of historic gold mining practices on lake ecosystems, I examined zooplankton remains
and sediment geochemistry archived in dated sediment cores from impacted (Lake Charles) and
reference (Loon Lake) lakes. Sedimentary concentrations of arsenic (As) were used to infer past
mining activities. Sedimentary chlorophyll-a concentrations were used as a proxy of trends in
lake primary production. Cladoceran assemblages of both lakes were significantly different (p <
0.05) during the time period of mining, compared to pre- and post-mining periods. Geochemical
and zooplankton changes were most extreme in Lake Charles, which recorded levels of As
contamination that exceeded sediment guidelines by, on average, 300 times since gold mining
began. Despite the Montague Gold Mine closing 80 years ago, modern bioindicator and
geochemical measures differ from the pre-mining periods, suggesting that past mining activities
and likely also recent anthropogenic stressors, have impacted lake ecosystems