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Testing the energy resolution capabilities of the Compton And Two Photons Spectrometer
Full text linkThe nuclear equation of state describes the properties and formation of large astrophysical objects, notably neutron stars. It can be constrained with the density dependence of the symmetry energy, which is modelled to have a linear correlation with neutron skin thickness. Neutron skin thickness can be studied with parity-violating electron scattering experiments, which have a systematic error that can be constrained by measuring beam-normal single-spin asymmetries. Experimental measurements of such asymmetries agree with theoretical values, but the theoretical values have an error of 20% due to a poorly known Compton form factor, which is a function of the energy deposited into the target in elastic Compton scattering. Because of this, it is necessary to separate elastic and inelastic Compton scattering events. CATSis alarge NaI(Tl) scintillating detector that will be used to study the Compton form factor at the A2 Collaboration in Mainz, Germany. Two Geant4 simulations of CATS were built, and using results from Ref. [Wis94], efficiency and contamination were calculated for a range of energies with one of these simulations. This was done by estimating the ratio of elastic to inelastic photons produced at a variety of energies for Compton scattering off of a 12C target. Then, based on the estimated ratio, photons at energies associated with elastic and inelastic Compton scattering off of a 12C target were fired into the core of the CATS simulation. Additionally, CATS was used for the first time in years to collect cosmic ray data for an overnight run in Mainz in July of 2022 for testing purposes
Examining Environmental Effects on the Colonization of Dark Septate Endophytes in Spartina alterniflora and S. patens
Full text linkUsing multi-proxy measures of lake sediments to identify environmental changes in protected watersheds of British Columbia, Canada
Full text linkPaleolimnology uses lake sediments to recognize environmental trends through time. This is useful in watersheds with a knowledge gap of historical environmental conditions or missing perspectives of long-term ecosystem responses. Cameron Lake sediments were used to identify historical trends of Didymosphenia geminata valves in a mat-prone watershed. The lake core represented approximately 600 years of sediment accumulation and findings demonstrated that D. geminata was a historical member of the riverine diatom community. Though in low abundance in older sediment, valve concentrations increased in the early 1900s and peaked at ~1990s, coinciding with observations of mats. Geochemical proxy measures were then analyzed to explore if watershed disturbance was a driver of environmental conditions favouring D. geminata mat formation. No clear geochemical trends were identified, thus watershed disturbance was not associated with D. geminata proliferation in the ~600 year record. Cultus Lake has experienced urbanization, resulting in cultural eutrophication. Over the past century, water quality metrics suggested a decline in hypolimnetic oxygen, however there is a lack of temporal knowledge on the biological responses to eutrophication. Cultus Lake sediments were analyzed for temporal trends in benthic invertebrate assemblages. Chironomid assemblages shifted from taxa associated with oligotrophic, high oxygen conditions to an assemblage indicative of low oxygen conditions. This shift began in the 1920s, coinciding with forestry and agricultural activities. A recent assemblage shift in the 1970s indicated that the assemblage is now dominated by generalist taxa. Findings suggest the benthic environment of Cultus Lake has less oxygen availability in recent decades. This temporal information can be used in future lake management and recovery plans for species of concern at Cultus Lake
Creating a ‘New’ New Brunswick: A Critical Analysis of New Brunswick’s Population Growth Strategy Through Economic Immigration Policies
Full text linkNew Brunswick has been faces with a variety of social and economic struggles in recent
years, and as a result has been exploring a variety of different solutions to resist these shortfalls.
Population growth remains a significant focus for the province to accommodate for many of these
issues, predominantly through immigration; the underlying effects and indirect consequences of
these strategies remain unresearched. This thesis thus consists of a critical analysis of three
documents using a Bourdieusian theoretical framework: the New Brunswick Population Growth
Strategy (2019-2024), the New Brunswick Express Entry Stream, and the New Brunswick Skilled
Worker Stream, to see how well these programs align with what is offered by the New Brunswick
government for supports and consider if or how these programs encourage retention in the
province. Findings indicate an indirectly exclusive economic immigrant that adheres to a variety
of neoliberal principles, and simultaneously enforce patriarchal, geopolitical, and racial hierarchies
through many of these credentials. Findings also indicate a privatized, economically driven, and
short-term model of immigration and population growth, that lacks consideration of the long
researched barriers to successful integration within communities. Lastly, the province utilizes the
existing inequities within economic immigration programs to promote short-term contributions to
the province’s economy without equal support that citizens and Permv anent Residents may access.
This thesis concludes with reflections on how to improve these strategies with a long-term
approach to population growth and retentio
Legacy contaminants in brook trout from remote New Brunswick lakes
Full text linkDichlorodiphenyltrichloroethane (DDT) and mercury are legacy contaminants that are persistent in the environment for decades or longer. They may impact food webs through bioaccumulation, biomagnification, and chronic toxic effects in exposed biota. DDT was applied aerially on large scales to the conifer forests in north-central New Brunswick between 1952 and 1968 for pest control. I sampled seven lakes in the summers of 2020 and 2021 to investigate the impact of historical DDTs on the present day aquatic environment. I sampled brook trout, aquatic invertebrates, zooplankton, and lake surface sediments. I found DDTs were up to ~14 times higher in brook trout muscle tissues from lakes where DDTs were applied to the watershed compared to reference lakes. DDTs in brook trout exceeded CCME guidelines by up to ~22 times. Mercury is a common contaminant of concern and delivered to lakes by atmospheric transport. Most mercury originates from anthropogenic activities, including burning fossil fuels, and mining or smelting metals rather than natural geogenic sources. I sampled brook trout from seven New Brunswick lakes in 2020, and found mercury levels comparable to similar studies in eastern North America. Mercury in brook trout exceeded CCME guidelines for methylmercury by up to ~12 times. Using DDT and mercury measures, we can further our understanding of legacy contaminants in lakes of New Brunswick, Canada
The effect of a taurine deficiency on the cardiovascular response of brook char (Salvelinus fontinalis) to hypoxia
Full text linkTaurine is a non-proteogenic β-amino acid found in relatively high abundance within the heart of freshwater teleosts. By exhibiting cardioprotective properties through participation in osmoregulation and calcium (Ca2+) homeostasis, taurine has been linked to supporting the cardiovascular physiology under environmental hypoxia. The functional capacity of the heart is defined by cardiac output (Q ), representing the product of heart rate (fh) and stroke volume (SV). A taurine deficiency has been shown to impair the ability to increase SV under hypoxia in vitro and cause a shorter time to loss of equilibrium (LOE) in vivo, indicating cardiovascular disturbances. The knowledge gap addressed in this study is the effect of a taurine deficiency on all three cardiac parameters in vivo under hypoxia. These measurements were paired with metrics of the O2 carrying capacity of the blood and osmotic stress following acute hypoxia and recovery. Brook char (Salvelinus fontinalis) were used as a representative freshwater teleost, for this analysis. A taurine-deficient (TD) model was achieved through 5% dietary β-alanine supplementation, a known competitive inhibitor of taurine transport. fh, SV, and Q in vivo were quantified using electrocardiograms (ECG) and ultrasonic flows. Significance was found in lower resting fh and blunted bradycardia in TD fish. SV was maintained at similar levels to control fish, although TD fish did not elevate SV under hypoxia, likely tied to their lesser bradycardia. Q was similar in both models, along with hematological parameters characterizing the capacity to transport O2 in circulation. TD hearts had decreased lactate levels, an important metabolite to cardiovascular function under a hypoxia stressor. The main finding of this study is that TD fish have a greater sensitivity to environmental hypoxia, attributed to just a 21% reduction in cardiac taurine. With the typical increase in SV seen under hypoxia attributed to a lower fh, regulatory disruption of contractile frequency may explain the observed physiological differences. As an important mechanism to mitigate osmotic disturbances under hypoxia, a limited ability to perform taurine efflux may be the underlying cause of cardiac dysfunction. This may additionally lead to alterations to the Ca2+current (ICa) acting on the heart's pacemaker or autonomic nervous system activation. With the progression of global warming and v associated disturbances to aquatic O2 availability, ensuring sufficient taurine in the diets of freshwater fish could be a method of supporting cardiovascular function
Predictors of undergraduates’ psychological well-being: Social support stability, campus resource stability, and locus of control
Full text linkThe purpose of the present study was to investigate social and campus resources as predictors of students’ psychological well-being, with locus of control (LOC) as a potential mediator. The study consisted of 138 participants who were enrolled in an Introductory Psychology course, and the students completed an online questionnaire with an incentive of 1 course credit as compensation for participating in the study.
Findings demonstrated that perceived stability of resources added additional variance in students’ psychological well-being, suggesting that the stability of resources should be considered in addition to the availability of resources when assessing students’
psychological well-being. Results demonstrated that perceived campus support also accounted for additional variance in students’ psychological well-being, and therefore should be considered alongside perceived social support when investigating support systems and students’ well-being. Individual measures of perceived support did not predict LOC, nor did LOC serve as a significant mediator in the relationship between perceived support and psychological well-being. Using the findings of the present study as the foundation for future research, as well as resource organization and prioritization, it is possible to further the general understanding of students’ support needs while helping to ensure a positive university experience both academically and socially
Academic Misconduct: An Educational Consequence of Psychopathy
Full text linkAcademic misconduct has long been an issue plaguing academic institutions. The trait
of psychopathy has remained consistently linked to academic misconduct; however, the
influences underlying this relationship are not well known. Therefore, the current study
aimed to first replicate a past study that showed a facet of academic entitlement to
mediate this relationship. In addition, it aimed to contribute to the literature by
investigating academic motivations (extrinsic, intrinsic, amotivation) as additional
mediator variables between psychopathy and academic misconduct. One hundred and
sixty undergraduate students completed a survey measuring psychopathy, academic
entitlements, academic motivations and academic misconduct. Psychopathy
significantly predicted academic misconduct; however, neither facet of academic
entitlement mediated this relationship, nor did any of the motivational variables.
Overall, although psychopathy remains highly predictive of academic misconduct, the
lack of influence of the other variables may suggests that academic misconduct, as well
as the beliefs and culture surrounding it, have shifted within the campus community