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Flow characterization at a turbulent tidal energy site in Minas Passage, Bay of Fundy
No full textCharacterization of site-specific hydrodynamic variables in an important factor in the successful design of tidal in-stream power systems. The Minas Passage, one of the Bay of Fundy's tidal channels, presents significant potential for tidal energy development because of its highly energetic flows. Flow in Minas Passage is highly turbulent (π
π β 1.4 Γ 10!). Although great strides have been made towards the complete characterization of the water column in Minas Passage and at similar sites in Nova Scotia, some aspects of the flow are yet to be explored in depth. This thesis uses observational data from five-beam Acoustic Doppler Current Profilers (ADCPs) to examine some of these aspects, namely (1) the vertical structure of the flow, (2) the turbulence characteristics at the site, and (3) the impacts of wind forcing on flow structure. Vertical profiles of along-stream velocity are fit using two methods: logarithmic law of the wall, and an adapted logarithmic law of the wall with a wake function. Fitting of the logarithmic law of the wall, a well-established method for estimating the mean velocity in a rough-walled turbulent boundary layer, results here in well-fitted estimations of the velocity profile near the seabed (π§ β€ 5π). Observational profiles are found to deviate from the fitted curves in the upper portion of the water column, measuring significantly faster flows than predicted by the logarithmic law. The adapted wake law model, which includes a cubic wake term to describe flow behaviour outside of the boundary layer, is found to result in much better fits throughout the entirety of the water column, with remarkably low error values across all flow speeds (ππ
πππΈ β€ 1%). Turbulence metrics including vertical beam amplitude (acoustic backscatter), variance in the vertical beam, and turbulent kinetic energy are examined and found to comply well with homogeneous isotropic turbulence theory and with observations at similar tidal sites. Vertical velocity spectra are also computed at varying depths below the free surface, and the presence of an inertial subrange complying with Kolmogorov theory is consistently noted in the absence of wind-generated surface gravity waves. Analysis of vertical structure and turbulence metrics is then repeated for periods of high wind. The parameters extracted from the logarithmic law and adapted model procedures during windy times do not differ significantly from those calculated for the mean flow conditions. Elevated vertical beam variance and TKE are, however, noted near the free-surface in the presence of wind. Spectral analysis shows consistent peaks in the mid-frequency range which coincide with short (5-8 s) waves when wind speeds surpass a threshold of approximately 10 π/π . This is of particular interest at the Minas Passage site because it presents a mechanism for validation of a network of X-Band marine radars at the site.</p
Does bilingualism enable the acquisition of multiple sensorimotor maps for speech?
No full textThis study examined the relationship between languages in the bilingual brain and the physical production of speech. The nature of language representations in the bilingual brain has been a decades-long debate, with some arguing for shared neural representations and others arguing for independent neural representations. The present study aims to provide further insight into this topic by investigating whether bilingualism enables individuals to acquire language-specific sensorimotor maps for speech production. To test this idea, a sensorimotor adaptation paradigm was used in which feedback of speech was altered in real-time to elicit sensorimotor learning. Thirty English-French bilinguals were assigned to one of two groups in a mixed design with Language (English, French) as the within-subjects variable and Group (1, 2) as the between-subjects variable. Following a period of unaltered speech, formants (vowel sound fundamental frequencies) were altered such that the vowel sounds participants heard themselves producing in English were in a different region of the vowel space (area defining different vowels in space based on the frequencies of their first and second formants) compared to the same vowel sounds
produced in French. Speech compensation in response to altered feedback was calculated and aftereffects associated with compensation were examined as the main variables of interest. It was demonstrated that, for the same vowel sounds, bilinguals were able to acquire and maintain two distinct sensorimotor speech patterns of equal magnitude but opposite direction: one in French and one in English. Additionally, significant aftereffects following the removal of manipulation were observed. These results provide evidence for the presence of language-specific and dissociable sensorimotor maps for speech in the bilingual brain
An investigation of local zeta functions of self-similar fractal strings
No full textWe give an overview of fractal strings and examine the relationship between theirMinkowski dimension/content to their complex dimensions and their geometric zeta functions with the aim of demonstrating the geometric information made available by studying these entities. Building on this knowledge, we propose a way of searching for locally defined geometric zeta functions by looking at simple examples of self-similar fractal strings
Analysis and prediction of computer industry talent demand based on machine learning
No full textFrom the perspective of enterprise and social demand, this research analyzes the characteristics of talent demand in Canadian computer industries by using big data thinking, text analysis and machine learning. Firstly, through crawler technology, we obtained the recruitment information on mainstream Recruitment websites in Canada and developed a standardized collection process. After processing the data, we used IBM Watson Studio to split the text and constructed the skill keyword dictionary to extract the talent demand. In addition, the time series algorithm was used to predict the changes of the computer skill keyword over time and visualize the results. After analyzing the experiment results, it is found that computer science related jobs are changing over time and require new skills to adapt. Finally, based on the analysis results, suggestions and plans for cultivating talents related to computer science are proposed from the perspectives of enterprises, governments and campuses. The governments should pay attention to policy making, campuses and enterprises should strengthen cooperation and create a new talent training model
Predicting major donor prospects using machine learning
No full textAn important concern for many not-for-profits is their major gift fundraising.Major gifts are large gifts (typically 10,000 or more. We also experimented with using only donation and behavioural data, which saw increase in false positive values than false negatives for most of the charities. Furthermore, we forecast how much money major donor constituents will contribute to the charity, in which Light GBM regression model was performing well with lowest RMSE values and standard deviations
DNA barcoding of the maritime shrew, Sorex maritimensis Smith: using DNA sequence of the cytochrome oxidase subunit 1 gene in taxonomic and field studies of a Canadian endemic mammal.
No full textIn 2002, the maritime shrew was elevated from a subspecies, Sorex arcticus maritimensis, to a distinct species, Sorex maritimensis Smith, based on sequence divergence for the mitochondrial cytochrome b gene. The maritime shrew is a Canadian endemic found only in Nova Scotia and New Brunswick. It has been identified as one of the most susceptible vertebrate species in Nova Scotia to the effects of global warming.
The first part of this thesis tests the hypothesis that Sorex maritimensis is a distinct species by employing DNA barcoding theory and cytochrome oxidase subunit 1 (cox1) gene sequences. A variety of tree- and distance-based approaches are used including recently developed methods to delineate species from DNA sequence data such as the Poisson Tree Processes (PTP) method, the Automatic Barcode Gap Discovery (ABGD) method, the Assemble Species by Automatic Partitioning (ASAP) method, the General Mixed Yule Coalescent (GMYC) method, as well as multi-rate Poisson Tree Processes (mPTP), and Bayesian Poisson Tree Processes (bPTP). All analyses except mPTP and bPTP support the hypothesis that S. maritimensis is a distinct species. In addition, the rate of divergence for cox1 vs. cyt b was examined for eleven species of Sorex shrews which showed an atypically low rate of divergence for the cox1 gene between S. maritimensis and S. arcticus.
The second part of this thesis is an optimization of a non-invasive method to identify shrew species from fecal samples using shrew-specific primers to amplify a short, ~120 base pair section of the cox1 gene. This approach uses feeding tubes baited with dead insect larvae to collect shrew feces, which are a source of DNA for species identification. This technique holds promise for more precisely mapping the distribution of this relatively rare shrew in Nova Scotia and surrounding regions
The moderation of embodied attachment on the relationship between visual-temperature cues and prosocial behavioural intentions
No full textTwo studies sought to examine the impact of visual-temperature cues on prosocial behavioural intentions, and if these relationships would be moderated by recollected memories of caregiver sensitivity. The hypotheses and method for both studies were identical. Hypothesis 1 anticipated that individuals would show more prosocial intentions when asked to consider a friend (vs. a stranger). Hypothesis 2 expected overall that as recollected caregiver sensitivity increased, prosocial intentions would increase. This main effect of caregiver sensitivity was anticipated to be qualified by an interaction in which prosocial intentions among participants who were high (but not low) on caregiver sensitivity would be higher in the cold (vs. warm) condition while it was expected that prosocial intentions among participants who were low (but not high) on caregiver sensitivity would be higher in the warm (vs. cold) condition. Participants completed a self-report measure of recollected memories of caregiver sensitivity, and a self-report romantic attachment measure (used for exploratory analyses). Participants were then assigned randomly to view either warm or cold stimuli (images in Study 1, anagrams in Study 2), and then rate their prosocial intentions to both a friend and to a stranger. In Study 1, Hypothesis 1 was not supported. Hypothesis 2 was partially supported in that there was a significant main effect of caregiver sensitivity, such that as caregiver sensitivity increased, prosocial intentions increased. Hypotheses for Study 2 were not supported. Notable exploratory analyses in Study 1 found a marginal three-way interaction in which it was observed that securely attached individuals showed more prosocial intentions in the cold (vs. warm) condition, while insecurely attached individuals showed more prosocial intentions in the warm (vs. cold) condition
The duty to accommodate: an exploratory study of where the threshold of undue hardship exists
No full textIn the employment context, it is understood that employers have a duty to accommodate their employees to the point of undue hardship; however, its extent is difficult to define. This thesis examines 15 accommodation cases to determine where the threshold of an employer's duty to accommodate exists. Qualitative content analysis was used alongside grounded theory to assess and compare the cases selected for study. Additionally, an intentional coding scheme was used to code and categorize the data found within the cases. This was done based on the language and reasoning that the Justices used in their proceedings. It was found that the previous factors and notions surrounding the duty to accommodate were upheld and reaffirmed by the Justices. The assessment of the cases also revealed additional and novel factors that may need to be considered when accommodating employees. From this research, a greater understanding is afforded to employers in terms of when their duty to accommodate has been discharged and what factors may be assessed as a result
Mercury bioaccumulation in mussels in the Minas Basin: a comparison of soft tissues and shells as bioindicators
No full textThis project investigated mercury contamination in coastal mussels at the Minas Basin, Bay of Fundy. This research aims to evaluate whether mussels are a valid and reliable biomarker of coastal mercury pollution. There was low contamination at the sampling sites (mean sediment total mercury = 5.1 ng/g dry weight (d.w.)). The mean concentration of total mercury in the mussel tissues was 62.3 ng/g d.w. (SD = 13.7 ng/g d.w.; n = 57). Through a regression analysis, we determined that total mercury and methylmercury in tissues were significantly negatively related with the mussel's condition index (p < 0.001, R = -0.5, R2 = 0.24 in both cases). Additionally, we found a negative and significant linear relationship between the logarithm of the whole organism soft tissue mass (d.w.) and the logarithm of the total mercury content (p < 0.001; R2 = 0.23) Through a Pearson correlation, shell length was found to have a negative correlation with the total mercury in soft tissue samples (p value = 0.01, R = -0.3). The mean concentration of methylmercury in soft tissues was 13.2 ng/g d.w. (SD = 6.3 ng/g d.w.), equivalent to 1.7 ng/g wet weight (w.w.). This is lower than Environment Canada's tissue residue guideline for effects on aquatic organisms for methylmercury (33 ng/g w.w.) In the mussel shells, total mercury in all samples was below the method detection limit (MDL = 1.7 ng/g d.w.). As such, for this study, the shells could not be used as a bioindicator of soft tissue concentration of mercury
Bioaccumulation of methylmercury in a wetland impacted by herring gull guano and water table restoration on Brier Island, Nova Scotia
No full textMercury is a toxic environmental contaminant that is known to undergo long range transport, resulting in deposition in remote and pristine ecosystems. High concentrations of mercury in low trophic levels results in a high capacity for trophic transfer up the food web. As a result, low trophic level invertebrates may be used as sentinels for ecosystem contaminate concentrations and overall ecosystem health. Big Meadow Bog, located on Brier Island, Nova Scotia, is a disturbed wetland habitat that was subject to water table restoration and colonization by herring gulls (Larus argentatus), resulting in significant nutrient input from guano.
Invertebrates encompassing 25 aquatic and terrestrial families were sampled from Big Meadow Bog in addition to surface water. Methylmercury (MeHg) was analyzed in all samples using gas chromatography-atomic fluorescence spectroscopy (AFS). Methylmercury concentrations were significantly different across invertebrate families, and functional feeding groups (FFG). Concentrations of MeHg in Big Meadow Bog were on average 1.61 times higher than MeHg concentrations observed at undisturbed sites. More research into the role of nutrients on MeHg bioaccumulation at the base of food webs is required to better understand the factors affecting trophic transfer of contaminants in Big Meadow Bog