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From form to flow: reconstructing the life posture and hydrodynamics of iconic Ediacaran taxa
No full textThe Ediacaran successions of Newfoundland include some of the oldest macroscopic
candidate metazoans. These fossils are preserved as two-dimensional near-census assemblages on
deep-marine volcaniclastic sediments beneath tuffites. The communities, dominated by the frondose morphogroups Rangeomorpha and Arboreomorpha, were traditionally interpreted as
consisting primarily of erect taxa that had been felled and aligned by paleocurrents, alongside some randomly oriented reclining forms. However, in the absence of sedimentological evidence,
paleocurrent direction has been inferred from fossil orientation, despite the unresolved posture of
many of these organisms in life.
This PhD focuses on the Melrose Surface near the Catalina Dome of the Discovery
UNESCO Global Geopark, which provides sedimentological evidence for current direction in the form of current ripples and cross-lamination. This site offers a unique opportunity to reconstruct the life position and orientation of Ediacaran taxa relative to sedimentologically-determined
paleocurrents. An integrative approach has been employed herein, combining different strategies detailed in three papers:
1. Taphonomic reinterpretation of the genus Charniodiscus: by examining the taphonomic clues of the type material C. concentricus, this taxon was reconstructed as a conical bifoliate erect/recumbent frond, distinguishing it from reclining arboreomorphs such as C. procerus
(present in the surface), which shows consistently extraordinary stem preservation across stratigraphic units.
2. Clustering algorithms on Fractofusus misrai orientations: using novel statistics based on
modified polythetic and monothetic clustering techniques adapted to circular variables,
preferential orientation trends oblique to the paleocurrent were identified in the population of
F. misrai from the Melrose Surface.
3. Computational Fluid Dynamics (CFD) over Fractofusus misrai: turbulent flows were modeled
to understand the hydrodynamic phenomena associated with highly detailed reconstructions F.
misrai. The preferential orientations found on the Melrose Surface result from a balance between maximizing aspect ratio for feeding efficiency and reducing current-induced drag.
This work presents an integrative approach based on taphonomy, statistics, and CFD to
reconstruct the position of Ediacaran taxa and the currents they lived in. The papers challenge the assumed erect position for all arboreomorphs and the random orientation for reclining
rangeomorph taxa. This thesis advocates for interpreting fossils as reclining flat, responding
rheotropically to paleocurrents, unless evidence supports otherwise.Includes bibliographical reference
Evaluating the efficacy of digital language learning tools in enhancing bilingual education in small community schools of the western north region, Ghana
No full textBilingual education programs are gaining global traction, promoting language diversity and equitable access for minority students. However, only 25% of countries have improved their bilingual education efforts. The study assesses the efficacy of digital language learning tools in enhancing bilingual education in small community schools of the western north region of Ghana. The study used an interview guide to collect data from four principals, eight teachers, and four parents from four schools. Thematic analysis was used to analyse the interview data: Effectiveness of bilingual language education interventions, effects of digital language learning tools on bilingual educational outcomes in small community schools, and to assess the challenges and barriers associated with the effective implementation of digital language learning tools in small community schools in the Western North Region, Ghana. Results showed that digital learning tools enhance students' fluency, bilingual proficiency, and cognitive development. Also, it was revealed that technical issues, pedagogical barriers, and access and equity were challenges of digital learning tools from an administrative perspective. Teachers also affirm internet connectivity challenges with a lack of technical support. Parents revealed an increase in educational expenses. Therefore, the study concludes that, although bilingual language learning in the Western North Region of Ghana is more effective, it is associated with technical challenges and increased educational expenditure. On this account, the study recommends that policymakers allocate funds for the region's technical challenges, and principals must partner with local organizations to support modern digital learning tools to complement the current ones
Two-factor authentication in VR using near-range extended reality and smartphones
No full textModern smartphones have a wide variety of authentication and authorization measures: from drawing a simple pattern to a fingerprint scan system. However, the whole “password” is always contained inside of the device’s memory. In case of information leak, the possible malefactor/attacker has access to the whole password, therefore information security is at risk. Enhancing security measures is essential to develop a robust tool that ensures the safety of both head-mounted devices and smartphones. Users wearing headsets are vulnerable to real-world security threats, such as unauthorized individuals attempting to access their personal information or belongings. Furthermore, the necessity of removing the headset to interact with the smartphone can lead to potential security breaches. Thus, it is crucial to address these vulnerabilities to protect users effectively, both in VR and the immediate environment.
This thesis proposes a novel approach to two-step authentication by “splitting” the password authentication process between two independent devices. In this method, one half of the password is displayed on a smartphone screen, while the other half is delivered through a head-mounted device (HMD). This design ensures that only an individual with access to both devices can successfully combine the two halves to form the complete password. The research suggests that this dual-authentication measure could effectively enhance security in systems that utilize both HMDs and smartphones simultaneously.
A prototype was developed and tested, enabling users to interact with their smartphone content in a virtual reality (VR) environment. This system facilitates authentication through various challenges, such as CAPTCHA, numeric passwords, or game-like interfaces, requiring users to input specific passwords. Success in these tasks hinges on the effective communication and combination of inputs from both the HMD and smartphone, making it impossible to bypass the authentication process without both devices.
The findings of this research are supported by two publications detailing the experiments and user studies conducted on the password-splitting method and the integration of smartphone content into the VR setting.Includes bibliographical references (pages 87-100
The development of prosodic structure by Persian first language learners: a longitudinal, comparative study
No full textThis dissertation investigates the prosodic development of three Persian-learning children following a longitudinal study design. The study pursues two key objectives. First, we aim at documenting early patterns of phonological development in Persian. Second, we analyze these patterns through current models of phonology and phonological development. Our findings reveal a systematic trajectory in phonological acquisition. Children first acquire singleton onsets and codas, followed by coda-onset clusters, with morpheme-final clusters emerging last. We also observe that post-vocalic consonants and consonant clusters exhibit similar phonotactic behaviour in both medial and final positions.
To account for these patterns, we engage with Piggott's (1999) proposal on syllabification at word boundaries and Rose's (2003) developmental interpretation of this proposal. Piggott suggests that final consonants may be analyzed either as true codas in languages with restricted phonotactics, or as onsets of empty-headed syllables in languages with fewer phonotactic restrictions in this position. Rose extends this proposal to child phonological development, suggesting that learners assign final consonants to different prosodic positions based on phonotactic restrictions.
Our analysis challenges these proposals, yet remain compatible with Piggott's original intuition that prosodic structure reflects distributional constraints on speech sounds within individual languages, rather than completely universal rules of syllabification. This suggests that prosodic acquisition is language-specific and guided by the input available to the learner.
Overall, this study contributes to existing phonological models. By shifting the focus from completely universal views of acquisition to a more language-specific approach, this study offers a more nuanced understanding of phonological acquisition across languages
Autonomous women: an examination of the lives and experiences of childfree, never-married single women of color from a decolonial feminist perspective
No full textThe number of childfree and never-married women continues to increase globally. However, we know very little about their subjective experiences and identities outside of the traditional heteronormative frameworks, and we know even less about women of color (WOC) outside of these contexts. The discourse of patriarchy is often limited to white women’s experiences and perceptions. Viewing the oppression of women through the prism of patriarchy only does not allow for the understanding of the differences between white women and women of color (WOC). My study examines how childfree, never-married single WOC have created a separate space for themselves as a challenge to the paradigms of patriarchy and colonization. The experiences of WOC are uniquely situated due to the intersection of colonialism, sexism, and racism.
My research applies the theoretical frameworks of Feminist Standpoint Theory and Decolonial Feminism through an intersectional lens to examine the social, economic, and cultural contexts that shape the identities of childfree, never-married single WOC in the United States. I answer the question - how do childfree, never-married single WOC experience and feel about romantic love, singleness, sex, and attachments in society? I interviewed forty women of color using a qualitative, inductive inquiry approach. The women in my study are aware of the history of oppression associated with heteronormative marriage within a colonial context.
My findings include that childfree, never-married single women of color (WOC) have rejected cultural expectations and constructed their own boundaries; they do not ascribe to the traditional heteronormative gender roles, heterosexual marriage and conventional motherhood; they use education as an essential aspect of their path toward independence and
unconventionality and their family histories shape their decisions about work and financial stability; they successfully operate through some colonial institutions while circumventing others; they do not center romantic love in their lives; and they receive very little support from social institutions, which creates more precarity for them in a society that centers whiteness, capitalism, and normative heterosexuality.
I have created new terminology (Autonomous WOC) to discuss and explain how these women live a life contradictory to cultural norms and create their own norms based on what is important to them. They live a life of independence and freedom from social and cultural limitations. I argue that childfree, never-married single WOC have collective experience and knowledge that is rooted in group identity situated in a common history and shared social oppression. These women have a distinct standpoint, and their narratives could provide pertinent information to the variances and cultural shifts in gender norms, patriarchy, capitalism, and heterogender family structures in American society.Includes bibliographical references (pages 234-244
Unlocking the narrative of grief and hope in international students in the Faculty of Education, MUN, NL, Canada
No full textCanada has become a prominent destination for international students from all over the world. This qualitative research aimed to explore the experience of grief and hope in international students in the Canadian academic context. Previous research on international students in the Canadian academic sector has addressed various challenges that international students face; however, little is known about grief and hope among international students in Canadian educational institutions. The study fills a gap in the literature on the Canadian academic context, examining how international master’s students navigate grief during their study period and move toward hope by exploring relationships, listening, and the unknown aspects of their lives. This qualitative research adheres to the narrative approach as a method of inquiry and implements thematic analysis. To gain in-depth knowledge, open-ended semi-structured interviews, observations, and documentation from social media have been collected from three former international master’s students of the Faculty of Education (2021-2023) at MUN, NL, Canada, who experienced grief while pursuing their degree. The results of this research discovered that grieving international students face isolation, academic discrepancy, homesickness, biases, financial problems, accommodation crises and cultural insensitivity, which impact them physically, mentally, and relationally. This research recommended that institutions and counsellors implement a more culturally sensitive approach to support grieving multicultural international students.Includes bibliographical references (pages 125-143
Preoperative CT-derived body composition as predictor of postoperative pancreatic fistula risk after whipple surgery
No full textPancreaticoduodenectomy (PD) is a primary treatment for pancreatic cancer but
carries a high risk of postoperative pancreatic fistula (POPF). Accurate prediction
of POPF is key for improving patient outcomes and guiding surgical decisions. This
study analyzed body composition (tissues within the lumbar range) and clinical factors
for predicting POPF, using a cohort of 777 patients. Volumes (V) and Hounsfield
Unit (HU) values were extracted from Computed Tomography (CT) scans using the
Data Analysis Facilitation Suite (DAFS) CT segmentation software, and logistic regression
was applied to analyze high- and low-risk groups (Fistula ±). For males,
Age at Surgery (p = 0.021), while for females, the Charlson Comorbidity Index (CCI)
(p = 0.018) and Malignancy (p = 0.037) were significantly associated with Fistula ±.
In males, Liver HU (p = 0.037), Gallbladder HU (p = 0.037), and Heart HU (p = 0.040),
while in females, Lung V (p = 0.044), Lung HU (p = 0.002), Trachea V (p = 0.029),
Trachea HU (p = 0.017), Heart V (p = 0.027), and Aorta V (p = 0.001), and for both
males and females respectively, Pancreas V (p = 0.006 and 0.047) exhibited significant
differences with Fistula ±. For tissue features, in males, SKM V (p = 0.029), while
in females, SKM HU (p = 0.006), FAT HU (p = 0.006), VAT HU (p = 0.000), SAT
V (p = 0.032), and SAT HU (p = 0.012), and in both genders, FAT V (p = 0.012
and 0.021), VAT V (p = 0.002 and 0.044), and the VAT/SKM V ratio (p = 0.006
and 0.032) were significantly associated with Fistula ±. For prediction, a sub-cohort
of 140 scans was used, with 11 key features selected. A weighted stratified five-fold
cross-validation approach was applied, with SHapley Additive exPlanations (SHAP)
ranking Age at Surgery, Pancreas HU, Liver HU, Aorta V, FAT HU, and SKM HU
as top predictors. The model achieved a mean Area Under the Curve (AUC) of 0.85
(training) and 0.80 (testing), with a mean Balanced Accuracy of 0.80 and 0.78, respectively.
These results highlight preoperative body composition as a non-invasive,
effective tool for predicting POPF risk and optimizing surgical planning, while underscoring
the importance of personalized, gender-specific risk assessments.Includes bibliographical references (pages 75-97
Design of solar energy system for a shop in Nigeria providing community cellphone charging service
No full textThe thesis presents the analysis of an existing solar power system at Better Mart and design of a new cell phone charging system that will be located at Remlek Bus stop Badore, Ajah Lagos State, Nigeria. The peak electrical load at the supermarket is 44.270 kW, this electrical load needs to be functional for the smooth running of businesses at Better Mart. Homer pro software was used to analyze and optimize the existing hybrid power system at the supermarket, the proposed system obtained from Homer pro includes; 240 Trina Duomax PEG14 PV panels with a rated capacity of 320 W each and a total of 76.8 kW which is connected to a 360 VDC bus, 50 kVA Caterpillar generator that runs on diesel, Grid system, Charge controller, 24 kW Fronious Symo Inverter and 30 pieces of each 12 V/220Ah EnerSys PowerSafe SBS 1800 battery storage. The result obtained from Homer pro proposed system includes 116,046 kWh/year of electrical power with a renewable fraction of 92%. The Net Present Cost (N.P.C.) of the proposed system is 0.03671 per kWh while the operating cost per year is $931.04. The new proposed system is recommended to reduce the electricity bills of Better Mart and to support an additional cellphone charging facility. The dynamic simulation of the hybrid power system was also carried in MATLAB environment, the result of the dynamic simulation shows that the dynamic model of the hybrid system is fast and efficient. A literature review of different types of mobile phone charger used in Nigeria was carried out and presented in this thesis. The design, dynamic modelling and simulation of a cellphone charging station was carried out in this thesis, the result and details of the simulation are presented in this thesis
New constructions of strong and Skolem starters
No full textThis thesis studies a class of combinatorial objects called strong starters, and their subclass,
strong Skolem starters, which are generated by Skolem sequences. In 1991, Shalaby
conjectured that the additive group ℤₙ, for any ≡ 1 or 3 (mod 8), ≥ 11, admits a
strong Skolem starter and constructed these starters of all admissible orders 11 ≤ ≤ 57.
Only finitely many strong Skolem starters have been known prior to the discovery of infinite
families of them in this thesis. A geometrical interpretation of strong Skolem starters and
explicit construction of the infinite cardioidal family of strong Skolem starters are offered
in the thesis. Then by employment of operations called products of starters, a new way of
generating strong Skolem starters of composite orders is received. This approach extends
the previous result by generating new infinite families of strong Skolem starters that are not
cardioidal. This discovery of the infinite families of strong Skolem starters gives significant
support to Shalaby’s conjecture.
Finally, a process of triplication of given strong starters (in ℤₚ, where 3 ∤ ) that yields
strong starters in ℤ₃ₚ and ℤ₉ₚ is thoroughly studied. The study results in the method that
allows us to construct such strong starters in ℤ₃ₚ for 7 ≤ ≤ 49, coprime to 6, and
in ℤ₉ₚ, = 5, 7, 11, 13, 17, by hand, which is otherwise quite a challenging task. This
research sheds a new light on Horton’s conjecture stating that strong starters exist in any
additive abelian group of odd orders except ℤ₃, ℤ₅, ℤ₃ + ℤ₃ and ℤ₉
Soil fertility characterization in podzolic soils of western Newfoundland using electromagnetic induction (EMI) sensors
No full textThis study was conducted to assess the possibility of predicting soil fertility properties in western Newfoundland using multi-coil (MC) and multi-frequency (MF) electromagnetic induction (EMI) sensors. Two studies on podzolic boreal soils evaluated the effectiveness of apparent electrical conductivity (ECa) and apparent magnetic susceptibility (MSa) from both MC and MF EMI sensors in characterizing available nitrogen (N), phosphorus (P) and soil organic matter (SOM) as significant soil fertility properties. The first study evaluated the effectiveness of MC and MF-EMI sensors to estimate soil ammonium (NH4+), nitrate (NO3-) and orthophosphate (PO43-) using ECa as a proxy under two different land uses. The second study assessed the effectiveness of MSa obtained from the MC and MF-EMI sensors to estimate and map SOM using a statistical and geostatistical analysis. The first study revealed the potential application of EMI ECa as a proxy to assess the spatial variability of NH4+, NO3- and PO43- within a narrow range of concentrations for a specific site. A comparison between statistical and geostatistical analysis in the second study suggested that cokriging of SOM with densely sampled EMI MSa could provide higher accuracy in estimating and mapping SOM in podzolic soil. Both studies revealed that multiple linear regression models were more effective with the inclusion of soil water than simple linear regression models in predicting soil nutrients and SOM. However, the MC EMI sensor provided a better estimation of soil nutrients, whereas the MF-EMI sensor predicted SOM more effectively. The overall findings from this study demonstrated the potential of EMI sensors as a more accurate and robust method than conventional methods to evaluate and map soil fertility properties in boreal podzolic soils. Further studies are required to assess the potential of EMI sensors under different crop types, management practices, and moisture regimes to estimate and map soil fertility properties for podzolic soils