VictorJuiz/thesis huggingface dataset:
Undecidability in some field theories

This thesis is a study of undecidability in some field theories. Specifically, we are interested in geometrically oriented problems and have focused our attention in two directions along these lines. The first direction bases on determining the decidability of certain sets of first-order sentences over positive characteristic function fields. We will draw parallel to the problem of algorithmically determining in some cases the existence of points on varieties in positive characteristic function fields; equivalently the existence of certain maps between varieties over other positive characteristic fields.
The second direction bases on determining the decidability of first-order consequences of nonempty finite collections of L_r-sentences, true in fields with plenty of geometric structure. This is connected to the former direction by the fact that a decidable field has a recursive axiomatisation – what if we study a (nonempty) finite subset of the axiomatisation? Undecidability results.
Motivated by classification-theoretic conjectures, we will examine ‘wilder’ classes of fields in turn and generalise a result of Ziegler to NIP henselian nontrivially valued fields (and beyond). We move to PAC & PRC fields and prove they are finitely undecidable, resolving two open questions of Shlapentokh & Videla, and describe the difficulties that arise in adapting the proof to PpC fields. We pose the question: is every infinite field finitely undecidable?

Keywords: PAC fields
Hilbert's tenth problem
function fields
henselian valued fields
undecidability
PRC fields
hereditary undecidability
Advisor: Koenigsmann, J
Zilber, B
Undergraduate students' perception of academic freedom in Russia

This study aims to explore students’ academic freedom at Russian universities. Following the growing state control on universities, the restrictions on academic freedom at Russian universities have been gradually increasing. The existing literature on students’ academic freedom is extremely limited in contrast to a relatively well-established body of literature on academic freedom as it pertains to academics. To address this research gap, this dissertation attempts to answer two research questions: i) how do students define their academic freedom in Russian higher education?; ii) how much academic freedom can students in Russian higher education exercise? Through these research questions, the researcher investigates students’ understanding of academic freedom and the scope of academic freedom limitations at Russian universities. The study uses Biesta’s classification (2008) of the purposes of education (qualification, socialization, subjectification) to further elaborate on these research questions. Although Biesta’s framework does not directly engage with the questions about students’ academic freedom, it enables an analysis of how academic freedom limitations impacts students learning.
This study was designed as a qualitative case study. The data was collected through 20 online in-depth semi-structured interviews. The research setting covers four Russian universities in Saint Petersburg and Moscow. The study participants include third- and fourth-year undergraduate social science and humanities students completing their studies at the four selected Russian institutions. Interviews included questions about participants’ experiences at these universities and ways of exercising their academic freedom. Thematic analysis was used to analyse the qualitative data. The findings indicate that students predominantly define academic freedom as freedom of research and freedom of discussion. Students’ understanding of freedom includes the opportunities to choose any research topic, irrespective of how sensitive these topics might be. The ‘sensitivity’ is defined by the scope of critical analysis of Russia’s current political situation. Students’ perceptions of academic freedom are also linked with how much academic freedom students can exercise. Most students reported that they enjoyed a relatively great scope of academic freedom in universities. However, based on the students’ answers, this study identified explicit and implicit limitations on students’ academic freedom. Explicit limitations include administrative guidelines for changing research topics, avoiding discussing sensitive topics and strongly discouraging students’ engagement in politics. In contrast to explicit limitations, which were reported only in a few cases, most students indicated that they had experienced implicit limitations. These were not directly imposed on students but appeared in the subtle forms of recommendations and self-censorship practices from other members of the university community.

Keywords: Interviews
Russia's higher education
Students' academic freedom
CIE2022
Russia
CIE
Advisor: Chankseliani, M
A cultural perspective on the structure and function of social-emotional competencies: A study of the transition years into adolescence in Western China

Social-emotional competencies have been increasingly recognized as crucial for child development. Extensive evidence in Western countries suggests that social-emotional competencies have positive impacts on students' outcomes. The evidence has influenced the research and educational practices in Eastern countries such as China. However, few studies have examined the universals and particulars of social-emotional development in different cultures. Responding to the need, this study takes a cross-cultural perspective to examine the structure and function of social-emotional competencies during the transition to early adolescence in Western China.
More specially, the study tries to answer: (1) Does the structure of social-emotional competencies as defined by a widely used framework in Western countries replicate in a collectivistic culture? More specifically, is responsible decision-making, as defined in the framework, a valid factor in the construct of social-emotional competencies before adolescence? (2) Is the structure of social-emotional competencies stable during the transition to early adolescence? (3) Did participation in a SEL programme improve students’ academic performance on standardised tests in reading, math, and science? (4) Does teacher-student relationship mediate the association between social-emotional competencies and academic performance?
It was found that responsible decision marking did not stand as a separate domain as described in the Western framework. Instead, social harmony that represents the effort and willingness to achieve collective benefits emerged as a separate factor. The structure of social-emotional competencies was stable during the transition to early adolescence. Participation in the investigated SEL programme improved students’ academic performance on standardised tests in reading and math, but not in science. Teacher-student relationship mediated the association between social-emotional competencies and reading performance but not math performance. The findings were interpreted based on the existing literature. The implications to future research and educational practices were discussed.

Keywords: CDE2022
Western China
Secondary data analysis
Quantitative methodology
Measurement invariance analysis
Academic performance
Longitudinal mediation model
CDE
Cross-cultural perspective
Confirmatory factor analysis
Transition to adolescence
Social-emotional competencies
Exploratory factor analysis
Social-emotional learning
Advisor: Nag, S
Maternal language use during mother-child interactions and the development of ToM in Chinese children

Mothers’ preference for introducing and elaborating on mental states in conversations with their young children has been shown to be a significant predictor of children’s Theory of Mind development among Western samples. However, it is unclear whether this relationship still holds true in the Chinese cultural context. Exploratory in nature, the present study aims to study the relationship between mothers’ mental state talk and the development of Theory of Mind (ToM) in Chinese children (4-5 years old) following the framework of Peterson and Slaughter’s (2003) research. All participants (N = 94) were from middle-income families and were Chinese mothers of a 4-5-year-old typically developing children. Fifty-two pre-schoolers (M = 4.47 years, SD = .49) were boys.
Adopting a correlational study design, the current study first looks at if there were individual differences in mothers’ conversational styles with their children. By running correlational analyses examining the relationships between different conversational styles, this assumption was confirmed. Given individual differences did exist, Pearson’s correlation was performed to decide if mothers’ preferences of language use significantly correlated with ToM development in Chinese children. The result from the correlation analysis indicated that no significant correlation emerged between mothers' self-reported preferences for sophisticated explanations of mental states and parental report of children's ToM.
This null result was again confirmed by a hierarchical regression analysis showing that mothers’ conversational preferences were not predictors of Chinese children’s ToM development when relevant control variables were included in the analyses. Additionally, two correlational analyses were conducted to address the research question that whether children’s age and expressive vocabulary correlate with parental reports of ToM understandings. No correlation was found between age and ToM ability. However, there was a significant correlation between children’s expressive language and ToM, giving further support to the social constructivist account. An independent samples t-test to test the gender effect on parental-report ToM yielded no significant results.
Evidence of Internal consistency, content validity, and construct validity for the two translated questionnaires was given. However, accurate estimation of the psychometric properties of the two translated measures requires more research. Finally, Implications and future directions for research on the relationship between maternal mental state talk and ToM development in diverse and larger samples from a longitudinal lens were discussed.

Keywords: CDE2022
CDE
Maternal mental state talk
Online data collection
Correlational study
Language
Theory of Mind
Advisor: West, G
Development and understanding of catalytic functionalization of amides and other organic molecules

This thesis describes the development and mechanistic studies of an iridium-catalyzed reductive functionalization of amides and other catalytic transformations. The aim is to reveal and address the details of a wide variety of organic reactions, including some transition metal-catalyzed and organocatalytic transformations.
Chapter 1 introduces organic synthesis and computational chemistry and their historical backgrounds. In particular, reactions involving amines and organocatalysis are described. Chapter 2 details the development of the iridium-catalyzed reductive synthesis of azomethine ylides for [3+2] cycloaddition reactions. The unique selectivity of the cyclization reaction was extensively interrogated and explained by means of density functional theory. Chapter 3 describes mechanistic insight into the iridium-catalyzed reductive functionalization of amides. The detailed kinetic and computational studies revealed a full picture of the catalytic cycle and the high chemoselectivity in keeping with all experimental data. Chapter 4 describes computational mechanistic studies of enantioselective catalytic desymmetrization reactions of variously 4-substituted cyclohexanones. Three distinct catalytic reactions are studied, and the origin of the enantio- and diastereoselectivities for the transformations have been uncovered using density functional theory calculations. Chapter 5 describes computational mechanistic studies of enantioselective bifunctional iminophosphorane (BIMP)-catalyzed reactions. Three transformations using the BIMP catalyst are studied, and the chiral induction mechanisms originating from the stabilizing interactions are explained in detail.

Keywords: amide functionalization
iridium
density functional theory calculations
mechanistic study
Vaska's complex
Advisor: Dixon, DJ
A new texturing technique for silicon solar cells using gas phase etching

Solar energy is vital to combatting climate change. However, not all incident photons can transmit into a typical solar cell for electricity generation, a portion of the photons are lost to front surface reflectance. By changing the front surface texture of typical solar cells from microscale to nanoscale, the solar cell front surface reflectance (at wavelengths of interest), can be reduced to almost 0%. Such a change would increase the number of photons available in the solar cell for electricity generation. Despite the excellent optical properties nano-textures can offer, all current industrially relevant nanoscale texturing methods have drawbacks that prevent them from gaining a significant market share. This thesis explores texturing in the gas-phase to overcome the drawbacks of other nanoscale texturing techniques, whilst still providing exceptional optical properties to improve solar cell efficiency. Texturing Si in the gas-phase using ozone and hydrofluoric acid vapours at atmospheric pressure and low temperature was investigated. The premise of the texturing mechanism was to use the increased activity of ozone to oxidise the Si surface, at significantly lower temperatures than for O2 oxidation, then etch the oxide away using HF vapour, causing an ultra-low reflectance surface texture to form. A texturing tool was designed, built, and refined to study gas-phase texturing in this project. With this new tool, texturing reproducibility and uniformity were found to be dependent upon the surface chemistry of the Si wafers. By intentionally changing the surface chemistry via a precursor containing colloidal silica and IPA, reproducible and uniform texturing could be performed on sample sizes up to full-sized industrial Si wafers, with an average reflectance as low as 1.8% +/- 0.2%in 2 mins texturing. The mechanism behind the precursor was attributed to the Na+ counter-ions presentin the colloidal silica and a full texturing mechanism was proposed for the first time, accounting for the different morphologies gas-phase texturing could produce. Upon implementing gas-phase textured Si into a solar cell for the first time, a median cell efficiency of 17.24% was achieved, without any optimisation of the solar cell fabrication methods for the nano-texture.

Keywords: contamination
alkali metals
manufacturing
processing
silicon
gas phase
reflectance
sodium
chemistry
texturing
silicon solar cells
precursor
colloid
optical analysis
nanotexture
Advisor: Wilshaw, P
Bonilla Osorio, R
Deep learning techniques to bridge the gap between 2D and 3D ultrasound imaging

Three-dimensional (3D) ultrasound imaging has contributed to our understanding of fetal developmental processes in the womb by providing rich contextual information of the inherently 3D anatomies. However, its use is limited in clinical settings, due to the high purchasing costs and limited diagnostic practicality. Freehand two-dimensional (2D) ultrasound imaging, in contrast, is routinely used in standard obstetric exams. The low cost and portability of 2D ultrasound render it uniquely suitable for use in low- and middle-income settings. However, high level of expertise is always involved and it inherently lacks a 3D representation of the anatomies, which limit its potential for more accessible and advanced assessment. Capitalizing on the flexibility offered by freehand 2D ultrasound acquisition, this thesis presents a deep learning-based framework for optimizing the utilization and diagnostic power of 2D freehand ultrasound in fetal brain imaging.
First, a localization model is presented to predict the location of 2D ultrasound fetal brain scans in the 3D brain atlas. It is trained by sampling 2D slices from aligned 3D fetal brain volumes, such that heavy annotations for each 2D scan are not required. This can be used for scanning guidance and standard plane localization.
An unsupervised methodology is further proposed to adapt a trained localization model to freehand 2D ultrasound images acquired from arbitrary domains, for example sonographers, manufacturers and acquisition protocols. This enables the model to be used at the bedside in practice, where it can be fine-tuned with just the images acquired in any arbitrary domains before inference.
Building upon the ability to localize 2D scans in the 3D brain atlas, a framework is further presented to reconstruct 3D volumes from non-sensor-tracked 2D ultrasound images using implicit representation. With this slice-to-volume reconstruction framework, additional 3D information can be extracted from the 2D freehand scans.
Finally, a semi-automatic model, trained only on raw 3D volumes without any manual annotation, is presented to segment any arbitrary structures of interest in 3D medical volumes, while only requiring manual annotation of a single slice during inference. The model is tested on wide variety of medical imaging datasets and anatomical structures, verifying its generalizability.
In the design of the framework presented in this thesis, three fundamental principles, namely minimal human annotation, generalizability and sensorless operation, are followed to optimize its seamless integration into the clinical workflow. This may modernize freehand routine scanning and enhance its accessibility, while maximizing the clinical information gained from routine scans acquired as part of the continuum of pregnancy care.

Keywords: semi-automated segmentation
deep learning
freehand ultrasound acquisition
fetal neurosonography.
minimal human annotation
ultrasound imaging
covolutional neural network
unsupervised domain adaptation
implicit representation
self-supervised learning
Advisor: Namburete, A
Xie, W
Noble, J
Bilingualism and mathematical ability in typically developing primary school children: A systematic review

A large body of research has been dedicated to studying cognitive advantages of bilingualism in all ages. However, the research investigating the link between bilingualism and mathematical attainment in young learners is limited. This systematic review aims to investigate the relationship between bilingualism and mathematical attainment in typically developing primary school children (aged 5-11) and examine the roles of moderators (age and gender) and mediators (SES and ethnicity) of bilingualism on mathematical ability. The main purpose of the review was to synthesize evidence based on the empirical research. The author identified the studies examining the relationship between bilingualism and mathematical ability of school aged children from 7 electronic databases. Of the 559 total studies identified, 23 matched the eligibility criteria. The author categorized the studies into 3 groups based on the programs or the experimental conditions that they studied. Mixed Methods Assessment Tool (2018) was used to assess the risk of bias of individual studies and a cumulative confidence in the studies was synthesized. The results show that two-third of the studies on bilingualism and bilingual education were conducted in the US. The overall results demonstrate that bilingualism is positively associated with mathematical ability. Important findings and implications for the future research have been discussed.

Keywords: Systematic review
Mathematical ability
CDE2022
CDE
Bilingualism
Primary school children
Bilingual education
Advisor: West, G
Quantitative analysis of incorporation dynamics of conserved Centriole proteins in Drosophila early embryos

To divide efficiently, cells of animals and many other higher eukaryotes, rely upon centrosomes to help nucleate the bipolar mitotic spindle. At each division, two centrosomes are required, such that one centrosome is ultimately inherited by each daughter cell. Consequently, centrosomes must duplicate precisely once during each cycle of cell division. At the core of each centrosome is a mother centriole that can duplicate by growing a new daughter centriole off its side, which will later mature into a mother and nucleate its own centrosome. The core components of the centriole are highly conserved across higher eukaryotes, despite this there is still a lack of detail regarding their function and their hierarchy of assembly.
In this thesis, I perform a comparative analysis of the incorporation dynamics of several conserved centriole proteins, using both standard and super-resolution microscopy, and the Drosophila early embryo as a model. I show that the daughter centrioles in the Drosophila early embryo appear to begin assembling earlier than previously reported. Further, I provide evidence that several core centriole proteins may be recruited into a transient centrosomal primordial “soup” in addition to the centriole proper. In addition, I refine the order of assembly of the centriole - allowing incorporation of Sas-6, Ana2, Ana3, CEP135, Ana1 and Asl to be placed on a continuous timeline alongside the cell cycle. Finally, through the use of CEP135 mutants, I show that, CEP135 does not appear to be necessary to recruit Ana1 into centrioles, in contrast to previous findings.
In summary, my work redefines the initial incorporation dynamics of centriole assembly, challenging several previous assumptions and providing new avenues for interrogation of the specific functions of the core centriole proteins.

Keywords: Incoroporation
Centrioles
Centriolar
Centriole
Assembly
Dynamics
Drosophila
Centrosome
Advisor: Raff, J
Baena Lopez, L