VictorJuiz/thesis huggingface dataset:
The frequency and function of code-switching in a Korean-English bilingual child: a case study
Keywords: bilingualism
code-switching

The number of bilinguals who acquire their two languages at an early age is increasing in line with the global increase of international families due to immigration. This increase makes the investigation of bilingualism of much research interest. Code-switching (CS), a common bilingual practice of alternating between languages, is often studied as a means to gauge the language development of young bilinguals. As every bilingual experience is unique due to different amounts of exposure, language learning experiences, or socio-economic status, it is important to investigate different groups of bilingual children to understand their development of CS, and to find the factors that CS is associated with.
The purpose of the study is to explore the frequency, type, and functions of CS in a Korean-English bilingual two-year-old child in an immigrant context. The study investigates whether the frequency and direction of switching are correlated to a child’s developing mean length of utterance (MLU) and further explores the underlying reasons and functions that CS serves. Through the investigation, the study aims to contribute to the field of bilingual language development, especially in the context of Korean-English toddlers acquiring their languages in an immigrant context, which has not been extensively researched. The research adopts a case study method in which the participant, Suri, engages in play sessions with her parents. Findings revealed that the frequency and directionality of CS are likely to be aligned with language dominance: while the child receives less exposure to English in her environment, her MLU in English is higher, and CS was found primarily from Korean to English. Additional reasons for the asymmetric presence of CS were explored (e.g., in terms of socio-cultural context).
The study also explored the specific functions and reasons underlying the instances of CS. Compared to Korean-to-English CS, English-to-Korean CS displayed higher percentages of lexical and syntactic gap filling, which is a necessity-driven reason for CS. In both directions, preferences driven by contexts were the most predominant reasons for switching. In addition, instances of metalinguistic awareness were investigated with an aim to see whether Suri was code-switching as a result of confusion between the languages. Signs of language differentiation were demonstrated, indicating that CS was not a sign of confusion. Instead, CS served as a language practice to demonstrate preference, overcome linguistic deficiencies, and use familiar expressions, all aimed toward higher fluency to enrich communication.
The impact of picture books on Chinese low-level English learners’ reading comprehension and information acquisition: an experiment from the systemic functional perspective
Keywords: picture book
systemic functional linguistics
reading comprehension
vocabulary inference
multimodal discourse analysis
experiment

Picture book is a popular resource used among children in many educational situations. Teachers and parents use picture books to cultivate children’s literacy ability, aesthetic ability and help them to know about the world and themselves. Yet little is known about the relationships between picture book, reading comprehension, information acquisition, and vocabulary learning. This study examined whether picture book reading can help children understand story and infer the meaning of unfamiliar vocabulary. On the basis of the experiential meaning analysis using Systemic Functional Linguistics (SFL) and Multimodal Discourse Analysis (MDA) models, this study further examined whether children acquired three types of information: actions, participants and circumstance differently. The experiment was conducted in a Chinese public primary school with Grade 5 children, and 97 valid data was collected. Followed by the experiment, I also conducted guided think-aloud interviews to qualitatively examine the role of picture books in vocabulary meaning inference. The experimental results showed that the picture book (PB) group did not perform significantly better than the other two groups only receiving pictures or text, but participants in the PB group performed significantly better in answering the picture-version questions than the text-version questions, suggesting that picture information might be easier for children to acquire. For the information types, action information was the hardest type for all children to obtain, and the participant information was the most accessible one for the picture book group. Finally, the interview revealed that picture books could help children infer the meaning of unknown words. During the inference, children would use various types of information as references, including text, picture and context information provided by the book, prior world knowledge and prior linguistic knowledge. The interview also noted that low-level learners tend to use more picture references than text references.
Quantum control of molecular spins using electron spin resonance
Keywords: spin-electric coupling
quantum coherent nanoscience
entanglement
quantum
electron paramagnetic resonance
electron spin resonance
molecular magnets

Molecular magnets have been demonstrated to be promising candidates for quantum-coherent nanodevices, due to their long relaxation times and design flexibility. Building and scaling such devices presents several challenges. In this thesis, two problems related to scalability of molecular magnet architectures are investigated using electron spin resonance.
Using electric fields, rather than magnetic fields, to operate quantum devices, would radically improve addressability of individual spins. Electric field sensitivities of several molecular magnets, including frustrated Cu3
triangles, Cr7
Ni and Cr7
Mn rings and crystals of HoW10
complexes, are investigated through pulse sequences incorporating static electric fields. We find spin-electric couplings of various magnitudes, significant enough to manipulate the parameters of respective Hamiltonians to enable selective excitation and we demonstrate such excitation in the HoW10
molecule. We identify a path towards improving electric field sensitivities, through coupling structural distortions exhibiting high electric polarizability with the molecular spin Hamiltonian.
To operate assemblies of multiple molecular magnets as quantum devices, robust multiqubit gates, able to modify the amount of entanglement in the system, need to be implemented. Quantum state tomography may be employed to investigate the practical fidelity of such a gate and real entanglement it generates. Focusing on a weakly coupled dimer of two spin-
1
2
molecules, we propose an implementation of a two-qubit entangling gate followed by quantum state tomography using ensemble electron spin resonance. We investigate the limitations and requirements of the gate and the tomography procedure through theoretical arguments, simulations and experiments. We conclude that while challenging, reaching and demonstrating actual entanglement is within our capabilities using ensembles of molecular magnet dimers.
Twistor sigma models
Keywords: twistor theory
amplitudes
gravity

This thesis presents an overview of recent developments in the applications of twistor theory to the study of the gravitational S-matrix in flat as well as curved space-times. We begin by introducing the novel geometric tool of twistor sigma models. These are two-dimensional chiral sigma models governing holomorphic maps from the Riemann sphere into twistor spaces of self-dual vacuum space-times. What follows is a concise list of their main highlights, in the order that the reader will encounter them:
i) Solutions to the equations of motion of our sigma models provide the incidence relations of the twistor correspondence.
ii) On-shell actions of our models compute Kahler potentials for hyperkahler metrics on the associated space-times.
iii) Connected, tree-level correlators of our models give rise to tree-level, maximally helicity violating (MHV) graviton amplitudes of general relativity in flat space.
iv) The chiral algebra of operators in our models enjoys an action of the loop algebra of the wedge subalgebra of w(1+infinity). This is associated with the soft sector of celestial holography.
v) By coupling them to background twistor spaces of self-dual, vacuum space-times, our models can be used to derive tree-level MHV graviton amplitudes in self-dual, radiative space-times.
The self-dual space-times mentioned in the last point provide an ideal laboratory for studying amplitudes in curved backgrounds. The corresponding formulae for MHV graviton amplitudes are built out of Hodges' determinants familiar from flat space, but also exhibit exciting new structures like gravitational wave tails.
Textual criticism and linguistic diachrony in the book(s) of Kings
Keywords: Hebrew Bible
Book of Kings
textual criticism
ancient Hebrew
linguistics

This thesis approaches from the perspective of textual criticism the thorny issue of Ancient Hebrew and historical linguistics, above all the possibility of providing a relative date for the biblical texts. More specifically, I argue that the linguistic assessment of the variants contained in the analyzed texts provides a solid argument in favor of the traditional understanding and periodization of Ancient Hebrew. In order to illustrate my method and approach, I have selected some passages taken from the book(s) of Kings, which is remarkable for its textual development and history.
In the Introduction, I give an overview of the linguistic profile of Kings as well as of the main textual witnesses employed in this thesis. I also discuss my approach to the text and why it is relevant in the current discussion on Ancient Hebrew and linguistic diachrony. Chapter 1 focusses on the textual profile of the parallel accounts found in Isaiah 36-39 and 2 Kings 18-20. Almost all the variants are listed and, if necessary, discussed from a linguistic perspective, showing that later scribes could reproduce the pre-exilic language without difficulty. Chapter 2 deals with those variants from the parallel accounts that are linguistically relevant for a relative dating of the two texts. This proves that a series of late readings does indeed betray the hand of late scribes who let into the text linguistic elements that cannot have belonged to the pre-exilic idiom. Finally, in Chapter 3 I discuss more late and non-classical linguistic features that can be detected through the text-critical assessment of other portions of Kings. A concluding summary describes the results achieved by this two-pronged approach to the diachronic analysis of the biblical texts and announces what should be done next in this area.
Most of the linguistic and text-critical features are collected in an appendix found at the end.
The complexity of meta-computational problems
Keywords: circuit complexity
lower bounds in computational complexity
meta-complexity
computational learning theory

This thesis focuses on problems which themselves encode questions about circuits or algorithms, also called meta-computational problems. The thesis is centered on meta-computational problems like C-MCSP (minimum circuit size problem), C-Learnability and C-Satisfiability, for some circuit class C. We study mathematical questions pertaining to such problems, and their deep connections to the theory of lower bounds, which is a general theme that has attracted a lot of interest in recent years among complexity theorists.
We first study non-uniform lower bounds for MCSP (and its variants) motivated by its importance for the theory of Hardness Magnification. Thisphenomenon reduces major complexity separations (such as NP is not in NC^1) to proving “barely” non-trivial lower bounds for natural problems like MCSP against weak circuit classes. In most interesting cases, we already have such required lower bounds, but for a different, seemingly easier problem. Firstly, we establish that instantiations of magnification for certain variants of MCSP provably refute the existence of natural proofs against P/poly, which indicates that the natural proofs barrier by Razborov-Rudich may not be relevant to this approach. This is done by establishing a connection from hardness magnification to hardness of efficiently learning polynomial-sized circuits. Next, we investigate the future prospects of proving new lower bounds using magnification. We identify a new source of difficulty called the locality barrier, when trying to adapt existing lower bound techniques to prove strong separations via magnification. We show that this barrier applies to many current instantiations of hardness magnification, that involve a wide range of restricted computational models.
Next we consider learnability, and initiate a top-down study of hardness of learning circuit classes, i.e. we consider hardness of learning circuit classes more powerful than P/poly. Our goal is to understand the power and limitations of current complexity theoretic techniques in showing unconditional results for learning. We show unconditional hardness results for efficiently learning classes like BPE/poly, EXP/poly and PSPACE/poly on one hand, and on the other, show that it is implausible that one can extend these ideas to prove the NP-Hardness of learning classes like non-deterministic polynomial-sized circuits, i.e. NP/poly.
Finally, we consider the algorithmic question of counting the number of satisfying assignments of an input AC^0[2]-circuit. We construct a deterministic #SAT-algorithm for AC^0[2] circuits of depth d and size 2^(O(n^(1/d))), which beats brute-force running time non-trivially. The algorithm is designed using the Razborov-Smolensky polynomial method, whose original motivation was to prove AC^0[2] lower bounds. We then show a lower bound for E^NP against AC^0[2]-circuits of size 2^(Ω(n^(1/d+1))), which was the best known lower bound against this class until very recently.
Self-prioritization in motor responses
Keywords: Self-relevance
Movement time
Self-prioritization
Multisensory processing
Self-Prioritization Effect
Personal distance
Empathy
Arm-movement responses
Self-referential processing
Manual motor responses

In psychology, self-representation is widely held to guide our cognition and action. Self-relevant stimuli typically enhance our attention, perception, memory, and decision-making. A shape-label matching paradigm provides a standard method for investigating the self-advantage. However, the evidence suggests that self-prioritization (self-bias) in the matching task may be distinct from higher-level self-referential processing. To better understand the operation of this subcomponent of self, this thesis took a broad approach and asked: what are contextual constraints on the emergence and extent of self-bias in manual motor responses? Self-bias was examined with unisensory and multisensory stimuli and manipulations of stimulus factors and task-design, for the first time in a multisensory detection motor paradigm, in the initiation and execution of arm-movements, and in the relationship between self-bias and subjective perceptions of empathy and perceived closeness to others.
This thesis demonstrates that: (1) stimulus and label modality and task-design can modulate self-bias; (2) self-associations did not produce similar motor speed gains in simple detection motor responses, suggesting that self-bias in motor responses to unisensory and multisensory stimuli depends on explicit self–other evaluations; (3) self-bias can influence non-ballistic visual-feedback-driven arm-movements, ballistic arm-movements without visual feedback, and arm-movements directed ‘toward’ and ‘away’ from the stimuli; in other words, self-bias modulates ballistic arm-movements using proprioceptive, kinaesthetic, and tactile information (and potentially visual imagery), but not relevant exogenous visual input; (4) self-bias can influence both the initiation and execution of arm-movements; highlighting a modulation at multiple stages; (5) empathy and perceived closeness can predict self-bias and friend-bias, suggesting that the biases in manual motor responses are influenced by consciously-accessible representations of the interrelations between others and the self.
The wider implications of these findings are discussed in relation to neurodevelopmental disorders and relevance for future translational research. Taken together, these findings present a novel overview of self-bias in manual motor responses.
Epitaxial oxide thin films
Keywords: honeycomb structure
oxides
thin films

Growing transition metal oxides in the form of an ultrathin film can create new stoichiometries and structures that do not exist naturally, which may open new perspectives on the studies of oxide properties. This thesis focuses on the structural characterization of Nb, Ti, and V oxide thin films on the Au(111) substrates using scanning tunneling microscopy (STM).
The work starts with ring patterns created by M-Au substitutions (M = Nb, Ti, V, Mn). According to the rings’ radii and centers, we can conduct a three-dimensional (3D) mapping of the substitutional sites. The ring's morphology is related to the curvature anisotropy of the Au isoenergy surface in k-space.
Nb oxide has been studied most intensively in this project. Four structures of oxide monolayers have been identified which are (i) NbOx cluster, (ii) NbOy triangle, (iii) pinwheel, and (iv) the (2 × 2) Nb2O3 honeycomb (HC) structure. The pinwheel and honeycomb structures can form free films on the surface or embedded monolayers on the second layer. Nb-induced rings act as a precursor structure for an embedded monolayer.
Fourfold coordinated Nb atoms in Nb2O3 HC appear much brighter in STM images. The actual oxidation state of a fourfold coordinated Nb atom is between +4 and +5 due to the electron transfer to Au. According to the contrast difference and coordination number, mapping the Nb oxidation states with atomic resolution at room temperature can be realized. Besides, fourfold coordinated Nb atoms are involved in point defects, edges, and domain boundaries. Discussions on HC edges and defects are organized in two chapters. Comparative analysis between Nb2O3 and Ti2O3 constitutes pivotal sections.
Triangles and pinwheels are common structures in 2D materials. Nb and Ti oxides can form independently-standing triangles, and Nb/Ti/V oxides can generate both free and embedded pinwheel monolayers. A triangle building block model is proposed to elucidate the pinwheel comprising various sizes of triangle elements. Besides, Nb/Ti oxide triangles/pinwheels can be incorporated into HC monolayers by forming unique boundaries.
Mechanisms of oocyte activation in the presence and absence of PLCζ
Keywords: oocyte activation
PLCζ
sperm
fertilisation

Mammalian oocyte activation is thought to be caused by a sperm borne PLC subtype, called phospholipase C zeta1 (PLCζ). PLCζ RNA and protein microinjection and knockout studies in a mouse model have confirmed its primary role in releasing calcium (Ca2+) in the oocyte at fertilisation. Studies revealed that a few delayed Ca2+ transients can still occur in the oocyte after fertilisation with PLCζ knockout sperm, resulting in a reduced embryo formation rate and increased polyspermy, but otherwise apparently normal development to term, indicating the presence of a secondary factor(s) which can stimulate Ca2+ release in the oocyte. In this study, an attempt was made to identify such a secondary factor(s). In silico analysis of transcriptomic data revealed that mature sperm cells carry transcripts of PLCβ, PLCγ, PLCδ, and PLCζ subtypes. In MII oocytes, PLCβ1, PLCβ3, PLCγ1, and PLCγ2 were reported to be expressed. The mRNA and protein expression analysis showed reorganised expressions in the PLCζ knockout sperm cells. This reorganised expression levels of IP3 generators led to investigate PLC subtypes as potential secondary factors of oocyte activation. Proteomic analysis of PLCζ knockout sperm cells suggested that some proteins showing differential expression that are overexpressed in PLCζ knockout sperm participate in acrosome reaction, fusion and binding of gametes. Pharmacological interventions and Ca2+ dynamics investigations suggest that interference with Gαq (Gq) mediated PLCβ activation has a significant impact on Ca2+ release as well as fertilisation indicators, for both PLCζ knockout and wild type sperm, in distinct ways. Blocking Gq mediated PLCβ activation also blocks secondary Ca2+ transients triggered by PLCζ deficient sperm. Collectively, these data suggest that gametes express a number of PLC isoforms with differential expression in PLCζ knockout sperm, and PLCβ isoforms can act as potential secondary factors during oocyte activation thorough the Gq pathway, in parallel to PLCζ.
Investigating the organizing principles of the mouse claustrum
Keywords: neuroscience
neuronal tract tracing
optogenetics
electrophysiology
in vivo imaging
claustrum

The claustrum is highly interconnected with many structures in the brain, but the organizing principles governing its vast connectivity have yet to be fully explored. In this thesis, I investigate the architecture of circuits between the claustrum and neocortex and within the claustrum itself. Immunohistochemistry, neuronal tract tracing, in vitro whole-cell patch-clamp electrophysiology, dual-color optogenetic circuit mapping, and in vivo calcium imaging of neural activity were used to assess whether claustrum neurons combine inputs from multiple cortical areas and what impact claustrum neurons have on the cortex. I determined that individual claustrum neurons frequently integrate inputs from more than one cortical site, most commonly between regions of the frontal cortex. Additionally, I found that neurons in the claustrum receive inputs from an array of sensory and associative cortical areas, albeit to a lesser extent. Neuronal tract tracing and electrophysiology further indicated that input integration from frontal cortical regions depends on the cell type and output target of claustrum neurons. Optogenetic mapping revealed that intraclaustral connectivity was far more frequent than previously reported, particularly among neurons that did not share the same output target. Finally, activity in claustrum axons recorded with in vivo calcium imaging showed responses to combinations of sensory stimuli that were then transmitted to downstream cortical targets. My findings shed light on the organizing principles of claustrum connectivity, demonstrating that individual claustrum neurons integrate afferent inputs and redistribute this information back to cortex after performing output target- and cell-type-dependent local computations.