VictorJuiz/thesis huggingface dataset:
Three Essays on Firm Organization and Trade

This thesis examines how firms organize production and its relationship to international trade.In Chapter 1 I examine the assignment of workers to layers and firms. I use an administrative dataset of French workers to study the organization of manufacturing firms. First, I test whether higher ability workers are employed in the higher layers of firms. Second, I test whether there is positive assortative matching between workers in the different layers of firms. Third, I test whether abler managers supervise more workers. Finally, I test whether abler workers allow their managers to increase their span of control. I emphasize four results. First, abler workers are employed in the higher layers of firms. Second, I find evidence of positive assortative matching between workers in the different layers of firms. Third, I find evidence that abler managers supervise less workers. Finally, I also find weak evidence that abler workers allow their managers to increase their span of control.In chapter 2 I investigate the effect market toughness has on the organization of firms. To understand this relationship I develop a monopolistically competitive model with endogenous markups and heterogeneous firms. As in Garicano (2000) and Caliendo and Rossi-Hansberg (2012), production requires physical labour and knowledge. In the model, market size affects markups which then affects how firms organize production and their productivity. I also analyze how the distribution of organizations varies across markets of different sizes. The model predicts that in larger markets firms will have more layers, consistent with the data.In chapter 3 I examine the impact of international trade on the sorting of heterogeneous agents into sectors and occupations, and within sectors the matching of agents into teams, as well as the impact of trade on the distribution of earnings. To understand this relationship I extend Garicano and Rossi-Hansberg (2004) to two goods and two countries. I emphasize three results. First in an open economy, factor price equalization does not hold. Second, in a given sector, the returns to managers and production workers change in the same direction. And third whether international trade increases or decreases income inequality depends on the knowledge of the country.

Advisor: Gilles, Duranton
Micro- and Nano-scale Optoelectronic Devices Using Vanadium Dioxide

Miniaturization has the potential to reduce the size, cost, and power requirements of active optical devices. However, implementing (sub)wavelength-scale electro-optic switches with high efficiency, low insertion loss, and high extinction ratios remains challenging due to their small active volumes. Here, we use the insulator-metal phase transition of vanadium dioxide (VO2), which exhibits a large and reversible change in the refractive index across the phase transition to demonstrate compact, broadband, and efficient switches and photodetectors with record-setting characteristics. We begin by analyzing the electrical and optical properties of VO2 thin films across the phase transition and discuss the fabrication processes that yield micron- and nano-scale VO2 devices. We then demonstrate a surface plasmon thermo-optic switch, which achieves an extinction ratio of 10 dB in a 5 um long device, a record for plasmonic devices. The switch operates over a 100 nm optical bandwidth, and exhibits a thermally limited switching time of 40 us. We investigate the current and voltage induced switching of VO2 in nano-gap junctions and show optical switching times as short as 20 ns. The two terminal VO2 junctions are incorporated in a silicon photonics platform to yield silicon-VO2 hybrid waveguide devices with a record extinction ratio of 12 dB in a 1 um long device. In photodetector mode, the devices exhibit a nonlinear responsivity greater than 12 A/W for optical powers less than 1 uW. This device is the smallest electrically controlled and integrated switch and photodetector capable of achieving extinction ratios > 10 dB/um. We finally investigate the ultra-fast thermal heating in gold nano-apertures and demonstrate that electron heating can change the gold lattice temperature by 300 K in tens of picoseconds. These nano-apertures can be hybridized with VO2 to demonstrate high extinction and ultrafast optical switches.

Keywords: phase transition material
Vanadium dioxide
Advisor: Joyce, K.S. Poon
Bee Foraging in Space and Time: Linking Individual Behaviour to Pollination

In plant communities, flowers are patchy in space and time over many scales. Flower-feeding animals make complex foraging decisions in this setting, but they may respond in characteristic ways to variation in floral distribution and the presence of different plant species. For plant species that rely on animals to disperse their pollen for sexual reproduction, pollination will reflect these animal foraging decisions. Because many pollinators are highly mobile and return to foraging areas over time, they may affect plant pollination over scales broader than typically considered (a few metres and within foraging bouts). My dissertation explores how individual pollinators respond to floral resource variation, and the implications for plant pollination success. I do so over relatively broad spatial and temporal scales, by studying the interactions between bumble bees (Bombus spp.) and three plant species (Delphinium barbeyi, Gentianopsis detonsa, and Gentiana parryi) in Rocky Mountain subalpine meadows. As an assemblage, bumble bees concentrated their visits in resource rich areas over tens to hundreds of metres. This caused one plant species to act as a bumble bee magnet in an area, which increased the pollination of another plant up to 30 m away. In addition, many individual bees returned repeatedly to small areas, which also caused positive pollination interactions between plants. When a preferred flower declined, bees stayed faithful to their site and not their preferred species. Consequently, a newly-blooming plant quickly inherited a set of returning bees. I also showed that as a result of its late-flowering time, Gentiana receives visits by both female and male bumble bees. Intriguingly, the males were abundant and effective pollinators, despite not being considered by researchers as such. Overall, my work shows that pollinators can respond to flowers over broad spatial and temporal scales that can affect plant pollination success in unrecognized ways.

Keywords: Bombus
bumble bee
flower
foraging behaviour
pollination
spatial scale
Advisor: James, D Thomson
Nonlinear Periodic Structures: From Classical to Quantum Devices

In this thesis, nonlinear periodic structures and their applications in both classical and quantum regime are investigated. New theoretical models are developed, and novel applications of nonlinear periodic structures are proposed and demonstrated. The theoretical studies, both design and simulation, are based on but not limited to InGaAsP material. A new method, namely the time-domain transfer-matrix (TDTM), is presented to simulate optical pulse propagation in layered media with resonant nonlinearity. As there were no satisfactory methods in the literature to model this problem, in order to validate and compare with the TDTM method, the standard FDTD method is generalized to include the rate equation in the analysis of semi-conductors. Also in this work, optical manipulation of absorption in periodic structures is studied for the first time. Thanks to the large accessible nonlinearity that results from the absorption saturation and frequency selectivity of periodic structures, a sensitive and compact optical limiter is designed. The novel design and modeling work developed in this thesis has provided new insights and tools to the utilization of resonant nonlinearities in compact all-optical devices.The experimental studies are based on quasi-phase matched AlGaAs superlattice waveguides. These devices have been previously designed and used for classical optical wavelength conversion such as second harmonic generation and difference frequency generation. In this work, these devices are exploited for spontaneous down conversion, which is a quantum effect, for the first time, through this process, entangled photon pairs are generated. Unprecedented performance, in terms of brightness and purity, of III-V semiconductor-based entangled photon sources has been demonstrated here. Moreover, the quantum properties of these entangled photons are characterized. The experimental studies presented in this thesis open up new application areas for III-V nonlinear optical devices as quantum sources and convincingly demonstrate the promising role of such devices will play in future quantum technologies.

Keywords: entanglement
frequency conversion
Nonlinear optic
optical signal processing
Quantum
Advisor: Li, Qian
The Ecological Context of Pollination: Variation in an Apparent Mutualism

What makes a good pollinator? As pollinators perform the function of pollination, exporting and delivering grains between conspecific plant species, the floral visitor's foraging interests and the messy process of pollination interfere; many pollen grains are removed but not delivered. "Conditionally parasitic" floral visitors "waste" so much pollen (from a plant perspective) that they sometimes reduce total pollen delivery, the total number of pollen grains transferred to conspecific plant stigmas. Most pollinators visit plants with a diverse assemblage of other floral visitors; as pollinators remove, transport, and deposit pollen, they interact indirectly with one another through the supply of available pollen. These interactions can result in conditional parasitism because they affect the number of pollen grains that are successfully transported to stigmas. In this thesis, I explore how pollinator wastefulness and variation in pollinator assemblages may affect pollen export and delivery. I document a particular ecological situation in which a pollen-specialist ("oligolectic") bee and a nectar-collecting fly visit concurrently. In this system, pollen removal by the oligolectic bee results in substantial and rapid pollen depletion, which suggests that pollen wastefulness may be costly. The assemblage of pollinators varies widely throughout the geographic range of the plant; citizen scientists and I documented a consistent geographic pattern. These geographic differences correspond with variation in floral traits that are linked to pollen transfer by bees and flies. Finally, I use a simulation model to explore what ecological contexts will cause a floral visitor to increase or decrease overall pollen delivery. As a whole, these data provide substantial evidence that conditional parasitism may occur, and help elucidate aspects of plants, pollinators, and mechanisms of pollen transfer that may make it more likely. Moreover, I document plant traits that may be a result of selection mediated by conditionally parasitic floral visitors.

Keywords: Native bees
Plant-insect interactions
Pollination
Advisor: James, D Thomson
Affinity-based Growth Factor Delivery from Injectable Hydrogels for Tissue Engineering

Due to the complexities of tissue repair or regeneration processes, effective clinical strategies have been impaired by both poor delivery of therapeutic agents to the site of injury and a lack of sustained release that is required for long-term efficacy. In this thesis, a strategy for delivering protein therapeutics in a localized and sustained fashion is presented within the context of these regenerative medicine challenges. An affinity-based system was developed whereby transient interactions between complementary binding partners were used to slow the diffusional release of a therapeutic from a polymeric delivery matrix. The Src homology 3 (SH3) domain, which binds a library of SH3-binding peptides, with varying affinity (10

Keywords: affinity release
bioconjugation
controlled release
drug delivery
mathematical modelling
protein release
Advisor: Molly, S. Shoichet
Two Random Multiplicative Processes: Multiplicative Cascades and Eigenvectors of the Random Schrodinger Operator

In this thesis we focus on two distinct random processes constructed using a sequence of independent identically distributed random variables along with a product structure on the underlying space. The first, a collection of random variables attached to vertices of the rooted binary tree, uses the multiplicative structure of paths along the tree while the second, a collection of two by two random matrices, uses the usual multiplication of matrices.In the first chapter we construct a continuous time version of the multiplicative cascade. The multiplicative cascade can be thought of as a randomization of an initial measure on the boundary of a tree, constructed from an independent, identically distributed collection of random variables attached to the tree vertices. The new random measure is constructed from the old by weighting the measure of any vertex in the the tree by the product of the random variables along the path from the root to the vertex. Given an initial measure with certain regularity properties, we construct a continuous time, measure-valued process whose value at each time is a cascade of the initial one. We do this by replacing the random variables on the vertices with independent increment processes satisfying certain moment assumptions. This process has a Markov property: at any given time it is a cascade of the process at any earlier time by random variables that are independent of the past. It is also a martingale and, under certain extra conditions, it is also continuous. For Gaussian independent increments processes we develop the infinite-dimensional stochastic calculus that describes the evolution of the measure process, and use it to compute the optimal Holder exponent in the Wasserstein distance on measures.In the second chapter, we focus on the eigenvectors of the one-dimensional discrete random Schrodinger operator. This is the Hamiltonian operator on the lattice of integers given by the discrete Laplacian plus an independent, identically distributed delta potential at each point. We restrict this operator to a finite box, pick an eigenvector uniformly at random and characterize the scaling limit as we take the size of the box to infinity. We show that the envelope of this random eigenvector converges weakly to an exponential Brownian martingale. Our analysis uses the well known transfer matrix formulation of the spectral problem; the spectral information is encapsulated in a process of products of independent, identically distributed two by two random matrices. The limiting diffusion for this product process was developed in (Kritchevski, Valko, Virag - 2011) to study the local eigenvalue point process. Our work makes heavy use of that framework.

Keywords: Point Processes
Probability
Random Measures
Random Schrodinger Operators
Stochastic Process
Advisor: Balint, Virag
The Removal Property for Linear Configurations in Compact Abelian Groups

The combinatorial removal lemma states that, if a (hyper)graph K has not many copies of the fixed (hyper)graph H , then K can be made free of copies of H by removing a small set of (hyper)edges from K. In this thesis we show results for homomorphisms in finite abelian groups, and for integer linear systems over compact abelian groups that are analogous to the combinatorial removal lemma. The results state that, given some subsets Xi of the group, if there are not many solutions to the system Ax = 0, where the variables xi take values inXi, then there exist small subsets Xi' inside Xi such that there is no solution to the system Ax = 0 with xi in Xi \ Xi'. These results are shown by constructing an appropriate (hyper)graph that allows us to retrieve information on the elements to be removed from Xi using the set of (hyper)edges. These arithmetic removal lemmas extend the first removal lemma for groups proved by Green in 2005. They also present a comprehensive approach to results involving finding non-trivial linear configurations in dense sets. Examples of these types of results are SzemerĂŠdi's Theorem, which ensures the existence of arbitrarily long arithmetic progressions in sets of the integers with positive upper density, or its multidimensional version. The latter was first shown by Furstenberg and Katznelson in 1978 using ergodic theory and proves the existence of k-simplices in subsets containing a positive proportion of the integer lattice or rank k.

Keywords: compact abelian groups
homomorphisms of finite abelian groups
integer linear systems
regularity lemma
removal lemma
Advisor: zs, Szegedy Balรก
Aboriginal Education for Non-Aboriginal Learners: Engaging Teacher Candidates in an Immersive Cultural Experience

It is the expectation of this thesis that Aboriginal Education ought to be considered education for all learners, that is initiated, developed, facilitated and evaluated by Aboriginal people. In order to demonstrate this, this dissertation describes a weekend-long land-based Immersive Cultural Experience facilitated by two Anishinaabe Elders, involving six non-Aboriginal Teacher Candidates from the Ontario Institute for Studies in Education's Bachelor of Education program. The research was proposed and carried out respecting Indigenous Knowledge and the standards set out in the Ontario Federation of Indigenous Friendship Centres' Utility, Self-Voicing, Access, Inter-Relationality Research Framework. Experience was the principal method through which an expanded approach to Aboriginal Education was validated, however the main form of data collection for the Immersive Cultural Experience was twelve participant interviews. The analytical approach was interpretive and inductive, asking questions that related to experience, focusing on the improvement of professional teaching practice and ultimately how the participants perceived their experiences. The data outlined in this dissertation reflects the comments and reflections of the Teacher Candidates, drawn from a pre-experience interview, sharing circle that closed the Immersive Cultural Experience, debrief session in Toronto, post-experience interview, as well as correspondence. The interviews were structured to gather a range of information from reflection on Canadian identity, personal responsibility, spirituality, new styles of teaching and learning, and the utility of cultural immersion and experiential education. This dissertation contributes to theory development for Allyship and provides a best practices framework for intercultural engagement and experiential learning, outlining: a) knowing one's history; b) seeking local Knowledge Holders; c) understanding Aboriginal ethics protocols; d) collaborative planning; e) preparing participants; f) community-driven facilitation; g) debriefing the experience; and h) maintaining relationships. In following this framework, the participants were challenged to reflect on what they believed to be true about Aboriginal people, knowledges and cultures, and create a new understanding based on respect, engagement and relationship. The changes observed in the Teacher Candidates proved that the experience of being on the land, and learning directly from Aboriginal Elders has a significant impact on teachers' thinking about how to approach Aboriginal Education.

Keywords: Aboriginal education
Canadian identity
cultural immersion
experiential
Indigenous Knowledge
land-based
Advisor: Jean-Paul, Restoule
Functional Projections and Non-local Relations in Tongan Nominal Phrases

Functional Projections and Non-Local Relations in Tongan Nominal PhrasesThis dissertation explores several phenomena within Tongan nominal expressions - interactions amongst determiners, demonstratives, and definiteness; the morphosyntax of pronouns and possessive constructions; and the interactions of nominal aspect with numerals, number, and classification. Several motifs emerge, particularly the distributed nature of classification and quantification within nominal expressions, and the underlying locality of superficially long-distance syntactic relations.Although Tongan has pre-nominal articles often called definite and indefinite, I show that these encode specificity and non-specificity. Definiteness is marked via an anaphoric demonstrative clitic, the Definite Accent (DA), in the right periphery. A diachronic connection between the DA and spatial demonstratives has previously been shown, yet they do not instantiate the same syntactic category. The DA is now a marker of anaphoric deixis, interpreted as definiteness. It is merged above D

Keywords: Nominal Projection
Noun Phrase
Syntax
Tongan Language
Advisor: Diane, Massam
Guallatire: Negotiating Aymara Indigeneity and Rights of Ownership in the Lauca Biosphere Reserve, Northern Chile

My dissertation explores a multilayered landscape of contestation at the Aymara borderlands of Guallatire. Based on ethnographic fieldwork with guallatire単os in this Andean locality, I focus on how both the history of border institutionalization and the creation of the Lauca Biosphere Reserve impacted ethnicity processes and indigenous ownership in the highlands. I examine the politics of indigeneity as a mobile social formation and transnational field of governance, subjectivities and knowledges, along with notions of heritage shaped by the materiality of property. While struggling for cultural recognition and economic redistribution, guallatire単os have been confronted with a neoliberal state apparatus and violent mechanisms of government, including contradictory legislation which consequently has fragmented traditional native territories and communities, privatized land and water rights, and ultimately invisibilized Indigenous Peoples. However, the free market model has also shaped contested terrains between public and private sectors in the Lauca, paradoxically weakening the role of the state and causing friction among the various stakeholders involved in the Biosphere Reserve. By studying a series of state-driven `participatory meetings' for indigenous and touristic development, I conclude that participatory governance in the Lauca territory has challenged democratic practices and created spaces for indigenous recognition and political representation. Different strategies of resistance are continually performed by the Aymara to negotiate their ethnic identities and cultural boundaries in Northern Chile.

Keywords: Aymara
borderlands
Chile
heritage
indigeneity
property
Advisor: Valentina, Napolitano
Energy Efficient Routing Protocol Design and Implementation for Self-powered Wireless Sensor Networks

Advancements in digital circuitry, wireless transceivers and microelectro- mechanical systems have paved the way for the development of integrated sensor systems operating inside the unlicensed spread spectrum. Inch scale sensors can work unattended for long periods of time while energy harvesting techniques can extend their lifetime. A main challenge in these networks is energy efficiency. This thesis presents the design, implementation and evaluation of two routing protocols for a variety of applications with the main focus on energy efficiency.After reviewing the theory of opportunistic routing and opportunistic spectrum access, a scalable solution that combines the advantages of these approaches is presented. The CNOR protocol explores the spectrum availability while it uses opportunistic routing to take advantage of the broadcast nature of wireless communications. CNOR is designed for WSNs with limited power resources.Next, ECUR protocol for Self-powered WSNs is introduced. ECUR uses a novel prioritization metric for the neighbour nodes. ECUR protocol balances the residual energy level in a node with the packet advancement. Also, it takes into consideration the limited memory and processing capacity of the nodes.Lastly, the system implementation of the protocols is presented. Both protocols are examined through a novel Self-Powered Wireless Sensor Network testbed that was developed.

Keywords: energy efficient
routing protocol
self-powered
wireless sensor networks
Advisor: Dimitrios, Hatzinakos