VictorJuiz/thesis huggingface dataset:
Sectoral Mobility and Egyptian Labor Reform

This paper examines the effects of a recent labor law, which seeks to promote job creation in the private sector of the Egyptian labor market. Labor Law 12 of 2003 provides increased flexibility in the hiring and firing procedures for private sector employers in Egypt. This paper analyzes the effects of this legislation on new entrants to the labor force, experienced workers, public sector workers, and the unemployed. Specifically, this paper examines the mobility of workers from the public to the private sector and the wages of workers in both sectors. The empirical evidence suggests that the added non-wage benefits of this law effectively led to a transfer of workers from the public sector to the private sector. Egypt’s interim military-led government is seeking to repeal many of Egypt’s recent economic reforms aimed at liberalizing the Egyptian economy, including Labor Law 12. Based on my analysis I recommend that Labor Law 12 should be maintained and the new government should continue to increase incentives for private sector employment.

Keywords:  Department of Economics
Stanford Department of Economics
Labor
Private Sector
Public Sector
Economic Reform
Thesis
Advisor: Pencavel John
A self assembly approach to localization and patterning of optically resolved single molecules [electronic resource]

Directed assembly of single molecules is a central theme in nanotechnology. This body of work was inspired by a specific challenge involving ordered deposition of single DNAs on surfaces for massively parallel single molecule DNA sequencing via fluorescence microscopy. A potential 10-fold gain in data density is possible if single molecules can be forced into a regular array rather than randomly deposited. The dimensions of such an array are difficult to achieve with conventional lithography techniques. On one end, molecules must be separated by sufficient distance so their optical signatures do not overlap. This distance is on the order of hundreds of nanometers. On the other end, the attachment points for the molecules must have molecular dimensions. Bridging these two length scales is a formidable task. The ability to place nanometer scale objects with nanometer precision can been achieved through atomic force microscopy, scanning tunneling microscopy, optical tweezers, and ebeam lithography. All of these techniques, however, are serial in nature and hence do not serve the intended gain in data density. Another approach toward directed patterning of single molecules is through self-assembly. In this work, self-assembly of block copolymers is explored as a means to addressing the molecular and optical resolution length scales simultaneously. First, the challenge of molecular patterning for single molecule fluorescence microscopy is explored theoretically and the limits of this approach are defined. Block copolymers are introduced as a possible solution to generating the correct surface patterns for improved data density, and experimental results are compared to theoretical predictions. Second, the surface chemistry of these arrays is characterized, and I will show they can be selectively functionalized in preparation for directed assembly of DNAs. Third, these arrays are integrated into single molecule fluorescence imaging experiments to determine their potential for improved data density. What emerges from this work is not only a viable platform for increased single molecule fluorescence data density, but also a deeper understanding of the requirements for directed self-assembly of single molecules.

Keywords: Chemistry
Advisor: Bao Zhenan primary advisor. Thesis advisor
Chidsey Christopher E. D. (Christopher Elisha Dunn)
Dai Hongjie
A semidefinite programming method for graph realization and low rank matrix completion problem [electronic resource]

Owing to their high accuracy and ease of formulation, there has been great interest in applying convex optimization techniques, particularly semidefinite programming (SDP) relaxation, to the graph realization and sensor network localization problems in recent years. A drawback of such techniques is that the resulting convex program is often expensive to solve. In order to speed up computation, various edge sparsification heuristics have been proposed, whose aim is to reduce the number of edges in the input graph. Although these heuristics do reduce the size of the convex program and hence make it faster to solve, they are often ad hoc in nature and do not preserve the realization (or localization) properties of the input. As such, one often has to face a tradeoff between solution accuracy and computational effort. In this thesis, we propose a novel edge sparsification heuristic that can provably preserve the realization (or localization) properties of the original input. At the heart of our heuristic is a graph decomposition procedure that allows us to identify certain sparse generically universally rigid subgraphs of the input graph. Our computational results show that the proposed approach can significantly reduce the computational and memory complexities of SDP-based algorithms for solving the graph realization and sensor network localization problems. Moreover, it compares favorably with existing speedup approaches in terms of both accuracy and solution time. The graph realization problem indeed aims to reconstruct a matrix from a sampling of its entries, which can be viewed as a special case of the well-studied matrix completion problem. The main objective of the matrix completion problem is to design an efficient algorithm that can reconstruct a matrix by inspecting only a small number of its entries. Although, generally speaking, this is an impossible task, Candes and co-authors have recently shown that under a so-called incoherence assumption, a rank r n x n matrix can be reconstructed using SDP after one inspects O(nr log6 n) of its entries. We first provide an equivalent SDP formulation based on chordal decomposition, which has smaller SDP cones. Then we propose an alternative approach that can reconstruct a larger class of matrices by inspecting a significantly smaller number of the entries. Specifically, we first introduce a class of matrices, which we call stable matrices, and show that it includes all those that satisfy the incoherence assumption. Then, we propose a randomized basis pursuit (RBP) algorithm and show that it can reconstruct a stable rank r n x n matrix after inspecting O(nr log n) of its entries. Our sampling bound is only a logarithmic factor away from the information-theoretic limit and is essentially optimal.

Keywords: Computational and Mathematical Engineering.
Advisor: Ye Yinyu primary advisor. Thesis advisor
Papanicolaou George advisor. Thesis advisor
Saunders Michael A. advisor. Thesis advisor
Service after serving [electronic resource] : the hiring, performance, and compensation of military veterans in the United States federal civilian bureaucracy

Since the end of World War II, military veterans have staffed between one-quarter to one-half of all positions in the United States federal civilian bureaucracy. The abundance of former military personnel in federal employment results mainly from preferential hiring policies that partially exempt veterans--and, in some instances, their relatives--from merit screening. Yet, despite their prominence, veterans working in the federal civilian bureaucracy have received little attention from scholars: veterans' influence on government performance remains unknown, as does the effect of government employment on military veterans. In this dissertation, I provide new information about those issues, while also considering the normative and policy implications of veterans' preference policies. I find that that military veterans rank among the top performing civil servants and they increase the performance of programs housed in the bureaus in which they work. Moreover, this performance effect holds among veterans known to have benefited from preferential hiring. Despite this strong performance, statistical analyses reported herein indicate that military veterans employed in the federal service earn significantly lower wages than nonveteran federal employees. As well, I find that veterans employed as civil servants do not produce distinctively better outcomes for other veterans who seek government services. In sum, while veterans significantly improve federal government performance, federal employment does not offer exceptional advantages to military veterans. These findings carry normative and policy implications, which I discuss in this dissertation.

Keywords: Political Science.
Advisor: Moe Terry M. primary advisor. Thesis advisor
Fiorina Morris P. advisor. Thesis advisor
Ober Josiah advisor. Thesis advisor
Sharing information in rural communities through voice interaction [electronic resource]

Online communities enable people to participate in globally shared knowledge pools, but they are out of reach for poor and isolated communities around the world. Mobile phones have the potential to overcome the PC's accessibility, affordability, and familiarity barriers. However, most mobile information services limit rural populations to being passive knowledge consumers, not active producers. This dissertation explores the design and usage of voice-based social software for rural communities. We designed an application that allows small-scale farmers in India to share agricultural advice by posting, listening to, and replying to others' voice messages using any phone. It has served over 35,000 calls for over 4,000 callers since 2009. This dissertation presents research guided by three questions for designing systems in this context: First, how do you design effective UIs for navigating audio content? Second, what community dynamics emerge? Third, how do you support sustained community engagement? Prior work has assumed that spoken input is most effective for technology novices with limited literacy. We tested this hypothesis in controlled and natural settings, instead finding that touchtone input was more effective and preferable. Next, we tested whether information was more influential when it came from high-status scientists compared to peer farmers. Contrary to stated preference, participants acted more upon the same information when it came from a peer. Based on these and other experiences from our fieldwork, we developed a generalized software platform for deploying voice-based social media combining call-in and and call-out features, and web-based moderation. Finally, we analyzed the impact of access costs, finding that paying for calls had a dramatic impact to usage overall, and peer-to-peer responding in particular. We present some preliminary experiments using financial incentives and motivational messaging to boost usage.

Advisor: Klemmer Scott primary advisor. Thesis advisor
Parikh Tapan S. advisor. Thesis advisor
Winograd Terry advisor. Thesis advisor
Shock-turbulence interaction and Richtmyer-Meshkov instability in spherical geometry [electronic resource]

The canonical problems of shock-turbulence interaction and Richtmyer-Meshkov instability (RMI) are central to understanding the hydrodynamic processes involved in Inertial Confinement Fusion (ICF). Over the last few decades, there has been considerable analytical, computational and experimental work on the planar versions of these problems. In spite of the problem of interest being spherical in nature, there have been few studies in any of the three areas for these problems. It is not clear a priori, that the conclusions drawn from planar versions of these problems carry over to the spherical domain. The research presented here represents a first attempt to understand the hydrodynamic processes involved in an Inertial Fusion Engine (IFE) from capsule implosion to interaction of the resulting shock waves with the chamber gases. To abstract the key hydrodynamic components from the complex physics involved in an IFE, three canonical problems are identified and simulated: Interaction of a blast wave with isotropic turbulence, interaction of a converging shock with isotropic turbulence and RMI in spherical geometry. The last problem is a hydrodynamic abstraction of the capsule implosion itself, while the first two problems attempt to model the late stage interaction of fusion induced shock waves with chamber gases. On the shock-turbulence front, the study primarily focuses on the effect of shock strength relative to background turbulence on vorticity dynamics, which forms the cornerstone of any turbulence simulation. The effect of turbulence on shock structure is also characterized. For the converging shock, the maximum compression achieved in presence of turbulence is compared with that for a pure shock. For spherical RMI, focus is on evolution of the mixing layer and growth in vorticity and turbulent kinetic energy for different incident shock Mach numbers. The effect of interface perturbation on maximum compression achieved, which is one of the most important metrics for feasible ICF, is also considered.

Keywords: Aeronautics and Astronautics
Advisor: Lele Sanjiva K. (Sanjiva Keshava)
Cantwell Brian advisor. Thesis advisor
Moin Parviz advisor. Thesis advisor
Single channel full-duplex wireless radios [electronic resource]

Wireless networking is fast becoming the primary method for people to connect to the Internet and with each other. The available wireless spectrum is increasingly loaded, with users demanding higher performance and reliability from their wireless connections. This dissertation proposes single channel full-duplex as a new paradigm for wireless system design that can mitigate some of the throughput and reliability problems of today's wireless systems. With full-duplex wireless radios, a node can receive and transmit data at the same time, without using multiple wireless channels. At the physical layer, this capability can double the available throughput at a node. Further, sending and receiving at the same time allows a wireless node to exchange control messages while receiving data, making real-time feedback schemes possible. Such feedback, assumed to be impossible till now, allows network researchers to rethink the way wireless networks are designed. This dissertation shows that with the extra feedback channel available through full-duplexing, reliability in existing wireless networks can be significantly improved. Motivated by the promise that full-duplex wireless holds, this dissertation explores the challenges in implementing such radios and how these radios could influence the design of wireless networking stacks. The primary challenge in implementing a full-duplex wireless system is removing the self-interference from a node's transmit antenna to its receive antenna. This dissertation discusses various analog and digital techniques to cancel this self-interference. It presents an adaptive full-duplex wireless system that combines analog and digital self-interference cancellation to remove up to 73dB of self-interference. Exploiting full-duplexing to the fullest extent requires a redesign of higher layers, especially the MAC and network layers. This dissertation presents a full-duplex MAC layer implementation to show how full-duplexing can be leveraged to improve wireless reliability and performance. This implementation reduces hidden terminal losses by up to 88% and significantly improves network fairness and throughput. The main contribution of this dissertation is to motivate full-duplex radios as a direction for research on future wireless systems. It shows that designing full-duplex systems, while challenging, is feasible. It also presents many ideas on how full-duplexing could be used to improve a variety of wireless systems, including multi-hop data networks, cellular systems, and wireless LANs.

Keywords: Electrical Engineering
Advisor: Levis Philip primary advisor. Thesis advisor
O'Neill Daniel
Katti Sachin advisor. Thesis advisor
McKeown Nick advisor. Thesis advisor
Single-molecule and super-resolution in living cells [electronic resource]

Since the first successful detection single molecules over two decades ago, single-molecule spectroscopy has developed into a burgeoning field with a wealth of experiments at room temperature and inside living cells. Probing asynchronous and heterogeneous populations in situ, one molecule at a time, is not only desirable, but critical for many biological questions. Further, super-resolution imaging based on sequential imaging of sparse subsets of single molecules, has seen explosive growth within the last five years. This dissertation describes both the application of live-cell single-molecule imaging as an answer to important biological questions, and development and validation of fluorescent probes for targeted super-resolution imaging.

Keywords: Chemistry
Advisor: Moerner W. E. (William Esco)
Fayer Michael D. advisor. Thesis advisor
Pecora Robert
Single-molecule measurements of transcript elongation and termination by RNA polymerase [electronic resource]

Transcription by RNAP is highly regulated in both prokaryotic and eukaryotic cells, and the ability of the cell to differentiate and respond to its environment is largely due to this regulation. During elongation, for example, RNAP is known to momentarily halt in response to certain cellular signals, and this pause state has been implicated in the regulation of gene expression in both prokaryotic and eukaryotic organisms. In addition, once RNAP reaches the end of a gene, it must reliably terminate and release the newly-transcribed RNA, providing another potential point of regulation within different cell types. Both of these steps are crucial to ensure proper gene expression. In this dissertation, I focus on transcription elongation by both prokaryotic and eukaryotic RNA polymerases, as well as their regulation through pausing and termination. To probe the role of RNA hairpins in transcriptional pausing, a novel single-molecule "RNA-pulling" assay was used to block the formation of secondary structure in the nascent transcript. Force along the RNA did not significantly affect transcription elongation rates, pause frequencies, or pause lifetimes, indicating that short "ubiquitous" pauses are not a consequence of RNA hairpins. Force-based single-molecule techniques were also used to study the mechanism and energetics of transcription termination in bacteria. The data suggest two separate mechanisms for termination: one that involves hypertranslocation of RNAP along the DNA, and one that involves shearing of the RNA:DNA hybrid within the enzyme. In addition, a quantitative energetic model is presented that successfully predicts the termination efficiency of both wild-type and mutant terminators. Finally, the implementation of a novel optical-trapping assay capable of directly observing transcription by eukaryotic RNA polymerase II (RNAPII) molecules is described. This approach was used to probe the RNAPII nucleotide-addition cycle, as well as the role of the trigger loop (a conserved subdomain) in elongation. The results are consistent with a Brownian ratchet model of elongation which incorporates a secondary NTP binding site, and the trigger loop was found to modulate translocation, NTP binding, and catalysis, as well as substrate selection and mismatch recognition by RNAPII.

Keywords: Biophysics.
Advisor: Block Steven M. primary advisor. Thesis advisor
Kornberg Roger D.
Pande Vijay advisor. Thesis advisor
The SIRT1 deacetylase in neural stem cell function and oligodendrocyte generation in adults [electronic resource]

While the adult mammalian brain has a relatively limited regenerative capacity, it does contain pools of neural stem and progenitor cells that can give rise to new neurons and glia. The mechanisms that govern the production of new neurons in the adult brain are beginning to be well understood, but much less is known about the production of other cell lineages, in particular oligodendrocytes, from adult neural stem cells. Given the importance of oligodendrocytes in myelination, how they are generated in the adult brain is a question of fundamental importance for both normal and pathological conditions. Here we show that loss of SIRT1, a deacetylase that is crucial for metabolism and neuroprotection, enhances the production of both neural stem cells and oligodendrocyte progenitor cells in the adult brain and in vitro. Conditional deletion of SIRT1 in adult neural stem cells reveals a cell-autonomous action of SIRT1 in the generation of glia in the niche surrounding the subventricular zone. We find evidence that SIRT1 loss may alter the pool of proliferating oligodendrocyte progenitor cells by controlling the PDGF receptor a (PDGFR a) signaling pathway. SIRT1 loss increases acetylation of lysine 9 of histone H3 at the Pdgfra gene locus, affecting Pdgfra expression and activation of downstream PI3K-Akt and p38 MAPK signaling pathways in adult neural stem and progenitor cells. The observation that a drug-targetable deacetylase and downstream signaling pathways impact oligodendrocyte expansion may facilitate the generation of oligodendrocytes for stem cell therapies to treat injury and demyelinating diseases.

Advisor: Brunet Anne
Andreasson Katrin advisor. Thesis advisor
Palmer Theo advisor. Thesis advisor
Rando Thomas A.
Skill and billiards [electronic resource]

Computational pool is a relatively recent entrant into the group of games played by computer agents. It features a novel combination of properties that distinguish it from other such games, including continuous action and state spaces, uncertainty in execution, a unique turn-taking structure, and of course an adversarial nature. This combination leads to new challenges, both in modeling and reasoning about the game and in designing agents for effective play. We address the modeling challenges by presenting a model of generalized billiards games and showing that an equilibrium exists within this model. To address the practical challenges of designing an agent, we discuss CueCard, our agent which won the 2008 computational pool tournament, with a special focus on which new advancements made this agent successful. The second portion of the dissertation focuses on a topic inspired by the computational pool domain, that of execution skill. In many AI settings an agent is comprised of both action-planning and action-execution components. We first present experimental work in which we examine the relationship between the precision of the execution component, the intelligence of the planning component, and the overall success of the agent within our computational pool framework. Our motivation lies in determining whether higher execution skill rewards more strategic playing. Finally, we present a method for modeling imperfect execution skill in normal form games and examine the effect that changing execution skill levels can have in these games. We then study games in which players have imperfect execution skill and one player's true skill is not common knowledge. In these settings the possibility arises of a player "hustling", or pretending to have lower execution skill than they actually have. Focusing on repeated zero-sum games, we provide a hustle-proof strategy; this strategy guarantees a player the same payoff without knowledge of the opponents execution skill level as they could guarantee with knowledge of the opponent's true execution skill level.

Advisor: Shoham Yoav primary advisor. Thesis advisor
Leskovec Jurij advisor. Thesis advisor
Wilson Robert advisor. Thesis advisor