Defect tolerance: fundamental limits and examples

This paper addresses the problem of adding redundancy to a collection of physical objects so that the overall system is more robust to failures. In contrast to its information counterpart, which can exploit parity to protect multiple information symbols from a single erasure, physical redundancy can only be realized through duplication and substitution of objects. We propose a bipartite graph model for designing defect-tolerant systems, in which the defective objects are replaced by the judiciously connected redundant objects. The fundamental limits of this model are characterized under various asymptotic settings and both asymptotic and finite-size systems that approach these limits are constructed. Among other results, we show that the simple modular redundancy is in general suboptimal. As we develop, this combinatorial problem of defect tolerant system design has a natural interpretation as one of graph coloring, and the analysis is significantly different from that traditionally used in information redundancy for error-control codes.©201

Essays on Competition

This dissertation examines how competition shapes behaviors of governments and agents in different scenarios. Governments compete with each other to attract for mobile tax base. Agents and workers face competition to earn prizes and bonus. Competition is an effective way to incentivize proper behaviors. While in some cases, it causes inefficiency and social welfare loss. This dissertation studies environmental regulatory competition, tax competition, and tournament respectively. The first essay explores the question of whether OECD countries engage in strategic environmental policymaking and use environmental policies to compete for the investment. I directly estimate countries’ strategic interaction, which is the causal effect of other countries’ changes in environmental policies on one country’s environmental policy. Considering that the strategic interaction can be caused by distinct mechanisms, such as the coordination, competition for the investment, and pollution spillovers, this paper also disentangles different mechanisms. This paper employs a new index on measuring countries’ environmental policy stringency and uses spatial econometrics with the Generalized Methods of Moments continuously updated Instrumental Variables estimator. The panel dataset includes 26 OECD countries for the period 1990 to 2012. I find that there is a positive and statistically significant strategic interaction on environmental policy among countries. Moreover, the strategic responses in environmental policymaking are more evident among EU countries than others, and the strategic interaction is further reinforced after adopting the euro as a common currency. Interjurisdictional competition and transboundary pollution spillovers appear to play limited roles in causing the interaction. Essay 2 uses laboratory experiments to explore governments’ tax policies when there is tax competition. To the best of my knowledge, this is the first experiment paper on tax competition. I design a set of experiments to examine the effects of several factors on tax policies, such as the number of competing regions and the sensitivity of capital movement to the tax rate change. I find that the number of competing regions have a significant and direct impact on governments’ tax choices even keeping the sensitivity of capital movement constant. This finding has not been predicted in the theoretical literature. The sensitivity of capital movement also affect the tax rate choices, but the effect is not as large as the model prediction. I also find the communication among competing regions significantly improves the tax choices and bring about higher social welfare in general. The implications of the results are two folds. The first is that when analyzing tax competition issues, both from a policy perspective and theoretical study perspective, it is important to take the effect of the number of competing regions into consideration. The second policy implication is that it is helpful to promote better and more effective communication among governments. Essay 3 studies a multi-task tournament in which each agent undertakes two tasks. An agent’s effort on one task creates externalities on the performance of the other task of the agent as well as the performances of other competing agents. We discuss the design of an optimal tournament to achieve a social optimum in the presence of such externalities. In particular, we show that the traditional single-prized tournament is unable to elicit a social optimum, while a task-specific, multi-prized tournament, which we propose in this paper, can achieve socially optimal outcomes

Assessing Asian American and Pacific Islander (AAPI) Teachers’ Workplace Wellness

Teachers have many instructional, behavioral and classroom management, and administrative responsibilities (Cormier et al., 2021; Hilger et al., 2021; Roeser et al., 2022). There is limited research on occupational therapy\u27s role in teacher wellness. This study aimed to assess the challenges and barriers that Asian American and Pacific Islander (AAPI) teachers face, the causes of burnout, and the impact of the COVID-19 pandemic on AAPI teachers\u27 wellness. This study used a mixed methods research design, including an online survey and semi-structured interviews, focused on the challenges, barriers, strengths, and needs that AAPI teachers face in public, middle, and high schools in California. Themes from the data included (1) strengths and challenges as an AAPI teacher, (2) challenges and barriers from a systemic level, (3) the impact of COVID-19 on teachers, and (4) work overload. A strength of AAPI identity was having a cultural connection to AAPI students compared to their non-AAPI colleagues. However, AAPI teachers still face discrimination in the workplace. Teachers reported having a lack of support from administration, funding, and resources to reduce class sizes, increase teacher collaboration, disperse excessive tasks among other staff, and implement more helpful solutions. Results from the findings identify the potential role of occupational therapy in advocating for teacher support, workplace wellness, supporting work performance and satisfaction, implementing burnout-prevention strategies, and promoting teachers\u27 wellness and quality of life.https://soar.usa.edu/otdcapstonesfall2022/1005/thumbnail.jp

Use of the Physician Orders for Scope of Treatment Program in Indiana Nursing Homes

OBJECTIVES: To assess the use of the Indiana Physician Orders for Scope of Treatment (POST) form to record nursing home (NH) resident treatment preferences and associated practices. DESIGN: Survey. SETTING: Indiana NHs. PARTICIPANTS: Staff responsible for advance care planning in 535 NHs. MEASUREMENTS: Survey about use of the Indiana POST, related policies, and educational activities. METHODS: NHs were contacted by telephone or email. Nonresponders were sent a brief postcard survey. RESULTS: Ninety-one percent (n=486) of Indiana NHs participated, and 79% had experience with POST. Of the 65% of NHs that complete POST with residents, 46% reported that half or more residents had a POST form. POST was most often completed at the time of admission (68%). Only 52% of participants were aware of an existing facility policy regarding use of POST; 80% reported general staff education on POST. In the 172 NHs not using POST, reasons for not using it included unfamiliarity with the tool (23%) and lack of facility policies (21%). CONCLUSION: Almost 3 years after a grassroots campaign to introduce the voluntary Indiana POST program, a majority of NHs were using POST to support resident care. Areas for improvement include creating policies on POST for all NHs, training staff on POST conversations, and considering processes that may enhance the POST conversation, such as finding an optimal time to engage in conversations about treatment preferences other than a potentially rushed admission process

Rapidly Progressing Neurocognitive Disorder in a Male with FXTAS and Alzheimer's Disease.

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder that usually begins in the early 60s and affects carriers of premutation expansion (55-200 CGG repeats) of the fragile X mental retardation 1 (FMR1) gene. Additional disorders can co-occur with FXTAS including Alzheimer's disease (AD). Here we discuss a case report of a male with 67 CGG repeats in FMR1 who had mild late-onset FXTAS symptoms followed by neurocognitive disorder symptoms consistent with AD. The patient has developed tremor and ataxia that are the two characteristic symptoms of FXTAS. In addition, he shows rapid cognitive decline, brain atrophy most substantial in the medial temporal lobe, and decreased metabolism in the brain regions that are the characteristic findings of AD. The purpose of this study is to describe a patient profile with both diseases and review the details of an overlap between these two diseases

Unwieldy Object Delivery with Nonholonomic Mobile Base: A Stable Pushing Approach

This paper addresses the problem of pushing manipulation with nonholonomic mobile robots. Pushing is a fundamental skill that enables robots to move unwieldy objects that cannot be grasped. We propose a stable pushing method that maintains stiff contact between the robot and the object to avoid consuming repositioning actions. We prove that a line contact, rather than a single point contact, is necessary for nonholonomic robots to achieve stable pushing. We also show that the stable pushing constraint and the nonholonomic constraint of the robot can be simplified as a concise linear motion constraint. Then the pushing planning problem can be formulated as a constrained optimization problem using nonlinear model predictive control (NMPC). According to the experiments, our NMPC-based planner outperforms a reactive pushing strategy in terms of efficiency, reducing the robot's traveled distance by 23.8\% and time by 77.4\%. Furthermore, our method requires four fewer hyperparameters and decision variables than the Linear Time-Varying (LTV) MPC approach, making it easier to implement. Real-world experiments are carried out to validate the proposed method with two differential-drive robots, Husky and Boxer, under different friction conditions.Comment: The short version of the paper is accepted by RA

Factors Associated With Physical Activity Among Survivors Of Adolescent And Young Adult Cancer: The National Health Interview Survey

https://openworks.mdanderson.org/sumexp21/1006/thumbnail.jp

Evidence that Diclofenac and Celecoxib are thyroid hormone receptor beta antagonists

This document is the Accepted Manuscript version, made available under the terms of of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.Long term use of NSAIDs is linked to side effects such as gastric bleeding and myocardial infarction. AIMS: Use of in silico methods and pharmacology to investigate the potential for NSAIDs diclofenac, celecoxib and naproxen to bind to nuclear receptors. MATERIALS AND METHODS: In silico screening predicted that both diclofenac and celecoxib has the potential to bind to a number of different nuclear receptors; docking analysis confirmed a theoretical ability for diclofenac and celecoxib but not naproxen to bind to TRβ. KEY FINDINGS: Results from TRβ luciferase reporter assays confirmed that both diclofenac and celecoxib display TRβ antagonistic properties; celecoxib, IC50 3.6×10(-6)M, and diclofenac IC50 5.3×10(-6)M, comparable to the TRβ antagonist MLS (IC50 3.1×10(-6)M). In contrast naproxen, a cardio-sparing NSAID, lacked TRβ antagonist effects. In order to determine the effects of NSAIDs in whole organ in vitro, we used isometric wire myography to measure the changes to Triiodothyronine (T3) induced vasodilation of rat mesenteric arteries. Incubation of arteries in the presence of the TRβ antagonist MLS000389544 (10(-5)M), as well as diclofenac (10(-5)M) and celecoxib (10(-5)M) but not naproxen significantly inhibited T3 induced vasodilation compared to controls. SIGNIFICANCE: These results highlight the benefits of computational chemistry methods used to retrospectively analyse well known drugs for side effects. Using in silico and in vitro methods we have shown that both celecoxib and diclofenac but not naproxen exhibit off-target TRβ antagonist behaviour, which may be linked to their detrimental side effectsPeer reviewe