University of Illinois at Chicago
University of Illinois at Chicago: UIC INDIGO (INtellectual property in DIGital form available online in an Open environment)Not a member yet
21439 research outputs found
Sort by
Litmus Testing CPython Without the Global Interpreter Lock
No full textCPython's Global Interpreter Lock (GIL) has been a long-standing performance bottleneck for the Python programming language, forcing Python threads to run one at a time and preventing real shared memory parallelism in Python programs. Recently, the Python Steering Council has accepted a proposal to eliminate the GIL and bring real multithreading to CPython for the first time. An experimental "free-threaded" version of CPython implementing this proposal is now being actively developed by the core CPython team. In this thesis, we explore the consequences of removing the GIL on CPython's memory model, the semantics it guarantees to multithreaded programs. We argue that CPython has historically provided an extremely strong memory model, sequential consistency, to Python programs, and that without careful implementation of free-threading, this may no longer be the case. We characterize the memory model of free-threaded CPython using litmus tests, small concurrent programs that expose violations of sequential consistency, and we aim to explain our results using measurements collected from analogous litmus tests in lower-level languages and hardware performance counters. We also use a simple form of mutation testing to validate that our litmus testing strategy can effectively detect sequential consistency violations in CPython's free-threaded implementation
Interplay between Aromaticity and Photophysics in Novel Pro-aromatic Thioamide Chromophores
No full textThe molecular aromaticity of π-conjugated annulenes can be perturbed using chemical functionalization to afford novel systems that exhibit attractive properties. Classical aromatic systems are expected to obey the Hückel rule in the ground state. However, upon photo-excitation of those Hückel-type molecules, a change/reversal in aromaticity characters in the excited state could compromise the stability of the transient species. To improve the photo kinetics and stability of transient species derived from Hückel-type molecules or chromophores, one can (i) perturb the intrinsic global aromaticity of the ground-state molecules or (ii) introduce pro-aromatic moieties in the backbone of these molecules. The latter strategy would afford molecular systems with moieties having varying degrees of aromaticity. Expectedly, upon photo excitation, aromaticity reversal would create excited transients having enhanced local aromaticity, ensuring greater photostability and extended excited state kinetics. Alternatively, one can devise molecular systems that feature both global Hückel and local Baird aromaticity such that the photo excited properties of these novel systems can be influenced by Baird aromaticity, which could facilitate efficient singlet-to-triplet intersystem crossing (ISC).This dissertation focuses on pro-aromatic quinoidal scene thioamides (QDM 1) and its derivatives that were prepared to elucidate the role of molecular aromaticity and π-conjugation on ground-state stability and excited-state behaviors. QDM 1 was used as a light-harvesting triplet chromophore in/for photon-energy management and non-linear photophysical processes. While the unique photophysics of QDM 1 was found to be influenced by aromaticity reversal, it was also found that the presence of the thioamide functionality induced non-adiabatic photophysics, ensuring efficient ISC. The synergy between molecular aromaticity and “sulfur-effect” was explored with derivatives 2–8: Derivatives 2–4 were prepared to interrogate the role of ground-state aromaticity imbalance (aromaticity extension) on the stability and triplet photophysics of QDM 1, derivatives 4–6 were investigated to unravel the effect of the chalcogen atoms on the triplet photo-behavior of QDM 1, and derivatives 7 and 8 were studied to understand the interplay between pro-aromaticity or π-regression and “sulfur-effect” on the excited-state photo behavior of QDM 1. The structural alterations of QDM 1 have shed light on the influence of ground- and excited-state aromaticity on photo-behavior(s) of novel pro-aromatic thioamide chromophores that were investigated throughout my graduate research journey. My dissertation will present a chronological insight into the design, synthesis, photophysics, and computational investigations of pro-aromatic quinoidal acenethioamide QDM 1 and its derivatives
The Promise of Student Pathway Programs in Diversifying and Replenishing the Public Health Workforce: The Connecticut Public Health Fellowship Program
No full textContext: The ongoing public health workforce shortage poses a significant threat to the United States population. The COVID-19 pandemic has highlighted this crisis, drawing attention to the lack of critical diversity within the public health workforce, which is necessary to address health equity. Despite the proliferation of public health programs attracting graduate students, there has not been a corresponding increase in the number or diversity of employees within local and state public health agencies, which are the backbone of the public health infrastructure. While internships are generally recognized as valuable experiences for individuals seeking to enter public health, there is limited research on the effectiveness of pathway programs (initiatives designed to help students transition from undergraduate or graduate school to the workforce) in recruiting diverse candidates and ultimately meeting and sustaining public health workforce demand. Therefore, it is essential to examine internship models not only as avenues for sustaining the public health workforce but also as mechanisms for attracting and serving historically marginalized populations.Case Study: Sponsored by the Connecticut Department of Public Health and supported by the Centers for Disease Control and Prevention’s (CDC) Crisis Response Cooperative Agreement COVID-19 Public Health Workforce Supplemental Funding, the Connecticut Public Health Fellowship Program (CT PHFP) “aims to build interest in public health careers by supporting college and graduate students in high-quality public health fellowship placements throughout Connecticut” (Yale School of Public Health, n.d.). The CT PHFP provides third- or fourth-year undergraduate or graduate-level students enrolled in any accredited academic institution and in any degree program relevant to public health with administrative support, coaching, program orientation, and a $3,500 stipend to support their internship experience. From July 2022 through June 2024, 97 fellows have been supported through the CT PHFP and placed with local and state public health agencies and community organizations across Connecticut. Acceptance into the CT PHFP was on a rolling basis, accommodating academic schedules, personal limitations such as work/family obligations or transportation access, and host agency capacities.Methods:Quantitative Component: Using the CT PHFP as an exemplary case, program data from CT PHFP applications were analyzed to assess demographic differences between fellows and non-fellows using chi-square tests and t-tests, where applicable. Fellows were also compared to a representative sample of PH students from the U.S., New England, and Connecticut.Qualitative Component: Interviews were conducted with 13 out of the 97 CT PHFP alumni to assess barriers and facilitators of access and participation, using a modified framework analysis approach. Additionally, two meetings were held with New England preceptors (n=27) as a form of member checking to review findings and generate recommendations for future programming.Evaluation: Analysis of the program data did not yield statistically significant differences between CT PHFP fellows and non-fellows. Facilitators to access and participation included clear application processes, stipends, alignment of tasks with career goals, program flexibility, mentoring, networking opportunities, inclusive cultures, and accessible sites. Barriers included financial constraints, limited awareness of opportunities, logistical challenges, training scheduling, limited leadership diversity, lack of project structure, and task misalignment.Discussion: The CT PHFP has the potential to serve as a promising model for addressing the adaptive challenge of public health workforce shortages and diversity gaps. Reducing barriers and enhancing facilitators can attract and retain diverse talent, strengthening public health infrastructure. Continued support and improvement are crucial for building a robust, well-prepared public health workforce capable of meeting future health challenges. Findings provide valuable insights into the effectiveness of internship models in promoting diversity within the public health workforce. These insights will be crucial not only for Connecticut but also for national and statewide programs aiming to address similar challenges. The results will be utilized in the creation of a pathway program toolkit through the New England Public Health Training Center (NEPHTC) network, providing a structured approach for other regions to implement similar initiatives. Future research should examine the long-term impacts of such public health experiential learning initiatives on a large scale, ultimately enhancing the capacity to address health equity and improve public health outcomes nationwide.</p
Kenya’s Digital First Responders: The Hidden Workforce Powering Global Tech
No full textThis report focuses on data workers in a growing technology hub: Nairobi, Kenya. Fueled by a young, educated, tech-savvy population, a workforce with cultural and linguistic proficiency, an economy with globally competitive labor costs, and significant government efforts to lure tech-related investment, Kenya has emerged as a center for digital labor. Thousands of Kenyans are employed by business process outsourcing companies (BPOs) or work for online labor platforms, undertaking data annotation and content moderation on behalf of major global corporations. A defining characteristic of the digital economy, in Kenya and elsewhere, is the complex web of outsourcing relationships. Major tech companies rarely employ labelers or moderators directly. Instead, they contract the work to large multinational BPOs or specialized platforms that, in turn, often subcontract parts of the work to smaller, local BPOs or use labor brokers to enlist workers from local labor markets. The layers of subcontracting in digital supply chains create opacity: workers at the end of the chain have no visibility into the end client whose products they are building or safeguarding. Outsourcing has profound impacts on working conditions, as layers of intermediaries skim margins and make it difficult for workers to hold lead firms accountable for labor violations or poor treatment. This report sheds light on the experiences of Kenyan data workers at the far reaches of digital supply chains and offers recommendations based on workers’ desires for improved working conditions.</p
Power Health: Anonymized focus group transcripts from women participating in a study related to menstrual health and sexual and reproductive health
No full textThese are transcribed and translated transcripts resulting from focus group discussions among women taking part in a study related to menstrual health challenges, needs, and preferences, and impact on work.</p
Design of the What’s On Your Kid’s Plate SNAP Study
No full textThis research brief describes the design and baseline data from the What’s On Your Kid’s Plate study, which will assess the impact of RI Eat Well Be Well program on parent-reported frequency of children’s fruit and vegetable consumption and measures related to the home food environment, eating behaviors, food parenting practices, and other factors influencing child dietary intake.</p
Revolutionizing Electronic Cooling: Ultra-short-pulsed Laser Processed Surfaces in Wick-Free Vapor Chambers
No full textIn the ever-evolving landscape of modern high-power electronics, efficient thermal management solutions play a pivotal role in determining device performance and longevity. Vapor chambers have long been heralded as effective tools for managing high heat-flux scenarios. Traditionally, vapor chambers are wick-lined; however, they have some inherent limitations. These chambers rely on wick structures to resupply liquid to the evaporator, where the fluid undergoes vaporization due to the heat generated by the electronic components. While the effectiveness of vapor chambers has been demonstrated, wick-lined vapor chambers face challenges, such as the capillary limit, pore blocking, and added weight. To address these limitations, researchers have turned to wick-free vapor chambers (WFVC). These systems eliminate the need for wick structures, relying instead on the surface properties of the evaporator and condenser surfaces to drive liquid flow. The success of wick-free vapor chambers hinges on the skin-deep surface microstructures present on these surfaces and wettability patterning. In this study, we explore wick-free vapor chambers equipped with uniformly superhydrophilic evaporators created through ultra-short pulsed laser surface processing (ULSP), utilizing two different laser processing methods to functionalize the evaporators. Our findings reveal that ULSP surfaces used in wick-free vapor chambers produce VC thermal resistances as low as 0.12 K/W. What sets the present approach apart is the absence of surface wettability patterning, unlike previous wettability-patterned vapor chambers that combined distributed philic and phobic domains to move condensate as needed in the device, in turn improving performance, as quantified by thermal resistance.</p
Data sources:
Access Repository Dashboard
Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇