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Open Access Publications from the University of California

Scholarly Works (44 results)

  • Article
Working Papers in Phonetics (2008)
    Cover page: WPP, No. 107: Shooting Through the Nose in Karekare: A Study of Nasally Released Stops in a Chadic Language
    • Article
    Works of Russell G. Schuh (2017)
      Cover page: A Chadic Cornucopia
      • Book
      Works of Russell G. Schuh (2017)
        • Article
        • Peer Reviewed
        Ufahamu: A Journal of African Studies, Volume 25, Issue 1 (1997)
        No abstract
          Cover page: The Use and Misuse of Language in the Study of African History
          • Article
          • Peer Reviewed
          UCLA Previously Published Works (2021)

          Background

          In response to the COVID-19 pandemic and associated adoption of scarce resource allocation (SRA) policies, we sought to rapidly deploy a novel survey to ascertain community values and preferences for SRA and to test the utility of a brief intervention to improve knowledge of and values alignment with a new SRA policy. Given social distancing and precipitous evolution of the pandemic, Internet-enabled recruitment was deemed the best method to engage a community-based sample. We quantify the efficiency and acceptability of this Internet-based recruitment for engaging a trial cohort and describe the approach used for implementing a health-related trial entirely online using off-the-shelf tools.

          Methods

          We recruited 1971 adult participants (≥ 18 years) via engagement with community partners and organizations and outreach through direct and social media messaging. We quantified response rate and participant characteristics of our sample, examine sample representativeness, and evaluate potential non-response bias.

          Results

          Recruitment was similarly derived from direct referral from partner organizations and broader social media based outreach, with extremely low study entry from organic (non-invited) search activity. Of social media platforms, Facebook was the highest yield recruitment source. Bot activity was present but minimal and identifiable through meta-data and engagement behavior. Recruited participants differed from broader populations in terms of sex, ethnicity, and education, but had similar prevalence of chronic conditions. Retention was satisfactory, with entrance into the first follow-up survey for 61% of those invited.

          Conclusions

          We demonstrate that rapid recruitment into a longitudinal intervention trial via social media is feasible, efficient, and acceptable. Recruitment in conjunction with community partners representing target populations, and with outreach across multiple platforms, is recommended to optimize sample size and diversity. Trial implementation, engagement tracking, and retention are feasible with off-the-shelf tools using preexisting platforms.

          Trial registration

          ClinicalTrials.gov NCT04373135 . Registered on May 4, 2020.
            Cover page: Rapid deployment of a community engagement study and educational trial via social media: implementation of the UC-COVID study
            • Thesis
            • Peer Reviewed
            UC San Diego Electronic Theses and Dissertations (2022)

            This dissertation presents some circuit complexity results and techniques. Circuit complexity is a branch of computational complexity dealing with classes of circuit families as opposed to classes of Turing Machines. Recent research has shown that there are rich connections between circuit complexity and other areas in theoretical computer science: Carmosino et al. construct learning algorithms from "natural" circuit lower bounds; Murray and Williams show that slightly better than brute-force SAT algorithms lead to circuit lower bounds against NP, and; Ilango, Ren, and Santhanam show that the existence of one-way functions is equivalent to hard distributions with certain properties existing for the Minimum Circuit Size Problem (MCSP). A common theme throughout these results is the concept of "meta-algorithms," algorithms which take functions as input and attempt to either construct objects computing the function in some way (e.g. construct a circuit that well-approximates the function), or finding some computationally relevant quantity (e.g. what is the minimum size of a circuit computing the function).

            This dissertation will focus on circuit complexity and MCSP for classes of low-depth circuits, particularly those of bounded fan-in. Here, we will present a lifting theorem from small-constant-depth bounded bottom fan-in circuits to larger-constant-depth bounded bottom fan-in circuits, leading to a reduction between MCSP for the corresponding classes. As part of this, we also present a new switching lemma, which may be of independent interest. We then demonstrate that MCSP for depth-2 bounded bottom fan-in circuits is NP-hard to compute, and is approximable within a factor of O(log N). After, we give a barrier result stating that "natural" reductions between MCSP for different fixed-depth circuit classes yields unexpectedly fast MCSP algorithms or new circuit lower bounds against these classes. Finally, we introduce a family of new models of communication complexity and give some upper and lower bounds in these models, with an eye to separating P from fan-in 2 O(log n)-depth circuits.

              Cover page: Connections Between and Techniques For Circuit Meta-Complexity Problems and Lower Bounds
              • Article
              • Peer Reviewed
              UC Irvine Previously Published Works (2015)
                • Article
                • Peer Reviewed
                UCLA Previously Published Works (2021)

                Background

                Detecting delirium with standardized assessment tools such as the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) is important, but such detection is frequently hampered by poor documentation and inappropriate "unable to assess" responses (in noncomatose patients).

                Objective

                To identify patient, clinical, and workplace factors that may impede or facilitate appropriate delirium assessment through use of the CAM-ICU, specifically documentation and inappropriate "unable to assess" responses.

                Methods

                An electronic health record-based data set was used to quantify CAM-ICU documentation and inappropriate "unable to assess" responses during 24 months. Associated patient (eg, age), clinical (eg, diagnosis), and workplace (eg, geographic location within the ICU, shift) factors were evaluated with multivariable regression.

                Results

                Of 28 586 CAM-ICU documentation opportunities, 66% were documented; 16% of documentations in alert or lightly sedated patients had inappropriate "unable to assess" responses. Night shift was associated with lower CAM-ICU documentation rates (P = .001), whereas physical restraints and location on side B (rather than side A) of the ICU were associated with higher documentation rates (P < .05 for both). Age older than 80 years, non-White race, intubation, and physical restraints were associated with more inappropriate "unable to assess" responses (all P < .05), as was infusion of propofol, midazolam, dexmedetomidine, or fentanyl (all P < .05).

                Conclusion

                Data from electronic health records can identify patient, clinical, and workplace factors associated with CAM-ICU documentation and inappropriate "unable to assess" responses, which can help target quality improvement efforts related to delirium assessment.
                  Cover page: Factors Influencing CAM-ICU Documentation and Inappropriate "Unable to Assess" Responses.
                  • Article
                  • Peer Reviewed
                  Working Papers in Phonetics (2010)

                  Bole is a Chadic language spoken in Yobe and Gombe States in northeastern Nigeria. The Bole tone system has two contrasting level tones, high (H) and low (L), which may be combined on heavy syllables to produce phonetic rising and falling tones. The prosody of intonation refers to lexical tones and the overall function of the utterance. Bole does not have lexical or phrasal stress, and intonation does not play a pragmatic role typical of stress languages, such as pitch raising to signal focus. The paper discusses intonation patterns of several phrasal types: declarative statements, yes/no questions of two types, WHquestions, vocatives, pleas, and lists. Certain interactions of intonation with tone apply to most of these phrase types: downdrift (esp. of H following L) across a phrase, phrase final tone lowering (extra lowering of phrase final L and plateauing of phrase final H after L), and boosting of H in the first HL sequence of a phrase. Special phrase final pitch phenomena in yes/no questions and pleas are described as appending extra-high (XH) and HL tones espectively. The last section discusses XH associated with ideophonic words, arguing that such words have lexical H tone which is intonationally altered to XH phrase finally.

                    Cover page: WPP, No. 108: Bole Intonation
                    • Article
                    • Peer Reviewed
                    UCLA Previously Published Works (2017)

                    Background

                    The mechanism by which various classes of medication reduce COPD exacerbation risk remains unknown. We hypothesized a correlation between reduced exacerbation risk and improvement in airway patency as measured according to FEV1.

                    Methods

                    By systematic review, COPD trials were identified that reported therapeutic changes in predose FEV1 (dFEV1) and occurrence of moderate to severe exacerbations. Using meta-regression analysis, a model was generated with dFEV1 as the moderator variable and the absolute difference in exacerbation rate (RD), ratio of exacerbation rates (RRs), or hazard ratio (HR) as dependent variables.

                    Results

                    The analysis of RD and RR included 119,227 patients, and the HR analysis included 73,475 patients. For every 100-mL change in predose FEV1, the HR decreased by 21% (95% CI, 17-26; P < .001; R2 = 0.85) and the absolute exacerbation rate decreased by 0.06 per patient per year (95% CI, 0.02-0.11; P = .009; R2 = 0.05), which corresponded to an RR of 0.86 (95% CI, 0.81-0.91; P < .001; R2 = 0.20). The relationship with exacerbation risk remained statistically significant across multiple subgroup analyses.

                    Conclusions

                    A significant correlation between increased FEV1 and lower COPD exacerbation risk suggests that airway patency is an important mechanism responsible for this effect.
                      Cover page: Reduced COPD Exacerbation Risk Correlates With Improved FEV1 A Meta-Regression Analysis
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