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Open Access Publications from the University of California

Scholarly Works (243 results)

  • Article
  • Peer Reviewed
Issues in Applied Linguistics, Volume 1, Issue 1 (1990)
    Cover page: Looking Back, Looking Ahead: An Interview with Evelyn Hatch
    • Article
    • Peer Reviewed
    Issues in Applied Linguistics, Volume 2, Issue 2 (1991)

    This study explores the relationship between scientists' orientation to one another and to an experimental apparatus, analyzing as data a videotaped authentic interaction among co-workers in a chemistry laboratory. It demonstrates how the scientists display systematic orientation to the apparatus as their common spatial point of reference on the one hand and as the physical embodiment of the experiment on the other hand.

      Cover page: Scientists' Orientation to an Experimental Apparatus in Their Interaction in a Chemistry Lab
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      • Peer Reviewed
      Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 23 (2001)
        Cover page: Mass and Count in Language and Cognition: Some Evidence from Language Comprehension
        • Article
        • Peer Reviewed
        UC Irvine Previously Published Works (2023)
        Cognitive control refers to the ability to maintain goal-relevant information in the face of distraction, making it a core construct for understanding human thought and behavior. There is great theoretical and practical value in building theories that can be used to explain or to predict variations in cognitive control as a function of experimental manipulations or individual differences. A critical step toward building such theories is determining which latent constructs are shared between laboratory tasks that are designed to measure cognitive control. In the current work, we examine this question in a novel way by formally linking computational models of two canonical cognitive control tasks, the Eriksen flanker and task-switching task. Specifically, we examine whether model parameters that capture cognitive control processes in one task can be swapped across models to make predictions about individual differences in performance on another task. We apply our modeling and analysis to a large scale data set from an online cognitive training platform, which optimizes our ability to detect individual differences in the data. Our results suggest that the flanker and task-switching tasks probe common control processes. This finding supports the view that higher level cognitive control processes as opposed to solely strategies in speed and accuracy tradeoffs, or perceptual processing and motor response speed are shared across the two tasks. We discuss how our computational modeling substitution approach addresses limitations of prior efforts to relate performance across different cognitive control tasks, and how our findings inform current theories of cognitive control. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
          Cover page: Linking Computational Models of Two Core Tasks of Cognitive Control
          • Article
          • Peer Reviewed
          Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 46 (2024)
          We investigate the relation between conceptual and syntactic structure by focusing on the phenomenon of circumstantial metonymy e.g., “Table #6 wants another pizza”. We hypothesize that the construal of a metonymic interpretation is facilitated when the metonymized argument e.g., “Table #6” is retrieved before the metonymy-trigger e.g., “wants”, since this gives the processor more time to build the event structure that metonymy demands. This predicts greater cost of metonymy composition when the argument is in object position (after the trigger) relative to subject position (before the trigger). An acceptability task shows a main effect of metonymy for both syntactic positions. A self-paced reading task demonstrates a cost for metonymy only in object position. This indicates that the cost of metonymy composition is rooted in the requirement that the conceptual structure for the metonymic argument be fully retrieved, a process constrained by the order of lexical retrieval provided by syntactic structure.
            Cover page: Linear Word Order Modulates the Cost of Metonymy Comprehension: Dynamics of Conceptual CompositionCreative Commons 'BY' version 4.0 license
            • Article
            • Peer Reviewed
            UC Irvine Previously Published Works (2006)
            Alzheimer's disease (AD) is the most common type of dementia in the US and much of the world with rates increasing exponentially from age 65. Increases in life expectancy in the last century have resulted in a large number of people living to old ages and will result in a quadrupling of AD cases by the middle of the century. Preventing or delaying the onset of AD could have a huge impact in the number of cases expected to develop. The oldest-old are the fastest growing segment of the population and are estimated to account for 12% of the population over 65. Establishing accurate estimates of dementia and AD rates in this group is crucial for public health planning. Prevalence and incidence estimates above age 85 are imprecise and inconsistent because of the lack of very old individuals in most studies. Moreover, risk and protective factors in our oldest citizens have been studied little, and clinical-pathological correlations appear to be poor. We introduce The 90+ Study, established to address some of the unanswered questions about AD and dementia in the oldest-old. Our preliminary results show that close to half of demented oldest-old do not have known cerebral pathology to account for their cognitive deficits. Furthermore, the APOE-e4 allele appears to be a risk factor for AD only in the women in our study. In addition to the challenge of preventing and treating AD, the oldest-old will require major investigative energy to better understand the concomitants of longevity, the causes of dementia, and the factors that promote successful aging in oldest citizens.
              Cover page: Alzheimer's and dementia in the oldest-old: a century of challenges.Creative Commons 'BY' version 4.0 license
              • Article
              • Peer Reviewed
              UC Irvine Previously Published Works (2020)
              Over the past century, we have witnessed a remarkable extension of human life expectancy by >27 years. Reflecting this accomplishment, people >= 90 years of age are now the fastest-growing segment of the population in most of the world. Indeed, more than half of all children born today in developed countries are expected to live to 100 years of age or beyond,(1) and it is remarkable how little we know about these pioneers of aging. Biomedical research tends to focus on disease and poor outcomes, but the oldest-old individuals who have reached extreme age with preserved cognitive health present an unparalleled opportunity to investigate factors that may promote successful cognitive aging throughout the lifespan, even in the presence of neuropathologic changes associated with cognitive loss and dementia.
                Cover page: Successful cognitive aging: What the oldest-old can teach us about resistance and resilience.Creative Commons 'BY' version 4.0 license
                • Article
                • Peer Reviewed
                UC Davis Previously Published Works (2022)
                Helicobacter pylori have coevolved with mankind since its origins, adapting to different human groups. In America, H. pylori has evolved into several subpopulations. We analysed the genome of 154 Colombian strains along with 1,091 strains from worldwide populations to discern the ancestry and adaption to Colombian people. Population structure and ancestry was inferred with FineStructure and ChromoPainter. Phylogenetic relationship and the relative effect of recombination were analysing the core SNPs. Also, a Fst index was calculated to identify the gene variants with the strongest fixation in the Colombian subpopulations compared to their parent population hspSWEurope. FineStructure allowed the identification of two Colombian subpopulations, the previously described hspSWEuropeColombia and a novel subpopulation named hspColombia, that included three subgroups following their geographic origin. Colombian subpopulations represent an admixture of European, African and Indigenous ancestry; although some genomes showed a high proportion of self identity, suggesting an advanced adaption to these mestizo Colombian groups. We found that recombination is more important that punctual mutations in H. pylori genome diversity, 13.9 more important in hspSWEurope, 12.5 in hspSWEColombia and 10.5 in hspColombia, reflecting the divergence of these subpopulations. Fst analysis identified 82 SNPs fixed in 26 genes of the hspColombia subpopulation that encode for outer membrane and central metabolism proteins. Strongest fixation indexes were identified in genes encoding HofC, HopE, FrpB-4 and Sialidase A. These findings demonstrate that H. pylori has evolved in Colombia to give rise to subpopulations with a self identity ancestry, reflected in allele changes on genes encoding for outer membrane proteins.
                  Cover page: Recombination events drives the emergence of Colombian Helicobacter pylori subpopulations with self-identity ancestryCreative Commons 'BY' version 4.0 license
                  • Article
                  • Peer Reviewed
                  Faculty Publications (1990)

                  A study of the Antarctic ozone hole has been made with a three-dimensional chemical transport model (CTM) using a linearized photochemistry for ozone. The tracer model uses the winds and convection from the Goddard Institute for Space Studies general circulation model (8° × 10° × 23 layers). The general circulation model (GCM) develops an Antarctic circumpolar vortex in early winter with strong westerlies that reverse in austral spring; the circulation compares favorably with the observed climatologies. A 4-year control run of the CTM with annually repeating winds produces ozone distributions that compare reasonably with the observed climatology. We examine different linearizations of the ozone chemistry and show that the calculated column ozone is sensitive to the chemical time constants in the lower stratosphere. In separate numerical experiments a hypothetical Antarctic ozone “hole” is induced on September 1 and on October 1; the CTM is integrated for 1 year with a linearized model that assumes standard photochemistry, not including the heterogeneous reactions and unusual chemistry associated with formation of the ozone hole. The initial depletion, assumed to be 90% of the O3poleward of 70°S between 22 and 200 mbar, amounts to about 5% of the total O3 in the southern hemisphere. As the vortex breaks down and the ozone hole is dispersed, significant depletions to column ozone, of order 10 Dobson units (3%) occur as far north as 40°S during austral summer. One year later, only 30% of the original depletion remains, mostly below 100 mbar and poleward of 30°S. The October 1 initialization is continued for a second year, the ozone hole being reinduced 1 year later with the same parameterization. The cumulative effects from the year before are noticeable but add only 20% to the depletion. A budget analysis for the southern high-latitude stratosphere (10–350 mbar × 31°–90°S) indicates the ozone hole is replenished equally by photochemical regeneration and by reduced transport of ozone into the troposphere, with a lesser fraction being filled in by an increased flux from the tropical stratosphere.

                    Cover page: Global impact of the Antarctic ozone hole: Dynamical dilution with a three-dimensional chemical transport modelCreative Commons 'BY' version 4.0 license
                    • Article
                    • Peer Reviewed
                    UC Irvine Previously Published Works (2009)

                    Objectives

                    To evaluate whether high levels of C-reactive protein (CRP) in serum are associated with greater risk of all-cause dementia or mortality in the oldest-old.

                    Design

                    Prospective.

                    Setting

                    Research clinic and in-home visits.

                    Participants

                    Population-based sample of adults (N=227; aged 93.9+/-2.8) from The 90+ Study, a longitudinal cohort study of people aged 90 and older.

                    Measurements

                    CRP levels were divided into three groups according to the assay detection limit: undetectable (<0.5 mg/dL), detectable (0.5-0.7 mg/dL), and elevated (> or =0.8 mg/dL). Neurological examination was used to determine dementia diagnosis (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria). Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were computed using Cox regression, and results were stratified according to and apolipoprotein E4 (APOE4) genotype.

                    Results

                    Subjects with detectable CRP levels had significantly greater risk of mortality (HR=1.7, 95% CI=1.0-2.9), but not dementia (HR=1.2, 95% CI=0.6-2.1), 0.4 to 4.5 years later than subjects with undetectable CRP. The highest relative risk for dementia and mortality was in APOE4 carriers with detectable CRP (dementia HR=4.5, 95% CI=0.9-23.3; mortality HR=5.6, 95% CI=1.0-30.7).

                    Conclusion

                    High levels of CRP are associated with greater risk of mortality in people aged 90 and older, particularly in APOE4 carriers. There was a trend toward greater risk of dementia in APOE4 carriers with high CRP levels, although this relationship did not reach significance. High levels of CRP in the oldest-old represent a risk factor for negative outcomes.
                      Cover page: High Levels of Serum C‐Reactive Protein Are Associated with Greater Risk of All‐Cause Mortality, but Not Dementia, in the Oldest‐Old: Results from The 90+ StudyCreative Commons 'BY' version 4.0 license
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