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Open Access Publications from the University of California

Scholarly Works (6 results)

  • Article
Policy Briefs (2020)

Streets, sidewalks, parking areas, plazas, and other paved surfaces cover large portions of urban areas. These urban hardscapes contribute significantly to cities’ resource consumption. Although urban hardscapes enable people and goods to move freely, they also have profound impacts on cities’ water, air quality, energy, and material use. Reducing the environmental impacts of hardscapes will be an important component of making cities more sustainable. The necessary first step is to quantify those impacts.

UC Davis and Tongji University researchers developed a methodology that combines urban metabolism and life cycle assessment to examine the life cycle impacts of hardscapes at the urban scale rather than at the product or project scale. Urban metabolism (UM) is a method that accounts for the flow of resources such as energy, materials, and water into an urban area, their processing and consumption within the urban area, and their subsequent flows out of the area. Life cycle assessment (LCA) is a quantitative environmental assessment method that considers the total supply chain and life cycle impacts of a product or system from “cradle to grave.”

View the NCST Project Webpage

    Cover page: A Combined Urban Metabolism and Life Cycle Assessment Approach to Improve the Sustainability of Urban Hardscapes
    • Article
    White Papers (2018)

    Urban hardscapes can be defined as human-altered surfaces in contact with the earth in urban areas other than alterations for horticulture. Hardscape covers large portions of the urban surface area, and has potentially large influence on air emissions, truck traffic and its associated problems, and the potential for flooding. Modeling the inflows of hardscape materials and the outflows of demolished hardscape and other rock-based products from buildings and other civil infrastructure is expected to provide a means to find solutions for reducing these flows and their impacts. Modeling of urban hydrology with respect to the effects of hardscape on surface and groundwater flows from precipitation is expected to provide a means to find solutions that will reduce the risk of flooding and improve groundwater recharge.

    The goal of this white paper is to advocate that researchers and policy-makers use the analytical approach of combining urban (UM), material flow analysis (MFA) and elements of life cycle assessment (LCA) to measure and improve the efficiency of urban hardscape in large urbanized areas with respect to environmental impacts affecting global warming, safety and quality of life through use of alternative hardscape structure and materials and more permeable hardscape. The white paper provides details on the proposed UM-LCA framework. Additionally, several data sources and modeling tools were identified that can be used in the UM-LCA framework to quantify material and energy flows and environmental impacts including water flows. An effort was also made to identify data for a few of the cities in California in order to demonstrate parts of the data collection and presentation process. The framework developed is not limited to a single U.S. state, rather it can be used in any geographic region of the U.S.

    View the NCST Project Webpage

      Cover page: Framework for Urban Metabolism and Life Cycle Assessment of Hardscape
      • Article
      • Peer Reviewed
      UC Davis Previously Published Works (2020)

      Objective

      Examine whether cognitive reserve moderates the association of 1) vascular risk factors and 2) white matter hyperintensity burden with risk of clinical progression and longitudinal cognitive decline.

      Methods

      BIOCARD Study participants were cognitively normal and primarily middle-aged (M = 57 years) at baseline and have been followed with annual cognitive and clinical assessments (M = 13 years). Baseline cognitive reserve was indexed with a composite score combining education with reading and vocabulary scores. Baseline vascular risk (N = 229) was assessed with a composite risk score reflecting five vascular risk factors. Baseline white matter hyperintensity load (N = 271) was measured with FLAIR magnetic resonance imaging. Cox regression models assessed risk of progression from normal cognition to onset of clinical symptoms of Mild Cognitive Impairment. Longitudinal mixed effects models measured the relationship of these variables to cognitive decline, using a global composite score, and executive function and episodic memory sub-scores.

      Results

      Both vascular risk and white matter hyperintensities were associated with cognitive decline, particularly in executive function. Higher vascular risk, but not white matter hyperintensity burden, was associated with an increased risk of progression to Mild Cognitive Impairment. Higher cognitive reserve was associated with a reduced risk of symptom onset and higher levels of baseline cognition but did not modify the associations between the vascular risk score and white matter hyperintensities with clinical progression or cognitive decline.

      Interpretation

      Although cognitive reserve has protective effects on clinical and cognitive outcomes, it does not mitigate the negative impact of vascular risk and small vessel cerebrovascular disease on these same outcomes.
        Cover page: Cognitive reserve and midlife vascular risk: Cognitive and clinical outcomes
        • Article
        • Peer Reviewed
        UC Davis Previously Published Works (2020)
        We examined whether cognitive reserve (CR) impacts level of, or rate of change in, biomarkers of Alzheimer's disease (AD) and small-vessel cerebrovascular disease in >250 individuals who were cognitively normal and middle-aged and older at the baseline. The four primary biomarker categories commonly examined in studies of AD were measured longitudinally: cerebrospinal fluid measures of amyloid (A) and tau (T); cerebrospinal fluid and neuroimaging measures of neuronal injury (N); and neuroimaging measures of white matter hyperintensities (WMHs) to assess cerebrovascular pathology (V). CR was indexed by a composite score including years of education, reading, and vocabulary test performance. Higher CR was associated with lower levels of WMHs, particularly among those who subsequently progressed from normal cognition to MCI. CR was not associated with WMH trajectories. In addition, CR was not associated with either levels of, or rate of change in, A/T/N biomarkers. This may suggest that higher CR is associated with lifestyle factors that reduce levels of cerebrovascular disease, allowing individuals with higher CR to better tolerate other types of pathology.
          Cover page: Cognitive reserve and rate of change in Alzheimer's and cerebrovascular disease biomarkers among cognitively normal individuals
          • Article
          • Peer Reviewed
          UC Berkeley Previously Published Works (2024)
          BACKGROUND: There are ≈5 million annual dizziness visits to US emergency departments, of which vestibular strokes account for over 250 000. The head impulse, nystagmus, and test of skew eye examination can accurately distinguish vestibular strokes from peripheral dizziness. However, the eye-movement signs are subtle, and lack of familiarity and difficulty with recognition of abnormal eye movements are significant barriers to widespread emergency department use. To break this barrier, we sought to assess the accuracy of EyePhone, our smartphone eye-tracking application, for quantifying nystagmus. METHODS AND RESULTS: We prospectively enrolled healthy volunteers and recorded the velocity of induced nystagmus using a smartphone eye-tracking application (EyePhone) and then compared the results with video oculography (VOG). Following a calibration protocol, the participants viewed optokinetic stimuli with incremental velocities (2-12 degrees/s) in 4 directions. We extracted slow phase velocities from EyePhone data in each direction and compared them with the corresponding slow phase velocities obtained by the VOG. Furthermore, we calculated the area under the receiver operating characteristic curve for nystagmus detection by EyePhone. We enrolled 10 volunteers (90% men) with an average age of 30.2±6 years. EyePhone-recorded slow phase velocities highly correlated with the VOG recordings (r=0.98 for horizontal and r=0.94 for vertical). The calibration significantly increased the slope of linear regression for horizontal and vertical slow phase velocities. Evaluating the EyePhones performance using VOG data with a 2 degrees/s threshold showed an area under the receiver operating characteristic curve of 0.87 for horizontal and vertical nystagmus detection. CONCLUSIONS: We demonstrated that EyePhone could accurately detect and quantify optokinetic nystagmus, similar to the VOG goggles.
            Cover page: Quantifying Induced Nystagmus Using a Smartphone Eye Tracking Application (EyePhone).
            • Article
            • Peer Reviewed
            UC Davis Previously Published Works (2020)

            Objective

            Recent studies suggest that white matter hyperintensities (WMH) on MRI, which primarily reflect small vessel cerebrovascular disease, may play a role in the evolution of Alzheimer disease (AD). In a longitudinal study, we investigated whether WMH promote the progression of AD pathology, or alter the association between AD pathology and risk of progression from normal cognition to mild cognitive impairment (MCI).

            Methods

            Two sets of analyses were conducted. The relationship between whole brain WMH load, based on fluid-attenuated inversion recovery MRI, obtained in initially cognitively normal participants (n = 274) and time to onset of symptoms of MCI (n = 60) was examined using Cox regression models. In a subset of the participants with both MRI and CSF data (n = 204), the interaction of WMH load and CSF AD biomarkers was also evaluated.

            Results

            Baseline WMH load interacted with CSF total tau (t-tau) with respect to symptom onset, but not with CSF β-amyloid 1-42 or phosphorylated tau (p-tau) 181. WMH volume was associated with time to symptom onset of MCI among individuals with low t-tau (hazard ratio [HR] 1.35, confidence interval [CI] 1.06-1.73, p = 0.013), but not those with high t-tau (HR 0.86, CI 0.56-1.32, p = 0.47). The rate of change in the CSF biomarkers over time was not associated with the rate of change in WMH volumes.

            Conclusion

            These results suggest that WMH primarily affect the risk of progression when CSF measures of neurodegeneration or neuronal injury (as reflected by t-tau) are low. However, CSF biomarkers of amyloid and p-tau and WMH appear to have largely independent and nonsynergistic effects on the risk of progression to MCI.
              Cover page: White matter hyperintensities and CSF Alzheimer disease biomarkers in preclinical Alzheimer disease.
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