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Open Access Publications from the University of California

Scholarly Works (9 results)

  • Article
  • Peer Reviewed
American Indian Culture and Research Journal , Volume 32, Issue 3 (2008)
The map is a primary tool in geographic research, and the discipline of geography has experienced a significant methodological transformation during the last three decades with the development and now near ubiquity of geographic information systems (GIS) technology. The introduction of this technology into Indian country has spurred a debate over the appropriateness and effectiveness of using GIS for Native mapping purposes. In this article, I review issues concerning the use of GIS in Native communities and present a case study of one particular tribe’s implementation of the technology. GIS are computer systems designed to store, manipulate, and portray spatial data, theoretically making analysis of such data easier, faster, and more powerful. However, many in the geographic community view GIS as a “contradictory technology that can both empower and marginalize people and communities.” At the same time that broader debates about the social impacts of GIS, public-participation or community-based GIS, and GIS and society developed in urban geographic research, so did a more focused debate centered around GIS and Indigenous peoples. INDIGENOUS GEOGRAPHY AND GIS Major concerns that have been raised about the uncritical use of GIS in Native communities include perpetuation of established power relations through use of the technology, incompatibility between Native geographical knowledge systems and Western cartographic techniques inherent to GIS, and risks associated with storing Indigenous knowledge in digital form. Other concerns are more methodological in nature and include issues of cost and accessibility. First, in the United States, the Bureau of Indian Affairs (BIA) has been instrumental in introducing GIS technology to many reservations. As Rundstrom, Deur, Berry, and Winchell point out, some tribes have curtailed BIA access to their databases because of a deep-seated suspicion of the agency and its historically assimilationist tendencies.
    Cover page: Indigenous Geography, GIS, and Land-Use Planning on the Bois Forte ReservationCreative Commons 'BY-NC' version 4.0 license
    • Thesis
    • Peer Reviewed
    UCLA Electronic Theses and Dissertations (2012)

    The spatial features within a region influence many processes in human activity. Mountains, lakes, oceans, rivers, freeways, population densities, housing densities, and road networks are examples of geographical factors that impact spatial behaviors. Separated into two parts, the work presented here incorporates this information into both density estimation methods and models of street gang rivalries and territories.

    Part I discusses methods for producing a probability density estimate given a set of discrete event data. Common methods of density estimation, such as Kernel Density Estimation, do not incorporate geographical information. Using these methods could result in non-negligible portions of the support of the density in unrealistic geographic locations. For example, crime density estimation models that do not take geographic information into account may predict events in unlikely places such as oceans, mountains, etc. To obtain more geographically accurate density estimates, a set of Maximum Penalized Likelihood Estimation methods based on Total Variation norm and H1 Sobolev semi-norm regularizers in conjunction with a priori high resolution spatial data is proposed. These methods are applied to a residential burglary data set of the San Fernando Valley using geographic features obtained from satellite images of the region and housing density information.

    Part II addresses the behaviors and rivalries of street gangs and how the spatial characteristics of the region affect the dynamics of the system. Gangs typically claim a specific territory as their own, and they tend to have a set space, a location they use as a center for their activities within the territory. The spatial distribution of gangs influences the rivalries that develop within the area. One stochastic model and one deterministic model are proposed, providing different types of outputs. Both models incorporate important geographical features from the region that would inhibit movement, such as rivers and large highways. In the stochastic method, an agent-based model simulates the creation of street gang rivalries. The movement dynamics of agents are coupled to an evolving network of gang rivalries, which is determined by previous interactions among agents in the system. Basic gang data, geographic information, and behavioral dynamics suggested by the criminology literature are integrated into the model. The deterministic method, derived from a stochastic approach, modifies a system of partial differential equations from a model for coyotes. Territorial animals and street gangs often exhibit similar behavioral characteristics. Both groups have a home base and mark their territories to distinguish claimed regions. To analyze the two methods, the Hollenbeck policing division of the Los Angeles Police Department is used as a case study.

      Cover page: Incorporating Spatial Information into Density Estimates and Street Gang Models
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2022)

      Background

      The prevalence and risk factors for residual neuromuscular blockade in children remain poorly characterized. We hypothesize that specific patient and anesthetic risk factors may be associated with the administration of additional reversal in children following initial reversal of rocuronium with neostigmine.

      Methods

      Our electronic health record was queried for patients <18 years of age who received rocuronium and reversal with neostigmine from 2017 through 2020. Patients receiving other nondepolarizing neuromuscular blocking drugs were excluded. The outcome of interest was defined as the administration of additional neostigmine or sugammadex following primary reversal with neostigmine. Time between the last dose of rocuronium and initial dose of neostigmine, and the cumulative dose of rocuronium were dichotomized. These were combined with other covariates including age, weight, sex, racial group, procedure type, ASA physical status, >1 rocuronium dose administered during the procedure, initial neostigmine dose <0.05 mg kg-1 , use of train-of-four monitoring, duration of anesthesia, inpatient or outpatient, emergency case, neuromuscular disease, and extremes of weight, to assess possible associations with the primary outcome.

      Results

      During the study period, 101/6373 (1.58%) patients received rocuronium and additional reversal. Dichotomization of time between last dose of rocuronium and neostigmine yielded <28 min since the last dose of rocuronium and cumulative dose of rocuronium >0.45 mg kg-1  hr-1 . These were associated with the administration of additional reversal with an OR 1.52 (95% CI, 1.08-2.35) and OR 1.71 (95% CI, 1.10-2.67), respectively. Other risk factors included an initial neostigmine dose <0.05 mg kg-1 , OR 4.98 (95% CI, 2.84-6.49), and African American race, OR 1.78 (95% CI, 1.07-2.87).

      Conclusion

      Risk factors associated with the administration of additional reversal included time <28 min from the last dose of rocuronium to initial dose of neostigmine, cumulative dose of rocuronium >0.45 mg kg-1  hr-1 , initial neostigmine dose <0.05 mg kg-1 , and African American race.
        Cover page: Risk factors for administration of additional reversal following neuromuscular blockade with rocuronium in children: A retrospective case–control study
        • Article
        • Peer Reviewed
        UCLA Previously Published Works (2018)
        Community partnered participatory research (CPPR) emphasizes community engagement, respect, and empowerment as guiding principles to promote mental health equity. This article describes the "Vision" stage of a CPPR-informed model to implement evidence-based practices for depression in two African American churches in Harlem, New York. Essential parts of the Vision include engagement of stakeholders and collaborative planning. The engagement process increased awareness about the project via a community-focused mental health symposium. The collaborative planning stage resulted in creating a multi-disciplinary Community Coalition for Mental Health, establishing the Coalition's values, agreeing to change the initial chosen study intervention from Interpersonal Counseling to Mental Health First Aid, and developing a website to disseminate the group's work. Key lessons learned from our partnered process are: 1) support from the lead pastor is crucial; 2) balancing community and academic interests can be challenging; 3) icebreaker activities foster relationships and reinforce CPPR principles; 4) multiple communication channels can enhance community participation; and, 5) should organize data in ways that make them easier to interpret.
          Cover page: Partnering with African American Churches to Create a Community Coalition for Mental Health.
          • Article
          • Peer Reviewed
          UC Davis Previously Published Works (2017)
          The association between obesity and breast cancer risk and prognosis is well established in estrogen receptor (ER)-positive disease but less clear in HER2-positive disease. Here, we report preclinical evidence suggesting weight maintenance through calorie restriction (CR) may limit risk of HER2-positive breast cancer. In female MMTV-HER2/neu transgenic mice, we found that ERα and ERβ expression, mammary tumorigenesis, and survival are energy balance dependent in association with epigenetic reprogramming. Mice were randomized to receive a CR, overweight-inducing, or diet-induced obesity regimen (n = 27/group). Subsets of mice (n = 4/group/time point) were euthanized after 1, 3, and 5 months to characterize diet-dependent metabolic, transcriptional, and epigenetic perturbations. Remaining mice were followed up to 22 months. Relative to the overweight and diet-induced obesity regimens, CR decreased body weight, adiposity, and serum metabolic hormones as expected and also elicited an increase in mammary ERα and ERβ expression. Increased DNA methylation accompanied this pattern, particularly at CpG dinucleotides located within binding or flanking regions for the transcriptional regulator CCCTC-binding factor of ESR1 and ESR2, consistent with sustained transcriptional activation of ERα and ERβ. Mammary expression of the DNA methylation enzyme DNMT1 was stable in CR mice but increased over time in overweight and diet-induced obesity mice, suggesting CR obviates epigenetic alterations concurrent with chronic excess energy intake. In the survival study, CR elicited a significant suppression in spontaneous mammary tumorigenesis. Overall, our findings suggest a mechanistic rationale to prevent or reverse excess body weight as a strategy to reduce HER2-positive breast cancer risk. Cancer Res; 77(9); 2500-11. ©2017 AACR.
            • Article
            • Peer Reviewed
            UCLA Previously Published Works (2007)

            Background

            Restriction landmark genomic scanning (RLGS) is one of the most successfully applied methods for the identification of aberrant CpG island hypermethylation in cancer, as well as the identification of tissue specific methylation of CpG islands. However, a limitation to the utility of this method has been the ability to assign specific genomic sequences to RLGS spots, a process commonly referred to as "RLGS spot cloning."

            Results

            We report the development of a virtual RLGS method (vRLGS) that allows for RLGS spot identification in any sequenced genome and with any enzyme combination. We report significant improvements in predicting DNA fragment migration patterns by incorporating sequence information into the migration models, and demonstrate a median Euclidian distance between actual and predicted spot migration of 0.18 centimeters for the most complex human RLGS pattern. We report the confirmed identification of 795 human and 530 mouse RLGS spots for the most commonly used enzyme combinations. We also developed a method to filter the virtual spots to reduce the number of extra spots seen on a virtual profile for both the mouse and human genomes. We demonstrate use of this filter to simplify spot cloning and to assist in the identification of spots exhibiting tissue-specific methylation.

            Conclusion

            The new vRLGS system reported here is highly robust for the identification of novel RLGS spots. The migration models developed are not specific to the genome being studied or the enzyme combination being used, making this tool broadly applicable. The identification of hundreds of mouse and human RLGS spot loci confirms the strong bias of RLGS studies to focus on CpG islands and provides a valuable resource to rapidly study their methylation.
              Cover page: Restriction Landmark Genomic Scanning (RLGS) spot identification by second generation virtual RLGS in multiple genomes with multiple enzyme combinations
              • Article
              • Peer Reviewed
              UC Berkeley Previously Published Works (2021)

              Background

              Small-quantity lipid-based nutrient supplements (SQ-LNSs) have been shown to reduce the prevalence of child anemia and iron deficiency, but effects on other micronutrients are less well known. Identifying subgroups who benefit most from SQ-LNSs could support improved program design.

              Objectives

              We aimed to identify study-level and individual-level modifiers of the effect of SQ-LNSs on child hemoglobin (Hb), anemia, and inflammation-adjusted micronutrient status outcomes.

              Methods

              We conducted a 2-stage meta-analysis of individual participant data from 13 randomized controlled trials of SQ-LNSs provided to children 6-24 mo of age (n = 15,946). We generated study-specific and subgroup estimates of SQ-LNSs compared with control, and pooled the estimates using fixed-effects models. We used random-effects meta-regression to examine potential study-level effect modifiers.

              Results

              SQ-LNS provision decreased the prevalence of anemia (Hb < 110 g/L) by 16% (relative reduction), iron deficiency (plasma ferritin < 12 µg/L) by 56%, and iron deficiency anemia (IDA; Hb < 110 g/L and plasma ferritin <12 µg/L) by 64%. We observed positive effects of SQ-LNSs on hematological and iron status outcomes within all subgroups of the study- and individual-level effect modifiers, but effects were larger in certain subgroups. For example, effects of SQ-LNSs on anemia and iron status were greater in trials that provided SQ-LNSs for >12 mo and provided 9 (as opposed to <9) mg Fe/d, and among later-born (than among first-born) children. There was no effect of SQ-LNSs on plasma zinc or retinol, but there was a 7% increase in plasma retinol-binding protein (RBP) and a 56% reduction in vitamin A deficiency (RBP < 0.70 µmol/L), with little evidence of effect modification by individual-level characteristics.

              Conclusions

              SQ-LNSs can substantially reduce the prevalence of anemia, iron deficiency, and IDA among children across a range of individual, population, and study design characteristics. Policy-makers and program planners should consider SQ-LNSs within intervention packages to prevent anemia and iron deficiency.This trial was registered at www.crd.york.ac.uk/PROSPERO as CRD42020156663.
                Cover page: Characteristics that modify the effect of small-quantity lipid-based nutrient supplementation on child anemia and micronutrient status: an individual participant data meta-analysis of randomized controlled trials.
                • Article
                • Peer Reviewed
                UC Davis Previously Published Works (2021)

                ABSTRACT

                Background

                Small-quantity lipid-based nutrient supplements (SQ-LNS) have been shown to reduce the prevalence of anemia and iron deficiency among infants and young children, but effects on other micronutrients are less well known. Identifying subgroups who may experience greater benefits from SQ-LNS, or who are more likely to respond to the intervention, may facilitate the development of public health policies and programs.

                Objective

                Our objective was to identify study-level and individual-level modifiers of the effect of SQ-LNS on child hematological and micronutrient status outcomes.

                Methods

                We conducted a two-stage meta-analysis of individual participant data from 13 randomized controlled trials of SQ-LNS provided to children 6 to 24 months of age in low- and middle-income countries (n = 15,946). Outcomes were hemoglobin (Hb), inflammation-adjusted plasma ferritin, soluble transferrin receptor, zinc, retinol and retinol binding protein (RBP), and erythrocyte zinc protoporphyrin, and respective dichotomous outcomes indicative of anemia and micronutrient deficiency. We generated study-specific estimates of SQ-LNS vs. control, including main effects and subgroup estimates for individual-level effect modifiers, and pooled the estimates using fixed-effects models. We used random effects meta-regression to examine potential study-level effect modifiers.

                Results

                Provision of SQ-LNS decreased the prevalence of anemia (Hb < 110 g/L) by 16% (relative reduction), iron deficiency (plasma ferritin < 12 µg/L) by 56% and iron deficiency anemia (IDA; Hb < 110 g/L and plasma ferritin < 12 µg/L) by 64%. We observed positive effects of SQ-LNS on hematological and iron status outcomes within all subgroups of the study-level and individual-level effect modifiers, but effects were larger in certain subgroups. For example, effects of SQ-LNS on anemia and iron status were greater in trials that provided SQ-LNS for > 12 months and provided 9 mg/d vs. < 9 mg iron/d, and among later-born (vs. first-born) children. There was no effect of SQ-LNS on plasma zinc or retinol, but there was a 7% increase in plasma RBP and a 56% reduction in vitamin A deficiency (RBP < 0.70 µmol/L), with little evidence of effect modification by individual-level characteristics.

                Conclusions

                SQ-LNS provided to infants and young children 6-24 months of age can substantially reduce the prevalence of anemia, iron deficiency, and IDA across a range of individual, population and study design characteristics. Policy-makers and program planners should consider SQ-LNS within intervention packages to prevent anemia and iron deficiency. This study was registered at www.crd.york.ac.uk/PROSPERO as CRD42020156663.
                  • Article
                  • Peer Reviewed
                  UC Davis Previously Published Works (2020)
                  Children at increased genetic risk for type 1 diabetes (T1D) after environmental exposures may develop pancreatic islet autoantibodies (IA) at a very young age. Metabolic profile changes over time may imply responses to exposures and signal development of the first IA. Our present research in The Environmental Determinants of Diabetes in the Young (TEDDY) study aimed to identify metabolome-wide signals preceding the first IA against GAD (GADA-first) or against insulin (IAA-first). We profiled metabolomes by mass spectrometry from children's plasma at 3-month intervals after birth until appearance of the first IA. A trajectory analysis discovered each first IA preceded by reduced amino acid proline and branched-chain amino acids (BCAAs), respectively. With independent time point analysis following birth, we discovered dehydroascorbic acid (DHAA) contributing to the risk of each first IA, and γ-aminobutyric acid (GABAs) associated with the first autoantibody against insulin (IAA-first). Methionine and alanine, compounds produced in BCAA metabolism and fatty acids, also preceded IA at different time points. Unsaturated triglycerides and phosphatidylethanolamines decreased in abundance before appearance of either autoantibody. Our findings suggest that IAA-first and GADA-first are heralded by different patterns of DHAA, GABA, multiple amino acids, and fatty acids, which may be important to primary prevention of T1D.
                    Cover page: Longitudinal Metabolome-Wide Signals Prior to the Appearance of a First Islet Autoantibody in Children Participating in the TEDDY Study
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