124 research outputs found

    Specular: Towards Trust-minimized Blockchain Execution Scalability with EVM-native Fraud Proofs

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    An optimistic rollup (ORU) enables refereed delegation of computation from a blockchain (L1) to an untrusted remote system (L2), by allowing state updates posted on-chain to be disputed by any party via an interactive fraud proof (IFP) protocol. Existing systems that utilize this technique have demonstrated up to a 20x reduction in transaction fees. The most popular ORUs today, in active development, strive to extend existing Ethereum client software to support IFP construction, aiming to reuse prior L1 engineering efforts and replicate Ethereum Virtual Machine (EVM) semantics at L2. Unfortunately, to do so they tightly couple their on-chain IFP verifier with a specific client program binary--oblivious to its higher-level semantics. We argue that this approach (1) precludes the trust-minimized, permissionless participation of multiple Ethereum client programs, magnifying monoculture failure risk; (2) leads to an unnecessarily large and complex trusted computing base that is difficult to independently audit; and, (3) suffers from a frequently-triggered, yet opaque upgrade process--both further increasing auditing overhead and complicating on-chain access control. In this work, we aim to build a secure, trust-minimized ORU that addresses these problems, while preserving scalability and dispute resolution efficiency. To do so, we design an IFP system native to the EVM, that enforces Ethereum's specified semantics precisely at the level of a single EVM instruction. We present Specular, an ORU which leverages an off-the-shelf Ethereum client--modified minimally to support IFP construction--demonstrating the practicality of our approach

    Partner support in a cohort of African American families and its influence on pregnancy outcomes and prenatal health behaviors

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    Abstract Background We examined how two indicators of partner involvement, relationship type and paternal support, influenced the risk of pregnancy outcomes (preterm birth, low birth weight) and health behaviors (prenatal care, drug use, and smoking) among African American women. Methods Interview and medical record data were obtained from a study of 713 adult African American women delivering singletons between March 2001 and July 2004. Women were enrolled prenatally if they received care at one of three Johns Hopkins Medical Institution (JHMI) prenatal clinics or post-partum if they delivered at JHMI with late, no or intermittent prenatal care. Relationship type was classified as married, unmarried/cohabitating, or unmarried/non-cohabitating. Partner support was assessed using an 8-item scale and was dichotomized at the median. Differences in partner support by pregnancy outcome and health behaviors were assessed using linear regression. To assess measures of partner support as predictors of adverse pregnancy outcomes and health behaviors, Poisson regression was used to generate crude and adjusted prevalence ratios (PR) and 95% confidence intervals (CI). Results There were no statistically significant differences in pregnancy outcomes or health behaviors by relationship type or when partner support was examined as a continuous or categorical variable. Modeled as a dichotomous variable, partner support was not associated with the risk of preterm birth (PR = 0.81, 95% CI = 0.56, 1.56), low birth weight (PR = 0.77, 96% CI = 0.48, 1.26), or health behaviors. Conclusions Paternal involvement was not associated with pregnancy outcomes or maternal health behaviors. Attention to measurement issues and other factors relevant for African American women are discussed.http://deepblue.lib.umich.edu/bitstream/2027.42/112953/1/12884_2013_Article_844.pd

    Social mobility and perinatal depression in Black women

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    BackgroundHigher socioeconomic position is associated with better birth outcomes and maternal mental health, although this relationship is less consistent for Black women. The literature is limited on the impact of social mobility across the life course on mental health of pregnant women. This study examines the impact of perceived financial status across the life-course on depressive symptoms during pregnancy among Black women.MethodsData were from the Life-course Influences of Fetal Environments (LIFE) retrospective cohort study among pregnant Black women in metropolitan Detroit, Michigan. Depressive symptoms in the two weeks prior to birth were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Social mobility was determined at three intervals over the life course using self-report of financial status during childhood, adolescence, and current age in pregnancy.Results1,410 pregnant women participated, ranging in age from 18 to 45 years old. CES-D scores ranged from 0 to 53 (mean = 15.3) and 26% of the sample reported high depressive symptoms. In each age interval, higher financial status was associated with significant protective effect on depressive symptoms, and the magnitude of the effect increased across the life course. Trajectory analysis demonstrated that both the upward (4.51; 95% CI, 2.43–6.6) and downward (4.04; 95% CI, 2.62–5.46 and 3.09; 95% CI, 1.57–4.62) life-course social mobility groups had increased mean CES-D scores compared to the static social mobility group.ConclusionThis study describes the importance of previous childhood and current financial status effects on mental health in Black pregnant women

    Partner support in a cohort of African American families and its influence on pregnancy outcomes and prenatal health behaviors

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    Abstract Background We examined how two indicators of partner involvement, relationship type and paternal support, influenced the risk of pregnancy outcomes (preterm birth, low birth weight) and health behaviors (prenatal care, drug use, and smoking) among African American women. Methods Interview and medical record data were obtained from a study of 713 adult African American women delivering singletons between March 2001 and July 2004. Women were enrolled prenatally if they received care at one of three Johns Hopkins Medical Institution (JHMI) prenatal clinics or post-partum if they delivered at JHMI with late, no or intermittent prenatal care. Relationship type was classified as married, unmarried/cohabitating, or unmarried/non-cohabitating. Partner support was assessed using an 8-item scale and was dichotomized at the median. Differences in partner support by pregnancy outcome and health behaviors were assessed using linear regression. To assess measures of partner support as predictors of adverse pregnancy outcomes and health behaviors, Poisson regression was used to generate crude and adjusted prevalence ratios (PR) and 95% confidence intervals (CI). Results There were no statistically significant differences in pregnancy outcomes or health behaviors by relationship type or when partner support was examined as a continuous or categorical variable. Modeled as a dichotomous variable, partner support was not associated with the risk of preterm birth (PR = 0.81, 95% CI = 0.56, 1.56), low birth weight (PR = 0.77, 96% CI = 0.48, 1.26), or health behaviors. Conclusions Paternal involvement was not associated with pregnancy outcomes or maternal health behaviors. Attention to measurement issues and other factors relevant for African American women are discussed

    Direct and Proxy Recall of Childhood Socio‐Economic Position and Health

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    Background The utility of proxy reporting within the life course framework has not been adequately assessed; therefore we sought to assess the magnitude and type of agreement that exists between index and proxy reports for bodyweight, health, and socio‐economic position ( SEP ) in childhood. Methods Participants were enrolled as part of an ongoing study of preterm birth in African American women in M etro D etroit. Post‐partum women and their mothers ( n  = 333 pairs) provided retrospective reports about the woman's childhood bodyweight, health, and SEP . Agreement was assessed using kappa, weighted kappa (κ), and intraclass correlation coefficients ( ICC ). Log‐linear models were used to describe the pattern of agreement for ordinal data. Results Birthweight and weight at age 18 was reported with a high level of agreement ( ICC  = 0.86 and 0.71, respectively). Kappa indicated moderate agreement for early and late childhood/adolescent weight. Log‐linear models suggested that there was diagonal agreement plus linear by linear association for early childhood weight and linear by linear association in late childhood/adolescence. Reports of childhood medical problems and hospitalisations had only moderate agreement. Agreement for SEP in both early (κ = 0.14) and late childhood/adolescence (κ = 0.20) was poor. Log‐linear models suggest a linear by linear association, indicating a positive association between the responses. Conclusions Results suggest that proxy reports may be utilised in conjunction with an index report to provide an estimate of the accuracy of report or to more fully capture experiences over the life course. This may be particularly useful when multiple developmental periods are examined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97462/1/ppe12045.pd

    You’re from … where, again? A critical assessment of institutional diversity in the Society for Epidemiologic Research

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    The Society for Epidemiologic Research (SER) has recently taken laudable steps toward increasing diversity, equity, and inclusion within the society, including participation in the annual meeting. In this essay, we argue that there is one critical piece of the diversity and inclusion equation that is, however, overlooked: institution. At the 2019 Annual Meeting, a mere 8 institutions accounted for a disproportionate number of both oral concurrent sessions and symposium speakers. This lack of institutional diversity, unless addressed, will hinder SER’s ability to address other aspects of diversity, equity, and inclusion

    The Impact of Neighborhood Conditions and Psychological Distress on Preterm Birth in African‐American Women

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    ObjectivePrior research suggests that adverse neighborhood conditions are related to preterm birth. One potential pathway by which neighborhood conditions increase the risk for preterm birth is by increasing women’s psychological distress. Our objective was to examine whether psychological distress mediated the relationship between neighborhood conditions and preterm birth.Design and SampleOne hundred and one pregnant African‐American women receiving prenatal care at a medical center in Chicago participated in this cross‐sectional design study.MeasuresWomen completed the self‐report instruments about their perceived neighborhood conditions and psychological distress between 15–26 weeks gestation. Objective measures of the neighborhood were derived using geographic information systems (GIS). Birth data were collected from medical records.ResultsPerceived adverse neighborhood conditions were related to psychological distress: perceived physical disorder (r = .26, p = .01), perceived social disorder (r = .21, p = .03), and perceived crime (r = .30, p = .01). Objective neighborhood conditions were not related to psychological distress. Psychological distress mediated the effects of perceived neighborhood conditions on preterm birth.ConclusionsPsychological distress in the second trimester mediated the effects of perceived, but not objective, neighborhood conditions on preterm birth. If these results are replicable in studies with larger sample sizes, intervention strategies could be implemented at the individual level to reduce psychological distress and improve women’s ability to cope with adverse neighborhood conditions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137507/1/phn12305_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137507/2/phn12305.pd
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