4,918 research outputs found

    Pumping the Brakes on Robot Cars: Current Urban Traveler Willingness to Consider Driverless Vehicles

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    A growing literature suggests that widespread travel conducted through driverless connected and automated vehicles (CAVs) accessed as a service, in contrast to those personally owned, could have significant impacts on the sustainability of urban transportation. However, it is unclear how the general public currently considers willingness to travel in driverless vehicles, and if they would be more comfortable doing so in one personally owned or one accessed as a service. To address this, we collected travel survey data by intercepting respondents on discretionary or social trips to four popular destinations in a medium-size U.S. city in the spring of 2017. After collecting data on how the respondent reached the survey site and the trip’s origin and destination, survey administrators then asked if respondents would have been willing to make their current trip in either a personally-owned driverless vehicle or through a driverless vehicle service. Over one-third expressed willingness to use both forms, while 31% were unwilling to use either. For those that considered only one, slightly more favored the personally-owned model. Consideration of an existing mobility service was consistently a positive and significant predictor of those that expressed willingness to travel in a driverless vehicle, while traveling downtown negatively and significantly influenced consideration of at least one form of driverless vehicle. These findings highlight the diverse public views about the prospect of integration of CAVs in transportation systems and raise questions about the assumption that travelers to central city locations would be early adopters of automated vehicle mobility services.The research reported here was supported in part by the U.S. Environmental Protection Agency (EPA), SPEED Program Grant No. 83594901the University of Michigan Energy Institute (UMEI) and University of Michigan Dow Sustainability Fellows progra

    Survival after bidirectional cavopulmonary anastomosis: Analysis of preoperative risk factors

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    ObjectivePrognostic factors for survival after bidirectional cavopulmonary anastomosis for functionally single ventricle are not well defined. We analyzed preoperative hemodynamic and echocardiographic data to determine risk factors for death or transplantation at least 1 year after bidirectional cavopulmonary anastomosis.MethodsData for all patients who underwent bidirectional cavopulmonary anastomosis before 5 years of age at our institution from September 1995 through June 2005 were analyzed. Available preoperative echocardiograms and catheterizations were reviewed. Survivors were compared with those who died or underwent transplantation. Bivariable associations between demographic and clinical risk factors and survival status (alive without transplantation vs dead or transplanted) were assessed with Wilcoxon rank sum test and χ2 or Fisher exact tests. Survival functions were constructed with Kaplan–Meier estimates, and event times compared between subgroups with log–rank tests. Cox proportional hazard modeling was used for multivariable modeling of risk of death or transplantation.ResultsOne hundred sixty-seven patients underwent bidirectional cavopulmonary anastomosis with hemi-Fontan (n = 62) or bidirectional Glenn (n = 105) operations. Three patients died before discharge, 11 died later, and 1 has undergone transplantation. Freedom from death or transplantation after bidirectional cavopulmonary anastomosis was 96% at 1 year and 89% at 5 years. Multivariable analysis of preoperative variables showed atrioventricular valve regurgitation to be an independent risk factor for death or transplantation (hazard ratio 2.8, 95% confidence interval 1.1–7.1, P = .02).ConclusionAlthough survival after bidirectional cavopulmonary anastomosis is high, preoperative atrioventricular valve regurgitation is an important risk factor for death or transplantation

    Comparative biochemical analysis of UHRF proteins reveals molecular mechanisms that uncouple UHRF2 from DNA methylation maintenance

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    UHRF1 is a histone- and DNA-binding E3 ubiquitin ligase that functions with DNMT1 to maintain mammalian DNA methylation. UHRF1 facilitates DNMT1 recruitment to replicating chromatin through a coordinated mechanism involving histone and DNA recognition and histone ubiquitination. UHRF2 shares structural homology with UHRF1, but surprisingly lacks functional redundancy to facilitate DNA methylation maintenance. Molecular mechanisms uncoupling UHRF2 from DNA methylation maintenance are poorly defined. Through comprehensive and comparative biochemical analysis of recombinant human UHRF1 and UHRF2 reader and writer activities, we reveal conserved modes of histone PTM recognition but divergent DNA binding properties. While UHRF1 and UHRF2 diverge in their affinities toward hemi-methylated DNA, we surprisingly show that both hemi-methylated and hemi-hydroxymethylated DNA oligonucleotides stimulate UHRF2 ubiquitin ligase activity toward histone H3 peptide substrates. This is the first example of an E3 ligase allosterically regulated by DNA hydroxymethylation. However, UHRF2 is not a productive histone E3 ligase toward purified mononucleosomes, suggesting UHRF2 has an intra-domain architecture distinct from UHRF1 that is conformationally constrained when bound to chromatin. Collectively, our studies reveal that uncoupling of UHRF2 from the DNA methylation maintenance program is linked to differences in the molecular readout of chromatin signatures that connect UHRF1 to ubiquitination of histone H3

    Period-1 Encodes an ATP-Dependent RNA Helicase that Influences Nutritional Compensation of the Neurospora Circadian Clock

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    Mutants in the period-1 (prd-1) gene, characterized by a recessive allele, display a reduced growth rate and period lengthening of the developmental cycle controlled by the circadian clock. We refined the genetic location of prd-1 and used whole genome sequencing to find the mutation defining it, confirming the identity of prd-1 by rescuing the mutant circadian phenotype via transformation. PRD-1 is an RNA helicase whose orthologs, DDX5 [DEAD (Asp-Glu-Ala-Asp) Box Helicase 5] and DDX17 in humans and DBP2 (Dead Box Protein 2) in yeast, are implicated in various processes, including transcriptional regulation, elongation, and termination, ribosome biogenesis, and mRNA decay. Although prd-1 mutants display a long period (∼25 h) circadian developmental cycle, they interestingly display a WT period when the core circadian oscillator is tracked using a frq-luciferase transcriptional fusion under conditions of limiting nutritional carbon; the core oscillator in the prd-1 mutant strain runs with a long period under glucose-sufficient conditions. Thus, PRD-1 clearly impacts the circadian oscillator and is not only part of a metabolic oscillator ancillary to the core clock. PRD-1 is an essential protein, and its expression is neither light-regulated nor clock-regulated. However, it is transiently induced by glucose; in the presence of sufficient glucose, PRD-1 is in the nucleus until glucose runs out, which elicits its disappearance from the nucleus. Because circadian period length is carbon concentration-dependent, prd-1 may be formally viewed as a clock mutant with defective nutritional compensation of circadian period length

    Primary Language Spoken at Home and Children\u27s Dental Service Utilization in the United States

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    Objective: Language barriers have been well documented as a contributing factor to disparities in the receipt of medical services, especially for Hispanic children. However, there is a paucity of information on the effect of language barriers on children\u27s dental service utilization. We examined the association of primary language spoken at home with the receipt of preventive and routine dental care for children in the United States. Methods: We analyzed data from the Medical Expenditure Panel Survey (2002-2004), which contains data on 21,049 children weighted to represent 75.8 million children nationally. Results: Among children aged 1-18 years, 13 percent spoke a language other than English at home. Whites, females, children between the ages of 7 and 12 years, and those whose parents spoke English at home had the highest marginal rates of preventive and routine dental visits. However, the large marginal effect of language, even among Hispanics, was not significant after adjusting for other covariates. Parental education and having a primary provider were the strongest predictors of preventive and routine dental visits. Conclusion: Children that did not speak English at home were less likely to receive preventive or routine dental care. However, after adjusting for other socio-economic factors, our study suggests that language barriers may not play as pronounced a role in the receipt of dental care as that documented for medical services
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