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Traffic congestion is a major problem in large cities worldwide. This project uses high-frequency data from the Los Angeles metropolitan area combined with an instrument that varies spatially and temporally to estimate the causal impact of an additional vehicle mile traveled on travel times. Specifically, the research team exploits the network structure of the Los Angeles highway system and uses crashes on close alternative routes as exogenous shocks to traffic demand. To do so, the team relies on Google Maps to determine the ideal route and alternatives for over 19,000 real-world commutes. The researchers estimate that at peak times an additional trip reduces speed by, on average, 0.22%. They find the optimal toll at peak times is 33 cents per mile, with the toll being lower, even zero, off-peak. The researchers show how this toll varies over space and time, as well as report on its distributional effects. This toll would more than double highway speeds during peak times and only requires reducing vehicle miles traveled (VMT) at the peak by 10%. The resulting social welfare gains are over two billion dollars per year.View the NCST Project Webpage

The shift to student engagement in scientific and engineering practices to learn science provides opportunities for science learning and language learning to occur in tandem. These opportunities also pose new challenges for elementary pre-service teachers (PSTs) since literacy methods courses have been presented separately from science methods courses. We integrated a disciplinary literacy framework in a science methods course to help elementary PSTs understand the synergistic connections between literacy and science teaching. The purpose of this study was to examine elementary PSTs' understanding of the use of science-specific literacy strategies to support science teaching and learning through three points of observation. Findings from three data sources indicated that PSTs showed a developing understanding of the role of disciplinary literacy in supporting student engagement in science practices and learning disciplinary core ideas. Implications for future uses of a disciplinary literacy framework for teaching and learning science and elementary PSTs' science preparation are presented.

This study presents the recollections of 12 successful women in science during their school years before postsecondary education. The participants shared detailed descriptions of their science experiences through three semi-structured interviews. An identity works conceptual framework consisting of figured worlds, positioning, and agency constructs to portray the complex dynamics of their experiences was used to analyze the data. The following four themes emerged from the data analysis: participants had an early interest in mathematics and science; they were "stubbornly" persistent in science-figured worlds; they engaged in science-figured worlds beyond school; and they positioned themselves as science leaders. These findings add to the evolution of science identity development theoretical models because they are from a nondeficit perspective. Participants engaged in identity work that advanced their science identities despite the gender biases in science-figured worlds. From a practical stance, girls and women could employ the agentic and positive positioning identity work that the findings show to develop their science identity in educational contexts. Science educators and researchers are encouraged to structure figured worlds where girls feel empowered to enact identity work to build strong science identities.

The automotive industry must mitigate climate change by reducing vehicle carbon emissions and promoting sustainable transportation through technical solutions and innovations. Biofuels are seen as a solution to reduce CO2 emissions, but they may affect fuel performance and emissions. Second-generation biogasoline mixed with ethanol has proven that it can be introduced as a drop-in fuel with the same performance and tailpipe emissions at the same level as fossil fuels. However, particulate matter (PM) emissions are significantly higher than fossil fuels. This study aims to experimentally investigate the effect of port and direct fuel injections on the PM emissions in a boosted spark ignition (SI) engine fuelled by Euro 6 standard biofuel with a 99 octane number blended with 20% ethanol compared to a fossil fuel baseline. The single-cylinder SI engine was equipped with two fuel injectors, a direct injector and a port fuel injector, and operated with externally boosted air. The split injection ratio was adjusted from 100% direct injection (DI) to 100% port fuel injection (PFI) to investigate the combustion characteristics and particulate emissions (PM) at different engine loads and speeds. The results indicate that by changing 100% DI to 80% PFI, PM emissions numbers between particle sizes of 23 and 1000 nm were dropped by 96.56% at a low load operation of 4.6 bar IMEP for the 99 RON E20 biogasoline and by 84% for the 95 RON E10 fossil fuel while maintaining the same indicated thermal efficiency and a similar level of other emissions. However, at a higher load above 10 bar IMEP, it was found that full DI operation reduced particulate numbers (PN) by 64% and 38% for 99 RON E20 biogasoline and 95 RON E10 fossil fuel at 20 bar IMEP, respectively, and enabled more stable operation at 3000 rpm with higher load operation regions. [ABSTRACT FROM AUTHOR]

This study assesses the development of proactive control strategies in 100 Syrian refugee families (394 individuals) with 6- to 18-year-old children currently living in Turkish communities. The results demonstrate that children's age and their mothers' post-traumatic stress symptoms were associated with the degree of proactive control in their children, with worse mental health being associated with a larger reliance on reactive control and lesser reliance on proactive, future-oriented, control (measured via d′ in the AX-CPT task). None of the following factors contributed to children's performance: fathers' experience with post-traumatic stress, parents' exposure to potentially traumatic war-related events, perceived discrimination, a decline in socio-economic status, religious beliefs, parents' proactive control strategies, or the education or gender of the children themselves. The association between mothers' mental health and proactive control strategies in children was large (in terms of effect size), suggesting that supporting mothers' mental health might have clear effects on the development of their children. [ABSTRACT FROM AUTHOR]