Speeding behavior among teenage drivers during the learner and early independent driving stage: A case study approach.

INTRODUCTION: Speed is a primary contributing factor in teenage driver crashes. Yet, there are significant methodological challenges in measuring real-world speeding behavior. METHOD: This case study approach analyzed naturalistic driving data for six teenage drivers in a longitudinal study that spanned the learner and early independent driving stages of licensure in Maryland, United States. Trip duration, travel speed and length were recorded using global position system (GPS) data. These were merged with maps of the Maryland road system, which included posted speed limit (PSL) to determine speeding events in each recorded trip. Speeding was defined as driving at the speed of 10 mph higher than the posted speed limit and lasting longer than 6 s. Using these data, two different speeding measures were developed: (1) Trips with Speeding Episodes, and (2) Verified Speeding Time. Conclusions & Practical Applications: Across both measures, speeding behavior during independent licensure was greater than during the learner period. These measures improved on previous methodologies by using PSL information and eliminating the need for mapping software. This approach can be scaled for use in larger samples and has the potential to advance understanding about the trajectory of speeding behaviors among novice teenage drivers.

Design of an innovative digital application to facilitate access to healthy foods in low-income urban settings.

Background: Under-resourced urban minority communities in the United States are characterized by food environments with low access to healthy foods, high food insecurity, and high rates of diet-related chronic disease. In Baltimore, Maryland, low access to healthy food largely results from a distribution gap between small food sources (retailers) and their suppliers. Digital interventions have the potential to address this gap, while keeping costs low. Methods: In this paper, we describe the technical (I) front-end design and (II) back-end development process of the Baltimore Urban food Distribution (BUD) application (app). We identify and detail four main phases of the process: (I) information architecture; (II) low and high-fidelity wireframes; (III) prototype; and (IV) back-end components, while considering formative research and a pre-pilot test of a preliminary version of the BUD app. Results: Our lessons learned provide valuable insight into developing a stable app with a user-friendly experience and interface, and accessible cloud computing services for advanced technical features. Conclusions: Next steps will involve a pilot trial of the app in Baltimore, and eventually, other urban and rural settings nationwide. Once iterative feedback is incorporated into the app, all code will be made publicly available via an open source repository to encourage adaptation for desired communities. Trial Registration: ClinicalTrials.gov NCT05010018.

The single-cell transcriptomic landscape of the topological differences in mammalian auditory receptors.

Mammalian hair cells (HCs) are arranged spirally along the cochlear axis and correspond to different frequency ranges. Serving as primary sound detectors, HCs spatially segregate component frequencies into a topographical map. HCs display significant diversity in anatomical and physiological characteristics, yet little is known about the organization of the cochleotopic map of HCs or the molecules involved in this process. Using single-cell RNA sequencing, we determined the distinct molecular profiles of inner hair cells and outer hair cells, and we identified numerous position-dependent genes that were expressed as gradients. Newly identified genes such as Ptn, Rxra, and Nfe2l2 were found to be associated with tonotopy. We employed the SCENIC algorithm to predict the transcription factors that potentially shape these tonotopic gradients. Furthermore, we confirmed that Nfe2l2, a tonotopy-related transcription factor, is critical in mice for sensing low-to-medium sound frequencies in vivo. the analysis of cell-cell communication revealed potential receptor-ligand networks linking inner hair cells to spiral ganglion neurons, including pathways such as BDNF-Ntrk and PTN-Scd4, which likely play essential roles in tonotopic maintenance. Overall, these findings suggest that molecular gradients serve as the organizing principle for maintaining the selection of sound frequencies by HCs.