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  1. Warming in the North Atlantic Ocean has been heterogeneous in recent decades, with locations along the eastern United States seaboard (northwestern Atlantic) seeing some of the largest and fastest warming in the last 100 years. In order to provide a longer temporal context for these changes, we are in the process of developing several master shell growth chronologies and associated geochemical records from theMid-Atlantic coast using the shells of the long-lived marine bivalve Arctica islandica. Based on the shell collection locations (shelf regions offOcean City, Maryland in ~ 61 m water depth and Long Island, New York in ~47 mmore »water depth) and shell geochemistry measurements, we will be able to better ascertain hydrographic spatial and temporal variability of subtropical Atlantic water moving northward through time. These findings will be integrated with similar sclerochronology datasets previously published from the Gulf of Maine region and several others from theMid-Atlantic region that are currently being constructed. Collectively, this network of sclerochronology records will allow us to better characterize changes in the northwestern Atlantic and provide hydrographic insights beyond the relatively short instrumental record and evaluate potential dynamical forcings through time.« less
    Free, publicly-accessible full text available April 1, 2023
  2. Turkay, M. Aydin (Ed.)
    Surrogate models are used to map input data to output data when the actual relationship between the two is unknown or computationally expensive to evaluate for several applications, including surface approximation and surrogate-based optimization. Many techniques have been developed for surrogate modeling; however, a systematic method for selecting suitable techniques for an application remains an open challenge. This work compares the performance of eight surrogate modeling techniques for approximating a surface over a set of simulated data. Using the comparison results, we constructed a Random Forest based tool to recommend the appropriate surrogate modeling technique for a given dataset usingmore »attributes calculated only from the available input and output values. The tool identifies the appropriate surrogate modeling techniques for surface approximation with an accuracy of 87% and a precision of 86%. Using the tool for surrogate model form selection enables computational time savings by avoiding expensive trial-and-error selection methods.« less
  3. The geosciences are one of the least diverse disciplines in the United States, despite the field's relevance to livelihoods and local and global economies. Bias, discrimination, and harassment present serious hurdles to diversifying the field. These behaviors persist due to historical structures of exclusion, severe power imbalances, unique challenges associated with geoscientist stereotypes, and a culture of impunity that tolerates exclusionary behaviors and marginalization of scholars from underserved groups. We summarize recent research on exclusionary behaviors that create hostile climates and contribute to persistent low retention of diverse groups in the geosciences and other science, technology, engineering, and mathematics (STEM)more »fields. We then discuss recent initiatives in the US by geoscience professional societies and organizations, including the National Science Foundation-supported ADVANCEGeo Partnership, to improve diversity, equity, and inclusion by improving workplace climate. Social networks and professional organizations can transform scientific culture through providing opportunities for mentorship and community building and counteracting professional isolation that can result from experiencing hostile behaviors, codifying ethical practice, and advocating for policy change. We conclude with a call for a reexamination of current institutional structures, processes, and practices for a transformational and equitable scientific enterprise. To be truly successful, cultural and behavioral changes need to be accompanied by reeducation about the historical political structures of academic institutions to start conversations about the real change that has to happen for a transformational and equitable scientific enterprise.« less
  4. Design and implementation of the first (asymmetric) Fe-catalyzed intra- and intermolecular difunctionalization of vinyl cyclopropanes (VCPs) with alkyl halides and aryl Grignard reagents has been realized via a mechanistically driven approach. Mechanistic studies support the diffusion of the alkyl radical intermediates out of the solvent cage to participate in an intra- or -intermolecular radical cascade with the VCP followed by re-entering the Fe radical cross-coupling cycle to undergo selective C(sp2)-C(sp3) bond formation. Overall, we provide new design principles for Fe-mediated radical processes and underscore the potential of using combined computations and experiments to accelerate the development of challenging transformations.