The western North-Atlantic coast experienced major coastal floods in recent years. Coastal floods are primarily composed of tides and storm surges due to tropical (TCs) and extra-tropical cyclones (ETCs). We present a reanalysis from 1988 to 2015 of extreme sea levels that explicitly include TCs for the western North-Atlantic coastline. Validation shows a good agreement between modeled and observed sea levels and demonstrates that the framework can capture large-scale variability in extreme sea levels. We apply the 28-year reanalysis to analyze spatiotemporal patterns. Along the US Atlantic coasts the contribution of tides can be significant, with the average contribution of tides during the 10 largest events up to 55% in some locations, whereas along the Mexican Southern Gulf coast, the average contribution of tides over the largest 10 events is generally below 25%. At the US Atlantic coast, ETCs are responsible for 8.5 out of the 10 largest extreme events, whereas at the Gulf Coast and Caribbean TCs dominate. During the TC season more TC-driven events exceed a 10-year return period. During winter, there is a peak in ETC-driven events. Future research directions include coupling the framework with synthetic tropical cyclone tracks and extension to the global scale.@en

DNA polymerase catalyzes the accurate transfer of genetic information from one generation to the next, and thus it is vitally important for replication to be faithful. DNA polymerase fulfills the strict requirements for fidelity by a combination of mechanisms: 1) high selectivity for correct nucleotide incorporation, 2) a slowing down of the replication rate after misincorporation, and 3) proofreading by excision of misincorporated bases. To elucidate the kinetic interplay between replication and proofreading, we used high-resolution optical tweezers to probe how DNA-duplex stability affects replication by bacteriophage T7 DNA polymerase. Our data show highly irregular replication dynamics, with frequent pauses and direction reversals as the polymerase cycles through the states that govern the mechanochemistry behind high-fidelity T7 DNA replication. We constructed a kinetic model that incorporates both existing biochemical data and the, to our knowledge, novel states we observed. We fit the model directly to the acquired pause-time and run-time distributions. Our findings indicate that the main pathway for error correction is DNA polymerase dissociation-mediated DNA transfer, followed by biased binding into the exonuclease active site. The number of bases removed by this proofreading mechanism is much larger than the number of erroneous bases that would be expected to be incorporated, ensuring a high-fidelity replication of the bacteriophage T7 genome.

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