Search for: All records

The digital alchemy framework is an extended ensemble simulation technique that incorporates particle attributes as thermodynamic variables, enabling the inverse design of colloidal particles for desired behavior. Here, we extend the digital alchemy framework for the inverse design of patchy spheres that self-assemble into target crystal structures. To constrain the potentials to non-trivial solutions, we conduct digital alchemy simulations with constant second virial coefficient. We optimize the size, range, and strength of patchy interactions in model triblock Janus spheres to self-assemble the 2D kagome and snub square lattices and the 3D pyrochlore lattice, and demonstrate self-assembly of all three target structures with the designed models. The particles designed for the kagome and snub square lattices assemble into high quality clusters of their target structures, while competition from similar polymorphs lower the yield of the pyrochlore assemblies. We find that the alchemically designed potentials do not always match physical intuition, illustrating the ability of the method to find nontrivial solutions to the optimization problem. We identify a window of second virial coefficients that result in self-assembly of the target structures, analogous to the crystallization slot in protein crystallization. 

The 2022 Tonga eruption produced ground motions dominated by force interactions between the solid Earth and atmosphere. 

Abstract On 18 November 2022, a large earthquake struck offshore southern Sumatra, generating a tsunami with 25 cm peak amplitude recorded at tide gauge station SBLT. OurW‐phase solution indicates a shallow dip of 6.2°, compatible with long‐period surface wave radiation patterns. Inversion of teleseismic body waves indicates a shallow slip distribution extending from about 10 km deep to near the trench with maximum slip of ∼4.1 m and seismic moment of  Nm (M_W7.3). Joint modeling of seismic and tsunami data indicates a shallow rigidity of ∼23 GPa. We find a low moment‐scaled radiated energy of , similar to that of the 2010M_W7.8 Mentawai event () and other tsunami earthquakes. These characteristics indicate that the 2022 event should be designated as a smaller moment magnitude tsunami earthquake compared to the other 12 well‐documented global occurrences since 1896. The 2022 event ruptured up‐dip of the 2007M_W8.4 Bengkulu earthquake, demonstrating shallow seismogenic capability of a megathrust that had experienced both a deeper seismic event and adjacent shallow aseismic afterslip. We consider seismogenic behavior of shallow megathrusts and concern for future tsunami earthquakes in subduction zones globally, noting a correlation between tsunami earthquake occurrence and subducting seafloor covered with siliceous pelagic sediments. We suggest that the combination of pelagic clay and siliceous sediments and rough seafloor topography near the trench play important roles in controlling the genesis of tsunami earthquakes along Sumatra and other regions, rather than the subduction tectonic framework of accretionary or erosive margin. 

Abstract We draw from ecological systems and social psychological theories to elucidate macrosystem‐ and microsystem‐level variables that promote and maintain gender inequities in science, technology, engineering, and math (STEM). Because gender‐STEM stereotypes undermine girls’ (and women's), but boosts boys’ (and men's), STEM interest and success, we review how they operate in STEM learning environments to differentially socialize girls and boys and undermine gender integroup relations. We propose seven practice recommendations to improve STEM K‐12 education: (1) design relational classrooms, (2) teach the history of gender inequality and bias, (3) foster collaborative and cooperative classrooms, (4) promote active learning and growth mindset strategies, (5) reframing STEM as inclusive, (6) create near‐peer mentorship programs, and (7) re‐imagine evaluation metrics. To support these practice recommendations, three policy recommendations are posited: (1) increase teacher autonomy, training, and representation, (2) re‐evaluate standardized testing, and (3) reallocate and increase government funding for public schools. 

Increasing academic participation among students from ethnic-racial underrepresented groups in STEM yields societal benefits including ameliorating economic ramifications of the labor shortages in STEM, improving scientific innovation, and providing opportunity, access, and participation in high-status STEM fields. Two longitudinal studies with students from underrepresented groups investigated the role of active learning interventions in the development of STEM self-efficacy and intentions to pursue STEM in the future. Study 1 longitudinally tracked high school students participating in a 4-week geoscience program that applied active learning techniques ranging from hands on experiments to peer discussion. High school student participants displayed increases in self-efficacy and STEM intentions from the start to completion of the program, an effect that was observed exclusively among those who reported strong program quality. Study 2 examined the role of mentorship effectiveness with a sample of community college STEM students interested in transferring to a 4-year college. Students’ relatively strong self-efficacy and STEM intentions at the start of the semester remained stable through the end of the semester. Altogether, the present research highlights the role of positive, inclusive educational climates in promoting STEM success among students from underrepresented group members. 

Climate change is increasingly predisposing polar regions to large landslides. Tsunamigenic landslides have occurred recently in Greenland (Kalaallit Nunaat), but none have been reported from the eastern fjords. In September 2023, we detected the start of a 9-day-long, global 10.88-millihertz (92-second) monochromatic very-long-period (VLP) seismic signal, originating from East Greenland. In this study, we demonstrate how this event started with a glacial thinning–induced rock-ice avalanche of 25 × 10⁶cubic meters plunging into Dickson Fjord, triggering a 200-meter-high tsunami. Simulations show that the tsunami stabilized into a 7-meter-high long-duration seiche with a frequency (11.45 millihertz) and slow amplitude decay that were nearly identical to the seismic signal. An oscillating, fjord-transverse single force with a maximum amplitude of 5 × 10¹¹newtons reproduced the seismic amplitudes and their radiation pattern relative to the fjord, demonstrating how a seiche directly caused the 9-day-long seismic signal. Our findings highlight how climate change is causing cascading, hazardous feedbacks between the cryosphere, hydrosphere, and lithosphere.