Search for: All records

The TTG2 transcription factor ofArabidopsisregulates a set of epidermal traits, including the differentiation of leaf trichomes, flavonoid pigment production in cells of the inner testa (or seed coat) layer and mucilage production in specialized cells of the outer testa layer. Despite the fact that TTG2 has been known for over twenty years as an important regulator of multiple developmental pathways, little has been discovered about the downstream mechanisms by which TTG2 co-regulates these epidermal features. In this study, we present evidence of phosphoinositide lipid signaling as a mechanism for the regulation of TTG2-dependent epidermal pathways. Overexpression of theAtPLC1gene rescues the trichome and seed coat phenotypes of thettg2-1mutant plant. Moreover, in the case of seed coat color rescue,AtPLC1overexpression restored expression of the TTG2 flavonoid pathway target genes,TT12andTT13/AHA10. Consistent with these observations, a dominantAtPLC1T-DNA insertion allele (plc1-1D)promotes trichome development in both wild-type andttg2-3plants. Also,AtPLC1promoter:GUS analysis shows expression in trichomes and this expression appears dependent on TTG2. Taken together, the discovery of a genetic interaction betweenTTG2andAtPLC1suggests a role for phosphoinositide signaling in the regulation of trichome development, flavonoid pigment biosynthesis and the differentiation of mucilage-producing cells of the seed coat. This finding provides new avenues for future research at the intersection of the TTG2-dependent developmental pathways and the numerous molecular and cellular phenomena influenced by phospholipid signaling.

 

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. 

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. 

Over the past three decades, research efforts and interventions have been implemented across the United States to increase the persistent underrepresentation of minority (URM) students in science, technology, engineering, and math (STEM). This Element systematically compares STEM interventions that offer resources and opportunities related to mentorship, research, and more. We organize the findings of this literature into a multiphase framework of STEM integration and identity development. We propose four distinct phases of STEM integration: Phase 1: High School; Phase 2: Pre-College Summer; Phase 3: College First Year; and Phase 4: College Second Year through Graduation. We combine tenets of theories about social identity, stereotypes and bias, and the five-factor operationalization of identity formation to describe each phase of STEM integration. Findings indicate the importance of exploration through exposure to STEM material, mentorship, and diverse STEM communities. We generalize lessons from STEM interventions to URM students across institutions. 

On 22 December 2018, a devastating tsunami struck Sunda Strait, Indonesia without warning, leaving 437 dead and thousands injured along the western Java and southern Sumatra coastlines. Synthetic aperture radar and broadband seismic observations demonstrate that a small, <~0.2 km 3 landslide on the southwestern flank of the actively erupting volcano Anak Krakatau generated the tsunami. The landslide did not produce strong short-period seismic waves; thus, precursory ground shaking did not provide a tsunami warning. The source of long-period ground motions during the landslide can be represented as a 12° upward-dipping single-force directed northeastward, with peak magnitude of ~6.1 × 10 11 N and quasi-sinusoidal time duration of ~70 s. Rapid quantification of a landslide source process by long-period seismic wave inversions for moment-tensor and single-force parameterizations using regional seismic data available within ~8 min can provide a basis for future fast tsunami warnings, as is also the case for tsunami earthquakes. 

SUMMARY We recently found the original Omori seismograms recorded at Hongo, Tokyo, of the 1922 Atacama, Chile, earthquake (MS = 8.3) in the historical seismogram archive of the Earthquake Research Institute (ERI) of the University of Tokyo. These recordings enable a quantitative investigation of long-period seismic radiation from the 1922 earthquake. We document and provide interpretation of these seismograms together with a few other seismograms from Mizusawa, Japan, Uppsala, Sweden, Strasbourg, France, Zi-ka-wei, China and De Bilt, Netherlands. The 1922 event is of significant historical interest concerning the cause of tsunami, discovery of G wave, and study of various seismic phase and first-motion data. Also, because of its spatial proximity to the 1943, 1995 and 2015 great earthquakes in Chile, the 1922 event provides useful information on similarity and variability of great earthquakes on a subduction-zone boundary. The 1922 source region, having previously ruptured in 1796 and 1819, is considered to have significant seismic hazard. The focus of this paper is to document the 1922 seismograms so that they can be used for further seismological studies on global subduction zones. Since the instrument constants of the Omori seismographs were only incompletely documented, we estimate them using the waveforms of the observed records, a calibration pulse recorded on the seismogram and the waveforms of better calibrated Uppsala Wiechert seismograms. Comparison of the Hongo Omori seismograms with those of the 1995 Antofagasta, Chile, earthquake (Mw = 8.0) and the 2015 Illapel, Chile, earthquake (Mw = 8.3) suggests that the 1922 event is similar to the 1995 and 2015 events in mechanism (i.e. on the plate boundary megathrust) and rupture characteristics (i.e. not a tsunami earthquake) with Mw = 8.6 ± 0.25. However, the initial fine scale rupture process varies significantly from event to event. The G1 and G2, and R1 and R2 of the 1922 event are comparable in amplitude, suggesting a bilateral rupture, which is uncommon for large megathrust earthquakes.