Search for: All records

Abstract Several actin-binding proteins form phase-separated condensates that promote actin filament assembly and bundling. However, the mechanism by which crosslinker multivalency, actin growth, and condensate mechanics regulate actin organization and droplet shape is not well understood. Here, using a combination of agent-based simulations and experiments, we show that a dynamically deformable droplet interface enables the emergence of tightly-bundled actin rings and weakly-bundled actin discs. We find that crosslinked bundle thickness and droplet diameter follow a power law, consistent with measurements in condensates formed by vasodilator-stimulated phosphoprotein. In addition, the dynamics of droplet deformation exhibit a dynamic snapping behavior that depends on droplet surface tension and crosslinker binding kinetics. We assess the generalizability of these predictions in condensates formed by lamellipodin and RGG. Together, these results indicate that mechanochemical feedback between droplet interfacial mechanics and crosslinker multivalency tunes actin organization and controls the dynamics of droplet deformation driven by actin networks. 

The SAGE Suite–SAGE1, SAGE2, and SAGE3–translates advances in visualization, cyberinfrastructure, and human-computer interaction into an open, scalable platform that aligns with embodied cognition to support collaborative, spatial reasoning on large displays and personal devices. Over two decades and hundreds of deployed walls worldwide, SAGE has enabled scientists, educators, and students to juxtapose heterogeneous media, sustain shared context, and accelerate sensemaking across the research lifecycle. This paper contributes: (1) a synthesis of the Suite’s translational impact across domains–from biology and atmospheric science to disaster management, health care, public outreach and workforce development; (2) a comparative framing of SAGE3 (the Smart Amplified Group Environment) among Computer Supported Cooperative Work and infinite-canvas tools; (3) the design rationale and user experience foundations of SAGE3’s “spatial thinking operating system,” including boards, rooms, wall viewports, and multi-user attention/flow mechanisms; (4) a modular architecture that delivers low-latency synchronization, extensibility via plugins, and privacy-aware deployment; and (5) a paradigm for human–Artificial Intelligence (AI) collaboration that spatializes notebooks and conversational workflows, enabling multi-user, multi-AI interaction grounded in shared visual context. We also surface systemic challenges in recognizing software-as-instrument within academic incentives and document emergent usage patterns spanning synchronous/asynchronous, co-located/distributed work. SAGE3 demonstrates how open, research-driven cyberinfrastructure can couple spatial cognition with collective intelligence to advance scientific collaboration and decision-making. 

Recent advances in Natural Language Interfaces (NLIs) and Large Language Models (LLMs) have transformed the way we tackle NLP tasks, shifting the focus towards a more Pragmatics-based perspective. This shift enables more natural interactions between humans and voice assistants, which have historically been difficult to achieve. Pragmatics involves understanding how users often speak out of turn, interrupt one another, or provide relevant information without being explicitly asked (maxim of quantity). To explore this, we developed a digital assistant that continuously listens to conversations and proactively generates relevant visualizations during data exploration tasks. In a within-subject study, participants interacted with both proactive and non-proactive versions of a voice assistant while exploring the Hawaii Climate Data Portal (HCDP). Results suggest that interaction with the proactive assistant increased the total number of utterances and discoveries, facilitated quicker and more reliable insights, and led to greater usage of the system’s chart capabilities. Our study highlights the potential of proactive AI in NLIs and identifies key challenges in its implementation, offering insights for future research. 

Abstract. Bromine monoxide (BrO) is relevant to atmospheric oxidative capacity, affecting the lifetime of greenhouse gases (i.e., methane, dimethylsulfide) and mercury oxidation. However, measurements of BrO radical vertical profiles are rare, and BrO is highly variable. As a result, the few available aircraft observations in different regions of the atmosphere are not easily reconciled. Autonomous multi-axis differential optical absorption spectroscopy (MAX-DOAS) instruments placed at remote mountaintop observatories (MT-DOAS) present a cost-effective alternative to aircraft, with the potential to probe the climate-relevant yet understudied free troposphere more routinely. Here, we describe an innovative full-atmosphere BrO and formaldehyde (HCHO) profile retrieval algorithm using MT-DOAS measurements at Mauna Loa Observatory (MLO – 19.536° N, 155.577° W; 3401 m a.s.l.). The retrieval is based on time-dependent optimal estimation and simultaneously inverts 190+ individual BrO (and formaldehyde, HCHO) SCDs (slant column densities; SCD = dSCD + SCDRef) from solar stray light spectra measured in the zenith and off-axis geometries at high and low solar zenith angles (92° > SZA > 30°) to derive BrO concentration profiles from 1.9 to 35 km with 7.5 degrees of freedom (DoFs). Two case study days are characterized by the absence (26 April 2017, base case) and presence of a Rossby-wave-breaking double tropopause (29 April 2017, RW-DT case). Stratospheric-BrO vertical columns are nearly identical on both days (VCD = (1.5 ± 0.2) × 1013 molec. cm−2), and the stratospheric-BrO profile peaks at a lower altitude during the RW-DT (1.6–2.0 DoFs). Tropospheric-BrO VCDs increase from (0.70 ± 0.14) × 1013 molec. cm−2 (base case) to (1.00 ± 0.14) × 1013 molec. cm−2 (RW-DT) owing to a 3-fold increase in BrO in the upper troposphere (1.7–1.9 DoFs). BrO at MLO increases from (0.23 ± 0.03) pptv (base case) to (0.46 ± 0.03) pptv (RW-DT) and is characterized by an added time resolution (∼ 3.8 DoFs). Up to (0.9 ± 0.1) pptv BrO is observed above MLO in the lower free troposphere in the absence of the double tropopause. We validate the retrieval using aircraft BrO profiles and in situ HCHO measurements aboard the NSF/NCAR GV aircraft above MLO (11 January 2014) that establish BrO peaks around 2.4 pptv above 13 km in the upper troposphere–lower stratosphere (UTLS) during a similar RW-DT event (0.83 × 1013 molec. cm2 tropospheric-BrO VCD above 2 km). The tropospheric-BrO profile measured using MT-DOAS (RW-DT case) and using the aircraft agree well (after averaging-kernel smoothing). Furthermore, these tropospheric-BrO profiles over the central Pacific Ocean are found to closely resemble those over the eastern Pacific Ocean (2–14 km) and are in contrast to those over the western Pacific Ocean, where a C-shaped tropospheric-BrO profile shape has been observed. 

With the emergence of Artificial Intelligence, it’s becoming essential for everyone—not just scientists and students—to harness its potential to stay competitive, think more critically, and drive innovation in a rapidly evolving world. SAGE3 is an open-source platform designed to help individuals and teams collaborate effectively—with each other and with AI—to accelerate the process of understanding, problem-solving, and discovery. It empowers everyday citizens to become smarter and more innovative by making complex information more accessible and actionable. Developed from over 20 years of National Science Foundation–funded research, SAGE3 is grounded in a deep understanding of how people work together across disciplines and interact with diverse streams of data. SAGE3 supports translational and convergent research, making it ideal for integrating insights from science, technology, community knowledge, and policy to tackle real-world challenges. It enables people to work with large and varied information sources—collaborating seamlessly with AI to reach decisions more quickly, clearly, and confidently. Whether working side-by-side on expansive shared display walls or contributing remotely from a laptop—at home, at work, or while traveling—SAGE3 enables flexible, co-located and distributed collaboration. It transforms static data into shared understanding, powering more informed, creative, and collective decision-making for all. 

Background: Glyoxal has been implicated as a significant contributor to the formation of secondary organic aerosols, which play a key role in our ability to estimate the impact of aerosols on climate. Elevated concentrations of glyoxal over remote ocean waters suggests that there is an additional source, distinct from urban and forest environments, which has yet to be identified. Herein, we demonstrate that the ocean can serve as an appreciable source of glyoxal in the atmosphere due to microbiological activity. Methods and Results: Based on mass spectrometric analyses of nascent sea spray aerosols and the sea surface microlayer (SSML) of naturally occurring algal blooms, we provide evidence that during the algae death phase phospholipids become enriched in the SSML and undergo autoxidation thereby generating glyoxal as a degradation product. Conclusions: We propose that the death phase of an algal bloom could serve as an important and currently missing source of glyoxal in the atmosphere. 

Abstract. Carbonyl sulfide (COS) is the most abundant sulfur gas in the atmosphere with links to terrestrial and oceanic productivity. We measured COS in ice core air from an intermediate-depth ice core from the South Pole using both dry and wet extraction methods, recovering a 52 500-year record. We find evidence for COS production in the firn, altering the atmospheric signal preserved in the ice core. Mean sea salt aerosol concentrations from the same depth are a good proxy for the COS production, which disproportionately impacts the measurements from glacial period ice with high sea salt aerosol concentrations. The COS measurements are corrected using sea salt sodium (ssNa) as a proxy for the excess COS resulting from the production. The ssNa-corrected COS record displays substantially less COS in the glacial period atmosphere than the Holocene and a 2 to 4-fold COS rise during the deglaciation synchronous with the associated climate signal. The deglacial COS rise was primarily source driven. Oceanic emissions in the form of COS, carbon disulfide (CS2), and dimethylsulfide (DMS) are collectively the largest natural source of atmospheric COS. A large increase in ocean COS emissions during the deglaciation suggests enhancements in emissions of ocean sulfur gases via processes that involve ocean productivity, although we cannot quantify individual contributions from each gas.