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Metabolic biochemical models of N fixation for sulfide oxidizers, methanogens, and methanotrophs
No full textDinitrogen (N) fixation provides bioavailable nitrogen to the biosphere. However, in some habitats (e.g., sediments), the metabolic pathways of organisms carrying out N fixation are unclear. We present metabolic models representing various chemotrophic N fixers, which simulate potential pathways of electron transport and energy flow, resulting in predictions of whole-cell stoichiometries. By balancing mass, electrons, and energy for metabolic half-reactions, we quantify the electron usage for nine N fixers. Our results demonstrate that all modeled organisms fix sufficient N for growth. Aerobic organisms allocate more electrons to N fixation and growth, yielding more biomass and fixing more N, while methanogens using acetate and organisms using sulfate allocate fewer electrons. This work can be applied to investigate the depth distribution of N fixers based on nutrient availability, complementing field measurements of biogeochemical processes and microbial communities.IMPORTANCEN fixation is an important process in the global N cycle. Researchers have developed models for heterotrophic and photoautotrophic N fixers, but there is a lack of modeling studies on chemoautotrophic N fixers. Here, we built nine biochemical models for different chemoautotrophic N fixers by combining different types of half-chemical reactions. We include three sulfide oxidizers using different electron acceptors (O, NO, and Fe), contributing to the sulfur, nitrogen, and iron cycles in the sediment. We have two methanogens using different substrates (H and acetate) and four methanotrophs using different electron acceptors (O, NO, Fe, and SO). By modeling these methane producers and users in the sediment and their N-fixing metabolic pathways, our work can provide insight for future carbon cycle studies. This study outlines various metabolic pathways that can facilitate N fixation, with implications for where in the environment they might occur
Heuristic Approaches for Coordinating Collaborative Heterogeneous Robotic Systems in Harvesting Automation with Size Constraints
No full textMulti-agent coordination with task allocation, routing, and scheduling presents critical challenges when deploying heterogeneous robotic systems in constrained agricultural environments. These systems involve real-time sensing during their operations with various sensors, and having quick updates on coordination based on sensed data is critical. This paper addresses the specific requirements of harvesting automation through three heuristic approaches: (1) primal-dual workload balancing inspired by combinatorial optimization techniques, (2) greedy task assignment with iterative local optimization, and (3) LLM-based constraint processing through prompt engineering. Our agricultural application scenario incorporates robot size constraints for navigating narrow crop rows while optimizing task completion time. The greedy heuristic employs rapid initial task allocation based on proximity and capability matching, followed by iterative route refinement. The primal-dual approach adapts combinatorial optimization principles from recent multi-depot routing solutions, dynamically redistributing workloads between robots through dual variable adjustments to minimize maximum completion time. The LLM-based method utilizes structured prompt engineering to encode spatial constraints and robot capabilities, generating feasible solutions through successive refinement cycles. We implemented and compared these approaches through extensive simulations. Preliminary results demonstrate that all three approaches produce feasible solutions with reasonable quality. The results demonstrate the potential of the methods for real-world applications that can be quickly adopted into variations of the problem to offer valuable insights into solving complex coordination problems with heterogeneous multi-robot systems
Critical Review on Recycling of Erdite/KFeS2 Rods from Waste Sludge as Environmental Functional Materials
No full textThe ternary compounds such as erdite (NaFeS2‧2H2O) and potassium thioferrite (KFeS2) are attracting some interests from scientific communities due to their potential applicability in environmental protection. Such compounds were synthesized by using chemical-pure reagents and/or waste Fe-rich sludge, via alkaline hydrothermal route, and also developed from lab- to pilot-scale at the relative low temperature of 80 °C under atmosphere condition. In this paper, the hydrothermal synthesis of two crystals was reviewed, in consideration of the parameters, e.g., OH−/HS− dosage, impurities, temperature, and Na+/K+. According, a newly process was explained for the radial growth of (FeS2)nn− chain and cleavage as rods. The spontaneous hydrolysis and/or decomposition of erdite and/or KFeS2 crystal in water solution was also discussed, along with their potential application in environmental pollution control
THE ANISOTROPIC INTERIOR TRANSMISSION EIGENVALUE PROBLEM WITH A CONDUCTIVE BOUNDARY
No full textIn this paper, we study the transmission eigenvalue problem for an anisotropic material with a conductive boundary. We prove that the transmission eigenvalues for this problem exist and are, at most, a discrete set. We also study the dependence of the transmission eigenvalues on the physical parameters and prove that the first transmission eigenvalue is monotonic. We then consider the limiting behavior of the transmission eigenvalues as the conductive boundary parameter η vanishes or goes to infinity in magnitude. Finally, we provide numerical examples on three domains to demonstrate our theoretical results
Eponyms, Heirlooms, Living Memory, and the Planty Memorialization of People
No full textWhile memorialization often invokes stony landscapes of public art, named buildings, and engraved plaques, living memorials occupy parallel and intersecting memory contexts. Plants ascribe processes of memorialization into their landscapes and broader meanings. This paper explores one subsection of these planty memorializations by highlighting fruits, vegetables, and grains whose names include eponyms, or names derived from other people’s names. We also unpack eponyms themselves and their gendered, politicized, and racialized legacies and the potential for both eponyms and their associated living memorials to perpetuate violence. We connect living memorials, eponyms, and their stone-based or toponymic counterparts to patterns within memorial landscapes and the work of memorial reckoning. While we find many representational similarities across memorial patterns, key differences emerge in how certain living memorials have been and continue to be challenged and changed, particularly in comparison to broader patterns of biologically-rooted eponyms and the memorial reckoning of our toponymic landscapes
Transforming Insights Into Action: My ILC 2025 Experience [Women in Engineering]
No full textThe IEEE Women in Engineering International Leadership Conference (ILC) 2025 was held in San Jose, California, in May 2025. Volunteers from the Power Electronics Society (PELS) Women in Engineering (WIE) Committee had the honor of attending and actively participating in this inspiring event. In this article, the authors reflect on their experiences at ILC 2025, highlighting key takeaways, personal growth, and strategies for implementing change within their local communities. This year, the IEEE Power Electronics Society proudly sponsored the conference and supported one of the invited session speakers through its newly established travel grant program. The recipient, also one of the authors of this article, Prof. Prerna Gaur from the NSUT Delhi (West Campus), contributed to the event with a powerful session on leadership and empowerment. The article also features highlights from the keynote addresses, along with reflections from the PELS WIE volunteers on recent initiatives within their local chapters
Probabilistic Galaxy Field Generation with Diffusion Models
No full textIn the era of precision cosmology, the ability to generate accurate and large-scale galaxy catalogs is crucial for advancing our understanding of the universe. With the flood of cosmological data from current and upcoming missions, generating theoretical predictions to compare with these observations is essential for constraining key cosmological parameters. While traditional methods, such as the Halo-Occupation Distribution (HOD), have provided foundational insights, they struggle to balance the need for both accuracy and computational efficiency. High-fidelity hydrodynamic simulations offer improved precision but are computationally expensive and resource-intensive. In this work, we introduce a novel machine learning approach that harnesses Convolutional Neural Networks (CNNs) and Diffusion Models, trained on the CAMELS simulation suite, to bridge the gap between computationally inexpensive dark matter simulations and the galaxy distributions of more costly hydrodynamic simulations. Our method not only outperforms traditional HOD techniques in accuracy but also significantly accelerates the simulation process, offering a scalable solution for next-generation cosmological surveys. This advancement has the potential to revolutionize galaxy catalog generation, enabling more precise, data-driven cosmological analyses
Tundra recovery post-fire in the Yukon-Kuskokwim Delta, Alaska
Get PDFThe extent of wildfires in tundra ecosystems has dramatically increased since the turn of the 21st century due to climate change and the resulting amplified Arctic warming. We simultaneously studied the recovery of vegetation, subsurface soil moisture, and active layer thickness (ALT) post-fire in the permafrost-underlain uplands of the Yukon-Kuskokwim Delta in southwestern Alaska to understand the interaction between these factors and their potential implications. We used a space-for-time substitution methodology with 2017 Landsat 8 imagery and synthetic aperture radar products, along with 2016 field data, to analyze tundra recovery trajectories in areas burned from 1953 to 2017. We found that spectral indices describing vegetation greenness and surface albedo in burned areas approached the unburned baseline within a decade post-fire, but ecological succession takes decades. ALT was higher in burned areas compared to unburned areas initially after the fire but negatively correlated with soil moisture. Soil moisture was significantly higher in burned areas than in unburned areas. Water table depth (WTD) was 10 cm shallower in burned areas, consistent with 10 cm of the surface organic layer burned off during fire. Soil moisture and WTD did not recover in the 46 years covered by this study and appear linked to the long recovery time of the organic layer
Aortic Arch Morphology Is Associated With Long-term Mortality After Transcatheter Aortic Valve Replacement
No full textIn this focused analysis, we hypothesized that an angulated aortic arch phenotype (type III) is associated with increased post-TAVR mortality. We identified patients who underwent TAVR at Mayo Clinic (Rochester, Minnesota) between February 2012 and July 2022 and had a pre-TAVR computed tomography angiography scan with adequate aortic arch visualization. Two independent reviewers (G.L. and H.A.) conducted a manual review to classify aortic arch types and to assess clinical outcomes
Review of Nanomaterials in Pavement Engineering
No full textAs one of the most widely used pavement materials worldwide, asphalt is renowned for its exceptional waterproofing, adhesion, durability, and bonding properties. However, the rapid growth in traffic loads and driving speeds in recent years has significantly shortened the service life of asphalt pavements, leading to increased maintenance demands and heightened accident risks due to deteriorated pavement conditions. These challenges underscore the urgent need to enhance the asphalt pavement performance to meet the evolving demands of modern transportation. The advent of nanomaterials, with their unique size-dependent properties and surface effects, presents promising opportunities for improving the performance of asphalt mixtures. This paper provides a comprehensive review of various nanomaterials with potential applications in asphalt modification, focusing on their material characteristics, mechanisms of action, and evaluation methods. The findings demonstrate that incorporating nanoparticles can markedly enhance asphalt’s properties, including its viscosity, stiffness, elasticity, fatigue resistance, aging resistance, and ultraviolet radiation resistance, thereby improving pavement quality and prolonging service life. While challenges remain, including high costs, limited scalability, and environmental concerns, a life cycle analysis suggests that the long-term economic benefits of nanomaterials, such as reduced maintenance costs and extended pavement lifespan, make them a viable solution for road engineering. Future research should prioritize the development of effective dispersion techniques, the mitigation of environmental impacts, and the assessment of long-term performance to facilitate the sustainable and large-scale application of nanomaterials in road infrastructure