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1. Impact of stream power gradients on storage of sediment and carbon on channel margins and floodplains

   https://doi.org/10.1130/G50339.1  

   Gartner, John D.; Renshaw, Carl E.; Landis, Joshua; Magilligan, Francis J. (November 2022, Geology)

   Abstract Spatial complexity impacts the resilience of river ecosystems by mediating processes that control the sources and sinks of sediment and organic material. Using four independent geochemical tracers and three morphometric indices, we show that downstream spatial gradients in stream power (Ω) predict storage of material in the channels and margins and/or floodplains. A field test in a 48 km2 watershed demonstrates that reaches with downstream decreases in Ω coincide with wider floodplains and elevated inventories of 137Cs, 210Pbex (ex—excess), and organic matter in locations of the ~3 to 20 yr floodplain. In contrast, reaches with downstream increases in Ω coincide with narrower floodplains and decreased inventories of 137Cs, 210Pbex, and organic matter. The occurrence of in-channel bedrock exposures and the activity of short-lived 7Be in within-channel sediments also correlate with downstream Ω gradients, demonstrating a link, over both short and long time scales, between withinchannel processes and floodplain-forming processes. The combined geochemical and physical characteristics demonstrate the importance of downstream gradients in sediment transport, characterized by downstream changes in stream power rather than at-a-point stream power, in determining spatial complexity in carbon and sediment storage at intermediate scales (102 to 103 m) in river systems. 

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2. On theorems of Wirsing and Sanders

   https://doi.org/10.4064/aa180125-20-9  

   Ge, Zhenchao; Lê, Thái Hoàng (January 2019, Acta Arithmetica)
3. On the Impacts of Flow on the Migration and Growth of Cancer Cells

   https://doi.org/10.1115/dmd2022-1050  

   Akerkouch, Lahcen; Le, Trung; Jasuja, Haneesh; Katti, Kalpana; Katti, Dinesh (April 2022, Proceedings of the 2022 Design of Medical Devices Conference)

   Our study aims to identify the role of fluid flow in the growth of human bone cancer cells during metastasis. In our experiments, the cancer cells are seeded on the surface of cylindrical scaffolds in a bioreactor. The flow is laminar flow, which mimics the physiological conditions of the human body. A full-scale 3D high-resolution computational mesh of scaffold was created based on the physical scaffold's Micro-CT scans using open-source imaging software Slicer3D and Meshmixer. To investigate the influences of the flow on the seeded cells, we performed Computational Fluid Dynamics (CFD) simulations with the immersed boundary method (Gilmanov, Le, Sotiropoulos, JCP 300, 1, 2015). The computational domain was generated using the commercial software Gridgen. Our results show that the fluid flow velocity is highly dependent on the shape and pore sizes. In addition, the magnitude of the velocity on the surface where the cells are seeded is in between [0-0.05] μm/sallowing the cells to grow without being detached from the surface of the scaffold. Our future work will focus on (i) investigating the role of the shear stress on the distribution and orientation of the cancer cells. (ii) Simulating multiple scaffolds within the bioreactor to further quantify the impact of the gap on the flow velocity and shear. 

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4. On the Unique Features and Benefits of On-Demand Distribution Models

   Pazour, Jennifer A; Unnu, Kaan (January 2018, Progress in material handling research)

   To close the gap between current distribution operations and today’s customer expectations, firms need to think differently about how resources are acquired, managed and allocated to fulfill customer requests. Rather than optimize planned resource capacity acquired through ownership or long- term partnerships, this work focuses on a specific supply-side innovation – on-demand distribution platforms. On-demand distribution systems move, store, and fulfill goods by matching autonomous suppliers' resources (warehouse space, fulfillment capacity, truck space, delivery services) to requests on-demand. On-demand warehousing systems can provide resource elasticity by allowing capacity decisions to be made at a finer granularity (at the pallet-level) and commitment (monthly versus yearly), than construct or lease options. However, such systems are inherently more complex than traditional systems, as well as have varying costs and operational structures (e.g., higher variable costs, but little or no fixed costs). New decision- supporting models are needed to capture these trade-offs. 

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5. On a conjecture of Talagrand on selector processes and a consequence on positive empirical processes

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   Park, Jinyoung; Pham, Huy Tuan (May 2024, Annals of Mathematics)