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1. Taraxerol abundance as a proxy for in situ mangrove sediment

   https://doi.org/10.1016/j.orggeochem.2024.104767  

   Sefton, Juliet P; Kemp, Andrew C; Vane, Christopher H; Kim, Alexander W; Bernhardt, Christopher E; Johnson, Jonathan; Engelhart, Simon E (May 2024, Organic Geochemistry)
2. A Tangible Spherical Proxy for Object Manipulation in Augmented Reality

   https://doi.org/10.1109/VR46266.2020.00-63  

   Englmeier, David; Dorner, Julia; Butz, Andreas; Hollerer, Tobias (March 2020, IEEE Conference on Virtual Reality and 3D User Interfaces (VR), 2020)

   In this paper, we explore how a familiarly shaped object can serve as a physical proxy to manipulate virtual objects in Augmented Reality (AR) environments. Using the example of a tangible, handheld sphere, we demonstrate how irregularly shaped virtual objects can be selected, transformed, and released. After a brief description of the implementation of the tangible proxy, we present a buttonless interaction technique suited to the characteristics of the sphere. In a user study (N = 30), we compare our approach with three different controller-based methods that increasingly rely on physical buttons. As a use case, we focused on an alignment task that had to be completed in mid-air as well as on a flat surface. Results show that our concept has advantages over two of the controller-based methods regarding task completion time and user ratings. Our findings inform research on integrating tangible interaction into AR experiences. 

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3. Isotopic clumping in wood as a proxy for photorespiration in trees

   https://doi.org/10.1073/pnas.2306736120  

   Lloyd, Max K.; Stein, Rebekah A.; Ibarra, Daniel E.; Barclay, Richard S.; Wing, Scott L.; Stahle, David W.; Dawson, Todd E.; Stolper, Daniel A. (November 2023, Proceedings of the National Academy of Sciences)

   Photorespiration can limit gross primary productivity in terrestrial plants. The rate of photorespiration relative to carbon fixation increases with temperature and decreases with atmospheric [CO₂]. However, the extent to which this rate varies in the environment is unclear. Here, we introduce a proxy for relative photorespiration rate based on the clumped isotopic composition of methoxyl groups (R–O–CH₃) in wood. Most methoxyl C–H bonds are formed either during photorespiration or the Calvin cycle and thus their isotopic composition may be sensitive to the mixing ratio of these pathways. In water-replete growing conditions, we find that the abundance of the clumped isotopologue¹³CH₂D correlates with temperature (18–28 °C) and atmospheric [CO₂] (280–1000 ppm), consistent with a common dependence on relative photorespiration rate. When applied to a global dataset of wood, we observe global trends of isotopic clumping with climate and water availability. Clumped isotopic compositions are similar across environments with temperatures below ~18 °C. Above ~18 °C, clumped isotopic compositions in water-limited and water-replete trees increasingly diverge. We propose that trees from hotter climates photorespire substantially more than trees from cooler climates. How increased photorespiration is managed depends on water availability: water-replete trees export more photorespiratory metabolites to lignin whereas water-limited trees either export fewer overall or direct more to other sinks that mitigate water stress. These disparate trends indicate contrasting responses of photorespiration rate (and thus gross primary productivity) to a future high-[CO₂] world. This work enables reconstructing photorespiration rates in the geologic past using fossil wood. 

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4. Neuronal Variability as a Proxy for Network State

   https://doi.org/10.1016/j.tins.2018.02.003  

   Nogueira, Ramon; Lawrie, Sofía; Moreno-Bote, Rubén (April 2018, Trends in Neurosciences)
5. Mud in sandy riverbed deposits as a proxy for ancientfine-sediment supply

   https://doi.org/10.1130/G48251.1  

   Wysocki, N.; Hajek, E. (April 2021, Geology)

   null (Ed.)

   The amount of silt and clay available to rivers reflects source-terrain composition and weathering and can be a primary control on the form and dynamics of channel networks. Fine sediment also affects the permeability of buried fluvial reservoirs. Despite this significance, there is currently a lack of methods for reconstructing how much fine sediment was transported by ancient rivers. Mud accumulations in sandy river deposits are often interpreted as indicators of variable flow conditions; however, these deposits may present an opportunity to constrain how much fine sediment was transported through ancient rivers. We report results from a series of experiments designed to evaluate how much clay and silt are preserved in sandy riverbed deposits under constant and variable discharge conditions. Our results demonstrate that (1) mud deposits, including drapes and lenses, form readily under constant, high-discharge conditions, (2) the amount of fine sediment recovered from bed-material deposits increases as fine-sediment supply increases, and (3) fine-sediment retention is higher during bed aggradation than during bypass conditions. These results indicate that the net retention of clay and silt in sandy riverbed deposits may be a simple but powerful proxy for comparing the overall amount of fine sediment supplied to ancient rivers. 

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