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1. Small Mammal Exclosure Study (SMES) Ant Data from Chihuahuan Desert Grassland and Shrubland at the Sevilleta National Wildlife Refuge, New Mexico (1995-2005)

   https://doi.org/10.6073/pasta/c4963aa3363d18ac99bd40307db2249d  

   Lightfoot, David (January 2016, Environmental Data Initiative)

   Animal consumers have important roles in ecosystems, determining plant species composition and structure, regulating rates of plant production and nutrients, and altering soil structure and chemistry. This is data for numbers and species of seed harvester ant nests mapped from each of the SMES study plots. Seed harvester ant nests were mapped on each of the study plots once each year in the autumn. Ant nest maps were drawn on to pre-designed plot diagrams. Each nest was located on the diagram in reference to one of the 36 vegetation quadrat marker posts. The distance from the post, direction from the post, and species name were plotted on the map diagram. Data such as total numbers of nests of each ant species, and spatial arrangement of nests, were then taken from the diagram maps. The following question was asked: Do small mammals interact with other herbivore and granivore consumers enough to affect the species composition and abundances of other consumers such as ants? 

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2. Legumes regulate grassland soil N cycling and its response to variation in species diversity and N supply but not CO ₂

   https://doi.org/10.1111/gcb.14636  

   Wei, Xiaorong; Reich, Peter_B; Hobbie, Sarah_E (April 2019, Global Change Biology)

   Abstract Legumes are an important component of plant diversity that modulate nitrogen (N) cycling in many terrestrial ecosystems. Limited knowledge of legume effects on soil N cycling and its response to global change factors and plant diversity hinders a general understanding of whether and how legumes broadly regulate the response of soil N availability to those factors. In a 17‐year study of perennial grassland species grown under ambient and elevated (+180 ppm) CO₂and ambient and enriched (+4 g N m⁻² year⁻¹) N environments, we compared pure legume plots with plots dominated by or including other herbaceous functional groups (and containing one or four species) to assess the effect of legumes on N cycling (net N mineralization rate and inorganic N pools). We also examined the effects of numbers of legume species (from zero to four) in four‐species mixed plots on soil N cycling. We hypothesized that legumes would increase N mineralization rates most in those treatments with the greatest diversity and the greatest relative limitation by and competition for N. Results partially supported these hypotheses. Plots with greater dominance by legumes had greater soil nitrate concentrations and mineralization rates. Higher species richness significantly increased the impact of legumes on soil N metrics, with 349% and 505% higher mineralization rates and nitrate concentrations in four‐species plots containing legumes compared to legume‐free four‐species plots, in contrast to 185% and 129% greater values, respectively, in pure legume than nonlegume monoculture plots. N‐fertilized plots had greater legume effects on soil nitrate, but lower legume effects on net N mineralization. In contrast, neither elevated CO₂nor its interaction with legumes affected net N mineralization. These results indicate that legumes markedly influence the response of soil N cycling to some, but not all, global change drivers. 

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3. Fractal contours: Order, chaos, and art

   https://doi.org/10.1063/5.0207823  

   McDonough, John; Herczyński, Andrzej (June 2024, Chaos: An Interdisciplinary Journal of Nonlinear Science)

   Over the recent decades, a variety of indices, such as the fractal dimension, Hurst exponent, or Betti numbers, have been used to characterize structural or topological properties of art via a singular parameter, which could then help to classify artworks. A single fractal dimension, in particular, has been commonly interpreted as characteristic of the entire image, such as an abstract painting, whether binary, gray-scale, or in color, and whether self-similar or not. There is now ample evidence, however, that fractal exponents obtained using the standard box-counting are strongly dependent on the details of the method adopted, and on fitting straight lines to the entire scaling plots, which are typically nonlinear. Here, we propose a more discriminating approach with the aim of obtaining robust scaling plots and extracting relevant information encoded in them without any fitting routines. To this goal, we carefully average over all possible grid locations at each scale, rendering scaling plots independent of any particular choice of grids and, crucially, of the orientation of images. We then calculate the derivatives of the scaling plots, so that an image is described by a continuous function, its fractal contour, rather than a single scaling exponent valid over a limited range of scales. We test this method on synthetic examples, ordered and random, then on images of algorithmically defined fractals, and finally, examine selected abstract paintings and prints by acknowledged masters of modern art. 

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4. Visualizing the Hydrogen Atomic Orbitals: A Tool for Undergraduate Physical Chemistry

   https://doi.org/10.1021/acs.jchemed.4c00547  

   Hanson, Matthew D (August 2024, Journal of Chemical Education)

   Despite the prominence of orbitals throughout the undergraduate chemistry curriculum, high-quality visualization of atomic orbitals is out of reach for most scientists. Rigorously visualizing the atomic orbitals even for simple hydrogen-like atoms and ions is rather challenging due to the complex 3-D structure and geometric variability of the orbitals across three distinct quantum numbers. In this work, a graphical user interface (GUI)-based tool for visualizing 3-D volumetric density plots of hydrogen atomic orbitals is introduced. This tool is written in Python, and a Jupyter notebook version with explanatory blocks interspersed in the code is included for pedagogical purposes. The user can manipulate a large number of features using the GUI, which allows customization of the orbital illustrations. Because this visualizer is capable of visualizing orbitals with any quantum numbers and showing their nodal surfaces, it can serve as a supplement to students’ lecture and textbook education on this topic. 

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5. Long-term trends in abundance of Lepidoptera larvae at Hubbard Brook Experimental Forest and three additional northern hardwood forest sites, 1986-2021

   https://doi.org/10.6073/pasta/30607ce5b4d7d4b5d19d24b13bd711d8  

   Zammarelli, Miranda B; Kaiser, Sara A; Ayres, Matthew P; Holmes, Richard T; Rodenhouse, Nicholas L (January 2022, Environmental Data Initiative)

   Numbers and lengths of Lepidoptera larvae (caterpillars, all species) were censused on shrub level foliage at biweekly intervals from late May/early June through late July/early August each year. Measurements were conducted on the Main bird plot in the Hubbard Brook Experimental Forest and on three additional plots within the White Mountain National Forest from 1986-1997. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

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