Recent Submissions

  • Item
    Primate Bone Histomorphology and its Relationship to Biomechanical Forces
    (1994) Paine, Robert R.
    Observations of nonhuman primate long bone microanatomy were undertaken with the explicit goal of recording intra- and interspecific variation in the percentage of osteonal bone. One-hundred and eight specimens with age, sex, body size, and positional behavior data representing 7 species (Galago seneqalensis, Otolemur crassicaudatus, Macaca fascicularis, Macaca mulatta, Macaca arctoides, Erythrocebus patas, and Cercopithecus aethiops) were examined. Humeral and femoral shafts were examined histologically at the proximal, midshaft, and distal cross sections. Furthermore, the humeral and femoral midshaft sections were histologically examined at the anterior, posterior, medial, and lateral quadrants. Each cross section and quadrant were read specifically for percentages of osteonal bone. Data on cortical bone area and cortical thickness were also recorded for each section. Descriptive statistics, analysis of variance, and Model II regression (maximum likelihood estimation) were used to test for intra- and interspecific variation in osteonal bone for this population of primates. In general, several points concerning primate skeletal microanatomy have been revealed: 1) humeral and femoral microanatomy do not mirror each other in osteonal pattern, suggesting that different factors affect the bone microstructure of these limb bones, 2) primate species with different positional behavior express different distributions of osteonal bone and these differences reflect body size and mechanical usage, 3) after sexual maturation age does not affect intraspecific variations in the percentage of osteonal bone, 4) osteon area scales positively allometrically on body size (cortical area) suggesting that the rate of osteon area increases faster than the rate of increase in body size among primate species. Other conclusions have been drawn from this study, the most important point of which is that mechanical loading plays a large role in stimulating secondary osteon formation and that osteonal bone distribution reflects positional behavior and body size. This has profound implications for how future primate histological research can be conducted. The results of this study also have implications for the application of histological analysis to extinct primate specimens. Overall, this information will give primatologists additional important tools to be used in examining skeletal form as it relates to function in both living and extant primate species.
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    Code and Sample Data for "Mesoscale Polymer Ribbon Arrays: High Aspect Ratio Surface Structures and their Digital Reconstruction"
    (2024-07-11) Moed, Demi E.; Dimitriyev, Michael S.; Greenvall, Benjamin R.; Grason, Gregory M.; Crosby, Alfred J.
    Mesoscale polymer ribbon arrays are high aspect ratio surface structures that exhibit unique three-dimensional morphologies in aqueous environments. To better correlate the impact of processing and aging on the morphology of these and similar high-aspect ratio surface structures, we have developed a MATLAB code capable of extracting quantitative morphological descriptors from 3D confocal microscopy data. This code was used to produce the results outlined in “Mesoscale Polymer Arrays: High Aspect Ratio Surface Structures and Their Digital Reconstruction.” In addition to this code, we have included instructions for data processing and four test datasets. This process first skeletonizes .tif stacks obtained via confocal microscopy. It then builds a model of individual ribbon positions in 3D space. Finally, it calculates key quantitative morphological descriptors such as the radius of curvature and end-to-end distance of these high aspect ratio structures.
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    A Category of Sample Spaces
    (1971) Collins, Walter Robert
  • Publication
    Consistency Among States in Evaluating the Risk of Nonnative Plants
    (2021) Kesler, Ben
    Invasive plants are non-native species that have self-sustaining populations, are spreading into natural areas, and have negative impacts on native ecosystems. An invasive plant that invades one state could quickly spread to surrounding states, so communication and collaboration between multiple states are needed to reduce risk from plant invasions in the U.S. Variations in weed risk assessments (WRAs) used for different states, however, may hinder consistency if WRAs produce different outcomes about which species are invasive. Additionally, it is more effective to prevent a species from becoming widespread than to manage an already-widespread species, so evaluating and regulating invasive species proactively (before they become widespread) would reduce later control costs. Evaluating new, range-shifting invasive species could lead to proactive regulation in light of climate change, but climate change is rarely considered explicitly in existing WRAs. Here, I assessed the consistency of state WRAs to one another as well as whether WRAs can account for range-shifting species proactively. I compared each state’s WRA to the standards laid out by Roy et al. (2018). My analysis determined whether WRAs for 30 states assess similar risk criteria and whether they have the flexibility to potentially incorporate climate change. Species’ spread, impacts, and potential distribution were included in all WRAs whereas species’ native range, introduction pathways, and potential effects in light of climate change were included in less than ten WRAs. Ten out of the 27 states that did not explicitly consider climate change in their WRAs could provide guidance that enables its consideration.