Browsing by Subject "Cycling"

Now showing 1 - 3 of 3
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    Carbon and Phosphorus Cycling in Arabian Sea Sediments across the Oxygen Minimum Zone
    (Longdom Publishing, 2017-11-09) Filippelli, Gabriel M.; Cowie, Gregory L.; Earth and Environmental Sciences, School of Science
    Several studies have focused on carbon, oxygen, and phosphorus dynamics across the modern oxygen minimum zone (OMZ) to constrain how signals of modern systems get “locked in” upon burial. In this study, a sequential phosphorus fractionation technique was applied to surficial and sub-surface sediments from stations at depths spanning the OMZ on the Pakistan margin of the Arabian Sea in order to test the oxygen-carbon-phosphorus connection in modern marine sediments. Some early diagenetic loss of phosphorus compared to organic carbon was observed, but a significant portion of the released phosphorus was retained by uptake on oxyhydroxides and by the formation of an authigenic phosphorus-bearing phase. This process is unaffected by station location relative to the OMZ, and results in an effective organic carbon-to-reactive-phosphorus sediment ratio that is close to the average observed for open-ocean sediments, regardless of bottom water oxygen content.
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    Navigating the shift: Supporting U.S. Paralympics Cycling through governance transition
    (2025) Hamilton, Jessica; Hull, Kristin; Department of Occupational Therapy, School of Health and Human Sciences; Lawless, Ian; Ryan, Jenny
    Paralympic sport represents the highest level of adaptive sports participation, where athletes compete internationally at elite levels. Currently, many Para-sports are undergoing a significant governance transition—from being managed internally by the United States Olympic & Paralympic Committee (USOPC) to being governed externally by their respective National Governing Bodies (NGBs). This 14-week Doctoral Capstone Experience and corresponding project were completed in collaboration with U.S. Paralympics Cycling. The primary aim was to support a smooth and effective governance transition for Para-cycling through program evaluation and education, ultimately fostering organizational growth and enhancing athlete satisfaction. A case study was conducted to explore the attitudes, experiences, and priorities of Para-cyclists. Two major themes emerged: the need for greater assistance with equipment management and the importance of increased financial support. These findings, along with additional insights gathered throughout the project, informed the development of an educational toolkit designed to equip USA Cycling with the knowledge and resources necessary to support the unique needs of Para-cyclists. This toolkit serves as a foundational step in promoting a successful and sustainable governance transition.
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    Ventilatory Responsiveness during Exercise and Performance Impairment in Acute Hypoxia
    (Wolters Kluwer, 2021-02-01) Constantini, Keren; Bouillet, Anna C.; Wiggins, Chad C.; Martin, Bruce J.; Chapman, Robert F.; Medicine, School of Medicine
    Introduction: An adequate increase in minute ventilation to defend arterial oxyhemoglobin saturation (SpO2) during hypoxic exercise is commonly viewed as an important factor contributing to large inter-individual variations in the degree of exercise performance impairment in hypoxia. Although the hypoxic ventilatory response (HVR) could provide insight into the underpinnings of such impairments, it is typically measured at rest under isocapnic conditions. Thus, we aimed to determine whether 1) HVR at rest and during exercise are similar and 2) exercise HVR is related to the degree of impairment in cycling time trial (TT) performance from normoxia to acute hypoxia (∆TT). Methods: Sixteen endurance-trained men (V˙O2peak, 62.5 ± 5.8 mL·kg-1·min-1) performed two poikilocapnic HVR tests: one during seated rest (HVRREST) and another during submaximal cycling (HVREX). On two separate visits, subjects (n = 12) performed a 10-km cycling TT while breathing either room air (FiO2 = 0.21) or hypoxic gas mixture (FiO2 = 0.16) in a randomized order. Results: HVREX was significantly (P < 0.001) greater than HVRREST (1.52 ± 0.47 and 0.22 ± 0.13 L·min-1·%SpO2-1, respectively), and these measures were not correlated (r = -0.16, P = 0.57). ∆TT was not correlated with HVRREST (P = 0.70) or HVREX (P = 0.54), but differences in ventilation and end-tidal CO2 between hypoxic and normoxic TT and the ventilatory equivalent for CO2 during normoxic TT explained ~85% of the variance in performance impairment in acute hypoxia (P < 0.01). Conclusion: We conclude that 1) HVR is not an appropriate measure to predict the exercise ventilatory response or performance impairments in acute hypoxia and 2) an adequate and metabolically matched increase in exercise ventilation, but not the gain in the ventilatory response to hypoxia, is essential for mitigating hypoxia-induced impairments in endurance cycling performance.