Browsing by Subject "Nutrients"

Now showing 1 - 3 of 3
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    PALEOPRODUCTIVITY VARIATIONS IN THE EASTERN CENTRAL EQUATORIAL PACIFIC OCEAN ON GLACIAL TIMESCALES
    (2008-08-22T14:19:57Z) Hale, Sarah Beth; Filippelli, Gabriel M.; Licht, Kathy J.; Swope, R. Jeffery
    Paleoproductivity records during the late Pleistocene are sparse. The equatorial Pacific and the Southern Ocean are collectively responsible for the majority of the new production in the oceans. The nutrient and carbon mass balances of these regions must be constrained in order to fully understand net global biological productivity on glacial timescales. The geochemistry of two east-central equatorial Pacific Ocean cores (02° 33.48 N; 117° 55.06 W) and (00° 15.42 S; 113° 00.57 W) are used to examine changes in biological productivity due to nutrient upwelling on glacial timescales during the Pleistocene. The cores were recovered in March 2006 on the AMAT03 cruise, a site survey cruise for IODP Proposal 626. The total concentrations of Ca, Ti, Fe, Al, P, Ba, S, Mg, Sr, Zn and Mn were determined by a total sediment digestion followed by analysis by inductively coupled plasma-atomic emission spectrometry (ICP). Original solid forms of P for 34 evenly spaced samples throughout one core were determined using the P Sequential Extraction technique. This study is attempting to compare upwelling and productivity records by determining temporal records of nutrient proxies, using Latimer and Filippelli (2006) which focused on the Southern Ocean. Equatorial upwelling and Southern Ocean upwelling both appear to exhibit strong glacial timescale variability. The P geochemistry results indicate that the P signal is largely biological. The equatorial Pacific evidence, in accordance with Southern Ocean patterns, supports a nutrient budget-driven productivity signal over time. Gabriel M. Filippelli, Ph. D, Committee Chair
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    Predicting Water Quality By Relating Secchi Disk Transparency Depths To Landsat 8
    (2015-08) Hancock, Miranda J.; Lulla, Vijay O.; Johnson, Daniel P. (Daniel Patrick), 1971-; Bein, Frederick L. (Frederick Louis), 1943-
    Monitoring lake quality remotely offers an economically feasible approach as opposed to in-situ field data collection. Researchers have demonstrated that lake clarity can be successfully monitored through the analysis of remote sensing. Evaluating satellite imagery, as a means of water quality detection, offers a practical way to assess lake clarity across large areas, enabling researchers to conduct comparisons on a large spatial scale. Landsat data offers free access to frequent and recurring satellite images. This allows researchers the ability to make temporal comparisons regarding lake water quality. Lake water quality is related to turbidity which is associated with clarity. Lake clarity is a strong indicator of lake health and overall water quality. The possibility of detecting and monitoring lake clarity using Landsat8 mean brightness values is discussed in this report. Lake clarity is analyzed in three different reservoirs for this study; Brookeville, Geist, and Eagle Creek. In-situ measurements obtained from Brookeville Reservoir were used to calibrate reflectance from Landsat 8’s Operational Land Imager (OLI) satellite. Results indicated a correlation between turbidity and brightness values, which are highly correlated in algal dominated lakes.
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    Salicylate administration suppresses the inflammatory response to nutrients and improves ovarian function in polycystic ovary syndrome
    (American Physiological Society, 2020-10) González, Frank; Mather, Kieren J.; Considine, Robert V.; Abdelhadi, Ola A.; Acton, Anthony J.; Medicine, School of Medicine
    Oxidative stress (OS) and inflammation are often present in polycystic ovary syndrome (PCOS). We examined the effects of salsalate treatment on nutrient-induced OS and inflammation, ovarian androgen secretion, ovulation, and insulin sensitivity in PCOS. Eight lean insulin-sensitive women with PCOS and eight age- and body composition-matched ovulatory controls for baseline comparison participated in the study. The women with PCOS underwent a 12-wk treatment of salsalate, a nonsteroidal anti-inflammatory drug, at a dose of 3 g daily. Markers of OS and inflammation were quantified in mononuclear cells (MNC) and plasma from blood drawn fasting and 2 h after saturated fat ingestion before and after treatment. Ovarian androgen secretion was assessed from blood drawn fasting and 24, 48, and 72 h after human chorionic gonadotropin (HCG) administration before and after treatment. Ovulation was documented based on biphasic basal body temperatures and luteal range progesterone elevations. A two-step pancreatic clamp was performed pre- and posttreatment to measure basal endogenous glucose production (EGP) and the steady-state glucose disposal rate (GDR) during the euglycemic phase and markers of OS and inflammation in MNC and plasma during the hyperglycemic phase. Salsalate administration suppressed lipid- and glucose-stimulated reactive oxygen species generation, activated nuclear factor-κB and circulating tumor necrosis factor-α, normalized basal androgen levels, and lowered HCG-stimulated androgen secretion without altering EGP or GDR. Four salsalate-treated subjects responded with two consecutive ovulations. We conclude that in PCOS, salsalate-induced suppression of OS and inflammation ameliorates ovarian androgen hypersecretion and may induce ovulation while maintaining insulin action.