Physical Sciences and Mathematics Commons^™

A 60- Year Record Of The Demotechnic Index Of States, 1960-2019, Gavin James Kellough

Graduate Theses and Dissertations

A country’s dependency on energy resources can be interpreted through the calculation of energy indices. The Demotechnic Index (DI) was used to determine the trajectory of energy efficiency of each state in the United States over the period 1960-2019. The DI serves as a measure of the energy intensity of states and a proxy for energy sustainability of each state.The DI is the ratio of total energy use to total metabolic energy demand of a population. Mathematically, DI = (E_T-E_M)/E_M E_T represents the total energy used (metabolic energy + technological energy in kilojoules annually, kJ/y), while EM represents the basic …

Data Analytics For Sustainable Food And Agriculture Systems, Megan Lord Reavis

Graduate Theses and Dissertations

The increasing concentration of anthropogenic greenhouse gases in the atmosphere is altering the climate, posing a serious threat to global agriculture and food security. Agriculture and food production contribute a quarter of all GHG emissions produced, so there is a critical need to limit emissions in this area while increasing food production to feed the anticipated 10 billion people by 2050. To address the needs of the future, data-driven solutions are needed to guide decision-making and provide support for actionable climate mitigation and survival strategies. Research efforts must be focused on analyzing problems on multiple scales, identifying new ways to …

Strategies To Improve Forage Utilization By Sheep Offered Forage Mixtures, Valens Niyigena

Graduate Theses and Dissertations

In the first experiment, alfalfa and novel endophyte-infected tall fescue (NE+) forages were harvested after a killing frost, then mixed to formulate 4 different treatments; alfalfa alone, 67% alfalfa +33% fescue, 33% alfalfa + 67% fescue, or 100% fescue. After 3 months of storage as silage, Dorper ewe lambs (n = 20; mean BW = 34.7 ± 6.65 kg) were fed silage for ad libitum consumption, using 5 animals per treatment. Increasing the proportion of NE+ tall fescue improved (P < 0.05) silage total acids and lactic acid concentrations and decreased silage ammonia concentration. Digestible dry matter and organic matter intake and nitrogen utilization parameters decreased with increasing inclusion of NE+ in diet. In the second experiment, 16 Dorper ewe lambs (41.8 ± 4.61 kg BW) were assigned to 4 different treatments; alfalfa silage alone (0 g/kg; CONT) or alfalfa silage mixed with chopped sericea lespedeza (SL) hay to provide 90 (LOW), 180 (MED), or 270 g/kg SL (HIGH) on a dry matter basis in a randomized complete block design experiment with 2 period to provide 4 observations per treatment for each experimental period. Increasing the proportion of sericea lespedeza in the diet decreased dry matter and organic matter digestibility but did not affect feed intake. Fecal nitrogen (g/kg N intake) increased linearly (P < 0.01) while urinary N (g/ day and g/ kg of N intake) tended to decreased linearly and quadratically (P ≤ 0.1) with increasing the proportion of SL in diet. In the third experiments, 16 gestating Dorper ewe lambs (49.1 ± 4.61 kg BW) were allocated to 4 treatments; alfalfa silage alone (0% g/kg; CONT) or alfalfa silage mixed with lablab purpureus(LP) hay to provide 90 (LOW), 180 (MED), or 270 g/kg LP (HIGH) on a dry matter (DM) basis, in a randomized complete block design experiment with a total 8 replication per treatment. Supplementation of LP in diet increased quadratically (P ≤ 0.04) forage dry matter, organic matter intake, digestible dry matter and digestible organic matter intake (P < 0.05). Nitrogen apparently absorbed and urinary N both decreased linearly (P < 0.01) with adding more LP hay in diet. Harvesting and mixing alfalfa and fescue after a killing frost improved silage fermentation characteristics and supplementation of tannins from SL and polyphenol from LP altered N excretion.

Key words: lablab, sericea lespedeza, alfalfa silage, nitrogen, sheep.

Keeping Pace With Relative Sea Level Rise: Marsh Platform Monitoring Shows Minimal Sediment Deficit Along The Louisiana Coast, Kelly Marie Sanks

Graduate Theses and Dissertations

Recent reports estimate that the marshes of the Mississippi Delta receive just 30% of the sediment necessary to sustain current land area1. An extensive monitoring campaign by the USGS and LCPRA provides direct measurements of sediment accumulation, subsidence rates, and deposit characteristics along the coast over the past 10 years2, allowing us to directly evaluate this sediment balance. By interpolating bulk density, organic fraction, and vertical accretion rates from 273 sites, a direct measurement of organic and inorganic sediment accumulation can be made. Results show that a total of 82 MT/year of sediment is delivered to the coast. Using a …