Link Between Muscle and Whole-body Energetic Responses to Exercise

Substantial evidence exists regarding how skeletal muscles use energy and how this affects muscular performance. What remains unclear is how characteristics of muscle energetics affect whole-body energetics during daily living, and what effects this may have on mobility. The goal of this study was to determine the associations between muscle and whole-body energetics including the relationships between: 1) muscle PCr depletion (∆PCr) in response to light intensity isotonic contractions and the oxygen deficit at the onset of a 30-min treadmill walk (30MTW), and, 2) muscle oxidative capacity and excess post-exercise oxygen consumption (EPOC; 30MTW), respiratory exchange ratio (RER; 30MTW), and peak oxygen consumption (VO2 peak) from a graded treadmill test. Eight healthy young (28.4 ± 3.5 years) male participants were studied. Muscle energetics were measured via 31-Phosphorus magnetic resonance spectroscopy (31P-MRS). Muscle ∆PCr was determined as the change in PCr during 2-min of isotonic knee extensor contractions. Muscle oxidative capacity was determined as the rate constant (kPCr) of a PCr recovery following 24-s of maximal isokinetic knee extensor contractions. Whole-body energetic responses to the 30MTW were measured via indirect calorimetry. Oxygen deficit and EPOC were determined as the time constants of the change in oxygen consumption at the onset and offset of the 30MTW, respectively. Respiratory exchange ratio was determined as the mean RER during minutes 7-30 (RER L23), 25-30 (RER L5), and 29-30 (RER L1). Peak oxygen consumption was the highest 30-s average of oxygen consumption during a graded treadmill test, normalized to total mass and lean mass measured by dual-X-ray absorptiometry. Spearman rank correlation coefficients (rs) were calculated to evaluate the associations between independent variables (muscle ∆PCr and oxidative capacity) and dependent variables (oxygen deficit, EPOC, RER, and VO2 peak). Muscle ∆PCr had a positive association (rs = 0.46, p = 0.30) with oxygen deficit. Muscle oxidative capacity had a negative association with EPOC (rs = -0.64, p = 0.14), RER L23 (rs = -0.64, p = 0.14), L5 (rs = -0.68, p = 0.11), and L1 (rs = -0.74, p = 0.07). Muscle oxidative capacity had a positive association with VO2 peak per lean mass (rs = 0.64, p = 0.10), but not VO2 peak per total mass (rs = 0.14, p = 0.75). These results provide promising preliminary evidence that muscle energetics are associated with whole-body energetic response to daily-living type exercise

Investigation Of Pn Junction Delineation Resolution Using Electron Beam Induced Current

This dissertation will investigate electron beam induced current (EBIC) for determining semiconductor material and device parameters. While previous experimental work on PN junction delineation using EBIC with the scanning electron microscope has resulted in resolution to approximately 10 nm, theoretical study shows the potential use of EBIC for higher resolution (nanometer) PN junction and FET channel length delineation using the transmission electron microscope. Theoretical arguments using computer simulations of electron beam generation volume, collection probability and EBIC were performed and are presented for the purpose of determining EBIC use in a 300 keV transmission electron microscope (TEM) for PN junction depth determination. Measured results indicate that by measuring thin semiconductor samples with high surface recombination velocity and by using a narrow, high-energy electron beam in the STEM mode of a transmission electron microscope, nanometer resolution may be possible. The practical and experimental limits of beam energy and semiconducting material thermal damage will be discussed

Carbon Pricing in the Private Sector: How Science, Politics, and Climate Change Influence Business Strategy

The social cost of carbon (SCC) is defined as the monetized social (externality) cost of a metric ton of CO2 emitted into the atmosphere in a given year. Economist Michael Greenstone called it “The most important figure you’ve never heard of.” Since 2009, the SCC has been a major factor in $1.2 trillion of legislation. No carbon tax exists in the U.S., but many private and public companies have started using internal carbon pricing in decision making. The Carbon Disclosure Project (CDP) has capitalized on this trend by creating a central depository for emissions reporting and sustainability. This was the resource for our data analysis. Our research primarily uses the CDP and company sustainability reports to analyze the motives for carbon pricing in companies, the types of pricing used and the accuracy of carbon pricing evaluations

Carbon Pricing in the Private Sector: How the Science, and Politics, of Carbon Pricing and Climate Change Influence Business Strategy

Economist Michael Greenstone called the Social Cost of Carbon (SCC) “the most important figure you’ve never heard of”. The EPA defines the SCC as “an estimate of the economic damages associated with a small increase in carbon dioxide (CO2) emissions, conventionally one metric ton, in a given year.” The dollar figure assigned therefore represents “the value of damages avoided for a small emission reduction (i.e. the benefit of a CO2 reduction).” The current dollar value has different estimates in each state and within each company. The process of calculating the SCC is immensely complex and relies on numerous variables that are highly disputed by scientists, private interest groups and policy makers. Our purpose is to examine motives and trends behind public and private companies using SCC estimates

A surface circulation study in middle Elizabeth River

A new oil refinery has been proposed to be located in Portsmouth, Virginia south of the Hampton Roads area. The Virginia Institute of Marine Science was asked by NUS Corporation to conduct a surface circulation study to assemble the characteristics of the flow near Lambert Point on the Elizabeth River (Figure 3.1). This report includes a review of the previous work in the area, a description of the particular experiments performed, and an interpretation of the data in terms of surface circulation. Several small oil slicks were incidentally observed during the experiments and their behavior has been discussed in relation to the observed surface circulation

Sequential Experimental Design for Predator-Prey Functional Response Experiments

Understanding functional response within a predator-prey dynamic is a cornerstone for many quantitative ecological studies. Over the past 60 years, the methodology for modelling functional response has gradually transitioned from the classic mechanistic models to more statistically oriented models. To obtain inferences on these statistical models, a substantial number of experiments need to be conducted. The obvious disadvantages of collecting this volume of data include cost, time and the sacrificing of animals. Therefore, optimally designed experiments are useful as they may reduce the total number of experimental runs required to attain the same statistical results. In this paper, we develop the first sequential experimental design method for predator-prey functional response experiments. To make inferences on the parameters in each of the statistical models we consider, we use sequential Monte Carlo, which is computationally efficient and facilitates convenient estimation of important utility functions. It provides coverage of experimental goals including parameter estimation, model discrimination as well as a combination of these. The results of our simulation study illustrate that for predator-prey functional response experiments sequential design outperforms static design for our experimental goals. R code for implementing the methodology is available via https://github.com/haydenmoffat/sequential_design_for_predator_prey_experiments.Comment: Main Text: 23 pages, 7 Figures - Supplementary Text: 11 pages, 5 Figure