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Short- and Long-Term Effects of Environmental Variability on the Ecophysiology of a Solitary Bee
Get PDFEnvironments can vary across seasons. One characteristic of spring in temperate regions is fluctuations in temperature. Sudden bouts of low temperature can have lasting effects on ectotherms that rely on ambient temperature. For developing insects, being unable to avoid or manage these low temperatures puts them further at risk. For example, Megachile rotundata undergo active development in the spring. Exposure to low temperatures as pupae for short periods does not decrease survival but does affect adult morphology. Pollination services may also be affected if temperatures are too low to promote flight in adults. The overall question is what are the short- and long-term physiological effects of temperature in pupae and adults? The first objective of this dissertation is to investigate the long-term effects of low temperature stress by measuring flight performance, reproductive output, and offspring characteristics. After receiving a constant low temperature for a week, females were less likely to nest and changed their offspring investment. Additionally, offspring of bees exposed to fluctuating low temperature stress were more likely to enter diapause despite being early in the season. The second objective was to test if oxygen consumption across temperatures generated a thermal performance curve as a short-term effect in M. rotundata pupae. Results indicate that oxygen consumption scales non-linearly like a thermal performance curve; however, the negative slope at high temperatures was not observed. The third objective was to determine how microclimate conditions affect flight initiation in M. rotundata adults. Two different activity boxes were designed to measure environmental variables and to manipulate cavity temperature. The first activity box measured several environmental variables and showed that even at very close proximities, M. rotundata experience different temperature conditions. In the other activity box design, internal cavity temperature was manipulated to increase early in the morning. Results show that increasing the cavity temperature promoted earlier flight and at lower ambient temperatures. This dissertation shows that the life stage an insect experiences a thermal stress can affect short- and long-term effects on physiology and life history in M. rotundata
Performance of Permutation Tests Using Simulated Genetic Data
Get PDFDisease statuses and biological conditions are known to be greatly impacted by differences in gene expression levels. A common challenge in RNA-seq data analysis is to identify genes whose mean expression levels change across different groups of samples, or, more generally, are associated with one or more variables of interest. Such analysis is called differential expression analysis. Many tools have been developed for analyzing differential gene expression (DGE) for RNA-seq data.
RNA-seq data are represented as counts. Typically, a generalized linear model with a log link and a negative binomial response is fit to the count data for each gene, and DE genes are identified by testing, for each gene, whether a model parameter or linear combination of model parameters is zero.
We conducted a simulation study to compare the performance of our proposed modified permutation test to DESeq2 edgeR, Limma, LFC and Voom when applied to RNA-seq data. We considered different combinations of sample sizes and underlying distributions. In this simulation study, we first simulated data using Monte Carlo simulation in SAS and assessed True Detection rate and False Positive rate for each model involved. We then simulated data from real RNA-seq data using SimSeq algorithm and compared the performance of our proposed model to DESeq2 edgeR, Limma, LFC and Voom.
The simulation results suggest that Permutation tests are a competitive alternative to traditional parametric methods for analyzing RNA-seq data when we have sufficient sample sizes. Specifically, the results show that Permutation controlled Type I error fairly well and had a comparable Power rate. Moreover, for a sample size n?10 simulation exhibited a comparable True detection rate and consistently kept the False Positive rate very low when sampling from Poisson and Negative Binomial distributions. Likewise, the results from SimSeq confirm that Permutation tests do a better job at keeping the False Positive rate the lowest
A Domain-Knowledge Modeling of Hospital-Acquired Infection Risk in Healthcare Personnel From Retrospective Observational Data: A Case Study for Covid-19
Get PDFHealthcare personnel (HCP) is facing a consistent risk of viral infections. We proposed a domain-knowledge-driven infection risk model to quantify the individual HCP and the population-level risks. For individual-level risk estimation, a time-variant model was proposed to capture the disease transmission dynamics. At the population-level, the infection risk was estimated using a Bayesian network model constructed from three feature sets. For model validation, we investigated the case study of the Coronavirus disease. The variance-based sensitivity analysis indicated that the uncertainty in the estimated risk was attributed to two variables: the number of close contacts and the viral transmission probability. We further validated the individual risk model by considering six occupations in the U.S. O*Net database. For the population-level risk model validation, the infection risk in Texas and California was estimated. The accurate estimation of infection risk will significantly enhance the PPE allocation, safety plans for HCP, and hospital staffing strategies
Soybean Iron Deficiency Chlorosis and Amaranthus Suppression by an Oat Companion Crop
Get PDFIron Deficiency Chlorosis (IDC) and weedy Amaranthus species are two production challenges affecting soybean production in North Dakota. Field experiments were conducted to evaluate the effect of an oat companion crop on soybean and to evaluate soybean preemergence herbicides effect on an oat companion crop and Amaranthus. An oat companion crop reduced IDC symptoms in one environment, but did not reduce IDC in others. An oat companion crop reduced Amaranthus biomass, but in many site years this suppression did not occur until soybean yield loss was realized. Flumioxazin and sulfentrazone consistently provided the greatest control of Amaranthus, but was also the most injurious to an oat companion crop. Greenhouse research evaluated competitiveness of two Amaranthus species, and factors tested did not influence competitiveness. Other forms of IDC and Amaranthus suppression may be more consistent with suppression and stable yields than that of an oat companion crop
Exploring Cover Crops for Managing Plant-Parasitic Nematodes Heterodera Glycines and Pratylenchus Penetrans
Get PDFThree studies were conducted to assess the effects of cover crops on plant-parasitic nematodes (PPNs) of potato and soybean. The first study investigated the hosting and population reduction abilities of 25 cover crops to Pratylenchus penetrans and found alfalfa (Bullseye) to reduce the initial population densities consistently. The second study tested the population reduction abilities of ten cover crops to two soybean cyst nematode (SCN; Heterodera glycines) populations in the microplot. Sunnhemp (cultivar not specified) was the most effective to reduce both SCN populations. The third study evaluated ten cover crops in a growth chamber for their impacts on hatching and root penetration of SCN and their potential as trap crops. Faba bean (Petite) showed the greatest potential to act as a trap crop for SCN, based on its effect on hatching and root penetration by SCN. These results help select suitable cover crops to manage PPNs in infested fields
Evaluation of Beef Cattle Temperament Using Infrared Thermography and Computer Vison Imaging Technologies
Get PDFThe aim of these studies are two-fold. The first, was to evaluate the use of infrared thermography (IRT) maximum, average, and minimum eye temperature (IRTMIN, IRTAVG, and IRTMAX, respectively) and percentage of eye white area (EW) to predict beef cattle temperament by assessing the relationship between IRT and EW traits with 4 established subjective and objective temperament scoring methods (n = 16 traits total). The second was to verify the feasibility of Video Technology (VT) as a measure of beef cattle temperament with minimal equipment and personnel and assess the accuracy and reliability of the VT measurements by comparing those with Temperament Score (TS) and Docility Score (DS). These studies showed potential in using eye white and video technology to objectively predict beef cattle temperament
Characterization of Inflationary and Deflationary Auscultatory Blood Pressure Measurements
Get PDFThis document is a paper-based dissertation. The dissertation is a collection of articles
written by the author in the pursuit to develop a novel method to measure blood pressure (BP).
The introduction chapter describes how the documents are interrelated. This work starts with the
description of the development and design of a non-invasive medical device capable of
measuring arterial BP with a combination of inflationary and deflationary procedures. In addition
to the device, we conducted a human-based study to characterize the properties of the BP signal
in the inflationary and deflationary curves. With the signals acquired, we focused on the
uncertainty occurring when taking two consecutive BP measurements.
The prototype was composed of 1) a modified off-the-shelf oscillometric BP system, 2) a
contact microphone with an amplifier, and 3) a high-sensitivity pulse oximeter, and its control
electronics. The device captured the cuff pressure signal, arterial skin-surface acoustics, and
photoplethysmography (PPG).
The captured signals were processed and analyzed. We focused our analysis on the
characterization of the uncertainty of two consecutive BP measurements by studying the biosignals
captured with the custom-made apparatus.
Accurate non-invasive BP measurements are vital in preventing and treating many
cardiovascular diseases. The ?gold standard? for non-invasive procedures is the auscultatory
method, which is based on detecting Korotkoff sounds while deflating an arm cuff. Using this
method as a ?gold standard? requires highly-trained technicians and has an intrinsic uncertainty
in its BP predictions. In this document, we analyze and characterize the origins of BP
uncertainty.
By analyzing the captured bio signals we postulate an uncertainty model for two
consecutive BP measurements. Our research group developed a computer-based simulation of
auscultatory BP measurement uncertainty, and these modeled results were compared to a humansubject
experiment with a group of 20 diverse-conditioned individuals.
Uncertainties were categorized and quantified. The total computer-simulated uncertainty
ranged between -8.4 mmHg to 8.4 mmHg in systolic BP and -8.4 mmHg to 8.3 mmHg in
diastolic BP at a 95% confidence interval. The limits in the human-based study ranged from -8.3
mmHg to 8.3 mmHg in systolic BP and -16.7 mmHg to 4.2 mmHg in diastolic BP
Athletic Trainers' Ability to Establish Peripheral Intravenous Access
Get PDFCertified athletic trainers (AT) are usually the first to respond to an athletic emergency heat illness (EHI) and are expected to provide prehospital care. The goal of this study was to investigate the percentage of athletic trainers who could successfully place an intravenous (IV) line and retain the skill for 30 days. Fifteen ATs received an educational training on how to place an IV from a nationally registered paramedic (NR-P) Those ATs who were successful in administering an IV were asked to report 30 days later for follow-up. Data were analyzed to compare IV placement success rates, confidence levels before and after each attempt, and ATs perceived value in the newly learned skill. The concept of ATs? success in IV placement will need additional study to help develop athletic training educational curricula and modify any prehospital care standards if necessary
Synthesis of Novel Biomass-derived Diol and Epoxide Monomers for Coatings Applications
Get PDFThere are few monomers or precursors in the polymer industry that are more ubiquitous than bisphenol A (BPA). According to the CDC, about 5-6 billion pounds of BPA are produced worldwide annually. For the synthesis of coatings and polymeric materials, BPA is polymerized directly as a diol into polycarbonates or, to a lesser extent, glycidated into an epoxy monomer or resin. For coatings applications, BPA epoxy resins are utilized in protecting metal cans from acidic foods and beverages to heavy machinery like farm equipment from weather-related corrosion. In part, this popularity has led to scrutiny of the popular monomer from a few different perspectives. Since BPA is petroleum-derived, there is an effort to find a renewably sourced alternative from a sustainability perspective. Additionally, the structural similarity of BPA and the hormone estradiol make BPA an endocrine disruptor. This combined with its widespread applications, means BPA could be a larger issue than previously understood.
To meet that challenge, many researchers, Sibi group included, have turned to biomass-derived ?building-block? chemicals. Biomass feedstocks contain unique structures not easily obtained from petroleum sources. While avoiding detrimental structure-activity relationships associated with BPA, the newly synthesized compound would need to retain or mimic the structure-property relationships of BPA-containing polymers for coatings applications.
The cellulosic monomer, 2,5-furandicarboxylic acid (FDCA), with exciting similarities to and some improvements upon petroleum-derived terephthalic acid was known, and its oxidative family of furans was being explored at the start of this project. A collection of furan diols was synthesized from 5-hydroxymethylfurfural (HMF), 2, 5-diformylfuran (DFF) and FDCA were synthesized by alkylation with various alkyl groups resulting in mono-, di-, and tetraalkylated diols, respectively. Depending on the alkyl group, certain materials properties were anticipated from these furanic diols.
The diols were screened for estrogenic, androgenic, anti-thyroid activity via CALUX assays. The cytotoxicity of the diols were also determined via cell death studies. From those results, few low molecular weight furan diols do not exhibit any observable activity as endocrine disruptors or an observable cytotoxicity. Subsequently, a selection of furanic diols were glycidated for use in epoxy coating synthesis
Evaluating Ornamental Grasses for the Challenging Rain Garden Environment
Get PDFFour experiments were conducted to determine the growth and survival of seven species of perennial ornamental grasses, tufted hairgrass [Deschampsia cespitosa (L.) P. Beauv.], switchgrass (Panicum virgatum L.), big bluestem (Andropogan gerardii Vitman), Chinese silvergrass (Miscanthus sinensis Andersson), little bluestem [Schizachyrium scoparium (Michx.) Nash], blue grama grass [Bouteloua gracilis (Kunth) Lag. ex Griffiths], and feather reed grass [Calamagrostis x acutiflora (Schrad.) Rchb.], when subjected to cyclical flood and drought, varying submergence depths and durations, NaCl, and NaCl with petroleum hydrocarbons. Chinese silvergrass and switchgrass survived cyclical soil flooding and drought and submergence for 7-d at a depth of 30 cm while maintaining an acceptable amount of foliar damage. All grasses survived cyclical flood and drought when the soil VWC was maintained at 14% suggesting all seven grasses can withstand periodic soil flooding as long as the water is not too deep. As water depth and duration increased from 4-d to 7-d, little bluestem, blue grama grass, and feather reed grass suffered significant foliar damage. Tufted hair grass and big bluestem suffered significant foliar damage when submerged for 2-d. Switchgrass and feather reed grass survived NaCl loads of up to 6.7 Mg?ha-1 and maintained a visual damage rating less than three making them suitable for planting in rain gardens or bioretention systems receiving NaCl runoff. Switchgrass also tolerated motor oil at rates up to 5% in combination with NaCl at rates up to 6.7 Mg?ha-1. Switchgrass would be an ideal grass for planting in areas receiving both contaminates. Tufted hair grass has limited tolerance to NaCl or motor oil and should not be planted in areas that may receive those contaminates in stormwater runoff. Big bluestem and little bluestem have limited tolerance to NaCl but some tolerance to motor oil and may be candidates for planting in areas receiving only motor oil in stormwater runoff. Chinese silvergrass and blue grama grass can tolerate moderate levels of NaCl and motor oil while maintaining a visual damage rating of four or less and would be candidates for planting in areas that receive moderate amounts of both pollutants in stormwater runoff