Nontrivial Galois module structure of cyclotomic fields

We say a tame Galois field extension $L/K$ with Galois group $G$ has trivial Galois module structure if the rings of integers have the property that \Cal{O}_{L} is a free \Cal{O}_{K}[G]-module. The work of Greither, Replogle, Rubin, and Srivastav shows that for each algebraic number field other than the rational numbers there will exist infinitely many primes $l$ so that for each there is a tame Galois field extension of degree $l$ so that $L/K$ has nontrivial Galois module structure. However, the proof does not directly yield specific primes $l$ for a given algebraic number field $K.$ For $K$ any cyclotomic field we find an explicit $l$ so that there is a tame degree $l$ extension $L/K$ with nontrivial Galois module structure

Manifest Needs of Women in Male-Intensive Professions: A Replication Study

published or submitted for publicatio

Computer simulation of the heavy-duty turbo-compounded diesel cycle for studies of engine efficiency and performance

Reductions in heat loss at appropriate points in the diesel engine which result in substantially increased exhaust enthalpy were shown. The concepts for this increased enthalpy are the turbocharged, turbocompounded diesel engine cycle. A computer simulation of the heavy duty turbocharged turbo-compounded diesel engine system was undertaken. This allows the definition of the tradeoffs which are associated with the introduction of ceramic materials in various parts of the total engine system, and the study of system optimization. The basic assumptions and the mathematical relationships used in the simulation of the model engine are described

Application of manual control theory to the study of biological stress

A study was run using both a stable, third-order task and an adaptive first-order unstable task singly and in combination to test the effects of 2 min hypoxia (22000 ft) on human operator. The results indicate that the RMS error in the stable task does not change as a function of hypoxic stress whereas the error in an unstable task changes significantly. Models involving human operator parameter changes and noise injection are discussed

Encouraging Sustainable Transport Choices in American Households: Results from an Empirically Grounded Agent-Based Model

The transport sector needs to go through an extended process of decarbonisation to counter the threat of climate change. Unfortunately, the International Energy Agency forecasts an enormous growth in the number of cars and greenhouse gas emissions by 2050. Two issues can thus be identified: (1) the need for a new methodology that could evaluate the policy performances ex-ante and (2) the need for more effective policies. To help address these issues, we developed an Agent-Based Model called Mobility USA aimed at: (1) testing whether this could be an effective approach in analysing ex-ante policy implementation in the transport sector; and (2) evaluating the effects of alternative policy scenarios on commuting behaviours in the USA. Particularly, we tested the effects of two sets of policies, namely market-based and preference-change ones. The model results suggest that this type of agent-based approach will provide a useful tool for testing policy interventions and their effectiveness

Functional analysis of nematode secreted proteins to devise innovative approaches for plant resistance against nematodes [abstract]

Abstract only availableApproximately 1 billion dollars in soybean yield loss is caused annually in the US by a microscopic parasite known as the soybean cyst nematode (SCN; Heterodera glycines). My research is focused on studying cyst nematode parasitism genes. Cyst nematodes secrete proteins that originate from two sets of gland cells (dorsal and subventral) through a stylet (hollow feeding tube) directly into root tissues to facilitate plant parasitism and induce a feeding cell that is necessary to sustain nematode growth and development. Stylet-secreted proteins are encoded by nematode parasitism genes. My project specifically involves a SCN parasitism gene called Hg2D01. Hg2D01 is a secreted protein with an unknown function that is specifically expressed in the dorsal gland. Hg2D01 encodes a 186 amino acid protein with a signal peptide. Hg2D01 maintains greater than 90% nucleotide and amino acid identity with the Hs2D01 gene from the closely related beet cyst nematode (Heterodera schachtii), a parasite of Arabidopsis. Through quantitative real-time PCR I have determined that Hg2D01 is expressed in all life stages throughout the 30 day life cycle of the nematode, excluding non-feeding stages such as eggs, juveniles, and adult males. The fact that Hg2D01 is only expressed in feeding life stages suggests that it likely plays an important role during nematode feeding cell formation. To test this hypothesis, we are conducting a number of studies to determine the function of Hg2D01 that include generating constructs for ectopic expression in Arabidopsis and utilizing an in-planta based RNAi approach to knock-out Hg2D01. Plants expressing dsRNA (double-stranded RNA) specifically targeting Hg2D01 have been infected with nematodes and effects on parasitism are being assessed. These studies are providing important insight into the mechanisms of nematode pathogenesis of plants and will contribute essential knowledge to our long-term goal of developing nematode-resistant crop plants.MU Monsanto Undergraduate Research Fellowshi

Nematode secreted proteins originating from esophageal gland cells are injected through the stylet [abstract]

Abstract only availableFaculty Mentor: Melissa G. Mitchum, Division of Plant SciencesNematode secreted proteins originating from esophageal gland cells are injected through the stylet directly into root tissues to facilitate plant parasitism. Secreted proteins are encoded by parasitism genes expressed in the nematode esophageal gland cells. The soybean cyst nematode (Heterodera glycines) Hg2DO1 gene is a candidate parasitism gene specifically expressed in the dorsal gland that encodes a 186 amino acid protein with a signal peptide. The Hg2DO1 sequence is classified as a “pioneer gene” with no homology to any other sequences present in current databases. We have determined the genomic structure of the Hg2DO1 gene and isolated both genomic DNA and corresponding cDNA sequences from the closely related nematode, Heterodera schachtii, for comparative analysis. Quantitative real-time PCR is underway to determine the developmental expression profile of the Hg2DO1 gene throughout nematode development. For functional analysis of Hg2DO1 both overexpression and RNAi constructs were generated and used to transform Arabidopsis and soybean hairy roots. These plants are being assessed for phenotypic changes and effects on parasitism. These studies are providing important insight into the mechanisms of nematode pathogenesis of plants.Nematode secreted proteins originating from esophageal gland cells are injected through the stylet directly into root tissues to facilitate plant parasitism. Secreted proteins are encoded by parasitism genes expressed in the nematode esophageal gland cells. The soybean cyst nematode (Heterodera glycines) Hg2DO1 gene is a candidate parasitism gene specifically expressed in the dorsal gland that encodes a 186 amino acid protein with a signal peptide. The Hg2DO1 sequence is classified as a “pioneer gene” with no homology to any other sequences present in current databases.  We have determined the genomic structure of the Hg2DO1 gene and isolated both genomic DNA and corresponding cDNA sequences from the closely related nematode, Heterodera schachtii, for comparative analysis. Quantitative real-time PCR is underway  to determine the developmental expression profile of the Hg2DO1 gene throughout nematode development. For functional analysis of Hg2DO1 both overexpression and RNAi constructs were generated and used to transform Arabidopsis and soybean hairy roots. These plants are being assessed for phenotypic changes and effects on parasitism. These studies are providing important insight into the mechanisms of nematode pathogenesis of plants

Natural Genetic Variation Affecting Calcium Homeostasis

Calcium (Ca) is essential for multiple functions within the body including skeletal health. The level of Ca in the serum is tightly regulated. During periods of habitual low Ca intake, the body senses a decrease in serum Ca and increases renal conversion of 25 hydroxyvitamin D (25(OH)D) to 1,25 dihydroxyvitamin D (1,25(OH)2D). 1,25(OH)2D acts through the vitamin D receptor (VDR) to increase intestinal Ca absorption, renal Ca reabsorption and skeletal Ca resorption. Efficient intestinal Ca absorption, especially during periods of low Ca intake, is critical for protecting bone mass. Ca absorption and its primary regulator, 1,25(OH)2D, are affected by both genetic and environmental factors. However, the genetic architecture of these phenotypes has not been carefully studied in a controlled environment. Using genetically characterized mouse models in a controlled environment the studies in this dissertation characterize the natural genetic variation affecting intestinal Ca absorption, 25(OH)D, and 1,25(OH)2D under normal and low dietary Ca conditions. This dietary intervention allowed for the study of gene-by-diet interactions (i.e. variability in the adaptation of these parameters to habitual low Ca intake). The relationship of Ca absorption to known regulators and cellular mediators is examined, elucidating significant effects of genetics on these relationships and identifying gaps in our current knowledge of intestinal Ca absorption. In addition, specific genetic loci affecting intestinal Ca absorption, 1,25(OH)2D, 25(OH)D, and diet-induced adaptation are identified in the mouse genome. These quantitative trait loci (QTLs) represent novel variation affecting Ca absorption and vitamin D metabolites. Identification of the causal variation underlying these QTLs will expand our knowledge of Ca homeostatic pathways. These studies serve as a foundation for identification of individual variation in Ca homeostasis and personalized dietary recommendations