Determination of Three-Dimensional Grain Boundary Connectivity from Two-Dimensional Microstructures

The connectivity of so-called special and general grain boundaries at a quadruple node is known to be nonrandom as a result of crystallographic constraints. Although a quadruple node is a three-dimensional feature, there exist two-dimensional features which are topologically identical. Therefore, the distribution of these two-dimensional features may be used to determine the three-dimensional connectivity. Computer simulations of a three-dimensional microstructure which is virtually serial sectioned are used to validate the proposed approach

A survey of elementary school banking in New England

Thesis (Ed.M.)--Boston Universit

The Green's function for a plane contour

Thesis (PhD)--University of Illinois, 1918TypescriptVitaIncludes bibliographical reference

Molecular diversity and identification of alleles for Verticillium wilt resistance in elite cotton (Gossypium hirsutum L.) germplasm

Cotton is an important crop in the textile, food and pharmaceutical industries. In the present study, a panel of 108 elite cotton (Gossypium hirsutum L.) lines was genotyped with 177 genome-wide SSR markers to assess genetic diversity, linkage disequilibrium, population structure and association analyses. A total of 967 loci were assayed and the lines fell into four main groups with a mean genetic distance of 39%. The linkage disequilibrium (LD) decay rate was estimated to be 20–30 cm (r2 ≤ 0.5). Association analyses were performed with both general linear model and mixed linear model methods to identify SSR marker loci linked to Verticillium wilt resistance. Verticillium wilt is a fungal disease that causes huge yield losses in cotton production throughout the world. A total of 26 marker loci distributed on 14 chromosomes were associated with resistance at p ≤ 0.05. Eight of the 26 associated marker loci were highly significant (p < 0.01). The phenotypic variation explained (r2) by individual markers ranged from 3.2% to 8.2%. Three of the 26 marker loci (JESPR153, JESPR274 and CIR218) were consistent with previous studies. Our results should be useful in improving Verticillium wilt resistance in cotton breeding lines.GDARP (General Directorate of Agricultural Research and Policies, Ministry of Food, Agriculture and Livestock Republic of Turkey) (TAGEM-11/AR-GE/17

Knowledge Surveys

A knowledge survey consists of course learning objectives framed as questions and is given before and after the content of the knowledge survey is presented in class. For each question on the knowledge survey, students respond using a three-point rating of their confidence to correctly answer the question. Knowledge surveys may be used as a pretest before the semester or a new unit begins to help faculty get a sense of what students believe they know about upcoming topics. Knowledge surveys may be conducted electronically through Blackboard or as an in or out of class assignment on paper

Correlations Beyond the Nearest-Neighbor Level in Grain Boundary Networks

Correlations among \u27special\u27 and \u27general\u27 grain boundaries are studied on two-dimensional networks, by examining the configurational entropy of boundary structures as well as percolation thresholds. Consideration of crystallographic constraints at various length scales reveals that higher-order constraints play a role in boundary connectivity and network structure. Implications for grain boundary engineering are discussed and directions for future work highlighted

Bacterial wilt resistance in tomato, eggplant and pepper : genetic resources challenged with the multifaceted Ralstonia solanacearum species complex : [P3-49]

Bacterial wilt caused by strains belonging to the #Ralstonia solanacearum# species complex inflicts severe economic losses in many crops worldwide. Host resistance remains the most effective control strategy against the bacterial wilt. However, interactions among plant, strain and environment often result in overcoming resistance properties due to variation in strain pathogenicity and adaptation. To help breeders circumvent this problem, we assembled a worldwide collection of 30 accessions of Tomato, Eggplant and Pepper (Core-TEP) that are commonly used as sources of resistance to #R. solanacearum# or for mapping QTLs. The Core-TEP lines were challenged with a core collection of 12 pathogen strains (Core-Rs2) representing the phylogenetic diversity of #R. solanacearum#. To our knowledge, this is the first study that investigated bacterial wilt resistance in a set of worldwide genetic resources used as sources of resistance in three solanaceous species (tomato, eggplant, and pepper). Our results showed that none of the Core-TEP accessions, representative of the TEP genetic diversity for resistance, was resistant to all Core-Rs2 strains. Hence, none of them displayed universal resistance. We observed six wilt interaction phenotypes, from highly susceptible to highly resistant. Intermediate phenotype resulted from the ability of plants to tolerate latent infections, i.e. bacterial colonization of vascular elements with limited or no wilting. #R. solanacearum# strains exhibited specific patterns of interaction with Core-TEP accessions. Thanks to several similarities of virulence patterns between strains of Core-Rs2, we defined two working concepts associated with two levels of resolution of the interactions between strains and plant phenotypes. One concept, the "pathoprofile" is based on the interactions for the three solanaceae taken together, and the other, the pathotype is based on the interactions for each plant species taken separately. The 12 Core-Rs2 strains partitioned into four pathotypes on Pepper accessions, five pathotypes on Tomato, six pathotypes on Eggplant, and six pathoprofiles on the whole set of Core-TEP accessions. Neither pathotypes nor pathoprofiles were phylotype-specific. Pathoprofiles with high pathogenicity were mainly found in strains from phylotypes I, IIB and III. One pathoprofile included a strain that overcame almost all resistance sources. (Résumé d'auteur

Correlation-Space Description of the Percolation Transition in Composite Microstructures

We explore the percolation threshold shift as short-range correlations are introduced and systematically varied in binary composites. Two complementary representations of the correlations are developed in terms of the distribution of phase bonds or, alternatively, using a set of appropriate short-range order parameters. In either case, systematic exploration of the correlation space reveals a boundary that separates percolating from nonpercolating structures and permits empirical equations that identify the location of the threshold for systems of arbitrary short-range correlation states. Two- and three-dimensional site lattices with two-body correlations, as well as a two-dimensional hexagonal bond network with three-body correlations, are explored. The approach presented here should be generalizable to more complex correlation states, including higher-order and longer-range correlations

Effects of Crystallographic Orientation on the Early Stages of Oxidation in Nickel and Chromium

Surface orientation plays an important role in the oxidation behavior of single crystals where studies have found the relative oxidation rates for surfaces with different orientations. However, most materials are polycrystalline and contain myriad orientations that contribute to the overall oxidation process. Here we determine the effects of orientation on the early stages of oxidation behavior as a function of surface orientation for polycrystalline nickel (face-centered cubic) and chromium (body-centered cubic). After high temperature oxidation, the oxide topography is characterized using optical profilometry and the underlying microstructure is characterized with electron backscatter diffraction (EBSD). By correlating results from EBSD and optical profilometry, the oxide height is determined for each crystallographic orientation. In both Ni and Cr, a strong relationship is observed between the oxidation rate and direction of the surface normal; for Ni, (111) surfaces oxidize slowest, while (100) surfaces in Cr have the lowest oxidation rates. Although orientation-dependent oxidation rates are observed at short times, the effect is diminished at longer oxidation times

A measure of genetic diversity of goldenseal (Hydrastis canadensis L.) by RAPD analysis

Goldenseal (Hydrastis canadensis L.) is a medicinal plant valued for the treatment of sore eyes and mouths. Although cultivation of the plant has helped meet growing demand, goldenseal is still considered a threatened or endangered species throughout much of its range in North America. In an effort to assess possible conservation strategies for goldenseal genetic resources, levels of genetic diversity within and among cultivated and wild populations were quantified. RAPD analysis was used to examine six cultivated and 11 wild populations sampled from North Carolina, Ohio, Pennsylvania, and West Virginia. The average percentage of polymorphic bands in cultivated and wild populations was low (16.8 and 15.5 %, respectively), and geographic range did not predict the level of genetic diversity. Most of the genetic variation (81.2 %) was within populations; only 3.6 % was partitioned between cultivated and wild populations. Our results differed from a previous study which concluded that genetic differences were greater among than within populations. The results of the current study indicate that, although goldenseal grows clonally and in dense patches, a mixed mating system in which both selfing and outcrossing occur is also operating. We therefore suggest that the ex situ conservation of individual plants within populations, chosen carefully to account for clonal propagation in situ, is an appropriate strategy for sustaining the genetic diversity of goldenseal