ESTIMATION OF ECONOMIC RENT AS A MEASURE OF FACTOR OWNERS' WELFARE

Institutional and Behavioral Economics,

SOCIAL SUBSIDIES, ENVIRONMENTAL POLLUTION, AND UTILIZATION OF AGRICULTURAL WASTES: AN OREGON EXAMPLE

Environmental Economics and Policy,

New shield for gamma-ray spectrometry

Gamma-ray shield that can be evacuated, refilled with a clean gas, and pressurized for exclusion of airborne radioactive contaminants effectively lowers background noise. Under working conditions, repeated evacuation and filling procedures have not adversely affected the sensitivity and resolution of the crystal detector

Ground-state of graphene in the presence of random charged impurities

We calculate the carrier density dependent ground state properties of graphene in the presence of random charged impurities in the substrate taking into account disorder and interaction effects non-perturbatively on an equal footing in a self-consistent theoretical formalism. We provide detailed quantitative results on the dependence of the disorder-induced spatially inhomogeneous two-dimensional carrier density distribution on the external gate bias, the impurity density, and the impurity location. We find that the interplay between disorder and interaction is strong, particularly at lower impurity densities. We show that for the currently available typical graphene samples, inhomogeneity dominates graphene physics at low ($\lesssim 10^{12}$ cm$^{-2}$) carrier density with the density fluctuations becoming larger than the average density.Comment: Final version, accepted for publication in Phys. Rev. Let

Vitreous GeO2 response to shock loading

Shock wave profiles in vitreous GeO2 (6.56 Mg/m^3) under planar loading were measured using stress gauges to 14 GPa. New and previous data yield Hugoniot: D=0.974 (km/s)+1.711 u for shocks of 6 to 40 GPa. We show that the phase change from 4- to 6-fold coordination of Ge+4 with O–2 in vitreous GeO2 occurs from 4 to 15 GPa. Hugoniots of vitreous GeO2 and SiO2 are found to approximately coincide if the pressure in SiO2 is scaled by the ratio of SiO2 to GeO2 initial density

A Tale of Two Schools: A Practitioner’s Use of Bourdieu’s Theory to Understand Academic Underachievement Among Students at His Inner-City School

This paper describes my journey, as a teacher at a Canadian inner-city elementary school, toward conceptually understanding why many children at my current school repeatedly academically underachieve. I have utilized Bourdieu’s theory of practice as a heuristic to examine how social reproduction operates differently for school children from different social classes and leads to differences in achievement. The first component of this paper establishes a crucial theoretical base for practitioners by describing theory of practice and its key concepts of cultural capital, habitus, field, and symbolic violence, to explicate how social reproduction functions in education, highlighting the roles of institutions and professionals, and the transformative and generative potentials of Bourdieu’s theory. The second component provides important epistemological and methodological considerations regarding how practitioners might conduct successful empirical studies while avoiding the problems that are prevalent in existing empirical literature

Modeling for thermal resistance of non-O157 shiga toxin producing Escherichia coli in ground beef

Predictive models in microbiology are used for estimating the growth or survival of microorganism in a set of environmental conditions. A validated predictive model provides an alternative to extensive survival and shelf life studies. In this study, a predictive inactivation model for non-O157 shiga toxin producing Escherichia coli (STEC) in ground beef was developed. Six strains of non-O157 STEC; E. coli O26:H1, E. coli O45:H2, E. coli O103:H2, E. coli O111:H8, E. coli O121:H9, and E. coli O145: nonmotile, has similar pathogenicity as E. coli O157:H7 and can cause serious food borne illnesses. These pathogens are considered as an adulterant in meat products. The thermal behavior these non-O157 STECs was studied in laboratory media as well as in ground beef with varying fat content. There was no significant difference in the heat resistance among the strains, therefore, a cocktail of the strains was used for ground beef study. Ground beef fat content levels of 5, 10, 15, 20, 25, and 30% were used. Survival curves were generated between surviving population against time during heat treatment at five temperatures 55, 60, 65, 68, 71.1ºC. The shape of survival curves was analyzed by statistical analysis software (SAS®) to identify the best fitting primary model. The survival of these pathogens was modeled as a second order polynomial function of fat content of ground beef and temperature of cooking. The accuracy factor of the developed model was 11.43%, which is in the acceptable limit of 25%. The model was successfully validated for predicting process lethality in ground beef obtained from three grocery stores

Zero length crosslinking of bovine carbonic anhydrase II and chondroitin-4-sulfate

Bovine carbonic anhydrase II (EC 4.2.1.1) was covalently linked to chondroitin-4-sulfate (β-glucoronic acid-[1-3]-N-acetyl-β-galactosamine-4-sulfate-[1-4]) from bovine trachea. A zero length crosslinking procedure which reacts the protein amino groups with preactivated carboxyl groups of chondroitin-4-sulfate was carried out with l-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide as coupling agents. The complex remained enzymatically active, was water soluble, and appeared to be about 170 kDa as analyzed on SDS-PAGE and column chromatography on Sephadex G 150. It is likely that 5 protein molecules (30 kDa each) are linked to 1 chondroitin-4-sulfate molecule (20 kDa). The CO2 hydration activity of the complex was generally slightly less than the unmodified protein with both forms having highest activity at a pH 8 and the lowest activity at pH 5.5. The same was true for the kinetic parameters kcat and kcat / KM. The pH dependence of kcat was not affected upon conjugation with chondroitin-4-sulfate. The KM appeared to be slightly less for the modified form of the enzyme for the hydration of CO2 at all pH values used. For the dehydration of bicarbonate at pH 5.5 (room temperature), the KM was also slightly less for the modified enzyme (KM = 21.7 mM) as compared to the unmodified form (KM = 24.2 mM). The complex also appeared to be capable of hydrating CO2 in human plasma and seemed to be more resistant of inhibitory effects of plasma as compared to the unmodified enzyme. The effects of a noncompetitive inhibitor, acetazolamide, were similar between the crosslinked complex (KI = 3.87 x 10-8 M) and the unmodified enzyme (KI = 4.62 x 10-8 M). However, the modified enzyme was more resistant to denaturation by guanidine hydrochloride, SDS and heat. Covalent coupling of chondroitin-4-sulfate to enzymes may present a method with which the stabilization of biological structures can be achieved with a minimal (if any) loss of enzymatic activity. The BCA II : chondroitin-4-sulfate complex produced in this work may be of use as an artificial blood substitute designed to transport CO2 molecules in vivo

Characterization of resistance to Fusarium head blight in bread and durum wheat

Fusarium head blight (FHB) caused primarily by Fusarium graminearum (Fg) Schwabe (telomorph: Gibberella zeae Schw. [Petch]) in North America, is one of the most devstating diseases of wheat in Canada. An integrated approach to manage this disease is recommended that combines the adoption of cultural practices (tillage and crop rotation), cultivar resistance, and fungicide application at recommended timings. Resistance to FHB in wheat is a quantitatively inherited trait and highly influenced by environmental conditions. Sources of resistance are available in common wheat but not for durum wheat. There are no commercially available durum cultivars which are moderately resistant in North America which in part, can be explained by a lack of resistance in the primary gene pool. The current study was designed to study the effects (on disease suppression and linkage-drag associated with introgressions) of Sumai 3 derived Fhb1, Fhb2, and Fhb5 genes in hard red spring wheat cultivars [near-isogenic lines (NILs) developed in CDC Go and CDC Alsask backgrounds] from western Canada, the interaction of Fhb1 and Fhb5 with metconazole fungicide, and the mapping of quantitative trait loci (QTL) from emmer and durum wheat lines. The last part of the study utilized X-ray computed tomography as a tool to image selected NILs in the CDC Alsask background and focused on identification of key tissues conferring Type-II resistance to Fg. The phenotypic response of NILs carrying combinations of Sumai 3-derived genes suggested non-additive responses and Fhb5 was as effective as Fhb1 in conferring field resistance in both populations. Four to five resistance improving alleles, other than Fhb1, Fhb2, and Fhb5, in both populations were identified and three of five in the CDC Go population were contributed by the susceptible parent. The regions carrying these resistance improving alleles encoded disease resistance proteins, protein kinases, nucleotide-binding and leucine rich repeats’ domains. Complex epistatic gene-gene interactions among marker loci (including Fhb1, Fhb2, Fhb5) explained >20% of the phenotypic variation in FHB infection measurements. For the linkage drag experiment, introgressions resulted in lower thousand kernel weight and increased plant height with Fhb5. Among end-use quality traits, SDS-sedimentation volume and grain protein content were affected. In addition to Fhb1, Fhb2, Fhb5, we identified 10 loci in CDC Alsask NILs and nine in CDC Go NILs that affected the traits measured and none of these additional loci were common in both populations indicating the presence of multiple alleles in exotic sources that can result in linkage drag. Linkage drag is largely dependent on genetic background and the proportion of donor resistance alleles, thus, we observed more adverse effects among CDC Alsask NILs than among CDC Go NILs. Improvements in FHB resistance can still be made by introgressing the major genes examined in this study by using marker-assisted selection and selecting rare segregants with improved agronomy and end-use quality. There was an additive effect of Sumai 3-derived genes with metconazole in suppressing FHB and deoxynivalenol (DON) accumulation in the grain. Despite higher fungicide efficacy on moderately susceptible (MS) genotypes, FHB severity was greater on MS as compared to moderately resistant (MR) genotypes. Application of fungicides is warranted even on MR cultivars under moderate and high FHB disease pressure to reduce the amount of Fusarium damaged kernels (FDKs) and DON accumulation. In the QTL mapping study of tetraploid wheat, fifteen QTL (derived from both parents) for FHB resistance were identified on 11 of the 14 chromosomes using saturated linkage maps and a majority of the QTL were consistently detected in multiple environments. The combination of four relative large-effect and promising QTL reduced field FHB index, severity, incidence and visual rating index by 59%, 48%, 30%, and 29%, respectively. The majority of the QTL reported in the current study are novel and represent narrow intervals between the flanking markers; therefore, marker-assisted selection shoulb be of value in breeding FHB resistant durum wheat cultivars. In the final study of this thesis, as a proof-of-concept, we showcased the successful use of synchrotron-based X-ray imaging techniques to study the wheat-Fg interaction. This work indicated/re-confirmed the structural role of rachilla and rachis nodes in Type-II resistance to Fg in wheat. The results from all these studies will help wheat breeders to make decisions on introgressing exotic FHB resistance genes into common wheat. Additionally, novel QTL identified in tetraploid wheat can be used to enhance resistance in elite durum wheat lines by marker-assisted selection