Microstructure, crystallography and stable isotope composition of Crassostrea gigas

Many marine molluscs produce complex shells of calcium carbonate. These shells are formed under strict biological control to provide a range of functions to ensure the survival of the living organism. These inspiring biomineral structures can also provide an archive of environmental change via proxies such as δ18O and δ13C within the shell carbonate. However, the intimate relationship between the biological and environmental controls influencing biomineral production can often obscure the environmental signal, making it difficult to interpret environmental information from shell proxies. Understanding the design of biomineral structures will further our knowledge of biomineralisation as a whole, while understanding the controls that influence shell production will ensure that shell proxies applied to palaeoenvironmental studies are accurate. Oysters are sessile bivalve molluscs that have evolved since the Triassic and expanded to occupy a range of habitats with almost global distribution, providing an example of a highly successful biomineral system. This study investigates the ultrastructure, crystallography and stable isotope composition of the Pacific oyster, Crassostrea gigas from estuarine and marine environments. The method by which oysters adhere to hard substrates is also investigated. Both valves of the oyster shell are composed predominantly of low Mg calcite in three forms; an outer prismatic region, an inner foliated structure and chalk lenses which appear sporadically throughout the valves. Aragonite is restricted to the myostracum and parts of the hinge structure. Crystallographic analysis shows that, despite variations in structural morphology, the superimposed layers of the oyster shell maintain a single crystallographic orientation with the crystallographic c-axis orientated perpendicular to the outer shell surface. Varying crystal morphology, while maintaining crystallographic unity, may be a deliberate design to provide the oyster shell with both strength and flexibility. In general, there is no difference in the overall ultrastructure or microstructural arrangement of estuarine and marine oysters. Estuarine oysters contain significantly more chalk than marine equivalents suggesting that the appearance of chalk lenses is, to some degree, triggered by an external environmental stimulus. Stable carbon and oxygen isotope analysis of folia and chalk provides further insights into the appearance of chalk in the oyster shell structure. There is no significant difference in the isotope composition of folia or chalky layers, although patterns of δ13C and δ18O of folia and chalk reveal key differences between the two structures. Folia display a narrower range of δ18O values compared with chalk and exhibit significant interspecimen variation with respect to δ13C. Interspecimen variation, with respect to either δ18O or δ13C is absent in chalk samples. These patterns suggest that secretion of folia requires a more specific environmental stimulus and a greater input of metabolic carbon than chalk. Chalk is apparently secreted across a greater range of environmental conditions, with less metabolic regulation. Deviation from optimal environmental conditions, for example during periods of reduced salinity and/or cold or warm temperatures, may reduce metabolism causing the oyster to deliberately default from folia to chalk secretion. In general, folia and chalk in both estuarine and marine oysters is secreted in oxygen isotope equilibrium with the ambient environment. Another aspect of the oyster biomineral system is their ability to adhere tightly, and usually permanently, to a range of hard substrates by cementation of the left valve. Investigation of the contact zone between oyster shells and biological (other oyster shells) and inorganic (rock) substrates reveals the influence of both biogenic and non-biogenic processes in oyster cementation. Original adhesion is brought about by secretion of an organic adhesive which acts as a nucleating surface onto which crystals precipitate which have random orientation and are composed of high Mg calcite. The lack of orientation and elevated Mg content suggests that these crystals are nucleating outwith the biological control experienced by the shell biomineralisation process and are formed from inorganic precipitation from seawater. It is proposed that oysters do not control, or secrete, the crystalline cement but instead they secrete an organic film onto which crystals precipitate from seawater. Oysters thus provide excellent examples of both biologically induced and biologically controlled mineralisation

L'efficacité de l'instruction hybride dans l'apprentissage d'une langue seconde un bref résumé /

Titre de l'écran-titre (visionné le 22 oct. 2007)iÉgalement disponible en format papie

The effectiveness of blended course instruction in second language learning final report, projet #PA2004-016 /

Titre de l'écran-titre (visionné le 27 sept. 2007)Également disponible en format papierBibliogr

The effectiveness of blended course instruction in second language learning final report, projet #PA2004-016 /

Titre de l'écran-titre (visionné le 27 sept. 2007)Également disponible en format papierBibliogr

The effectiveness of blended course instruction in second language learning a brief summary /

Titre de l'écran-titre (visionné le 22 oct. 2007)Également disponible en format papie

Investigating the Integration of Student Learning Resources in Preparation for the NCLEX-RN: Phase One of a Canadian Two-Phase Multi-Site Study

Evidence-informed education practices are critical in determining effective student preparatory learning resources for the NCLEX-RN examination. Standardized testing in nursing education programs has been demonstrated to increase students NCLEX-RN success. A widely researched assessment tool for predicting NCLEX-RN examination outcomes is the HESITM RN Exit Exams. The HESI Exit Exam (E2) was determined to be between 93.36% and 99.16% accurate in predicting NCLEX-RN success (N = 49,115) with samples derived from various nursing programs throughout the United States. Purpose: This two-phase, multi-site ex-post facto study was to investigate NCLEX-RN Student Preparatory Learning Resources within the Canadian context. Phase One, which is reported here, was to determine if there was a relationship between student HESITM RN Exit and Computer Adaptive Testing (CAT) Exam scores, student grade point average (GPA), and the time lag between graduation and writing the National Licensure exam, and student outcome on the NCLEX-RN exam. Procedure: New nursing graduates were emailed study information and asked to provide their consent for the use of their student data (GPA, HESITM Exit and CAT Exam scores) for research purposes and to request that they self-report (via a password protected secure email address created for this study) their NCLEX-RN Licensure exam date and result (pass/fail) of their first exam writing. Results: Among a convenience sample of 117 new nursing alumni (graduates of 2015) from three universities in Nova Scotia, we found statistically significant mean differences in HESITM RN Exit Exam Version 1, Version 2, and CAT scores among those students that were successful on the NCLEX-RN exam versus those students that were not successful on their first writing of the NCLEX-RN exam. There was an inverse statistically significant relationship between time lag and NCLEX-RN outcome indicating that the longer the time period from graduation to writing, the less likely that the student will be successful. We found no relationship between student GPA and NCLEX-RN outcome. Discussion: Phase One results of this study suggest that there are differences in HESITM RN Exit exam and CAT scores among those students who were successful on the first write of NCLEX-RN exam versus those students who were not successful.. Although HESITM exams are just one type of the many available nursing resources to assist students to prepare for writing the National Licensure examination, our findings are significant and warrant Canadian nurse educators’ attention. Résumé Les pratiques de formation fondées sur des résultats probants sont essentielles pour déterminer l’efficacité des ressources d’apprentissage préparatoires à l’examen NCLEX-RN offertes aux étudiantes. Il a été démontré que l’utilisation d’examens standardisés dans les programmes de formation en sciences infirmières augmente le taux de réussite des étudiants à l’examen NCLEX-RN. Un outil d’évaluation qui a été largement étudié et qui permet de prédire les résultats d’examen au NCLEX-RN est l’examen final HESIMD RN. Il a été déterminé que l’examen final HESI (E2) prédisait avec une précision se situant entre 93,36 % et 99,16 % le taux de réussite à l’examen NCLEX-RN (N = 49 115) dans des échantillons provenant de différents programmes de sciences infirmières aux États-Unis. Objectif : Cette étude multi-sites, en deux phases, réalisée a posteriori visait à examiner les ressources d’apprentissage préparatoires au NCLEX-RN offertes aux étudiantes dans le contexte canadien. La première phase, dont il est question dans cet article, était conçue pour déterminer s’il existait une relation entre les résultats d’examens finaux au HESIMD RN, les résultats au test adaptatif informatisé (TAI), la moyenne générale (MG) des étudiants, l’intervalle de temps entre l’obtention du diplôme et le passage de l’examen national d’autorisation à exercer, et les résultats à l’examen NCLEX-RN. Procédure : Les nouvelles diplômées en sciences infirmières recevaient un courriel fournissant des informations sur l’étude et sollicitant leur consentement pour l’utilisation de données de leur dossier d’étudiante (leur MG, leur résultat à l’examen final HESIMD et leur résultat au TAI) à des fins de recherche. Ce message leur demandait également de déclarer (par l’entremise d’une adresse courriel sécurisée protégée par mot de passe et créée pour l’étude) la date et le résultat (réussite/échec) de leur premier examen d’autorisation à exercer NCLEX-RN. Résultats : Dans l’échantillon de convenance de 117 nouvelles diplômées en sciences infirmières (diplômées de 2015) de trois universités en Nouvelle-Écosse, nous avons découvert des différences de moyennes statistiquement significatives entre les étudiantes qui ont réussi à l’examen NCLEX-RN et celles qui ne l’ont pas réussi à la première tentative, pour leurs résultats à l’examen final HESIMD RN, version 1 et version 2, et les résultats du TAI. . Une relation inverse statistiquement significative fut remarquée entre l’intervalle de temps avant de passer l’examen NCLEX-RN et le résultat à ’cet examen, ce qui indique que plus la période est longue entre l’obtention du diplôme et le passage de l’examen, moins il est probable que l’étudiante réussisse l’examen. Nous n’avons trouvé aucune relation entre la MG de l’étudiante et le résultat au NCLEX-RN. Discussion : Les résultats de la première phase de cette étude indiquent qu’il existe des différences quant aux résultats à l’examen final HESIMD RN et au TAI entre les étudiantes qui ont réussi l’examen NCLEX-RN la première fois et celles qui l’ont échoué. Bien que les examens HESIMD ne soient qu’un type de ressources parmi de nombreuses autres ressources disponibles en sciences infirmières pour aider les étudiantes à se préparer à l’examen national d’autorisation à exercer, nos résultats sont significatifs et méritent l’attention des infirmières formatrices canadiennes

Investigations into the Pilot Scale Separation of Protein and Starch Biopolymers from Oat Cereal

Cereals contain naturally occurring biopolymers (for example proteins and starches) that can be used as renewable raw materials in a variety of speciality chemical applications. The separation of protein and starch biopolymers from wheat is well established and relies on a group of proteins called glutens that have a unique network-forming functionality. Oat and other cereals do not naturally contain these gluten proteins and typically rely on chemical-based separation techniques which alter the chemical and physical structures and damage the inherent natural functionality of the biopolymers. This research study investigated the separation of the protein and starch fractions from cereals using the Al-Hakkak Process, a new aqueous process. This process involves adding water and wheat gluten protein to cereals that do not contain gluten. The wheat gluten interacts with the cereal proteins, facilitating the separation of the starch and protein fractions whilst retaining their inherent natural functionality. The aim of this research project was to investigate and optimise the pilot scale separation performance of the Al-Hakkak Process using oat flour. As very little prior research had been carried out, the focus was to characterise the oat starch and protein separation performance and gain an understanding of the mechanisms involved. A variety of techniques were employed. Large scale deformation rheology was used to gain an understanding of the oat-gluten dough rheology and establish the relationship between the rheology and the separation performance. Confocal scanning laser microscopy was used to investigate the structure of the oat-gluten protein network. The molecular interactions between the oat and gluten proteins were studied using gel electrophoresis. The network-forming functionality of the new oat-gluten protein was explored. The influence of various processing parameters on the pilot scale separation performance was investigated and the results compared with other data collected through the study to identify key processing parameters. This research programme has resulted in interesting, encouraging and some unexpected outcomes and these are discussed in detail in the thesis. It was concluded that an insoluble protein network formed in the oat-gluten dough and both kneading and extraction processes were found to contribute to the formation of this. A key conclusion was that the changes that took place in the oat-gluten dough were similar to, but not identical to, the changes that occur in wheat dough. It was proposed that the mechanism for the development of a protein network in oat-gluten dough differed from wheat dough for two main reasons: a) the presence of the oat flour disrupted the normal wheat gluten behaviour, and b) components in the oat flour altered the activity of the gluten proteins. The research identified key processing parameters for the Al-Hakkak Process including kneading time, gluten content, and sodium chloride content of the oat-gluten dough as well as sodium chloride concentration, pH, and temperature of the extract liquor. An important discovery was that the oat and gluten proteins interacted at a molecular level through reducible, covalent, bonding (most likely disulphide linkages) to form the insoluble protein network in the oat-gluten dough. It was concluded that these reducible bonds coupled the individual protein subunits to form new hybrid oat-gluten protein molecules (a combination of oat proteins and gluten proteins). Both insoluble and soluble proteins in the oat and gluten flour were involved in the formation of the insoluble protein network in the oat-gluten dough. This outcome has applications beyond the Al-Hakkak Process, as this new knowledge can be applied to the wider dough processing industry. It was concluded that the wheat gluten was the source of the protein network-forming functionality of the hybrid oat-gluten protein and that the oat proteins had a diluting effect. It was proposed that oat-gluten protein flour from the Al-Hakkak Process could be reused to replace the commercial wheat gluten flour in subsequent production batches. During spray drying of the starch stream, the soluble biopolymers in the extract liquor were found to act as an adhesive and glued individual starch granules together to form spherical agglomerates. Acidification of the extract liquor was found to enhance this agglomeration. It was proposed the acidified starch granules were sticker during spray drying due to the partial acid hydrolysis of the starch granule suface which enhanced the agglomeration

Damnant quodnon intelligent? Trinity Western University's School of Law

As the 21st Century progresses and Canadian society becomes more diverse, organizational challenges arise when conflicting worldviews collide. The case study Damnant Quodon Intelligent? explores Trinity Western University’s proposal to establish a School of Law and the resistance it faces, principally because of organizational policies that flow from the university’s identity as a private, Christian post-secondary institution. The case seeks to invite discussion regarding organizational / societal ethical behavior, the management of dichotomous worldviews, the balancing of competing rights, and the salience of diverse stakeholder perspectives