Host-parasite relationships in mycoparasite /

A mycoparasite, Piptocephalis virginiana ^ shows a resemblance to fungal parasites of higher plants in the fine structure of hyphae and haustoria. The morphology and fine structure of host and parasitic fungi have been described. The mode of penetration of the host cell, Choanephora cucurbitarum , probably involves mechanical forces. Although the presence of cell wall degrading enzyme was not detected by conventional techniques, its role in penetration can't be ruled out. A collar around the haustorial neck is formed as an extension of the host cell wall. No papilla was detected although appressorixim was seen during penetration. The young haustorium is enclosed in highly invaginating plasmalemma of the host cell and n\imerous cisternae of endoplasmic reticulum. Appearance of an electron—dense sheath around the mature haustorium seems to coincide with the disappearance of cisternae of endoplasmic reticulum from the host cystoplasm in the vicinity of the haustorium. The role of host cytoplasm particularly of endoplasmic reticulum in the development of the sheath is discussed. Extensive accumulation of spherosomes-like bodies, containing lipids, is found in haustorium, parasite and host hypha. Electron microscope revealed the parasiticculture spore has more lipid content than the axenic culture spore of P. virginiana . The biochemical and cytochemical tests also support these results. The mature spore of C. cucurbitarum possesses a thick three-layered cell wall, different from the hyphal wall. Its germination is accompanied by the formation of an elastic thin inner layer which surrounds the emerging germ tube and the growing hypha. High resolution autoradiography showed that H N-acetyl-glucosamine , a precursor of chitin, was incorporated preferentially in the thin inner layer of the spore wall and also in the cell wall of the growing hypha. When the label was fed to the infected cells, at different intervals after inoculation, grains were observed on the sheath which developed around the haustorium of P. virginiana , 30 hours after inoculation. The significance of these results in relation to the origin and composition of the sheath is discussed.

The impact of meaningfulness of and responsibility for work on the relationships among work values, organizational commitment, and job satisfaction for part- time faculty in a community college

One hundred and thirty four subjects participated in this survey. Quantitative data were obtained and correlational analyses were used to test a model to study the relationships among the achievement of work values and organizational commitment and job satisfaction and to identify the moderating effects of the meaningfulness of work and responsibility for work on these relationships. Part-time faculty in the Faculty of Continuing Education of a community college were mailed a questionnaire on all the variables of the model. Several reliable, valid instruments were used to test the variables. Data analysis through Pearson correlation and stepwise multiple regression analyses revealed that the achievement of the work values of recognition and satisfaction with promotions did predict organizational commitment and job satisfaction, although the moderating effects of the meaningfulness of work and responsibility for work was not supported in this study. This study suggests that the revised model may be used for determining the relationships between the achievement of work values and organizational commitment and job satisfaction in a community college setting.

The relationship between stem-form, stand-closure and site -conditions : the influence of environmental conditions on tree allometry and forest structure in west-central Alberta

Changes in the configuration of a tree stern result insignificant differences in its total volume and in the proportion of that volume that is merchantable timber. Tree allometry, as represented by stem-fo~, is the result of the vertical force of gravity and the horizontal force of wind. The effect of wind force is demonstrated in the relationship between stem-form, standclosure and site-conditions. An increase in wind force on the individual tree due to a decrease in stand density should produce a more tapered tree. The density of the stand is determined by the conditions that the trees are growing under. The ability of the tree to respond to increased wind force may also be a function of these conditions . This stem-form/stand-closure/site-conditions relationship was examined using a pre-existing database from westcentral Alberta. This database consisted of environmental, vegetation, soils and timber data covering a wide range of sites. There were 653 sample trees with 82 variables that formed the basis of the analysis. There were eight tree species consisting of Pinus contorta, Picea mariana, Picea engelmannii x glauca, Abies lasiocarpa, Larix laricina, Populus tremuloides, Betula papyrifera and Populus balsamifera plus a comprehensive all-species data set. As the actual conformation of the stern is very individual, stem-fo~was represented by the diameter at breast height to total height r~tio. The four stand-closure variables, crown closure, total basal area, total volume and total number of stems were reduced to total basal area and total number of stems utilizing a bivariate correlation matrix by species. Site-conditions were subdivided into macro, meso and micro variables and reduced in number 3 using cross-tabulations, bivariate correlation and principal components analysis as screening tools. The stem-fo~/stand-closure relationship was examined using bivariate correlation coefficients for stem-fo~ with total number of stems and stem-fo~ with total basal area. The stem-fo~/site-conditions and the stand-closure/site- conditions relationships were examined using multiple correlation coefficients. The stem-form/stand-closure/site-conditions relationship was examined using multiple correlation coefficients in separate analyses for both total number of stems and total basal area. An increase in stand-closure produced a decrease in stem-form for both total number of stems and total basal area for most species. There was a significant relationship between stem-form and site-conditions and between stand-closure and site-conditions for both total number of stems and total basal area for most species. There was a significant relationship between the stemform and site-conditions, including the stand-closure, for most species; total number of stems was involved independently of the site-conditions in the prediction of stem-form and total basal area was not. Larix laricina and Betula papyrifera were the exceptions to the trends observed with most species. The influence of both stand-closure (total number of stems in particular) and site-conditions (elevation in particular) suggest that forest management practices should include these- ecological parameters in determining appropriate restocking levels.

Exploring Chinese-Canadians' perspectives on health : a quantitative study

Chinese have unique perspectives on health and illness, which is mostly umecognized by western medicine. Immigration may contribute to problems with health consultations, inconvenience, and dissatisfaction. As the largest visible minority in Canada, Chinese- Canadians' perspectives on health should be studied in order to help Chinese immigrants adapt to a new health-care and health-promotion system, and keep them healthy. A quantitative questionnaire was designed based on the findings from a pilot study and previous literature. A hundred participants were recruited from Toronto, Vancouver, Halifax, and St. Catharines. Descriptive analysis and correlation analysis were used to investigate the structure of the variables. Findings indicated that most oftheir attitudes and corresponding practices to the different health aspects were positive. The relation between dietary practices and attitude was only found in small cities. Their attitudes were impacted by their length of stay in Canada. Their attitudes to regularly timed meals and psychological consultation were related to their acculturation level, as was the regularity of their practice of dental flossing. Their self-evaluated general health levels were also found to be affected by their medical history, education level, feeling to talk about • sexual health, and smoking, particularly in the male subjects of the study. In conclusion, they realized that each health aspect w~s important to their health. However, their practices did not bear a strong relation to their beliefs. Traditional thoughts about health reseeded with time. Acculturation level did not affect most of their attitudes or practices. Under pressure, the priority of the daily health practices decreased. Older persons, those with low incomes, lower education levels or families under stress need to pay more attention to their health level. In-depth future research was recommended.

An Exploration Into Doctoral Students' Sense of Community and its Influence on the Formation of Informal Mentoring Relationships

This exploratory mixed method research project was designed to investigate an area of doctoral education that has received little attention in the past. This research focused specifically on the non-intellectual, hoped-for by-products of doctoral education; the dynamic processes of developing and maintaining both a sense of community and informal mentoring relationships. The design of the study captured the experiences of doctoral students and alumni at various time periods in the doctoral program. Participants represented a diverse group of students with differences in professional and academic backgrounds and life stages. A pilot study for this research suggested that the presence of a sense of community and informal mentoring may provide the necessary relationships to support this diversity. The primary question at the forefront of this study was: Do doctoral students feel connected to one another? Five subquestions were developed to address this research topic: Does a sense of community already exist and flourish in doctoral education? Are the programs and resources of the doctoral program organized to nurture the creation and maintenance of a sense of community? Is a sense of community a foundational element in the formation of naturally occurring relationships among doctoral students? What educational and socio-emotional benefits are associated with informal mentoring relationships during the doctoral experience? and Do doctoral students perceive a change in their development as stewards of their discipline over time? The principal methods used to investigate these research questions combined both quantitative and qualitative techniques in a concurrent time sequence. The quantitative portion of the study involved a questionnaire, while the qualitative portion involved two approaches; face-to-face interviews and an open-ended question at the end of the questionnaire. Findings from the study indicated that the presence of both sense of community and informal mentoring enhance the overall quality of doctoral education. Program elements that enhanced or hindered connection between students were identified. Both the dynamics and the emotional, social, and academic benefits of informal mentoring were elucidated. Over time participants perceived changes in their development of the qualities assqciated with stewardship. This study brought the "hoped-for by-products" associated with doctoral education from the background shadows to an illuminated position at the forefront of inquiry.

New Building Blocks for Dual-Property Molecule-Based Magnets

Two classes of compounds have been prepared and characterized as building blocks for chiral magnets and ferromagnetic conductors. In the fIrst project, the organic framework of a pentadentate, (N302) macro cycle has been synthetically modifIed to introduce phenyl substituents into its organic framework and the synthesis of four new [Fe(In(N302)(CN)2] complexes (I) - (IV) is presented. [Molecular diagram availble in pdf] This work represents the fIrst structural and magnetic studies of a family of spin crossover macrocycles that comprise of both structural and stereo-isomers. Magnetic susceptibility and Mossbauer data for the R,R-complex (I) is consistent with both a thermal and a light induced spin crossover transition. The X-ray data supports a change in geometry accompanying the thermal spin transition, from a high spin (HS) 7 -coordinate complex at room temperature to a low spin (LS) 5-coordinate complex at 100 K. The crystal structure ofthe racemic complex (III) reveals a HS, 7-coordinate complex at 200 K that undergoes no signifIcant structural changes on cooling. In contrast, the magnetic - susceptibility and Mossbauer data collected on a powder sample of the racemic complex are consistent with a LS complex. Finally, the meso complex (IV) was prepared and its structure and magnetic properties are consistent with a 5-coordinate LS complex that remains low spin, but undergoes conformational changes on cooling in solution. The chiral [Fe(H)(N302)(CN)2] macro cycle (I), together with its Mn(H) and Fe(H) derivatives have also been exploited as building blocks for the self-assembly of chiral magnets. In the second project, a synthetic route for the preparation of tetrathiafulvalene (TTF) donors covalently attached to a diisopropyl verdazyl radical via a cross conjugated pyridyl linker IS presented. Following this strategy, four new TTF-py- (diisopropyl)verdazyl radicals have been prepared and characterized (V) - (VIII) . [Molecular diagram available in pdf] The first (2:1) charge transfer complex ofa TTF-py-(diisopropyl)verdazyl radical donor and a TCNQ acceptor has been prepared and structurally characterized. The crystal packing shows that the donor and acceptor molecules are organized in a mixed stacking arrangement consistent with its insulating behaviour. EPR and magnetic susceptibility data support intramolecular ferromagnetic interactions between the TTF and the verdazyl radicals and antiferromagnetic interactions between TTF donors within a stack. In an attempt to increase the intramolecular exchange interaction between the two radicals, a TTF-x-(diisopropyl)verdazyl radical (IX) was prepared, where the two radicals are connected ia a conjugated divinylene linker. The neutral radical donors stack in a more favourable head-to-head arrangement but the bulky isopropyl groups prevent the donor radicals from stacking close enough together to facilitate good orbital overlap. [Molecular diagram available in pdf].

Investigating the Relationships Between Teacher Identity Norms and Collaboration

The purpose of this study was to investigate how teacher identity norms relate to teacher collaboration among the practices of elementary teachers in Ontario. Using quantitative research methods, the data indicated two clusters of teacher identity norms. The norm cluster of innovation, interdependence, and cooperation showed positive correlations with collaboration and the norm cluster of conservatism, individualism, and competition showed negative correlations with collaboration. The two clusters of norms also correlated with each other. The data showed that teachers highly valued collaboration as part of their teaching practice but did not always experience it in their school setting. The analysis suggested that if schools reinforce norms of innovation, interdependence, and cooperation, collaboration will be nurtured. Further, the data showed that if norms of conservatism, individualism, and competition are continued in school cultures, then collaboration will not be sustained. As a broad educational reform agenda, teacher collaboration is used (a) to support school cultures, (b) to change teaching practices, and (c) to implement policy-based initiatives. This research is expected to benefit teachers in its capacity to inform policy makers concerning the highly complex nature of teacher collaboration and some of the factors that impact it. With an understanding of the relationships between teacher identity norms and collaboration, it may be possible for policy makers to provide appropriate support structures that reinforce collaboration in teachers' practices as well as predict potential levels of collaboration within school cultures.