Measurement of forces between and within bilayers of neutral phospholipids

Phospholipids in water form lamellar phases made up of alternating layers of water and bimolecular lipid leaflets. Three complementary methods, osmotic, mechanical, and vapour pressures, were used to measure the work of removing water from lamellar phases composed of frozen dipalmitoylphosphatidylcholine ( DPPC ), melted DPPC, egg phosphatidylethanolamine or equimolar mixtures of DPPC and cholesterol ( DPPC/CHOL ), Concurrently the structural changes that resulted from this water removal were measured using X-ray diffraction. The work was divided into that which forces the bilayers together ( F ) and that which compresses the molecules together within the bilayers ( F )# A large repulsive force exists between bilayers composed of each of the lipids studied and this force increases exponentially as bilayer separation is decreased. F is affected by the nature of the head groups, conformation of the acyl chains and heterogeneity of these chains. In general all of the melted phosphatidylcholines ( melted DPPC, egg lecithin and DPPC/CHOL ) have large equilibrium separations in excess water resulting from large repulsive hydration forces between these bilayers. By comparison, egg PE has an increased attractive force, and frozen DPPC has a decreased hydration force; each results in smaller separations in water for these two lipids. The chemical potentials of the water between the bilayers for all these lipids lie on a continuum, indicating that interbilayer water cannot be characterized by two discrete states, usually referred to as "bound" or "non**bound". For all lipids studied a maximum of 25 % of the total work done on the system goes into deforming the bilayers. The method used here viii to separate repulsion from deformation, developed for us by v. A. Parsegian, provides a unique method for the measurement of lateral pressure of a bilayer and its modulus of deformability ( Y ). Lateral pressure is affected by the nature of the head group, conformation and heterogeneity of the acyl chains. For small changes in molecular surface area ( A ) near equilibrium, both melted and frozen DPPC have similar values for the deformability modulus. Thus in this regime it requires about the same force to change the angle of tilt of frozen chains as it does to compress the fluid bilayer. The introduction of cholesterol into bilayers of DPPC reduces dramatically the lateral pressure of the bilayers over a large range of molecular surface areas ( A ). The variation in the magnitude of bilayer repulsion with different phospholipids provides a basis for the mechanism of lipid segregation in mixed lipid systems and suggests that interacting heterogeneous membranes may influence or modulate the composition of the opposing membrane. The measurements of deformabilities of bilayers provides a direct comparison of them with the properties of monolayers.

Measurement of repulsive forces between charged phospholipid bilayers

Electrostatic forces between membranes containing charged lipids were assumed to play an important role in influencing interactions between membranes long before quantitative measurements of such forces were available. ~ur measurements were designed to measure electrostatic forces between layers of lecithin charged with lipi~s carrying ionizable head groups. These experiments have shown that the interactions between charged lipid bila.yere are dominated by electrostatic forces only at separations greater than 30 A. At smaller separations the repulsion between charged bilayers is dominated by strong hydration forces. The net repulsive force between egg lecithin bilayers containing various amounts of cherged lipids (phosphatidylglycerol (PG) 5,10 ano 50 mole%, phosphatidyli. nosi tol (PI) 10 mole% and sodium oleate (Na-Ol) 3,5 and 10 mole%, where mole% gives the ratio of the number of moles' of .charged lipid to the total number of moles of all lipids present in the sample) was stuoied with the help ('If the osmotic streas technique described by LeNeveu et aI, (1977). Also, the forces between pure PG were j_nvestigated in the same manner. The results have been plotted showing variation of force as a function of bilay- _ er separation dw• All curVes 90 obtained called force curves, were found to be similar in sha.pe, showing two distinct regions, one when dw<.30 A is a region cf very rapid iiivariation of force with separation ( it is the region dominated by hydre,tion force) and second when dw> 40 A is a region of very slow variation of force with separB.tion ( it is the region dominated by the electrostatic force). Between these two regions there exists a transition area in which, in most systems studied, a phase separation of lipids into fractions containing different amounts of charged groups, was observed. A qualitative analysis showed that our results were v/ell described by the simple electrostatic double -le.yer theory. For quantitative agreement between measured and calculated force curves however, the charge density for the calculations had to be taken as half of that given by the number density of charged lipids present in the lecithin bilayers. It is not clear at the moment what causes such low apparent degree of ionization among the charged head groups, and further study is needed in this area.

Non-invasive measurement of trigeminal nerve somatosensory evoked potentials

Whiplash injuries are common yet enigmatic to substantiate clinically. Trigeminal somatosensory evoked potentials (TSEPs) were posited as an indicator of trigeminal nerve conduction damage resulting from whiplash. Alternating polarity square-wave current stimuli were applied transcutaneously in the facial region. 379 recorded pilot trials from 27 participants (8 male and 19 female) were utilized to develop a non-invasive recording capability for TSEPs. Stimulus intensity and artifact, cortical recording sites, stimulation electrode design and placement were explored. Statistically significant differences in amplitude of TSEP waveform components at 13, 19 and 27 ms between uninjured and whiplashed participants were noted. Increased stimulus intensity in whiplashed participants was observed to increase TSEP amplitude. The present methodology and hardware are discussed and directions for future advancement of the current process are outlined.

Self-directedness, personality type and success in self- employment

The new economy has spirited a transformation ofwork organizations from big business structures into smaller, more flexible enterprises, many of which are launched as self-employment initiatives. The growing trend towards increasing selfemployment in Canada demands aeritical review of how educational programs support and encourage entrepreneurship and self-employment opportunities for students ofpost-secondary and adult training programs. The focus ofthis study was threefold. First, the study examined whether a relationship exists between self-directedness and success in self-employment. Secondly, the purpose of this research was to determine whether a relationship exists between psychological type as defined by Jung and success in selfemployment. Finally, this research effort attempted to develop a model for identifying individual potential for self-employment based on combined factors of self-directedness and psychological type. Success was measured in three stages: 1) Did the subject start a selfemployment initiative? 2) Did the business survive six months? 3) Did the business survive one year? The research went beyond classroom training activities to determine whether individuals actually started a business enterprise while participating ina self-employment program designed for individuals who were unemployed. Given that many people initiate a self-employment venture.without actually operating the business beyond the initial start-up, this research effort measured success based on a commitment of at least one year to the selfemployment initiative. Results ofthe study revealed that individuals with a high level of selfdirected learning readiness tended to be more likely to succeed in business in terms ofbusiness starts, survival for six months, and survival for one year. In addition, it was discovered that individuals who were extraverted intuitive types succeeded more often in business at all three levels than any other type. These findings supported a model using the SDLRS and the PET Type Check as predictors for success in entrepreneurial ventures.

The measurement of the optical absorption cross section of photosystem 1 and photosystem 2 from whole live cells of porphyridium cruentum, in light state 1 and light state 2

The optical cross section of PS I in whole cells of Porphyridium cruentum (UTEX 161), held in either state 1 or state 2, was determined by measuring the change in absorbance at 820nm, an indication of P700+; the X-section of PS2 was determined by measuring the variable fluorescence, (Fv-Fo)/Fo, from PS2. Both cross-sections were 7 determined by fitting Poisson distribution equations to the light saturation curves obtained with single turnover laser flashes which varied in intensity from zero to a level where maximum yield occurred. Flash wavelengths of 574nm, 626nm, and 668nm were used, energy absorbed by PBS, by PBS and chla, and by chla respectively. There were two populations of both PSi and PS2. A fraction of PSi is associated with PBS, and a fraction of PS2 is free from PBS. On the transition S1->S2, only with PBS-absorbed energy (574nm) did the average X-section of PSi increase (27%), and that of PS2 decrease (40%). The fraction of PSi associated with PBS decreased, from 0.65 to 0.35, and the Xsection of this associated PS 1 increased, from 135±65 A2 to 400±300A2. The cross section of PS2 associated with PBS decreased from 150±50 A2 to 85±45 A2, but the fraction of PS2 associated with PBS, approximately 0.75, did not change significantly. The increase in PSi cross section could not be completely accounted for by postulating that several PSi are associated with a single PBS and that in the transition to state2, fewer PSi share the same number of PBS, resulting in a larger X-section. It is postulated that small changes occur in the attachment of PS2 to PBS causing energy to be diverted to the attached PSi. These experiments support neither the mobile-PBS model of state transitions nor that of spillover. From cross section changes there was no evidence of energy transfer from PS2 to PSi with 668nm light. The decrease in PS2 fluorescence which occurred at this wavelength cannot be explained by energy transfer; another explanation must be sought. No explanation was found for an observed decrease in PSi yield at high flash intensities.

Delineation of within-site terroir effects using soil and vine water measurement. Investigation of Cabernet Franc

. The influence of vine water status was studied in commercial vineyard blocks of Vilis vinifera L. cv. Cabernet Franc in Niagara Peninsula, Ontario from 2005 to 2007. Vine performance, fruit composition and vine size of non-irrigated grapevines were compared within ten vineyard blocks containing different soil and vine water status. Results showed that within each vineyard block water status zones could be identified on GIS-generated maps using leaf water potential and soil moisture measurements. Some yield and fruit composition variables correlated with the intensity of vine water status. Chemical and descriptive sensory analysis was performed on nine (2005) and eight (2006) pairs of experimental wines to illustrate differences between wines made from high and low water status winegrapes at each vineyard block. Twelve trained judges evaluated six aroma and flavor (red fruit, black cherry, black current, black pepper, bell pepper, and green bean), thr~e mouthfeel (astringency, bitterness and acidity) sensory attributes as well as color intensity. Each pair of high and low water status wine was compared using t-test. In 2005, low water status (L WS) wines from Buis, Harbour Estate, Henry of Pelham (HOP), and Vieni had higher color intensity; those form Chateau des Charmes (CDC) had high black cherry flavor; those at RiefEstates were high in red fruit flavor and at those from George site was high in red fruit aroma. In 2006, low water status (L WS) wines from George, Cave Spring and Morrison sites were high in color intensity. L WS wines from CDC, George and Morrison were more intense in black cherry aroma; LWS wines from Hernder site were high in red fruit aroma and flavor. No significant differences were found from one year to the next between the wines produced from the same vineyard, indicating that the attributes of these wines were maintained almost constant despite markedly different conditions in 2005 and 2006 vintages. Partial ii Least Square (PLS) analysis showed that leaf \}' was associated with red fruit aroma and flavor, berry and wine color intensity, total phenols, Brix and anthocyanins while soil moisture was explained with acidity, green bean aroma and flavor as well as bell pepper aroma and flavor. In another study chemical and descriptive sensory analysis was conducted on nine (2005) and eight (2006) medium water status (MWS) experimental wines to illustrate differences that might support the sub-appellation system in Niagara. The judges evaluated the same aroma, flavor, and mouthfeel sensory attributes as well as color intensity. Data were analyzed using analysis of variance (ANOVA), principal component analysis (PCA) and discriminate analysis (DA). ANOV A of sensory data showed regional differences for all sensory attributes. In 2005, wines from CDC, HOP, and Hemder sites showed highest. r ed fruit aroma and flavor. Lakeshore and Niagara River sites (Harbour, Reif, George, and Buis) wines showed higher bell pepper and green bean aroma and flavor due to proximity to the large bodies of water and less heat unit accumulation. In 2006, all sensory attributes except black pepper aroma were different. PCA revealed that wines from HOP and CDC sites were higher in red fruit, black currant and black cherry aroma and flavor as well as black pepper flavor, while wines from Hemder, Morrison and George sites were high in green bean aroma and flavor. ANOV A of chemical data in 2005 indicated that hue, color intensity, and titratable acidity (TA) were different across the sites, while in 2006, hue, color intensity and ethanol were different across the sites. These data indicate that there is the likelihood of substantial chemical and sensory differences between clusters of sub-appellations within the Niagara Peninsula iii

Leadership and its impact on the success of Social Sciences and Humanities Research Council funded collaborative research projects

This dissertation investigates the practice of leadership in collaboratively designed and funded research in a university setting. More specifically, this research explores the meaning of leadership as experienced by researchers who were, or still are, engaged on Social Sciences and Humanities Research Council (SSHRC) funded collaborative research projects in a university setting. This qualitative study (Gay & Airasian, 2003) is situated within a social constructivist paradigm (Kezar, Carducci, & Contreras-McGavin, 2006) and involves an analysis of the responses from 12 researchers who answered 11questions related to my overarching research question: What is the impact of leadership on university based collaborative research projects funded by the Social Sciences and Humanities Research Council based on the experiences of researchers involved? The data that emerged supported and enhanced the existing literature related to leadership and collaborative groups in academia. The type of preferred leadership that emerged as a result of this research seemed to indicate that the type of leader that appeared to be optimal in this context might be described as a functional collaborative expert.

Aboriginal women in education : Honouring our experiences a vision of access to and success within the university

This thesis explores Aboriginal women's access to and success within universities through an examination of Aboriginal women's educational narratives, along with input from key service providers from both the Aboriginal and non-Aboriginal community. Implemented through the Wildfire Research Method, participants engaged in a consensusbased vision of accessible education that honours the spiritual, emotional, intellectual, and physical elements necessary for the success of Aboriginal women in university. This study positions Aboriginal women as agents of social change by allowing them to define their own needs and offer viable solutions to those needs. Further, it connects service providers from the many disconnected sectors that implicate Aboriginal women's education access. The realities of Aboriginal women are contextualized through historical, sociocultural, and political analyses, revealing the need for a decolonizing educational approach. This fosters a shift away from a deficit model toward a cultural and linguistic assets based approach that emphasizes the need for strong cultural identity formation. Participants revealed academic, cultural, and linguistic barriers and offered clear educational specifications for responsive and culturally relevant programming that will assist Aboriginal women in developing and maintaining strong cultural identities. Findings reveal the need for curriculum that focuses on decolonizing and reclaiming Aboriginal women's identities, and program outcomes that encourage balance between two worldviews-traditional and academic-through the application of cultural traditions to modern contexts, along with programming that responds to the immediate needs of Aboriginal women such as childcare, housing, and funding, and provide an opportunity for universities and educators to engage in responsive and culturally grounded educational approaches.

Measurement of growth in the lichen Rhizocarpon geographicum using a new photographic technique

Lichenologists and users of lichenometry have long used calipers or photogrammetry to measure the growth of crustose lichens. Now, digital photography and popular computer software provide methodological alternatives. This thesis developed and tested a new methodology for tracking change and growth of the lichen, Rhizocarpon geographicum. Adobe Photoshop CS3 Extended software and a photographic time series (1996,2003,2006 and 2007) were used to measure thallus diameter, area, prothallus width and areolae area in 115 small R. geographicum thalli (0.53-1049.88 mm2 ). Measures of 8 diameters per thallus showed that change in diameter was highly variable and is a weak index of growth. Thallus area was a reliable measure of growth (power correlation, R2 = 0.89). Rapid, highly irregular growth occurred in small thalli «30 mm2 ), and steady, uniform growth occurred in larger thalli (>30 mm2 ). This new methodology is tedious but can potentially generate accurate and precise measures for even the tiniest of lichens.

Creating a Space for Self-Transformation: Factors of Success for Adult Literacy Learners with Specific Learning Difficulties

A significant number of adults in adult literacy programs in Ontario have specific learning difficulties. This study sought to examine the holistic factors that contributed to these learners achieving their goals. Through a case study design, the data revealed that a combination of specific learning methods and strategies, along with particular characteristics of the instructor, participant, and class, and the evidence of self-transformation all seemed to contribute to the participant's success in the program. Instructor-directed teaching and cooperative learning were the main learning methods used in the class. General learning strategies employed were the use of core curriculum and authentic documents, and using phonics, repetition, assistive resources, and using activities that appealed to various learning styles. The instructor had a history of both professional development in the area of learning disabilities as well as experience working with learners who had specific learning difficulties. There also seemed to be a goodness of fit between the participant and the instructor. Several characteristics of the participant seemed to aid in his success: his positive self-esteem, self-advocacy skills, self-determination, self-awareness, and the fact that he enjoyed learning. The size (3-5 people) and type of class (small group) also seemed to have an impact. Finally, evidence that the participant went through a self-transformation seemed to contribute to a positive learner identity. These results have implications for practice, theory, and further research in adult education.

How Learning Styles, Chemistry Attitudes and Experiences, Confidence, and Demographics Correlate with Academic Success in First and Second Year Chemistry Courses

At Brock University, the Faculty of Mathematics and Science currently has one of the highest percentages of students on academic probation, with many students reporting the most difficulty with Introductory Chemistry in first year and Organic Chemistry in second year. To identify strategies to improve students' performance and reduce the number of students on academic probation, a multi-year research project was undertaken involving several chemistry courses. Students were asked to complete three questionnaires, and provide consent to obtain their final Chemistry grade from the Registrar's Office. Research began at the end of the 2007-08 academic year with CHEM IPOO, and in the 2008-09 academic year, students in the larger CHEM IF92 Introductory Chemistry course were invited to participate in this research near the beginning of the academic year. Students who went on to take second year Organic and Analytical Chemistry were asked to complete these questionnaires in each second year course. The three questionnaires included the Kolb Learning Styles Inventory (Kolb, 1984) modified to include specific reference to Chemistry in each question, Dalgety, ColI, and Jones' (2002) Chemistry Attitudes and Experiences Questionnaire (CAEQ), and lastly, a demographic survey. Correlations were found between learning style and academic success; concrete learners were not as successful as abstract learners. Differences were noted between females and males with respect to learning styles, academic success, and confidence. Several differences were also noted between those who are the First in the Family to attend university and those who are not First in the Family to attend university.

VOCATIONAL INTERESTS: CONSTRUCT VALIDITY AND MEASUREMENT

This dissertation addressed several questions relevant to vocational interests and personality characteristics, examining (a) the roles of personality, vocational interests, and sexual fantasies in defining a general factor of Masculinity/Femininity (M/F) (Study 1), (b) the validity of a new measure of vocational interests (Study 2), and (c) the individual difference characteristics that discriminate between students in various academic majors, and that predict academic outcomes (Study 3). In Study 1, vocational interests, personality, and sexual fantasies were examined to find whether these variables would yield a general Masculinity/Femininity (M/F) factor, and whether that factor would still emerge when controlling for participant sex. The results of Study 1 revealed that a general factor of M/F did emerge. When sex was removed, the loadings of vocational interests decreased from high to very low, suggesting that the link of vocational interests with other indicators of M/F is mainly due to sex differences in these variables. The purpose of Study 2 was to validate the Oregon Vocational Interest Scales (ORVIS), a new public domain vocational interests questionnaire designed to measure eight vocational interest scales. ORVIS scores obtained in a college and community sample were compared with those of two personality measures and two cognitive ability tests. Results from this study showed that the ORVIS scales were reliable and showed good construct validity. The purpose of Study 3, using the ORVIS along with the HEXACO-PI and tests of cognitive ability, was to examine the individual difference characteristics of students in different academic majors, and to use the congruence between a student's academic major and vocational interests as a predictor of academic outcomes, such as GPA, academic major change, and satisfaction with major. The results of Study 3 revealed that students in different academic majors show theoretically meaningful differences in personality, abilities, and interests. Conscientiousness and math ability were found to be the best predictors of academic outcomes. However, congruence between major and interests did not add significant predictive validity to any of these outcomes beyond personality and ability. Together, these three studies show the role of vocational interests in defming MlF and in predicting various academic outcomes.

Aboriginal Parental Involvement/Engagement for Student Success

An increasing body of knowledge links parental involvement with student success but few studies address Aboriginal parental involvement in urban settings. While some critics argue traditional Aboriginal knowledge is best delivered at home, Aboriginal children who share parents’ stories in the classroom benefit other children who draw connections to these stories. Moreover, Aboriginal learners need to function in mainstream Western society and in public school settings in which educators often have a difficult time engaging Aboriginal parents. Consequently, this research sought to explore the perceptions and sense of engagement of parents/caregivers in the Aboriginal Student Program (ASP) in a publicly funded secondary school in Ontario. The study was an extension of the researcher’s existing work and focused specifically on a sample of parents/caregivers taking part in an Aboriginal feast at an Ontario secondary school. Nine individuals accepted an invitation to participate in a Talking Circle and shared perceptions of their children’s educational experiences. Data were collected and coded, and findings indicated that parental involvement in children’s educational journeys contributed significantly to a sense of parental engagement in the school and in Aboriginal programs. Results also suggest that Eurocentric pedagogy can be modified in mainstream secondary schools to directly involve Aboriginal parents/caregivers. Although many participants’ stories revealed they experienced racism during their own schooling, study findings demonstrate that the parents/caregivers want to be involved in their children’s education nonetheless. This thesis discusses the data that were grounded in the participants’ voices that in turn led to several key recommendations.

A Qualitative Study of the Professional Experiences of Teachers With Mobility Challenges and Their Self-Perceptions of Professional Success

This qualitative investigation explored the professional experiences of 3 Ontario teachers who have mobility challenges. The study’s participants (2 male and 1 female) were Ontario teachers who have permanent physical disabilities that challenge their means of mobility. Each participant has an Ontario Certified Teaching License and has either taught or is currently teaching in an Ontario school. My primary source of data collection was a semi-structured face-to-face interview with each participant. The focus of the interview was participant perspectives. Data analysis was accomplished in 3 phases. Data analysis generated 5 prominent themes of commonality among participants: (a) independence and sacrifice, (b) living with pain, (c) barriers and obstacles, (d) the importance of communication, and (e) professional benefits and personal rewards.

Statement of finals of the marsh lands main drain as near as can be estimated until its completion and final measurement

Statement of finals of the marsh lands main drain as near as can be estimated until its completion and final measurement. This is signed by Fred Holmes, July 9, 1857.