Electrophysiological correlates of performance monitoring in middle and late adolescence

The ability to monitor and evaluate the consequences of ongoing behaviors and coordinate behavioral adjustments seems to rely on networks including the anterior cingulate cortex (ACC) and phasic changes in dopamine activity. Activity (and presumably functional maturation) of the ACC may be indirectly measured using the error-related negativity (ERN), an event-related potential (ERP) component that is hypothesized to reflect activity of the automatic response monitoring system. To date, no studies have examined the measurement reliability of the ERN as a trait-like measure of response monitoring, its development in mid- and late- adolescence as well as its relation to risk-taking and empathic ability, two traits linked to dopaminergic and ACC activity. Utilizing a large sample of 15- and 18-year-old males, the present study examined the test-retest reliability of the ERN, age-related changes in the ERN and other components of the ERP associated with error monitoring (the Pe and CRN), and the relations of the error-related ERP components to personality traits of risk propensity and empathy. Results indicated good test-retest reliability of the ERN providing important validation of the ERN as a stable and possibly trait-like electrophysiological correlate of performance monitoring. Ofthe three components, only the ERN was of greater amplitude for the older adolescents suggesting that its ACC network is functionally late to mature, due to either structural or neurochemical changes with age. Finally, the ERN was smaller for those with high risk propensity and low empathy, while other components associated with error monitoring were not, which suggests that poor ACe function may be associated with the desire to engage in risky behaviors and the ERN may be influenced by the extent of individuals' concern with the outcome of events.

Genesis and distribution of Mississippi Valley-type ore assemblages in Middle Silurian strata, Niagara Peninsula, Ontario /

Presently non-commercial occurrences of Mississippi Valley-type ore assemblages in the Middle Silurian strata of the Niagara Peninsula have been studied. Based on this detailed study, a new poly-stage genetic model is proposed which relates ore mineralization in carbonate environments to the evolution of the sedimentary basin. Sulphide ore mineralization occurred during two episodes: 1. During the late diagenesis stage, which is characterized by compaction-maturation of the sediments, the initial mineralization took place by upward and outward movement of connate waters. Metals were probably supplied from all the sediments regardless of their specific lithologies. However, clay minerals were possibly the main contributors. The possible source of sulphur was from petroleum-type hydrocarbons presently mixed with the sediments at the site of ore deposition. Evidence for this is the fact that the greatest abundance of ore minerals is in petroliferous carbonates. The hydrocarbons probably represent liquids remaining after upward migration to the overlying Guelph-Salina reservoirs. The majority of sphalerite and galena formed during this period, as well as accessory pyrite, marcasite, chalcopyrite, chalcocite, arsenopyrite, and pyrrhotite; and secondary dolomite, calcite, celestite, and gypsum. 2. During the presently ongoing surface erosion and weathering phase, which is marked by the downward movement of groundwater, preexisting sulphides were probably remobilized, and trace amounts of lead and zinc were leached from the host material, by groundwaters. Metal sulphides precipitated at, or below, the water table, or where atmospheric oxygen could raise the Eh of groundwaters to the point where soluble metal complexes are unstable and native sulphur co-precipitates with sphalerite and galena. This process, which can be observed today, also results in the transport and deposition of the host rock material. Breakdown of pre-existing sulphide and sulphate, as well as hydrocarbon present in the host rock, provided sulphur necessary for sulphide precipitation. The galena and sphalerite are accompanied by dolomite, calcite, gypsum, anglesite, native sulphur and possibly zincite.

Teacher attitudes and the emotionally-behaviourally disordered middle school student

Inclusionary practlces prescrlbe that children, regardless of exceptlonal1ty shall benefit from recelving educatlonal servlce 1n the context of the regular class setting. The resulting el1mlnatlon of separate speclal classes could be v1ewed as aneconom1c advantage. In po1nt of fact, many school boards and d1strlcts 1n both Canada and the Unlted States are movlng towards 1mplementatlon of lncluslonary practice, posslbly for the above stated reason. Regardless, 1ncluslon as It relates to the emot1onal1y/behav1ourally disordered youth in our school systems may not be successful. Regular education teachers may not be prepared professlonal1y or personally to deal wlth this very spec1al student populat1on. Th1s study focused on teacher attitude 1n thls regard. As welll poss1ble factors that may lead to successful 1nclusion of these students are examined. Of these, teacher exper1ence, educat10n spec1f1c to the d1sab111ty of emot1onal/behavloural dlsordered comb1ned w1th teacher self-percept1on of success appear to hold the greatest promise. In v1ew of these flndlngs, recommendations are made for professlonal pract1ce and future research d1rect1ons.

Canada/U.S. border crossing: facilitation and constraint

Abstract The aim of this research project is to draw on accounts of experiences ofborder crossing and regulation at the Canada/U.S. border at Niagara in order to illuminate the dynamics of differentiation and inequality at this site. The research is informed by claims that the world is turning into a global village due to transnational flows oftechnology, infonnation, capital and people. Much of the available literature on globalization shows that while the transfer of technology, information, and capital are enhanced, the transnational movement of people is both facilitated and constrained in complex and unequal ways. In this project, the workings of facilitation and constraint were explored through an analysis often interviews with people who had spent a substantial portion oftheir childhood (e.g. 5 years) in a Canadian border community. The interviewees were at the time ofthe research between the ages of 19 and 25. Because most ofthe respondents were 'white' Canadians of working to upper middle class status, my focus was to explore how 'whiteness' as privilege may translate into enhanced movement across borders and how 'white' people may internalize and enjoy this privilege but may often deny its reality. I was also interested in how inequality is perceived, understood, and legitimated by these relatively privileged people. My analysis ofthe ten accounts ofborder crossing and regulation suggests that differentially situated people experience border crossing differently. An important finding is that while relatively privileged border crossers perceived and often problernatized differential treatment based on external factors such as physical appearance, and especially race, most did not challenge such treatment but rather saw it as acceptable. These findings are located within newer literature that addresses the increasing securitization ofborders and migration in western societies.

Microstructural and geochemical investigation of North American lower-middle Paleozoic trilobites and recent arthropods

Trilobites ¥tere collected from Ordovician and Devonian formations of Ontario} New York} Ohio} Oklahoma} and Indiana. Diversity was generally low} but 19..?telllS and Ph..~tY>ps ¥tere the most abundant species from the Ordovician and Devonian} respectively. Recent marine arthropods ¥tere collected from the Atlantic shore of the middle Florida Keys} and from the Pacific and lagoonal waters at Cape Beale} B. C. Fresh-water arthropods were collected along the shore of the Severn River in northcentral Ontario. Cuticles ¥tere analyzed for major} minor and trace elements, 180 and 13C isotopes, as ¥tell as examined by scanning electron micr?scope to identify original and diagenetic fabrics. Examination of trilobite cuticles by scanning electron microscope revealed several microstructures consistent with those observed in Recent arthropods. Microstructures} such as setae and tegumental gland duct openings} in like sized Lim/IllS and Isoteline trilobites may indicate common ancestral origins for these organisms, or simply parallel cuticle evolutions. The dendritic microstructure, originally' thought to be a diagenetic indicator, was found in Recent specimens and therefore its presence in trilobites may be suggestive of the delicate nature of diagenesis in trilobites. The absence of other primary microstructures in trilobites may indicate alteration, taxonomic control} or that there is some inherent feature of S EM examination which may' not allow detection of some features} while others are apparently visit·le onl~1 under SH.·1. The region of the cuticle sampled for examination is also a major influence in detecting pristine microstructures, as not all areas of trilobite and Recent arthropod cuticles will have microstructures identifiable in a SEM study. Subtleties in the process of alteration, however} ma~·· leave pristine microstructures in cuticles that are partial~/ silicified or do 10m itized, and degree and type of alteration may vary stratigraphically and longitudinally within a unit. The presence of fused matrices, angular calcite rhombs, and pyrite in the cuticle are thought to be indicative of altered cuticles, although pyritization may not affect the entire cuticle. t-~atural processes in Recent arthropods, such as molting, lead to variations in cuticle chemistries, and are thought to reflect the area of concentration of the elements during calcification. The level of sodium in Recent arthropods was found to be higher than that in trilobites, but highly mobile when sUbjected to the actions of VY'€'athering. Less saline water produced lovy'€'r magnesium and higher calcium values in Recent specimens .. and metal variations in pristine Ordovician trilobite cuticle appears to follow the constraints outlined for Recent arthropods, of regulation due to the chemislry of the surrounding medium. In diagenetic analysis, sodium, strontium and magnesium proved most beneficial in separating altered from least altered trilobites. Using this criterion, specimens from shale show the least amount of geochemical alteration, and have an original mineralogy of 1.7 - 2.4 mole % MgC03 (8000 t(> 9500 ppm magnesium) for both /s>..?/e/11S lJA'i.riff!11S and PseIAit'11J17ites I..itmirpin..itl/~ and 2.8 - 3.3 mole % MgC03 (5000 to 7000 ppm magnesium) for Ph.i{).?PS This is Slightly lower than the mineralogy of Recent marine arthropods (4.43 - 12.1 mole % MgC03), and slightly higher than that of fresh-water crayfish (0.96 - 1.82 mole % MgC03). Geochemically pristine trilobites were also found to possess primary microstructures. Stable isotope values and trends support the assertion that marine-meteoriclburial fluids were responsible for the alteration observed in a number of the trilobite specimens. The results of this stUdy suggest that fossil material has to be evaluated separately along taxonomic and lithological lines to arrive at sensible diagenetic and e nvironmenta I interpretations.

Middle Ordovician (Whiterockian-Chazyan) trilobites from the Sunblood Formation, District of Mackenzie

The Middle Ordovician Sunblood Formation in the South Nahanni River area, District of Mackenzie, comprises mainly limestones and dolostones of intertidal and shallow subtidal origin as indicated by the presence of desiccation polygons, fenestral fabric, and oncolites. The study of well preserved, silicified trilobites from low diversity, Bathyurus-dominated, Nearshore Biofacies faunas of Whiterockian and Chazyan age collected in six stratigraphic sections through the Sunblood Formation permits the recognition of three new Whiterockian zones, and two previously established Chazyan zones. The Bathyurus mackenziensis, Bathyurus sunbloodensis, and Bathyurus margareti zones (Whiterockian), together with the Bathyurus nevadensis and Bathyurus granu/osus zones (Chazyan) represent the Nearshore Biofacies components of a dual biostratigraphic scheme that considers both temporal and spatial distribution patterns, and are compositionally distinct from faunas in correlative strata around North America that represent other biofacies. Twenty-six species belonging to eighteen genera are described and illustrated. Ludvigsenella ellipsepyga is established as a new bathyurine genus, in addition to four new species of Bathyurus : Bathyurus mackenziensis, Bathyurus sunbloodensis, Bathyurus margareti and Bathyurus acanthopyga. Other genera present are: Basilicus, Isote/us, ///aenus, Bumastoides, Fail/eana, Phorocepha/a,Ceraurinella, Acanthoparypha, Xystocrania, Cydonocephalus, Ectenonotus, Pseudomera, Encrinuroides, Calyptaulax, Amphilichas and Hemiarges.

Why do some adults change their minds about what is important in the visual arts? : a case study

This-~-case study used ethnographic-methodo-logy. --The research project was an introductory study of one adult's present and past experiences with the visual arts, exploring, in particular, the causes and processes that were related to the individual's changes of mind in order to develop an understanding of why that individual had changed her mind about what was significant in the visual arts. The individual who provided the data was a solid supporter of art galleries: female, middle-aged, graduate of university and college, married with two children, and living in an urban community. The data were collected from two informal conversational interviews and from a written description of one change experience selected by the participant. The individual had positive experiences with art during early childhood, in elementary and secondary school, during university, in avocational drawing and painting studio courses, and in aesthetic experiences. All of these experiences have had individual effects and, together, they have had a cumulative effect on the development of the participant's opinions and ideas about the visual arts. The experiences which had the most effect on the development of the individual's perspectives on the visual arts were handson studio, educational, and aesthetic experiences. Further research is suggested to investigate why some adults change their minds about the visual arts.

Teacher attitudes and the emotionally-behaviourally disordered middle school student

Inclusionary practices prescribe that chl1dren, regardless of exceptional1ty shall benef1t from receiv1ng educational serv1ce 1n the context of the regular class sett1ng. The result1ng el1minat1on of separate spec1al classes could be v1ewed as an econom1c advantage. In point of fact, many school boards and d1str1cts 1n both Canada and the United States are mov1ng towards 1mplementat1on of inclusionary practice, possibly for the above stated reason. Regardless, 1nclusion as 1t relates to the emot1onally/behav1ourally disordered youth in our school systems may not be successful. Regular educat ion teachers may not be prepared profess1onally or personally to deal w1th this very special student population. Th1s study focused on teacher attitude 1n this regard. As well, poss1ble factors that may lead to successful 1nclusion of these students are examined. Of these, teacher exper1ence, educat10n spec1f1c to the d1sab1l1ty of emot1onal/behavioural d1sordered comb1ned w1th teacher self-perception of success appear to hold the greatest promise. In view of these findings, recommendat1ons are made for professional pract1ce and future research d1rect1ons.

Conflicting ideologies in early childhood education : an exploration of Reggio-inspired practice

Within the field of early childhood education, the ideologies of child development and its parent discipline, developmental psychology, dominate both theory and practice. In recent years, educators have attempted to reconceptualise early childhood education by adopting more progressive approaches to teaching and learning. The aim of this present research study was to critically examine the experiences of early childhood educators who have adopted a Reggioinspired approach to educating young children. To explore their experiences, an institutional ethnography was employed involving seven educators from a large child care organization in Hamilton, Ontario. In line with the intent ofthis study, qualitative data were collected through in-depth semi-structured interviews, participant-observations and textual analyses to explore the presence of developmental-psychological ideologies within early childhood education and Reggio-inspired practice. The present study also examined the challenges faced by educators who have adopted a Reggio-inspired approach. The results of this study indicate that ideologies associated with the developmental-psychological paradigm dominate the practice of early childhood educators and that the conflicting ideologies that surround Reggio educators may play a role in some of the challenges educators experience. The findings of this study thus demonstrate a need to adopt alternative approaches toward understanding both children and childhood, in both early childhood educational theory and practice.

Examining the potential application of childhood stature in assessing adolescent overweight and obesity

Background: Increasing Overweight and Obesity (OwOb) prevalence in pediatric populations is becoming a public health concern in many countries. The purpose of this study was to determine if childhood stature components, particularly the Leg Length Index (LLI = [height - sitting height]! height), were useful in assessing risk of OwOb in adolescence. Methods: Data was from a longitudinal study conducted in south Ontario since 2004. Approximately 2360 students had body composition measurements including sitting height and standing height at baseline. Among them, 1167 children (573 girls, 594 boys) who had weight and height measured at the 5 th year follow-up, were included in this analysis. OwOb was defined using age and sex specific BMI (kg!m 2 ) cut-off points corresponding to adults' BMI ~ 25. Results: Overall, 34% (n=298) of adolescents were considered as OwOb. The results from logistic regression analysis indicated that with 1 unit increase in LLI the odds of OwOb decreased 24% (Odds Ratio, [95% Confidence Interval], 0.76, [0.66-0.87]) after adjusted for age, sex and baseline waist circumference. Further adjusting for birth weight, birth order, breastfeeding, child's physical activity, maternal smoking, education, mother's age at birth and mother's BMI, did not change the relationship. Our results also indicated that mother's smoking status is associated with LLI. Discussion: Although LLI measured at childhood in this study is related to OwOb risk in adolescents, the underlying mechanism is unclear and further study is needed.

Early childhood pedagogical practice within a cultural kaleidoscope

Please consult the paper edition of this thesis to read. It is available on the 5th Floor of the Library at Call Number: Z 9999 E38 K39 2006

The Essence of Feeling a Sense of Community: A Hermeneutic Phenomenological Inquiry With Middle School Students and Teachers

In contemporary times, there is a compelling need to understand the nature of positive community relationships that value diverse others. This dissertation is a hermeneutic phenomenological inquiry into the essence of what it means to feel a sense of community. Specifically, I explored this phenomenon from the perspective of middle school teachers and students through the following questions: What meanings do students and teachers ascribe to feeling, experiencing, and developing a sense of community in their classes? To what extent do students’ and teachers’ ideas about feeling a sense of community include the acceptance of individual differences? Together these questions contributed to the overarching question, what is the essence of feeling a sense of community? As the data pool for the research, I used 192 essays and 218 posters from students who had been asked to write or draw about their visions of a positive classroom community where they felt a sense of community. I conducted 9 teacher interviews on the topic as well. My findings revealed one overarching ontology, Being-in-Relation, which outlined a full integration between individuality and community as a “way of being.” I also found five attributes that are present when individuals feel a sense of community: Supporting Others, Dialogue, An Ethic of Respect and Care, Safety, and Healthy Conflict. Contributions from this research include extensions to the literature about community; clarity for those who wish to establish a strong foundation of community relationships within formal and non-formal educational programs; insight that may assist educators, leaders, and policy makers within formal educational systems; and an opportunity to consider the extent to which the findings may point toward broader implications.

Back to School, Back to Normal? Exploring the Lived Experiences of Childhood Cancer Survivors and their Families Throughout the School Re-Entry Process

This study investigated parent and child perspectives of childhood cancer survivors' return to school. Four specific areas were examined including cognitive and academic concerns, social issues, perceived support, and the impact on siblings. Participants consisted of parents and childhood cancer survivors who were recruited through a regional parent support group. Data was collected during a focus group and interviews. Using a descriptive content analysis, results indicated that participants generally received the necessary resources, however issues such as consistency and having to advocate in order to attain these resources served as barriers for the families.