Developmental and individual differences in novelty and error detection in 10-year-old children and young adults /

Event-related potentials were recorded from 10-year-old children and young adults in order to examine the developmental dififerences in two frontal lobe functions: detection of novel stimuli during an auditory novelty oddball task, and error detection during a visual flanker task. All participants showed a parietally-maximal P3 in response to auditory stimuli. In children, novel stimuli generated higher P3 amplitudes at the frontal site compared with target stimuli, whereas target stimuli generated higher P3 amplitudes at the parietal site compared with novel stimuli. Adults, however, had higher P3 amplitude to novel tones compared with target tones at each site. Children also had greater P3 amplitude at more parietal sites than adults during the novelty oddball and flanker tasks. Furthermore, children and adults did not show a significant reduction in P3 amplitude from the first to second novel stimulus presentation. No age differences were found with respect to P3 latency to novel and target stimuli. These findings suggest that the detection of novel and target stimuli is mature in 10-year-olds. Error trials typically elicit a negative ERP deflection (the ERN) with a frontal-central scalp distribution that may reflect response monitoring. There is also evidence of a positive ERP peak (the Pe) with a posterior scalp distribution which may reflect subjective recognition of a response. Both children and adults showed an ERN and Pe maximal at frontal-central sites. Children committed more errors, had smaller ERN across sites, and had a larger Pe at the parietal site than adults. This suggests that response monitoring is still immature in 10-year-olds whereas recognition of and emotional responses to errors may be similar in children and adults.

Demolishing the Competition: The Association between Competitive Video Game Play and Aggression among Adolescents and Young Adults

The link between video game play and aggression is an important issue as video games The link between video game play and aggression is an important issue as video games are the fastest growing form of entertainment in the world. Past research on this association has been focused primarily on the link between video game violence and aggression; however, this research has confounded the effect of video game violence versus competition on aggression. The main goal of the current dissertation, therefore, was to examine the short- and long-term associations between competitive video game play and aggression. In addition, the longitudinal work on this association to date has been limited to adolescent samples, but not young adults. Thus, the second goal of the dissertation research was to investigate whether video game play predicts aggression in the long-term among young adults in addition to adolescents. To address these goals, three studies were conducted. Study 1 consisted of a series of experiments examining the short-term effect of video game violence versus competition on aggression. Study 2 examined the long-term association between competitive video game play and aggression among adolescents, and Study 3 examined this long-term link among young adults, in addition to adolescents. Taken together, the results of the three dissertation studies converged to suggest that video game competition, rather than violence, may be a stronger predictor of aggression in both the short- and long-term. Overall, the current research represents an important advance in our understanding of the association between video game play and aggression, and leads to a new direction in the video game and aggression literature. are the fastest growing form of entertainment in the world. Past research on this association has been focused primarily on the link between video game violence and aggression; however, this research has confounded the effect of video game violence versus competition on aggression. The main goal of the current dissertation, therefore, was to examine the short- and long-term associations between competitive video game play and aggression. In addition, the longitudinal work on this association to date has been limited to adolescent samples, but not young adults. Thus, the second goal of the dissertation research was to investigate whether video game play predicts aggression in the long-term among young adults in addition to adolescents. To address these goals, three studies were conducted. Study 1 consisted of a series of experiments examining the short-term effect of video game violence versus competition on aggression. Study 2 examined the long-term association between competitive video game play and aggression among adolescents, and Study 3 examined this long-term link among young adults, in addition to adolescents. Taken together, the results of the three dissertation studies converged to suggest that video game competition, rather than violence, may be a stronger predictor of aggression in both the short- and long-term. Overall, the current research represents an important advance in our understanding of the association between video game play and aggression, and leads to a new direction in the video game and aggression literature.

Perceptions of Adolescent Males and Their Parents as to Factors That Influence the Young Men's Academic Performance

Postsecondary enrolments of young males has been declining since the mid-1980s. The decline can be attributed, at least in part, to boys and young men being unable to compete for a fixed number of available places in institutions of higher learning, whether in community college or university. This inability to compete stems from their academic performance in secondary school. This study interviewed adolescent males and their parents as to their perceptions of a number of factors that may contribute to their academic performance. Those factors included noncognitive skills, dimensions of character, perceptions of teachers, general attitudes towards school, and likes and dislikes on a range of course subjects. One of the most important findings was that only one of the seven adolescent male participants was considering a future career that would require a university degree. Other findings showed the young men's noncognitive skills were weak, particularly in relation to time management skills and their unwillingness to ask for help with schoolwork and homework. Most of the young men expressed a dislike for mathematics beyond high school, a subject key to the study, of the natural sciences, engineering, technology, and business. Recommendations include school reforms both inside the classroom and beyond. Additionally, a framework using project management theory and practice has been proposed to improve noncognitive skills, dimensions of character, and executive function.

Metabolic, biochemical and molecular profiling of Catharanthus roseus flower cultivars and transformed hairy roots for monoterpenoid indole alkaloid accumulation /

Catharanthlls rosellS (L.) G Don is a commercially significant flower species and in addition is the only source of the monoterpenoid indole alkaloids (MIA) vinblastine and vincristine, which are key pharmaceutical compounds that are used to combat a number of different cancers. Therefore, procurement of the antineoplastic agents is difficult but essential procedure. Alternatively, CatharanthllS tissue cultures have been investigated as a source of these agents; however they do not produce vindoline, which is an obligate precursor to vinblastine and vincristine. The interest in developing high MIA cultivars of Catharantlws rosellS has prompted metabolic profiling studies to determine the variability of MIA accumulation of existing flowering cultivars, with particular focus on the vindoline component ofthe pathway. Metabolic profiling studies that used high performance liquid chromatography of MIAs from seedlings and young leaf extracts from 50 different flowering cultivars showed that, except for a single low vindoline cultivar (Vinca Mediterranean DP Orchid), they all accumulate similar levels of MIAs. Further enzymatic studies with extracts from young leaves and from developing seedlings showed that the low vindoline cultivar has a IO-fold lower tabersonine-16-hydroxylase activity than those of CatharanthllS rosellS cv Little Delicata. Additionally, studies aimed at metabolic engineering ofvindoline bios}l1thesis in Catharanthus rosellS hairy root cultures have been performed by expressing the last step in vindoline biosynthesis [Dcacetylvindoline-4-0- acetyltransferase (DAT)]. Enzymatic profiling studies with transformed hairy roots have confirmed that over-expressing DAT leads to lines with high levels of O-acetyltransferase activity when compared to non-expressing hairy roots. One particular DA T over111 expressing hairy root culture (line 7) contained 200 times the OAT activity than leaves of control lines. Additional MIA analyses revealed that DAT over-expressing hairy roots have an altered alkaloid profile with significant variation in the accumulation of h6rhammericine. Further analysis of transformed hairy root line 7 suggests a correlation between the expression of OAT activity and h6rhammericine accumulation with root maturation. These studies show that metabolic and selective enzymatic profiling can enhance our ability to search for relevant MIA pathway mutants and that genetic engineering with appropriate pathway genes shows promise as a tool to modify the MIA profile of Catharanthus roseus.

The effect of gregarine parasite infections, age, and diet on calling song structure and mating behaviour in the Texas field cricket, Gryllus integer

In the past ten years, many researchers have focussed their attention on parasites regarding the role they may play in causing variations in male secondary sexual traits and subsequent effects on female choice. Male age has also been suggested to be an important factor in female choice if old age reflects superior genes. This study investigated the effects that gregarine gut parasites, age, and diet have on the calling and mating behaviour of the male Texas field cricket, Gryllus integer. Male calling songs were recorded in the laboratory using a Digital Signal Processing Network. The song parameters measured were: pulse rate, pulse width, burst duration, pulses per burst, interburst interval, and percent missing pulses. The effects of parasite load and age on the various calling song parameters was investigated in crickets that were fed two different diets varying in nutritional quality. None of the calling song parameters were affected by either parasite load or age in either diet grou p. Courtship behaviour was ob served and recorded using an Eventlog recorder on an IBM computer in the laboratory. Females mated equally with paras(tized and unparasitized males and with old and young males The total duration and proportion of time spent performing each of 9 courtship displays were recorded for males on each diet. Only one display was affected by parasite load. Highly parasitized males fed the nutritionally inferior diet juddered for a proportionately shorter time than males with low parasite loads. Also, older males performed juddering and shaking antennae proportionally longer and juddering and raising wings for longer durations than younger males. Males that successfully mated were observed for performance of 8 post-copulatory guarding behaviour displays. None of the guarding behaviours were affected by parasite load. However, one display was affected by age, with older males performing guard turning for shorter durations than younger males. Results are discuss,ed in terms of the influence of parasites and age on female choice.

Examining sport commitment and intentions to participate in intramural sports : application of the Sport Commitment Model and the Theory of Planned Behaviour in a campus recreational sport setting

Fifty-six percent of Canadians, 20 years of age and older, are inactive (Canadian Community Health Survey, 200012001). Research has indicated that one of the most dramatic declines in population physical activity occurs between adolescence and young adulthood (Melina, 2001; Stephens, Jacobs, & White, 1985), a time when individuals this age are entering or attending college or university. Colleges and universities have generally been seen as environments where physical activity and sport can be promoted and accommodated as a result of the available resources and facilities (Archer, Probert, & Gagne, 1987; Suminski, Petosa, Utter, & Zhang, 2002). Intramural sports, one of the most common campus recreational sports options available for post-secondary students, enable students to participate in activities that are suited for different levels of ability and interest (Lewis, Jones, Lamke, & Dunn, 1998). While intramural sports can positively affect the physical activity levels and sport participation rates of post-secondary students, their true value lies in their ability to encourage sport participation after school ends and during the post-school lives of graduates (Forrester, Ross, Geary, & Hall, 2007). This study used the Sport Commitment Model (Scanlan et aI., 1993a) and the Theory of Planned Behaviour (Ajzen, 1991) with post secondary intramural volleyball participants in an effort to examine students' commitment to intramural sport and 1 intentions to participate in intramural sports. More specifically, the research objectives of this study were to: (1.) test the Sport Commitment Model with a sample of postsecondary intramural sport participants(2.) determine the utility of the sixth construct, social support, in explaining the sport commitment of post-secondary intramural sport participants; (3.) determine if there are any significant differences in the six constructs of IV the SCM and sport commitment between: gender, level of competition (competitive A vs. B), and number of different intramural sports played; (4.) determine if there are any significant differences between sport commitment levels and constructs from the Theory of Planned Behaviour (attitudes, subjective norms, perceived behavioural control, and intentions); (5.) determine the relationship between sport commitment and intention to continue participation in intramural volleyball, continue participating in intramurals and continuing participating in sport and physical activity after graduation; and (6.) determine if the level of sport commitment changes the relationship between the constructs from the Theory of Planned Behaviour. Of the 318 surveys distributed, there were 302 partiCipants who completed a usable survey from the sample of post-secondary intramural sport participants. There was a fairly even split of males and females; the average age of the students was twenty-one; 90% were undergraduate students; for approximately 25% of the students, volleyball was the only intramural sport they participated in at Brock and most were part of the volleyball competitive B division. Based on the post-secondary students responses, there are indications of intent to continue participation in sport and physical activity. The participation of the students is predominantly influenced by subjective norms, high sport commitment, and high sport enjoyment. This implies students expect, intend and want to 1 participate in intramurals in the future, they are very dedicated to playing on an intramural team and would be willing to do a lot to keep playing and students want to participate when they perceive their pursuits as enjoyable and fun, and it makes them happy. These are key areas that should be targeted and pursued by sport practitioners.

Ties From My Father: Personal Narrative as a Tool for Engaging Teenagers and Social Service Practitioners

The purpose of this project is to provide social service practitioners with tools and perspectives to engage young people in a process of developing and connecting with their own personal narratives, and storytelling with others. This project extensively reviews the literature to explore Why Story, What Is Story, Future Directions of Story, and Challenges of Story. Anchoring this exploration is Freire’s (1970/2000) intentional uncovering and decoding. Taking a phenomenological approach, I draw additionally on Brookfield’s (1995) critical reflection; Delgado (1989) and McLaren (1998) for subversive narrative; and Robin (2008) and Sadik (2008) for digital storytelling. The recommendations provided within this project include a practical model built upon Baxter Magolda and King’s (2004) process towards self-authorship for engaging an exercise of storytelling that is accessible to practitioners and young people alike. A personal narrative that aims to help connect lived experience with the theoretical content underscores this project. I call for social service practitioners to engage their own personal narratives in an inclusive and purposeful storytelling method that enhances their ability to help the young people they serve develop and share their stories.