Bacteriophages of Erwinia amylovora and their potential use in biological control

Forty-four bacteriophage isolates of Erwinia amy/ovora, the causal agent of fire blight, were collected from sites in and around the Niagara Region of Southern Ontario in the summer of 1998. Phages were isolated only from sites where fire blight was present. Thirty-seven of these phages were isolated from the soil surrounding infected trees, with the remainder isolated from aerial plant tissue samples. A mixture of six E. amy/ovora bacterial host strains was used to enrich field samples in order to avoid the selection bias of a single-host system. Molecular characterization of the phages with a combination of peR and restriction endonuclease digestions showed that six distinct phage types were isolated. Ten phage isolates related to the previously characterized E. amy/ovora phage PEa1 were isolated, with some divergence of molecular markers between phages isolated from different sites. The host ranges of the phages revealed that certain types were unable to efficiently lyse some E. amy/ovora strains, and that some types were able to lyse the epiphytic bacterium Pantoea agg/omerans. Biological control of E. amy/ovora by the bacteriophages was assessed in a bioassay using discs of immature pear fruit. Twenty-three phage isolates were able to significantly suppress the incidence of bacterial exudate on the pear disc surface. Quantification of the bacterial population remaining on the disc surface indicated that population reductions of up to 97% were obtainable by phage treatment, but that elimination of bacteria from the surface was not possible with this model system.

Teaching Principled negotiation skills to parents and their children : the impact of parental involvement /

This study explored the impact of training parents and children concurrently in principled negotiation skills for the purpose of developing negotiation skills and problem solving abilities in children. A second experimental group was utilized to determine the viability of negotiation skills training of junior elementary students for the purpose of improving problem solving and conflict resolving abilities. The student population in each experimental group was trained using The Program for Young Negotiators (Curhan, 1996). A control group was also established using the remaining grade four and five students attending the participating school. These students did not receive training as part of this study. Student group distribution was as follows: Experimental group 1 (students with parent participant) consisted of 10 (5 grade five and 5 grade 4 students), Experimental group 2 students without parent participant) consisted of 48 (20 grade 4 and 28 grade 5 students), and the Control group 3 (55 grade 4 and 5 students). The impact of training was measured using the Five Factor Negotiation Scale developed for use with the Program for Young Negotiators (Curhan, 1996). This measure was employed as a pre- and post-test questionnaire to the total student population, (113 students) to determine levels of ability in each of the key elements of negotiation, personal initiative, collaboration, communication, conflict based perspective taking, and conflict resolution approach (Nakkula & Nikitopoulos, unpublished). This measure has a coefficient alpha of .75 which is acceptable for this type of affective instrument. As well, open ended ability questions designed to measure ability, knowledge, and behaviour as they relate to negotiation skill application were given to the total student population, (113 students). Finally, journals were maintained by the students in both experimental groups, and informal feedback discussions were held with students and parents participating in the study.The intent of using both qualitative and quantitative measures was to provide an overall perspective of student abilities as they related to principled negotiation skills. While the quantitative measures were from the student perspective, more qualitative information was sought from parents and teachers through informal interviews, discussions, and use of confidential feedback cards. For analysis purposes, the ability questions were randomly selected for Experimental group 2 and Control group 3 in an effort to balance the groups more equitably with Experimental group 1. The findings of this study indicate that students of the junior elementary school age can be taught how to perceive conflict in a more constructive way. However, they are not as likely to use their skills when the conflict is with a sibling as they are with a peer, a teacher, or a parent. While no statistically significant differences between mean scores for Experimental groups 1 and 2 exist some subtle differences are noted. Overall, increases in mean scores for grade 4 students exceeded the increases for grade 5 students within Experimental group 1 . The implication being that younger students benefit more from having a parent trained in principled negoUation skills than older students. The skill level of a parent in principled negotiation can not be underesUmated. Without a consistent and effective role model the likelihood of developing student skill level to a point of automaticity is greatly reduced. Enough so that perhaps the emphasis should be placed on training parents more so than the students.

Attention focus and balance control in young and older adults

This thesis investigated attention focus and balance control in eighteen healthy young adults and eighteen healthy older adults. All participants performed sixteen consecutive trials of a balance task which involved standing for 30-s on an unstable platform that could rotate only in the roll direction. There were no attention focus instructions provided on any of the sixteen trials. Following the completion of the initial and final attempt in the series, participants reported "where" their attention had been focused when performing the task. The results showed differences in balance between young and older adults and improvements in balance with practice in both young and older adults. However, there were no differences in attention focus strategies between young and older adults. Both age groups directed attention to multiple sources during the balance task. An equal focus on internal (i.e., feet, trunk, and other body parts) and external (i.e., the platform) sources with little focus on events not related to the task dominated on the first attempt of the balance task. Focus on internal sources was maintained and focus on events not related to the task increased at the expense of focus on external sources on the final attempt of the balance task. Following the series of sixteen trials to establish "natural" attention focus, participants performed three randomly presented trials, each with specific attention focus instructions (i.e., think about minimizing movements of the feet, the trunk, or the platform). The results showed that, in contrast to the literature, instructions to focus on an internal source, the trunk, actually augmented control of the task as reflected in reduced trunk sway whereas instructions to focus on an internal source, the feet, or an external source, the platform, did not benefit performance on the task. Thus, the distance fi-om the interaction point of the body with the external source is critical and may not depend on whether the source is internal or external. Thus, a global attention focus instruction may not be beneficial and the nature of the task should be considered when adopting attention focus instructions for young and older adults.