Exploring exploration : career identity development and temperment /

Career identity exploration is a central component of the lives of undergraduate university students. Although students are encouraged to explore, it is unclear whether different methods of exploration are better suited for certain individuals. In the present study, quantitative data were collected to examine the relationship between shyness and various methods of exploration. Two hundred fifty-seven university undergraduate students (29 male), ranging in age from 17-25 years completed a 60-minute self-report questionnaire. Shyness, identity, identity distress, subjective dimensions of exploration (satisfaction with exploration, reasons for not exploring, helpfulness of exploration methods), foci of exploration (non-social, social, self, and environmental), approaches to exploration (breadth, depth), and moderating variables (social support, sociability) were measured. Shyness was positively correlated with moratorium (high exploration, low commitment) and uncorrelated with the other identity statuses. Shyness was also positively correlated with identity distress, and a predicted interaction between shyness and identity diffusion predicting career identity distress was supported. Shyness was negatively correlated with satisfaction with amount of exploration engaged in to-date. In addition, shyness was correlated with the likelihood of selecting too stressful and too anxiety provoking as reasons for engaging in less exploration than one would like. Expected relationships between shyness and beliefs about, and engagement in, various methods of exploration were largely non-significant. Exceptions to this were the negative correlations between shyness and engagement in social exploration, and beliefs about the helpfulness of social self-exploration, both of which were significant at a trend level. A predicted interaction between shyness and social support predicting total social exploration was supported, showing that high social support buffers the negative relationship between shyness and exploration; such a moderating relationship did not exist, however, between sociability, shyness and social exploration. Results suggest that although shy university students are engaged in career exploration, they are experiencing feelings of distress and dissatisfaction with their career identity exploration and development. Thus, to help shy students become successfiil in their exploration, it is important for counsellors, family members, and peers to be aware of the feelings the individuals are experiencing and help them reduce the anxiety and stress associated with the exploration process. One promising method, supported by the results in this study, is by encouraging shy individuals to explore with social support.

School choice behaviour of independent school parents

One hundred and thirty-three parents of students new ~o ~ive independent schools in Ontario wer. surveyed to inve~tigate school choice behaviour. Paren~s were asKed to indicate their reasons for changing schooling, ~he criteria for selection o~ a school and the nature of the search process. Parents were also asKed to ranK speci~ic precipitants for change and criteria for choice. Spearman RanK Correla.tion tests were run comparing precipitants for change and criteria for choice for the entire sample and sub-groups based on socioeconomic status, gender of the child and family size. No signl~icant differences were found between the various $ub-groups, however, there was a strong positive correlation between precipitants for change and criteria for choice.Chi sq,uare tests were run compa.ring the number of information sources utilized in the search process, and a comparison was made between the importance of the va.rious sources of information. The majority of parents were classified as ac~ive searchers, researching one alternative more carefully than others. Socioeconomic status was the only factor to have a sign ific:ant- effect on the ranKing of information sources.

Grant Chapman, University of Southern California Law School graduation, 1925

Grant Chapman, University of Southern California Law School graduation, 1925.

Bowslaugh Family fonds, 1860-1861, 1868, 1876-1877, 1880-1882, 1886-1890, 1892-1893, 1895, 1898-1899, n.d.

Edward W. Bowslaugh (1843-1923) was the son of Jacob and Anna (Beamer) Bowslaugh. Edward Bowslaugh married Mary Southward, and the couple had six children, Edgar Morley, Edward Freeman, twins Alfred Malcolm and Alice Mary, Annie Olivia, John Jacob and Mabel Florence. Edward W. Bowslaugh was a farmer, contractor and owner of the Grimsby Planing Mills in Grimsby, Ont. and Bowslaugh’s Planing Mill in Kingsville, Ont. The mills manufactured door and sash trim and other wood related products. Some customers contracted the firm to provide wood products for cottages being built at Grimsby Park, the Methodist camp ground. Some time before 1885 Edward Bowslaugh and his family moved to Kingsville, Ont. to open up a new planing mill and door and sash manufactory. He later sold the Grimsby Planing Mills to Daniel Marsh. The diaries and account books include many names of workers as well as friends and family members residing in the Grimsby and Kingsville areas. James M. Bowslaugh (1841-1882) was the son of Jacob and Anna (Beamer) Bowslaugh. James married first Anna Catharine Merritt and after her death in 1875 he married Mary Gee in 1877. James and Anna had three children, Eliza, James Herbert, George Hiram, all died very young. James and Mary Gee had one son, Charles Leopold Kenneth Frederich Bowslaugh, b. 1881. James Bowslaugh was a farmer and lumberman, much like his younger brother Edward. James’ early diaries often note the activities of himself and his brother Edward. Both Edward and James were heavily involved in the Methodist church, teaching or leading Sunday school and attending prayer meetings. Alfred M. Bowslaugh b. 1873 was the son of Edward W. Bowslaugh and his wife Mary Southward. The school notebook is from his days as a student in Kingsville, Ont.

Rick Bell Family fonds, 1874-1875, 1879, 1884, 1886, 1888-1889, 1896, 1898, 1909-1910, 1939, 1945, n.d.

Lewis Tyrell married Jane Gains on August 31, 1849 in Culpeper Court House, Virginia. Jane Gains was a spinster. Lewis Tyrell died September 25, 1908 at his late residence, Vine St. and Welland Ave., St. Catharines, Ont. at the age of 81 years, 5 months. Jane Tyrell died March 1, 1886, age 64 years. Their son? William C. Tyrell died January 15, 1898, by accident in Albany, NY, age 33 years, 3 months. John William Taylor married Susan Jones were married in St. Catharines, Ont. on August 10, 1851 by William Wilkinson, a Baptist minister. On August 9, 1894 Charles Henry Bell (1871-1916), son of Stephen (1835?-1876) and Susan Bell, married Mary E. Tyrell (b. 1869?) daughter of Lewis and Alice Tyrell, in St. Catharines Ontario. By 1895 the Bell’s were living in Erie, Pennsylvania where children Delbert Otto (b. 1895) and Edna Beatrice (b. 1897) were born. By 1897 the family was back in St. Catharines where children Lewis Tyrell (b. 1899), Gertrude Cora (b. 1901), Bessie Jane (b. 1902), Charles Henry (b. 1906), Richard Nelson (b. 1911) and William Willoughby (b. 1912) were born. Charles Henry Bell operated a coal and ice business on Geneva Street. In the 1901 Census for St. Catharines, the Bell family includes the lodger Charles Henry Hall. Charles Henry Hall was born ca. 1824 in Maryland, he died in St. Catharines on November 11, 1916 at the age of 92. On October 24, 1889 Charles Hall married Susan Bell (1829-1898). The 1911 Census of Canada records Charles Henry Hall residing in the same household as Charles Henry and Mary Bell. The relationship to the householder is step-father. It is likely that after Stephen Bell’s death in 1876, his widow, Susan Bell married Hall. In 1939, Richard Nelson Bell, son of Charles Henry and Mary Tyrell Bell, married Iris Sloman. Iris (b. 22 May 1912 in Biddulph Township, Middlesex, Ontario) was the daughter of Albert (son of Joseph b. 1870 and Elizabeth Sloman, b. 1872) and Josie (Josephine Ellen) Butler Sloman of London, Ont. Josie (b. 1891) was the daughter of Everett Richard and Elizabeth McCarthy (or McCarty) Butler, of Lucan Village, Middlesex North. According to the 1911 Census of Canada, Albert, a Methodist, was a porter on the railroad. His wife, Josephine, was a Roman Catholic. Residing with Albert and Josie were Sanford and Sadie Butler and Sidney Sloman, likely siblings of Albert and Josephine. The Butler family is descended from Peter Butler, a former slave, who had settled in the Wilberforce Colony in the 1830s. Rick Bell b. 1949 in Niagara Falls, Ont. is the son of Richard Nelson Bell. In 1979, after working seven years as an orderly at the St. Catharines General Hospital while also attending night school at Niagara College, Rick Bell was hired by the Thorold Fire Dept. He became the first Black professional firefighter in Niagara. He is a founding member of the St. Catharines Junior Symphony; attended the Banff School of Fine Arts in 1966 and also performed with the Lincoln & Welland Regimental Band and several other popular local groups. Upon the discovery of this rich archive in his mothers’ attic he became passionate about sharing his Black ancestry and the contributions of fugitive slaves to the heritage Niagara with local school children. He currently resides in London, Ont.

Anne McPherson family fonds, 1852-2011 [non-inclusive]

Frank C. (Case) McCordick (1873-1946) was the son of William Henry (1849-1930) and Emily D. Howell (1851-1927) McCordick. William H. McCordick was in the coal business. The McCordick family included Frank Case, Mabel Gertrude, Ethel Howell and Arthur Stanley. Frank C. McCordick was educated in St. Catharines, and worked with his father in the coal business and eventually opened up a leather tanning operation. McCordick was active in the Lincoln Regiment and in 1906 was promoted to captain and in command of Company A, 19th Regiment. He was promoted to major and at the outbreak of war he was sent overseas as a commander of the 35th Battalion of the Canadian Expeditionary Forces (CEF). Upon arrival in France he was made officer commanding the 15th Battalion, King’s Own Yorkshire Light Infantry (KOYLI). After the war and his return to Canada he continued to play an active role in the local military units in the area as well as in Hamilton. After his retirement from the military in 1927 McCordick served as alderman and then mayor of St. Catharines from 1930 to 1931. He was a member of a large number of civic clubs, including St. Catharines Chamber of Commerce, Y.M.C.A., Lion’s Club, St. Catharines Golf Club, Detroit Boat Club, the St Catharines Club, as well as a member of several Masonic lodges. He continued to operate McCordick Tannery and other local investments. In 1903 Frank C. McCordick married May Beatrice Simson, daughter of Thomas E. Simson of Thorold. They had three children, E. (Edward) Frank McCordick, Bruce McCordick and (Margaret) Doris McCordick (m. Hubert Grigaut, d. 1977). The McCordick family resided at 82 Yates Street, near Adams Street. May Simson McCordick (b. 1873) was the daughter of Thomas Edward (1836-1908) and Julia Headlam (1844-1887) Simson of Thorold. Her siblings included: Edward, Frances, John, Augusta, Georgia and Gertrude. E. (Edward) Frank McCordick (1904-1980) was born in St. Catharines, Ont., attended Lake Lodge School in Grimsby, Ridley College in St. Catharines, Beechmont Preparatory School in England, Upper Canada College in Toronto and graduated from Royal Military College in Kingston, Ont. in 1925. Upon graduation he was made a lieutenant in the 10th (St. Catharines) Field Battery. In 1929 he married Helen Stanley Smith, daughter of Stanley George and Mary Walker Smith of St. Catharines. Col. McCordick, now promoted to Major, played an active role in the 10th (St. Catharines) Field Battery, being officer commanding the battery. In late 1939 McCordick headed to England for artillery tactical training and on December 6, 1939 the battery began the long trek overseas. McCordick saw action in Italy and in Holland. Upon his return to Canada at the end of the war he was the Liberal candidate in the federal election for Lincoln County. He remained active in the local military serving as honorary lieutenant-colonel of the 56th Field Regiment (ARCA) and in 1976 as the honorary colonel of the regiment. Col. McCordick held the Efficiency Decoration, the Order of the British Empire, granted in 1945 and was made an officer in the Order of St. John in 1978. He continued to serve his community in various capacities, including the Unemployment Insurance Canada Board, Royal Trust Company and the St. John Ambulance Society. He remained an active member of the alumni of Royal Military College, editing and compiling a newsletter and organizing reunion weekends. He kept in close contact with many of his classmates. Helen Stanley Smith McCordick lived in St. Catharines, Ont., attended Robertson School, and graduated from the University of Toronto in 1926 with a Bachelor of Arts degree in Modern Languages. During the war years (1939-1945) Helen was active in the Transport division of the local branch of the Canadian Red Cross and the Women’s Auxiliary of the 10th Field Battery. In 1932 E. Frank and Helen McCordick welcomed their only child, (Catharine) Anne McCordick. Helen continued to play an active role in her community until her passing in 1997. Stanley George Smith (1865-1960) was born in St. Catharines, Ont., the only child of William Smith (d. June 16, 1876) a native of Edinburgh, Scotland and his wife Hannah Louisa Maria Bulkeley a native of Fairfield, Connecticut. Stanley George Smith married Mary Walker of Guelph, Ont.(d. 1956) Mary was the daughter of Hugh and Elizabeth (d. 1924) Walker. Her siblings included Margaret, Agnes, Jessie, Isabella, Lorne, Ada, Alice, Eva, Alexander and George. Hugh Walker was a prominent fruit and vegetable merchant in Guelph. On 1904 their only child, Helen Stanley Smith was born. He was a post office clerk, and the treasurer for the James D. Tait Co. Ltd., a clothing and dry goods retailer in St. Catharines. The family lived at 39 Church Street in St. Catharines, Ont.

Closing the Summer Learning Gap for Vulnerable Children: An Examination of a Summer Family Literacy Program for Junior Kindergarten Children At-Risk for Reading Difficulties

The learning gap created by summer vacation creates a significant breach in the learning cycle, where student achievement levels decrease over the course ofthe summer (Cooper et aI., 2000). In a review of 39 studies, Cooper and colleagues (1996) specified that the summer learning shortfall equals at least one month loss of instruction as measured by grade level equivalents on standardized test scores. Specifically, the achievement gap has a more profound effect on children as they grow older, where there is a steady deterioration in knowledge and skills sustained during the summer months (Cooper et aI., 1996; Kerry & Davies, 1998). While some stakeholders believe that the benefits of a summer vacation overshadow the reversing effect on achievement, it is the impact of the summer learning gap on vulnerable children, including children who are disadvantaged as a result of requiring special educational needs, children from low socioeconomic backgrounds, and children learning English as a second language, that is most problematic. More specifically, research has demonstrated that it is children's literacy-based skills that are most affected during the summer months. Children from high socioeconomic backgrounds recurrently showed gains in reading achievement over the summer whereas disadvantaged children repeatedly illustrate having significant losses. Consequently, the summer learning gap was deemed to exaggerate the inequality experienced by children from low socioeconomic backgrounds. Ultimately, the summer learning gap was found to have the most profound on vulnerable children, placing these children at an increased chance for academic failure. A primary feature of this research project was to include primary caregivers as authentic partners in a summer family literacy program fabricated to scaffold their children's literacy-based needs. This feature led to the research team adapting and implementing a published study entitled, Learning Begins at Home (LBH): A Research-Based Family Literacy Program Curriculum. Researchers at the Ontario Institute designed this program for the Study of Education, University of Toronto. The LBH program capitalized on incorporating the flexibility required to make the program adaptable to meet the needs of each participating child and his or her primary caregiver. As it has been well documented in research, the role primary caregivers have in an intervention program are the most influential on a child's future literacy success or failure (Timmons, 2008). Subsequently, a requirement for participating in the summer family literacy program required the commitment of one child and one of his or her primary caregivers. The primary caregiver played a fundamental role in the intervention program through their participation in workshop activities prior to and following hands on work with their child. The purpose of including the primary caregiver as an authentic partner in the program was to encourage a definitive shift in the family, whereby caregivers would begin to implement literacy activities in their home on a daily basis. The intervention program was socially constructed through the collaboration of knowledge. The role ofthe author in the study was as the researcher, in charge of analyzing and interpreting the results of the study. There were a total of thirty-six (36) participants in the study; there were nineteen (19) participants in the intervention group and seventeen (17) participants in the control group. All of the children who participated in the study were enrolled in junior kindergarten classrooms within the Niagara Catholic District School Board. Once children were referred to the program, a Speech and Language Pathologist assessed each individual child to identify if they met the eligibility requirements for participation in the summer family literacy intervention program. To be eligible to participate, children were required to demonstrate having significant literacy needs (i.e., below 25%ile on the Test of Preschool Early Literacy described below). Children with low incident disabilities (such as Autism or Intellectual Disabilities) and children with significant English as a Second Language difficulties were excluded from the study. The research team utilized a standard pre-test-post-test comparison group design whereby all participating children were assessed with the Test of Preschool Early Literacy (Lonigan et aI., 2007), and a standard measure of letter identification and letter sound understanding. Pre-intervention assessments were conducted two weeks prior to the intervention program commencing, and the first set of the post-intervention assessments were administered immediately following the completion of the intervention program. The follow-up post-intervention assessments took place in December 2010 to measure the sustainability of the gains obtained from the intervention program. As a result of the program, all of the children in the intervention program scored statistically significantly higher on their literacy scores for Print Knowledge, Letter Identification, and Letter Sound Understanding scores than the control group at the postintervention assessment point (immediately following the completion of the program) and at the December post-intervention assessment point. For Phonological Awareness, there was no statistically significant difference between the intervention group and the control at the postintervention assessment point, however, there was a statistically significant difference found between the intervention group and the control group at the December post-intervention assessment point. In general, these results indicate that the summer family literacy intervention program made an immediate impact on the emergent literacy skills of the participating children. Moreover, these results indicate that the summer family literacy intervention program has the ability to foster the emergent literacy skills of vulnerable children, potentially reversing the negative effect the summer learning gap has on these children.

Two School Administrators’ Perspectives on How Intercultural Education is Promoted in Their Elementary Schools

This study examined the perspectives of 2 elementary school administrators (1 principal of a faith based school, and 1 vice-principal of a public school) towards intercultural education and how it was implemented in their schools. A generic qualitative research methodology guided this study. Face-to-face interviews that used a guide with open-ended questions were used to collect data. Participants were administrators in their respective schools, had been involved in intercultural activities at their school, and were professional acquaintances of the researcher. The interviews were digitally recorded and the interview transcripts were reviewed by participants to ensure accuracy. The administrators’ understanding of intercultural education tended to be limited to learning and celebration of various cultures. The intercultural education strategies used in the respective schools focussed on developing a knowledge base and provided limited intercultural interaction. The public school had greater resources available than the private faith-based school. However, the resources were not always used to facilitate intercultural education. Teachers and administrators were provided with very few professional development opportunities focussed on intercultural education.

Intracellular trafficking of protease : Activated Receptor 2 (PAR2) by members of sorting nexins family

Le dogme voulant que les récepteurs couplés aux protéines G (GPCRs) activent des voies de signalisation seulement lorsqu’ils sont localisés à la membrane plasmatique, a récemment été remis en question. Des données récentes indiquent que certains GPCRs peuvent également induire une réponse intracellulaire à partir des compartiments intracellulaires dont le noyau. Les récepteurs activés par la protéase (PAR) sont des membres de la famille GPCR. Les PARs sont activés par le clivage de la partie N–terminale du récepteur ce qui permet au ligand attaché sur le récepteur de se lier à sa poche réceptrice. Quatre PARs ont été décrits : PAR1, PAR2, PAR3 et PAR4. PAR2 peut susciter des effets mitogéniques et participer aux processus comme l’angiogenèse et l'inflammation. Alors que beaucoup d'effets intracellulaires de PAR2 peuvent être expliqués lorsqu’il est localisé à la membrane plasmatique, une fonction intracrine de PAR2 a aussi été proposée. Pourtant les mécanismes par lesquels PAR2 peut provoquer l’expression de gènes ciblés sont toujours inconnus. Le but de notre étude était de vérifier l’existence d’une population nucléaire de PAR2. Nous avons également émis l’hypothèse que les voies activées par l’activation de PAR2 dépendent de sa localization cellulaire. En utilisant des techniques de microscopie confocale et de "Western Blot" nous avons démontré la présence d’une population nucléaire de PAR2. À la suite de la stimulation de PAR2, nous avons observé une augmentation de la translocation du récepteur de la membrane plasmatique au noyau. En utilisant la technique de "RT – PCR", nous avons observé des rôles différents de PAR2 à la surface de la cellule et du noyau dans l’initiation de l’expression des gènes. Afin d’identifier les mécanismes responsables de la translocation nucléaire de PAR2, nous avons évalué l’implication des membres de la famille de "Sorting Nexins (SNX)" dans la translocation nucléaire de PAR2. "Sorting Nexins" est un groupe de protéines avec des fonctions de transport bien établies. SNX1 et SNX2 ont été identifiés comme responsables du transfert de PAR1 vers les lysosomes. SNX11 n'a pas encore été étudié et nous avons émis l’hypothèse qu'il pourrait être un autre membre de la famille des SNX impliqué dans la signalisation de PAR2. Pour ce faire, nous avons développé des "knockdowns" stables pour SNX1, SNX2 et SNX11 dans les cellules HEK293. En utilisant les essais d’immunofluorescence, "Western Blot" et de cytométrie en flux, nous avons déterminé que tous les trois membres du groupe SNX sont des partenaires d'interaction de PAR2. Toutefois, seul SNX11 se co-localise avec son partenaire au noyau et est responsable de sa translocation nucléaire. Les expériences de "RT - PCR" sur les lignées de cellule de SNXs "knockdowns" ont démontré que la fonction de PAR2 nucléaire dépend surtout de SNX11; néanmoins SNX1 et SNX2 peuvent aussi l’influencer, suggérant qu'ils font aussi partie du réseau signalétique de PAR2. En conclusion, PAR2 est déplacé de la membrane plasmatique à la membrane nucléaire après sa stimulation avec un agoniste. La translocation nucléaire de PAR2 par un mécanisme impliquant SNX11, initie des effets intracellulaires différents de sa signalisation membranaire. Mots clés : récepteurs couplés à la protéine G, “Sorting Nexins”, récepteurs activés par la protéase, translocation nucléaire, membrane nucléaire, signal nucléaire.

Structure quaternaire des récepteurs de chimiokines CXCR4 et CCR2 et interaction avec leurs effecteurs

Thèse réalisée en cotutelle avec l'université Montpellier2 dans le laboratoire de pharmacologie moléculaire de Jean-Philippe Pin à l'institut de génomique fonctionnelle (IGF), Montpellier, France.

Les filles sur le chemin de l’enseignement supérieur en Afrique subsaharienne : analyse de leurs trajectoires, représentations sociales de l’école et résilience à travers leurs récits biographiques

Les graphiques ont été réalisés avec le logiciel Alceste.

Exploring Rac GTPase regulation : the molecular mechanisms governing the DOCK180 and ELMO interaction and the role of this complex in Rac-mediated cell migration

Les protéines DOCK180 et ELMO coopèrent ensemble biochimiquement et génétiquement afin d’activer la GTPase Rac1 lors de plusieurs évènements biologiques. Toutefois, le rôle que jouent ces protéines dans la signalisation par Rac est encore mal compris. Nous émettons l’hypothèse que Dock180 agit comme activateur de Rac, alors que ELMO est requis pour l’intégration de la signalisation de Rac plutôt que son activation per se. Nous postulons que ELMO agit comme signal de localisation intracellulaire afin de restreindre de façon spatio-temporelle la signalisation de Rac en aval de Dock180, et/ou que ELMO agit comme protéine d’échafaudage entre Rac et ses effecteurs pour amplifier la migration cellulaire. Dans l’objectif nº 1, nous démontrons que le domaine PH atypique de ELMO1 est le site d’interaction principal entre cette protéine et DOCK180. De plus, nous démontrons que la liaison entre ELMO et DOCK180 n’est pas nécessaire pour l’activation de Rac, mais est plutôt essentielle pour faciliter la réorganisation du cytosquelette induite par l’activation de Rac en aval de Dock180. Ces résultats impliquent que ELMO pourrait jouer des rôles additionnels dans la signalisation par Rac. Dans l’objectif nº 2, nous avons découvert l’existence d’une homologie structurelle entre ELMO et un module d’autorégulation de la formine Dia1, et avons identifié trois nouveaux domaines dans la protéine ELMO : les domaines RBD, EID et EAD. De façon analogue à Dia1, nous avons découvert que ELMO à l’état basal est autoinhibé grâce à des intéractions intramoléculaires. Nous proposons que l’état d’activation des protéines ELMO est régulé de façon similaire aux formines de la famille Dia, c’est-à-dire grâce à des interactions avec d’autres protéines. Dans l’objectif nº 3, nous identifions un domaine RBD polyvalent chez ELMO. Ce domaine possède une double spécificité pour les GTPases de la famille Rho et Arf. Nous avons découvert que Arl4A agit comme signal de recrutement membranaire pour le module ELMO/DOCK180/Rac. Nos résultats nous permettent de supposer que d’autres GTPases pourraient être impliquées dans l’activation et la localisation de cette voie de signalisation. Nous concluons qu’à l’état basal, ELMO et DOCK180 forment un complexe dans lequel ELMO est dans sa conformation autoinhibée. Bien que le mécanisme d’activation de ELMO ne soit pas encore bien compris, nous avons découvert que, lorsqu’il y a stimulation cellulaire, certaines GTPases liées au GTP peuvent intéragir avec le domaine RBD de ELMO pour relâcher les contacts intramoléculaires et/ou localiser le complexe à la membrane. Ainsi, les GTPases peuvent servir d’ancrage au complexe ELMO/DOCK180 pour assurer une regulation spatiotemporelle adequate de l’activation et de la signalisation de Rac.

Kindergarten classroom engagement skills : the road to academic success in elementary school

Les caractéristiques de l’enfant à la maternelle prédisent le succès des transitions à travers les premières années scolaires ainsi que la poursuite académique à l’âge de 22 ans. Les habiletés en mathématiques et langagières à la maternelle sont étroitement liées au rendement scolaire. Cependant, il est également important de tenir compte du rôle de l’autocontrôle et de la maîtrise de soi dans la réussite académique. Spécifiquement, la capacité de suivre des instructions et travailler de manière autonome pourrait faciliter l’adaptation des enfants en milieu scolaire. La présente thèse examine la valeur potentielle de cibler l’engagement scolaire à la maternelle, sous forme d’orientation vers la tâche, pour améliorer l’ajustement académique des enfants au cours du primaire. Une première étude, a examiné si l’engagement scolaire à la maternelle est associé à un meilleur niveau de réussite scolaire et d’ajustement psychosocial à la quatrième année du primaire. Les résultats suggèrent que les habitudes de travail dès l’entrée à l’école représentent des prédicteurs robustes du rendement académique quatre ans plus tard. Un plus haut niveau d’engagement prédit également moins de comportements externalisés et de victimisation par les pairs en quatrième année. Ces résultats sont demeurés significatifs suite au contrôle statistique des habilités en mathématique, langagières et socio-émotionnelles des enfants ainsi que de facteurs de risques familiaux. Une deuxième étude a examiné l’origine de l’engagement scolaire au primaire. Cette étude a permis d’observer que le niveau de contrôle cognitif des enfants d’âge préscolaire représente un prédicteur significatif de l’engagement scolaire à la maternelle. Ces résultats suggèrent l’existence d’une continuité développementale du contrôle cognitif de la petite enfance à la maternelle, et que celle-ci pourrait servir de base pour le développement de bonnes habitudes de travail au primaire. Finalement dans une troisième étude, des analyses centrées sur la personne ont été effectués. Trois sous-groupes d’enfants ont été identifiés dans notre échantillon. Les résultats obtenus indiquent des trajectoires d’engagement bas, moyen et élevé respectivement, au primaire. Le faible contrôle cognitif et les facteurs de risques familiaux ont prédit l’appartenance à la trajectoire d’engagement faible. Dans l’ensemble, les résultats de ces trois études soulignent l’importance de tenir compte de l’engagement dans les évaluations de la maturité scolaire à la maternelle. Cette recherche pourrait également informer le développement de programmes d’interventions préscolaires visant à augmenter la préparation scolaire ainsi que la réduction des écarts au niveau de la réussite académique des enfants.

L’influence des habiletés de motricité fine et des capacités attentionnelles à la maternelle sur les habiletés d’écriture au début de l’école primaire.

Nous avons examiné la nature du lien, additif ou interactif, entre les capacités attentionnelles et les habiletés de motricité fine et leur influence sur les habiletés d’écriture ultérieures. Les mesures de l’échantillon (n=439) de l’étude montréalaise sur le préscolaire en milieu défavorisé (MLEPS) à la maternelle incluent des questionnaires aux enseignants, des évaluations sur la connaissance des nombres et du vocabulaire réceptif des élèves et caractéristiques familiales rapportées par les parents. En 3ème année, les mesures proviennent de questionnaires aux enseignants. Selon les résultats des régressions multiples de notre modèle, un élève qui avait de bonnes capacités d’attention ou de motricité fine à la maternelle, avait plus de chances d’avoir de bonnes habiletés d’écriture en 3ème année. L’interaction entre l’attention et la motricité fine était aussi significative, ce qui signifie que les capacités d’attention, avec l’influence des habiletés de motricité fine, prédisent davantage les habiletés d’écriture ultérieure. Il est pertinent de mesurer la réussite scolaire en écriture puisque les élèves à l’école peuvent investir de 31 à 60% de leur temps à réaliser des tâches motrices et 85% de celles-ci incluraient un crayon et du papier (McHale & Cermak, 1992). L’écriture serait aussi importante que les mathématiques et la lecture pour la réussite scolaire (Cutler & Graham, 2008). En identifiant les éléments clés de la réussite en écriture, nous pourrons mieux intervenir et soutenir les élèves, et ainsi, nous pourrions augmenter leurs chances de vivre des expériences positives à l’école, d’obtenir un diplôme et d’ intégrer le marché du travail.

The regulatory roles of APE1 and Prdx1 interaction

L’apurinic/apyrimidic endonuclease 1 (APE1) est une protéine multifonctionnelle qui joue un rôle important dans la voie de réparation de l’ADN par excision de base. Elle sert également de coactivateur de transcription et est aussi impliquée dans le métabolisme de l’ARN et la régulation redox. APE1 peut cliver les sites AP ainsi que retirer des groupements, sur des extrémités 3’ créées suite à des bris simple brin, qui bloquent les autres enzymes de réparation, permettant de poursuivre la réparation de l’ADN, puisqu’elle possède plusieurs activités de réparation de l’ADN comme une activité phosphodiestérase 3’ et une activité exonucléase 3’→5’. Les cellules de mammifères ayant subi un knockdown d’APE1 présentent une grande sensibilité face à de nombreux agents génotoxiques. APE1 ne possède qu’une seule cystéine située au 65e acide aminé. Celle-ci est nécessaire pour maintenir l’état de réduction de nombreux activateurs de transcription tels que p53, NF-κB, AP-1, c-Jun at c-Fos. Ainsi, elle se retrouve impliquée dans la régulation de l’expression génique. APE1 passe également à travers au moins 4 types de modifications post-traductionnelles : l’acétylation, la désacétylation, la phosphorylation et l’ubiquitylation. La façon dont APE1 est recrutée pour accomplir ses différentes fonctions biologiques demeure un mystère, bien que cela puisse être relié à sa capacité d’interaction avec de multiples partenaires différents. Sous des conditions de croissance normales, il a été démontré qu’APE1 interagit avec de nombreux partenaires impliqués dans de multiples fonctions. Nous émettons l’hypothèse que l’état d’oxydation d’APE1 est ce qui contrôle les partenaires avec lesquels la protéine interagira, lui permettant d’accomplir des fonctions précises. Dans cette étude nous démontrons que le peroxyde d’hydrogène altère le réseau d’interactions d’APE1. Un nouveau partenaire d’interaction d’APE1, Prdx1, un membre de la famille des peroxirédoxines responsable de récupérer le peroxyde d’hydrogène, est caractérisé. Nous démontrons qu’un knockdown de Prdx1 n’affecte pas l’activité de réparation de l’ADN d’APE1, mais altère sa détection et sa distribution cellulaire à l’intérieur des cellules HepG2 conduisant à une induction accrue de l’interleukine 8 (IL-8). L’IL8 est une chimiokine impliquée dans le stress cellulaire en conditions physiologiques et en cas de stress oxydatif. Il a été démontré que l’induction de l’IL-8 est dépendante d’APE1 indiquant que Prdx1 pourrait réguler l’activité transcriptionnelle d’APE1. Il a été découvert que Prdx1 est impliquée dans la régulation redox suite à une réponse initiée par le peroxyde d’hydrogène. Ce dernier possède un rôle important comme molécule de signalisation dans de nombreux processus biologiques. Nous montrons que Prdx1 est nécessaire pour réduire APE1 dans le cytoplasme en réponse à la présence de H2O2. En présence de Prdx1, la fraction d’APE1 présent dans le cytoplasme est réduite suite à une exposition au peroxyde d’hydrogène, et Prdx1 est hyperoxydé suite à l’interaction entre les deux molécules. Cela suggère que le signal, que produit le peroxyde d’hydrogène, sur APE1 passe par Prdx1. Un knockdown d’APE1 diminue la conversion de la forme dimérique de Prdx1 vers la forme monomérique. Cette observation implique qu’APE1 pourrait être impliquée dans la régulation de l’activité catalytique de Prdx1 en accélérant son hyperoxydation.