Aspirations scolaires des parents et décrochage scolaire : le rôle du soutien des parents et des aspirations des adolescents

Cette étude porte sur le rôle des attitudes et des comportements parentaux dans le processus de décrochage scolaire au travers de deux objectifs. Le premier consiste à vérifier le rôle médiateur des aspirations scolaires de l’adolescent sur le lien entre les aspirations scolaires parentales pour leur enfant et le décrochage scolaire. Le second objectif vise à valider le rôle protecteur du soutien scolaire parental vis-à-vis du décrochage lorsque les aspirations scolaires des parents pour leur adolescent sont peu élevées. Les résultats ont été obtenus à partir de données longitudinales recueillies auprès de 4630 élèves québécois de secondaire pendant cinq ans. Ils mettent en évidence par l’emploi de régressions logistiques que les aspirations scolaires de l’adolescent médiatisent partiellement le lien entre les aspirations scolaires des parents et le décrochage scolaire. Comme attendu, le nombre de décrocheurs s’avère moins important dans la situation où les parents aux aspirations scolaires peu élevées soutiennent scolairement leur enfant. En revanche, les résultats n’ont pas permis de démontrer statistiquement le rôle protecteur du soutien scolaire parental car, contre toute attente, le nombre de décrocheurs s’est avéré également plus important lorsque des parents aux aspirations scolaires élevées soutiennent scolairement leur enfant. Quelques hypothèses sont avancées pour expliquer ce résultat contre intuitif. Les conclusions de cette étude laissent penser qu’accompagner les parents et leur enfant sur le niveau de leurs aspirations scolaires, permettrait de réduire le risque de décrochage scolaire. Elles ouvrent également sur de nouvelles perspectives quant au rôle modérateur du style parental et des difficultés scolaires de l’adolescent sur l’influence du soutien scolaire parental dans le processus de décrochage scolaire.

La santé mentale des femmes et des hommes de 65 ans et plus : rôle du stress quotidien et du soutien social

L’Étude sur la santé des aînés au Québec montre que les femmes âgées de 65 ans et plus ont un risque deux fois plus élevé de dépression et de troubles anxieux que les hommes âgés. La littérature scientifique des 40 dernières années suggère que le stress quotidien et le soutien social sont associés à la présence de ces troubles mentaux dans la communauté. L’objectif de la présente étude est de vérifier l’effet médiateur du stress quotidien et du soutien social sur l’association entre le genre et la dépression et les troubles anxieux. L’échantillon était composé d’individus de 65 ans et plus vivant en résidence privée au Québec. Des analyses de régression logistiques ont été menées afin d’identifier l’effet médiateur du stress et du soutien social en contrôlant pour des variables démographiques, socioéconomiques et de santé potentiellement confondantes. Les résultats de ces analyses ne permettent pas de conclure que le stress quotidien et le soutien social sont des variables médiatrices dans la relation entre le genre et la dépression ou entre le genre et les troubles anxieux chez les aînés. Puisque ces variables n’expliquent pas les différences de genre observées dans les prévalences de ces troubles psychiatriques d’autres avenues devront être étudiées.

Modelo del sistema de gestión de la calidad y el desempeño organizacional en la producción de petróleo

El proceso de cambio de una sociedad industrial a una sociedad del conocimiento, que experimenta el mundo globalizado en el siglo XXI, induce a las empresas y organizaciones a desarrollar ventajas competitivas y sostenibles basadas en sus activos intangibles, entre los cuales destacan los sistemas de gestión en general y los sistemas de gestión de la calidad (SGC) en particular. Las organizaciones dedicadas a la producción de petróleo están influenciadas por dicha tendencia. El petróleo es un recurso natural con reservas limitadas, cuya producción y consumo ha crecido progresivamente, aportando la mayor cuota (35 %) del total de la energía que se consume en el mundo contemporáneo, aporte que se mantendrá hasta el año 2035, según las previsiones más conservadoras. Por tanto, se hace necesario desarrollar modelos de producción innovadores, que contribuyan a la mejora del factor de recobro de los yacimientos y de la vida útil de los mismos, al tiempo que satisfagan los requerimientos de producción y consumo diarios de los exigentes mercados globales. El objeto de esta investigación es el desarrollo de un modelo de gestión de la calidad y su efecto en el desempeño organizacional, a través del efecto mediador de los constructos satisfacción del cliente interno y gestión del conocimiento en la producción de petróleo. Esta investigación de carácter explicativo, no experimental, transeccional y ex-postfacto, se realizó en la región petrolífera del lago de Maracaibo, al occidente de Venezuela, la cual tiene más de 70 años en producción y cuenta con yacimientos maduros. La población objeto de estudio fue de 369 trabajadores petroleros, quienes participaron en las mesas técnicas de la calidad, durante los meses de mayo y julio del año 2012, los cuales en su mayoría están en proceso de formación como analistas, asesores y auditores de los SGC. La técnica de muestreo aplicada fue de tipo aleatorio simple, con una muestra de 252 individuos. A la misma se le aplicó un cuestionario diseñado ad hoc, el cual fue validado por las técnicas de juicio de expertos y prueba piloto. El procedimiento de investigación se realizó a través de una secuencia, que incluyó la elaboración de un modelo teórico, basado en la revisión del estado del arte; un modelo factorial, sobre la base del análisis factorial de los datos de la encuesta; un modelo de regresión lineal, elaborado a través del método de regresión lineal simple y múltiple; un modelo de análisis de sendero, realizado con el software Amos 20 SPSS y finalmente, un modelo informático, realizado con el simulador Vensim PLE v.6.2. Los resultados obtenidos indican que el modelo teórico se transformó en un modelo empírico, en el cual, la variable independiente fue el SGC, la variable mediadora fue la integración de las dimensiones eliminación de la no conformidad, satisfacción del cliente interno y aprendizaje organizacional (ENCSCIAO) y la variable respuesta la integración de las dimensiones desempeño organizacional y aprendizaje organizacional (DOOA). Se verificó el efecto mediador del ENSCIAO sobre la relación SGC-DOOA con una bondad del ajuste, del 42,65%. En el modelo de regresión múltiple se encontró que las variables determinantes son eliminación de la no conformidad (ENC), conocimiento adquirido (CA) y conocimiento espontáneo (CE), lo cual fue corroborado con el modelo de análisis de sendero. El modelo informático se desarrolló empleando datos aproximados de una unidad de producción tipo, generándose cuatro escenarios; siendo el más favorable, aquel en el cual se aplicaba el SGC y variables relacionadas, reduciendo la desviación de la producción, incrementando el factor de recobro y ampliando la vida útil del yacimiento. Se concluye que la aplicación del SGC y constructos relacionados favorece el desempeño y la producción de las unidades de explotación de yacimientos petrolíferos maduros. Los principales aportes de la tesis son la obtención de un modelo de gestión de la producción de petróleo en yacimientos maduros, basado en los SGC. Asimismo, el desarrollo de un concepto de gestión de la calidad asociado a la reducción de la desviación de la producción petrolífera anual, al incremento del factor de recobro y al aumento de la vida útil del yacimiento. Las futuras líneas de investigación están orientadas a la aplicación del modelo en contextos reales y específicos, para medir su impacto y realizar los ajustes pertinentes. ABSTRACT The process of change from an industrial society to a knowledge-based society, which undergoes the globalized world in the twenty-first century, induces companies and organizations to develop a sustainable and competitive advantages based on its intangible assets, among which are noteworthy the management systems in general and particularly the quality management systems (QMS). Organizations engaged in oil production are influenced by said trend. Oil is a natural resource with limited reserves, where production and consumption has grown progressively, providing the largest share (35%) of the total energy consumed in the contemporary world, a contribution that will remain until the year 2035 according to the more conservative trust estimations. Therefore, it becomes necessary to develop innovative production models which contribute with the improvement of reservoirs´ recovery factor and the lifetime thereof, while meeting the production requirements and daily consumption of demanding global markets. The aim of this research is to develop a model of quality management and its effect on organizational performance through the mediator effect of the constructs, internal customer satisfaction and knowledge management in oil production. This research of explanatory nature, not experimental, transactional and expos-facto was carried out in the oil-region of Maracaibo Lake located to the west of Venezuela, which has more than 70 years in continuous production and has mature reservoirs. The population under study was 369 oil workers who participated in the technical quality workshops, during the months of May and July of 2012, the majority of which were in the process of training as analysts, consultants and auditors of the QMS. The sampling technique applied was simple random type. To a sample of 252 individuals of the population it was applied an ad hoc designed questionnaire, which was validated by the techniques of expert judgment and pilot test. The research procedure was performed through a sequence, which included the elaboration of a theoretical model, based on the review of the state of the art; a factorial model with based on factorial analysis of the survey data; a linear regression model, developed through the method of simple and multiple linear regression; a structural equation model, made with software °Amos 20 SPSS° and finally, a computer model, performed with the simulator Vensim PLE v.6.2. The results indicate that the theoretical model was transformed into an empirical model, in which the independent variable was the QMS, the mediator variable was the integration of the dimensions: elimination of non-conformity, internal customer satisfaction and organizational learning (ENCSCIAO) and the response variable the integration of the dimensions, organizational performance and learning organizational (DOOA). ENSCIAO´s mediator effect on the relation QMS-DOOA was verified with a goodness of fit of 42,65%. In the multiple regression model was found to be the determining variables are elimination of nonconformity (ENC), knowledge acquired (CA) and spontaneous knowledge (EC), which was verified with the structural equation model. The computer model was developed based on approximate data of an oil production unit type, creating four (04) scenarios; being the most favorable, that one which it was applied the QMS and related variables, reducing the production deviation, increasing the recovery factor and extending the lifetime of the reservoir. It is concluded that QMS implementation powered with the related constructs, favors performance and production of mature oilfield of exploitation reservoirs units. The main contributions of this thesis are obtaining a management model for oil production in mature oilfields, based on QMS. In addition, development of a concept of quality associated to reduce the annual oil production deviation, increase the recovery factor and increase oilfield lifetime. Future lines of research are oriented to the implementation of this model in real and specific contexts to measure its impact and make the necessary adjustments that might take place.

A perceção de suporte e a confiança organizacional: A sua importância na retenção dos recursos humanos

Dissertação de Mestrado apresentada ao ISPA - Instituto Universitário

Overqualification: Consequências no engagement e na satisfação laboral

Dissertação de Mestrado apresentada no ISPA - Instituto Universitário

As respostas comportamentais à violação do contrato psicológico, relação com o clima organizacional

Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção do grau de Mestre em Psicologia especialidade de Psicologia Educacional.

Effect of the mediator in feedback mode-based SECM interrogation of indium tin-oxide and boron-doped diamond electrodes

Indium tin-oxide (ITO) and polycrystalline boron-doped diamond (BDD) have been examined in detail using the scanning electrochemical microscopy technique in feedback mode. For the interrogation of electrodes made from these materials, the choice of mediator has been varied. Using Ru(CN) 4− 6 (aq), ferrocene methanol (FcMeOH), Fe(CN) 3− 6 (aq) and Ru(NH 3) 3+ 6 (aq), approach curve experiments have been performed, and for purposes of comparison, calculations of the apparent heterogeneous electron transfer rates (k app) have been made using these data. In general, it would appear that values of k app are affected mainly by the position of the mediator reversible potential relative to the relevant semiconductor band edge (associated with majority carriers). For both the ITO (n type) and BDD (p type) electrodes, charge transfer is impeded and values are very low when using FcMeOH and Fe(CN) 3− 6 (aq) as mediators, and the use of Ru(NH 3) 3+ 6(aq) results in the largest value of k app. With ITO, the surface is chemically homogeneous and no variation is observed for any given mediator. Data is also presented where the potential of the ITO electrode is fixed using a ratio of the mediators Fe(CN) 3− 6(aq) and Fe(CN) 4− 6(aq). In stark contrast, the BDD electrode is quite the opposite and a range of k app values are observed for all mediators depending on the position on the surface. Both electrode surfaces are very flat and very smooth, and hence, for BDD, variations in feedback current imply a variation in the electrochemical activity. A comparison of the feedback current where the substrate is biased and unbiased shows a surprising degree of proportionality.

Focus on opportunities as a mediator of the relationship between business owners' age and venture growth

Combining upper echelons and lifespan theories, we investigated the mediating effect of focus on opportunities on the negative relationship between business owners' age and venture growth. We also expected that mental health moderates the negative relationship between business owners' age and focus on opportunities. Path analytic findings based on data from 84 business owners (mean age = 44, range 24-74) supported these hypotheses. Findings suggest that focus on opportunities is a psychological mechanism that links business owners' age with venture growth. Our findings also indicate that mental health helps maintain a high level of focus on opportunities with increasing age.

Focus on opportunities as a mediator of the relationships between age, job complexity, and work performance

Focus on opportunities is a cognitive-motivational facet of occupational future time perspective that describes how many new goals, options, and possibilities individuals expect to have in their personal work-related futures. This study examined focus on opportunities as a mediator of the relationships between age and work performance and between job complexity and work performance. In addition, it was expected that job complexity buffers the negative relationship between age and focus on opportunities and weakens the negative indirect effect of age on work performance. Results of mediation, moderation, and moderated mediation analyses with data collected from 168 employees in 41 organizations (mean age = 40.22 years, SD = 10.43, range = 19-64 years) as well as 168 peers providing work performance ratings supported the assumptions. The findings suggest that future studies on the role of age for work design and performance should take employees' focus on opportunities into account.

Investigation of the effect of intrauterine inflammation and infection on fetal brain injury using human and animal models

In recent years, increased focus has been placed on the role of intrauterine infection and inflammation in the pathogenesis of fetal brain injury leading to neurodevelopmental disorders such as cerebral palsy. At present, the mechanisms by which inflammatory processes during pregnancy cause this effect on the fetus are poorly understood. Our previous work has indicated an association between experimentally-induced intrauterine infection, increased proinflammatory cytokines, and increased white matter injury in the guinea pig fetus. In order to further elucidate the pathways by which inflammation in the maternal system or the fetal membranes leads to fetal impairment, a number of studies investigating aspects of the disease process have been performed. These studies represent a body of work encompassing novel research and results in a number of human and animal studies. Using a guinea pig model of inflammation, increased amniotic fluid proinflammatory cytokines and fetal brain injury were found after a maternal inflammatory response was initiated using endotoxin. In order to more closely monitor the fetal response to chorioamnionitis, a model using the chronically catheterized fetal ovine was carried out. This study demonstrated the adverse effects on fetal white matter after intrauterine exposure to bacterial inoculation, though the physiological parameters of the fetus were relatively stable throughout the experimental protocol, even when challenged with intermittent hypoxic episodes. The placenta is an important mediator between mother and fetus during gestation, though its role in the inflammatory process is largely undefined. Studies on the placental role in the inflammatory process were undertaken, and the limited ability of proinflammatory cytokines and endotoxin to cross the placenta are detailed herein. Neurodevelopmental disorders can be monitored in animal models in order to determine effective disease models for characterization of injury and use in therapeutic strategies. Our characterizations of postnatal behaviour in the guinea pig model using motility monitoring and spatial memory testing have shown small but significant differences in pups exposed to inflammatory processes in utero. The data presented herein contributes a breadth of knowledge to the ongoing elucidation of the pathways by which fetal brain injury occurs. Determining the pathway of damage will lead to discovery of diagnostic criteria, while determining the vulnerabilities of the developing fetus is essential in formulating therapeutic options.

Mast cell mediator release in nonasthmatic subjects after endobronchial adenosine challenge

Background: Adenosine 5′-monophosphate (AMP) has been shown to cause bronchoconstriction in atopic subjects but to have no effect on nonatopic nonasthmatic subjects. Endobronchial AMP challenge has previously been shown to cause mast cell mediator release in asthmatic subjects, but it is unknown whether a similar response occurs in atopic nonasthmatic and nonatopic nonasthmatic control subjects who have no response to inhalation AMP challenge.

Objective: This study examined the change in mast cell–derived products after endobronchial saline challenge and AMP challenge in subjects with and without a positive inhalation response to AMP.

Methods: Inhalation challenge with AMP challenge was performed in normal, atopic nonasthmatic, and atopic asthmatic subjects. Levels of mast cell mediators were measured after endobronchial adenosine challenge and after placebo endobronchial saline challenge.

Results: There were significant increases in histamine, tryptase, protein, and prostaglandin D2 levels (P = .02, P = .02, P = .01, and P = .01, respectively) after AMP challenge compared with after saline challenge in nonatopic nonasthmatic subjects. There was no significant increase in any mediator in either of the other 2 groups.

Conclusion: This study suggests dissociation between mediator release and bronchoconstriction in response to AMP.

EFFECT OF IN-VIVO AND IN-VITRO LOVASTATIN TREATMENT ON MAST-CELL ACTIVATION

The hydroxymethylglutaryl coenzmye A (HMG CoA) reductase inhibitor lovastatin is used to treat hyperlipidaemia. This agent prevents the isoprenylation of some proteins involved in signal transduction processes and inhibits IgE-receptor-linked mediator release from RBL-2H3 cells. In this study the effect of in vivo and in vitro administration of lovastatin on histamine release from rat peritoneal mast cells was examined. Lovastatin (4 mg/kg/day for 2 weeks) inhibited histamine release induced by concanavalin A (con A) from rat peritoneal mast cells of Hooded-Lister rats and both homozygous lean and obese Zucker rats. In contrast, release induced by antirat IgE (anti-IgE) was only significantly inhibited in cells derived from Hooded-Lister rats and that induced by compound 48/ 80 was not altered. Lovastatin (20 mu M, 24 h, in vitro) caused a significant inhibition of the subsequent histamine release to con A, anti-IgE and compound 48/80 but not to the calcium ionophore A 23187. It is important to determine whether such inhibitory effects are also observed after the chronic, clinical administration of lovastatin and other HMG CoA reductase inhibitors.

Cognitive emotion regulation as a mediator between posttraumatic stress symptoms and hypomanic personality within a non-clinical population

Background: There is a high prevalence of traumatic life events within individuals diagnosed with bipolar disorder. However, currently there is limited theoretical understanding of this relationship. Aims: To explore whether non-clinical symptoms of posttraumatic stress have a direct effect on the non-clinical symptoms of bipolar disorder, or whether this relationship is mediated by cognitive emotion regulation strategies. Method: A cross-sectional design within non-clinical participants completing an online survey including the Impact of Events Scale, Cognitive Emotion Regulation Questionnaire and the Hypomanic Personality Scale. Results: Posttraumatic stress symptoms were associated with hypomanic personality. Intrusive memories contributed a small but significant proportion of the variance between these two measures. Rumination of negative emotions mediated the relationship between posttraumatic stress and hypomanic personality. Conclusions: The relationship between traumatic events and an increased prevalence of bipolar disorder remains poorly understood. Further research should explore rumination as a potential target for treatment within those suffering from both posttraumatic stress and bipolar disorder.

Hydrogen peroxide is a novel mediator of inflammatory hyperalgesia, acting via transient receptor potential vanilloid 1-dependent and independent mechanisms

Inflammatory diseases associated with pain are often difficult to treat in the clinic due to insufficient understanding of the nociceptive pathways involved. Recently, there has been considerable interest in the role of reactive oxygen species (ROS) in inflammatory disease, but little is known of the role of hydrogen peroxide (H(2)O(2)) in hyperalgesia. In the present study, intraplantar injection of H(2)O(2)-induced a significant dose- and time-dependent mechanical and thermal hyperalgesia in the mouse hind paw, with increased c-fos activity observed in the dorsal horn of the spinal cord. H(2)O(2) also induced significant nociceptive behavior Such as increased paw licking and decreased body liftings. H(2)O(2) levels were significantly raised in the carrageenan-induced hind paw inflammation model, showing that this ROS is produced endogenously in a model of inflammation. Moreover, superoxide dismutase and catalase significantly reduced carrageenan-induced mechanical and thermal hyperalgesia, providing evidence of a functionally significant endogenous role. Thermal, but not mechanical, hyperalgesia in response to H(2)O(2) (i.pl.) Was longer lasting in TRPV1 wild type mice compared to TRPV1 knockouts. It is unlikely that downstream lipid peroxidation was increased by H(2)O(2). In conclusion, we demonstrate a notable effect of H(2)O(2) in mediating inflammatory hyperalgesia, thus highlighting H(2)O(2) removal as a novel therapeutic target for anti-hyperalgesic drugs in the clinic. (C) 2008 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

The effect of phospholipase A2 from Crotalus durissus collilineatus on Leishmania (Leishmania) amazonensis infection

In this study, the effect of phospholipase A2 (PLA2) derived from Crotalus durissus collilineatus was evaluated in vitro and in vivo on experimental cutaneous leishmaniasis. The promastigote and amastigote forms treated with PLA2 presented increased growth rate. In vivo studies showed that PLA2-treated Leishmania (Leishmania) amazonensis promastigotes increased the size of lesions in BALB/c mice, and histopathological analysis showed numerous necrotic regions presenting a higher density of polymorphonuclear, mononuclear, and amastigote cells. Additionally, infected macrophages treated with PLA2 were able to generate prostaglandin E2 (PGE2). Cytokine quantification showed that the supernatant from infected macrophages presented moderate and high amounts of IL-2 and IL-10, respectively. However, in PLA2-treated infected macrophages, suppression of IL-2 levels occurred, but not of IL-10 levels. Observation also revealed that both the supernatant and lysate of L. (L.) amazonensis promastigotes exhibited PLA2 activity, which, in the presence of dexamethasone, showed no reduction in their activities; while glucocorticoid maintained the ability of promastigote forms to infect macrophages, which presented values similar to controls. In conclusion, the results indicate that PLA2 may be a progression factor for cutaneous leishmaniasis, since the PLA2 effect suppressed IL-2 levels and generated PGE2, an inflammatory lipid mediator.