269 research outputs found
L’effet médiateur du soutien et de la confiance dans la relation entre le leadership et l’engagement
L’objectif de cet article est d’évaluer, sur la base de la thĂ©orie de l’échange social, dans quelle mesure le soutien et la confiance envers le supĂ©rieur et l’organisation permettent d’expliquer l’influence de chacune des dimensions associĂ©es au leadership transformationnel, transactionnel et laisser-faire sur l’engagement affectif des employĂ©s. De nombreuses Ă©tudes montrent que ces diffĂ©rentes formes de leadership ont un impact important sur plusieurs attitudes et comportements des employĂ©s, mais encore très peu de chercheurs se sont intĂ©ressĂ©s aux processus par lesquels les leaders produisent de tels effets. Ă€ cet effet, nos rĂ©sultats font ressortir que la confiance et le soutien constituent des mĂ©canismes cruciaux pour expliquer l’effet du leadership sur l’engagement organisationnel des employĂ©s.Over the last few years, the transformational, transactional and laissez-faire leadership theory has attracted the attention of many researchers (Judge and Piccolo, 2004; Lowe and Gardner, 2000, Yammarino et al., 2005). Furthermore, numerous studies (Bycio, Hackett and Allen, 1995; Dumdum, Lowe and Avolio, 2002; Rafferty and Griffin, 2004; Yammarino, Spangler and Dubinsky, 1998) have shown that these three forms of leadership have a significant impact on several employee attitudes and behaviours, including affective organizational commitment, which is characterized by an individual’s emotional attachment to his company (Meyer and Allen, 1997). Nevertheless, there are still very few researchers taking an interest in the processes through which leaders can produce such effects (Bass and Riggio, 2006; Bono and Judge, 2003; Yukl, 2006). Only a few authors have tackled this problem, particularly by identifying empowerment (Avolio et al., 2004) and fairness (Pillai, Schriesheim and Williams, 1999) as mechanisms explaining the relationship between transformational leadership and employees’ affective commitment. We intend to build on these recent results in improving the understanding of this dynamic.Based on the social exchange theory (Blau, 1964), this research is aimed at exploring how supervisors can strengthen their employees’ affective commitment. More specifically, we will assess the extent to which support and trust can account for the influence of each of the dimensions associated with transformational, transactional and laissez-faire leadership has on commitment. These dimensions are: charisma, intellectual stimulation, individualized consideration, contingent reward, active management by exception, and passive avoidance.One of the primary contributions of this article resides in the fact that currently, there are still very few empirical research projects that have focussed on the effects of these dimensions on other variables, and that such research has only concentrated on the influence of global forms of leadership, and almost exclusively on the transformational form. However, recent works have indeed highlighted the importance of using specific dimensions rather than these three major forms of leadership since the later provide an imperfect and oversimplified image of all the leaders’ behaviours and potential (Antonakis, Avolio and Sivasubramaniam, 2003). In addition to filling a gap at this level, the second significant contribution of this project lies in the fact that, to our knowledge, no study has as yet validated the role of support as an intermediate mechanism lying between leadership and affective commitment.In concrete terms, we are first proposing that the charisma, intellectual stimulation, individualized consideration and contingent reward dimensions are positively related to employees’ perceived supervisor support and trust in their supervisor, whereas the active management by exception and passive avoidance dimensions are negatively related to those same two variables. Secondly, we are proposing that employees’ perceived organizational support and trust in their organization act as mediating variables between perceived supervisor support and trust in their supervisor and affective commitment, respectively.This research, which was conducted in the spring of 2004 among all the employees (excluding physicians) of a Quebec hospital center, allowed the collection of 568 questionnaires, representing a 46% response rate; 80% of the subjects in the sample were women, whose average age was 43, and who had been working in the organization for 12 years, on average. To test our hypotheses, confirmatory factorial analyses and structural equations were conducted, while controlling for gender and employment status (full time vs. part time).The results of the study indicate that only the charisma dimension seems to lead employees to trust their supervisor. This observation is particularly interesting for researchers with an interest in interpersonal trust since other studies have arrived at similar conclusions (Gillespie and Mann, 2004). However, our results indicate that charisma and contingent reward are positively related to perceived supervisor support whereas active management by exception is negatively associated to it. This observation is particularly important in that it provides responses to the theoretical arguments which were paving the way for such a possibility (Yammarino and Bass, 1990; Jung and Avolio, 2000). Lastly, this research shows that the constructs of perceived supervisor support and perceived organizational support constitute an important explanatory mechanism in the relationship between leadership and affective commitment. Trust in the organization also contributes to explaining the dynamic existing between leadership and commitment; however, it is not significantly influenced by trust in the supervisor.Our results open up several avenues of further research. Although our analyses have identified support and trust as intermediate mechanisms between leadership and commitment, other mediators could still account for this relationship. In addition to exploring this avenue, future research could simultaneously analyze the intermediate variables that have been identified to date in the literature (e.g., support, trust, fairness, empowerment) with respect to commitment, but also to other consequences which are often related to transformational and transactional leadership (e.g., satisfaction, mobilization, performance), in order to better understand their relative importance. Finally, this study has certain limitations, including the difficulty in generalizing results (sample composed of a single organization), the possible inflation of the strength of certain relationships (common variance bias) and the impossibility of inferring the causality of the observed relationships (cross-sectional design).El objetivo de este artĂculo es de evaluar, sobre la base de la teorĂa del intercambio social, en quĂ© medida el apoyo y la confianza hacia el superior y la organizaciĂłn permiten de explicar la influencia sobre el compromiso afectivo de los empleados de cada una de las dimensiones asociadas al liderazgo transformacional, transaccional y de “laisser-faire”. Numerosos estudios muestran que estas diferentes formas de liderazgo tienen un impacto importante sobre varias actitudes y comportamientos de los empleados, pero son pocos los investigadores que se interesan a los procesos por los cuales los lĂderes producen tales efectos. A este propĂłsito, nuestros resultados resaltan que la confianza y el apoyo constituyen mecanismos cruciales para explicar el efecto del liderazgo sobre el compromiso organizacional de los empleados
Pratiques en GRH et engagement des employés : Le rôle de la justice
En s’appuyant sur la thĂ©orie de l’échange social, cet article rend compte de l’effet mĂ©diateur des diffĂ©rentes formes de justice organisationnelle (distributive, procĂ©durale, interactionnelle) dans la relation entre les pratiques en gestion des ressources humaines (GRH) inspirĂ©es du modèle de Lawler (1986) et l’engagement affectif. Les 134 rĂ©pondants sont des directeurs aux services financiers d’une institution bancaire situĂ©e au QuĂ©bec. Des analyses de rĂ©gression, effectuĂ©es selon les procĂ©dures de Kenny, Kashy et Bolger (1998), ont confirmĂ© l’hypothèse de recherche. Ainsi, les rĂ©sultats font ressortir que la perception de chacune des formes de justice organisationnelle reprĂ©sente une variable mĂ©diatrice essentielle pour que la mise en place des pratiques en GRH contribue efficacement au dĂ©veloppement et Ă la consolidation de l’engagement des employĂ©s envers leur organisation.This study clarifies the role of organizational justice in the relationship between human resources management practices and commitment. Specifically, we develop and test a model in which the principal forms of justice (distributive, procedural and interactional) represent mediating variables in relationships between affective commitment and the four types of HRM practices (information sharing, knowledge development, non-monetary recognition and power sharing) included in the model developed by Lawler (1986). Meyer and Smith (2000) underscore that because few empirical studies have explored the relationship between HRM practices and commitment, it is important to determine how such practices influence employee commitment to organizations. Their results have shed light on the role of perception of organizational support and procedural justice as a mediating factor between certain HRM practices and organizational commitment.Consistent with the recommendation of these authors, our model rests on the theory of social exchange (Blau, 1964) and posits the three forms of organizational justice as mediating variables. Social exchange, unlike economic exchange, implies a relationship of exchange through unspecified obligations between the parties. Through the reciprocity norm, individuals in a climate of mutual trust maintain an exchange relationship with others to whom they feel obliged because they have received something from them. In a company, this pattern may correspond to organizations’ expectation that employees will develop favorable attitudes such as commitment in return for the introduction of HRM practices. Nonetheless, the specialized literature also clearly highlights theoretical links between social exchange and perceptions of organizational justice (Greenberg, 1987; Moorman, 1991). In this perspective, organizational justice encourages the development of effective commitment by enhancing employees’ feeling of reciprocity toward the organization, a sentiment created by the introduction of HRM practices.As part of this research project, a questionnaire was distributed in September 2001 to 232 managers of financial services of a private company operating in the Canadian banking sector. Of these questionnaires, 134 were returned, corresponding to a respectable response rate of 58%. To test our research hypothesis, we carried out hierarchical regression analyses according to the steps described by Kenny, Kashy and Bolger (1998). These analyses confirmed our hypothesis by demonstrating that each of the forms of justice indeed represents a mediating variable between the practices specified by Lawler (1986) and affective commitment. More specifically, we conclude that: (1) non-monetary recognition has an indirect effect on commitment through the three forms of justice; (2) interactional justice is a mediating variable between knowledge development and commitment; (3) procedural justice is a mediating variable between the practices of autonomy, initiative and commitment and (4) consulting has both a direct and indirect effect on affective commitment through procedural justice.Our observations corroborate the results of previous studies (Meyer and Smith, 2000; Schappe, 1996) that had affirmed a mediating effect of procedural justice between certain practices and organizational commitment. This study also makes a significant contribution with important theoretical and practical implications. First, our research supplements the literature on this topic by proposing an integrating model that measures the simultaneous effect of a larger number of practices than previous studies and that integrates the three principal forms of justice as a mediating variable. Moreover, our results demonstrate that organizations should pay attention to their employees’ perception of justice if they want to significantly increase the employees’ affective commitment by putting HRM practices in place. Moreover, regarding the individual effects of practices, our results suggest that organizations should first target non-monetary recognition practices, followed by power sharing practices (consultation, autonomy, initiative) and knowledge development practices.Lastly, our results confirm that the competitive advantage of successful firms mainly arises from their capacity to increase the added value of their human resources (Becker and Huselid, 1999). To attain organizational success, they must innovate in HRM notably by applying practices that favor the adoption of positive attitudes and behaviors toward the organization. Companies should thus encourage managers to act in compliance with equity, impartiality and respect to stimulate the affective commitment of their employees and maximize the investment required by the introduction of HRM practices.Apoyándose en la teorĂa del intercambio social, este artĂculo da cuenta del efecto mediador de las diferentes formas de justicia organizacional (distributiva, procesal, internacional) en la relaciĂłn existente entre las practicas de gestiĂłn de recursos humanos (GRH) inspiradas del modelo Lawler (1986) y el compromiso afectivo. Las 134 personas encuestadas son directores de servicios financieros de una instituciĂłn bancaria ubicada en la provincia de Quebec. Los análisis de regresiĂłn, efectuados segĂşn el procedimiento de Kenny, Kashy y Bolger (1998), han confirmado la hipĂłtesis de investigaciĂłn. AsĂ, los resultados destacan que la percepciĂłn de cada una de las formas de justicia organizacional representa una variable mediadora esencial para que la implantaciĂłn de prácticas de GRH contribuya eficazmente al desarrollo y a la consolidaciĂłn del compromiso de los empleados con su organizaciĂłn
Repenser le budget : la voie de l'informatique décisionnelle
Depuis de nombreuses années le budget est fortement critiqué, voire remis en cause. Les critiques les plus fréquentes portent sur la lourdeur de la démarche et sa rigidité qui ne permettraient pas d'adapter le budget aux évolutions de l'environnement ou qui conduiraient à des représentations simplifiées de l'organisation, pour ne pas dire simplistes. Aujourd'hui, l'informatique décisionnelle propose des outils spécifiques (BPM ou Business Process Management) qui pourraient modifier la démarche budgétaire. Après avoir décrit ces outils de Business Intelligence nous tenterons d'apprécier, au moyen d'une étude cas, leur impact sur la démarche budgétaire. Pour reprendre la terminologie de Simons, le budget qui n'est plus qu'un outil de diagnostic parmi de nombreux autres peut-il, grâce à ces technologies, redevenir l'outil interactif qu'il était à l'origine ?Budget; informatique décisionnelle; contrôle interactif; BPM
Compaction à Grande Vitesse de poudres de polymères semi-cristallins (mécanismes de frittage et modélisation du procédé)
La Compaction à Grande Vitesse (CGV) est un procédé efficace pour mettre en oeuvre par frittage, et dans un temps court, des poudres polymères semi-cristallins quelle que soit leur viscosité en partant d une température inférieure au point de fusion. L échauffement et la fusion du matériau est obtenu par une succession d impacts à une énergie donnée ce qui offre la possibilité de définir finement la quantité d énergie que l on souhaite apporter au matériau et la qualité du frittage. Une fusion partielle de la poudre permet de profiter de la cristallinité élevée de la poudre native, un compromis est alors possible entre de hautes propriétés élastiques et une ductilité élevée. La contre-partie de cette efficacité est une mise au point délicate du procédé. Dans le cas du polyéthylène ultra haute masse molaire (UHMWPE), il a été montré que le procédé permet une quasi-abstraction des effets de la masse molaire. Le frittage du UHMWPE demande seulement une réorganisation à courte distance des chaînes qui peut se faire dans un temps très limité. La cohésion de la poudre est assurée essentiellement par la cocristallisation et la création de nouveaux enchevêtrements. La modélisation du procédé a permis de comprendre comment l énergie cinétique lors des impacts est transformée en chaleur dans la poudre et elle a permis l établissement d un critère de processabilité par CGV. Ce critère de processabilité repose sur la déformabilité de la poudre contenu dans la matrice au moment de l impact. Celle-ci doit être suffisante pour que l énergie dissipée dans le matériau permette sa fusion en moins de cent coups. Ceci a permis de comprendre pourquoi le polyoxyméthylène peut difficilement se mettre en forme par CGV.High Velocity Compaction (HVC) is an efficient process to mold, in a short time, semicrystalline polymers powders any about their viscosity by starting from a temperature below melting point. Heating and melting occur by successive impacts at a preset energy that offers the possibility to set accurately the energy amount that we would bring to the material and the sintering quality. Partial melting of powder enable to take advantage of the high cristallinity of nascent powders, a compromise is possible between high elastic properties and high ductility. The flip-side of this efficiency is a delicate process settings. For the ultra high molecular weight polyethylene (UHMWPE), it has been shown that the process makes it possible a quasi abstraction of molecular weight effects. UHMWPE sintering needs only a short length reorganisation of chains that could be done in a really short time. Powder cohesion is essentially bring by cocrystallisation and by new entanglements creation. Process modelling allowed to understand how kinetic energy during hits is converted into heat in powder and it s enable to define a HVC processability criterion. This processability criterion rests on the strainability of powder place in a die during a hit. It has to be sufficient to the dissipated energy in material allows his melting in less than one hundred impacts. This criterion allows to understand why the polyoxymethylene is hard to mold by HVC.VILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF
On a species complex, Afzelia, in African forests of economic and ecological interest. A review
The purpose of this review is to provide a knowledge update and a comprehensive literature review of the genus Afzelia, a complex of sister species exploited for their timber in Central Africa. The distribution of Afzelia species in Africa suggests that the tree has made various
adaptations due to ecological factors. However, on the basis of only vegetative criteria, it is difficult to distinguish species in forest inventory, and this could compromise the sustainable management approach promoted by the populations of Central African countries. We show that the genus remains generally understudied, although some of its species are considered by the IUCN as being under threat. Therefore, the ecological and genetic aspects of our investigations should prove relevant to the future cultivation of Afzelia
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Multiple phosphorylation events control mitotic degradation of the muscle transcription factor Myf5.
BACKGROUND: The two myogenic regulatory factors Myf5 and MyoD are basic helix-loop-helix muscle transcription factors undergoing differential cell cycle dependent proteolysis in proliferating myoblasts. This regulated degradation results in the striking expression of these two factors at distinct phases of the cell cycle, and suggests that their precise and alternated disappearance is an important feature of myoblasts, maybe connected to the maintenance of the proliferative status and/or commitment to the myogenic lineage of these cells. One way to understand the biological function(s) of the cyclic expression of these proteins is to specifically alter their degradation, and to analyze the effects of their stabilization on cells. To this aim, we undertook the biochemical analysis of the mechanisms governing Myf5 mitotic degradation, using heterologous systems. RESULTS: We show here that mitotic degradation of Myf5 is conserved in non-myogenic cells, and is thus strictly under the control of the cell cycle apparatus. Using Xenopus egg extracts as an in vitro system to dissect the main steps of Myf5 mitotic proteolysis, we show that (1) Myf5 stability is regulated by a complex interplay of phosphorylation/dephosphorylation, probably involving various kinases and phosphatases, (2) Myf5 is ubiquitylated in mitotic extracts, and this is a prerequisite to its degradation by the proteasome and (3) at least in the Xenopus system, the E3 responsible for its mitotic degradation is not the APC/C (the major E3 during mitosis). CONCLUSION: Altogether, our data strongly suggest that the mitotic degradation of Myf5 by the ubiquitin-proteasome system is precisely controlled by multiple phosphorylation of the protein, and that the APC/C is not involved in this process.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Laser Scanning Microscopic Investigations of the Decontamination of Soot Nanoparticles from the Skin
Background/Aims: Airborne pollutants, such as nano-sized soot particles, are increasingly being released into the environment as a result of growing population densities and industrialization. They can absorb organic and metal compounds with potential biological activity, such as polycyclic aromatic hydrocarbons and airborne pollen allergens. Local and systemic toxicities may be induced in the skin if the particulates release their harmful components upon dermal contact. Methods: In the present study, skin pretreatments with serum and/or shield as barrier formulations prior to exposure and washing with a cleanser subsequent to exposure were evaluated as a protection and decontamination strategy using laser scanning microscopy. Results: The results indicate that while the application of serum and a cleanser was insufficient for decontamination, the pretreatment with shield prior to nanoparticle exposure followed by washing led to the removal of a considerable amount of the carbon black particles. The combined application of serum and shield before the administration of carbon black particles and subsequent washing led to their elimination from the skin samples. Conclusion: The application of barrier-enhancing formulations in combination with a cleanser may reduce the penetration of harmful airborne particulates by preventing their adhesion to the skin and facilitating their removal by subsequent washing with the cleanser
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