La fourmi d'Argentine (Linepithema humile) est une des espèces invasives parmi les plus nuisibles au monde. Dans le cadre des invasions biologiques, les résistances biotiques sont souvent les dernières barrières des écosystèmes. Une hypothèse, jamais testé in natura, de résistance de la part d'une fourmi du genre Tapinoma face à L. humile a été émise. Pour le démontrer, nous avons choisi d'expérimenter en laboratoire et in natura. Nos terrains d'études privilégiés ont été, outres des sites du littoral méditerranéen français, 4 îles situées en face du littoral envahi par la fourmi d'Argentine. Parmi celles-ci, deux contiennent à la fois la fourmi d'Argentine et des espèces du genre Tapinoma. L'identification difficile des espèces du genre Tapinoma étant sujette à une controverse scientifique, nous avons dû différencier de façon certaine cinq d'entre elles, par leurs morphologies et leurs signatures chimiques. En Provence, trois espèces ont été observées : T. erraticum, T. madeirense et T. nigerrimum. Sur l'île de Ratonneau, un suivi sur 2 ans de la vitesse d'invasion de L. humile en milieu naturel, avec ou sans T. nigerrimum, met en évidence une vitesse d'invasion très faible, voire un recul dans la zone à T. nigerrimum. Les colonies de T. nigerrimum de l'île de Ratonneau semblent faire obstacle à la progression de l'invasion. Des études comportementales préliminaires, conduites en laboratoire, entre fragments de nids de T. nigerrimum et L. humile nous avaient permis de confirmer les capacités de T. nigerrimum à résister face à l'invasive. Ainsi, les ouvrières T. nigerrimum défendent mieux leurs territoires, allant jusqu'à accaparer celui des L. humile. / The Argentine ant (Linepithema humile) is one of the world's worst invasive species. We used various analyses to determine its invasion pattern on the Provence coast, confirming the presence of a second supercolony. Chemical and behavioral analyses of worker interactions on the supercolony border identified a peaceful border zone. When biological invasion occurs, biotic resistance is often ecosystems' last defense. Could a dominant ant from Tapinoma genus resist L. humile invasion? To demonstrate this possibility, we conducted both laboratory and in natura experiements. Besides the invaded Mediterranean coast, we selected four nearby islands, two of which were found to contain both L. humile and Tapinoma spp. Identification of Mediterranean Tapinoma being controversial, we used both morphological and chemical analyses to ensure reliable discrimination. On the coast, we found T. erraticum, T. madeirense and T. nigerrimum. In natura, on Ratonneau Island, two-year field monitoring showed a slow rate of Argentine ant invasion and even retreat, faced with T. nigerrimum. T. nigerrimum colonies seem to block L. humile invasion. Laboratory behavioral studies between nests of T. nigerrimum and L. humile confirm T. nigerrimum's ability to stand up to Argentine ants: T. nigerrimum workers protect and defend their territories better, even taking over Argentine ant nests.

Actinobacillus actinomycetemcomitans is present in elevated proportions and numbers in dental bacterial biofilms of patients with localized aggressive periodontitis. This variant of periodontal disease, occurring in adolescents and young adults, is characterized by rapid and severe destruction of the connective tissues and bone supporting the teeth, eventually culminating in tooth loss. The cytolethal distending toxin (Cdt) is a newly discovered bacterial protein toxin, uniquely present in A. actinomycetemcomitans among all known to-date oral bacterial species. The Cdt has the capacity to inhibit mammalian cell growth, but its putative role in the pathogenesis of the disease is unclear. The aim of this in vitro work has been to study the effects of A. actinomycetemcomitans on periodontal connective tissue cell cultures, and to evaluate the possible involvement of its Cdt. A. actinomycetemcomitans inhibited the proliferation of gingival and periodontal ligament fibroblasts, as a result of a combined arrest at the G1 and G2/M phases of the cell cycle. This growth inhibition was non-lethal and the cells remained metabolically active, although their DNA synthesis was reduced. The intoxicated cells exhibited increased size and irregular structure, characterized by distension and elongation. This cellular enlargement occurred in both G1 and G2/M phase arrested cells. The Cdt of A. actinomycetemcomitans was responsible for the observed growth inhibition, as well as the concomitant morphological alterations. The possible induction of inflammatory cytokines related to bone resorption was investigated in response to A. actinomycetemcomitans, and the involvement of Cdt was evaluated. Extensive focus was given to the study of receptor activator of NF-κB ligand (RANKL) expression, a membrane-bound ligand that signals osteoclast progenitors to differentiate and fuse into mature osteoclasts, activating bone resorption. It was demonstrated that A. actinomycetemcomitans induced RANKL mRNA and protein expression in the cells studied, but did not affect the expression of its decoy receptor, osteoprotegerin. This induction was solely attributed to its Cdt, as demonstrated by the use of a cdt-knockout A. actinomycetemcomitans strain, purified recombinant Cdt, and antibodies blocking the Cdt. In addition, this event was not mediated by pro-inflammatory cytokines known to stimulate RANKL. Interleukin-6 mRNA and protein expression were also enhanced by A. actinomycetemcomitans, but Cdt had limited involvement in this enhancement. In conclusion, two distinct mechanisms by which A. actinomycetemcomitans Cdt may be involved in the pathogenesis of localized aggressive periodontitis are proposed. Firstly, the growth arrest of the resident fibroblasts may impair the physiological connective tissue remodelling equilibrium and lead to connective tissue attachment loss. Secondly, the induction of RANKL by these cells, residing in the proximity of the alveolar bone, may locally stimulate osteoclastogenesis and promote alveolar bone resorption. This work also provides further insights to the understanding of Cdt mechanisms of action, contributing to the global characterization of the toxin’s virulence.

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Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Multinational enterprises have been widely accused of using aggressive tax planning schemes to avoid paying tax all over the world. The purpose of this study is to analyse the methods used by multinational enterprises in the context of business restructurings to shift profits from high to low tax jurisdictions. Transactions between associated entities have generally been manipulated by applying non-arm’s length prices to these transactions, as well as devising agreements where the economic substance varies from the form of the transaction. The study aims to investigate some of the practical challenges faced by tax administrators in the application of the arm’s length principle. The study was conducted based on a literature review, as well as analysing specific examples reported in newspapers where multinational enterprises have used aggressive tax planning schemes to shift profits. International case law was also analysed to evaluate some of the factors considered by the courts in the determination of the arm’s length price. It was found that multinational enterprises definitely use aggressive tax planning schemes to shift profits. The practical challenges in the determination of arm’s length prices, complexity of the transactions involved, as well as a lack of resources, especially in the developing nations, are some of the factors that cause tax administrators to battle to find a solution to deter and detect these schemes. Other methods such as the unitary taxation method and the country by country reporting concept have been brought forward as alternatives to the arm’s length principle. These alternatives have been proposed in an effort to find a solution to the challenges posed by the arm’s length principle. Specific measures have also been recommended for developing nations’ tax administrators to resolve the issues that they currently experience in this context. / Thesis (MCom (South African and International Taxation))--North-West University, Potchefstroom Campus, 2013

Multinational enterprises have been widely accused of using aggressive tax planning schemes to avoid paying tax all over the world. The purpose of this study is to analyse the methods used by multinational enterprises in the context of business restructurings to shift profits from high to low tax jurisdictions. Transactions between associated entities have generally been manipulated by applying non-arm’s length prices to these transactions, as well as devising agreements where the economic substance varies from the form of the transaction. The study aims to investigate some of the practical challenges faced by tax administrators in the application of the arm’s length principle. The study was conducted based on a literature review, as well as analysing specific examples reported in newspapers where multinational enterprises have used aggressive tax planning schemes to shift profits. International case law was also analysed to evaluate some of the factors considered by the courts in the determination of the arm’s length price. It was found that multinational enterprises definitely use aggressive tax planning schemes to shift profits. The practical challenges in the determination of arm’s length prices, complexity of the transactions involved, as well as a lack of resources, especially in the developing nations, are some of the factors that cause tax administrators to battle to find a solution to deter and detect these schemes. Other methods such as the unitary taxation method and the country by country reporting concept have been brought forward as alternatives to the arm’s length principle. These alternatives have been proposed in an effort to find a solution to the challenges posed by the arm’s length principle. Specific measures have also been recommended for developing nations’ tax administrators to resolve the issues that they currently experience in this context. / Thesis (MCom (South African and International Taxation))--North-West University, Potchefstroom Campus, 2013

本論文嘗試以行為引發機制與行為抑制機制的觀點，探討非法且屬人際層面的男性攻擊行為，從中評估常表現攻擊行為個體的認知、情緒與行為缺陷。由於攻擊行為的特殊性，個體表現攻擊行為時，相關的行為機制包括表現該行為可能得到獎賞的行為引發機制﹔表現該行為可能得到懲罰的行為抑制機制﹔與攻擊他人時，被害者的非語文訊息引發的個體的暴力抑制機制。研究一根據暴力抑制機制的理論內容發展實驗工具，透過違反道德與違反慣例圖片組的呈現，了解高、中、低攻擊組的表現差異。結果發現高攻擊組對兩違反情境的嚴重程度評估較低，同時，在違反道德圖片組刺激下，高攻擊組表現較少的道德情緒與較少的同理行為。研究二則透過研究一發展的圖片組評估個體的暴力抑制機制運作能力，並結合Patterson與Newman的四階段理論發展實驗刺激，透過情境的操弄，了解高攻擊組之行為引發機制與行為抑制機制運作情形。結果發現經由兩套理論(暴力抑制機制與四階段理論)的結合，可將高攻擊組分為兩類，一類為暴力抑制機制運作正常，但行為引發機制運作過強﹔另一類為暴力抑制機制無法運作者。以認知、情緒與行為缺陷評估兩類高攻擊行為者發現，具有認知、情緒與行為缺陷的高攻擊行為者只有第二類。 / Based on a behavioral activation mechanism and two behavioral inhibition mechanisms, unlawful and interpersonal male aggression was studied. Moreover, the possibility of individuals’ cognitive, emotional, and behavioral deficiencies was evaluated. Due to the special quality of aggressive behavior, when a person acts aggressively, there will be three processes involved. They are the behavioral activation mechanism activated by reward, the behavioral inhibition mechanism induced by punishment, and the Violence Inhibition Mechanism (VIM) triggered by victims’ cues of distress. In order to study these three processes, two sets of pictures were developed from study 1 in order to evaluate how participants functioned their VIM. The results showed differences between High, Medium, and Low Aggression Group. The High Aggression Group evaluated incidents of moral/ conventional transgression less serious than the other two groups did. Also, they showed less moral emotions and less empathic behaviors than the other two groups did. Based on the sets of pictures developed from Study 1, a group of young offenders were divided into two groups based on their VIM functioning. Further, a survival game was developed from Patterson and Newman’s four-stage model. By manipulating situations to present reward/punishment, those young offenders showed different aggressive patterns. Young offenders with good VIM functioning behaved more aggressively when there were rewards. Relatively, young offenders with poor VIM functioning were less likely to be influenced by either reward or punishment. The implications were discussed in the article.

This study has developed a tool for explaining why employees fail to speak up with regard to work related criticism; there is a hidden policy of silence that teaches employees to remain silent. This hidden policy is here designated as the "Curriculum Silentium" and is described in detail on the basis of empirical and theoretical data. After identifying a gap between the intentionally and experienced policy for employees freedom of speech in organizations I suggest that there are on-going unofficial, partially hidden learning processes in the organizations. The overall research question is; How does the Curriculum Silentium; the hidden policy of silence among employees, look like?  I make an analytic construction of the hidden policy as if it were planned policy, using the didactic categories applicable to organizations. These didactic categories are: goals, content, teaching strategies and the motivation of employees. The empirical data was collected in three different organizations: an elementary school, a home for the elderly and a factory in the process industry, using qualitative methods such as interviews and observation. The theoretical foundation of the study is taken from existing theory within the field of work life research and educational science. The study is not a comparative study of the three organizations, but does involve a comparison of whether and how the Curriculum Silentium is expressed in three such different organizations. The challenge of examining hidden relationships in organizations was met through the development of guidelines for an analytical approach called a critical didactic relations analysis. The study concludes that a hidden policy of silence resembling that presented here exists in organizations where employees fail to voice working life related criticism.

This study investigates a dominance hierarchy in a male group of ruffed lemurs (Varecia spp.). I introduce a new method of data processing in unstable and inconsistent dominance hierarchy. Data were collected in the Ostrava ZOO during 30 days in the summer of 2009 and 28 days in the of winter 2010. The results demonstrate unusual structure in the sequences of agonistic interactions. The lemur group exhibited unstable and inconsistent dominance hierarchy with a low level of linearity. It appears that dominance hierarchy in ruffed lemurs is based on their social role in the family group and not on agonistic interactions.

The successful social development of adolescent girls is dependent on the acquisition of the skills required to face the challenges of adult life. Young girls are faced with the problem of a growing aggressive behaviour displayed by the girls who are supposedly their friends. This aggressive behaviour may negatively affect social, psychological or emotional development, possibly resulting in long term social adjustment problems. This investigation identifies the types and causes of aggressive behaviour displayed by adolescent girls, with the intention of ultimately identifying strategies to address aggressive behaviour. The implementation of a schoolbased approach, including all sectors involved in the education of the child in a whole-school programme to address aggressive behaviour, is recommended. Including all parties, firmly committed to addressing aggressive behaviour from a preventative perspective, may result in reducing aggressive behaviour and possibly provide adolescent girls with the coping skills required for successful social development. / Educational Studies / M.Ed. (Socio-Education)