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Att leda förändring med sensemaking som verktyg : En empirisk studie av förändringsledningen vid implementeringen av IT-systemet MetaVision på Akademiska sjukhusets centralintensiv, CIVA.Lyngarth, Viktoria January 2016 (has links)
Denna studie har genomförts med syftet att redogöra för hur förändringsledare arbetar samt vilka sensemaking-aktiviteter som bedrivs och är återkommande i förändringar gällande IT-implementeringar inom den svenska sjukvården. Studien grundar sig på en fallstudie där det som studeras är förändringsarbetet gällande implementeringen av IT-systemet MetaVision på Akademiska sjukhusets centralintensiv, CIVA. Uppsatsförfattaren har använt sig av metodtriangulering och således samlat in empirisk data från tre olika sorters källor. Semistrukturerade intervjuer har genomförts med ett urval av informanter baserat på deras profession, samt med projektets förändringsledare och superanvändare. Åtta stycken icke deltagande observationer har genomförts på avdelningen under fem veckors tid. Utöver det har dokument gällande förändringen samlats in. All insamlad data har sammanställts och analyserats. Studien mynnar ut en slutsats som belyser det faktum att förändringsledarens arbete och beteende är betydande för att förändringen ska gå att driva framåt samt att det finns specifika sensemaking-aktiviteter som ledare bör utföra under förändringsprocessens gång. Det går inte att urskilja enskilda aktiviteter som är viktigare än andra, då olika aktiviteter har olika betydelse i olika projektfaser. Detta beror på förändringens karaktär och vilken organisation som studeras. I denna specifika studie presenteras tre övergripande aktiviteter som varit betydande i det studerade projektets inledande uppstartsfas.
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Investigating literacy development among learners with a second language as medium of education : the effects of an emergent literacy stimulation program in Grade ROlivier, Johanna M. 12 1900 (has links)
Thesis (DPhil (General Linguistics))—University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Addressing the low literacy rates in South Africa poses a mountainous challenge.
However, identifying children at risk for reading difficulties and providing timely
and preventative intervention might be a good starting point to addressing this
challenge. This study aimed at making a contribution to the existing body of
literature on emergent literacy skills of learners who are educated in a second or
additional language. The study investigated English Language Learners’ (ELLs)
emergent literacy skills prior to entering Grade 1 and evaluated the effectiveness of
an evidence-based stimulation program in the South African context.
The main research question this study attempted to answer was: “What is the effect
of a stimulation program for emergent literacy skills in Grade R on the
development of literacy of English Language Learners in Grade 1?” In a quasiexperimental
design, ELLs’ emergent literacy skills were assessed with an adapted
version of the Emergent Literacy Assessment battery (Willenberg 2004) and were
compared to those of English first language (L1) and of ELL control groups, both
prior to and after an 8-week purpose-designed stimulation program. Results
indicated that while learners showed significant improvement on six out of the eight
subtests, the particular intervention program did not significantly improve ELLs’
emergent literacy skills (those pertaining to alphabet knowledge, phoneme
awareness, print awareness and oral language skills, amongst others) when
compared to learners in the respective control groups. When controlling for
receptive language abilities, English L1 learners did not perform any better than
their L2 peers on any of the eight measures of emergent literacy prior to
intervention. Furthermore, upon entering Grade 1, there was no statistical
significant difference in the performance of the English L1 learners and ELLs on
any of the eight subtests after intervention. Possible independent variables
contributing to the dearth of intervention effect included socio-economic status,
learners’ L1, and teacher and classroom specific characteristics. These variables
were addressed, and clinical implications for speech-language therapists with
regards to assessment, intervention, service delivery and outcome measures were
highlighted. / AFRIKAANS OPSOMMING: Die aanspreek van Suid-Afrika se geletterdheidsvraagstuk is ‘n reuse uitdaging. Die vroeë
identifisering van kinders met ‘n hoë risiko vir leesprobleme en die verskaffing van tydige
en voorkomende intervensie mag egter ‘n goeie beginpunt wees in die aanspreek van
hierdie uitdaging. Hierdie studie het gepoog om ‘n bydrae te lewer tot die bestaande
literatuur oor ontluikende geletterdheidsvaardighede van kinders wat in ‘n tweede of
addisionele taal onderrig word. Die studie het die ontluikende geletterheidsvaardighede
ondersoek van Graad R-leerders wat in Engels onderrig word, maar vir wie Engels nie
hul eerste taal is nie, asook die effektiwiteit van ‘n navorsingsgebaseerde
stimulasieprogram binne die Suid-Afrikaanse konteks.
Die hoof navorsingsvraag van die studie was: “Wat is die effek van ‘n stimulasieprogram
vir ontluikende geletterheidsvaardighede in Graad R op die ontwikkeling van
geletterdheid van Engels tweede taal (T2)-leerders in Graad 1?” In ‘n kwasieksperimentele
ontwerp is Engels T2-leerders se ontluikende geletterheidsvaardighede
met ‘n aangepaste weergawe van die Emergent Literacy Assessment Battery (Willenberg
2004) geëvalueer, en voor en na ‘n 8-week doelgerigte stimulasieprogram vergelyk met
die vaardighede van kontrolegroepe wat bestaan het uit Engels eerste taal (T1)-leerders
en Engels T2-leerders onderskeidelik. Alhoewel leerders ‘n beduidende verbetering in ses
van die agt subtoetse getoon het, het die spesifieke intervensieprogram nie T2-leerders in
die eksperimentele groepe se ontluikende geletterdheidsvaardighede beduidend verbeter
in vergelyking met leerders in die twee kontrole groepe nie (dit sluit in onder andere
alfabetkennis, foneembewustheid, drukbewustheid en orale taalvaardighede). Wanneer
daar vir reseptiewe taalvaardighede gekontroleer is, het die T1-leerders nie beduidend
beter gevaar as hul T2-portuurgroep op enige van die agt subtoetse van ontluikende
geletterdheid nie, en met toetrede tot Graad 1 was daar gevolglik geen statisties
beduidende verskil tussen die T1- en T2-groepe ten opsigte van enige van die agt
subtoetse nie. Moontlike onafhanklike veranderlikes wat tot hierdie gebrek aan
intervensie-effek kon bydra, sluit sosio-ekonomiese status, leerders se T1 en onderwyseren
klaskamer-spesifieke eienskappe in. Hierdie veranderlikes is aangespreek, en die
kliniese implikasies vir spraak-taalterapeute met betrekking tot evaluasie, intervensie,
dienslewering en die noukeurige meting van uitkomste is toegelig.
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Measuring and Influencing Sequential Joint Agent BehavioursRaffensperger, Peter Abraham January 2013 (has links)
Algorithmically designed reward functions can influence groups of learning agents toward measurable desired sequential joint behaviours. Influencing learning agents toward desirable behaviours is non-trivial due to the difficulties of assigning credit for global success to the deserving agents and of inducing coordination. Quantifying joint behaviours lets us identify global success by ranking some behaviours as more desirable than others. We propose a real-valued metric for turn-taking, demonstrating how to measure one sequential joint behaviour. We describe how to identify the presence of turn-taking in simulation results and we calculate the quantity of turn-taking that could be observed between independent random agents. We demonstrate our turn-taking metric by reinterpreting previous work on turn-taking in emergent communication and by analysing a recorded human conversation. Given a metric, we can explore the space of reward functions and identify those reward functions that result in global success in groups of learning agents. We describe 'medium access games' as a model for human and machine communication and we present simulation results for an extensive range of reward functions for pairs of Q-learning agents. We use the Nash equilibria of medium access games to develop predictors for determining which reward functions result in turn-taking. Having demonstrated the predictive power of Nash equilibria for turn-taking in medium access games, we focus on synthesis of reward functions for stochastic games that result in arbitrary desirable Nash equilibria. Our method constructs a reward function such that a particular joint behaviour is the unique Nash equilibrium of a stochastic game, provided that such a reward function exists. This method builds on techniques for designing rewards for Markov decision processes and for normal form games. We explain our reward design methods in detail and formally prove that they are correct.
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The social character of organizational change : strategizing as emergent practiceBurger, Martinus Charl January 2010 (has links)
Increasingly, researchers on strategy are turning away from the highly abstracted and de-humanized components that seem to typify the macro approach to strategy. This movement is at least partially brought about by a philosophical recognition that the emergent and unpredictable nature of organizational life is fast exposing the constraints of an approach to strategy that is based on the values of rationality, predictability and control. In this thesis I argue that organizational change in general and the act of strategizing in particular can be thought of as a social, transformative and emergent process as opposed to the overly orderly, rational, formative and/or humanistic views on strategy presented by systemically oriented theorists. I draw on the theory of complex responsive processes of relating as espoused by Stacey, Griffin and Shaw (2000) and specifically on Stacey’s (2003, 2007) substantial contribution to the field of strategic management. By utilizing a reflexive research methodology I describe the arduous social and emergent process of transformation in my practice and identity (observable in subtle changes in disposition, language and assumptions) as I begin to act into the understanding of strategizing as an ongoing, incomplete, social process. In doing this, I am suggesting that the narrated accounts of our shifts in practice due to us knowing differently are important contributions in the process of transforming our theories on and beliefs around strategy. These accounts should not be seen as premature attempts at methodological frameworks, but rather as explorative participation in the emergent transformation of a radical, social approach to strategizing. I engage critically with the notion of strategy-as-practice and suggest a review of the fundamentally rational and formative assumptions still prevalent in the work of researchers like Johnson, Melin and Whittington (2003) and Samra- Fredericks (2003). Whilst acknowledging the role of culturally mediated dispositions in the ongoing transformation of organizations advocated by Chia and Holt (2006) and Chia and MacKay (2007), I argue for the paradoxical and therefore simultaneous occurrence of habitual and mindful actions by people strategizing as opposed to the authors’ suggestion of a predominantly mindless experience of organizational change. Finally, I turn to Stacey’s (2007) question as to why people continue to make long-term forecasts if their usefulness is so obviously limited. Whilst understanding his frustration, I argue that there is value nevertheless in engaging in strategy making albeit not for the rationalist reasons usually stated. In my view the real value of strategising is to be found in two areas: first in the social activity that goes into creating these documents, and second: the documents not only serve as markers in an ongoing process of strategising; they also give us a way of ‘going on’ and taking the next step.
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Analyse des agents de chimiothérapie par extraction sur phase solide automatisée couplée à la chromatographie liquide et la spectrométrie de masse en tandem (SPE-LC-ESI-MS/MS)Rabii, Farida 12 1900 (has links)
Les dernières décennies ont été marquées par une augmentation du nombre des cas de cancers, ce qui a subséquemment conduit à une augmentation dans la consommation des agents de chimiothérapie. La toxicité et le caractère cancérogène de ces molécules justifient l’intérêt crucial porté à leur égard. Quelques études ont fait l’objet de détection et de quantification des agents de chimiothérapie dans des matrices environnementales.
Dans ce projet, une méthode utilisant la chromatographie liquide couplée à la spectrométrie de masse en tandem (LC-MS/MS) précédée d’une extraction sur phase solide (SPE) automatisée ou en ligne a été développée pour la détection et la quantification d’un groupe de six agents de chimiothérapie. Parmi ceux-ci figurent les plus utilisés au Québec (gemcitabine, méthotrexate, cyclophosphamide, ifosfamide, irinotécan, épirubicine) et présentant des propriétés physico-chimiques et des structures chimiques différentes. La méthode développée a été validée dans une matrice réelle représentant l’affluent d’une station d’épuration dans la région de Montréal. Deux des six composés cytotoxiques étudiés en l’occurrence (cyclophosphamide et méthotrexate) ont été détectés dans huit échantillons sur les neuf qui ont été recensés, essentiellement au niveau de l’affluent et l’effluent de quelques stations d’épuration de la région de Montréal. Les résultats des analyses effectuées sur les échantillons réels ont montré qu’il n’y avait pas de différence significative dans la concentration entre l’affluent et l’effluent, et donc que les systèmes d’épuration semblent inefficaces pour la dégradation de ces molécules. / The last few decades have been marked by an increase in the number of cancer cases, which subsequently led to an increase in the consumption of chemotherapeutic agents. The toxicity and the carcinogenicity of these molecules justify the increased interest. Few studies have been conducted to detect and quantify chemotherapeutic agents in environmental matrices.
In this project, a method using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) preceded by an online solid-phase extraction (SPE) has been developed for the detection and quantification of a group of six chemotherapeutic agents, which are among the most commonly used in Quebec (gemcitabine, methotrexate, cyclophosphamide, ifosfamide, irinotecan, epirubicin) and having different physico-chemical properties and different chemical structures. The developed method was validated in a real water matrix representing the influent of a sewage treatment plant in the Montreal area. Two of the six studied cytotoxic agents (cyclophosphamide and methotrexate) were detected in eight samples of the nine taken mainly at the influent and effluent of some treatment plants in the Montreal area. The results of the analysis of real samples showed that there was no significant difference in concentration between the influent and effluent. This also demonstrates the inadequacy of the current wastewater treatment approaches to remove those compounds.
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Successful Emergent Literacy Head Start Teachers of Urban African American Boys Living in PovertyHolland, John Michael 27 November 2012 (has links)
This integrated methods study used a sequential explanatory design to explore the culturally relevant teaching beliefs of successful emergent literacy Head Start teachers of urban African American boys living in poverty. The study utilized emergent literacy gain scores as a measure of success, a survey of culturally relevant teaching beliefs to describe variation in beliefs within the sample, and two rounds of interviews to explore the context of teacher agency with urban African American boys living in poverty. The four teachers interviewed expressed culturally relevant beliefs integral to their teaching practices. These beliefs were conveyed through descriptions of relationships with parents in and out of the classroom, through of the conditions and challenges of poverty in students' and parents' lives, and through close relationships with parents. The effect of conducting home visits on teachers' identities and the influence of the setting of Head Start on teachers' beliefs and agency were emergent themes in the interviews. The participants used language that seemed to indicate culturally relevant and warm demander approaches to understanding the relationship between student behavior and student engagement and in descriptions of the relationships with parents. The value of teachers' relationships with their students' parents was the most pronounced aspect of successful teaching in Head Start as expressed by the participants. The process of communication among parents, students, and teachers was described as important to student learning. The participants' expressed a variety of approaches to how they understood student behavior, boys' social emotional development, and classroom practices. These Head Start teachers described boys as more active than girls, as more aggressive than girls, and sometimes more challenged to express strong emotions with language than girls. This study provides some insight into the role that culturally relevant teaching beliefs play in Head Start teachers' successful
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Practicing peacebuilding differently : a legal empowerment project, a randomised control trial and practical hybridity in LiberiaGraef, J. Julian January 2014 (has links)
Hybridity, as it is currently understood in the Peace and Conflict Studies (PCS) and International Relations (IR) literature, is defined by the complex interactions between ‘the liberal peace' and ‘the local'. However, under this theoretical liberal-local rubric, the ways in which power is practiced has already been determined; how resistance is expressed and the forms it assumes have already been established. While it has yielded numerous important insights into how power circulates and resistance manifests in peacebuilding operations, the theoretical approach conceals other significant dynamics which escape detection by ‘the liberal peace' and ‘the local'. However, these undetected dimensions of hybridity comprise the very processes that emerge in ways which destabilise the boundaries between ‘the liberal peace' and ‘the local' and reshape the contours of the emerging post-liberal peace. Instead of accepting the liberal-local distinction which defines this theoretical hybridity, this thesis advances an alternative methodological approach to exploring the tensions at play in peacebuilding projects. Rather than deploying theoretical distinctions in order to explain or understand complex hybrid processes, this thesis develops a methodological strategy for exploring the tensions between how actors design a peacebuilding project and how that project changes as actors work to translate that project into complex, everyday living sites (Callon, 1986; Law, 1997; Akrich, 1992). This tension is expressed as practical hybridity. The process of practical hybridity unfolds as the concrete material changes, modifications, and adaptations that emerge as actors appropriate and contingently translate organised practices in new ways and for different purposes. Through an ongoing process of practical hybridity, the boundaries and distinction which define the distinction between ‘the liberal peace' and ‘the local' become increasingly unstable. Amidst this instability, the practices which characterised ‘the liberal peace' are becoming stretched into a post-liberal peace. Drawing on the work of Richmond (2011a; Richmond & Mitchell, 2012), Latour (1987b; 1988; 2004), and Schatzki (2002), and based on over five months of field research, this this thesis traces the process of practical hybridity at play during the implementation and evaluation of a peacebuilding project in Liberia. I participated as a research assistant on a Randomised Control Trial (RCT), implemented by a small research team under the auspices of the Oxford University's Centre for the Study of African Economies (CSAE). The team was assessing the impact of a legal empowerment programme managed by The Carter Center: the Community Justice Advisor (CJA) programme. As the CSAE's evaluation of the CJA programme unfolded, many dynamics associated with theoretical liberal-local hybridity surfaced; however, it also became apparent that this theoretical formulation obscured important dimensions which were reshaping what peacebuilding practice is in the process of becoming in the emerging post-liberal world.
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Modélisation de l'hétérogénéité de croissance dans le système aquacole / Modelling growth heterogeneity in the fish raring systemCampeas, Arnaud 04 March 2008 (has links)
L’hétérogénéité de croissance est un problème récurrent en aquaculture dont le déterminisme est le résultat d’une interaction complexe de nombreux facteurs: alimentaires, populationnels, environnementaux et génétiques. Nous avons développé un modèle individu-centré (système multi-agent) pour reproduire in silico les phénomènes biologiques sous-jacents (Mo.B.I.Fish : Model of Behavioral Interaction of Fish). La première étape a consisté en l’élaboration d’un modèle de croissance capable de modéliser la prise de poids d’un poisson en fonction de son ingéré. Deux types de modèles ont été évalués (Scope For Growth et Dynamic Energy Budget) sur des données expérimentales de croissance et le SFG a été retenu. Il a ensuite été utilisé en validation pour évaluer l’importance de l’ingéré et d’autres facteurs dans l’hétérogénéité de croissance. La deuxième étape de modélisation a consisté en l’élaboration d’un modèle simulant les interactions sociales entre poissons. Ces interactions ont été simulées par un système multi agents qui reproduit des séries de combats entre deux individus dont l’issue est dépendante de leur poids, de leurs interactions passées, de leur génétique et d’un effet aléatoire. Le résultat de ces combats influence leur nourrissage individuel. A l’aide de 2 expérimentations ad hoc de croissance de perche en circuit fermé, nous avons pu calibrer et valider le modèle de façon à estimer l’importance des différents facteurs dans le déterminisme des combats. La comparaison entre le modèle et les données a été faite sur les variables « poids moyen »« coefficient de variation » et « coefficient de corrélation de Spearman ». Il est apparu ainsi que la taille avait une faible importance, et que le déterminisme des combats pouvait être, en première approche considéré comme purement aléatoire. L’effet mémoire permet de simuler le désordre des rangs de poids des poissons entre le début et la fin de la période de croissance / Growth heterogeneity is a recurrent problem in fish aquaculture. Its determinism is the result of complex interactions between numerous factors: feeding rate, social interactions, environmental conditions and genetics. We developed an individualized based model (multi-agent system) to reproduce in silico biological phenomena (Mo.B.I.Fish : Model of Behavioral Interaction of Fish). The first step of modelling consisted of choosing a model that could simulate growth knowing the food intake. Two models were compared (Scope For Growth and Dynamic Energy Budget) to experimental data of growing fish: we finally chose the SFG. This model was used in validation to evaluate the relative influence of the food intake (combined with other factors) on growth heterogeneity. The second step of modelling consisted of building a model which simulated social interactions between fish. These interactions were simulated with a multi-agent system that reproduced fights between two fish, in which the final result depended on the weight, experience of each fish, genetic and random effect. The result of the fight had direct influence on the individual intake. Two experiments were conducted on perch in recirculating system, which provided to us data to both calibrate and validate the model. The output of the model was the mean weight, the coefficient of variation of the weight and the Spearman's rank correlation coefficient of fish weight. Hence we could estimate the relative importance of each factor in the determinism of the fights. We observed that size had little or no effect, and that the determinism could be considered as completely random. The experience effect also allowed simulating accurately the rank of the weight of fish between the beginning and the end of the experiments
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LOOKING TO THE FUTURE OF STROKE TREATMENT: COMBINING RECANALIZATION AND NEUROPROTECTION IN ACUTE ISCHEMIC STROKEManiskas, Michael E. 01 January 2016 (has links)
Stroke is the 5th leading cause of death in the U.S. with 130,000 deaths and around 800,000 affected annually. Currently, there is a significant disconnect between basic stroke research and clinical stroke therapeutic needs. Few animal models of stroke target the large vessels that produce cortical deficits seen in the clinical setting. Also, current routes of drug administration, intraperitoneal and intravenous, do not mimic the clinical route of intra-arterial drug administration. To bridge this divide, we have retro-engineered a mouse model of stroke from the current standard of care for emergent large vessel occlusion (ELVO) stroke, endovascular thrombectomy, to include selective intra-arterial pharmacotherapy administration. Using the tandem transient common carotid and middle cerebral artery occlusion (MCAo) model to induce stroke, we threaded micro-angio tubing into the external carotid artery (ECA) towards the bifurcation of the common carotid and internal carotid arteries (CCA/ICA) allowing for the delivery of agents to the site of acute ischemia. Our model was optimized through a flow rate and injection volume study using carbon black ink injected through the intra-arterial model at different flow rates and injection volumes. The purpose of this study was to demonstrate that our injections were arriving at the site of ischemia and to improve injection volumes for future dosing while mitigating systemic side effects by preventing or minimizing systemic distribution. We determined that a flow rate of 2.5 µl/minute and injection volume of 10 µl was optimal. Next, we tested potential neuroprotective compounds nitroglycerin, verapamil, and a combination of verapamil and lubeluzole. Compounds were chosen for drug synergy and to target specific pathways in either an acute or delayed manner. Acute treatments included nitroglycerin and/or verapamil while delayed treatment included lubeluzole. The known mechanism of action for FDA approved nitroglycerin is through vessel dilation that results in increased blood flow to the treated region. A secondary mechanism of nitroglycerin is the production of nitric oxide, which has demonstrated antioxidant and anti-apoptotic effects when processed and released from cells surrounding the blood vessels. Verapamil, a calcium channel blocker, also FDA-approved for cerebral artery vasospasm: is thought to act by blocking the L-type calcium channels on the cell membrane from opening following membrane depolarization after insult. Finally, lubeluzole, also FDA-approved, is proposed to work as an NMDA modulator inhibiting the release of glutamate and nitric oxide synthase and blocking sodium and calcium channels. Through our stroke model we were able to demonstrate that each drug(s) showed a significant decrease in infarct volume and improved functional recovery while simultaneously minimizing potential systemic side effects suggesting that our stroke model may improve the preclinical validation of potential stroke therapies and help bridge the bench to bedside divide in developing new stroke therapies.
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Enfoque integrado de la acción de compuestos farmaceuticos en peces teleósteos : efecto sobre la diferenciación sexual y la proliferación cerebral / Approche intégrée de l'action des composés pharmaceutiques chez les poissons téléostéens : effets sur la différentiation sexuelle et la prolifération cérébrale / An integrated approach to action of human pharmaceuticals in teleost fish : effects on the sexual differentiation and brain cell proliferationPérez, María Rita 16 December 2013 (has links)
Les effets négatifs des produits pharmaceutiques (PPs) sur les écosystèmes aquatiques est une préoccupation de plus en plus sensible. Nous avons analysé les effets du 17α-éthinylestradiol (EE2), composant des pilules contraceptives, et de la fluoxétine (FLX), l'antidépresseur le plus vendu au monde, sur deux poissons. Le pejerrey (Odontesthes bonariensis) vit dans des lagunes qui sont des réservoirs d'eaux usées, où la présence d'EE2 est détectée. En utilisant l'expression des gènes cyp19a1b (aromatase cérébrale) et cyp19a1a (aromatase gonadique) comment marqueurs biologiques nous avons constaté que l'exposition à EE2 n'affectait pas l'expression du gène cyp19a1b. Cependant, augmente significativement l'expression du cyp19a1a, liée à la différenciation ovarienne, et diminue l'expression de hsd11b2, liée a la différenciation testiculaire, chez les larves et mâles juvéniles. Aussi, produit une déviation des ratios male/femelles en faveur des femelles chez les larves et l'apparition de caractéristiques typique du développement ovarien dans les testicules de mâles juvéniles. Chez le poisson zèbre (Danio rerio) nous avons évalué le rôle de la sérotonine (5-HT) comme modulateur de la prolifération; et l'effet de la FLX, inhibiteur sélectif de sa recapture. Tout d'abord, nous avons montré que les neurones sérotoninergiques de l'hypothalamus sont générés à partir de cellules gliales radiaires présente dans cette région. Ensuite, nous avons constaté une réduction significative du nombre de cellules en prolifération dans le noyau du recessus lateral (NRL) et posterior (NRP) de l'hypothalamus, après de l'inhibition de la synthèse de 5-HT ; et dans le NRL, après d'exposition a FLX. / Over the last 10-15 years risks of pharmaceuticals and personal care products (PPCPs) in the environment have acquired significant relevance. In the present work we studied the effects of 17α-ethinylestradiol (EE2), component of contraceptive pills, and fluoxetine (FLX), the world’s most widely prescribed antidepressant, in fishes. Pejerrey (Odontesthes bonariensis) a south American teleost fish that inhabit aquatic ecosystems where EE2 has been reported. Exposure to EE2 did not alter the expression of cyp19a1b (brain aromatase). In contrast, expression of cyp19a1a (gonadal aromatase), involved in ovarian differentiation, was up-regulated; while expression of hsd11b2, associated with testicular differentiation, was down-regulated in larvae or juvenile males. Also, EE2 was able to shift sex ratios toward the female in larvae and alter the gonadal morphology of testicles of juvenile males. In zebrafish, a model organism considered as a useful tool in EDs screening, we investigated the potential role of serotonin (5-HT) as modulators of brain cell proliferation; in particular, we also analyzed the effects of FLX, a selective 5-HT reuptake inhibitor. We showed that 5-HT neurons of the hypothalamus originate from proliferative radial glial cells presents in this area. Treatment 5-HT synthesis inhibitor and exposure to environmentally relevant concentrations of FLX caused a significant decrease in the number of proliferating cells in the hypothalamus, resulting in a further decline in the number of own 5-HT neurons. These results provide evidence for the detrimental effect in teleost fish induced by the exposure to two pharmaceuticals considered as endocrine disruptors.
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