Angesichts der pluralen und heterogenen Angebotslandschaft intergenerationalen Lernens fragt diese Dissertation, über welche pädagogischen Handlungen, Interaktionen und Steuerungseinflüsse sich intergenerationale Lernkulturen konstituieren, vor dem Hintergrund welcher gesellschaftlicher Tendenzen bestimmte Handlungen und Steuerungseinflüsse relevant werden und welche Ausdrucksformen von intergenerationaler Erwachsenenbildung dabei entstehen. Im theoretischen Pfeiler widmet sich diese Arbeit dem intergenerationalen Lernen auf mehreren Ebenen. Aufgrund der bestehenden Vielfalt und Komplexität an begrifflichen Rahmungen, gesellschaftlichen Hintergrundentwicklungen sowie theoretischen Konstruktionen werden intergenerationale Lernkulturen auf einer begrifflichen, gesellschaftswissenschaftlichen, theoretisch konstituierenden und institutionell systematisierenden Ebene beschrieben und definiert. Auf der Basis der dort vorgenommenen begrifflichen Abgrenzungen und Systematisierungen kann der Begriff sowie die Erscheinungsformen intergenerationaler Lernkulturen eingegrenzt und weitergehend empirisch untersucht werden. Dazu wird im empirischen Pfeiler der Arbeit eine zweistufige triangulative Explorationsstudie angesetzt, die durch eine Programmanalyse und Experteninterviews gekennzeichnet ist. Das Untersuchungsfeld verortet sich dabei auf der Mesoebene erwachsenendidaktischen Handelns und ist durch Interferenzen zwischen der makro- und mesodidaktischen Handlungs- und Interaktionsebene (Zeuner, 2009) gekennzeichnet. Aus den Befunden der Untersuchung lässt sich schlussfolgern, dass dichotome Adressat/-innenbeschreibungen, Begegnungs- anstatt Lernprozesse und wirtschaftliche anstatt pädagogische Orientierungen bei den Programmplanenden intergenerationaler Programme handlungsleitend für ihre Planungsarbeit sind. Es zeigt sich darüber hinaus, dass intergenerationale Lernkulturen einen sehr geringen Professionalisierungsgrad aufweisen und dass der gesellschaftliche Bedarf intergenerationalen Lernens in symbolischen Generationenbeziehungen instrumentalisiert wird. Die Relevanz der Studie liegt damit insbesondere in einem bildungswissenschaftlichen Beitrag zu einer Generationentheorie für die Erwachsenenbildung, einer theoretischen Konturierung des Intergenerationalitätkonzepts, unter Bezug auf eine erwachsenenpädagogische Generationentheorie, einem Beitrag zur Programm- und Planungsforschung sowie in dem empirischen perspektivverschränkenden Beitrag zur Professionalisierungsforschung innerhalb beigeordneter Bildungsangebote. / Seeing the diverse and plural programs in the field of intergenerational learning, it is interesting to find out about the pedagogical and didactic actions and interactions as well as the influences of governance and regulation in intergenerational learning cultures. In the theoretical part of this thesis intergenerational learning is described and defined on the level of conceptual and socioscientific approaches, theoretical constitutions and institutional systematisation. Based on the proposed conceptual differentiations, the empirical investigations will elucidate the field of intergenerational learning. As a result the empirical work focuses on a triangulative study combining a program analysis with theory generating expert interviews. The case of study is positioned in the mesodidactic level and is characterised by interferences between makro- and mesodidactic level of action and interaction (Zeuner, 2009). The theoretical and empirical findings present patterns of intergenerational learning cultures that show an unspecific and dichotomous description of the intended audience. The findings also show that typically intergenerational encounters are more prominent than intended and critically reflected learning processes. Moreover, economic interests overbalance pedagogical interest. Consequently, intergenerational learning is interpreted as a rather low professionalised exploited field of continuing education, where generational encounters are supposed to be pedagogical.

<p>Ispitivan je uticaj vrednosti procesnih parametara: na tehnolo&scaron;ku efikasnost procesa osmotske dehidratacije pilećeg mesa u vodenom rastvoru NaCl i saharoze i melasi; na nivo redukcije odabranih mikroorganizama (Escherichia coli, Salmonella spp., Listeria monocytogenes) u osmotskim rastvorima; na mikroorganizme prisutne na dehidrirajućem pilećem mesu; istraživana je podobnost osmotski dehidriranog pilećeg mesa za rast i razmnožavanje odabranih mikroorganizama tokom perioda skladi&scaron;tenja, uz definisanje zdravstveno bezbednog roka skladi&scaron;tenja na osnovu mikrobiolo&scaron;kih i hemijskih analiza.<br />Rezultati ispitivanja pokazuju da povećanje vrednosti procesnih parametara temperature, vremena trajanja procesa i koncentracije osmotskih rastvora dovodi do intenziviranja prenosa mase između dehidrirajućeg materijala i rastvora i povećanja efikasnosti procesa. Izlaganjem odabranih mikroorganizma osmotskim rastvorima postignuti su visoki nivoi njihove redukcije. U melasi postignuti su vi&scaron;i nivou redukcije mikroorganizama u poređenju sa vodenim rastvorom. Ostvareni nivoi redukcije odabranih mikroorganizama na pilećem mesu tokom procesa niži su u poređenju sa rezultatima redukcionih odnosa istih mikroorganizama direkno inokulisanih u istim osmotskim rastvorima. Sa protokom vremena skladi&scaron;tenja ve&scaron;tački kontaminiranog i osmotski dehidriranog pilećeg mesa, u oba osmotska rastvora, do&scaron;lo je do smanjenja broja svih ispitivanih mikroorganizama. Proteolitički mikroorganizami nisu bili prisutni u dehidranom pilećem mesu, dok sadržaj histamina je pokazao da, tokom vremena skladi&scaron;tenja, nije dolazilo do degradacije proteina u mesu. Nakon 10 dana skladi&scaron;tenja meso nije bilo užeglo, a vrednosti malondialdehida su ukazale na pojavu užegnuća nakon 14 dana skladi&scaron;tenja.<br />Na osnovu dobijenih rezultata razvijeni su modeli zavisnosti odziva procesa osmotske dehidratacije, nivoa redukcije ispitivanih mikroorganizama u osmotskim rastvorima, nivoa redukcije ispitivanih mikroorganizama na dehidriranom pilećem mesu i mikrobiolo&scaron;kih i hemijskih odziva dehidriranog pilećeg mesa tokom skladi&scaron;tenja u zavisnosti od variranih vrednosti parametara procesa.<br />Na osnovu dobijenih rezultata, kao optimalni parametri, mogu da se defini&scaron;u: trajanje procesa od 5 časova, temperatura od 32&deg;C u melasi, kao osmotskom rastvoru, maksimalne koncentracije. Svi postignuti nivoi redukcije mikroorganizama ukazuju na dobru osnovu za proizvodnju zdravstveno bezbednih proizvoda od pilećeg mesa. Analiza održivosti je pokazala da je osmotski dehidriranom pileće meso mikrobiolo&scaron;ki i hemijski stabilno tokom skladi&scaron;tenja na temperaturi od 22 &deg;C u trajanju od najmanje 10 dana.</p> / <p>The effect of process parameters values on: technological efficiency of chicken meat osmotic dehydration process in water solution of NaCl and succrose and molasses; selected microorganisms (Escherichia coli, Salmonella spp., Listeria monocytogenes) in osmotic solutions reduction levels; selected microorganisms on dehydrating chicken meat reduction levels, is investigated. The osmodehydrated chicken meat suitability for selected microorganisms&rsquo; growth and multiplication during storage period is also investigated, together with defining health safe storage period, on the basis of microbiological and chemical analysis.<br />Results shows that increase of process parameters of temperature, duration and osmotic solutions&rsquo; concentrations leads to mass transfer increase between dehydrating material and osmotic solutions and process efficiency increase. Exposure of selected microorganisms to osmotic solution has led to high levels of reductions of their numbers. Processes in molasses had higher levels of microorganisms&rsquo; reductions in comparison to the water solution. Achieved levels of the selected microorganisms&rsquo; on chicken meat reductions were lower in comparison to the results of reduction of the same microorganisms directly inoculated in the same osmotic solutions. With the increase of the inocualted, osmotically dehydrated chicken meat storage time in both osmotic solutions, decrease of all tested microorganisms occured. Proteolytic microorganisms were not detected in dehydrated chiken meat, while histamin content showed that, during storage, there was no meat protein degradation. After 10 days of storage, meat was not rancid, while malondialdehid values showed that lipid oxidation occured after 14 days of storage. On the basis of obtained results, mathematical models of dependance of: osmotic dehydration process responces; selected micororganisms in osmotic solutions reduction levels; selected microorganisms on osmodehydrated chicken meat reduction levels; and osmodehydrated chicken meat during storage microbiological and chemical responces; from varied process parameters, were developed.<br />Based on obtained results, as optimal process parameters it can be defined: 5-hour process, at 32 &deg;C, in molasses of maximal concentration, as osmotic solution. All achived microorganisms&rsquo; reduction levels can indicate on good basis of health safe chicken meat production. Analysis of storage duration has shown that osmotdehydrated chicken meat is microbilogicaly and chemicaly stabile during sotrage at 22 &deg;C in period of at least 10 days.</p>

This paper reports a numerical approach for modelling the thermal behavior and heat accumulation/liberation of sustainable cementitious composites made with Recycled Brick Aggregates (RBAs) employed as carriers for Phase-Change Materials (PCMs). In the framework of the further development of the fixed grid modelling method, classically employed for solving the well-known Stefan problem, an enthalpy-based approach and an apparent calorific capacity method have been proposed and validated. More specifically, the results of an experimental program, following an advanced incorporation and immobilization technique, developed at the Institut für Werkstoffe im Bauwesen for investigating the thermal responses of various combinations of PCM-RBAs, have been considered as the benchmark to calibrate/validate the numerical results. Promising numerical results have been obtained, and temperature simulations showed good agreement with the experimental data of the analyzed mixtures.

Drawing on the notion of faultlines – a hypothetical dividing line that splits a group into two or more subgroups based on the alignment of one or more individual attributes – this thesis proposes a new approach to the measurement and assessment of board diversity to understand how high(er) performing boards can be built i.e., the multi-dimensional diversity index (MDI). The proposed MDI captures the joint effect of differences in director attributes at four diversity levels for 26,743 directors, namely: (i) surface (or baseline); (ii) identity; (iii) demographic; and (iv) meso-level. The current study uses three-stage least squares (3SLS) with a panel of 3,357 FTSE All-Share index non-financial companies from 2005 to 2018. To this end, a key implication of this study – and by extension, the proposed MDI – is that it challenges the conventional notion that boards are improved ‘enough’ by focusing on the micro-dimension and increasing stand-alone diversity attributes, such as gender. Collectively, this study’s results suggest that a well-diversified board incentivises managers to disclose more information on social and environmental activities in contrast to firms with an extreme faultline score. The results show that highly effective boards with a moderate faultline score at meso-level diversity (e.g., identity, information, and non-demographic attributes) lead to better accounting profitability, corporate value, and market-based performance. Remarkably, the present study finds that nationality diversity per se positively impacts corporate performance; in contrast, the dominance of male directors hinders firm performance significantly.

No description available.

Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2019-03-25T16:13:20Z No. of bitstreams: 1 Tatiani_Bianco_2018.pdf: 5463183 bytes, checksum: 623edce81df00dd24349d6ce63dfc11f (MD5) / Made available in DSpace on 2019-03-25T16:13:20Z (GMT). No. of bitstreams: 1 Tatiani_Bianco_2018.pdf: 5463183 bytes, checksum: 623edce81df00dd24349d6ce63dfc11f (MD5) Previous issue date: 2018-11-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The problem of urban solid waste management (RSU) is a topic of worldwide concern, and has been treated as a priority, since equating excessive generation and final disposal of environmentally sound waste is one of the major challenges facing modern society. Thus, the RSUs are correctly managed as a challenge / goal to be achieved, in order to minimize the negative impacts caused by the generation of waste from various generating sources. In view of the above, this thesis aimed to propose a model of MSW management differentiated, in the stages of collection, transportation, treatment and recovery of waste, capable of meeting the legal prerogatives in economic, social and environmental context, and that allows the implantation of an economic model that generates wealth, employment and income in a sustainable environment in the municipalities of the Western Mesoregion of Paraná. For that, the methodological procedures included the execution of six stages, namely: 1) Characterization of the sources of RSU in the western mesoregion of Paraná; 2) Estimation of the potential of RSU generation in the municipalities of the Western Mesoregion of Paraná, during the years 1980 to 2030; 3) Evaluation of the execution of the National Solid Waste Policy as of the enactment of Federal Law No. 12,3052010; 4) Prospecting of methods, processes and technologies for the collection, transport, treatment and use of MSW; 5) Presentation of the MSW management model that allows the consolidation of an economic and sustainable system based on the MSW industrialization based on the economic, social and environmental specificities of the municipalities of the West of Paraná; 6) Consolidation and systematization of results. The results showed that only 12% of the municipalities of the Western Mesoregion of Paraná presented, through the construction of the Indicator of Sustainable Regional Development, a dynamic relationship in their productive base with economic, social and environmental advances. However, given the potential increase in the generation capacity of the MSW in the region, which was estimated at around 41%, it was identified that the 50 municipalities had a daily solid waste generation potential of 595.6 ton/day, in 1980, to 841.5 ton/day, in 2030. Thus, it was evidenced that there is inability to comply with Federal Law No. 12.305/2010, where 63% of the municipalities of the West of Paraná do not have the capacity economic, financial and technical / intellectual staff capable of handling the costs of managing and maintaining the correct level of waste management. This result is mainly due to the application of PNRS guidelines and targets in the municipalities of the West of Paraná through individualized solutions (landfills and / or controlled landfills), which become sources of economic and financial problems for the municipal administrations, as well as in the unfeasible possibility of meeting all the determinations in effect in PNRS / 2010. This scenario also occurs when one intends to establish only one intermunicipal waste management consortium capable of serving the 50 municipalities in the region, since a total investment of R $ 936.28 million would be necessary considering the amount of waste generated in the region, by 2030. Thus, the feasible, economical, social and environmentally adequate solution to waste management in the municipalities of the West of Paraná is the use of three Integrated Systems of Solid Urban Waste Management (SIGRSU), which should be implanted in the Microregions of Cascavel, Foz do Iguaçu and Toledo. Thus, the implementation of this new MSW management model, based on differentiated methods and technologies, has demonstrated the technical and economic viability of the proposal, in which urban solid waste becomes a cost factor and becomes an investment opportunity. In this scenario, the economic variable is one of the main attractions for individuals, while the impacts on the environment and society are also positive. Therefore, there is an environmental externality transformed into a source of opportunities for new business models, in which waste is considered as raw material and / or input of industrial processes, which will help in the sustainable and innovative development of the Meso-region under study, since it would be capable of generating income, from the implementation and development of new technologies, increase the useful life and reduce the need to increase the area for landfills and, thus, make the municipalities comply with the guidelines of Federal Law N ° 12.305/2010, of the PNRS. / O problema do gerenciamento de Resíduos Sólidos Urbanos (RSU) é tema de interesse mundial, e tem sido tratado como prioritário, uma vez que, equacionar a geração excessiva e disposição final e ambientalmente segura dos resíduos é um dos maiores desafios com que se defronta a sociedade moderna. Assim, denota-se a gestão correta dos RSUs como desafio/meta a ser alcançado, visando minimizar os impactos negativos causados pela geração dos resíduos de diversas fontes geradoras. Diante do exposto, a presente tese objetivou propor um modelo de gestão de RSU diferenciado, nas etapas de coleta, transporte, tratamento e aproveitamento de resíduos, capaz de atender as prerrogativas legais em âmbito econômico, social e ambiental, e, que possibilite a implantação de um modelo econômico gerador de riqueza, emprego e renda num ambiente sustentável nos municípios da Mesorregião Oeste do Paraná. Para tanto, os procedimentos metodológicos contemplaram a execução de seis etapas, sendo estas: 1) Caracterização das fontes geradoras de RSU na mesorregião Oeste do Paraná; 2) Estimação do potencial de geração dos RSU nos municípios da Mesorregião Oeste do Paraná, durante os anos de 1980 a 2030; 3) Avaliação da execuçãoimplantação da Política Nacional dos Resíduos Sólidos a partir da promulgação da Lei Federal N°12.3052010; 4) Prospecção dos métodos, processos e tecnologias para a coleta, transporte, tratamento e aproveitamento de RSU; 5) Apresentação do modelo de gestão de RSU diferenciado, que possibilite a consolidação de um sistema econômico e sustentável com base da industrialização dos RSU a partir das especificidades econômicas, sociais e ambientais dos municípios da Mesorregião Oeste do Paraná; 6) Consolidação e sistematização dos resultados. Os resultados demonstraram que apenas 12% dos municípios da Mesorregião Oeste do Paraná apresentaram, por meio da construção do Indicador de Desenvolvimento Regional Sustentável, dinâmica relação na sua base produtiva com avanços econômicos, sociais e ambientais. Contudo, dado o aumento potencial da capacidade de geração de RSU na região, que foi estimado na ordem de 41%, identificou-se que, os 50 municipios apresentaram um potencial de geração de RSU de um montante diário de 595,6 ton.dia, em 1980, para 841,5 ton.dia, em 2030. Assim, evidenciou-se que, há incapacidade no atendimento da Lei Federal N°12.305/2010, onde 63% dos municípios do Oeste do Paraná, não apresentam capacidade econômica, financeira e de corpo técnico/intelectual capaz de arcar com os custos de gestão e manutenção do correto nível de gerenciamento dos resíduos gerados. Tal resultado, deve-se, em maior parte dada a aplicação das diretrizes e metas da PNRS nos municípios do Oeste do Paraná por meio de soluções individualizadas (aterros sanitários e/ou controlados), as quais se transformam em fontes de problemas econômico-financeiros para as gestões municipais, bem como na inviável possibilidade de atendimento de todas as determinações vigentes na PNRS/2010. Tal cenário também se verifica quando se tem a intenção de implantar apenas um consórcio intermunicipal de gerenciamento de resíduos, capaz de atender aos 50 municípios da região, pois seria necessário um investimento total de R$936,28 milhões de reais, considerando o montante de resíduos gerados na região, até 2030. Assim, a solução viável, econômico, social e ambientalmente adequada a gestão de resíduos nos municípios do Oeste do Paraná é a utilização de três Sistemas de Gerenciamento Integrado de Resíduos Sólidos Urbanos (SIGRSU), os quais devem ser implantados nas Microrregiões de Cascavel, Foz do Iguaçu e Toledo. Assim, a implementação desse novo modelo de gestão dos RSU, baseado em métodos e tecnologias diferenciadas, demonstraram a viabilidade técnica e econômica da proposta, na qual os resíduos sólidos urbanos passam de um fator de custo e se tornam uma oportunidade de investimento. Nesse cenário, a variável econômica é um dos maiores atrativos para os indivíduos, ao mesmo tempo em que os impactos no meio ambiente e na sociedade são também positivos. Portanto, tem-se uma externalidade ambiental transformada em fonte de oportunidades de novos modelos de negócios, no qual os resíduos são considerados matérias-primas e/ou insumos de processos industriais, qual auxiliará no desenvolvimento sustentável e inovador da Mesorregião em estudo, pois seria capaz de gerar renda, a partir da implementação e desenvolvimento de novas tecnologias, aumento da vida útil e redução da necessidade de aumento de área para aterros sanitários e, assim, fazer com que os municípios ficassem em conformidade com as diretrizes da Lei Federal N° 12.305/2010, do PNRS.

This work presents a systematic study of the mechanochemical processes leading to chemical reactions occurring due to effects of high-strain-rate deformation associated with uniaxial strain and uniaxial stress impact loading in highly heterogeneous metal powder-based reactive materials, specifically compacted mixtures of Ti/Al/B powders. This system was selected because of the large exothermic heat of reaction in the Ti+2B reaction, which can support the subsequent Al-combustion reaction. The unique deformation state achievable by such high-pressure loading methods can drive chemical reactions, mediated by microstructure-dependent meso-scale phenomena. Design of the next generation of multifunctional energetic structural materials (MESMs) consisting of metal-metal mixtures requires an understanding of the mechanochemical processes leading to chemical reactions under dynamic loading to properly engineer the materials. The highly heterogeneous and hierarchical microstructures inherent in compacted powder mixtures further complicate understanding of the mechanochemical origins of shock-induced reaction events due to the disparate length and time scales involved. A two-pronged approach is taken where impact experiments in both the uniaxial stress (rod-on-anvil Taylor impact experiments) and uniaxial strain (instrumented parallel-plate gas-gun experiments) load configurations are performed in conjunction with highly-resolved microstructure-based simulations replicating the experimental setup. The simulations capture the bulk response of the powder to the loading, and provide a look at the meso-scale deformation features observed under conditions of uniaxial stress or strain. Experiments under uniaxial stress loading reveal an optimal stoichiometry for Ti+2B mixtures containing up to 50% Al by volume, based on a reduced impact velocity threshold required for impact-induced reaction initiation as evidenced by observation of light emission. Uniaxial strain experiments on the Ti+2B binary mixture show possible expanded states in the powder at pressures greater than 6 GPa, consistent with the Ballotechnic hypothesis for shock-induced chemical reactions. Rise-time dispersive signatures are consistently observed under uniaxial strain loading, indicating complex compaction phenomena, which are reproducible by the meso-scale simulations. The simulations show the prevalence of shear banding and particle agglomeration in the uniaxial stress case, providing a possible rationale for the lower observed reaction threshold. Bulk shock response is captured by the uniaxial strain meso-scale simulations and is compared with PVDF stress gauge and VISAR traces to validate the simulation scheme. The simulations also reveal the meso-mechanical origins of the wave dispersion experimentally recorded by PVDF stress gauges.

Que signifie "économie de marché socialiste" (EMS)? Quels sont les changements concrets de la planification vers cette EMS? Quel est l'impact de ces changements sur un secteur industriel donné tel que le secteur automobile? Sur les danweis de production? Telles sont les questions que nous voulons étudier dans cette thèse. Notre démarche est empirique. Nous partons d'abord de nos premières observations et des nombreux entretiens sur le terrain. Notre démarche est ensuite systémique et institutionnelle car les réformes, en modifiant les règles du jeu, ont un impact sur l'organisation et la structure de l'industrie et des danweis. Nous soulignons l'évolution des réseaux de production socialiste vers des secteurs industriels différenciés qui restent marqués par leur passé socialiste, comme le secteur automobile. Les travaux sur ce sujet sont encore peu nombreux. Nous utilisons les outils de l'économie industrielle pour analyser les particularités de l'industrie automobile Chinoise et les comparer à celles de l'industrie automobile dans l'économie de marché capitaliste. Les résultats de notre recherche sont les suivants: Dans le courant de pensée économique dominant, l'idée de "socialisme de marché" est associée à l'idée d'un système de marché qui éviterait les problèmes de répartition inégale de richesse liée aux droits de propriété privée. Mais en réalité le cas Chinois nous montre plutôt une coexistence de deux systèmes parallèles qu'une compatibilité entre socialisme et marché. Ainsi, parallèlement à un système socialiste qui perdure, on assiste à un recul du pouvoir politique et de l'administration, à une plus grande indépendance de la législation vis-à-vis du Parti, et à la mise en place progressive de mécanismes de marché. Au niveau de l'industrie, les réformes tentent de transformer en secteurs industriels les réseaux de production socialistes cloisonnés verticalement et horizontalement issus de la planification socialiste. Pour transformer les danweis multi-fonctionnelles, les réformes tâtonnent par expérimentation de différentes méthodes de gestion, les rendent "responsables économiquement", tout en gardant intact le système de droit de propriété publique (idéologie socialiste).

Plusieurs études à grande échelle ont identifié la modification ou la perte d’habitats comme menace principale à la conservation des communautés de poissons d’eau douce. Au Canada, « aucune perte nette dans la capacité productive des habitats » (NNL) est le principe directeur de la politique de gestion des habitats du ministère des Pêches et Océans. Le respect du NNL implique l’avancement des connaissances au niveau des relations entre les poissons et leurs habitats, de même que des outils pour quantifier l’impact de la modification des habitats sur les poissons. Les modèles d’utilisation de l’habitat des poissons (FHUM) sont des outils qui permettent d’améliorer nos connaissances des relations poissons – habitat, de prédire la distribution des espèces, mais aussi leurs densités, biomasses ou abondances, sur la base des caractéristiques de l’environnement. L’objectif général de mon mémoire est d’améliorer la performance des FHUM pour les rivières des basses Laurentides, en suggérant des perfectionnements au niveau de 2 aspects cruciaux de l’élaboration de tels modèles : la description précise de la communauté de poissons et l’utilisation de modèles statistiques efficaces. Dans un premier chapitre, j’évalue la performance relative de la pêcheuse électrique et de l’échantillonnage en visuel (plongée de surface) pour estimer les abondances des combinaisons d’espèces et de classes de taille des poissons en rivière. J’évalue aussi l’effet des conditions environnementales sur les différences potentielles entre les communautés observées par ces 2 méthodes d’échantillonnage. Pour ce faire, 10 sections de rivière de 20 m de longueur ont été échantillonnées à l’aide de ces 2 méthodes alors qu’elles étaient fermées par des filets de blocage. 3 plongeurs performèrent l’échantillonnage en visuel en se déplaçant de l’aval vers l’amont des sections, tout en dénombrant les espèces et classes de taille. Par la suite, nous avons fait 3 passages de pêcheuse électrique et les abondances furent estimées grâce à un modèle restreint de maximum de vraisemblance, basé sur la diminution des abondances observées. De plus grandes abondances de poissons furent observées en visuel qu’avec la pêcheuse électrique à tous les sites. La richesse spécifique observée en visuel était plus élevée (6/10) ou égale (4/10) à celle observée avec la pêcheuse électrique. Les différences entre les communautés de poissons observées à l’aide de ces 2 méthodes ne purent être reliées aux conditions environnementales. Les résultats de cette expérience sont contraires à ceux de toutes les études comparant ces 2 méthodes d’échantillonnage, lesquels suggèrent une supériorité de la pêcheuse électrique. Les conditions environnementales de notre expérience étaient distinctes de celles observées dans les autres études (absence d’arbres tombés dans l’eau, très peu de substrats grossiers), mais la différence la plus marquante était en terme de communauté de poissons observée (dominance des cyprinidés et des centrarchidés plutôt que des salmonidés). Je termine ce chapitre en suggérant que les caractéristiques comportementales favorisant l’évitement de la capture (formation de bancs) et facilitant l’observation en visuel (curiosité) sont responsables de la supériorité de la plongée de surface pour échantillonner les communautés dans les rivières des basses Laurentides. Dans un deuxième chapitre, je développe des FHUM pour des communautés de poissons de rivière ayant plusieurs espèces. Dans le but de simplifier la modélisation de telles communautés et d’améliorer notre compréhension des relations poissons – habitat, j’utilise les concepts de guilde écologique et de filtre environnemental pour explorer les relations entre les guildes formées sur la bases de différents types de traits (reproducteurs, taxonomiques, éco-morphologiques et alimentaires) et les conditions environnementales locales à l’échelle du méso-habitat. Les modèles d’habitats basés sur les guildes reproductrices ont clairement surpassé les autres modèles, parce que l’habitat de fraie reflète l’habitat de préférence en dehors de la période de reproduction. J’ai également utilisé l’approche inverse, c’est à dire définir des guildes d’utilisation de l’habitat et les mettre en relation avec les traits des espèces. Les traits reliés à l’alimentation des poissons ont semblés être les meilleurs pour expliquer l’appartenance aux groupes d’utilisation de l’habitat, mais le modèle utilisé ne représentait pas bien la relation entre les groupes. La validation de notre modèle basé sur les guildes reproductrices avec un jeu de données indépendant pourrait confirmer notre découverte, laquelle représente une manière prometteuse de modéliser les relations poissons – environnement dans des communautés de poissons complexes. En conclusion, mon mémoire suggère d’importantes améliorations aux FHUM pour les communautés de poissons des basses Laurentides, en suggérant de prendre en compte les caractéristiques biologiques des cours d’eau dans le choix d’une méthode d’échantillonnage, et également en utilisant une méthode prometteuse pour simplifier les FHUM de communautés de poissons complexes : les guildes reproductrices. / Many large scale studies have identified habitat modification or habitat losses as primary threats for the conservation of freshwater fish communities. In Canada, No Net Loss (NNL) of the productive capacity of habitats is the guiding principle of the Department of Fisheries and Oceans’ policy for the management of fish habitat. To respect NNL, a better understanding of fish-habitat relationships is required, as well as tools to quantify the impact of habitat modifications on fish. Fish habitat use models (FHUM) are tools that can improve our understanding of fish-habitat relationships, predict species occurrences, densities or biomass on the basis of habitat descriptors and quantify habitat requirements. They consist in relationships between biological descriptors of fish and habitat descriptors. The general objective of my thesis is to improve the performance of FHUM for the lower Laurentian streams by suggesting refinements on 2 crucial aspects in the development of these models: a precise description of the fish community and the use of efficient statistical models. In the first chapter, I evaluate the relative performance of electrofishing and visual surveys (snorkeling) for estimating the abundance of combinations of fish species and size classes in rivers. I also assessed the effect of environmental conditions on potential differences between the results obtained using these two sampling methods. Sampling sites consisted in 10 river sections of 20 m in length distributed in the Laurentian region of Québec. Both methods were used while sections were blocked. Three snorkelers that swam the river sections upstream while identifying and counting fish of each species and size-classes performed visual surveys. Three-pass electrofishing was performed and abundances were estimated with a maximum likelihood depletion model. Greater abundances of fish were observed by snorkeling than by electrofishing at all sites. Snorkeling species richness was higher (6/10) or equal (4/10) to electrofishing richness. Differences in the fish communities observed by both sampling methods were not related to environmental conditions. The results of our work are therefore contrary to that of most published studies that suggested the superiority of electrofishing on visual surveys. Compared to the conditions found in previous studies, our sampling sites had different environmental characteristics (no fallen trees, insignificant cover of large cobble and boulder) but the most striking dissimilarity was in terms of fish communities (dominance of cyprinids and centrarchids instead of salmonids). Behavioural characteristics favouring capture avoidance (schooling) and facilitating underwater observation (curiosity) may be responsible for the superiority of visual surveys in our study rivers. Survey methods should be selected based on fish community composition. In the second chapter, I develop FHUM for complex stream fish communities. In order to simplify the modelling of such communities, as well as improve our understanding of fish – habitat relationships, I used the ecological guild concept and the niche filtering hypothesis to explore the relationships between guilds based on different types of traits (eco-morphological, reproductive, alimentary and taxonomic) and local environmental descriptors, at the coarse meso-habitat scale. Reproductive guilds led to FHUM that clearly outperformed the other 3 approaches, because of the close relationship between preferred spawning grounds and non spawning habitat preferences, and also because reproductive traits are linked to habitat characteristics at the reach or coarse mesohabitat scale. We also defined guilds based on habitat-use and related them to species traits. Traits related to the feeding biology of fishes seemed to be the best at explaining the habitat-use guilds, but our model did not correctly represent the among-guild relationships. Validation of our reproductive trait model on an independent dataset would confirm our finding, which represents a promising way of modelling fish - habitat relationships in complex fish communities. In conclusion, my thesis suggests important improvements to FHUM models in the Laurentian streams by giving new insights on the choice of a sampling method that take into account the biological characteristics of the streams targeted, and by using a promising way of simplifying FHUM for species rich communities: reproductive guilds.

Les matériaux méso-structurés sont des matériaux à porosité contrôlée, issus de synthèses de chimie sol/gel entre micelles de tensioactifs et précurseur inorganique, le plus souvent de silice. Parmi ces matériaux, le SBA-15, formé en milieu super-acide à partir de P123 (un copolymère tribloc) comme tensioactif et de TEOS comme précurseur inorganique de silice, est un des plus étudiés. La synthèse de ce matériau a été étudiée par diffusion des rayons X à petits angles (SAXS) in situ, et a permis de décrire qualitativement et quantitativement les mécanismes d’auto-assemblages entre micelles de tensioactifs et particules silicatées. Spécifiquement, nos résultats ont montré que l’hydrolyse-condensation du TEOS en solution a permis la formation d’oligomères de silice, qui interagissent avec la couronne des micelles sphériques de P123, pour progressivement former des micelles hybrides cylindriques organiques/inorganiques, qui vont ensuite précipiter en une mésophase hybride 2D-hexagonale. Ce modèle de synthèse est appelé « transition sphères-cylindres ». De plus, afin de comprendre les mécanismes de formation du matériau à toutes les échelles, nous avons étudié l’influence des conditions de synthèse sur la morphologie des grains de matériau méso-structurés. En effet, nous avons montré que sans agitation pendant la synthèse, les grains de matériaux présentent une forme d’équilibre qui dépend fortement de la température de synthèse. En fonction de la température, il est donc possible de former des matériaux hybrides de forme grains de riz, bâtons (courts ou longs) ou mêmes sous forme de tores. Nous proposons un modèle théorique qui permet d’expliquer l’ensemble des morphologies observées, en fonction des tensions de surfaces et des énergies de courbures de cristal-liquide 2D-hexagonal lors de la précipitation de la mésophase hybride. Nous appuyons ce modèle théorique sur des études en diffusion des rayons X à très petits angles (USAXS), qui permettent d’étudier la croissance des grains. Grâce à ces études, nous proposons une description très complète de la formation du matériau SBA-15. Fort de ces connaissances, nous avons pu, grâce à de nouvelles études de SAXS in situ, appliquer le modèle de précipitation de type « transition sphères-cylindres » à d’autres matériaux, issus de tensioactifs non-ioniques fluorés, et ainsi expliquer la formation de matériaux dits « bimodaux », c’est-à-dire issus d’un mélange entre P123 et un tensioactif fluoré(Rf₈(EO)₉ et qui présentent deux ordres poreux bien définis. Enfin, nous avons cherché à utiliser nos connaissances pour la fabrication de matériaux innovants, en remplaçant la solution micellaire par des émulsions dopées en nanoparticules d’or (NPs), afin de fabriquer des matériaux hybrides dopés en NPs. / Meso-structured materials are materials with a well-controlled porosity, designed from sol/gel syntheses between surfactant micelles and an inorganic precursor, most often a silica precursor. Among them, the SBA-15 material, formed in super-acid solution from P123 (a tri-block copolymer) as surfactant and TEOS a silica precursor, is one of the most studied. Synthesis of this material has been studied by in situ Small Angle X-Ray Scattering (SAXS), which allowed to describe both qualitatively and quantitatively the self-assembly mechanisms between surfactant micelles and silica particles. In details, our results showed that TEOS hydrolysis-condensation allow the formation of silica oligomers that interact with the corona of the spherical micelles of P123, and progressively the micelles reshape in hybrid organic/inorganic cylindrical micelles. The hybrid micelles, first free in solution, eventually precipitate in a hybrid 2D-hexagonal mesophase. This model of synthesis is called “sphere-to-rod transition”. Moreover, in order to understand the material mechanisms of formation at every length scales, we studied the influence of the synthesis conditions on the morphology of the meso-structured material grains. Indeed, in agreement with a previous study, our results show that if the synthesis is made without stirring, the material grains has an equilibrium shape that strongly depends on the synthesis temperature. By changing the temperature, one can form hybrid materials with a “rice grain” shape, or a (short or long) rod shape, or even a torus shape. We propose a theoretical model to explain all the observed morphologies, model that takes into account surface tensions and curvature energy of the newly formed 2D-hexagonal liquid-crystal at the precipitation of the hybrid mesophase. We measured the nucleation and growth of the grains by Ultra Small Angle X-Ray Scattering (USAXS). Thanks to all these studies, we present a complete description of the formation of the SBA-15 material. Our knowledge were used to describe new in situ SAXS measurements of new materials: our “sphere-to-rod transition” model was able to describe the formation of two materials, form two fluorinated surfactants and allowed to explain the formation of a “bimodal” material, which means a material with two well-defined porous order, that is synthesized from a mix of two surfactant (P123 and (Rf₈(EO)₉). Finally, we tried to use our knowledge to form innovative materials, by replacing the micellar solution as template by an emulsion doped in gold nanoparticles (NPs) to form hybrid materials doped in NPs.