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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

SpectroPolarimetric Imaging Observations

Bradley, Christine Lavella, Bradley, Christine Lavella January 2017 (has links)
The capability to map anthropogenic aerosol quantities and properties over land can provide significant insights for climate and environmental studies on global and regional scales. One of the primary challenges in aerosol information monitoring is separating two signals measured by downward-viewing airborne or spaceborne instruments: the light scattered from the aerosols and light reflected from the Earth's surface. In order to study the aerosols independently, the surface signal needs to be subtracted out from the measurements. Some observational modalities, such as multispectral and multiangle, do not provide enough information to uniquely define the Earth's directional reflectance properties for this task due to the high magnitude and inhomogeneity of albedo for land surface types. Polarization, however, can provide additional information to define surface reflection. To improve upon current measurement capabilities of aerosols over urban areas, Jet Propulsion Laboratory developed the Multiangle SpectroPolarimetric Imager (MSPI) that can accurately measure the Degree of Linear Polarization to 0.5%. In particular, data acquired by the ground-based prototype, GroundMSPI, is used for directional reflectance studies of outdoor surfaces in this dissertation. This work expands upon an existing model, the microfacet model, to characterize the polarized bidirectional reflectance distribution function (pBRDF) of surfaces and validate an assumption, the Spectral Invariance Hypothesis, on the surface pBRDF that is used in aerosol retrieval algorithms. The microfacet model is commonly used to represent the pBRDF of Earth's surface types, such as ocean and land. It represents a roughened surface comprised of randomly oriented facets that specularly reflect incoming light into the upward hemisphere. The analytic form of the pBRDF for this model assumes only a single reflection of light from the microfaceted surface. If the incoming illumination is unpolarized, as it is with natural light from the Sun, the reflected light is linearly polarized perpendicular to the plane that contains the illumination and view directions, the scattering plane. However, previous work has shown that manmade objects, such as asphalt and brick, show a polarization signature that differs from the single reflection microfacet model. Using the polarization ray-tracing (PRT) program POLARIS-M, a numerical calculation for the pBRDF is made for a roughened surface to account for multiple reflections that light can experience between microfacets. Results from this numerical PRT method shows rays that experience two or more reflections with the microfacet surface can be polarized at an orientation that differs from the analytical single reflection microfacet model. This PRT method is compared against GroundMSPI data of manmade surfaces. An assumption made regarding the pBRDF for this microfacet model is verified with GroundMSPI data of urban areas. This is known as the Spectral Invariance Hypothesis and asserts that the magnitude and shape of the polarized bidirectional reflectance factor (pBRF) is the same for all wavelengths. This simplifies the microfacet model by assuming some surface parameters such as the index of refraction are spectrally neutral. GroundMSPI acquires the pBRF for five prominent region types, asphalt, brick, cement, dirt, and grass, for day-long measurements on clear sky conditions. Over the course of each day, changing solar position in the sky provides a large range of scattering angles for this study. The pBRF is measured for the three polarimetric wavelengths of GroundMSPI, 470, 660, and 865nm, and the best fit slope of the spectral correlation is reported. This investigation shows agreement to the Spectral Invariance Hypothesis within 10% for all region types excluding grass. Grass measurements show a large mean deviation of 31.1%. This motivated an angle of linear polarization (AoLP) analysis of cotton crops to isolate single reflection cases, or specular reflections, from multiple scattering cases of light in vegetation. Results from this AoLP method show that specular reflections off the top surface of leaves follow the Spectral Invariance Hypothesis.
2

Finansiering inom bostadsrättsektorn : En studie om en alternativ finansieringsmodell / Financing in the condominium sector : A study about an alternative financing model

Jillersberg, Madeleine, Denlert, Adam January 2019 (has links)
Priserna på den svenska bostadsmarknaden har stigit ovanligt mycket de senaste åren. En konsekvens av detta är att allt fler får det svårare att ta sig in på bostadsmarknaden och köpa sin första bostad. Inte minst förstagångsköpare som har svårt att spara ihop till den höga insatsen som ofta krävs eller bli beviljade lån hos bankerna. En alternativ finansieringsmodell har skapats för att göra det lättare för dessa personer att ta sig in på bostadsmarknaden. Denna modell bygger på att det är föreningen som ska stå för den större delen av lånet, istället för köparen. Denna uppsats syftar till att jämföra skillnaderna mellan en bostadsrätt som finansieras på det traditionella sättet och en bostadsrätt som finansieras genom den alternativa finasnieringsmodellen. Den modell som kommer att analyseras i denna studie heter BRF 2.0 och har lanserats av Well Fastigheter. De riktar sig främst till unga personer, därav har en enkätundersökning utförts för att få en inblick i vilken kunskap en förstagångsköpare har inom detta område. Enkäten är utformad som ett kunskapstest som behandlar några av de ekonomiska aspekter i ett bostadsköp som kan vara bra att känna till. Därefter utfördes en intervju med en representant på ett av företagen som har tagit fram denna alternativa investeringsmodell, nå en djupare förståelse för upplägget. Resultaten indikerar att förstagångsköpare besitter bristande kunskap kring bostadsköp för att ur ett ekonomiskt perspektiv kunna ta de mest fördelaktiga besluten. Studien pekar på vikten av att förstagångsköpare själva behöver ta ansvar för att läsa på inom ämnet så de blir medvetna om vilken kunskap de redan besitter och vilken kunskap de behöver lära. Ett problem som nämns i studien är att dessa personer inte alltid är medvetna om vilket område de saknar kunskap inom och kommer därför inte hämta in denna information. Vid detta problem krävs det att högre instanser kliver in och påverkar. Som ett förslag nämns att regering eller utbildningsväsende arbetar vidare med dessa frågor. / Prices on the Swedish housing market has risen the past few years. A consequence by this is that an increasing amount of people struggle to buy their first apartment. In particular people that want to buy their first apartment, which struggle to save enough money for the cash deposit or to get a big enough loan from the bank. In an attempt to solve this, an alternative financing in the condominium sector has been introduced to the market in an attempt to make it easier for people to afford buying their first condoninium. This report aim to compair a condominium that has been funded through the tradtional way and a condominium that has been funded through this alternative way. A survey has been conducted in an attempt to investigate the knowledge whom people that is about the buy their first condoninium possess. An interview has also been conducted to further strenghten our findings from the survey and to get a deeper understanding about this alternative concept. The results indicate that people that’s never bought an apartment before lack some essential knowledge that you need to possess when you buy in apartment in order to make the right choices. This alternative financing might give an opportunity for some people to buy their first apartment, an opportunity they otherwise might not have.
3

A FORMAÇÃO DOS COMPLEXOS AGROINDUSTRIAIS: A BRF E O CRESCIMENTO DE RIO VERDE EM GOIÁS.

Prado, Raquel Maria 18 April 2017 (has links)
Submitted by admin tede (tede@pucgoias.edu.br) on 2017-06-13T13:21:20Z No. of bitstreams: 1 RAQUEL MARIA PRADO.pdf: 2251918 bytes, checksum: de70c45b9649b80ee1ed9c581877a9cc (MD5) / Made available in DSpace on 2017-06-13T13:21:20Z (GMT). No. of bitstreams: 1 RAQUEL MARIA PRADO.pdf: 2251918 bytes, checksum: de70c45b9649b80ee1ed9c581877a9cc (MD5) Previous issue date: 2017-04-18 / This dissertation has the objective of understanding the impact of the socialeconomics results of the installation of Perdigão/BRF in the city of Rio Verde, located in the south-west region of the state of Goiás. The present work was developed through 1990’s decade, and expanded its activities to outside the South region of Brazil, installing a new unity in the South-west of Goiás, more specific in Rio Verde. The agroindustry industry, had been attracted to the region due to, overall, the production capacity of seeds (corn and soy), it’s fiscal tax breaks, and financial incentives offered by the federal, state and city governments, beyond low ambient restrictions in the management of waste. The implantation of the company had start various economic and social impacts, part attributed to the company, either on the urban as well as rural zones, not limiting to the approached city. That been said, transformations on the urban zone (new neighborhoods, new industries, trade and services increase, new jobs, etc.), in the rural zone (chicken and pig flock’s growth, a new integration system, rural establishments increase, integrated associations, etc.), in relation to social effects (IDM, Educational HDI, Incoming HDI, Age HDI and Gini’s Index), and external negatives (violence increase and ambiently infractions occurrence), there were no sufficient elements to prove that the impacts had come exclusively by the implementation of this company in the region. In this context, its noticeable that the consolidation of CAI of meats and the integration of these three complexes (corn, soy and meat) transformed and keep transforming the reality of Rio Verde as well as Goiás’s South-west, promoting the economic development of the city and it’s region. / Esta dissertação tem como objetivo compreender os impactos socioeconômicos resultantes da instalação do complexo agroindustrial da Perdigão/BRF no município de Rio Verde, localizado na microrregião Sudoeste do estado de Goiás. O presente trabalho foi desenvolvido por meio das pesquisas bibliográfica, documental e de campo. A Perdigão, a partir da década de 1990, expandiu suas atividades para fora da região Sul do Brasil, instalando uma unidade no Sudoeste goiano, mais especificamente em Rio Verde. A agroindústria foi atraída para a região devido, sobretudo, à capacidade produtiva de grãos (milho e soja) e aos incentivos fiscais e financeiros oferecidos pelos governos federal, estadual e municipal, além das baixas restrições ambientais no manejo e no uso de dejetos. A implantação da empresa na região desencadeou vários impactos econômicos e sociais, em parte atribuídos a mesma, tanto na área urbana quanto na rural, não se limitando ao município abordado. Assim sendo, transformações na zona urbana (novos bairros, novas indústrias, aumento do comércio e serviços, novos postos de trabalhos etc.), na zona rural (aumento do rebanho de aves e suínos, um novo sistema de integração, aumento dos estabelecimentos rurais, associações de integrados etc.), em relação aos efeitos sociais (melhora no IDM, IDH Educação, IDH Renda, IDH Longevidade e Índice de Gini) e externalidades negativas (aumento da violência e ocorrência de infrações ambientais), não houve elementos satisfatórios que comprovasse que os impactos foram advindos exclusivamente da implantação da empresa na região. Nesse contexto, nota-se que a consolidação do CAI de carnes e a integração de três complexos (milho, soja e carnes) transformaram e continuam transformando a realidade de Rio Verde e, consequentemente, do Sudoeste goiano, promovendo o desenvolvimento econômico do município e da região.
4

Betalningsvilja smarta fastigheter : En studie om långsiktiga faktorer som påverkar betalningsviljan för investeringar i digital teknik

Rosén, Anna January 2020 (has links)
Det finns många faktorer som driver och formar utvecklingen i samhället. Dels ny teknik som erövras och påverkar sin omgivning, dels människan som också är en viktig komponent i utvecklingen. Det är svårt att förutse då vi konstant ändrar vårt sätt att leva. Institutionerna, dvs hur vi organiserar oss med koppling till vår omvärld blir också en betydande faktor som driver utveckling. Det finns knappt 5 miljoner bostäder i Sverige, 1,1 miljoner utav dessa är bostadsrätter där en lekmannastyrelse får i uppdrag att driva förvaltningen som innefattar hållbart och löpande fastighetsunderhåll och långsiktigt hållbar ekonomi. I en tid av konstant utveckling med digitalisering i fokus så krävs nytänkande och anpassningar i dess omvärld. Ny smart teknik lovar kvalitetssäkrad och effektiva lösningar på återkommande analoga vardagssysslor både i privatlivet men också för fastighetsägare. Det finns en betalningsvilja för smart teknik bland bostadsrättsföreningar, men kännedomen om den nya tekniken är låg. För att fatta beslut om investeringar krävs tydlig information, säkrad avkastning och upplevelse av att leverantören har god kompetens. Vid nyproduktion av flerbostadshus finns ett hållbarhetstänk med en tanke på att huset ska leva i 100 år, något som också bör tas i beakt kopplat till fastighetsunderhåll och fördelning av livslängdskostnader över tid. En styrelse i en nyproducerad bostadsrättsförening följer upp sina kostnader för fastighetsunderhåll mer sällan än en bostadsrättsförening med äldre byggnader. Synen på långsiktighet i en bostadsrättsförening motsvarar 11–30 år vilket också påverkar viljan att investera i smart teknik. Påverkansfaktorer för att fatta beslut om investering i smart teknik gynnas av upplevelsen att leverantören av tjänsten har god kompetens och att säkrad avkastning kan utlovas. Sambandet mellan påverkansfaktorerna och digital teknik studeras närmare i denna uppsats.
5

Uppföljning av en energikartläggning : Med fokus på ekologiska, ekonomiska och sociala aspekter / Follow-up of an energy survey : with focus on ecological, economic and social aspects

Ahmed, Chera January 2022 (has links)
Denna studie behandlar en energikartläggning och hur framtida energikartläggningar kan utvecklas för att uppnå hållbar utveckling utifrån samtliga hållbarhetsaspekter. Studien består av analyser och fördjupningar i olika frågor som behandlar hållbar utveckling. Syftet med studien är att analysera och följa upp tidigare utförda energiåtgärder samt följa upp fortsättningen på energikartläggningen genom att analysera resultatet utifrån miljömässiga, ekonomiska och sociala aspekter. Vid en energikartläggning är det ekonomiska och ekologiska aspekter som tas i beaktning samtidigt som sociala aspekter vanligtvis exkluderas. Denna studie skall bidra till möjligheten att inkludera sociala aspekter vid energieffektivisering i en energikartläggning för att kunna bidra till den hållbara utvecklingen i sin helhet. För att kunna uppnå syftet med studien har författaren använt sig av olika kvalitativa metoder som intervju, platsbesök och observation. Genom kvalitativa metoder och tidigare dokumenterade uppföljningar skapas en tolkning över aktuell situation och tidigare utförda åtgärdsförslag. Utöver det har databasen Primo använts samt olika vetenskapliga artiklar och rapporter studerats. Resultatet består av en analys av energikartläggningen och visar hur den kan utvecklas genom att även inkludera sociala åtgärdsförslag. Genom att inkludera samtliga hållbarhetsaspekter erhålles ytterligare ekonomiska besparingar i jämförelse med att bara beakta miljömässiga och ekonomiska aspekter. Sociala åtgärdsförslag bidrar till större engagemang från de boende. Detta resulterar i en ekonomisk besparing i form av ökad miljökompetens och konsekvenstänk gällande energiförbrukning. / This study addresses an energy survey and how future energy surveys can develop to achieve sustainable development based on all sustainability aspects. The study consists of analyzes and in-depth questions on various issues about sustainable development. The purpose of the study is to analyze and follow up on previously carried out energy measures and follow up the continuation by analyzing the results based on environmental, economic and social aspects. In an energy survey, the economic and ecological aspects are taken into account, social aspects are usually excluded. This study will contribute to the possibility of including social aspects in an energy survey as well in order to contribute to the sustainable development as a whole. In order to achieve the purpose of the study, the author has used various qualitative methods such as interviewing, site visits and observation. Qualitative methods and previously documented follow-ups of the energy survey, creates an interpretation of the current situation and previously implemented action propsals. In addition, the Primo database has been used and various scientific articles/reports have been studied. The results consists of an analysis of the energy survey and shows how it can develop by including social aspects. By including all sustainability aspects, additional financial savings are obtained compared to only environmental and economic considerations. Social action proposals contribute to greater involvement of the residents. This results in an economic saving in form of increased environmental competence and consequent thinking on energy consumption.
6

Phytoremédiation d’un sol contaminé par des contaminants organiques et inorganiques

Fortin Faubert, Maxime 04 1900 (has links)
Le nombre important de sites contaminés au Québec (Canada) et partout dans le monde est une problématique de santé publique majeure en raison des risques toxicologiques qu’ils présentent pour la santé humaine et environnementale. Dans la municipalité de Varennes (Québec, Canada), située sur la rive sud de l'Île de Montréal, les activités d’une ancienne usine pétrochimique (Pétromont Inc.) ont conduit à l’accumulation de concentrations modérées à élevées d’éléments traces métalliques (ETMs), de biphényles polychlorés (BPCs), d’hydrocarbures pétroliers aliphatiques (C10-C50) et d’hydrocarbures aromatiques polycycliques (HAPs) sur les terrains de la compagnie. En 2010, une culture intensive de saule sur courtes rotations (CICR) a été établie sur le site, afin d’y conduire une expérience de phytoremédiation à grande échelle. Bien que cette plantation de Salix miyabeana ait été implantée dans une optique d'assainissement, aucun effet significatif n'a été signalé sur la concentration des contaminants du sol au cours des premières années de croissance. Les processus d'assainissement basés sur l’utilisation de végétaux peuvent être difficiles à prévoir en milieux naturels et nécessitent des améliorations afin d'en augmenter leur efficacité. La fertilisation des sols avec des amendements organiques, ainsi que la manipulation du microbiome végétal, sont deux techniques agronomiques couramment utilisées pour la gestion des cultures traditionnelles, afin d’augmenter la production de biomasse et améliorer la santé générale des végétaux. Ces approches peuvent également influencer la mobilité et la biodisponibilité de certains composés du sol. Puisque de telles modifications sont connues pour avoir le potentiel d’améliorer considérablement l’efficacité des végétaux à éliminer ou à transformer certains contaminants du sol, ces deux techniques agronomiques présentent un intérêt grandissant dans le domaine de la phytoremédiation. Cette recherche doctorale vise donc à améliorer les connaissances scientifiques dans le domaine de la phytoremédiation appliquée à grande échelle en abordant certains aspects qui touchent à ces deux approches agronomiques. En utilisant la plantation de saules déjà établie, une première étude a été réalisée afin d’évaluer l’impact d’un amendement de sol organique sur l’efficacité phytoremédiatrice des deux cultivars de saules (‘SX61’ et ‘SX64’). À l’intérieur de cette plantation, le sol de certaines parcelles expérimentales a été recouvert de bois raméal fragmenté (BRF) de saules, combiné, ou non, avec du substrat de champignons épuisé (SCE) de Pleurotus ostreatus. Après trois saisons de croissance, les résultats ont montré que l’ajout de SCE au BRF n’avait eu aucun effet sur la croissance des saules, ainsi que sur leur efficacité à extraire ou à réduire la concentration des contaminants présents sur le site. Les résultats suggèrent néanmoins que le BRF contribue à immobiliser certains HAPs dans le sol, en plus d’augmenter l’efficacité des saules à phytoextraire le Zn. La présence de saules semble avoir réduit de façon significative l’atténuation naturelle des C10-C50 sur le site. De plus, les concentrations de BPCs, de Cd, de Ni et de dix HAPs, ont montré des oscillations saisonnières, ce qui suggère que l’évapotranspiration qui a lieu à l’intérieur de la plantation de saules provoque un important flux d'eau et de contaminants solubles en direction des racines. Ainsi, la concentration de certains contaminants pourrait avoir tendance à augmenter à l’intérieur d’une dense plantation de saules au fil du temps. Une deuxième étude a été réalisée à l’intérieur de cette même plantation, afin de vérifier si les augmentations de concentration observées précédemment pouvaient être liées à l’évapotranspiration qui a lieu à l’intérieur d’une plantation de saules. Dans l’optique d’éliminer l’effet de transpiration, des coupes de saules ont été effectuées dans certaines parcelles de la plantation, puis les concentrations des contaminants organiques et inorganiques ont été suivies au fil du temps (24 mois), et comparées avec celles observées dans les parcelles non coupées. Les résultats obtenus ont montré que l'élimination des saules avait bel et bien limité l'accumulation de certains contaminants à la surface du sol, tels qu’observé dans les parcelles non coupées. Ces résultats suggèrent donc encore une fois que la culture intensive de saules à courte rotation peut entrainer une migration de certains contaminants en direction des racines et ainsi augmenter leurs concentrations à la surface du sol près des zones racinaires. Très peu d’études ont rapporté des résultats qui semblent contredire les multiples avantages de purification qui sont habituellement mis de l’avant en phytoremédiation. Toutefois, de tels effets sur la mobilisation des contaminants pourraient être pertinents et souhaitables dans un contexte de gestion du risque. La troisième et dernière étude présentée dans cette thèse explore la diversité des communautés microbiennes associées aux racines des deux cultivars de saules établis sur le site expérimental depuis plusieurs années (six années). Des études antérieures ont permis d’en apprendre davantage sur la composition du microbiome racinaire et rhizosphérique du saule poussant en milieux contaminés, mais la plupart de celles-ci ont été menées sur des individus relativement jeunes. Par conséquent, peu d’information existe concernant les associations microbiennes des individus plus âgés qui ont été établis en milieux contaminés. La caractérisation des communautés fongiques, bactériennes et archéennes a permis de montrer des différences de composition entre les deux cultivars de saules, ainsi qu’entre leurs compartiments (i.e. racines et rhizosphère). Certains groupes taxonomiques, appartenant à chacun des trois domaines, se sont démarqués, de par leur abondance, ou par leurs fonctions écologiques déjà connues et potentiellement bénéfiques pour la survie des végétaux, ou pour augmenter la dégradation et l'extraction de divers contaminants. Cette étude fournit donc de précieuses informations qui pourront servir à l’amélioration de certaines approches d'ingénierie du microbiome favorisant l'établissement, la survie, la croissance et les performances d’assainissement de Salix spp. établis en milieux contaminés. L’ensemble des résultats présentés dans cette thèse ont permis d’alimenter différentes réflexions sur l’intérêt d’utiliser certains amendements organiques et de caractériser le microbiome racinaire et rhizosphérique des saules afin d’améliorer les pratiques et la mise en oeuvre de la phytoremédiation par des saules. Cette thèse met également en lumière un phénomène de migration des contaminants, influencé par la présence de plantes à croissance rapide, qui représente un obstacle pour l’évaluation des performances d’assainissement par des approches de phytoremédiation notamment par des saules. / The large number of contaminated sites in Quebec (Canada) and all around the world is a major public problem because of the toxicological risks they present for human and environmental health. In the municipality of Varennes (Quebec, Canada), located on the south shore of the Island of Montreal, the activities of a former petrochemical plant (Pétromont Inc.) have led to the accumulation of moderate to high concentrations of traces elements (TEs), polychlorinated biphenyls (PCBs), aliphatic petroleum hydrocarbons (C10-C50) and polycyclic aromatic hydrocarbons (PAHs) on the land. In 2010, a short rotation intensive culture (SRIC) of willow has been established on the site, in order to conduct a field-scale phytoremediation experiment. Although this plantation of Salix miyabeana was established with a remediation view, no significant effect was reported on the concentration of soil contaminants during the first years of growth. Plant-based remediation processes can be difficult to predict in the fiel and require improvement in order to increase their effectiveness. Fertilization with organic amendments, as well as manipulating the plant microbiome, are two agronomic techniques commonly employed in traditional crop management, in order to increase biomass production and improve overall plant health. These approaches can also influence the mobility and bioavailability of some compounds in the soil. Since such modifications are known to have the potential to significantly improve the efficiency of plants in removing or transforming soil contaminants, these two agronomic techniques are of growing interest in the field of phytoremediation. This doctoral research aims to improve scientific knowledge in the field-scale phytoremediation application by addressing some aspects that affect these two agronomic approaches. Inside the already established willow plantation, a first study was carried out to assess the impact of soil organic amendment on the phytoremediation efficacy of the two willow cultivars (‘SX61’ and ‘SX64’). The soil of some experimental plots was covered with ramial chipped wood (RCW) combined or not with spent mushroom substrate (SMS) of Pleurotus ostreatus. After three growing seasons, the results showed that the addition of SMS to the RCW had no effect on the growth of the willows, as well as on their effectiveness in removing or reducing the concentration of contaminants on the site. The results nevertheless suggest that RCW helps immobilize some PAHs in the soil, in addition to increasing the efficiency of willows to phytoextract Zn. The presence of willows appears to have significantly reduced the natural attenuation of C10-C50 on the site. In addition, the concentrations of PCBs, Cd, Ni and ten PAHs, showed seasonal oscillations, which suggests that the evapotranspiration inside the willow plantation mobilized some contaminants towards the rooting zones. Thus, the concentration of certain contaminants may tend to increase within a dense willow plantation over time. A second study was carried out inside the same plantation, in order to verify if the increases in concentration observed previously could be linked to the evapotranspiration that takes place inside a willow plantation. In order to eradicate the effect of plant transpiration, willows were harvested in certain plots of the plantation. The concentrations of organic and inorganic contaminants were followed over time (24 months) and compared with those observed in the unharvested plots. The results obtained showed that the removal of the willows limited the accumulation of certain contaminants on the soil surface, as observed in the uncut plots. These results suggested once again that the short rotation intensive culture of willows can lead to the migration of certain contaminants towards the roots and thus increase their concentrations on the soil surface near the root zones. Very few studies have reported results that seem to contradict the multiple purification benefits that are usually put forward in phytoremediation. However, such effects on contaminant mobilization could be relevant and suitable in a risk management context. The third and final study presented in this thesis explores the microbial communities associated with the roots of the two willow cultivars established on the experimental site for several years (six years). Root and rhizosphere microbial communities of Salix spp. have been studied in contaminated environments, but most of studies have been carried out on relatively young hosts. Therefore, little information exists regarding the microbial communities associated with older willows established in contaminated environments. The characterization of fungal, bacterial and Archean communities has shown differences in composition between the two willow cultivars, as well as between their compartments (i.e., roots and rhizosphere). Some taxonomic groups, belonging to each of the three domains, caught our attention, either by their abundance, or by their ecological functions already known to be potentially beneficial for the plant survival, or for increasing the degradation and extraction of various contaminants. This study therefore provides valuable information that can be used to improve certain microbiome engineering approaches that promote the establishment, survival, growth and phytoremediation performance of Salix spp. in contaminated environments. All the results presented in this thesis have fueled various reflections on the interest of using soil organic amendments and characterizing the root and rhizosphere microbiome of willows in order to improve the practices and implementation of phytoremediation with willows. This thesis also highlights a phenomenon of contaminant migration, influenced by the presence of fast-growing woody plants, which represents an obstacle for the evaluation of phytoremediation performance approaches with willows.

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