Among ornamental plants, roses (Rosa L.) are considered the most economically important, being among the most popular garden shrubs, as well as the favorite cut flowers sold by florists. In the past roses have been classified as fairly salt-sensitive, however, recent nutrition studies suggest that they may actually tolerate moderate to relatively high salinities. The general objective of this research was to reassess the limits of tolerance to salinity of roses and the influence of the rootstock used, to determine the ameliorative properties of supplemental Ca2+ on the response to salt stress, and to establish the influence of Na+- and Cl--counter ions on the detrimental effects caused by these salinizing elements. The NaCl or NaCl-CaCl2-salinity tolerance limit for greenhouse roses, although greatly influenced by the rootstock, was between 12 and 15 mmol.L-1. Plants grafted on ?Manetti? sustained their productivity/quality characteristics for longer time periods, tolerated greater salinity concentrations, and accumulated less Cl- and Na+ in leaves of flowering shoots than those grafted on ?Natal Briar?, confirming the greater ability of the former rootstock to tolerate salt stress. Supplementing the saline solution with 0-10 mmol.L-1 Ca2+ (as CaSO4) did not alleviate the harmful effects caused by NaCl-salt stress (12 mmol.L-1) on the productivity and quality responses of roses. The detrimental effects caused by Na- and Cl-based salinity were greatly influenced by the composition of the salt mixtures (i.e. their counter ions). Sodium sulfate and CaCl2 were the least harmful salts; NaCl had intermediate effects, while NaNO3 and KCl were the most deleterious. Among the most distinguishable effects caused by the more toxic Na+ and Cl- counter ions were lower osmotic potential (piSS) and greater electrical conductivity (ECSS) of the salinized solutions, markedly increased uptake and/or transport of either Na+ or Cl- to the flowering shoot leaves, and altered uptake and/or transport of other mineral nutrients. Computations of the saline solutions? chemical speciation revealed that salts containing divalent ions had lower ionization and exhibited greater ion associations compared to monovalent ion salts, rendering a lower number in free ions/molecules in solution which caused greater SS and lower ECSS in those solutions.

Texte remanié de : Dissertation : ? : Tübingen, Universität : 1998. / Bibliogr. p. [505]-541. Index.

Artificial magnetic materials (AMMs) are a type of metamaterials which are engineered to exhibit desirable magnetic properties not found in nature. AMMs are realized by embedding electrically small metallic resonators aligned in parallel planes in a host dielectric medium. In the presence of a magnetic field, an electric current is induced on the inclusions leading to the emergence of an enhanced magnetic response inside the medium at the resonance frequency of the inclusions. AMMs with negative permeability are used to develop single negative, or double negative metamaterials. AMMs with enhanced positive permeability are used to provide magneto-dielectric materials at microwave or optical frequencies where the natural magnetic materials fail to work efficiently. Artificial magnetic materials have proliferating applications in microwave and optical frequency region. Such applications include inversely refracting the light beam, invisibility cloaking, ultra miniaturizing and frequency bandwidth enhancing low profile antennas, planar superlensing, super-sensitive sensing, decoupling proximal high profile antennas, and enhancing solar cells efficiency, among others. AMMs have unique enabling features that allow for these important applications. Fundamental limitations on the performance of artificial magnetic materials have been derived. The first limitation which depends on the generic model of permeability functions expresses that the frequency dispersion in an AMM is limited by the desired operational bandwidth. The other constraints are derived based on the geometrical limitations of inclusions. These limitations are calculated based on a circuit model. Therefore, a formulation for permeability and magnetic susceptibility of the media based on a circuit model is developed. The formulation is in terms of a geometrical parameter that represents the geometrical characteristics of the inclusions such as area, perimeter and curvature, and a physical parameter that represents the physical, structural and fabrication characteristics of the medium. The effect of the newly introduced parameters on the effective permeability of the medium and the magnetic loss tangent are studied. In addition, the constraints and relations are used to methodically design artificial magnetic material meeting specific operational requirements. A novel design methodology based on an introduced analytical formulation for artificial magnetic material with desired properties is implemented. The synthesis methodology is performed in an iterative four-step algorithm. In the first step, the feasibility of the design is tested to meet the fundamental constraints. In consecutive steps, the geometrical and physical factors which are attributed to the area and perimeter of the inclusion are synthesized and calculated. An updated range of the inclusion's area and perimeter is obtained through consecutive iterations. Finally, the outcome of the iterative procedure is checked for geometrical realizability. The strategy behind the design methodology is generic and can be applied to any adopted circuit based model for AMMs. Several generic geometries are introduced to realize any combination of geometrically realizable area and perimeter (s,l) pairs. A realizable geometry is referred to a contour that satisfies Dido's inequality. The generic geometries introduced here can be used to fabricate feasible AMMs. The novel generic geometries not only can be used to enhance magnetic properties, but also they can be configured to provide specific permeability with desired dispersion function over a certain frequency bandwidth with a maximum magnetic loss tangent. The proposed generic geometries are parametric contours with uncorrelated perimeter and area function. Geometries are configured by tuning parameters in order to possess specified perimeter and surface area. The produced contour is considered as the inclusion's shape. The inclusions are accordingly termed Rose curve resonators (RCRs), Corrugated rectangular resonators (CRRs) and Sine oval resonators (SORs). Moreover, the detailed characteristics of the RCR are studied. The RCRs are used as complementary resonators in design of the ground plane in a microstrip stop-band filter, and as the substrate in design of a miniaturized patch antenna. The performance of new designs is compared with the counterpart devices, and the advantages are discussed.

Il est bien connu que la synchronisation de l'activité oscillatoire dans les réseaux de neurones joue un rôle important dans le fonctionnement du cerveau et pour le traitement des informations données pas les neurones. Cette thèse porte sur l'analyse de l'activité de synchronisation en utilisant des outils et des méthodes issues de la théorie du contrôle et de la théorie de la stabilité. En particulier, deux modèles ont été étudiés pour décrire l'activité oscillatoire des réseaux de neurones : le modèle de Kuramoto et le modèle de Hindmarsh-Rose. Une partie de ce manuscript est consacrée à l'étude du modèle de Kuramoto, qui est un des systèmes les plus simples utilisé pour modéliser un réseau de neurones, avec une connexion complète (all-to-all). Il s'agit d'un modèle classique qui est utilisé comme une version simplifiée d'un réseau de neurones. Nous construisons un système linéaire qui conserve les informations sur les fréquences naturelles et sur les gains d'interconnexion du modèle original de Kuramoto. Les propriétés de stabilité de ce modèle sont ensuite analysées et nous montrons que les solutions de ce nouveau système linéaire convergent vers un cycle limite périodique et stable. Finalement, nous montrons que contraint au cycle limite, les dynamiques du système linéaire coïncident avec le modèle de Kuramoto. Dans une seconde partie, nous avons considéré un modèle de réseau de neurones plus proche de la réalité d'un point de vue biologique, mais qui est plus complexe que le modèle de Kuramoto. Plus précisément, nous avons utilisé le modèle de Hindmarsh-Rose pour décrire la dynamique de chaque neurone que nous avons interconnecté par un couplage diffusif (c'est à dire linéaire). A partir des propriétés de semi-passivité du modèle de Hindmarsh- Rose, nous avons analysé les propriétés de stabilité d'un réseau hétérogène de Rindmarsh-Rose. Nous avons également montré que ce réseau est pratiquement synchronisé pour une valeur suffisamment grande du gain d'interconnexion. D'autre part, nous avons caractérisé le comportement limite des neurones synchronisés et avons établi une approximation de ce comportement par une moyenne des dynamiques de tous les neurones.

Les transporteurs vésiculaires du glutamate (VGLUTs) sont impliqués dans la recapture du glutamate du cytosol vers les vésicules présynaptiques. Depuis leurs caractérisations récentes en 2000, leurs implications dans plusieurs maladies neurodégénératives ont été démontrées. Ils jouent ainsi un rôle primordial dans la transmission nerveuse glutamatergique. Deux colorants naturels, le Rose Bengale et le Bleu Trypan, restent les meilleurs inhibiteurs connus à ce jour, avec respectivement des CI50 de 25 et 50 nM. Dans un premier temps, nous avons conçu et optimisé une série d'analogues basée sur le synthon Rose Bengale (inhibiteur non-compétitif). Ce travail a notamment permis de mettre en évidence l'effet des formes tautomères (quinone et lactone) sur l'inhibition des VGLUTs. Ainsi la forme quinonique, présente à pH physiologique, a été confirmée comme étant la seule capable de bloquer la recapture du glutamate. Dans un second temps, nous nous sommes intéressés à la famille du Bleu Trypan (inhibiteur compétitif) et nous avons déterminé la structure minimale active avec l'objectif de rendre ces molécules plus " drug-like ". En effet, l'intérêt de ce projet est de développer de petites structures aisément radiomarquables pour une utilisation dans un contexte physio-pathologique.

L'objectif global de ce travail est d'étudier une modélisation multi échelle et de développer une méthode adaptée pour la simulation numérique du processus d'érosion à l'échelle du bassin versant. Après avoir passé en revue les différents modèles existants, nous dérivons une solution analytique non triviale pour le système couplé modélisant le transport de sédiments par charriage. Ensuite, nous étudions l'hyperbolicité de ce système avec diverses lois de sédimentation proposées dans la littérature. Concernant le schéma numérique, nous présentons le domaine de validité de la méthode de splitting, pour les équations modélisant l'écoulement et celle décrivant l'évolution du fond. Pour la modélisation du transport en suspension à l'échelle de la parcelle, nous présentons un système d'équations couplant les mécanismes d'infiltration, de ruissellement et le transport de plusieurs classes de sédiments. L'implémentation et des tests de validation d'un schéma d'ordre élevé et de volumes finis bien équilibré sont également présentés. Ensuite, nous discutons sur l'application et la calibration du modèle avec des données expérimentales sur dix parcelles au Niger. Dans le but d'aboutir la simulation à l'échelle du bassin versant, nous développons une modélisation multi échelle dans laquelle nous intégrons le taux d'inondation dans les équations d'évolution afin de prendre en compte l'effet à petite échelle de la microtopographie. Au niveau numérique, nous étudions deux schémas bien équilibrés : le schéma de Roe basé sur un chemin conservatif, et le schéma avec reconstruction hydrostatique généralisée. Enfin, nous présentons une première application du modèle avec les données expérimentales du bassin versant de Ganspoel qui nécessite la parallélisation du code.

Over the past twenty years, the idea that planning and development practices should be ‘sustainable’ has become a key tenet of discourses characterising the field of planning and development. As part of the agenda to balance and integrate economic, environmental and social interests, democratic participatory governance arrangements are frequently purported to be necessary to achieve ‘sustainable development’ at both local and global levels. Despite the theoretical disjuncture between ideas of democratic civic participation, on the one hand, and civic participation as a means to achieve pre-determined sustainability goals on the other, notions of civic participation for sustainability have become integral features of sustainable development discourses. Underpinned by a conceptual and methodological intent to perform an epistemological ‘break’ with notions of civic participation for sustainability, this thesis explicates how citizens are enrolled in the sustainable development agenda in the discourse of policy. More specifically, it examines how assumptions about civic participation in sustainable development policy discourses operate, and unpacks some discursive strategies through which policy language ‘enrols’ citizens in the same set of assumptions around their normative requirement for participation in sustainable development. Focussing in on a case study sustainable development policy document – a draft regional plan representing a case of ‘enrolling the citizen in sustainability’ - it employs three sociological perspectives/methods that progressively highlight some of the ways that the policy language enjoins citizens as active participants in ‘sustainable’ regional planning. As a thesis-by-publication, the application of each perspective/method is reported in the form of an article prepared for publication in an academic journal. In a departure from common-sense understandings of civic participation for sustainability, the first article examines the governmentality of sustainable development policy. Specifically, this article explores how civic community – particularly community rights and responsibilities – are deployed in the policy discourse as techniques of government that shape and regulate the conduct of subjects. In this respect, rather than seeing civic community as a specific ‘thing’ and participation as corresponding to particular types of ‘activities’, this paper demonstrates how notions of civic participation are constructed and mobilised in the language of sustainable development policy in ways that facilitate government ‘at a distance’. The second article begs another kind of question of the policy – one concerned more specifically with how the everyday practices of subjects become aligned with the principles of sustainable development. This paper, therefore, investigates the role of pedagogy in establishing governance relations in which citizens are called to participate as part of the problematic of sustainability. The analysis suggests that viewing the case study policy in terms of relationships of informal pedagogy provided insights into the positioning of the citizen as an ‘acquirer’ of sustainability principles. In this instance, the pedagogic values of the text provide for low levels of discretion in how citizens could position themselves in the moral order of the discourse. This results in a strong injunction for citizens to subscribe to sustainability principles in a participatory spirit coupled with the requirement for citizens to delegate to the experts to carry out these principles. The third article represents a further breakdown of the ways in which citizens become enrolled in ‘sustainable’ regional planning within the language of the case study policy. Applying an ethnomethodological perspective, specifically Membership Categorization Analysis, this article examines the way ‘the citizen’ and ‘civic values and obligations’ are produced in the interactional context of the text. This study shows how the generation of a substantive moral order that ties the citizen to sustainable values and obligations with respect to the region, is underpinned by a normative morality associated with the production of orderliness in ‘text-in-interaction’. As such, it demonstrates how the production and positioning of ‘the citizen’ in relation to the institutional authors of the policy, and the region more generally, are practical accomplishments that orient the reader to identify him/herself as a ‘citizen’ and embrace the ‘civic values and obligations’ to which he/she is bound. Together, the different conceptual and methodological approaches applied in the thesis provide a more holistic picture of the different ways in which citizens are discursively enrolled in the sustainability agenda. At the substantive level, each analysis reveals a different dimension of how the active citizen is mobilised as a responsible agent for sustainable development. In this respect, civic participation for sustainability is actualised and reproduced through the realms of language, not necessarily through applied occasions of civic participation in the ‘taken-for-granted’ sense. Furthermore, at the conceptual and methodological level, the thesis makes a significant contribution to sociological inquiry into relationships of governance. Rather than residing within the boundaries of a specific sociological perspective, it shows how different approaches that would traditionally be applied in a mutually exclusive manner, can complement each other to advance understanding of how governance discourses operate. In this respect, it provides a rigorous conceptual and methodological platform for further investigations into how citizens become enrolled in programmes of government.

Sammanfattning   Syftet med denna uppsats har varit att studera maskulinitetsnormer i En finir avec Eddy Bellegueule, den franska författaren Édouard Louis debutroman, med utgångspunkt i R. W. Connells maskulina hierarkisystem och maskulinitetsforskning av bland andra Michael Kimmel och Sonya Rose. Romanen, som är självbiografisk, skildrar en homosexuell pojkes uppväxt i en liten by i den franska arbetarklassen. I min uppsats analyserar jag hur hans omgivning förhåller sig till de maskulinitetsnormer som råder i byn, samt vilka överträdelser från normerna som sker. Genom överträdelserna tydliggörs vilka normer som är rådande. Uppenbart blir att det maskulina hyllas och det feminina förtrycks. Romanen bekräftar i stort sett Connells hierarkiuppdelning, den är full av maskulinitetsnormer och män som hyllar det hegemoniska idealet. Resultatet av min analys visar att alla män i romanen är offer för maskulinitetsnormerna, oavsett var i hierarkin de befinner sig, eftersom normerna är destruktiva och begränsar deras livsmöjligheter.

Recently wind resource assessment studies have become an important research tool to identify the possible wind farm locations.  In this thesis work technical analysis was carried out to determine the wind resource potential of two candidate sites in Eritrea with help of suitable software tools. The first site is located along the Red Sea cost which is well known for its wind resource potential, whereas the second site is located in the central highlands of Eritrea with significant wind resource potential. Detailed wind resource assessment, for one year hourly weather data including wind speed and wind direction, was performed for the two candidate sites using MS Excel and MATLAB. The measured wind data at Assab wind site showed that the mean wind speed and power density was 7.54 m/s and 402.57 W/m2 , whereas the mean wind speed and mean power density from Weibull distribution was 7.51 m/s and 423.71 W/m2 respectively at 80m height. Similarly, the measured mean wind speed and mean power density at Dekemahre wind site was obtained to be 5.498 m/s and 141.45 W/m2, whereas the mean wind speed and mean power density from Weibull distribution was 5.4859m/s and 141.057W/m2 respectively. Based on the analysis results Assab wind site classified as wind class-III and Dekemhare as wind class-I.  Wind farm modeling and Annual Energy Production (AEP) estimation was performed for E-82 & E-53 model turbines from Enercon Company with the help of MATLAB and Windpro software. The analysis revealed that Assab wind farm was an ideal site for wind energy production with capacity factor (CF) 53.4% and 55% for E-82 and E-53 turbines respectively. The gross and net AEP for turbine E-82 at Assab wind farm was 469.5 GWh and 446.025 GWh respectively with 95% park efficiency. Similarly, the analysis showed that the CF in Dekemhare site was very low with typical value 14.2% and 15.26% for E-82 and E-53 turbines respectively. The gross and net AEP of that site for model turbine E-53 was 53.5 GWh and 50.825 GWh respectively with 5% wake loss. Finally, a simplified economic analysis was carried out to determine the economic feasibility of possible wind power projects in both sites by assuming investment cost 1600 €/kW for E-82 turbine and 2000 €/kW for E-53 turbine. The total wind farm investment cost was found to be 215.85 and 107.93 Million Euro for E-82 and E-53 model turbines respectively. The levelized cost of energy at Assab and Dekemhare wind farm for E-82 model turbine was 0.0307 €/kWh and 0.5526 €/kWh respectively. The analysis result show that the levelized cost of energy in Dekemhare wind fasrm was much higher than that of Assab wind farm.

This thesis is an attempt at understanding South African photography through the lens of Nontsikelelo “Lolo” Veleko, Tracy Rose, David Goldblatt, Jo Ractliffe and Santu Mofokeng. Through the works discussed this thesis intends to unpack photography as a complex medium similar to that of language and text, as well as attempt to understand how exploring South African experiences and spaces through the lens of photography shapes and mediates them. Furthermore it also attempts to understand how these experiences and spaces conversely affect the discourse of photography or at the very least our perception of it. Through these photographers and their works it is hoped that ultimately the interconnected relationship of exchanging codes that takes place between photography and society will be highlighted. The example of connectivity or dialogue I believe exists between the medium of photography and the physical/social and psychological spaces it photographs will be mediated through Deleuze and Guattari‟s conception of “the wasp and the orchid” where “the wasp becomes the orchid, just as the orchid becomes the wasp...an exchanging or capturing of each other‟s codes”. Other theorists I will be looking at include Vilém Flusser, focusing in particular on his book Towards a Philosophy of Photography, as well as Susan Sontag, Roland Barthes and others. The main aims and objectives of this thesis are to understand the veracity of the documentary image and whether or not the image harbours any objective truth, as well as whether truth, if it can truly be said to exist in the world, resides between the camera and the seen world. This dichotomy is further complicated by the matter of subject-hood and technical and philosophical understandings of the camera as an apparatus. At no point do I aim to be conclusive, rather it is hoped that by developing the dynamic tension between the theory and the image world that I will be able to bring fresh insight into the reading of a changing South African condition and the subject position of the photographer in relation to this condition.