On étudie la cosmologie induite par un gaz parfait de supercordes à température finie. Les effets thermaux et quantiques du gaz de cordes génèrent un potentiel effectif au niveau d'une boucle. A certains points dans l'espace de modules où les masses des états génériquement massifs s'annulent, le potentiel effectif atteint des minima locaux. Les modules qui y sont attirés prennent des masses qui diminuent avec le temps, ce qui permet aux oscillations cohérentes des modules d'être diluées avant la nucléosynthèse. Ainsi le modèle ne rencontre pas le problème des modules cosmologiques. En particulier, on étudie la stabilisation des modules pour la cosmologie induite par i) un gaz de cordes hétérotiques maximalement supersymétriques, ii) un gaz de cordes de type II compactifiées sur un espace de Calabi-Yau de dimension complexe 3. Dans le 1er cas, les minima locaux du potentiel effectif apparaissent aux points de symétries de jauge étendues. Ceux-ci stabilisent tous les modules sauf le dilaton. Dans le 2ème cas, les minima locaux du potentiel effectif sont atteints où des 2- ou 3-sphères dans l'espace de Calabi-Yau s'évanouissent, produisant une transition conifold ou une extension du groupe non Abelien de jauge. Les états non massifs supplémentaires sont engendrés par des D-branes s'enroulant sur les sphères qui s'évanouissent et les modules stabilisés sont ceux qui contrôlent les volumes de ces sphères. Pour les deux cas, on étudie aussi respectivement les théories duales de type I maximalement supersymétrique et hétérotique compactifiée sur K3xT2. On trouve que les modules duaux sont stabilisés par des effets non perturbatifs impliqués par les dualités concernées.

High inflation economies, especially the Latin American cases like Argentina and Brazil, have ultimately been successful in stabilising their prices using the exchange rate as a nominal anchor. Contrary to conventional wisdom inflation in these cases has not been reduced at the cost of temporary recessions, instead, they have shown positive output effects. Various theoretical explanations of such boom-cycles are discussed and a model generating such an outcome is developed. Some empirical evidence is given by the Brazilian "Real Plan" of 1994. Nevertheless, the medium and long-term effects of such programmes can result in recessions and a resumption of high inflation, although the cases show that such "postponed stabilisation costs" can be overcome by adequate and flexible supply-side policies accompanying the stabilisation programme. (author's abstract) / Series: Department of Economics Working Paper Series

L’expression des gènes mitochondriaux est grande partie dirigée par des protéines codées dans le noyau et importées dans l’organite depuis le cytosol. Diverses études ont montré que les protéines de la famille PentatricoPeptide Repeat (PPR) jouent un rôle prépondérant et varié dans ce phénomène. Au cours de ma thèse, j’ai déterminé la fonction de deux nouvelles protéines PPR chez Arabidopsis thaliana, nommées MTSF1 (pour Mitochondrial Stability Factor 1) et PPR24. Chacune de ces protéines est impliquée dans l’expression d’un ARNm mitochondrial codant une sous-unité du complexe I de la chaine respiratoire. J’ai montré que la protéine MTSF1 était requise pour stabiliser l’ARN mitochondrial nad4. Le site de liaison de MTSF1 a été déterminé et il correspond aux vingt derniers nucléotides de l’ARN nad4. Nous pensons donc qu’en s’associant à l’extrémité 3’ terminale de cet ARN, la protéine MTSF1 bloque la progression d’exoribonucléases 3’-5’ et stabilise ainsi l’ARN nad4 in vivo. L’étude de la protéine PPR24 nous a conduit à observer qu’elle était essentielle à la traduction de l’ARNm mitochondrial nad7. J’ai pu démontrer que la protéine NAD7 n’était pas synthétisée chez les mutants ppr24 et que cela était associé à l’absence de ribosomes sur l’ARNm nad7. J’ai aussi montré que la protéine PPR24 pouvait se lier spécifiquement à une courte région située au milieu de la 5’ UTR de l’ARN nad7. La modélisation de la 5’ UTR de cet ARN indique que ce site de liaison se situerait à la base d’une structure en tige-boucle pouvant diminuer fortement l’accessibilité au codon initiateur de la traduction de l’ARN nad7. Il est donc possible que la fixation de la protéine PPR24 puisse déstabiliser cette structure en tige-boucle et permettre aux ribosomes mitochondriaux d’accéder plus facilement au codon AUG. L’ensemble de ces études a permis d’apporter des informations essentielles sur la fonction et le mode d’action des protéines PPR dans l’expression génétique mitochondriale chez les plantes. / Gene expression in mitochondria is for the most controlled by nuclear encoded proteins that are from the cytosol into the organelle. Recent genetic and biochemical analysis have revealed that proteins of the PentatricoPeptide Repeat (PPR) family play preponderant and multifarious role in this process. During my thesis, I characterized the function of two novel Arabidopsis thaliana PPR protein called MTSF1 (for Mitochondrial Stability Factor 1) and PPR24. Each of these proteins is involved in the expression of a single mitochondrial gene encoding respiratory complex I subunit. I showed that the MTSF1 protein is essential for the stabilization of nad4 mRNA. The MTSF1 binding site was determined and was shown to correspond to the last twenty nucleotides of nad4 3’ UTR. We propose that, through an interaction with the extremity of nad4 transcript, the MTSF1 protein blocks the progression of 3’ to 5’ exoribonucleases and protects nad4 mRNA from degradation in vivo. PPR24 analysis indicated that this PPR protein is essential for nad7 mRNA translation. I observed that the NAD7 protein is not produced in ppr24 mutants and that this correlated with lack of ribosome loading of nad7 mature mRNA. I also showed that PPR24 binds to a short RNA fragment with high specificity located in the center of nad7 5’ leader. Structural predictions indicated that PPR24 binding site could correspond to the basis of a long stem-loop RNA structure just upstream of the AUG codon, which could prevent the accessibility to the nad7 translation codon. PPR24 binding could destabilize this stem-loop structure and permit a better access of the ribosome to the nad7 translation initiation codon. These findings shed light on the function and the mode of action of PPR proteins involved in mitochondrial gene expression in plants.

Les procédés par infusion de résine consistant à infuser une résine liquide à travers un empilement de préformes fibreuses sous l’action d’une pression extérieure ap-pliquée à cet empilement. Un drainant peut être utilisé pour créer un lit de résine sur ou sous cet empilement fibreux. Ces procédés sont utilisés pour fabriquer des pièces minces utilisées dans l’aéronautique par exemple. Les caractéristiques physiques et mécaniques des pièces obtenues sont difficiles à prévoir et à contrôler. La simulation numérique peut donc aider à la maîtrise de ces procédés. Dans ce travail, un modèle numérique éléments finis est proposé pour simuler les procédés par infusion de résine. L’écoulement de la résine, considérée comme un fluide Newtonien incompressible, est décrit par les équations de Stokes dans le drainant (milieu très perméable), et par les équations de Darcy dans les préformes fibreuses (milieu faiblement perméable). Ce couplage Stokes - Darcyest réalisé par une approche monolithique, consistant à utiliser un seul maillage pour les deux milieux. La formulation mixte en vitesse - pression, est alors discrétisée par des éléments finis linéaire - linéaire, et stabilisée par une méthode multiéchelle dite "ASGS". L’interface entre Stokes et Darcy et le front de la résine sont chacun représentés par une fonction "Level-Set", et des conditions de couplage sont imposées sur l’interface qui sépare les deux milieux. Au cours du procédé, les préformes subissent de grandes déformations, que ce soit durant la phase de compaction, ou durant l’infusion de la résine. La pression de la résine fait alors gonfler les préformes. Les déformations des préformes sont traitées par une formulation Lagrangienne réactualisée établie en grandes déformations. Les préformes sèches ont un comportement élastique non linéaire, donné dans le sens transverse par l’expérience. L’effet de la résine sur les préformes humides est représenté par le modèle de Terzaghi. Lorsque les préformes se déforment, leur porosité et donc la perméabilité du milieu varient, affectant ainsi l’écoulement. La formule de Carman-Kozeny est utilisée pour relier porosité et perméabilité. Après avoir validé le couplage Stokes - Darcy par de nombreux cas tests et par la méthode des solutions manufacturées, diverses simulations 2D et 3D de procédés par infusion de résine sont présentées, incluant la déformation des préformes. Des comparaisons sont finalement faites avec succès entre simulation numérique et résultats expérimentaux dans un cas de géométrie simple. Des extensions à des cas tridimensionnels présentant des courbures et des variations d’inertie sont proposées en guise de perspectives. / Resin infusion-based processes are good candidates for manufacturing thin composite materials parts such as those used in aeronautics for instance. These processes consist in infusing a liquid resin into a stacking of fibrous preforms under the action of a mechanical pressure field applied onto this stacking where a stiff- distribution medium is also placed to create a resin feeding. Both physical and mechanical properties of the final pieces are rather difficult to predict and control. Numerical simulation are perfectly suited to master these processes. In the present work a numerical finite element modeling framework is proposed to simulate infusion processes. The flow of the assumed Newtonian resin is described in the distribution medium, a highly porous medium, through Stokes’ equations and through Darcy’s equations in the fibrous preforms, very low permeability media. This coupled Stokes-Darcy flow is modeled in a monolithic approach which consists in using a single mesh for both media. The mixed velocity- pressure formulation is then discretized by linear-linear finite elements, stabilized by a so-called ASGS multi-scale approach. Both Stokes-Darcy interface and fluid front are represented individually thanks to "Level-Set" functions, and some specific coupling conditions are prescribed on the interface separating both fluid and porous media. During the process, orthotropic preforms undergo finite strains, either during the compaction stage when resin is not yet present, or during resin infusion. Resin pressure then tends to make the preforms swell. Preforms deformations are represented through an updated Lagrangian formulation for finite deformations. Dry preforms possess a non-linear elastic behaviour in their transverse direction - across their thickness- given by existing experimental measurements. The effect of the presence of resin in the wet preforms is accounted for using a Terzaghi’s equivalent model. Also, when preforms deform their porosity will change, and so will their permeability, modifying the resin flow. A Carman-Kozeny model is then used to relate porosity and permeability. After the Stokes-Darcy coupling is validated both on numerous tests cases and using the method of manufactured solutions, various 2D and 3D simulations of injection and infusion-based processes are analyzed.The latter includ- ing preform deformations along with resin flow. Comparisons with existing experimental measurements permit to validate the approach on a simple geometry. Last, some ex- tensions to more complex 3D cases are proposed as outlooks, including curvatures and thickness variations.

Abstract This thesis is intended to explore the international relations of emerging nation-building in the Somali coast, with particular reference to the un-recognised Republic of Somaliland in the north-western Horn of Africa region. This study focuses on the international relations of Somaliland’s international quest for recognition, linked to its own culturally-rooted internal reconciliatory post-war nation-building efforts. Informed by written as well as first-hand research interviews, particular focus is placed in this study on the interplay of internal and external forces in shaping a strategy by Somaliland’s elites for acquiring international recognition and national selfdetermination. These are placed within the broader regional and international context of attempts to resuscitate the Somali state, an endeavour offering a fitting assessment of different modalities of African nation-building within the greater Somali environment. In relative analytic terms, the competitive international relations of nation-building in Somaliland and state reconstitution in southern Somalia informs the underlying hypothesis of this thesis: Somaliland’s example as a study in the efficacy of the internally-driven, culturally-rooted ‘bottom-up’ approach to post-war nation-building and regional stability, and the implications this holds for prioritising reconciliation between indigenous traditions and modernity in achieving stability in nation-building. By contrast, the internationally-backed ‘top-down’ approach to reconstituting a Mogadishu-based Somali state remains elusive. Yet, the international status quo regarding the affording of diplomatic recognition to what are normally considered secessionist ‘break-away’ regions of internationally recognised states, complicates Somaliland’s culturally rooted ‘bottom-up’ modalities. It also challenges the African Union (AU) during the ‘good governance’ era of the New Partnership for Africa’s Development (NEPAD), a context within which Somaliland fits comfortably as a good citizen of the international community. The international relations of the Somaliland nation-building enterprise is approached from a ‘quadrilateral framework’ of interactive elements to the Somaliland experience: Reconciliation, Reconstruction, Religion and Recognition. This framework informs the four core chapters of the thesis.

En cas de catastrophes importantes, telles qu’un tremblement de terre ou un incendie, l’efficacité des forces de la sécurité civile nécessite une bonne coordination des différents groupes d’intervention. Suivant la nature et l’importance du sinistre, l’infrastructure des moyens de communications classique peut être détruite. Les forces d’intervention ont donc besoin de nouveaux outils de communication dits réseaux de circonstance. Ces réseaux posent de nouveaux problèmes de routage, pour maintenir la connectivité, mais aussi d’allocation de ressources, particulièrement importante dans un contexte de sécurité où les communications doivent être garanties. Dans une première partie, nous avons abordé la problématique de l’allocation de ressources dans les réseaux de circonstance utilisant le partage TDMA. Nos solutions visent une répartition équitable des canaux et prennent en compte une zone d’interférence double de celle de transmission.Evaluer de nouvelles politiques dans des réseaux déployés sur des scènes de catastrophe nécessite de nouveaux modèles de mobilité. Nous avons donc également développé un nouveau modèle de mobilité spécifique au déplacement des équipes de la sécurité civile. / When a major disaster occurs, such as an earthquake or fire, the efficiency of the rescue workers depends of the coordination between the different emergency teams. This coordination needs reliable communication equipments. In such a situation, however, the infrastructure for wireless communication is generally destroyed or unusable. It is therefore necessary to find adapted communication tools for the rescue workers known as opportunistic networks. These networks pose new challenging problems such as, for instance, resource allocation which is particularly important for the QoS satisfaction. In the first part of our thesis, we addressed the problem of resource allocation in ad hoc networks using the TDMA access mechanism. Our solutions aim to perform a fair distribution of channels and take into account an interference area twice as large as the transmission range. Evaluation of new policies for opportunistic networks deployed in disaster areas requires new mobility models. We developed a novel mobility model dedicated to the movement of rescue workers. Our model includes the group mobility and some characteristics of human mobility. It also incorporates a mechanism to circumvent obstacles presents in the simulation area.

Dans une configuration optimale, la couche photo-active d’une cellule solaire organique forme une hétérojonction volumique entre un matériau donneur et un matériau accepteur d’électrons. Cette morphologie optimale se trouve dans un état thermodynamique métastable. En cours de fonctionnement, l’absorption incidente provoque une élévation de la tempéra- ture des dispositifs. L’apport d’énergie thermique au système le fait évoluer vers un état thermodynamique stable correspondant à une micro-séparation de phase entre les deux matériaux nuisible aux performances photovoltaïques du dispositif. La solution à cette problématique envisagée dans cette thèse est de figer la morphologie optimale de la couche photo-active par réticulation chimique. Dans le but de prévenir la diffusion et la cristallisation des dérivés du fullerène, plusieurs approches ont été étudiées : la formation d’une maille de polymères réticulés, l’accroche des dérivés du fullerène aux chaînes du polymères ou la liaison entre plusieurs dérivés du fullerène. Les différentes fonctions réticulantes utilisées dans ces approches sont l’allyle, le cinnamate, l’anthracène et l’azoture. Au cours de ces travaux, des résultats satisfaisants ont été obtenus avec la fonction azoture. Basé sur cette fonction, nous avons développé un additif qui permet d’augmenter notablement la stabilité thermique des cellules solaires réticulées. Cette approche a été validée sur plusieurs couples de matériaux polymères/dérivés du fullerène à l’état de l’art. / Efficient bulk-heterojunction solar cells require an interpenetrating network of electron donating and electron accepting materials. Indeed, the optimum nano-sized phase segregation is a thermodynamically metastable system. Under operating conditions, especially under solar illumination, the temperature of the solar cell increases significantly. Adding thermal energy to the system leads to further micro-phase separation that is harmful for photovoltaic device performances. In order to freeze the optimal morphology, several approaches based on chemical cross-linking have been studied : formation of cross-linked polymer network, binding fullerene derivatives to polymer side chains or cross-linking between fullerene derivatives. Different cross-linkable functions have been used : allyl, cinamate, anthracene and azide. A versatile stabilization strategy of bulk heterojunctions morphology has been found by mean of incorporating a cross-linkable additive in low amounts with different polymer :fullerene blends. This approach is validated on multiple materials at the state-of-the-art.

Pour contrôler les systèmes chimiques complexes, les outils de la chimie supramoléculaire s’avèrent puissants et représenteront certainement une des technologies clef du 21e siècle. En effet, la réversibilité intrinsèque des liaisons chimiques impliquées dans la formation d'assemblages supramoléculaires apporte à ces systèmes un caractère "adaptatif", capable de réorganiser leur structure en fonction des conditions environnementales. Ce comportement s’avère totalement inédit malgré le grand nombre d’études effectuées sur cette famille de molécules du fait de ses propriétés photoactives. Au cours des dernières années, notre groupe a synthétisé de nombreux dérivés de triarylamines (TAAs), qui ont été utilisés pour produire des architectures supramoléculaires multifonctionnelles. En fonction des différents groupements qui substituent ce coeur TAA, diverses morphologies ont pu être observées et les propriétés physiques de ces auto-assemblages produits dans des solvants non polaires tels que les solvants chlorés ou le toluène se sont également révélées variées (propriétés cristal-liquide, conductrices, plasmoniques...). A partir de ces travaux, mon projet de thèse consistait en deux objectifs: a) étudier l'auto-assemblage et les propriétés de ces composés TAA dans des solvants polaires comme l'eau ou le méthanol. Pour cela, comme tenu du caractère hydrophobe des TAAs, il s'avérait nécessaire de synthétiser de nouvelles molécules incorporant des groupements latéraux favorisant la solubilité dans de tels solvants; b) stabiliser les auto-assemblages de triarylamine par polymérisation covalente et étudier les propriétés physiques associées à ces nouvelles structures. Pour cela, il convenait de synthétiser de nouvelles molécules incorporant des groupements polymérisables sur les chaines latérales, qui n'influençaient pas les propriétés d'auto-assemblages des TAAs. [...] / Based on the unique directionality and reversibility of non-covalent interactions, supramolecular self-assembly works as an elegant methodology to construct multifunctional hierarchical architectures. Inspired by nature, where water provides a vital environment for biological process such as biomacromolecular folding, water-soluble supramolecular polymers have been prepared and studied so as to mimic related biological systems. On the other hand, owing to the dynamic nature of their non-covalent bonds, supramolecular polymers often lack mechanical robustness. Thus, cross-linking strategies have been developed in order to combine highly ordered molecular arrangement inherent to the sef-assembly and mechanical robustness of the covalent backbone, which might bee promising to reach functional materials for practical applications. In this thesis, we focus on well-designed triarylamine molecules which are known to self-assemble into supramolecular polymers with excellent physical properties, as discovered by our group. In particular, molecules studied in this manuscript are based on tris-amide triarylamine scaffold known to produce self-assemblies with metallic conductivity and self-healing behavior. First, we studied the self-assemblies of three novel tris-amide triarylamine derivatives decorated with either poly(ethylene glycol) (PEG), peptide or cyanine dyes side chains on the three amide positions in polar solvents, i.e. either water or methanol. Characterizations by various physico-chemical techniques (NMR, UV-Vis absorption, fluorescence, infrared spectroscopies, microscopies, scatterings) demonstrated the formation of fibrillar aggregates for all molecules in such polar environments. Overall, this study suggest that the triarylamine core act as the main driving force for the self-assembly into columnar aggregates while side chains ensure solubility in these solvents and/or favor the formation of chiral architectures. In a second study, we investigated the formation of tris-amide triarylamine supramolecular polymers decorated with norbornene and siloxane end side chains, which could be further used to freeze the self-assembled structures by ring opening metathesis polymerization and sol-gel methods, respectively. [...]

Supported metal nanoparticles present unique chemical and physical properties compared to their bulk counterparts. Their high surface energy provides outstanding catalytic activities, opening the door not only to improved catalytic systems but also to new catalytic routes. However, their high surface energy and liquid-like properties are responsible for their instability, usually leading to agglomeration under reaction conditions. This thesis seeks to investigate a novel nanoparticle stabilisation approach by physical confinement on curved supports. Specifically, the project focusses on the stabilisation of cobalt and gold nanoparticles on nanostructured -Al2O3 supports, motivated by the industrial interest of Sasol UK. The research hypothesis is validated by detailed characterisation and catalytic testing of a range of catalysts using different metal loadings and support morphologies. To enable this study, the mechanism of the hydrothermal synthesis of a series of nanostructured -Al2O3 supports with either flat or curved surfaces and differing degrees of curvature has been elucidated, leading to the development of a semi-continuous manufacturing process. Varying the method for loading cobalt onto -Al2O3 supports highlights the implications of method selection on the particle size, reducibility, composition and the tendency to form irreducible cobalt oxides, all of which affect the catalytic activity. The ability to obtain and stabilise small nanoparticles with low loading (1 wt% Co) without the formation of irreducible cobalt oxides exposes the beneficial effect of the support curvature. Specifically, the stabilisation effect is theorised to be effective under the condition where the ratio of the diameter of the nanoparticle (P) and the nanorod (R) is less than one, P:R < 1. In several cases, after cobalt or gold reduction, elongation of the nanoparticles, as opposed to agglomeration, is observed by electron microscopy confirming that the particles are physical confined by the curved surface in all directions except along the nanorod axis. In these cases, highly active Co/-Al2O3 and Au/-Al2O3 catalysts are reported for NH3 decomposition and CO oxidation respectively. For higher metal loadings (> 5 wt% Co), where the particles are the same size or larger than the diameter of the nanorod cross-section, no noticeable stabilisation effect is reported. The results of this thesis are scientifically and industrially important. If applied correctly, this novel nanoparticle stabilisation strategy could be used to design catalysts with improved activity and stability, resulting in lower operational costs and improved resource efficiency.

Waste Stabilisation Ponds (WSPs) are a relatively simplistic and non-intensive wastewater treatment technology; with various WSP configurations widely employed to treat a range of different wastewaters the world over. Whilst the advantages of WSP treatment are both numerous and well recognized, performance problems relating to the presence of occasionally large and unpredictable quantities of plankton (both algal and zooplankton) biomass in the final pond effluents have posed significant operational problems for WSP operators; with this suspended biomass representing the single biggest drawback associated with the technology. Research conducted during this project was concerned with assessing a selection of so-called ‘advanced’ in-pond treatment processes for the upgrading or polishing of a final WSP effluent. The particular research emphasis was on the removal of problematic algal and zooplankton biomass from WSP effluent prior to Dissolved Air Flotation/Filtration (DAF/F) treatment and wastewater reuse at the Bolivar Wastewater Treatment Plant (WWTP) north of Adelaide. The in situ WSP upgrade systems assessed in this thesis were: the native floating plant ‘Duckweed’ (DW); ‘Rock Filters’ (RFs); and an artificial ‘Attached-Growth Media’ (AGM); all of which were assessed for their relative treatment efficacies parallel to a non-interventional ‘Open Pond’ (OP) system which served as an effective control. These performance comparisons were assessed on a pilot-scale using a custom made pilot treatment plant which was located at the Bolivar WWTP. Performance monitoring was periodically carried out over a 12 month period from July 2005–August 2006, with algal and zooplankton populations monitored in addition to the more conventional wastewater quality parameters. Results from pilot plant investigations demonstrated that of the four pilot upgrade series, the RF and AGM systems displayed the greatest treatment potential in terms of both the magnitude and reliability of suspended solids, algal and zooplankton biomass removals. The DW system was also shown to be at least as effective and in some instances significantly more advanced than the uncovered OP system in terms of its ability to significantly improve the final effluent quality of the Bolivar WSPs. Both the RF and AGM upgrades (and to a lesser degree also the DW system) were found to offer considerable potential for producing a higher quality WSP effluent for more efficient processing by the Bolivar DAF/F plant; although there were various operational advantages and disadvantages as well as varying capital establishment costs associated with each of the candidate technologies. This part of the research represented the first direct performance comparison between two popular pond upgrade technologies (i.e. RFs and DW) and also constituted the first assessment of a novel AGM for the upgrading of tertiary-level WSP effluent. In addition to this, results from ecological performance monitoring also provided the first detailed insights into algal and zooplankton population dynamics within these WSP upgrade environments. In addition to these pilot-scale WSP upgrade performance investigations, another branch of the research project investigated additional research questions regarding the survival of algal cells within these pond upgrade environments. A series of laboratory experiments attempted to recreate the in situ conditions (in terms of light and oxygen availability) that might exist within the adopted upgrade environments. Using two common WSP algal species, long-term monitoring of the physiological status of phytoplankton cells during prolonged dark-exposure under conditions of reduced oxygen availability was performed in order to assess the likely effects of these particular environmental conditions on their survival potential in situ. Results from these laboratory-based experiments showed that both algal species were capable of quickly adjusting their cellular metabolism in response to dark incubation. Results also showed that a reduced environmental oxygen concentration (25% of saturation) had no bearing on the ability of either Chlorella or Chlamydomonas species to withstand long-term dark-exposure; with both species retaining what was essentially full biological viability following up to two months of continuous dark-exposure. In an applied context, these results suggested that subjecting algal cells to conditions of simultaneous darkness and reduced oxygen availability would be expected to have no significant adverse effects on algal survivorship within an advanced in-pond upgrade system such as a duckweed-covered WSP, a rock filter or an AGM system.