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Studies based on natural experiments find that consumption responds strongly and significantly to a transitory variation in income, while semistructural estimations find no pass-through of transitory shocks to consumption. I develop a more robust semistructural estimator that relaxes the assumption that log consumption is a random walk. The robust pass-through estimate is significant and large, implying a yearly marginal propensity to consume of 0.32, close to the natural experiment findings. The robust estimator performs well in numerical simulations of a life cycle model, while nonrobust estimators do not. The difference between the two in the simulations is similar to their difference in the survey data. (JEL D15, E21, J11)

SummaryDiatoms are photosynthetic unicellular microalgae that drive global ecological phenomena in the biosphere and are emerging sustainable feedstock for an increasing number of industrial applications. Diatoms exhibit enormous taxonomic and genetic diversity, which often result in peculiar biochemical and biological traits. Transposable elements (TE) represent a substantial portion of diatom genomes and have been hypothesized to exert a relevant role in enriching genetic diversity and centrally contribute to genome evolution. Here, through long-read whole genome sequencing, we identified a novel Mutator-Like Element (MULE) in the model diatomPhaeodactylum tricornutum,and we report the direct observation of its mobilization within the course of one single laboratory experiment. Under selective conditions, this novel TE inactivated theuridine monophosphate synthase(UMPS) geneof P. tricornutum,one of the two only endogenous genetic loci currently targeted for selectable auxotrophy in functional genetics and genome editing applications.We report the first, real-time observation of the mobilization of a transposon in diatoms that possesses novel peculiar features. These include the combined presence of a MULE transposase domain with Zinc finger, SWIM-type domains, and of a diatom-specific E3 ubiquitin ligase of the zinc finger UBR type, which indicate a novel mobilization mechanism. Our findings provide new elements for the understanding of the role of TEs in diatom genome evolution and in the enrichment of intraspecific genetic variability. Ultimately, this raises relevant concerns on the targeting of loci such asUMPSas selectable markers for functional genetics and biotechnological applications in diatoms.Significance StatementWe identified a novel DNA transposon in the diatomPhaeodactylum tricornutum. This new Mutator-Like Element encodes a transposase and a diatom-specific E3 ubiquitin ligase, which suggest a novel mobilization mechanism. We documented independent insertions in real-time, which spontaneously inactivated theuridine monophosphate synthase(UMPS) locus, a common selectable marker. We provide new insights on the role of transposons in diatom genome dynamics and evolution and on the unsuitability ofUMPSas selection locus in diatoms.

Unicellular microalgae are of immense ecological importance with growing commercial potential in industries such as renewable energy, food and pharmacology. Viral infections can have a profound impact on the growth and evolution of their hosts. However, very little is known of the diversity within, and effect of, unicellular microalgal RNA viruses. In addition, identifying RNA viruses in these organisms that could have originated more than a billion years ago constitutes a robust data set to dissect molecular events and address fundamental questions on virus evolution. We assessed the diversity of RNA viruses in eight microalgal cultures including representatives from the diatom, eustigmatophyte, dinoflagellate, red algae and euglenid groups. Using metatranscriptomic sequencing combined with bioinformatic approaches optimised to detect highly divergent RNA viruses, we identified ten RNA virus sequences, with nine constituting new viral species. Most of the newly identified RNA viruses belonged to the double-stranded Totiviridae, Endornaviridae and Partitiviridae, greatly expanding the reported host range for these families. Two new species belonging to the single-stranded RNA viral clade Marnaviridae, commonly associated with microalgal hosts, were also identified. This study highlights that a great diversity of RNA viruses likely exists undetected within the unicellular microalgae. It also highlights the necessity for RNA viral characterisation and to investigate the effects of viral infections on microalgal physiology, biology and growth, considering their environmental and industrial roles.ImportanceIn comparison to animals or plants, our knowledge of the diversity of RNA viruses infecting microbial algae – the microalgae – is minimal. Yet describing the RNA viruses infecting these organisms is of primary importance at both the ecological and economical levels because of the fundamental roles these organisms play in aquatic environments and their growing value across a range of industrial fields. Using metatranscriptomic sequencing we aimed to reveal the RNA viruses present in cultures of eight microalgae species belonging to the diatom, dinoflagellate, eustigmatophyte, rhodophyte and euglena major clades of algae. This work identified ten new divergent RNA virus species, belonging to RNA virus families as diverse as the double-stranded Totiviridae, Endornaviridae, Partitiviridae and the single-stranded Marnaviridae. By expanding the known diversity of RNA viruses infecting unicellular eukaryotes, this study contributes to a better understanding of the early evolution of the virosphere and will inform the use of microalgae in industrial applications.

In order to improve primary energy saving and reduce greenhouse emissions, vehicle integrated photovoltaics have an ongoing interest. Studies on the benefits from vehicle solar roof, which take into account all the losses and the monthly variation in different climate conditions, are required. Therefore, we developed a simulation tool of the mileage covered by VIPV. This tool takes into account various use profiles and different characteristics of the vehicles and of the PV system. Focusing on city bus, simulations show that many parameters influence the outputs of the model, mainly: the geographic location, the shading losses, the electric architecture and the battery saturation. With projections of the technology in 2030, VIPV cover up to 9739 km annual mileage. This represents up to 24 % of the total distance. For the best month, it can get up to 47 km/day. For average Europe case, with 30 % shading losses, the VIPV cover only 3711 km annual mileage. The upgrade of the technology from 2022 to 2030 improves the benefits of VIPV by approximately 34 %. Life cycle assessment of solar city bus shows neutral to high gains. The carbon footprint is up to 28 T CO2-equivalent avoided emissions on 20 years lifespan.

© 2019 The Royal Society of Chemistry. A hybrid process combining a single compartment aerobic membrane bioreactor (MBR) and a membrane microalgal reactor (MMR) was evaluated for nutrient removal and microalgal biomass production. When operated without biomass extraction, the microalgal biomass in the MMR reached 920 mg L-1 on day 18 and then collapsed, rendering nutrient removal ineffective. Stable operation of the MMR was achieved by regular biomass extraction (i.e. 1/30 of the microalgal biomass in the reactor daily). The biomass production at steady state was approximately 26 g m-3 d-1. The NO3- and PO43- uptake values by microalgae were 4.0 ± 1.1 and 1.5 ± 0.9 g m-3 d-1, respectively. A facile flocculation and separation technique capable of recovering 98% microalgal biomass was demonstrated. Although the hybrid process can significantly enhance nutrient removal and biomass production, further research is needed to intensify the microalgal growth rate. At the current microalgal growth rate, a large MMR volume (37 times that of the MBR) is necessary for synchronous operation.

© 2019 Elsevier Ltd This study investigated the impact of mixing on key factors including foaming, substrate stratification, methane production and microbial community in three full scale anaerobic digesters. Digester foaming was observed at one plant that co-digested sewage sludge and food waste, and was operated without mixing. The lack of mixing led to uneven distribution of total chemical oxygen demand (tCOD) and volatile solid (VS) as well as methane production within the digester. 16S rRNA gene-based community analysis clearly differentiated the microbial community from the top and bottom. By contrast, foaming and substrate stratification were not observed at the other two plants with internal circulation mixing. The abundance of methanogens (Methanomicrobia) at the top was about four times higher than at the bottom, correlating to much higher methane production from the top verified by ex-situ biomethane assay, causing foaming. This result is consistent with foaming potential assessment of digestate samples from the digester.

Today, an increasing number of companies are working with heterojunction technology because of its higher efficiency potential and decreasing LCOEs compared to traditional solar cells [1] [2]. One of the major challenges for SHJ solar cells is the use of low temperature silver paste for metallization because of 1) their lower conductivity and 2) their need of alternative interconnection strategies as described by Faes et. al. [2]. As heterojunction technology is relatively new and as new wafer sizes are about to be adopted, metallization and interconnection are facing challenges and opportunities [3]. To screen quickly the multiple possibilities, a specific modelling for heterojunction has to be developed. The parameters describing the metallization and interconnection of a module are numerous and highly interdependent. In this field, performance optimization is always a compromise to be made mainly between the additional series resistance of the elements (TCO, finger, busbar, ribbons) and their impact on the photo-generated current. Optimal results are expressed in term of finger width, grid pitch, number of busbar and ribbons, section of ribbons, etc. Even under standard conditions (STC), the optimizations are obviously dependent on the parameters of the non-metallized cell. Also, the results differ whether the optimization criterions include the cost of the individual elements (€/Wp). For these reasons, CTMOD, a multidimensional prediction model of the performance and material cost of each possible architecture, is essential.

In old age, consumption can fluctuate because of shocks to available resources and because health shocks affect utility from consumption. We find that even temporary drops in income and health are associated with drops in consumption and most of the effect of temporary drops in health on consumption stems from the reduction in the marginal utility from consumption that they generate. More precisely, after a health shock, richer households adjust their consumption of luxury goods because their utility of consuming them changes. Poorer households, instead, adjust both their necessary and luxury consumption because of changing resources and utility from consumption.

This work is devoted to the modeling and structural analysis of ventilation networks in small-scale mines using a physically oriented modeling method that ensures power conservation. Small-scale mines are common in the mineral extraction industry of underdeveloped countries and their physical characteristics are taken into account in the modeling process. The geometrical topology of the ventilation network in addition with the conservation laws of the fluid distribution along the network are considered in order to obtain a simple modeling methodology. Non-linear characteristics of the interconnected fluid dynamics represent a challenge to determine significant features of the system from a control point of view. Observability and controllability properties are analyzed by considering the structural systems approach. An structural analysis provides information based on the network topology independently of the mine parameters allowing the number of sensors and actuators to be reduced while also preserving the observability and controllability of the ventilation system. Experimental results are provided by building a small-scale ventilation network benchmark to evaluate the proposed model and its properties.

The chlorophyte microalga Chlorella vulgaris has been exploited within bioindustrial settings to treat wastewater and produce oxygen at the cathode of microbial fuel cells (MFCs), thereby accumulating algal biomass and producing electricity. We aimed to couple these capacities by growing C. vulgaris at the cathode of MFCs in wastewater previously treated by anodic bacteria. The bioelectrochemical performance of the MFCs was investigated with different catholytes including phosphate buffer and anode effluent, either in the presence or absence of C. vulgaris . The power output fluctuated diurnally in the presence of the alga. The maximum power when C. vulgaris was present reached 34.2 ± 10.0 mW m −2 , double that observed without the alga (15.6 ± 9.7 mW m −2 ), with a relaxation of 0.19 gL −1 d −1 chemical oxygen demand and 5 mg L −1 d −1 ammonium also removed. The microbial community associated with the algal biofilm included nitrogen-fixing ( Rhizobiaceae ), denitrifying ( Pseudomonas stutzeri and Thauera sp., from Pseudomonadales and Rhodocyclales orders, respectively), and nitrate-reducing bacteria ( Rheinheimera sp. from the Alteromonadales ), all of which likely contributed to nitrogen cycling processes at the cathode. This paper highlights the importance of coupling microbial community screening to electrochemical and chemical analyses to better understand the processes involved in photo-cathode MFCs.

Global water quantity and quality are anticipated to decrease in the coming decades, as a result of both increasing global populations and the effects of climate change. Reusing and recycling water is a key part of reducing the pressure on our existing water supplies and the aquatic environment. However, the occurrence of nonsteroidal anti-inflammatory drugs (NSAIDs) in secondary, and in some tertiary, treated effluents- and sewage-impacted water bodies is one of the major obstacles for the implementation of water reuse. For several decades, NSAIDs have been extensively used for therapeutic purposes in both humans and domestic livestock. The negative effects of NSAIDs on aquatic biota are just beginning to be realized. Currently, intensive treatments are required to remove effectively NSAIDs from recycled treated effluent in order to minimize or eliminate risks to human health and aquatic environment. In this chapter, we focus the discussion on contemporary methods for NSAID removal including biological, physical, chemical, and combined process that may provide a more effective and efficient alternative.

Mankind has recognized the value of land plants as renewable sources of food, medicine, and materials for millennia. Throughout human history, agricultural methods were continuously modified and improved to meet the changing needs of civilization. Today, our rapidly growing population requires further innovation to address the practical limitations and serious environmental concerns associated with current industrial and agricultural practices. Microalgae are a diverse group of unicellular photosynthetic organisms that are emerging as next-generation resources with the potential to address urgent industrial and agricultural demands. The extensive biological diversity of algae can be leveraged to produce a wealth of valuable bioproducts, either naturally or via genetic manipulation. Microalgae additionally possess a set of intrinsic advantages, such as low production costs, no requirement for arable land, and the capacity to grow rapidly in both large-scale outdoor systems and scalable, fully contained photobioreactors. Here, we review technical advancements, novel fields of application, and products in the field of algal biotechnology to illustrate how algae could present high-tech, low-cost, and environmentally friendly solutions to many current and future needs of our society. We discuss how emerging technologies such as synthetic biology, high-throughput phenomics, and the application of internet of things (IoT) automation to algal manufacturing technology can advance the understanding of algal biology and, ultimately, drive the establishment of an algal-based bioeconomy.

© 2019 Elsevier B.V. A simple, efficient, and fast settling flocculation technique to harvest microalgal biomass was demonstrated using a proprietary cationic polyacrylamide flocculant for a freshwater (Chlorella vulgaris) and a marine (Phaeodactylum tricornutum) microalgal culture at their mid-stationary growth phase. The optimal flocculant doses were 18.9 and 13.7 mg/g of dry algal biomass for C. vulgaris and P. tricornutum, respectively (equivalent to 7 g per m3 of algal culture for both species). The obtained optimal dose was well corroborated with changes in cell surface charge, and culture solution optical density and turbidity. At the optimal dose, charge neutralization of 64 and 86% was observed for C. vulgaris and P. tricornutum algal cells, respectively. Algae recovery was independent of the culture solution pH in the range of pH 6 to 9. Algal biomass recovery was achieved of 100 and 90% for C vulgaris and P. tricornutum respectively, and over 98% medium recovery was achievable by simple decanting.

© 2019 Elsevier B.V. Recent developed sequencing techniques have resulted in a new and unprecedented way to study biological wastewater treatment, in which most organisms are uncultivable. This review provides (i) an insight on state-of-the-art sequencing techniques and their limitations; (ii) a critical assessment of the microbial community in biological reactor and biofouling layer in a membrane bioreactor (MBR). The data from high-throughput sequencing has been used to infer microbial growth conditions and metabolisms of microorganisms present in MBRs at the time of sampling. These data shed new insight to two fundamental questions about a microbial community in the MBR process namely the microbial composition (who are they?) and the functions of each specific microbial assemblage (what are their function?). The results to date also highlight the complexity of the microbial community growing on MBRs. Environmental conditions are dynamic and diverse, and can influence the diversity and structural dynamics of any given microbial community for wastewater treatment. The benefits of understanding the structure of microbial communities on three major aspects of the MBR process (i.e. nutrient removal, biofouling control, and micropollutant removal) were symmetrically delineated. This review also indicates that the deployment of microbial community analysis for a practical engineering context, in terms of process design and system optimization, can be further realized.

© 2019 Elsevier B.V. Terpenoids are a large and diverse class of naturally occurring metabolites serving many industrial applications and natural roles. Economically important terpenoids are often produced in low abundance from their natural sources, making their industrial-scale production challenging or uneconomical, therefore engineered microorganisms are frequently used as heterologous production platforms. Photosynthetic microorganisms, such as the green alga Chlamydomonas reinhardtii, represent promising systems to produce terpenoids in a cost-effective and sustainable manner, but knowledge about the regulation of their terpenoid metabolism remains limited. Here we report on the investigation of the phytohormone methyl jasmonate (MeJA) as elicitor of algal terpenoid synthesis. We treated C. reinhardtii cells in mid-exponential growth phase with three different concentrations of MeJA (0.05, 0.5 and 1 mM). The highest concentration of MeJA affected the photosynthetic activity of the cells, arrested the growth and up-regulated key genes of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, leading to a significant increase in intermediates of this pathway, squalene and (S)-2,3-epoxysqualene, while the abundance of cycloartenol, and two main sterols (ergosterol and 7-dehydroporiferasterol) decreased. These data suggest the redirection of the carbon flux towards the synthesis of yet uncharacterised triterpenoid secondary metabolites upon MeJA treatment. Our results offer important new insights into the regulation of the triterpenoid metabolism in C. reinhardtii and raise important questions on hormonal signalling in microalgae. Phytohormone treatment is tested for the first time in algae, where it holds great potential for identifying key transcriptional regulators of the MEP pathway as targets for future metabolic engineering studies for improve production of high-value triterpenoids.

© 2019 Elsevier Ltd Activated sludge (AS) and return activated sludge (RAS) microbial communities from three full-scale municipal wastewater treatment plants (denoted plant A, B and C) were compared to assess the impact of sludge settling (i.e. gravity thickening in the clarifier) and profile microorganisms responsible for nutrient removal and reactor foaming. The results show that all three plants were dominated with microbes in the phyla of Proteobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria, Chloroflexi, Firmicutes, Nitrospirae, Spirochaetae, Acidobacteria and Saccharibacteria. AS and RAS shared above 80% similarity in the microbial community composition, indicating that sludge thickening does not significantly alter the microbial composition. Autotrophic and heterotrophic nitrifiers were present in the AS. However, the abundance of autotrophic nitrifiers was significantly lower than that of the heterotrophic nitrifiers. Thus, ammonium removal at these plants was achieved mostly by heterotrophic nitrification. Microbes that can cause foaming were at 3.2% abundance, and this result is well corroborated with occasional aerobic biological reactor foaming. By contrast, these microbes were not abundant (

The commercialisation of valuable plant triterpenoids faces major challenges, including low abundance in natural hosts and costly downstream purification procedures. Endeavours to produce these compounds at industrial scale using microbial systems are gaining attention. Here, we report on a strategy to enrich the biomass of the biotechnologically-relevant Chlamydomonas reinhardtii strain UVM4 with valuable triterpenes, such as squalene and (S)-2,3-epoxysqualene. C. reinhardtii UVM4 was subjected to the elicitor compounds methyl jasmonate (MeJA) and methyl-β-cyclodextrine (MβCD) to increase triterpene yields. MeJA treatment triggered oxidative stress, arrested growth, and altered the photosynthetic activity of the cells, while increasing squalene, (S)-2,3-epoxysqualene, and cycloartenol contents. Applying MβCD to cultures of C. reinhardtii lead to the sequestration of the two main sterols (ergosterol and 7-dehydroporiferasterol) into the growth medium and the intracellular accumulation of the intermediate cycloartenol, without compromising cell growth. When MβCD was applied in combination with MeJA, it counteracted the negative effects of MeJA on cell growth and physiology, but no synergistic effect on triterpene yield was observed. Together, our findings provide strategies for the triterpene enrichment of microalgal biomass and medium.

This study aims to examine the flocculation efficiency of Porphyridium purpureum (i.e. a red marine microalga with high content of pigments and fatty acids) grown in seawater medium using polyacrylamide polymers and alkaline flocculation. Polymers Flopam™ and FO3801 achieved the highest flocculation efficiency of over 99% at the optimal dose of 21 mg per g of dry biomass through charge neutralisation and bridging mechanism. The addition of sodium hydroxide, potassium hydroxide, and sodium carbonate also achieved flocculation efficiency of 98 and 91%, respectively, but high doses were required (i.e. > 500 mg per g of dry biomass). Calcium hydroxide was not as effective and could only achieve 75% flocculation efficiency. Precipitation of magnesium hydroxide was identified as the major cause of hydroxide-induced flocculation. On the other hand, sodium carbonate addition induced flocculation via both magnesium and calcium carbonate co-precipitation. The large mass of precipitates caused a sweeping effect and enmeshed the microalgal cells to trigger sedimentation. Cell membrane integrity analysis of flocculated P. purpureum indicated that polyacrylamide polymers led to significant compromised cells (i.e. 96%), compared to the alkaline bases (70–96% compromised cells). These results appear to be the first to demonstrate the high efficiency of polyacrylamide polymer and alkaline flocculation of P. purpureum but at the expense of the biomass quality.

© 2016. The microalga Nannochloropsis oculata is a model organism for understanding intracellular lipid production, with potential benefits to the biofuel, aquaculture and nutraceutical industries. It is well known that nitrogen deprivation increases lipid accumulation in microalgae but the underlying processes are not fully understood. In this study, detailed proteomic and biophysical analyses were used to describe mechanisms that regulate carbon partitioning in nitrogen-deplete N. oculata. The alga selectively up- or down-regulated proteins to shift its metabolic flux in order to compensate for deficits in nitrate availability. Under nitrogen deprivation, proteins involved in photosynthesis, carbon fixation and chlorophyll biosynthesis were all down-regulated, and this was reflected in reduced cell growth and chlorophyll content. Protein content was reduced 4.9-fold in nitrogen-deplete conditions while fatty acid methyl esters increased by 60%. Proteomic analysis revealed that organic carbon and nitrogen from the breakdown of proteins and pigments is channeled primarily into fatty acid synthesis. As a result, the fatty acid concentration increased and the fatty acid profile became more favorable for algal biodiesel production. This advancement in microalgal proteomic analysis will help inform lipid accumulation strategies and optimum cultivation conditions for overproduction of fatty acids in N. oculata.

The biochemical oxygen demand (BOD) of a given water sample is typically measured using a conventional BOD 5 assay, which requires 5 days of incubation at 20 °C of the sample with mixed communities of bacteria. The study presents a new type of BOD sensor using a Geobacter -dominated biofilm selected with ethanol as the sole carbon source. Ethanol selected for biofilms with a broader substrate usage than those selected with acetate, making them better for BOD biosensing applications. The biosensor was operated at room temperature with a voltage input of −0.08 V vs SHE (−0.36 V vs Ag/AgCl) and calibrated using several dilutions of synthetic wastewater with known BOD concentrations ranging from 174 mg/L to 1200 mg/L. The charge transferred by the biofilm over a reaction time of 17.5 h was linearly correlated ( R 2 = 0.96) with BOD. Once calibrated, the biosensor was used to measure the BOD of cow’s milk with a reproducibility of 94% and an error of only 7.4% compared to BOD 5 values. In contrast to the 5 days incubation currently required by standard BOD methods our novel biosensor offers a rapid monitoring alternative for assessments of the BOD of dairy effluent.

Microalgae are increasingly being considered for recombinant protein production because of low cultivation costs, absence of endotoxins and insusceptibility to human infectious agents. Despite these advantages, the yield of recombinant protein produced in microalgae is still low compared to more established expression systems and optimization at the genetic and cultivation levels is required for this new system to be economically viable. This study investigates the effect of biphasic temperature regimes on the yield of recombinant human interferon alpha 2a (IFN-α2a), a therapeutic protein known for its anti-cancer and anti-viral properties, produced by the model green alga Chlamydomonas reinhardtii (Cr.IFN-α2a). Biphasic growth is commonly employed to increase recombinant protein production in mammalian cell lines used for commercial production of therapeutic proteins, with a lowering of the temperature resulting in higher yields. In this study, lowering the temperature from 25 °C to 15 °C in mid-exponential growth phase increased the accumulation of Cr.IFN-α2a by 3.3-fold while it slowed down the growth of the three C. reinhardtii transgenic lines tested. In contrast, a rise of temperature from 25 °C to 35 °C accelerated cell growth, while negatively impacting the production of Cr.IFN-α2a. After a two-step chromatography purification, the Cr.IFN-α2a produced was estimated to be 53% pure with a yield of 90 μg/L of culture. The amino acid sequence of Cr.IFN-α2a was confirmed by mass spectrometry. However, the anti-viral activity of Cr.IFN-α2a was found to be 10 times lower than the human IFN-α2a standard produced using E. coli when challenged in a cytopathic effect (CPE) assay, likely due to the formation of aggregates. While the molecular mechanisms driving the accumulation of Cr.IFN-α2a at lower temperature remains unclear, our results support that reducing the temperature at the peak of expression is a valid strategy to increase the yield of recombinant Cr.IFN-α2a in C. reinhardtii.

International audience; In this paper, we consider dynamical graph-based systems, which are well fitted for the structural analysis of complex systems. A significant amount of work has been devoted to the controllability of such graph based systems, e.g. for multi-agent systems or complex networks. We study here the controllability through input addition in this framework. We present several variants of this problem depending on the freedom which is left to the designer on the additional inputs. Our contribution lies in the minimal number of inputs to be added for controllability. We provide also with information on the possible location of additional inputs. We finally present some links with other approaches and we show that these results can be easily applied to complex systems.

Terpenoids are a large and diverse class of naturally occurring metabolites serving many industrial applications and natural roles. Economically important terpenoids are often produced in low abundance from their natural sources, making their industrial-scale production challenging or uneconomical, therefore engineered microorganisms are frequently used as heterologous production platforms. Photosynthetic microorganisms, such as the green alga Chlamydomonas reinhardtii, represent promising systems to produce terpenoids in a cost-effective and sustainable manner, but knowledge about the regulation of their terpenoid metabolism remains limited. Here we report on the investigation of the phytohormone methyl jasmonate (MeJA) as elicitor of algal terpenoid synthesis. We treated C. reinhardtii cells in mid-exponential growth phase with three different concentrations of MeJA (0.05, 0.5 and 1 mM). The highest concentration of MeJA affected the photosynthetic activity of the cells, arrested the growth and up-regulated key genes of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, leading to a significant increase in intermediates of this pathway, squalene and (S)-2,3-epoxysqualene, while the abundance of cycloartenol, and two main sterols (ergosterol and 7-dehydroporiferasterol) decreased. These data suggest the redirection of the carbon flux towards the synthesis of yet uncharacterised triterpenoid secondary metabolites upon MeJA treatment. Our results offer important new insights into the regulation of the triterpenoid metabolism in C. reinhardtii and raise important questions on hormonal signalling in microalgae. Phytohormone treatment is tested for the first time in algae, where it holds great potential for identifying key transcriptional regulators of the MEP pathway as targets for future metabolic engineering studies for improve production of high-value triterpenoids.

In this paper we consider linear systems with faults. We present a new system decomposition well suited for sensor location in the Fault Detection and Isolation problem. We deal with this problem when the system under consideration is structured, that is, the entries of the system matrices are either fixed zeros or free parameters. To such structured systems one can associate a graph. We present a structural decomposition of this graph which extends previous results. This decomposition is based on the analysis of particular separators. This finer structural decomposition allows to characterize all the solutions in terms of location of possible additional sensors.

L'etude a l'aide de graphes des proprietes des systemes dynamiques qui dependent essentiellement de leur structure, permet de resoudre de maniere simple et pedagogique de nombreux problemes d'observation et de commande. On donne un apercu des differentes approches structurelles et on se focalise plus particulierement sur les modeles a base de composants qui sont tres utiles pour la conception de systemes fiables. On developpe a partir du treillis associe, des outils pour l'evaluation de la tolerance aux fautes des systemes consideres et pour une propriete donnee. En particulier des mesures d'utilite des composants sont donnees pour des proprietes a satisfaire telles que l'observabilite ou la tolerance aux fautes de certaines proprietes. L'evaluation de l'importance de ces composants permet de decider de leur politique de maintenance ou de leur eventuelle duplication.

International audience; In this paper, we consider dynamical graph-based models, which are well fitted for the structural analysis of complex systems. A significant amount of work has been devoted to the controllability of such graph based models, {\em e.g.} recently for multi-agent systems or complex networks. We study here the controllability through input addition in this framework. We present several variants of this problem depending on the freedom which is left to the designer on the additional inputs. We use a unified framework, which allows to encompass the different applications and representations (large scale systems, complex communications networks, multi-agent systems, ...) and provide with convenient graph tools for their analysis. Our contribution is to characterize the structural modifications of the system resulting from an input addition (or a leader selection) and of the mechanisms which lead to controllability. We provide with information on the possible location of additional inputs and on the minimal number of inputs to be added for controllability.

© 2016 Elsevier Ltd Seagrasses are important marine foundation species, which are presently threatened by coastal development and global change worldwide. The molecular mechanisms that drive seagrass responses to anthropogenic stresses, including elevated levels of nutrients such as ammonium, remains poorly understood. Despite the evidence that seagrasses can assimilate ammonium by using glutamine synthetase (GS)/glutamate synthase (glutamine-oxoglutarate amidotransferase or GOGAT) cycle, the regulation of this fundamental metabolic pathway has never been studied at the gene expression level in seagrasses so far. Here, we combine (i) reverse transcription quantitative real-time PCR (RT-qPCR) to measure expression of key genes involved in the GS/GOGAT cycle, and (ii) stable isotope labelling and mass spectrometry to investigate 15N-ammonium assimilation in the widespread Australian species Zostera muelleri subsp. capricorni (Z. muelleri). We demonstrate that exposure to a pulse of ammonium in seawater can induce changes in GS gene expression of Z. muelleri, and further correlate these changes in gene expression with 15N-ammonium uptake rate in above- and below-ground tissue.

In this paper we first study observability conditions on networks. Based on spectral properties of graphs, we state new sufficient or necessary conditions for observability. These conditions are based on properties of the Khatri-Rao product of matrices. Then we consider the problem of estimating the eigenvalues of the Laplacian matrix associated with the graph modeling the interconnections between the nodes of a given network. Eventually, we extend the study to the identification of the network topology by estimating both eigenvalues and eigenvectors of the network matrix. In addition, we show how computing, in finite-time, some linear functionals of the state initial condition, including average consensus. Specifically, based on properties of the observability matrix, we show that Laplacian eigenvalues can be recovered by solving a local eigenvalue decomposition on an appropriately constructed matrix of observed data. Unlike FFT based methods recently proposed in the literature, in the approach considered herein, we are also able to estimate the multiplicities of the eigenvalues. Then, for identifying the network topology, the eigenvectors are estimated by means of a consensus-based least squares method.

Good veterinary governance assumes the provision of veterinary services that are sustainably financed, universally available, and provided efficiently without waste or duplication, in a manner that is transparent and free of fraud or corruption. Good veterinary governance is a necessary condition for sustainable economic development insomuch as it promotes the effective delivery of services and improves the overall performance of animal health systems. This article defines governance in Veterinary Services and proposes a framework for its measurement. It also discusses the role of Veterinary Services and analyses the governance dimensions of the performance-assessment tools developed by the World Organisation for Animal Health (OIE). These tools (OIE PVS Tool and PVS Gap Analysis) track the performance of Veterinary Services across countries (a harmonised tool) and over time (the PVS Pathway). The article shows the usefulness of the OIE PVS Tool for measuring governance, but also points to two shortcomings, namely (i) the lack of clear outcome indicators, which is an impediment to a comprehensive assessment of the performance of Veterinary Services, and (ii) the lack of specific measures for assessing the extent of corruption within Veterinary Services and the extent to which demand for better governance is being strengthened within the animal health system. A discussion follows on the drivers of corruption and instruments for perception-based assessments of country governance and corruption. Similarly, the article introduces the concept of social accountability, which is an approach to enhancing government transparency and accountability, and shows how supply-side and demand-side mechanisms complement each other in improving the governance of service delivery. It further elaborates on two instruments--citizen report card surveys and grievance redress mechanisms--because of their wider relevance and their possible applications in many settings, including Veterinary Services. Also, central to improving transparency and accountability is access to information and a discussion on the appropriate level of decentralisation of Veterinary Services. Bringing Veterinary Services into compliance with OIE international standards would contribute to improving governance and providing economic benefits through increased animal productivity, the expansion of trade and improved food security. It would also help to increase public health benefits, through greater food safety and better prevention and control of zoonoses.

SUMMARY The lattice of component subsets is a very useful structure for addressing fault tolerance and architecture design problems for systems described as a set of components. This paper presents a number of concepts and techniques that are associated with this lattice to evaluate the degree of fault tolerance of a given property and to classify components with respect to their usefulness for this property. Being very general, the approach needs no assumption on the system, nor on the properties to be satisfied, and allows both deterministic and probabilistic measures to be used. A sensor selection example illustrates the practical use of the proposed tools. Copyright © 2011 John Wiley & Sons, Ltd.

We consider here the fault detection and isolation (FDI) problem for linear systems. We are interested in designing a set of observer-based residuals, in such a way that the transfer from the faults to the residuals is diagonal and the transfer from the disturbances to the residuals is zero. We deal with this problem when the system under consideration is structured, that is, the entries of the system matrices are either fixed zeros or free parameters. This problem can be solved in terms of the graph that can be associated in a natural way with a structured system. When the FDI solvability conditions are not satisfied, we assume that internal variables can be measured at a cost and look into the question of wether the problem is solvable with these new measurements. We give solvability conditions for a solution with a minimal number of additional sensors and among such solutions provide a minimal cost solution for the sensor location problem under consideration. We pay particular attention to the internal analysis of the system, and we propose a structural decomposition of the system associated graph based on some particular separators. This analysis leads to the definition of a reduced system. We prove that some potential additional sensors are inefficient for solving our FDI problem and that the FDI problem can be solved using only measurements on the reduced system

International audience; In this paper, we consider dynamical graph-based systems, which are well fitted for the structural analysis of complex systems. A significant amount of work has been devoted to the controllability of such graph-based systems with application to multi-agent systems or complex networks. We give a refined analysis of the controllability through control input addition in this framework. We provide with information on the possible location of additional inputs and give tight bounds on the number of inputs to be added for controllability. These results can be easily applied to complex systems.

© 2015 Elsevier Ltd. All rights reserved. This study evaluated the impact of inoculum source and anode surface modification (carboxylate -COO- and sulfonamide -SO2NH2 groups) on the microbial composition of anode-respiring biofilms. These two factors have not previously been considered in detail. Three different inoculum sources were investigated, a dry aerobic soil, brackish estuarine mud and freshwater sediment. The biofilms were selected using a poised anode (-0.36 V vs Ag/AgCl) and acetate as the electron donor in a three-electrode configuration microbial fuel cell (MFC). Population profiling and cloning showed that all biofilms selected were dominated by Geobacter sp., although their electrochemical properties varied depending on the source inoculum and electrode surface modification. These findings suggest that Geobacter sp. are widespread in soils, even those that do not provide a continuously anaerobic environment, and are better at growing in the MFC conditions than other bacteria.

© 2015 Elsevier B.V. Geobacter-dominated biofilms can be selected under stringent conditions that limit the growth of competing bacteria. However, in many practical applications, such stringent conditions cannot be maintained and the efficacy and stability of these artificial biofilms may be challenged. In this work, biofilms were selected on low-potential anodes (-0.36V vs Ag/AgCl, i.e. -0.08V vs SHE) in minimal acetate or ethanol media. Selection conditions were then relaxed by transferring the biofilms to synthetic wastewater supplemented with soil as a source of competing bacteria. We tracked community succession and functional changes in these biofilms. The Geobacter-dominated biofilms showed stability in their community composition and electrochemical properties, with Geobacter sp. being still electrically active after six weeks in synthetic wastewater with power densities of 100±19mW·m-2 (against 74±14mW·m-2 at week 0) for all treatments. After six weeks, the ethanol-selected biofilms, despite their high taxon richness and their efficiency at removing the chemical oxygen demand (0.8g·L-1 removed against the initial 1.3g·L-1 injected), were the least stable in terms of community structure. These findings have important implications for environmental microbial fuel cells based on Geobacter-dominated biofilms and suggest that they could be stable in challenging environments.

This paper deals with the performance evaluation of a linear network made of several routers separated by finite buffers with data traffic without flow control. By using a continuous flow model for the line, Markovian models can be developed for two routers lines but the complete model of a line composed by several routers is too complicated to use an analytical method. We then use some assumptions on the independence of random variables to build tractable approximative Markovian models. More specifically, we decompose the line in a series of two-routers lines, which is easier to study. The idea is borrowed from the approximative methods for performance evaluation of continuous flows for production lines [DAL 89].

In this paper we consider linear systems with disturbances and faults. We present a system decomposition well suited for the Fault Detection and Isolation problem. We deal with this problem when the system under consideration is structured, that is, the entries of the system matrices are either fixed zeros or free parameters. To such structured systems one can associate a graph. Many system structural properties can be deduced from the analysis of disjoint sets of input-output paths, called linkings, in the graph. The partition of such maximal linkings will lead to a new graph-based system decomposition. This structural decomposition exhibits the set of faults which can be detected and isolated thanks to the existing sensors and also the desirable location of possible additional sensors.

In this paper, a new encoding strategy is proposed for data exchange through limited bandwidth communication networks. The proposed strategy belongs to the family of finitely recursive equal-partition schemes. Convergence results are proposed under bounded measurement noises. When the noise probability density function is known, heuristic procedure is proposed to optimize the encoding scheme’s parameters. This is done using the discrete-time Markov chains tool. Simulations may be viewed at http://www.lag.ensieg.inpg.fr/alamir/Network.electrics/alamir_commault.pdf

In this paper we consider discrete-time linear positive systems, that is systems defined by a pair (A,B) of non-negative matrices. We study the reachability of such systems which in this case amounts to the freedom of steering the state in the positive orthant by using non-negative control sequences. This problem was solved recently [Canonical forms for positive discrete-time linear control systems, Linear Algebra Appl., 310 (2000) 49]. However we derive here necessary and sufficient conditions for reachability in a simpler and more compact form. These conditions are expressed in terms of particular paths in the graph which is naturally associated with the system.

In this paper we consider linear structured systems which represent a large class of parameter-dependent linear systems and we study invariants for such systems under a large group of transformations including state feedback. In this context we consider the dimension of the maximal output-nulling invariant subspace of a linear structured system, the number and structure of its invariant zeros and its structure at infinity. We give generic characterizations of the invariants in terms of properties of the directed graph that can be naturally associated with a linear structured system.

In this survey paper, we consider linear structured systems in state space form, where a linear system is structured when each entry of its matrices, like A,B,C and D, is either a fixed zero or a free parameter. The location of the fixed zeros in these matrices constitutes the structure of the system. Indeed a lot of man-made physical systems which admit a linear model are structured. A structured system is representative of a class of linear systems in the usual sense. It is of interest to investigate properties of structured systems which are true for almost any value of the free parameters, therefore also called generic properties. Interestingly, a lot of classical properties of linear systems can be studied in terms of genericity. Moreover, these generic properties can, in general, be checked by means of directed graphs that can be associated to a structured system in a natural way. We review here a number of results concerning generic properties of structured systems expressed in graph theoretic terms. By properties we mean here system-specific properties like controllability, the finite and infinite zero structure, and so on, as well as, solvability issues of certain classical control problems like disturbance rejection, input-output decoupling, and so on. In this paper, we do not try to be exhaustive but instead, by a selection of results, we would like to motivate the reader to appreciate what we consider as a wonderful modelling and analysis tool. We emphasize the fact that this modelling technique allows us to get a number of important results based on poor information on the system only. Moreover, the graph theoretic conditions are intuitive and are easy to check by hand for small systems and by means of well-known polynomially bounded combinatorial techniques for larger systems.

In this paper we consider phase-type distributions. These distributions correspond to the random hitting time of an absorbing Markov chain. They are used for modelling various random times, in particular, those which appear in manufacturing systems as processing times, times to failure, repair times, etc. The Markovian nature of these distributions allows the use of very efficient matrix based computer methods for performance evaluation. In this paper we give a system theory oriented introduction to phase-type distributions. We concentrate mainly on the representation problem which consists of finding a Markov chain associated with some phase-type distribution. This is a realization problem in the sense of system theory with a lot of links with the classical linear system theory but also with a number of constraints which make the problem harder but more interesting. Indeed this problem has strong connections with the positive realization problem in control theory. The paper recalls known results, gives s...