Numerical analysis of the flow past a Savonius wind turbine using Discrete Vortex Method in MATLAB.

Celem niniejszej pracy jest numeryczne przedstawienie przepływu wokół rotora Savoniusa na płaszczyźnie zespolonej oraz stworzenie kodu w programie MATLAB, w celu przewidywania wydajności aerodynamicznej turbiny. Geometria rotora na płaszczyźnie zespolonej, została przedstawiona przez dwa półkola, przemieszczone wzdłuż wspólnej średnicy. Założono wpływ lepkości wyłącznie do nieskończenie cienkiej warstwy płynu, stycznego do powierzchni łopat rotora. Warunki brzegowe Dirchleta, Neumana oraz prawo Kutty-Żukowskiego zostały wykorzystane w modelu matematycznym. Wyniki poddane zostały walidacji z danymi eksperymentalnymi innych badaczy oraz symulacją w programie ANSYS CFX dla analizowanej geometrii rotora.The aim of this paper is to numerically represent complex flow over a Savonius rotor and to develop a code in MATLAB software, for predicting its aerodynamic performance. Geometry of the rotor was represented in complex plane, by two semicircles, displaced along their common diameter. It was assumed that the influence of viscosity is confined to an infinitely thin layer of fluid adjacent to the surface of the rotor blades. The Dirichlet, Neuman boundary condition and Kutta Joukowsky condition have been used in the modelling. The results were validated by experimental data presented by other researchers and simulation performed in ANSYS CFX for analysed rotor geometry

The Limits of EUropean Legitimacy : On Populism and Technocracy. Introduction to the Special Issue

This article introduces the special issue on populism and technocracy in the integration and governance of the European Union (EU), framing these opposing approaches in the context of polarised debate on the (il)legitimacy of the EU. The special issue was conceived as an interdisciplinary approach to questions of the EU’s legitimacy in the aftermath of structural crises (the eurozone, sovereign debt and the election and appointment of governing agents) and spontaneous crises (migration, external state and non-state security challenges, Brexit and Euroscepticism). Since the special issue’s conception the unanticipated Covid-19 pandemic, and responses from the EU and its member states (current and former) starkly illuminated debates on how the EU should operate, the limits of its power and the limits of its popular legitimacy. The era of passive consensus has been replaced by claims of legitimacy based on active expert-informed intervention, alongside populist claims of the EU’s inherent illegitimacy as an undemocratic technocracy. As such the special issue’s objective is to critically analyse manifold ways in which the populist-technocratic divide is narrated and performed in different regions, disciplines, and social and political systems in an era of growing internal and external challenges to the Union. We observe that the EU’s institutions remain highly adaptable in responding to challenges, but that member-states have continued and accelerated a tendency to nationalise success and Europeanise failure, with the EU acting as a perennial scapegoat largely due to the ease with which it can be narrated as a site of projection for mistrust, resentment, and social grievances. We argue that the relationship between populism and technocracy is rapidly evolving from an imagined binary into a much more fluid, overlapping, and reversible set of political narratives. We conclude that despite the changing nature of populist-technocratic debates and the resilience and adaptability of the EU, it faces accelerating challenges to its legitimacy in the new era of ‘politics of necessity’

Nitrogen cost minimization is promoted by structural changes in the transcriptome of N-deprived Prochlorococcus cells

Prochlorococcus is a globally abundant marine cyanobacterium with many adaptations that reduce cellular nutrient requirements, facilitating growth in its nutrient-poor environment. One such genomic adaptation is the preferential utilization of amino acids containing fewer N-atoms, which minimizes cellular nitrogen requirements. We predicted that transcriptional regulation might further reduce cellular N budgets during transient N limitation. To explore this, we compared transcription start sites (TSSs) in Prochlorococcus MED4 under N-deprived and N-replete conditions. Of 64 genes with primary and internal TSSs in both conditions, N-deprived cells initiated transcription downstream of primary TSSs more frequently than N-replete cells. Additionally, 117 genes with only an internal TSS demonstrated increased internal transcription under N-deprivation. These shortened transcripts encode predicted proteins with an average of 21% less N content compared to full-length transcripts. We hypothesized that low translation rates, which afford greater control over protein abundances, would be beneficial to relatively slow-growing organisms like Prochlorococcus. Consistent with this idea, we found that Prochlorococcus exhibits greater usage of glycine-glycine motifs, which causes translational pausing, when compared to faster growing microbes. Our findings indicate that structural changes occur within the Prochlorococcus MED4 transcriptome during N-deprivation, potentially altering the size and structure of proteins expressed under nutrient limitation.Gordon and Betty Moore Foundation (Grant GBMF495)Simons Foundation (Award 329108)National Science Foundation (U.S.) (Grant DBI-0424599

The Common Oceanographer: Crowdsourcing the Collection of Oceanographic Data

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Thermoanaerosceptrum fracticalcis gen. nov. sp. nov., a novel fumarate-fermenting microorganism from a deep fractured carbonate aquifer of the US Great Basin

Deep fractured rock ecosystems across most of North America have not been studied extensively. However, the US Great Basin, in particular the Nevada National Security Site (NNSS, formerly the Nevada Test Site), has hosted a number of influential subsurface investigations over the years. This investigation focuses on resident microbiota recovered from a hydrogeologically confined aquifer in fractured Paleozoic carbonate rocks at 863 – 923 m meters below land surface. Analysis of the microorganisms living in this oligotrophic environment provides a perspective into microbial metabolic strategies required to endure prolonged hydrogeological isolation deep underground. Here we present a microbiological and physicochemical characterization of a deep continental carbonate ecosystem and describe a bacterial genus isolated from the ecosystem. Strain DRI-13T is a strictly anaerobic, moderately thermophilic, fumarate-respiring member of the phylum Firmicutes. This bacterium grows optimally at 55°C and pH 8.0, can tolerate a concentration of 100 mM NaCl, and appears to obligately metabolize fumarate to acetate and succinate. Culture-independent 16S rRNA gene sequencing indicates a global subsurface distribution, while the closest cultured relatives of DRI-13T are Pelotomaculum thermopropionicum (90.0% similarity) and Desulfotomaculum gibsoniae (88.0% similarity). The predominant fatty acid profile is iso-C15:0, C15:0, C16:0 and C14:0. The percentage of the straight-chain fatty acid C15:0 is a defining characteristic not present in the other closely related species. The genome is estimated to be 3,649,665 bp, composed of 87.3% coding regions with an overall average of 45.1% G+C content. Strain DRI-13T represents a novel genus of subsurface bacterium isolated from a previously uncharacterized rock-hosted geothermal habitat. The characterization of the bacterium combined with the sequenced genome provides insights into metabolism strategies of the deep subsurface biosphere. Based on our characterization analysis we propose the name Thermoanaerosceptrum fracticalcis (DRI-13T = DSM 100382T = ATCC TSD-12T)

Metabolic balance of coastal Antarctic waters revealed by autonomous pCO2 and ΔO2/Ar measurements

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 41 (2014): 6803–6810, doi:10.1002/2014GL061266.We use autonomous gas measurements to examine the metabolic balance (photosynthesis minus respiration) of coastal Antarctic waters during the spring/summer growth season. Our observations capture the development of a massive phytoplankton bloom and reveal striking variability in pCO2 and biological oxygen saturation (ΔO2/Ar) resulting from large shifts in community metabolism on time scales ranging from hours to weeks. Diel oscillations in surface gases are used to derive a high-resolution time series of net community production (NCP) that is consistent with 14C-based primary productivity estimates and with the observed seasonal evolution of phytoplankton biomass. A combination of physical mixing, grazing, and light availability appears to drive variability in coastal Antarctic NCP, leading to strong shifts between net autotrophy and heterotrophy on various time scales. Our approach provides insight into the metabolic responses of polar ocean ecosystems to environmental forcing and could be employed to autonomously detect climate-dependent changes in marine primary productivity.This study was supported by funds from the U.S. National Science Foundation (OPP awards ANT-0823101, ANT-1043559, ANT-1043593, and ANT-1043532) as well as support for PDT and ECA from the National Science and Engineering Research Council of Canada.2015-04-0

Resource limitation modulates the fate of dissimilated nitrogen in a dual-pathway Actinobacterium

Respiratory ammonification and denitrification are two evolutionarily unrelated dissimilatory nitrogen (N) processes central to the global N cycle, the activity of which is thought to be controlled by carbon (C) to nitrate (NO₃⁻) ratio. Here we find that Intrasporangium calvum C5, a novel menaquinone-based dual-pathway denitrifier/respiratory ammonifier, disproportionately utilizes ammonification rather than denitrification when grown under carbon or nitrate limitation, not C:NO3- ratio. Instead, C:NO₃⁻ ratio is a confounding variable for resource limitation. We find that the protein atomic composition for denitrification modules (NirK) are significantly cost minimized for C and N compared to ammonification modules (NrfA), indicating that resource limitation is a major selective pressure imprinted in the architecture of these proteins. The evolutionary precedent for these findings suggests ecological and biogeochemical importance as evidenced by higher growth rates when I. calvum grows predominantly using its ammonification pathway and by assimilating its end-product (ammonium) for growth under ammonium-deplete conditions. Genomic analysis of I. calvum further reveals a versatile ecophysiology to cope with nutrient stress and redox conditions. Metabolite and transcriptional profiles during growth indicate that transcript abundances encoding for its nitrite reducing enzyme modules, NrfAH and NirK, significantly increase in response to nitrite production. Mechanistically, our results suggest that pathway selection is driven by intracellular redox potential (redox poise), which may be lowered during resource limitation, thereby decreasing catalytic activity of upstream electron transport steps needed for denitrification enzymes. Our work advances our understanding of the biogeochemical flexibility of N-cycling organisms, pathway evolution, and ecological food-webs

A metagenomic assessment of winter and summer bacterioplankton from Antarctica Peninsula coastal surface waters

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in The ISME Journal 6 (2012): 1901-1915, doi:10.1038/ismej.2012.31.Antarctic surface oceans are well-studied during summer when irradiance levels are high, sea ice is melting and primary productivity is at a maximum. Coincident with this timing, the bacterioplankton respond with significant increases in secondary productivity. Little is known about bacterioplankton in winter when darkness and sea-ice cover inhibit photoautotrophic primary production. We report here an environmental genomic and small subunit ribosomal RNA (SSU rRNA) analysis of winter and summer Antarctic Peninsula coastal seawater bacterioplankton. Intense inter-seasonal differences were reflected through shifts in community composition and functional capacities encoded in winter and summer environmental genomes with significantly higher phylogenetic and functional diversity in winter. In general, inferred metabolisms of summer bacterioplankton were characterized by chemoheterotrophy, photoheterotrophy and aerobic anoxygenic photosynthesis while the winter community included the capacity for bacterial and archaeal chemolithoautotrophy. Chemolithoautotrophic pathways were dominant in winter and were similar to those recently reported in global ‘dark ocean’ mesopelagic waters. If chemolithoautotrophy is widespread in the Southern Ocean in winter, this process may be a previously unaccounted carbon sink and may help account for the unexplained anomalies in surface inorganic nitrogen content.CSR was supported by an NSF Postdoctoral Fellowship in Biological Informatics (DBI-0532893). The research was supported by National Science Foundation awards: ANT 0632389 (to AEM and JJG), and ANT 0632278 and 0217282 (to HWD), all from the Antarctic Organisms and Ecosystems Program

Scaling the mobility of health workers in an enlarged Europe : An open political-economy perspective

The final, definitive version of this paper has been published in European Urban and Regional Studies, Vol. 23 (4), October 2016, published by SAGE Publishing.The enlargement of the European Union in 2004 and 2007 and the marketisation of health care are increasing the mobility of workers and driving a scalar transformation of the sector across Europe. Drawing on questionnaires and interviews in 17 European Union countries, and focusing on two case study New Member States, we analyse inter- and intra-country drivers and impacts of health care labour mobility. The data are analysed from an open political-economy perspective underpinned by an understanding of scale as a socially constructed material entity mediated by national and supranational state institutions, and the collective agency of workers. We emphasise the contradictory and contested nature of rescaling health care and the complex micro-dynamics of mobility. Although absolute outward migration across borders is relatively small, the movement of health care specialists is having a disproportionate effect on sender countries and regions within them.Peer reviewedFinal Accepted Versio