Control of the tokamak safety factor profile with time-varying constraints using MPC

A controller is designed for the tokamak safety factor profile that takes real-time-varying operational and physics limits into account. This so-called model predictive controller (MPC) employs a prediction model in order to compute optimal control inputs that satisfy the given limits. The use of linearized models around a reference trajectory results in a quadratic programming problem that can easily be solved online. The performance of the controller is analysed in a set of ITER L-mode scenarios simulated with the non-linear plasma transport code RAPTOR. It is shown that the controller can reduce the tracking error due to an overestimation or underestimation of the modelled transport, while making a trade-off between residual error and amount of controller action. It is also shown that the controller can account for a sudden decrease in the available actuator power, while providing warnings ahead of time about expected violations of operational and physics limits. This controller can be extended and implemented in existing tokamaks in the near future.</p

roma westward migration in europe rethinking political social and methodological challenges

The idea for this book stemmed from two symposia that brought together scholars from a range of different countries and disciplines to reflect upon the political and legal context of the mobility of Romani citizens in Europe. Our interest in this topic started with the adoption of a EU Framework for National Roma Integration Strategies in 2011, when Member States were requested to develop integration strategies that were explicitly yet not exclusively targeted at their Roma populations (European Commission 2011). Even though this policy scheme represented an effort to overcome the inadequacies of the anti-discrimination directives to address the social and institutional discrimination suffered by Roma people in Europe, tangible results of such measures have so far been lacking. The symposia, titled "Roma Westward Migration in Europe: Rethinking Political, Social, and Methodological Challenges", addressed the emergence of Roma-specific policies alongside an increasing concern about migration and diversity management. The drive to bring together different disciplinary and methodological approaches to "Roma migration" in Europe, and to explore how such phenomenon has been narrated, policed, politicized or ignored was – and is – rooted in four main considerations. Firstly, we are convinced that putting the focus squarely on the so-called "Roma westward migration" and problematizing the assumptions that underpin such a label contributes to uncover the structural inconsistencies of the European "Roma integration" framework and to question its overall political approach. Secondly, the intersections and overlaps between the categories of "Roma" and of "migrants" show how the classifications of deservingness and of access to welfare resources have shifted in recent years, making explicit the under-studied link between inclusive and securitarian policies. Thirdly, we believe that "Roma migration" provides a unique testing ground to understand how those portrayed as "the others" in contemporary Europe cope and develop counter-strategies in a system in which their options are limited. Fourthly and finally, we strongly support ethnographic accounts as a useful means to evaluate public policies at the local level, as they offer rich data that cannot be captured by national statistics or by surveys alone

Gas phase characterization of the noncovalent quaternary structure of Cholera toxin and the Cholera toxin B subunit pentamer

Cholera toxin (CTx) is an AB5 cytotonic protein that has medical relevance in cholera and as a novel mucosal adjuvant. Here, we report an analysis of the noncovalent homopentameric complex of CTx B chain (CTx B5) using electrospray ionization triple quadrupole mass spectrometry and tandem mass spectrometry and the analysis of the noncovalent hexameric holotoxin usingelectrospray ionization time-of-flight mass spectrometry over a range of pH values that correlate with those encountered by this toxin after cellular uptake. We show that noncovalent interactions within the toxin assemblies were maintained under both acidic and neutral conditions in the gas phase. However, unlike the related Escherichia coli Shiga-like toxin B5 pentamer (SLTx B), the CTx B5 pentamer was stable at low pH, indicating that additional interactions must be present within the latter. Structural comparison of the CTx B monomer interface reveals an additional α-helix that is absent in the SLTx B monomer. In silico energy calculations support interactions between this helix and the adjacent monomer. These data provide insight into the apparent stabilization of CTx B relative to SLTx B

Ocean acidification and calcium carbonate saturation states in the coastal zone of the West Antarctic Peninsula

The polar oceans are particularly vulnerable to ocean acidification; the lowering of seawater pH and carbonate mineral saturation states due to uptake of atmospheric carbon dioxide (CO2). High spatial variability in surface water pH and saturation states (Ω) for two biologically-important calcium carbonate minerals calcite and aragonite was observed in Ryder Bay, in the coastal sea-ice zone of the West Antarctic Peninsula. Glacial meltwater and melting sea ice stratified the water column and facilitated the development of large phytoplankton blooms and subsequent strong uptake of atmospheric CO2 of up to 55 mmol m-2 day-1 during austral summer. Concurrent high pH (8.48) and calcium carbonate mineral supersaturation (Ωaragonite ~3.1) occurred in the meltwater-influenced surface ocean. Biologically-induced increases in calcium carbonate mineral saturation states counteracted any effects of carbonate ion dilution. Accumulation of CO2 through remineralisation of additional organic matter from productive coastal waters lowered the pH (7.84) and caused deep-water corrosivity (Ωaragonite ~0.9) in regions impacted by Circumpolar Deep Water. Episodic mixing events enabled CO2-rich subsurface water to become entrained into the surface and eroded seasonal stratification to lower surface water pH (8.21) and saturation states (Ωaragonite ~1.8) relative to all surface waters across Ryder Bay. Uptake of atmospheric CO2 of 28 mmol m-2 day-1 in regions of vertical mixing may enhance the susceptibility of the surface layer to future ocean acidification in dynamic coastal environments. Spatially-resolved studies are essential to elucidate the natural variability in carbonate chemistry in order to better understand and predict carbon cycling and the response of marine organisms to future ocean acidification in the Antarctic coastal zone

Minor Keywords of Political Theory: Migration as a Critical Standpoint. A collaborative project of collective writing

Coordinated and Edited by: N De Genova, M Tazzioli Co-Authored by: Claudia Aradau, Brenna Bhandar, Manuela Bojadzijev, Josue David Cisneros, N De Genova, Julia Eckert, Elena Fontanari, Tanya Golash-Boza, Jef Huysmans, Shahram Khosravi, Clara Lecadet, Patrisia Macías-Rojas, Federica Mazzara, Anne McNevin, Peter Nyers, Stephan Scheel, Nandita Sharma, Maurice Stierl, Vicki Squire, M Tazzioli, Huub van Baar and William Walter