Active particles using reinforcement learning to navigate in complex motility landscapes

As the length scales of the smallest technology continue to advance beyond the micron scale it becomes increasingly important to equip robotic components with the means for intelligent and autonomous decision making with limited information. With the help of a tabular Q-learning algorithm, we design a model for training a microswimmer, to navigate quickly through an environment given by various different scalar motility fields, while receiving a limited amount of local information. We compare the performances of the microswimmer, defined via time of first passage to a target, with performances of suitable reference cases. We show that the strategy obtained with our reinforcement learning model indeed represents an efficient navigation strategy, that outperforms the reference cases. By confronting the swimmer with a variety of unfamiliar environments after the finalised training, we show that the obtained strategy generalises to different classes of random fields

Coworking in NRW: Potenziale und Risiken von Coworking-Modellen für Berufspendlerinnen und -pendler, diskontinuierlich Beschäftigte und Personen mit familiärer Verantwortung

Im Forschungsvorhaben 'Coworking.NRW' wurde eine Bestandsaufnahme der Coworking-Büros in NRW und ihrer Arbeitsbedingungen erarbeitet. Dazu wurden eine Expertenbefragung (n=10), eine Online-Beschäftigtenbefragung (n=73), eine schriftliche Befragung von acht Coworking-Einrichtungen in NRW (von insgesamt 33 bekannten Einrichtungen zum Zeitpunkt der Erhebung) sowie vier vertiefende Fallstudien in Coworking-Büros durchgeführt. Untersucht wurden die Potenziale und Risiken des neuen Arbeitsmodells für die Zielgruppen der Berufspendler_innen, der Personen mit familiärer Verantwortung und der diskontinuierlich Beschäftigten. Auf dieser Grundlage wurden Handlungsempfehlungen für die weitere Entwicklung des Arbeitsmodells Coworking abgeleitet, um es auf diese Weise für die genannten Zielgruppen attraktiver zu machen.The research project 'Coworking.NRW' has prepared an overview of the state of the art of Northrhine-Westfalia's (NRW) coworking-offices and their working conditions. To gather relevant data, expert interviews (n=10), an online-survey (n=73) and a written survey of eight coworking spaces in NRW (out of 33 registered coworking spaces at the time of assessment) have been conducted. Furthermore, four coworking spaces have been analyzed in-depth as case-studies. Points of investigation have been potentials and risks of this new model of work for the target groups of commuters, workers with family responsibilities and discontinuously employed workers. On this basis, recommendations for a further development of the coworking-model have been formulated to attract the mentioned target-groups

Coworking in NRW: Potenziale und Risiken von Coworking-Modellen für abhängig Beschäftigte

Trotz des Potenzials für offene Kollaborationsund Innovationsprozesse wird Coworking derzeit überwiegend von innovationsintensiven, kreativen Branchen und Selbstständigen genutzt. Die bislang begrenzte (Markt-)Ausrichtung führt zu einem Lockin-Effekt und erschwert die Einbeziehung weiterer Zielgruppen. Eine Öffnung der Coworking-Spaces für weitere Zielgruppen erfordert die Weiterentwicklung des bisherigen Coworking-Modells. Durch zusätzliche Dienstleistungsangebote kann Coworking aus Sicht der Betreiber_innen und Nutzer_innen insbesondere für Berufspendler_innen, Erwerbstätige mit familiärer Verantwortung und im Homeoffice Beschäftigte eine attraktive Alternative werden. Handlungsempfehlung für NRW ist, speziell für Berufspendler_innen mit und ohne familiäre Verpflichtungen ein wohnortnahes Coworking-Modell zu fördern, das anspruchsvolle, motivierende und gesundheitsförderliche Arbeitsbedingungen bereitstellt

Der Bundestag im Verfassungsgefuege der Bundesrepublik Deutschland: Beitr. zum dreissigjaehrigen Bestehen d. Dt. Bundestages

Includes 33 articlesAvailable from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel B 209691 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Ocean/ice shelf interaction in the southern Weddell Sea: results of a regional numerical helium/neon simulation

Ocean/ice interaction at the base of deep drafted Antarctic ice shelves modifies the physical properties of inflowing shelf waters to become Ice Shelf Water (ISW).In contrast to the conditions at the atmosphere/ocean interface, the increased hydrostaticpressure at the glacial base causes gases embedded in the ice to solve completely after being released by melting. Helium and neon with an extremely low solubility are supersatured in glacial meltwater by more than 1000%. At the continentalslope in front of the large Antarctic caverns ISW mixes with ambient waters toform different precursors of Antarctic Bottom Water. A regional ocean circulation model is presented which uses an explicit formulation of the ocean/ice shelf interaction to describe for the first time the input of noble gases to the Southern Ocean. The results reveal a long-term variability of the basal mass loss solely controlled by the interaction between waters of the continental shelf and the ice shelf cavern. Modeled helium and neon supersaturations from the Filchner-Ronne Ice Shelf front reveal a "low-pass" filtering of the inflowing signal due to cavern processes. On circumpolar scales the helium and neon distributions in the Southern Ocean quantify the ISW contribution to bottom water which spreads with the coastal current connecting the major formation sites in Ross and Weddell Seas

Federação, democracia e instituições políticas Federation, democracy and political institutions

A questão do caráter federativo ou não de uma nação é inseparável da questão da descentralização das instituições políticas, sustenta-se. O tema é examinado com especial ênfase no papel que o sistema partidário desempenha nesse contexto.<br>It is argued that it is not possible to face the problem of federal organization without taking into account the question of the descentralization of the political institutions. The issue is examined with particular emphasis on the role played by the party system in this context

On the transport, variability and origin of dense water masses crossing the South Scotia Ridge

The deep Scotia Sea is filled with ventilated Weddell Sea Deep Water.This in turn is an essential contributor to the ventilation of the World Ocean abyss.Depending on the formation process and/or its location along the Weddell Seaperiphery, deep and bottom water masses follow different routes to crossthe South Scotia Ridge. A primitive equation, hydrostatic, terrain-followingcoordinate ocean general circulation model (BRIOS-1) is used to investigatethe water mass export from the Weddell Sea. The model is circumpolarfocusing on the Weddell Sea, with particulary high resolution (~ 20 km)in the DOVETAIL area. 24 Sv of eastward Weddell Sea Deep Watertransport is found in the northern limb of the Weddell Gyre across 44W.Export rates of Weddell Sea Deep Water through gaps in theSouth Scotia Ridge are estimated to 6.4 Sv with a semi-annual cycleof +- 0.6 Sv which can be correlated to atmospheric cyclone activity andWeddell Gyre strength.Sensitivity studies considering extreme sea ice conditions in the WeddellSea show higher (lower) exports in years of minimum (maximum) ice extent.Lagrangian particle trajectories illustrate the pathways of water massesfrom the inner Weddell Sea into the Scotia Sea through various gaps inthe South Scotia Ridge.They highlight the existing flow divergence on the northwestern continentalshelf with one branch entering Bransfield Strait and the other continuingeastwards subsequently filling the deep Scotia and Weddell seas.Water masses flowing through the major gaps originate from thesouthwestern and southeastern Weddell Sea continental shelves.However, water masses formed east of the Weddell Sea (e.g., Prydz Bay)also seem to feed the deep Scotia Sea, since a large portion of floatsflowing northward through the gaps of the South Scotia Ridge have beenin contact with the mixed layer processes outside the inner Weddell Sea