Games with Delays. A Frankenstein Approach

We investigate infinite games on finite graphs where the information flow is perturbed by nondeterministic signalling delays. It is known that such perturbations make synthesis problems virtually unsolvable, in the general case. On the classical model where signals are attached to states, tractable cases are rare and difficult to identify. Here, we propose a model where signals are detached from control states, and we identify a subclass on which equilibrium outcomes can be preserved, even if signals are delivered with a delay that is finitely bounded. To offset the perturbation, our solution procedure combines responses from a collection of virtual plays following an equilibrium strategy in the instant- signalling game to synthesise, in a Frankenstein manner, an equivalent equilibrium strategy for the delayed-signalling game

KALMAR: "Kurile-Kamchatka and Aleutean Marginal Sea-Island Arc Systems: Geodynamic and Climate Interaction in Space and Time“ : an integrated Polar science approach between Russia and Germany

EGU2011-4204-1 The Russian German Cooperation in polar marine science has a long tradition. Since the last decade of the last century, there is a continous joint effort for geoscientific studies in the arctic and subarctic Far East. The new initiative of KALMAR II will concentrate on the complex geosystem of the Kurile-Kamchatka-Aleutean arc including the adjacent regions of the arctic Bering Sea and the NW Pacific. This giant and unique natural laboratory will allow the study of interactions and fluxes between the asthenosphere, the lithosphere, the hydrosphere, the cryosphere, and the atmosphere in order to provide detailed insights into natural risks (volcanic eruptions, tsunamis) and regional dynamics of the climate impacting on the global system. The envisaged integrated investigation will built upon the existing network of scientists from both countries who studied geodynamic and volcanologic as well paleoceanographic and paleoclimatic issues successfully in the past in the Far East. Two main research foci, ocean and climate dynamics as well as volcanisms and geodynamics, form the scientific backbone of the new KALMAR II initiative which will comprise in total five interlinked subprojects: Two subprojects will focus on the paleoclimatic and paleoceanographic evolution of this arctic region in relation to the development of the NW Pacific on millennial and decadal as well as seasonal times scales. This approach will test existing hypothesis with respect to water mass structure and water mass exchange through the Bering Strait, intermediate water mass formation, which, until know, is still not understood, marine productivity and their impact on the CO2 cycle, the glaciation history of Kamchatka and the continental oceanic (arctic) teleconnection between Atlantic and Pacific. The closely linked terrestrial subproject will study the marine influenced arctic region of Northern Kamchatka focusing on the geomorphologic and paleoclimatic evolution within the context of the northern hemisphere climate. One subproject within the volcanic and geodynamic focus will study experimentally petrologic and magmatic processes to better understand the evolution of magma and their volatiles in this volcanic arc system and how eruptions impact on the regional and global climate. Extremely linked to this subproject is the second one, which concentrates on the differentiation and alteration of volcanic rocks and their related volatile production. Special emphasis will be laid on fluid rock interactions in order to provide information about the input of fluids into the atmosphere and the hydrosphere. In a third aspect we envisage to study the origin of the volcanism within the western segment of the Aleutean Arc. This young volcanic activity ranging from Attu Island to Kamchatka was recently discovered from KALMAR scientists. The investigation of these volcanic rocks may reveal the transition from intraplate volcanism (North Kamchatka) to island arc volcanism (Attu Island) and may also shed light on the influence of the inclination of the subducting plate on the composition and intensity of the volcanic activity. All three magmatic and volcanological subprojects will use off shore as well as on shore material. To investigate the influence of major volcanic eruptions on the atmosphere and ocean, climate models will be employed

KALMAR - „Kurile-Kamchatka and Aleutean Marginal Sea-Island Arc Systems: Geodynamic and Climate Interaction in Space and Time” – an integrated science approach between Russia and Germany

EGU2010-2934 The exploration of the arctic seas require an integrated approach applying different infrastructures. In Fall 2009 German and Russian scientists performed a geo marine cruise off Kamchatka and in the western Bering Sea within the frame of the KALMAR-Project. Two main research subjects formed the scientific backbone of the cruise: The first objective focuses on the geodynamic and volcanological magmatic development of the Kuril-Kamchatka island arc system and the Kamchatka Aleutean Islands Triple-Junction. Very little is known about the composition of the mantle and the oceanic crust as well as of the seamounts including their ages. The best studied site is the Volcanologist’s Massif located between the Bering- and the Alpha Fracture Zone (Tsvetkov 1990, Volynets et al. 1992, Yogodzinsky et al. 1994), which structurally belongs to the Komandorsky Basin. The oldest rocks of the Volcanologist´s Massif show very similar trace element and isotope signatures like those rocks cropping out in the volcanoes on Kamchatka in the prolongation of the Alpha Fracture Zone (Portnyagin et al. 2005a), indicating similar conditions of magma formation. The top of the Volcanologist´s Massif is characterized by the young ( 85 Ma. The only existing basement rocks from this seamount were gained during DSDP Leg 19. These are basalts with MORB like trace element and isotope signatures (Keller et al. 2000, Regelous et al. 2003). These data indicate that the Hawaii-Hotspot was at a MOR in Cretaceous time and that large volumes of depleted mantle material played a´role during the magma formation. The second objective focuses on paleo-oceanographic investigations concentrating on the sediments along the eastern continental slope of Kamchatka, in the Komandorsky Basin, and on the Shirshov Ridge in order to explore paleoclimate archives to better understand the subpolar water mass transfer and the oceanographic and climatic development in the subarctic NW-Pacific. Comparisons of Late Pleistocene and Holocene temperature changes within the near surface water masses between the NW-Pacific and the N-Atlantic resulted in a new hypothesis, the "Atlantic-Pacific seesaw" (Kiefer et al. 2001, Kim et al. 2004, Kiefer and Kienast, 2005). This Atlantic-Pacific pattern of opposite temperature variations dominates the last 60ka on millennial timescales. Modelling results of Saenko et al. (2004) support the hypothesis of the "Atlantic-Pacific seesaw" and they postulate a mechanistic connection between the two regions driven by salinity variations, which couples both regions through the thermohaline circulation. A different model relates the Holocene Atlantic-Pacific dipole to the atmospheric tele-connection between the Arctic Oscillation/N-Atlantic Oscillation and the Pacific N-American Oscillation (Kim et al. 2004). http://kalmar.ifm-geomar.d

The origin of the Canary Island Seamount Province - New ages of old seamounts

The Canary Island Seamount Province forms a scattered hotspot track on the Atlantic ocean floor ,1300 km long and,350 km wide, perpendicular to lithospheric fractures, and parallel to theNWAfrican continental margin. New 40Ar/39Ar datings show that seamount ages vary from 133 Ma to 0.2 Ma in the central archipelago, and from 142 Ma to 91 Ma in the southwest. Combining 40Ar/39Ar ages with plate tectonic reconstructions, I find that the temporal and spatial distribution of seamounts is irreconcilable with a deep fixed mantle plume origin, or derivation from passive mantle upwelling beneath a mid-ocean ridge. I conclude that shallow mantle upwelling beneath the Atlantic Ocean basin off the NW African continental lithosphere flanks produced recurrent melting anomalies and seamounts from the Late Jurassic to Recent, nominating the Canary Island Seamount Province as oldest hotspot track in the Atlantic Ocean, and most long-lived preserved on earth

40Ar/39Ar ages of Pliocene-Pleistocene fallout tephra layers and volcaniclastic deposits in the sedimentary aprons of Gran Canaria and Tenerife (Sites 953, 954, and 956)

Six fallout tephra layers and 16 heterolithologic volcaniclastic deposits drilled at Holes 953A, 954A, 954B, and 956A, during Leg 157 in the sedimentary aprons of Gran Canaria and Tenerife, have been dated by single crystal laser 40Ar/39Ar analysis. The fallout tephra markers range in age from 0.273 ± 0.006 Ma to 2.74 ± 0.01 Ma. Maximum sedimentation ages determined for the volcaniclastic deposits range from 0.24 ± 0.01 Ma to 2.24 ± 0.02 Ma, closely matching the nannofossil and paleomagnetic chronostratigraphies of the cores. Both tephra and volcaniclastic layers represent material from Pliocene–Pleistocene explosive eruptions of the Cañadas Caldera (Tenerife), mixed with Miocene volcanic debris only in the holes drilled north of Gran Canaria (954A and 954B). Two fallout layers (0.61 ± 0.02 Ma and 1.83 ± 0.02 Ma) and five volcaniclastic deposits reflect explosive eruptions, which took place during postulated dormant stages of the Cañadas edifice

On the Complexity of SPEs in Parity Games

We study the complexity of problems related to subgame-perfect equilibria (SPEs) in infinite duration non zero-sum multiplayer games played on finite graphs with parity objectives. We present new complexity results that close gaps in the literature. Our techniques are based on a recent characterization of SPEs in prefix-independent games that is grounded on the notions of requirements and negotiation, and according to which the plays supported by SPEs are exactly the plays consistent with the requirement that is the least fixed point of the negotiation function. The new results are as follows. First, checking that a given requirement is a fixed point of the negotiation function is an NP-complete problem. Second, we show that the SPE constrained existence problem is NP-complete, this problem was previously known to be ExpTime-easy and NP-hard. Third, the SPE constrained existence problem is fixed-parameter tractable when the number of players and of colors are parameters. Fourth, deciding whether some requirement is the least fixed point of the negotiation function is complete for the second level of the Boolean hierarchy. Finally, the SPE-verification problem - that is, the problem of deciding whether there exists a play supported by a SPE that satisfies some LTL formula - is PSpace-complete, this problem was known to be ExpTime-easy and PSpace-hard