Separations of Non-monotonic Randomness Notions

In the theory of algorithmic randomness, several notions of random sequence are defined via a game-theoretic approach, and the notions that received most attention are perhaps Martin-L"of randomness and computable randomness. The latter notion was introduced by Schnorr and is rather natural: an infinite binary sequence is computably random if no total computable strategy succeeds on it by betting on bits in order. However, computably random sequences can have properties that one may consider to be incompatible with being random, in particular, there are computably random sequences that are highly compressible. The concept of Martin-L"of randomness is much better behaved in this and other respects, on the other hand its definition in terms of martingales is considerably less natural. Muchnik, elaborating on ideas of Kolmogorov and Loveland, refined Schnorr\u27s model by also allowing non-monotonic strategies, i.e. strategies that do not bet on bits in order. The subsequent ``non-monotonic\u27\u27 notion of randomness, now called Kolmogorov-Loveland-randomness, has been shown to be quite close to Martin-L"of randomness, but whether these two classes coincide remains a fundamental open question. In order to get a better understanding of non-monotonic randomness notions, Miller and Nies introduced some interesting intermediate concepts, where one only allows non-adaptive strategies, i.e., strategies that can still bet non-monotonically, but such that the sequence of betting positions is known in advance (and computable). Recently, these notions were shown by Kastermans and Lempp to differ from Martin-L"of randomness. We continue the study of the non-monotonic randomness notions introduced by Miller and Nies and obtain results about the Kolmogorov complexities of initial segments that may and may not occur for such sequences, where these results then imply a complete classification of these randomness notions by order of strength

Two-stage high pressure anaerobic digestion for biomethane production

The use of natural gas for power and heat generation in the EU has become particularly prominent since the 1990s. As a result, the whole natural gas infrastructure has been continuously expanded and today has a total length of 2.15 million km and a storage capacity of about 108.3 billion m³. The production of biomethane in the EU and its distribution by natural gas network offers an interesting alternative for the reconfiguration of EUs energy supply system. Up to now, biomethane is obtained by purifying and upgrading raw biogas in a complex process. In this study, a novel two-stage high pressure anaerobic digestion system was developed. This innovative concept aims to integrate biogas production, purification and pressure boosting within one system. The process is based on the enhanced water solubility of carbon dioxide compared to methane. By operating the methane reactor for biogas production at increased pressures, high amounts of dissolved carbon dioxide can be removed with the liquid effluent from the reactor, resulting in a high-calorific biogas. In batch experiments at pressures up to 30 bar, a significant influence of pressure on the pH-value in the reactor was observed, due to the augmented formation of carbon hydroxide. The study on the effect of a rapid pressure increase up to 100 bar showed no inhibition of the microorganisms in the batch-rigs too, although the microorganisms were not adapted to these environmental conditions. Furthermore, a continuously operated methane reactor was run at pressures up to 50 bar for the first time. The experiments showed that a stable anaerobic digestion process could be run at these pressures nearly without any problems and methane contents above 90% could be achieved. The promising results showed that this technology has great potential in producing on-site high calorific gas also in smaller units. In addition, the costs of post-production gas purification can be significantly reduced, due to the fact that the size of a subsequent gas purification unit can be decreased. Furthermore, the produced gas can be injected into the transnational gas grids without post pressurization or can be used in the transportation sector.In der EU hat die Nutzung von Erdgas zur Erzeugung von Strom und Wärme seit den 1990er Jahren zunehmend an Bedeutung gewonnen. Infolge dessen wurde die Erdgasinfrastruktur kontinuierlich ausgebaut und umfasst heute eine Leitungslänge von 2,15 Mio. km und ein Speichervolumen von 108,3 Mrd. m³. Eine interessante Alternative zur Neugestaltung des Energieversorgungssystems in der EU ist die Erzeugung von Biomethan und die anschließende Einspeisung in das bestehende Erdgasnetz. Biomethan wird bisher in einem aufwendigen Reinigungs- und Aufbereitungsverfahren aus Rohbiogas gewonnen. In der vorliegenden Studie wurde ein neuartiges zweistufiges Hochdruckfermentationsverfahren entwickelt. Ziel dieses innovativen Konzepts ist die Integration von Biogaserzeugung, -aufbereitung und -verdichtung in ein einziges Verfahren. Dieses Verfahren basiert auf der erhöhten Wasserlöslichkeit von Kohlenstoffdioxid im Vergleich zum Methan. Durch den Betrieb des Methanreaktors unter erhöhtem Druck können große Mengen an gelöstem Kohlenstoffdioxid mit dem Effluent aus dem Reaktor ausgetragen werden, was die Erzeugung eines hochkalorischen Biogases ermöglicht. Mithilfe von Batch Experimenten im Labormaßstab bei Betriebsdrücken bis 30 bar konnte ein signifikanter Einfluss des Drucks auf den pH-Wert im Reaktor ermittelt werden, aufgrund der ansteigenden Bildung von Hydrogencarbonat. Die schnelle Druckerhöhung in den Batch-Reaktoren in weiteren Untersuchungen bis zu 100 bar zeigte keinerlei Hemmung der Mikroorganismen, obwohl diese nicht an die neuen Umgebungsbedingungen angepasst waren. Außerdem wurde erstmalig ein kontinuierlicher Methanreaktor bei Drücken bis 50 bar betrieben. Dabei konnte gezeigt werden, dass ein kontinuierlicher Betrieb des Methanreaktors bei Drücken bis 50 bar nahezu problemlos möglich ist und Methangehalte von über 90% realisiert werden können. Diese vielversprechenden Ergebnisse zeigen, dass diese Technologie ein großes Potential für die Herstellung von hochkalorischem Gas auch in kleineren Maßstäben vor Ort bietet. Außerdem können die Kosten für eine nachgeschaltete Aufbereitungseinheit signifikant reduziert werden, da diese deutlich kleiner ausfallen könnte. Darüber hinaus kann das erzeugte Gas ohne weitere Verdichtung in das Erdgasnetz eingespeist oder im Transportsektor als Treibstoff eingesetzt werden

06051 Abstracts Collection -- Kolmogorov Complexity and Applications

From 29.01.06 to 03.02.06, the Dagstuhl Seminar 06051 ``Kolmogorov Complexity and Applications\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Znaczenie prognostyczne obrazowania metodą kardiologicznego rezonansu magnetycznego: uaktualnienie informacji na 2010 rok

Obrazowanie metodą kardiologicznego rezonansu magnetycznego (CMR) stało się niezbędną techniką w diagnostyce i leczeniu pacjentów z chorobami sercowo-naczyniowymi. Postępy techniczne sprawiły, że CMR jest wyjątkową metodą oceny budowy anatomicznej, fizjologii i patofizjologii układu sercowo-naczyniowego. Pozwala bowiem na uzyskanie obrazów tomograficznych ludzkiego serca i naczyń o wysokiej rozdzielczości w dowolnej płaszczyźnie. Ponadto, kontrast w obrazowaniu tkanek miękkich przewyższa inne konkurencyjne metody, bez konieczności stosowania promieniowania jonizującego. Obrazowanie CMR stanowi referencyjną metodę oceny funkcji lewej i prawej komory serca oraz wykrywania nieprawidłowości tkanki mięśnia sercowego, takich jak obrzęk, martwica czy blizna. Dla celów prognostycznych największe znaczenie w obrazowaniu CMR ma wykrycie nieprawidłowej budowy lub dysfunkcji serca, a także niedokrwienia i/lub blizny pozawałowej w obrębie mięśnia sercowego. W niniejszym artykule krótko opisano znaczenie prognostyczne obrazowania CMR z zastosowaniem kilku technik oraz scharakteryzowano obrazy obserwowane u pacjentów z chorobą wieńcową (CAD), kardiomiopatiami i przewlekłą niewydolnością serca. Niedokrwienie mięśnia sercowego okazało się silnym czynnikiem predykcyjnym niekorzystnych zdarzeń sercowo- -naczyniowych u pacjentów z CAD. Uszkodzenie mikrokrążenia u chorych z ostrym zawałem serca jest nowym, niezależnym czynnikiem zapowiadającym negatywną przebudowę lewej komory serca oraz pogarszającym rokowanie. Również obecność blizny oraz nierozpoznany zawał serca wiążą się z ryzykiem niekorzystnych zdarzeń sercowo-naczyniowych. Obecność włóknienia u pacjentów z kardiomiopatią rozstrzeniową czy przerostową stanowi silny czynnik ryzyka zagrażających życiu tachyarytmii komorowych i obciąża rokowanie. Obrazowanie CMR pozwala na dokładniejszą ocenę między- i śródkomorowej dyssynchronii skurczu i identyfikuje obszary włóknienia w mięśniu sercowym, które mają znaczenie prognostyczne. (Folia Cardiologica Excerpta 2011; 6, 1: 17–27

Operating performance of full-scale agricultural biogas plants in Germany and China : results of a year-round monitoring program

Germany (DE) and China (CN) have different political approaches in supporting the biogas sector. Three German and three Chinese large-scale biogas plants (BGPs) were evaluated as part of a year-round monitoring program. Laboratory methods were utilized to analyze the chemical indicators. Results showed a stable anaerobic digestion process without system failures in all BGPs. The methane yield had a range of 0.23–0.35 m3 CH4/kgODM for DE BGPs and 0.11–0.22 m3 CH4/kgODM for CN BGPs, due to different substrates and working temperatures. Financial analyses indicated that DE BGPs are viable under their current feed-in tariffs contracts. Their financial internal rate of return (IRR) ranged between 8 and 22%. However, all CN BGPs had negative IRRs, indicating that they are financially unfeasible. Risk analyses illustrated that DE BGPs will face financial nonviability if benefits decrease by 9–33% or costs increase by 10–49%, or if a combined worse case (benefit decrease and cost increase) of 5 20% occurs. Incentives to BGP operations are particularly important in China, where the government should consider switching the construction-based subsidy to a performancebased subsidy system to motivate the operators. BGP monitoring is necessary to understand the performance, in addition to briefing policymakers in case a policy reform is neede

Distinct Mammalian Precursors Are Committed to Generate Neurons with Defined Dendritic Projection Patterns

The mechanisms that regulate how dendrites target different neurons to establish connections with specific cell types remain largely unknown. In particular, the formation of cell-type–specific connectivity during postnatal neurogenesis could be either determined by the local environment of the mature neuronal circuit or by cell-autonomous properties of the immature neurons, already determined by their precursors. Using retroviral fate mapping, we studied the lamina-specific dendritic targeting of one neuronal type as defined by its morphology and intrinsic somatic electrical properties in neonatal and adult neurogenesis. Fate mapping revealed the existence of two separate populations of neuronal precursors that gave rise to the same neuronal type with two distinct patterns of dendritic targeting—innervating either a deep or superficial lamina, where they connect to different types of principal neurons. Furthermore, heterochronic and heterotopic transplantation demonstrated that these precursors were largely restricted to generate neurons with a predetermined pattern of dendritic targeting that was independent of the host environment. Our results demonstrate that, at least in the neonatal and adult mammalian brain, the pattern of dendritic targeting of a given neuron is a cell-autonomous property of their precursors