Development of a dissolved CO2 sensor in true single-use format

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Eulertigs: Minimum Plain Text Representation of k-mer Sets Without Repetitions in Linear Time

Peer reviewe

Adiabatic quantum simulations with driven superconducting qubits

We propose a quantum simulator based on driven superconducting qubits where the interactions are generated parametrically by a polychromatic magnetic flux modulation of a tunable bus element. Using a time-dependent Schrieffer-Wolff transformation, we analytically derive a multi-qubit Hamiltonian which features independently tunable $XX$ and $YY$-type interactions as well as local bias fields over a large parameter range. We demonstrate the adiabatic simulation of the ground state of a hydrogen molecule using two superconducting qubits and one tunable bus element. The time required to reach chemical accuracy lies in the few microsecond range and therefore could be implemented on currently available superconducting circuits. Further applications of this technique may also be found in the simulation of interacting spin systems.Comment: 11 pages, 6 figure

Safety in s-t Paths, Trails and Walks

Given a directed graph G and a pair of nodes s and t, an s-t bridge of G is an edge whose removal breaks all s-t paths of G (and thus appears in all s-t paths). Computing all s-t bridges of G is a basic graph problem, solvable in linear time. In this paper, we consider a natural generalisation of this problem, with the notion of “safety” from bioinformatics. We say that a walk W is safe with respect to a set W' of s-t walks, if W is a subwalk of all walks in W'. We start by considering the maximal safe walks when consists of: all s-t paths, all s-t trails, or all s-t walks of G. We show that the solutions for the first two problems immediately follow from finding all s-t bridges after incorporating simple characterisations. However, solving the third problem requires non-trivial techniques for incorporating its characterisation. In particular, we show that there exists a compact representation computable in linear time, that allows outputting all maximal safe walks in time linear in their length. Our solutions also directly extend to multigraphs, except for the second problem, which requires a more involved approach. We further generalise these problems, by assuming that safety is defined only with respect to a subset of visible edges. Here we prove a dichotomy between the s-t paths and s-t trails cases, and the s-t walks case: the former two are NP-hard, while the latter is solvable with the same complexity as when all edges are visible. We also show that the same complexity results hold for the analogous generalisations of s-t articulation points (nodes appearing in all s-t paths). We thus obtain the best possible results for natural “safety”-generalisations of these two fundamental graph problems. Moreover, our algorithms are simple and do not employ any complex data structures, making them ideal for use in practice.Peer reviewe

What is the speed limit of martensitic transformations?

Structural martensitic transformations enable various applications, which range from high stroke actuation and sensing to energy efficient magnetocaloric refrigeration and thermomagnetic energy harvesting. All these emerging applications benefit from a fast transformation, but up to now their speed limit has not been explored. Here, we demonstrate that a thermoelastic martensite to austenite transformation can be completed within 10 ns. We heat epitaxial Ni-Mn-Ga films with a nanosecond laser pulse and use synchrotron diffraction to probe the influence of initial temperature and overheating on transformation rate and ratio. We demonstrate that an increase in thermal energy drives this transformation faster. Though the observed speed limit of 2.5 × 1027 (Js)1 per unit cell leaves plenty of room for further acceleration of applications, our analysis reveals that the practical limit will be the energy required for switching. Thus, martensitic transformations obey similar speed limits as in microelectronics, as expressed by the Margolus–Levitin theorem

Krankenhaus Rating Report 2011- Die fetten Jahre sind vorbei - Executive Summary

Im Jahr 2009 befanden sich 12% der Krankenhäuser im „roten Bereich“ mit erhöhter Insolvenzgefahr, 75% lagen im grünen Bereich, die restlichen 13% dazwischen. Die durchschnittliche Ausfallwahrscheinlichkeit betrug 2009 1,2%. Die wirtschaftliche Lage hat sich damit 2009 gegenüber 2008, als 14% der Krankenhäuser im roten und nur 69% im grünen Bereich waren, verbessert. Grundlage für diese Analysen ist eine Stichprobe von 687 Jahresabschlüssen aus 2008, die insgesamt 1 035 Krankenhäuser umfassen, und 366 aus 2009. 2009 erhöhten sich die KHG-Fördermittel erstmals seit 1995 spürbar um 6,5% auf 2,85 Mrd. €. Damit dürfte aber der langfristige Rückgang der Mittel nicht durchbrochen sein. Vielmehr dürfte es sich um eine antizyklische Stabilisierungsmaßnahme als Folge der Finanzkrise gehandelt haben. Legt man einen als notwendig erachteten jährlichen Investitionsbedarf von 10% des Krankenhausumsatzes zugrunde, beläuft sich die seit 1991 kumulierte Investitionslücke auf 30 Mrd. €. Allerdings füllen die Krankenhäuser einen wachsenden Teil dieser Lücke durch Investitionen aus Eigenmitteln, sodass der tatsächliche Investitionsstau nun 14 Mrd. € betragen dürfte. Die sinkende Fördermittelquote bestätigt sich auch in den Krankenhausbilanzen.[...]Krankenhäuser; Ausfallwahrscheinlichkeit; KHG-Fördermittel; Investitionslücke