On the concept of pressure in quantum mechanics

Heat and work are fundamental concepts for thermodynamical systems. When these are scaled down to the quantum level they require appropriate embeddings. Here we show that the dependence of the particle spectrum on system size giving rise to a formal definition of pressure can, indeed, be correlated with an external mechanical degree of freedom, modelled as a spatial coordinate of a quantum oscillator. Under specific conditions this correlation is reminiscent of that occurring in the classical manometer.Comment: 7 pages, 3 figure

Relaxation into equilibrium under pure Schr\"odinger dynamics

We consider bipartite quantum systems that are described completely by a state vector $|\Psi(t)>$ and the fully deterministic Schr\"odinger equation. Under weak constraints and without any artificially introduced decoherence or irreversibility, the smaller of the two subsystems shows thermodynamic behaviour like relaxation into an equilibrium, maximization of entropy and the emergence of the Boltzmann energy distribution. This generic behaviour results from entanglement.Comment: 5 pages, 9 figure

Predictions from a stochastic polymer model for the MinDE dynamics in E.coli

The spatiotemporal oscillations of the Min proteins in the bacterium Escherichia coli play an important role in cell division. A number of different models have been proposed to explain the dynamics from the underlying biochemistry. Here, we extend a previously described discrete polymer model from a deterministic to a stochastic formulation. We express the stochastic evolution of the oscillatory system as a map from the probability distribution of maximum polymer length in one period of the oscillation to the probability distribution of maximum polymer length half a period later and solve for the fixed point of the map with a combined analytical and numerical technique. This solution gives a theoretical prediction of the distributions of both lengths of the polar MinD zones and periods of oscillations -- both of which are experimentally measurable. The model provides an interesting example of a stochastic hybrid system that is, in some limits, analytically tractable.Comment: 16 page

Localisation of the human hSuv3p helicase in the mitochondrial matrix and its preferential unwinding of dsDNA

We characterised the human hSuv3p protein belonging to the family of NTPases/helicases. In yeast mitochondria the hSUV3 orthologue is a component of the degradosome complex and participates in mtRNA turnover and processing, while in Caenorhabditis elegans the hSUV3 orthologue is necessary for viability of early embryos. Using immunofluorescence analysis, an in vitro mitochondrial uptake assay and sub‐fractionation of human mitochondria we show hSuv3p to be a soluble protein localised in the mitochondrial matrix. We expressed and purified recombinant hSuv3p protein from a bacterial expression system. The purified enzyme was capable of hydrolysing ATP with a Km of 41.9 µM and the activity was only modestly stimulated by polynucleotides. hSuv3p unwound partly hybridised dsRNA and dsDNA structures with a very strong preference for the latter. The presented analysis of the hSuv3p NTPase/helicase suggests that new functions of the protein have been acquired in the course of evolution

Teaching Index Numbers to economists

Economic statistics are frequently reported in the form of index numbers. This article considers how the field of Index Numbers should be approached in the teaching of a general economic degree. While the topic finds a natural home in statistics modules, it is emphasised that the area can also be referred to in the teaching of other areas of economics. It is also emphasised that the differences between Index Numbers theory and the practice of compiling economic statistics such as inflation can help students gain a better understanding of applied economic statistics. Methods for assessing learning in the area are also considered and available material to support teaching is also summarised

Current Results of the EC-sponsored Catchment Modelling (CatchMod) Cluster

To support the Water Framework Directive implementation, much research has been commissioned at both national and European levels. CatchMod is a cluster of these projects, which is focusing on the development of computational catchment models and related tools. This paper presents an overview of the results of the CatchMod cluster to dat

Nuclear Cryogenic Propulsion Stage

The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced NEP