spl(2,1) dynamical supersymmetry and suppression of ferromagnetism in flat band double-exchange models

The low energy spectrum of the ferromagnetic Kondo lattice model on a N-site complete graph extended with on-site repulsion is obtained from the underlying spl(2,1) algebra properties in the strong coupling limit. The ferromagnetic ground state is realized for 1 and N+1 electrons only. We identify the large density of states to be responsible for the suppression of the ferromagnetic state and argue that a similar situation is encountered in the Kagome, pyrochlore, and other lattices with flat bands in their one-particle density of states.Comment: 7 pages, 1 figur

New modelling technique for aperiodic-sampling linear systems

A general input-output modelling technique for aperiodic-sampling linear systems has been developed. The procedure describes the dynamics of the system and includes the sequence of sampling periods among the variables to be handled. Some restrictive conditions on the sampling sequence are imposed in order to guarantee the validity of the model. The particularization to the periodic case represents an alternative to the classic methods of discretization of continuous systems without using the Z-transform. This kind of representation can be used largely for identification and control purposes.Comment: 19 pages, 0 figure

Detecting and diagnosing faults in dynamic stochastic distributions using a rational b-splines approximation to output PDFs

Describes the process of detecting and diagnosing faults in dynamic stochastic distributions using a rational b-splines approximation to output PDFs

Set optimization - a rather short introduction

Recent developments in set optimization are surveyed and extended including various set relations as well as fundamental constructions of a convex analysis for set- and vector-valued functions, and duality for set optimization problems. Extensive sections with bibliographical comments summarize the state of the art. Applications to vector optimization and financial risk measures are discussed along with algorithmic approaches to set optimization problems

Do long-term hospitalised patients benefit from discharge into the community?

The original publication is available at www.springerlink.co

Mycolactone-dependent depletion of endothelial cell thrombomodulin is strongly associated with fibrin deposition in Buruli ulcer lesions

A well-known histopathological feature of diseased skin in Buruli ulcer (BU) is coagulative necrosis caused by the Mycobacterium ulcerans macrolide exotoxin mycolactone. Since the underlying mechanism is not known, we have investigated the effect of mycolactone on endothelial cells, focussing on the expression of surface anticoagulant molecules involved in the protein C anticoagulant pathway. Congenital deficiencies in this natural anticoagulant pathway are known to induce thrombotic complications such as purpura fulimans and spontaneous necrosis. Mycolactone profoundly decreased thrombomodulin (TM) expression on the surface of human dermal microvascular endothelial cells (HDMVEC) at doses as low as 2ng/ml and as early as 8hrs after exposure. TM activates protein C by altering thrombin's substrate specificity, and exposure of HDMVEC to mycolactone for 24 hours resulted in an almost complete loss of the cells' ability to produce activated protein C. Loss of TM was shown to be due to a previously described mechanism involving mycolactone-dependent blockade of Sec61 translocation that results in proteasome-dependent degradation of newly synthesised ER-transiting proteins. Indeed, depletion from cells determined by live-cell imaging of cells stably expressing a recombinant TM-GFP fusion protein occurred at the known turnover rate. In order to determine the relevance of these findings to BU disease, immunohistochemistry of punch biopsies from 40 BU lesions (31 ulcers, nine plaques) was performed. TM abundance was profoundly reduced in the subcutis of 78% of biopsies. Furthermore, it was confirmed that fibrin deposition is a common feature of BU lesions, particularly in the necrotic areas. These findings indicate that there is decreased ability to control thrombin generation in BU skin. Mycolactone's effects on normal endothelial cell function, including its ability to activate the protein C anticoagulant pathway are strongly associated with this. Fibrin-driven tisischemia could contribute to the development of the tissue necrosis seen in BU lesions

Automotive Magneto-Rheological Dampers:Modelling and Parameter Identification using contrast-based Fruit Fly Optimisation

The present study discusses the mechanical behaviour and modelling of a prototype automotive magneto-rheological (MR) damper, which presents different viscous damping coefficients in jounce and rebound. The force generated by the MR damper is measured at different velocities and electrical currents, and a modified damper model is proposed to improve fitting of the experimental data. The model is calibrated by means of parameter identification and for this purpose a new swarm intelligence algorithm is proposed, that we call the contrast-based Fruit Fly Optimisation Algorithm (c-FOA). The performance of c-FOA is compared with that of Genetic Algorithms, Particle Swarm Optimisation, Differential Evolution and Artificial Bee Colony. The comparison is made on the basis of no a-priori knowledge of the damper model parameters range. The results confirm the good performance of c-FOA under parametric range uncertainty. A sensitivity analysis discusses c-FOA’s performance with respect to its tuning parameters. Finally, a ride comfort simulation study quantifies the discrepancies in the results, for different identified damper model sets. The discrepancies underline the importance of accurately describing MR damper nonlinear behaviour, considering that virtual sign-off processes are increasingly gaining momentum in the automotive industry.<br/

Invasive Rosa rugosa populations outperform native populations, but some populations have greater invasive potential than others

Increased performance of invasive plant species in their introduced range vs. their native range has been previously documented. However, performance differences among invasive populations have rarely been explored, despite this information being central to understanding the evolution of invasiveness as well as being a useful basis to inform management of invasive species. To examine variation in performance among populations of Rosa rugosa in its introduced range, and whether introduced populations perform better than native populations, we quantified growth and reproductive traits in five invasive populations in northwest Europe and two native and declining populations in China. Overall, we found that the introduced R. rugosa populations we sampled performed significantly better than the sampled native populations for growth and reproductive traits (2 to 4 fold increase). However, there was significant variation for most traits among the five invasive populations, demonstrating that some introduced populations we sampled were more successful invaders than others. Our findings provide a useful foundation for management of invasive R. rugosa in Europe, and support the recent call for more intra-species research in invasive species biology.Shuping Zhang, Maike Isermann, Wenhao Gan, Martin Bree

‘This restless enemy of all fertility’: exploring paradigms of coastal dune management in Western Europe over the last 700 years

Drifting sand has inundated settlements and damaged agricultural land along the coasts of Western Europe for the last 700 years. The need to control sand migration has been an important driver of the management of coastal sand dunes and here we analyse original archival materials to provide new insights into historically changing coastal dune management practices. Records of coastal sand movement in Denmark, The Netherlands, Britain, Ireland and France were reviewed and three distinct management approaches were identified. The ways in which these approaches have played out in space and time were examined with particular reference to records from landed estates in Britain and Ireland. We demonstrate how historical evidence can be used to inform contemporary debates on dune management strategy and practice. We propose a new place-based approach to the future management of coastal dunes that can incorporate both expert and locally produced ‘knowledges’ and that is underpinned by an understanding of how both natural forces and human interventions have shaped these dune landscapes over time