Time--Splitting Schemes and Measure Source Terms for a Quasilinear Relaxing System

Several singular limits are investigated in the context of a $2 \times 2$ system arising for instance in the modeling of chromatographic processes. In particular, we focus on the case where the relaxation term and a $L^2$ projection operator are concentrated on a discrete lattice by means of Dirac measures. This formulation allows to study more easily some time-splitting numerical schemes

Total arrest of spontaneous and evoked synaptic transmission but normal synaptogenesis in the absence of Munc13-mediated vesicle priming

Synaptic vesicles must be primed to fusion competence before they can fuse with the plasma membrane in response to increased intracellular Ca2+ levels. The presynaptic active zone protein Munc13-1 is essential for priming of glutamatergic synaptic vesicles in hippocampal neurons. However, a small subpopulation of synapses in any given glutamatergic nerve cell as well as all gamma-aminobutyratergic (GABAergic) synapses are largely independent of Munc13-1. We show here that Munc13-2, the only Muncl 3 isoform coexpressed with Munc13-1 in hippocampus, is responsible for vesicle priming in Munc13-1 independent hippocampal synapses. Neurons lacking both Munc13-1 and Munc13- 2 show neither evoked nor spontaneous release events, yet form normal numbers of synapses with typical ultrastructural features. Thus, the two Munc13 isoforms are completely redundant in GABAergic cells whereas glutamatergic neurons form two types of synapses, one of which is solely Munc13-1 dependent and lacks Munc13-2 whereas the other type employs Munc13-2 as priming factor. We conclude that Munc13-mediated vesicle priming is not a transmitter specific phenomenon but rather a general and essential feature of multiple fast neurotransmitter systems, and that synaptogenesis during development is not dependent on synaptic secretory activity

Two-Temperature Intracluster Medium in Merging Clusters of Galaxies

We investigate the evolution of intracluster medium during a cluster merger, explicitly considering the relaxation process between the ions and electrons by N-body and hydrodynamical simulations. When two subclusters collide each other, a bow shock is formed between the centers of two substructures and propagate in both directions along the collision axis. The shock primarily heats the ions because the kinetic energy of an ion entering the shock is larger than that of an electron by the ratio of masses. In the post-shock region the energy is transported from the ions to electrons via Coulomb coupling. However, since the energy exchange timescale depends both on the gas density and temperature, distribution of electron temperature becomes more complex than that of the plasma mean temperature, especially in the expanding phase. After the collision of two subclusters, gas outflow occurs not only along the collision axis but also in its perpendicular direction. The gas which is originally located in the central part of the subclusters moves both in the parallel and perpendicular directions. Since the equilibrium timescale of the gas along these directions is relatively short, temperature difference between ions and electrons is larger in the directions tilted by the angles of $\pm 45^\circ$ with respect to the collision axis. The electron temperature could be significantly lower that the plasma mean temperature by $\sim 50$ at most. The significance of our results in the interpretation of X-ray observations is briefly discussed.Comment: 20 pages, 11 figures, Accepted for publication in Ap

Decentralised Learning MACs for Collision-free Access in WLANs

By combining the features of CSMA and TDMA, fully decentralised WLAN MAC schemes have recently been proposed that converge to collision-free schedules. In this paper we describe a MAC with optimal long-run throughput that is almost decentralised. We then design two \changed{schemes} that are practically realisable, decentralised approximations of this optimal scheme and operate with different amounts of sensing information. We achieve this by (1) introducing learning algorithms that can substantially speed up convergence to collision free operation; (2) developing a decentralised schedule length adaptation scheme that provides long-run fair (uniform) access to the medium while maintaining collision-free access for arbitrary numbers of stations

The Origin of the Silicate Emission Features in the Seyfert 2 Galaxy, NGC 2110

The unified model of active galactic nuclei (AGN) predicts silicate emission features at 10 and 18 microns in type 1 AGN, and such features have now been observed in objects ranging from distant QSOs to nearby LINERs. More surprising, however, is the detection of silicate emission in a few type 2 AGN. By combining Gemini and Spitzer mid-infrared imaging and spectroscopy of NGC 2110, the closest known Seyfert 2 galaxy with silicate emission features, we can constrain the location of the silicate emitting region to within 32 pc of the nucleus. This is the strongest constraint yet on the size of the silicate emitting region in a Seyfert galaxy of any type. While this result is consistent with a narrow line region origin for the emission, comparison with clumpy torus models demonstrates that emission from an edge-on torus can also explain the silicate emission features and 2-20 micron spectral energy distribution of this object. In many of the best-fitting models the torus has only a small number of clouds along the line of sight, and does not extend far above the equatorial plane. Extended silicate-emitting regions may well be present in AGN, but this work establishes that emission from the torus itself is also a viable option for the origin of silicate emission features in active galaxies of both type 1 and type 2.Comment: ApJL, accepte

Strategy for Designing DSM Program after the Restructuring in Korea

To maintain supply adequacy and mitigate price volatility in electricity market, the necessity for obtaining demandside resource is increasing and obtaining demand-side resource is set as a priority of electricity policy. For this purpose, we introduce a new DSM mechanism and program development strategies based on customer response and electricity industry efficiency. Especially we introduced DLC(Direct Load Control) technology via two-way communication scheme for large customer. This DLC program targets interruptible load that covers large customer in commercial and industrial sector. This program can retain demand reserve that does not interrupt process in plant or business along with real-time monitoring load condition of end-use and interrupt load by pre-determined procedures, if necessary. This analysis shows that electricity boiler, pump, blower, HVAC can save energy during some time. In addition, developing system to monitor end-use load and interconnecting it with MOS(Market Operation System) should be established as infrastructure in DSM

Multiform antimicrobial resistance from a metabolic mutation

A critical challenge for microbiology and medicine is how to cure infections by bacteria that survive antibiotic treatment by persistence or tolerance. Seeking mechanisms behind such high survival, we developed a forward-genetic method for efficient isolation of high24 survival mutants in any culturable bacterial species. We found that perturbation of an essential biosynthetic pathway (arginine biosynthesis) in a mycobacterium generated three distinct forms of resistance to diverse antibiotics, each mediated by induction of WhiB7— high persistence and tolerance to kanamycin, high survival upon exposure to rifampicin, and MIC-shifted resistance to clarithromycin. As little as one base change in a gene encoding a metabolic pathway component conferred multiple forms of resistance to multiple antibiotics with different targets. This extraordinary resilience may help explain how sub31 sterilizing exposure to one antibiotic in a regimen can induce resistance to others and invites development of drugs targeting the mediator of multiform resistance, WhiB7

Magnetic Pulse Welding of the “Tube – Plug” Pair of STS410 Steel

The research was focused on the magnetic pulse welding (MPW) of 12.5% Cr steel STS410. The experiments were performed in the tube-plug geometry (both details were made of the same steel). Magnetic pulse unit consisted of pulsed current generator (PCG) loaded to a single-turn coil. Magnetic field amplitude of 40 T was generated in the coil during experiments. The amplitude of pulsed current reached 750 kA. The effects of energy storage capacity, charging voltage, and end plug shape were studied. The welded samples were investigated by optical microscopy. The optimal velocities of impact and contact front motion were evaluated as 300 m/s and 3-3.5 km/s, respectively. The paper includes the leakage test results as well. To date, the joints with a helium leak rate of 10-9 mbar·l·s-1 have been produced

Arts on prescription for community‐dwelling older people with a range of health and wellness needs

Published evidence for the role of participatory art in supporting health and well‐being is growing. The Arts on Prescription model is one vehicle by which participatory art can be delivered. Much of the focus of Arts on Prescription has been on the provision of creative activities for people with mental health needs. This Arts on Prescription program, however, targeted community‐dwelling older people with a wide range of health and wellness needs. Older people were referred to the program by their healthcare practitioner. Professional artists led courses in visual arts, photography, dance and movement, drama, singing, or music. Classes were held weekly for 8–10 weeks, with six to eight participants per class, and culminated with a showing of work or a performance. Program evaluation involved pre‐ and postcourse questionnaires, and focus groups and individual interviews. Evaluation data on 127 participants aged 65 years and older were available for analysis. We found that Arts on Prescription had a positive impact on participants. Quantitative findings revealed a statistically significant improvement in the Warwick–Edinburgh Mental Well‐being Scale(WEMWBS) as well as a statistically significant increase in the level of self‐reported creativity and frequency of creative activities. Qualitative findings indicated that the program provided challenging artistic activities which created a sense of purpose and direction, enabled personal growth and achievement, and empowered participants, in a setting which fostered the development of meaningful relationships with others. This evaluation adds to the evidence base in support of Arts on Prescription by expanding the application of the model to older people with a diverse range of health and wellness needs