Chromospheric oscillations

We show results from SO/Sacramento Peak data to discuss three issues: (i)--the spatial occurrence of chromospheric 3--min oscillations; (ii)--the validity of Ca II H&K line-center Doppler Shift measurements; (iii)--the signi ?cance of oscillation power and phase at frequencies above 10 mHz

Optimized magneto-optical isolator designs inspired by seedlayer-free terbium iron garnets with opposite chirality

Simulations demonstrate that undoped yttrium iron garnet (YIG) seedlayers cause reduced Faraday rotation in silicon-on-insulator (SOI) waveguides with Ce-doped YIG claddings. Undoped seedlayers are required for the crystallization of the magneto-optical Ce:YIG claddings, but they diminish the interaction of the Ce:YIG with the guided modes. Therefore new magneto-optical garnets, terbium iron garnet (TIG) and bismuth-doped TIG (Bi:TIG), are introduced that can be integrated directly on Si and quartz substrates without seedlayers. The Faraday rotations of TIG and Bi:TIG films at 1550nm were measured to be +500 and -500°/cm, respectively. Simulations show that these new garnets have the potential to significantly mitigate the negative impact of the seedlayers under Ce:YIG claddings. The successful growth of TIG and Bi:TIG on low-index fused quartz inspired novel garnet-core waveguide isolator designs, simulated using finite difference time domain (FDTD) methods. These designs use alternating segments of positive and negative Faraday rotation for push-pull quasi phase matching in order to overcome birefringence in waveguides with rectangular cross-sections

Correcting for Distortions due to Ionization in the STAR TPC

Physics goals of the STAR Experiment at RHIC in recent (and future) years drive the need to operate the STAR TPC at ever higher luminosities, leading to increased ionization levels in the TPC gas. The resulting ionic space charge introduces field distortions in the detector which impact tracking performance. Further complications arise from ionic charge leakage into the main TPC volume from the high gain anode region. STAR has implemented corrections for these distortions based on measures of luminosity, which we present here. Additionally, we highlight a novel approach to applying the corrections on an event-by-event basis applicable in conditions of rapidly varying ionization sources.Comment: 6 pages, 7 figures, proceedings of the Workshop on Tracking in High Multiplicity Environments (TIME 05) in Zurich, Switzerland, submitted to Nucl. Instr. and Meth.

Sedimentology and depositional environments in the Mesozoic, West of Shetland

As part of Phase 3 of the Faroe-Shetland Consortium project on the UK sector of the Faroe-Shetland Basin, BGS completed detailed (10 cm-scale) sedimentary logging of 604.77 m of conventional core recovered from 19 wells, drilled between 1974 and 1995. The project originally focussed solely on Jurassic-aged sediments, as identified in BGS held well databases. In reality, the project examined a suit of sediments ranging from the Triassic, Jurassic and Lower Cretaceous. In addition, a suite of complementary palynological sampling was completed. The goal was to provide additional depositional environment information from palyno-facies analysis, along with age determination for the sediments. Together, the two new datasets form an integrated re-assessment of the Mesozoic-aged depositional environments located to the West of Shetland. The Triassic-aged deposits of the Papa Group record deposition in a fluvial environment, whereby the fluvial systems display meandering to braided characteristics. In places, particularly in the upper parts of the cored Triassic-aged strata, the sediments display evidence for nearshore, wave-working processes. The nearshore working may be evidence for a transgression event at the top of the cored Triassic interval; something which should be investigated further in the future. Within the Jurassic-aged succession, two main groups were analysed: the Skerry Group and the Humber Group. Sediments within the Skerry Group were deposited within a fully marine, shelfal environment (the Stack Skerry Formation) and a relatively deeper-water, outer shelf to bathyal environment (the Sule Skerry Formation). Late Jurassic-aged sediments from the Humber Group are represented by the Rona Member, the Solan Sandstone Member and the Ridge Conglomerate Member. BGS has subdivided the Rona Member into five “facies”, largely on the basis of depositional environment. These include: Rona R1 (Fluvial), Rona R2 (Fan Delta), Rona R3 (Marginal Marine), Rona R4 (Shoreface/Littoral) and Rona R5 (Shallow Marine). Deposits of the Rona R4 facies represent good hydrocarbon reservoir targets, whilst the Rona R3 facies has the potential to form a sourcing lithology. The Solan Sandstone Member, interpreted to be contemporaneous with the deposition of the Rona Member, was deposited in a deep-marine, turbidite fan system. The Kimmeridge Clay Formation is encountered in a number of wells, typically represented by a dark grey- to black-coloured, hemi-pelagic mud-prone succession. The Early Cretaceous-aged Cromer Knoll Group is also present in the core data, represented by: turbidite fan deposits, formed in a deep marine environment (204/19-1 & 205/21-1A); and by shoreface/littoral deposits representative of a marine setting (205/26a-2). These sediments appear to rest unconformably on the Kimmeridge Clay Formation

In-line characterisation of continuous phase conductivity in slurry flows using artificial intelligence tomography

Electrical Impedance Tomography (EIT) can be applied to monitor a variety of mineral and chemical processes including: velocity measurements in drilling cuttings and hydrocyclone operations. Hydraulic conveying systems rely upon the knowledge of slurry density to ensure efficient transportation of the solids. Typically, density measurements exploit the attenuation of gamma ray photons which poses complex safety, operational and regulatory concerns with Electrical Impedance Tomography affording a non-nuclear alternative to traditional approaches. To optimise the accuracy of this non-nuclear density measurement, the electrical conductivity of the aqueous phase in a multi-component slurry, is required. Whilst conductivity probes are sufficiently accurate, there are often drawbacks and limitations due to installation restrictions, as it is difficult to separate aqueous and solid phases in real-time. Electrical Impedance Fingerprinting (EIF), is a novel measurement technique which characterises formulation properties, in-situ, based upon electrical impedance sensing and artificial intelligence algorithms. This paper outlines the development of EIF and its application to monitor aqueous phase conductivity in multi-component slurries, containing sands and clays. EIF accurately predicts this conductivity with high accuracy and a root-mean squared error of 0.055 mS cm−1. This development ensures accurate non-nuclear density measurements (<5%) are obtained across an extended aqueous electrical conductivity range of 1.5–70 mS cm−1. This encompasses the majority of target hydraulic conveying systems in mining operations. EIF also enhances the functionality of ‘traditional’ electrical tomography as not only are mineral processes able to be visualised, but the process materials are simultaneously characterised, to improve process understanding, optimisation and control

European Quality in Preclinical Data (EQIPD):Een breed consortium voor het verbeteren van de kwaliteit van proefdieronderzoek

Het merendeel van de dierstudies, zowel in de industrie als in de academische wereld, wordt uitgevoerd ten behoeve van de menselijke gezondheid: we gebruiken ze als voorspeller voor effecten in mensen, bijvoorbeeld bij de ontwikkeling van nieuwe geneesmiddelen of medische interventies, in de toxicologie, en ook in fundamenteel onderzoek

Actors that Unify Threads and Events

There is an impedance mismatch between message-passing concurrency and virtual machines, such as the JVM. VMs usually map their threads to heavyweight OS processes. Without a lightweight process abstraction, users are often forced to write parts of concurrent applications in an event-driven style which obscures control flow, and increases the burden on the programmer. In this paper we show how thread-based and event-based programming can be unified under a single actor abstraction. Using advanced abstraction mechanisms of the Scala programming language, we implemented our approach on unmodified JVMs. Our programming model integrates well with the threading model of the underlying VM

Minimal Steiner Trees for 2k×2kSquare Lattices

AbstractWe prove a conjecture of Chung, Graham, and Gardner (Math. Mag.62(1989), 83–96), giving the form of the minimal Steiner trees for the set of points comprising the vertices of a 2k×2ksquare lattice. Each full component of these minimal trees is the minimal Steiner tree for the four vertices of a square