8,329 research outputs found
Test, Control and Monitor System (TCMS) operations plan
The purpose is to provide a clear understanding of the Test, Control and Monitor System (TCMS) operating environment and to describe the method of operations for TCMS. TCMS is a complex and sophisticated checkout system focused on support of the Space Station Freedom Program (SSFP) and related activities. An understanding of the TCMS operating environment is provided and operational responsibilities are defined. NASA and the Payload Ground Operations Contractor (PGOC) will use it as a guide to manage the operation of the TCMS computer systems and associated networks and workstations. All TCMS operational functions are examined. Other plans and detailed operating procedures relating to an individual operational function are referenced within this plan. This plan augments existing Technical Support Management Directives (TSMD's), Standard Practices, and other management documentation which will be followed where applicable
Observationally-Motivated Analysis of Simulated Galaxies
The spatial and temporal relationships between stellar age, kinematics, and
chemistry are a fundamental tool for uncovering the physics driving galaxy
formation and evolution. Observationally, these trends are derived using
carefully selected samples isolated via the application of appropriate
magnitude, colour, and gravity selection functions of individual stars;
conversely, the analysis of chemodynamical simulations of galaxies has
traditionally been restricted to the age, metallicity, and kinematics of
`composite' stellar particles comprised of open cluster-mass simple stellar
populations. As we enter the Gaia era, it is crucial that this approach
changes, with simulations confronting data in a manner which better mimics the
methodology employed by observers. Here, we use the \textsc{SynCMD} synthetic
stellar populations tool to analyse the metallicity distribution function of a
Milky Way-like simulated galaxy, employing an apparent magnitude plus gravity
selection function similar to that employed by the RAdial Velocity Experiment
(RAVE); we compare such an observationally-motivated approach with that
traditionally adopted - i.e., spatial cuts alone - in order to illustrate the
point that how one analyses a simulation can be, in some cases, just as
important as the underlying sub-grid physics employed.Comment: Accepted for publication in PoS (Proceedings of Science): Nuclei in
the Cosmos XIII (Debrecen, Jul 2014); 6 pages; 3 figure
Galactic Archaeology and Minimum Spanning Trees
Chemical tagging of stellar debris from disrupted open clusters and
associations underpins the science cases for next-generation multi-object
spectroscopic surveys. As part of the Galactic Archaeology project TraCD
(Tracking Cluster Debris), a preliminary attempt at reconstructing the birth
clouds of now phase-mixed thin disk debris is undertaken using a parametric
minimum spanning tree (MST) approach. Empirically-motivated chemical abundance
pattern uncertainties (for a 10-dimensional chemistry-space) are applied to
NBODY6-realised stellar associations dissolved into a background sea of field
stars, all evolving in a Milky Way potential. We demonstrate that significant
population reconstruction degeneracies appear when the abundance uncertainties
approach 0.1 dex and the parameterised MST approach is employed; more
sophisticated methodologies will be required to ameliorate these degeneracies.Comment: To appear in "Multi-Object Spectroscopy in the Next Decade: Big
Questions, Large Surveys and Wide Fields"; Held: Santa Cruz de La Palma,
Canary Islands, Spain, 2-6 Mar 2015; ed. I Skillen & S. Trager; ASP
Conference Series (Figures now optimised for B&W printing
Direct optical excitation of a fullerene-incarcerated metal ion
The endohedral fullerene Er3N@C80 shows characteristic 1.5 micron
photoluminescence at cryogenic temperatures associated with radiative
relaxation from the crystal-field split Er3+ 4I13/2 manifold to the 4I15/2
manifold. Previous observations of this luminescence were carried out by
photoexcitation of the fullerene cage states leading to relaxation via the
ionic states. We present direct non-cage-mediated optical interaction with the
erbium ion. We have used this interaction to complete a
photoluminescence-excitation map of the Er3+ 4I13/2 manifold. This ability to
interact directly with the states of an incarcerated ion suggests the
possibility of coherently manipulating fullerene qubit states with light
Strengthening Sanctions: Solutions to Curtail the Evasion of International Economic Sanctions Through the Use of Cryptocurrency
Despite the ubiquity of cryptocurrency, no international uniform regulatory system exists. State-by-state regulation of cryptocurrencies has problematic implications for cross-border investigations and predictability in application. Moreover, this regulatory framework leaves open opportunities for actors worldwide to violate international sanctions with impunity.
This Note posits that an international regulatory framework is necessary to combat the evasion of financial sanctions on practical and theoretical grounds. It further argues that the best way to structure this new framework is through the enactment of a new multilateral treaty. A formal international regulatory mechanism for cryptocurrencies would have numerous benefits, foremost among them limiting the evasion of international sanctions. An international regulatory mechanism would also promote predictability in the regulation of cryptocurrencies. This would in turn entice institutional investors to build out the field of crypto users and encourage stability in an otherwise volatile marketplace.
The proposal outlined within this Note goes beyond standard legal justifications for a multilateral mechanism. It drills down into the substantive mechanisms that an effective treaty must include, such as public key cryptography; an international public key directory; prosecution guidelines; and foreign fine credits. The levels of specificity to this end are perhaps uncommon in a typical legal proposal. However, this analysis is essential to explain why a new, multilateral treaty is required. The current structures in place cannot begin to grapple with the complex underlying issues which are so crucial to the regulation of cryptocurrency. The substantive components of the proposed treaty undergird the very reason why a new multilateral treaty is necessary
On characteristic equations, trace identities and Casimir operators of simple Lie algebras
Two approaches are developed to exploit, for simple complex or compact real
Lie algebras g, the information that stems from the characteristic equations of
representation matrices and Casimir operators. These approaches are selected so
as to be viable not only for `small' Lie algebras and suitable for treatment by
computer algebra. A very large body of new results emerges in the forms, a) of
identities of a tensorial nature, involving structure constants etc. of g, b)
of trace identities for powers of matrices of the adjoint and defining
representations of g, c) of expressions of non-primitive Casimir operators of g
in terms of primitive ones. The methods are sufficiently tractable to allow not
only explicit proof by hand of the non-primitive nature of the quartic Casimir
of g2, f4, e6, but also e.g. of that of the tenth order Casimir of f4.Comment: 39 pages, 8 tables, late
Direct measurement of penetration length in ultra-thin and/or mesoscopic superconducting structures
We describe a method for direct measurement of the magnetic penetration
length in thin (10 - 100 nm) superconducting structures having overall
dimensions in the range 1 to 100 micrometers. The method is applicable for
broadband magnetic fields from dc to MHz frequencies.Comment: Accepted by Journal of Applied P:hysics (Jun 2006).5 pages, 5 figure
A randomised, controlled, double blind, non-inferiority trial of ultrasound-guided fascia iliaca block vs. spinal morphine for analgesia after primary hip arthroplasty
We performed a single centre, double blind, randomised, controlled, non-inferiority study comparing ultrasound-guided fascia iliaca block with spinal morphine for the primary outcome of 24-h postoperative morphine consumption in patients undergoing primary total hip arthroplasty under spinal anaesthesia with levobupivacaine. One hundred and eight patients were randomly allocated to receive either ultrasound-guided fascia iliaca block with 2 mg.kgâ1 levobupivacaine (fascia iliaca group) or spinal morphine 100 ÎŒg plus a sham ultrasound-guided fascia iliaca block using saline (spinal morphine group). The pre-defined non-inferiority margin was a median difference between the groups of 10 mg in cumulative intravenous morphine use in the first 24 h postoperatively. Patients in the fascia iliaca group received 25 mg more intravenous morphine than patients in the spinal morphine group (95% CI 9.0â30.5 mg, p < 0.001). Ultrasound-guided fascia iliaca block was significantly worse than spinal morphine in the provision of analgesia in the first 24 h after total hip arthroplasty. No increase in side-effects was noted in the spinal morphine group but the study was not powered to investigate all secondary outcomes
Field analysis of groundwater for volatile organic contaminants using on-column aqueous injection capillary gas chromatography
Northeast Utilities Service Company, Southern California Edison Company, Empire State Electric Energy Research Corporation, American Power Service Company, Standard Oil Company and New England Power Service Company under the MIT Energy Laboratory Utilites Progra
Subduction Duration and Slab Dip
The dip angles of slabs are among the clearest characteristics of subduction zones, but the factors that control them remain obscure. Here, slab dip angles and subduction parameters, including subduction duration, the nature of the overriding plate, slab age, and convergence rate, are determined for 153 transects along subduction zones for the present day. We present a comprehensive tabulation of subduction duration based on isotopic ages of arc initiation and stratigraphic, structural, plate tectonic and seismic indicators of subduction initiation. We present two ages for subduction zones, a longâterm age and a reinitiation age. Using cross correlation and multivariate regression, we find that (1) subduction duration is the primary parameter controlling slab dips with slabs tending to have shallower dips at subduction zones that have been in existence longer; (2) the longâterm age of subduction duration better explains variation of shallow dip than reinitiation age; (3) overriding plate nature could influence shallow dip angle, where slabs below continents tend to have shallower dips; (4) slab age contributes to slab dip, with younger slabs having steeper shallow dips; and (5) the relations between slab dip and subduction parameters are depth dependent, where the ability of subduction duration and overriding plate nature to explain observed variation decreases with depth. The analysis emphasizes the importance of subduction history and the longâterm regional state of a subduction zone in determining slab dip and is consistent with mechanical models of subduction
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