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Sample records for mit gem basierter

  1. GEMS

    NASA Technical Reports Server (NTRS)

    Swank, Jean

    2009-01-01

    The prime scientific objectives of the Gravity and Extreme Magnetism SMEX, GEMS, are to determine the effects of the spin of black holes, the configurations of the magnetic fields of magnetars, and the structure of the supernova shocks which accelerate cosmic rays. In the cases of both stellar black holes and supermassive black holes, sensitivity to 1% polarization is needed to make diagnostic measurements of the net polarizations predicted for probable disk and corona models. GEMS can reach this goal for several Seyferts and quasars and measure the polarizations of representatives of a variety of other classes of X-ray sources, such as rotation-powered and accretion-powered pulsars. GEMS uses foil mirrors to maximize the collecting area achievable within the SMEX constraints. The polarimeters at the mirror foci are Time Projection Chambers which use the photoelectic effect to measure the polarization of the incident photon. We have built laboratory models with good efficiency and modulation in the 2-10 keV range. An attached small student experiment would add 0.5 keV sensitivity for bright soft sources. The instrument has a point spread function which allows measurement of structures in the brighter nearby supernova remnants. GEMS' Orbital Sciences spacecraft will rotate at a rate of 0.1 revolutions per minute during observations, so that systematic errors due to the detector can be detected and corrected. A program of 35 sources can be observed in 9 months. GEMS is designed for a two year lifetime which will allow a General Observer program that would more than double the number of sources measured. For subsets of black holes, neutron stars and supernova remnants, GEMS will measure the polarization of several sources, solving important questions while establishing the sensitivity required for future missions.

  2. DT Gem - ein RRab-Stern mit leichtem Blazhko-Effekt

    NASA Astrophysics Data System (ADS)

    Maintz, Gisela

    2016-01-01

    CCD observations of the RRab star DT Gem (RA = 06 06 58.09, DE = +25 24 02.0 (2000)) were obtained at my private observatory. For DT Gem 8 maxima were obtained. The amplitude of the light-curve varies epoch to epoch. So does the stepness of the rising and descending branch also. These variations are due to a small Blazhko effect. The observations will be continued to find the Blazhko period. Elements of DT Gem are revised as: DT Gem: Max = 2456355.4134 + 0.611283 * E, which is shorter than given in GCVS. Phased lightcurves of DT Gem provided by IOMC, SuperWASP, ASAS and NSVS are given.

  3. Gem Analysis

    NASA Technical Reports Server (NTRS)

    1981-01-01

    World Gem Laboratory, Inc.'s cathodoluminoscope is an instrument that magnifies a specimen and produces heat-generated light emissions that bring out features important in gemological analysis. It can indicate whether a stone can be successfully cut, useful in the study of growth and strain patterns in diamonds, detection of dyes in jade, and analysis of the growth and structure of rubies and sapphires. In combination with other tests these analyses can separate synthetic from natural gems.

  4. Mechanism of GEMS formation

    SciTech Connect

    Bradley, J P; Dai, Z R

    2004-03-10

    GEMS (glass with embedded metal and sulfides) in interplanetary dust particles (IDPs) were examined using 200 keV analytical transmission electron microscopy. The morphologies and crystallography of embedded relict grains reveal that GEMS are pseudomorphs formed by irradiation processing of crystals free-floating in space. Some GEMS retain a compositional and morphological ''memory'' of the crystal from which they formed. Pseudomorphism rules out condensation, annealing, flash heating, or shock melting as alternative mechanisms of GEMS formation. A significant and often dominant fraction of the atoms in GEMS were sputtered deposited from other grains. Therefore, a normal (solar) isotopic composition is not a reliable indicator of whether GEMS formed in the solar system or in presolar interstellar or circumstellar environments.

  5. Not Your Ordinary GEM

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Through Small Business Innovation Research (SBIR) funding from NASA's Stennis Space Center, Geophex devised a new design for broadband electromagnetic sensors. Geophex developed a patented sensing technology, capable not only of coastal monitoring, but also a variety of other functions, including environmental pollution characterization, groundwater contamination detection, archaeological study, and mineral detection. The new technology is offered in several of the company's products the GEM-2, GEM-2A, and the GEM-3. The Geophex products consist of two primary electromagnetic coils, which are stimulated by alternating currents that generate a magnetic field in the object targeted for investigation. GEM-2 is a handheld, lightweight, programmable, digital device. GEM-2A is an airborne version of the sensor. Suspended from a helicopter, the GEM-2A is used to search for mineral deposits and to survey large tracts of land. The GEM-3 is capable of detecting buried landmines and other active munitions. GEM-3 identifies landmines by their brand names. Because each landmine has its own unique electromagnetic response to the broad frequency band emitted by the GEM-3, bomb identification and disposal strategies are made easier.

  6. GEM: Performance and aging tests

    SciTech Connect

    Cho, H.S.; Kadyk, J.; Han, S.H.; Hong, W.S.; Perez-Mendez, V.; Wenzel, W.; Pitts, K.; Martin, M.D.; Hutchins, J.B.

    1999-06-01

    Performance and aging tests have been done to characterize Gas Electron Multipliers (GEMs), including further design improvements such as a thicker GEM and a closed GEM. Since the effective GEM gain is typically smaller than the absolute GEM gain, due to trapping of avalanche electrons at the bottom GEM electrode, the authors performed field simulations and measurements for better understanding, and discuss methods to eliminate this effect. Other performance parameters of the GEMs are also presented, including absolute GEM gain, short-term and long-term gain stabilities.

  7. Origins of GEMS Grains

    NASA Technical Reports Server (NTRS)

    Messenger, S.; Walker, R. M.

    2012-01-01

    Interplanetary dust particles (IDPs) collected in the Earth s stratosphere contain high abundances of submicrometer amorphous silicates known as GEMS grains. From their birth as condensates in the outflows of oxygen-rich evolved stars, processing in interstellar space, and incorporation into disks around new stars, amorphous silicates predominate in most astrophysical environments. Amorphous silicates were a major building block of our Solar System and are prominent in infrared spectra of comets. Anhydrous interplanetary dust particles (IDPs) thought to derive from comets contain abundant amorphous silicates known as GEMS (glass with embedded metal and sulfides) grains. GEMS grains have been proposed to be isotopically and chemically homogenized interstellar amorphous silicate dust. We evaluated this hypothesis through coordinated chemical and isotopic analyses of GEMS grains in a suite of IDPs to constrain their origins. GEMS grains show order of magnitude variations in Mg, Fe, Ca, and S abundances. GEMS grains do not match the average element abundances inferred for ISM dust containing on average, too little Mg, Fe, and Ca, and too much S. GEMS grains have complementary compositions to the crystalline components in IDPs suggesting that they formed from the same reservoir. We did not observe any unequivocal microstructural or chemical evidence that GEMS grains experienced prolonged exposure to radiation. We identified four GEMS grains having O isotopic compositions that point to origins in red giant branch or asymptotic giant branch stars and supernovae. Based on their O isotopic compositions, we estimate that 1-6% of GEMS grains are surviving circumstellar grains. The remaining 94-99% of GEMS grains have O isotopic compositions that are indistinguishable from terrestrial materials and carbonaceous chondrites. These isotopically solar GEMS grains either formed in the Solar System or were completely homogenized in the interstellar medium (ISM). However, the

  8. New Approach for 2D Readout of GEM Detectors

    SciTech Connect

    Hasell, Douglas K

    2011-10-29

    Detectors based on Gas Electron Multiplication (GEM) technology are becoming more and more widely used in nuclear and high energy physics and are being applied in astronomy, medical physics, industry, and homeland security. GEM detectors are thin, low mass, insensitive to magnetic fields, and can currently provide position resolutions down to {approx}50 microns. However, the designs for reconstructing the position, in two dimensions (2D), of the charged particles striking a GEM detector are often complicated to fabricate and expensive. The objective of this proposal is to investigate a simpler procedure for producing the two dimensional readout layer of GEM detectors using readily available printed circuit board technology which can be tailored to the detector requirements. We will use the established GEM laboratory and facilities at M.I.T. currently employed in developing GEM detectors for the STAR forward tracking upgrade to simplify the testing and evaluation of the new 2D readout designs. If this new design proves successful it will benefit future nuclear and high energy physics experiments already being planned and will similarly extend and simplify the application of GEM technology to other branches of science, medicine, and industry. These benefits would be not only in lower costs for fabrication but also it increased flexibility for design and application.

  9. The GEM Silicon Tracking System

    SciTech Connect

    Mills, G.B.

    1993-09-01

    The GEM Collaboration has produced a baseline design for the GEM detector. The baseline design of the GEM Silicon Tracking System (STS) is discussed in this article. Mechanical and electrical engineering progress on the GEM STS is described. Results from simulations of detector performance and the implications on engineering issues are described.

  10. Impact of GEM foil hole geometry on GEM detector gain

    NASA Astrophysics Data System (ADS)

    Karadzhinova, A.; Nolvi, A.; Veenhof, R.; Tuominen, E.; Hæggström, E.; Kassamakov, I.

    2015-12-01

    Detailed 3D imaging of Gas Electron Multiplier (GEM) foil hole geometry was realized. Scanning White Light Interferometry was used to examine six topological parameters of GEM foil holes from both sides of the foil. To study the effect of the hole geometry on detector gain, the ANSYS and Garfield ++ software were employed to simulate the GEM detector gain on the basis of SWLI data. In particular, the effective gain in a GEM foil with equally shaped holes was studied. The real GEM foil holes exhibited a 4% lower effective gain and 6% more electrons produced near the exit electrode of the GEM foil than the design anticipated. Our results indicate that the GEM foil hole geometry affects the gain performance of GEM detectors.

  11. Mit Mathematik zu Mehr Intelligenz in der Logistik

    NASA Astrophysics Data System (ADS)

    Möhring, Rolf H.; Schenk, Michael

    Die Lösung logistischer Probleme ist ein wichtiger Aspekt menschlichen Handelns seit Menschen gemeinsam zielgerichtet tätig wurden. Die Grundlagen dessen, was wir heute Logistik nennen, entstammen dem militärischen Bereich. So basierte z. B. das römische Imperium in starkem Maße auf militärisch-logistischen Glanzleistungen. Ob damals bereits mathematische Überlegungen eine Rolle spielten, wissen wir heute nicht. Jedoch versuchte z. B. Napoleon, der mit den bedeutendsten Mathematikern seiner Zeit befreundet war, den Transport seiner Truppen und die Verbreitung von Informationen zu optimieren und strategisch einzusetzen.1,2

  12. GEM Technical Design Report

    SciTech Connect

    Not Available

    1993-07-31

    The GEM collaboration was formed in June 1991 to develop a major detector for the SSC. The primary physics objectives of GEM are those central to the motivation for the SSC, to study high p{sub T} physics - exemplified by the search for Higgs bosons - and to search for new physics beyond the standard model. The authors present in this Technical Design Report (TDR) a detector with broad capabilities for the discovery and subsequent study of electroweak symmetry breaking, the origin of mass and flavor, and other physics requiring precise measurements of gammas, electrons, and muons - hence the name, GEM. In addition, as a design goal, they have taken care to provide the robustness needed to do the physics that requires high luminosity. Finally, good coverage and hermeticity allow the detection of missing transverse energy, E{sub T}. The GEM design emphasizes clean identification and high resolution measurement of the primary physics signatures for high p{sub T} physics. The approach is to make precise energy measurements that maximize the sensitivity to rare narrow resonances, to detect the elementary interaction products (quarks, leptons, and photons), and to build in the features required to reduce backgrounds.

  13. A Hidden GEM

    ERIC Educational Resources Information Center

    Khan, Samia

    2012-01-01

    The internet abounds with free science education applications. But, on their own, these applications have limited capacity to teach students curricular concepts or skills. The author integrated several free web-based applications into a broader pedagogical approach called T-GEM, in which the teacher guides student investigations. In this article,…

  14. Progress on large area GEMs

    NASA Astrophysics Data System (ADS)

    Villa, Marco; Duarte Pinto, Serge; Alfonsi, Matteo; Brock, Ian; Croci, Gabriele; David, Eric; de Oliveira, Rui; Ropelewski, Leszek; Taureg, Hans; van Stenis, Miranda

    2011-02-01

    The Gas Electron Multiplier (GEM) manufacturing technique has recently evolved to allow the production of large area GEMs. A novel approach based on single mask photolithography eliminates the mask alignment issue, which limits the dimensions in the traditional double mask process. Moreover, a splicing technique overcomes the limited width of the raw material. Stretching and handling issues in large area GEMs have also been addressed. Using the new improvements it was possible to build a prototype triple-GEM detector of ˜2000 cm2 active area, aimed at an application for the TOTEM T1 upgrade. Further refinements of the single mask technique allow great control over the shape of the GEM holes and the size of the rims, which can be tuned as needed. In this framework, simulation studies can help to understand the GEM behavior depending on the hole shape.

  15. The performance of Glass GEM

    NASA Astrophysics Data System (ADS)

    Fujiwara, T.; Mitsuya, Y.; Takahashi, H.; Fushie, T.; Kishimito, S.; Guèrard, B.; Uesaka, M.

    2014-11-01

    Here we report the performance of Glass gas electron multipliers (Glass GEMs), which were fabricated with photo-etchable glass. The photo-etchable glass used for substrate is called PEG3 (Hoya Corporation). With this material, we succeeded in fabricating a Glass GEM that was 680 μ m-thick with a hole diameter of 170 μ m and Cr and Cu layer electrodes. A Glass GEM has advantages such as good uniformity, high gain, a flat surface without stretching, cylindrical holes, and the absence of outgassing from the material. We successfully operated a Glass GEM having 100 × 100 m 2 effective area with various gas mixtures. The energy resolution for 5.9 keV X-rays was 18%, obtained by uniform irradiation of the entire effective area. The gas gain of the Glass GEM reached up to 90,000 with a gas mixture of Ne/C 4 (90:10). The Glass GEM was also operated with Ar/C 4 and Ar/C 4 gas. The gain stability measured for Glass GEM showed no significant increase or decrease as a function of elapsed time from applying high voltage. The gain stability over 15 hours of operation was about 10% in high-count-rate irradiation. Gain mapping across the Glass GEM showed good uniformity with a standard deviation of about 10%.

  16. Characterisations of GEM detector prototype

    NASA Astrophysics Data System (ADS)

    Patra, Rajendra Nath; Nanda, Amit; Rudra, Sharmili; Bhattacharya, P.; Sahoo, Sumanya Sekhar; Biswas, S.; Mohanty, B.; Nayak, T. K.; Sahu, P. K.; Sahu, S.

    2016-07-01

    At NISER-IoP detector laboratory an initiative is taken to build and test Gas Electron Multiplier (GEM) detectors for ALICE experiment. The optimisation of the gas flow rate and the long-term stability test of the GEM detector are performed. The method and test results are presented.

  17. On the Origin of GEMS

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Messenger, S.

    2004-01-01

    GEMS (glass with embedded metal and sulfides) are a major component of anhydrous interplanetary dust particles (IDPs) their physical and chemical characteristics show marked similarities to contemporary interstellar dust. Recent oxygen isotopic measurements confirm that at least a small fraction (less than 5%) of GEMS are demonstrably presolar, while the remainder have ratios that are indistinguishable from solar values. GEMS with solar oxygen isotopic compositions either (1) had their isotopic compositions homogenized through processing in the interstellar medium (ISM), or (2) formed in the early solar system. Isotopic homogenization necessarily implies chemical homogenization, so (interstellar) GEMS compositions should reflect the average composition of dust in the local ISM. We performed a systematic examination of the bulk chemistry of GEMS in primitive IDPs in order to test this hypothesis.

  18. Deep-Sky Companions: Southern Gems

    NASA Astrophysics Data System (ADS)

    O'Meara, Stephen James

    2013-05-01

    Preface; 1. How to use this book; 2. The southern gems; Appendix A. Southern gems: basic data; Appendix B. Forty-two additional southern gems in Dunlop's catalogue; Appendix C. A brief history of early telescopic exploration of the far-southern skies; Appendix D. Photo credits; The southern gems checklist; Index; Wide-field star charts.

  19. Giotto Extended Mission (GEM)

    NASA Technical Reports Server (NTRS)

    Wilkins, D. E. B.; Grensemann, M.

    1991-01-01

    The primary objectives of the Giotto Extended Mission (GEM), are to determine the composition and physical state of the Grigg Skjellerup Comet's nucleus; to determine the processes that govern the composition and distribution of neutral and ionized species in the cometary atmosphere. Giotto consists of a single European Space Agency (ESA) spacecraft that was launched in 1985 from Center Spatial Guyanis in French Guiana on an Ariane launch vehicle. After a successful launch into geostationary orbit and a heliocentric transfer trajectory, the spacecraft successfully encountered Halley's Comet in 1986. One month after encountering Halley's Comet, Mar. 1986, the spacecraft was placed in hibernation in a heliocentric orbit slightly less than 1 AU. Between Feb. and Jul. 1990 the spacecraft was successfully reactivated, checked out, and placed on a trajectory course to intercept comet Grigg Skjellerup. The spacecraft has been in hibernation since Jul. 1990. Information is presented in tabular form in the following areas: coverage goals, Deep Space Network Support, frequency assignments, telemetry, command, and tracking support responsibility.

  20. Origin and properties of GEMS

    SciTech Connect

    Dai, Z R; Bradley, J P

    2006-04-11

    GEMS are to the outer solar system what chondrules are to the inner solar system. Ten years after it was first proposed that GEMS are the long-sought interstellar amorphous silicates, ion microprobe measurements have confirmed that some of them are indeed interstellar amorphous silicates. The new challenges are to obtain even higher precision isotope measurements from these submicrometer-sized objects and to clarify how and where they originally formed. Individual GEMS exhibit a strikingly narrow (0.1-0.5 {micro}m diameter) size distribution and they are systematically depleted from solar abundances in S/Si, Mg/Si, Ca/Si and Fe/Si, implying that they formed by a common mechanism. Mineralogical and petrographic evidence suggest that irradiation processing may be that mechanism. Recent nanometer-scale compositional mapping using new-generation transmission electron microscopes reveals that truly pristine GEMS may be relatively rare and new metrics need to be developed to distinguish the primordial properties of GEMS from more recent secondary alteration effects.

  1. Representation of Clinical Nursing Protocols Using GEM II & GEM Cutter

    PubMed Central

    Koch, Karen A.; Woodcock, Michael W.; Harris, Marcelline R.

    2010-01-01

    The machineable representation and execution of clinical guidelines has been the focus of research efforts for some time, however there is less examination of whether the methods and techniques for guidelines are sufficient for clinical protocols. The objective of this study was to test the feasibility of using the Guideline Elements Model II (GEM II) and GEM Cutter for the representation of clinical protocols, specifically clinical protocols commonly used by nurses. After downloading the GEM Cutter 2.5, we decomposed a set of clinical protocols and analyzed the completeness in which elemental protocol data was represented. One of the most complicated of these protocols (extravasations of infused medication) is presented as an example. While GEM II adequately represents core elements of clinical protocols at the high level, it was not possible to adequately represent sequence and associated role based permissions via use of conditional criteria at branching and procedural levels. Functionality of the tool would also be enhanced with more robust terminology management and support for multi-authoring. PMID:21347008

  2. The GEMS Kit Builder's Handbook.

    ERIC Educational Resources Information Center

    Goodman, Jan; Sneider, Cary; Gould, Alan; Barber, Jacqueline; Hosoume, Kimi; Tucker, Laura; Willard, Carolyn

    For many educators, gathering, organizing, and maintaining materials involved in inquiry-based science and math activities can seem daunting. This handbook is designed to help teachers in the task of gathering and maintaining materials to make kits for 42 activities derived from the Great Explorations in Math and Science (GEMS) Program at the…

  3. GEM - The Global Earthquake Model

    NASA Astrophysics Data System (ADS)

    Smolka, A.

    2009-04-01

    Over 500,000 people died in the last decade due to earthquakes and tsunamis, mostly in the developing world, where the risk is increasing due to rapid population growth. In many seismic regions, no hazard and risk models exist, and even where models do exist, they are intelligible only by experts, or available only for commercial purposes. The Global Earthquake Model (GEM) answers the need for an openly accessible risk management tool. GEM is an internationally sanctioned public private partnership initiated by the Organisation for Economic Cooperation and Development (OECD) which will establish an authoritative standard for calculating and communicating earthquake hazard and risk, and will be designed to serve as the critical instrument to support decisions and actions that reduce earthquake losses worldwide. GEM will integrate developments on the forefront of scientific and engineering knowledge of earthquakes, at global, regional and local scale. The work is organized in three modules: hazard, risk, and socio-economic impact. The hazard module calculates probabilities of earthquake occurrence and resulting shaking at any given location. The risk module calculates fatalities, injuries, and damage based on expected shaking, building vulnerability, and the distribution of population and of exposed values and facilities. The socio-economic impact module delivers tools for making educated decisions to mitigate and manage risk. GEM will be a versatile online tool, with open source code and a map-based graphical interface. The underlying data will be open wherever possible, and its modular input and output will be adapted to multiple user groups: scientists and engineers, risk managers and decision makers in the public and private sectors, and the public-at- large. GEM will be the first global model for seismic risk assessment at a national and regional scale, and aims to achieve broad scientific participation and independence. Its development will occur in a

  4. MIT: Shaping the Future.

    ERIC Educational Resources Information Center

    Manning, Kenneth R., Ed.

    This book provides 16 essays by faculty and staff of the Massachusetts Institute of Technology (MIT) concerning what MIT is like today and offering a guide to its possible future. Emphasis is placed on local, national, and global issues, providing a current sampling of the state of concerns and opinions around MIT. Topics include the question of…

  5. Mining for Gems: The Making of Readers and Writers.

    ERIC Educational Resources Information Center

    Thomas, Pat

    2000-01-01

    Considers how to develop students' passion for language and how to get them to stop and look at word choice. Defines a "gem" as a word, phrase, or sentence that is particularly remarkable or moving. Describes working with students to notice the gems, design gem journals, write their own gems, and to create future gems. (SC)

  6. Introduction: ISC-GEM catalog

    NASA Astrophysics Data System (ADS)

    Helffrich, George

    2015-02-01

    This Special Issue of Physics of the Earth and Planetary Interiors documents the intent, logistical efforts and methods used in producing the ISC-GEM Global Instrumental Earthquake Catalog (1900-2009). It represents a significant achievement in both the manpower and the methods used to yield a homogeneous catalog from the earliest days of global seismic instrumentation. The catalog should present researchers with a resource to assess seismicity rates, locations and mechanisms uniformly in the instrumental era.

  7. GEM: The GAAIN Entity Mapper

    PubMed Central

    Dewan, Peehoo; Ambite, Jose-Luis; Toga, Arthur W.

    2015-01-01

    We present a software system solution that significantly simplifies data sharing of medical data. This system, called GEM (for the GAAIN Entity Mapper), harmonizes medical data. Harmonization is the process of unifying information across multiple disparate datasets needed to share and aggregate medical data. Specifically, our system automates the task of finding corresponding elements across different independently created (medical) datasets of related data. We present our overall approach, detailed technical architecture, and experimental evaluations demonstrating the effectiveness of our approach. PMID:26665184

  8. Leading a successful iGEM team.

    PubMed

    Materi, Wayne

    2012-01-01

    The International Genetically Engineered Machines (iGEM) competition allows undergraduate teams to develop projects in synthetic biology within the context of a large, international Jamboree. Organizing and managing a successful iGEM team is an exercise in advanced agile project development. While many of the principles applicable to such teams are derived from management of agile software teams, iGEM presents several unique challenges. PMID:22328439

  9. The GEMS-2 SEIS Experiment

    NASA Astrophysics Data System (ADS)

    Tillier, S.; De Raucourt, S.; Mimoun, D.; Lognonne, P.; Giardini, D.; Christensen, U. R.; Pike, W. T.; Banerdt, B.; Laudet, P.; Kerjean, L.; Hurst, K. J.; Zweifel, P.; Mance, D.; Roll, R.; Bierwirth, M.; Gagnepain-Beyneix, J.; Nibut, T.; Robert, O.; Gabsi, T.; Pot, O.; Lecomte, B.; Schibler, P.; Mocquet, A.; Garcia, R.

    2011-12-01

    The SEIS experiment is the primary payload of the Geophysical Monitoring Station (GEMS) Mission Proposal, submitted to NASA in the frame of the 2010 Discovery program, and recently selected for the phase A study. The objective of the GEMS SEIS experiment is the determination of the deep internal structure of Mars. In particular, geophysical parameters of first importance, such as the state (liquid/solid) and size of the core, as well as structure of the mantle and shape of discontinuities will be determined by the experiment. It will measure seismic activity in a very broad band of signal, from the tidal frequencies (0.05 mHz) up to the short period frequencies (50 Hz), to address the widest range of scientific questions, from the state of the inner core to the meteoritic rate measurement. Infrasound, which might be associated to dust devils and atmospheric discharge, will be also monitored. The instrument integrates a Very Broad Band (VBB) 3 axis seismometer, completed by another trihedron of MEMS short period seismometers, environmental sensors for pressure, wind and temperature, and an infrasound sensor is additionally considered. The sensors will be deployed on the Martian ground by a robotic arm from the Phoenix lander platform and protected by a wind and thermal shield. The sensor assembly, which contains all seismic sensors, the leveling system, as well as house-keeping and temperature measurements, will be deployed on the soil in order to allow the best possible mechanical coupling with the ground motion. Thanks to the wind and thermal shield, together with the sensors' specific containers (vacuum sphere for VBBs), long term VBB bias will be protected from both temperature and pressure variations (as well as passively compensated), allowing the sensor to operate in the rough Martian thermal environment. A dedicated electronics will manage the overall experiment and ultra-low noise, space qualified 24 bits A/D converters will perform the acquisition. The

  10. GEM: Statistical weather forecasting procedure

    NASA Technical Reports Server (NTRS)

    Miller, R. G.

    1983-01-01

    The objective of the Generalized Exponential Markov (GEM) Program was to develop a weather forecast guidance system that would: predict between 0 to 6 hours all elements in the airways observations; respond instantly to the latest observed conditions of the surface weather; process these observations at local sites on minicomputing equipment; exceed the accuracy of current persistence predictions at the shortest prediction of one hour and beyond; exceed the accuracy of current forecast model output statistics inside eight hours; and be capable of making predictions at one location for all locations where weather information is available.

  11. ROLE OF GEMS IN INDIAN MEDICINE

    PubMed Central

    Murthy, S.R.N.

    1991-01-01

    This paper is the first attempt in introducing the medicinal importance of gems as found in the Sanskrit text ‘Rasaratnasamuccaya’, which has been rendered an English translation here. The modern physicians and gemologists will find this study quite useful in continuing research and, thus, develop a new field of gem medicine. PMID:22556526

  12. REGISTRATION OF MAIZE GERMPLASM LINE GEMS-0067

    Technology Transfer Automated Retrieval System (TEKTRAN)

    GEMS-0067 is a partially inbred germplasm line released by Truman State University (TSU) in accordance with the Germplasm Enhancement of Maize (GEM) protocol. This line is being released for use in the development of genetically diverse, elite, amylomaize class VII parental lines possessing modifie...

  13. Germplasm Enhancement of Maize (GEM) Project Overview

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Germplasm Enhancement of Maize Project (GEM) is a collaborative effort of public and private sector researchers to broaden and enhance the maize germplasm base. The GEM Project has cooperators from 26 private companies, 17 Universities, 7 USDA-ARS Research Units, 1 NGO, and 12 international pub...

  14. The GEM-T2 gravitational model

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Lerch, F. J.; Putney, B. H.; Felsentreger, T. L.; Sanchez, B. V.; Klosko, S. M.; Patel, G. B.; Robbins, J. W.; Williamson, R. G.; Engelis, T. E.

    1989-01-01

    The GEM-T2 is the latest in a series of Goddard Earth Models of the terrestrial field. It was designed to bring modeling capabilities one step closer towards ultimately determining the TOPEX/Poseidon satellite's radial position to an accuracy of 10-cm RMS (root mean square). It also improves models of the long wavelength geoid to support many oceanographic and geophysical applications. The GEM-T2 extends the spherical harmonic field to include more than 600 coefficients above degree 36 (which was the limit for its predecessor, GEM-T1). Like GEM-T1, it was produced entirely from satellite tracking data, but it now uses nearly twice as many satellites (31 vs. 17), contains four times the number of observations (2.4 million), has twice the number of data arcs (1132), and utilizes precise laser tracking from 11 satellites. The estimation technique for the solution has been augmented to include an optimum data weighting procedure with automatic error calibration for the gravitational parameters. Results for the GEM-T2 error calibration indicate significant improvement over previous satellite-only models. The error of commission in determining the geoid has been reduced from 155 cm in GEM-T1 to 105 cm for GEM-T2 for the 36 x 36 portion of the field, and 141 cm for the entire model. The orbital accuracies achieved using GEM-T2 are likewise improved. Also, the projected radial error on the TOPEX satellite orbit indicates 9.4 cm RMS for GEM-T2, compared to 24.1 cm for GEM-T1.

  15. The GEM-T2 gravitational model

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Lerch, F. J.; Putney, B. H.; Felsentreger, T. L.; Sanchez, B. V.

    1990-01-01

    The GEM-T2 is the latest in a series of Goddard Earth Models of the terrestrial field. It was designed to bring modeling capabilities one step closer towards ultimately determining the TOPEX/Poseidon satellite's radial position to an accuracy of 10-cm RMS (root mean square). It also improves models of the long wavelength geoid to support many oceanographic and geophysical applications. The GEM-T2 extends the spherical harmonic field to include more than 600 coefficients above degree 36 (which was the limit for its predecessor, GEM-T1). Like GEM-T1, it was produced entirely from satellite tracking data, but it now uses nearly twice as many satellites (31 vs. 17), contains four times the number of observations (2.4 million), has twice the number of data arcs (1132), and utilizes precise laser tracking from 11 satellites. The estimation technique for the solution has been augmented to include an optimum data weighting procedure with automatic error calibration for the gravitational parameters. Results for the GEM-T2 error calibration indicate significant improvement over previous satellite-only models. The error of commission in determining the geoid has been reduced from 155 cm in GEM-T1 to 105 cm for GEM-T2 for the 36 x 36 portion of the field, and 141 cm for the entire model. The orbital accuracies achieved using GEM-T2 are likewise improved. Also, the projected radial error on the TOPEX satellite orbit indicates 9.4 cm RMS for GEM-T2, compared to 24.1 cm for GEM-T1.

  16. A GEM of a Resource: The Gateway to Educational Materials.

    ERIC Educational Resources Information Center

    Tickner, Marilyn; Barkhouse, Nancy

    2001-01-01

    Describes GEM (Gateway to Educational Materials) that provides easy, fast, and free access to lesson plans, curriculum units, and other educational materials on the Internet. Discusses interaction between users and content providers; GEM versus search engines; how a GEM record is created; and the metadata used in GEM records. (LRW)

  17. Commercial and Cost Effective Production of Gas Electron Multiplier (GEM) Foils

    SciTech Connect

    Woody, Craig

    2009-03-31

    The nuclear and high energy physics research community is constantly searching for new and improved tracking and radiation detectors. The introduction of micropattern detectors has opened new opportunities for improving the rate capabilities, as well as the spatial and time resolution of particle detectors in these applications. GEM detectors in particular have received enormous interest for use in detectors planned for a number of new and upgraded experiments at many different research facilities. These include both the STAR and PHENIX experiments at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, experiments at the Thomas Jefferson National Laboratory, Oak Ridge National Laboratory, and at the future electron-positron Linear Collider. At the present time, CERN is not able to supply foils in sufficient quantities to accommodate the needs of these experiments. Compounding this problem, there is a strong interest in GEM foils for numerous other applications, such as in astrophysics, medical imaging and detectors for homeland security. It would therefore be of significant benefit to the research community to develop a commercial source of GEM foils for all of these applications. Tech-Etch is in a unique position to develop this technology for commercial use. Tech-Etch has not only experience in numerous related high precision etched Kapton® products, but it also has strong ties with several research institutions (namely Brookhaven, Yale and MIT) that can help develop and evaluate the performance of the GEM foils produced at Tech-Etch. Additionally, since Tech-Etch is a small company, it also has the capability to produce a large variety of part configurations, as well as the flexibility to shift production methods, equipment, and chemistry to optimize the GEM foil manufacturing process without being constrained by existing work running on high volume continuous coil equipment.

  18. Commercial and cost effective production of Gas Electron Multiplier (GEM) Foils

    SciTech Connect

    Crary, David

    2010-05-05

    The nuclear and high energy physics research community is constantly searching for new and improved tracking and radiation detectors. The introduction of micropattern detectors has opened new opportunities for improving the rate capabilities, as well as the spatial and time resolution of particle detectors in these applications. GEM detectors in particular have received enormous interest for use in detectors planned for a number of new and upgraded experiments at many different research facilities. These include both the STAR and PHENIX experiments at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, experiments at the Thomas Jefferson National Laboratory, Oak Ridge National Laboratory, and at the future electron-positron Linear Collider. At the present time, CERN is not able to supply foils in sufficient quantities to accommodate the needs of these experiments. Compounding this problem, there is a strong interest in GEM foils for numerous other applications, such as in astrophysics, medical imaging and detectors for homeland security. It would therefore be of significant benefit to the research community to develop a commercial source of GEM foils for all of these applications. Tech-Etch is in a unique position to develop this technology for commercial use. Tech-Etch has not only experience in numerous related high precision etched Kapton® products, but it also has strong ties with several research institutions (namely Brookhaven, Yale and MIT) that can help develop and evaluate the performance of the GEM foils produced at Tech-Etch. Additionally, since Tech-Etch is a small company, it also has the capability to produce a large variety of part configurations, as well as the flexibility to shift production methods, equipment, and chemistry to optimize the GEM foil manufacturing process without being constrained by existing work running on high volume continuous coil equipment.

  19. GEMS: Building Blocks of the Solar System

    NASA Astrophysics Data System (ADS)

    Ishii, H. A.; Bradley, J. P.; Wozniakiewicz, P. J.; Noguchi, T.; Dobrica, E.; Engrand, C.; Brownlee, D. E.

    2014-09-01

    Upon consideration of terrestrial alteration effects and instrumental limitations, we find that GEMS, glass with embedded metal and sulfides, in cometary dust remain the best candidate for surviving interstellar amorphous silicates.

  20. The GEMS Model of Volunteer Administration.

    ERIC Educational Resources Information Center

    Culp, Ken, III; Deppe, Catherine A.; Castillo, Jaime X.; Wells, Betty J.

    1998-01-01

    Describes GEMS, a spiral model that profiles volunteer administration. Components include Generate, Educate, Mobilize, and Sustain, four sets of processes that span volunteer recruitment and selection to retention or disengagement. (SK)

  1. Data Analysis And Polarization Measurements With GEMS

    NASA Technical Reports Server (NTRS)

    Stohmayer, Tod

    2011-01-01

    The Gravity and Extreme Magnetism SMEX (GEMS) mission was selected by NASA for flight in 2014. GEMS will make the first sensitive survey of X-ray polarization across a wide range of source classes including black hole and neutron star binaries, AGN of different types, rotation and accretion-powered pulsars, magnetars, shell supernova remnants and pulsar wind nebulae. GEMS employs grazing-incidence foil mirrors and novel time-projection chamber (TPC) polarimeters leveraging the photoelectric effect. The GEMS detectors image the charge tracks of photoelectrons produced by 2 - 10 keV X-rays. The initial direction of the photoelectron is determined by the linear polarization of the photon. We present an overview of the data analysis challenges and methods for GEMS, including procedures for producing optimally filtered images of the charge tracks and estimating their initial directions. We illustrate our methods using laboratory measurements of polarized and unpolarized X-rays with flight-like detectors as well as from simulated tracks. We also present detailed simulations exploring the statistics of polarization measurements appropriate for GEMS, and make comparisons with previous work.

  2. Gas Electron Multiplier (GEM) Chamber Characteristics Test

    SciTech Connect

    Yu, Jaehoon; White, Andy; Park, Seongtae; Hahn, Changhie; Baldeloma, Edwin; Tran, Nam; McIntire, Austin; Soha, Aria; /Fermilab

    2011-01-11

    Gas Electron Multipliers (GEMs) have been used in many HEP experiments as tracking detectors. They are sensitive to X-rays which allows use beyond that of HEP. The UTA High Energy group has been working on using GEMs as the sensitive gap detector in a DHCAL for the ILC. The physics goals at the ILC put a stringent requirement on detector performance. Especially the precision required for jet mass and positions demands an unprecedented jet energy resolution to hadronic calorimeters. A solution to meet this requirement is using the Particle Flow Algorithm (PFA). In order for PFA to work well, high calorimeter granularity is necessary. Previous studies based on GEANT simulations using GEM DHCAL gave confidence on the performance of GEM in the sensitive gap in a sampling calorimeter and its use as a DHCAL in PFA. The UTA HEP team has built several GEM prototype chambers, including the current 30cm x 30cm chamber integrated with the SLAC-developed 64 channel kPiX analog readout chip. This chamber has been tested on the bench using radioactive sources and cosmic ray muons. In order to have fuller understanding of various chamber characteristics, the experiments plan to expose 1-3 GEM chambers of dimension 35cm x 35cm x 5cm with 1cm x 1cm pad granularity with 64 channel 2-D simultaneous readout using the kPiX chip. In this experiment the experiments pan to measure MiP signal height, chamber absolute efficiencies, chamber gain versus high voltage across the GEM gap, the uniformity of the chamber across the 8cm x 8cm area, cross talk and its distance dependence to the triggered pad, chamber rate capabilities, and the maximum pad occupancy rate.

  3. MPD work at MIT

    NASA Technical Reports Server (NTRS)

    Martinez-Sanchez, Manuel

    1991-01-01

    MPD work at MIT is presented in the form of the view-graphs. The following subject areas are covered: the MIT program, its goals, achievements, and roadblocks; quasi one-dimensional modeling; two-dimensional modeling - transport effects and Hall effect; microscopic instabilities in MPD flows and modified two stream instability; electrothermal stability theory; separation of onset and anode depletion; exit plane spectroscopic measurements; phenomena of onset as performance limiter; explanations of onset; geometry effects on onset; onset at full ionization and its consequences; relationship to anode depletion; summary on self-field MPD; applied field MPD - the logical growth path; the case for AF; the challenges of AF MPD; and recommendations.

  4. Does Comet WILD-2 contain Gems?

    NASA Technical Reports Server (NTRS)

    Chi, M.; Ishii, H.; Dai, Z. R.; Toppani, A.; Joswiak, D. J.; Leroux, H.; Zolensky, M.; Keller, L. P.; Browning, N. D.

    2007-01-01

    It is expected that Comet Wild-2 dust should resemble anhydrous carbon-rich, chondritic porous (CP) interplanetary dust particles (IDPs) collected in the stratosphere because some CP IDPs are suspected to be from comets. The rarity of carbonaceous grains and presolar silicates, as well as the presence of high-temperature inner solar nebula minerals in the Wild-2 sample (e.g. osbornite and melilite), appear incompatible with most CP IDPs. However, it is premature to draw firm conclusions about the mineralogy of comet Wild-2 because only approx. 1% of the sample has been examined. The most abundant silicates in CP IDPs are GEMS (glass with embedded metal and sulfides). Nonsolar O isotopic compositions confirm that at least some GEMS in IDPs are presolar amorphous silicates. The presence or absence of GEMS in the Wild-2 sample is important because it addresses, (a) the relationship between CP IDPs and comets, and (b) the hypothesis that other GEMS in IDPs formed in the solar nebula. Here we show that most of the GEMSlike materials so far identified in Stardust aerogel were likely impact generated during collection. At the nanometer scale, they are compositionally and crystallographically distinct from GEMS in IDPs.

  5. Optical quality assurance of GEM foils

    NASA Astrophysics Data System (ADS)

    Hildén, T.; Brücken, E.; Heino, J.; Kalliokoski, M.; Karadzhinova, A.; Lauhakangas, R.; Tuominen, E.; Turpeinen, R.

    2015-01-01

    An analysis software was developed for the high aspect ratio optical scanning system in the Detector Laboratory of the University of Helsinki and the Helsinki Institute of Physics. The system is used e.g. in the quality assurance of the GEM-TPC detectors being developed for the beam diagnostics system of the SuperFRS at future FAIR facility. The software was tested by analyzing five CERN standard GEM foils scanned with the optical scanning system. The measurement uncertainty of the diameter of the GEM holes and the pitch of the hole pattern was found to be 0.5 μm and 0.3 μm, respectively. The software design and the performance are discussed. The correlation between the GEM hole size distribution and the corresponding gain variation was studied by comparing them against a detailed gain mapping of a foil and a set of six lower precision control measurements. It can be seen that a qualitative estimation of the behavior of the local variation in gain across the GEM foil can be made based on the measured sizes of the outer and inner holes.

  6. Abdichtungen mit Bitumenbahnen

    NASA Astrophysics Data System (ADS)

    Rahn, Axel C.; Unger, Wolfram

    Das Werk Bauwerksabdichtung von Karl Lufsky, im allgemeinen Sprachgebrauch auch Der Lufsky genannt, war immer das Standardwerk für Flächenabdichtungen mit Bitumenwerkstoffen. Karl Lufsky war erst Mitarbeiter des Geschäftsführers Otto Latendorf der 1924 in Berlin gegründeten Firma ARIDO Abdichtungs-GmbH und später ihr Geschäftsführer [8.1]. Eine Baustelle war seit 1950 der Keller der neuen Sowjetischen Botschaft Unter den Linden. Eines Tages sprach dort einer der russischen Ingenieur-Offiziere Otto Latendorf an und fragte ihn, ob er wohl eine schriftliche Zusammenfassung aller technischen Probleme der bituminösen Bauwerksabdichtung für ihn verfassen könnte. Mit dieser Schrift würde er sich dann zu seinem Abschlussexamen in Moskau melden. Vergüten wollte er den Arbeitsaufwand mit Lebensmittellieferungen. Otto Latendorf willigte ein und machte sich gemeinsam mit Karl Lufsky an die Arbeit. Dies war offensichtlich der Impuls für Karl Lufsky, einige Zeit später im Leipziger Teubner Verlag die erste Auflage des Buchs "Bauwerksabdichtungen“ herauszugeben, womit der Grundstein gelegt wurde, aus einer "Moskauer Examensarbeit“ in den letzten 50 Jahren ein bedeutendes Fachbuch zu machen.

  7. An implementation framework for GEM encoded guidelines.

    PubMed Central

    Gershkovich, P.; Shiffman, R. N.

    2001-01-01

    Access to timely decision support information is critical for delivery of high-quality medical care. Transformation of clinical knowledge that is originally expressed in the form of a guideline to a computable format is one of the main obstacles to the integration of knowledge sharing functionality into computerized clinical systems. The Guideline Element Model (GEM) provides a methodology for such a transformation. Although the model has been used to store heterogeneous guideline knowledge, it is important to demonstrate that GEM markup facilitates guideline implementation. This report demonstrates the feasibility of implementation of GEM-encoded guideline recommendations using Apache Group s Cocoon Web Publishing Framework. We further demonstrate how XML-based programming allows for maintaining the separation of guideline content from processing logic and from presentation format. Finally, we analyze whether the guideline authors original intent has been sufficiently captured and conveyed to the end user. PMID:11825181

  8. Development of a GEM Electronic Board (GEB) for triple-GEM detectors

    NASA Astrophysics Data System (ADS)

    Aspell, P.; Dabrowski, M.; Conde Garcia, A.; De Lentdecker, G.; Marinov, A.; De Oliveira, R.; Talvitie, J.; Tuuva, T.; Yang, Y.

    2014-12-01

    Developed for use with triple GEM detectors, the GEM Electronic Board (GEB) forms a crucial part of the electronics readout system being developed as part of the CMS muon upgrade program. The objective of the GEB is threefold; to provide stable powering and ground for the VFAT3 front ends, to enable high-speed communication between 24 VFAT3 front ends and an optohybrid, and to shield the GEM detector from electromagnetic interference. The paper describes the concept and design of a large-size GEB in detail, highlighting the challenges in terms of design and feasibility of this deceptively difficult system component.

  9. Neutron beam imaging with GEM detectors

    NASA Astrophysics Data System (ADS)

    Albani, G.; Croci, G.; Cazzaniga, C.; Cavenago, M.; Claps, G.; Muraro, A.; Murtas, F.; Pasqualotto, R.; Perelli Cippo, E.; Rebai, M.; Tardocchi, M.; Gorini, G.

    2015-04-01

    Neutron GEM-based detectors represent a new frontier of devices in neutron physics applications where a very high neutron flux must be measured such as future fusion experiments (e.g. ITER Neutral beam Injector) and spallation sources (e.g. the European Spallation source). This kind of detectors can be properly adapted to be used both as beam monitors but also as neutron diffraction detectors that could represent a valid alternative for the 3He detectors replacement. Fast neutron GEM detectors (nGEM) feature a cathode composed by one layer of polyethylene and one of aluminium (neutron scattering on hydrogen generates protons that are detected in the gas) while thermal neutron GEM detectors (bGEM) are equipped with a borated aluminium cathode (charged particles are generated through the 10B(n,α)7Li reaction). GEM detectors can be realized in large area (1 m2) and their readout can be pixelated. Three different prototypes of nGEM and one prototype of bGEM detectors of different areas and equipped with different types of readout have been built and tested. All the detectors have been used to measure the fast and thermal neutron 2D beam image at the ISIS-VESUVIO beamline. The different kinds of readout patterns (different areas of the pixels) have been compared in similar conditions. All the detectors measured a width of the beam profile consitent with the expected one. The imaging property of each detector was then tested by inserting samples of different material and shape in the beam. All the samples were correctly reconstructed and the definition of the reconstruction depends on the type of readout anode. The fast neutron beam profile reconstruction was then compared to the one obtained by diamond detectors positioned on the same beamline while the thermal neutron one was compared to the imaged obtained by cadmium-coupled x-rays films. Also efficiency and the gamma background rejection have been determined. These prototypes represent the first step towards the

  10. The GEMS-2 Seis Experiment

    NASA Astrophysics Data System (ADS)

    Mimoun, D.; de Raucourt, S.; Lognonne, P.; Giardini, D.; Christensen, U. R.; Gagnepain-Beyneix, J.; Pike, T.; Nebut, T.; Tillier, S.; Robert, O.; Gabsi, T.; Pot, O.; Lecomte, B.; Escande, N.; Mocquet, A.; Zweifel, P.; Mance, D.; Roll, R.; Bierwirth, M.

    2010-12-01

    of data will be made on the basis of raw compressed data, plus an excerpt of the high frequency events of the day. The proposed instrument has been developed up to PDR in the frame of the ExoMars Humbold payload. Most critical parts have been tested, including shock tests for pivot, electronics components and displacement sensors. TRL 6 is expected at the end of 2011. SEIS has been proposed onboard the GEMS Mission Proposal, submitted to NASA in the frame of the 2010 Discovery AO.

  11. Gravitational field modes GEM 3 and 4

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Wagner, C. A.; Putney, B. H.; Sandson, M. L.; Brownd, J. E.; Richardson, J. A.; Taylor, W. A.

    1972-01-01

    A refinement in the satellite geopotential solution for a Goddard Earth Model (GEM 3) was obtained. The solution includes the addition of two low inclination satellites, SAS at 3 deg and PEOLE at 15 deg, and is based upon 27 close earth satellites containing some 400,000 observations of electronic, laser, and optical data. In addition, a new combination satellite/gravimetry solution (GEM 4) was derived. The new model includes 61 center of mass tracking station locations with data from GRARR, Laser, MOTS, Baker-Nunn, and NWL Tranet Doppler tracking sites. Improvement was obtained for the zonal coefficients of the new models and is shown by tests on the long period perturbations of the orbits. Individual zonal coefficients agree very closely among different models that contain low inclination satellites. Tests of models with surface gravity data show that the GEM 3 satellite model has significantly better agreement with the gravimetry data than the GEM 1 satellite model, and that it also has better agreement with the gravimetry data than the 1969 SAO Standard Earth 2 model.

  12. Performance of the GEM electromagnetic calorimeter

    SciTech Connect

    Hong Ma

    1993-06-25

    The GEM EM calorimeter is optimized for the best energy, position, angular resolution and jet rejection. The detailed simulation results are presented. In the barrel with LKr, an energy resolution of about 6%/{radical}{direct_sum}0.4%, pointing resolution of 40mrad/{radical}E + 0.5mrad, and jet rejection of a factor of 5 are expected.

  13. Development of GEMs at Hampton University

    NASA Astrophysics Data System (ADS)

    Liyanage, Anusha; Kohl, Michael; MUSE Collaboration

    2015-10-01

    Two GEM telescopes each consisting of three 10×10 cm2 triple-GEM chambers 30-40 cm apart were built, tested and operated by the Hampton group. They are read out with APV25 frontend chips and FPGA based digitizing electronics developed by INFN Rome. The telescopes served as luminosity monitors for the OLYMPUS experiment at DESY in Hamburg, Germany, with positron and electron beams at 2 GeV. The telescopes have been recycled to serve as the beam particle tracker of the MUSE experiment at the Paul Scherrer Institute in Switzerland. In the identical configuration as in OLYMPUS, the telescope was limiting the accepted trigger rate in the test measurements. Therefore, an effort is ongoing to improve the GEM readout speed to meet the trigger rate at the design intensity of the MUSE experiment. Further, the Hampton group is responsible for the DarkLight phase-I lepton tracker which is in preparation at the low energy-recovering facility (LERF) at the Thomas Jefferson National Accelerator Facility in Newport News, USA, sponsored by the National Science Foundation through a Major Research Instrumentation (MRI) grant. The group's activities on GEM detector development will be summarized, and the achieved performance and the current effort to further improvements will be discussed.

  14. Initial Tests of Commercially Manufactured Large GEM Foils and EIC Triple-GEM Detector Design

    NASA Astrophysics Data System (ADS)

    Kraishan, Amani

    2015-10-01

    Tracking detectors exist in many different varieties and operate on different physical principles, depending on the type of particle that has to be tracked, on the desired spatial resolution, and on the area that has to be covered. Gas electron multiplier (GEM) detectors, operating on the principle of electron amplification in gases, provide good spatial resolution for charged particles and can be built with large sensitive areas. Currently CERN is the only main distributor of large area GEM foils, and will be hard pressed to keep up with the increasing demand. To help satisfy the GEM foil demand, the commercialization of large area GEM foils via the single mask process has been established by Tech-Etch of Plymouth, MA, USA. Here we present our initial quality assurance tests of the foil's electrical and geometrical properties for sizes up to 40 X 40 cm2. Using our electrical and optical measurement setup, we also measured 10 X 10 cm2 GEMs produced by CERN and compare it with the Tech-Etch foils. Furthermore, we will present initial R&D design work done toward building a potential triple-GEM tracking detector to be used at a future experiment at an Electron-Ion Collider (EIC) facility.

  15. Study of Ion Back Flow suppression with thick COBRA GEM

    NASA Astrophysics Data System (ADS)

    Terasaki, K.

    2014-03-01

    Ion Back Flow (IBF) suppression is essential to avoid a space-charge distortion of the electric field under a high rate condition in the Time Projection Chamber (TPC). A GEM technology is one possible solution to achieve a small IBF and to keep a good performance in terms of particle tracking and particle identification at high rates in TPC. We developed Thick COBRA GEMs to investigate the capability of further IBF suppression. It was found that the COBRA GEM can suppress IBF more effectively compared to a standard GEM. IBF reaches about 0.1-0.5% with a stack configuration consisting of one standard GEM facing to the drift field and two COBRA GEMs. In this paper, the current status of development of COBRA GEM is described.

  16. Gravity model improvement using GEOS-3 (GEM 9 and 10)

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Klosko, S. M.; Laubscher, R. E.; Wagner, C. A.

    1977-01-01

    The use of collocation permitted GEM 9 to be a larger field than previous derived satellite models, GEM 9 having harmonics complete to 20 x 20 with selected higher degree terms. The satellite data set has approximately 840,000 observations, of which 200,000 are laser ranges taken on 9 satellites equipped with retroreflectors. GEM 10 is complete to 22 x 22 with selected higher degree terms out to degree and order 30 amounting to a total of 592 coefficients. Comparisons with surface gravity and altimeter data indicate a substantial improvement in GEM 9 over previous satellite solutions; GEM 9 is in even closer agreement with surface data than the previously published GEM 6 solution which contained surface gravity. In particular the free air gravity anomalies calculated from GEM 9 and a surface gravity solution are in excellent agreement for the high degree terms.

  17. Europa Imaging Highlights during GEM

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During the two year Galileo Europa Mission (GEM), NASA's Galileo spacecraft will focus intensively on Jupiter's intriguing moon, Europa. This montage shows samples of some of the features that will be imaged during eight successive orbits. The images in this montage are in order of increasing orbit from the upper left (orbit 11) to the lower right (orbit 19).

    DESCRIPTIONS AND APPROXIMATE RESOLUTIONSTriple bands and dark spots

    1.6 kilometers/pixelConamara Chaos

    1.6 kilometers/pixelMannan'an Crater

    1.6 kilometers/ pixelCilix

    1.6 kilometers/pixelAgenor Linea and Thrace Macula

    2 kilometers/pixelSouth polar terrain

    2 kilometers/pixelRhadamanthys Linea

    1.6 kilometers/pixelEuropa plume search

    7 kilometers/pixel

    1. Triple bands and dark spots were the focus of some images from Galileo's eleventh orbit of Jupiter. Triple bands are multiple ridges with dark deposits along the outer margins. Some extend for thousands of kilometers across Europa's icy surface. They are cracks in the ice sheet and indicate the great stresses imposed on Europa by tides raised by Jupiter, as well as Europa's neighboring moons, Ganymede and Io. The dark spots or 'lenticulae' are spots of localized disruption.

    2. The Conamara Chaos region reveals icy plates which have broken up, moved, and rafted into new positions. This terrain suggests that liquid water or ductile ice was present near the surface. On Galileo's twelfth orbit of Jupiter, sections of this region with resolutions as high as 10 meters per picture element will be obtained.

    3. Mannann'an Crater is a feature newly discovered by Galileo in June 1996. Color and high resolution images (to 40 meters per picture element) from Galileo's fourteenth orbit of Jupiter will offer a close look at the crater and help characterize how impacts affect the icy surface of this moon.

    4. Cilix, a large mound about 1.5 kilometers high, is the center of Europa's coordinate system. Its concave top and what may be flow

  18. Europa Imaging Highlights during GEM

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During the two year Galileo Europa Mission (GEM), NASA's Galileo spacecraft will focus intensively on Jupiter's intriguing moon, Europa. This montage shows samples of some of the features that will be imaged during eight successive orbits. The images in this montage are in order of increasing orbit from the upper left (orbit 11) to the lower right (orbit 19).

    DESCRIPTIONS AND APPROXIMATE RESOLUTIONSTriple bands and dark spots

    1.6 kilometers/pixelConamara Chaos

    1.6 kilometers/pixelMannan'an Crater

    1.6 kilometers/ pixelCilix

    1.6 kilometers/pixelAgenor Linea and Thrace Macula

    2 kilometers/pixelSouth polar terrain

    2 kilometers/pixelRhadamanthys Linea

    1.6 kilometers/pixelEuropa plume search

    7 kilometers/pixel

    1. Triple bands and dark spots were the focus of some images from Galileo's eleventh orbit of Jupiter. Triple bands are multiple ridges with dark deposits along the outer margins. Some extend for thousands of kilometers across Europa's icy surface. They are cracks in the ice sheet and indicate the great stresses imposed on Europa by tides raised by Jupiter, as well as Europa's neighboring moons, Ganymede and Io. The dark spots or 'lenticulae' are spots of localized disruption.

    2. The Conamara Chaos region reveals icy plates which have broken up, moved, and rafted into new positions. This terrain suggests that liquid water or ductile ice was present near the surface. On Galileo's twelfth orbit of Jupiter, sections of this region with resolutions as high as 10 meters per picture element will be obtained.

    3. Mannann'an Crater is a feature newly discovered by Galileo in June 1996. Color and high resolution images (to 40 meters per picture element) from Galileo's fourteenth orbit of Jupiter will offer a close look at the crater and help characterize how impacts affect the icy surface of this moon.

    4. Cilix, a large mound about 1.5 kilometers high, is the center of Europa's coordinate system. Its concave top and what may be flow

  19. Building the GEM Faulted Earth database

    NASA Astrophysics Data System (ADS)

    Litchfield, N. J.; Berryman, K. R.; Christophersen, A.; Thomas, R. F.; Wyss, B.; Tarter, J.; Pagani, M.; Stein, R. S.; Costa, C. H.; Sieh, K. E.

    2011-12-01

    The GEM Faulted Earth project is aiming to build a global active fault and seismic source database with a common set of strategies, standards, and formats, to be placed in the public domain. Faulted Earth is one of five hazard global components of the Global Earthquake Model (GEM) project. A key early phase of the GEM Faulted Earth project is to build a database which is flexible enough to capture existing and variable (e.g., from slow interplate faults to fast subduction interfaces) global data, and yet is not too onerous to enter new data from areas where existing databases are not available. The purpose of this talk is to give an update on progress building the GEM Faulted Earth database. The database design conceptually has two layers, (1) active faults and folds, and (2) fault sources, and automated processes are being defined to generate fault sources. These include the calculation of moment magnitude using a user-selected magnitude-length or magnitude-area scaling relation, and the calculation of recurrence interval from displacement divided by slip rate, where displacement is calculated from moment and moment magnitude. The fault-based earthquake sources defined by the Faulted Earth project will then be rationalised with those defined by the other GEM global components. A web based tool is being developed for entering individual faults and folds, and fault sources, and includes capture of additional information collected at individual sites, as well as descriptions of the data sources. GIS shapefiles of individual faults and folds, and fault sources will also be able to be uploaded. A data dictionary explaining the database design rationale, definitions of the attributes and formats, and a tool user guide is also being developed. Existing national databases will be uploaded outside of the fault compilation tool, through a process of mapping common attributes between the databases. Regional workshops are planned for compilation in areas where existing

  20. GAS eleven node thermal model (GEM)

    NASA Technical Reports Server (NTRS)

    Butler, Dan

    1988-01-01

    The Eleven Node Thermal Model (GEM) of the Get Away Special (GAS) container was originally developed based on the results of thermal tests of the GAS container. The model was then used in the thermal analysis and design of several NASA/GSFC GAS experiments, including the Flight Verification Payload, the Ultraviolet Experiment, and the Capillary Pumped Loop. The model description details the five cu ft container both with and without an insulated end cap. Mass specific heat values are also given so that transient analyses can be performed. A sample problem for each configuration is included as well so that GEM users can verify their computations. The model can be run on most personal computers with a thermal analyzer solution routine.

  1. X-Ray Polarimetry with GEMS

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod

    2011-01-01

    The polarization properties of cosmic X-ray sources are still largely unexplored. The Gravity and Extreme Magnetism SMEX (GEMS) will carry out the first sensitive X-ray polarization survey of a wide range of sources including; accreting compact objects (black holes and neutron stars), AGN, supernova remnants, magnetars and rotation-powered pulsars. GEMS employs grazing-incidence foil mirrors and novel time-projection chamber (TPC) polarimeters leveraging the photoelectric effect to achieve high polarization sensitivity in the 2 - 10 keV band. I will provide an update of the project status, illustrate the expected performance with several science examples, and provide a brief overview of the data analysis challenges

  2. Gallium Electromagnetic (GEM) Thrustor Concept and Design

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Markusic, Thomas E.

    2006-01-01

    We describe the design of a new type of two-stage pulsed electromagnetic accelerator, the gallium electromagnetic (GEM) thruster. A schematic illustration of the GEM thruster concept is given in Fig. 1. In this concept, liquid gallium propellant is pumped into the first stage through a porous metal electrode using an electromagneticpump[l]. At a designated time, a pulsed discharge (approx.10-50 J) is initiated in the first stage, ablating the liquid gallium from the porous electrode surface and ejecting a dense thermal gallium plasma into the second state. The presence of the gallium plasma in the second stage serves to trigger the high-energy (approx.500 I), send-stage puke which provides the primary electromagnetic (j x B) acceleration.

  3. GEM Workshop on Intercalibrating Cusp Signatures

    NASA Astrophysics Data System (ADS)

    On October 9, 1990, a lively group of more than 60 scientists from around the world gathered at Northeastern University's Henderson House in Weston, Mass., to spend 4 days in concentrated efforts to unravel the complexities of cusp/cleft theory and observations.Plans for the National Science Foundation-sponsored workshop were formulated at the previous GEM workshop convened by Ted Rosenberg at the University of Maryland in October 1989, where participants agreed that the first task of the first GEM campaign—attacking problems of the magnetopause, boundary layers, and their signatures in the ionosphere—should be the identification of cusp signatures in ground-based and airborne data by intercalibrating with spacecraft data on direct overflights.

  4. Galium Electromagnetic (GEM) Thruster Concept and Design

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Markusic, Thomas E.

    2005-01-01

    We describe the design of a new type of two-stage pulsed electromagnetic accelerator, the gallium electromagnetic (GEM) thruster. A schematic illustration of the GEM thruster concept is given. In this concept, liquid gallium propellant is pumped into the first stage through a porous metal electrode using an electromagnetic pump. At a designated time, a pulsed discharge (approx. 10-50 J) is initiated in the first stage, ablating the liquid gallium from the porous electrode surface and ejecting a dense thermal gallium plasma into the second state. The presence of the gallium plasma in the second stage serves to trigger the high-energy (approx. 500 J), second-stage pulse which provides the primary electromagnetic (j x B) acceleration.

  5. Nebraska NativeGEM (Geospatial Extension Model)

    NASA Technical Reports Server (NTRS)

    Bowen, Brent

    2004-01-01

    This proposal, Nebraska NativeGEM (Geospatial Extension Model) features a unique diversity component stemming from the exceptional reputation NNSGC has built by delivering geospatial science experiences to Nebraska s Native Americans. For 7 years, NNSGC has partner4 with the 2 tribal colleges and 4 reservation school districts in Nebraska to form the Nebraska Native American Outreach Program (NNAOP), a partnership among tribal community leaders, academia, tribal schools, and industry reaching close to 1,OOO Native American youth, over 1,200 community members (Lehrer & Zendajas, 2001).NativeGEM addresses all three key components of Cooperative State Research, Education, and Extension Service (CSREES) goals for advancing decision support, education, and workforce development through the GES. The existing long term commitments that the NNSGC and the GES have in these areas allow for the pursuit of a broad range of activities. NativeGEM builds upon these existing successful programs and collaborations. Outcomes and metrics for each proposed project are detailed in the Approach section of this document.

  6. FSelector: a Ruby gem for feature selection

    PubMed Central

    Wang, Yanli; Bryant, Stephen H.

    2012-01-01

    Summary: The FSelector package contains a comprehensive list of feature selection algorithms for supporting bioinformatics and machine learning research. FSelector primarily collects and implements the filter type of feature selection techniques, which are computationally efficient for mining large datasets. In particular, FSelector allows ensemble feature selection that takes advantage of multiple feature selection algorithms to yield more robust results. FSelector also provides many useful auxiliary tools, including normalization, discretization and missing data imputation. Availability: FSelector, written in the Ruby programming language, is free and open-source software that runs on all Ruby supporting platforms, including Windows, Linux and Mac OS X. FSelector is available from https://rubygems.org/gems/fselector and can be installed like a breeze via the command gem install fselector. The source code is available (https://github.com/need47/fselector) and is fully documented (http://rubydoc.info/gems/fselector/frames). Contact: ywang@ncbi.nlm.nih.gov or bryant@ncbi.nlm.nih.gov Supplementary Information: Supplementary data are available at Bioinformatics online. PMID:22942017

  7. Comparative verification between GEM model and official aviation terminal forecasts

    NASA Technical Reports Server (NTRS)

    Miller, Robert G.

    1988-01-01

    The Generalized Exponential Markov (GEM) model uses the local standard airways observation (SAO) to predict hour-by-hour the following elements: temperature, pressure, dew point depression, first and second cloud-layer height and amount, ceiling, total cloud amount, visibility, wind, and present weather conditions. GEM is superior to persistence at all projections for all elements in a large independent sample. A minute-by-minute GEM forecasting system utilizing the Automated Weather Observation System (AWOS) is under development.

  8. Optical and electrical performance of commercially manufactured large GEM foils

    NASA Astrophysics Data System (ADS)

    Posik, M.; Surrow, B.

    2015-12-01

    With interest in large area GEM foils increasing and CERN being the only main distributor, keeping up with the demand for GEM foils will be difficult. Thus the commercialization of GEMs is being established by Tech-Etch of Plymouth, MA, USA using single-mask techniques. We report here on the first of a two step quality verification of the commercially produced 10×10 cm2 and 40×40 cm2 GEM foils, which includes characterizing their electrical and geometrical properties. We have found that the Tech-Etch foils display excellent electrical properties, as well as uniform and consistent hole diameters comparable to established foils produced by CERN.

  9. GEM Building Taxonomy (Version 2.0)

    USGS Publications Warehouse

    Brzev, S.; Scawthorn, C.; Charleson, A.W.; Allen, L.; Greene, M.; Jaiswal, Kishor; Silva, V.

    2013-01-01

    /7/8/IRRE9/10/RSH3+RWO211/FW12/13/ which can be read as (1) Direction = [DX or DY] (the building has the same lateral load-resisting system in both directions); (2) Material = [Unreinforced Masonry + solid fired clay bricks + cement: lime mortar]; (3) Lateral Load-Resisting System = [Wall]; (4) Date of construction = [pre-1939]; (5) Heaight = [exactly 2 storeys]; (6) Occupancy = [residential, unknown type]; (7) Building Position = [unknown = no entry]; (8) Shape of building plan = [unknown = no entry]; (9) Structural irregularity = [regular]; (10) Exterior walls = [unknown = no entry]; (11) Roof = [Shape: pitched and hipped, Roof covering: clay tiles, Roof system material: wood, Roof system type: wood trusses]; (12) Floor = [Floor system: Wood, unknown]; (13) Foundation = [unknown = no entry]. Mapping of GEM Building Taxonomy to selected taxonomies is included in the report -- for example, the above building would be referenced by previous structural taxonomies as: PAGER-STR as UFB or UFB4, by the World Housing Encyclopedia as 7 or 8 and by the European Macroseismic Scale (98) as M5. The Building Taxonomy data model is highly flexible and has been incorporated within a relational database architecture. Due to its ability to represent building typologies using a shorthand form, it is also possible to use the taxonomy for non-database applications, and we discuss possible application of adaptation for Building Information Modelling (BIM) systems, and for the insurance industry. The GEM Building Taxonomy was independently evaluated and tested by the Earthquake Engineering Research Institute (EERI), which received 217 TaxT reports from 49 countries, representing a wide range of building typologies, including single and multi-storey buildings, reinforced and unreinforced masonry, confined masonry, concrete, steel, wood, and earthern buildings used for residential, commercial, industrial, and educational occupancy. Based on these submissions and other feedback, the EERI

  10. GEMS at the galactic cosmic-ray source.

    SciTech Connect

    Westphal, A. J.; Davis, A. M.; Levine, J.; Pellin, M. J.; Savina, M. R.

    2007-01-01

    Galactic cosmic rays probably predominantly originate from shock-accelerated gas and dust in superbubbles. It is usually assumed that the shock-accelerated dust is quickly destroyed by sputtering. However, it may be that some of the dust can survive bombardment by the high-metallicity gas in the superbubble interior, and that some of that dust has been incorporated into solar system materials. Interplanetary dust particles (IDPs) contain enigmatic submicron components called GEMS (Glass with Embedded Metal and Sulfides). These GEMS have properties that closely match those expected of a population of surviving shock-accelerated dust at the GCR source (Westphal and Bradley in Astrophys. J. 617:1131, 2004). In order to test the hypothesis that GEMS are synthesized from shock-accelerated dust in superbubbles, we plan to measure the relative abundances of Fe, Zr, and Mo isotopes in GEMS using the new Resonance Ionization Mass Spectrometer at Argonne National Laboratory. If GEMS are synthesized from shock-accelerated dust in superbubbles, they should exhibit isotopic anomalies in Fe, Zr and Mo: specificially, enhancements in the r-only isotopes {sup 96}Zr and {sup 100}Mo, and separately in {sup 58}Fe, should be observed. We review also recent developments in observations of GEMS, laboratory synthesis of GEMS-like materials, and implications of observations of GEMS-like materials in Stardust samples.

  11. PROGRAM COORDINATION FOR THE GULF ECOLOGICAL MANAGMENT SITES (GEMS) PROGRAM

    EPA Science Inventory

    The Gulf Ecological Management Site (GEMS) Program is an initiative of the Gulf of Mexico Program (GMP) and the five Gulf of Mexico states. It provides a regional framework for focusing attention on ecologically important Gulf habitats. The GEMS Program coordinates and utilizes ...

  12. The Grief Evaluation Measure (GEM): An Initial Validation Study

    ERIC Educational Resources Information Center

    Jordan, John R.; Baker, John; Matteis, Margherite; Rosenthal, Saul; Ware, Eugenia S.

    2005-01-01

    This article describes the development of the Grief Evaluation Measure (GEM), a new instrument designed to screen for the development of a complicated mourning response in a bereaved adult. The GEM provides a quantitative and qualitative assessment of risk factors, including the mourner's loss and medical history, coping resources before and after…

  13. Network Information Discovery and Retrieval of Educational Materials: GEM.

    ERIC Educational Resources Information Center

    Sutton, Stuart A.

    2000-01-01

    Describes the GEM (Gateway to Educational Materials) project that was developed to provide retrieval of lesson plans and teacher guides on the Internet . Discusses the development of a metadata set for controlled description based on the Dublin Core, distributing GEM metadata on the World Wide Web, and future…

  14. Diffraction measurements with a boron-based GEM neutron detector

    NASA Astrophysics Data System (ADS)

    Croci, Gabriele; Albani, Giorgia; Cazzaniga, Carlo; Perelli Cippo, Enrico; Schooneveld, Erik; Claps, Gerardo; Cremona, Anna; Grosso, Giovanni; Muraro, Andrea; Murtas, Fabrizio; Rebai, Marica; Scherillo, Antonella; Tardocchi, Marco; Gorini, Giuseppe

    2014-07-01

    The research of reliable substitutes of 3He detectors is an important task for the affordability of new neutron scattering instrumentation for future spallation sources like the European Spallation Source. GEM (Gas Electron Multiplier)-based detectors represent a valid alternative since they can combine high-rate capability, coverage of up to 1\\ \\text{m}^{2} area and good intrinsic spatial resolution (for this detector class it can be better than 0.5 mm). The first neutron diffraction measurements performed using a borated GEM detector are reported. The detector has an active area of 10 \\times 5\\ \\text{cm}^{2} and is equipped with a borated cathode. The GEM detector was read out using the standard ISIS Data Acquisition System. The comparison with measurements performed with standard 3He detectors shows that the broadening of the peaks measured on the diffractogram obtained with the GEM is 20-30% wider than the one obtained by 3He tubes but the active area of the GEM is twice that of 3He tubes. The GEM resolution is improved if half of its active area is considered. The signal-to-background ratio of the GEM is about 1.5 to 2 times lower than that of 3He. This measurement proves that GEM detectors can be used for neutron diffraction measurements and paves the way for their use at future neutron spallation sources.

  15. The Ozone Layer. UNEP/GEMS Environment Library No. 2.

    ERIC Educational Resources Information Center

    United Nations Environment Programme, Nairobi (Kenya).

    Since the United Nations Environment Program (UNEP) was created, more than a dozen years ago, public understanding of the environmental issues confronting our planet has increased enormously. The Global Environment Monitoring System (GEMS) has provided several environmental assessments. The aim of the UNEP/GEMS Environment Library is to provide…

  16. Guidance Exploration Model (GEM) 1978-79. Summary.

    ERIC Educational Resources Information Center

    Pope, M. Candice, Comp.

    The original program goal for development was to provide implementation of a Guidance Exploratory Model (GEM) at the elementary level which combines career education, guidance, exploration and academics. During the planning stages of GEM, monies were received from Title IV-B to purchase books and audio-visual materials to initiate the concept…

  17. MIT-CSR XIS Project

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This report outlines the proposers' progress toward MIT's contribution to the X-Ray Imaging Spectrometer (XIS) experiment on the Japanese ASTRO-E mission. The report discusses electrical system design, mechanical system design, and ground support equipment.

  18. MIT research in telerobotics

    NASA Technical Reports Server (NTRS)

    Sheridan, T. B.

    1987-01-01

    Ongoing MIT research in telerobotics (vehicles capable of some autonomous sensing and manipulating, having some remote supervisory control by people) and teleoperation (vehicles for sensing and manipulating which are fully controlled remotely by people) is discussed. The current efforts mix human and artificial intelligence/control. The idea of adjustable impedance at either end of pure master-slave teleoperation, and simultaneous coordinated control of teleoperator/telerobotic systems which have more than six degrees of freedom (e.g., a combined vehicle and arm, each with five or six DOF) are discussed. A new cable-controlled parallel link arm which offers many advantages over conventional arms for space is briefly described. Predictor displays to compensate for time delay in teleoperator loops, the use of state estimation to help human control decisions in space, and ongoing research in supervisory command language are covered. Finally, efforts to build a human flyable real-time dynamic computer-graphic telerobot simulator are described. These projects represent most, but not all, of the telerobotics research in our laboratory, supported by JPL, NASA Ames and NOAA.

  19. GEMS X-ray Polarimeter Performance Simulations

    NASA Technical Reports Server (NTRS)

    Baumgartner, Wayne H.; Strohmayer, Tod; Kallman, Tim; Black, J. Kevin; Hill, Joanne; Swank, Jean

    2012-01-01

    The Gravity and Extreme Magnetism Small explorer (GEMS) is an X-ray polarization telescope selected as a NASA small explorer satellite mission. The X-ray Polarimeter on GEMS uses a Time Projection Chamber gas proportional counter to measure the polarization of astrophysical X-rays in the 2-10 keV band by sensing the direction of the track of the primary photoelectron excited by the incident X-ray. We have simulated the expected sensitivity of the polarimeter to polarized X-rays. We use the simulation package Penelope to model the physics of the interaction of the initial photoelectron with the detector gas and to determine the distribution of charge deposited in the detector volume. We then model the charge diffusion in the detector,and produce simulated track images. Within the track reconstruction algorithm we apply cuts on the track shape and focus on the initial photoelectron direction in order to maximize the overall sensitivity of the instrument, using this technique we have predicted instrument modulation factors nu(sub 100) for 100% polarized X-rays ranging from 10% to over 60% across the 2-10 keV X-ray band. We also discuss the simulation program used to develop and model some of the algorithms used for triggering, and energy measurement of events in the polarimeter.

  20. Extending the ISC-GEM Global Earthquake Instrumental Catalogue

    NASA Astrophysics Data System (ADS)

    Di Giacomo, Domenico; Engdhal, Bob; Storchak, Dmitry; Villaseñor, Antonio; Harris, James

    2015-04-01

    After a 27-month project funded by the GEM Foundation (www.globalquakemodel.org), in January 2013 we released the ISC-GEM Global Instrumental Earthquake Catalogue (1900 2009) (www.isc.ac.uk/iscgem/index.php) as a special product to use for seismic hazard studies. The new catalogue was necessary as improved seismic hazard studies necessitate that earthquake catalogues are homogeneous (to the largest extent possible) over time in their fundamental parameters, such as location and magnitude. Due to time and resource limitation, the ISC-GEM catalogue (1900-2009) included earthquakes selected according to the following time-variable cut-off magnitudes: Ms=7.5 for earthquakes occurring before 1918; Ms=6.25 between 1918 and 1963; and Ms=5.5 from 1964 onwards. Because of the importance of having a reliable seismic input for seismic hazard studies, funding from GEM and two commercial companies in the US and UK allowed us to start working on the extension of the ISC-GEM catalogue both for earthquakes that occurred beyond 2009 and for earthquakes listed in the International Seismological Summary (ISS) which fell below the cut-off magnitude of 6.25. This extension is part of a four-year program that aims at including in the ISC-GEM catalogue large global earthquakes that occurred before the beginning of the ISC Bulletin in 1964. In this contribution we present the updated ISC GEM catalogue, which will include over 1000 more earthquakes that occurred in 2010 2011 and several hundreds more between 1950 and 1959. The catalogue extension between 1935 and 1949 is currently underway. The extension of the ISC-GEM catalogue will also be helpful for regional cross border seismic hazard studies as the ISC-GEM catalogue should be used as basis for cross-checking the consistency in location and magnitude of those earthquakes listed both in the ISC GEM global catalogue and regional catalogues.

  1. The gated electrostatic mass spectrometer (GEMS): definition and preliminary results.

    PubMed

    Herrero, Federico A; Jones, Hollis H; Lee, Jeffrey G

    2008-10-01

    GEMS is a new type of time-of-flight mass spectrometer based on an electrostatic energy analyzer. Mass resolution equals the energy analyzer kinetic energy resolution, which is set by its slit size. In GEMS, monochromatic ions enter the entrance slit at random times, and the gated ion deflection produced by the electrostatic field in the analyzer rejects ions that are inside the analyzer at gate onset, detecting those entering the analyzer after gate onset. This provides mass separation while overcoming the temporal and spatial spread problems typical of TOF applications. Paradoxically, GEMS works because all ion masses follow identical trajectories. GEMS is easily multiplied into two-dimensional arrays to increase sensitivity in space applications, requires relatively low voltages, and uses only a few electrical connections. Thus, it is easy to package GEMS as a small, low-power instrument for applications in harsh environments. A disadvantage of GEMS is that its output is the integral of the TOF spectrum and the derivative of the raw data must be taken, a procedure that is likely to add noise. A version of GEMS detecting un-deflected ions (u-GEMS) has been tested to demonstrate the time-integrated feature of the raw data but without the benefit of energy analysis. This paper describes GEMS implemented with the small deflection energy analyzer (SDEA), a compact version of the parallel plate energy analyzer. SDEA is described both analytically and with ion trajectory simulations using the ion trajectory simulation software SIMION; the results are then used to describe GEMS and compute its performance. PMID:18718764

  2. Heavy metals in Ratnapura alluvial gem sediments, Sri Lanka

    NASA Astrophysics Data System (ADS)

    Vithanage, M. S.; Hettiarachchi, J. K.; Rajapaksha, A. U.; Wijesekara, H.; Hewawasam, T.

    2011-12-01

    The valuable gems in Sri Lanka are found from the sedimentary gem deposits in Ratnapura District, which are found as alluvial deposits some are about >50 m deep. Gem bearing gravel layer is taken out from the mine, washed by panning to recover the gem minerals in the heavy mineral fraction, is a common practice in the gem mining area. Gem bearing sediment layer is associated with different heavy minerals in which different trace metals as Co, Cr, Cu, Al, Zr, Pb and As also can be present. During panning, the sediment is washed away and the heavy metals attached to the sediments are released into the environment. Hence we studied the lability and bioavailability of arsenic and other heavy metals from the gem sediments. Sediment samples were collected from 15 small scale gem mines (3 soil layers- top, gem mineral layer and layer below gem bearing gravel layer), air dried and sieved to obtain <63μm fraction. Bioavailable, exchangeable and residual fractions were 0.01M CaCl2, 1M NaOAc, pH 8.2 and microwave digestion using HF, HNO3 and HClO4. Filtered samples were analyzed for As, Co, Zn, Mn, Cu, Ni, Pb and Fe using atomic absorption spectrophotometer (GBC 933AA). Total digestion results in different layers indicated that heavy metals show an increasing pattern with depth. About 4 gem bearing gravel layers were consist of high concentrations of Ni (>150 mg/kg), Cu (>150 mg/kg), Pb (>400 mg/kg), Zn (>600 mg/kg) and Co ions (>100 mg/kg). Arsenite in the gem sediments were low and recorded as <5mg/kg. Total arsenic analysis is under investigation. Highest concentrations for bioavailable and exchangeable (leach to water) metals were Fe>Co>Zn>Mn>Ni>Cu>Pb. Sediments from few gem pits showed considerably high concentrations of metals analyzed. In some places Fe, Ni, Cu, Zn reported high in bioavailable fractions 70, 25, 20, 10 mg/kg respectively. Mobilization of these metals may increase due to changes in the pH and the presence of other ions in the environment. High

  3. MIT's interferometer CST testbed

    NASA Technical Reports Server (NTRS)

    Hyde, Tupper; Kim, ED; Anderson, Eric; Blackwood, Gary; Lublin, Leonard

    1990-01-01

    The MIT Space Engineering Research Center (SERC) has developed a controlled structures technology (CST) testbed based on one design for a space-based optical interferometer. The role of the testbed is to provide a versatile platform for experimental investigation and discovery of CST approaches. In particular, it will serve as the focus for experimental verification of CSI methodologies and control strategies at SERC. The testbed program has an emphasis on experimental CST--incorporating a broad suite of actuators and sensors, active struts, system identification, passive damping, active mirror mounts, and precision component characterization. The SERC testbed represents a one-tenth scaled version of an optical interferometer concept based on an inherently rigid tetrahedral configuration with collecting apertures on one face. The testbed consists of six 3.5 meter long truss legs joined at four vertices and is suspended with attachment points at three vertices. Each aluminum leg has a 0.2 m by 0.2 m by 0.25 m triangular cross-section. The structure has a first flexible mode at 31 Hz and has over 50 global modes below 200 Hz. The stiff tetrahedral design differs from similar testbeds (such as the JPL Phase B) in that the structural topology is closed. The tetrahedral design minimizes structural deflections at the vertices (site of optical components for maximum baseline) resulting in reduced stroke requirements for isolation and pointing of optics. Typical total light path length stability goals are on the order of lambda/20, with a wavelength of light, lambda, of roughly 500 nanometers. It is expected that active structural control will be necessary to achieve this goal in the presence of disturbances.

  4. GEM-based detectors for thermal and fast neutrons

    NASA Astrophysics Data System (ADS)

    Croci, G.; Claps, G.; Cazzaniga, C.; Foggetta, L.; Muraro, A.; Valente, P.

    2015-06-01

    Lately the problem of 3He replacement for neutron detection stimulated an intense activity research on alternative technologies based on alternative neutron converters. This paper presents briefly the results obtained with new GEM detectors optimized for fast and thermal neutrons. For thermal neutrons, we realized a side-on GEM detector based on a series of boron-coated alumina sheets placed perpendicularly to the incident neutron beam direction. This prototype has been tested at n@BTF photo-production neutron facilty in order to test its effectiveness under a very high flux gamma background. For fast neutrons, we developed new GEM detectors (called nGEM) for the CNESM diagnostic system of the SPIDER NBI prototype for ITER (RFX-Consortium, Italy) and as beam monitor for fast neutrons lines at spallation sources. The nGEM is a Triple GEM gaseous detector equipped with a polyethylene layer used to convert fast neutrons into recoil protons through the elastic scattering process. This paper describes the results obtained by testing a medium size (30 × 25 cm2 active area) nGEM detector at the ISIS spallation source on the VESUVIO beam line.

  5. Complete Tem-Tomography: 3D Structure of Gems Cluster

    NASA Technical Reports Server (NTRS)

    Matsuno, J.; Miyake, A.; Tsuchiyama, A.; Messenger, S.; Nakamura-Messenger, K.

    2015-01-01

    GEMS (glass with embedded metal and sulfide) grains in interplanetary dust particles (IDPs) are considered to be one of the ubiquitous and fundamental building blocks of solids in the Solar System. They have been considered to be interstellar silicate dust that survived various metamorphism or alteration processes in the protoplanetary disk but the elemental and isotopic composition measurements suggest that most of them have been formed in the protoplanetary disk as condensates from high temperature gas. This formation model is also supported by the formation of GEMS-like grains with respect to the size, mineral assemblage, texture and infrared spectrum by condensation experiments from mean GEMS composition materials. Previous GEMS studies were performed only with 2D observation by transmission electron microscopy (TEM) or scanning TEM (STEM). However, the 3D shape and structure of GEMS grains and the spatial distribution of Fe/FeS's has critical information about their formation and origin. Recently, the 3D structure of GEMS grains in ultrathin sections of cluster IDPs was revealed by electron tomography using a TEM/STEM (JEM-2100F, JEOL). However, CT images of thin sections mounted on Cu grids acquired by conventional TEM-tomography are limited to low tilt angles (e. g., less than absolute value of 75 deg. In fact, previous 3D TEM observations of GEMS were affected by some artifacts related to the limited tilt range in the TEM used. Complete tomographic images should be acquired by rotating the sample tilt angle over a range of more than absolute value of 80 deg otherwise the CT images lose their correct structures. In order to constrain the origin and formation process of GEMS grains more clearly, we performed complete electron tomography for GEMS grains. Here we report the sample preparation method we have developed for this study, and the preliminary results.

  6. Method and apparatus for detecting gem-polyhalogenated hydrocarbons

    DOEpatents

    Anderson, deceased, William G.; Anderson, legal representative, Johanna S.

    1990-01-01

    A method and optrode for detecting gem polyhalogenated hydrocarbons in a sample fluid based on a single phase Fujiwara reaction as provided. The method comprises contacting a reaction mixture with a sample fluid which contains the gem-polyhalogenated hydrocarbons. The reaction mixture comprises an aqueous solution of pyridine or derivative thereof and a hindered nitrogen base. Upon contact a fluorescent and/or chromgenic reaction product forms whose fluorescence and/or absorbance is related to the concentration of gem-polyhalogenated hydrocarbons in the sample fluid.

  7. Image examination of comet Hale-Bopp and α Gem.

    NASA Astrophysics Data System (ADS)

    Li, Qiusha; Zhang, Bairong; Wang, Feng

    A new Astronomy Video Image Acquisition System (AVIAS) is used in the image processing of comet Hale-Bopp and α Gem which were recorded by a video camera (Panasonic-NV-S880EN) on May 1, 1997. It is shown that the details of multi-integration images for comet Hale-Bopp and α Gem are more distinct than that of single image. The faint star near α Gem cannot be found in the single frame image but can be recognized in the multi-integration image.

  8. MIT Space Engineering Research Center

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Miller, David W.

    1990-01-01

    The Space Engineering Research Center (SERC) at MIT, started in Jul. 1988, has completed two years of research. The Center is approaching the operational phase of its first testbed, is midway through the construction of a second testbed, and is in the design phase of a third. We presently have seven participating faculty, four participating staff members, ten graduate students, and numerous undergraduates. This report reviews the testbed programs, individual graduate research, other SERC activities not funded by the Center, interaction with non-MIT organizations, and SERC milestones. Published papers made possible by SERC funding are included at the end of the report.

  9. The GEM (Gravity-Electro-Magnetism) Theory of Field Unification and its Application to Human Flight and Gravity Wave Production and Detection

    NASA Astrophysics Data System (ADS)

    Brandenburg, J. E.

    2005-02-01

    Theoretical progress on the GEM (Gravity-Electro-Magnetism) unification theory is summarized as applied to human flight and dynamically modified gravity fields and waves, as well as progress towards a GEMS (GEMStrong) theory. The GEM theory in the static Newtonian limit is the portion of the Kaluza-Klein action that is quadratic in first derivatives of the metric and in Poynting Flux that appears in the form of a VBE ("Vacuum Bernoulli Equation"). This shows Gravitational energy density to be equated to an EM dynamic pressure that is quadratic in the local Poynting Flux: g2/(2π G) + S2/(c2 L)= Constant, where g and S are the local gravity and Poynting vector magnitudes, respectively, and where L is the Lagrangian density of the vacuum EM field. The VBE can be used to understand anomalous weight loss reported in gyroscope experiments and to understand possible gravity modification for human flight. The GEM gravity modification theory is extended to predict a VHE (Vacuum Hall Effect). Methods for creating dynamic gravity fields via VHE for production and detection of high frequency gravity fields involve electric quadrapole fields normal to static magnetic fields. In terms of fundamental GEM theory, the important value of the proton to electron mass ratio Rm =1836 in the theory is linked, via the MIT Bag Model, to the value of the reciprocal fine structure constant: Rm=αs/α where αs =13.34 is the asymptotic Strong Force coupling constant. An experiment was performed using this theory that validated the anomalous gyroscope effects predicted by Kosyrev and others, that rotating EM fields appear to create lifting forces. The theory appears to offer insights into enhanced forms of propellant-less propulsion.

  10. Gem and Mineral Shows as Geologic Teaching Opportunities.

    ERIC Educational Resources Information Center

    Cordua, William Sinclair

    1988-01-01

    Gem and mineral shows are excellent nontraditional opportunities for community education and outreach by geology teachers. Discusses initial club contacts, displays, shows, and the advantages of show participation to academic geologists. (CW)

  11. A gravity model for crustal dynamics (GEM-L2)

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Klosko, S. M.; Patel, G. B.; Wagner, C. A.

    1985-01-01

    The Laser Geodynamics Satellite (Lageos) was the first NASA satellite which was placed into orbit exclusively for laser ranging applications. Lageos was designed to permit extremely accurate measurements of the earth's rotation and the movement of the tectonic plates. The Goddard earth model, GEM-L2, was derived mainly on the basis of the precise laser ranging data taken on many satellites. Douglas et al. (1984) have demonstrated the utility of GEM-L2 in detecting the broadest ocean circulations. As Lageos data constitute the most extensive set of satellite laser observations ever collected, the incorporation of 2-1/2 years of these data into the Goddard earth models (GEM) has substantially advanced the geodynamical objectives. The present paper discusses the products of the GEM-L2 solution.

  12. GEMS Revealed: Spectrum Imaging of Aggregate Grains in Interplanetary Dust

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Messenger, S.; Christoffersen, R.

    2005-01-01

    Anhydrous interplanetary dust particles (IDPs) of cometary origin contain abundant materials that formed in the early solar nebula. These materials were transported outward and subsequently mixed with molecular cloud materials and presolar grains in the region where comets accreted [1]. GEMS (glass with embedded metal and sulfides) grains are a major component of these primitive anhydrous IDPs, along with crystalline Mg-rich silicates, Fe-Ni sulfides, carbonaceous material, and other trace phases. Some GEMS grains (5%) are demonstrably presolar based on their oxygen isotopic compositions [2]. However, most GEMS grains are isotopically solar and have bulk chemical compositions that are incompatible with inferred compositions of interstellar dust, suggesting a solar system origin [3]. An alternative hypothesis is that GEMS grains represent highly irradiated interstellar grains whose oxygen isotopic compositions were homogenized through processing in the interstellar medium (ISM) [4]. We have obtained the first quantitative X-ray maps (spectrum images) showing the distribution of major and minor elements in individual GEMS grains. Nanometer-scale chemical maps provide critical data required to evaluate the differing models regarding the origin of GEMS grains.

  13. SSC analysis of the GEMs for reactivity control in PRISM

    SciTech Connect

    Slovik, G.C.; Rodnizki, J.

    1992-01-01

    The performance of three Gas Expansion Modules (GEMS) utilized the Advanced Liquid Metal Reactor (ALMR) concept, PRISM, was analyzed using the computer code, SSC. GE has submitted the PRISM design for a Preapplication Safety Evaluation Report (PSER). The draft PSER indicated a potential weakness in the Unscrammed Loss of Flow (ULOF) event, and GE modified the design by adding three GEMs. The PRISM design was analyzed by SSC for two cases. First, the design's original response to a ULOF where one Electro Magnetic (EM) pump fails to produce a coastdown was analyzed. Then the revised design with the GEMs included was analyzed. The original design had little or no safety margin for this case. The peak fuel temperature in the hot channel was predicted to be 1358K, which is above the solidus temperature of the fuel. However, after the GEMs were added, the loss of one EM pump coastdown became a benign event. The GEM feedback was predicted by SSC to dominate the other reactivity feedbacks and the GEMS, essentially, responded like passive control rods. The fuel temperature quickly dropped below operating temperatures, while the margin to sodium boiling was predicted to be greater than 350K.

  14. SSC analysis of the GEMs for reactivity control in PRISM

    SciTech Connect

    Slovik, G.C.; Rodnizki, J.

    1992-12-31

    The performance of three Gas Expansion Modules (GEMS) utilized the Advanced Liquid Metal Reactor (ALMR) concept, PRISM, was analyzed using the computer code, SSC. GE has submitted the PRISM design for a Preapplication Safety Evaluation Report (PSER). The draft PSER indicated a potential weakness in the Unscrammed Loss of Flow (ULOF) event, and GE modified the design by adding three GEMs. The PRISM design was analyzed by SSC for two cases. First, the design`s original response to a ULOF where one Electro Magnetic (EM) pump fails to produce a coastdown was analyzed. Then the revised design with the GEMs included was analyzed. The original design had little or no safety margin for this case. The peak fuel temperature in the hot channel was predicted to be 1358K, which is above the solidus temperature of the fuel. However, after the GEMs were added, the loss of one EM pump coastdown became a benign event. The GEM feedback was predicted by SSC to dominate the other reactivity feedbacks and the GEMS, essentially, responded like passive control rods. The fuel temperature quickly dropped below operating temperatures, while the margin to sodium boiling was predicted to be greater than 350K.

  15. GEM Detectors for Muon Tomography of Nuclear Contraband

    NASA Astrophysics Data System (ADS)

    Quintero, Amilkar; Gnanvo, Kondo; Grasso, Leonard; Locke, Judson; Mitra, Debasis; Hohlmann, Marcus

    2010-02-01

    The construction of a Muon Tomography station is presented. Muon Tomography (MT), based on scattering of cosmic ray muons, is an improvement to actual portal monitors at borders, since the current techniques use regular radiation detection that are not very sensitive to nuclear contraband (U, Pu), if these materials are well shielded to absorb emanating radiation. We use a low mass, high spatial resolution (˜50 μm) Gas Electron Multiplier (GEM) detectors for MT to overcome the intrinsic limitations. The prototype MT station employs 6 tracking stations based on 33cm x 33cm triple-GEM detectors with 2D readout. The detectors are arranged into tracking superlayers at the top and bottom of the probed volume. Due to the excellent spatial resolution of GEM, it is sufficient to use few cm gap between tracking stations. We present details of the production and assembly of the GEM-based tracking stations in collaboration with CERN-GDD lab and RD51 experiment as well as the design of the corresponding front-end electronics and readout system. Discussion about GEM detectors in two sides of the probed volume for a complete muon tracking, and large-area (1m x 1m) GEM-based MT station prototype to be tested under realistic conditions, are made. )

  16. Measurement Of Gas Electron Multiplier (GEM) Detector Characteristics

    NASA Astrophysics Data System (ADS)

    Park, Seongtae; Baldelomar, Edwin; Park, Kwangjune; Sosebee, Mark; White, Andy; Yu, Jaehoon

    2011-06-01

    The High Energy Physics group of the University of Texas at Arlington has been developing gas electron multiplier detectors to use them as sensitive gap detectors in digital hadron calorimeters for the International Linear Collider, a future high energy particle accelerator. For this purpose, we constructed numerous GEM detectors that employ double GEM layers. In this study, two kinds of prototype GEM detectors were tested; one with 28×28 cm2 active area double GEM structure with a 3 mm drift gap, a 1 mm transfer gap and a 1 mm induction gap and the other with two 3×3 cm2 GEM foils in the amplifier stage with a 5 mm drift gap, a 2 mm transfer gap and a 1 mm induction gap. The detectors' characteristics from exposure to high-energy charged particles and other radiations were measured using cosmic rays and 55Fe radioactive source. From the 55Fe tests, we observed two well separated characteristic X-ray emission peaks and confirmed the detectors' functionality. We also measured chamber gains to be over 6000 at a high voltage of 395 V across each GEM electrode. The responses to cosmic rays show the spectra that fit well to Landau distributions as expected from minimum ionizing particles.

  17. Measurement Of Gas Electron Multiplier (GEM) Detector Characteristics

    SciTech Connect

    Park, Seongtae; Baldelomar, Edwin; Sosebee, Mark; White, Andy; Yu, Jaehoon; Park, Kwangjune

    2011-06-01

    The High Energy Physics group of the University of Texas at Arlington has been developing gas electron multiplier detectors to use them as sensitive gap detectors in digital hadron calorimeters for the International Linear Collider, a future high energy particle accelerator. For this purpose, we constructed numerous GEM detectors that employ double GEM layers. In this study, two kinds of prototype GEM detectors were tested; one with 28x28 cm{sup 2} active area double GEM structure with a 3 mm drift gap, a 1 mm transfer gap and a 1 mm induction gap and the other with two 3x3 cm{sup 2} GEM foils in the amplifier stage with a 5 mm drift gap, a 2 mm transfer gap and a 1 mm induction gap. The detectors' characteristics from exposure to high-energy charged particles and other radiations were measured using cosmic rays and {sup 55}Fe radioactive source. From the {sup 55}Fe tests, we observed two well separated characteristic X-ray emission peaks and confirmed the detectors' functionality. We also measured chamber gains to be over 6000 at a high voltage of 395 V across each GEM electrode. The responses to cosmic rays show the spectra that fit well to Landau distributions as expected from minimum ionizing particles.

  18. Using GEM-encoded guidelines to generate medical logic modules.

    PubMed Central

    Agrawal, A.; Shiffman, R. N.

    2001-01-01

    Among the most effective strategies for changing the process and outcomes of clinical care are those that make use of computer-mediated decision support. A variety of representation models that facilitate computer-based implementation of medical knowledge have been published, including the Guideline Elements Model (GEM) and the Arden Syntax for Medical Logic Modules (MLMs). We describe an XML-based application that facilitates automated generation of partially populated MLMs from GEM-encoded guidelines. These MLMs can be further edited and shared among Arden-compliant information systems to provide decision support. Our work required three steps: (a) Knowledge extraction from published guideline documents using GEM, (b) Mapping GEM elements to the MLM slots, and (c) XSL transformation of the GEM-encoded guideline. Processing of a sample guideline generated 15 MLMs, each corresponding to a conditional or imperative element in the GEM structure. Mechanisms for linking various MLMs are necessary to represent the complexity of logic typical of a guideline. PMID:11825147

  19. MIT January Operational Internship Experience

    NASA Technical Reports Server (NTRS)

    Bosanac, Natasha; DeVivero, Charlie; James, Jillian; Perez-Martinez, Carla; Pino, Wendy; Wang, Andrew; Willett, Ezekiel; Williams, Kwami

    2010-01-01

    This viewgraph presentation describes the MIT January Operational Internship Experience (JOIE) program. The topics include: 1) Landing and Recovery; 2) Transportation; 3) Shuttle Processing; 4) Constellation Processing; 5) External Tank; 6) Launch Pad; 7) Ground Operations; 8) Hypergolic Propellants; 9) Environmental; 10) Logistics; 11) Six Sigma; 12) Systems Engineering; and 13) Human Factors.

  20. 3D Observation of GEMS by Electron Tomography

    NASA Technical Reports Server (NTRS)

    Matsuno, Junya; Miyake, Akira; Tsuchiyama, Akira; Nakamura-Messenger, Keiko; Messenger, Scott

    2014-01-01

    Amorphous silicates in chondritic porous interplanetary dust particles (CP-IDPs) coming from comets are dominated by glass with embedded metal and sulfides (GEMS). GEMS grains are submicron-sized rounded objects (typically 100-500) nm in diameter) with anaometer-sized (10-50 nm) Fe-Ni metal and sulfide grains embedded in an amorphous silicate matrix. Several formation processes for GEMS grains have been proposed so far, but these models are still being debated [2-5]. Bradley et al. proposed that GEMS grains are interstellar silicate dust that survived various metamorphism or alteration processes in the protoplanetary disk and that they are amorphiation products of crystalline silicates in the interstellar medium by sputter-deposition of cosmic ray irradiation, similar to space weathering [2,4]. This consideration is based on the observation of nano-sized crystals (approximately 10 nm) called relict grains in GEMS grains and their shapes are pseudomorphs to the host GEMS grains. On the other hand, Keller and Messenger proposed that most GEMS formed in the protoplanetary disk as condensates from high temperature gas [3,5]. This model is based on the fact that most GEMS grains have solar isotopic compositions and have extremely heterogeneous and non-solar elemental compositions. Keller and Messenger (2011) also reported that amorphous silicates in GEMS grains are surrounded by sulfide grains, which formed as sulfidization of metallic iron grains located on the GEMS surface. The previous studies were performed with 2D observation by using transmission electron microscopy (TEM) or scanning TEM (STEM). In order to understand the structure of GEMS grains described above more clearly, we observed 3D structure of GEMS grains by electron tomography using a TEM/STEM (JEM-2100F, JEOL) at Kyoto University. Electron tomography gives not only 3D structures but also gives higher spatial resolution (approximately a few nm) than that in conventional 2D image, which is restricted by

  1. Embedded controller for GEM detector readout system

    NASA Astrophysics Data System (ADS)

    Zabołotny, Wojciech M.; Byszuk, Adrian; Chernyshova, Maryna; Cieszewski, Radosław; Czarski, Tomasz; Dominik, Wojciech; Jakubowska, Katarzyna L.; Kasprowicz, Grzegorz; Poźniak, Krzysztof; Rzadkiewicz, Jacek; Scholz, Marek

    2013-10-01

    This paper describes the embedded controller used for the multichannel readout system for the GEM detector. The controller is based on the embedded Mini ITX mainboard, running the GNU/Linux operating system. The controller offers two interfaces to communicate with the FPGA based readout system. FPGA configuration and diagnostics is controlled via low speed USB based interface, while high-speed setup of the readout parameters and reception of the measured data is handled by the PCI Express (PCIe) interface. Hardware access is synchronized by the dedicated server written in C. Multiple clients may connect to this server via TCP/IP network, and different priority is assigned to individual clients. Specialized protocols have been implemented both for low level access on register level and for high level access with transfer of structured data with "msgpack" protocol. High level functionalities have been split between multiple TCP/IP servers for parallel operation. Status of the system may be checked, and basic maintenance may be performed via web interface, while the expert access is possible via SSH server. System was designed with reliability and flexibility in mind.

  2. Forward GEM Tracker (FGT) at STAR

    NASA Astrophysics Data System (ADS)

    Surrow, Bernd

    2012-10-01

    As part of our program to understand the internal structure of the proton, we have and will continue mid-rapidity (-1<η<1) W and di-jet measurements in p+p collisions at √s = 500GeV. The ongoing STAR W program is exploring the longitudinal spin contribution of anti-u and anti-d quarks to the proton spin. The gluon spin contribution can be probed through di-jet measurements. The Forward GEM Tracker (FGT) at STAR will enhance the charged sign separation for high pT tracks in the pseudo-rapidity range of 1.0<η<2.0, and therefore allows an extension of W and di-jet measurements at forward pseudo-rapidity. We will present the status of the FGT assembly and completion along with projections for future W and di-jet measurements. We will discuss studies that explore the possibilities of using the FGT to reconstruct jets in the forward direction.

  3. GEMS: The destiny of Blue Spheroidal Galaxies

    NASA Astrophysics Data System (ADS)

    Häußler, Boris; Bell, Eric F.; Barden, Marco; McIntosh, Daniel H.; Rix, Hans-Walter; Borch, Andrea; Beckwith, Steven V. W.; Caldwell, John A. R.; Heymans, Catherine; Jahnke, Knud; Jogee, Shardha; Koposov, Sergey E.; Meisenheimer, Klaus; Peng, Chien Y.; Sánchez, Sebastian F.; Somerville, Rachel S.; Wisotzki, Lutz; Wolf, Christian

    2007-05-01

    One of the key predictions of hierarchical galaxy formation models is that a significant fraction of elliptical galaxies form in late merging events. One of the most important observations of such an assembly is the existence of blue spheroidal galaxies, which have spheroid-dominated morphologies and blue colors indicating recent star formation, as an intermediate step in the evolution of elliptical galaxies. We present results from the GEMS survey showing the properties of these galaxies derived from 2-D galaxy fitting of the ˜8000 galaxies with photometric redshifts in the 28'x28' HST mosaic. For the first time we were able to divide the observed population of blue elliptical galaxies into sub-populations of different stellar masses. We found that massive blue ellipticals are likely to be the progenitors of red elliptical galaxies while low-mass blue ellipticals have half-light radii considerably in excess of those measured for low-mass present day elliptical galaxies and instead have larger sizes similar to present-day disk-dominated systems with substantial bulges (see Figure)

  4. Correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 and estimated mercury emissions in China, South Asia, Indochinese Peninsula, and Central Asia derived from observations in northwest and southwest China

    NASA Astrophysics Data System (ADS)

    Fu, X. W.; Zhang, H.; Lin, C.-J.; Feng, X.; Zhou, L. X.; Fang, S. X.

    2014-09-01

    Correlation analysis between atmospheric mercury (Hg) and other trace gases are useful for identification of sources and constraining regional estimated Hg emissions. Emissions of Hg in Asia contribute significantly to the global budget of atmospheric Hg. However, due to the lack of reliable data on the source strength, large uncertainties remain in the emission inventories of Hg in Asia. In the present study, we calculated the correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 for mainland China, South Asia, Indochinese Peninsula, and Central Asia using the ground-based observations at three remote sites in northwest and southwest China, and applied the values to estimate GEM emissions in the four source regions. The geometric mean of the GEM / CO correlation slopes for mainland China, South Asia, Indochinese Peninsula, and Central Asia were 7.3 ± 4.3, 7.8 ± 6.4, 7.8 ± 5.0, and 13.4 ± 9.5 pg m-3 ppb-1, respectively. The values in the same source regions were 240 ± 119, 278 ± 164, 315 ± 289 pg m-3 ppm-1 for the GEM / CO2 correlation slopes; and 33.3 ± 30.4, 27.4 ± 31.0, 23.5 ± 15.3, and 20.5 ± 10.0 pg m-3 ppb-1 for the GEM / CH4 correlation slopes, respectively. These values were the first reported correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 in four important source regions of Asia except the GEM / CO ratios in mainland China. The correlation slopes of GEM / CO, GEM / CO2 and GEM / CH4 in Asia were relatively higher than those observed in Europe, North America and South Africa, which may highlight GEM emissions from non-ferrous smelting, mercury mining, natural sources and historical deposited mercury (re-emission) in Asia. Using the observed GEM / CO and GEM / CO2 slopes, and the recently reported emission inventories of CO and CO2, the annual GEM emissions in mainland China, South Asia, Indochinese Peninsula, and Central Asia were estimated to be in the ranges of 1071-1187 t, 340-470 t, 125 t, and 54-90 t, respectively. The estimate

  5. Innovative genomic collaboration using the GENESIS (GEM.app) platform.

    PubMed

    Gonzalez, Michael; Falk, Marni J; Gai, Xiaowu; Postrel, Richard; Schüle, Rebecca; Zuchner, Stephan

    2015-10-01

    Next-generation sequencing has led to an unparalleled pace of Mendelian disease gene discovery in recent years. To address the challenges of analysis and sharing of large datasets, we had previously introduced the collaborative web-based GEM.app software [Gonzalez et al., ]. Here, we are presenting the results of using GEM.app over nearly 3 years and introducing the next generation of this platform. First, GEM.app has been renamed to GENESIS since it is now part of "The Genesis Project" (501c3), a not-for-profit foundation that is committed to providing the best technology to enable research scientists and to connecting patients and clinicians to genomic information. Second, GENESIS (GEM.app) has grown to nearly 600 registered users from 44 countries, who have collectively achieved 62 gene identifications or published studies that have expanded phenotype/genotype correlations. Our concept of user-driven data sharing and matchmaking is now the main cause for gene discoveries within GENESIS. In many of these findings, researchers from across the globe have been connected, which gave rise to the genetic evidence needed to successfully pinpoint-specific gene mutations that explained patients' disease. Here, we present an overview of the various novel insights that have been made possible through the data-sharing capabilities of GENESIS/GEM.app. PMID:26173844

  6. Development of Resistive Electrode Gas Electron Multiplier (RE-GEM)

    NASA Technical Reports Server (NTRS)

    Yoshikawa, A.; Tamagawa, T.; Iwahashi, T.; Asami, F.; Takeuchi, Y.; Hayato, A.; Hamagaki, H.; Gunji, T.; Akimoto, R.; Nukariya, A.; Hayashi, S.; Ueno, K.; Ochi, A.; Oliveria, R.

    2012-01-01

    We successfully produced Resistive-Electrode Gas Electron Multiplier (RE-GEM) which has resistive electrodes instead of the metal ones which are employed for the standard GEM foils. RE-GEM has a resistive electrode of 25 micron-thick and an insulator layer of 100 micron-thick. The hole structure of RE-GEM is a single conical with the wider and narrower hole diameters of 80 micron and 60 micron, respectively. A hole pitch of RE-GEM is 140 micron. We obtained the maximum gain of about 600 and the typical energy resolution of about 20% (FWHM) at an applied voltage between the resistive electrodes of 620 V, using a collimated 8 keV X-rays from a generator in a gas mixture of 70% Ar and 30% CO2 by volume at the atmospheric pressure. We measured the effective gain as a function of the electric field of the drift region and obtained the maximum gain at an drift field of 0.5 kV/cm.

  7. Continuous health monitoring of graphite epoxy motorcases (GEM)

    NASA Astrophysics Data System (ADS)

    Finlayson, Richard D.; Luzio, Marco A.; Miller, Ronnie K.; Pollock, Adrian A.

    2003-08-01

    With the increasing use of advanced composite materials in aircraft, automobiles, military hardware, and aerospace composites (such as rocket motorcases) a sizable need for composite health assessment measures exist, particularly where there is risk of failure due to high mechanical and thermal stresses. For most epoxy-based laminate composites, even low-momentum impacts can lead to "barely visible impact damage" (BVD), corresponding to a significant weakening of the composite. This weakening can lead to sudden and catastrophic failure when the material is subjected to normal operating loads. Following the explosion of Delta 241 (IIR-1) on Jaunary 17th, 1997, the failure investigation board concluded that an entire fleet of Graphite Epoxy Motorcases (GEMs) should be instrumented with a health monitoring system. This system would provide continuous structural health data on the GEM from initial acceptance testing through final erection on the launch pad. The result presented here contribute significantly to the understanding of the acoustic properties of the GEM casing, and make a substantial advancement in the theoretical phase of the source location algorithm development. When the system is complete it will continuously monitor the structural health of the GEMs, communicate wirelessly with base stations, operate autonomously for extended periods, and fit unobtrusively on the GEM itself.

  8. Educational Outreach at MIT PSFC

    NASA Astrophysics Data System (ADS)

    Rivenberg, P.; Thomas, P.; Censabella, V.

    2001-10-01

    At the MIT PSFC student and staff volunteers work together to increase the public's knowledge of fusion and plasma-related experiments. Seeking to generate excitement about science and engineering, the PSFC hosts a number of outreach activities throughout the year, including Middle and High School Outreach Days. Key to the success of these tours is the interactive ``C-Mod, Jr.," which helps students understand magnetic confinement in MIT's Alcator C-Mod tokamak. The PSFC also has an in-school science demonstration program on the theme of magnetism. As ``Mr. Magnet" Technical Supervisor Paul Thomas brings a truck-load of hands-on demonstrations to K-12 schools, challenging students to help him with experiments. While teaching fundamentals of magnetism and electricity he shows that science is fun for all, and that any student can have a career in science. This year he reached 77 schools -- 30,000 teachers and students. We have also collaborated with the MIT Museum to create an interactive plasma demonstration device which students and the general public can use to create plasmas from different gasses. Pinch and deflection magnets are moveable along the axis of the display, allowing investigation of the magnetic behavior of plasmas.

  9. The Bisa GEM-Mars GCM

    NASA Astrophysics Data System (ADS)

    Neary, Lori; Daerden, Frank

    2013-04-01

    GEM-Mars is a three-dimensional general circulation model of the Mars atmosphere extending from the surface to approximately 170 km based on the latest version of the GEM (Global Environmental Mesoscale) model, the operational data assimilation and weather forecasting system for Canada [Côté et al., 1998]. The dynamical core is an implicit two-time-level semi-Lagrangian scheme on an Arakawa C-grid with a terrain-following, log-hydrostatic-pressure vertical coordinate discretized on a Charney-Phillips grid. The model has both a hydrostatic and non-hydrostatic formulation, providing a single platform for simulations on a variety of horizontal scales. The model code is fully parallelized using OMP and MPI. The GCM includes the relevant physical processes such as CO2 condensation, planetary boundary layer mixing, gravity wave drag and surface parameterizations. A simple water cycle, basic gas-phase chemistry and passive tracers are also included in the model. Because of the vertical extent of the model, UV heating, non-LTE effects and molecular diffusion are also included. Dust is prescribed using the MGS scenario for total opacities and a Conrath profile shape. In the dust radiative transfer code, dust optical properties are based on the Wolff et al [2006, 2009] data. Temperatures in the lower and middle atmosphere have been evaluated using TES [Smith, 2004] and MCS [Kleinbohl et al. 2009] data. Winds and atmospheric circulation (mass stream functions) have been compared with the literature and show a good correspondence to other Mars GCMs. In parallel, active lifting and settling of size-distributed dust has also been implemented. The soil model has been improved to better match surface and near-surface temperatures from the Viking Landers, Phoenix [Davy et al. 2010], and TES. Near-surface winds and friction velocities have been compared with the literature and show reasonable performance. Condensation of CO2 in surface ice has been validated using CO2 ice mass

  10. Correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

    NASA Astrophysics Data System (ADS)

    Fu, X. W.; Zhang, H.; Lin, C.-J.; Feng, X. B.; Zhou, L. X.; Fang, S. X.

    2015-01-01

    Correlation analyses between atmospheric mercury (Hg) and other trace gases are useful for identification of sources and constraining regional Hg emissions. Emissions of Hg in Asia contribute significantly to the global budget of atmospheric Hg. However, due to the lack of reliable data on the source strength, large uncertainties remain in the emission inventories of Hg in Asia. In the present study, we calculated the correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 for mainland China, South Asia, the Indochinese Peninsula, and Central Asia using the ground-based observations at three remote sites in northwestern and southwestern China, and applied these values to estimate GEM emissions in the four source regions. The geometric mean GEM / CO correlation slopes for mainland China, South Asia, the Indochinese Peninsula, and Central Asia were 7.3 ± 4.3, 7.8 ± 6.4, 7.8 ± 5.0, and 13.4 ± 9.5 pg m-3 ppb-1, respectively, and values in the same source regions were 33.3 ± 30.4, 27.4 ± 31.0, 23.5 ± 15.3, and 20.5 ± 10.0 pg m-3 ppb-1 for the GEM / CH4 correlation slopes, respectively. The geometric means of GEM / CO2 correlation slopes for mainland China, South Asia, and Central Asia were 240 ± 119, 278 ± 164, 315 ± 289 pg m-3 ppm-1, respectively. These values were the first reported correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 in four important source regions of Asia, not including the GEM / CO ratios in mainland China. The correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 in Asia were relatively higher than those observed in Europe, North America, and South Africa, which may highlight GEM emissions from non-ferrous smelting, large-scale and artisanal mercury and gold production, natural sources, and historically deposited mercury (re-emission) in Asia. Using the observed GEM / CO and GEM / CO2 slopes, and the recently reported emission inventories of CO and CO2, the annual GEM emissions in mainland China, South Asia, the Indochinese

  11. The GEMS X-Ray Polarlimeter: Instrument Concpet and Calibration Requirements

    NASA Technical Reports Server (NTRS)

    Jahoda, Keith

    2010-01-01

    The instrument and detector concepts for the Gravity and Extreme Magnetism Small Explorer (GEMS) X-ray polarimetry mission will be presented. The calibration requirements for astrophysical X-ray polarimeters in general and GEMS in particular will be discussed.

  12. GEM400: A front-end chip based on capacitor-switch array for pixel-based GEM detector

    NASA Astrophysics Data System (ADS)

    Li, H. S.; Jiang, X. S.; Liu, G.; Wang, N.; Sheng, H. Y.; Zhuang, B. A.; Zhao, J. W.

    2012-03-01

    The upgrade of Beijing Synchrotron Radiation Facility (BSRF) needs two-dimensional position-sensitive detection equipment to improve the experimental performance. Gas Electron Multiplier (GEM) detector, in particular, pixel-based GEM detector has good application prospects in the domain of synchrotron radiation. The read-out of larger scale pixel-based GEM detector is difficult for the high density of the pixels (PAD for collecting electrons). In order to reduce the number of cables, this paper presents a read-out scheme for pixel-based GEM detector, which is based on System-in-Package technology and ASIC technology. We proposed a circuit structure based on capacitor switch array circuit, and design a chip GEM400, which is a 400 channels ASIC. The proposed circuit can achieve good stability and low power dissipation. The chip is implemented in a 0.35μm CMOS process. The basic functional circuitry in ths chip includes analog switch, analog buffer, voltage amplifier, bandgap and control logic block, and the layout of this chip takes 5mm × 5mm area. The simulation results show that the chip can allow the maximum amount of input charge 70pC on the condition of 100pF external integrator capacitor. Besides, the chip has good channel uniformity (INL is better than 0.1%) and lower power dissipation.

  13. An infrared spectral match between GEMS and interstellar grains

    NASA Technical Reports Server (NTRS)

    Bradley, J. P.; Keller, L. P.; Snow, T. P.; Hanner, M. S.; Flynn, G. J.; Gezo, J. C.; Clemett, S. J.; Brownlee, D. E.; Bowey, J. E.

    1999-01-01

    Infrared spectral properties of silicate grains in interplanetary dust particles (IDPs) were compared with those of astronomical silicates. The approximately 10-micrometer silicon-oxygen stretch bands of IDPs containing enstatite (MgSiO3), forsterite (Mg2SiO4), and glass with embedded metal and sulfides (GEMS) exhibit fine structure and bandwidths similar to those of solar system comets and some pre-main sequence Herbig Ae/Be stars. Some GEMS exhibit a broad, featureless silicon-oxygen stretch band similar to those observed in interstellar molecular clouds and young stellar objects. These GEMS provide a spectral match to astronomical "amorphous" silicates, one of the fundamental building blocks from which the solar system is presumed to have formed.

  14. Readout of TPC Tracking Chambers with GEMs and Pixel Chip

    SciTech Connect

    Kadyk, John; Kim, T.; Freytsis, M.; Button-Shafer, J.; Kadyk, J.; Vahsen, S.E.; Wenzel, W.A.

    2007-12-21

    Two layers of GEMs and the ATLAS Pixel Chip, FEI3, have been combined and tested as a prototype for Time Projection Chamber (TPC) readout at the International Linear Collider (ILC). The double-layer GEM system amplifies charge with gain sufficient to detect all track ionization. The suitability of three gas mixtures for this application was investigated, and gain measurements are presented. A large sample of cosmic ray tracks was reconstructed in 3D by using the simultaneous timing and 2D spatial information from the pixel chip. The chip provides pixel charge measurement as well as timing. These results demonstrate that a double GEM and pixel combination, with a suitably modified pixel ASIC, could meet the stringent readout requirements of the ILC.

  15. Gravitational field models for the earth (GEM 1 and 2)

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Wagner, C. A.; Smith, D. E.; Andson, M. L.; Brownd, J. E.; Richardson, J. A.

    1972-01-01

    Two models of the earth's gravitational field have been computed at Goddard Space Flight Center. The first, Goddard Earth Model 1 (GEM 1), has been derived from satellite tracking data. The second, Goddard Earth Model 2 (GEM 2), has been derived from a combination of satellite tracking and surface gravimetric data. The geopotential models are represented in spherical harmonics complete to degree and order 16 for the combined solution and complete to degree and order 12 for the satellite solution. Both solutions include zonal terms to degree 21 and related satellite resonant coefficients to degree 22. The satellite data consisted primarily of optical data processed on 300 weekly orbital arcs for 25 close earth satellites. Surface gravity data were employed in the form of 5 deg x 5 deg mean free-air gravity anomalies providing about 70% world coverage. Station locations were obtained for 46 tracking sites by combining electronic, laser, and additional optical tracking data with the above satellite data. Analysis of the radial positions of these stations and a value of mean gravity on the geoid indicated a mean equatorial radius for the earth of about 6378145 meters. Results of geopotential tests on satellite data not used in the solution show that better agreement was obtained with the GEM 1 and GEM 2 models than with the 1969 Smithsonian Standard Earth 2 model.

  16. On algorithmic optimization of histogramming functions for GEM systems

    NASA Astrophysics Data System (ADS)

    Krawczyk, Rafał D.; Czarski, Tomasz; Kolasinski, Piotr; Poźniak, Krzysztof T.; Linczuk, Maciej; Byszuk, Adrian; Chernyshova, Maryna; Juszczyk, Bartlomiej; Kasprowicz, Grzegorz; Wojenski, Andrzej; Zabolotny, Wojciech

    2015-09-01

    This article concerns optimization methods for data analysis for the X-ray GEM detector system. The offline analysis of collected samples was optimized for MATLAB computations. Compiled functions in C language were used with MEX library. Significant speedup was received for both ordering-preprocessing and for histogramming of samples. Utilized techniques with obtained results are presented.

  17. The Gravity and Extreme Magnetism Small Explorer (GEMS)

    NASA Technical Reports Server (NTRS)

    Kallman, T. R.

    2011-01-01

    The Gravity and Extreme Magnetism Small Explorer (GEMS) was selected by NASA for flight in 2014 to make a sensitive search for X-ray polarization from a wide set of source classes, including stellar black holes, Seyfert galaxies and quasars, blazars, rotation and accretion-powered pulsars, magnetars, shell supernova remnants and pulsar wind nebulae. Among the primary scientific objectives are determining the effects of the spin of black holes and the geometry of supermassive black hole accretion, determining the configurations of the magnetic fields and the X-ray emission of magnetars, and determining the magnetic structure of the supernova shocks in which cosmic rays are accelerated. GEMS will observe 23 targets during a 16 month prime mission, in observations that will be able to reach predicted levels of polarization. The mission can be extended to provide a guest observer phase. The GEMS instrument has time projection chamber polarimeters with high 2-10 keV efficiency at the focus of thin foil mirrors. The 4.5 m focal length mirrors will be deployed on an extended boom. The spacecraft with the instrument is rotated with a period of about 10 minutes to enable measurement and correction of systematic errors. A small Bragg reflection soft X-ray experiment takes advantage of this rotation to obtain a measurement at 0.5 keV. The design of the GEMS instrument and the mission, the expected performance and the planned science program will be discussed.

  18. Difluoromethylation and gem-difluorocyclopropenation with difluorocarbene generated by decarboxylation.

    PubMed

    Deng, Xiao-Yun; Lin, Jin-Hong; Zheng, Jian; Xiao, Ji-Chang

    2015-05-25

    Difluoromethylation of the activated X-H bond (X = N, O and S) and aliphatic thiols, and gem-difluorocyclopropenation of alkynes with difluorocarbene generated in situ from difluoromethylene phosphobetaine (Ph3P(+)CF2CO2(-)) by decarboxylation occurred smoothly without the presence of any base or other additives. PMID:25918009

  19. The Greenhouse Gases. UNEP/GEMS Environment Library No. 1.

    ERIC Educational Resources Information Center

    United Nations Environment Programme, Nairobi (Kenya).

    Since the United Nations Environment Program (UNEP) was created, more than a dozen years ago, public understanding of the environmental issues confronting our planet has increased enormously. The Global Environment Monitoring System (GEMS) has provided several environmental assessments including urban air pollution, climate modification,…

  20. PREFACE: Science's gem: diamond science 2009 Science's gem: diamond science 2009

    NASA Astrophysics Data System (ADS)

    Mainwood, Alison; Newton, Mark E.; Stoneham, Marshall

    2009-09-01

    Natural diamond has been valued for its appearance and mechanical properties for at least two thousand years. As a gem stone diamond is unsurpassed. However, scientific work, especially in the last 20 years, has demonstrated that diamond has numerous surprising properties and many unique ones. Some of the extreme properties have been known for many years, but the true scale of diamond's other highly desirable features is still only coming to light as control in the synthesis of diamond, and hence material perfection, improves. The ultimate prize for man-made diamond is surely not in the synthesis of gem stones, but in delivering technological solutions enabled by diamond to the challenges facing our society today. If the special properties are to be exploited to their full potential, at least four crucial factors must be considered. First, there must be sufficient scientific understanding of diamond to make applications effective, efficient and economical. Secondly, the means of fabrication and control of properties have to be achieved so that diamond's role can be optimised. Thirdly, it is not enough that its properties are superior to existing materials: they must be so much better that it is worth initiating new technologies to exploit them. Finally, any substantial applications will have to address the society's major needs worldwide. The clear technology drivers for the 21st century come from the biomedical technologies, the demand for energy subject to global constraints, and the information technologies, where perhaps diamond will provide the major enabling technology [1]. The papers in this volume concern the solid state physics of diamond, and primarily concern the first two factors: understanding, and control of properties. They address many of the outstanding basic problems, such as the identification of existing defects, which affect the material's properties, both desirable and less so. Regarding future substantial applications, one paper discusses

  1. Continuous health monitoring of Graphite Epoxy Motorcases (GEM)

    NASA Astrophysics Data System (ADS)

    Finlayson, Richard D.; Schaafsma, David T.; Shen, H. Warren; Carlos, Mark F.; Miller, Ronnie K.; Shepherd, Brent

    2001-07-01

    Following the explosion of Delta 241 (IIR-1) on January 17th, 1997, the failure investigation board concluded that the Graphite Epoxy Motorcases (GEM's) should be inspected for damage just prior to launch. Subsequent investigations and feedback from industry led to an Aerospace Corporation proposal to instrument the entire fleet of GEM's with a continuous health monitoring system. The period of monitoring would extend from the initial acceptance testing through final erection on the launch pad. As this proposal demonstrates, (along with the increasing use of advanced composite materials in aircraft, automobiles, military hardware, and aerospace components such as rocket motorcases) a sizable need for composite health assessment measures exist. Particularly where continuous monitoring is required for the detection of damage from impacts and other sources of high mechanical and thermal stresses. Even low-momentum impacts can lead to barely visible impact damage (BVID), corresponding to a significant weakening of the composite. This damage, undetectable by visual inspection, can in turn lead to sudden and catastrophic failure when the material is subjected to a normal operating load. There is perhaps no system with as much potential for truly catastrophic failure as a rocket motor. We will present an update on our ongoing efforts with the United States Air Force Delta II Program Office, and The Aerospace Corporation. This will cover the development of a local, portable, surface-mounted, fiberoptic sensor based impact damage monitor designed to operate on a Delta II GEM during transport, storage, and handling. This system is designed to continuously monitor the GEMs, to communicate wirelessly with base stations and maintenance personnel, to operate autonomously for extended periods, and to fit unobtrusively on the GEM itself.

  2. Improvement in the geopotential derived from satellite and surface data /Gem 7 and 8/

    NASA Technical Reports Server (NTRS)

    Wagner, C. A.; Lerch, F. J.; Brownd, J. E.; Richardson, J. A.

    1977-01-01

    A refinement has been obtained in the earth's gravitational field by using satellite and surface data. In addition to a more complete treatment of data previously employed on 27 satellites, the new satellite solution Gem 7 (Goddard Earth Model 7) includes 64,000 laser measurements taken on seven satellites. Gem 7, containing 400 harmonic terms, is complete through degree and order 16. The companion solution Gem 8 combines the same satellite data as Gem 7 with surface gravimetry over 39% of the earth. Gem 8 is complete to degree and order 25. Extensive tests on data independent of the solution show that the undulations of the geoidal surface computed by Gem 7 have an accuracy of about 2.5 m (rms). The overall accuracy of the geoid calculated by Gem 8 is estimated to be about 4 m (rms). The new combination solution is the first to show signs of 'convection rolls' in the upper mantle below the Pacific Ocean.

  3. Positive Werkzeuge mit hohem IQ

    NASA Astrophysics Data System (ADS)

    Luik, Matthias

    Fräsen ist ein Verfahren, auf welches im modernen Produktionsprozess nicht verzichtet werden kann. Dabei stellt die zunehmende Komplexität der zu fertigenden Bauteile ganz neue Herausforderungen an ein Werkzeug. Konnten früher Bauteile nur mit hohem Aufwand durch Erodieren oder Außenräumen hergestellt werden, müssen heute bereits Fräswerkzeuge für solche Bearbeitungsaufgaben aus Zeitund Kostengründen eingesetzt werden. Dies führt dazu, dass viele Bauteile heute in einer Aufspannung bearbeitbar sind, welche früher nur durch mehrmaliges Umspannen erzeugt werden konnten. Um Bearbeitungszeiten und -kosten dabei gering zu halten, müssen aber dennoch universelle Werkzeuge eingesetzt werden, welche für verschiedenste Bearbeitungsaufgaben ausgelegt sind.

  4. GEM1: First-year modeling and IT activities for the Global Earthquake Model

    NASA Astrophysics Data System (ADS)

    Anderson, G.; Giardini, D.; Wiemer, S.

    2009-04-01

    GEM is a public-private partnership initiated by the Organisation for Economic Cooperation and Development (OECD) to build an independent standard for modeling and communicating earthquake risk worldwide. GEM is aimed at providing authoritative, open information about seismic risk and decision tools to support mitigation. GEM will also raise risk awareness and help post-disaster economic development, with the ultimate goal of reducing the toll of future earthquakes. GEM will provide a unified set of seismic hazard, risk, and loss modeling tools based on a common global IT infrastructure and consensus standards. These tools, systems, and standards will be developed in partnership with organizations around the world, with coordination by the GEM Secretariat and its Secretary General. GEM partners will develop a variety of global components, including a unified earthquake catalog, fault database, and ground motion prediction equations. To ensure broad representation and community acceptance, GEM will include local knowledge in all modeling activities, incorporate existing detailed models where possible, and independently test all resulting tools and models. When completed in five years, GEM will have a versatile, penly accessible modeling environment that can be updated as necessary, and will provide the global standard for seismic hazard, risk, and loss models to government ministers, scientists and engineers, financial institutions, and the public worldwide. GEM is now underway with key support provided by private sponsors (Munich Reinsurance Company, Zurich Financial Services, AIR Worldwide Corporation, and Willis Group Holdings); countries including Belgium, Germany, Italy, Singapore, Switzerland, and Turkey; and groups such as the European Commission. The GEM Secretariat has been selected by the OECD and will be hosted at the Eucentre at the University of Pavia in Italy; the Secretariat is now formalizing the creation of the GEM Foundation. Some of GEM's global

  5. The determination of the orbit of the Japanese satellite Ajisai and the GEM-T1 and GEM-T2 gravity field models

    NASA Technical Reports Server (NTRS)

    Sanchez, Braulio V.

    1990-01-01

    The Japanese Experimental Geodetic Satellite Ajisai was launched on August 12, 1986. In response to the TOPEX-POSEIDON mission requirements, the GSFC Space Geodesy Branch and its associates are producing improved models of the Earth's gravitational field. With the launch of Ajisai, precise laser data is now available which can be used to test many current gravity models. The testing of the various gravity field models show improvements of more than 70 percent in the orbital fits when using GEM-T1 and GEM-T2 relative to results obtained with the earlier GEM-10B model. The GEM-T2 orbital fits are at the 13-cm level (RMS). The results of the tests with the various versions of the GEM-T1 model indicate that the addition of satellite altimetry and surface gravity anomalies as additional data types should improve future gravity field models.

  6. The Dynamical Evolution of the Multiple Stellar System α Gem

    NASA Astrophysics Data System (ADS)

    Andrade, M.; Docobo, J. A.

    2015-07-01

    The sextuple system Castor (α Gem) comprises of a visual binary (Castor A and B) with an orbital period of approximately 460 years. Each of these components is a single-lined spectroscopic binary with an orbital period of only a few days. In addition, a distant double-lined spectroscopic eclipsing binary (Castor C, or YY Gem), with an orbital period of less than 1 day, is considered to be in orbit around them with a period of roughly 14 000 years or more. In this contribution, we study the long-term dynamics of this hierarchical system. Many orbital elements still remain unknown, mainly those regarding the AB-C system. Apart from the direct integration of the equations of motion for the quadruple (Aa,Ab)-(Ba,Bb) system, we also perform a qualitative analysis of the global system by means of numerical techniques in order to find the most distinctive features of its dynamics.

  7. Fast modular data acquisition system for GEM-2D detector

    NASA Astrophysics Data System (ADS)

    Kasprowicz, G.; Byszuk, Adrian; Wojeński, A.; Zienkiewicz, P.; Czarski, T.; Chernyshova, M.; Poźniak, K.; Rzadkiewicz, J.; Zabolotny, W.; Juszczyk, B.

    2014-11-01

    A novel approach to two dimensional Gas Electron Multiplier (GEM) detector readout is presented. Unlike commonly used methods, based on discriminators and analogue FIFOs, the method developed uses simulta- neously sampling high speed ADCs with fast hybrid integrator and advanced FPGA-based processing logic to estimate the energy of every single photon. Such a method is applied to every GEM strip / pixel signal. It is especially useful in case of crystal-based spectrometers for soft X-rays, 2D imaging for plasma tomography and all these applications where energy resolution of every single photon is required. For the purpose of the detector readout, a novel, highly modular and extendable conception of the measurement platform was developed. It is evolution of already deployed measurement system for JET Spectrometer.

  8. Respiratory morbidities among working children of gem polishing industries, India.

    PubMed

    Tiwari, R R; Saha, A; Parikh, J R

    2009-02-01

    There are millions of working children worldwide. In gem polishing industry, exposure to occupational hazards of dust and chemicals used in polishing of gemstone may result in respiratory symptoms and respiratory disorders. The present study included 586 exposed and 569 comparison group subjects. Data was collected through personal interview, clinical examination, and chest radiography. The respiratory morbidity was diagnosed on the basis of clinical signs and symptoms and chest radiography. The study variables included age, sex, daily working hours, and duration of exposure. The mean age of the child laborers was 11.31 +/- 5.34 years. Prevalence of respiratory morbidity was significantly high in the female child laborers. The other study variables namely age, duration of exposure, and daily working hours were found to be statistically non-significant. The prevalence of respiratory morbidity among child laborers of gem polishing industry in Jaipur was found to be 7%. PMID:19318508

  9. Structure of the Martian atmosphere from Epsilon Gem occultation observations

    NASA Technical Reports Server (NTRS)

    Hubbard, W. B.

    1982-01-01

    Information about Martian atmospheric scale heights derived from observations of the occultation of Epsilon Gem by Mars on April 8, 1976 has been collected. The observations give data in the altitude range of about 50 to 80 km. A rough, unweighted average of results so far available yields a temperatue of approximately 165 K. Excursions of about + or - 4 K about this mean may be present as a function of both altitude and areographic coordinates.

  10. Structure of the Martian atmosphere from Epsilon Gem occultation observations

    NASA Technical Reports Server (NTRS)

    Hubbard, W. B.

    1978-01-01

    Information has been collected on Martian atmospheric scale heights derived from observations of the occultation of Epsilon Gem by Mars on Apr. 8, 1976; the observations give data in the altitude range of approximately 50-80 km. A rough, unweighted average of results so far available yields a temperature of approximately 165 K. Excursions of plus or minus 40 K about this mean may be present as a function of both altitude and areographic coordinates.

  11. The gas electron multiplier (GEM): Operating principles and applications

    NASA Astrophysics Data System (ADS)

    Sauli, Fabio

    2016-01-01

    Introduced by the author in 1997, The Gas Electron Multiplier (GEM) constitutes a powerful addition to the family of fast radiation detectors; originally developed for particle physics experiments, the device and has spawned a large number of developments and applications; a web search yields more than 400 articles on the subject. This note is an attempt to summarize the status of the design, developments and applications of the new detector.

  12. Serial data acquisition for GEM-2D detector

    NASA Astrophysics Data System (ADS)

    Kolasinski, Piotr; Pozniak, Krzysztof T.; Czarski, Tomasz; Linczuk, Maciej; Byszuk, Adrian; Chernyshova, Maryna; Juszczyk, Bartlomiej; Kasprowicz, Grzegorz; Wojenski, Andrzej; Zabolotny, Wojciech; Zienkiewicz, Pawel; Mazon, Didier; Malard, Philippe; Herrmann, Albrecht; Vezinet, Didier

    2014-11-01

    This article debates about data fast acquisition and histogramming method for the X-ray GEM detector. The whole process of histogramming is performed by FPGA chips (Spartan-6 series from Xilinx). The results of the histogramming process are stored in an internal FPGA memory and then sent to PC. In PC data is merged and processed by MATLAB. The structure of firmware functionality implemented in the FPGAs is described. Examples of test measurements and results are presented.

  13. Reaction of alpha-gem-trichlorocarbonyl compounds with conjugated alkadienes

    SciTech Connect

    Startsev, V.V.; Zubritskii, L.M.; Gorbunkov, V.D.; Petrov, A.A.

    1986-04-10

    Chloral and gem-trichloroacetone add to 1,3-alkadienes in the presence of copper(I) chloride with the formation of the corresponding ..gamma..,delta-unsaturated ..cap alpha..,..cap alpha..epsilon-trichlorocarbonyl compounds as mixtures of the E and Z isomers in a ratio in the order of 85:15. The reaction takes place under mild conditions and gives a high yield of the final products.

  14. A refined gravity model from Lageos /GEM-L2/

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Klosko, S. M.; Patel, G. B.

    1982-01-01

    Lageos satellite laser ranging (SLR) data taken over a 2.5 yr period were employed to develop the Goddard Earth Model GEM-L2, a refined gravity field model. Additional data was gathered with 30 other satellites, resulting in spherical harmonics through degree and order 20, based on over 600,000 measurements. The Lageos data was accurate down to 10 cm, after which the GEM 9 data were used to make adjustments past order 7. The resolution of long wavelength activity, through degree and order 4, was made possible by the Lageos data. The GEM-L2 model features a 20 x 20 geopotential, tracking station coordinates (20), 5-day polar motion and A1-UT1 values, and a GM value of 398,600.607 cu km/sq sec. The accuracy of station positioning has been raised to within 6 cm total position globally and within 1.8 cm in baselines. It is concluded that SLR is useful for measuring tectonic plate motions and inter-plate deformations.

  15. GEMS: a web server for biclustering analysis of expression data

    PubMed Central

    Wu, Chang-Jiun; Kasif, Simon

    2005-01-01

    The advent of microarray technology has revolutionized the search for genes that are differentially expressed across a range of cell types or experimental conditions. Traditional clustering methods, such as hierarchical clustering, are often difficult to deploy effectively since genes rarely exhibit similar expression pattern across a wide range of conditions. Biclustering of gene expression data (also called co-clustering or two-way clustering) is a non-trivial but promising methodology for the identification of gene groups that show a coherent expression profile across a subset of conditions. Thus, biclustering is a natural methodology as a screen for genes that are functionally related, participate in the same pathways, affected by the same drug or pathological condition, or genes that form modules that are potentially co-regulated by a small group of transcription factors. We have developed a web-enabled service called GEMS (Gene Expression Mining Server) for biclustering microarray data. Users may upload expression data and specify a set of criteria. GEMS then performs bicluster mining based on a Gibbs sampling paradigm. The web server provides a flexible and an useful platform for the discovery of co-expressed and potentially co-regulated gene modules. GEMS is an open source software and is available at . PMID:15980544

  16. UV emission from he M1 supergiant TV Gem

    NASA Technical Reports Server (NTRS)

    Michalitsianos, A. G.; Kafatos, M.

    1982-01-01

    Low and high dispersion ultraviolet spectra were obtained of the M1 supergiant TV Gem with IUE. Previous IUE observations of this late type supergiant revealed unexpected UV continuum emission, perhaps arising from an early B companion. Low resolution spectra obtained approximately one year apart suggest that the strong Si III in combination perhaps with O I at wavelengths approximately 1300 A varies considerably with time. Large variation in the column density is required to explain these changes. Sporadic mass expulsion with mass loss rates dM/dt approximately 0.00001 solar mass yr minus 1st power from the M supergiant could lead to a dense circumstellar wind near the hot early companion, and thus could account for these observed variations in equivalent width. The high resolution spectrum in the 2000 to 3200 A wavelength range is characterized by narrow absorption lines primarily due to Fe II, Mn II and Mg II (h and k), which are skewed in profile with an extended red wing. This profile structure is tentatively attributed to interstellar absorption and an intervening differentially moving cloud in the direction of Gem OB1, of which TV Gem is a known association member.

  17. Targeting SMN to Cajal bodies and nuclear gems during neuritogenesis

    PubMed Central

    Navascues, Joaquin; Berciano, Maria T.; Tucker, Karen E.

    2006-01-01

    Neurite outgrowth is a central feature of neuronal differentiation. PC12 cells are a good model system for studying the peripheral nervous system and the outgrowth of neurites. In addition to the dramatic changes observed in the cytoplasm, neuronal differentiation is also accompanied by striking changes in nuclear morphology. The large and sustained increase in nuclear transcription during neuronal differentiation requires synthesis of a large number of factors involved in pre-mRNA processing. We show that the number and composition of the nuclear subdomains called Cajal bodies and gems changes during the course of N-ras-induced neuritogenesis in the PC12-derived cell line UR61. The Cajal bodies found in undifferentiated cells are largely devoid of the survival of motor neurons (SMN) protein product. As cells shift to a differentiated state, SMN is not only globally upregulated, but is progressively recruited to Cajal bodies. Additional SMN foci (also known as Gemini bodies, gems) can also be detected. Using dual-immunogold labeling electron microscopy and mouse embryonic fibroblasts lacking the coilin protein, we show that gems clearly represent a distinct category of nuclear body. PMID:15164213

  18. The TOTEM GEM Telescope (T2) at the LHC

    NASA Astrophysics Data System (ADS)

    Quinto, M.; Berretti, M.; David, E.; Garcia, F.; Greco, V.; Heino, J.; Hilden, T.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Oliveri, E.; Ropelewski, L.; Scribano, A.; Turini, N.; van Stenis, M.

    2011-06-01

    The TOTEM T2 telescope will measure inelastically produced charged particles in the forward region of the LHC Interaction Point 5. Each arm of the telescope consists in a set of 20 triple-GEM (Gas Electron Multiplier) detectors with tracking and trigger capabilities. The GEM technology has been considered for the design of TOTEM very forward T2 telescopes thanks to its characteristics: large active areas, good position and timing resolution, excellent rate capability and radiation hardness. Each of the four T2 half arms has been fully assembled and equipped with electronics at CERN and systematically tested in the SPS beam line H8 in 2008/09. After some optimization, the operation of the GEM chambers was fully satisfactory and the T2 telescopes were installed and commissioned in their final positions at the LHC interaction point. During the first LHC run (December 2009) the T2 telescopes have collected data, at 900 GeV and 2.36 TeV. We will present here the performances of the detector and the preliminary results obtained using the data collected.

  19. Development of near infrared spectrometer for gem materials study

    NASA Astrophysics Data System (ADS)

    Jindata, W.; Meesiri, W.; Wongkokua, W.

    2015-07-01

    Most of gem materials can be characterized by infrared absorption spectroscopy. Normally, mid infrared absorption technique has been applied for investigating fundamental vibrational modes. However, for some gem materials, such as tourmaline, NIR is a better choice due to differentiation. Most commercial NIR spectrometers employ complicated dispersive grating or Fourier transform techniques. In this work, we developed a filter type NIR spectrometer with the availability of high efficiency and low-cost narrow bandpass NIR interference filters to be taught in a physics laboratory. The instrument was designed for transmission-mode configuration. A 50W halogen lamp was used as NIR source. There were fourteen NIR filters mounted on a rotatory wheel for wavelength selection ranging from 1000-1650 nm with steps of 50 nm. A 1.0 mm diameter of InGaAs photodiode was used as the detector for the spectrometer. Hence, transparent gem materials can be used as samples for experiment. Student can learn vibrational absorption spectroscopy as well as Beer-Lambert law from the development of this instrument.

  20. Improvement in the geopotential derived from satellite and surface data (GEM 7 and 8)

    NASA Technical Reports Server (NTRS)

    Wagner, C. A.; Lerch, F. J.; Brownd, J. E.; Richardson, J. A.

    1976-01-01

    A refinement was obtained in the earth's gravitational field using satellite and surface data. In addition to a more complete treatment of data previously employed on 27 satellites, the new satellite solution (Goddard Earth Model 7) includes 64,000 laser measurements taken on 7 satellites during the international satellite geodesy experiment (ISAGEX) program. The GEM 7, containing 400 harmonic terms, is complete through degree and order 16. The companion solution GEM 8 combines the same satellite data as in GEM 7 with surface gravimetry over 39% of the earth. The GEM 8 is complete to degree and order 25. Extensive tests on data independent of the solution show that the undulation of the geoidal surface computed by GEM 7 has an accuracy of about 3m (rms). The overall accuracy of the geoid estimated by GEM 8 is estimated to be about 4-1/4m (rms), an improvement of almost 1m over previous solutions.

  1. Unfälle mit Pkw

    NASA Astrophysics Data System (ADS)

    Burg, Heinz

    Der Verkehrsunfall ereignete sich innerorts auf einer Kreuzung mit rechts vor links Regelung. Es galt dort die allgemeine Geschwindigkeitsbegrenzung auf 50 km/h. Zur Unfallzeit war es hell und trocken. Die Fahrbahn hatte eine Schwarzdecke.

  2. Synthesis of GEMS from Shock-accelerated Crystalline Dust in Superbubbles: Model and Predictions

    NASA Technical Reports Server (NTRS)

    Westphal, Andrew J.; Bradley, John P.

    2005-01-01

    GEMS (Glass Embedded with Metals and Sulfides) are highly enigmatic yet common components of anhydrous IDPs. We have recently proposed a model of GEMS formation from shock-accelerated crystalline dust in superbubbles[1] which explains the three most perplexing properties of GEMS: pseudomorphism[2], their chemistry[3], and their size range. In this Abstract, we briefly review the main points of the model, and suggest tests that will either prove or rule out this hypothesis.

  3. Workstation-assisted education at MIT

    NASA Astrophysics Data System (ADS)

    Champine, George A.

    1992-06-01

    MIT launched a major new initiative called Project Athena in 1983 to improve the quality of education through the introduction of a high-quality computing infrastructure throughout the campus. Implementation of the Project Athena computing environment required eight years, cost about 100 million, and was sponsored by Digital Equipment and IBM in addition to MIT. The Athena computing environment is based almost entirely on workstations from these two vendors using the Unix operating system. Project Athena is now complete. The resulting computer system has been turned over to the campus computing organization for ongoing operation and maintenance. The computing environment available at MIT for education has been significantly improved. Students are graduating today that have never known life at MIT without the ubiquitous availability of high-quality computing. This article provides an overview of the initial objectives and strategies of Project Athena at MIT relative to its educational use. The specific strategies that MIT employed in the use of work-stations in educational are then described. These strategies are contrasted with other available strategies. Specific examples of the use of workstations are presented. An important element in current and future education delivery is multimedia. Athena in conjunction with the MIT Media Lab has one of the largest efforts in multimedia development of any of the universities, and MIT is using multimedia in education on a daily basis. A new laboratory, the Center for Educational Computing Initiatives, has been established with a major focus on multimedia. Finally the lessons learned from Athena relative to its primary objective — that of improving education — are reviewed.

  4. Photovoltaik Hybrid-Solarzellen mit Nanopartikeln

    NASA Astrophysics Data System (ADS)

    Leute, Angelika

    2004-09-01

    Die organische Photovoltaik auf der Basis halbleitender Polymere bietet eine kostengünstige Alternative zu Solarzellen aus Silizium. Allerdings weisen die organischen Materialien relativ schlechte Ladungstransporteigenschaften auf. Hybrid-Solarzellen, in denen Polymere mit geeigneten anorganischen Halbleitern kombiniert sind, besitzen einerseits die praktischen Vorteile der Organik und andererseits die hohe Elektronenbeweglichkeit der anorganischen Materialien. Wissenschaftler der Technischen Universität Eindhoven haben kürzlich Hybrid-Solarzellen vorgestellt, die aus einem halbleitenden Polymer mit Zinkoxid-Nanopartikeln bestehen.

  5. The GEM project: An international collaboration to survey galacticradiation emission

    SciTech Connect

    Torres, S.; Canon, V.; Casas, R.; Umana, A.; Tello, C.; Villela,T.; Bersanelli, M.; Bensadoun, M.; deAmici, G.; Limon, M.; Smoot, G.; Witebsky, C.

    1996-05-11

    The GEM (Galactic Emission Mapping) project is an international collaboration established with the aim of surveying the full sky at long wavelengths with a multi-frequency radio telescope. A total of 745 hours of observation at 408 MHz were completed from an Equatorial site in Colombia. The observations cover the celestial band O-h < alpha < 24(h), and -24 degrees 22 minutes < delta < +35 degrees 37 minutes. Preliminary results of this partial survey will be discussed. A review of the instrumental setup and a similar to 10 degrees resolution sky map at 408 MHz is presented.

  6. Reconstruction Software for High Multiplicity Events in GEM Detectors

    NASA Astrophysics Data System (ADS)

    Berretti, M.; Avati, V.; Bossini, E.; Brogi, P.; Brücken, E.; Giani, S.; Greco, V.; Lami, S.; Latino, G.; Oliveri, E.; Oljemark, F.; Österberg, K.; Scribano, A.; Turini, N.; Welti, J.

    2012-08-01

    We present a general description of the offline software developed for the reconstruction of inelastic events by the TOTEM T2 telescope at the LHC. Tracking reconstruction in the OMS forward region, where T2 is installed, is challenged by a large amount of charged particles generated by the interaction with the material placed between the IP and T2. In this contribution we describe the simulation of the T2 GEM chambers as well as the reconstruction procedures employed to track the particles in such severe environment. The strategy for the telescope alignment and the measurement of the charged particle pseudorapidity distribution is finally presented.

  7. Simulation of the GEM silicon central tracker using GEANT

    SciTech Connect

    Brooks, M.L.; Kinnison, W.W.

    1994-01-01

    The silicon central tracker of the GEM detector has been simulated using the high energy physics simulations code GEANT. This paper will describe the level of detail of the geometry of the tracker that is in the code, including the silicon detectors themselves as well as all non-sensitive volumes such as support structures; the digitization, or detector response to particles, of the silicon detectors; the coordinate reconstruction from the digitizations, and some of the results of the simulations regarding the detector performance.

  8. Overview of the Gems Model of Volunteer Administration (Generate, Educate, Mobilize and Sustain)

    ERIC Educational Resources Information Center

    Culp, Ken, III

    2012-01-01

    To organize and coordinate the efforts of many volunteers, a framework for volunteer engagement is needed. The "GEMS" Model of volunteer administration was developed to assist Extension professionals and volunteer coordinators to effectively administer volunteer programs without delivering the program themselves. The GEMS Model is…

  9. The GEMS X-Ray Polarimeter: Instrument Concept and Calibration Requirements

    NASA Technical Reports Server (NTRS)

    Jahoda, Keith

    2010-01-01

    The instrument and detector concepts for the Gravity and Extreme Magnetism Small Explorer (GEMS) X-ray polarimetry mission will be presente d. The calibration requirements for astrophysical X-ray polarimeters in general and GEMS in particular will be discussed.

  10. 16 CFR 23.25 - Misuse of the word “gem.”

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Misuse of the word âgem.â 23.25 Section 23.25 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.25 Misuse of the word “gem.” (a) It is unfair...

  11. 16 CFR 23.25 - Misuse of the word “gem.”

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Misuse of the word âgem.â 23.25 Section 23.25 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.25 Misuse of the word “gem.” (a) It is unfair...

  12. 16 CFR 23.25 - Misuse of the word “gem.”

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Misuse of the word âgem.â 23.25 Section 23.25 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.25 Misuse of the word “gem.” (a) It is unfair...

  13. 16 CFR 23.25 - Misuse of the word “gem.”

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Misuse of the word âgem.â 23.25 Section 23.25 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.25 Misuse of the word “gem.” (a) It is unfair...

  14. 16 CFR 23.25 - Misuse of the word “gem.”

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Misuse of the word âgem.â 23.25 Section 23.25 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.25 Misuse of the word “gem.” (a) It is unfair...

  15. GEM RUSSET: A LONG RUSSET POTATO VARIETY WITH EXCELLENT FRESH MARKET AND FRENCH FRY PROCESSING QUALITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gem Russet, a new medium maturing, long russet potato variety, was released in 2000 by the USDA/ARS and the experiment stations of Idaho, Oregon, and Washington. It is suited for use in the fresh, frozen-fried processing, and dehydration markets. Total tuber yield of Gem Russet is similar to that ...

  16. MIT 12 Tesla Coil test results

    NASA Astrophysics Data System (ADS)

    Steeves, M. M.; Hoenig, M. O.

    1985-07-01

    Test results from the MIT 12 Tesla Coil experiment are presented. The coil was tested in the High Field Test Facility (HFTF) of the Lawrence Livermore National Laboratory in October 1984 and January 1985. The experiment measured the performance of an Internally Cooled, Cabled Superconductor (ICCS) of practical size, intended for use in magnetic fusion experiments. The MIT coil carried 15 kA at 11 T for 5 min with no sign of instability. A half turn length in a 10 T field was able to absorb a heat load in 4 msec of more than 200 mJ sub cm of cable volume while carrying a current of 12 kA. The MIT coil successfully met the performance requirements of the Department of Energy's 12 Tesla Coil Program.

  17. Possible Gems and Ultra-Fine Grained Polyphase Units in Comet Wild 2.

    NASA Technical Reports Server (NTRS)

    Gainsforth, Z.; Butterworth, A. L.; Jilly-Rehak, C. E.; Westphal, A. J.; Brownlee, D. E.; Joswiak, D.; Ogliore, R. C.; Zolensky, M. E.; Bechtel, H. A.; Ebel, D. S.; Huss, G. R.; Sandford, S. A.; White, A. J.

    2016-01-01

    GEMS and ultrafine grained polyphase units (UFG-PU) in anhydrous IDPs are probably some of the most primitive materials in the solar system. UFG-PUs contain nanocrystalline silicates, oxides, metals and sulfides. GEMS are rounded approximately 100 nm across amorphous silicates containing embedded iron-nickel metal grains and sulfides. GEMS are one of the most abundant constituents in some anhydrous CPIDPs, often accounting for half the material or more. When NASA's Stardust mission returned with samples from comet Wild 2 in 2006, it was thought that UFG-PUs and GEMS would be among the most abundant materials found. However, possibly because of heating during the capture process in aerogel, neither GEMS nor UFG-PUs have been clearly found.

  18. PREFACE: Science's gem: diamond science 2009 Science's gem: diamond science 2009

    NASA Astrophysics Data System (ADS)

    Mainwood, Alison; Newton, Mark E.; Stoneham, Marshall

    2009-09-01

    Natural diamond has been valued for its appearance and mechanical properties for at least two thousand years. As a gem stone diamond is unsurpassed. However, scientific work, especially in the last 20 years, has demonstrated that diamond has numerous surprising properties and many unique ones. Some of the extreme properties have been known for many years, but the true scale of diamond's other highly desirable features is still only coming to light as control in the synthesis of diamond, and hence material perfection, improves. The ultimate prize for man-made diamond is surely not in the synthesis of gem stones, but in delivering technological solutions enabled by diamond to the challenges facing our society today. If the special properties are to be exploited to their full potential, at least four crucial factors must be considered. First, there must be sufficient scientific understanding of diamond to make applications effective, efficient and economical. Secondly, the means of fabrication and control of properties have to be achieved so that diamond's role can be optimised. Thirdly, it is not enough that its properties are superior to existing materials: they must be so much better that it is worth initiating new technologies to exploit them. Finally, any substantial applications will have to address the society's major needs worldwide. The clear technology drivers for the 21st century come from the biomedical technologies, the demand for energy subject to global constraints, and the information technologies, where perhaps diamond will provide the major enabling technology [1]. The papers in this volume concern the solid state physics of diamond, and primarily concern the first two factors: understanding, and control of properties. They address many of the outstanding basic problems, such as the identification of existing defects, which affect the material's properties, both desirable and less so. Regarding future substantial applications, one paper discusses

  19. Great Explorations in Math and Science[R] (GEMS[R]) Space Science. What Works Clearinghouse Intervention Report

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2012

    2012-01-01

    "Great Explorations in Math and Science[R] (GEMS[R]) Space Science" is an instructional sequence for grades 3-5 that covers fundamental concepts, including planetary sizes and distance, the Earth's shape and movement, gravity, and moon phases and eclipses. Part of the "GEMS"[R] core curriculum, "GEMS[R] Space Science" uses the solar system as the…

  20. Two-dimensional position sensitive ionization chamber with GEM

    NASA Astrophysics Data System (ADS)

    Kitamura, Noritaka; Noro, Tetsuo; Sakaguchi, Satoshi; Takao, Hideaki; Nishio, Yasutaka

    2014-09-01

    We have been developing a multi-anode ionization chamber for Accelerator Mass Spectrometry (AMS) at Kyushu University. Furthermore, we are planning to construct a neutron detector with high position resolution by combining the chamber with Gas Electron Multiplier (GEM) and a neutron converter. One of purposes is the measurement of p-> , pn knockout reaction from unstable nuclei. The multi-anode ionization chamber is composed of subdivided multiple anodes, a cathode to produce an uniform electric field, and a Frisch grid. The chamber must have position sensitivity because obtaining a beam profile is required for AMS measurements, where counting loss should be avoided. Also in the case of the neutron detector, it is necessary to measure the position to deduce the scattering angles. We have recently established a two-dimensional position readout system by the following methods: the measurement of horizontal position is enabled by trimming some anodes into wedge-like shape, and vertical position can be determined by the ratio of induced charge on the grid to the total charge on anodes. In addition, improvement of S/N ratio is important for isotope separation and position resolution. We installed a rectangular-shaped GEM and tried improving S/N ratio by electron amplification.

  1. Coordinated Chemical and Isotopic Studies of GEMS in IDPS

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Messenger, S.

    2008-01-01

    Cometary IDPs contain a record of the building blocks of the solar system including presolar grains, molecular cloud material, and materials formed in the early solar nebula [1]. Following their accretion, these materials have remained relatively unaltered because of the lack of parent body hydrothermal alteration. We are using coordinated transmission electron microscope (TEM) and ion microprobe studies to establish the origins of the various components within cometary IDPs. Of particular interest is the nature and abundance of presolar silicates in these IDPs because astronomical observations suggest that crystalline and amorphous silicates are the dominant grain types produced in young main sequence stars and evolved O-rich stars [e.g. 2]. Amorphous silicates (in the form of GEMS grains) are a major component of cometary IDPs and so a major objective of this work is to elucidate their origins. In rare cases, GEMS grains have highly anomalous O isotopic compositions that establish their origins as circumstellar condensates [3]. Here we present data on a systematic study of the silicate components within a primitive IDP.

  2. GEM-type detectors using LIGA and etchable glass technologies

    SciTech Connect

    Ahn, S.K.; Kim, J.G.; Perez-Mendez, V.; Chang, S.; Jackson, K.H.; Kadyk, J.A.; Wenzel, W.A.; Cho, G.

    2001-11-02

    Gas electron multipliers (GEMS) have been made by a deep X-ray lithography technique (LIGA process) using synchrotron radiation on polymethylmethacrylate (PMMA) and by UV processes using a UV etchable glass. Gain, stability and rate capability for these detectors are described.The LIGA detectors described consist of PMMA sheets of various thicknesses, 125mm to 350mm, and have 150mm x 150mm square holes spaced with a pitch of 300mm. Thin copper electrodes are plated on the top and bottom surfaces using a Damascene method, followed by electroless plating of the copper onto a palladium-tin base layer. For various thicknesses of PMMA measurements have been made of absolute gain vs. voltage, time stability of gain, and rate capability. The operating gas mixture was usually Ar/CO2 (70/30) gas, but some tests were also done using P10 gas. We also made GEM-like detectors using the UV etchable glass called Foturan, patterned by exposure to UV light and subsequent etching. A few measurements using these detectors will be reported, including avalanche gain and time stability.

  3. The stable K0 giant star β Gem

    SciTech Connect

    Gray, David F.

    2014-12-01

    A nine-season spectroscopic study of the photosphere of β Gem (K0 III) shows this low-luminosity giant to be stable, with no effective temperature variations above ∼2 K, and no secular temperature variations over the 2002-2010 time span above 0.2 K per year. The radial-velocity variations are consistent with an orbital variation of ∼40 m s{sup –1}. The projected rotation rate is found to be 1.70 ± 0.20 km s{sup –1} with a macroturbulence dispersion of 4.53 ± 0.10 km s{sup –1}. The third-signature plot is also invariant and shows a granulation velocity gradient 20% smaller than the solar gradient. The absolute shift of the third-signature plot gives a blueshift-corrected radial velocity of 3385 ± 70 m s{sup –1}. Bisector mapping of the Fe I λ6253 line yields a flux deficit of 12% ± 1% in area, somewhat smaller than for other giants, but the shape and the position of the peak at 4.8 km s{sup –1} is consistent with other giants. All of the investigated photospheric parameters are consistent with β Gem being a low-luminosity giant in agreement with its absolute magnitude.

  4. Measurements of GEM fluxes and atmospheric mercury concentrations (GEM, RGM and Hg p) from an agricultural field amended with biosolids in Southern Ont., Canada (October 2004-November 2004)

    NASA Astrophysics Data System (ADS)

    Cobbett, Frank D.; Van Heyst, Bill J.

    Five weeks of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particle bound mercury (Hg p) concentrations as well as fluxes of GEM were measured at Maryhill, Ontario, Canada above a biosolids amended field. The study occurred during the autumn of 2004 (October-November) to capture the effects of cool weather conditions on the behaviour of mercury in the atmosphere. The initial concentration of total mercury (Hg) in the amended soil was relatively low (0.4 μg g -1±10%). A micrometeorological approach was used to infer the flux of GEM using a continuous two-level sampling system with inlets at 0.40 and 1.25 m above the soil surface to measure the GEM concentration gradient. The required turbulent transfer coefficients were derived from meteorological parameters measured on site. The average GEM flux over the study was 0.1±0.2 ng m -2 h -1(±one standard deviation). The highest averaged hourly GEM fluxes occurred when the averaged net radiation was highest, although the slight diurnal patterns observed were not statistically significant for the complete flux data series. GEM emission fluxes responded to various local events including the passage of a cold front when the flux increased to 2 ng m -2 h -1 and during a biosolids application event at an adjacent field when depositional fluxes peaked at -3 ng m -2 h -1. Three substantial rain events during the study kept the surface soil moisture near field capacity and only slightly increased the GEM flux. Average concentrations of RGM (2.3±3.0 pg m -3), Hg p (3.0±6.2 pg m -3) and GEM (1.8±0.2 ng m -3) remained relatively constant throughout the study except when specific local events resulted in elevated concentrations. The application of biosolids to an adjacent field produced large increases in Hg p (25.8 pg m -3) and RGM (21.7 pg m -3) concentrations only when the wind aligned to impact the experimental equipment. Harvest events (corn) in adjacent fields also corresponded to higher

  5. Incentives in IT Yield Success at MIT.

    ERIC Educational Resources Information Center

    Hanson, Mary

    2001-01-01

    Describes the role of information technology (IT) at the Massachusetts Institute of Technology, explaining that attention to the unique characteristics of an MIT education and incentives for sustainable change are central to its IT efforts. Discusses various IT initiatives, such as Project Athena, provision on campus, international efforts, and…

  6. Erfahrungen mit den Pentax SDHF-Refraktoren.

    NASA Astrophysics Data System (ADS)

    de Lignie, J.

    1996-10-01

    Behandelt werden: die SDHF-Refraktoren, mechanische Eigenschaften und Verarbeitung, die Montierung MS-3n, Beobachtungen mit der SDHF-Optik und optische Qualität, der 75 SDHF, der 105 SDHF. Fotografischer Teil: die Pentax 645 als Astrokamera, fotografische Abbildung der Objektive zur Pentax 645 und der SDHF-Optik, Zubehör.

  7. Wrestling with Pedagogical Change: The TEAL Initiative at MIT

    ERIC Educational Resources Information Center

    Breslow, Lori

    2010-01-01

    In the late 1990s, the physics department at the Massachusetts Institute of Technology (MIT) had a problem. The department was responsible for teaching the two required physics courses that are part of the General Institute Requirements (GIRs), MIT's core curriculum--Physics I (mechanics, or in MIT parlance, 8.01) and Physics II (electricity and…

  8. Reactivity worth of gas expansion modules (GEMs) in the fast flux test facility

    SciTech Connect

    Campbell, L.R.; Nelson, J.V.; Burke, T.M.; Rawlins, J.A.; Daughtry, J.W.; Bennett, R.A.

    1986-01-01

    A new passive shutdown device called a gas expansion module (GEM) has been developed at Hanford Engineering Development Laboratory to insert negative reactivity during a primary system loss of flow in a liquid-metal reactor (LMR). A GEM is a hollow removable core component which is sealed at the top and open at the bottom. An argon gas bubble trapped inside the assembly expands when core inlet pressure decreases (caused by a flow reduction) and expels sodium from the assembly. The GEMs are designed so that the level of the liquid-sodium primary system coolant within a GEM is above the top of the core when the primary pumps are operating at full flow and is below the bottom of the core when the primary pumps are off. When a GEM is placed at the boundary of the core and radial reflector, the drop in sodium level increases core neutron leakage and inserts negative reactivity. The results of these measurements confirm the effectiveness of GEMs in adding negative reactivity in loss-of-flow situations. It follows, therefore, that the inherent safety of LMRs, comparable in size to the FFTF, can be enhanced by the use of GEMs.

  9. The conserved GTPase Gem1 regulates endoplasmic reticulum–mitochondria connections

    PubMed Central

    Kornmann, Benoît; Osman, Christof; Walter, Peter

    2011-01-01

    Mitochondria are connected to the endoplasmic reticulum (ER) through specialized protein complexes. We recently identified the ER–mitochondria encounter structure (ERMES) tethering complex, which plays a role in phospholipid exchange between the two organelles. ERMES also has been implicated in the coordination of mitochondrial protein import, mitochondrial DNA replication, and mitochondrial dynamics, suggesting that these interorganelle contact sites play central regulatory roles in coordinating various aspects of the physiology of the two organelles. Here we purified ERMES complexes and identified the Ca2+-binding Miro GTPase Gem1 as an integral component of ERMES. Gem1 regulates the number and size of the ERMES complexes. In vivo, association of Gem1 to ERMES required the first of Gem1’s two GTPase domains and the first of its two functional Ca2+-binding domains. In contrast, Gem1’s second GTPase domain was required for proper ERMES function in phospholipid exchange. Our results suggest that ERMES is not a passive conduit for interorganellar lipid exchange, but that it can be regulated in response to physiological needs. Furthermore, we provide evidence that the metazoan Gem1 ortholog Miro-1 localizes to sites of ER–mitochondrial contact, suggesting that some of the features ascribed to Gem1 may be evolutionarily conserved. PMID:21825164

  10. GEM, a member of the GRAM domain family of proteins, is part of the ABA signaling pathway

    PubMed Central

    Mauri, Nuria; Fernández-Marcos, María; Costas, Celina; Desvoyes, Bénédicte; Pichel, Antonio; Caro, Elena; Gutierrez, Crisanto

    2016-01-01

    Abscisic acid (ABA) is fundamental for plant development. Multiple factors have been identified that participate in the ABA signaling network, although a role of many proteins still await to be demonstrated. Here we have investigated the role of GEM (GL2 EXPRESSION MODULATOR), originally annotated as an ABA-responsive protein. GEM contains a GRAM domain, a feature shared with other eight Arabidopsis proteins for which we propose the name of GRE (GEM-RELATED) proteins. We found that (i) GEM expression responds to ABA, (ii) its promoter contains ABRE sites required for ABA response, and (iii) GEM expression depends on members of the ABA signaling pathway. This is consistent with the expression pattern of GEM during development in plant locations were ABA is known to play a direct role. We also found that GEM binds various phospholipids, e.g. mono and diphosphates and phosphatidic acid, suggesting a potential link of GEM with membrane-associated processes. Consistent with this, we found that the phosphoinositol-4-phosphate kinase PIP5K9 binds GEM in vivo. Finally, we demonstrated a role of GEM in seed dormancy. Together, our data led us to propose that GEM is an ABA-responsive protein that may function downstream of ABI5 as part of the ABA signaling pathway. PMID:26939893

  11. GEM, a member of the GRAM domain family of proteins, is part of the ABA signaling pathway.

    PubMed

    Mauri, Nuria; Fernández-Marcos, María; Costas, Celina; Desvoyes, Bénédicte; Pichel, Antonio; Caro, Elena; Gutierrez, Crisanto

    2016-01-01

    Abscisic acid (ABA) is fundamental for plant development. Multiple factors have been identified that participate in the ABA signaling network, although a role of many proteins still await to be demonstrated. Here we have investigated the role of GEM (GL2 EXPRESSION MODULATOR), originally annotated as an ABA-responsive protein. GEM contains a GRAM domain, a feature shared with other eight Arabidopsis proteins for which we propose the name of GRE (GEM-RELATED) proteins. We found that (i) GEM expression responds to ABA, (ii) its promoter contains ABRE sites required for ABA response, and (iii) GEM expression depends on members of the ABA signaling pathway. This is consistent with the expression pattern of GEM during development in plant locations were ABA is known to play a direct role. We also found that GEM binds various phospholipids, e.g. mono and diphosphates and phosphatidic acid, suggesting a potential link of GEM with membrane-associated processes. Consistent with this, we found that the phosphoinositol-4-phosphate kinase PIP5K9 binds GEM in vivo. Finally, we demonstrated a role of GEM in seed dormancy. Together, our data led us to propose that GEM is an ABA-responsive protein that may function downstream of ABI5 as part of the ABA signaling pathway. PMID:26939893

  12. Large size GEM for Super Bigbite Spectrometer (SBS) polarimeter for Hall A 12 GeV program at JLab

    NASA Astrophysics Data System (ADS)

    Gnanvo, Kondo; Liyanage, Nilanga; Nelyubin, Vladimir; Saenboonruang, Kiadtisak; Sacher, Seth; Wojtsekhowski, Bogdan

    2015-05-01

    We report on the R&D effort in the design and construction of a large size Gas Electron Multiplier (GEM) for the Proton Polarimeter Back Tracker (BT) of the Super Bigbite Spectrometer (SBS) in Hall A at Thomas Jefferson National Laboratory (JLab). The SBS BT GEM trackers consist of two sets of five large GEM chambers of size 60×200 cm2. The GEM chamber is a vertical stack of four GEM modules, each with an active area of 60×50 cm2. We have built and tested several prototypes and the construction of GEM modules for SBS BT is ongoing. We describe in this paper the design and construction of the GEM module prototype as well as the preliminary results on performance from tests carried out in our detector lab and during test beam at Fermi National Laboratory (Fermilab).

  13. Accuracy of the GEM-T2 geopotential from Geosat and ERS 1 crossover altimetry

    NASA Astrophysics Data System (ADS)

    Wagner, C. A.; Klokočník, J.

    1994-05-01

    Extensive analyses of altimetrically determined sea height differences at crossovers have been used to assess the accuracy of the GEM-T2 geopotential. The orbits used were determined with GEM-T2 for Geosat in its 17-day Exact Repeat Mission (ERM) in 1986-1989 and ERS 1 in both its 3-day ERM in 1991-1992 and its 35-day ERM in 1992. The data examined are completely independent of the data used in GEM-T2's development though GEM-T2 had considerable use of Doppler tracking information on Geosat. The test of the radial accuracy of the ERS 1 orbit (98.5° inclination) is especially significant because it is not ``close'' to any other orbit well represented in GEM-T2. The assessment consists of a comparison of observed mean height differences at thousands of distinct geographic locations with error projections from the GEM-T2 covariance matrix which was estimated from other data sources. This first comprehensive, independent test of the purely radial accuracy of an orbit-geopotential model clearly shows that the covariant predictions for GEM-T2 are broadly reliable for this purpose. Thus, the agreement of crossover predictions and observations suggests that the total radial errors for these ERMs, due to only to GEM-T2 (but excluding the effects of initial state error) are about 23 cm for Geosat and 115 cm (rms) for ERS 1. However, there is little detailed agreement of measurements and predictions for ERS 1 and only partial agreement in detail for Geosat. Our 30,000 mean crossover discrepancies for Geosat (derived from ERM cycles 1-44) are also shown to reduce substantially the crossover height differences in cycles 45-61, almost exactly as predicted if these are the true GEM-T2 errors for this orbit.

  14. Characterization of a scintillating GEM detector with low energy x-rays.

    PubMed

    Seravalli, E; de Boer, M R; Geurink, F; Huizenga, J; Kreuger, R; Schippers, J M; van Eijk, C W E

    2008-11-01

    A two-dimensional position-sensitive dosimetry system based on a scintillating gas detector is being developed with the aim of using it for pre-treatment verification of dose distributions in charged particle therapy. The dosimetry system consists of a chamber filled with an Ar/CF(4) scintillating gas mixture, inside which two cascaded gas electron multipliers (GEMs) are mounted. A GEM is a thin kapton foil with copper cladding structured with a regular pattern of sub-mm holes. In such a system, light quanta are emitted by the scintillating gas mixture during the electron avalanches in the GEM holes when radiation traverses the detector. The light intensity distribution is proportional to the energy deposited in the detector's sensitive volume by the beam. In the present work, we investigated the optimization of the scintillating GEM detector light yield. The light quanta are detected by means of a CCD camera or a photomultiplier tube coupled to a monochromator. The GEM charge signal is measured simultaneously. We have found that with 60 microm diameter double conical GEM holes, a brighter light signal and a higher electric signal are obtained than with 80 microm diameter holes. With an Ar + 8% CF(4) volume concentration, the highest voltage across the GEMs and the largest light and electric signals were reached. Moreover, we have found that the emission spectrum of Ar/CF(4) is independent of (1) the voltages applied across the GEMs, (2) the x-ray beam intensity and (3) the GEM hole diameter. On the other hand, the ratio of Ar to CF(4) peaks in the spectrum changes when the concentration of the latter gas is varied. PMID:18854612

  15. A spectrophotometric study of IR Gem at outburst and quiescence

    NASA Technical Reports Server (NTRS)

    Feinswog, Laurie; Szkody, Paula; Garnavich, Peter

    1988-01-01

    Optical spectra with 2.5-A resolution obtained throughout the orbit of IR Gem during a five-day sequence beginning at an outburst state and ending at quiescence are compared with B magnitude and IUE spectra obtained throughout other quiescent-state orbits. No obvious second component is found in the emission lines. In contrast to previous results, little high-excitation He II 4686-A emission is noted, and no variation of the equivalent widths of the Balmer emission is found over the orbital cycle. The results suggest that large changes in the excitation level and in the modulation from a heated zone can take place during different quiescent states, possibly due to the interoutburst phase.

  16. The RDT-RPC technology option of GEM

    SciTech Connect

    Not Available

    1993-01-29

    A muon system for the GEM SSCL detector based on Round Drift Tubes (RDT) has many attractive features. The Pt-trigger and beam crossing tag for the RDT tracking system can be accomplishment by either a PWC system, similar but less costly in design than Cathode Strip Chambers, or by a promising new type of RPC chamber. Given the economic construction of these chamber technologies a system can be envisioned with both good momentum reconstruction performance and pattern recognition capabilities. Full-scale chamber prototypes based on the RDT and RPC technologies have been constructed and tested successfully at the Texas Test Rig. Spatial resolutions have been measured in two designs of RDT chambers which meet or exceed the baseline resolution requirement of 100{mu}m per chamber layer.

  17. How Complete is the ISC-GEM Global Earthquake Catalog?

    NASA Astrophysics Data System (ADS)

    Michael, A. J.

    2013-12-01

    In January, 2013, the International Seismological Centre (ISC), in collaboration with the Global Earthquake Model (GEM) effort, released a new global earthquake catalog, covering the time period from 1900 through the end of 2009. The ISC-GEM catalog effort made substantial improvements over existing catalogs by adding new phase data, relocating all events using one method, and reviewing and revising magnitudes. In order to use this catalog for global earthquake studies, I determined the magnitude of completeness (Mc) as a function of time. First, I divided the catalog into 7 time periods based on major changes in catalog processing and data availability. For each time period, I used 4 objective methods to determine Mc, with uncertainties determined by non-parametric bootstrapping. Due to differences between the 4 methods, the final Mc was determined subjectively by examining the features that each method focused on in both the cumulative and binned magnitude frequency distributions (MFD). Features which were subjectively rejected as correct Mc determinations included complications in the MFD at high magnitudes well above a linear portion of the MFD, large curvature of the MFD at magnitudes below smaller curvatures, and changes in the MFD that were actually in an increase above a Gutenberg-Richter distribution with decreasing magnitude. The high end of the bootstrap confidence range was preferred so that there is 95% confidence that Mc is not underestimated. The time periods and Mc values are: 1900-1917, Mc=7.7; 1918-1939 Mc=6.8; 1940-1954, Mc=6.8; 1955-1963, Mc=6.5; 1964-1975, Mc=6.0; 1976-2003, Mc=5.8; and 2004-2009, Mc=5.7. Using these Mc values for the longest time periods they are valid for (e.g. 1918-2009, 1940-2009,...) the data fits a Gutenberg-Richter relationship with b=1.0 and a=8.3, within 1 std. dev, with no declustering. The exception is for time periods that include 1900-1917 in which there are only 28 events with M≥Mc and the largest event is only

  18. Performance simulation studies for the ALICE TPC GEM upgrade

    NASA Astrophysics Data System (ADS)

    Ljunggren, M.

    2016-07-01

    To be able to exploit the anticipated interaction rate of 50 kHz in Pb-Pb collisions during run 3 of the LHC (beyond 2019), the ALICE TPC will be upgraded to allow continuous readout. As this is not possible with the current Multi Wire Proportional Chamber (MWPC) based amplification, the readout will be replaced with Gas Electron Multiplier (GEM) readout chambers that can suppress ~ 99% of the ion back flow. The space charge of the remaining 1% ion back flow, however, will cause significant distortions to the measured tracks of order cm. Simulation studies to characterize the distortions and test correction strategies have been performed, which show that the intrinsic momentum resolution, without these distortions, can be recovered.

  19. Gem-quality Turkish purple jade: Geological and mineralogical characteristics

    NASA Astrophysics Data System (ADS)

    Hatipoğlu, Murat; Başevirgen, Yasemin; Chamberlain, Steven C.

    2012-02-01

    In the Harmancık-Bursa region of the western Anatolia (Turkey), an extensive contact metamorphic aureole at the border between the Late Mesozoic coherent metaclastic rocks of blueschist facies and the Early Senozoic intrusive granodiorite stock hosts an interesting and unique gem material with a mineral assemblage consisting mainly of jadeite, quartz, orthoclase, epidote, chloritoid, and phlogopite as identified by X-ray diffraction spectroscopy and polarized-light microscopy. In addition, chemical analyses performed with X-ray fluorescence and inductive-coupled plasma-atomic emission spectroscopy show that the mass of the metamorphic aureole has a silica-rich, calc-alkaline chemical content. Therefore, some rock building elements (such as Al, Ca, Na, K, P, Sr, and B of which characterize an acidic-neutral rock formation) and trace elements (such as Fe, Cr, Mn, Be, Cu, Ga, La, Ni, Pb, and Zn) are remarkable high ratios. Pale purple-colored gem material of this composition appears to be unique to Turkey, also is only found in one narrow provenance in Turkey. Therefore, it is specially called "Turkish (and/or Anatolian) purple jade" on the worldwide gem market. Even though the mineral jadeite is the principal constituent, 40% by volume as determined with petrographic thin-section examination under a polarized-light microscope, the material cannot be considered pure jadeite. Specific gravity measurements of the jade using a hydrostatic balance confirm that it has a heterogeneous structure. The measured average specific gravity of 3.04, is significantly lower than the normal range for characterized jadeites of 3.24-3.43. Turkish purple jade samples were examined in detail using dispersive confocal micro-Raman spectroscopy (DCμRS) as well as other well-known analytical methods. The resulting strong micro-Raman bands that peaked at 1038, 984, 697, 571, 521, 464, 430, 372, 326, 307, 264, and 201 cm -1 are characteristics of the Turkish purple jade. The first most

  20. Particle tracking with a Timepix based triple GEM detector

    NASA Astrophysics Data System (ADS)

    George, S. P.; Murtas, F.; Alozy, J.; Curioni, A.; Rosenfeld, A. B.; Silari, M.

    2015-11-01

    This paper details the response of a triple GEM detector with a 55 μmetre pitch pixelated ASIC for readout. The detector is operated as a micro TPC with 9.5 cm3 sensitive volume and characterized with a mixed beam of 120 GeV protons and positive pions. A process for reconstruction of incident particle tracks from individual ionization clusters is described and scans of the gain and drift fields are performed. The angular resolution of the measured tracks is characterized. Also, the readout was operated in a mixed mode where some pixels measure drift time and others charge. This was used to measure the energy deposition in the detector and the charge cloud size as a function of interaction depth. The future uses of the device, including in microdosimetry are discussed.

  1. Characteristics of a glass gem with a guard-ring structure

    NASA Astrophysics Data System (ADS)

    Mitsuya, Y.; Fujiwara, T.; Takahashi, H.

    2013-11-01

    We recently developed a Glass GEM (G-GEM), and it exhibited a superior performance compared with other gaseous detectors. We are currently developing a G-GEM with a single-sided guard ring structure, in order to improve its spark tolerance. In this research, we compared its performance with that of a conventional hole structure. The single-sided guard-ring structure has shown strong polarity when it was operated upside down, however, the similar output pulse shapes were observed for both cases. The gain curves were consistent with simulation results. The energy resolutions were also compared.

  2. Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains

    PubMed Central

    El Dine, Assaad Nasr; Khalaf, Ali; Grée, Danielle; Tasseau, Olivier; Fares, Fares; Jaber, Nada; Lesot, Philippe

    2013-01-01

    Summary Starting from easily accessible gem-difluoropropargylic derivatives, a DBU-mediated isomerisation affords enones in fair yields with a gem-difluoroalkyl chain. These derivatives were used to prepare pyrazolines and pyrrolines with the desired gem-difluoroalkyl side chain by cyclocondensations in good yields and with excellent stereoselectivity. A one-pot process was also successfully developed for these sequential reactions. By carrying out various types of Pd-catalyzed coupling reactions for compounds with a p-bromophenyl substituent a route to focused chemical libraries was demonstrated. PMID:24204405

  3. Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains.

    PubMed

    El Dine, Assaad Nasr; Khalaf, Ali; Grée, Danielle; Tasseau, Olivier; Fares, Fares; Jaber, Nada; Lesot, Philippe; Hachem, Ali; Grée, René

    2013-01-01

    Starting from easily accessible gem-difluoropropargylic derivatives, a DBU-mediated isomerisation affords enones in fair yields with a gem-difluoroalkyl chain. These derivatives were used to prepare pyrazolines and pyrrolines with the desired gem-difluoroalkyl side chain by cyclocondensations in good yields and with excellent stereoselectivity. A one-pot process was also successfully developed for these sequential reactions. By carrying out various types of Pd-catalyzed coupling reactions for compounds with a p-bromophenyl substituent a route to focused chemical libraries was demonstrated. PMID:24204405

  4. Editorial: Reviewer selection process and new areas of expertise in GEMS

    NASA Astrophysics Data System (ADS)

    Liemohn, Michael W.; Balikhin, Michael; Kepko, Larry; Rodger, Alan; Wang, Yuming

    2016-06-01

    One method of selecting potential reviewers for papers submitted to the Journal of Geophysical Research Space Physics is to filter the user database within the Geophysical Electronic Manuscript System (GEMS) by areas of expertise. The list of these areas in GEMS can be self selected by users in their profile settings. The Editors have added 18 new entries to this list, an increase of 33% more than the previous 55 entries. All space physicists are strongly encouraged to update their profile settings in GEMS, especially their areas of expertise selections, and details of how to do this are provided.

  5. Characterization of a GEM-based fast neutron detector

    NASA Astrophysics Data System (ADS)

    Esposito, B.; Marocco, D.; Villari, R.; Murtas, F.; Rodionov, R.

    2014-03-01

    The neutron efficiency of a Gas Electron Multiplier (GEM)-based detector designed for fast neutron measurements in fusion devices was determined through the combined use of Monte Carlo (MCNPX) calculations and analysis of deuterium-deuterium and deuterium-tritium neutron irradiation experiments. The detector, characterized by a triple GEM structure flushed with a Ar/CO2/CF4 - 45/15/40 gas mixture, features a digital read-out system and has two sub-units for the detection of 2.5+14 MeV neutrons and 14 MeV neutrons (UDD and UDT, respectively). The pulse height spectra (PHS) determined from the curves of experimental efficiency as a function of the detector's high voltage (HV) and the MCNPX-simulated PHS were compared using a fitting routine that finds the best match between the experimental and simulated PHS by assuming a parametric model for the relation between HV (that determines the detector's gain) and the energy deposited in the gas. This led to express the experimental neutron efficiency as a function of the discrimination level set on the deposited energy (energy threshold). The detector sensitivity to γ-rays was also analyzed and the operational range in which the γ-ray contribution to the signal is not negligible was determined. It is found that this detector can reach a maximum neutron efficiency of ~1×10-3 counts/n at 2.5 MeV (UDD sub-unit) and of ~4×10-3 counts/n at 14 MeV (UDT and UDD sub-units).

  6. GEMS and New Pre-Accretionally Irradiated RELICT Grains in Interplanetary Dust - The Plot Thickens

    NASA Astrophysics Data System (ADS)

    Bradley, J.

    1995-09-01

    The hypothesis that GEMS (glass with embedded metal and sulfides) in interplanetary dust particles (IDPs) might be the long-sought interstellar silicate grains is undergoing close scrutiny [1-3]. GEMS are proposed to be interstellar because: (a) they are abundant in cometary IDPs; (b) they were irradiated prior to incorporation into IDPs; (c) both their size distribution and Oamorphous silicate" microstructures are consistent with those of interstellar silicates; (d) they contain nanometer-sized (superparamagnetic) alpha-iron inclusions, which provides a simple explanation for the observed interstellar grain alignment and polarization [4,5]. Challenges to the GEMS hypothesis include the following: (a) GEMS may have formed and been irradiated in the solar nebula rather than a presolar interstellar environment; (b) non-solar isotope abundances have yet to be measured in GEMS; (c) the irradiation regime required to produce the observed effects in GEMS might be incompatible with the interstellar medium; (b) relationships between GEMS and carbon (e.g. core/mantle) need clarification; (c) major element abundances in GEMS should be consistent with observed interstellar gas phase depletions [2,3]. GEMS may indeed have formed in the solar nebula, in which case they would be the oldest known solar nebula solids [2]. An interstellar origin for GEMS does not require detection of non-solar isotope abundances [6]. Irradiation experiments are in progress to simulate the properties of GEMS. The petrographic relationship between GEMS and carbon in IDPs is being investigated (by examining IDPs embedded and thin-sectioned in carbon-free media). Major element abundances in GEMS are being evaluated in terms on interstellar gas phase abundances. For example, sulfur is not highly depleted in the interstellar gas, implying that it must be significantly depleted in interstellar grains [3]. GEMS are significantly depleted in sulfur relative to solar abundances. Analytical electron

  7. Flight research with the MIT Daedalus prototype

    NASA Technical Reports Server (NTRS)

    Bussolari, Steven R.; Youngren, Harold H.; Langford, John S.

    1987-01-01

    The MIT Light Eagle human-powered aircraft underwent long-duration testing over Rogers Dry Lake in California during January, 1987. Designed as a prototype for the MIT Daedalus Project, the Light Eagle's forty-eight flights provided pilot training, established new distance records for human-powered flight, and provided quantitative data through a series of instrumented flight experiments. The experiments focused on: (1) evaluating physiological loads on the pilot, (2) determining airframe power requirements, and (3) developing an electronic flight control system. This paper discusses the flight test program, its results and their implications for the follow-on Daedalus aircraft, and the potential uses of the Light Eagle as a low Reynolds number testbed.

  8. Development of the GEM-MSTPC for studies of astrophysical nuclear reaction rates

    SciTech Connect

    Yamaguchi, K.; Arai, I.; Ishiyama, H.; Watanabe, Y. X.; Tanaka, M. H.; Miyatake, H.; Hirayama, Y.; Imai, N.; Fuchi, Y.; Jeong, S. C.; Nomura, T.; Mizoi, Y.; Das, S. K.; Fukuda, T.; Hashimoto, T.; Yamaguchi, H.; Kubono, S.; Hayakawa, S.; Makii, H.; Mitsuoka, S.

    2010-08-12

    We have developed an active-target type gas-detector, a Gas Electron Multiplier Multiple-Sampling and Tracking Proportional Chamber (GEM-MSTPC) operating with low-pressure He-base mixed gas, where He is used as a target for studies of astrophysical nuclear reaction rates. Different kinds of 400 {mu}m thick GEMs were examined. The gain stability was examined with a configuration of GEMs of 400 {mu}m in thickness fabricated in different ways, against the injection rate of low-energy heavy ions of 10{sup 5} particles per second. The gain of GEM with Cu electrodes coated by Au was observed to be stable up to the injection rate of 10{sup 5} particles per second.

  9. Gain Characteristics of a 100 μm thick Gas Electron Multiplier (GEM)

    NASA Astrophysics Data System (ADS)

    Mir, J. A.; Natal da Luz, H.; Carvalho, X.; Azevedo, C. D. R.; dos Santos, J. M. F.; Amaro, F. D.

    2015-12-01

    The standard Gas Electron Multiplier (GEM) invented by F. Sauli [1] consists of high density holes etched in 50 μm thick copper clad Kapton foil. This study, however, investigated the basic charge gain characteristics of a non-standard 100 μm thick Gas Electron Multiplier, fabricated using the same wet chemical etch process at CERN. It was possible to sustain charge gains of 3× 103 and 1× 104 using single and double stage configurations, respectively, operated in an Ar(70%)-CO2(30%) gas mixture. These values are similar to those achieved with standard GEMs. Crucially, we found that the thicker GEM is more robust as it withstood sparking without catastrophic failure. We also measured the gain dependence on ambient variables such as pressure and temperature and found the gain sensitivity to be 4.0 K/mbar, compared with 1.55 K/mbar for the standard GEM.

  10. Upgrade of the CMS muon system with triple-GEM detectors

    NASA Astrophysics Data System (ADS)

    Abbaneo, D.; Abbas, M.; Abbrescia, M.; Abdelalim, A. A.; Abi Akl, M.; Ahmed, W.; Ahmed, W.; Altieri, P.; Aly, R.; Ashfaq, A.; Aspell, P.; Assran, Y.; Awan, I.; Bally, S.; Ban, Y.; Banerjee, S.; Barria, P.; Benussi, L.; Bhopatkar, V.; Bianco, S.; Bos, J.; Bouhali, O.; Braibant, S.; Buontempo, S.; Cai, J.; Calabria, C.; Caputo, C.; Cassese, F.; Castaneda, A.; Cauwenbergh, S.; Cavallo, F. R.; Celik, A.; Choi, M.; Choi, K.; Choi, S.; Christiansen, J.; Cimmino, A.; Colafranceschi, S.; Colaleo, A.; Conde Garcia, A.; Dabrowski, M. M.; De Lentdecker, G.; De Oliveira, R.; de Robertis, G.; Dildick, S.; Dorney, B.; Elmetenawee, W.; Fabrice, G.; Ferry, S.; Giacomelli, P.; Gilmore, J.; Guiducci, L.; Gutierrez, A.; Hadjiiska, R. M.; Hassan, A.; Hauser, J.; Hoepfner, K.; Hohlmann, M.; Hoorani, H.; Jeng, Y. G.; Kamon, T.; Karchin, P. E.; Kim, H.; Krutelyov, S.; Kumar, A.; Lee, J.; Lee, J.; Lenzi, T.; Litov, L.; Loddo, F.; Maerschalk, T.; Magazzu, G.; Maggi, M.; Maghrbi, Y.; Magnani, A.; Majumdar, N.; Mal, P. K.; Mandal, K.; Marchioro, A.; Marinov, A.; Merlin, J. A.; Mohammed, N.; Mohanty, A. K.; Mohapatra, A.; Muhammad, S.; Mukhopadhyay, S.; Nuzzo, S.; Oliveri, E.; Pant, L. M.; Paolucci, P.; Park, I.; Passeggio, G.; Pavlov, B.; Philipps, B.; Phipps, M.; Piccolo, D.; Postema, H.; Pugliese, G.; Baranac, A. Puig; Radi, A.; Radogna, R.; Raffone, G.; Ramkrishna, S.; Ranieri, A.; Riccardi, C.; Rodrigues, A.; Ropelewski, L.; Roychoddhury, S.; Ryu, M. S.; Ryu, G.; Safonov, A.; Sakharov, A.; Salva, S.; Saviano, G.; Sharma, A.; Swain, S. K.; Talvitie, J. P.; Tamma, C.; Tatarinov, A.; Turini, N.; Tuuva, T.; Twigger, J.; Tytgat, M.; Vai, I.; van Stenis, M.; Venditi, R.; Verhagen, E.; Verwilligen, P.; Vitulo, P.; Yang, U.; Yang, Y.; Yonamine, R.; Zaganidis, N.; Zenoni, F.; Zhang, A.

    2014-10-01

    The CMS collaboration considers upgrading the muon forward region which is particularly affected by the high-luminosity conditions at the LHC. The proposal involves Gas Electron Multiplier (GEM) chambers, which are able to handle the extreme particle rates expected in this region along with a high spatial resolution. This allows to combine tracking and triggering capabilities, which will improve the CMS muon High Level Trigger, the muon identification and the track reconstruction. Intense R&D has been going on since 2009 and it has lead to the development of several GEM prototypes and associated detector electronics. These GEM prototypes have been subjected to extensive tests in the laboratory and in test beams at the CERN Super Proton Synchrotron (SPS). This contribution will review the status of the CMS upgrade project with GEMs and its impact on the CMS performance.

  11. The gain in Thick GEM multipliers and its time-evolution

    NASA Astrophysics Data System (ADS)

    Alexeev, M.; Birsa, R.; Bradamante, F.; Bressan, A.; Büchele, M.; Chiosso, M.; Ciliberti, P.; Dalla Torre, S.; Dasgupta, S.; Denisov, O.; Duic, V.; Finger, M.; Finger, M., Jr.; Fischer, H.; Gobbo, B.; Gregori, M.; Herrmann, F.; Königsmann, K.; Levorato, S.; Maggiora, A.; Makke, N.; Martin, A.; Menon, G.; Novakova, K.; Novy, J.; Panzieri, D.; Pereira, F. A.; Santos, C. A.; Sbrizzai, G.; Schiavon, P.; Schopferer, S.; Slunecka, M.; Sozzi, F.; Steiger, L.; Sulc, M.; Takekawa, S.; Tessarotto, F.; Veloso, J. F. C. A.

    2015-03-01

    In the context of a project to upgrade the gas photon detectors of COMPASS RICH-1, we have performed an R&D programme aimed to develop photon detectors based on multi-layer arrangements of thick GEM electron multipliers coupled to a CsI photoconverter. For this purpose, thick GEMs have been characterised in detail including the gain performance, its dependance on the geometrical parameters and its time-evolution, a feature exhibited by the gas detectors with open insulator surfaces. The variation due to this evolution drammatically depends on the parameters themselves. In the present article we summarise the outcomes of the studies dedicated to the thick GEM gain and its evolution versus time. We also include a qualitative model which accounts for the peculiar details of the observed thick GEM gain time-evolution.

  12. Discriminating cosmic muons and X-rays based on rise time using a GEM detector

    NASA Astrophysics Data System (ADS)

    Wu, Hui-Yin; Zhao, Sheng-Ying; Wang, Xiao-Dong; Zhang, Xian-Ming; Qi, Hui-Rong; Zhang, Wei; Wu, Ke-Yan; Hu, Bi-Tao; Zhang, Yi

    2016-08-01

    Gas electron multiplier (GEM) detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and a method of discriminating between cosmic muons and X-rays based on rise time is tested. The energy resolution of the GEM detector is tested by 55Fe ray source to prove the GEM detector has a good performance. Analysis of the complete signal-cycles allows us to get the rise time and pulse heights. The experiment result indicates that cosmic muons and X-rays can be discriminated with an appropriate rise time threshold. Supported by National Natural Science Foundation of China (11135002, 11275235, 11405077, 11575073)

  13. Interpreting the Global Enteric Multicenter Study (GEMS) Findings on Sanitation, Hygiene, and Diarrhea.

    PubMed

    Crocker, Jonny; Bartram, Jamie

    2016-05-01

    In this Perspective on the GEMS study by Kelly Baker and colleagues, Jonny Crocker and Jamie Bartram consider the implications of associations found and not found between diarrheal disease and sanitation and hygiene. PMID:27138924

  14. Thermal neutron response of a boron-coated GEM detector via GEANT4 Monte Carlo code.

    PubMed

    Jamil, M; Rhee, J T; Kim, H G; Ahmad, Farzana; Jeon, Y J

    2014-10-22

    In this work, we report the design configuration and the performance of the hybrid Gas Electron Multiplier (GEM) detector. In order to make the detector sensitive to thermal neutrons, the forward electrode of the GEM has been coated with the enriched boron-10 material, which works as a neutron converter. A total of 5×5cm(2) configuration of GEM has been used for thermal neutron studies. The response of the detector has been estimated via using GEANT4 MC code with two different physics lists. Using the QGSP_BIC_HP physics list, the neutron detection efficiency was determined to be about 3%, while with QGSP_BERT_HP physics list the efficiency was around 2.5%, at the incident thermal neutron energies of 25meV. The higher response of the detector proves that GEM-coated with boron converter improves the efficiency for thermal neutrons detection. PMID:25464183

  15. eGEMs: Pragmatic Publishing to Build a Learning Health System.

    PubMed

    Holve, Erin

    2013-01-01

    The Electronic Data Methods (EDM) Forum announces the launch of eGEMs (Generating Evidence and Methods to improve patient outcomes), a new, free, open access, peer-reviewed e-publication. eGEMs aims to disseminate innovative ideas about how electronic clinical data (ECD) can be leveraged in comparative effectiveness research (CER), patient-centered outcomes research (PCOR) and quality improvement (QI). eGEMs seeks submissions in four main topic areas: analytic methods, clinical informatics, governance, and the learning health system. The goal of eGEMs is ultimately to promote dialogue and the sharing of ideas between researchers and other stakeholders in a credible and timely way, extending the efforts of the EDM Forum. PMID:25848553

  16. eGEMs: Pragmatic Publishing to Build a Learning Health System

    PubMed Central

    Holve, Erin

    2013-01-01

    The Electronic Data Methods (EDM) Forum announces the launch of eGEMs (Generating Evidence and Methods to improve patient outcomes), a new, free, open access, peer-reviewed e-publication. eGEMs aims to disseminate innovative ideas about how electronic clinical data (ECD) can be leveraged in comparative effectiveness research (CER), patient-centered outcomes research (PCOR) and quality improvement (QI). eGEMs seeks submissions in four main topic areas: analytic methods, clinical informatics, governance, and the learning health system. The goal of eGEMs is ultimately to promote dialogue and the sharing of ideas between researchers and other stakeholders in a credible and timely way, extending the efforts of the EDM Forum. PMID:25848553

  17. Grundlegende Steuerungsverfahren im heterogenen Logistiknetz mit Kanban

    NASA Astrophysics Data System (ADS)

    Dickmann, Eva; Dickmann, Philipp; Lödding, Hermann; Möller, Niklas; Rücker, Thomas; Schneider, Herfried M.; Zäh, Michael F.

    In vielen Unternehmen werden heterogene (verschiedene) Steuerungen in einem abgestimmten Konzept kombiniert. Je nach Anwendungsfall und Rahmenbedingungen werden Kombinationen allgemein bekannter Steuerungen oder Steuerungsvarianten gemischt eingesetzt, um eine optimale Steuerung für unterschiedliche Fälle zu erreichen. Hierbei stehen neben den bekannten und weit verbreiteten Methoden, wie Material Requirements Planning (MRP) oder Kanban, auch weniger bekannte oder neue Methoden zur Auswahl, wie die Produktionssteuerung mit dezentraler, bestandsorientierter Fertigungsregelung (DBF). Kanban ist ein simples und effizientes Steuerungskonzept, das in der klassischen Form für spezifische einfache Anwendungsfälle umsetzbar ist. Hochentwickelte Steuerungsalgorithmen können helfen, komplexe Abläufe optimal abzubilden. Mit einer grundlegenden Vereinfachung der Abläufe kann allerdings in vielen Fällen ein wesentlich stärkerer und umfassender Verbesserungseffekt erzielt werden. Die wesentliche Fragestellung sollte folglich lauten: Warum ist der Ablauf nicht mit einer einfachen Steuerung wie Kanban abzubilden? Um die Vorteile des Konzepts auch in untypischen Bereichen anwenden zu können, sind jedoch verschiedene Varianten oder Kanban-ähnliche Steuerungsmethoden entstanden. Darüber hinaus sind in der Praxis hybride Steuerungen im Einsatz, welche so kombiniert werden, dass die Zusammensetzung anspruchsvolle Eigenschaftsbilder noch exakt abbildet. In der Praxis basieren die Steuerungsentscheidungen nur zu einem kleinen Teil auf den eigentlichen Steuerungsalgorithmen, wie sie uns das MRP-System zur Verfügung stellt. Moderne Steuerungswelten" schließen alle relevanten Informationsquellen in eine heterogene Entscheidungsmatrix mit ein. Letztlich zählt nicht, ob die Entscheidung auf den Informationen aus dem MRP-System oder auf Softfacts basierend getroffen wurde, sondern nur, ob die Entscheidung erfolgreich war.

  18. Gem GTPase acts upstream Gmip/RhoA to regulate cortical actin remodeling and spindle positioning during early mitosis.

    PubMed

    Andrieu, Guillaume; Quaranta, Muriel; Leprince, Corinne; Cuvillier, Olivier; Hatzoglou, Anastassia

    2014-11-01

    Gem is a small guanosine triphosphate (GTP)-binding protein within the Ras superfamily, involved in the regulation of voltage-gated calcium channel activity and cytoskeleton reorganization. Gem overexpression leads to stress fiber disruption, actin and cell shape remodeling and neurite elongation in interphase cells. In this study, we show that Gem plays a crucial role in the regulation of cortical actin cytoskeleton that undergoes active remodeling during mitosis. Ectopic expression of Gem leads to cortical actin disruption and spindle mispositioning during metaphase. The regulation of spindle positioning by Gem involves its downstream effector Gmip. Knockdown of Gmip rescued Gem-induced spindle phenotype, although both Gem and Gmip accumulated at the cell cortex. In addition, we implicated RhoA GTPase as an important effector of Gem/Gmip signaling. Inactivation of RhoA by overexpressing dominant-negative mutant prevented normal spindle positioning. Introduction of active RhoA rescued the actin and spindle positioning defects caused by Gem or Gmip overexpression. These findings demonstrate a new role of Gem/Gmip/RhoA signaling in cortical actin regulation during early mitotic stages. PMID:25173885

  19. Mishap Investigation Team (MIT) - Barksdale AFB, Louisiana

    NASA Technical Reports Server (NTRS)

    Stepaniak, Philip

    2005-01-01

    The Shuttle Program is organized to support a Shuttle mishap using the resources of the MIT. The afternoon of Feb. 1, 2003, the MIT deployed to Barksdale AFB. This location became the investigative center and interim storage location for crewmembers received from the Lufkin Disaster Field Office (DFO). Working under the leadership of the MIT Lead, the medical team executed a short-term plan that included search, recovery, and identification including coordination with the Armed Forces Institute of Pathology Temporary operations was set up at Barksdale Air Force Base for two weeks. During this time, coordination with the DFO field recovery teams, AFIP personnel, and the crew surgeons was on going. In addition, the crewmember families and NASA management were updated daily. The medical team also dealt with public reports and questions concerning biological and chemical hazards, which were coordinated with SPACEHAB, Inc., Kennedy Space Center (KSC) Medical Operations and the Johnson Space Center (JSC) Space Medicine office. After operations at Barksdale were concluded the medical team transitioned back to Houston and a long-term search, recovery and identification plan was developed.

  20. Public release of the ISC-GEM Global Instrumental Earthquake Catalogue (1900-2009)

    USGS Publications Warehouse

    Storchak, Dmitry A.; Di Giacomo, Domenico; Bondára, István; Engdahl, E. Robert; Harris, James; Lee, William H.K.; Villaseñor, Antonio; Bormann, Peter

    2013-01-01

    The International Seismological Centre–Global Earthquake Model (ISC–GEM) Global Instrumental Earthquake Catalogue (1900–2009) is the result of a special effort to substantially extend and improve currently existing global catalogs to serve the requirements of specific user groups who assess and model seismic hazard and risk. The data from the ISC–GEM Catalogue would be used worldwide yet will prove absolutely essential in those regions where a high seismicity level strongly correlates with a high population density.

  1. Development of GEM-Based Digital Hadron Calorimetry Using the SLAC KPiX Chip

    SciTech Connect

    White, A.; /Texas U., Arlington /Washington U., Seattle /Unlisted /SLAC

    2012-04-12

    The development of Digital Hadron Calorimetry for the SiD detector Concept for the International Linear Collider is described. The jet energy requirements of the ILC physics program are discussed. The concept of GEM-based digital hadron calorimetry is presented, followed by a description of, and results from, prototype detectors. Plans are described for the construction of 1m{sup 2} GEM-DHCAL planes to be tested as part of a future calorimeter stack.

  2. Geostationary Environment Monitoring Spectrometer (gems) Over the Korea Peninsula and Asia-Pacific Region

    NASA Astrophysics Data System (ADS)

    Lasnik, J.; Stephens, M.; Baker, B.; Randall, C.; Ko, D. H.; Kim, S.; Kim, Y.; Lee, E. S.; Chang, S.; Park, J. M.; SEO, S. B.; Youk, Y.; Kong, J. P.; Lee, D.; Lee, S. H.; Kim, J.

    2014-12-01

    Introduction: The Geostationary Environment Monitoring Spectrometer (GEMS) is one of two instruments manifested aboard the South Korean Geostationary Earth Orbit KOrea Multi-Purpose SATellite-2B (GEO-KOMPSAT-2B or GK2B), which is scheduled to launch in 2018. Jointly developed/built by KARI and Ball Aerospace, GEMS is a geostationary UV-Vis hyperspectral imager designed to monitor trans-boundary tropospheric pollution events over the Korean peninsula and Asia-Pacific region. The spectrometer provides high temporal and spatial resolution (3.5 km N/S by 7.2 km E/W) measurements of ozone, its precursors, and aerosols. Over the short-term, hourly measurements by GEMS will improve early warnings for potentially dangerous pollution events and monitor population exposure. Over the 10-year mission-life, GEMS will serve to enhance our understanding of long-term climate change and broader air quality issues on both a regional and global scale. The GEMS sensor design and performance are discussed, which includes an overview of measurement capabilities and the on-orbit concept of operations. GEMS Sensor Overview: The GEMS hyperspectral imaging system consists of a telescope and Offner grating spectrometer that feeds a single CCD detector array. A spectral range of 300-500 nm and sampling of 0.2 nm enables NO2, SO2, HCHO, O3, and aerosol retrieval. The GEMS field of regard (FOR), which extends from 5°S to 45°N in latitude and 75°E to 145°E in longitude, is operationally achieved using an onboard two-axis scan mirror. On-orbit, the radiometric calibration is maintained using solar measurements, which are performed using two onboard diffusers: a working diffuser that is deployed routinely for the purpose of solar calibration, and a reference diffuser that is deployed sparingly for the purpose of monitoring working diffuser performance degradation.

  3. BoNuS: Development and Use of a Radial TPC using Cylindrical GEMs

    SciTech Connect

    Howard Fenker; Nathan Baillie; Peter Bradshaw; S. Bultmann; Stephen Bueltmann; Volker Burkert; Michael Christy; Gail Dodge; Dipangkar Dutta; Rolf Ent; Josh Evans; Robert Fersch; Kevin Giovanetti; Keith Griffioen; Mikayel Ispiryan; Chandana Jayalath; Narbe Kalantarians; Cynthia Keppel; Sebastian Kuhn; Gabriel Niculescu; Maria-Ioana Niculescu; Svyatoslav Tkachenko; Vladas Tvaskis; Jixie Zhang

    2007-11-28

    To provide new access to information about nucleon structure from electron-neutron interactions, a specialized aystem of target and detector was developed at Jefferson Lab. It allows identification and measurement of spectator protons produced in e X scattering events. The detector is a radial time-projection chamber optimized for the acceptance of low-momentum protons. Gas gain is provided by three cascaded curved Gas Electron Multipliers (GEMs), the first application of GEMs in any configuration other than flat.

  4. Systematic measurements of the gain and the energy resolution of single and double mask GEM detectors

    NASA Astrophysics Data System (ADS)

    Biswas, S.; Schmidt, D. J.; Abuhoza, A.; Frankenfeld, U.; Garabatos, C.; Hehner, J.; Kleipa, V.; Morhardt, T.; Schmidt, C. J.; Schmidt, H. R.; Wiechula, J.

    2016-07-01

    Systematic studies on the gain and the energy resolution have been carried out by varying the voltage across the GEM foils for both single mask and double mask triple GEM detector prototypes. Variation of the gain and the energy resolution has also been measured by varying either the drift voltage, transfer voltage and induction voltage keeping other voltages constant. The results of the systematic measurements have been presented.

  5. Development of GEM trigger electronics for the J-PARC E16 experiment

    NASA Astrophysics Data System (ADS)

    Obara, Y.; Hamada, E.; Ikeno, M.; Kawama, D.; Morino, Y.; Nakai, W.; Ozawa, K.; Sendai, H.; Takahashi, T. N.; Tanaka, M. M.; Uchida, T.; Yokkaichi, S.

    2015-12-01

    At the J-PARC E16 experiment[1], we measure mass spectra of vector mesons in nuclei from the e+e- decay channel with high precision and high statistics. We have developed the trigger system consisting of newly developed ASD ASICs which can extract signals from the GEM foil used as a cathode plane of the induction gap in a GEM chamber and digital electronics using FPGAs which processes binary signals from the ASIC.

  6. Performance Evaluation of the COBRA GEM for the Application of the TPC

    NASA Astrophysics Data System (ADS)

    Terasaki, Kohei; Hamagaki, Hideki; Gunji, Taku; Yamaguchi, Yorito

    2014-09-01

    Suppression of the back-drifting ions from avalanche region to drift space (IBF: Ion Backflow) is the key for a Time Projection Chamber (TPC) since IBF easily distorts the drift field. To suppress IBF, Gating Grid system is widely used for the TPC but this limits the data taking rate. Gas Electron Multiplier (GEM) has advantages in the reduction of IBF and high rate capability. By adopting GEM, it is possible to run a TPC continuously under high rate and high multiplicity conditions. Motivated by the study of IBF reduction for RICH with Thick COBRA, which has been developed by F. A. Amero et al., we developed COBRA GEMs for the application of a TPC. With a stack configuration, IBF reaches about 0.1 ~ 0.5%, which is ×5--10 better IBF than the standard GEMs. However, the measured energy resolution with COBRA is 20% (σ) and this is much worse than the resolution with standard GEMs. Measurement of long-time stability of gain indicates that gain of COBRA varies significantly due to charging up effect. Simulation studies based on Garfield++ are performed for understanding quantitatively the reasons of worse energy resolution and instability of gain. In this presentation, we will report the simulation studies together with the measured performance of the COBRA GEM.

  7. A new gravitational model for the earth from satellite tracking data - GEM-T1

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Lerch, F. J.; Putney, B. H.; Christodoulidis, D. C.; Smith, D. E.

    1988-01-01

    A computation of a terrestrial gravitational field model called the Goddard Earth Model GEM-T1 is discussed and compared to previous models, including the GEM-L2. The software tools were redesigned for the model, allowing for the optimization of the technique of relative data weighting and model estimation used in GEM solutions. The GEM-T1 model provides a simultaneous solution for a gravity model in spherical harmonics complete to degree and order 36, a subset of 66 ocean tidal coefficients for the long-wavelength components of 12 major tides, and 5-day averaged earth rotation and polar motion parameters for the 1980 period on. GEM-T1 was derived from satellite tracking data acquired on 17 different satellites whose inclinations ranged from 15 degrees to polar. A simulation of the TOPEX/POSEIDON orbit using the covariances of the GEM-T1 model was made. Estimated radial error for the simulation was reduced to less than 30 cm rms.

  8. iGEMS: an integrated model for identification of alternative exon usage events

    PubMed Central

    Sood, Sanjana; Szkop, Krzysztof J.; Nakhuda, Asif; Gallagher, Iain J.; Murie, Carl; Brogan, Robert J.; Kaprio, Jaakko; Kainulainen, Heikki; Atherton, Philip J.; Kujala, Urho M.; Gustafsson, Thomas; Larsson, Ola; Timmons, James A.

    2016-01-01

    DNA microarrays and RNAseq are complementary methods for studying RNA molecules. Current computational methods to determine alternative exon usage (AEU) using such data require impractical visual inspection and still yield high false-positive rates. Integrated Gene and Exon Model of Splicing (iGEMS) adapts a gene-level residuals model with a gene size adjusted false discovery rate and exon-level analysis to circumvent these limitations. iGEMS was applied to two new DNA microarray datasets, including the high coverage Human Transcriptome Arrays 2.0 and performance was validated using RT-qPCR. First, AEU was studied in adipocytes treated with (n = 9) or without (n = 8) the anti-diabetes drug, rosiglitazone. iGEMS identified 555 genes with AEU, and robust verification by RT-qPCR (∼90%). Second, in a three-way human tissue comparison (muscle, adipose and blood, n = 41) iGEMS identified 4421 genes with at least one AEU event, with excellent RT-qPCR verification (95%, n = 22). Importantly, iGEMS identified a variety of AEU events, including 3′UTR extension, as well as exon inclusion/exclusion impacting on protein kinase and extracellular matrix domains. In conclusion, iGEMS is a robust method for identification of AEU while the variety of exon usage between human tissues is 5–10 times more prevalent than reported by the Genotype-Tissue Expression consortium using RNA sequencing. PMID:27095197

  9. Properties of the Flight Model Gas Electron Multiplier for the GEMS Mission

    NASA Technical Reports Server (NTRS)

    Takeuchi, Yoko; Kitaguchi, Takao; Hayato, Asami; Tamagawa, Toru; Iwakiri, Wataru; Asami, Fumi; Yoshikawa, Akifumi; Kaneko, Kenta; Enoto, Teruaki; Black, Kevin; Hill, Joanne E.; Jahoda, Keith

    2014-01-01

    We present the gain properties of the gas electron multiplier (GEM) foil in pure dimethyl ether (DME) at 190 Torr. The GEM is one of the micro pattern gas detectors and it is adopted as a key part of the X-ray polarimeter for the GEMS mission. The X-ray polarimeter is a time projection chamber operating in pure DME gas at 190 Torr. We describe experimental results of (1) the maximum gain the GEM can achieve without any discharges, (2) the linearity of the energy scale for the GEM operation, and (3) the two-dimensional gain variation of the active area. First, our experiment with 6.4 keV X-ray irradiation of the whole GEM area demonstrates that the maximum effective gain is 2 x 10(exp 4) with the applied voltage of 580 V. Second, the measured energy scale is linear among three energies of 4.5, 6.4, and 8.0 keV. Third, the two-dimensional gain mapping test derives the standard deviation of the gain variability of 7% across the active area.

  10. iGEMS: an integrated model for identification of alternative exon usage events.

    PubMed

    Sood, Sanjana; Szkop, Krzysztof J; Nakhuda, Asif; Gallagher, Iain J; Murie, Carl; Brogan, Robert J; Kaprio, Jaakko; Kainulainen, Heikki; Atherton, Philip J; Kujala, Urho M; Gustafsson, Thomas; Larsson, Ola; Timmons, James A

    2016-06-20

    DNA microarrays and RNAseq are complementary methods for studying RNA molecules. Current computational methods to determine alternative exon usage (AEU) using such data require impractical visual inspection and still yield high false-positive rates. Integrated Gene and Exon Model of Splicing (iGEMS) adapts a gene-level residuals model with a gene size adjusted false discovery rate and exon-level analysis to circumvent these limitations. iGEMS was applied to two new DNA microarray datasets, including the high coverage Human Transcriptome Arrays 2.0 and performance was validated using RT-qPCR. First, AEU was studied in adipocytes treated with (n = 9) or without (n = 8) the anti-diabetes drug, rosiglitazone. iGEMS identified 555 genes with AEU, and robust verification by RT-qPCR (∼90%). Second, in a three-way human tissue comparison (muscle, adipose and blood, n = 41) iGEMS identified 4421 genes with at least one AEU event, with excellent RT-qPCR verification (95%, n = 22). Importantly, iGEMS identified a variety of AEU events, including 3'UTR extension, as well as exon inclusion/exclusion impacting on protein kinase and extracellular matrix domains. In conclusion, iGEMS is a robust method for identification of AEU while the variety of exon usage between human tissues is 5-10 times more prevalent than reported by the Genotype-Tissue Expression consortium using RNA sequencing. PMID:27095197

  11. Performance of a Medium-Size Area nGEM Detector for Neutron Beam Diagnostics

    NASA Astrophysics Data System (ADS)

    Croci, G.; Cazzaniga, C.; Albani, G.; Muraro, A.; Claps, G.; Cavenago, M.; Grosso, G.; Murtas, F.; Pasqualotto, R.; Cippo, E. Perelli; Rebai, M.; Tardocchi, M.; Gorini, G.

    Fast neutron detectors with a sub-centimetric space resolution are required in order to qualify neutron beams in applications related to magnetically-controlled nuclear fusion plasmas and to spallation sources. Based on the results obtained with small area prototypes, the first medium-size (20 x 35.2 cm2 active area) nGEM detector has been realized for both the CNESM diagnostic system of the SPIDER NBI prototype for ITER and as a beam monitor for fast neutrons beam lines at spallation sources, too. The nGEM is a Triple GEM gaseous detector equipped with polyethylene layers used to convert fast neutrons into recoil protons through the elastic scattering process. This paper describes the performance of the medium-size nGEM detector tested at the VESUVIO beam line of the ISIS spallation source. Being this detector the actual largest area fast neutron detector based on the GEM technology, particular attention was paid in the study of detector response in different points over the active area. Measurements of GEM counting rate (both as a function of VGEM and of time) and of the capability of the detector to reconstruct the beam in different positions are presented. This detector serves as a basis for the realization of an even larger area detector that will be used in the MITICA NBI prototype for ITER that represents the evolution of SPIDER.

  12. GEM*STAR: Time for an Alternative Way Forward

    NASA Astrophysics Data System (ADS)

    Vogelaar, R. Bruce

    2011-10-01

    The presumption that nuclear reactors will retain their role in global energy production is constantly being challenged - even more so following recent events at Fukushima. Nuclear energy, despite being ``green,'' has inexorably been coupled in the public mind with three paramount concerns: safety, weapons proliferation, and waste (and then ultimately cost). Over the past four decades, the safety of deployed fleets has greatly improved, yet the capital and political costs of a ``nuclear energy option'' appear insurmountable in several countries. The US approach to civilian nuclear energy has become deeply entrenched, first through choices made by the military, and then by the deployed nuclear reactor fleet. This extends to the research agencies as well, to the point where basic sciences and nuclear energy operate in separate spheres. But technologies and priorities have changed, and the time has arrived where a transformative re-think of nuclear energy is not only possible, but urgent. And nuclear physicists are uniquely positioned to accomplish this. This talk will show that by asking, and answering,``what would an accelerator-driven civilian nuclear energy program look like,'' ADNA Corporation's GEM*STAR design directly addresses all three fundamental concerns: safety, proliferation, and waste - and also the final hurdle: cost. GEM*STAR is not an ``add-on'' (to either Project-X, or GEN III+), but rather a base-line energy production capacity, for either electricity or transport fuel production. It integrates and advances the molten-salt reactor technology developed at ORNL, the MW beam accelerator technologies developed by basic sciences, and a reactor/target design optimized for accelerator driven-systems. The results include: the ability to use LWR spent fuel without reprocessing or additional waste; the ability to use natural uranium; no critical mass ever present; orders-of-magnitude less volatile radioactivity in the core; more efficient use of, and deeper

  13. The liquid helium thermosyphon for the GEM detector magnet

    SciTech Connect

    Warren, R.P.

    1993-05-04

    The GEM detector magnet, a horizontal solenoid 19.5 m in diameter and wound with a niobium-titanium cable in conduit, will be located with it`s axis 19.5 m below grade. The conductor is wound on the inside of an aluminum bobbin which is cooled by liquid helium which flows by natural convection in a thermosyphon loop from a large storage dewar located at the ground surface. The function of the thermosyphon system is to absorb the environmental heat load as well as any internally generated heat. In the first category is included that heat which is transfered to the magnet by way of the mechanical supports, the insulation and the current leads. The internally generated heat includes the resistive heating within the normally conducting conductor splices and the inductive heating of the bobbin during current transients. Though similar systems have been employed elsewhere, there are some unique aspects to the present design. By taking advantage of the large vertical head available, the parallel heat exchanger passes within the magnet remain sub-cooled, thus insuring single phase coolant within the magnet. It is believed that this will be the first instance of such a large vertical head being used to this advantage in a helium system.

  14. GEMS Observations of Obscured Galactic Bulge Globular Clusters

    NASA Astrophysics Data System (ADS)

    Geisler, Douglas; Saracino, Sara; Dalessandro, Emanuele; Ferraro, Francesco; Lanzoni, Barbara; Mauro, Francesco; Villanova, Sandro; Moni Bidin, Christian; Miocchi, Paolo; Massari, Davide

    2016-01-01

    We will present results for several heavily obscured Galactic globular clusters lying in the bulge, including Liller 1 and NGC 6624. The observations were obtained exploiting the exceptional high-resolution capabilities of the near-IR camera GSAOI combined with the Gemini Multi-Conjugate Adaptive Optics System at the GEMINI South Telescope. The images in the J and K bands are generally sub-0.1", only slightly larger than the diffraction limit of the telescope, yielding the deepest and most accurate color-magnitude diagrams obtained so far from the ground for these clusters. We derived the structural and physical properties of both clusters, supplementing the GEMS data with data from the Vista Variables in the Via Lactea project. We were also able to investigate the age of NGC 6624. We find that Liller 1 is significantly less concentrated and less extended than previously thought. We estimated the mass of Liller 1 to be 2.3 million solar masses, comparable to that of the most massive clusters in the Galaxy. Also, Liller 1 has the second-highest collision rate among all star clusters in the Galaxy, thus confirming that it is an ideal environment for the formation of collisional objects (such as millisecond pulsars). The NGC 6624 CMD reveals the second knee of the mainsequence and allows us to determine a very accurate age of 12.0 +-0.5 Gyr.

  15. On-sky validation of LIFT on GEMS

    NASA Astrophysics Data System (ADS)

    Plantet, Cedric; Meimon, Serge; Conan, Jean-Marc; Neichel, Benoit; Fusco, Thierry

    2013-12-01

    Laser assisted adaptive optics systems rely on Laser Guide Star (LGS) Wave-Front Sensors (WFS) for high order aberration measurements, and rely on Natural Guide Stars (NGS) WFS to complement the measurements on low orders such as tip-tilt and focus. The sky-coverage of the whole system is therefore related to the limiting magnitude of the NGS WFS. LIFT is a novel WFS based on the analysis of a well corrected full aperture short exposure image, simply with a small astigmatism offset. It allows a 1 magnitude gain over the usually used 2x2 Shack-Hartmann WFS. Its noise propagation is comparable to a 4-pixel pyramid sensor without modulation. Besides, it requires a much more simple hardware, making it a reliable and easy to set up solution. Early this year, LIFT came out of the lab and has been tested on GEMS, the multiconjugate adaptive optics system of Gemini South. We present here the first on-sky IR wave-front sensing data obtained with LIFT. We show that these results constitute a clear on-sky demonstration of the LIFT concept.

  16. Radiation tests for a single-GEM-loaded gaseous detector

    NASA Astrophysics Data System (ADS)

    Lee, Kyong Sei; Hong, Byungsik; Park, Sung Keun; Kim, Sang Yeol

    2014-11-01

    We report on a systematic study of a single-gas-electron-multiplier (GEM)-loaded gaseous detector developed for precision measurements of high-energy particle beams and for dose verification in particle therapy. In the present study, a 256-channel prototype detector having an active area of 16 × 16 cm2 and operating using a continuous current-integration-mode signal-processing method was manufactured and tested with X-rays emitted from a 70-kV X-ray generator and 43-MeV protons provided by the MC50 proton cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). The amplified detector response was measured for X-rays with an intensity of about 5 × 106 Hz cm-2. The linearity of the detector response to the particle flux was examined and validated by using 43-MeV proton beams. The non-uniform development of the amplification for the gas electrons in space was corrected by applying a proper calibration to the channel responses of the measured beam-profile data. We conclude from the radiation tests that the detector developed in the present study will allow us to perform quality measurements of various high-energy particle beams and to apply the technology to dose-verification measurements in particle therapy.

  17. Geopotential models of the Earth from satellite tracking, altimeter and surface gravity observations: GEM-T3 and GEM-T3S

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Nerem, R. S.; Putney, B. H.; Felsentreger, T. L.; Sanchez, B. V.; Klosko, S. M.; Patel, G. B.; Williamson, R. G.; Chinn, D. S.; Chan, J. C.

    1992-01-01

    Improved models of the Earth's gravitational field have been developed from conventional tracking data and from a combination of satellite tracking, satellite altimeter and surface gravimetric data. This combination model represents a significant improvement in the modeling of the gravity field at half-wavelengths of 300 km and longer. Both models are complete to degree and order 50. The Goddard Earth Model-T3 (GEM-T3) provides more accurate computation of satellite orbital effects as well as giving superior geoidal representation from that achieved in any previous GEM. A description of the models, their development and an assessment of their accuracy is presented. The GEM-T3 model used altimeter data from previous satellite missions in estimating the orbits, geoid, and dynamic height fields. Other satellite tracking data are largely the same as was used to develop GEM-T2, but contain certain important improvements in data treatment and expanded laser tracking coverage. Over 1300 arcs of tracking data from 31 different satellites have been used in the solution. Reliable estimates of the model uncertainties via error calibration and optimal data weighting techniques are discussed.

  18. The MIT Program, Competition, and Ethics

    NASA Astrophysics Data System (ADS)

    Bradt, Hale V.

    2013-01-01

    The MIT program in x-ray astronomy was, and still is, diverse and productive. Bruno Rossi and later George Clark, as the nominal leaders of the “x-ray astronomy group” created a “hands-off” culture wherein individual researchers could develop their own independent programs. Walter Lewin, Claude Canizares, and I as well as those in the next academic generations, e.g., Saul Rappaport and George Ricker, were able to thrive in this environment. MIT researchers were principal investigators or providers of x-ray instruments on sounding rockets and balloons in the 1960s and then in later years on nine satellite missions, OSO-7, SAS-3, HEAO-1, Einstein, ASCA, RXTE, Chandra, HETE-2, and Suzaku. Such a diverse program involved collaborations with other institutions and of course striving for primacy in discovery and competition for NASA resources. Looking back, I see a high degree of ethical behavior among the observational x-ray community during those years. In competition, we remembered that we might well be collaborating the following year and behaved accordingly. Many of us in the x-ray community had been friends since graduate school days and did not want to lose those relationships. Am I viewing the past through rose colored glasses? I think not. A vignette on this topic: In 1967, I was debating vigorously with Herb Gursky of AS&E about which institution, MIT or AS&E, should be the lead on the fourth paper (Oda et al. 1967, ApJ 148, L5) based on data from the 1966 AS&E rocket flight which had led to Allan Sandage’s (and Japanese) identification of Sco X-1 (Sandage, et al. 1966, ApJ. 146, 316). I and my Italian colleague, Gianfranco Spada, and our Japanese colleague, Minoru Oda, both then visiting MIT, had actively supported that flight. After one rather heated discussion with Herb about this, - I was the heated one; he always remained calm - he left my office saying: “Hale, however this comes out, let’s remain friends.” I treasured that comment and

  19. MIT Space Engineering Research Center testbed programs

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Miller, David W.

    1991-01-01

    The Space Engineering Research Center (SERC) at M.I.T., started in July 1988, has completed two and one-half years of research. This Semi-Annual Report presents annotated viewgraph material presented at the January 1991 Steering Committee and Technical Representative Review. The objective of the Space Engineering Research Center is to develop and disseminate a unified technology of controlled structures. There has been continued evolution of the concept of intelligent structures (including in this past year the first successful embedding of a microelectronic component into a structural element).

  20. Production status of the JLAB Hall-A GEM and Si μstrip Tracker

    NASA Astrophysics Data System (ADS)

    Basile, E.; Bellini, V.; Capogni, M.; Colilli, S.; Cisbani, E.; Diefenbach, J.; De Leo, R.; De Persio, F.; Frullani, S.; Giuliani, F.; Lucentini, M.; Meddi, F.; Minutoli, Saverio; Musico, Paolo; Noto, F.; De Oliveira, R.; Perrino, R.; Santavenere, F.; Urciuoli, G.

    2013-08-01

    We developed and tested a new charged particle tracking system, able to operate in high luminosity experiments, which will be installed at Jefferson Laboratory HallA (VA, USA) for optimally exploit the new 12 GeV energy electron beam available at the end of 2013. The tracker is made of six GEM (Gas Electron Multiplier) large chambers and two 10×20 cm2 planes of SIlicon microstrip Detectors (SIDs). Each GEM chamber is composed by three 40×50 cm2 GEM modules, with two-dimensional strip readout, with expected spatial resolution of about 70 μm. The same dedicated acquisition system will be used for both detectors (GEM & SID) for a grand total of more than 50,000 channels. The readout electronics is divided into two parts: the front-end cards (based on the existing APV25 chip), hosted on the detectors periphery and the digitizer, a multi purpose VME-64x/VXS board located far from the high radiation environment. The very same electronics has been adopted by the Olympus experiment (DESY, Hamburg, D) to read out the six GEM chambers of its luminosity monitor. The developed detectors and electronics are now ready for the production, which will last for the next 2 years.

  1. Gravity model improvement using GEOS 3 /GEM 9 and 10/. [and Seasat altimetry data

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Wagner, C. A.; Klosko, S. M.; Laubscher, R. E.

    1979-01-01

    Although errors in previous gravity models have produced large uncertainties in the orbital position of GEOS 3, significant improvement has been obtained with new geopotential solutions, Goddard Earth Model (GEM) 9 and 10. The GEM 9 and 10 solutions for the potential coefficients and station coordinates are presented along with a discussion of the new techniques employed. Also presented and discussed are solutions for three fundamental geodetic reference parameters, viz. the mean radius of the earth, the gravitational constant, and mean equatorial gravity. Evaluation of the gravity field is examined together with evaluation of GEM 9 and 10 for orbit determination accuracy. The major objectives of GEM 9 and 10 are achieved. GEOS 3 orbital accuracies from these models are about 1 m in their radial components for 5-day arc lengths. Both models yield significantly improved results over GEM solutions when compared to surface gravimetry, Skylab and GEOS 3 altimetry, and highly accurate BE-C (Beacon Explorer-C) laser ranges. The new values of the parameters discussed are given.

  2. An improved error assessment for the GEM-T1 gravitational model

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Marsh, J. G.; Klosko, S. M.; Patel, G. B.; Chinn, D. S.; Pavlis, E. C.; Wagner, C. A.

    1991-01-01

    Several tests have been designed to estimate the correct error variances for the GEM-T1 gravitational solution that was derived exclusively from satellite tracking data. The basic method uses both independent and dependent subset data solutions and produces a coefficient-by-coefficient estimate of the model uncertainties. The GEM-T1 errors have been further analyzed using a method based on eigenvalue-eigenvector analysis, which calibrates the entire covariance matrix. Dependent satellite data sets and independent altimetric, resonant satellite, and surface gravity data sets all confirm essentially the same error assessment. The calibration test results yield very stable calibration factors, which vary only by approximately 10 percent over the range of tests performed. Based on these calibrated error estimates, GEM-T1 is a significantly improved solution, which to degree and order 8 is twice as accurate as earlier satellite derived models like GEM-L2. Also, by being complete to degree and order 36, GEM-T1 is more complete and has significantly reduced aliasing effects that were present in previous models.

  3. Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE) GEM Manual

    SciTech Connect

    C. L. Smith; J. Schroeder; S. T. Beck

    2008-08-01

    The Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE) is a software application developed for performing a complete probabilistic risk assessment (PRA) using a personal computer running the Microsoft Windows? operating system. SAPHIRE is primarily funded by the U.S. Nuclear Regulatory Commission (NRC) and developed by the Idaho National Laboratory (INL). The INL's primary role in this project is that of software developer and tester. Using the SAPHIRE analysis engine and relational database is a complementary program called GEM. GEM has been designed to simplify using existing PRA analysis for activities such as the NRC’s Accident Sequence Precursor program. In this report, the theoretical framework behind GEM-type calculations are discussed in addition to providing guidance and examples for performing evaluations when using the GEM software. As part of this analysis framework, the two types of GEM analysis are outlined, specifically initiating event (where an initiator occurs) and condition (where a component is failed for some length of time) assessments.

  4. Identifying the Source of Gem Diamonds: Requirements for a Certification System

    NASA Astrophysics Data System (ADS)

    Shigley, J. E.

    2002-05-01

    Recent civil conflicts in several countries, in which profits from the sales of gem diamonds have supported the rival factions, have forced the jewelry industry to confront the need to certify the geographic sources of gem diamonds. The goals of this program are to prohibit the sale of so-called "conflict diamonds", and to prevent the loss of consumer confidence. Efforts to identify unique characteristics of gem diamonds have been hampered so far by the absence of chemical or physical features that are diagnostic of particular sources, and the lack of a representative collection of diamonds from major producing areas that would be required for a rigorous scientific study. The jewelry industry has therefore adopted plans to track gem diamonds from the mine through the manufacturing process to the consumer. Practical requirements for implementation of such a certification system will be summarized. Any proposed solutions for determining the sources of gem diamonds by some analytical technique, or for following diamonds from the mine, must take into account the annual production of several tens of millions of carats of rough diamonds, which are transformed during manufacturing into several hundreds of millions of polished gemstones (with an average weight of only about 0.03 carat, or 0.006 gram).

  5. Applications of Mapping and Tomographic Techniques in Gem Sciences

    NASA Astrophysics Data System (ADS)

    Shen, A. H.

    2014-12-01

    Gem Sciences are scientific studies of gemstones - their genesis, provenance, synthesis, enhancement, treatment and identification. As high quality forms of specific minerals, the gemstones exhibit unusual physical properties that are usually unseen in the regular counterparts. Most gemstones are colored by trace elements incorporated in the crystal lattice during various growth stages; forming coloration zones of various scales. Studying the spectral and chemical contrast across color zones helps elucidating the origins of colors. These are done by UV-visible spectrometers with microscope and LA-ICPMS in modern gemological laboratories. In the case of diamonds, their colored zones arise from various structural defects incorporated in different growth zones and are studied with FTIR spectrometers with IR microscope and laser photoluminescence spectrometers. Advancement in modern synthetic techniques such as chemical vapor deposition (CVD) has created some problem for identification. Some exploratory experiments in carbon isotope mapping were done on diamonds using SIMS. The most important issue in pearls is to identify one particular pearl being a cultured one or a natural pearl. The price difference can be enormous. Classical way of such identification is done by x-ray radiographs, which clearly show the bead and the nacre. Modern cultured pearl advancement has eliminated the need for an artificial bead, but a small piece of tissue instead. Nowadays, computer x-ray tomography (CT) scanning devices are used to depict the clear image of the interior of a pearl. In the Chinese jade market, filling fissures with epoxy and/or wax are very commonly seen. We are currently exploring Magnetic Resonance Imaging (MRI) technique to map the distribution of artificial resin within a polycrystalline aggregates.

  6. Decadal predictions with the HiGEM high resolution global coupled climate model: description and basic evaluation

    NASA Astrophysics Data System (ADS)

    Shaffrey, L. C.; Hodson, D.; Robson, J.; Stevens, D. P.; Hawkins, E.; Polo, I.; Stevens, I.; Sutton, R. T.; Lister, G.; Iwi, A.; Smith, D.; Stephens, A.

    2016-04-01

    This paper describes the development and basic evaluation of decadal predictions produced using the HiGEM coupled climate model. HiGEM is a higher resolution version of the HadGEM1 Met Office Unified Model. The horizontal resolution in HiGEM has been increased to 1.25° × 0.83° in longitude and latitude for the atmosphere, and 1/3° × 1/3° globally for the ocean. The HiGEM decadal predictions are initialised using an anomaly assimilation scheme that relaxes anomalies of ocean temperature and salinity to observed anomalies. 10 year hindcasts are produced for 10 start dates (1960, 1965,..., 2000, 2005). To determine the relative contributions to prediction skill from initial conditions and external forcing, the HiGEM decadal predictions are compared to uninitialised HiGEM transient experiments. The HiGEM decadal predictions have substantial skill for predictions of annual mean surface air temperature and 100 m upper ocean temperature. For lead times up to 10 years, anomaly correlations (ACC) over large areas of the North Atlantic Ocean, the Western Pacific Ocean and the Indian Ocean exceed values of 0.6. Initialisation of the HiGEM decadal predictions significantly increases skill over regions of the Atlantic Ocean, the Maritime Continent and regions of the subtropical North and South Pacific Ocean. In particular, HiGEM produces skillful predictions of the North Atlantic subpolar gyre for up to 4 years lead time (with ACC > 0.7), which are significantly larger than the uninitialised HiGEM transient experiments.

  7. Historisches Rätsel Physik mit Gewehr und Eiern

    NASA Astrophysics Data System (ADS)

    Loos, Andreas

    2003-11-01

    Es fing schon gut an: Mit zehn Jahren saß der begabte Junge bereits in der Universität, wo ihn kein Geringerer als sein Vater persönlich unterrichtete. Damit schlug dieser zwei Fliegen mit einer Klappe: Sein Sohn lernte etwas Gescheites, und er war zugleich in sicherer Obhut.

  8. MMPI and MIT Discriminators of Biogenic and Psychogenic Impotence

    ERIC Educational Resources Information Center

    Beutler, Larry E.; And Others

    1975-01-01

    Male patients complaining of impotence (N=32) were administered the Male Impotence Test (MIT) and the Minnesota Multiphasic Personality Inventory (MMPI). The results suggested that the MIT is without value for differentiating between psychogenic and biogenic impotence, whereas two rules from the MMPI appropriately classified 90 percent of the…

  9. Physik gestern und heute: Visualisierung mit der Schlierenmethode

    NASA Astrophysics Data System (ADS)

    Heering, Peter

    2006-07-01

    Der Name des österreichischen Forschers Ernst Mach ist heute noch mit der Schallgeschwindigkeit verbunden. Diese Auszeichnung resultiert aus Machs Untersuchungen, wie sich Projektile mit Überschallgeschwindigkeit durch die Luft bewegen. Gerade in jüngster Zeit hat die Anwendung derartiger Methoden durch technische Modifikationen wieder einen Aufschwung erfahren.

  10. The M.I.T. INSITE Space System.

    ERIC Educational Resources Information Center

    Cyros, Kreon L.

    1989-01-01

    The M.I.T. INSITE (INstitutional Space Inventory TEchniques) system, a management information system developed specifically to provide facilities management information for decision making in the planning stages, is described. Since 1973, M.I.T. has shared the INSITE technology with a consortium of users from academic, health care, corporate and…

  11. Study of gain variation as a function of physical parameters of GEM foil

    NASA Astrophysics Data System (ADS)

    Das, Supriya

    2016-07-01

    The ALICE experiment at LHC has planned to upgrade the TPC by replacing the MWPC with GEM based detecting elements to restrict the IBF to a tolerable value. However the variation of the gain as a function of physical parameters of industrially produced large size GEM foils is needed to be studied as a part of the QA procedure for the detector. The size of the electron avalanche and consequently the gain for GEM based detectors depend on the electric field distribution inside the holes. Geometry of a hole plays an important role in defining the electric field inside it. In this work we have studied the variation of the gain as a function of the hole diameters using Garfield++ simulation package.

  12. Improved model of the Earth's gravitational field: GEM-T1

    SciTech Connect

    Marsh, J.G.; Lerch, F.J.; Christodoulidis, D.C.; Putney, B.H.; Felsentreger, T.L.; Sanchez, B.V.; Smith, D.E.; Klosko, S.M.; Martin, T.V.; Pavlis, E.C.

    1987-07-01

    Goddard Earth Model T1 (GEM-T1), which was developed from an analysis of direct satellite tracking observations, is the first in a new series of such models. GEM-T1 is complete to degree and order 36. It was developed using consistent reference parameters and extensive earth and ocean tidal models. It was simultaneously solved for gravitational and tidal terms, earth orientation parameters, and the orbital parameters of 580 individual satellite arcs. The solution used only satellite tracking data acquired on 17 different satellites and is predominantly based upon the precise laser data taken by third generation systems. In all, 800,000 observations were used. A major improvement in field accuracy was obtained. For marine geodetic applications, long wavelength geoidal modeling is twice as good as in earlier satellite-only GEM models. Orbit determination accuracy has also been substantially advanced over a wide range of satellites that have been tested.

  13. Coordinated Chemical and Isotropic Studies of IDPS: Comparison of Circumstellar and Solar GEMS Grains

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Messenger, S.

    2007-01-01

    Silicate stardust in IDPs and meteorites include forsterite, amorphous silicates, and GEMS grains [1]. Amorphous presolar silicates are much less abundant than expected based on astronomical models [2], possibly destroyed by parent body alteration. A more accurate accounting of presolar silicate mineralogy may be preserved in anhydrous IDPs. Here we present results of coordinated TEM and isotopic analyses of an anhydrous IDP (L2005AL5) that is comprised of crystalline silicates and sulfides, GEMS grains, and equilibrated aggregates embedded in a carbonaceous matrix. Nanometer-scale quantitative compositional maps of all grains in two microtome thin sections were obtained with a JEOL 2500SE. These sections were then subjected to O and N isotopic imaging with the JSC NanoSIMS 50L. Coordinated high resolution chemical maps and O isotopic com-positions were obtained on 11 GEMS grains, 8 crystalline grains, and 6 equilibrated aggregates.

  14. OSG-GEM: Gene Expression Matrix Construction Using the Open Science Grid.

    PubMed

    Poehlman, William L; Rynge, Mats; Branton, Chris; Balamurugan, D; Feltus, Frank A

    2016-01-01

    High-throughput DNA sequencing technology has revolutionized the study of gene expression while introducing significant computational challenges for biologists. These computational challenges include access to sufficient computer hardware and functional data processing workflows. Both these challenges are addressed with our scalable, open-source Pegasus workflow for processing high-throughput DNA sequence datasets into a gene expression matrix (GEM) using computational resources available to U.S.-based researchers on the Open Science Grid (OSG). We describe the usage of the workflow (OSG-GEM), discuss workflow design, inspect performance data, and assess accuracy in mapping paired-end sequencing reads to a reference genome. A target OSG-GEM user is proficient with the Linux command line and possesses basic bioinformatics experience. The user may run this workflow directly on the OSG or adapt it to novel computing environments. PMID:27499617

  15. Use of laser induced breakdown spectroscopy in the determination of gem provenance: beryls

    SciTech Connect

    McManus, Catherine E.; McMillan, Nancy J.; Harmon, Russell S.; Whitmore, Robert C.; De Lucia, Frank C. Jr.; Miziolek, Andrzej W

    2008-11-01

    The provenance of gem stones has been of interest to geologists, gemologists, archeologists, and historians for centuries. Laser induced breakdown spectroscopy (LIBS) provides a minimally destructive tool for recording the rich chemical signatures of gem beryls (aquamarine, goshenite, heliodor, and morganite). Broadband LIBS spectra of 39 beryl (Be3Al2Si6O18) specimens from 11 pegmatite mines in New Hampshire, Connecticut, and Maine (USA) are used to assess the potential of using principal component analysis of LIBS spectra to determine specimen provenance. Using this technique, beryls from the three beryl-bearing zones in the Palermo no. 1 pegmatite (New Hampshire) can be recognized. However, the compositional variation within this single mine is comparable to that in beryls from all three states. Thus, a very large database with detailed location metadata will be required to routinely determine gem beryl provenance.

  16. Use of laser induced breakdown spectroscopy in the determination of gem provenance: beryls.

    PubMed

    McManus, Catherine E; McMillan, Nancy J; Harmon, Russell S; Whitmore, Robert C; De Lucia, Frank C; Miziolek, Andrzej W

    2008-11-01

    The provenance of gem stones has been of interest to geologists, gemologists, archeologists, and historians for centuries. Laser induced breakdown spectroscopy (LIBS) provides a minimally destructive tool for recording the rich chemical signatures of gem beryls (aquamarine, goshenite, heliodor, and morganite). Broadband LIBS spectra of 39 beryl (Be(3)Al(2)Si(6)O(18)) specimens from 11 pegmatite mines in New Hampshire, Connecticut, and Maine (USA) are used to assess the potential of using principal component analysis of LIBS spectra to determine specimen provenance. Using this technique, beryls from the three beryl-bearing zones in the Palermo #1 pegmatite (New Hampshire) can be recognized. However, the compositional variation within this single mine is comparable to that in beryls from all three states. Thus, a very large database with detailed location metadata will be required to routinely determine gem beryl provenance. PMID:19122706

  17. OSG-GEM: Gene Expression Matrix Construction Using the Open Science Grid

    PubMed Central

    Poehlman, William L.; Rynge, Mats; Branton, Chris; Balamurugan, D.; Feltus, Frank A.

    2016-01-01

    High-throughput DNA sequencing technology has revolutionized the study of gene expression while introducing significant computational challenges for biologists. These computational challenges include access to sufficient computer hardware and functional data processing workflows. Both these challenges are addressed with our scalable, open-source Pegasus workflow for processing high-throughput DNA sequence datasets into a gene expression matrix (GEM) using computational resources available to U.S.-based researchers on the Open Science Grid (OSG). We describe the usage of the workflow (OSG-GEM), discuss workflow design, inspect performance data, and assess accuracy in mapping paired-end sequencing reads to a reference genome. A target OSG-GEM user is proficient with the Linux command line and possesses basic bioinformatics experience. The user may run this workflow directly on the OSG or adapt it to novel computing environments. PMID:27499617

  18. An improved model of the Earth's gravitational field: GEM-T1

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Lerch, F. J.; Christodoulidis, D. C.; Putney, B. H.; Felsentreger, T. L.; Sanchez, B. V.; Smith, D. E.; Klosko, S. M.; Martin, T. V.; Pavlis, E. C.

    1987-01-01

    Goddard Earth Model T1 (GEM-T1), which was developed from an analysis of direct satellite tracking observations, is the first in a new series of such models. GEM-T1 is complete to degree and order 36. It was developed using consistent reference parameters and extensive earth and ocean tidal models. It was simultaneously solved for gravitational and tidal terms, earth orientation parameters, and the orbital parameters of 580 individual satellite arcs. The solution used only satellite tracking data acquired on 17 different satellites and is predominantly based upon the precise laser data taken by third generation systems. In all, 800,000 observations were used. A major improvement in field accuracy was obtained. For marine geodetic applications, long wavelength geoidal modeling is twice as good as in earlier satellite-only GEM models. Orbit determination accuracy has also been substantially advanced over a wide range of satellites that have been tested.

  19. Further developments and beam tests of the gas electron multiplier (GEM)

    NASA Astrophysics Data System (ADS)

    Benlloch, J.; Bressan, A.; Capeáns, M.; Gruwé, M.; Hoch, M.; Labbé, J. C.; Placci, A.; Ropelewski, L.; Sauli, F.

    1998-12-01

    We describe the development and operation of the Gas Electron Multiplier (GEM), a thin insulating foil metal-clad on both sides and perforated by a regular pattern of small holes. The mesh can be incorporated into the gas volume of an active detector to provide a first amplification channel for electrons, or used as stand alone. We report on the basic properties of GEMs manufactured with different geometries and operated in several gas mixtures as well as on their long-term stability after accumulation of charge equivalent to several years of operation in high-luminosity experiments. Optimized GEMs reach gains close to 10 000 at safe operating voltages, permitting the detection of ionizing tracks, without other amplifying elements, on a simple Printed Circuit Board (PCB), opening new possibilities for detector design.

  20. Python based integration of GEM detector electronics with JET data acquisition system

    NASA Astrophysics Data System (ADS)

    Zabołotny, Wojciech M.; Byszuk, Adrian; Chernyshova, Maryna; Cieszewski, Radosław; Czarski, Tomasz; Dalley, Simon; Hogben, Colin; Jakubowska, Katarzyna L.; Kasprowicz, Grzegorz; Poźniak, Krzysztof; Rzadkiewicz, Jacek; Scholz, Marek; Shumack, Amy

    2014-11-01

    This paper presents the system integrating the dedicated measurement and control electronic systems for Gas Electron Multiplier (GEM) detectors with the Control and Data Acquisition system (CODAS) in the JET facility in Culham, England. The presented system performs the high level procedures necessary to calibrate the GEM detector and to protect it against possible malfunctions or dangerous changes in operating conditions. The system also allows control of the GEM detectors from CODAS, setting of their parameters, checking their state, starting the plasma measurement and to reading the results. The system has been implemented using the Python language, using the advanced libraries for implementation of network communication protocols, for object based hardware management and for data processing.

  1. A COMSOL-GEMS interface for modeling coupled reactive-transport geochemical processes

    NASA Astrophysics Data System (ADS)

    Azad, Vahid Jafari; Li, Chang; Verba, Circe; Ideker, Jason H.; Isgor, O. Burkan

    2016-07-01

    An interface was developed between COMSOL MultiphysicsTM finite element analysis software and (geo)chemical modeling platform, GEMS, for the reactive-transport modeling of (geo)chemical processes in variably saturated porous media. The two standalone software packages are managed from the interface that uses a non-iterative operator splitting technique to couple the transport (COMSOL) and reaction (GEMS) processes. The interface allows modeling media with complex chemistry (e.g. cement) using GEMS thermodynamic database formats. Benchmark comparisons show that the developed interface can be used to predict a variety of reactive-transport processes accurately. The full functionality of the interface was demonstrated to model transport processes, governed by extended Nernst-Plank equation, in Class H Portland cement samples in high pressure and temperature autoclaves simulating systems that are used to store captured carbon dioxide (CO2) in geological reservoirs.

  2. Optical characterization of synthetic faceted gem materials grown from hydrothermal solutions

    NASA Astrophysics Data System (ADS)

    Lu, Taijin; Shigley, James E.

    1998-10-01

    Various non-destructive optical characterization techniques have been used to characterize and identify synthetic gem materials grown from hydrothermal solutions, to include ruby, sapphire, emerald, amethyst and ametrine (amethyst-citrine), from their natural counterparts. The ability to observe internal features, such as inclusions, dislocations, twins, color bands, and growth zoning in gem materials is strongly dependent on the observation techniques and conditions, since faceted gemstones have many polished surfaces which can reflect and scatter light in various directions which can make observation difficult. However, diagnostic gemological properties of these faceted synthetic gem materials can be obtained by choosing effective optical characterization methods, and by modifying optical instruments. Examples of some of the distinctive features of synthetic amethyst, ametrine, pink quartz, ruby and emerald are presented to illustrate means of optical characterization of gemstones. The ability to observe defects by light scattering techniques is discussed.

  3. MAXI/GSC detection of a possible X-ray flare from an dMe binary system YY Gem

    NASA Astrophysics Data System (ADS)

    Nakamura, Y.; Kanetou, S.; Tsuboi, Y.; Sasaki, R.; Ueno, S.; Tomida, H.; Nakahira, S.; Kimura, M.; Ishikawa, M.; Nakagawa, Y. E.; Mihara, T.; Sugizaki, M.; Serino, M.; Shidatsu, M.; Sugimoto, J.; Takagi, T.; Matsuoka, M.; Kawai, N.; Arimoto, M.; Yoshii, T.; Tachibana, Y.; Ono, Y.; Fujiwara, T.; Yoshida, A.; Sakamoto, T.; Kawakubo, Y.; Ohtsuki, H.; Tsunemi, H.; Imatani, R.; Negoro, H.; Nakajima, M.; Tanaka, K.; Masumitsu, T.; Ueda, Y.; Kawamuro, T.; Hori, T.; Yamauchi, M.; Itoh, D.; Yamaoka, K.; Morii, M.

    2015-09-01

    MAXI/GSC observed a possible X-ray flare from a dMe binary system YY Gem. The MAXI/GSC nova alert system triggered on the flare-like event from the position consistent with the active binary system YY Gem during a scan transit at 01:29:00 UT on September 24th 2015.

  4. Gemcitabine-loaded albumin nanospheres (GEM-ANPs) inhibit PANC-1 cells in vitro and in vivo

    NASA Astrophysics Data System (ADS)

    Li, Ji; Di, Yang; Jin, Chen; Fu, Deliang; Yang, Feng; Jiang, Yongjian; Yao, Lie; Hao, Sijie; Wang, Xiaoyi; Subedi, Sabin; Ni, Quanxing

    2013-04-01

    With the development of nanotechnology, special attention has been given to the nanomaterial application in tumor treatment. Here, a modified desolvation-cross-linking method was successfully applied to fabricate gemcitabine-loaded albumin nanospheres (GEM-ANPs), with 110 and 406 nm of mean diameter, respectively. The aim of this study was to assess the drug distribution, side effects, and antitumor activity of GEM-ANPs in vivo. The metabolic viability and flow cytometry analysis revealed that both GEM-ANPs, especially 406-nm GEM-ANPs, could effectively inhibit the metabolism and proliferation and promote the apoptosis of human pancreatic carcinoma (PANC-1) in vitro. Intravenous injection of 406-nm GEM-ANPs exhibited a significant increase of gemcitabine in the pancreas, liver, and spleen of Sprague-Dawley rats ( p < 0.05). Moreover, no signs of toxic side effects analyzed by blood parameter changes were observed after 3 weeks of administration although a high dose (200 mg/kg) of GEM-ANPs were used. Additionally, in PANC-1-induced tumor mice, intravenous injection of 406-nm GEM-ANPs also could effectively reduce the tumor volume by comparison with free gemcitabine. With these findings, albumin nanosphere-loading approach might be efficacious to improve the antitumor activity of gemcitabine, and the efficacy is associated with the size of GEM-ANPs.

  5. Absence of the Thorpe–Ingold Effect by gem-Diphenyl Groups in Ring-Closing Enyne Metathesis

    PubMed Central

    Kim, Yi Jin; Grimm, Jonathan B.; Lee, Daesung

    2007-01-01

    In tandem ring-closing metathesis of alkynyl silaketals containing two different tethered olefins, the gem-dimethyl group showed the expected Thorpe-Ingold effect, thereby giving good level of group selectivity. Unexpectedly, however, the corresponding gem-diphenyl group did not show any Thorpe-Ingold effect for the ring closure reaction. PMID:18046462

  6. Science and Math Explorations for Young Children: A GEMS/PEACHES Handbook for Early Childhood Educators, Childcare Providers, and Parents.

    ERIC Educational Resources Information Center

    Barrett, Katharine; Blinderman, Ellen; Boffen, Beatrice; Echols, Jean; House, Patricia A.; Hosoume, Kimi; Kopp, Jaine

    This handbook is designed to help readers understand the educational philosophy and practice of the PEACHES (Primary Explorations for Children and Educators in Science) and GEMS (Great Explorations in Math and Science) programs, and to assist in using GEMS/PEACHES teachers' guides in schools and child care centers. The handbook outlines techniques…

  7. Gemcitabine-loaded albumin nanospheres (GEM-ANPs) inhibit PANC-1 cells in vitro and in vivo

    PubMed Central

    2013-01-01

    With the development of nanotechnology, special attention has been given to the nanomaterial application in tumor treatment. Here, a modified desolvation-cross-linking method was successfully applied to fabricate gemcitabine-loaded albumin nanospheres (GEM-ANPs), with 110 and 406 nm of mean diameter, respectively. The aim of this study was to assess the drug distribution, side effects, and antitumor activity of GEM-ANPs in vivo. The metabolic viability and flow cytometry analysis revealed that both GEM-ANPs, especially 406-nm GEM-ANPs, could effectively inhibit the metabolism and proliferation and promote the apoptosis of human pancreatic carcinoma (PANC-1) in vitro. Intravenous injection of 406-nm GEM-ANPs exhibited a significant increase of gemcitabine in the pancreas, liver, and spleen of Sprague–Dawley rats (p < 0.05). Moreover, no signs of toxic side effects analyzed by blood parameter changes were observed after 3 weeks of administration although a high dose (200 mg/kg) of GEM-ANPs were used. Additionally, in PANC-1-induced tumor mice, intravenous injection of 406-nm GEM-ANPs also could effectively reduce the tumor volume by comparison with free gemcitabine. With these findings, albumin nanosphere-loading approach might be efficacious to improve the antitumor activity of gemcitabine, and the efficacy is associated with the size of GEM-ANPs. PMID:23594566

  8. Formation of GEMS from shock-accelerated crystalline dust in Superbubbles

    SciTech Connect

    Westphal, A; Bradley, J P

    2004-12-08

    Interplanetary dust particles (IDPs) contain enigmatic sub-micron components called GEMS (Glass with Embedded Metal and Sulfides). The compositions and structures of GEMS indicate that they have been processed by exposure to ionizing radiation but details of the actual irradiation environment(s) have remained elusive. Here we propose a mechanism and astrophysical site for GEMS formation that explains for the first time the following key properties of GEMS; they are stoichiometrically enriched in oxygen and systematically depleted in S, Mg, Ca and Fe (relative to solar abundances), most have normal (solar) oxygen isotopic compositions, they exhibit a strikingly narrow size distribution (0.1-0.5 {micro}m diameter), and some of them contain ''relict'' crystals within their silicate glass matrices. We show that the compositions, size distribution, and survival of relict crystals are inconsistent with amorphization by particles accelerated by diffusive shock acceleration. Instead, we propose that GEMS are formed from crystalline grains that condense in stellar outflows from massive stars in OB associations, are accelerated in encounters with frequent supernova shocks inside the associated superbubble, and are implanted with atoms from the hot gas in the SB interior. We thus reverse the usual roles of target and projectile. Rather than being bombarded at rest by energetic ions, grains are accelerated and bombarded by a nearly monovelocity beam of atoms as viewed in their rest frame. Meyer, Drury and Ellison have proposed that galactic cosmic rays originate from ions sputtered from such accelerated dust grains. We suggest that GEMS are surviving members of a population of fast grains that constitute the long-sought source material for galactic cosmic rays. Thus, representatives of the GCR source material may have been awaiting discovery in cosmic dust labs for the last thirty years.

  9. Last glacial maximum constraints on the Earth System model HadGEM2-ES

    NASA Astrophysics Data System (ADS)

    Hopcroft, Peter O.; Valdes, Paul J.

    2015-09-01

    We investigate the response of the atmospheric and land surface components of the CMIP5/AR5 Earth System model HadGEM2-ES to pre-industrial (PI: AD 1860) and last glacial maximum (LGM: 21 kyr) boundary conditions. HadGEM2-ES comprises atmosphere, ocean and sea-ice components which are interactively coupled to representations of the carbon cycle, aerosols including mineral dust and tropospheric chemistry. In this study, we focus on the atmosphere-only model HadGEM2-A coupled to terrestrial carbon cycle and aerosol models. This configuration is forced with monthly sea surface temperature and sea-ice fields from equivalent coupled simulations with an older version of the Hadley Centre model, HadCM3. HadGEM2-A simulates extreme cooling over northern continents and nearly complete die back of vegetation in Asia, giving a poor representation of the LGM environment compared with reconstructions of surface temperatures and biome distributions. The model also performs significantly worse for the LGM in comparison with its precursor AR4 model HadCM3M2. Detailed analysis shows that the major factor behind the vegetation die off in HadGEM2-A is a subtle change to the temperature dependence of leaf mortality within the phenology model of HadGEM2. This impacts on both snow-vegetation albedo and vegetation dynamics. A new set of parameters is tested for both the pre-industrial and LGM, showing much improved coverage of vegetation in both time periods, including an improved representation of the needle-leaf forest coverage in Siberia for the pre-industrial. The new parameters and the resulting changes in global vegetation distribution strongly impact the simulated loading of mineral dust, an important aerosol for the LGM. The climate response in an abrupt 4× pre-industrial CO2 simulation is also analysed and shows modest regional impacts on surface temperatures across the Boreal zone.

  10. Solving spatial inverse problems using the probability perturbation method: An S-GEMS implementation

    NASA Astrophysics Data System (ADS)

    Li, Ting; Caers, Jef

    2008-09-01

    The probability perturbation method (PPM) is introduced as a flexible and efficient sampling technique for generating inverse solutions under a given prior geological constraint (prior model). In this paper, we present a methodology for producing software code that runs PPM within a public domain geostatistical software called the Stanford Geostatistical Earth Modeling Software (S-GEMS). The challenge in creating such code lies in the great diversity of forward models as well as prior models that can be handled by the PPM. Therefore, our software solution must be highly flexible and extensible such that it can be tailored to the various applications at hand. Our implementation has two main objectives: (1) to create an integrated working environment which provides users easy access to functionalities of the PPM through a general user interface as well as visualize results; (2) allow the users to plug-in their application specific code into the PPM algorithm workflow. We provide a two-part solution. The first part, which is hard-coded in S-GEMS as a plug-in module, runs the Dekker-Brent optimization algorithm to control the parameter perturbation needed for the inversion. It generates the PPM user interface and allows visualization of the spatial domain of interest using S-GEMS graphics capability. The second part is coded in object-oriented Python scripts and is used to control the PPM execution in S-GEMS. Users can program their particular needs in scripts and load them into S-GEMS as part of the PPM workflow. The same mechanism can be used to extend the capabilities of PPM itself by implementing new PPM variants in Python and making them a part of the base class hierarchy. Case studies are used to demonstrate the flexibility of our code. This approach requires the user to adapt only a small amount of python code, without modifying, or re-compiling the core S-GEMS code.

  11. An improved error assessment for the GEM-T1 gravitational model

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Marsh, J. G.; Klosko, S. M.; Pavlis, E. C.; Patel, G. B.; Chinn, D. S.; Wagner, C. A.

    1989-01-01

    Several tests were designed to determine the correct error variances for the GEM-T1 gravitational solution which was derived exclusively from satellite tracking data. The basic method employs both wholly independent and dependent subset data solutions and produces a full field coefficient by coefficient estimate of the model uncertainties. The GEM-T1 errors were further analyzed using a method based upon eigenvalue-eigenvector analysis which calibrates the entire covariance matrix. Dependent satellite and independent altimetric and surface gravity data sets, as well as independent satellite deep resonance information, confirm essentially the same error assessment.

  12. Chandra HETG Spectra of SS Cyg and U Gem in Quiescence and Outburst

    SciTech Connect

    Mauche, C W; Wheatley, P J; Long, K S; Raymond, J C; Szkody, P

    2004-09-24

    Chandra HETG spectra of the prototypical dwarf novae SS Cyg and U Gem in quiescence and outburst are presented and discussed. When SS Cyg goes into outburst, it becomes dimmer in hard X-rays and displays a dramatic shift in its relative line strengths, whereas when U Gem goes into outburst, it becomes brighter in hard X-rays and displays only a minor shift in its relative line strengths. In both systems, the emission lines become significantly broader in outburst, signaling the presence of high velocity gas either in Keplerian orbits around the white dwarf or flowing outward from the system.

  13. Metadata for selecting or submitting generic seismic vulnerability functions via GEM's vulnerability database

    USGS Publications Warehouse

    Jaiswal, Kishor

    2013-01-01

    This memo lays out a procedure for the GEM software to offer an available vulnerability function for any acceptable set of attributes that the user specifies for a particular building category. The memo also provides general guidelines on how to submit the vulnerability or fragility functions to the GEM vulnerability repository, stipulating which attributes modelers must provide so that their vulnerability or fragility functions can be queried appropriately by the vulnerability database. An important objective is to provide users guidance on limitations and applicability by providing the associated modeling assumptions and applicability of each vulnerability or fragility function.

  14. GEM detectors for WEST and potential application for heavy impurity transport studies

    NASA Astrophysics Data System (ADS)

    Mazon, D.; Jardin, A.; Coston, C.; Faisse, F.; Chernyshova, M.; Czarski, T.; Kasprowicz, G.; Wojenski, A.

    2016-08-01

    In tokamaks equipped with metallic walls and in particular tungsten, the interplay between particle transport and MagnetoHydroDynamic (MHD) activity might lead to impurities accumulation and finally to sudden plasma termination called disruption. Studying such transport phenomena is thus essential if stationary discharges are to be achieved. On WEST a new SXR diagnostic is developed in collaboration with IPPLM (Poland) and the Warsaw University of Technology, based on a triple Gas Electron Multiplier (GEM) detector. Potential application of the WEST GEM detectors for tomographic reconstruction and subsequent transport analysis is presented.

  15. GEM tracker for high luminosity experiments at the JLab Hall A

    SciTech Connect

    Bellini, Vincenzo G; Cisbani, Evaristo; Capogni, Marco; Colilli, Stephano P; De Leo, Raffaele A; De Oliveira, Denny M; De Smet, Fabienne; Fratoni, Rolando; Frullani, Salvatore; Giuliani, Fausto; Gricia, Massimo; Librizzi, F; Maurizio, Lucentini; Mammoliti, Francesco D; Minutoli, Saverio G; Musico, Paolo; Noto, Francesco; Perrino, Roberto; Santavenere, Fabio; Sutera, Concetta

    2012-05-01

    A new large-area, lightweight tracker based on the GEM technology is under development for the upcoming experiments in Hall A at Jefferson Lab, where a longitudinally polarized electron beam of 11 GeV will be available in late 2013. This beam, combined with innovative polarized targets, will provide luminosity up to 10{sup 39}/(s-cm{sup 2}) opening exciting opportunities to investigate unexplored aspects of the inner structure of the nucleon and the dynamics of its constituents. The GEM tracker design is presented in this paper.

  16. GEMGrid: a wafer post-processed GEM-like radiation detector

    NASA Astrophysics Data System (ADS)

    Blanco Carballo, V. M.; Bilevych, Y.; Chefdeville, M.; Fransen, M.; van der Graaf, H.; Salm, C.; Schmitz, J.; Timmermans, J.

    2009-09-01

    This paper presents a new wafer post-processed micropatterned gaseous radiation detector called GEMGrid. The device consists of a GEM-like structure fabricated with SU-8 photoresist directly on top of a Timepix chip with zero gap distance. The detector characteristics have been studied in several gas mixtures. The device is capable of tracking minimum ionizing particles and exhibits good energy resolution on 55Fe decays. We further show a strongly improved mechanical robustness of these GEM-like structures as compared to a pillar-supported integrated Micromegas.

  17. Divergent Mechanistic Routes for the Formation of gem-Dimethyl Groups in the Biosynthesis of Complex Polyketides

    SciTech Connect

    Poust, S; Phelan, RM; Deng, K; Katz, L; Petzold, CJ; Keasling, JD

    2015-01-07

    The gem-dimethyl groups in polyketide-derived natural products add steric bulk and, accordingly, lend increased stability to medicinal compounds, however, our ability to rationally incorporate this functional group in modified natural products is limited. In order to characterize the mechanism of gem-dimethyl group formation, with a goal toward engineering of novel compounds containing this moiety, the gem-dimethyl group producing polyketide synthase (PKS) modules of yersiniabactin and epothilone were characterized using mass spectrometry. The work demonstrated, contrary to the canonical understanding of reaction order in PKSs, that methylation can precede condensation in gem-dimethyl group producing PKS modules. Experiments showed that both PKSs are able to use dimethylmalonyl acyl carrier protein (ACP) as an extender unit. Interestingly, for epothilone module8, use of dimethylmalonyl-ACP appeared to be the sole route to form a gem-dimethylated product, while the yersiniabactin PKS could methylate before or after ketosynthase condensation.

  18. Optics in the Great Exploration in Math and Science (GEMS) program: a summary of effective pedagogical approaches

    NASA Astrophysics Data System (ADS)

    Pompea, Stephen M.; Gek, Tan K.

    2002-05-01

    This paper examines how optics is treated in instructional materials developed for the Great Explorations in Math and Science (GEMS) Program at the Lawrence Hall of Science, University of California, Berkeley. The GEMS program is a prominent resource for teachers in the United States and in many other countries. It represents a widely acknowledged, innovative approach to science and mathematics education. GEMS teacher's guides and handbooks offer a wide range of supplementary learning experiences for preschool through 8th grade (about age 13). Two guides already developed (Color Analyzers and More than Magnifiers) and one under development (working title: Invisible Universe) have a strong emphasis on fundamentals of optics. The organization and approaches of the guides will be described, with particular emphasis on the pedagogical approach represented. GEMS activities engage students in direct experience and experimentation in order to introduce essential, standards- based principles and concepts. Overwhelming educational evidence that students learn best by doing is the basis for the GEMS approach.

  19. Teaching ``The Physics of Energy'' at MIT

    NASA Astrophysics Data System (ADS)

    Jaffe, Robert

    2009-05-01

    New physics courses on energy are popping up at colleges and universities across the country. Many require little or no previous physics background, aiming to introduce a broad audience to this complex and critical problem, often augmenting the scientific message with economic and policy discussions. Others are advanced courses, focussing on highly specialized subjects like solar voltaics, nuclear physics, or thermal fluids, for example. About two years ago Washington Taylor and I undertook to develop a course on the ``Physics of Energy'' open to all MIT students who had taken MIT's common core of university level calculus, physics, and chemistry. By avoiding higher level prerequisites, we aimed to attract and make the subject relevant to students in the life sciences, economics, etc. --- as well as physical scientists and engineers --- who want to approach energy issues in a sophisticated and analytical fashion, exploiting their background in calculus, mechanics, and E & M, but without having to take advanced courses in thermodynamics, quantum mechanics, or nuclear physics beforehand. Our object was to interweave teaching the fundamental physics principles at the foundations of energy science with the applications of those principles to energy systems. We envisioned a course that would present the basics of statistical, quantum, and fluid mechanics at a fairly sophisticated level and apply those concepts to the study of energy sources, conversion, transport, losses, storage, conservation, and end use. In the end we developed almost all of the material for the course from scratch. The course debuted this past fall. I will describe what we learned and what general lessons our experience might have for others who contemplate teaching energy physics broadly to a technically sophisticated audience.

  20. OpenGeoSys-GEMS: Hybrid parallelization of a reactive transport code with MPI and threads

    NASA Astrophysics Data System (ADS)

    Kosakowski, G.; Kulik, D. A.; Shao, H.

    2012-04-01

    OpenGeoSys-GEMS is a generic purpose reactive transport code based on the operator splitting approach. The code couples the Finite-Element groundwater flow and multi-species transport modules of the OpenGeoSys (OGS) project (http://www.ufz.de/index.php?en=18345) with the GEM-Selektor research package to model thermodynamic equilibrium of aquatic (geo)chemical systems utilizing the Gibbs Energy Minimization approach (http://gems.web.psi.ch/). The combination of OGS and the GEM-Selektor kernel (GEMS3K) is highly flexible due to the object-oriented modular code structures and the well defined (memory based) data exchange modules. Like other reactive transport codes, the practical applicability of OGS-GEMS is often hampered by the long calculation time and large memory requirements. • For realistic geochemical systems which might include dozens of mineral phases and several (non-ideal) solid solutions the time needed to solve the chemical system with GEMS3K may increase exceptionally. • The codes are coupled in a sequential non-iterative loop. In order to keep the accuracy, the time step size is restricted. In combination with a fine spatial discretization the time step size may become very small which increases calculation times drastically even for small 1D problems. • The current version of OGS is not optimized for memory use and the MPI version of OGS does not distribute data between nodes. Even for moderately small 2D problems the number of MPI processes that fit into memory of up-to-date workstations or HPC hardware is limited. One strategy to overcome the above mentioned restrictions of OGS-GEMS is to parallelize the coupled code. For OGS a parallelized version already exists. It is based on a domain decomposition method implemented with MPI and provides a parallel solver for fluid and mass transport processes. In the coupled code, after solving fluid flow and solute transport, geochemical calculations are done in form of a central loop over all finite

  1. Stochastic noise characteristics in matrix inversion tomosynthesis (MITS).

    PubMed

    Godfrey, Devon J; McAdams, H P; Dobbins, James T Third

    2009-05-01

    Matrix inversion tomosynthesis (MITS) uses known imaging geometry and linear systems theory to deterministically separate in-plane detail from residual tomographic blur in a set of conventional tomosynthesis ("shift-and-add") planes. A previous investigation explored the effect of scan angle (ANG), number of projections (N), and number of reconstructed planes (NP) on the MITS impulse response and modulation transfer function characteristics, and concluded that ANG = 20 degrees, N = 71, and NP = 69 is the optimal MITS imaging technique for chest imaging on our prototype tomosynthesis system. This article examines the effect of ANG, N, and NP on the MITS exposure-normalized noise power spectra (ENNPS) and seeks to confirm that the imaging parameters selected previously by an analysis of the MITS impulse response also yield reasonable stochastic properties in MITS reconstructed planes. ENNPS curves were generated for experimentally acquired mean-subtracted projection images, conventional tomosynthesis planes, and MITS planes with varying combinations of the parameters ANG, N, and NP. Image data were collected using a prototype tomosynthesis system, with 11.4 cm acrylic placed near the image receptor to produce lung-equivalent beam hardening and scattered radiation. Ten identically acquired tomosynthesis data sets (realizations) were collected for each selected technique and used to generate ensemble mean images that were subtracted from individual image realizations prior to noise power spectra (NPS) estimation. NPS curves were normalized to account for differences in entrance exposure (as measured with an ion chamber), yielding estimates of the ENNPS for each technique. Results suggest that mid- and high-frequency noise in MITS planes is fairly equivalent in magnitude to noise in conventional tomosynthesis planes, but low-frequency noise is amplified in the most anterior and posterior reconstruction planes. Selecting the largest available number of projections (N

  2. Final Technical Report for the MIT Annular Fuel Research Project

    SciTech Connect

    Mujid S. Kazimi; Pavel Hejzlar

    2008-01-31

    MIT-NFC-PR-082 (January 2006) Abstract This summary provides an overview of the results of the U.S. DOE funded NERI (Nuclear Research ENergy Initiative) program on development of the internally and externally cooled annular fuel for high power density PWRs. This new fuel was proposed by MIT to allow a substantial increase in poer density (on the order of 30% or higher) while maintaining or improving safety margins. A comprehensive study was performed by a team consisting of MIT (lead organization), Westinghuse Electric Corporation, Gamma Engineering Corporation, Framatome ANP(formerly Duke Engineering) and Atomic Energy of Canada Limited.

  3. Unfälle mit motorisierten Zweirädern

    NASA Astrophysics Data System (ADS)

    Tschirschwitz, Christian

    Der Fahrer eines Pkw Opel Astra überquerte mit seinem Pkw von einer untergeordneten Einmündung kommend eine außerörtliche Bundesstraße in gerade Richtung. Dabei kam es zur Kollision mit einem sich von rechts vorfahrtsberechtigt annähernden Krad Suzuki RGV250. Der Anprall des Krades erfolgte mit dem Heck an die rechte Pkw-Flanke zwischen vorderem Radausschnitt und Fahrzeugecke. Der Krad-Fahrer, welcher sofort tot war und das Zweirad verklemmten sich am Pkw und verblieben relativ zu selbigem annähernd in Kollisionsstellung.

  4. Stochastic noise characteristics in matrix inversion tomosynthesis (MITS)

    SciTech Connect

    Godfrey, Devon J.; McAdams, H. P.; Dobbins, James T. III

    2009-05-15

    Matrix inversion tomosynthesis (MITS) uses known imaging geometry and linear systems theory to deterministically separate in-plane detail from residual tomographic blur in a set of conventional tomosynthesis (''shift-and-add'') planes. A previous investigation explored the effect of scan angle (ANG), number of projections (N), and number of reconstructed planes (NP) on the MITS impulse response and modulation transfer function characteristics, and concluded that ANG=20 deg., N=71, and NP=69 is the optimal MITS imaging technique for chest imaging on our prototype tomosynthesis system. This article examines the effect of ANG, N, and NP on the MITS exposure-normalized noise power spectra (ENNPS) and seeks to confirm that the imaging parameters selected previously by an analysis of the MITS impulse response also yield reasonable stochastic properties in MITS reconstructed planes. ENNPS curves were generated for experimentally acquired mean-subtracted projection images, conventional tomosynthesis planes, and MITS planes with varying combinations of the parameters ANG, N, and NP. Image data were collected using a prototype tomosynthesis system, with 11.4 cm acrylic placed near the image receptor to produce lung-equivalent beam hardening and scattered radiation. Ten identically acquired tomosynthesis data sets (realizations) were collected for each selected technique and used to generate ensemble mean images that were subtracted from individual image realizations prior to noise power spectra (NPS) estimation. NPS curves were normalized to account for differences in entrance exposure (as measured with an ion chamber), yielding estimates of the ENNPS for each technique. Results suggest that mid- and high-frequency noise in MITS planes is fairly equivalent in magnitude to noise in conventional tomosynthesis planes, but low-frequency noise is amplified in the most anterior and posterior reconstruction planes. Selecting the largest available number of projections (N=71) does

  5. Seasonal Dependence and Aging Effect of GEM Prototype for the SiD in the ILC

    NASA Astrophysics Data System (ADS)

    Ng, Yvonne; Yu, Jaehoon; White, Andrew; UTA Advance Detector Team

    2015-04-01

    High energy physics experiments require detectors and electronics that are capable of high precision, stable energy read out. Since 2007, the Advance Detector team in University of Texas at Arlington has been working on the Gas electron multiplier (GEM) detector technology. The detector technology utilizes the avalanche effect of charged particles in high electric field to magnify hadron signals produced in collision for precise and accurate energy interpretation. KPiX is a multi-channel 13 bits electronic chip designed for the time synchronous requirements of the Silicon Detector (SiD) in the International Linear Collider (ILC). The chip is coupled with GEM in this experiment to study the aging of the prototype 30cm × 30cm detector. In this study, cosmic ray is used as a source to study the gain fluctuation of GEM over a period of 3 years. Statistics methods are implemented to investigate the seasonal dependence of the gain of the signal. Also, the self-trigger mode of KPiX v.9 enable the study of the electronics though the chip's electronics gain variation. Results over 3 years shows that GEM is capable of stable data read out with little aging effect. The study provides invaluable information of the detector on its stability as a calorimeter.

  6. The Rainbow of Mathematics: A Great Explorations in Math and Science (GEMS) Handbook for Educators.

    ERIC Educational Resources Information Center

    Kopp, Jaine; Bergman, Lincoln

    This handbook features a presentation that summarizes the main ideas and current approaches in inquiry-based, content-rich mathematics education. This presentation is a product of Great Explorations in Math and Science (GEMS) professional development efforts, and has been used with teachers, administrators, parents, and at diverse community…

  7. Analysis of unscrammed loss of flow and heat sink for PRISM with GEM

    SciTech Connect

    Slovik, G.C.; Van Tuyle, G.J.; Kennett, R.J. )

    1991-01-01

    The US Department of Energy is sponsoring an advanced liquid-metal reactor design by General Electric Company (GE) called PRISM. The intent is to design a reactor with passively safe responses to many operational and severe accidents. PRISM is under review at the US Nuclear Regulatory Commission for licensability with Brookhaven National Laboratory providing technical assistance. Recently, the PRISM design has been modified to include three gas expansion modules (GEMs) on its core periphery. The GEMs were added to quickly reduce the power (by inserting negative reactivity) during loss-of-flow events to curtail peak fuel and clad temperatures predicted in the previous design. The GEM prototypes have been tested at the Fast Flux Test Facility. The significance of the GEMs in PRISM is discussed in this paper through the evaluation of the unprotected loss of flow (ULOF) and loss of heat sink using the SSC code. It has been demonstrated in the past that SSC predicts results similar to GE and other liquid-metal reactor codes.

  8. Stages of Psychometric Measure Development: The Example of the Generalized Expertise Measure (GEM)

    ERIC Educational Resources Information Center

    Germain, Marie-Line

    2006-01-01

    This paper chronicles the steps, methods, and presents hypothetical results of quantitative and qualitative studies being conducted to develop a Generalized Expertise Measure (GEM). Per Hinkin (1995), the stages of scale development are domain and item generation, content expert validation, and pilot test. Content/face validity and internal…

  9. An improved model of the Earth's gravity field - GEM-T3

    NASA Technical Reports Server (NTRS)

    Nerem, R. S.; Lerch, F. J.; Putney, B. H.; Klosko, S. M.; Patel, G. B.; Williamson, R. G.; Pavlis, E. C.

    1992-01-01

    An improved model of the Earth's gravitational field is developed from a combination of conventional satellite tracking, satellite altimeter measurements, and surface gravimetric data (GEM-T3). This model gives improved performance for the computation of satellite orbital effects as well as a superior representation of the geoid from that achieved in any previous Goddard Earth Model. The GEM-T3 model uses altimeter data directly to define the orbits, geoid, and dynamic height fields. Altimeter data acquired during the GEOS-3 (1975-1976), SEASAT (1978), and GEOSAT (1986-1987) missions were used to compute GEM-T3. In order to accommodate the non-gravitational signal mapped by these altimeters, spherical harmonic models of the dynamic height of the ocean surface were recovered for each mission simultaneously with the gravitational field. The tracking data utilized in the solution includes more than 1300 arcs of data encompassing 31 different satellites. The observational data base is highly dependent on SLR, but also includes TRANET Doppler, optical, S-Band average range-rate and satellite-to-satellite tracking acquired between ATS-6 and GEOS-3. The GEM-T3 model has undergone extensive error calibration.

  10. An improved error assessment for the GEM-T1 gravitational model

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Marsh, J. G.; Klosko, S. M.; Pavlis, E. C.; Patel, G. B.; Chinn, D. S.; Wagner, C. A.

    1988-01-01

    Several tests were designed to determine the correct error variances for the Goddard Earth Model (GEM)-T1 gravitational solution which was derived exclusively from satellite tracking data. The basic method employs both wholly independent and dependent subset data solutions and produces a full field coefficient estimate of the model uncertainties. The GEM-T1 errors were further analyzed using a method based upon eigenvalue-eigenvector analysis which calibrates the entire covariance matrix. Dependent satellite and independent altimetric and surface gravity data sets, as well as independent satellite deep resonance information, confirm essentially the same error assessment. These calibrations (utilizing each of the major data subsets within the solution) yield very stable calibration factors which vary by approximately 10 percent over the range of tests employed. Measurements of gravity anomalies obtained from altimetry were also used directly as observations to show that GEM-T1 is calibrated. The mathematical representation of the covariance error in the presence of unmodeled systematic error effects in the data is analyzed and an optimum weighting technique is developed for these conditions. This technique yields an internal self-calibration of the error model, a process which GEM-T1 is shown to approximate.

  11. A Measurement of the Scintillation Light Yield in CD4 Using a Photosensitive GEM Detector

    SciTech Connect

    Azmoun, B.; Azmoun, B.; Caccavano, A.; Rumore, M.; Sinsheimer, J.; Smirnov, N.; Stoll, S.; Woody, C.

    2010-08-01

    The absolute photon yield of scintillation light produced by highly ionizing particles in pure CF{sub 4} has been measured using a photosensitive Gas Electron Multiplier (GEM) detector. The detector consists of two standard GEMs and a CsI coated GEM which acts as a photocathode that is sensitive to the 160 nm scintillation light produced in CF{sub 4}. The light yield was determined in terms of the number of scintillation photons emitted into a 4{pi} solid angle produced per MeV of energy deposited in the gas by a 5.5 MeV alpha particle and found to be 314 {+-} 15 photons per MeV. The quantum yield was determined using a fitting method to determine the number of photoelectrons from the measured pulse height distribution, and by an independent method using the measured gain of the GEM detector. The effect of scintillation light in CF{sub 4} on the performance of Cherenkov detectors, such as the PHENIX Hadron Blind Detector (HBD) at RHIC, is also discussed.

  12. Insights & Outcomes: Assessments for Great Explorations in Math and Science. LHS GEMS.

    ERIC Educational Resources Information Center

    Barber, Jacqueline; And Others

    This handbook, part of the GEMS (Great Explorations in Math and Science) series, contains ready-made assessments for teachers to integrate within their presentation of activity-based mathematics and science units. The first main section of the book is called "Pearl's Journal: A Year in the Life of...." This fictitious teacher's journal is…

  13. Status report of the upgrade of the CMS muon system with Triple-GEM detectors

    NASA Astrophysics Data System (ADS)

    Abbaneo, D.; Abbas, M.; Abbrescia, M.; Abdelalim, A. A.; Abi Akl, M.; Aboamer, O.; Acosta, D.; Ahmad, A.; Ahmed, W.; Ahmed, W.; Aleksandrov, A.; Aly, R.; Altieri, P.; Asawatangtrakuldee, C.; Aspell, P.; Assran, Y.; Awan, I.; Bally, S.; Ban, Y.; Banerjee, S.; Barashko, V.; Barria, P.; Bencze, G.; Beni, N.; Benussi, L.; Bhopatkar, V.; Bianco, S.; Bos, J.; Bouhali, O.; Braghieri, A.; Braibant, S.; Buontempo, S.; Calabria, C.; Caponero, M.; Caputo, C.; Cassese, F.; Castaneda, A.; Cauwenbergh, S.; Cavallo, F. R.; Celik, A.; Choi, M.; Choi, S.; Christiansen, J.; Cimmino, A.; Colafranceschi, S.; Colaleo, A.; Conde Garcia, A.; Czellar, S.; Dabrowski, M. M.; De Lentdecker, G.; De Oliveira, R.; de Robertis, G.; Dildick, S.; Dorney, B.; Elmetenawee, W.; Endroczi, G.; Errico, F.; Fenyvesi, A.; Ferry, S.; Furic, I.; Giacomelli, P.; Gilmore, J.; Golovtsov, V.; Guiducci, L.; Guilloux, F.; Gutierrez, A.; Hadjiiska, R. M.; Hassan, A.; Hauser, J.; Hoepfner, K.; Hohlmann, M.; Hoorani, H.; Iaydjiev, P.; Jeng, Y. G.; Kamon, T.; Karchin, P.; Korytov, A.; Krutelyov, S.; Kumar, A.; Kim, H.; Lee, J.; Lenzi, T.; Litov, L.; Loddo, F.; Madorsky, A.; Maerschalk, T.; Maggi, M.; Magnani, A.; Mal, P. K.; Mandal, K.; Marchioro, A.; Marinov, A.; Masod, R.; Majumdar, N.; Merlin, J. A.; Mitselmakher, G.; Mohanty, A. K.; Mohamed, S.; Mohapatra, A.; Molnar, J.; Muhammad, S.; Mukhopadhyay, S.; Naimuddin, M.; Nuzzo, S.; Oliveri, E.; Pant, L. M.; Paolucci, P.; Park, I.; Passeggio, G.; Pavlov, B.; Philipps, B.; Piccolo, D.; Postema, H.; Puig Baranac, A.; Radi, A.; Radogna, R.; Raffone, G.; Ranieri, A.; Rashevski, G.; Riccardi, C.; Rodozov, M.; Rodrigues, A.; Ropelewski, L.; RoyChowdhury, S.; Ryu, G.; Ryu, M. S.; Safonov, A.; Salva, S.; Saviano, G.; Sharma, A.; Sharma, A.; Sharma, R.; Shah, A. H.; Shopova, M.; Sturdy, J.; Sultanov, G.; Swain, S. K.; Szillasi, Z.; Talvitie, J.; Tatarinov, A.; Tuuva, T.; Tytgat, M.; Vai, I.; Van Stenis, M.; Venditti, R.; Verhagen, E.; Verwilligen, P.; Vitulo, P.; Volkov, S.; Vorobyev, A.; Wang, D.; Wang, M.; Yang, U.; Yang, Y.; Yonamine, R.; Zaganidis, N.; Zenoni, F.; Zhang, A.

    2016-07-01

    For the High Luminosity LHC CMS is planning to install new large size Triple-GEM detectors, equipped with a new readout system in the forward region of its muon system (1.5 < | η | < 2.2). In this note we report on the status of the project, the main achievements regarding the detectors as well as the electronics and readout system.

  14. COMBINING ECOPHYSIOLOGICAL MODELS AND GENOMICS TO DECIPHER THE GEM-TO-P PROBLEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Much of agricultural research has the ultimate goal of enhancing our ability to predict phenotypes (P) based upon knowledge of genotypes (G), environment (E) and management (M) in order to quantitatively predict phenotypes (P), also known as the GEM-to-P problem. Ecophysiological models are powerful...

  15. Characterization of Large GEM Module for the Tracker at Jlab Hall A

    NASA Astrophysics Data System (ADS)

    Mammoliti, F.; Bellin, V.; Cisbani, E.; Librizzi, F.; Musico, P.; Noto, F.; Perrino, R.; Re, L.; Sutera, M. C.

    2015-06-01

    A new Large-Acceptance Forward Angle Spectrometer (Super BigBite) is under development at JLab/Hall A for the upcoming experiments in Hall A at Jefferson Lab where a longitudinally polarized electron beam of 11 GeV is now available. This beam, combined with innovative polarized targets will provided luminosity up to 1039/(s·cm2) opening exciting opportunities to investigate unexplored aspects of the inner structure of the nucleon. The tracker of this new apparatus is based on the Gas Electron Multiplier (GEM) technology, which has been chosen to optimize cost/performance, position resolution and to meet the high hit rate (>1 MHz/cm2). The first GEM detector modules, designed and built by the INFN Collaboration JLAB12, were tested at the DESY test beam facility in Hamburg, by using an electron beam with energy ranging from 2.0 to 6.0 GeV. In particular, three 40x50 cm2 GEM chambers were equipped with a new implementation of the APV25 readout chip. Measurements were performed at different impact points and angles between the electron beam and the plane of the GEM chambers, with one large chamber in a solenoid magnetic field up to 500 Gauss. In this paper we present the technical features of the tracker and comment on the presently achieved performance.

  16. Experiential Engineering through iGEM--An Undergraduate Summer Competition in Synthetic Biology

    ERIC Educational Resources Information Center

    Mitchell, Rudolph; Dori, Yehudit Judy; Kuldell, Natalie H.

    2011-01-01

    Unlike students in other engineering disciplines, undergraduates in biological engineering typically have limited opportunity to develop design competencies, and even fewer chances to implement their designed projects. The international Genetically Engineered Machines (iGEM) competition is a student Synthetic Biology competition that, in 2009,…

  17. Evaluation of the GEM-AQ model in the context of the AQMEII Phase 1 project

    NASA Astrophysics Data System (ADS)

    Struzewska, J.; Zdunek, M.; Kaminski, J. W.; Łobocki, L.; Porebska, M.; Jefimow, M.; Gawuc, L.

    2015-04-01

    In the scope of the AQMEII Phase 1 project the GEM-AQ model was run over Europe for the year 2006. The modelling domain was defined using a global variable resolution grid with a rotated equator and uniform resolution of 0.2° × 0.2° over the European continent. Spatial distribution and temporal variability of the GEM-AQ model results were analysed for surface ozone and PM10 concentrations. Model results were compared with measurements available in the ENSEMBLE database. Statistical measures were used to evaluate performance of the GEM-AQ model. The mean bias error, the mean absolute gross error and the Pearson correlation coefficient were calculated for the maximum 8 h running average ozone concentrations and daily mean PM10 concentrations. The GEM-AQ model performance was characterized for station types, European climatic regions and seasons. The best performance for ozone was obtained at suburban stations, and the worst performance was obtained for rural stations where the model tends to underestimate. The best results for PM10 were calculated for urban stations, while over most of Europe concentrations at rural sites were too high. Discrepancies between modelled and observed concentrations were discussed in the context of emission data uncertainty as well as the impact of large-scale dynamics and circulation of air masses. Presented analyses suggest that interpretation of modelling results is enhanced when regional climate characteristics are taken into consideration.

  18. Evaluation of the GEM-AQ model in the context of the AQMEII Phase 1 project

    NASA Astrophysics Data System (ADS)

    Struzewska, J.; Zdunek, M.; Kaminski, J. W.; Lobocki, L.; Porebska, M.; Jefimow, M.; Gawuc, L.

    2015-01-01

    In the scope of the AQMEII Phase 1 project the GEM-AQ model was run over Europe for the year 2006. The modelling domain was defined using a global variable resolution grid with a rotated equator and uniform resolution of 0.2° × 0.2° over the European continent. Spatial distribution and temporal variability of the GEM-AQ model results were analysed for surface ozone and PM10 concentrations. Model results were compared with measurements available in the ENSEMBLE database. Statistical measures were used to evaluate performance of the GEM-AQ model. The mean bias error, the mean absolute gross error and the Pearson correlation coefficient were calculated for the maximum 8 h running average ozone concentrations and daily mean PM10 concentrations. The GEM-AQ model performance was characterised for station types, European climatic regions, and seasons. The best performance for ozone was obtained at suburban stations and the worst performance was obtained for rural stations where the model tends to underestimate. The best results for PM10 were calculated for urban stations, while over most of Europe concentrations at rural sites were too high. Discrepancies between modelled and observed concentrations were discussed in the context of emission data uncertainty as well as the impact of large scale dynamics and circulation of air masses. Presented analyses suggest that interpretation of modelling results is enhanced when regional climate characteristics are ta ken into consideration.

  19. Radiation environment and shielding for the GEM experiment at the SSC

    SciTech Connect

    Diwan, M.; Fisyak, Y.; Mokhov, N.

    1993-07-01

    We have performed a comprehensive study of the radiation environment for the proposed GEM detector at the SSC. As a result of this study, we have developed a shielding scenario that will ensure that the detector will operate with its design performance for at least 10 years at the luminosity of 10{sup 33} cm{sup {minus}2}s{sup {minus}1}.

  20. Radiation environment and shielding for the GEM experiment at the SSC

    SciTech Connect

    Diwan, M.; Fisyak, Y.; Mokhov, N.

    1993-08-16

    We have performed a comprehensive study of the radiation environment for the proposed GEM detector at the SSC. As a result of this study, we have developed a shielding scenario that will ensure that the detector will operate with its design performance for at least 10 years at the luminosity of 10{sup 33} cm {sup {minus}2}{sub s}{sup {minus}1}.

  1. Development and Test of a GEM-Based TEPC System for In-Phantom Dose Measurements

    SciTech Connect

    C-K Chris Wang

    2007-03-13

    The objectives of this project include: (1) to construct a minature tissue equivalent proportional counter (TEPC) using a gas-electron-multiplier (GEM) foil, and (2) to conduct neutron and gamma-ray dose measurements with the detector embedded in a phantom

  2. Promoting microbiology education through the iGEM synthetic biology competition.

    PubMed

    Kelwick, Richard; Bowater, Laura; Yeoman, Kay H; Bowater, Richard P

    2015-08-01

    Synthetic biology has developed rapidly in the 21st century. It covers a range of scientific disciplines that incorporate principles from engineering to take advantage of and improve biological systems, often applied to specific problems. Methods important in this subject area include the systematic design and testing of biological systems and, here, we describe how synthetic biology projects frequently develop microbiology skills and education. Synthetic biology research has huge potential in biotechnology and medicine, which brings important ethical and moral issues to address, offering learning opportunities about the wider impact of microbiological research. Synthetic biology projects have developed into wide-ranging training and educational experiences through iGEM, the International Genetically Engineered Machines competition. Elements of the competition are judged against specific criteria and teams can win medals and prizes across several categories. Collaboration is an important element of iGEM, and all DNA constructs synthesized by iGEM teams are made available to all researchers through the Registry for Standard Biological Parts. An overview of microbiological developments in the iGEM competition is provided. This review is targeted at educators that focus on microbiology and synthetic biology, but will also be of value to undergraduate and postgraduate students with an interest in this exciting subject area. PMID:26260156

  3. GEM: Using Metadata to Enhance Internet Retrieval by K-12 Teachers.

    ERIC Educational Resources Information Center

    Sutton, Stuart A.; Oh, Sam G.

    1997-01-01

    Describes the GEM (Gateway to Educational Materials) project being developed to provide enhanced access to lesson plans and other Internet-based educational materials through metadata. Highlights include controlled vocabularies; NIDR (networked information discovery and retrieval); the Dublin Core element set; syntax; prototype interfaces; and…

  4. Evaluation of elite GEM inbred lines for multiple ear and kernel pest resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ear-colonizing insects and diseases are critical impediments for corn production in the southern US. These pests not only reduce yield but also impose health threat by mycotoxin contamination of human food and animal feed. The Germplasm Enhancement of Maize (GEM) Project is collaborative effort of...

  5. Evaluation of Exotic Temperate Accessions and Release of Introgressed Germplasm from the GEM Project

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Germplasm Enhancement of Maize Project (GEM) is a cooperative effort of the USDA-ARS, land grant universities, private industry, international, and non-governmental organizations to broaden the germplasm base of maize. Top cross performance of exotic temperate maize accessions identified germpla...

  6. A geopotential model from satellite tracking, altimeter, and surface gravity data: GEM-T3

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Nerem, R. S.; Putney, B. H.; Felsentreger, T. L.; Sanchez, B. V.; Marshall, J. A.; Klosko, S. M.; Patel, G. B.; Williamson, R. G.; Chinn, D. S.

    1994-01-01

    An improved model of Earth's gravitational field, Goddard Earth Model T-3 (GEM-T3), has been developed from a combination of satellite tracking, satellite altimeter, and surface gravimetric data. GEM-T3 provides a significant improvement in the modeling of the gravity field at half wavelengths of 400 km and longer. This model, complete to degree and order 50, yields more accurate satellite orbits and an improved geoid representation than previous Goddard Earth Models. GEM-T3 uses altimeter data from GEOS 3 (1975-1976), Seasat (1978) and Geosat (1986-1987). Tracking information used in the solution includes more than 1300 arcs of data encompassing 31 different satellites. The recovery of the long-wavelength components of the solution relies mostly on highly precise satellite laser ranging (SLR) data, but also includes Tracking Network (TRANET) Doppler, optical, and satellite-to-satellite tracking acquired between the ATS 6 and GEOS 3 satellites. The main advances over GEM-T2 (beyond the inclusion of altimeter and surface gravity information which is essential for the resolution of the shorter wavelength geoid) are some improved tracking data analysis approaches and additional SLR data. Although the use of altimeter data has greatly enhanced the modeling of the ocean geoid between 65 deg N and 60 deg S latitudes in GEM-T3, the lack of accurate detailed surface gravimetry leaves poor geoid resolution over many continental regions of great tectonic interest (e.g., Himalayas, Andes). Estimates of polar motion, tracking station coordinates, and long-wavelength ocean tidal terms were also made (accounting for 6330 parameters). GEM-T3 has undergone error calibration using a technique based on subset solutions to produce reliable error estimates. The calibration is based on the condition that the expected mean square deviation of a subset gravity solution from the full set values is predicted by the solutions' error covariances. Data weights are iteratively adjusted until

  7. Open source large-scale high-resolution environmental modelling with GEMS

    NASA Astrophysics Data System (ADS)

    Baarsma, Rein; Alberti, Koko; Marra, Wouter; Karssenberg, Derek

    2016-04-01

    Many environmental, topographic and climate data sets are freely available at a global scale, creating the opportunities to run environmental models for every location on Earth. Collection of the data necessary to do this and the consequent conversion into a useful format is very demanding however, not to mention the computational demand of a model itself. We developed GEMS (Global Environmental Modelling System), an online application to run environmental models on various scales directly in your browser and share the results with other researchers. GEMS is open-source and uses open-source platforms including Flask, Leaflet, GDAL, MapServer and the PCRaster-Python modelling framework to process spatio-temporal models in real time. With GEMS, users can write, run, and visualize the results of dynamic PCRaster-Python models in a browser. GEMS uses freely available global data to feed the models, and automatically converts the data to the relevant model extent and data format. Currently available data includes the SRTM elevation model, a selection of monthly vegetation data from MODIS, land use classifications from GlobCover, historical climate data from WorldClim, HWSD soil information from WorldGrids, population density from SEDAC and near real-time weather forecasts, most with a ±100m resolution. Furthermore, users can add other or their own datasets using a web coverage service or a custom data provider script. With easy access to a wide range of base datasets and without the data preparation that is usually necessary to run environmental models, building and running a model becomes a matter hours. Furthermore, it is easy to share the resulting maps, timeseries data or model scenarios with other researchers through a web mapping service (WMS). GEMS can be used to provide open access to model results. Additionally, environmental models in GEMS can be employed by users with no extensive experience with writing code, which is for example valuable for using models

  8. ISC-GEM: Global Instrumental Earthquake Catalogue (1900-2009) I. Location and Seismicity Patterns

    NASA Astrophysics Data System (ADS)

    Bondar, I.; Engdahl, E. R.; Villasenor, A.; Storchak, D. A.

    2012-12-01

    We present the final results of a two-year project sponsored by the GEM (Global Earthquake Model) Foundation. The ISC-GEM global catalogue consists of some 19 thousand instrumentally recorded, moderate to large earthquakes, spanning 110 years of seismicity. We relocated all events in the catalogue using a two-tier approach. The EHB location methodology (Engdahl et al., 1998) was applied first to obtain improved hypocentres with special focus on the depth determination. The locations were further refined in the next step by fixing the depths to those from the EHB analysis and applying the new ISC location algorithm (Bondár and Storchak, 2011) that reduces location bias by accounting for correlated travel-time prediction error structure. To facilitate the relocation effort, some 900,000 seismic P and S wave arrival-time data were added to the ISC database for the period between 1904 and 1963, either from original station bulletins in the ISC archive or by digitizing the scanned images of the ISS bulletin (Villaseñor and Engdahl, 2005; 2007). Although no substantial amount of new phase data were acquired for the modern period (1964-2009), the number of phases used in the location has still increased by 3 million, owing to fact that both the EHB and ISC locators use all ak135 (Kennett et al., 1995) phases in the location. We show that the relocation effort yielded substantially improved locations, especially in the first half of the 20th century; we demonstrate significant improvements in focal depth estimates in subduction zones and other seismically active regions; and we show that the ISC-GEM catalogue provides an improved view of 110 years of global seismicity of the Earth. The ISC-GEM Global Instrumental Earthquake Catalogue represents the final product of one of the ten global components in the GEM program, and will be made available to researchers at the ISC (www.isc.ac.uk) website.

  9. Modelling present and future African climate using CMIP5scenarios in HadGEM2-ES

    NASA Astrophysics Data System (ADS)

    Shimizu, M. H.; Diallo, M.; Dike, V. N.

    2014-12-01

    The present precipitation and temperature patterns and expected future changes (2073-2098) in Africa are investigated using the Hadley Centre Global Environmental Model 2-Earth System (HadGEM2-ES) under the fifth phase of the Coupled Model Intercomparison Project (CMIP5) protocols for historical and future emission scenarios simulations.In a CMIP5 multimodel analysis, the annual cycles of temperature and precipitation simulated by HadGEM2-ES were very close to the multimodel ensemble mean. HadGEM2-ES temperature simulation compares well with the National Center for Atmospheric Research (NCAR) reanalysis over the 1979-2004 periods, except for a summer overestimation in Central Africa, and a winter underestimation in tropical West Africa. The precipitation simulation compared well with the Global Precipitation Climatology Project (GPCP) data from 1979 to 2004 over the entire Africa, except in the Intertropical Convergence Zone (ITCZ), where the model fails to capture adequately the transition phase of the monsoon circulation. The dry regimes over Northern Africa as well as the wetter regime occurring over Central Africa, which is mainly regulated by the ITCZ displacement, and during the austral summer of Southern Africa, are also fairly reproduced by the HadGEM2-ES model. The model projects for the end of the 21st century a rainy South Africa, a change of the flood/drought cycle in the Tropics and a warming over the whole continent, varying from 3 to 7 ∘ C. HadGEM2-ES performance for Nigeria shows good reproduction of precipitation seasonal cycles for some locations, outside the ITCZ. However, the comparison with in situ measurement in Ilorin and Lagos shows the model is not being able to reproduce the precipitation annual cycle. Future projections for Nigeria exhibit warming everywhere and an enhancement of precipitation, especially in the northern part of the country.

  10. Review of recent work on MPD thrusters at MIT

    NASA Technical Reports Server (NTRS)

    Hastings, Daniel

    1992-01-01

    The topics are presented in viewgraph form and include the following: basic philosophy of MIT SSPL work; 2-D numerical magnetoplasmadynamic (MPD) simulations; analysis of MPD boundary layers; and ignition of MPD thrusters.

  11. MIT gets good marks for fighting gender discrimination

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2011-05-01

    The Massachusetts Institute of Technology (MIT) has made "significant progress" in increasing the number of female faculty members, with their numbers in science and engineering almost doubling over the last decade.

  12. MIT ASTROMAG 1.7 meter disk magnet design report

    NASA Technical Reports Server (NTRS)

    Marston, P. G.; Hale, J. R.; Vieira, R.; Zhukovsky, A.; Titus, P. H.; Sullivan, J. D.; Dawson, A. M.

    1990-01-01

    MIT has proposed a magnet design for ASTROMAG, which has demonstrated substantial improvement in performance as compared with the present HEAO baseline design. Several advantages of the MIT disk design are listed along with design characteristics. Details of field contours and active field regions are shown along with comparisons with other designs. Three alternative design configurations for the ASTROMAG disk coils are summarized. The parameters of the conductors are listed and basic parameters for each of the complete systems are shown.

  13. Simulation of the West African monsoon onset using the HadGEM3-RA regional climate model

    NASA Astrophysics Data System (ADS)

    Diallo, Ismaïla; Bain, Caroline L.; Gaye, Amadou T.; Moufouma-Okia, Wilfran; Niang, Coumba; Dieng, Mame D. B.; Graham, Richard

    2014-08-01

    The performance of the Hadley Centre Global Environmental Model version 3 regional climate model (HadGEM3-RA) in simulating the West African monsoon (WAM) is investigated. We focus on performance for monsoon onset timing and for rainfall totals over the June-July-August (JJA) season and on the model's representation of the underlying dynamical processes. Experiments are driven by the ERA-Interim reanalysis and follow the CORDEX experimental protocol. Simulations with the HadGEM3 global model, which shares a common physical formulation with HadGEM3-RA, are used to gain insight into the causes of HadGEM3-RA simulation errors. It is found that HadGEM3-RA simulations of monsoon onset timing are realistic, with an error in mean onset date of two pentads. However, the model has a dry bias over the Sahel during JJA of 15-20 %. Analysis suggests that this is related to errors in the positioning of the Saharan heat low, which is too far south in HadGEM3-RA and associated with an insufficient northward reach of the south-westerly low-level monsoon flow and weaker moisture convergence over the Sahel. Despite these biases HadGEM3-RA's representation of the general rainfall distribution during the WAM appears superior to that of ERA-Interim when using Global Precipitation Climatology Project or Tropical Rain Measurement Mission data as reference. This suggests that the associated dynamical features seen in HadGEM3-RA can complement the physical picture available from ERA-Interim. This approach is supported by the fact that the global HadGEM3 model generates realistic simulations of the WAM without the benefit of pseudo-observational forcing at the lateral boundaries; suggesting that the physical formulation shared with HadGEM3-RA, is able to represent the driving processes. HadGEM3-RA simulations confirm previous findings that the main rainfall peak near 10°N during June-August is maintained by a region of mid-tropospheric ascent located, latitudinally, between the cores of

  14. Large size GEM for Super Bigbite Spectrometer (SBS) polarimeter for Hall A 12GeV program at JLab

    SciTech Connect

    Gnanvo, Kondo; Liyanage, Nilanga; Nelyubin, Vladimir; Saenboonruang, Kiadtisak; Sacher, Seth; Wojtsekhowski, Bogdan

    2015-05-01

    We report on the R&D effort in the design and construction of a large size GEM chamber for the Proton Polarimeter of the Super Bigbite Spectrometer (SBS) in Hall A at Thomas Jefferson National Laboratory (JLab). The SBS Polarimeter trackers consist of two sets of four large chambers of size 200 cm x 60 cm2. Each chamber is a vertical stack of four GEM modules with an active area of 60 cm x 50 cm. We have built and tested several GEM modules and we describe in this paper the design and construction of the final GEM as well as the preliminary results on performances from tests carried out in our detector lab and with test beams at (Fermilab).

  15. Progress on the realization of a new GEM based neutron diagnostic concept for high flux neutron beams

    SciTech Connect

    Croci, G.; Tardocchi, M.; Rebai, M.; Cippo, E. Perelli; Gorini, G.; Cazzaniga, C.; Palma, M. Dalla; Pasqualotto, R.; Tollin, M.; Grosso, G.; Muraro, A.; Murtas, F.; Claps, G.; Cavenago, M.

    2014-08-21

    Fusion reactors will need high flux neutron detectors to diagnose the deuterium-deuterium and deuterium-tritium. A candidate detection technique is the Gas Electron Multiplier (GEM). New GEM based detectors are being developed for application to a neutral deuterium beam test facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission due to interaction of the deuterium beam with the deuterons implanted in the beam dump surface. This is done by placing a detector in close contact, right behind the dump. CNESM uses nGEM detectors, i.e. GEM detectors equipped with a cathode that also serves as neutron-proton converter foil. After the realization and test of several small area prototypes, a full size prototype has been realized and tested with laboratory sources. Test on neutron beams are foreseen for the next months.

  16. Progress on the realization of a new GEM based neutron diagnostic concept for high flux neutron beams

    NASA Astrophysics Data System (ADS)

    Croci, G.; Rebai, M.; Cazzaniga, C.; Palma, M. Dalla; Grosso, G.; Muraro, A.; Murtas, F.; Claps, G.; Pasqualotto, R.; Cippo, E. Perelli; Tardocchi, M.; Tollin, M.; Cavenago, M.; Gorini, G.

    2014-08-01

    Fusion reactors will need high flux neutron detectors to diagnose the deuterium-deuterium and deuterium-tritium. A candidate detection technique is the Gas Electron Multiplier (GEM). New GEM based detectors are being developed for application to a neutral deuterium beam test facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission due to interaction of the deuterium beam with the deuterons implanted in the beam dump surface. This is done by placing a detector in close contact, right behind the dump. CNESM uses nGEM detectors, i.e. GEM detectors equipped with a cathode that also serves as neutron-proton converter foil. After the realization and test of several small area prototypes, a full size prototype has been realized and tested with laboratory sources. Test on neutron beams are foreseen for the next months.

  17. Large size GEM for Super Bigbite Spectrometer (SBS) polarimeter for Hall A 12GeV program at JLab

    DOE PAGESBeta

    Gnanvo, Kondo; Liyanage, Nilanga; Nelyubin, Vladimir; Saenboonruang, Kiadtisak; Sacher, Seth; Wojtsekhowski, Bogdan

    2015-05-01

    We report on the R&D effort in the design and construction of a large size GEM chamber for the Proton Polarimeter of the Super Bigbite Spectrometer (SBS) in Hall A at Thomas Jefferson National Laboratory (JLab). The SBS Polarimeter trackers consist of two sets of four large chambers of size 200 cm x 60 cm2. Each chamber is a vertical stack of four GEM modules with an active area of 60 cm x 50 cm. We have built and tested several GEM modules and we describe in this paper the design and construction of the final GEM as well asmore » the preliminary results on performances from tests carried out in our detector lab and with test beams at (Fermilab).« less

  18. Verification of the accuracy of GEM-L2 in response to criticism by Lambeck and Coleman

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.

    1984-01-01

    The objective was to evaluate the accuracy of the Goddard Earth Model (GEM)-L2 and its improvement in estimating Lageos orbits in order to provide better baselines for plate tectonics, improved polar motion and Earth rotation. Analyses and comparisons with other models are made to verify accuracy in contrast to the Lambeck and Coleman result which denied the authors' accuracy estimates. The analysis presented completely verifies the accuracy of the GEM-L2 model and disproves the statistical methods of Lambeck and Coleman rejecting the accuracy of GEM-L2 as published in their report. The baselines derived from Lageos with GEM-L2 were estimated to have a 2 cm uncertainty due to the errors in the GEM-L2 gravity model which is supported by the results given. The calibration tests indicate that the errors in GEM-L2 should be reduced by about 30 percent which is in the opposite direction to the result obtained by Lambeck and Coleman.

  19. Reduction experiment of FeO-bearing amorphous silicate: application to origin of metallic iron in GEMS

    SciTech Connect

    Matsuno, Junya; Tsuchiyama, Akira; Miyake, Akira; Noguchi, Ryo; Ichikawa, Satoshi

    2014-09-10

    Glass with embedded metal and sulfides (GEMS) are amorphous silicates included in anhydrous interplanetary dust particles (IDPs) and can provide information about material evolution in our early solar system. Several formation processes for GEMS have been proposed so far, but these theories are still being debated. To investigate a possible GEMS origin by reduction of interstellar silicates, we synthesized amorphous silicates with a mean GEMS composition and performed heating experiments in a reducing atmosphere. FeO-bearing amorphous silicates were heated at 923 K and 973 K for 3 hr, and at 1023 K for 1-48 hr at ambient pressure in a reducing atmosphere. Fe grains formed at the interface between the silicate and the reducing gas through a reduction. In contrast, TEM observations of natural GEMS show that metallic grains are uniformly embedded in amorphous silicates. Therefore, the present study suggests that metallic inclusions in GEMS could not form as reduction products and that other formation process such as condensation or irradiation are more likely.

  20. First measurements with new high-resolution gadolinium-GEM neutron detectors

    NASA Astrophysics Data System (ADS)

    Pfeiffer, D.; Resnati, F.; Birch, J.; Etxegarai, M.; Hall-Wilton, R.; Höglund, C.; Hultman, L.; Llamas-Jansa, I.; Oliveri, E.; Oksanen, E.; Robinson, L.; Ropelewski, L.; Schmidt, S.; Streli, C.; Thuiner, P.

    2016-05-01

    European Spallation Source instruments like the macromolecular diffractometer (NMX) require an excellent neutron detection efficiency, high-rate capabilities, time resolution, and an unprecedented spatial resolution in the order of a few hundred micrometers over a wide angular range of the incoming neutrons. For these instruments solid converters in combination with Micro Pattern Gaseous Detectors (MPGDs) are a promising option. A GEM detector with gadolinium converter was tested on a cold neutron beam at the IFE research reactor in Norway. The μTPC analysis, proven to improve the spatial resolution in the case of 10B converters, is extended to gadolinium based detectors. For the first time, a Gd-GEM was successfully operated to detect neutrons with a measured efficiency of 11.8% at a wavelength of 2 Åand a position resolution better than 250 μm.

  1. Optical readout of a triple-GEM detector by means of a CMOS sensor

    NASA Astrophysics Data System (ADS)

    Marafini, M.; Patera, V.; Pinci, D.; Sarti, A.; Sciubba, A.; Spiriti, E.

    2016-07-01

    In last years, the development of optical sensors has produced objects able to provide very interesting performance. Large granularity is offered along with a very high sensitivity. CMOS sensors with millions of pixels able to detect as few as two or three photons per pixel are commercially available and can be used to read-out the optical signals provided by tracking particle detectors. In this work the results obtained by optically reading-out a triple-GEM detector by a commercial CMOS sensor will be presented. A standard detector was assembled with a transparent window below the third GEM allowing the light to get out. The detector is supplied with an Ar/CF4 based gas mixture producing 650 nm wavelength photons matching the maximum quantum efficiency of the sensor.

  2. GEM detector development for tokamak plasma radiation diagnostics: SXR poloidal tomography

    NASA Astrophysics Data System (ADS)

    Chernyshova, Maryna; Malinowski, Karol; Ziółkowski, Adam; Kowalska-Strzeciwilk, Ewa; Czarski, Tomasz; Poźniak, Krzysztof T.; Kasprowicz, Grzegorz; Zabołotny, Wojciech; Wojeński, Andrzej; Kolasiński, Piotr; Krawczyk, Rafał D.

    2015-09-01

    An increased attention to tungsten material is related to a fact that it became a main candidate for the plasma facing material in ITER and future fusion reactor. The proposed work refers to the studies of W influence on the plasma performances by developing new detectors based on Gas Electron Multiplier GEM) technology for tomographic studies of tungsten transport in ITER-oriented tokamaks, e.g. WEST project. It presents current stage of design and developing of cylindrically bent SXR GEM detector construction for horizontal port implementation. Concept to overcome an influence of constraints on vertical port has been also presented. It is expected that the detecting unit under development, when implemented, will add to the safe operation of tokamak bringing creation of sustainable nuclear fusion reactors a step closer.

  3. Non-uniformity effects of the inter-foil distance on GEM detector performance

    NASA Astrophysics Data System (ADS)

    Yan, Huang; Han, YI; Zhi-Gang, Xiao; Zhao, Zhang; Wen-Jing, Cheng; Li-Ming, Lü; Wei-Hua, Yan; Ren-Sheng, Wang; Hong-Jie, Li; Yan, Zhang; Li-Min, Duan; Rong-Jiang, Hu; Chen-Gui, Lu; He-Run, Yang; Peng, Ma; Hai-Yan, Gao

    2016-04-01

    The non-uniformity effect of the inter-foil distance has been studied using a gaseous electron multiplication (GEM) detector with sensitive area of 50mm × 50mm. A gradient of the inter-foil distance is introduced by using spacers with different heights at the two ends of the foil gap. While the cluster size and the intrinsic spatial resolution show insignificant dependence on the inter-foil distance, the gain exhibits an approximately linear dependence on the inter-foil distance. From the slope, a quantitative relationship between the change of the inter-foil distance and the change of the gain is derived, which can be used as a method to evaluate the non-uniformity of the foil gap in the application of large-area GEM detectors. Supported by National Natural Science Foundation of China (11375094, U1332207, 11120101004), and by Tsinghua University Initiative Scientific Research Program

  4. An EUV Study of the Eclipsing M-Dwarf Binary System YY GEM

    NASA Technical Reports Server (NTRS)

    Drake, Jeremy

    2000-01-01

    EUVE, SW, MW and LW spectra have been reduced and line fluxes measured. The Deep Survey data has been analyzed and light curves have been derived. The spectra around the HE II 304 region show some evidence of emission from the bright A companion star, Castor. Preliminary results for the metallicity of the corona of YY Gem were derived from the EUVE spectra and photometry and were presented at the AAS HEAD meeting; results are being finalized for publication in a referred journal.

  5. Martian occultation of epsilon Gem as observed from the C. E. Kenneth Mees Observatory

    NASA Technical Reports Server (NTRS)

    French, R. G.; Goguen, J. D.; Duthie, J. G.

    1978-01-01

    Ground-based observations of the occultation of epsilon Gem by Mars on April 8, 1976 have been reduced to yield the scale height and temperature profiles of the Martian atmosphere for number densities between 10 to the 13th and 10 to the 15th per cu cm. The deduced variations in temperature are remarkably similar to the in situ measurements from the Viking landers.

  6. Performance of the full size nGEM detector for the SPIDER experiment

    NASA Astrophysics Data System (ADS)

    Muraro, A.; Croci, G.; Albani, G.; Claps, G.; Cavenago, M.; Cazzaniga, C.; Dalla Palma, M.; Grosso, G.; Murtas, F.; Pasqualotto, R.; Perelli Cippo, E.; Rebai, M.; Tardocchi, M.; Tollin, M.; Gorini, G.

    2016-03-01

    The ITER neutral beam test facility under construction in Padova will host two experimental devices: SPIDER, a 100 kV negative H/D RF beam source, and MITICA, a full scale, 1 MeV deuterium beam injector. SPIDER will start operations in 2016 while MITICA is expected to start during 2019. Both devices feature a beam dump used to stop the produced deuteron beam. Detection of fusion neutrons produced between beam-deuterons and dump-implanted deuterons will be used as a means to resolve the horizontal beam intensity profile. The neutron detection system will be placed right behind the beam dump, as close to the neutron emitting surface as possible thus providing the map of the neutron emission on the beam dump surface. The system uses nGEM neutron detectors. These are Gas Electron Multiplier detectors equipped with a cathode that also serves as neutron-proton converter foil. The cathode is designed to ensure that most of the detected neutrons at a point of the nGEM surface are emitted from the corresponding beamlet footprint (with dimensions of about 40×22 mm2) on the dump front surface. The size of the nGEM detector for SPIDER is 352 mm×200 mm. Several smaller size prototypes have been successfully made in the last years and the experience gained on these detectors has led to the production of the full size detector for SPIDER during 2014. This nGEM has a read-out board made of 256 pads (arranged in a 16×16 matrix) each with a dimension of 22 mm×13 mm. This paper describes the production of this detector and its tests (in terms of beam profile reconstruction capability, uniformity over the active area, gamma rejection capability and time stability) performed on the ROTAX beam-line at the ISIS spallation source (Didcot-UK).

  7. 100+ years of instrumental seismology: the example of the ISC-GEM Global Earthquake Instrumental Catalogue

    NASA Astrophysics Data System (ADS)

    Storchak, Dmitry; Di Giacomo, Domenico

    2015-04-01

    Systematic seismological observations of earthquakes using seismic instruments on a global scale began more than 100 years ago. Since then seismologists made many discoveries about the Earth interior and the physics of the earthquakes, also thanks to major developments in the seismic instrumentation deployed around the world. Besides, since the establishment of the first global networks (Milne and Jesuit networks), seismologists around the world stored and exchanged the results of routine observations (e.g., picking of arrival times, amplitude-period measurements, etc.) or more sophisticated analyses (e.g., moment tensor inversion) in seismological bulletins/catalogues. With a project funded by the GEM Foundation (www.globalquakemodel.org), the ISC and the Team of International Experts released a new global earthquake catalogue, the ISC-GEM Global Instrumental Earthquake Catalogue (1900 2009) (www.isc.ac.uk/iscgem/index.php), which, differently from previous global seismic catalogues, has the unique feature of covering the entire period of instrumental seismology with locations and magnitude re-assessed using modern approaches for the global earthquakes selected for processing (in the current version approximately 21,000). During the 110 years covered by the ISC-GEM catalogue many seismological developments occurred in terms of instrumentation, seismological practice and knowledge of the physics of the earthquakes. In this contribution we give a brief overview of the major milestones characterizing the last 100+ years of instrumental seismology that were relevant for the production of the ISC-GEM catalogue and the major challenges we faced to obtain a catalogue as homogenous as possible.

  8. Fast data transmission from serial data acquisition for the GEM detector system

    NASA Astrophysics Data System (ADS)

    Kolasinski, Piotr; Pozniak, Krzysztof T.; Czarski, Tomasz; Byszuk, Adrian; Chernyshova, Maryna; Kasprowicz, Grzegorz; Krawczyk, Rafal D.; Wojenski, Andrzej; Zabolotny, Wojciech

    2015-09-01

    This article proposes new method of storing data and transferring it to PC in the X-ray GEM detector system. The whole process is performed by FPGA chips (Spartan-6 series from Xilinx). Comparing to previous methods, new approach allows to store much more data in the system. New, improved implementation of the communication algorithm significantly increases transfer rate between system and PC. In PC data is merged and processed by MATLAB. The structure of firmware implemented in the FPGAs is described.

  9. A Muon Tomography Station with GEM Detectors for Nuclear Threat Detection

    NASA Astrophysics Data System (ADS)

    Staib, Michael; Gnanvo, Kondo; Grasso, Leonard; Hohlmann, Marcus; Locke, Judson; Costa, Filippo; Martoiu, Sorin; Muller, Hans

    2011-10-01

    Muon tomography for homeland security aims at detecting well-shielded nuclear contraband in cargo and imaging it in 3D. The technique exploits multiple scattering of atmospheric cosmic ray muons, which is stronger in dense, high-Z nuclear materials, e.g. enriched uranium, than in low-Z and medium-Z shielding materials. We have constructed and operated a compact Muon Tomography Station (MTS) that tracks muons with six to ten 30 cm x 30 cm Triple Gas Electron Multiplier (GEM) detectors placed on the sides of a 27-liter cubic imaging volume. The 2D strip readouts of the GEMs achieve a spatial resolution of ˜130 μm in both dimensions and the station is operated at a muon trigger rate of ˜20 Hz. The 1,536 strips per GEM detector are read out with the first medium-size implementation of the Scalable Readout System (SRS) developed specifically for Micro-Pattern Gas Detectors by the RD51 collaboration at CERN. We discuss the performance of this MTS prototype and present experimental results on tomographic imaging of high-Z objects with and without shielding.

  10. Study of space-charge dependence on IBF for GEM and Micromegas detectors

    NASA Astrophysics Data System (ADS)

    Yukawa, Kentaro; Hamagaki, Hideki; Gunji, Taku; Yamaguchi, Yorito; Terasaki, Kohei

    2014-09-01

    The MWPC is widely used in a Time Projection Chamber (TPC). To prevent ions created around amplification region from back drifting into the drift space, gating grid system is widely used in the TPC. However, the data taking rate is limited by the operation of the gating grid and the TPC with gating grid system cannot be suitable for the high rate experiments. Micor-Pattern Gaseous Detectors (MPGD) are the possible solutions to overcome the high rate limitations. GEM and Micromegas can absorb positive ions on its electrode or mesh and can reduce the ion backflow into the drift space. In this study, we aim to evaluate performance of ion back flow suppression of GEM and Micromegas detector as a function of space-charge density. We also did the simulation studies using Garfield + + to assess the reproducibility of the space-charge density dependence of the ion back flow obtained in the measurement. In this talk, we will report the overall performances (space-charge density and field dependences of the ion backflow) of GEM and micromegas detectors studied in the measurements and simulations.

  11. Performance verification of the Gravity and Extreme Magnetism Small explorer (GEMS) x-ray polarimeter

    NASA Astrophysics Data System (ADS)

    Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kaneko, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi; Marlowe, Hannah; Griffiths, Scott; Kaaret, Philip E.; Kenward, David; Khalid, Syed

    2014-07-01

    Polarimetry is a powerful tool for astrophysical observations that has yet to be exploited in the X-ray band. For satellite-borne and sounding rocket experiments, we have developed a photoelectric gas polarimeter to measure X-ray polarization in the 2-10 keV range utilizing a time projection chamber (TPC) and advanced micro-pattern gas electron multiplier (GEM) techniques. We carried out performance verification of a flight equivalent unit (1/4 model) which was planned to be launched on the NASA Gravity and Extreme Magnetism Small Explorer (GEMS) satellite. The test was performed at Brookhaven National Laboratory, National Synchrotron Light Source (NSLS) facility in April 2013. The polarimeter was irradiated with linearly-polarized monochromatic X-rays between 2.3 and 10.0 keV and scanned with a collimated beam at 5 different detector positions. After a systematic investigation of the detector response, a modulation factor >=35% above 4 keV was obtained with the expected polarization angle. At energies below 4 keV where the photoelectron track becomes short, diffusion in the region between the GEM and readout strips leaves an asymmetric photoelectron image. A correction method retrieves an expected modulation angle, and the expected modulation factor, ~20% at 2.7 keV. Folding the measured values of modulation through an instrument model gives sensitivity, parameterized by minimum detectable polarization (MDP), nearly identical to that assumed at the preliminary design review (PDR).

  12. A test of GEM T2 from GEOSAT crossovers using latitude lumped coefficients

    NASA Astrophysics Data System (ADS)

    Klokočník, Jaroslav; Wagner, Carl A.

    1994-06-01

    New Latitude Lumped Coefficients (LLC) of a geopotential model are defined as representing the principal differences of the radial distance to a satellite due to the model at single-orbit crossovers in an Exact Repeat Mission. In contrast with previously defined orbital lumped coefficients, the LLC here are dependent only on the geopotential order (without degree distinction) and the latitude. We examine discrepancies in altimetrically determined sea surface heights at over 30000 crossover positions of GEOSAT during its ERM, 1986 1989, after removal of many variable media and surface effects (Cheney et al., 1991) as well as initial condition orbit error. The mean of these discrepancies along well represented latitude bands in the southern hemisphere are used to determine the LLC errors for Goddard Earth Model T2, which was the reference for the GEOSAT sea surface heights. GEM T2 was derived from satelliteonly tracking data with good representation of the GEOSAT orbit. Relating the ”measured” LLC discrepancies to projections of commission error from the GEM T2 variance-covariance matrix, we find that — except for order 3 — GEM T2's performance is as expected. This test represents the first spectral calibration of a gravity model with independent, purely radial orbit data.

  13. Ultraviolet Spectroscopy of PQ Gem and V405 Aur from the HST and IUE Satellites

    NASA Astrophysics Data System (ADS)

    Sanad, M. R.

    2015-10-01

    Ultraviolet spectra of two intermediate polars (IPs), PQ Gem and V405 Aur, observed with Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph and Faint Object Spectrograph and International Ultraviolet Explorer (IUE) satellites were analyzed during the period between 1994-2000. We estimated the reddening of the two systems from the 2200 Å feature. Six spectra of the two systems revealing modulations of line fluxes at different times are presented. PQ Gem and V405 Aur are featured by spectral lines in different ionization states. This paper focuses on the third ionized carbon emission line at 1550 Å and the first ionized helium emission line at 1640 Å produced in the optically thin outer region of the accretion curtain for the two systems by calculating spectral line fluxes. From HST and IUE data, we deduced ultraviolet luminosities and ultraviolet accretion rates for the two binary stars. The average temperature of the accretion streams for PQ Gem and V405 Aur are ˜4500 K and 4100 K, respectively. The results reveal that there are modulations in fluxes of spectral lines, ultraviolet luminosities, and ultraviolet accretion rates with time for both systems. These modulations are referred to the changes of both density and temperature as a result of the variations of mass transfer rate from the secondary star to the primary star. The current results are consistent with an accretion curtain model for IPs.

  14. Discharge probability measurement of a Triple GEM detector irradiated with neutrons

    NASA Astrophysics Data System (ADS)

    Croci, G.; Alfonsi, M.; Ropelewski, L.; Tsipolitis, G.; Fanourakis, G.; Ntomari, E.; Karakostas, K.

    2013-06-01

    Neutron GEM-based detectors represent a new frontier of diagnostic devices in neutron-linked physics applications such as detectors for fusion experiments (Croci et al., 2012 [1]) and spallation sources (Murtas et al., 2012 [2]). Besides, detectors installed in HEP experiments (like LHC at CERN) are dip in a high flux neutron field. For example, the TOTEM T2 GEM telescope (Bagliesi et al., 2010 [3]) at LHC is currently installed very close to the beam pipe where a high intensity (>104 n cm-2 s-1) neutron background is present. In order to assess the capability (particularly related to discharge probability) of working in intense neutrons environment, a 10×10 cm2 Triple GEM detector has been tested using a high flux (105 n cm-2 s-1) neutron beam. The neutron-induced discharge probability PDisch was measured to be 1.37×10-7 at an effective gain G=5×104. In addition, the different types of neutron interactions within the detector were fully explained through a GEANT4 simulation.

  15. The HadGEM2-ES implementation of CMIP5 centennial simulations

    SciTech Connect

    Jones, C. D.; Hughes, JK; Bellouin, N; Hardimann, SC; Jones, GS; Knight, J; Liddicoat, S; O'Connor, FM; Andres, Robert Joseph; Bell, C; Boo, K-O; Bozzo, A; Butchart, N; Cadule, P; Corbin, KD; Doutriaux-Boucher, M; Friedlingstein, P; Gornall, J; Gray, L; Halloran, PR; Hurtt, G; Ingram, WJ; Lamarque, J-F; Law, RM; Meinshausen, M; Osprey, S; Palin, E J; Parsons Chini, L; Raddatz, T; Sanderson, M G; Sellar, A A; Schurer, A; Valdes, P; Wood, N; Woodward, S; Yoshioka, M; Zerroukat, M

    2011-01-01

    The scientific understanding of the Earth s climate system, including the central question of how the climate system is likely to respond to human-induced perturbations, is comprehensively captured in GCMs and Earth System Models (ESM). Diagnosing the simulated climate response, and comparing responses across different models, is crucially dependent on transparent assumptions of how the GCM/ESM has been driven especially because the implementation can involve subjective decisions and may differ between modelling groups performing the same experiment. This paper outlines the climate forcings and setup of the Met Office Hadley Centre ESM, HadGEM2-ES for the CMIP5 set of centennial experiments. We document the prescribed greenhouse gas concentrations, aerosol precursors, stratospheric and tropospheric ozone assumptions, as well as implementation of land-use change and natural forcings for the HadGEM2-ES historical and future experiments following the Representative Concentration Pathways. In addition, we provide details of how HadGEM2-ES ensemble members were initialised from the control run and how the palaeoclimate and AMIP experiments, as well as the emissiondriven RCP experiments were performed.

  16. A simulation study on angular and micro pattern effects in GEM detectors.

    PubMed

    Kim, H G; Jamil, M; Rhee, J T; Ahmad, Farzana; Jeon, Y J

    2016-04-01

    A useful approach for the enhancement of thermal neutrons detection has been reported here. This technique, based on the angular and micro pattern effects, has been developed and applied to the boron-coated ((10)B) Gas Electron multiplier (GEM) detector. In the angular effect case, as a general rule, the detector device is turned at an angle which improves the device response per unit area of the detector. While for the latter case, a regular pattern in the form of micrometer deep grooves is fabricated onto the converter coating, consequently it enhances the capture probability of the detector. For the current study, both of these techniques using a (10)B-coated GEM detector have been simulated for low energy neutrons. For the evaluation of detector response thermal neutrons in the energy ranges from 25meV to 100meV were transported onto the detector surface. For this work, FLUKA MC code has been utilized. The output in both cases has been estimated as a function of incident thermal neutron energies. By employing both techniques, the angle and the micro pattern dependent efficiencies for (10)B-coated GEM detectors are presented, which indicate an improved efficiency response of the device. We anticipate that by using these modifications can lead a further forward step in the development and improvement of thermal neutron detection technology. PMID:26773818

  17. First evidence of hydrous silicic fluid films around solid inclusions in gem-quality diamonds

    NASA Astrophysics Data System (ADS)

    Nimis, Paolo; Alvaro, Matteo; Nestola, Fabrizio; Angel, Ross J.; Marquardt, Katharina; Rustioni, Greta; Harris, Jeff W.; Marone, Federica

    2016-09-01

    Diamonds form from fluids or melts circulating at depth in the Earth's mantle. Analysis of these fluids is possible if they remain entrapped in the diamond during its growth, but this is rarely observed in gem-quality stones. We provide the first evidence that typical mineral inclusions in gem-quality diamonds from the Siberian and Kaapvaal cratons are surrounded by a thin film of hydrous silicic fluid of maximum thickness 1.5 μm. The fluid contains Si2O(OH)6, Si(OH)4, and molecular H2O and was identified using confocal micro-Raman spectroscopy and synchrotron-based X-ray tomographic microscopy. As the solid mineral inclusions have both peridotitic and eclogitic affinities and occur in two cratonic regions, our results demonstrate the strong connection between water-rich fluids and the growth of gem-quality lithospheric diamonds. The presence of the fluid films should be taken into account for a proper evaluation of H2O contents in the mantle based on H2O contents in solid inclusions and for a robust assessment of diamond formation pressures based on the residual pressures of the inclusions.

  18. Performance Verification of the Gravity and Extreme Magnetism Small Explorer GEMS X-Ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kanako, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi; Kenward, David

    2014-01-01

    olarimetry is a powerful tool for astrophysical observations that has yet to be exploited in the X-ray band. For satellite-borne and sounding rocket experiments, we have developed a photoelectric gas polarimeter to measure X-ray polarization in the 2-10 keV range utilizing a time projection chamber (TPC) and advanced micro-pattern gas electron multiplier (GEM) techniques. We carried out performance verification of a flight equivalent unit (1/4 model) which was planned to be launched on the NASA Gravity and Extreme Magnetism Small Explorer (GEMS) satellite. The test was performed at Brookhaven National Laboratory, National Synchrotron Light Source (NSLS) facility in April 2013. The polarimeter was irradiated with linearly-polarized monochromatic X-rays between 2.3 and 10.0 keV and scanned with a collimated beam at 5 different detector positions. After a systematic investigation of the detector response, a modulation factor greater than or equal to 35% above 4 keV was obtained with the expected polarization angle. At energies below 4 keV where the photoelectron track becomes short, diffusion in the region between the GEM and readout strips leaves an asymmetric photoelectron image. A correction method retrieves an expected modulation angle, and the expected modulation factor, approximately 20% at 2.7 keV. Folding the measured values of modulation through an instrument model gives sensitivity, parameterized by minimum detectable polarization (MDP), nearly identical to that assumed at the preliminary design review (PDR).

  19. Effekt einer ad libitum verzehrten fettreduzierten Kost, reich an Obst, Gemüse und Milchprodukten auf den Blutdruck bei Borderline-Hypertonikern

    NASA Astrophysics Data System (ADS)

    Möseneder, Jutta M.

    2002-01-01

    In der randomisierten, multizentrischen DASH-Studie (Dietary Approaches to Stop Hy-pertension), die unter kontrollierten Bedingungen stattfand, führte eine fettreduzierte Mischkost, reich an Obst, Gemüse und Milchprodukten, bei Borderline-Hypertonikern zu einer signifikanten Blutdrucksenkung. Während der Studienphase wurden Körpermasse, Natrium-Aufnahme sowie Alkoholzufuhr aufgrund der bekannten Einflussnahme auf den Blutdruck konstant gehalten. In der eigenen Pilot-Studie sollte untersucht werden, ob das Ergebnis der DASH-Studie (i) mit deutschen Hypertonikern und (ii) unter habituellen Ernährungs- und Lebensbedingungen mit regelmäßig durchgeführter Ernährungsberatung und ad libitum Verzehr anstelle des streng kontrollierten Studienansatzes bestätigt werden kann. Eine Konstanz der Körpermasse, der Natrium-Urinausscheidung (unter diesem Studienansatz valider als die Aufnahme) und des Alkoholkonsums wurde vorausgesetzt. Die Studienpopulation setzte sich aus 53 übergewichtigen Probanden mit einer nicht medikamentös therapierten Borderline-Hypertonie und ohne Stoffwechselerkrankungen zusammen. Die Studienteilnehmer wurden randomisiert entweder der Idealgruppe mit einer fettarmen Kost reich an Milchprodukten, Obst und Gemüse (ähnlich der DASH-Idealgruppe) oder der Kontrollgruppe mit habitueller Ernährungsweise zugeteilt. Über einen Zeitraum von fünf Wochen wurde den Probanden etwa 50% ihres täglichen Lebensmittelbedarfes entsprechend ihrer Gruppenzugehörigkeit kostenfrei zur Verfügung gestellt. Gelegenheitsblutdruckmessungen und 24h-Blutdruckmessungen, Ernährungs- und Aktivitätsprotokolle, Blut- und Urinproben sowie anthropometrische Messungen wurden vor, während und fünf Wochen nach der Interventionsphase durchgeführt. Die Ergebnisse zeigen, dass in der Idealgruppe keine signifikante Blutdrucksenkung beobachtet werden konnte. Dies lässt sich durch die Tatsache erklären, dass die Lebens-mittel- und Nährstoffaufnahme der deutschen

  20. Effekt einer ad libitum verzehrten fettreduzierten Kost, reich an Obst, Gemüse und Milchprodukten auf den Blutdruck bei Borderline-Hypertonikern

    NASA Astrophysics Data System (ADS)

    Möseneder, Jutta M.

    2002-01-01

    In der randomisierten, multizentrischen DASH-Studie (Dietary Approaches to Stop Hy-pertension), die unter kontrollierten Bedingungen stattfand, führte eine fettreduzierte Mischkost, reich an Obst, Gemüse und Milchprodukten, bei Borderline-Hypertonikern zu einer signifikanten Blutdrucksenkung. Während der Studienphase wurden Körpermasse, Natrium-Aufnahme sowie Alkoholzufuhr aufgrund der bekannten Einflussnahme auf den Blutdruck konstant gehalten. In der eigenen Pilot-Studie sollte untersucht werden, ob das Ergebnis der DASH-Studie (i) mit deutschen Hypertonikern und (ii) unter habituellen Ernährungs- und Lebensbedingungen mit regelmäßig durchgeführter Ernährungsberatung und ad libitum Verzehr anstelle des streng kontrollierten Studienansatzes bestätigt werden kann. Eine Konstanz der Körpermasse, der Natrium-Urinausscheidung (unter diesem Studienansatz valider als die Aufnahme) und des Alkoholkonsums wurde vorausgesetzt. Die Studienpopulation setzte sich aus 53 übergewichtigen Probanden mit einer nicht medikamentös therapierten Borderline-Hypertonie und ohne Stoffwechselerkrankungen zusammen. Die Studienteilnehmer wurden randomisiert entweder der Idealgruppe mit einer fettarmen Kost reich an Milchprodukten, Obst und Gemüse (ähnlich der DASH-Idealgruppe) oder der Kontrollgruppe mit habitueller Ernährungsweise zugeteilt. Über einen Zeitraum von fünf Wochen wurde den Probanden etwa 50% ihres täglichen Lebensmittelbedarfes entsprechend ihrer Gruppenzugehörigkeit kostenfrei zur Verfügung gestellt. Gelegenheitsblutdruckmessungen und 24h-Blutdruckmessungen, Ernährungs- und Aktivitätsprotokolle, Blut- und Urinproben sowie anthropometrische Messungen wurden vor, während und fünf Wochen nach der Interventionsphase durchgeführt. Die Ergebnisse zeigen, dass in der Idealgruppe keine signifikante Blutdrucksenkung beobachtet werden konnte. Dies lässt sich durch die Tatsache erklären, dass die Lebens-mittel- und Nährstoffaufnahme der deutschen

  1. Application of complex trace analysis for improved target identification in gem-tourmaline-bearing pegmatites in the Himalaya mine, San Diego County, California

    NASA Astrophysics Data System (ADS)

    Patterson, Jeffrey E.; Cook, Frederick A.

    2000-04-01

    Gem bearing miarolitic cavities in rare metal, lithium enriched, granitic pegmatites pose challenging exploration targets, as they are not readily identifiable using normal geophysical methods. Application of ground penetrating radar (GPR) has been successful in delineating gem-bearing zones in the Himalaya pegmatite mine in San Diego County, California. Careful setup and data processing, using complex signal analysis, have so far allowed us to distinguish between gem- bearing pockets, non-gem bearing pockets, and barren/frozen dike. Each of us independently hypothesized, in 1995, that GPR could be an appropriate tool for gemstone exploration in the subsurface exposures in adits, drifts and stopes of many gem mines (Patterson, 1996; Cook, 1997). The culmination of these efforts was reached in June, 1998, with the first documented discovery of gem tourmaline pockets using this technique.

  2. GEM-TREND: a web tool for gene expression data mining toward relevant network discovery

    PubMed Central

    Feng, Chunlai; Araki, Michihiro; Kunimoto, Ryo; Tamon, Akiko; Makiguchi, Hiroki; Niijima, Satoshi; Tsujimoto, Gozoh; Okuno, Yasushi

    2009-01-01

    Background DNA microarray technology provides us with a first step toward the goal of uncovering gene functions on a genomic scale. In recent years, vast amounts of gene expression data have been collected, much of which are available in public databases, such as the Gene Expression Omnibus (GEO). To date, most researchers have been manually retrieving data from databases through web browsers using accession numbers (IDs) or keywords, but gene-expression patterns are not considered when retrieving such data. The Connectivity Map was recently introduced to compare gene expression data by introducing gene-expression signatures (represented by a set of genes with up- or down-regulated labels according to their biological states) and is available as a web tool for detecting similar gene-expression signatures from a limited data set (approximately 7,000 expression profiles representing 1,309 compounds). In order to support researchers to utilize the public gene expression data more effectively, we developed a web tool for finding similar gene expression data and generating its co-expression networks from a publicly available database. Results GEM-TREND, a web tool for searching gene expression data, allows users to search data from GEO using gene-expression signatures or gene expression ratio data as a query and retrieve gene expression data by comparing gene-expression pattern between the query and GEO gene expression data. The comparison methods are based on the nonparametric, rank-based pattern matching approach of Lamb et al. (Science 2006) with the additional calculation of statistical significance. The web tool was tested using gene expression ratio data randomly extracted from the GEO and with in-house microarray data, respectively. The results validated the ability of GEM-TREND to retrieve gene expression entries biologically related to a query from GEO. For further analysis, a network visualization interface is also provided, whereby genes and gene annotations

  3. Education Outreach at MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Censabella, V.; Rivenberg, P.

    1999-11-01

    Outreach at the MIT PSFC consists of volunteers working together to increase the public's knowledge of fusion and plasma-related experiments. Seeking to generate excitement about science, engineering and mathematics, the PSFC holds a number of outreach activities throughout the year, such as Middle and High School Outreach Days. Outreach also includes the Mr. Magnet Program, which uses an interactive strategy to engage elementary school children. The PSFC maintains a Home Page on the World Widee Web, which can be reached at http://psfc.mit.edu.

  4. The US DOE/MIT Innovation Acceleration Competition

    SciTech Connect

    None, None

    2009-06-30

    The Competition asked student teams from several US Universities to propose business models, technological systems, and policy framework to accelerate the penetration of new vehicle and fuel technologies into the markets. In May 2009 the final selection of teams was announced and four of five finalist teams flew to Washington DC to present to the US Department of Energy. The five finalist teams were 1. Filter Sensing Technologies (FST) (MIT), 2. Flex Cathode Technology for Electric Vehicle Batteries, 3. Green Guidance (RPI), 4. Levant Power (MIT), and 5. Wind-Driven Paddlewheel Cylinder for Energy Storage in Freighter Trucks (Villanova). The five finalists entries are described.

  5. Modelling two-way interactions between atmospheric pollution and weather using high-resolution GEM-MACH

    NASA Astrophysics Data System (ADS)

    Makar, Paul; Gong, Wanmin; Pabla, Balbir; Cheung, Philip; Milbrandt, Jason; Gravel, Sylvie; Moran, Michael; Gilbert, Samuel; Zhang, Junhua; Zheng, Qiong

    2013-04-01

    The Global Environmental Multiscale (GEM) model is the source of the Canadian government's operational numerical weather forecast guidance, and GEM-MACH is the Canadian operational air-quality forecast model. GEM-MACH comprises GEM and the 'Modelling Air-quality and Chemistry' module, a gas-phase, aqueous-phase and aerosol chemistry and microphysics subroutine package called from within GEM's physics module. The present operational GEM-MACH model is "on-line" (both chemistry and meteorology are part of the same modelling structure) but is not fully coupled (weather variables are provided as inputs to the chemistry, but the chemical variables are not used to modify the weather). In this work, we describe modifications made to GEM-MACH as part of the 2nd phase of the Air Quality Model Evaluation International Initiative, in order to bring the model to a fully coupled status and present the results of initial tests comparing uncoupled and coupled versions of the model to observations for a high-resolution forecasting system. Changes to GEM's cloud microphysics and radiative transfer packages were carried out to allow two-way coupling. The cloud microphysics package used here is the Milbrandt-Yau 2-moment (MY2) bulk microphysics scheme, which solves prognostic equations for the total droplet number concentration and the mass mixing ratios of six hydrometeor categories. Here, we have replaced the original cloud condensation nucleation parameterization of MY2 (empirically relating supersaturation and CCN number) with the aerosol activation scheme of Abdul-Razzak and Ghan (2002). The latter scheme makes use of the particle size and speciation distribution of GEM-MACH's chemistry code as well as meteorological inputs to predict the number of aerosol particles activated to form cloud droplets, which is then used in the MY2 microphysics. The radiative transfer routines of GEM assume a default constant concentration aerosol profile between the surface and 1500m, and a single

  6. MIT Research Program on Communications Policy; First Annual Report.

    ERIC Educational Resources Information Center

    Massachusetts Inst. of Tech., Cambridge. Research Program on Communications Policy.

    The first year's activities of the Massachusetts Institute of Technology (MIT) Research Program on Communication Policy are described. Among the projects undertaken were studies of: (1) land mobile radio systems, (2) direct satellite broadcasting in foreign countries, (3) communications regulation policy, (4) international data communication, and…

  7. MIT Orients Course Materials Online to K-12

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2008-01-01

    Many science and mathematics educators across the country are taking advantage of a Web site created by the Massachusetts Institute of Technology (MIT), the famed research university located in Cambridge, Massachusetts, which offers free video, audio, and print lectures and course material taken straight from the school's classes. Those resources…

  8. MIT Mints a Valuable New Form of Academic Currency

    ERIC Educational Resources Information Center

    Carey, Kevin

    2012-01-01

    The Massachusetts Institute of Technology (MIT) has invented or improved many world-changing things--radar, information theory, and synthetic self-replicating molecules, to name a few. Last month the university announced, to mild fanfare, an invention that could be similarly transformative, this time for higher education itself. It is called MITx.…

  9. The Creation of OpenCourseWare at MIT

    ERIC Educational Resources Information Center

    Abelson, Hal

    2008-01-01

    This paper traces the genesis of the MIT OpenCourseWare project from its initial strategic precursors in 1999 and 2000, through its launch in 2001 and its subsequent evolution. The story told here illuminates the interplay among institutional leadership, and strategic planning, and with university culture in launching major educational technology…

  10. STRONG VARIABLE ULTRAVIOLET EMISSION FROM Y GEM: ACCRETION ACTIVITY IN AN ASYMPTOTIC GIANT BRANCH STAR WITH A BINARY COMPANION?

    SciTech Connect

    Sahai, Raghvendra; Neill, James D.; Gil de Paz, Armando; Sanchez Contreras, Carmen

    2011-10-20

    Binarity is believed to dramatically affect the history and geometry of mass loss in asymptotic giant branch (AGB) and post-AGB stars, but observational evidence of binarity is sorely lacking. As part of a project to look for hot binary companions to cool AGB stars using the Galaxy Evolution Explorer archive, we have discovered a late-M star, Y Gem, to be a source of strong and variable UV emission. Y Gem is a prime example of the success of our technique of UV imaging of AGB stars in order to search for binary companions. Y Gem's large and variable UV flux makes it one of the most prominent examples of a late-AGB star with a mass accreting binary companion. The UV emission is most likely due to emission associated with accretion activity and a disk around a main-sequence companion star. The physical mechanism generating the UV emission is extremely energetic, with an integrated luminosity of a few x L{sub sun} at its peak. We also find weak CO J = 2-1 emission from Y Gem with a very narrow line profile (FWHM of 3.4 km s{sup -1}). Such a narrow line is unlikely to arise in an outflow and is consistent with emission from an orbiting, molecular reservoir of radius 300 AU. Y Gem may be the progenitor of the class of post-AGB stars which are binaries and possess disks but no outflows.

  11. Evaluation of Tropical Convection Regimes in the HadGEM2 Model Using Radio Occultation Observations

    NASA Astrophysics Data System (ADS)

    Lackner, B. C.; Steiner, A. K.; Ringer, M. A.; Kirchengast, G.

    2011-12-01

    The evaluation of Global Climate Models (GCMs) requires high-quality observational data sets. Global Positioning System (GPS) Radio Occultation (RO) measurements, which are available continuously from various satellite missions since 2001, provide a global and independent data record for the upper troposphere and lower stratosphere (UTLS). The measurements are based on precise atomic clocks and feature long-term stability, homogeneity, and accuracy. Best data quality is achieved at about 5 km to 30 km altitude and observational errors are well characterized. Profiles of key climate variables, such as refractivity, pressure, geopotential height, and temperature, are retrieved at a high vertical resolution of about 0.5 km in the troposphere to 1.5 km in the stratosphere. Due to these characteristics, RO qualifies as climate benchmark data type, which can be used for the evaluation of climate models. In this presentation we focus on physical processes relevant to tropical water vapor/lapse rate feedback. Water vapor and lapse rate responses are closely coupled in the upper troposphere and models with larger negative lapse rate feedback also have a larger positive water vapor feedback. We show first results on the representation of UTLS temperature lapse rates and refractivity gradients in RO observations and in Met Office Hadley Centre HadGEM2 model data. To allow a consistent and process-oriented approach, we classify moist and dry tropical regimes through distinction between dynamical up- and downdraft regions. The pressure vertical velocity at 500 hPa (ω500) and surface temperature (T) from ERA-Interim (for RO profiles) and from the HadGEM2 model itself (for the model) is used for the classification of these regimes. RO data and co-located HadGEM2 model profiles are sorted and sampled into vertical velocity classes and a systematic comparison is performed. A better insight into observation and model behavior in tropical convection regimes will contribute to the

  12. On the challenges of high resolution forecasting with the Global Environmental Multiscale (GEM) atmospheric model

    NASA Astrophysics Data System (ADS)

    Zahid Husain, Syed; Girard, Claude

    2016-04-01

    High resolution forecasting at the sub-kilometer scale with the Global Environmental Multiscale (GEM) atmospheric model leads to a number of challenges. The three-dimensional elliptic problem resulting from vertical discretization imposes severe restrictions on the vertical resolution and the time-step size in order to maintain vertical separability that permits the use of a direct solver. Although iterative solvers do not depend on vertical separability, readjusting the contributions of the nonhydrostatic pressure perturbation is found to circumvent the separability issue for the direct solver. In addition to the vertical-separability problem, at sub-kilometer resolutions the model currently exhibits strong instability particularly over complex orography where the model may encounter mountains with steep slopes. Off-centered averaging in the semi-Lagrangian scheme as well as the explicit high order numerical diffusion scheme - available within the GEM model to control high wave number noise - are found to be inadequate in addressing this strong orography-induced instability. Increasing the level of off-centering for the equations attributable to the non-hydrostatic aspects of the atmospheric flow is found to improve model stability during preliminary tests. Furthermore, as the existing hyperdiffusion schemes in GEM does not conserve angular momentum a new Smagorinsky-type diffusion scheme is currently being developed that will be compatible with the conservation laws. The improved diffusion scheme coupled with the modified off-centering of the non-hydrostatic equations is expected to have a more meaningful impact on the orgography-induced instability. Pertinent results will be presented at the conference.

  13. 2D dosimetry in a proton beam with a scintillating GEM detector

    NASA Astrophysics Data System (ADS)

    Seravalli, E.; de Boer, M. R.; Geurink, F.; Huizenga, J.; Kreuger, R.; Schippers, J. M.; van Eijk, C. W. E.

    2009-06-01

    A two-dimensional position-sensitive dosimetry system based on a scintillating gas detector is being developed for pre-treatment verification of dose distributions in particle therapy. The dosimetry system consists of a chamber filled with an Ar/CF4 scintillating gas mixture, inside which two gas electron multiplier (GEM) structures are mounted (Seravalli et al 2008b Med. Phys. Biol. 53 4651-65). Photons emitted by the excited Ar/CF4 gas molecules during the gas multiplication in the GEM holes are detected by a mirror-lens-CCD camera system. The intensity distribution of the measured light spot is proportional to the 2D dose distribution. In this work, we report on the characterization of the scintillating GEM detector in terms of those properties that are of particular importance in relative dose measurements, e.g. response reproducibility, dose dependence, dose rate dependence, spatial and time response, field size dependence, response uniformity. The experiments were performed in a 150 MeV proton beam. We found that the detector response is very stable for measurements performed in succession (σ = 0.6%) and its response reproducibility over 2 days is about 5%. The detector response was found to be linear with the dose in the range 0.05-19 Gy. No dose rate effects were observed between 1 and 16 Gy min-1 at the shallow depth of a water phantom and 2 and 38 Gy min-1 at the Bragg peak depth. No field size effects were observed in the range 120-3850 mm2. A signal rise and fall time of 2 µs was recorded and a spatial response of <=1 mm was measured.

  14. Multiplexed barcoded CRISPR-Cas9 screening enabled by CombiGEM.

    PubMed

    Wong, Alan S L; Choi, Gigi C G; Cui, Cheryl H; Pregernig, Gabriela; Milani, Pamela; Adam, Miriam; Perli, Samuel D; Kazer, Samuel W; Gaillard, Aleth; Hermann, Mario; Shalek, Alex K; Fraenkel, Ernest; Lu, Timothy K

    2016-03-01

    The orchestrated action of genes controls complex biological phenotypes, yet the systematic discovery of gene and drug combinations that modulate these phenotypes in human cells is labor intensive and challenging to scale. Here, we created a platform for the massively parallel screening of barcoded combinatorial gene perturbations in human cells and translated these hits into effective drug combinations. This technology leverages the simplicity of the CRISPR-Cas9 system for multiplexed targeting of specific genomic loci and the versatility of combinatorial genetics en masse (CombiGEM) to rapidly assemble barcoded combinatorial genetic libraries that can be tracked with high-throughput sequencing. We applied CombiGEM-CRISPR to create a library of 23,409 barcoded dual guide-RNA (gRNA) combinations and then perform a high-throughput pooled screen to identify gene pairs that inhibited ovarian cancer cell growth when they were targeted. We validated the growth-inhibiting effects of specific gene sets, including epigenetic regulators KDM4C/BRD4 and KDM6B/BRD4, via individual assays with CRISPR-Cas-based knockouts and RNA-interference-based knockdowns. We also tested small-molecule drug pairs directed against our pairwise hits and showed that they exerted synergistic antiproliferative effects against ovarian cancer cells. We envision that the CombiGEM-CRISPR platform will be applicable to a broad range of biological settings and will accelerate the systematic identification of genetic combinations and their translation into novel drug combinations that modulate complex human disease phenotypes. PMID:26864203

  15. First Year K-12 Teachers as High Leverage Point to Implement GEMS Space Science Curriculum Sequence

    NASA Astrophysics Data System (ADS)

    Slater, Timothy F.; Mendez, B. J.; Schultz, G.; Wierman, T.

    2013-01-01

    The recurring challenge for curriculum developers is how to efficiently prepare K-12 classroom teachers to use new curricula. First-year teachers, numbering nearly 250,000 in the US each year, have the greatest potential to impact the largest number of students because they have potential to be in the classroom for thirty years. At the same time, these novice teachers are often the most open minded about adopting curricular innovation because they are not yet deeply entrenched in existing practices. To take advantage of this high leverage point, a collaborative of space scientists and science educators at the University of California, Berkeley’s Lawrence Hall of Science and Center for Science Education at the Space Sciences Laboratory with experts from the Astronomical Society of the Pacific, the University of Wyoming, and the CAPER Center for Astronomy & Physics Education experimented with a unique professional development model focused on helping master teachers work closely with pre-service teachers during their student teaching internship field experience. The Advancing Mentor and Novice Teachers in Space Science (AMANTISS) team first identified master teachers who supervise novice, student teachers and trained these master teachers to use the GEMS Space Science Curriculum Sequence. Then, these master teachers were mentored in coaching interning student teachers assigned to them in using GEMS materials. Evaluation showed that novice teachers mentored by the master teachers felt knowledgeable after teaching the GEMS units. However, they seemed relatively less confident about the solar system and objects beyond the solar system. Overall, mentees felt strongly at the end of the year that they have acquired good strategies for teaching the various topics, suggesting that the support they received while teaching and working with a mentor was of real benefit to them. Funding provided in part by NASA ROSES AMANTISS NNX09AD51G

  16. Multiplexed barcoded CRISPR-Cas9 screening enabled by CombiGEM

    PubMed Central

    Wong, Alan S. L.; Choi, Gigi C. G.; Cui, Cheryl H.; Pregernig, Gabriela; Milani, Pamela; Adam, Miriam; Perli, Samuel D.; Kazer, Samuel W.; Gaillard, Aleth; Hermann, Mario; Shalek, Alex K.; Fraenkel, Ernest; Lu, Timothy K.

    2016-01-01

    The orchestrated action of genes controls complex biological phenotypes, yet the systematic discovery of gene and drug combinations that modulate these phenotypes in human cells is labor intensive and challenging to scale. Here, we created a platform for the massively parallel screening of barcoded combinatorial gene perturbations in human cells and translated these hits into effective drug combinations. This technology leverages the simplicity of the CRISPR-Cas9 system for multiplexed targeting of specific genomic loci and the versatility of combinatorial genetics en masse (CombiGEM) to rapidly assemble barcoded combinatorial genetic libraries that can be tracked with high-throughput sequencing. We applied CombiGEM-CRISPR to create a library of 23,409 barcoded dual guide-RNA (gRNA) combinations and then perform a high-throughput pooled screen to identify gene pairs that inhibited ovarian cancer cell growth when they were targeted. We validated the growth-inhibiting effects of specific gene sets, including epigenetic regulators KDM4C/BRD4 and KDM6B/BRD4, via individual assays with CRISPR-Cas–based knockouts and RNA-interference–based knockdowns. We also tested small-molecule drug pairs directed against our pairwise hits and showed that they exerted synergistic antiproliferative effects against ovarian cancer cells. We envision that the CombiGEM-CRISPR platform will be applicable to a broad range of biological settings and will accelerate the systematic identification of genetic combinations and their translation into novel drug combinations that modulate complex human disease phenotypes. PMID:26864203

  17. GEMMA and GEMINI, two dedicated mixed-signal ASICs for Triple-GEM detectors readout

    NASA Astrophysics Data System (ADS)

    Pezzotta, A.; Croci, G.; Costantini, A.; De Matteis, M.; Tagnani, D.; Corradi, G.; Murtas, F.; Gorini, G.; Baschirotto, A.

    2016-03-01

    GEMMA and GEMINI, two integrated-circuit front-ends for the Triple-GEM detector are presented. These two ASICs aim to improve detector readout performance in terms of count rate, adaptability, portability and power consumption. GEMMA target is to embed counting, timing and spectroscopic measurements in a single 8-channel device, managing a detector capacitance up to 15 pF. On the other hand, GEMINI is dedicated to counting measurements, embedding 16 channels with a detector capacitance up to 40 pF. Both prototypes, fabricated in 130 nm and 180 nm CMOS respectively, feature an automatic on-chip calibration circuit, compensating for process/temperature variations.

  18. Triple-GEM Detectors for the Innermost Region of the LHCb Muon Apparatus

    SciTech Connect

    Poli Lener, M

    2005-10-12

    We present in this paper the mechanical construction procedures, the tools and the relative quality check of a triple-GEM detector. This kind of detector is the result of R and D activity performed for the study of detectors for the hard radiation environment of the innermost region, around the beam pipe, of the first muon station of the LHCb experiment. We also present the performances of the chamber final design, operated with Ar/CO2/CF4 (45/15/40) gas mixture, obtained at PS beam facility at CERN.

  19. Single Electron Detection in Quadruple-GEM Detector with Pad Readout

    SciTech Connect

    Va'vra, Jaroslav

    2001-03-07

    Using a system of four GEMs operating in tandem and coupled to pad readout, we have demonstrated the detection of single electrons in ethane at 1 bar. The paper presents measurements of single electron pulse height distributions, total gas gain measurement and calculation, pad-to-pad cross-talk, quenching capability, high rate capability, charging effects, etc. We describe the overall operational experience, including addition of a gaseous photocathode, TMAE, and compare it to the SLD CRID single-electron detector [1], which has been operational during the past decade.

  20. OH emission in the direction of TV Gem and BI Cyg

    NASA Technical Reports Server (NTRS)

    Brown, L. W.; Hobbs, R. W.; Michalitsianos, A. G.; Kafatos, M.

    1981-01-01

    The NRAO-Green Bank 43-m telescope and 18-cm receiver have detected OH maser main-line emission at 1665 MHz, in the direction of the two late-type supergiants TV Gem and BI Cyg. The detection of the two new OH maser sources is noteworthy in view of the small number of late-type supergiants known to be molecular radio sources, or associated in close proximity with OH emission clouds. The IR, UV and radio properties of the two stars are discussed.

  1. Monolithic front-end ICs for interpolating cathode pad and strip detectors for GEM

    SciTech Connect

    O`Connor, P.

    1993-05-01

    We are developing CMOS circuits for readout of interpolating cathode strip and pad chambers for the GEM experiment at the SSC. Because these detectors require position resolution of about 1% of the strip pitch, the electronic noise level must be less than 2000 electrons. Several test chips have been fabricated to demonstrate the feasibility of achieving the combination of low noise, speed, and wide dynamic range in CMOS. Results to date show satisfactory noise and linearity performance. Future development will concentrate on radiation-hardening the central tracker ASIC design, optimizing the shaper peaking time and noise contribution, providing more user-configurable output options, and packaging and test issues.

  2. Gem-difluoromethylated and trifluoromethylated derivatives of DMDP-related iminosugars: synthesis and glycosidase inhibition.

    PubMed

    Li, Yi-Xian; Kinami, Kyoko; Hirokami, Yuki; Kato, Atsushi; Su, Jia-Kun; Jia, Yue-Mei; Fleet, George W J; Yu, Chu-Yi

    2016-02-21

    Gem-difluoromethylated and trifluoromethylated derivatives of DMDP-related iminosugars have been synthesized from cyclic nitrones 12, 13, 18, ent-18 or 23 and nitrone-derived aldehydes 20 or ent-20. The fluorinated iminosugars were assayed against various glycosidases, and ent-8 showed moderate but selective α-l-rhamnosidase inhibition. Difluoro or trifluoro units influenced the inhibitory activities of iminosugars in a more complex manner than single fluoro substitution. This may be correlated with their highly hydrophobic character and strong electron-withdrawing effect. PMID:26790356

  3. Evidence for a Companion to BM Gem, a Silicate Carbon Star

    NASA Astrophysics Data System (ADS)

    Izumiura, Hideyuki; Noguchi, Kunio; Aoki, Wako; Honda, Satoshi; Ando, Hiroyasu; Takada-Hidai, Masahide; Kambe, Eiji; Kawanomoto, Satoshi; Sadakane, Kozo; Sato, Bun'ei; Tajitsu, Akito; Tanaka, Wataru; Okita, Ki'ichi; Watanabe, Etsuji; Yoshida, Michitoshi

    2008-07-01

    Balmer and Paschen continuum emission, as well as Balmer series lines of P Cygni-type profile from Hγ through H23, are revealed in the violet spectra of BM Gem, a carbon star associated with an oxygen-rich circumstellar shell ("silicate carbon star"). The blueshifted absorption in the Balmer lines indicates the presence of an outflow, the line-of-sight velocity of which is at least 400 km s-1. The Balmer lines show a significant change in profile over a period of 75 days. We argue that the observed unusual features in BM Gem are strong evidence for the presence of a companion, which should form an accretion disk that gives rise to both an ionized gas region and a high-velocity variable outflow. The estimated luminosity of ~0.2 (0.03-0.6) L⊙ for the ionized gas can be maintained by a mass accretion rate for a dwarf companion of ~10-8 M⊙ yr-1, while ~10-10 M⊙ yr-1 is sufficient for accretion to a white dwarf companion. These accretion rates are feasible for some detached binary configurations on the basis of the Bondi-Hoyle-type accretion process. Therefore, we conclude that the carbon star BM Gem is in a detached binary system with a companion of low mass and low luminosity. However, we are unable to determine whether this companion object is a dwarf or a white dwarf, although the gas outflow velocity of 400 km s-1, as well as the nondetection in the X-ray survey, favor its identity as a dwarf star. The upper limits for binary separation are 210 and 930 AU for a dwarf and a white dwarf, respectively, in the case of circular orbit. We also note that the observed features of BM Gem mimic those of Mira (ο Cet), which may suggest actual similarities in their binary configurations and circumstellar structures. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  4. A 40 GByte/s read-out system for GEM

    SciTech Connect

    Bowden, M.; Carrel, J.; Dorenbosch, J.; Kapoor, V.

    1994-04-01

    The preliminary design of the read-out system for the GEM (Gammas, Electrons, Muons) detector at the Superconducting Super Collider is presented. The system reads all digitized data from the detector data sources at a Level 1 trigger rate of up to 100 kHz. A total read-out bandwidth of 40 GBytes/s is available. Data are stored in buffers that are accessible for further event filtering by an on-line, processor farm. Data are transported to the farm only as they are needed by the higher-level trigger algorithms, leading to a reduced bandwidth requirement in the Data Acquisition System.

  5. Operation of gas electron multiplier (GEM) with propane gas at low pressure and comparison with tissue-equivalent gas mixtures

    NASA Astrophysics Data System (ADS)

    De Nardo, L.; Farahmand, M.

    2016-05-01

    A Tissue-Equivalent Proportional Counter (TEPC), based on a single GEM foil of standard geometry, has been tested with pure propane gas at low pressure, in order to simulate a tissue site of about 1 μm equivalent size. In this work, the performance of GEM with propane gas at a pressure of 21 and 28 kPa will be presented. The effective gas gain was measured in various conditions using a 244Cm alpha source. The dependence of effective gain on the electric field strength along the GEM channel and in the drift and induction region was investigated. A maximum effective gain of about 5×103 has been reached. Results obtained in pure propane gas are compared with gas gain measurements in gas mixtures commonly employed in microdosimetry, that is propane and methane based Tissue-Equivalent gas mixtures.

  6. OpenGeoSys-Gem: A numerical tool for calculating geochemical and porosity changes in saturated and partially saturated media

    NASA Astrophysics Data System (ADS)

    Kosakowski, Georg; Watanabe, Norihiro

    Reactive transport codes that use a Gibbs Energy Minimization (GEM) to solve chemical equilibria are uncommon. We present a new coupling of the Richards flow module of the Finite Element (FE) based OpenGeoSys code with the GEM based chemical solver GEMS3K. The coupled code is highly parallelized using an overlapping domain decomposition approach in combination with execution of multiple threads that solve chemical equilibria in parallel. FE reactive transport schemes are often affected by spurious concentration oscillations. We effectively suppress these oscillations with a linearized algebraic flux corrected transport (FCT) algorithm. An application example is presented which investigates the evolution of material interfaces in a deep geological repository for nuclear waste. The example uses all features of the new coupled code: flow and multi-component transport in variably saturated media, and a very complex chemical setup which makes extensive use of (non-linear) solid solution formulations for mineral phases.

  7. Measurement of the spark probability of a GEM detector for the CBM muon chamber (MuCh)

    NASA Astrophysics Data System (ADS)

    Biswas, S.; Abuhoza, A.; Frankenfeld, U.; Garabatos, C.; Hehner, J.; Kleipa, V.; Morhardt, T.; Schmidt, C. J.; Schmidt, H. R.; Wiechula, J.

    2015-11-01

    The triple GEM detectors for the CBM muon chamber (MuCh) will be operated in a high rate environment of heavily ionizing particles due to the presence of thick iron absorber in the system. Therefore, the stability of the detectors needs to be tested. In a dedicated beam time double mask triple GEM detectors have been tested at CERN SPS/H4. In this study pion beam of ~ 150 GeV/c has been used. Different methods to determine the spark has been described in this paper. The stability of the triple GEM detector setup in an environment of high energetic showers is studied. To this end the spark probability in a shower environment is compared to the spark probability in a pion beam. The spark probability was found to be ~10-7 in a high momentum pion beam and in an induced particle shower.

  8. Quality control and beam test of GEM detectors for future upgrades of the CMS muon high rate region at the LHC

    NASA Astrophysics Data System (ADS)

    Abbaneo, D.; Abbas, M.; Abbrescia, M.; Abdelalim, A. A.; Abi Akl, M.; Ahmed, W.; Ahmed, W.; Altieri, P.; Aly, R.; Armaingaud, C.; Asawatangtrakuldee, C.; Ashfaq, A.; Aspell, P.; Assran, Y.; Awan, I.; Bally, S.; Ban, Y.; Banerjee, S.; Barria, P.; Benussi, L.; Bhopatkar, V.; Bianco, S.; Bos, J.; Bouhali, O.; Braibant, S.; Buontempo, S.; Cai, J.; Calabria, C.; Caponero, M.; Caputo, C.; Cassese, F.; Castaneda, A.; Cauwenbergh, S.; Cavallo, F. R.; Celik, A.; Choi, M.; Choi, K.; Choi, S.; Christiansen, J.; Cimmino, A.; Colafranceschi, S.; Colaleo, A.; Conde Garcia, A.; Dabrowski, M. M.; De Lentdecker, G.; De Oliveira, R.; De Robertis, G.; Dildick, S.; Dildick, S.; Dorney, B.; Elmetenawee, W.; Fabrice, G.; Ferrini, M.; Ferry, S.; Flanagan, W.; Giacomelli, P.; Gilmore, J.; Guiducci, L.; Gutierrez, A.; Hadjiiska, R. M.; Hassan, A.; Hauser, J.; Hoepfner, K.; Hohlmann, M.; Hoorani, H.; Jeng, Y. G.; Kamon, T.; Karchin, P. E.; Kim, H. S.; Khotilovich, V.; Krutelyov, S.; Kumar, A.; Lee, J.; Lenzi, T.; Litov, L.; Loddo, F.; Maerschalk, T.; Magazzu, G.; Maggi, M.; Maghrbi, Y.; Magnani, A.; Majumdar, N.; Mal, P. K.; Mandal, K.; Marchioro, A.; Marinov, A.; Merlin, J. A.; Mohammed, N.; Mohanty, A. K.; Mohapatra, A.; Muhammad, S.; Mukhopadhyay, S.; Naimuddin, M.; Nuzzo, S.; Oliveri, E.; Pant, L. M.; Paolucci, P.; Park, I.; Passeggio, G.; Pavlov, B.; Philipps, B.; Phipps, M.; Piccolo, D.; Postema, H.; Pugliese, G.; Baranac, A. Puig; Radi, A.; Radogna, R.; Raffone, G.; Ramkrishna, S.; Ranieri, A.; Riccardi, C.; Rodrigues, A.; Ropelewski, L.; RoyChowdhury, S.; Ryu, M. S.; Ryu, G.; Safonov, A.; Sakharov, A.; Salva, S.; Saviano, G.; Sharma, A.; Swain, S. K.; Talvitie, J. P.; Talvitie, J. P.; Tamma, C.; Tatarinov, A.; Teng, H.; Turini, N.; Tuuva, T.; Twigger, J.; Tytgat, M.; Vai, I.; Van Stenis, M.; Venditi, R.; Verhagen, E.; Verwilligen, P.; Vitulo, P.; Wang, D.; Wang, M.; Yang, U.; Yang, Y.; Yonamine, R.; Zaganidis, N.; Zenoni, F.; Zhang, A.

    2015-03-01

    Gas Electron Multipliers (GEM) are a proven position sensitive gas detector technology which nowadays is becoming more widely used in High Energy Physics. GEMs offer an excellent spatial resolution and a high particle rate capability, with a close to 100% detection efficiency. In view of the high luminosity phase of the CERN Large Hadron Collider, these aforementioned features make GEMs suitable candidates for the future upgrades of the Compact Muon Solenoid (CMS) detector. In particular, the CMS GEM Collaboration proposes to cover the high-eta region of the muon system with large-area triple-GEM detectors, which have the ability to provide robust and redundant tracking and triggering functions. In this contribution, after a general introduction and overview of the project, the construction of full-size trapezoidal triple-GEM prototypes will be described in more detail. The procedures for the quality control of the GEM foils, including gain uniformity measurements with an x-ray source will be presented. In the past few years, several CMS triple-GEM prototype detectors were operated with test beams at the CERN SPS. The results of these test beam campaigns will be summarised.

  9. Mountain Gem Russet: A medium to late season potato variety with high early and full season yield potential and excellent fresh market characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mountain Gem Russet is a medium to late maturing variety with both high early and full season yields of oblong-long, medium-russeted tubers having higher protein content than those of standard potato varieties. Mountain Gem Russet has greater resistance to tuber late blight, tuber malformations and ...

  10. The promotion of gonadal cell divisions by the Caenorhabditis elegans TRPM cation channel GON-2 is antagonized by GEM-4 copine.

    PubMed Central

    Church, Diane L; Lambie, Eric J

    2003-01-01

    The initiation of postembryonic cell divisions by the gonadal precursors of C. elegans requires the activity of gon-2. gon-2 encodes a predicted cation channel (GON-2) of the TRPM subfamily of TRP proteins and is likely to mediate the influx of Ca(2+) and/or Mg(2+). We report here that mutations in gem-4 (gon-2 extragenic modifier) are capable of suppressing loss-of-function alleles of gon-2. gem-4 encodes a member of the copine family of Ca(2+)-dependent phosphatidylserine binding proteins. Overall, our data indicate that GEM-4 antagonizes GON-2. This antagonism could be mediated by a direct inhibition of GON-2 by GEM-4, since both proteins are predicted to be localized to the plasma membrane. Alternatively, GEM-4 could affect GON-2 activity levels by either promoting endocytosis or inhibiting exocytosis of vesicles that carry GON-2. It is also possible that GEM-4 and GON-2 act in parallel to each other. Mutation of gem-4 does not suppress the gonadal defects produced by inactivation of gon-4, suggesting that gon-4 either acts downstream of gem-4 and gon-2 or acts in a parallel regulatory pathway. PMID:14573470

  11. Resolution dependence in simulating the African hydroclimate with the HadGEM3-RA regional climate model

    NASA Astrophysics Data System (ADS)

    Moufouma-Okia, W.; Jones, R.

    2015-02-01

    This study documents the effect of horizontal resolution on the ability of the Met Office third-generation Global Atmosphere Regional Climate Model (HadGEM3-RA), a regional atmospheric configuration of the HadGEM3 model, to simulate rainfall variability over Africa. It is based on six 20-year long RCM simulations driven by ERA-Interim reanalysis and performed at 12, 25, 50, 70, 90, and 150 km over the CORDEX-Africa domain. To gain further insight into model errors, we also compared the HadGEM3-RA's performance to that of the parent General Circulation Model using three different spatial resolutions (70, 100, and 150 km), and to HadRM3P—the current Met Office regional climate model. It is found that the 50 km resolution RCM reproduces reasonably the spatial and temporal features of rainfall variability across regions. These include the seasonal progression of the tropical rainbelt, its extent and location, the annual cycle and interannual variability. Although model biases vary across seasons and locations, a prominent feature is the over-prediction of rainfall totals over Central Africa, and underestimation of rainfall in coastal areas of the Guinea Gulf during boreal spring and autumn. HadGEM3-RA improves with increased horizontal resolution, but some model errors persist. Comparison with the parent global model simulations demonstrates generally a realistic and consistent behaviour over large scales—suggesting that the physical formulation is able to capture the key driving processes, but also confirms the benefit of increasing the model horizontal resolution. Despite the model errors, HadGEM3-RA rainfall shows superiority over that from HadRM3P, ERA-Interim and MERRA datasets—indicating that the associated dynamical features of HadGEM3-RA can complement the physical understanding gained from reanalyses. This article also highlights the challenges for evaluating climate models in data sparse regions where satellite derived rainfall and gridded observational

  12. Gillespie eco-evolutionary models (GEMs) reveal the role of heritable trait variation in eco-evolutionary dynamics.

    PubMed

    DeLong, John P; Gibert, Jean P

    2016-02-01

    Heritable trait variation is a central and necessary ingredient of evolution. Trait variation also directly affects ecological processes, generating a clear link between evolutionary and ecological dynamics. Despite the changes in variation that occur through selection, drift, mutation, and recombination, current eco-evolutionary models usually fail to track how variation changes through time. Moreover, eco-evolutionary models assume fitness functions for each trait and each ecological context, which often do not have empirical validation. We introduce a new type of model, Gillespie eco-evolutionary models (GEMs), that resolves these concerns by tracking distributions of traits through time as eco-evolutionary dynamics progress. This is done by allowing change to be driven by the direct fitness consequences of model parameters within the context of the underlying ecological model, without having to assume a particular fitness function. GEMs work by adding a trait distribution component to the standard Gillespie algorithm - an approach that models stochastic systems in nature that are typically approximated through ordinary differential equations. We illustrate GEMs with the Rosenzweig-MacArthur consumer-resource model. We show not only how heritable trait variation fuels trait evolution and influences eco-evolutionary dynamics, but also how the erosion of variation through time may hinder eco-evolutionary dynamics in the long run. GEMs can be developed for any parameter in any ordinary differential equation model and, furthermore, can enable modeling of multiple interacting traits at the same time. We expect GEMs will open the door to a new direction in eco-evolutionary and evolutionary modeling by removing long-standing modeling barriers, simplifying the link between traits, fitness, and dynamics, and expanding eco-evolutionary treatment of a greater diversity of ecological interactions. These factors make GEMs much more than a modeling advance, but an important

  13. Superfund Record of Decision (EPA Region 2): Gloucester Environmental Management Services (GEMS) Landfill, Gloucester Township, Camden County, New Jersey, September 1985. Final report

    SciTech Connect

    Not Available

    1985-09-27

    The 60-acre GEMS Landfill site is located in Gloucester Township, New Jersey. Gloucester Township has owned the GEMS site from the late 1950's up to the present. During the time period the GEMS Landfill has been operated by various parties as a disposal site for solid, liquid, and hazardous wastes and substances. Records indicate that a variety of industrial wastes including asbestos, solvents and other materials were disposed of at the GEMS site between 1970 and 1979. In 1980, sludge from the City of Philadelphia's northeast wastewater treatment facility was disposed of at GEMS. Analyses of the sludge revealed the presence of dichlorodiphenyl dichloroethane (DDD). The results of the RI show that ground water, surface water (Holly Run) and soil are severely contaminated with organic and inorganic hazardous substances. Also, volatile organic compounds are volatilizing into the atmosphere and significantly degrading air quality.

  14. A verification of the gyrokinetic microstability codes GEM, GYRO, and GS2

    NASA Astrophysics Data System (ADS)

    Bravenec, R. V.; Chen, Y.; Candy, J.; Wan, W.; Parker, S.

    2013-10-01

    A previous publication [R. V. Bravenec et al., Phys. Plasmas 18, 122505 (2011)] presented favorable comparisons of linear frequencies and nonlinear fluxes from the Eulerian gyrokinetic codes gyro [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] and gs2 [W. Dorland et al., Phys. Rev. Lett. 85, 5579 (2000)]. The motivation was to verify the codes, i.e., demonstrate that they correctly solve the gyrokinetic-Maxwell equations. The premise was that it is highly unlikely for both codes to yield the same incorrect results. In this work, we add the Lagrangian particle-in-cell code gem [Y. Chen and S. Parker, J. Comput. Phys. 220, 839 (2007)] to the comparisons, not simply to add another code, but also to demonstrate that the codes' algorithms do not matter. We find good agreement of gem with gyro and gs2 for the plasma conditions considered earlier, thus establishing confidence that the codes are verified and that ongoing validation efforts for these plasma parameters are warranted.

  15. A verification of the gyrokinetic microstability codes GEM, GYRO, and GS2

    SciTech Connect

    Bravenec, R. V.; Chen, Y.; Wan, W.; Parker, S.; Candy, J.

    2013-10-15

    A previous publication [R. V. Bravenec et al., Phys. Plasmas 18, 122505 (2011)] presented favorable comparisons of linear frequencies and nonlinear fluxes from the Eulerian gyrokinetic codes gyro[J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] and gs2[W. Dorland et al., Phys. Rev. Lett. 85, 5579 (2000)]. The motivation was to verify the codes, i.e., demonstrate that they correctly solve the gyrokinetic-Maxwell equations. The premise was that it is highly unlikely for both codes to yield the same incorrect results. In this work, we add the Lagrangian particle-in-cell code gem[Y. Chen and S. Parker, J. Comput. Phys. 220, 839 (2007)] to the comparisons, not simply to add another code, but also to demonstrate that the codes' algorithms do not matter. We find good agreement of gem with gyro and gs2 for the plasma conditions considered earlier, thus establishing confidence that the codes are verified and that ongoing validation efforts for these plasma parameters are warranted.

  16. Benchmarking of the Gyrokinetic Microstability Codes GYRO, GS2, and GEM

    NASA Astrophysics Data System (ADS)

    Bravenec, Ronald; Chen, Yang; Wan, Weigang; Parker, Scott; Candy, Jeff; Barnes, Michael; Howard, Nathan; Holland, Christopher; Wang, Eric

    2012-10-01

    The physics capabilities of modern gyrokinetic microstability codes are now so extensive that they cannot be verified fully for realistic tokamak plasmas using purely analytic approaches. Instead, verification (demonstrating that the codes correctly solve the gyrokinetic-Maxwell equations) must rely on benchmarking (comparing code results for identical plasmas and physics). Benchmarking exercises for a low-power DIII-D discharge at the mid-radius have been presented recently for the Eulerian codes GYRO and GS2 [R.V. Bravenec, J. Candy, M. Barnes, C. Holland, Phys. Plasmas 18, 122505 (2011)]. This work omitted ExB flow shear, but we include it here. We also present GYRO/GS2 comparisons for a high-power Alcator C-Mod discharge. To add further confidence to the verification exercises, we have recently added the particle-in-cell (PIC) code GEM to the efforts. We find good agreement of linear frequencies between GEM and GYRO/GS2 for the DIII-D plasma. We also present preliminary nonlinear comparisons. This benchmarking includes electromagnetic effects, plasma shaping, kinetic electrons and one impurity. In addition, we compare linear results among the three codes for the steep-gradient edge region of a DIII-D plasma between edge-localized modes.

  17. The GEM (Gravity-Electro-Magnetism) Theory of Field Unification: Experimental Progress

    NASA Astrophysics Data System (ADS)

    Brandenburg, J. E.

    2006-01-01

    Experimental progress on the GEM (Gravity-Electro-Magnetism) unification theory is summarized as applied to human flight and dynamically modified gravity fields and waves. A VBE (``Vacuum Bernoulli Equation'') is derived. This shows Gravitational energy density to be equated to an EM dynamic pressure that is quadratic in the local Poynting Flux: g2/(2π G) + S2/(c2 L)= Constant, where g and S are the local gravity and Poynting vector magnitudes, respectively, and where L is the Lagrangian density of the vacuum EM field. The VBE can be used to understand anomalous weight loss reported in gyroscope experiments and to understand possible gravity modification for human flight. The GEM gravity modification theory is extended to predict a VHE (Vacuum Hall Effect). Methods for creating dynamic gravity fields via VHE for production and detection of high frequency gravity fields involve electric quadrapole fields normal to static magnetic fields. Earlier experiments at 400Hz had seen lifting effects, however, only when a certain field threshold was crossed. An experiment was performed using 60Hz three phase rotating fields but no effects were seen in low frequency fields thus it appears threshold effects in field intensity and frequency may have been seen.

  18. Prototype of a Muon Tomography Station with GEM detectors for Detection of Shielded Nuclear Contraband

    NASA Astrophysics Data System (ADS)

    Staib, Michael; Bhopatkar, Vallary; Bittner, William; Hohlmann, Marcus; Locke, Judson; Twigger, Jessie; Gnanvo, Kondo

    2012-03-01

    Muon tomography for homeland security aims at detecting well-shielded nuclear contraband in cargo and imaging it in 3D. The technique exploits multiple scattering of atmospheric cosmic ray muons, which is stronger in dense, high-Z materials, e.g. enriched uranium, than in low-Z and medium-Z shielding materials. We have constructed and are operating a compact Muon Tomography Station (MTS) that tracks muons with eight 30 cm x 30 cm Triple Gas Electron Multiplier (GEM) detectors placed on the sides of a cubic-foot imaging volume. A point-of-closest-approach algorithm applied to reconstructed incident and exiting tracks is used to create a tomographic reconstruction of the material within the active volume. We discuss the performance of this MTS prototype including characterization and commissioning of the GEM detectors and the data acquisition systems. We also present experimental tomographic images of small high-Z objects including depleted uranium with and without shielding and discuss the performance of material discrimination using this method.

  19. Development of GEM Tracker for the J-PARC E16 experiment

    NASA Astrophysics Data System (ADS)

    Obara, Yuki; J-PARC E16 Collaboration

    2014-09-01

    A GEM Tracker (GTR) is a micro-pattern gas detector using GEM foils for tracking charged particles. In the J-PARC E16 experiment, momenta of electrons and positrons from decays of the ϕ meson are measured by three layers of the GTRs whose sizes are 100 × 100 , 200 × 200 , and 300 × 300mm2 in a magnetic field. In order to achieve a mass resolution of 5MeV /c2 , position resolutions of 100 μm in a bending direction by the magnetic field and 700 μm in a direction perpendicular to the bending plane are required. Note that an incident angle of charged tracks to the GTR in the bending plane is up to 30°. To cope with the inclined tracks, a new analysis method called ``timing method'' was developed. We have developed GTRs satisfying the requirements and evaluated their performance, such as a position resolution and detection efficiency, by beam tests. Incident angle dependencies of the evaluated items for all sizes of the GTRs were obtained as the test results. We are ready to start a final detector production for the GTRs. In this presentation, we report our GTRs and the achieved performance.

  20. THE SHAPE OF LONG OUTBURSTS IN U GEM TYPE DWARF NOVAE FROM AAVSO DATA

    SciTech Connect

    Cannizzo, John K.

    2012-10-01

    We search the American Association of Variable Star Observers (AAVSO) archives of the two best-studied dwarf novae in an attempt to find light curves for long outbursts that are extremely well characterized. The systems are U Gem and SS Cyg. Our goal is to search for embedded precursors such as those that have been found recently in the high-fidelity Kepler data for superoutbursts (SOs) of some members of the SU UMa subclass of dwarf novae. For the vast majority of AAVSO data, the combination of low data cadence and large errors associated with individual measurements precludes one from making any strong statement about the shape of the long outbursts. However, for a small number of outbursts, extensive long-term monitoring with digital photometry yields high-fidelity light curves. We report the discovery of embedded precursors in two of three candidate long outbursts. This is the first time that such embedded precursors have been found in dwarf novae above the period gap in other than kepler data, and reinforces van Paradijs' finding that long outbursts in dwarf novae above the period gap and SOs in systems below the period gap constitute a unified class. The thermal-tidal instability to account for SOs in the SU UMa stars predicts embedded precursors only for short orbital period dwarf novae, therefore the presence of embedded precursors in long orbital period systems-U Gem and SS Cyg-argues for a more general mechanism to explain long outbursts.

  1. The Shape of Long Outbursts in U Gem Type Dwarf Novae from AAVSO Data

    NASA Technical Reports Server (NTRS)

    Cannizzo, John K.

    2012-01-01

    We search the American Association of Variable Star Observers (AAVSO) archives of the two best studied dwarf novae in an attempt to find light curves for long out bursts that are extremely well-characterized. The systems are U Gem and S8 Cyg. Our goal is to search for embedded precursors such as those that have been found recently in the high fidelity Kepler data for superoutbursts of some members of the 8U UMa subclass of dwarf novae. For the vast majority of AAV80 data, the combination of low data cadence and large errors associated with individual measurements precludes one from making any strong statement about the shape of the long outbursts. However, for a small number of outbursts, extensive long term monitoring with digital photometry yields high fidelity light curves. We report the finding of embedded precursors in two of three candidate long outbursts. This reinforces van Paradijs' finding that long outbursts in dwarf novae above the period gap and superoutbursts in systems below the period gap constitute a unified class. The thermal-tidal instability to account for superoutbursts in the SU UMa stars predicts embedded precursors only for short orbital period dwarf novae, therefore the presence of embedded precursors in long orbital period systems - U Gem and SS Cyg - argues for a more general mechanism to explain long outbursts.

  2. Mcidas and GemC1/Lynkeas specify embryonic radial glial cells.

    PubMed

    Kyrousi, Christina; Lalioti, Maria-Eleni; Skavatsou, Eleni; Lygerou, Zoi; Taraviras, Stavros

    2016-01-01

    Ependymal cells are multiciliated cells located in the wall of the lateral ventricles of the adult mammalian brain and are key components of the subependymal zone niche, where adult neural stem cells reside. Through the movement of their motile cilia, ependymal cells control the cerebrospinal fluid flow within the ventricular system from which they receive secreted molecules and morphogens controlling self-renewal and differentiation decisions of adult neural stem cells. Multiciliated ependymal cells become fully differentiated at postnatal stages however they are specified during mid to late embryogenesis from a population of radial glial cells. Here we discuss recent findings suggesting that 2 novel molecules, Mcidas and GemC1/Lynkeas are key players on radial glial specification to ependymal cells. Both proteins were initially described as cell cycle regulators revealing sequence similarity to Geminin. They are expressed in radial glial cells committed to the ependymal cell lineage during embryogenesis, while overexpression and knock down experiments showed that are sufficient and necessary for ependymal cell generation. We propose that Mcidas and GemC1/Lynkeas are key components of the molecular cascade that promotes radial glial cells fate commitment toward multiciliated ependymal cell lineage operating upstream of c-Myb and FoxJ1. PMID:27606337

  3. Evaluation of the GEM-AQ simulations for the Air Quality Model Evaluation International Initiative (AQMEII)

    NASA Astrophysics Data System (ADS)

    Lobocki, Lech; Gawuc, Lech; Jefimow, Maciej; Kaminski, Jacek; Porebska, Magdalena; Struzewska, Joanna; Zdunek, Malgorzata

    2013-04-01

    A multiscale, on-line meteorological and air quality model GEM-AQ was used to simulate ozone and particulate matter over the European continent in 2006, as a part of the Air Quality Model Evaluation International Initiative (AQMEII). In contrast to the majority of models participating in the Phase I of AQMEII, the GEM-AQ configuration employed here utilized neither external meteorological fields nor lateral boundary conditions, owing to the global-extent and variable grid resolution of the model setup. We will present evaluation results for global model performance statistics calculated for the entire year and more detailed performance analysis of pollution episodes. Evaluation of meteorological parameters includes comparisons of model-predicted wind, temperature and cloudiness with hourly observations at surface weather stations, daily maxima, and comparison with upper-air soundings at selected sites. Frequency distribution of principal boundary layer parameters and its spatial structure will be presented. Air quality predictions are assessed in terms of ground-level daily mean ozone concentrations and its daily peak values, vertical structure as inferred from ozone soundings, and particulate matter daily mean concentrations at the surface.

  4. Identification of stratospheric intrusion mechanisms over Europe - analysis of GEM-AQ model simulations for 2006

    NASA Astrophysics Data System (ADS)

    Porebska, M.; Zdunek, M.; Kaminski, J.; Struzewska, J.; Lobocki, L.

    2012-04-01

    Stratosphere-troposphere exchange processes influence greatly the composition of the upper troposphere. Filamentary structures containing air originating from the stratosphere can remain in the upper and middle part of troposphere for several days due to relatively weak mixing. Synoptic conditions favourable to stratospheric intrusions occur quite often over the North Atlantic and Europe; however, only a small number of intrusions is detected by routine radiosonde/ozonesonde measurements, rather incidentally. The reported research aims at supplementing the existing knowledge by a systematic, one-year modelling study. The tool used here is the GEM-AQ, an on-line atmospheric chemistry model coupled with the Global Multiscale Environmental (GEM) model used for operational weather prediction by Environment Canada. In this study, a global variable resolution grid was used, with horizontal resolution over Europe at about ~20 km. The model was integrated on 28 hybrid levels, with the top at 10 hPa. We will present selected cases of stratospheric intrusion as identified in modelling results. Intrusions are classified into several types, depending on the underlying physical scenario (e.g. tropopause folding near the polar front, cutoff lows, various mesoscale processes). A comparison of model forecasts with measurements and objective analysis, where possible, is presented in order to quantify the predictive model capabilities. Further, an algorithm of intrusion detection based on model results will be presented and several possible options will be compared.

  5. Factorial validation of a walking safety scale (GEM scale) for the geriatric population.

    PubMed

    Dubé, François; Rousseau, Jacqueline; Nadeau, Sylvie; Kaegi, Christine; Boudreault, Renee

    2010-04-22

    The GEM scale is an objective assessment tool evaluating walking safety of elderly individuals. It includes 33 walking items divided into three subscales (A, B, and C). The purpose of this study was to estimate the internal consistency and factorial validation of the scale. Seventy-four subjects (> or = 65 years) recruited from geriatric units were assessed by a total of 11 physical therapists. The internal consistency data were analyzed by using the Cronbach alpha coefficient. An exploratory factor analysis was performed to analyze the factorial structure of the scale and determine the construct validation. The internal consistency for the three subscales revealed high Cronbach alpha (subscales A = 0.90; B = 0.76, and C = 0.85). The preliminary analyses of the factorial validation did not confirm the original structure of the scale. For subscales A and B, a three-factor solution was supported by the analyses and explained 61% of the total variance. For subscale C, a four-factor solution was extracted and explained 87% of the total variance. The three subscales showed excellent item homogeneity. The factorial validation results support a new structure for the GEM scale regrouping the items in two sub-scales under different factors. The reorganization of the walking items into representative factors will allow a better understanding and interpretation of the scale. PMID:20331374

  6. TPC-like readout for thermal neutron detection using a GEM-detector

    NASA Astrophysics Data System (ADS)

    Flierl, B.; Hertenberger, R.; Biebel, O.; Zeitelhack, K.

    2016-07-01

    Spatial resolution of less than 200 μm is challenging for thermal neutron detection. A novel readout scheme based on the time-projection-chamber (TPC) concept is used in a gaseous electron multiplier (GEM) detector [1]. Thermal neutrons are captured in a single 2 μm thick Boron-10 converter cathode and secondary Helium and Lithium ions are produced with a combined energy of 2.8 MeV. These ions have sufficient energy to form straight tracks of several mm length. With a time resolving 2-dimensional readout of 400 μm pitch in both directions, based on APV25 chips, the ions are tracked and their respective origin in the cathode converter foil is reconstructed. Using an Ar-CO2 93:7% gas mixture, a resolution of 100 μm (FWHM 235 μm) has been observed with a triple GEM-detector setup at the Garching neutron source (FRMII) for neutrons of 4.7 Å.

  7. Development studies for the ILC: Measurements and simulations for a time projection chamber with GEM technology

    NASA Astrophysics Data System (ADS)

    Ledermann, Bernhard; Kaminski, Jochen; Kappler, Steffen; Müller, Thomas

    2007-10-01

    A Time Projection Chamber (TPC) with Gas Electron Multiplier (GEM) technology is well suited for usage as central tracker at the International Linear Collider (ILC). To study the high potential of this detector type a small prototype of 25 cm length was built in Karlsruhe and used in several experimental setups. In this publication the results of these measurements and of additional Monte Carlo simulations are presented. By introducing the so-called equivalent drift distance a combination of all results was possible leading to a recommended configuration of the multi-GEM tower for the ILC-TPC. It will be shown that for conditions considered in the TESLA-TDR the transverse spatial resolution will be able to reach 65 μm for 10 cm and 190 μm for 200 cm drift at the ILC. This as well as the expectations for longitudinal spatial resolution, for energy resolutions of the specific ionization, and for single pad row efficiency should be able to meet the requirements of a future ILC-TPC.

  8. Prototype sector magnets for the GeV electron microtron (GEM)

    SciTech Connect

    Wehrle, R.B.; Norem, J.H.; Praeg, W.F.; Swanstrom, R.H.; Thompson, K.M.

    1983-01-01

    Three prototypes of the sector magnets for GeV Electon Microtron accelerators have been designed. One has been built and two are being constructed. The first is a full scale, 168 ton prototype for one-half of a 2 GeV Double Sided Microtron (DSM) sector magnet. The successful fabrication and testing of the pole pieces for this prototype has demonstrated that their required close tolerances for flatness and parallelism can be met. The second magnet is an approximate two-thirds scale model of one step at the low energy end of the hexatron sector magnet designed for the 4 GeV Electron Microtron (GEM). The measured fields demonstrate that the field falls off faster than an Enge-short-tail and error fields are at low levels and are controllable. A third prototype magnet exactly duplicates the full scale geometry of the first three full orbits of the GEM sector magnet from entrance to exit points. It will permit high precision measurements and corrections of field errors and verify the 3-D computer program, TOSCA.

  9. Trace elemental analysis of Indian natural moonstone gems by PIXE and XRD techniques.

    PubMed

    Venkateswara Rao, R; Venkateswarulu, P; Kasipathi, C; Sivajyothi, S

    2013-12-01

    A selected number of Indian Eastern Ghats natural moonstone gems were studied with a powerful nuclear analytical and non-destructive Proton Induced X-ray Emission (PIXE) technique. Thirteen elements, including V, Co, Ni, Zn, Ga, Ba and Pb, were identified in these moonstones and may be useful in interpreting the various geochemical conditions and the probable cause of their inceptions in the moonstone gemstone matrix. Furthermore, preliminary XRD studies of different moonstone patterns were performed. The PIXE technique is a powerful method for quickly determining the elemental concentration of a substance. A 3MeV proton beam was employed to excite the samples. The chemical constituents of moonstones from parts of the Eastern Ghats geological formations of Andhra Pradesh, India were determined, and gemological studies were performed on those gems. The crystal structure and the lattice parameters of the moonstones were estimated using X-Ray Diffraction studies, trace and minor elements were determined using the PIXE technique, and major compositional elements were confirmed by XRD. In the present work, the usefulness and versatility of the PIXE technique for research in geo-scientific methodology is established. PMID:24055999

  10. The MIT / NASA Langley Magnetic Suspension/Balance System

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A shuttle model is magnetically suspended in the transparent octagonal test section of the MIT / NASA Langley 6 Inch MSBS. Massive power supplies are required to drive electromagnets for model position control. A unique electromagnetic position sensor, similar to a linear variable differential transformer, provides five degrees of freedom for the test model. The low speed (Mach 0.5) wind tunnel was hand crafted from mahogany. Aerodynamic forces on the test model are measured by the proportional electrical current used to hold the model in place. The system was built by MIT in the late sixties and was relocated to Langley in the mid eighties. In a joint effort with Old Dominion University in 1992 the MSBS was used to test the aerodynamics of store separation, simulating a bomb released from an aircraft. The system has been donated to Old Dominion University.

  11. MIT LMFBR blanket research project. Final summary report

    SciTech Connect

    Driscoll, M.J.

    1983-08-01

    This is a final summary report on an experimental and analytical program for the investigation of LMFBR blanket characteristics carried out at MIT in the period 1969 to 1983. During this span of time, work was carried out on a wide range of subtasks, ranging from neutronic and photonic measurements in mockups of blankets using the Blanket Test Facility at the MIT Research Reactor, to analytic/numerical investigations of blanket design and economics. The main function of this report is to serve as a resource document which will permit ready reference to the more detailed topical reports and theses issued over the years on the various aspects of project activities. In addition, one aspect of work completed during the final year of the project, on doubly-heterogeneous blanket configurations, is documented for the record.

  12. The Harvard-MIT PHD Program in Bioastronautics

    NASA Astrophysics Data System (ADS)

    Young, Laurence R.; Natapoff, Alan

    2008-06-01

    The National Space Biomedical Research Institute (NSBRI)1 supports a PhD program in Space Life Sciences with a specialty in Bioastronautics at MIT. (A sibling program operates at TAMU.) It gives broad training in life sciences, emphasizes hands-on field experience, provides access to laboratories in the Harvard-MIT community for thesis research, and prepares students for many options in space biomedicine. The Program trains prospective leaders in the field able to manage the challenges of design for the life-hostile space environment. Beyond subject and thesis work, students participate in a summer internship and a clinical preceptorship at a NASA center--and an introduction to clinical medicine and medical engineering.

  13. Optimal spectral resolution for NO2 and SO2 retrieval by Geostationary Environmental Monitoring Spectrometer (GEMS)

    NASA Astrophysics Data System (ADS)

    Chong, J.; Kim, Y. J.; Scientific Team of DOAS

    2011-12-01

    Ministry of Environment, Korea is planning an environmental geostationary satellite program as a part of MP-GEOSAT (Multi-Purpose GEOstationary SATellite), which is scheduled to be launched in 2017 (Lee S. et al., 2010). It is supposed to be placed on an orbit of approximately 36,000 kilometers high directly over the equator, which revolves in the same direction the earth rotates. Its missions include meteorological, ocean monitoring, and environmental monitoring. Especially, Geostationary Environmental Monitoring Spectrometer (GEMS) is to provide atmospheric chemistry measurements of trace gases such as O3, NO2, SO2, HCHO, and aerosol in high temporal (every 1 hour) and spatial (30x30 km2) resolution over Asia, to monitor regional transport events such as transboundary pollution and Asian dust, and to enhance our understanding on interactions between atmospheric chemistry and meteorology. In order to determine the minimum required spectral resolution of GEMS, measurement accuracy has been estimated for different spectral resolutions based on the actual satellite data as well as model simulation data of very fine spectral resolution. Absorption spectra of SCIAMACHY level 2 data (http://www.temis.nl) with spectral resolution of 0.2nm and reconstructed spectra of broader spectral resolution; 0.4, 0.6, and 0.8nm have been utilized to assess the applicability for SO2 and NO2 retrievals over GEMS spatial coverage areas using the DOAS fitting method. The relative fitting error in SO2 retrieval of each spectral resolution over southern China was determined to be 45.1, 56.1, 99.7, and 187.3 %, respectively. The relative fitting errors in NO2 retrieval of each spectral resolution over northern India were 16.2, 24.6, 32.6, and 38.9 %, respectively. Since relative fitting error in SO2 retrieval increases as the spectra resolution increases, the optimal spectrum resolution was determined to be 0.4nm. On the other hand, since the relative fitting error in NO2 retrieval is below

  14. Stationäre Motorvermessung mit verschiedenen Methoden und Modellen

    NASA Astrophysics Data System (ADS)

    Kötter, Hinrich; Sequenz, Heiko

    Die kontinuierliche Verschärfung der gesetzlichen Vorgaben bezüglich Emissionen stellt die Motorenentwickler vor neue Herausforderungen (Bild 6-1, [1, 2]). Gleichzeitig ist zu erwarten, dass sich der langfristige Trend der letzten Jahren bei den Kraftstoffpreisen [3] trotz kurzzeitiger Schwankungen fortsetzen wird (Bild 6-1 rechts, Jahresmittelwerte). Auf die steigenden Kraftstoffpreise sowie die Verpflichtungen bezüglich der CO2- Emissionswerte kann dauerhaft nur mit Kraftstoff sparenden Motoren reagiert werden.

  15. Hidden Gems

    ERIC Educational Resources Information Center

    Leventhal, Jerome I.

    2004-01-01

    When a program is approved for state/federal subsidy in the field of career and technical education, there is always a record on file with information about the program in the state education department. These records are for program approval, funding, status reports, or final reports. In the big picture of programs in the field of education,…

  16. 'Gem' pear

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Gem’ is a new cultivar which combines excellent appearance, fruit quality and long storage potential with precocious and high yields. It can be eaten without ripening due to a crisp, juicy texture, as well as ripened to a soft texture. ‘Gem’ was jointly released by the U. S. Department of Agricul...

  17. Favourite Gems

    ERIC Educational Resources Information Center

    Barnes, John

    2011-01-01

    Mathematics is full of surprises and beauty. In this article, the author discusses three favourite topics that he finds both amazing and amusing: (1) the problem of the possibility of subdividing a rectangle into a number of different squares; (2) the arrangement formed when several soap bubbles meet; and (3) circles and spheres.

  18. Selective synthesis of gem-chlorofluorinated nitrogen-containing derivatives after superelectrophilic activation in superacid HF/SbF5.

    PubMed

    Liu, Fei; Martin-Mingot, Agnès; Jouannetaud, Marie-Paule; Bachmann, Christian; Frapper, Gilles; Zunino, Fabien; Thibaudeau, Sébastien

    2011-03-01

    The first direct selective synthesis of novel gem-chlorofluorinated nitrogen-containing building blocks in superacid is reported. The dramatic role of the chlorine atom on the reaction is shown by in situ NMR experiments and allows the involvement of a novel original superelectrophilic activation process in superacid HF/SbF(5) to be postulated. PMID:21250710

  19. Triple GEM detector sensitivity simulations with Geant4 for the CMS Forward Muon Upgrade at CERN LHC

    NASA Astrophysics Data System (ADS)

    Zenoni, Florian; CMS GEM Collaboration

    2015-04-01

    Triple Gas Electron Multiplier (GEM) detectors are being developed for the forward muon upgrade of the CMS experiment in Phase 2 of the CERN LHC. After the second long LHC shutdown, their implementation will take place for the GE1/1 system in the 1 . 5 < | η | < 2 . 2 region of the muon endcap. This upgrade aims at controlling muon level-1 trigger rates, thanks to their high performance in extreme particle rates (~ MHz/cm2). Moreover, the GEM technology can improve the muon track reconstruction and identification capabilities of the forward detector. The Triple GEMs will work in a hostile radiation background (several hundreds of Hz/cm2) mostly made of photons, neutrons, electrons and positrons. To understand how this background could affect the detectors' functionality it is important to know the sensitivity to these kinds of radiation. The goal of this work is to estimate the sensitivity of Triple GEMs to background particles in the CMS cavern environment, thanks to the latest updates of GEANT4, a toolkit for the simulation of the passage of particles through matter.

  20. Establishing Fair and Realistic Entry and Exit Criteria Using the General Evaluation Matrix (GEM), a Special Education Decision Making Tool.

    ERIC Educational Resources Information Center

    Maxwell, Kenneth G.

    The paper describes the development and use of a General Evaluation Matrix (GEM), a profile technique by which major handicaps are graphically presented along with school grades and achievements in basic skills. The approach lends itself to establishing entry level criteria for special education suited to the needs of specific communities.…

  1. Progress on The GEMS (Gravity Electro-Magnetism-Strong) Theory of Field Unification and Its Application to Space Problems

    SciTech Connect

    Brandenburg, J. E.

    2008-01-21

    Progress on the GEMS (Gravity Electro-Magnetism-Strong), theory is presented as well as its application to space problems. The GEMS theory is now validated through the Standard Model of physics. Derivation of the value of the Gravitation constant based on the observed variation of {alpha} with energy: results in the formula G congruent with ({Dirac_h}/2{pi})c/M{sub {eta}}{sub c}{sup 2} exp(-1/(1.61{alpha})), where {alpha} is the fine structure constant,({Dirac_h}/2{pi}), is Planck's constant, c, is the speed of light, and M{sub {eta}}{sub c} is the mass of the {eta}{sub cc} Charmonium meson that is shown to be identical to that derived from the GEM postulates. Covariant formulation of the GEM theory is now possible through definition of the spacetime metric tensor as a portion of the EM stress tensor normalized by its own trace: g{sub ab} = 4(F{sup c}{sub a}F{sub cb})/(F{sup ab}F{sub ab}), it is found that this results in a massless ground state vacuum and a Newtonian gravitation potential {phi} = 1/2 E{sup 2}/B{sup 2}. It is also found that a Lorentz or flat-space metric is recovered in the limit of a full spectrum ZPF.

  2. PlasmoGEM, a database supporting a community resource for large-scale experimental genetics in malaria parasites.

    PubMed

    Schwach, Frank; Bushell, Ellen; Gomes, Ana Rita; Anar, Burcu; Girling, Gareth; Herd, Colin; Rayner, Julian C; Billker, Oliver

    2015-01-01

    The Plasmodium Genetic Modification (PlasmoGEM) database (http://plasmogem.sanger.ac.uk) provides access to a resource of modular, versatile and adaptable vectors for genome modification of Plasmodium spp. parasites. PlasmoGEM currently consists of >2000 plasmids designed to modify the genome of Plasmodium berghei, a malaria parasite of rodents, which can be requested by non-profit research organisations free of charge. PlasmoGEM vectors are designed with long homology arms for efficient genome integration and carry gene specific barcodes to identify individual mutants. They can be used for a wide array of applications, including protein localisation, gene interaction studies and high-throughput genetic screens. The vector production pipeline is supported by a custom software suite that automates both the vector design process and quality control by full-length sequencing of the finished vectors. The PlasmoGEM web interface allows users to search a database of finished knock-out and gene tagging vectors, view details of their designs, download vector sequence in different formats and view available quality control data as well as suggested genotyping strategies. We also make gDNA library clones and intermediate vectors available for researchers to produce vectors for themselves. PMID:25593348

  3. The general ensemble biogeochemical modeling system (GEMS) and its applications to agriculture systems in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The General Ensemble Biogeochemical Modeling System (GEMS) was developed for a proper integration of well-established ecosystem biogeochemical models with various spatial databases to simulate biogeochemical cycles over large areas. Major driving variables include land cover and land use, climate, s...

  4. IUE observations of two late-type stars Bx Mon (M + pec) and TV Gem (M1 Iab)

    NASA Technical Reports Server (NTRS)

    Michalitsianos, A. G.; Hobbs, R. W.; Kafatos, M.

    1981-01-01

    The IUE observations of two late type stars BX Mon and TV Gem that reveal the emission properties in the ultraviolet of subluminous companions are discussed. Analysis of the continuum emission observed from BX Mon suggests the companion, is a middle A III star. High excitation emission lines observed between 1200 A and 2000 A that generally do not typify emission observed in either late M type variables or A type stars are also detected. It is suggested that these strong high excitation lines arise in a large volume of gas heated by nonradiation processes that could be the result of tidal interaction and mass exchange in the binary system. In contrast to stars such as BX Mon, the luminous M1 supergiant TV Gem shows unexpected intense UV continuum throughout the sensitivity range of IUE. The UV spectrum of TV Gem is characterized by intense continuum with broad absorption features detected in the short wavelength range. The analysis shows that the companion could be a B9 or A1 III-IV star. Alternate suggestions are presented for explaining the UV continuum in terms of an accretion disk in association with TV Gem.

  5. Girls in Engineering, Mathematics and Science, GEMS: A Science Outreach Program for Middle-School Female Students

    ERIC Educational Resources Information Center

    Dubetz, Terry A.; Wilson, Jo Ann

    2013-01-01

    Girls in Engineering, Mathematics and Science (GEMS) is a science and math outreach program for middle-school female students. The program was developed to encourage interest in math and science in female students at an early age. Increased scientific familiarity may encourage girls to consider careers in science and mathematics and will also help…

  6. GEM – Meeting the Challenge of Maize Diversification by Capturing Useful Alleles and Traits from Exotic Germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Germplasm Enhancement of Maize (GEM) Project was conceived as a public and private research partnership dedicated to diversifying the genetic base of U.S. maize production. It is coordinated by USDA-ARS and university personnel located at Iowa State University and North Carolina State University...

  7. Characterization of a GEM-based scintillation detector with He–CF4 gas mixture in clinical proton beams

    NASA Astrophysics Data System (ADS)

    Nichiporov, D.; Coutinho, L.; Klyachko, A. V.

    2016-04-01

    Accurate, high-spatial resolution dosimetry in proton therapy is a time consuming task, and may be challenging in the case of small fields, due to the lack of adequate instrumentation. The purpose of this work is to develop a novel dose imaging detector with high spatial resolution and tissue equivalent response to dose in the Bragg peak, suitable for beam commissioning and quality assurance measurements. A scintillation gas electron multiplier (GEM) detector based on a double GEM amplification structure with optical readout was filled with a He/CF4 gas mixture and evaluated in pristine and modulated proton beams of several penetration ranges. The detector’s performance was characterized in terms of linearity in dose rate, spatial resolution, short- and long-term stability and tissue-equivalence of response at different energies. Depth-dose profiles measured with the GEM detector in the 115–205 MeV energy range were compared with the profiles measured under similar conditions using the PinPoint 3D small-volume ion chamber. The GEM detector filled with a He-based mixture has a nearly tissue equivalent response in the proton beam and may become an attractive and efficient tool for high-resolution 2D and 3D dose imaging in proton dosimetry, and especially in small-field applications.

  8. Characterization of a GEM-based scintillation detector with He-CF4 gas mixture in clinical proton beams.

    PubMed

    Nichiporov, D; Coutinho, L; Klyachko, A V

    2016-04-21

    Accurate, high-spatial resolution dosimetry in proton therapy is a time consuming task, and may be challenging in the case of small fields, due to the lack of adequate instrumentation. The purpose of this work is to develop a novel dose imaging detector with high spatial resolution and tissue equivalent response to dose in the Bragg peak, suitable for beam commissioning and quality assurance measurements. A scintillation gas electron multiplier (GEM) detector based on a double GEM amplification structure with optical readout was filled with a He/CF4 gas mixture and evaluated in pristine and modulated proton beams of several penetration ranges. The detector's performance was characterized in terms of linearity in dose rate, spatial resolution, short- and long-term stability and tissue-equivalence of response at different energies. Depth-dose profiles measured with the GEM detector in the 115-205 MeV energy range were compared with the profiles measured under similar conditions using the PinPoint 3D small-volume ion chamber. The GEM detector filled with a He-based mixture has a nearly tissue equivalent response in the proton beam and may become an attractive and efficient tool for high-resolution 2D and 3D dose imaging in proton dosimetry, and especially in small-field applications. PMID:26992243

  9. GEnomes Management Application (GEM.app): a new software tool for large-scale collaborative genome analysis.

    PubMed

    Gonzalez, Michael A; Lebrigio, Rafael F Acosta; Van Booven, Derek; Ulloa, Rick H; Powell, Eric; Speziani, Fiorella; Tekin, Mustafa; Schüle, Rebecca; Züchner, Stephan

    2013-06-01

    Novel genes are now identified at a rapid pace for many Mendelian disorders, and increasingly, for genetically complex phenotypes. However, new challenges have also become evident: (1) effectively managing larger exome and/or genome datasets, especially for smaller labs; (2) direct hands-on analysis and contextual interpretation of variant data in large genomic datasets; and (3) many small and medium-sized clinical and research-based investigative teams around the world are generating data that, if combined and shared, will significantly increase the opportunities for the entire community to identify new genes. To address these challenges, we have developed GEnomes Management Application (GEM.app), a software tool to annotate, manage, visualize, and analyze large genomic datasets (https://genomics.med.miami.edu/). GEM.app currently contains ∼1,600 whole exomes from 50 different phenotypes studied by 40 principal investigators from 15 different countries. The focus of GEM.app is on user-friendly analysis for nonbioinformaticians to make next-generation sequencing data directly accessible. Yet, GEM.app provides powerful and flexible filter options, including single family filtering, across family/phenotype queries, nested filtering, and evaluation of segregation in families. In addition, the system is fast, obtaining results within 4 sec across ∼1,200 exomes. We believe that this system will further enhance identification of genetic causes of human disease. PMID:23463597

  10. Tapping the Source: A Listing of Groundwater Education Materials Available through the Groundwater Education in Michigan (GEM) Program. Updated.

    ERIC Educational Resources Information Center

    Michigan State Univ., East Lansing. Inst. of Water Research.

    Established in 1988 through the cooperative efforts of the Institute of Water Research at Michigan State University and the W. K. Kellogg Foundation, the Groundwater Education in Michigan (GEM) program helps people understand the relationship between their actions and the quality of their environment, particularly groundwater. The program has a…

  11. Design of a constant fraction discriminator for the VFAT3 front-end ASIC of the CMS GEM detector

    NASA Astrophysics Data System (ADS)

    Abbaneo, D.; Abbas, M.; Abbrescia, M.; Abdelalim, A. A.; Abi Akl, M.; Aboamer, O.; Acosta, D.; Ahmad, A.; Ahmed, W.; Ahmed, W.; Aleksandrov, A.; Aly, R.; Altieri, P.; Asawatangtrakuldee, C.; Aspell, P.; Assran, Y.; Awan, I.; Bally, S.; Ban, Y.; Banerjee, S.; Barashko, V.; Barria, P.; Bencze, G.; Beni, N.; Benussi, L.; Bhopatkar, V.; Bianco, S.; Bos, J.; Bouhali, O.; Braghieri, A.; Braibant, S.; Buontempo, S.; Calabria, C.; Caponero, M.; Caputo, C.; Cassese, F.; Castaneda, A.; Cauwenbergh, S.; Cavallo, F. R.; Celik, A.; Choi, M.; Choi, S.; Christiansen, J.; Cimmino, A.; Colafranceschi, S.; Colaleo, A.; Conde Garcia, A.; Czellar, S.; Dabrowski, M. M.; De Lentdecker, G.; De Oliveira, R.; de Robertis, G.; Dildick, S.; Dorney, B.; Elmetenawee, W.; Endroczi, G.; Errico, F.; Fenyvesi, A.; Ferry, S.; Furic, I.; Giacomelli, P.; Gilmore, J.; Golovtsov, V.; Guiducci, L.; Guilloux, F.; Gutierrez, A.; Hadjiiska, R. M.; Hassan, A.; Hauser, J.; Hoepfner, K.; Hohlmann, M.; Hoorani, H.; Iaydjiev, P.; Jeng, Y. G.; Kamon, T.; Karchin, P.; Korytov, A.; Krutelyov, S.; Kumar, A.; Kim, H.; Lee, J.; Lenzi, T.; Litov, L.; Loddo, F.; Madorsky, A.; Maerschalk, T.; Maggi, M.; Magnani, A.; Mal, P. K.; Mandal, K.; Marchioro, A.; Marinov, A.; Masod, R.; Majumdar, N.; Merlin, J. A.; Mitselmakher, G.; Mohanty, A. K.; Mohamed, S.; Mohapatra, A.; Molnar, J.; Muhammad, S.; Mukhopadhyay, S.; Naimuddin, M.; Nuzzo, S.; Oliveri, E.; Pant, L. M.; Paolucci, P.; Park, I.; Passeggio, G.; Pavlov, B.; Philipps, B.; Piccolo, D.; Postema, H.; Baranac, A. Puig; Radi, A.; Radogna, R.; Raffone, G.; Ranieri, A.; Rashevski, G.; Riccardi, C.; Rodozov, M.; Rodrigues, A.; Ropelewski, L.; RoyChowdhury, S.; Ryu, G.; Ryu, M. S.; Safonov, A.; Salva, S.; Saviano, G.; Sharma, A.; Sharma, A.; Sharma, R.; Shah, A. H.; Shopova, M.; Sturdy, J.; Sultanov, G.; Swain, S. K.; Szillasi, Z.; Talvitie, J.; Tamma, C.; Tatarinov, A.; Tuuva, T.; Tytgat, M.; Vai, I.; Van Stenis, M.; Venditti, R.; Verhagen, E.; Verwilligen, P.; Vitulo, P.; Volkov, S.; Vorobyev, A.; Wang, D.; Wang, M.; Yang, U.; Yang, Y.; Yonamine, R.; Zaganidis, N.; Zenoni, F.; Zhang, A.

    2016-01-01

    In this work the design of a constant fraction discriminator (CFD) to be used in the VFAT3 chip for the read-out of the triple-GEM detectors of the CMS experiment, is described. A prototype chip containing 8 CFDs was implemented using 130 nm CMOS technology and test results are shown.

  12. Gem1 and ERMES Do Not Directly Affect Phosphatidylserine Transport from ER to Mitochondria or Mitochondrial Inheritance

    PubMed Central

    Nguyen, Tammy T; Lewandowska, Agnieszka; Choi, Jae-Yeon; Markgraf, Daniel F; Junker, Mirco; Bilgin, Mesut; Ejsing, Christer S; Voelker, Dennis R; Rapoport, Tom A; Shaw, Janet M

    2012-01-01

    In yeast, a protein complex termed the ER-Mitochondria Encounter Structure (ERMES) tethers mitochondria to the endoplasmic reticulum. ERMES proteins are implicated in a variety of cellular functions including phospholipid synthesis, mitochondrial protein import, mitochondrial attachment to actin, polarized mitochondrial movement into daughter cells during division, and maintenance of mitochondrial DNA (mtDNA). The mitochondrial-anchored Gem1 GTPase has been proposed to regulate ERMES functions. Here, we show that ERMES and Gem1 have no direct role in the transport of phosphatidylserine (PS) from the ER to mitochondria during the synthesis of phosphatidylethanolamine (PE), as PS to PE conversion is not affected in ERMES or gem1 mutants. In addition, we report that mitochondrial inheritance defects in ERMES mutants are a secondary consequence of mitochondrial morphology defects, arguing against a primary role for ERMES in mitochondrial association with actin and mitochondrial movement. Finally, we show that ERMES complexes are long-lived, and do not depend on the presence of Gem1. Our findings suggest that the ERMES complex may have primarily a structural role in maintaining mitochondrial morphology. PMID:22409400

  13. Application of the GEM Inventory Data Capture Tools for Dynamic Vulnerability Assessment and Recovery Modelling

    NASA Astrophysics Data System (ADS)

    Verrucci, Enrica; Bevington, John; Vicini, Alessandro

    2014-05-01

    A set of open-source tools to create building exposure datasets for seismic risk assessment was developed from 2010-13 by the Inventory Data Capture Tools (IDCT) Risk Global Component of the Global Earthquake Model (GEM). The tools were designed to integrate data derived from remotely-sensed imagery, statistically-sampled in-situ field data of buildings to generate per-building and regional exposure data. A number of software tools were created to aid the development of these data, including mobile data capture tools for in-field structural assessment, and the Spatial Inventory Data Developer (SIDD) for creating "mapping schemes" - statistically-inferred distributions of building stock applied to areas of homogeneous urban land use. These tools were made publically available in January 2014. Exemplar implementations in Europe and Central Asia during the IDCT project highlighted several potential application areas beyond the original scope of the project. These are investigated here. We describe and demonstrate how the GEM-IDCT suite can be used extensively within the framework proposed by the EC-FP7 project SENSUM (Framework to integrate Space-based and in-situ sENSing for dynamic vUlnerability and recovery Monitoring). Specifically, applications in the areas of 1) dynamic vulnerability assessment (pre-event), and 2) recovery monitoring and evaluation (post-event) are discussed. Strategies for using the IDC Tools for these purposes are discussed. The results demonstrate the benefits of using advanced technology tools for data capture, especially in a systematic fashion using the taxonomic standards set by GEM. Originally designed for seismic risk assessment, it is clear the IDCT tools have relevance for multi-hazard risk assessment. When combined with a suitable sampling framework and applied to multi-temporal recovery monitoring, data generated from the tools can reveal spatio-temporal patterns in the quality of recovery activities and resilience trends can be

  14. Oxygen isotope systematics of gem corundum deposits in Madagascar: relevance for their geological origin

    NASA Astrophysics Data System (ADS)

    Giuliani, Gaston; Fallick, Anthony; Rakotondrazafy, Michel; Ohnenstetter, Daniel; Andriamamonjy, Alfred; Ralantoarison, Théogène; Rakotosamizanany, Saholy; Razanatseheno, Marie; Offant, Yohann; Garnier, Virginie; Dunaigre, Christian; Schwarz, Dietmar; Mercier, Alain; Ratrimo, Voahangy; Ralison, Bruno

    2007-02-01

    The oxygen isotopic composition of gem corundum was measured from 22 deposits and occurrences in Madagascar to provide a gemstone geological identification and characterization. Primary corundum deposits in Madagascar are hosted in magmatic (syenite and alkali basalt) and metamorphic rocks (gneiss, cordieritite, mafic and ultramafic rocks, marble, and calc-silicate rocks). In both domains the circulation of fluids, especially along shear zones for metamorphic deposits, provoked in situ transformation of the corundum host rocks with the formation of metasomatites such as phlogopite, sakenite, and corundumite. Secondary deposits (placers) are the most important economically and are contained in detrital basins and karsts. The oxygen isotopic ratios (18O/16O) of ruby and sapphire from primary deposits are a good indicator of their geological origin and reveal a wide range of δ18O (Vienna Standard Mean Ocean Water) between 1.3 and 15.6‰. Metamorphic rubies are defined by two groups of δ18O values in the range of 1.7 to 2.9‰ (cordieritite) and 3.8 to 6.1‰ (amphibolite). “Magmatic” rubies from pyroxenitic xenoliths contained in the alkali basalt of Soamiakatra have δ18O values ranging between 1.3 and 4.7‰. Sapphires are classified into two main groups with δ18O in the range of 4.7 to 9.0‰ (pyroxenite and feldspathic gneiss) and 10.7 to 15.6‰ (skarn in marble from Andranondambo). The δ18O values for gem corundum from secondary deposits have a wide spread between -0.3 and 16.5‰. The ruby and sapphire found in placers linked to alkali basalt environments in the northern and central regions of Madagascar have consistent δ18O values between 3.5 and 6.9‰. Ruby from the placers of Vatomandry and Andilamena has δ18O values of 5.9‰, and between 0.5 and 4.0‰, respectively. The placers of the Ilakaka area are characterized by a huge variety of colored sapphires and rubies, with δ18O values between -0.3 and 16.5‰, and their origin is debated. A

  15. 5-Exo-cyclizations of pentenyliminyl radicals: inversion of the gem-dimethyl effect.

    PubMed

    Portela-Cubillo, Fernando; Alonso-Ruiz, Rafael; Sampedro, Diego; Walton, John C

    2009-09-17

    This paper describes how the rates of 5-exo-ring closures of unsaturated iminyl radicals to pyrrolomethyl radicals respond to substituents in the pentenyl chain and at the C=N bond. Benzyl- and acyl oxime esters, as well as dioxime oxalates, were identified as suitable iminyl radical sources for electron paramagnetic resonance (EPR) spectroscopy. Pentenyliminyl radicals with aryl substituents at their C=N bonds, and one with an alkyl substituent at its C=N bond, were studied in solution by steady-state continuous wave EPR spectroscopy. All the pentenyliminyls selectively ring closed in the 5-exo-mode rather than the 6-endo-mode. EPR monitoring of the decay of the 2,2-dimethyl-1-phenylpent-4-enyliminyl radical showed that it underwent bimolecular combination at about the diffusion controlled limit (2kt approximately 3 x 10(8) M(-1) s(-1) at 245 K). The rate constant for 5-exo-ring closure of phenylpentenyliminyl (8.8 x 10(3) s(-1) at 300 K) was a factor of 25 smaller than the rate constant for hex-5-enyl radical cyclization. The rate of cyclization was slower for an iminyl having a Me group at the site of 5-exo-cyclization but faster for an iminyl with an Et substituent at the terminus of the C=C double bond. Surprisingly, the 2,2-dimethyl-1-phenylpent-4-enyliminyl radical, with a bismethyl group in its pentenyl chain, ring closed more slowly than the unsubstituted analogue. DFT computations were in accord with this inverse gem-dimethyl effect and suggested it resulted from steric interaction of the Ph and bis-Me groups which forced the aromatic ring out of the plane of the imine moiety. To check on the role of the Ph substituent, pentenyliminyls lacking this group were sought. A pentenyliminyl radical with an alkyl group in place of the Ph group, and a single Me group in its pentenyl chain, was generated by means of an unsymmetrical dioxime oxalate precursor. The k(c) for this species was a factor of 2.5 larger than k(c) for the original pentenyliminyl, suggesting

  16. 5-Exo-Cyclizations of Pentenyliminyl Radicals: Inversion of the gem-Dimethyl Effect

    NASA Astrophysics Data System (ADS)

    Portela-Cubillo, Fernando; Alonso-Ruiz, Rafael; Sampedro, Diego; Walton, John C.

    2009-08-01

    This paper describes how the rates of 5-exo-ring closures of unsaturated iminyl radicals to pyrrolomethyl radicals respond to substituents in the pentenyl chain and at the C═N bond. Benzyl- and acyl oxime esters, as well as dioxime oxalates, were identified as suitable iminyl radical sources for electron paramagnetic resonance (EPR) spectroscopy. Pentenyliminyl radicals with aryl substituents at their C═N bonds, and one with an alkyl substituent at its C═N bond, were studied in solution by steady-state continuous wave EPR spectroscopy. All the pentenyliminyls selectively ring closed in the 5-exo-mode rather than the 6-endo-mode. EPR monitoring of the decay of the 2,2-dimethyl-1-phenylpent-4-enyliminyl radical showed that it underwent bimolecular combination at about the diffusion controlled limit (2kt ˜ 3 × 108 M-1 s-1 at 245 K). The rate constant for 5-exo-ring closure of phenylpentenyliminyl (8.8 × 103 s-1 at 300 K) was a factor of 25 smaller than the rate constant for hex-5-enyl radical cyclization. The rate of cyclization was slower for an iminyl having a Me group at the site of 5-exo-cyclization but faster for an iminyl with an Et substituent at the terminus of the C═C double bond. Surprisingly, the 2,2-dimethyl-1-phenylpent-4-enyliminyl radical, with a bismethyl group in its pentenyl chain, ring closed more slowly than the unsubstituted analogue. DFT computations were in accord with this inverse gem-dimethyl effect and suggested it resulted from steric interaction of the Ph and bis-Me groups which forced the aromatic ring out of the plane of the imine moiety. To check on the role of the Ph substituent, pentenyliminyls lacking this group were sought. A pentenyliminyl radical with an alkyl group in place of the Ph group, and a single Me group in its pentenyl chain, was generated by means of an unsymmetrical dioxime oxalate precursor. The kc for this species was a factor of 2.5 larger than kc for the original pentenyliminyl, suggesting that the normal

  17. Application of the GEM-T2 gravity field to altimetric satellite orbit computation

    NASA Technical Reports Server (NTRS)

    Haines, Bruce J.; Born, George H.; Williamson, Ronald G.; Koblinsky, Chester I.

    1994-01-01

    As part of a continuing effort to provide improved orbits for use with existing altimeter data, we have recomputed ephemerides for both the Seasat and Geosat Exact Repeat altimeter missions. The orbits were computed in a consistent fashion, using the Goddard Earth Model T2 (GEM-T2) gravity field along with available ground-based tracking data. Such an approach allows direct comparisons of sea level between the two altimeter systems. Evaluation of the resulting ephemerides indicates that root-mean-square accuracies of 30-50 cm have been achieved for the radial component of the orbits for both satellites. An exception occurs for the last year of the Geosat Exact Repeat Mission, when the rms radial orbit accuracy degrades to the 1-m level at times owing to the inability to adequately model the drag force arising from the increased solar activity.

  18. Design and optimization of resistive anode for a two-dimensional imaging GEM detector

    NASA Astrophysics Data System (ADS)

    Ju, Xu-Dong; Dong, Ming-Yi; Zhao, Yi-Chen; Zhou, Chuan-Xing; Qun, Ou-Yang

    2016-08-01

    A resistive anode for two-dimensional imaging detectors, which consists of a series of high resistivity pads surrounded by low resistivity strips, can provide good spatial resolution while reducing the number of electronics channels required. The optimization of this kind of anode has been studied by both numerical simulations and experimental tests. It is found that to obtain good detector performance, the resistance ratio of the pads to the strips should be larger than 5, the nonuniformity of the pad surface resistivity should be less than 20%, a smaller pad width leads to a smaller spatial resolution, and when the pad width is 6 mm, the spatial resolution (σ) can reach about 105 μm. Based on the study results, a 2-D GEM detector prototype with optimized resistive anode is constructed and a good imaging performance is achieved. Supported by National Natural Science Foundation of China (11375219) and CAS Center for Excellence in Particle Physics (CCEPP)

  19. C-4 gem-dimethylated oleanes of Gymnema sylvestre and their pharmacological activities.

    PubMed

    Di Fabio, Giovanni; Romanucci, Valeria; Zarrelli, Mauro; Giordano, Michele; Zarrelli, Armando

    2013-01-01

    Gymnema sylvestre R. Br., one of the most important medicinal plants of the Asclepiadaceae family, is a herb distributed throughout the World, predominantly in tropical countries. The plant, widely used for the treatment of diabetes and as a diuretic in Indian proprietary medicines, possesses beneficial digestive, anti-inflammatory, hypoglycemic and anti-helmentic effects. Furthermore, it is believed to be useful in the treatment of dyspepsia, constipation, jaundice, hemorrhoids, cardiopathy, asthma, bronchitis and leucoderma. A literature survey revealed that some other notable pharmacological activities of the plant such as anti-obesity, hypolipidemic, antimicrobial, free radical scavenging and anti-inflammatory properties have been proven too. This paper aims to summarize the chemical and pharmacological reports on a large group of C-4 gem-dimethylated pentacyclic triterpenoids from Gymnema sylvestre. PMID:24304585

  20. A multi-channel readout electronics system for GEM and MICROMEGAS

    NASA Astrophysics Data System (ADS)

    Deng, Z.; Li, Y. L.; Gong, G. H.; Gong, H.; Luo, J.; Liu, Y. N.

    2009-11-01

    A multi-channel readout electronics system for GEM and MICROMEGAS has been developed. It consists of a front-end ASIC, a multi-channel ADC and a FPGA to sample the signal waveforms in real time. The gain of the front-end ASIC can be programmable from 1 mV/fC to 19 mV/fC and the output pulse width can be adjusted from 200 ns to 800 ns. The ENC is measured to be below 2000 e for Cin < 20 pF and below 5000 e for Cin < 60 pF. Detailed circuit performance and test results with detectors will be described in this paper.

  1. Tomographic capabilities of the new GEM based SXR diagnostic of WEST

    NASA Astrophysics Data System (ADS)

    Jardin, A.; Mazon, D.; O'Mullane, M.; Mlynar, J.; Loffelmann, V.; Imrisek, M.; Chernyshova, M.; Czarski, T.; Kasprowicz, G.; Wojenski, A.; Bourdelle, C.; Malard, P.

    2016-07-01

    The tokamak WEST (Tungsten Environment in Steady-State Tokamak) will start operating by the end of 2016 as a test bed for the ITER divertor components in long pulse operation. In this context, radiative cooling of heavy impurities like tungsten (W) in the Soft X-ray (SXR) range [0.1 keV; 20 keV] is a critical issue for the plasma core performances. Thus reliable tools are required to monitor the local impurity density and avoid W accumulation. The WEST SXR diagnostic will be equipped with two new GEM (Gas Electron Multiplier) based poloidal cameras allowing to perform 2D tomographic reconstructions in tunable energy bands. In this paper tomographic capabilities of the Minimum Fisher Information (MFI) algorithm developed for Tore Supra and upgraded for WEST are investigated, in particular through a set of emissivity phantoms and the standard WEST scenario including reconstruction errors, influence of noise as well as computational time.

  2. The 2.3 GHz continuum survey of the GEM project

    NASA Astrophysics Data System (ADS)

    Tello, C.; Villela, T.; Torres, S.; Bersanelli, M.; Smoot, G. F.; Ferreira, I. S.; Cingoz, A.; Lamb, J.; Barbosa, D.; Perez-Becker, D.; Ricciardi, S.; Currivan, J. A.; Platania, P.; Maino, D.

    2013-08-01

    Context. Determining the spectral and spatial characteristics of the radio continuum of our Galaxy is an experimentally challenging endeavour for improving our understanding of the astrophysics of the interstellar medium. This knowledge has also become of paramount significance for cosmology, since Galactic emission is the main source of astrophysical contamination in measurements of the cosmic microwave background (CMB) radiation on large angular scales. Aims: We present a partial-sky survey of the radio continuum at 2.3GHz within the scope of the Galactic Emission Mapping (GEM) project, an observational program conceived and developed to reveal the large-scale properties of Galactic synchrotron radiation through a set of self-consistent surveys of the radio continuum between 408MHz and 10GHz. Methods: The GEM experiment uses a portable and double-shielded 5.5-m radiotelescope in altazimuthal configuration to map 60-degree-wide declination bands from different observational sites by circularly scanning the sky at zenithal angles of 30° from a constantly rotating platform. The observations were accomplished with a total power receiver, whose front-end high electron mobility transistor (HEMT) amplifier was matched directly to a cylindrical horn at the prime focus of the parabolic reflector. The Moon was used to calibrate the antenna temperature scale and the preparation of the map required direct subtraction and destriping algorithms to remove ground contamination as the most significant source of systematic error. Results: We used 484 h of total intensity observations from two locations in Colombia and Brazil to yield 66% sky coverage from to . The observations in Colombia were obtained with a horizontal HPBW of and a vertical HPBW of . The pointing accuracy was and the RMS sensitivity was 11.42 mK. The observations in Brazil were obtained with a horizontal HPBW of and a vertical HPBW of . The pointing accuracy was and the RMS sensitivity was 8.24 mK. The zero

  3. Jefferson Laboratory Hall A SuperBigBite spectrometer GEM readout scheme

    NASA Astrophysics Data System (ADS)

    Camsonne, Alexandre; Hall A SuperBigBite Collaboration

    2015-10-01

    The SuperBigBite spectrometer at Jefferson Laboratory in Hall A will rely on Gas Electron Multiplier trackers to achieve the required luminosity for large momentum transfer experiments. The readout electronics is based on the APV25 ASIC and the INFN VME board Multi Purpose Digitizer (MPD) Board. By using the optical readout of readout of the boards, all boards can be readout in parallel effectively increasing the data bandwidth for one crate by more than a factor of 10. With such scheme the readout of several samples become possible and background rejection can be applied to reduce the large quantity of data due to the high occupancy of detector before it is recorded. This special readout scheme based on the JLab electronics will be presented along with the online data reduction strategy for the GEM data.

  4. Re-investigation of the Ponzio reaction for the preparation of gem-dinitro compounds

    SciTech Connect

    Honey, P.J.; Millar, R.W.; Coombes, R.G.

    1995-12-01

    Many aromatic nitro compounds can be prepared using mixtures of nitric and sulphuric acids, but, this medium usually results in the destruction of the substrate for aliphatic compounds. Hence a variety of less aggressive nitrating agents in nonacidic media are employed. This talk presents some recent work to re-investigate the Ponzio reaction for the conversion of oximes to the gem-nitro group. The effect of varying the reaction media, and of changing the nitrating species from N{sub 2}O{sub 4} to N{sub 2}O{sub 5} will also be presented. The reaction mechanism will be discussed with reference to CIDNP nmr studies. Where relevant the results will be compared with other aliphatic nitration methods.

  5. Conceptual design and development of GEM based detecting system for tomographic tungsten focused transport monitoring

    NASA Astrophysics Data System (ADS)

    Chernyshova, M.; Czarski, T.; Malinowski, K.; Kowalska-Strzęciwilk, E.; Poźniak, K.; Kasprowicz, G.; Zabołotny, W.; Wojeński, A.; Kolasiński, P.; Mazon, D.; Malard, P.

    2015-10-01

    Implementing tungsten as a plasma facing material in ITER and future fusion reactors will require effective monitoring of not just its level in the plasma but also its distribution. That can be successfully achieved using detectors based on Gas Electron Multiplier (GEM) technology. This work presents the conceptual design of the detecting unit for poloidal tomography to be tested at the WEST project tokamak. The current stage of the development is discussed covering aspects which include detector's spatial dimensions, gas mixtures, window materials and arrangements inside and outside the tokamak ports, details of detector's structure itself and details of the detecting module electronics. It is expected that the detecting unit under development, when implemented, will add to the safe operation of tokamak bringing the creation of sustainable nuclear fusion reactors a step closer. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

  6. Simulation of the time-projection chamber with triple GEMs for the LAMPS at RAON

    NASA Astrophysics Data System (ADS)

    Jhang, Genie; Lee, Jung Woo; Moon, Byul; Hong, Byungsik; Ahn, Jung Keun; Lee, Jong-Won; Lee, Kyong Sei; Kim, Young Jin; Lee, Hyo Sang

    2016-03-01

    The time-projection chamber (TPC) with triple gas-electron multipliers (GEMs) is designed for the large-acceptance multipurpose spectrometer (LAMPS) at the new radioactive ion-beam facility RAON, a pure Korean term for the accelerator complex, in Korea. The simulation environment has been set up to test the performance of the designed chamber, and the software package for analysis has been developed. Particle identification has been demonstrated to be possible up to 2 GeV/ c in momentum for particles with the charge number 1 and 2 by using the simulated heavy-ion events. The transverse-momentum resolutions are expected to be about 2% for protons and about 1.3% for pions in the relatively high-momentum region. The total reconstruction efficiencies are estimated to be about 90 and 80% for charged pions and protons, respectively.

  7. 3D field calculation of the GEM prototype magnet and comparison with measurements

    SciTech Connect

    Lari, R.J.

    1983-10-28

    The proposed 4 GeV Electron Microtron (GEM) is designed to fill the existing buildings left vacant by the demise of the Zero Gradient Synchrotron (ZGS) accelerator. One of the six large dipole magnets is shown as well as the first 10 electron orbits. A 3-orbit prototype magnet has been built. The stepped edge of the magnet is to keep the beam exiting perpendicular to the pole. The end guards that wrap around the main coils are joined together by the 3 shield plates. The auxiliary coils are needed to keep the end guards and shield plates from saturating. A 0.3 cm Purcell filter air gap exists between the pole and the yoke. Can anyone question this being a truly three-dimensional magnetostatic problem. The computer program TOSCA, developed at the Rutherford Appleton Laboratory by the Computing Applications Group, was used to calculate this magnet and the results have been compared with measurements.

  8. Non-adiabatic response of relativistic radiation belt electrons to GEM magnetic storms

    NASA Astrophysics Data System (ADS)

    McAdams, K. L.; Reeves, G. D.

    The importance of fully adiabatic effects in the relativistic radiation belt electron response to magnetic storms is poorly characterized due to many difficulties in calculating adiabatic flux response. Using the adiabatic flux model of Kim and Chan [1997a] and Los Alamos National Laboratory geosynchronous satellite data, we examine the relative timing of the adiabatic and non-adiabatic flux responses. In the three storms identified by the GEM community for in depth study, the non-adiabatic energization occurs hours earlier than the adiabatic re-energization. The adiabatic energization can account for only 10-20% of the flux increases in the first recovery stages, and only 1% of the flux increase if there is continuing activity.

  9. A cylindrical GEM detector with analog readout for the BESIII experiment

    NASA Astrophysics Data System (ADS)

    Amoroso, A.; Baldini, R.; Bertani, M.; Bettoni, D.; Bianchi, F.; Calcaterra, A.; Carassiti, V.; Cerioni, S.; Chai, J.; Cibinetto, G.; Cotto, G.; Mori, F. De; Destefanis, M.; Dong, J.; Dong, M.; Farinelli, R.; Fava, L.; Felici, G.; Fioravanti, E.; Garzia, I.; Gatta, M.; Greco, M.; Hu, J. F.; Johansson, T.; Leng, C.; Li, H.; Liu, Z.; Maggiora, M.; Marcello, S.; Marciniewski, P.; Melchiorri, M.; Mezzadri, G.; Morello, G.; Ouyan, Q.; Pacetti, S.; Patteri, P.; Rivetti, A.; Rosner, C.; Savrié, M.; Sosio, S.; Spataro, S.; Tskhadadze, E.; Wang, K.; Wang, L.; Wu, L.; Ji, X.; Ye, M.; Zallo, A.; Zhang, Y.; Zotti, L.

    2016-07-01

    A cylindrical GEM detector with analog readout is under development for the upgrade of the Inner Tracker of the BESIII experiment at IHEP (Beijing). The new detector will match the requirements for momentum resolution (σpt /pt ~ 0.5 % at 1 GeV) and radial resolution (σxy ~ 120 μm) of the existing drift chamber and will improve significantly the spatial resolution along the beam direction (σz ~ 150 μm) with very small material budget (less than 1.5% of X0). With respect to the state of the art the following innovations will be deployed: a lighter mechanical structure based on Rohacell, a new XV anode readout plane with jagged strip layout to reduce the parasitic capacitance, and the use of the analogue readout inside a high intensity magnetic field to have good spatial resolution without increasing the number of channels.

  10. The Australian bush fires of February 2009: MIPAS observations and GEM-AQ model results

    NASA Astrophysics Data System (ADS)

    Glatthor, N.; Höpfner, M.; Semeniuk, K.; Lupu, A.; Palmer, P. I.; McConnell, J. C.; Kaminski, J. W.; von Clarmann, T.; Stiller, G. P.; Funke, B.; Kellmann, S.; Linden, A.; Wiegele, A.

    2012-06-01

    On 7 February 2009, and the following days Southeast Australia was devastated by large bush fires, which burned an area of about 3000 km2. This event was extraordinary, because a large number of combustion products was transported into the uppermost troposphere and lower stratosphere within a few days. Various biomass burning products released by the fire were observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on the ENVISAT satellite. We track the plume using MIPAS C2H2, HCN and HCOOH single-scan measurements on a day-to-day basis. The measurements are compared with a high-resolution model run of the Global Environmental Multiscale-Air Quality (GEM-AQ) model. Generally there is very good agreement between the spatial distribution of measured and modelled pollutants during the first two weeks after the outbreak of the fire even over intercontinental distances. Both MIPAS and GEM-AQ show a fast south-eastward transport of the pollutants to New Zealand within one day. During the following 3-4 days the plume was located north and eastward of New Zealand and centered at altitudes of 15 to 18 km. Thereafter its eastern part was transported eastward at altitudes of 15-16 km, followed by westward transport of its western part at somewhat higher altitudes. On 17 February the eastern part had reached Southern South America and on 20 February the South African west coast. On the latter day a second relic of the plume was observed moving eastward above the Southern Pacific, whereas the westward transported pollutants were located above Australia at altitudes of 18-20 km. First evidence for entry of the pollutants into the stratosphere was found in MIPAS data of 11 February, followed by larger amounts on 17 February and the days thereafter. Between 20 February and the first week of March the stratospheric pollutants above Australia were transported further westward over the Indian Ocean towards Southern Africa.

  11. Cause and effect considerations in diagnostic pathology and pathology phenotyping of genetically engineered mice (GEM).

    PubMed

    McKerlie, Colin

    2006-01-01

    Over the next several decades, biology is embarking on its most ambitious project yet: to annotate the human genome functionally, prioritizing and focusing on those genes relevant to development and disease. Model systems are fundamental prerequisites for this task, and genetically engineered mice (GEM) are by far the most accessible mammalian system because of their anatomical, physiological, and genetic similarity to humans. The scientific utility of GEM has become commonplace since the technology to produce them was established in the early 1980s. Conceptually, however, an efficiently coordinated high-throughput approach that permits correlation between newly discovered genes, functional properties of their protein products, and biological relevance of these products as drug targets has yet to be established. The discipline of veterinary anatomical pathology (hereafter referred to as pathology) is not immune to this requirement for evolution and adaptation, and to address relationships and tissue consequences between tens of thousands of genes and their cognate proteins, novel interdisciplinary technologies and approaches must emerge. Although many of the techniques of pathology are well established, in the context of pathology's contribution to functional annotation of the genome, several conceptually important and unresolved issues remain to be addressed. While an ever-increasing arsenal of genetic and molecular tool-sets are available to evaluate and understand the function of genes and their pathophysiological mechanisms, pathology will continue to play an essential role in confirming cause and effect relationships of gene function in development and disease. This role will continue to be dependent on keen observation, a systematic but disciplined approach, expert knowledge of strain-dependent anatomical differences and incidental lesions, and relevant tissue-based evidence. Miniaturization and high-throughput adaptation of these methods must also continue

  12. GEM-CEDAR Challenge: Comparing Ionospheric Models with Poynting Flux from DMSP Observations

    NASA Technical Reports Server (NTRS)

    Rastaetter, Lutz; Kuznetsova, Maria; Shim, Ja-Soon; Hesse, Michael; Knipp, Delores J.; Weimer, Daniel R.; Fuller-Rowell, Timothy J.; Ridley, Aaron J.; Raeder, Joachim; Maruyama, Naomi; Kilcomons, Liam; Wittberger, Michael James

    2011-01-01

    As part to the GEM-CEDAR challenge we are extending the model-data comparisons to electrodynamic in-situ measurements in low-Earth orbit. We use DMSP observations of electric and magnetic fields to compute Poynting Flux values along the satellite track in high latitudes including the auroral zones and the polar cap. Models of the ionosphere that include electrodynamic parameters have been run for five events selected for the GEM-CEDAR modeling challenge for which DMSP data are available for comparison. Combined with a magnetic field model we use the modeled electric fields to compute Poynting Flux and Joule Dissipation values from outputs of CTIPe, TIE-GCM, the ionospheric electrodynamics solvers of the SWMF, LFM and OpenGGCM magnetosphere-ionosphere coupled models, and the Weimer electric field model. The online metrics analysis tool at the Community Coordinated Modeling Center (CCMC) has been updated to handle the analysis of separate short segments of available data (high-latitude sections of the satellite orbit) with model outputs to analyze how well auroral patterns are being reproduced by the models. We present initial results from the new analysis tool in terms of model yields (ratio of the difference between maximum and minimum values of model results to the observation), timing/location errors of local maxima in the inbound and outbound auroral crossings as well as cross-correlations for individual passes. We collect the information for many DMSP passes and present an analysis for model performance during quiet and geomagnetically disturbed time periods using half-orbit integrated values as well.

  13. Dst Index in the 2008 GEM Modeling Challenge - Model Performance for Moderate and Strong Magnetic Storms

    NASA Technical Reports Server (NTRS)

    Rastaetter, Lutz; Kuznetsova, Maria; Hesse, Michael; Chulaki, Anna; Pulkkinen, Antti; Ridley, Aaron J.; Gombosi, Tamas; Vapirev, Alexander; Raeder, Joachim; Wiltberger, Michael James; Mays, M. L.; Fok, Mei-Ching H.; Weigel, Robert S.; Welling, Daniel T.

    2010-01-01

    The GEM 2008 modeling challenge efforts are expanding beyond comparing in-situ measurements in the magnetosphere and ionosphere to include the computation of indices to be compared. The Dst index measures the largest deviations of the horizontal magnetic field at 4 equatorial magnetometers from the quiet-time background field and is commonly used to track the strength of the magnetic disturbance of the magnetosphere during storms. Models can calculate a proxy Dst index in various ways, including using the Dessler-Parker Sckopke relation and the energy of the ring current and Biot-Savart integration of electric currents in the magnetosphere. The GEM modeling challenge investigates 4 space weather events and we compare models available at CCMC against each other and the observed values of Ost. Models used include SWMF/BATSRUS, OpenGGCM, LFM, GUMICS (3D magnetosphere MHD models), Fok-RC, CRCM, RAM-SCB (kinetic drift models of the ring current), WINDMI (magnetosphere-ionosphere electric circuit model), and predictions based on an impulse response function (IRF) model and analytic coupling functions with inputs of solar wind data. In addition to the analysis of model-observation comparisons we look at the way Dst is computed in global magnetosphere models. The default value of Dst computed by the SWMF model is for Bz the Earth's center. In addition to this, we present results obtained at different locations on the Earth's surface. We choose equatorial locations at local noon, dusk (18:00 hours), midnight and dawn (6:00 hours). The different virtual observatory locations reveal the variation around the earth-centered Dst value resulting from the distribution of electric currents in the magnetosphere during different phases of a storm.

  14. Impact Features on Europa: Results of the Galileo Europa Mission (GEM)

    NASA Astrophysics Data System (ADS)

    Moore, J. M.; Asphaug, E.; Morrison, D.; Sullivan, R. J.; Chapman, C. R.; Greeley, R.; Klemaszewski, J. E.; Kadel, S.; Chuang, F.; Moreau, J.; Williams, K. K.; Geissler, P. E.; McEwen, A. S.; Turtle, E. A.; Phillips, C. B.; Tufts, B. R.; Head, J. W.; Pappalardo, R. T.; Collins, G. C.; Neukum, G.; Wagner, R.; Klaasen, K. P.; Breneman, H. H.; McGee, K. P.; Senske, D. A.; Granahan, J.; Belton, M. J. S.; Galileo SSI Team

    1998-09-01

    The Galileo Orbiter, during the GEM phase of this mission, has examined a number of impact features on Europa at considerably better resolution and coverage than was possible from either Voyager or during the Galileo nominal mission. The new data allow us to describe the morphology and infer the geology of the largest impact features on Europa, which are probes into the crust. The GEM observations allow us to construct a suite of primary impact features on Europa; a comprehensive "family" portrait and ordering (by size on one axis and morphologic variations within a given size bin along the other). We have also made detailed description of individual impact features including topography (from stereo), crater-related materials deposits, cross-cutting relations, and material-related color variations. We observe two basic types of large impact features: (1) "classic" impact craters that grossly resemble well-preserved lunar craters of similar size but are more topographically subdued (e.g., Pwyll); and (2) very flat circular features that lack the basic topographic structures of impact craters such as raised rims, a central depression, or central peaks, and which largely owe their identification as impact features to the field of secondary craters radially sprayed about them (e.g., Callanish). One of our preliminary conclusions are that Callanish and Tyre display non-"classic" impact features morphologies and a series of large concentric structural rings cutting impact-feature-related materials. Impact simulations suggest that Callanish and Tyre would not be produced by impact into a solid ice target, but may be explained by impact into an ice layer 10 to 15 km thick overlying a low viscosity material such as water.

  15. Comments on the MIT Assessment of the Mars One Plan

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2015-01-01

    The MIT assessment of the Mars One mission plan reveals design assumptions that would cause significant difficulties. Growing crops in the crew chamber produces excessive oxygen levels. The assumed in-situ resource utilization (ISRU) equipment has too low a Technology Readiness Level (TRL). The required spare parts cause a large and increasing launch mass logistics burden. The assumed International Space Station (ISS) Environmental Control and Life Support (ECLS) technologies were developed for microgravity and therefore are not suitable for Mars gravity. Growing food requires more mass than sending food from Earth. The large number of spares is due to the relatively low reliability of ECLS and the low TRL of ISRU. The Mars One habitat design is similar to past concepts but does not incorporate current knowledge. The MIT architecture analysis tool for long-term settlements on the Martian surface includes an ECLS system simulation, an ISRU sizing model, and an analysis of required spares. The MIT tool showed the need for separate crop and crew chambers, the large spare parts logistics, that crops require more mass than Earth food, and that more spares are needed if reliability is lower. That ISRU has low TRL and ISS ECLS was designed for microgravity are well known. Interestingly, the results produced by the architecture analysis tool - separate crop chamber, large spares mass, large crop chamber mass, and low reliability requiring more spares - were also well known. A common approach to ECLS architecture analysis is to build a complex model that is intended to be all-inclusive and is hoped will help solve all design problems. Such models can struggle to replicate obvious and well-known results and are often unable to answer unanticipated new questions. A better approach would be to survey the literature for background knowledge and then directly analyze the important problems.

  16. The MIT TEAL Simulations and Visualizations in Electromagnetism

    NASA Astrophysics Data System (ADS)

    Belcher, John

    2007-03-01

    The Technology Enabled Active Learning (TEAL) Project at MIT has developed a broad range of 3D visualizations and simulations to foster student intuition about electromagnetic fields and phenomena (see http://web.mit.edu/8.02t/www/802TEAL3D/). In this talk we discuss the software approaches we use to create these simulations, including Macromedia Shockwave and Java 3D applets for interactive visualization, passive animations created with 3ds max, and the Dynamic Line Integral Convolution (DLIC) method for constructing time dependent representations of the electromagnetic field at close to the resolution of the computer display (Sundquist, 2003). The DLIC method, in particular, is far superior in delineating the spatial and temporal structure of fields as compared to e.g. field line displays or vector field grids. We also report on the use of these visualizations in instruction at the freshmen level. Our strong opinion is that for effective student learning, such visualizations must be embedded in a software framework for their interactive delivery. This ``guided inquiry'' framework is essential to influence and optimize what students take away from the visualizations. In our current research, we are delivering our visualizations using a commercial package, Addison Wesley's MasteringPhysics (MP), although any guided inquiry delivery system such as MP will be able to interact with our simulation software. We have released our Java 3D simulation software as open source with a liberal open source license (see http://jlearn.mit.edu/tealsim/ ), with support from the Davis Educational Foundation.

  17. Research in Boron Neutron Capture Therapy at MIT LABA

    SciTech Connect

    Yanch, J.C.; Shefer, R.E.; Klinkowstein, R.E.; Howard, W.B.; Song, H.; Blackburn, B.; Binello, E.

    1997-02-01

    A 4.1 MeV tandem electrostatic accelerator designed for research into Boron Neutron Capture Therapy (BNCT) has recently been installed in the MIT Laboratory for Accelerator Beam Applications (LABA). This accelerator uses a very high current switch mode high voltage power supply in conjunction with a multi-cusp negative ion source to supply the multimilliampere current required for clinical BNCT applications. A number of individual research projects aimed at evaluating the potential of this accelerator design as a hospital-based neutron source for radiation therapy of both tumors and rheumatoid arthritis are described here. {copyright} {ital 1997 American Institute of Physics.}

  18. Characteristics of the MIT microwiggler for free electron laser applications

    SciTech Connect

    Catravas, P.; Stoner, R.; Bekefi, G.

    1995-12-31

    We report work on the development of microwiggler technology for free electron laser research. The MIT microwiggler is a pulsed electromagnet with 70 periods of 8.8 mm each which generates a peak on-axis field of 4.2 kG. The wiggler is characterized by extensive tunability. We developed a novel tuning regimen to control 140 degrees of freedom afforded by the individually tunable half periods and achieved an rms spread in the peak amplitudes of 0.08%. This is the lowest attained to date in any sub-cm period wiggler. The microwiggler design and comprehensive measurements of its characteristics will be described.

  19. Sicheres Navigieren in dynamischen Umgebungen mit 3D-Kollisionsvermeidung

    NASA Astrophysics Data System (ADS)

    Stiene, Stefan; Hertzberg, Joachim

    Diese Papier stellt eine neuartige Methode vor, die 3D-Hindernisvermeidung ermöglicht. Die Sensorkonfiguration beruht auf sechs Laserscannern, die die gesamte Roboteroberfläche abdecken. Die Daten der sechs Laserscanner werden zu einem virtuellen, zweidimensionalen, horizontal ausgerichteten 360°-Laserscanner kombiniert. Da der virtuelle Laserscanner die 3D-Umgebung in einem zweidimensionalen Datensatz repräsentiert, ermöglicht er in Kombination mit klassischen Hindernisvermeidungsalgorithmen wie der Vector Field Histogram Methode eine 3D-Hindernisvermeidung.

  20. Synthesis and Electronic Structure of Ru2(Xap)4(Y-gem-DEE) Type Compounds: Effect of Cross-Conjugation.

    PubMed

    Forrest, William P; Choudhuri, Mohommad M R; Kilyanek, Stefan M; Natoli, Sean N; Prentice, Boone M; Fanwick, Phillip E; Crutchley, Robert J; Ren, Tong

    2015-08-01

    Reported in this Article are the preparation and characterization of a series of new Ru2(II,III) compounds bearing one cross-conjugated σ-geminal-diethynylethene ligand (gem-DEE), namely, Ru2(Xap)4(Y-gem-DEE) (Xap = N,N'-anilinopyridinate (ap) or 2-(3,5-dimethoxy)anilinopyridinate (DiMeOap), and Y = Si(i)Pr3 (1) or H (2)) and [Ru2(ap)4]2(μ-gem-DEE) (3). Compounds 1-3 were characterized by spectroscopic and voltammetric techniques as well as the single crystal X-ray diffraction study of 2a. The X-ray structural data of 2a and the spectroscopic/voltammetric data of compounds 1 and 2 indicate that the gem-DEE ligands are similar to simple alkynyls in their effects on the molecular and electronic structures of the Ru2(Xap)4 moiety. Similar to the previously studied [Ru2(ap)4]2(μ-C2n) type compounds, dimer 3 exhibits pairwise 1e(-) oxidations and reductions, albeit the potential splits within the pair (ΔE1/2) are significantly smaller than those of [Ru2(ap)4]2(μ-C4). The electronic absorption spectra of the reduced and oxidized derivatives of 1a and 3 were determined using spectroelectrochemistry methods. No discernible intervalence charge transfer transition (IVCT) was detected in the near-IR spectrum for either 3(-) or 3(+), suggesting that the Ru2-Ru2 coupling in these mixed-valence states is weak. DFT calculations on a model compound of 3 yielded six singly occupied molecular orbitals (SOMOs), which have Ru2 contributions similar to those previously calculated for the [Ru2(ap)4]2(μ-C2n) type compounds. Among six SOMOs, SOMO-2 is the only one containing substantial dπ-π(gem-DEE) character across the entire Ru2-μ-gem-DEE-Ru2 linkage, which explains the weakened Ru2-Ru2 coupling. PMID:26204103

  1. Test beam and irradiation test results of Triple-GEM detector prototypes for the upgrade of the muon system of the CMS experiment

    NASA Astrophysics Data System (ADS)

    Vai, I.

    2016-07-01

    The CMS Collaboration is developing GEM detectors for the upgrade of the CMS muon system. Their performance will be presented, analyzing the results of several test beams and an irradiation test performed in the last years.

  2. Summary final report: Contract between the Japan atomic power company and the U.S. Department of Energy Improvement of core safety - study on GEM (III)

    SciTech Connect

    Burke, T.M.; Lucoff, D.M.

    1997-03-18

    This report provides a summary of activities associated with the technical exchange between representatives of the Japan Atomic Power Company (JAPC) and the United States Department of Energy (DOE) regarding the development and testing of Gas Expansion Modules (GEM) at the Fast Flux Test Facility (FFTF). Issuance of this report completes the scope of work defined in the original contract between JAPC and DOE titled ''Study on Improvement of Core Safety - Study on GEM (III).'' Negotiations related to potential modification of the contract are in progress. Under the proposed contract modification, DOE would provide an additional report documenting FFTF pump start tests with GEMs and answer additional JAPC questions related to core safety with and without GEMs.

  3. Was hat das Universum mit uns zu tun?

    NASA Astrophysics Data System (ADS)

    Lesch, Harald

    Was hat das Universum mit uns zu tun? Da der Mensch ein Teil des Universums ist, muss er etwas mit dem Universum zu tun haben. Das Universum stellt ja ganz allgemein den größten Ursache-Wirkung-Zusammenhang dar, über den hinaus zwar noch gedacht und gerechnet, aber nichts mehr beobachtet oder gemessen werden kann. Es definiert also nicht nur die Möglichkeiten materiell-energetischer Seinsformen sondern auch deren Grenzen. Leben, bzw. menschliches Leben stellt im Universum dann zwar eine spezielle Form, aber eben nur eine Form materieller Daseinsstruktur dar. Neben Galaxien, Gas, Sternen, Planeten, Asteroiden und anderen Formen unbelebter Materie gibt es eben auch noch Lebewesen. Das klingt nach Inventur, nach Aufzählung ohne Unterschied. Diese einfache erste Betrachtung liefert vielleicht die ein oder andere Anregung für ein weiteres Suchen nach Substanzen, aber ein wesentliches Moment geht hier verloren. Ich meine die empirische, sehr gut abgesicherte Tatsache, dass das Universum, wie alles was es enthält, eine Entwicklung durchlaufen hat und auch weiterhin durchläuft - nennen wir diese Entwicklung die kosmische Evolution.

  4. MIT image reconstruction based on edge-preserving regularization.

    PubMed

    Casanova, R; Silva, A; Borges, A R

    2004-02-01

    Tikhonov regularization has been widely used in electrical tomography to deal with the ill-posedness of the inverse problem. However, due to the fact that discontinuities are strongly penalized, this approach tends to produce blurred images. Recently, a lot of interest has been devoted to methods with edge-preserving properties, such as those related to total variation, wavelets and half-quadratic regularization. In the present work, the performance of an edge-preserving regularization method, called ARTUR, is evaluated in the context of magnetic induction tomography (MIT). ARTUR is a deterministic method based on half-quadratic regularization, where complementary a priori information may be introduced in the reconstruction algorithm by the use of a nonnegativity constraint. The method is first tested using an MIT analytical model that generates projection data given the position, the radius and the magnetic permeability of a single nonconductive cylindrical object. It is shown that even in the presence of strong Gaussian additive noise, it is still able to recover the main features of the object. Secondly, reconstructions based on real data for different configurations of conductive nonmagnetic cylindrical objects are presented and some of their parameters estimated. PMID:15005316

  5. DynaMIT: the dynamic motif integration toolkit

    PubMed Central

    Dassi, Erik; Quattrone, Alessandro

    2016-01-01

    De-novo motif search is a frequently applied bioinformatics procedure to identify and prioritize recurrent elements in sequences sets for biological investigation, such as the ones derived from high-throughput differential expression experiments. Several algorithms have been developed to perform motif search, employing widely different approaches and often giving divergent results. In order to maximize the power of these investigations and ultimately be able to draft solid biological hypotheses, there is the need for applying multiple tools on the same sequences and merge the obtained results. However, motif reporting formats and statistical evaluation methods currently make such an integration task difficult to perform and mostly restricted to specific scenarios. We thus introduce here the Dynamic Motif Integration Toolkit (DynaMIT), an extremely flexible platform allowing to identify motifs employing multiple algorithms, integrate them by means of a user-selected strategy and visualize results in several ways; furthermore, the platform is user-extendible in all its aspects. DynaMIT is freely available at http://cibioltg.bitbucket.org. PMID:26253738

  6. Education Outreach at MIT Plasma Science Fusion Center

    NASA Astrophysics Data System (ADS)

    Censabella, V.; Nachtrieb, R.; Rivenberg, P.

    1998-11-01

    Outreach at the MIT PSFC consists of volunteers working together to increase the public's knowledge of fusion and plasma-related experiments. Seeking to generate excitement about science, engineering and mathematics, the PSFC holds a number of outreach activities throughout the year, such as Middle and High School Outreach Days. Outreach also includes the Mr. Magnet Program, which uses an interactive strategy to engage elementary school children. Included in this year's presentation will be a live demo of a compressed-air bottle rocket (really a one-liter plastic soda bottle) for use in high school science classrooms that researchers at the Cambridge Physics Outlet (a PSFC spin-off company) have developed. To prepare the rocket for launch, the bottle is filled with compressed air at pressures up to 80 psi and the end is plugged. The rocket is released when the plug is pulled. The gas escapes at supersonic velocities and accelerates the bottle at over 1000 m/s^2. The velocity of the bottle is measured at many locations along its ``trajectory". A simple thermodynamic model predicts performance in excellent agreement with observation. The PSFC maintains a Home Page on the World Wide Web, which can be reached at http://pfc.mit.edu.

  7. PROPOSAL FOR A CAVITY POLARIMETER AT MIT-BATES.

    SciTech Connect

    CAMERON,P.; BARRY,W.; CONTE,M.; GOLDBERG,D.A.; JACOBS,K.; LUCCIO,A.; PALAZZI,M.; PUSTERLA,M.; MACKAY,W.

    2001-06-18

    The possibility of successfully implementing a cavity polarimeter[1] has been greatly improved by the discovery[2] of a cavity mode for which the magnitude of the Stern-Gerlach force experienced by a magnetic moment traversing the cavity varies as the square of the relativistic factor gamma, so that the signal power varies as the fourth power of gamma. In addition, the interaction of this cavity mode with the beam charge varies as the inverse of the interaction with the magnetic moment, so that the background due to the beam charge varies as the inverse fourth power of gamma, If these gamma dependencies of moment and charge interaction with the pickup cavity do in fact exists the possibility is opened for very fast, accurate, and inexpensive polarimetry at accelerators like MIT-Bates and RHIC. In addition, it might become possible to seriously consider Stern-Gerlach polarization of beams at LHC. We present details of a quick polarimeter test at the electron storage ring at MIT-Bates, and of an extension of this test to a working polarimeter in the RHIC rings.

  8. Material Identification Technology (MIT) concept technical feasibility study

    SciTech Connect

    Jones, J.L.; Harker, Y.D.; Yoon, W.Y.; Johnson, L.O.

    1993-09-01

    The Idaho National Engineering Laboratory (INEL) has initiated the design and development of a novel pulsed accelerator-based, active interrogation concept. The proposed concept, referred to as the Material Identification Technology (MIT), enables rapid (between accelerator pulses), non-destructive, elemental composition analysis of both nuclear and non-nuclear materials. Applications of this technique include material monitoring in support of counter-proliferation activities, such as export controls (at domestic and international inspection locations), SNM controls, nuclear weapon dismantlement, and chemical weapon verification. Material Identification Technology combines a pulsed, X-ray source (an electron accelerator) and a gamma detection system. The accelerator must maximize neutron production (pulse width, beam current, beam energy, and repetition rate) and minimize photon dose to the object. Current available accelerator technology can meet these requirements. The detection system must include detectors which provide adequate gamma energy resolution capability, rapid recovery after the initial X-ray interrogation pulse, and multiple single gamma event detection between accelerator pulses. Further research is required to develop the detection system. This report provides the initial feasibility assessment of the MIT concept.

  9. Summary of FY 1997 related to JAPC-U.S. DOE contract study on improvement of core safety -- study on GEM (III)

    SciTech Connect

    Burke, T.M.

    1998-02-03

    FFTF was originally designed/constructed/operated to develop LMFBR fuels and materials. Inherent safety became a major focus of the US nuclear industry in the mid 1980`s. The inherent safety characteristics of LMFBRs were recognized but additional enhancement was desired. The presentation contents are: Fast Flux Test Facility history and status; Overview of contract activities; Summary of loss of flow without scram with GEMs testing; and Summary of pump start with GEMs testing.

  10. Health assessment for GEMS Landfill National Priorities List (NPL) site, Gloucester Township, Camden County, New Jersey, Region 2. CERCLIS No. NJD980529192. Final report

    SciTech Connect

    Not Available

    1989-06-05

    The GEMS Landfill is on the National Priorities List. The site covers approximately 60 acres. Contaminants at the GEMS Landfill site include volatile organic compounds, polynuclear aromatic hydrocarbons, and inorganic compounds. A monitoring program will be implemented to assess the effectiveness and reliability of remedial action. Human exposure to cadmium, lead, methylene chloride, benzene, and carcinogenic polyaromatic hydrocarbons may occur, be occurring and have occurred in the past via ingestion, inhalation, and dermal contact.

  11. CATP-6, a C. elegans Ortholog of ATP13A2 PARK9, Positively Regulates GEM-1, an SLC16A Transporter

    PubMed Central

    Lambie, Eric J.; Tieu, Pamela J.; Lebedeva, Nadja; Church, Diane L.; Conradt, Barbara

    2013-01-01

    In previous work, we found that gain-of-function mutations that hyperactivate GEM-1 (an SLC16A transporter protein) can bypass the requirement for GON-2 (a TRPM channel protein) during the initiation of gonadogenesis in C. elegans. Consequently, we proposed that GEM-1 might function as part of a Mg2+ uptake pathway that functions in parallel to GON-2. In this study, we report that CATP-6, a C. elegans ortholog of the P5B ATPase, ATP13A2 (PARK9), is necessary for gem-1 gain-of-function mutations to suppress the effects of gon-2 inactivation. One possible explanation for this observation is that GEM-1 serves to activate CATP-6, which then functions as a Mg2+ transporter. However, we found that overexpression of GEM-1 can alleviate the requirement for CATP-6 activity, suggesting that CATP-6 probably acts as a non-essential upstream positive regulator of GEM-1. Our results are consistent with the notion that P5B ATPases govern intracellular levels of Mg2+ and/or Mn2+ by regulating the trafficking of transporters and other proteins associated with the plasma membrane. PMID:24130856

  12. M.I.T. and the Federal Government. An Examination of the Effects of Government Regulation and Research Support on Selected Parts of M.I.T.

    ERIC Educational Resources Information Center

    Garvin, David

    A self-study was undertaken at the Massachusetts Institute of Technology (M.I.T.) to examine the impact of the federal government on it. M.I.T. is a large institution with an enrollment of 8,000, a faculty of 950, and a total teaching staff of 1,700. Of its operating expenses by far the largest source of funds in recent years has been sponsored…

  13. High granularity tracker based on a Triple-GEM optically read by a CMOS-based camera

    NASA Astrophysics Data System (ADS)

    Marafini, M.; Patera, V.; Pinci, D.; Sarti, A.; Sciubba, A.; Spiriti, E.

    2015-12-01

    The detection of photons produced during the avalanche development in gas chambers has been the subject of detailed studies in the past. The great progresses achieved in last years in the performance of micro-pattern gas detectors on one side and of photo-sensors on the other provide the possibility of making high granularity and very sensitive particle trackers. In this paper, the results obtained with a triple-GEM structure read-out by a CMOS based sensor are described. The use of an He/CF4 (60/40) gas mixture and a detailed optimization of the electric fields made possible to obtain a very high GEM light yield. About 80 photons per primary electron were detected by the sensor resulting in a very good capability of tracking both muons from cosmic rays and electrons from natural radioactivity.

  14. A phenomenological model to study the energy discrimination potential of GEM detectors in the X-ray range

    NASA Astrophysics Data System (ADS)

    Causa, F.; Pacella, D.; Romano, A.; Claps, G.; Gabellieri, L.

    2015-11-01

    An empirical model is presented to study the operational characteristics of GEM detectors in the X-ray range and, in particular, its energy discrimination potential. Physical processes are modelled from a macroscopic point of view, to provide a simple but effective simulation tool. Experimental data from monochromatic and combined, two-line fluorescence sources, are used to validate the model and provide realistic estimates of the empirical parameters used in the description. The model is instrumental in understanding the role of threshold, gain and operational conditions to achieve energy-discriminating response. Appropriate choices of gas mixtures, threshold and gain will permit to best utilise this new functionality of the GEM to improve the efficiency of image detectors in applications ranging from in-situ imaging in harsh environments, such as tokamaks, to composite materials analysis and medical imaging of tissues.

  15. Development of a multi-channel readout ASIC for a fast neutron spectrometer based on GEM-TPC

    NASA Astrophysics Data System (ADS)

    He, Li; Deng, Zhi; Liu, Yi-Nong; Li, Yu-Lan

    2014-10-01

    A multi-channel front-end ASIC has been developed for a fast neutron spectrometer based on Gas Electron Multiplier (GEM)-Time Projection Chamber (TPC). Charge Amplifier and Shaping Amplifier for GEM (CASAGEM) integrates 16+1 channels: 16 channels for anodes and 1 channel for cathode. The gain and the shaping time are adjustable from 2 to 40 mV/fC and from 20 to 80 ns, respectively. The prototype ASIC is fabricated in 0.35 μm CMOS process. An evaluation Print Circuit Board (PCB) was also developed for chip tests. In total 20 chips have been tested. The integrated nonlinearity is less than 1%. The equivalent noise electrons is less than 2000e when the input capacitor is 50 pF. The time jitter is less than 1 ns. The design and the test results are presented in the paper.

  16. Zenon Environmental, Inc.: ZenoGem{trademark} biological and ultrafiltration technology. Innovative technology evaluation report; Superfund innovative technology evaluation

    SciTech Connect

    1999-04-01

    Zenon Environmental Inc. (Zenon), of Burlington, Ontario, Canada had developed an innovative wastewater treatment technology called the ZenoGem{trademark} technology. The ZenoGem{trademark} technology integrates biological treatment with membrane-based ultrafiltration to treat wastewater with high concentrations of organic contaminants that cause elevated concentrations of chemical oxygen demand (COD). The Superfund Innovative Technology Evaluation (SITE) demonstration occurred between September and December 1994 at the Nascolite Superfund site (Nascolite) in Millville, Cumberland County, New Jersey. During the SITE demonstration, critical and noncritical measurements were evaluated. Critical measurements consisted of sample analyses and process measurements that directly impacted meeting the project`s primary technical objective. Critical measurements included collection of liquid and air samples for MMA and VOC analyses; liquid samples to evaluate COD; and flow rate measurements of the influent and effluent liquid streams. Noncritical, or system condition measurements, provided information on operating ranges, reliability, variability, cost-effectiveness, and full-scale remediation potential of the technology.

  17. Multifunction Instrument Tree (MIT) Neutron and Gamma Probe Acceptance for Beneficial Use (ABU)

    SciTech Connect

    CANNON, N.S.

    1999-08-08

    The multifunction instrument tree (MIT) probe program has been developed to modify existing Liquid Observation Well (LOW) neutron and gamma probes for use in the validation shafts of the two MITs installed in Tank 241-SY-101. One of the program objectives is that the modified MIT probes be completely compatible with the existing LOW van instrumentation and procedures. The major program objective is to produce neutron and gamma scans from Tank 241-SY-101 that would assist in evaluating waste feature structure and elevation. The MIT probe program is described in greater detail in the engineering task plan (HNF-3322). In accordance with the engineering task plan, a test plan (HNF-3595) was written, reduced diameter (allowing insertion into the MIT validation tube) neutron and gamma probes were acquired, an acceptance and operational test procedure (HNF-3838) was written, acceptance and operational testing of the MIT probes was performed, and a report of these test results (HNF-4369) has been issued. A number of neutron and gamma probe scans have been obtained from the Tank 241-SY-101 MITs, starting on February 8, 1999, in cooperation with Operations. Now that the MIT probes are fully demonstrated, this document transfers ownership of these probes to Operations, utilizing the final acceptance for beneficial use (ABU) form that follows in Section 3.0.

  18. Announcing the Availability of the MIT SMASS and SMASSIR Data Sets

    NASA Technical Reports Server (NTRS)

    Binzel, R. P.; Bus, S. J.; Burbine, T. H.; Rivkin, A. S.

    2001-01-01

    We announce the release of visible and near-infrared reflectance spectroscopy measurements for nearly 2000 asteroids obtained by the MIT Small Main-Belt Asteroid Spectroscopic Survey (SMASS) program. Data are being released via http://smass.mit.edu. Additional information is contained in the original extended abstract.

  19. MIT(1), a black mamba toxin with a new and highly potent activity on intestinal contraction.

    PubMed

    Schweitz, H; Pacaud, P; Diochot, S; Moinier, D; Lazdunski, M

    1999-11-19

    Mamba intestinal toxin (MIT(1)) isolated from Dendroaspis polylepis venom is a 81 amino acid polypeptide cross-linked by five disulphide bridges. MIT(1) has a very potent action on guinea-pig intestinal contractility. MIT(1) (1 nM) potently contracts longitudinal ileal muscle and distal colon, and this contraction is equivalent to that of 40 mM K(+). Conversely MIT(1) relaxes proximal colon again as potently as 40 mM K(+). The MIT(1)-induced effects are antagonised by tetrodotoxin (1 microM) in proximal and distal colon but not in longitudinal ileum. The MIT(1)-induced relaxation of the proximal colon is reversibly inhibited by the NO synthase inhibitor L-NAME (200 microM). (125)I-labelled MIT(1) binds with a very high affinity to both ileum and brain membranes (K(d)=1.3 pM and 0.9 pM, and B(max)=30 fmol/mg and 26 fmol/mg, respectively). MIT(1) is a very highly selective toxin for a receptor present both in the CNS and in the smooth muscle and which might be an as yet unidentified K(+) channel. PMID:10567694

  20. Scratch that: MIT's Mitchel Resnick Says Kids Should Do It for Themselves

    ERIC Educational Resources Information Center

    Traylor, Scott

    2008-01-01

    Mitchel Resnick is a researcher, inventor, and professor at MIT's Media Laboratory in Cambridge, MA, and the founder of the Lifelong Kindergarten Group at MIT. He is the lead innovator behind many cutting-edge learning technologies and projects for children, including the Computer Clubhouse, PicoCrickets, and the wildly successful consumer…

  1. Assessing International Product Design and Development Graduate Courses: The MIT-Portugal Program

    ERIC Educational Resources Information Center

    Dori, Yehudit Judy; Silva, Arlindo

    2010-01-01

    The Product Design and Development (PDD) course is part of the graduate curriculum in the Engineering Design and Advanced Manufacturing (EDAM) study in the MIT-Portugal Program. The research participants included about 110 students from MIT, EDAM, and two universities in Portugal, Instituto Superior Técnico-Universidade Técnica de Lisboa (IST) and…

  2. Mobile-IT Education (MIT.EDU): M-Learning Applications for Classroom Settings

    ERIC Educational Resources Information Center

    Sung, M.; Gips, J.; Eagle, N.; Madan, A.; Caneel, R.; DeVaul, R.; Bonsen, J.; Pentland, A.

    2005-01-01

    In this paper, we describe the Mobile-IT Education (MIT.EDU) system, which demonstrates the potential of using a distributed mobile device architecture for rapid prototyping of wireless mobile multi-user applications for use in classroom settings. MIT.EDU is a stable, accessible system that combines inexpensive, commodity hardware, a flexible…

  3. VizieR Online Data Catalog: Radial velocities of 1 Gem (Lane+, 2014)

    NASA Astrophysics Data System (ADS)

    Lane, B. F.; Muterspaugh, M. W.; Griffin, R. F.; Scarfe, C. D.; Fekel, F. C.; Williamson, M. H.; Eaton, J. A.; Shao, M.; Colavita, M. M.; Konacki, M.

    2016-05-01

    Extensive radial-velocity measurements of the 1 Gem system have been obtained in four separate campaigns spanning 40yr, including data from eight different instruments. Between 1969 and 2009 R.F.G. acquired a total of 128 observations of 1 Gem using the original radial-velocity spectrometer at Cambridge; a second-generation, computerized instrument at Palomar; the CORAVEL spectrometer at Haute Provence Observatory (OHP), and most recently, the Cambridge CORAVEL. The "Cambridge CORAVEL" operates at the Coude focus of the 36inch reflector on the home site of the Cambridge Observatories, Madingley Road, Cambridge, England. The Cambridge and Palomar data are referred to as data set A, while the OHP data are labeled set B. The data for components A and Ba are provided in Table1. A series of observations of 1 Gem has been obtained by C.D.S. with the Dominion Astrophysical Observatory (DAO) radial-velocity spectrometer. Observations were begun early in 1980 and continued until the end of 2003. The DAO velocities of components A and Ba are listed in Table2. The total number of acceptable velocities from DAO radial-velocity scanner observations is 123 of the primary star and 107 of the brighter component of the close pair. The third component was not detectable in the DAO traces. We identify the DAO observations as data set C. >From 1983 through 2009 F.C.F. obtained observations at the Kitt Peak National Observatory (KPNO) with the 0.9m coude feed telescope, coude spectrograph, and several different CCD detectors. All of the spectrograms were acquired with a Texas Instruments (TI) CCD except for five that were obtained in 1983 with an RCA CCD and a single observation in 2008 September with a Tektronix CCD. All those observations were centered near 6430Å and had typical signal-to-noise ratios of about 250. The numerous TI CCD spectra have a wavelength range of just 84Å and a resolution of 0.21Å. The 86 velocities of component A and 80 of component Ba are listed in Table3

  4. The occultation of Epsilon Gem by Mars as observed from Agassiz Station. [for atmosphere temperature profile investigation

    NASA Technical Reports Server (NTRS)

    Liller, W.; Papaliolios, C.; French, R. G.; Elliot, J. L.; Church, C.

    1978-01-01

    Observations of the April 8, 1976, occultation of Epsilon Gem by Mars made at the Agassiz Station of the Harvard College Observatory have been analyzed to yield temperature profiles of the Martian atmosphere for number densities between 10 to the 13th and 10 to the 15th power per cu cm. Pronounced wavelike structure is evident in both immersion and emersion profiles, with a peak-to-peak variation of up to 50 K and a vertical scale of 20 km.

  5. Searching for Binary Y dwarfs with the Gemini GeMS Multi-Conjugate Adaptive Optics System

    NASA Astrophysics Data System (ADS)

    Opitz, Daniela; Tinney, Chris

    2015-01-01

    The NASA Wide-field Infrared Survey Explorer (WISE) has delivered an exceptional harvest of new ultra-cool Y-type brown dwarfs. We present results from a diffraction-limited study of the binary status of a sample of Y dwarfs observed with the Gemini GeMS Multi-Conjugate Adaptive Optics System. We report no evidence of equal mass/luminosity binaries at separations larger than ˜ 0.5-2.0 AU for five Y dwarfs.

  6. Mild and Copper-Free Stereoselective Cyanation of gem-Difluoroalkenes by Using Benzyl Nitrile as a Cyanating Reagent.

    PubMed

    Zhang, Juan; Xu, Chengyuan; Wu, Wei; Cao, Song

    2016-07-11

    A novel copper-free highly stereoselective cyanation of gem-difluoroalkenes by using benzyl nitrile as a cyanating reagent with the assistance of tBuOLi under air atmosphere at room temperature was developed. A variety of versatile fluorinated alkenyl nitriles were obtained. The proposed mechanism involved the C-H bond oxidation, C-CN bond cleavage, and then nucleophilic vinylic substitution (SN V). PMID:27127940

  7. Temperature-driven and photo-induced MIT behaviors of VO2 nanowires

    NASA Astrophysics Data System (ADS)

    Sohn, Ahrum; Kim, Dong-Wook; Byun, Ji-Won; Baik, Jeong Min

    2014-03-01

    VO2 shows a metal-insulator transition (MIT) and structural phase transition (SPT) at critical temperature (Tc) of 343K. It has been known that the MIT and SPT behaviors of VO2 can be tuned by external stimuli such as light, electric-field, and strain. We carried out comparative studies of MIT behaviors of VO2 nanowires during heating-cooling cycles with and without illumination using several light sources (red, blue, and UV). Light can induce change in Tc and hysteresis width of the resistance change. We have investigated influences of light on SPT during MIT. In this presentation, we will discuss possible physical origins for the photo-induced effects on the MIT behaviors of the VO2 nanowires.

  8. Field test of electromagnetic induction sensor GEM300 for soil moisture retrieval

    NASA Astrophysics Data System (ADS)

    Calamita, Giuseppe; Onorati, Beniamino; Brocca, Luca; Perrone, Angela; Manfreda, Salvatore; Moramarco, Tommaso; Margiotta, Maria Rosaria; Marrese, Rosalia

    2013-04-01

    Soil moisture represents a key variable for several hydrological processes acting at hill-slope and small-catchment scale (104-107 m2). Through the classical indirect ground-based methods such as Time Domain Reflectometry (TDR) and capacitance sensors, the attention has been focusing on accuracy and precision at the small (point) scale, whereas their application over large areas has proven to be impractical and relatively expensive. In fact, considering the small sampling volume involved in the measurements, a high number of sampling sites might be required to achieve an acceptable spatial accuracy thus making the scaling-up of soil moisture measurements still problematic. Beside this, the operational difficulties that can easily arise on hard, dry or stony soils often inhibit the use of classical methods. During the last decade, a considerable interest in the hydrological community has arisen on the opportunity to move from high-precision and high-accuracy point-scale measurements to a large number of measurements over a large area with a lower precision and accuracy. In this context, geophysical methods, such as the electromagnetic induction (EMI), are potential candidate to support the study of soil moisture dynamics because of competitive costs, higher acquisition rate, easy of use, not invasive, etc. However, although the electrical resistivity is theoretically linked with soil moisture, the interpretation of electrical resistivity measurements is not straightforward, because of the influence of other soil factors. In this study, we present the preliminary results related to the comparison between a set of volumetric soil moisture measurements carried out by both portable and buried TDR probes, and the bulk soil electrical conductivity measurements collected through the GEM-300, a multi-frequency EMI sensor. The measurements were carried out in an experimental small-basin named Fiumarella di Corleto, located in Basilicata region (southern Italy). Three test

  9. Petrographic investigation of River Gem Coal, Whitley County, eastern Kentucky Coal Field

    SciTech Connect

    Pollock, J.D.; Hower, J.C.

    1987-09-01

    The River Gem coal of the Breathitt Formation (Middle Pennsylvanian) was studied at three sites in a surface mine in the Holly Hill quadrangle, Whitley County, Kentucky. The River Gem coal is correlative with the Lily and Manchester coals in neighboring Knox, Laurel, and Clay Counties, Kentucky, and the Clintwood coal in Pike County, Kentucky. At the northern site, a 14-cm rider is separated from the 92.5-cm seam by 22 cm of shale. At the two southern sites, the rider is missing. At the latter sites, the 10 cm thick top bench of the seam is separated from the lower 63 cm of the seam by a 14-cm bony lithotype not found at the northern site. The lower 63 cm of the seam in the south and the main seam in the north are characterized by moderate ash and sulfur percentages (4.4-6.8% ash, 1.4-2.3% total sulfur, 0.6-1.1% pyritic sulfur, 74-81% vitrinite, 23-32% Fe/sub 2/O/sub 3/, and 2.3-4.5% CaO). In contrast, the upper bench in the south and the rider have 18.7-27.0% ash, 8.8-11.4% total sulfur, 5.1-6.4% pyritic sulfur, 92.3-93.6% vitrinite, 45.7-57.8% Fe/sub 2/O/sub 3/ and 0.13-0.20% CaO. The bone has over 26% ash, 5.5% total sulfur, 3.2% pyritic sulfur, and 93.1% vitrinite. The overall similarity of the seam and rider characteristics between the north and south suggests that the southern bone is the lateral equivalent of the northern shale. The sulfide in the upper bench or rider and in the bone consists of fine (generally less than 10 ..mu..m), euhedral and framboidal pyrite with common massive pyrite. Massive pyrite appears as an overgrowth of fine pyrite in some places. Massive forms of marcasite, less abundant than pyrite, exhibit some evidence of developing later than the massive pyrite. A variety of < 2-..mu..m pyrite occurs as abundant, but isolated, unidimensional to tabular grains within corpocollinite, some of which is transitional to resinite.

  10. Climatology Analysis of Global Climate Models from HiGEM Family Over South America.

    NASA Astrophysics Data System (ADS)

    Custodio, M. D. S.; Ambrizzi, T.; Da Rocha, R.; Vidale, P. L.

    2014-12-01

    General Circulation Models (GCMs) have shown difficulties to correctly simulate some atmospheric patterns, especially the precipitation over South America (SA), which is often attributed to the low resolution of these models. The increased horizontal resolution of climate models aims to improve the simulations accuracy and to understand the non-linear processes during interactions between different spatial scales within the climate system. Up to this moment, these interactions did not have a good representation on low horizontal resolution GCMs. The purpose of this study was to understand the impact of the horizontal resolution in high resolution coupled and atmospheric global models of HiGEM project in simulating atmospheric patterns and processes of interaction between spatial scales. The simulations were validated using different reanalysis data and compared with observations in order to understand the impact of horizontal resolution on the precipitation systems over SA. Three different horizontal resolutions for HiGEM family models were compared ≈ 60, 90 and 135 km. Precipitation estimations from CMAP, CPC and GPCP are used for validation. Both coupled and uncoupled simulations consistently represent the observed spatial patterns related to seasonal march of the Inter-tropical Convergence Zone (ITCZ), the formation and location of the South Atlantic Convergence Zone (SACZ) and the subtropical high pressure systems in the Pacific and Atlantic Oceans. However, they overestimate the precipitation rate, especially in the ITCZ and western border regions of higher elevation, as in southern Chile. The fine horizontal resolution contributed to the large similarity between the seasonal patterns of global models and observations, with coupled models representing better these patterns than the atmospheric models in many regions of SA. The simulated annual cycles are in phase with estimations of rainfall for most of the six regions considered. An important result is that

  11. Data processing for soft X-ray diagnostics based on GEM detector measurements for fusion plasma imaging

    NASA Astrophysics Data System (ADS)

    Czarski, T.; Chernyshova, M.; Pozniak, K. T.; Kasprowicz, G.; Byszuk, A.; Juszczyk, B.; Wojenski, A.; Zabolotny, W.; Zienkiewicz, P.

    2015-12-01

    The measurement system based on GEM - Gas Electron Multiplier detector is developed for X-ray diagnostics of magnetic confinement fusion plasmas. The Triple Gas Electron Multiplier (T-GEM) is presented as soft X-ray (SXR) energy and position sensitive detector. The paper is focused on the measurement subject and describes the fundamental data processing to obtain reliable characteristics (histograms) useful for physicists. So, it is the software part of the project between the electronic hardware and physics applications. The project is original and it was developed by the paper authors. Multi-channel measurement system and essential data processing for X-ray energy and position recognition are considered. Several modes of data acquisition determined by hardware and software processing are introduced. Typical measuring issues are deliberated for the enhancement of data quality. The primary version based on 1-D GEM detector was applied for the high-resolution X-ray crystal spectrometer KX1 in the JET tokamak. The current version considers 2-D detector structures initially for the investigation purpose. Two detector structures with single-pixel sensors and multi-pixel (directional) sensors are considered for two-dimensional X-ray imaging. Fundamental output characteristics are presented for one and two dimensional detector structure. Representative results for reference source and tokamak plasma are demonstrated.

  12. The Evolutionary Behavior of Old Novae in their Quiescent Stage: DN Gem, T Aur and HR Lyr

    NASA Astrophysics Data System (ADS)

    Findlay, Amanda M.; Gropp, Jeffrey; Hause, Connor; Sion, Edward M.

    2016-01-01

    There is currently a poor understanding about how a nova explosion affects the rate of mass transfer in a cataclysmic binary system and the subsequent evolutionary behavior of the accreting white dwarf during post-nova quiescence. In order to shed light on this fundamental question, we have carried out a synthetic spectral analysis of the archival HST and IUE far ultraviolet spectra of the post-novae, DN Gem (Nova Gem 1912), T Aur (Nova Aur 1891) and HR Lyrae (Nova Lyr 1919). We have utilized the best available input parameters from the literature for the white dwarf masses, orbital inclinations and distances of each system while adopting the newly determined interstellar reddening corrections, E(B-V), of Selvelli and Gilmozzi (2013). Our synthetic spectral analysis utilized optically thick, steady state accretion disk models and white dwarf model atmospheres that we constructed using TLUSTY and SYNSPEC (Hubeny 1988, Hubeny and Lanz 1995). We report the results of our model fitting including the mass transfer rates and other physical properties 115 years (DN Gem), 124 years (T Aur) and 96 years (HR Lyra) after their respective nova explosions.This work is supported by NASA grants NNX13AF12G to Villanova University and a summerundergraduate research assistantship from the NASA-DSGC.

  13. Child Care is Everybody's Baby: A Comprehensive Report of Child Care Services, Past, Present, and Future at M.I.T. Final Child Care Proposals as Accepted by M.I.T.

    ERIC Educational Resources Information Center

    Swartz, Marilyn S.

    The report on child care services at M.I.T. explores the following areas: (1) Planning Issues: Why Should M.I.T. Be Involved in Child Care?--educational concerns, services, benefits and costs, priorities, resource allocation; (2) Background for Planning; Current Institute Child Care Programs--a concise history, M.I.T. summer day camp, the…

  14. MIT-KSC space life sciences telescience testbed

    NASA Technical Reports Server (NTRS)

    1989-01-01

    A Telescience Life Sciences Testbed is being developed. The first phase of this effort consisted of defining the experiments to be performed, investigating the various possible means of communication between KSC and MIT, and developing software and hardware support. The experiments chosen were two vestibular sled experiments: a study of ocular torsion produced by Y axis linear acceleration, based on the Spacelab D-1 072 Vestibular Experiment performed pre- and post-flight at KSC; and an optokinetic nystagmus (OKN)/linear acceleration interaction experiment. These two experiments were meant to simulate actual experiments that might be performed on the Space Station and to be representative of space life sciences experiments in general in their use of crew time and communications resources.

  15. Microfiche Image Transmission System (MITS) demonstration field evaluation of microfacsimile

    NASA Astrophysics Data System (ADS)

    Endicott, D. L., Jr.

    1983-05-01

    The MITS Demonstration was conducted for a 6-month period between 14 December 1981 and 11 June 1982. During that period, more than 1000 microfiche containing about 22,000 personnel document images were electronically transmitted between NMPC and the Personnel Support Detachment, Anacostia. These fiche represented nearly 300 active Navy personnel records. The average turnaround time was 46 minutes between making a request and receiving a facsimile record. This time included retrieval of the master microfiche, duplication, scanning, data transmission, and facsimile recording. The average scanning/transmission time was 15 minutes per record slightly less than 8 seconds per document image. The facsimile documents were found to be useful to the recipients, but improvements in both the output quality and the system itself are necessary to ensure effective implementation of an operational configuration.

  16. [R]MIT Research Centre at Delft University of Technology: A Bridge between Research, Education, Society and Profession

    ERIC Educational Resources Information Center

    Zijlstra, Hielkje

    2009-01-01

    In 2006, we launched the [R]MIT Research Centre (Modification, Intervention Transformation) at the Faculty of Architecture at Delft University of Technology. [R]MIT was founded to respond to the need for an integrated, multi-disciplinary approach to the transformation of the built environment. [R]MIT aims to bring momentum to the renewal of…

  17. Rate and Gain Limitations of MSGC's and MGC's Combined with GEM and other Preamplification Structures

    NASA Technical Reports Server (NTRS)

    Fonte, P.; Peskov, V.; Ramsey, B. D.

    1998-01-01

    We have studied the rate and gain limits of diamond-coated Microstrip Gas Counters (MSGC's) and Micro-Gap Counters (MGC's) when combined with various preamplification structures: Gas Electron Multiplier (GEM), Parallel-Plate Avalanche Chamber (PPAC) or a MICROMEGAS-type structure. Measurements were done both with X rays and alpha particles with various detector geometries and in different gas mixtures at pressures from 0.05 to 10 atm. The results obtained varied significantly with detector design, gas mixture and pressure, but some general features can be identified. We found that in all cases, bare MSGC'S, MGC'S, PPAC's and MICROMEGAS, the maximum achievable gain drops with rate. The addition of preamplification structures significantly increases the gain of MSGC's and MGC'S, but this gain is still rate dependent. There would seem to be a general rate-dependent effect governing the usable gain of all these detectors. We speculate on possible mechanisms for this effect, and identify a safe, spark-free, operation zone for each system (detector + preamplification structure) in the rate-gain coordinate plane.

  18. First Performance of the GeMS + Gmos System. Part 1. Imaging.★

    NASA Astrophysics Data System (ADS)

    Hibon, Pascale; Garrel, Vincent; Neichel, Benoit; Prout, Benjamin; Rigaut, Francois; Koning, Alice; Carrasco, Eleazar R.; Gimeno, German; Pessev, Peter

    2016-03-01

    During the commissioning of the Gemini MCAO System (GeMS), we had the opportunity to obtain data with the Gemini Multi-Object Spectrograph (GMOS), the most utilised instrument at Gemini South Observatory, in March and May 2012. Several globular clusters were observed in imaging mode that allowed us to study the performance of this new and untested combination. GMOS is a visible instrument, hence pushing MCAO toward the visible. We report here on the results with the GMOS instruments, derive photometric performance in term of Full Width Half Maximum (FWHM) and throughput. In most of the cases, we obtained an improvement factor of at least 2 against the natural seeing. This result also depends on the Natural Guide Star constellation selected for the observations and we then study the impact of the guide star selection on the FWHM performance. We also derive a first astrometric analysis showing that the GeMS+GMOS system provide an absolute astrometric precision better than 8mas and a relative astrometric precision lower than 50 mas.

  19. The Role of the GEM-Mars GCM within CROSS DRIVE

    NASA Astrophysics Data System (ADS)

    Neary, Lori; Daerden, Frank; Viscardy, Sebastien; Carine Vandaele, Ann

    2015-04-01

    CROSS DRIVE: "Collaborative Rover Operations and Planetary Science Analysis System based on Distributed Remote and Interactive Virtual Environments" The main purpose of the CROSS DRIVE FP7 project is to develop new methods and systems for collaborative scientific visualisation and data analysis, and space mission planning and operation. The developed tools and techniques will allow scientists to work together with each other's data and tools, but also to do so between missions. The project will provide technological solutions to coordinate central storage, processing and 3D visualization strategies in collaborative immersive virtual environments, to support space data analysis. A special focus is given to the preparation of the ExoMars 2016 TGO and 2018 rover missions. As a part of this project, the atmospheric model data from the GEM-Mars GCM will be utilized and integrated into the collaborative workspace to provide winds, pressure and other atmospheric properties on a global scale. The model data will be available for comparisons with the observations included in the system. We will provide a brief overview of the project and present the function of the GCM model data within it. Along with this, we will discuss recent efforts to enhance the performance of the model and the application of it to current science questions.

  20. First performance of the GeMS + GMOS system - 1. Imaging

    NASA Astrophysics Data System (ADS)

    Hibon, Pascale; Garrel, Vincent; Neichel, Benoit; Prout, Benjamin; Rigaut, Francois; Koning, Alice; Carrasco, Eleazar R.; Gimeno, German; Pessev, Peter

    2016-09-01

    During the commissioning of the Gemini MCAO System (GeMS), we had the opportunity to obtain data with the Gemini Multi-Object Spectrograph (GMOS), the most utilized instrument at Gemini South Observatory, in 2012 March and May. Several globular clusters were observed in imaging mode that allowed us to study the performance of this new and untested combination. GMOS is a visible instrument, hence pushing MCAO towards the visible. We report here on the results with the GMOS instruments, derive photometric performance in term of full width at half-maximum (FWHM) and throughput. In most of the cases, we obtained an improvement factor of at least 2 against the natural seeing. This result also depends on the natural guide star constellation selected for the observations and we then study the impact of the guide star selection on the FWHM performance. We also derive a first astrometric analysis showing that the GeMS+GMOS system provide an absolute astrometric precision better than 8 mas and a relative astrometric precision lower than 50 mas.

  1. Rings and Bent Chain Galaxies in the GEMS and GOODS Fields

    NASA Astrophysics Data System (ADS)

    Elmegreen, Debra Meloy; Elmegreen, Bruce G.

    2006-11-01

    Twenty-four galaxies with rings or partial rings were studied in the GEMS and GOODS fields out to z~1.4. Most resemble local collisional ring galaxies in morphology, size, and clumpy star formation. Clump ages range from 108 to 109 yr, and clump masses go up to several × 108 Msolar, based on color evolution models. The clump ages are consistent with the expected lifetimes of ring structures if they are formed by collisions. Fifteen other galaxies that resemble the arcs in partial ring galaxies but have no evident disk emission were also studied. Their clumps have bluer colors at all redshifts compared to the clumps in the ring and partial ring sample, and their clump ages are younger than in rings and partial rings by a factor of ~10. In most respects, they resemble chain galaxies except for their curvature; we refer to them as ``bent chains.'' Several rings are symmetric with centered nuclei and no obvious companions. They could be outer Lindblad resonance rings, although some have no obvious bars or spirals to drive them. If these symmetric cases are resonance rings, then they could be the precursors of modern resonance rings, which are only ~30% larger on average. This similarity in radius suggests that the driving pattern speed has not slowed by more by ~30% during the last ~7 Gyr. Those without bars could be examples of dissolved bars.

  2. Late Glacial vegetation reconstruction based on leaf waxes from the Gemündener Maar, Germany

    NASA Astrophysics Data System (ADS)

    Wüthrich, Lorenz; Lutz, Selina; Zech, Michael; Hepp, Johannes; Sirocko, Frank; Zech, Roland

    2015-04-01

    Lake sediments are valuable archives for the reconstruction of past changes in climate and vegetation. In the present study, we analyse samples from the Gemündener Maar, a lake situated in the western Eiffel, Germany, for their leaf wax composition: In the bottom part of the core, corresponding to the Oldest Dryas (i.e. older than ~15 ka), n-alkanes have a high average chain length (ACL), which points to a vegetation dominated by grass. During the Bölling/Alleröd, a decrease of the ACL can be interpreted as signal of more deciduous trees. During the Younger Dryas (~12.8 to 11.5 ka), the ACL increases again. Trees probably became again less abundant, before finally, the ACL records the return of deciduous trees during the early Holocene. In general, the total concentrations of both, n-alkanes and sugar biomarkers are high enough to measure compound-specific isotopes on n-alkanes (deuterium) and sugars (18-O). Combined, these two isotopes might help to obtain more information about the relative humidity and mean air temperature during the late glacial.

  3. Design of a GEM-based detector for the measurement of fast neutrons

    NASA Astrophysics Data System (ADS)

    Esposito, B.; Murtas, F.; Villari, R.; Angelone, M.; Marocco, D.; Pillon, M.; Puddu, S.

    2010-05-01

    A novel neutron detector has been developed and tested in collaboration between LNF-INFN and ENEA-Frascati. The aim is to obtain a versatile system that can be employed for the simultaneous measurement of the neutron flux in various energy bands from 1 to 20 MeV. The main drive for this development is the need of neutron detectors with low sensitivity to γ-rays and high count rate capability for operation in the neutron flux environment ~3×108 n/cm2 s expected in future controlled thermonuclear fusion reactors. In these devices the fusion power is assessed through the measurement of the 2.5 and 14 MeV neutrons emitted by the plasma. A multilayer detector architecture, including a proton recoil converter, a proton absorber and a triple Gas Electron Multiplier (GEM), has been adopted. The detector read-out system consists of 128 pads (12.3×6 mm2) in a 8×16 matrix. The work on the detector design and optimization carried out with the MCNPX code and the experimental tests at the Frascati Neutron Generator (FNG) on a detector prototype for 2.5 and 14 MeV measurements are presented.

  4. The Next Version of the Canadian Operational GEM Regional Mesoscale Model

    NASA Astrophysics Data System (ADS)

    Mailhot, J.; Belair, S.; Tremblay, A.; Lefaivre, L.; Bilodeau, B.; Glazer, A.; Patoine, A.; Talbot, D.

    2003-04-01

    A new mesoscale version of the GEM regional model in operation in Canada for numerical weather prediction has been under development for some time. The main changes to the modeling system comprise an increased resolution both in the horizontal (15 km instead of 24 km) and the vertical (43 levels instead of 28) and improvements to almost every aspects of the physics package. These include an improved formulation of the boundary layer to represent clouds with an unified moist turbulence approach, the Kain-Fritsch deep convection scheme, and the Tremblay mixed-phase condensation scheme with explicit microphysics, together with revisions to the cloud radiative optical properties. The effect of low-level blocking due to subgrid-scale orography based on the Lott-Miller scheme has also been included. The performance of the new mesoscale modeling system has been compared against the current operational model for two 6-week cycles during winter and summer 2002. Based on the North American radiosondes, significant improvements are found in the bias and RMS errors of winds and temperatures. Objective precipitation scores also show significant improvements in winter for the bias and threat scores in almost all precipitation categories, while the scores are more similar during summer.

  5. Stems to GEMs: impact of stem cell technology on engineered animal models.

    PubMed

    Halpern, Wendy; McArthur, Mark; Galbreath, Elizabeth; Uhl, Elizabeth; Buck, Wayne; Whitley, Elizabeth

    2011-09-01

    Collectively, these presentations introduced the audience to the roles of ES cells in generating phenotypes of transgenic animals,and they provided examples where the GEMs were used to define molecular mechanisms of disease or where ES cells were used as a therapeutic modality. Points of discussion among audience members reinforced the importance of strain-associated background lesions in animal models, technological advances in imaging functional biology, opportunities for stem cell therapies, and ubiquitination in regulation of cell proliferation. The 2012 American College of Veterinary Pathologists symposium ‘‘Evolutionary Aspects of Animal Models’’ will focus on the proper selection of a relevant animal model in biomedical research as critical to investigative success. Recent work characterizing rapid evolutionary changes and differences in physiology between species questions the validity of some comparative models. Dr. Robert Hamlin will be speaking on cardiovascular disease in ‘‘Animals as Models of Human Cardiovascular Disease: Or the Search to Overcome Outdated Evolutionary Homeostatic Mechanisms.’’ Dr. Stefan Niewiesk will discuss evolutionary factors that affect modeling the human immune system in ‘‘Of Mice and Men: Evolutionarily, What Are the Best Rodent Models of the Human Immune System for Infectious Disease Research?’’ Dr. Steven Austad will consider evolution in ‘‘Evolutionary Aspects of Animal Models of Aging.’’Finally, Dr. Elizabeth Uhl will conclude the session with ‘‘Modeling Disease Phenotypes: How an Evolutionary Perspective Enhances the Questions.’’ PMID:21865606

  6. Kepler Observations of V447 Lyr: an Eclipsing U Gem Cataclysmic Variable

    NASA Technical Reports Server (NTRS)

    Ramsay, Gavin; Cannizzo, John K.; Howell, Steve B.; Wood, Matt A.; Still, Martin; Barclay, Thomas; Smale, Alan

    2012-01-01

    We present the results of an analysis of Kepler data covering 1.5 yr of the dwarf nova V447 Lyr. We detect eclipses of the accretion disc by the mass donating secondary star every 3.74 h which is the binary orbital period. V447 Lyr is therefore the first dwarf nova in the Kepler field to show eclipses.We also detect five long outbursts and six short outbursts showing V447 Lyr is a U Gem-type dwarf nova. We show that the orbital phase of the mid-eclipse occurs earlier during outbursts compared to quiescence and that the width of the eclipse is greater during outburst. This suggests that the bright spot is more prominent during quiescence and that the disc is larger during outburst than quiescence. This is consistent with an expansion of the outer disc radius due to the presence of high viscosity material associated with the outburst, followed by a contraction in quiescence due to the accretion of low angular momentum material. We note that the long outbursts appear to be triggered by a short outburst, which is also observed in the super-outbursts of SU UMa dwarf novae as observed using Kepler.

  7. Vanadium-rich ruby and sapphire within Mogok Gemfield, Myanmar: implications for gem color and genesis

    NASA Astrophysics Data System (ADS)

    Zaw, Khin; Sutherland, Lin; Yui, Tzen-Fu; Meffre, Sebastien; Thu, Kyaw

    2015-01-01

    Rubies and sapphires are of both scientific and commercial interest. These gemstones are corundum colored by transition elements within the alumina crystal lattice: Cr3+ yields red in ruby and Fe2+, Fe3+, and Ti4+ ionic interactions color sapphires. A minor ion, V3+ induces slate to purple colors and color change in some sapphires, but its role in coloring rubies remains enigmatic. Trace element and oxygen isotope composition provide genetic signatures for natural corundum and assist geographic typing. Here, we show that V can dominate chromophore contents in Mogok ruby suites. This raises implications for their color quality, enhancement treatments, geographic origin, exploration and exploitation and their comparison with rubies elsewhere. Precise LA-ICP-MS analysis of ruby and sapphire from Mogok placer and in situ deposits reveal that V can exceed 5,000 ppm, giving V/Cr, V/Fe and V/Ti ratios up to 26, 78, and 97 respectively. Such values significantly exceed those found elsewhere suggesting a localized geological control on V-rich ruby distribution. Our results demonstrate that detailed geochemical studies of ruby suites reveal that V is a potential ruby tracer, encourage comparisons of V/Cr-variation between ruby suites and widen the scope for geographic typing and genesis of ruby. This will allow more precise comparison of Asian and other ruby fields and assist confirmation of Mogok sources for rubies in historical and contemporary gems and jewelry.

  8. A new front-end ASIC for GEM detectors with time and charge measurement capabilities

    NASA Astrophysics Data System (ADS)

    Ciciriello, F.; Corsi, F.; De Robertis, G.; Felici, G.; Loddo, F.; Marzocca, C.; Matarrese, G.; Ranieri, A.

    2016-07-01

    A 32 channel CMOS front-end ASIC has been designed to read out the GEM detectors intended to be used for beam monitoring in a new proton-therapy facility currently under construction. In order to improve the spatial resolution by exploiting charge centroid algorithms, the analog channels, based on the classic CSA+shaper architecture, are equipped with a peak detector (PD) which works as an analog memory during the read-out phase. The outputs of the PDs are multiplexed towards an integrated 8-bit subranging ADC. An accurate trigger signal marks the arrival of a valid event and is generated by fast-ORing the outputs of 32 voltage discriminators which compare the shaper outputs with a programmable threshold. The digital part of the ASIC manages the read-out of the channels, the A/D conversion and the configuration of the ASIC. A 100 Mbit/s LVDS serial link is used for data communication. The sensitivity of the analog channel is 15 mV/fC and the dynamic range is 80 fC. The simulated ENC is about 650 e- for a detector capacitance of 10 pF. © 2001 Elsevier Science. All rights reserved

  9. Statistics of atmospheric turbulence at Cerro Pachon using the GeMS profiler

    NASA Astrophysics Data System (ADS)

    Rodriguez, Ignacio; Neichel, Benoit; Béchet, Clémentine; Guzmán, Dani; Guesalaga, Andrés.

    2014-08-01

    The knowledge of the atmospheric turbulence profile directly above the telescope using the telemetry from wide-field Adaptive Optics (AO) measurements can be extremely useful for the optimization of the correction in the new generation of AO systems. For this purpose, two techniques have been recently implemented at the Gemini South MCAO System (GeMS); both based on the SLODAR method. The first technique uses a matrix inversion approach of the slopes covariance matrices and the second deconvolves the cross-correlation functions between all combinations of slopes using the auto-correlation responses. The deconvolution approach has proved to be more reliable that the one based on matrices inversion, so we use it for estimating the profiles from on-sky telemetry gathered over three years (2012 - 2014), obtaining statistical parameters of the turbulence at Cerro Pachón. These results are summarized in this article. Particular attention is paid to the occurrence of turbulence in the dome of the Gemini South telescope.

  10. Effects from switching on PIC simulations: Geospace Environmental Modeling (GEM) reconnection setup revisited

    NASA Astrophysics Data System (ADS)

    Bourdin, P. A.; Nakamura, T.; Narita, Y.

    2015-12-01

    Electromagnetic Parcile-In-Cell (PIC) simulations are widely used to study plasma phenomena where kinetic scales are coupled to fluid scales. One of these phenomena is the evolution of magnetic reconnection. Switch-on effects have been described earlier for magneto-/hydrodynamic (MHD and HD) simulations, where oscillations are ignited by the initial condition and the usual instantaneous way of starting a simulation run. Here we revisit the GEM setup (a Harris current sheet) and demonstrate the immediate generation of oscillations propagating perpendicular to the magnetic shear layer (in Bz). Also we show how these oscillations do not dissipate quickly and will later be mode-converted to generate wave power, first in By, much later also in Bx (pointing along the shear direction). One needs to take care not to interpret these oscillations as physical wave modes associated with the nature of reconnection. We propose a method to prevent such switch-on effects from the beginning, that should be considered for implementation in other PIC simulation codes as well.

  11. Anti-Oncogenic gem-Dihydroperoxides Induce Apoptosis in Cancer Cells by Trapping Reactive Oxygen Species

    PubMed Central

    Kuranaga, Yuki; Yamada, Nami; Kashiwaya, Maiko; Nakamura, Moeko; Cui, Lei; Kumazaki, Minami; Shinohara, Haruka; Sugito, Nobuhiko; Taniguchi, Kohei; Ito, Yuko; Nakayama, Tatsushi; Uno, Bunji; Itoh, Akichika; Akao, Yukihiro

    2016-01-01

    Organic gem-dihydroperoxides (DHPs) and their derived peroxides have attracted a great deal of attention as potential anti-cancer agents. However, the precise mechanism of their inhibitory effect on tumors is unknown. To determine the mechanism of the inhibitory effects of DHPs, we examined the effects of DHPs on leukemia K562 cells. As a result, certain DHPs used in this study exhibited growth-inhibitory activity according to a clear structure-activity relationship. The most potent DHP, 12AC3O, induced apoptosis in K562 cells, but not in peripheral blood monocytes (PBMCs) or fibroblast cells. 12AC3O induced apoptosis through the intrinsic mitochondrial pathway and thereafter through the extrinsic pathway. The activity of the former pathway was partly attenuated by a JNK inhibitor. Interestingly, 12AC3O induced apoptosis by trapping a large amount of ROS, leading to an extremely lower intracellular ROS level compared with that in the cells in the steady-state condition. These results suggest that an appropriate level of intracellular ROS was necessary for the maintenance of cancer cell growth. DHPs may have a potential to be a novel anti-cancer agent with minimum adverse effects on normal cells. PMID:26760996

  12. Mars methane emission and transport scenarios using the GEM-Mars GCM

    NASA Astrophysics Data System (ADS)

    Neary, Lori; Daerden, Frank; Kaminski, J. W.; McConnell, J. C.

    2010-05-01

    The observation of methane (Formisano et al., 2004; Krasnopolsky et al., 2004; Mumma et al., 2009) in the Martian atmosphere has raised questions about its source and origin as well as its chemical behaviour. The photochemical lifetime of methane is on the order of several hundred years which would give a well-mixed, uniform distribution but measurements suggest locally enhanced "plumes". The GEM-Mars three-dimensional global chemistry-climate model is used to investigate the possible emission rates and lifetime of methane. The model simulations have a horizontal resolution of 4x4 degrees with 101 vertical levels up to approximately 140 km. References Formisano, V., S. Atreya, T. Encrenaz, N. Ignatiev, and M. Giuranna (2004), Detection of Methane in the Atmosphere of Mars, Science 306, 1758 (2004). Krasnopolsky, V. A., J. P. Maillard, and T. C. Owen (2004), Icarus 172, 537. Mumma, M.J., G.L. Villanueva, R.E. Novak, T. Hewagama, B.P. Bonev, M.A. DiSanti, A.M. Mandell, and M.D. Smith (2009), Strong Release of Methane on Mars in Northern Summer 2003. Science, 2009. 323: p. 1041-1045.

  13. Multichannel reconfigurable measurement system for hot plasma diagnostics based on GEM-2D detector

    NASA Astrophysics Data System (ADS)

    Wojenski, A. J.; Kasprowicz, G.; Pozniak, K. T.; Byszuk, A.; Chernyshova, M.; Czarski, T.; Jablonski, S.; Juszczyk, B.; Zienkiewicz, P.

    2015-12-01

    In the future magnetically confined fusion research reactors (e.g. ITER tokamak), precise determination of the level of the soft X-ray radiation of plasma with temperature above 30 keV (around 350 mln K) will be very important in plasma parameters optimization. This paper presents the first version of a designed spectrography measurement system. The system is already installed at JET tokamak. Based on the experience gained from the project, the new generation of hardware for spectrography measurements, was designed and also described in the paper. The GEM detector readout structure was changed to 2D in order to perform measurements of i.e. laser generated plasma. The hardware structure of the system was redesigned in order to provide large number of high speed input channels. Finally, this paper also covers the issue of new control software, necessary to set-up a complete system of certain complexity and perform data acquisition. The main goal of the project was to develop a new version of the system, which includes upgraded structure and data transmission infrastructure (i.e. handling large number of measurement channels, high sampling rate).

  14. Diagnostic Microbiologic Methods in the GEMS-1 Case/Control Study

    PubMed Central

    Panchalingam, Sandra; Antonio, Martin; Hossain, Anowar; Mandomando, Inacio; Ochieng, Ben; Oundo, Joseph; Ramamurthy, T.; Tamboura, Boubou; Zaidi, Anita K. M.; Petri, William; Houpt, Eric; Murray, Patrick; Prado, Valeria; Vidal, Roberto; Steele, Duncan; Strockbine, Nancy; Sansonetti, Philippe; Glass, Roger I.; Robins-Browne, Roy M.; Tauschek, Marija; Svennerholm, Ann-Marie; Kotloff, Karen; Levine, Myron M.; Nataro, James P.

    2012-01-01

    To understand the etiology of moderate-to-severe diarrhea among children in high mortality areas of sub-Saharan Africa and South Asia, we performed a comprehensive case/control study of children aged <5 years at 7 sites. Each site employed an identical case/control study design and each utilized a uniform comprehensive set of microbiological assays to identify the likely bacterial, viral and protozoal etiologies. The selected assays effected a balanced consideration of cost, robustness and performance, and all assays were performed at the study sites. Identification of bacterial pathogens employed streamlined conventional bacteriologic biochemical and serological algorithms. Diarrheagenic Escherichia coli were identified by application of a multiplex polymerase chain reaction assay for enterotoxigenic, enteroaggregative, and enteropathogenic E. coli. Rotavirus, adenovirus, Entamoeba histolytica, Giardia enterica, and Cryptosporidium species were detected by commercially available enzyme immunoassays on stool samples. Samples positive for adenovirus were further evaluated for adenovirus serotypes 40 and 41. We developed a novel multiplex assay to detect norovirus (types 1 and 2), astrovirus, and sapovirus. The portfolio of diagnostic assays used in the GEMS study can be broadly applied in developing countries seeking robust cost-effective methods for enteric pathogen detection. PMID:23169941

  15. The ISC-GEM Global Instrumental Earthquake Catalogue (1900-2009): Introduction

    NASA Astrophysics Data System (ADS)

    Storchak, D. A.; Di Giacomo, D.; Engdahl, E. R.; Harris, J.; Bondár, I.; Lee, W. H. K.; Bormann, P.; Villaseñor, A.

    2015-02-01

    In this introductory article we give a general description of the ISC-GEM Global Instrumental Earthquake Catalogue (1900-2009). We also provide the background for four further articles that describe the effort in collecting and digitizing parametric earthquake bulletin data as well as the methodologies developed to compute homogeneous earthquake parameters. The result of the two and a half year project is a catalogue of approximately 20,000 large earthquakes covering 110 years with hypocentres and uncertainties computed using the same technique and velocity model. We show that the overall homogeneity of the main earthquake parameters in the catalogue was achieved despite changes in instrumentation and routine measurement practices concurrent with developments in instrumental seismology from almost a ground level to its current state. For each earthquake, MW magnitude values and uncertainties were computed either based on available estimates of seismic moment or using new empirical relationships between MW, MS and mb. Further important results of this project include the electronic availability of a considerable volume of seismic wave arrival time and amplitude measurements from early instrumental printed station bulletins. These newly recovered amplitude measurements provided a basis for computation of many previously unavailable MS magnitudes with uncertainties. In this article we describe why such a catalogue is required for a comprehensive assessment of global and regional seismic hazard. We also describe other potential uses of the catalogue in many other fields of Earth Sciences. We discuss the catalogue availability and lay out the plans of further development.

  16. GEM-CEDAR Study of Ionospheric Energy Input and Joule Dissipation

    NASA Technical Reports Server (NTRS)

    Rastaetter, Lutz; Kuznetsova, Maria M.; Shim, Jasoon

    2012-01-01

    We are studying ionospheric model performance for six events selected for the GEM-CEDAR modeling challenge. DMSP measurements of electric and magnetic fields are converted into Poynting Flux values that estimate the energy input into the ionosphere. Models generate rates of ionospheric Joule dissipation that are compared to the energy influx. Models include the ionosphere models CTIPe and Weimer and the ionospheric electrodynamic outputs of global magnetosphere models SWMF, LFM, and OpenGGCM. This study evaluates the model performance in terms of overall balance between energy influx and dissipation and tests the assumption that Joule dissipation occurs locally where electromagnetic energy flux enters the ionosphere. We present results in terms of skill scores now commonly used in metrics and validation studies and we can measure the agreement in terms of temporal and spatial distribution of dissipation (i.e, location of auroral activity) along passes of the DMSP satellite with the passes' proximity to the magnetic pole and solar wind activity level.

  17. Performance of a large-area GEM detector read out with wide radial zigzag strips

    NASA Astrophysics Data System (ADS)

    Zhang, Aiwu; Bhopatkar, Vallary; Hansen, Eric; Hohlmann, Marcus; Khanal, Shreeya; Phipps, Michael; Starling, Elizabeth; Twigger, Jessie; Walton, Kimberly

    2016-03-01

    A 1-meter-long trapezoidal Triple-GEM detector with wide readout strips was tested in hadron beams at the Fermilab Test Beam Facility in October 2013. The readout strips have a special zigzag geometry and run radially with an azimuthal pitch of 1.37 mrad to measure the azimuthal ϕ-coordinate of incident particles. The zigzag geometry of the readout reduces the required number of electronic channels by a factor of three compared to conventional straight readout strips while preserving good angular resolution. The average crosstalk between zigzag strips is measured to be an acceptable 5.5%. The detection efficiency of the detector is (98.4±0.2)%. When the non-linearity of the zigzag-strip response is corrected with track information, the angular resolution is measured to be (193±3) μrad, which corresponds to 14% of the angular strip pitch. Multiple Coulomb scattering effects are fully taken into account in the data analysis with the help of a stand-alone Geant4 simulation that estimates interpolated track errors.

  18. THE PHASES DIFFERENTIAL ASTROMETRY DATA ARCHIVE. IV. THE TRIPLE STAR SYSTEMS 63 Gem A AND HR 2896

    SciTech Connect

    Muterspaugh, Matthew W.; Fekel, Francis C.; Williamson, M.; Lane, Benjamin F.; Hartkopf, William I.; Kulkarni, S. R.; Konacki, Maciej; Burke, Bernard F.; Colavita, M. M.; Shao, M. E-mail: blane@draper.co E-mail: maciej@ncac.torun.p

    2010-12-15

    Differential astrometry measurements from the Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) are used to constrain the astrometric orbit of the previously known {approx}<2 day subsystem in the triple system 63 Gem A and have detected a previously unknown two-year Keplerian wobble superimposed on the visual orbit of the much longer period (213 years) binary system HR 2896. 63 Gem A was already known to be triple from spectroscopic work, and absorption lines from all three stars can be identified and their individual Doppler shifts measured; new velocities for all three components are presented to aid in constraining the orbit and measuring the stellar masses. In fact, 63 Gem itself is a sextuple system: the hierarchical triple (Aa1-Aa2)-Ab (in which Aa1 and Aa2 orbit each other with a rapid period just under 2 days, and Ab orbits these every two years), plus three distant common proper motion companions. The very small astrometric perturbation caused by the inner pair in 63 Gem A stretches the limits of current astrometric capabilities, but PHASES observations are able to constrain the orientation of the orbit. The two bright stars comprising the HR 2896 long-period (213 year) system have a combined spectral type of K0III and the newly detected object's mass estimate places it in the regime of being an M dwarf. The motion of the stars are slow enough that their spectral features are always blended, preventing Doppler studies. The PHASES measurements and radial velocities (when available) have been combined with lower precision single-aperture measurements covering a much longer time frame (from eyepiece measurements, speckle interferometry, and adaptive optics) to improve the characterization of the long-period orbits in both binaries. The visual orbits of the short- and long-period systems are presented for both systems and used to calculate two possible values of the mutual inclinations between inner and outer orbits of 152{sup 0} {+-} 12

  19. Investigation of the "Escalator Effect" in the Kilmore East Fire of February, 2009 using GEM-AQ

    NASA Astrophysics Data System (ADS)

    Beale, J. L.; Semeniuk, K.; Lupu, A.; Kaminski, J. W.; McConnell, J. C.; O'Neill, N. T.; Glatthor, N.; Höpfner, M.; Palmer, P. I.; Tost, H.

    2012-12-01

    In early February, 2009, Southeast Australia was swept by intense bush fires which burned an area of about 3000 km2. Combustion products such as C2H2, HCN and HCOOH were observed in the UTLS region a few days later by MIPAS on the ENVISAT satellite. In addition, the OSIRIS instrument on the ODIN spacecraft has attributed aerosol measurements to products of the burning and lifting while the MLS instrument on AURA measured high values of CO for several weeks after the fire. This study is a continuation of the study by Glatthor et al (2012) which compared MIPAS observations to a high-resolution model run of the Global Environmental Multiscale with Air Quality (GEM-AQ) model. There is generally good agreement between the modelling and the observations, but there is still uncertainty as to whether the lifting of material into the UTLS by the fire process can be considered pyroconvection, or if it is due to the diabatic heating and lifting of the aerosol produced in the burning process (the "escalator effect"), or both. One limitation of our earlier study was the injection process of burning species and the lack of radiatively and chemically active aerosols within GEM-AQ. In this study we add black carbon (BC) and organic carbon (OC) estimates as part of the burning process and assess their role in the lifting of the biomass-burning material. The work described here uses GEM version 3.3.2. The gas-phase chemistry consists of detailed reactions of Ox, NOx, HOx, CO, CH4, NMVOCs, halocarbons, ClOx and BrO. We have recently added elements of the Global Modal-aerosol eXtension (GMXe) scheme to address aerosol microphysics and gas-aerosol partitioning. GEM-AQ is a global general circulation model based on the GEM model developed by the Meteorological Service of Canada for operational weather forecasting with on-line air quality and chemistry. It can be run with a global variable (GV) grid where the core has uniform grid spacing and the exterior grid expands. Our simulations

  20. 2mit, an Intronic Gene of Drosophila melanogaster timeless2, Is Involved in Behavioral Plasticity

    PubMed Central

    Benna, Clara; Leonardi, Emanuela; Romoli, Ottavia; Cognolato, Moira; Tosatto, Silvio C. E.; Costa, Rodolfo; Sandrelli, Federica

    2013-01-01

    Background Intronic genes represent ~6% of the total gene complement in Drosophila melanogaster and ~85% of them encode for proteins. We recently characterized the D. melanogaster timeless2 (tim2) gene, showing its active involvement in chromosomal stability and light synchronization of the adult circadian clock. The protein coding gene named 2mit maps on the 11th tim2 intron in the opposite transcriptional orientation. Methodology/Principal Findings Here we report the molecular and functional characterization of 2mit. The 2mit gene is expressed throughout Drosophila development, localizing mainly in the nervous system during embryogenesis and mostly in the mushroom bodies and ellipsoid body of the central complex in the adult brain. In silico analyses revealed that 2mit encodes a putative leucine-Rich Repeat transmembrane receptor with intrinsically disordered regions, harboring several fully conserved functional interaction motifs in the cytosolic side. Using insertional mutations, tissue-specific over-expression, and down-regulation approaches, it was found that 2mit is implicated in adult short-term memory, assessed by a courtship conditioning assay. In D. melanogaster, tim2 and 2mit do not seem to be functionally related. Bioinformatic analyses identified 2MIT orthologs in 21 Drosophilidae, 4 Lepidoptera and in Apis mellifera. In addition, the tim2-2mit host-nested gene organization was shown to be present in A. mellifera and maintained among Drosophila species. Within the Drosophilidae 2mit-hosting tim2 intron, in silico approaches detected a neuronal specific transcriptional binding site which might have contributed to preserve the specific host-nested gene association across Drosophila species. Conclusions/Significance Taken together, these results indicate that 2mit, a gene mainly expressed in the nervous system, has a role in the behavioral plasticity of the adult Drosophila. The presence of a putative 2mit regulatory enhancer within the 2mit-hosting tim2

  1. GEM-loaded magnetic albumin nanospheres modified with cetuximab for simultaneous targeting, magnetic resonance imaging, and double-targeted thermochemotherapy of pancreatic cancer cells

    PubMed Central

    Wang, Ling; An, Yanli; Yuan, Chenyan; Zhang, Hao; Liang, Chen; Ding, Fengan; Gao, Qi; Zhang, Dongsheng

    2015-01-01

    Background Targeted delivery is a promising strategy to improve the diagnostic imaging and therapeutic effect of cancers. In this paper, novel cetuximab (C225)-conjugated, gemcitabine (GEM)-containing magnetic albumin nanospheres (C225-GEM/MANs) were fabricated and applied as a theranostic nanocarrier to conduct simultaneous targeting, magnetic resonance imaging (MRI), and double-targeted thermochemotherapy against pancreatic cancer cells. Methods Fe3O4 nanoparticles (NPs) and GEM co-loaded albumin nanospheres (GEM/MANs) were prepared, and then C225 was further conjugated to synthesize C225-GEM/MANs. Their morphology, mean particle size, GEM encapsulation ratio, specific cell-binding ability, and thermal dynamic profiles were characterized. The effects of discriminating different EGFR-expressing pancreatic cancer cells (AsPC-1 and MIA PaCa-2) and monitoring cellular targeting effects were assessed by targeted MRI. Lastly, the antitumor efficiency of double/C225/magnetic-targeted and nontargeted thermochemotherapy was compared with chemotherapy alone using 3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and flow cytometry (FCM) assay. Results When treated with targeted nanospheres, AsPC-1 cells showed a significantly less intense MRI T2 signal than MIA PaCa-2 cells, while both cells had similar signal strength when incubated with nontargeted nanospheres. T2 signal intensity was significantly lower when magnetic and C225 targeting were combined, rather than used alone. The inhibitory and apoptotic rates of each thermochemotherapy group were significantly higher than those of the chemotherapy-alone groups. Additionally, both MTT and FCM analysis verified that double-targeted thermochemotherapy had the highest targeted killing efficiency among all groups. Conclusion The C225-GEM/MANs can distinguish various EGFR-expressing live pancreatic cancer cells, monitor diverse cellular targeting effects using targeted MRI imaging, and efficiently mediate

  2. The structure of the GemC1 coiled coil and its interaction with the Geminin family of coiled-coil proteins

    SciTech Connect

    Caillat, Christophe; Fish, Alexander; Pefani, Dafni-Eleftheria; Taraviras, Stavros; Lygerou, Zoi; Perrakis, Anastassis

    2015-10-31

    The GemC1 coiled-coil structure has subtle differences compared with its homologues Geminin and Idas. Co-expression experiments in cells and biophysical stability analysis of the Geminin-family coiled coils suggest that the GemC1 coiled coil alone is unstable. GemC1, together with Idas and Geminin, an important regulator of DNA-replication licensing and differentiation decisions, constitute a superfamily sharing a homologous central coiled-coil domain. To better understand this family of proteins, the crystal structure of a GemC1 coiled-coil domain variant engineered for better solubility was determined to 2.2 Å resolution. GemC1 shows a less typical coiled coil compared with the Geminin homodimer and the Geminin–Idas heterodimer structures. It is also shown that both in vitro and in cells GemC1 interacts with Geminin through its coiled-coil domain, forming a heterodimer that is more stable that the GemC1 homodimer. Comparative analysis of the thermal stability of all of the possible superfamily complexes, using circular dichroism to follow the unfolding of the entire helix of the coiled coil, or intrinsic tryptophan fluorescence of a unique conserved N-terminal tryptophan, shows that the unfolding of the coiled coil is likely to take place from the C-terminus towards the N-terminus. It is also shown that homodimers show a single-state unfolding, while heterodimers show a two-state unfolding, suggesting that the dimer first falls apart and the helices then unfold according to the stability of each protein. The findings argue that Geminin-family members form homodimers and heterodimers between them, and this ability is likely to be important for modulating their function in cycling and differentiating cells.

  3. Star in Deep Freeze Chills Theory, MIT Researchers Report

    NASA Astrophysics Data System (ADS)

    2001-09-01

    CAMBRIDGE, Mass. -- Like a frozen turkey that just won't thaw, a strange star near the center of the Milky Way is surprising MIT experts and colleagues with its remarkably low temperature. The odd behavior is chilling current theories of stellar physics. A famously battered neutron star named KS 1731-260 appears no hotter than some of its tranquil brethren, despite enduring the heat of constant thermonuclear explosions with the force of billions of hydrogen bombs every second across a region only a few miles wide for the past 12 years. Dr. Rudi Wijnands, an astrophysicist at MIT's Center for Space Research, used the Chandra X-ray Observatory to measure the temperature of the neutron star at a very opportune moment, only months after the nuclear war apparently ended and the smoke cleared. He presented his team's findings September 5 in Washington, D.C. at a scientific conference entitled "Two Years of Science with Chandra." "Twelve years of constant thermonuclear explosions: One would think that would heat things up," said Wijnands. "This leaves us wondering whether some neutron stars are in the freezer for a much longer time than previously thought and consequently take a long time to heat up, or whether they cool down incredibly fast. Either explanation has profound implications for our field." Neutron stars are the dense, core remains of stars once many times more massive than our Sun. They are created in dazzling supernovas, in which the outer shell of the star explodes into space, and the core, containing about as much mass as the Sun, implodes and collapses into a sphere no wider than Cambridge, Massachusetts. Despite their tiny size, neutron stars are visible in several ways. One is through accretion. Neutron stars are a strong source of gravity. When they exist in binary star systems, such as KS 1731-260, they can attract the gas from what is often a "healthy" hydrogen-burning companion star (although the nature of KS 1731-260's companion is not clear.) Gas

  4. Having Fun with Physics at the MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Rivenberg, P.; Thomas, P.; Censabella, V.; Granville, J.; Nachtrieb, R.; Gangadhara, S.

    1997-11-01

    MIT Plasma Science and Fusion Center staff and students are convinced that students learn best not by studying but by doing. This was the impetus behind a group of MIT graduate students who created Cambridge Physics Outlet, a PSFC spin-off company dedicated to creating hands-on experiments. The same impulse fostered the award-winning Mr. Magnet Program, a traveling presentation which uses a hands-on strategy to engage elementary school children. A number of ingenious experiments will be demonstrated. The PSFC maintains a Home Page on the World Wide Web, which can be reached at HTTP://PFC.MIT.EDU.

  5. C-GEM (v 1.0): a new, cost-efficient biogeochemical model for estuaries and its application to a funnel-shaped system

    NASA Astrophysics Data System (ADS)

    Volta, C.; Arndt, S.; Savenije, H. H. G.; Laruelle, G. G.; Regnier, P.

    2013-11-01

    The first part of this paper describes C-GEM (Carbon - Generic Estuary Model), a new, one-dimensional, generic reactive-transport model for the biogeochemical dynamics of carbon and associated bio-elements (N, P, Si) in estuaries. C-GEM is computationally efficient and reduces data-requirements by using an idealized representation of the estuarine geometry to quantitatively predict the dominant features of the estuarine hydrodynamics, salt transport and biogeochemistry. A protocol for the set-up of C-GEM for an estuarine system is also described. The second part of this paper presents, as a proof of concept, the application of C-GEM to the funnel-shaped Scheldt estuary (Belgium, the Netherlands), one of the best-surveyed system in the world. Steady-state and transient simulations are performed and the performance of C-GEM is evaluated through model-data and model-model comparison, using integrated measures of the estuarine biogeochemical functioning, such as system-wide estimates of the Net Ecosystem Metabolism (NEM). A sensitivity analysis is also carried out to identify model parameters that exert the most important control on biogeochemical processes and to assess the sensitivity of the NEM to uncertainties in parameter values. The paper ends by a short discussion of current model limitations with respect to local, regional and global scale applications.

  6. Development of a scintillating G-GEM detector for a 6-MeV X-band Linac for medical applications

    NASA Astrophysics Data System (ADS)

    Fujiwara, T.; Tanaka, S.; Mitsuya, Y.; Takahashi, H.; Tagi, K.; Kusano, J.; Tanabe, E.; Yamamoto, M.; Nakamura, N.; Dobashi, K.; Tomita, H.; Uesaka, M.

    2013-12-01

    We recently developed glass gas electron multipliers (G-GEMs) with an entirely new process using photo-etchable glass. The photo-etchable glass used for the substrate is called PEG3 (Hoya Corporation). Taking advantage of low outgassing material, we have envisioned a medical application of G-GEMs. A two-dimensional position-sensitive dosimetry system based on a scintillating gas detector is being developed for real-time dose distribution monitoring in X-ray radiation therapy. The dosimetry system consists of a chamber filled with an Ar/CF4 scintillating gas mixture, inside of which G-GEM structures are mounted. Photons produced by the excited Ar/CF4 gas molecules during the gas multiplication in the GEM holes are detected by a mirror-lens-CCD-camera system. We found that the intensity distribution of the measured light spot is proportional to the 2D dose distribution. In this work, we report on the first results from a scintillating G-GEM detector for a position-sensitive X-ray beam dosimeter.

  7. Solution of the inverse problem of magnetic induction tomography (MIT).

    PubMed

    Merwa, Robert; Hollaus, Karl; Brunner, Patricia; Scharfetter, Hermann

    2005-04-01

    Magnetic induction tomography (MIT) of biological tissue is used to reconstruct the changes in the complex conductivity distribution inside an object under investigation. The measurement principle is based on determining the perturbation DeltaB of a primary alternating magnetic field B0, which is coupled from an array of excitation coils to the object under investigation. The corresponding voltages DeltaV and V0 induced in a receiver coil carry the information about the passive electrical properties (i.e. conductivity, permittivity and permeability). The reconstruction of the conductivity distribution requires the solution of a 3D inverse eddy current problem. As in EIT the inverse problem is ill-posed and on this account some regularization scheme has to be applied. We developed an inverse solver based on the Gauss-Newton-one-step method for differential imaging, and we implemented and tested four different regularization schemes: the first and second approaches employ a classical smoothness criterion using the unit matrix and a differential matrix of first order as the regularization matrix. The third method is based on variance uniformization, and the fourth method is based on the truncated singular value decomposition. Reconstructions were carried out with synthetic measurement data generated with a spherical perturbation at different locations within a conducting cylinder. Data were generated on a different mesh and 1% random noise was added. The model contained 16 excitation coils and 32 receiver coils which could be combined pairwise to give 16 planar gradiometers. With 32 receiver coils all regularization methods yield fairly good 3D-images of the modelled changes of the conductivity distribution, and prove the feasibility of difference imaging with MIT. The reconstructed perturbations appear at the right location, and their size is in the expected range. With 16 planar gradiometers an additional spurious feature appears mirrored with respect to the median

  8. Development of 2D imaging of SXR plasma radiation by means of GEM detectors

    NASA Astrophysics Data System (ADS)

    Chernyshova, M.; Czarski, T.; Jabłoński, S.; Kowalska-Strzeciwilk, E.; Poźniak, K.; Kasprowicz, G.; Zabołotny, W.; Wojeński, A.; Byszuk, A.; Burza, M.; Juszczyk, B.; Zienkiewicz, P.

    2014-11-01

    Presented 2D gaseous detector system has been developed and designed to provide energy resolved fast dynamic plasma radiation imaging in the soft X-Ray region with 0.1 kHz exposure frequency for online, made in real time, data acquisition (DAQ) mode. The detection structure is based on triple Gas Electron Multiplier (GEM) amplification structure followed by the pixel readout electrode. The efficiency of detecting unit was adjusted for the radiation energy region of tungsten in high-temperature plasma, the main candidate for the plasma facing material for future thermonuclear reactors. Here we present preliminary laboratory results and detector parameters obtained for the developed system. The operational characteristics and conditions of the detector were designed to work in the X-Ray range of 2-17 keV. The detector linearity was checked using the fluorescence lines of different elements and was found to be sufficient for good photon energy reconstruction. Images of two sources through various screens were performed with an X-Ray laboratory source and 55Fe source showing a good imaging capability. Finally offline stream-handling data acquisition mode has been developed for the detecting system with timing down to the ADC sampling frequency rate (~13 ns), up to 2.5 MHz of exposure frequency, which could pave the way to invaluable physics information about plasma dynamics due to very good time resolving ability. Here we present results of studied spatial resolution and imaging properties of the detector for conditions of laboratory moderate counting rates and high gain.

  9. Geochemical and palynological indicators of the paleoecology of the River Gem coal bed, Whitley County, Kentucky

    USGS Publications Warehouse

    Hower, J.C.; Ruppert, L.F.; Eble, C.F.; Graham, U.M.

    1996-01-01

    The River Gem coal bed (upper Westphalian A) was sampled at five sites in a single mine in Whitley County, Kentucky. Previous petrographic and sulfur analyses of the collected interval samples showed that the coal bed could be divided into a basal low-sulfur lithotype, a middle high-sulfur bone lithotype and an upper high-sulfur lithotype. At one location a high-sulfur rider unit is present. In this study we have conducted detailed palynological analyses on all of the interval samples and ash geochemistry on the upper high-sulfur lithotype intervals and two of the basal high-sulfur basal lithotype intervals. Geochemical analyses show that As and Pb are generally high in the high-sulfur upper lithotypes from all five sites. Carbonates, having associated high levels of Ba and Sr, are important in the ash geochemistry of the lower, low-sulfur lithotypes. Ga, Ge and W are enriched in the higher vitrinite lithotypes among the low-sulfur samples. The basal lithotype at each of two sites, which was analyzed in detail, is enriched in yttrium plus the lighter rare earth elements. The basal low-sulfur lithotypes are dominated by arboreous lycopod spores. The middle, low-sulfur portion of the bed is dominated by herbaceous lycopsids (Densosporites) at the base of the unit and becomes increasingly enriched in Lycospora towards the top of the unit indicating that the peat-forming environment became wetter. The greatest arboreous lycopod spore abundances in the upper, high-sulfur portion the bed, along with an overlying marine roof, indicates that peat deposition was terminated by a marine inundation.

  10. GeMS MCAO observations of the Galactic globular cluster NGC 2808: the absolute age

    NASA Astrophysics Data System (ADS)

    Massari, D.; Fiorentino, G.; McConnachie, A.; Bono, G.; Dall'Ora, M.; Ferraro, I.; Iannicola, G.; Stetson, P. B.; Turri, P.; Tolstoy, E.

    2016-02-01

    Context. Globular clusters are the oldest stellar systems in the Milky Way, and they probe the early epoch of the Galaxy formation. However, the uncertainties on their absolute age are still too large to soundly constrain how the Galactic structures have assembled. Aims: The aim of this work is to obtain an accurate estimate of the absolute age of the globular cluster NGC 2808 using deep IR data obtained with the multi-conjugate adaptive optics system operating at the Gemini South telescope (GeMS). Methods: This exquisite photometry, combined with that obtained in V and I-bands with HST, allowed us to detect the faint Main Sequence Knee feature in NGC 2808 colour magnitude diagram. The difference between this point and the main sequence turn-off is a good age estimator that provides ages with unprecedented accuracy. Results: We find that NGC 2808 has an age of t = 10.9 ± 0.7 (intrinsic) ±0.45 (metallicity term) Gyr. A possible contamination by He-enhanced population could make the cluster up to 0.25 Gyr older. Although this age estimate agrees with the age coming from the classical turn-off method (t = 11.0 Gyr), its uncertainty is a factor ~3 better, since it avoids systematics in reddening, distance assumptions, and photometric zero point determination. The final absolute age indicates that NGC 2808 is slightly younger than other Galactic globular clusters with similar metallicity. Tables of the photometry are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A51

  11. Feasibility study design and methods for Project GEMS: Guidelines for Exercise in Multiple Sclerosis.

    PubMed

    Adamson, Brynn C; Learmonth, Yvonne C; Kinnett-Hopkins, Dominique; Bohri, Maria; Motl, Robert W

    2016-03-01

    The Guidelines for Exercise in Multiple Sclerosis (GEMS) program is a randomized controlled trial (RCT) examining the feasibility and efficacy of a home-based exercise training program based on recent physical activity guidelines and principles of behavior change for improving symptoms and health-related quality of life (HRQOL) in adults with multiple sclerosis (MS). The primary aim is to assess program feasibility in the four domains of process (e.g., recruitment, retention, and adherence), resources (e.g., communication, staff requirements, and monetary costs), management (e.g., time and accuracy in data collection/entry, and reporting of adverse events) and scientific outcomes (e.g., safety, burden, participant feedback and efficacy/outcomes). The trial will recruit individuals with mild-to-moderate MS-related disability across the United States who will be randomized into intervention or waitlist control conditions. All participants will complete home-based assessments (including wearing an accelerometer for 7 days and completion of a questionnaire booklet) prior to and upon completion of the 4-month program. Participants in the intervention will receive a 4-month home-based exercise program emphasizing aerobic and resistance training. Participants will be provided with exercise equipment, a DVD, a manual and a log-book. The exercise program will be supplemented with periodic newsletters in the mail highlighting principles of behavior change, and video-chats with an exercise specialist to provide motivation and social accountability. This trial serves to inform development of Phase II and III RCTs which can determine the actual efficacy and effectiveness of home-based exercise based on the MS-specific physical activity guidelines for improving symptoms and HRQOL. PMID:26655434

  12. The origin of GEMS in IDPs as deduced from microstructural evolution of amorphous silicates with annealing

    NASA Astrophysics Data System (ADS)

    Davoisne, C.; Djouadi, Z.; Leroux, H.; D'Hendecourt, L.; Jones, A.; Deboffle, D.

    2006-03-01

    Aims.We present laboratory studies of the micro-structural evolution of an amorphous ferro-magnesian silicate, of olivine composition, following thermal annealing under vacuum.Methods.The amorphous silicate was prepared as a thin film on a diamond substrate. Annealing under vacuum was performed at temperatures ranging from 870 to 1020 K. After annealing the thin films were extracted from the substrate and analysed by transmission electron microscopy to infer their microstructural and compositional evolution.Results.Spheroidal metallic nano-particles (2-50 nm) are found within the silicate films, which are still amorphous after annealing at 870 K and partially crystallized into forsterite for annealing up to 1020 K. We interpret this microstructure in terms of a reduction of the initial amorphous silicate FeO component, because of the carbon-rich partial pressure in the furnace due to pumping mechanism. Annealing in a controlled oxygen-rich atmosphere confirms this interpretation. Conclusions.The observed microstructures closely resemble those of the GEMS (Glass with Embedded Metal and Sulphides) found in chondritic IDPs (Interplanetary Dust Particles). Since IDPs contain abundant carbonaceous matter, a solid-state reduction reaction may have occurred during heating in the hot inner regions of the proto-solar disc. Related to this, the presence of forsterite grains grown from the amorphous precursor material clearly demonstrates that condensation from gaseous species is not required to explain the occurrence of forsterite around young protostars and in comets. Forsterite grains in these environments can be formed directly in the solid phase by thermal annealing of amorphous ferro-magnesian silicates precursor under reducing conditions. Finally, locking iron as metallic particles within the silicates explains why astronomical silicates always appear observationally Mg-rich.

  13. Chromium speciation in oxide-type compounds: application to minerals, gems, aqueous solutions and silicate glasses

    NASA Astrophysics Data System (ADS)

    Farges, François

    2009-09-01

    Cr K-edge XANES spectra were obtained for a variety of Cr-bearing model compounds containing Cr(II), Cr(III), Cr(IV), Cr(V) and Cr(VI), in which the Cr-site symmetry is D4h, Oh and Td. The centroid position of the pre-edge feature is a better indicator of the Cr valence than the edge position. In Cr-rich oxides, higher-energy transitions must be excluded in order to refine a robust valence for Cr. The pre-edge for chromates is not unique and varies as a function of the CrO4 2- moiety distortion, which is often related to Cr-polymerization (monochromate vs. dichromate). Both the analogy with the Mn K-pre-edge information and ab initio FEFF calculations of the pre-edge feature for Cr(III) and Cr(VI) confirm the experimental trends. This methodology is applied to the Cr K-edge pre-edge feature collected in gems (emerald, spinel and ruby), the layered minerals fuchsite and kämmererite, two Cr-bearing aqueous solutions and a set of sodo-calcic silicate glasses used for bottling sparkling white wine. In emerald and fuchsite, the Cr-site is differently distorted than its ruby or spinel counterpart. In a Cr(III)-bearing aqueous solution and sodo-calcic glass, no evidence for Cr(III) with Td and C3v symmetry is detected. However, minor amounts of chromate moieties (most likely monomeric) are detected in a glass synthesized in air. Preliminary spectra for the wine bottle glass suggest that only trace amounts of chromates might possibly be present in these glasses.

  14. Evaluating Aerosol Trends from 1960 to 2010 using HadGEM3-UKCA and EMEP Data

    NASA Astrophysics Data System (ADS)

    Turnock, Steven; Spracklen, Dominick; Carslaw, Ken; Mann, Graham; Woodhouse, Matthew; Forster, Piers; Haywood, Jim

    2014-05-01

    Atmospheric aerosols are an important component of the Earth system, interacting strongly with the Earth's radiative balance and climate. Substantial changes in anthropogenic aerosol emissions (and their precursors) have occurred in the last few decades with further large changes projected in the future. The response of atmospheric aerosols to these changes and the impact on climate are poorly constrained. Studies using detailed aerosol chemistry climate models and evaluation against observed changes over the latter half of the 20th Century are currently lacking. We use the HadGEM3-UKCA coupled chemistry-climate model to simulate changes in atmospheric aerosol concentrations over the period 1960 to 2010. The model includes a modal aerosol microphysics scheme and online tropospheric chemistry. Anthropogenic emissions are from MACCity inventory and the model is nudged to reanalysis meteorology from ECMWF. We evaluate simulated total and sulphate particulate matter against selected monitoring sites from the European Monitoring and Evaluation Programme (EMEP). The model's ability to reproduce the observed trends has been assessed in terms of the normalised mean bias factor (NMBF) and correlation coefficient (r2). Average NMBF for total aerosol mass was -1.05 and -0.43 for sulphate mass. Throughout the entire evaluation time period model biases have tended to become more negative for sulphate mass but less negative for total mass. The spatial correlation coefficient of modelled and observed sulphate mass for each year has remained similar throughout 1978-2010 with an r2 between 0.2 to 0.4, whereas for total mass it has been consistently low (

  15. Thermal properties of gem-quality moganite-rich blue chalcedony

    NASA Astrophysics Data System (ADS)

    Hatipogˇlu, M.; Tuncer, Y.; Kibar, R.; Çetin, A.; Karalı, T.; Can, N.

    2010-11-01

    In this study, thermal properties and thermal decompositions of dehydration behaviour of gem-quality translucent blue chalcedonies, without banding or crystalline centre structure, from the Sarıcakaya-Eskişehir region in Turkey were studied by means of X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometry (ICP-AES), Fourier transform infrared (FT-IR), thermoluminescence (TL), and simultaneously two thermal analyses of (DTA/TGA) spectroscopy. X-ray diffraction patterns of the blue chalcedony indicate the presence of two important chalcedonic silica phases with overlapped peaks at 4.26, 3.34, 2.28, 2.13, 1.82, 1.54, 1.38, and 137 Å. During heating from the room temperature to 300 °C, the thermoluminescence pattern of the blue chalcedony shows a characteristic peak at 210 °C. This peak may be due to unusually high traces of the impurities S, Th, Tl, U, and W. During heating from the room temperature to 1400 °C, the TGA pattern of the blue chalcedony indicates that the weight loss is due to the silanol water loss only, and that this loss occurs in a wide temperature range between about 170 and 954 °C. In addition, after making some corrections concerning the artefact mass gain, being due to the drift with buoyancy effect of the atmosphere in its TGA curve, the moganite-rich blue chalcedony shows a relatively lower mass loss of 0.202%. The DTA pattern of the blue chalcedony displays both endothermic and exothermic behaviours because of silica phase transformations. There are one distinctive sharp endotherm and three weaker endotherms at 806 °C. In addition, there is one distinctive sharp exotherm and one weaker exotherm at 1270 °C.

  16. Serial data acquisition for the X-ray plasma diagnostics with selected GEM detector structures

    NASA Astrophysics Data System (ADS)

    Czarski, T.; Chernyshova, M.; Pozniak, K. T.; Kasprowicz, G.; Zabolotny, W.; Kolasinski, P.; Krawczyk, R.; Wojenski, A.; Zienkiewicz, P.

    2015-10-01

    The measurement system based on GEM—Gas Electron Multiplier detector is developed for X-ray diagnostics of magnetic confinement tokamak plasmas. The paper is focused on the measurement subject and describes the fundamental data processing to obtain reliable characteristics (histograms) useful for physicists. The required data processing have two steps: 1—processing in the time domain, i.e. events selections for bunches of coinciding clusters, 2—processing in the planar space domain, i.e. cluster identification for the given detector structure. So, it is the software part of the project between the electronic hardware and physics applications. The whole project is original and it was developed by the paper authors. The previous version based on 1-D GEM detector was applied for the high-resolution X-ray crystal spectrometer KX1 in the JET tokamak. The current version considers 2-D detector structures for the new data acquisition system. The fast and accurate mode of data acquisition implemented in the hardware in real time can be applied for the dynamic plasma diagnostics. Several detector structures with single-pixel sensors and multi-pixel (directional) sensors are considered for two-dimensional X-ray imaging. Final data processing is presented by histograms for selected range of position, time interval and cluster charge values. Exemplary radiation source properties are measured by the basic cumulative characteristics: the cluster position distribution and cluster charge value distribution corresponding to the energy spectra. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

  17. Internationalizing Practical ChE Education: The M.I.T. Practice School in Japan.

    ERIC Educational Resources Information Center

    O'Connor, Andrea J.; Kandas, Angelo W.; Natori, Yukikazu; Hatton, T. Alan

    1999-01-01

    Describes the establishment, benefits, and difficulties of an overseas branch of the Massachusetts Institute of Technology's (MIT) chemical engineering Practice School for student internship study at the Mitsubishi Chemical Corporation's Mizushima Plant in Kurashiki, Japan. (WRM)

  18. Photometric properties for selected algol-type binaries. VIII. The triple systems DI Peg and AF Gem revisited

    SciTech Connect

    Yang, Yuan-Gui; Li, Shu-Zheng; Yang, Ying E-mail: yangyg@chnu.edu.cn

    2014-06-01

    New extensive photometry for two triple binary stars, DI Peg and AF Gem, was performed from 2012 October to 2013 January, with two small telescopes at Xinglong station (XLs) of NAOC. From new multi-color observations and previously published ones in literature, the photometric models were (re)deduced using the updated Wilson-Devinney code. The results indicated that the low third lights exist in two classic Algol-type binaries, whose fill-out factors for the more massive components are f{sub p} = 78.2(± 0.4)% for DI Peg, and f{sub p} = 69.0(± 0.3)% for AF Gem, respectively. Through analyzing the O–C curves, the orbital periods for two binaries change in the complicated mode. The period of DI Peg possibly appears to show two light-time orbits, whose modulated periods are P {sub 3} = 54.6(± 0.5) yr and P {sub 4} = 23.0(± 0.6) yr, respectively. The inferred minimum masses for the inner and outer sub-stellar companions are M {sub in} = 0.095 M {sub ☉} and M {sub out} = 0.170 M {sub ☉}, respectively. Therefore, DI Peg may be a quadruple star. The orbital period of AF Gem appears to show a continuous period decrease or a cyclic variation; the latter may be preferable. The cyclic oscillation, with a period of 120.3(± 2.5) yr, may be attributed to the light-time effect due to the third body. This kind of additional companion may extract angular momentum from the central system, which may play a key role in the evolution of the binary.

  19. THE POLARIZATION PROPERTIES OF INVERSE COMPTON EMISSION AND IMPLICATIONS FOR BLAZAR OBSERVATIONS WITH THE GEMS X-RAY POLARIMETER

    SciTech Connect

    Krawczynski, H.

    2012-01-01

    NASA's Small Explorer Mission GEMS (Gravity and Extreme Magnetism SMEX), scheduled for launch in 2014, will have the sensitivity to detect and measure the linear polarization properties of the 0.5 keV and 2-10 keV X-ray emission of a considerable number of galactic and extragalactic sources. The prospect of sensitive X-ray polarimetry justifies a closer look at the polarization properties of the basic emission mechanisms. In this paper, we present analytical and numerical calculations of the linear polarization properties of inverse Compton scattered radiation. We describe a generally applicable formalism that can be used to numerically compute the polarization properties in the Thomson and Klein-Nishina regimes. We use the code to perform for the first time a detailed comparison of numerical results and the earlier analytical results derived by Bonometto et al. for scatterings in the Thomson regime. Furthermore, we use the numerical formalism to scrutinize the polarization properties of synchrotron self-Compton (SSC) emission, and of inverse Compton radiation emitted in the Klein-Nishina regime. We conclude with a discussion of the scientific potential of future GEMS observations of blazars. The GEMS mission will be able to confirm the synchrotron origin of the low-energy emission component from high-frequency-peaked BL Lac objects. Furthermore, the observations have the potential to decide between an SSC and external-Compton origin of the high-energy emission component from flat spectrum radio quasars and low-frequency-peaked BL Lac objects.

  20. Photometric Properties for Selected Algol-type Binaries. VIII. The Triple Systems DI Peg and AF Gem Revisited

    NASA Astrophysics Data System (ADS)

    Yang, Yuan-Gui; Yang, Ying; Li, Shu-Zheng

    2014-06-01

    New extensive photometry for two triple binary stars, DI Peg and AF Gem, was performed from 2012 October to 2013 January, with two small telescopes at Xinglong station (XLs) of NAOC. From new multi-color observations and previously published ones in literature, the photometric models were (re)deduced using the updated Wilson-Devinney code. The results indicated that the low third lights exist in two classic Algol-type binaries, whose fill-out factors for the more massive components are fp = 78.2(± 0.4)% for DI Peg, and fp = 69.0(± 0.3)% for AF Gem, respectively. Through analyzing the O-C curves, the orbital periods for two binaries change in the complicated mode. The period of DI Peg possibly appears to show two light-time orbits, whose modulated periods are P 3 = 54.6(± 0.5) yr and P 4 = 23.0(± 0.6) yr, respectively. The inferred minimum masses for the inner and outer sub-stellar companions are M in = 0.095 M ⊙ and M out = 0.170 M ⊙, respectively. Therefore, DI Peg may be a quadruple star. The orbital period of AF Gem appears to show a continuous period decrease or a cyclic variation; the latter may be preferable. The cyclic oscillation, with a period of 120.3(± 2.5) yr, may be attributed to the light-time effect due to the third body. This kind of additional companion may extract angular momentum from the central system, which may play a key role in the evolution of the binary.